#38 - Francisco Gonzalez-Lima, Ph.D.: Advancing Alzheimer's disease treatment and prevention – is AD actually a vascular and metabolic disease?
Episode Stats
Length
2 hours and 32 minutes
Words per Minute
153.57965
Summary
In this episode, Dr. Francesco Gonzalez-Lima, a professor of neuroscience and pharmacology and toxicology at the University of Texas at Austin, joins me to talk about Alzheimer s disease and the vascular hypothesis that he and his colleague and collaborator at UT Austin, Jack De La Torre, introduced 25 years ago.
Transcript
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Hey everyone, welcome to the Peter Atiyah Drive. I'm your host, Peter Atiyah.
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thank you for taking a moment to listen to this. If you learn from and find value in the content I
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produce, please consider supporting us directly by signing up for a monthly subscription. My guest
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this week is Francesco Gonzalez Lima, a professor of neuroscience and pharmacology and toxicology at
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the University of Texas, Austin. In this episode, we talk about Alzheimer's disease. In particular,
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Francesco explains the vascular hypothesis of Alzheimer's disease, a hypothesis that his colleague
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and collaborator at UT Austin, Jack De La Torre, introduced to the field about 25 years ago.
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He makes the case that the central problem in late onset Alzheimer's disease is a progressive
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neuronal energy crisis, meaning impaired blood flow to the brain and impaired mitochondrial respiration.
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If the problem is an energetic crisis, Francesco argues, then we can improve the supply of energy
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and blood to the brain. We could probably make progress in the prevention of Alzheimer's disease.
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We of course get into great detail at about all of this stuff. And to paraphrase my friend and my
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colleague, Richard Isaacson, who I've already spoken with on the podcast a while back, as you may
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remember, and who directs the Alzheimer's prevention clinic at Cornell, if you have a brain, you don't
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want to miss this episode. So without further delay, here's my conversation with Francesco Gonzalez Lima.
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Thank you so much for making time to see me on a Friday afternoon.
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This is actually my first time to the university. I've been to Austin many times, but I never seem
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to be north of downtown. So it was beautiful to drive by the medical center on the way here.
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It's kind of amazing. I haven't even been to a football game, which I hope to one day do at some
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I've been here as a tenure professor for 27 years.
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Yes. And during that time, I started out in pharmacology and toxicology and moved to psychology,
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just added that. Then the recruiting institution was the Institute for Neuroscience.
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And now I'm a faculty also at the Department of Psychiatry at the new medical school.
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And we were talking a little bit earlier, you describe yourself as a behavioral neuroscientist.
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Tell me a little bit about what that title means. Why behavioral?
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My original training as a PhD was in anatomy and neurobiology. And then as a postdoctoral fellow,
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I tried to understand how the brain related to behavior. And I did that work as a Humboldt fellow
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in Germany. And that was my introduction to the study of functional brain mapping and how we could see
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behavioral functions reflected in brain activity. This was the time where we developed the
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fluorodeoxyglucose autoradiographic method in that German group in Darshten that later became the key
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to develop FTG PET, the first functional imaging technique in humans.
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Yeah. It's interesting you say that because I noticed that a number of patients when I talk to them
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don't understand sometimes the difference because I don't think physicians explain the difference
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between functional studies and imaging studies. And I remember feeling very fortunate in medical
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school during a radiology rotation where one of the residents sat me down and explained the
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difference. And the PET, of course, the FGD positron emission tomography being a great example of a
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functional study. It's not giving you anatomic resolution. It's giving you functional resolution
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with respect to glucose uptake. And similarly, you would now have functional MRI, which is doing
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the same sort of thing. And so, yeah, that's a very important distinction.
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Especially important if you want to be able to determine a disease in a very early stage
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in which there are no structural changes in the brain that can be seen at least at the microscopic level.
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And having functional techniques, you're able to identify these functional changes even before
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So, I know you're a gentleman who has spent time all over the place. You were born in Cuba. You left Cuba
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when you were quite young. You spent time in Costa Rica, Venezuela. I mean, where did you-
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And Puerto Rico, of course. All of those things, at what point did it become clear to you that you
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were interested in the brain? I think my father was a veterinary doctor. And originally, my interests
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have to do with working with animals. But soon, I realized the nervous system was so important for
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the entire health of the animal and the behavior of the animal. So, I started to move away from just
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a more general interest to something that had to do more with the brain. But I would say my key
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influence happened as an undergraduate at Tulane University in New Orleans, when one of my
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professors, Dr. Joan King, dissected a brain in one of our classes. And this was an undergraduate
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honors class. And it was fascinating to me. And I joined her lab to do an honors thesis, working on the
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relationship between the brain, hormones, and behavior in animal models.
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It's so interesting. I think back to my own time in medical school. There were clearly a subset of my
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colleagues who were so captivated by the brain, which in gross anatomy really doesn't depict a
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fraction of its brilliance, right? Unlike the heart, where certainly microscopically, there are things
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about the heart that are relevant. You can't see the Purkinje fibers. You can't see the AV node or the SA node.
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There's so much that is invisible to the naked eye. But for the most part, you can appreciate the
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brilliance of the heart at the macroscopic level. But then there are other organs that, you know, on the
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other end of the spectrum, get no attention, like the liver. I mean, macroscopically, it's just a lump of
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whatever. But of course, what's happening inside the liver, to me, makes it one of the most
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remarkable organs. But the brain is an organ that has such a unique look, right? Grossly, it looks so
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distinct. The tissue looks so distinct from all of the other tissue outside of the central nervous
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system. And also, to this day, I would say our knowledge of the brain must be far, far behind that
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of any other organ at the sort of physiologic signaling level. I mean, is that a fair assumption?
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Oh, yes. I agree completely. And I would say using the same analogies that you have, the heart,
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you can think of it as a mechanical engineer, a pump, a hydraulic pump, whereas the brain is more
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of an electrical engineer, where you have lots of circuits. And the liver, for that matter,
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will be a chemical engineer, where we break down all of these substances that the body consumes.
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I actually love that. I've never thought of what you just said. And that is a great way to explain
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the different types of engineering. The kidney would be some sort of sanitation filtering engineer. I
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mean, we could really, yeah, yeah. Environmental. Yeah. And so in many ways, the brain is probably not
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only electrical engineering, but it's computer science engineering. There's so much going on there.
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Right. You hit in a very important point. One cannot simply look at the brain the same way that you look
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at other organs. Because of that circuit property, it allows the development of computational power.
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So the brain uses the circuits, not just for communication, which is the most obvious function,
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but to determine and compute outcomes that they are used to guide the other tissues in the body. For
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example, the musculoskeletal system cannot do anything on its own without the commands that are the result
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of computations from the nervous system. So all of our behavior results from how the nervous system
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can process our experiences and our current situations. And it's become not in the same way
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as a computer works that is a serial device. The brain is a very redundant parallel system where there
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have to be a lot of convergence between different regions that are computing for that to be acknowledged
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as the way to go in a behavioral point of view. So for a person listening to this who might not have
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the luxury of knowing some of the nuances about the brain that you do, when you're talking to an
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audience that is, presumably most people are interested in the brain because of brain pathology.
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It's, you know, once a disease strikes the brain, everybody becomes well aware of how much it's doing
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because the absence of that function leads to such an obvious downside. How do you describe for people
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this notion of convergence and redundancy and overlap? I mean, obviously there's a very strong
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evolutionary reason. What are some examples of those and how those things are, these processes are
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preserved in terms of, because you use, I like the use of, I'm an engineer, so I do like the use of talking
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about serial versus parallel processing. Maybe expand on that a little bit. In reality, all of the anatomy
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is redundant and parallel. At least, for example, we have bilateral symmetry, you know. Everybody knows
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we have two hands, two legs, two eyes. We probably could have done it with one eye, but the way the system
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works is that it creates redundancy. And then, for example, the circulatory system is the same. You have
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parallel blood vessels where you can get the blood from one point to another in more than one way.
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And, of course, when you sit, when you put your elbow down, you can compress a blood vessel, but there's
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still another route that can be used. It's like coming from the university to the downtown area. You have
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many options to get from one point to the other. So, in the brain, this is maximized to its extreme. It's an
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organism specialized for this large amount of communications. In other words, having so many
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highways and avenues where information can go through. So, in that sense, differs from other
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organs where you have a pattern that repeats itself, and the redundancy is only on that pattern. Here in
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the brain, the redundancy is combined with the acquisition of new networks or circuit auctions
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that are not possible if you only have one design. So, you have multiple designs. If you want an
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analogy, for example, when NASA was sending the man to the moon, they have like a hundred computers doing
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the same computation. And then they look at the output, and they see which is the output that is
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repeated more often. And that's the one that those coordinates are the ones that they're going to pass
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on. The brain uses that strategy, and that's what I mean by convergency. In other words, you have all
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of these multiple parallel systems, and they are doing these computations, but only the ones that converge
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on the same solutions are the ones that are acknowledged and move on for the next stage.
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And when you look at other species beyond humans, how much of that redundancy do you see as you go
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down the evolutionary chain or down the food chain, maybe is an easier way to think about it. I mean,
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at what presumably, you know, chimps and cats and dogs are very similar, but is there a point at which
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it very suddenly stops, or does it simply diminish to the point where, you know, when you're looking
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at a simpler organism like a worm, for example, I don't even know what the nervous system of C.
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elegans looks like. Well, definitely mammals and primates in particular, where basic plan is the same,
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and most of the differences have to do with which of the networks are more developed than others.
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So, in primates, we have the cerebral cortex becoming the dominant component in the brain.
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This is, to a certain degree, the same thing in all the mammals, but then other regions of the brain
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have more similar contribution. When you go down to, for example, erectiles or amphibians,
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the midbrain, the mesencephalum, is the largest part of the brain, not the portion where we have the
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cerebral cortex. And what that means, basically, is, in addition to this parallel processing that we
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have, information goes through several hierarchical stages. And at every one of these stages,
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similar processing is done, and you add an additional piece of information when you move it on.
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For example, you can respond at the level of the spinal cord. That would be the lowest level of
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response. That would be, for example, a reflex. Like, if you tap somebody's knee, you transiently
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lengthen the patellar tendon, the knee kicks out to straighten it or reduce the length. And that
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is happening outside of the brain. Yes. However, when you tap the knee, the information also goes
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to all the levels of the nervous system. In that case, you saw the spinal reflex being manifested.
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But the person still knows. Yes. They felt the sensation and they know what happened.
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So the same was happening at different hierarchical level processing. So behaviorally speaking,
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when we respond to a stimuli at very basic level, like what you indicated, like the spinal level,
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we call it a reflex. So that would be the most basic behavioral response. But that means that you
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are not seeing what is happening at the other levels. But for example, in a frog that is following
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an insect, a worm as it's moving, the frog would orient to the movement. As long as the worm is moving
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in the same direction as the long axis of the body, you have the same worm that is a fake worm where
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it's moving in a direction perpendicular to the long axis. It's long axis. Yeah.
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The frog will not follow. So the pattern isn't recognized. So if a frog sees a worm moving in
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the normal direction a worm moves, it knows that pattern. If it sees the exact same food source
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standing up and walking on the side, it's not going to pursue it. It's not pursuing it.
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But in order to do that new computation, then you needed the level of the midbrain. So the midbrain
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becomes now the point at where the decision is made and whether to follow and then eventually snap
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and capture the worm. So the submammalian species primarily operate at that level. And they have well
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defined. Instead of being called a reflex, we would call this like release stimulus. Release stimulus
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creates that generates a pattern. There is a pattern generator that recognizes it. But then in mammals,
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we have to move information to the level of the thalamus that is in the middle of the brain, but
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higher than the midbrain. And then from there, the majority of the mass of the brain is in primates and
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humans in particular is in the cerebral cortex. So we have to pass that information to the cerebral
00:20:00.600
cortex and then feed that back down to the output systems. So it might be a way of oversimplifying,
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but one could think of it as the brainstem and spinal cord are responsible for these reflexes. For
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example, we breathe without thinking because our brainstem allows us to. We recoil from pain without
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thought because of these things. The midbrain took it up a notch by basically allowing for that stimulus
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response. But the thalamus then becomes the gateway to the cortex where we can do this higher processing.
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That's probably an oversimplification. And the main contribution of this thalamocortical system
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is to allow us to inhibit behavior. In other words, not to respond in a more immediate short-term
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manner. So the ability to delay a response and to try to compute what are the consequences
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if we were to make that response. This is what really is brought up by our more elaborate cerebral
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cortex. So the majority of the influence of the cerebral cortex on subcortical levels.
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It's inhibitory. It's not excitatory. No. And engineers actually don't understand this very well.
00:21:11.160
When they, for example, try to create a prosthetic device to have somebody send neural impulses to move a
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leg that is paralyzed. They try to create this as an excitatory type of phenomenon.
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But what the brain is doing is not like that. What the brain is doing is inhibiting all possible
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vectors of movement in a space and then selectively releasing some of them by sending an inhibitory
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signal to that. Yeah. It inhibits the inhibitory signal, thereby selectively, quote unquote,
00:21:46.680
releasing activation. Yes. And when you do that, you have more control because you are actually,
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for every movement, you're not just working as a puppet where you're trying to only emulate those
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vectors. You're controlling all of the other possibilities. So you sort of carve a tunnel in
00:22:06.520
space, which are the only vectors that are allowed to be manifested. So the engineering of the brain
00:22:15.160
in this sense requires this more effort in order to achieve something that could have been achieved
00:22:21.800
by a more simplified system because it wants that control.
00:22:27.160
So is it safe to say that more of the pathology that we see in the brain occurs in the cortex than
00:22:35.640
in the midbrain? For example, Parkinson's, I guess, would be partially midbrain, right?
00:22:41.720
Yeah. Are there great examples of common pathology in the brain stem?
00:22:45.400
Yes. But from the point of view of dementia and neurodegenerative disorders with the exception of
00:22:54.680
Parkinson's disease, these are primarily cerebral cortex. This is where you see especially the
00:23:01.880
initial functional deficits and later on the atrophy and loss of tissue. But most of the diseases of
00:23:11.400
all age that affect the brain primarily target these cortical regions.
00:23:16.920
And that's obviously the thing that I most wanted to chat with you about because you and your
00:23:21.800
colleagues, you have a different point of view on Alzheimer's disease. And in many ways, it's when you
00:23:29.000
read your work or hear you guys talk about it, it doesn't sound that hard to believe. It's actually
00:23:34.280
quite a reasonable hypothesis. Let's start with the conventional thinking on Alzheimer's disease,
00:23:39.480
which needs to be caveated with the fact that there is no disease for which we have had a greater
00:23:45.480
failure in our ability to treat it than this one. Even cancer, which one could argue we're not
00:23:51.560
exactly hitting it out of the park on, we at least have some success. We can point to very,
00:23:56.840
very specific successes, not only in terms of prevention, for example, simply the recognition
00:24:02.520
that something like smoking could cause cancer led to an enormous reduction and a continued enormous
00:24:07.800
reduction in the onset of that disease, but also very specific chemotherapeutic regimens for a subset
00:24:13.880
of cancers, particularly liquid cancers. And now more recently, we've seen some real breakthroughs
00:24:18.920
with things like checkpoint inhibitors, uneven solid organ tumors. So at least with cancer,
00:24:23.240
we have some sense of we're making progress. Certainly with heart disease, we've probably made the most
00:24:28.360
progress. And yet with this disease, it appears we have not made a shred of progress. What is the typical
00:24:37.480
explanation for what causes Alzheimer's disease and therefore, by extension, what the path should be
00:24:44.440
to prevent it or treat it? You're completely right. We have not made any significant progress in
00:24:52.760
Alzheimer's disease research. This is the largest failure of the biomedical research enterprise in the
00:25:00.840
world during my lifetime. And the main reason is we have remained faithful to an initial observation that
00:25:12.040
was done or published at least in 1907 by Lois Alzheimer's that indicated that he saw these abnormal
00:25:20.680
depositions in the brains of an individual after that individual died. This individual was 51 years old when he died.
