Venki Ramakrishnan

But of the ones that actually made it into adult animals, a number of them had normal lifespan and apparently normal health. So at least in those cases, and of course there was ruthless selection involved because as I said, most of these embryos failed to take. But nevertheless, it is possible, at least in theory, to reset the aging clock, just as we naturally do every generation.

But of the ones that actually made it into adult animals, a number of them had normal lifespan and apparently normal health. So at least in those cases, and of course there was ruthless selection involved because as I said, most of these embryos failed to take. But nevertheless, it is possible, at least in theory, to reset the aging clock, just as we naturally do every generation.

And that involved wiping out the signals, the programs of which genes are expressed, back to an early embryonic state. And that program is different from, the skin cell makes only a subset of genes, that we have. And it's a different subset from a brain cell or a heart cell or a blood cell. But you could take it all the way back.

And that involved wiping out the signals, the programs of which genes are expressed, back to an early embryonic state. And that program is different from, the skin cell makes only a