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But Alzheimer's was actually a psychiatrist, not a neuropathologist like it's pointed out in books.
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He worked in a psychiatric hospital. It was part of the original group led by Kreppling in Munich.
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And they were studying mental illness. And in those days, it was believed that what we call
00:25:52.040
nowadays dementia was a form of mental illness. And he was surprised by this young patient that was
00:25:59.240
showing these early signs of dementia, you know, in his 50s. And already by the time he died, that person
00:26:06.200
had been suffering for many years. So what Alzheimer's described as in the brain of that individual has
00:26:13.480
Alzheimer's disease is not the same disease that is happening in older people. It's not the same
00:26:21.960
disease that is the most common type of dementia. And this is being the most basic misunderstanding
00:26:28.920
from the beginning. Historically, there was a competition between two groups, one in Prague,
00:26:35.560
in Czech Republic, at that time was under German rule. And Oscar Fischer published studies,
00:26:43.400
where, for example, he looked at 16 brains from patients that had what was called senile dementia.
00:26:51.560
That is the type of dementia that was showing up in people after they were 60, 70, 80 years of age,
00:26:59.480
not these younger individuals. And he described some of these same abnormalities that later
00:27:06.600
that Alzheimer's published, but for that single case. However, Krepling was a rival of that group,
00:27:14.680
especially about Fischer who was Jewish. And so he published in the first book that talked about
00:27:21.720
Alzheimer's, the first textbook of psychiatry that was published by Krepling. And then he say,
00:27:27.640
oh, what we're seeing in these old people, this type of dementia is what Alzheimer's described in that
00:27:34.680
younger individual. And from there on, there was a movement away from factors that were related to
00:27:41.800
aging and to say, this is a disease that is invading somehow. And it's not something that is building up
00:27:50.600
over the years. Of course, this is actually not the case. So nowadays they try to have a compromise and
00:27:58.040
say Alzheimer's disease, there is early onset or familial, which is primarily familial. There's some
00:28:05.640
evidence for inheritance. But nine out of 10 cases of what is referred to as Alzheimer's disease,
00:28:13.640
there is absolutely no inheritance or familial component, which is one of the greatest fears of
00:28:22.760
people when they have patients with dementia in their family. And not only that, it's aging related.
00:28:30.680
And because it develops very slowly over the decades, it provides an opportunity to intervene,
00:28:39.240
to determine what are the risk factors that are behind, and to do an intervention. If you take the
00:28:46.040
other approach, that this is a disease of these abnormal proteins, and it can happen early on,
00:28:51.960
then you have a very different strategy. So the whole field has been dominated primarily by what is called
00:28:59.720
the amyloid beta hypothesis. This hypothesis is completely, absolutely false. It has no
00:29:08.840
relationship whatsoever with what we see in the older people that develop dementia. It has a relationship
00:29:19.560
with some of these early cases that, like the one that Alzheimer's described, and they have a familial
00:29:26.200
component, and that there is a somatic genetic component. Let me just interrupt for a second to make sure
00:29:32.120
I'm understanding. This is obviously such an important point that I want to make sure I'm clear and that
00:29:37.960
the listener is clear. Now, the case that Alzheimer's found in 1907, I have to assume that was a PSEN
00:29:44.120
one or two mutation. That was what we now see accounting for less than one percent of Alzheimer's disease,
00:29:49.560
but it is probably the closest to a fully penetrant gene that results in Alzheimer's disease. Has that ever been
00:29:56.200
confirmed? Are there any biologic specimens remaining from that particular individual who was so young?
00:30:01.560
There are slides available, but it has never been confirmed. And the patient died in 1906 after many
00:30:09.320
years with this chronic dementia in that hospital in Munich. And he was deteriorated in every other
00:30:16.760
respect. By that time, he was unable to move and carry on on activities of daily living. So he'd been
00:30:24.120
suffering from this for many years. Which is not unlike what we can see in the rare patients that do have the
00:30:30.520
PSEN one or two gene, which is, it can easily take hold in the forties. I unfortunately have a patient
00:30:36.760
whose mother is, you know, debilitated in her mid fifties. Now it turns out she doesn't have the gene,
00:30:41.480
which was a surprise to a lot of us. We assumed because it had taken hold so early, but the autopsy,
00:30:47.640
the pathology that they could see, which at the time was limited to very gross things relative to
00:30:52.440
today. Gross for the listener. I don't mean gross as in disgusting. I mean gross as in visible through
00:30:57.400
a microscope. Was this the first time that amyloid beta was observed? No. The first time
00:31:03.880
was done by Oscar Fisher in the senile dimension. So Alzheimer's was basically describing a phenotype,
00:31:12.040
but without a pathologic explanation or characteristic. Yes. But because it was happening so early,
00:31:18.280
then it moved the people away from the idea that this has something to do with senility,
00:31:24.360
with the older deterioration that happens as a function of aging. So they say, oh no,
00:31:30.840
this can happen early on. So aging cannot be a primary contributor. So even though a very small
00:31:41.080
percentage of people that are described as having Alzheimer's belongs to this early onset, over 90%
00:31:49.880
of the research is focused on that group. And the reasoning is because it's the same disease,
00:31:58.520
which is a false premise. If we find out what's happening in the early onset, and we model that
00:32:05.320
in animals by doing this genetic manipulation, then we can fix the more common senile, older age,
00:32:13.800
late onset dementia. And that false premise is what has been driving all of these failures.
00:32:20.920
Because yes, they have been able to detect genetic changes. They can manipulate this.
00:32:26.360
I was able to work, examine the brain of the first amyloid precursor mouse model that was developed.
00:32:33.160
And one of the first things that I noticed in the brains, even before there was any amyloid deposition
00:32:39.240
in that model that they had inserted, it was a transgenic mouse model. They had taken away the
00:32:46.120
native gene from the mouse and replaced that gene with one that was abnormal for a patient with early
00:32:53.800
onset Alzheimer's. But even before that gene could start any observable deposition of amyloid,
00:33:01.800
these brains, by that very manipulation, were abnormal. They had severe atrophy in, for example,
00:33:10.520
the corpus callosum, the bundle that communicates the two hemispheres. And the region of the
00:33:16.280
hypocampal formation has lost one third of its volume. So the intervention itself may have altered
00:33:23.000
the resilience, if nothing else, of the brain. Yes. And of course, then these animals show all kinds
00:33:29.240
of behavioral abnormalities. But these things were happening even before there was any amyloid
00:33:35.400
deposition. So it was clear that having a gene with these abnormalities, even before you can see that
00:33:44.760
product building up is enough to distort how the brain develops. So this has been the main problem.
00:33:53.080
And because biology, just like when I started studying biology, my major was called cell and
00:33:59.160
molecular biology. And that became the dominant orientation in biology. So people who do this
00:34:08.040
research oftentimes don't have a very good understanding of the brain as a whole. And they
00:34:13.800
just focus at that molecular level. And in a way, they're trying to find the answer where the light is,
00:34:20.680
that is the light that they can use. And trying to ignore that this is really a disease of
00:34:26.760
all age that involves a long development. And that there is absolutely no correlation,
00:34:34.040
no relationship between the amount of, for example, amyloid beta deposition,
00:34:40.440
and the onset of memory deficits, cognitive impairment, or the progression of the disease.
00:34:47.480
There are brains of individuals that I have the fortune to examine here in Austin.
00:34:53.160
Hassan, primarily a neuroanatomist, a functional neuroanatomist. I collaborated with the neuropathologists
00:34:58.680
here. And the brains of these people who were cognitively normal after they died,
00:35:05.080
they couldn't differentiate them from the ones that were diagnosed with Alzheimer's based on
00:35:11.240
amyloid and neurofibrillary tangled depositions.
00:35:14.520
That's an enormous statement. It doesn't call into question the causality of amyloid.
00:35:20.600
It just calls into it the necessity and sufficiency of it. In other words, it could be that you have to
00:35:28.440
have, I mean, I'm making this up, but to illustrate a point within logic, it could be that you need to
00:35:34.120
have amyloid beta deposition to cause dementia, but that is not sufficient. It is only a necessary
00:35:41.160
condition and that you might need other factors to coalesce around it. The obvious example that
00:35:46.200
comes to my mind is LDL and ApoB, which is necessary for cardiovascular disease, but not alone sufficient.
00:35:52.360
You still need an inflammatory response and an immune response.
00:35:55.640
I go beyond that point. What I'm saying is against the dogma.
00:36:00.280
You're saying one step further than that. You're saying that not only is the deposition of amyloid
00:36:07.480
not correlated strongly enough, it might not even be causally related.
00:36:12.440
Not even. It is not causally related to what we call primarily Alzheimer's disease, which is this
00:36:21.000
majority of late onset. That's not true for the early onset. What I'm saying is that there are two different
00:36:28.280
diseases. The early onset, there is a role for this amyloid deposition. You can demonstrate this.
00:36:34.280
In other words, if you take autopsies of 50-year-olds that die from heart disease, cancer, or accidental
00:36:42.280
death, and you examine their brains relative to 50-year-olds who die from early onset dementia,
00:36:48.600
the relationship is more clear. Oh, it is clear.
00:36:51.640
The amyloid beta is playing a causal role. Yes, there is no question. And you can find the
00:36:56.920
genetic mutations and you can induce it in the animal, but that's not the case in the late onset.
00:37:03.320
And the neuropathologists will tell you if they don't know what the clinical picture was,
00:37:11.400
they wouldn't be able to say that this was what they refer to as a probable Alzheimer's disease.
00:37:18.520
So when they see exactly the same pathology and then there's no evidence of cognitive deterioration,
00:37:24.280
they just diagnose that brain as possible Alzheimer's disease. So this created a circular
00:37:31.000
definition. To be clear, to close the loop on that analogy with heart disease,
00:37:37.000
you would have to know that there are cases where patients have significant dementia that by all other
00:37:44.200
metrics is consistent with Alzheimer's dementia and not Lewy body or something else. And there is an
00:37:49.800
absence of amyloid beta deposition. And what percentage approximately, I know it's hard to
00:37:56.760
know these things because we don't always get autopsies, but in your experience, what percentage of
00:38:03.160
patients who die with or from Alzheimer's disease that is late onset do not have the histopathologic
00:38:12.280
features of amyloid beta? The majority of patients that are diagnosed as Alzheimer's disease,
00:38:19.480
pro-Alzheimer's disease when they die, have the same level. It's not that they don't have,
00:38:26.760
because it's an age-related deposition, the same levels of all the patients that are comparable age.
00:38:34.520
And the only reason that they are labeled Alzheimer's is because they have the dementia. The pathology
00:38:41.480
cannot really tell them apart. If you give these two pathologies blind to the medical diagnosis or
00:38:48.600
clinical examination, they won't be able to tell apart which are the ones that are actually demented
00:38:56.520
and which are not, if you do it in a match. There is a large degree of variability and pathologies are
00:39:02.920
not quantitative. Pathology is an approximation. You look at only a few sections through the cortex,
00:39:10.440
and then you give a certain proportion of the findings that are found that you see as categories. But
00:39:18.760
even when I have done this personally, in 2001, we published in the Journal of Neuroscience,
00:39:25.960
a study where we use brains from people who die from Alzheimer's. The main difference from my study,
00:39:32.520
from what's been done before, is that we were able to obtain brains with only a few hours after the
00:39:41.560
individuals had died. We call it a very small post-mortem interval. And I was able to do this
00:39:48.760
by collaborating with the Institute in Arizona. There is a city called Sun City, Arizona. And they
00:39:56.600
have a Sun City Health Center, which actually ascribes to these amyloid and neurofibular rectangle ideas.
00:40:04.200
But what we did with them was we went, we traveled there and we, my PhD student, we collected these
00:40:12.120
brains, controlled brains and brains of people who have died, die of Alzheimer's. Some of them,
00:40:17.720
we were able to collect them fresh right there. And were you and your team also blinded to the
00:40:24.040
circumstances of the death prior to the autopsies being performed? No. What we did is we collected all
00:40:31.400
the brains and they were, I sectioned them into pieces and these pieces then were frozen. And then
00:40:39.400
one sample would remain there. I see. I see. So you did everything in parallel. Yeah. It would be
00:40:45.400
chipped here to Austin. And once the samples were chipped, they were coded. But when we were there,
00:40:51.800
no, we knew when somebody died because I had a pathologist with me who had to certify.
00:40:58.120
They were dead so that we could immediately... But when the pairwise results were evaluated,
00:41:05.000
the evaluator was blind to the clinical circumstances of the patient's death? Yes. What we did in that
00:41:12.120
study was we were not only interested in just looking at amyloid plagues and neurofibular rectangles
00:41:19.400
being done. We were interested in seeing, is there any biochemical change that could account
00:41:26.760
for this so-called hypometabolism, this decrease in energy metabolism that is seen early in Alzheimer's?
00:41:36.440
Is it generally well-regarded bringing it back to some of your earlier work in PET? I assume it is
00:41:41.720
generally agreed upon that patients who are in the stages of cognitive decline have hypo-functioning
00:41:49.640
metabolism. So their PET scans show less glucose uptake in the brain. Is that generally acknowledged?
00:41:55.160
And not only FTG PET, when you do also cerebral blood flow, you find the same. When you do fMRI,
00:42:03.720
arterial spin labeling to look at blood flow, every technique that has been used has demonstrated
00:42:10.840
that first it was with mild Alzheimer's cases, but more recently also with the so-called mild cognitive
00:42:18.840
impairment. And in those cases there is hypometabolism. And the hypometabolism is primarily not in the
00:42:32.120
regions that become atrophic. Later on in the disease, like in the temporal lobe, it's primarily in the
00:42:40.120
posterior cingulate cortex. One region of the brain that is in the medial part in the center
00:42:46.680
of the brain. This area is the one that you can see having earliest sign of hypometabolism.
00:42:54.120
And from a phenotypic standpoint, what does it control in the normal brain?
00:42:59.000
This region provides the major input to what is called the entorhinal cortex, which is the part of
00:43:08.040
the temporal lobe that then feeds into the hypocampal formation. So what essentially is happening is you
00:43:17.800
have a functional disconnection between the main input to the entorhinal cortex. The entorhinal cortex
00:43:26.440
is the primary source of inputs to the hypocampal formation. So when you functionally denervate
00:43:34.760
a region in the brain, eventually that leads to atrophy from that region that is receiving the stimulus.
00:43:43.000
It is receiving that. Just like happens when you denervate a muscle in the periphery,
00:43:48.040
there is atrophic action and action that that region survives because it's being stimulated by the
00:43:54.680
other one. So people have missed, when you study pathology, you don't study these functional changes
00:44:02.600
and you don't look at the system as a network of pathways that influence functionality. You're seeing
00:44:09.320
the end result, what has happened after all of these processes are taking place over the years.
00:44:16.520
So by doing that, you cannot infer these other phenomena.
00:44:22.120
So if you take an animal like a mouse and you just take out the, it's the posterior cingulate?
00:44:27.960
Yeah. If you lesion that in a rat or a mouse acutely, which is not the same as what's presumably
00:44:33.800
happening in this disease state, what is the immediate phenotype of that animal or behavior?
00:44:39.880
Well, you don't have to lesion it. You can functionally deactivate it, which is more
00:44:46.040
similar to what is actually happening in Alzheimer's. It's not that this region is damaged structurally.
00:44:52.120
Right. It's just functionally not allowing the conduit.
00:44:56.440
Yeah. Affecting that network that is providing the main input to the hippocampal formation.
00:45:01.400
You get the same kind of memory deficits that are characteristics of the initial stages of
00:45:07.560
dementia. And is that because of the role the hippocampus plays in the consolidation of memory,
00:45:13.480
or is it to do more with the target in the temporal lobe?
00:45:17.240
It is because it's a network, not a single region. In other words, for example, long time ago,
00:45:25.720
in the 1930s, there was a circuit that was defined by an American neuroanatomist called James Pappes,
00:45:33.880
also pronounced Pappes. And he describes the connections between the cingulate cortex,
00:45:40.840
this parahypocampal cortex that we now primarily refer to as the entorhinal cortex,
00:45:47.160
and then from there to the hippocampal formation. From the hippocampal formation,
00:45:52.280
the main output goes to a region called the mammillary bodies. And then from the mammillary
00:45:58.040
bodies, it goes to the anterior part of the thalamus. And then from the thalamus, it fans out the
00:46:05.320
projections back into the cingulate cortex. So it creates a circle. And this is often being referred
00:46:12.200
to as the limbic circuit of papers. And we know it has to do with emotional memory formation because
00:46:20.760
events that have a large emotional signature are the ones we store.
00:46:29.640
Yes. So if you affect this system anywhere in this system, you get a memory disease and they just
00:46:38.520
have different names. So for example, people that have chronic alcohol, they develop sometimes,
00:46:46.280
it's referred to as a Wernicke's-Korsakov dementia, also known as Korsakov psychosis.
00:46:52.600
You can get this from B vitamin deficiencies as well.
00:46:55.880
B1 deficiency, thiamine deficiency in particular. You look at the pathology of the brain. Where is
00:47:02.760
the damage? The damage is primarily in the mammillary bodies. Well, the mammillary bodies is the main
00:47:09.240
output from the hippocampal formation. So whatever the hippocampal formation is contributing,
00:47:14.040
if you are knocking down his main output target, you get the same thing. Then in a second place is the
00:47:21.720
hippocampal formation itself, then the enteroendocortex and so on. All you have damage in any part of the
00:47:27.960
surgery system. There's also something called diencephalic retrograde amnesia that happens with
00:47:33.880
thalamic lesions. Well, this is when these lesions interfere with these anterior thalamic areas. So really,
00:47:41.240
in order for us to see the memory problems that we have linked usually with Alzheimer's dementia,
00:47:48.520
you have to engage this system because that system is part of the brain regions in which this is
00:47:55.000
operating. You use the term retrograde there. For the listener, we should explain the difference
00:47:59.480
between retrograde and antegrade amnesia. I'll let you do that quickly. But of course, my follow-up
00:48:04.520
question will be, in the earliest stages of dementia, is the bigger issue the inability to
00:48:10.520
form new short-term memories, which would be a form of antegrade amnesia? That would happen before the
00:48:15.800
retrograde amnesia, which is later. Yes. Let me explain. In the early Alzheimer's disease,
00:48:21.080
the main problem is not in this limbic circuit. When that happens is when you can see the hypometabolism.
00:48:30.200
That's when you can see the behavioral changes in the individual as well. But before that,
00:48:36.040
in the prefrontal cortex, especially the lateral, we call dorsolateral prefrontal cortex,
00:48:42.760
you have a functional deficit that is interfering with what we call working memory. So you can think
00:48:51.960
of memories as having three modes or temporal stages, an immediate memory mode where you can remember
00:49:00.760
things for only a few seconds. Tell me your phone number and I have to write it down. That's correct.
00:49:05.720
That's the perfect example. A clinician will do this by giving a string of numbers to people,
00:49:12.920
and people will be able to remember approximately seven numbers. So it is usually seven plus or minus two
00:49:23.640
items. And this is the reason why the telephone numbers have seven digits, because most people,
00:49:30.360
after reading seven digits, turning around to try to punch those numbers in the phone, if there are more
00:49:37.000
than seven, they drop, some of them. This is this immediate memory mode. But for memories to happen,
00:49:44.520
they have to move from this immediate memory mode to a more recent memory mode. So the immediate,
00:49:49.880
that movement from immediate to recent is done by this prefrontal cortex. So the initial deficit that
00:49:56.440
you see in Alzheimer's and all of these types of dementia of all age is in this more immediate memory
00:50:04.120
memory mode. And one way we refer to this is also working memory. So for example, you come out of your
00:50:10.440
house and you lock the door. But after a few seconds, you're working to your car. Then you ask, did I lock
00:50:18.040
the door or is it unlocked? And then you have to go back and check. So this is the first thing that you're
00:50:26.840
going to have. And it happens physiologically as a function of aging. And this is the first one,
00:50:32.040
these working memory things are. So the prefrontal one is the initial signal that there is a memory
00:50:39.320
problem. This is before. And this is an anti-grade memory. In other words, it's a new memory that you
00:50:45.880
want to form. So this is the first thing that is affected. But once the memory are in the recent memory
00:50:51.800
mode, this, for example, would be your phone number, which is one of the easy seven digits to remember because
00:50:57.480
you're so familiar with it that it's now become quote unquote permanent memory.
00:51:01.080
By repetition, by exposure to the same items, this reverberate in that limbic circuit that I just
00:51:08.120
told you. And the hippocampal formation has an inner circuit that is crucial for that. So it is crucial
00:51:15.320
for that forming. And then you being able to retrieve that number again. So when that circuit becomes
00:51:22.360
engaged at any point, then you start having this retrograde memory problem. You cannot remember
00:51:28.120
your number. Which is interesting. That's the point at which the family members tend to really
00:51:33.720
notice what's happening and become concerned. Yes.
00:51:36.360
But the patients tend to become concerned much sooner. The patients become concerned
00:51:41.560
with the anti-grade memory deficits. You're absolutely right.
00:51:45.320
How do you distinguish between something you said a moment ago, which was this slight deficit
00:51:51.320
of formation of new memory is on some levels, not necessarily a pathological finding as we age,
00:51:57.960
but how do we differentiate between the pathologic or the appropriate age related versus the potentially,
00:52:05.000
you know, the harbinger of something pathologic?
00:52:06.840
It is difficult to draw the line. This is one of the main reasons that this diagnosis of mild
00:52:12.920
cognitive impairment has been elusive. I have asked this question to all the researchers
00:52:19.640
and I get very many different opinions. And the main reason is that the only way to know for sure
00:52:25.560
is to compare this to your own history, to compare it to yourself. So in this case, the patient and their
00:52:33.160
immediate patterns, they are more knowledgeable whether there being a change. If you just compare to
00:52:41.160
a standardized age population, you may not see any difference, but the patient will tell you,
00:52:48.280
no, I know I am having more difficulty with, for example, this working memory task.
00:52:54.200
So it is a challenge. But the beauty of this is you don't have to wait because everybody goes
00:53:01.960
through this cognitive decline. It's just to a different extent. And we all start out at a different
00:53:08.360
level of cognitive performance. So it's very difficult to have a standard. So my approach
00:53:15.560
is to try to intervene at that point. And therefore, the main target at that point is to intervene
00:53:22.600
in the prefrontal cortex, the region that is just behind your forehead. And that one engages,
00:53:30.360
we call it a central executive network that for cognitive processing that is involving working
00:53:38.040
memory, that is involving problem solving, that is involving sustained attention, vigilance.
00:53:44.120
Those are the things that you're going to be seeing first, having a decline as you grow older,
00:53:50.920
just like all kinds of tissues decline as you grow older. This is a reality.
00:53:57.240
But it is possible to intervene then before you get into the limbic system problems. And that's
00:54:03.880
the approach that we have done and in our interventions. And I think this is what's
00:54:09.240
going to make the biggest difference. So let's go back to now the sort of revised hypothesis. If I can
00:54:15.400
summarize, the actual nomenclature of Alzheimer's disease might be a bit of an unfortunate artifact in
00:54:21.880
that it was first observed in a subset of what would become this disease that really isn't
00:54:27.880
representative of the epidemic that we're seeing today. Absolutely right.
00:54:32.280
And so we'll put that aside for a moment because despite how tragic those early onset cases are,
00:54:38.040
and they strike me as among the most tragic things I've ever seen in medicine, by the way,
00:54:42.600
you have more experience with this. The thing that's running amok right now
00:54:46.440
now is this sort of late onset dementia that it seems to me that we are probably diagnosing it
00:54:54.520
much more than we were before, but it also seems to be increasing out beyond just the rate of
00:54:59.800
diagnosis. And it also seems to be increasing at a rate disproportionate to the increase in our
00:55:05.000
longevity, which is really not that significant. I believe that human longevity
00:55:09.000
longevity is increasing at about 0.4% per year in the United States. And yet the rate of
00:55:16.520
growth of Alzheimer's disease is growing much more than that. So if you discount that somewhat for the
00:55:21.880
rate of, for the diagnostic acumen or urgency with which we seek it, there's still a gap,
00:55:26.920
which means on a real level, not just a perceived level, this disease is becoming more common.
00:55:32.840
In your research, you talk about five areas of study that help you think about this. The
00:55:38.360
epidemiology of the disease, the imaging of the disease, the pharmacologic response to the
00:55:44.280
disease, the pathologic findings in the disease, and then the clinical course of the disease. You
00:55:51.000
and your colleagues have a different hypothesis that pertains to the vascular system. Yes. This is
00:55:56.760
actually the original hypothesis that was associated with senile dementia. I don't want to take credit for
00:56:04.760
for the people who have gone after that because in the early days it was just an idea, not well
00:56:10.520
formulated. But what seems to be happening is if you compromise circulation to the brain, you're
00:56:18.920
always going to get a neurological deficit. However, in the case of what we're seeing as late onset
00:56:25.160
dementia that I may refer to as features dementia as opposed to the early onset Alzheimer's dementia,
00:56:33.480
which is what should have been named, there is a chronic hyperperfusion. That is, the brain is
00:56:40.120
receiving less blood supply. And for example, it is known that between 22 years old to 60 years old,
00:56:51.080
there is a decrease of about 20 percent on your supply of blood to the brain. So some people have
00:56:58.680
calculated about approximately half of a percentage per year in statistical terms.
00:57:04.200
Do we have a sense of why? How much of that? I mean, because I think a lay person might understandably
00:57:10.760
but naively assume that is just due to a gradual and gradual narrowing of arteries or something like
00:57:17.000
that. But it strikes me that that's very unlikely the case and that it's much more related to something
00:57:22.920
within capillaries and or other metrics. Because paradoxically, as we age, we're seeing an increase
00:57:29.640
in our blood pressure typically. So when you're 20 versus 60, you're generally running with a higher
00:57:34.280
blood pressure. So if anything, you would think that should increase cerebral perfusion, not decrease
00:57:38.840
it. But of course, we're not seeing that. So what do you think at the level of vascular biology would
00:57:44.520
explain even that observation? Yes. Unfortunately, the answer is all of the above. In other words,
00:57:50.200
the vascular changes happen at the microscopic and microscopic levels. But it is the case if you,
00:57:57.960
for example, only look like we have done, for example, the carotid artery, the one in the neck
00:58:04.440
that supplies the blood to the head, this is where most of the blood is going to the brain from this.
00:58:11.160
And you can use ultrasound imaging non-invasively and are able to look at the layers. So even the
00:58:18.440
intimal thickening of the carotid artery, which would presumably get a little more and more and
00:58:23.640
more as one ages, is going to play a role in this potentially. Oh yes. There is a linear relationship
00:58:30.280
between what we call the intima media thickness, the layers of the artery and the decline in
00:58:38.920
cognitive function. Now why, I mean, this sounds silly, but why a linear relationship given that it
00:58:44.600
should be non-linear, shouldn't it? Given that with increase in intimal thickening,
00:58:49.960
you would see exponential change in diameter or in cross-sectional area. Wouldn't that lead
00:58:56.760
to a non-linear change in perfusion? No. Which I realize you were talking
00:59:01.000
about cognition, not perfusion. Cognition, not perfusion.
00:59:03.800
The reason there is not a linear change with perfusion is what you alluded to. We have an
00:59:09.800
auto-regulatory mechanism. I get it. That basically can start to auto-correct, at least
00:59:15.560
try to dampen it, dampens it from an exponential problem to a linear problem. That's a beautiful,
00:59:21.800
beautiful example of biology. So has the artery become stiffer with the thicker walls? It's just
00:59:28.120
like if you imagine somebody having a hose that is releasing water and then you stick your finger in
00:59:34.360
front of the hose and you can see how the water is coming in a faster place. So this is one aspect,
00:59:41.400
but this is the auto-regulation. The body is trying to achieve that. It does that when the walls become
00:59:48.200
stiffer because of the thickening. When you have this systolic pump that they're supposed to comply,
00:59:54.840
no arterial compliance, they don't do that. So even though you may see the lumen being the same size,
01:00:01.320
in other words, the hole being the same size, but it's not the same size when you have the pulse,
01:00:07.480
the bolus of blood going through that it has to open up. However, when we increase blood pressure,
01:00:14.440
we have a constant process of trying to increase blood pressure to maintain that same level of perfusion.
01:00:21.480
So the compensation for the macrovascular disease may actually be driving part of the damage at the
01:00:34.440
microvascular disease. Yeah. You're pushing now with a higher blood pressure through capillaries,
01:00:39.960
and this creates a pathology at this boundary we call the endothelial walls. And these endothelial walls
01:00:47.000
are now subjected to mechanical pressures that they were not designed to do. And you have extravasation,
01:00:54.520
and you have cells that normally are only engaged when we have like a hemorrhage, like the platelets
01:01:01.880
to try to coagulate. Now they start sticking to these endothelial walls and compromising some of the
01:01:08.840
microcirculation as a consequence. So the auto-regulation cannot compensate and it creates
01:01:18.040
additional problems as time goes by. And that's why you are actually better off with less blood pressure
01:01:25.880
by controlling your high blood pressure than with more, even though you're trying to make up for
01:01:32.120
the decreased blood supply. And this has actually been borne out in very recent clinical trials. Every
01:01:37.400
five years or so, we see more and more data revising how we think about blood pressure regulation.
01:01:44.040
And the most recent results seem to indicate the best outcomes occur with a systolic blood pressure
01:01:50.440
below 120 millimeters per mercury, a diastolic below 80. Formerly, this used to be 135-ish,
01:01:58.600
over 90 was accepted. So that's a significant difference because many people walk around,
01:02:05.560
many adults walk around with a blood pressure above 120 over 80.
01:02:08.920
You're right. And that is an index of this pathology that is developing in the large arteries,
01:02:16.840
like in the carotid here. But I'm using the carotid as an example. When this happens at the level of
01:02:21.720
the carotid... You know it's happening up to vertebral arteries and into the circle of Willis and the main...
01:02:27.880
Basically, it's happening more in the arteries that have the largest flow, because we get like about
01:02:34.520
one-third of the blood going into the head, primarily for the brain function. So there is a much more
01:02:42.360
blood flow that is going through those arteries than the one, for example, going through your arm,
01:02:48.200
your brachial artery. However, in the case of the heart, the same thing happens. You have the small
01:02:53.960
coronary arteries that are feeding the heart itself as soon as it pumps. So they have greater flows.
01:03:01.800
And the other thing that happens, these walls are not only thicker, but they become irregular,
01:03:07.640
especially the inner walls are no longer smooth. And when they're no longer smooth, you start creating
01:03:15.480
turbulence. That is, if you look at the flow of liquid, when they hit an irregularity in the
01:03:22.360
walls, there is a little turbulence. So this turbulence creates a system in which deposition
01:03:29.080
is going to be favored, like when blood is going. Or in the blood, it's usually the white blood cells.
01:03:36.840
Is it usually a macrophage that infiltrates as well?
01:03:39.480
Yes. But even before infiltrating, they identify this area of turbulence as an area of injury.
01:03:46.840
And they start aggregating there. And because of the turbulent cells, they start then dying out
01:03:54.520
against the walls. And unfortunately, cholesterol levels then can add to it. But they are not the
01:04:02.200
problem. The high total cholesterol is not the reason. Again, they're confusing causality here
01:04:09.960
with a consequence of this problem. So lowering your total cholesterol is not going to really
01:04:16.520
make a major difference in this progression, which is, I think, one of the biggest misconceptions
01:04:22.840
that is happening in medicine right now. But in any case, you have a number of phenomena that are
01:04:29.480
taking place that are contributing to the vascular hypoperfusion. On the other hand,
01:04:36.360
you can have a similar type of insult to the brain not coming from this atherosclerotic process.
01:04:44.840
If the heart muscle itself is compromised in its function because of a process where it weakens
01:04:52.600
its ability to operate as a pump, you're going to have hypoperfusion that is going to be developing.
01:05:00.040
And in that case, there would even be less likely that you're going to have an
01:05:03.720
auto-regulatory mechanism for that. So you can have heart disease that is affecting the pumping,
01:05:11.080
you know, the force of the pump that can lead to the hypoperfusion. You can have arterial disease
01:05:18.520
like arteriosclerosis that is causing similar kind of phenomenon with some more complications
01:05:24.600
that are detected by this high blood pressure. In the cardiac case, you will not see the high blood
01:05:30.040
pressure, but in the other one, you will see that. And so all of these things can be detected.
01:05:35.160
It is possible for cardiologists to advance and measure these things. And once you detect this,
01:05:42.040
the health of the heart and the arterial circulation in particular is very closely related to the health
01:05:49.400
of the brain. So if whatever you do that improves cardiovascular health will also help the brain.
01:05:57.480
But there are some differences. For example, the brain in some ways seems a little bit more exposed
01:06:03.800
because the brain is perfused during systole at a higher pressure. The heart is the only organ that
01:06:11.320
is actually perfused during diastole. So in that sense, the coronary arteries themselves are less
01:06:18.600
susceptible to hypertension than the arteries in the brain or the kidney for that matter, which would be the
01:06:23.960
two organs that seem to be most damaged by hypertension, more so than the heart.
01:06:29.160
The other thing that I'm hearing you say that creates a bit of a differentiation between the heart is,
01:06:35.480
you know, in the process of atherosclerosis in the heart, cholesterol does play a very important role.
01:06:40.680
But so you still have the initiation of the endothelial injury, which is necessary.
01:06:46.040
But once the lipoprotein can get inside the subendothelial space and becomes oxidized,
01:06:51.240
that's what elicits the immune response, which is what does the damage. What you're describing
01:06:55.960
in the brain is two different processes, if I'm hearing you correctly. The first is
01:07:00.200
cerebrovascular disease that leads to strokes, occlusive or hemorrhagic, which that's a separate
01:07:07.640
disease because it tends to produce an acute event that is the result of an acute hypoperfusion
01:07:14.280
that usually produces a much more functional deficit. So it's almost like you can think of
01:07:18.440
that as a quote unquote brain attack, the way we think of a heart attack.
01:07:22.360
But what you're describing that is now sort of unique to me is a different type of much more
01:07:28.520
indolent chronic hypoperfusion that actually seems to have a slightly different pathophysiology
01:07:33.960
from coronary physiology that doesn't produce an acute event, but rather a chronic disease.
01:07:41.720
You summarize that really well. It is this chronic brain hypoperfusion, regardless of the
01:07:48.360
particular cardiovascular cause, because I told you with heart failure, you can have,
01:07:54.680
you can simulate that aspect, but without some of the other components.
01:07:58.840
So it is possible nowadays to pick this up and to intervene, to try to resolve these vascular
01:08:06.920
problems or cardiovascular, they involve the heart.
01:08:10.440
So the epidemiology states the first and most obvious relationship, which is so obvious that
01:08:16.440
it's not almost not helpful, which is there is no greater association with Alzheimer's disease than
01:08:21.320
age, just as there is no greater association with cardiovascular disease than age. So that's stating
01:08:28.120
the obvious, but it's very difficult to draw a clear hypothesis or at least confirm a hypothesis.
01:08:34.600
So the next layer of thinking on the epidemiology is what? Is it the association with hypertension
01:08:41.560
or is it the association with cardiometabolic disease? How do you then continue down that
01:08:47.240
line of thinking on from just, just again, before we get to the more interesting stuff,
01:08:50.920
which I think is the pathology and the pharmacology, just based on the epidemiology,
01:08:55.800
What would be ideal to me would be what is the main purpose of that circulation from the point
01:09:04.120
of view of energy is to bring oxygen to the tissue, tissue oxygenation. It is only through this process
01:09:14.200
of reducing oxygen to water that in mitochondria, this process is linked,
01:09:23.080
the cellular respiration is linked to the production of chemical energy.
01:09:27.720
So the more direct measurements would be measurements of oxygen consumption,
01:09:33.880
but also could be the enzyme that is responsible for that oxygen consumption.
01:09:40.680
And that's where it comes to our work. And what we found in the brains of those Alzheimer's patients,
01:09:46.040
we found that the enzyme calls cytochrome oxidase or cytochrome C oxidase.
01:09:50.680
Which is complex four in the electron transport chain.
01:09:53.640
The electron transport is the, the last rate, the last and the rate limiting enzyme
01:09:58.920
and the one that actually reduces oxygen to water that is linked to oxidative phosphorylation,
01:10:07.880
Let's pause for a moment to make sure people understand this. It's
01:10:10.680
so important that even though I think I've talked about this before, it's worth reiterating.
01:10:15.160
The mitochondria has an inner and outer membrane, and these have four complexes. Three of them span
01:10:21.480
both the inner and outer membrane. I believe it's one, three, and four. Complex two is only on the inner
01:10:26.120
membrane. These things are about the most essential elements of life. Interrupting their activity for
01:10:36.120
I would say it's the key to aerobic life on the planet.
01:10:40.520
Yeah. You can't overstate the importance of the electron transport chain.
01:10:46.520
As you pointed out, it is basically, you know, we can't create energy out of nothing. We simply
01:10:52.440
change its form. And so when we eat food, we're eating stored potential energy that is in a chemical
01:10:58.920
form that is generally between the carbon-carbon, carbon-hydrogen bonds. As these things get reduced
01:11:04.520
to simpler and simpler molecules, this process specifically within the mitochondria takes
01:11:11.560
these units and it, by breaking apart the chemical bonds, creates an electrical gradient by shuttling
01:11:19.880
electrons outside of this membrane as they go from complex one, two, three. And of course, they each
01:11:24.760
come with their own reducing agents. I spend my most time thinking about complex one, which is the NADH,
01:11:29.960
NAD shuttle. But I believe complex four is NADPH, isn't it? Is that what it's using as the electron
01:11:35.240
acceptor donor? Yes. I need to emphasize from what you're saying so people understand. The whole purpose
01:11:41.800
of that chemistry that is done with the foods that we eat is to generate electron donors. Electron donors
01:11:49.800
are going to donate their electrons to the electron transport. And there are only two of them,
01:11:56.440
the NADH and the FADH. And the NADH primarily, it donates to different parts of the electron
01:12:05.320
transport systems, but the other one, the FADH only to complex two. So you have like two entry points,
01:12:12.040
complex one and two, and then... And that's why complex two doesn't span the full membrane. It's
01:12:16.760
sort of sitting there only on the internal. And it's much smaller than complex one is the largest one.
01:12:20.920
So this is a key. This is a biochemical key to this phenomenon because what we eat from an energy
01:12:27.800
point of view is just becoming electron donors. So it's, can we donate electrons to the electron
01:12:33.800
transport? If we could do that, we can accelerate respiration because the ultimate electron as sector
01:12:40.760
in nature is oxygen. And that's what we call oxidation, the process of removing electrons.
01:12:46.040
And so making water out of oxygen and these protons that are being donated is the ultimate
01:12:54.760
byproduct of respiration. That's why we breathe out water vapor. And of course, all of this is in
01:13:00.440
service of creating an electron gradient to then fuel the generation of adenosine triphosphate ATP.
01:13:08.440
Yes, what the mitochondria have done is coupling this affinity of oxygen to take these electrons that are
01:13:16.680
coming from the food that we eat into a closed system in which the electrons, when they are moving from
01:13:28.920
one complex to the other, they are releasing what is called a proton that is positively charged. And this
01:13:37.320
is trapped in that intermembrane between the two membranes that you mentioned, the outer and the inner
01:13:41.880
one. And the matrix of the mitochondria, the more innermost portion is primarily negative in electrical
01:13:52.200
charge. Ions are negative. So these protons are trying to move. They are attracted towards this
01:14:01.640
negativity, just like when you have the poles in a magnet, the positive and the negative poles. This
01:14:07.880
is what we call electromotive force. There are only very few forces in nature, like gravitation,
01:14:14.280
and this one is electromotive force. So the system was designed in such a way that the protons will
01:14:20.280
leak through a hole. And that hole or pore is this complex five. And complex five is designed so that when
01:14:30.360
the proton is pushing through to get from the inner, excuse me, from the inter membrane space to the
01:14:39.480
matrix, it clicks, changes the conformation of that enzyme. And that movement generates the energy for
01:14:48.760
a phosphate to be bound to ADP. And that phosphate is called inorganic phosphate. When this is what in
01:14:56.120
chemistry is called an endothermic reaction, it needs energy in order to happen. And it's because of
01:15:02.680
that movement. And then later on, when you need some other enzyme to work, all of these chemical
01:15:09.880
reactions that have to do with life are catalyzed or mediated by enzymes. What this means is that
01:15:16.120
you may have the reactants already in place, but nothing is going to happen in terms of products,
01:15:22.200
unless you provide energy to the system. So these are so-called reactions that when you remove that
01:15:30.440
phosphate from the ATP, it generates heat. And this is what we call calorie. And you can then have a
01:15:40.200
relationship, a quantitative relationship with how much food you eat, how many electrons are donated,
01:15:45.800
how many of these phosphates can be broken and generate that heat. And that heat is just like in
01:15:51.160
chemistry, when you add your reactants in a beaker and you have a catalyst and nothing was happening.
01:15:57.560
And then you apply heat and then all the resulting reaction happens, it changes color, for example.
01:16:03.000
And when that phenomenon happens, then we call that an exothermic reaction that break it and it fuels.
01:16:12.200
So the key to the system is to be able, how can we facilitate that mitochondrial respiration?
01:16:18.120
And this illustrates, of course, the most important point here. What you're saying is
01:16:23.400
the whole purpose of eating is to convert chemical energy into chemical energy from one form to another.
01:16:29.480
But to do it, you need an intermediary to translate. And that intermediate has to turn the chemical energy
01:16:35.720
into electrical energy that then facilitates a conversion back to chemical energy. That is the key
01:16:41.240
to life. Yes. And that is what the mitochondria do. However, there is a way, at least aerobically,
01:16:46.760
we can obviously do this inefficiently and anaerobically later, but yeah. Correct. Correct. You can do this,
01:16:52.520
especially in other tissues, not so much the brain. You can generate ATP without using oxygen and this machinery.
01:17:00.520
But every organism, including single cells on the planet that uses oxygen to obtain energy relies
01:17:08.680
on cytochrome oxidase. They may not have mitochondria, but at least they need cytochrome
01:17:13.480
oxygen. Wait, I didn't realize that. So red blood cells, for example, don't have mitochondria. Do they
01:17:17.560
have cytochrome oxidase? Yes. Yes. I didn't know that. Yes. If they use oxygen to generate ATP,
01:17:24.760
they have to have cytochrome C and cytochrome C oxidase. This is the minimum requirement. That's why
01:17:32.280
you can look at cell lines from microbes and so on, and you can identify these proteins. As long as it's
01:17:39.000
aerobic, it's the only way nature found how to solve this. But the interesting thing is that when the
01:17:46.760
circulation is compromised, then you have less oxygen. You're creating a situation where these
01:17:53.080
events cannot move on. It doesn't matter how much you eat, and this is happening in older people,
01:17:59.000
it doesn't matter how much they eat. In fact, their brain is telling them that they should be hungry
01:18:04.360
because they are not able to transfer those electron donors into electron transport and produce energy.
01:18:11.800
So they feel they're energy deprived. So they increase food consumption, especially they are attracted to
01:18:17.960
carbohydrates. Simple carbohydrates that can quickly break down and produce these electron donors.
01:18:23.320
So do you think that this is the first insult then? Because you talked about this slightly
01:18:29.000
different type of microvascular disease that is much more chronic and insidious and doesn't lead to
01:18:33.720
acute changes like hemorrhage or occlusion. How does that change ultimately impact the ability of the
01:18:41.880
mitochondria to do its job and facilitate electron transfer? Yes, you put your finger on it. This is
01:18:48.440
what links this phenomena. Regardless of whether the chronic hyperperfusion or the more acute,
01:18:54.360
one of the things that happen is when we have a hypoxia situation, cytochromoxidase is an inducible
01:19:02.440
enzyme. What that means is that our body only maintains
01:19:07.640
as much as it's needed, as much as it's demanded. It's a complex of 13 different subunits,
01:19:14.440
three of them mitochondrial DNA derived and the other 10 from nuclear DNA. And you can regulate it
01:19:21.240
at many different levels, including both the nucleus or mitochondria. But essentially, within minutes,
01:19:28.600
if, for example, you have an area of ischemia, you occlude the blood vessel,
01:19:32.600
half an hour later, you lost a significant amount of cytochromoxidase from being functional.
01:19:38.360
And that's irreversible then? No, it is not irreversible. That's the the advantage of the
01:19:44.200
system. The system works on demand. It may not be immediately reversible, depends on on the level
01:19:50.760
of regulation. In other words, you can simply inhibit the enzyme and the enzyme is still there.
01:19:56.440
Or you can disassemble the catalytic units of the enzyme, the ones from mitochondrial origin,
01:20:03.640
and then you have a partial enzyme, not the so-called hollow enzyme. Or you can eliminate
01:20:10.120
the other components. And throughout the mitochondrial inner membrane, you have all of these gradations
01:20:15.720
of stages that can be used for regulating this. So you can regulate it in a more immediate way,
01:20:20.520
or eventually you need proteins transported from the cytoplasm to be chipped where the mitochondria are
01:20:29.320
and incorporated into this. Why was this done? Because mitochondria have a symbiotic relationship
01:20:36.920
with the cells that they live on. And this was created to develop a dependency that mitochondria are
01:20:44.840
doing this, but they cannot do it on their own. The cell has found a way to obtain the energy,
01:20:52.360
but it's conditional on then contributing a component that is necessary for the entire machinery to work.
01:21:00.040
The important portion here is that these phenomena are coupled. As soon as you have hypoxia,
01:21:06.680
ischemia you reduce, then this machinery goes down-regulated. Is that true of complex one,
01:21:13.320
two, three as well? Are they also inducible the way complex four is? Not as much as complex four.
01:21:19.400
They are, to a certain degree, if you keep taxing the system, it's going to happen. But the one that has
01:21:25.320
the more flexibility from more immediate to long term, because of this role as rate limiting,
01:21:32.360
is complex four. And that's the reason it is preferred modulator of the system.
01:21:38.200
That's why I love doing these podcasts. Every single podcast, I get to learn something new in
01:21:43.000
biology that I didn't know. I had no idea that complex four was inducible to a greater extent than
01:21:49.800
the others. As it is, for example, you may have heard for sure during your training about other
01:21:56.520
inducible enzymes, the cytochrome systems in the liver. P450, the most inducible of them all.
01:22:04.840
So it's a perfect example. If you drink more alcohol, you're going to build up more of these
01:22:11.320
cytochrome enzymes. So these are the most inducible enzymatic complexes that we have.
01:22:16.120
Just never think of it in something so important. Not that the liver is less important, of course,
01:22:20.680
but the ETC is so fundamental for everything that we do. It's so interesting to think of that.
01:22:28.200
And it's also interesting to hear you say that at least in transient periods of ischemia,
01:22:32.200
this is not irreversible. No, it's not irreversible. It's an inducible system,
01:22:36.120
just like you stop drinking alcohol. These enzymes are going to be down-regulated,
01:22:42.200
but if you start challenging the system again, they are inducible. They're going to go back.
01:22:47.400
Of course, you're going to suffer somewhat in between because at the beginning, you're not
01:22:51.640
going to be able to meet the demand, but they are inducible. And this is the key that I have
01:22:58.280
understood from our investigation of the Alzheimer's brain. In those fresh frozen Alzheimer's brain,
01:23:04.760
the main problem was cytochrome oxidase inhibition. The levels of the protein levels of the enzymes were
01:23:12.280
not compromised, but you could see that the enzyme was not in its catalytic functional state. And you
01:23:20.120
could demonstrate this doing enzyme histochemistry. If you were able to extract at the moment those
01:23:26.920
patients died their cells in culture, and now they're perfused, would they have still been hypo
01:23:34.840
functioning? In other words, would you still have been able to measure a deficit of oxygen utilization?
01:23:39.160
Yes. Yes. And this has been done. Groups have taken, actually what they've taken is mitochondria,
01:23:46.040
and they can then see that these mitochondrias are not performing this cellular respiration from
01:23:52.360
Alzheimer's patients. Give me a sense of what is the magnitude of the deficit to result in the
01:23:58.200
phenotype that we observe clinically? Yes. This is a very good question because if you inhibit
01:24:04.040
cytochrome oxidase, after about 40% in an organism, the organism dies. You cannot cut. This is as a...
01:24:15.560
But presumably it's a nomogram of duration and degree of suppression, right? So maybe you could
01:24:20.280
have a 40% reduction for two seconds, but not a 40% reduction for two minutes or something.
01:24:26.760
I mean, I assume that there's... That's correct. That's correct. For example,
01:24:29.800
the classic poison, cyanide. Cyanide. Okay. What does cyanide do? Cyanide is complex for a
01:24:38.040
cytochrome oxidase inhibitor. It gets into the circulation, it inhibits cytochrome oxidase,
01:24:44.280
and minutes later you die. So if that happens, it's not compatible to life. However, you can have many
01:24:52.360
degrees of this reduction because the enzyme is so inducible, you not only change the catalytic
01:24:59.080
activity of a particular... In other words, cyanide is not binary in its ability to kill.
01:25:04.040
It seems functionally binary because it's so potent that even a trace amount of cyanide will
01:25:09.000
kill. But presumably, if you dilute it enough and enough and enough, you could give enough
01:25:12.760
cyanide to somebody that they have a chronic illness due to... It's almost like it's a thought
01:25:17.640
experiment. You could induce Alzheimer's at a low enough dose of cyanide to create a functional
01:25:23.560
hypoperfusion by inhibiting complex four without killing the organism. And we did this. I like when
01:25:29.240
I think of things 10 years after someone else did it. This thought experiment was done. And in fact,
01:25:34.120
Dr. Jack De La Torre, the one that wrote the book, Alzheimer's Turning Point, that I highly recommend.
01:25:40.840
Yeah. We'll link to that for sure. And we collaborated in that study. So it works both ways. In other
01:25:46.920
words, if you compromise the circulation by partially occluding blood vessels to the brain,
01:25:53.560
you get a downregulation of cytochromoxidase, and therefore, mitochondrial respiration and
01:25:58.840
ATP production and so on. And the animals show a cognitive picture that is analogous. It's not the
01:26:05.800
same, but it's analogous to what you see in cognitive, neurocognitive disorders. And the other way
01:26:12.840
around, you can directly suppress the electron transport. And in our study, we decided to use
01:26:19.560
sodium acide because it's less potent than cyanide. And when you do that, yes, you have an animal that
01:26:27.480
at a very low level of decreasing, you can decrease up to 30% without seeing any neurological
01:26:35.720
evidence change. The animals appear to be eating and behaving normally. But when you test them with
01:26:41.960
cognitive memory tests, they cannot perform well. In other words, a 30% reduction in the oxidative
01:26:49.080
capacity of complex four shows cognitive impairment when challenged, even though behaviorally at the
01:26:56.520
gross motor level, the animal is still fine. Just like an Alzheimer's patient that you will appear,
01:27:02.280
they will appear to be generally okay. Until you test the system harder. Yes.
01:27:06.840
Yes. So these animals, and in fact, that was proposed as a model for Alzheimer's disease,
01:27:11.960
that very same approach by colleagues of mine. The one that comes to mind is Rose Bennett,
01:27:18.200
Rose and Bennett. However, because of the influence of these amyloid and tangles hypothesis,
01:27:24.760
all of these models were based on biochemical and physiological phenomena were really not developed
01:27:31.400
fully. All the attention was in the genes and the normal proteins. But yes, you can do this in
01:27:39.000
animals. You can test these hypotheses in animals. And does this lead to any change in the amount,
01:27:45.400
let's assume you had an animal model where you could do this for a long enough period of time before
01:27:49.000
the animal would die. And you had a control animal in which it was, you were not doing this. Would you,
01:27:54.760
in those two situations side by side, see a difference in amyloid beta accumulation?
01:27:59.080
No. The amyloid beta will not be a good reflection of these processes. The amyloid beta is primarily
01:28:07.000
a process that is compensatory when the cells are showing atrophy. So when cells start showing signs
01:28:14.040
of atrophy, we have a lot of amyloid beta that is released embryonically during the development of
01:28:20.840
the nervous system. And it's because during development of the nervous system, you have
01:28:25.880
phases of a large proliferation of neurons, but then you have other phases of trimming where there is
01:28:34.200
a lot of neuronal death. And in those situations that you see amyloid that is formed. So as you know,
01:28:43.560
probably the major signal for a cell to die in an aerobic organism is for the mitochondria to release
01:28:54.120
cytochrome C. Cytochrome C is the protein that carries the electron to cytochrome C oxidase. If
01:29:00.920
that machinery is not working and cytochrome C leaks out, we say the mitochondrial permeability
01:29:08.040
pore has been modified so that small cytochrome C leaks out. That's a big signal for apoptosis.
01:29:15.320
Apoptosis or programmed cell death. In other words, if a cell mitochondria...
01:29:19.880
That's the surrender of the cell. That's the white flag. Here's my cytochrome C.
01:29:23.960
So what I'm telling you is if you compromise the system, you're going to have neurodegeneration.
01:29:29.720
You're going to have cell death. And not just in the nervous system. It just happens that there
01:29:33.960
is more critical because in all the systems, we have all the ways to get ATP. But in neurons,
01:29:39.560
we don't have any significant amount of alternative ways to get it.
01:29:43.320
Yeah. That's exactly the point I was going to make is we're having this discussion
01:29:47.320
and it would be easy for a moment to say, wow, why is this all isolated to the brain? It's not. It's
01:29:53.000
just the brain, I think, has two problems. The first, you know, if you're going to be critical of
01:29:58.760
the brain, the first is an energetic problem, which is, it is simply the most demanding and
01:30:04.760
therefore it is the most susceptible to a reduction in total available energy. The brain weighs about
01:30:11.160
2% of our body weight and yet consumes about 20% of our total energy expenditure. So that's a
01:30:17.800
grossly disproportionate amount of energy. And the second, by the way, would be the kidney,
01:30:22.920
which by the way, is the second organ we tend to see great ischemic. When we see hypoperfusion
01:30:29.320
clinically, we see kidney damage and myocardial damage. So the more energy demanding the organ,
01:30:35.080
the bigger the problem. And then the second issue with the brain is this seemingly over-reliance on
01:30:40.680
oxidative phosphorylation without an anaerobic escape route. Yes, you are right on target. And this is
01:30:47.160
what makes it so vulnerable. And this is why we see these changes more as cognitive deficit
01:30:54.360
before all the tissues are really damaged or the brain itself. But as you continue with this process,
01:31:00.440
as we just talked about, if downregulation of cytochromal oxidase reaches a certain level,
01:31:06.520
cytochrome C is going to start releasing. There is this permeability change goes out and cells start
01:31:12.920
dying. So it is the the direction of causality is completely different from the amyloid ideas that
01:31:20.760
the amyloid comes there because of the gene that is abnormal. And then it's creating these cascades
01:31:26.840
that are leading to these changes. No, what we have is these problems with supply of oxygen
01:31:34.040
that happen to the brain and it's high energetic demand. And they could be due to the circulation
01:31:40.920
or it could be due to a cardiac effect on the circulation. But unfortunately, the vascular
01:31:47.640
hypothesis of dementia is not exclusionary because you can have toxic insults that affect the mitochondria
01:31:56.440
that will, for all physiological purposes, will do something similar to these cardiovascular insults.
01:32:04.200
In other words, they're going to lead also to downregulation of cytochromal oxidase and your
01:32:09.560
inability to use oxygen to generate energy. So that's why I have used that entry point into
01:32:17.320
the system because it is completely consistent with the vascular hypothesis of dementia, but it also
01:32:25.000
provides room for other insults to the brain that are going to be reflected at that level. And it's
01:32:32.920
only when they're reflected at the level that then they, because of this energetic demand,
01:32:37.160
this vulnerability that you alluded to, that then this is going to lead to a cognitive. Why a cognitive
01:32:43.080
problem and not something else? Because when we are engaged in these functions that I explained,
01:32:51.880
we, these functions are not limited to one region of the brain. They are relied on interaction between
01:32:59.080
different regions. So when you're reading something, that information goes to your visual system. But then
01:33:05.320
if you're going to engage learning having to do with that, that will engage other systems. So
01:33:10.840
the memory functions are more distributed. So when you have a more distributed metabolic insult,
01:33:17.400
they're going to be affected. It's just like people know somebody may get a blow to the head
01:33:23.080
and then all of a sudden they may have retrograde amnesia. They may not remember what happened. They may
01:33:29.080
not even remember who they are. And you may not see any significant level of structural or functional damage,
01:33:36.120
but you affected the way the systems were interacted in a more global way. So this is one of the reasons
01:33:43.080
we detect this primarily as a memory problem initially. But later on, it becomes a neurodegenerative disorder
01:33:50.280
when cells cannot longer work without this mitochondrial machinery.
01:33:55.080
Do we have any insight into how much mitophagy or autophagy is going on in the later stages of
01:34:03.160
Alzheimer's disease? In other words, is it possible that so much of this damage is now due to defective
01:34:09.800
cleaning up of the mitochondria? Because the more these mitochondria are damaged, the more mitochondrial
01:34:16.120
DNA is getting released. The mitochondrial DNA itself is actually looks bacterial. So it elicits an immune
01:34:22.200
response. This probably accelerates the process. It would seem that anything that would increase
01:34:28.200
mitophagy or autophagy would at least be able to curb the progression of the feed forward loop on this
01:34:36.200
damage going and accelerating. Wouldn't that make sense? Yes. I agree. However, it's too late. If you
01:34:43.880
already compromise the machinity for obtaining the energy, it's too late at that point. So my focus on the
01:34:51.480
focus of Jack De La Torre and other people is how can we intervene? For example, one way is in the
01:34:59.160
risk factors that have to do with the cardiovascular compromise. Try to intervene with the risk factors.
01:35:04.680
Besides blood pressure, what do you view as the most important risk factors then?
01:35:10.120
I think atherosclerosis is a really important risk factor. And the major blood vessels you indicated,
01:35:17.960
like the carotid, the ascending aorta, and the renal arteries, they are the large blood vessels are
01:35:25.880
the main targets of these atherosclerotic processes, especially at the bifurcation points.
01:35:32.280
The other factors that I would consider would be generalized trauma to the brain.
01:35:38.760
Yeah. I was going to ask you about this. This seems to bear an uncanny resemblance to
01:35:45.240
chronic traumatic encephalopathy, where the difference is if you're a football player or a
01:35:50.440
boxer, you have repeated short bouts of hypoxia. It appears from my reading of the literature that
01:35:57.400
every time you're getting hit in the head, you're having a transient interruption of blood flow. And
01:36:04.280
also it appears based on at least the animal models, we're seeing transient insulin resistance
01:36:10.040
at the level of pyruvate dehydrogenase. So a blow to the head will transiently make it harder for
01:36:16.920
pyruvate to turn into acetyl-CoA, which is the opening substrate in the Krebs cycle.
01:36:23.640
The Krebs cycle. And so while the patients we're describing, who presumably let's just make
01:36:29.080
math simple and say they never get a concussion or a hit in the head, they have this chronic insidious
01:36:35.080
disease process. The athletes who are suffering this type of injury are getting punctuated by spike
01:36:40.840
functions of these, and it doesn't have to be a concussion every time. It could be each play on the
01:36:46.520
Do you think there's an overlap in these processes?
01:36:48.360
Oh yes, completely. This is what's called dementia pugilistica originally. And often
01:36:56.360
nowadays this is confused with Alzheimer's disease and Parkinson's disease. In the case of Parkinson's,
01:37:02.520
is because with the blows to the head, there is a rapid twisting of the head. When you get a blow to
01:37:09.320
the head, a rapid twisting, bending of the head with respect to the neck.
01:37:14.040
Yeah, it's an angular momentum that usually causes that injury.
01:37:17.880
And this affects the midbrain and the upper brain stem. And actually that's what leads to the knockout.
01:37:24.440
That would feed more into a Parkinsonian phenotype in the midbrain and the substantia nigra.
01:37:30.760
Isolating that region is more vulnerable for this. But it is the same phenomenon. All of these forms of
01:37:36.600
dementia will have a common denominator at some point, regardless of the many different ways that you
01:37:43.160
can impact the system. The most likely common denominator would be at the level of the mitochondrial
01:37:48.760
respiration. And therefore, another way, for example, the circulation may not be a good target
01:37:55.320
for neurotrauma. But if you find a way to facilitate mitochondrial respiration, even if there is compromise,
01:38:05.880
hyperperfusion or some other condition. And this is what I've been working on for many years.
01:38:12.360
And once we discovered that the main problem in the Alzheimer's brain had to do with this
01:38:19.800
inhibition of cytochrome oxidase, we set out to how can we intervene? Is there any way?
01:38:26.040
And you have two interventions that you have now coupled that both work on cytochrome C,
01:38:34.200
Yes. Cytochrome C oxidase. Cytochrome C is the carrier and cytochrome C oxidase is the large
01:38:39.960
enzyme. The large complex. Yeah. Thank you for clarifying.
01:38:42.200
So the first one, I use a pharmacological approach because I was more familiar with those approaches,
01:38:48.040
but I couldn't do it with regular. Most of what is called neuropharmacology or psychopharmacology
01:38:54.680
is really aimed at neurotransmission, resectors and agonies and antagonists. What's needed here is
01:39:02.340
something is acting at the level of mitochondrial respiration. And reviewing all literature from the
01:39:08.260
1960s, I found out that methylene blue, commonly used compounds in the lab, was able to act as an
01:39:17.940
electron donor. And depending on the conditions, but if you make it in a very low concentration,
01:39:24.340
it acts as an electron cycler. It will donate, but it will also get electrons from other compounds,
01:39:30.020
and it will continue to feed into the electron transport as an alternate route. And in fact,
01:39:37.780
if you block, for example, complex one with rotenone that you're interested, still the electron
01:39:44.740
transport can proceed going through methylene blue as a bypass. Because in a normal organism,
01:39:51.780
complete blocking of complex one would be fatal. You're saying with a high enough concentration of
01:39:56.340
methylene blue, you can still get electrons past the bottleneck of complex one.
01:40:02.420
We can prevent in animal models degeneration. We've shown this in many preparations. We first
01:40:09.140
did it in the retina because it was more accessible and we could manipulate that locally as a model of
01:40:14.660
the brain. And then we did it in the brain. So this has an interesting history, right? There's a guy
01:40:19.380
named Paul Ehrlich who studied this, right? And the only reason I remember this is-
01:40:25.460
Really? Yeah. Well, I read something that I love where expressions come from. And so there's an
01:40:31.380
expression, balls to the wall, which means like going very, very fast all out. And most people
01:40:36.820
don't realize, but it just refers to a governor and a train where the governor, the faster that the
01:40:41.700
train was going, these balls that were hanging on, basically cables would move further and further out
01:40:47.300
as the centrifugal force goes. And once they touch the wall, that's the mechanism that would regulate
01:40:51.700
the speed and slow it down. But there's another expression that comes from Ehrlich's work, which is,
01:40:57.460
Magic bullet. And he referred to methylene blue as a magic bullet. And Ehrlich, Paul Ehrlich,
01:41:03.700
he worked in Berlin, Berlin, Germany. And he was able to be part of a very progressive group at the time.
01:41:12.260
And- This was before World War II. This was in the-
01:41:19.860
Yeah. 1886, he was working on this and he injected. At that time, it was the beginning
01:41:25.300
of the Industrial Revolution. And the first thing in the Industrial Revolution that was developed
01:41:29.540
were the textiles, being able to manufacture clothing. And one of the important things was the
01:41:35.380
transition from using natural products for dyes to develop chemists developing synthetic dyes.
01:41:43.300
And actually, Germany led this process and methylene blue was one of these synthetic dyes,
01:41:49.060
blue dye. And for many decades, it was the blue dye used in blue jeans and most of the other blue
01:41:56.500
clothing. So one of the things that intrigued Paul Ehrlich was that he injected methylene blue,
01:42:04.580
one of these neosynthetic dyes, into a live rat. And then he dissected the animal. After killing
01:42:13.300
the animal, he dissected the animal. And he found out that the methylene blue, this was a large
01:42:19.460
concentration intravenous injection, was primarily staining nervous tissue, the brain and peripheral
01:42:27.540
nervous tissue. So he created the concept there of a magic bullet. This is a chemical that, remember
01:42:36.260
this in the 1880s, this is a chemical that I'm giving systemically, yet it is somehow finding its way
01:42:44.500
to the nervous system. And it's becoming trapped there, as you can see by the stain. Later, this phenomenon
01:42:51.940
was called supravital or vital staining. And it was exploited, for example, by Santiago Ramón y Cajal,
01:42:59.940
one of my other heroes during this time. He referred to this as the Ehrlich reaction,
01:43:06.420
to be able to stain nervous tissue when the animal was alive. But what does it mean, the animal being
01:43:11.780
alive? The animal respiring, the animal using oxygen. So methylene blue, they didn't know this,
01:43:19.380
but methylene blue has affinity for these redox reactions that are happening in a maximized way
01:43:26.420
inside the mitochondrial in the electron transport chain. And especially at low concentrations,
01:43:32.820
it becomes trapped for periods of hours inside mitochondrial. It can work as a mitochondrial stain.
01:43:39.620
Does it become toxic? What does the toxicity look like at a higher dose?
01:43:43.460
At a higher dose, instead of acting as an electron cycler, it actually replaces oxygen in the,
01:43:51.140
you know, it competes with oxygen. Remember that I told you oxygen was the one that was taking the
01:43:56.020
electrons. So he can be, you wanted to have it in a low concentration that is giving electrons and
01:44:04.260
taking electrons at the same rate. But you're saying at a higher dose, it becomes a proton acceptor.
01:44:09.300
A little, yes, because it competes with oxygen and it oxidizes the tissues. And actually,
01:44:16.900
that was in part the first application that Ehrlich found for methylene blue.
01:44:23.140
So that's interesting because the only time obviously that
01:44:26.500
I've ever seen it used is for treating methemoglobinemia in the emergency room. So
01:44:30.980
someone is exposed to carbon monoxide, you know, acutely or even chronically over a long
01:44:35.860
enough period of time, this basically breaks it apart. So there you actually want it to
01:44:41.700
sort of out-compete oxygen a little bit, right? Is that what's happening there?
01:44:45.460
Yes, yes. No, what is happening there in the carbon monoxide occupies the, in the heme molecule,
01:44:51.540
the pocket where normally oxygen finds. That's right. So you actually wanted to-
01:44:55.460
A competitor. Yeah. You wanted to get the carbon monoxide out.
01:44:59.220
That will displace it. And methylene blue will do that. But because you do this infusion,
01:45:05.860
so methylene blue can be used to prevent or rescue you from methemoglobinemia,
01:45:15.300
this inability to bind the oxygen. But a higher concentration induces methemoglobinemia.
01:45:22.740
Yes. The same compound. So this is typical of all of these redox chemicals that I studied. They
01:45:30.100
have this- They have bimodal functional points.
01:45:32.420
Yes. We call this biphasic dose response or hormetic dose responses. Essentially they do the
01:45:39.620
opposite effects, low and high concentrations. Now the color, the other, if someone's listening to
01:45:46.100
this, they'll remember the high school chemistry class. How do you demonstrate this to your students?
01:45:50.420
Yes. Well, when you add the powder of methylene blue into water, the water becomes very blue. And
01:45:57.700
then if you use a reducing agent, and I use vitamin C, ascorbic acid, because it's a
01:46:05.140
effective reducing aging, but it's harmless. When the methylene blue is reduced, it becomes transparent.
01:46:19.860
Clear. And this is, then you refer to it as leucomethylene blue. Leuco actually comes like
01:46:26.180
the same root, like leukocytes, the white blood cells.
01:46:29.460
So you call it the leucomethylene blue. That refers to the methylene blue being in the reduced
01:46:34.980
state as opposed to the oxidized state that is the blue. So methylene blue had major advantages,
01:46:42.180
but one of the cosmetic disadvantage is that once it goes through this process that I explained that
01:46:49.060
becoming trapped that was discovered by Ehrlich of becoming trapped in the nervous tissue. So it has
01:46:53.700
affinity for nervous tissue inside mitochondria. Eventually it goes back into the circulation. It
01:47:01.300
takes a half-life of about 12 hours with a dose that is a low dose that produces this
01:47:08.260
redox benefit. So it concentrates in the urine in the bladder. And actually here in the U.S. for
01:47:15.060
decades before the antibiotics were available, if you had a urinary bladder infection, you took
01:47:22.820
methylene blue pills. The methylene blue pills will start increasing the concentration of methylene blue
01:47:28.660
inside the bladder until it became a pro-oxidant while it was there. And it eliminated any bacteria
01:47:36.100
or virus in a non-specific manner. And it was a very effective, more effective way to eliminate
01:47:44.340
urinary bladder infection. For example, in older people that have chronic problems that they go through
01:47:50.100
round after round of antibiotics that debilitate them or create resistance, you could use methylene
01:47:57.860
blue. And is it because the methylene blue would, at a dose that was not toxic to the human,
01:48:03.700
once it concentrates in the bladder, it increases its concentration and therefore is toxic to the
01:48:08.260
organism? It will become oxidative and it will be toxic for the bacteria. Oh, so is it a Ross-induced
01:48:14.180
injury to the bacteria then? Correct. Ah, so you're basically going after the mitochondria of the
01:48:18.740
bacteria. Yes. Yes. It does the opposite, but it does it to the microorganisms that are inside the
01:48:24.900
bladder that are producing the infection. So it has the potential to do this in other situations,
01:48:30.900
but here naturally concentrates there. So that provides the advantage. But there are many things
01:48:37.060
about methylene blue I would not go into, but Ehrlich himself determined that the parasite that produces
01:48:44.500
malaria. The Plasmodium falciparum had an enzyme that was particularly vulnerable to not much large
01:48:54.500
concentrations of methylene blue were enough to affect this enzyme. So methylene blue became the first and
01:49:01.700
for a long time the only treatment for malaria. And this was a major breakthrough in medical research,
01:49:09.540
was in fact the first synthetic chemical used for a medicinal application in the history of medicine
01:49:17.540
and pharmacology, was methylene blue. And all of the first synthetic medicines were derivatives of
01:49:26.420
methylene blue, including in particular the late 1940s, early 1950s, the development of chlorpromazine,
01:49:34.420
chlorpromazine. The first psychopharmacological agent that was used for psychosis or what we call now
01:49:40.420
schizophrenia, in those days they would call it dementia precoce, because they were thinking that
01:49:47.140
it was the same kind of dementia that was happening in the older people, happening in the young people.
01:49:51.780
Now we make a separation between dementia and schizophrenia, but chlorpromazine is a methylene blue
01:49:57.700
derivative, and in fact there are reports as far as 1930s of physicians giving methylene blue mixes.
01:50:05.220
The problem was that in the original way that methylene blue was synthesized for textiles, there were a lot
01:50:11.860
of intermediary products as a result of the synthesis, and some of these were likely chlorpromazine.
01:50:19.780
So they were seeing anti-psychotic effects from giving these methylene blue preparations,
01:50:24.980
as I found reports in the 1930s and 1940s, and then it was picked up by a pharmaceutical company,
01:50:31.860
and by the end of the 1940s they developed chlorpromazine as the first anti-psychotic
01:50:37.540
medication, and that would change completely the face of psychiatry.
01:50:41.300
And it may have just been simply a chemical contaminant slash intermediary contaminant within
01:50:46.100
the formulation of methylene blue. So they thought the benefit was methylene blue,
01:50:55.940
Which is such a great story of chemistry in general, right? How easy it is to be fooled by
01:51:02.500
something that seemingly makes sense. Now today, the only FDA indication to my knowledge for
01:51:07.860
methylene blue is methemoglobinemia. Is that correct?
01:51:11.460
I mean, there's clinical trials that are going on to study this in Alzheimer's disease.
01:51:15.300
Yeah, let me clarify that because what happened is that methylene blue was being available for 120
01:51:22.100
years plus. So, methylene blue was grandfathered by the FDA. It preceded the creation of the FDA. So,
01:51:31.620
the FDA has not been able to resolve well how they deal with these grandfather drugs. Being the first
01:51:40.500
synthetic drug available. So, it was used for many things. I'm not going to go into all of them,
01:51:46.100
but malaria was probably the most important one until some Spanish and French explorers in South
01:51:53.460
America discovered from the bark of the tree, quinine. And then that happened and it became the next
01:52:00.420
generation after methylene blue. Nowadays, they're bringing back the methylene blue, especially in Africa
01:52:06.340
because there the plasmodium has become resistant to quinines. So, they are combining it. So, there's a
01:52:13.780
comeback for methylene blue in that respect. So, it is used medicinally for that. But the FDA never really
01:52:23.060
got to have a saying on it. So, what you're referring to is what has survived in what is called the U.S.
01:52:32.100
pharmacopoeia, these compendions of medications with indications. And in the U.S. pharmacopoeia,
01:52:39.460
that indication of methylene blue for methemoglobinemia has survived. Some of the others have been removed,
01:52:46.020
like I told you, for urinary bladder infections when the antibiotics became available. But it's being used
01:52:52.020
to protect the brain. You mentioned cancer early before we started the interview. Many of the drugs
01:52:59.300
that are used for chemotherapy have side effects that affect the brain, in particular mitochondrial
01:53:05.060
respiration. So, methylene blue, given before or during chemotherapy interventions, have been found to be
01:53:13.380
life-saving. One example is one called ifosfamide. So, ifosfamide-induced encephalopathy
01:53:21.620
happens in this chemotherapy. And there are many papers on this. However, the problem is the FDA will
01:53:30.900
not acknowledge these uses because there is no pharmaceutical company who is bringing these
01:53:37.140
materials. I guess this is sort of an impossible situation to understand because the FDA can't really
01:53:43.300
consider the approval for an agent or a use without an investigational new drug filing, an IND. There is
01:53:51.140
no IND, I assume, for methylene blue because there's no economics in methylene blue.
01:53:56.260
Yeah. There is no company that wants to invest because it's not patentable. They cannot protect
01:54:02.980
there with a patent. So, anybody can manufacture methylene blue and prescribe it or use it. In some
01:54:09.700
countries like Canada, it's freely available. Here in the US, it's unclear what its status is, but you can
01:54:18.020
get it through the internet. The problem is there are two problems. One, you have different purities. So,
01:54:26.020
you have at least three categories of purities for methylene blue. The one that should be used by in humans,
01:54:32.580
like in the emergency room, is the so-called pharmaceutical quality or the US, we call USP
01:54:41.460
grade. The Europeans have a similar, but the one in the USP is actually more restringent than the
01:54:48.340
European methylene blue. Then there is chemical quality that is used in laboratory for staining,
01:54:55.060
but that can go, for example, the one produced by Sigma has about 15% impurities. It should not
01:55:02.180
be given to live animals or humans and is readily available. So, I always want to warn against that.
01:55:10.020
And in many experiments with animals, they use that Sigma product. So, we don't know if we're confounding
01:55:15.780
the results of the experiments with the impurities. And impurities are very toxic. It has lead, it has
01:55:21.140
mercury, it has cadmium, it has a number of neurotoxic impurities. And then the other one is even less
01:55:27.700
pure is the industrial color of the genes to color the blue genes and other things. And that is even
01:55:33.380
more than 15% impurity and nobody knows for sure. Now, there was a company in Scotland several years
01:55:40.900
ago that ran a compound, LMTM. And the trial, which was announced, results of this trial were announced
01:55:49.140
about two years ago. And it was a big hoopla because the study, which I went back and skimmed the other day,
01:55:55.060
because I knew we would probably, I was hoping we would talk about this. The study basically
01:55:59.300
took patients in early stages of dementia, randomized them to various interventions,
01:56:03.460
but one of them was this agent, this LMTM, which they described as a methylene blue derivative. I don't
01:56:09.380
know how far a derivative it was. It might've been not much of a derivative.
01:56:13.860
It's essentially, you remember when I told you I added ascorbic acid and reduced methylene blue. So,
01:56:19.940
they've done something like this. They have reduced methylene blue, but they don't
01:56:24.340
use the name methylene blue. They use the name of methyltheonine chloride, which is a more chemical
01:56:31.300
name. And that's where the MT comes. And then the L is for the leuco.
01:56:36.260
Because it's clear. It comes in its reduced form.
01:56:48.180
Oh, yes. So it is clear that it's doing the redox cycles.
01:56:51.940
Now, what was very controversial about this was the primary endpoint of that study
01:56:58.660
was a neuroimaging outcome, and the primary output failed. There was no difference on neuroimaging.
01:57:09.620
There was a secondary outcome on cognitive function. And in a subgroup analysis, which again,
01:57:16.420
the statisticians will say, they cry foul, right? And understandable. You can't start parsing the data.
01:57:22.420
Yes. But the argument was the subset in which this benefit was seen, which was about 15%. And if I
01:57:29.700
recall, it was only patients that received the LMTM in monotherapy. So what we don't know,
01:57:34.820
unfortunately, because this to me left a lot of questions unanswered, right?
01:57:38.980
It certainly suggested there's something going on with methylene blue.
01:57:43.060
But are we being misled because the combination of methylene blue
01:57:55.460
Oh, yes. However, let me clarify. These individuals have never presented methylene blue
01:58:01.460
or understood methylene blue from the point of view that are being presented to you as a metabolic
01:58:07.060
enhancer, or it could be a metabolic poison too, but in low concentrations.
01:58:13.380
The low concentrations as a metabolic enhancer acting on the mitochondrial respiration.
01:58:19.060
They have been presenting these as an anti-tau medication.
01:58:23.860
That's correct. The entire company, which whose name I forget now.
01:58:31.060
Yeah. Yeah. That's the other thing that interested me, which was...
01:58:36.100
They might have backed into something interesting potentially.
01:58:38.660
Yes. And I say this here publicly. It is unfortunate that they have done this this way
01:58:46.180
because they are undermining the potential benefits of methylene blue. The biochemist who is behind
01:58:54.500
the hypothesis I'm not going to name, he found that in vitro at relatively large concentrations to
01:59:03.940
based on what I'm telling you about mitochondrial respiration, it prevented the phosphorylation
01:59:10.580
and agglutination of Tau in vitro. So they then infer, oh, this is an anti-Tau agent.
01:59:20.100
If you test methylene blue with immediate different compounds, depending on the concentration of
01:59:26.900
methylene blue, because it has reducing or an oxidating action, it will interfere with all kinds
01:59:33.300
of phenomena. There's nothing specific about methylene blue.
01:59:36.180
This may be true, true, and unrelated. Its effect on Tau, whether correct or incorrect,
01:59:43.620
And not only that, the effect is dose dependent. In other words, in vitro,
01:59:49.380
the more concentration of methylene blue had, the more you interfere with the Tau aggregation.
01:59:54.660
In other words, you don't see this bimodal dose response.
01:59:57.460
No, because they were actually working on the high end of concentration.
02:00:02.260
So does that mean they weren't even looking to see what the toxicity was in the mitochondria when
02:00:08.100
They did some later work to address this when they wanted to move this to the FDA. But the point is,
02:00:16.580
in the first studies from this group, the most effective dose was the lowest dose.
02:00:32.980
In the first study, they found some effect with the very low dose. And in the higher doses that
02:00:40.740
would approximate these anti-Tau effects, they found no effects. And they turned this around
02:00:47.540
in such a way that in one of the papers published in the Journal of Alzheimer's Disease, that a friend
02:00:54.420
of mine is the editor, they claimed that actually the highest dose, there was a problem with
02:01:01.460
absorption. And it was really a low dose. And the lowest dose was more easily absorbed. And it was
02:01:11.860
really then the high dose. And then they changed the results to indicate, oh, the low dose was the
02:01:19.700
high and the high dose was the low. And that's why it worked. So in other words, they did not change
02:01:24.740
their hypothesis that was contradicted by their data, which is the same thing that's been happening with
02:01:30.820
the amyloid people. Their results do not support the hypothesis and they keep blindly moving forward.
02:01:37.140
So now what you explained was because they have difficulties getting a patent for this compound,
02:01:45.540
they created this reduced version of methylene blue and did similar studies. But in that study,
02:01:54.020
they had the problem that the majority of the people, if you are having Alzheimer's disease and you're
02:02:01.460
in a hospital or being treated by usually neurologists or sometimes psychiatrists, they would prescribe,
02:02:08.740
unfortunately, unfortunately, drugs that have no benefit to the patients, but produce adverse effects
02:02:17.140
such as cholinesterase inhibitors and memantine. And the idea being is, well, this is the standard
02:02:23.780
of care. It would be, quote unquote, unethical to take these patients off these agents, even to allow
02:02:29.140
them to enter another trial. Well, that may be the reasoning that some people may have, but that's
02:02:34.500
actually the opposite of what's happening. These drugs are ineffective and it's unethical to continue
02:02:40.900
to use these ineffective dose that are having these toxic and adverse effects on people. If you go back
02:02:48.100
to the original studies that were used by the FDA to approve these drugs and the reviews that were done
02:02:54.900
subsequently by like the cross-chain groups meta-analysis, they all conclude very clearly that these drugs
02:03:02.260
are ineffective and they do not improve activities of daily living and that the disease continues and
02:03:10.340
progress and people die. In fact, in countries where they have more elaborate longitudinal data like in
02:03:17.460
the UK of administration of these compounds to patients with Alzheimer's, they know
02:03:24.900
that they die sooner if they're taking these medications that the ones that refuse to take them.
02:03:31.380
And the UK made an attempt. In fact, they banned these compounds because they had evidence-based
02:03:37.860
that not only they were ineffective, but they were counterproductive. And within a year,
02:03:43.380
the public demanded to the politicians because if they're used in the US, they must be beneficial.
02:03:52.020
And so this is a decision that was done politically motivated to bring them back and make them
02:03:58.900
available, even though we have all the evidence, just like we have against the amyloid hypothesis,
02:04:05.620
that the cholinergic hypothesis of Alzheimer's disease is also irrelevant.
02:04:10.820
Actually, it's funny. I didn't realize people still subscribe to that hypothesis.
02:04:14.660
The most commonly prescribed medications are the cholinesterase inhibitors. And then the FDA did
02:04:21.540
not approve memantine for early Alzheimer's or mild Alzheimer's or mild cognitive impairment. They
02:04:29.140
approved originally only for severe and then later for moderate and severe, which was very unfortunate.
02:04:36.740
The memantine is preventing some of the excitotoxicity that is damaging those hippocampal cells.
02:04:43.300
But essentially what you're doing when you do that, you are rescuing from dying a cell that is
02:04:52.180
Yeah. So indirectly, which is interesting because there was a study that came out about a month
02:04:56.420
and a half ago on memantine. And I remember, you know, this is obviously not my field of expertise.
02:05:00.260
So my level of knowledge in the literature is so much less than other areas. But the problem with
02:05:05.940
that could be that you're actually rescuing a cell that's going to go on to send a signal that could
02:05:13.860
It is completely counterproductive. And it's based on the pathology, pathology oriented,
02:05:19.540
that you can see more of these neurons there when the people die.
02:05:22.980
But it's not a functional assay. In other words, it's a neuropathological, which there's,
02:05:28.100
there's value in these things, but it sounds like the real overarching challenge here is
02:05:32.500
triangulating between neurobiology, anatomy, functional signaling. And then of course,
02:05:37.700
ultimately clinical outcomes matter more than any of these other things in the end.
02:05:41.700
I agree. And that's what should direct all of this in the first place. And it's not what's happening.
02:05:47.700
Now, I know this is a little outside of the work you do, but do you have a point of view on the
02:05:52.260
recent excitement around herpes simplex virus one? Have you followed that discussion?
02:05:57.620
No, no. I don't have a good point of view. What I can tell you is we found another way
02:06:03.460
to try to intervene with mitochondrial respiration using light, in particular infrared light that can
02:06:11.140
go through the tissues. And the photons in the near infrared light are absorbed by cytochrome oxidase.
02:06:20.180
It turns out that cytochrome oxidase, that's the name cytocell, but chrome color,
02:06:26.260
is because of it absorbs certain wavelengths and it reflects others. So it's the chemical in the cell
02:06:32.420
that gives color to the cell. And this property of photonic absorption we have used in conjunction
02:06:40.500
with the laser delivery of near infrared light transcranially through the forehead as a source of photons
02:06:48.580
that actually oxidizes, photo oxidizes cytochrome oxidase. And by doing that, the enzyme has more
02:06:56.820
affinity. That's the conformation of the enzyme that has more affinity to oxygen, peroxygen consumption.
02:07:04.020
Yeah, I just pulled out a picture that we'll make sure we link to in the show notes that comes from
02:07:08.740
one of your papers, actually, where it shows in the same figure a close section of the mitochondria.
02:07:14.020
And you can see the effect of methylene blue and also the effect of near infrared light. Now,
02:07:20.260
it strikes me as interesting that you can get the wavelength just right because you have to
02:07:24.180
be able to get through not just the tissue, but the skull itself.
02:07:27.140
Actually, the skull is less of a problem. It's easier to go through.
02:07:30.580
Because it's porous because of the bony matrix?
02:07:32.500
Yeah, because there is less circulation through it. One of the big bromophores that we have is hemoglobin.
02:07:39.540
I see. So hemoglobin can absorb and reflect much of this light before it actually reaches the neurons.
02:07:44.340
So what we try to do is we move away from this peak of exhaustion, so oxy and deoxy hemoglobin,
02:07:51.620
to one that is still can be absorbed by cytochrome oxidase.
02:07:57.620
We use 1,064 nanometers wavelength, so around 1,000, which is a wavelength that is not very well studied
02:08:06.500
in biochemistry. Most of the spectrophotometers in biochemistry, they do not go all the way to 1,000.
02:08:18.020
Yes. But the longer the wavelength, the more it penetrates to the tissues.
02:08:24.500
How do we know how safe that is? I'm sure somebody listening to this is going to say,
02:08:32.500
Of course, it's a different wavelength. No, I understand. But as the sort of lay person,
02:08:37.620
Yeah, microwaves moving the other direction. But the longer the wavelength, the less energy they
02:08:42.580
carry. So the less they can penetrate. So they cannot really penetrate inside atoms,
02:08:48.260
like the ones that have short wavelengths. But they are good enough to penetrate to the tissues,
02:08:54.740
not very deep. And only about one to two percent, if we do it transcranially through the head,
02:09:01.220
actually goes through to the surface of the cerebral cortex. Once in the cerebral cortex,
02:09:07.380
the white matter is also a barrier. So the effect of the photons is primarily in the gray matter layer of the cerebral cortex.
02:09:17.780
And what it does is you're donating these photons to the electron transport. So you're bypassing
02:09:25.380
the electron donors. The photons are not identical to electrons, but they act in a similar way in the
02:09:33.700
electron transport. So the photons and the electrons are very similar. The difference is that the
02:09:39.460
electron can carry a very small mass. The photons essentially do not have mass. And by providing
02:09:46.260
photons to the electron transport, you keep the electron transport going, because these enzymes
02:09:51.460
engage in the redox changes. And the more photons you send to cytochromoxidase, the more of the
02:09:59.460
enzymes quickly goes to the oxidized conformation. And that oxidized conformation is the one that has
02:10:05.780
more affinity to bind oxygen. But I don't understand, how is this actually making its way systemically to
02:10:11.780
the brain through a transcranial stimulation? When you aim through, for example, the forehead,
02:10:18.900
it goes through the tissue and reaches the surface of the cerebral cortex. And that's how it makes its
02:10:26.980
way. It's more localized. It's different from, it's not a systemic administration like methylene blue.
02:10:32.980
And is it enough to just be able to hit the frontal cortex to create a clinical improvement without
02:10:40.100
impacting the mitochondrial function deeper in the midbrain or lower part of the cortex?
02:10:46.340
To create a functional improvement. We don't know yet about clinical. Especially,
02:10:52.020
I would not say that in somebody with the degree of atrophy that many of the Alzheimer's patients
02:11:00.100
have, we're going to have enough substrate there to be able to stimulate and reverse the disease. So
02:11:08.660
this will have to be tested with clinical population. Are there clinical trials that are
02:11:13.460
going to be looking at this near-infrared light strategy combined with methylene blue?
02:11:18.660
No, not combined. You don't think of these as synergistic. You'd consider these separate
02:11:23.140
approaches? Yeah. I consider them separate approaches. The reason for this is the following.
02:11:29.300
Methylene blue can affect these photons. Ah, of course. That makes sense. Yeah.
02:11:34.900
And this is actually used nowadays. For example, dermatologists, if you have a melanoma,
02:11:43.300
a cancer in your skin or any other lesion, they can inject methylene blue into that region. And then
02:11:50.660
they just shine light and the light- Concentrates the light.
02:11:55.380
Into methylene blue and the methylene blue oxidizes. It has-
02:11:59.780
You had that Ross reaction, the same thing that you see in the bladder.
02:12:02.580
Correct. And it kills those cells there. And this is called photodynamic therapy.
02:12:07.380
It has many applications because if you have a virus that you have no other way to kill,
02:12:13.940
you can always kill it this way. So this is happening. Even people don't know methylene blue
02:12:20.340
is injected into blood that is used for transfusion so that you can then treat this blood with these
02:12:26.740
bright lights. And by photodynamic therapy, kill viruses like the HIV virus or the herpes.
02:12:34.180
Is there a difference between giving the methylene blue orally versus intravenously for this purpose
02:12:39.940
specifically? Yes. The intravenous one, the first target will be the blood cells. So you have to be
02:12:46.820
more careful with the concentration because you don't want to promote the methemoglobinia. In other
02:12:52.660
words, to compete with oxygen. Yeah. So it seems safer to administer orally. Yes. The oral administration
02:12:57.700
produces slower release and in low concentration is very safe. And it's, like I say, it's being done
02:13:06.740
in thousands and thousands of people for malaria. And these studies that have been published in the
02:13:12.980
last few years have primarily given to children in Africa for killing the parasites. And in that case,
02:13:20.500
the oral administration had the advantage that many of these parasites are- In the gut as well.
02:13:24.980
Yeah. In the gut so you can have the higher amounts there.
02:13:28.740
So going back to this broader perspective, I mean, the clear theme here is, which I think is
02:13:34.420
that prevention matters. In fact, we shouldn't be focusing so many resources on the treatment of
02:13:40.260
clinically evident apparent dementia for the reasons you've discussed. So now what we want to do is
02:13:46.020
prevent. I was going to say prevent in high risk individuals, but as one of my friends who's a
02:13:50.340
neurologist would say, anybody with a brain is at risk. So let's stop stratifying as who's high
02:13:55.380
risk versus low risk. Everybody should take a preventative measure. Yes, definitely. In addition
02:13:59.940
to this idea of all the things that matter in the heart. So lower smoking, lower blood pressure,
02:14:05.940
better glycemic control, better management of lipoproteins, et cetera, et cetera. Is there anything
02:14:10.260
that you see as unique in the brain specifically that is maybe not unique or maybe not as important
02:14:16.580
in the prevention of cardiovascular disease? The only one that I would say will have to do
02:14:22.740
with the ketogenic diet. Ketogenic diet will facilitate mitochondrial respiration in a different
02:14:29.620
way, but this will contribute to targeting mitochondrial respiration. So that the brain will benefit
02:14:39.540
more than the heart. The heart will benefit, of course. All of these tissues will benefit, but
02:14:45.220
because of the brain reliance on aerobic metabolism. For example, you alluded, for example,
02:14:51.380
on insulin resistance. One of the problems that happens as the brain ages, even in normal people,
02:14:58.740
is that the transport of glucose is affected. So even though we can increase glucose levels in the blood
02:15:06.100
or what we're eating, we cannot get that glucose being transported to the brain as effectively as in the
02:15:13.140
younger individuals. That's why some of these studies with intranasal insulin administration
02:15:18.340
show transient improvement in symptoms, presumably because they're becoming resistant to glucose. Now,
02:15:24.980
that's obviously not a long-term solution. No. But it illustrates a point. And fortunately,
02:15:31.140
insulin primarily facilitates glucose transports in other tissues other than the brain. The brain
02:15:37.860
actually doesn't require insulin. It can boost its transport of glucose, but the reason for that is
02:15:44.180
that when you wake up in the morning that you have been fasting overnight, whatever levels of glucose
02:15:51.780
are circulating in your blood, then the brain tissue will be the only one that will be able to take
02:15:57.380
that up. And it's only when you have large glucose levels that then insulin is released by the
02:16:03.700
pancreas and then all the tissues then can use it, can feast on it. So the ketogenic diet, so ketone
02:16:11.940
bodies can act as an alternative source for energy in the brain. And the important point is
02:16:19.540
that even though glucose is a preferred substrate during aging, this is compromised, this uptake.
02:16:29.060
However, the uptake of ketone bodies is not compromised. Therefore, you could satisfy some of these
02:16:36.660
nutritional requirements by adding the ketone bodies to the diet. Do you think it matters if a
02:16:44.340
person is on a ketogenic diet or if they're on a non-ketogenic diet, but they supplement with exogenous
02:16:49.860
ketones? I hope it doesn't matter. As long as you have the ketone bodies available, you don't require to have the
02:16:59.220
ketogenic diet itself. But this eventually will have to be resolved empirically. And there is no question that
02:17:07.220
this is going to promote mitochondrial respiration. And we know, as you know, when we're born as infants,
02:17:13.220
we rely primarily for neural function and everything else on these ketone bodies produced by the liver,
02:17:20.980
but because of the kind of lipids that we get through the mother's milk. So essentially,
02:17:27.860
what we're trying to do is bring in somebody who is in all age to rely more on ketosis. That is a process
02:17:36.740
that we know exists under physiological conditions every day. If we go beyond, you know, 12, 14 hours
02:17:43.380
without eating, we start generating this. But it's something that we know in infancy is the primary
02:17:50.260
source for the brain. I didn't realize that. Is that more a result of their livers not being able to
02:17:55.780
release enough glycogen via glucose and hepatic glucose output? I mean, I know they have a very
02:18:01.060
high demand for energy. Yes. Can you measure the ketone in their blood? Yes. But it is because of
02:18:06.980
the source of food that they're taking. I see. So they're basically getting
02:18:10.420
medium chain triglycerides through the milk. Exactly. Yes. The medium chain triglycerides
02:18:14.820
being the main source there for energy conversion as opposed to some of the other triglycerides.
02:18:20.500
So the original bulletproof coffee is actually mother's breast milk before it is...
02:18:25.140
That's right. The fancy coffees that everybody drinks. Yes. So I do believe that that's another
02:18:31.220
alternative. So in essence, you could potentially have pharmacological interventions that address
02:18:38.180
mitochondrial respiration, but they will not have to be classic pharmacology like neurotransmitter-based
02:18:44.020
pharmacology. There will be more of a metabolic pharmacology. You can have near-infrared light by
02:18:50.260
providing this photonic stimulation. However, that one is targeted. It's not systemic like you pointed
02:18:56.980
out. So one will have to find the target. Luckily, the forehead is more accessible. We don't have hairs.
02:19:03.620
And we can target that prefrontal cortex that shows the initial cognitive difficulties as people become
02:19:11.380
older. And that's what we have been doing. And then the third one will be through the diet, which you
02:19:17.060
facilitate. Because as you pointed out, the insulin resistance is because our glucose levels are going
02:19:23.140
up because we cannot transport it into the tissue, especially nervous tissue, which was a primary
02:19:29.140
consumer has effectively. And then we have these high levels of glucose for longer times. So there's more
02:19:35.780
insulin that is being released. And then this desensitizes the receptors. So there is a natural
02:19:43.380
development of metabolic syndrome as we grow all because of this phenomenon. This manifests itself
02:19:51.060
then has less substrate for energy for the brain. And then you have a cognitive decline
02:19:56.980
accelerated associated with obesity and hypertension and this insulin resistance. So it's all part of the
02:20:05.620
same age-related picture. And probably people eat more because they are trying to make up for this lack
02:20:12.660
of energy that the brain is consuming. And if any organ is more liable to influence our eating behavior,
02:20:21.380
it will be the neural tissue. That's such an interesting thought because I've always believed,
02:20:26.340
as you've suggested, that I think our appetite is driven by fundamentally important physiologic
02:20:32.020
processes. And starvation would be the most important among them. And starvation in the modern world
02:20:37.860
doesn't look like starvation in the prehistoric world. Starvation in the modern world can be
02:20:42.420
in the presence of obesity because we're not talking about the obvious, we're talking about
02:20:47.620
the cellular level. And so if cellular metabolism is deficient, which is often the case in insulin
02:20:53.060
resistance, an individual can be functionally starving and that can drive it. Now, I've always
02:20:58.180
thought about it through the lens of the liver, but you're making an argument that says there's also a
02:21:02.020
central starvation that could be also driving these repetitive changes. Yes. But there are also
02:21:08.180
peripheral components, like you say. For example, in the case of the obese, an individual that has
02:21:14.740
obesity will, by almost definition, will have down-regulated the ketogenesis. The ketogenesis
02:21:25.300
enzymes will not be upregulated unless you're consuming your own fat. And these are trainable
02:21:34.020
enzymes, like inducible as well. So if you don't go through periods of fasting, you cannot elevate
02:21:42.900
these enzymes. So somebody who is obese and suddenly stops eating is starved because his body cannot,
02:21:52.180
it doesn't have the metabolic presence of hyperinsulinemia. It is a very painful transition
02:21:58.100
into fasting. You cannot use your body fat to, to feed, especially the brain, which is the first
02:22:04.020
one that is going to give you these signs and symptoms. So the first thing that somebody has to
02:22:09.060
do is start out by having a periodic periods of fasting that in, in my own case, I do it once a week,
02:22:16.660
usually between Friday and Saturday. I fast for at least 14 or 16 hours. You know, it's not difficult
02:22:23.700
to do. If you have an early meal and then a late brunch, you will have significant fasting and you
02:22:29.780
can accelerate that process by consuming some of the circulating glucose if you do a workout that
02:22:36.580
morning. So by doing that, I am allowing my body to build up these ketogenic enzymes. And therefore,
02:22:45.620
then during a regular day in the week, if I don't eat anything between meals, I don't feel hungry
02:22:52.660
because I can consume my own body fat. And people who are obese cannot do that. They don't have the
02:23:01.220
biochemical machinery to do it. So I believe that's probably the third way of approaching this problem.
02:23:07.860
If those three things could be used, and like I say, it may not be possible to combine some of them,
02:23:13.700
like I will have to empirically determine how much methylene blue one can have systemically
02:23:18.900
so that to not produce a photodynamic effect. When I do transcranial laser stimulation,
02:23:26.420
we hope in the future we may be able to do this with LEDs. Right now with the LEDs are
02:23:32.740
commercially available. We haven't been able to find the results that we get, but we, we are investing
02:23:39.460
time in trying to, to change this so it will be safer and cheaper to do. So right now the only ones,
02:23:48.420
so my bioengineering colleagues has been able to collaborate with me and develop a device that we
02:23:56.260
can transcranially do imaging with near infrared spectroscopy and actually measure the concentrations of
02:24:04.820
those oxidized cytochrome oxidase in vivo in the human brain. And we published that last year.
02:24:10.980
And this allows us to directly have a measurement that we are indeed engaging our target. And this
02:24:18.980
also will allow us to find what is the optimal dose response for that particular brain. Because like you
02:24:25.940
indicated, different people have different heads and the transmission would not be equivalent.
02:24:31.060
So this is what we're doing. And so we have obtained three major grants for doing this with the
02:24:37.780
bioengineering group in the Dallas area. For example, Professor Hanley Liu, we are doing the
02:24:44.580
development of these devices to monitor the physiological changes. And this is a grant by NIH that is called the
02:24:52.980
Brain Initiative Program. And then here with my colleague Andreana Halley, we are, have a grant from the
02:25:01.140
National Institute of Aging to test this transcranial near infrared light in older people and people with mild
02:25:09.780
cognitive impairment. And then the third has been a benefactor who's giving us large amounts of money so that we can
02:25:19.780
pursue this line of work with the transcranial lasers. And I can show you the endorsement from
02:25:27.140
some of the people in the field. Oh yeah, I'll take a picture of this and we'll put this on. In fact,
02:25:32.180
it was actually Jack who directed me to speak with you maybe six months ago. This is exciting. You know,
02:25:37.860
I want to add one other thought to this, which is I hope that if somebody's listening to this who's involved
02:25:42.500
in traumatic brain injury, that someone ought to look into a clinical trial of using methylene blue
02:25:48.740
as a rescue agent during periods of traumatic injury, because again, mechanistically, it's at least
02:25:54.260
plausible that you could salvage and rescue some of the transient insult and the damage that goes through
02:26:02.340
that. And again, there's another example of a disease for which we don't seem to have any solution
02:26:07.860
other than the obvious, which is avoidance of the injury, the insult. But there's still
02:26:12.660
a lot of people out there that are being exposed to repetitive head trauma. And as you probably know,
02:26:18.980
there's been some interesting hypotheses around the presence of ketones in the system before
02:26:25.220
traumatic injury and potentially a salvage after. But it seems to me that this methylene blue story
02:26:30.260
probably deserves a bit more attention in other areas, given these properties you've described.
02:26:34.900
I actually agree with you. And I would say, because it's using emergency rooms, I believe in every
02:26:41.540
ambulance, you should have methylene blue available. And if there is any insult that compromises
02:26:49.220
metabolic supply to the brain, you're going to be better off infusing methylene blue at a low
02:26:55.620
concentration. We're talking about one milligram per kilogram concentration that is going to be
02:27:02.180
be neuroprotective, regardless of the source. It could be transient ischemic attract. It could be
02:27:08.980
in a stroke. We have done this in a stroke models in animals using the methylene blue. And we've been
02:27:14.580
able to rescue the majority of the damage produced in the infarct in animal models. And animal models,
02:27:22.100
when we look at this longitudinally using fMRI. So we know this works in animals. I've just been unable to
02:27:29.780
convince emergency physicians to start doing this to their ischemic patients. And not only for the brain,
02:27:36.740
but ischemia affecting all the other organs is being also tried in animal models of neurotrauma with
02:27:44.500
the similar benefits. So the problem is there is no interest by the pharmaceutical company because they
02:27:51.780
cannot make money on it. And unfortunately, the NIH is also influenced by, if you're using an old drug,
02:28:00.820
essentially you're repositioning this old drug for these other applications as a neuroprotective
02:28:06.100
agent or more generally metabolic protective agent. They are concerned that their investment is not going to
02:28:14.660
pan out because when it goes to commercialization, you're not going to be able to patent that medication.
02:28:21.220
And believe it or not, even though if it works, if there is no prospect that profits can be made,
02:28:28.020
they don't want to invest. Yeah, it's a shame because I worry that we'll be in this state of
02:28:32.180
limbo where we're not really going to know the answer and we can't know the answer without clinical trials.
02:28:37.700
This is about as easy an agent as there is to study given its long history, its relatively well
02:28:43.300
understood toxicity profile, and in many cases, the speed with which you could see a response,
02:28:48.580
especially if you're studying ischemic events. And I will tell you that just a couple of years ago,
02:28:55.380
it was published last year, the group that I collaborated with in San Antonio, we were the
02:29:00.580
first to show the effects of methylene blue in the human brain using fMRI and measuring blood flow and
02:29:09.140
measuring ball signals. And also in those subjects, we did memory testing and we were able to demonstrate
02:29:16.740
a significant improvement in their memory retrieval just after an acute treatment with methylene blue in
02:29:24.020
a blind placebo control study. The first time that that was done, contrary to these other groups that are
02:29:31.860
doing it as an anti-tao aging in healthy and older people, we can improve memory and we can demonstrate
02:29:41.380
using imaging that we can do this through methylene blue. So the only problem is that there's not going
02:29:47.940
to be any profit because I believe if some company would like to develop this purity pharmaceutical grade
02:29:54.660
methylene blue, there will be a huge market. Other companies may imitate them, but there's enough for
02:30:01.300
everybody. Still, the cosmetic aspect of having urine that is this color is a problem. Many people
02:30:09.940
Yeah. Well, Francisco, this has been great. You've been very generous with your time and I really
02:30:17.380
appreciate this discussion. I've learned a lot and I'm guessing that people listening to this will
02:30:21.380
have also learned a lot. So we will have a great set of show notes to accompany this where all of
02:30:27.300
the papers that we've talked about, a link to Jack's book and a number of other things will be
02:30:32.020
included so that hopefully it's a reference for anyone else you want to share this with and
02:30:36.500
certainly anyone listening. So thank you very much.
02:30:41.700
You can find all of this information and more at peterattiamd.com forward slash podcast.
02:30:46.900
There you'll find the show notes, readings, and links related to this episode.
02:30:51.060
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02:31:20.900
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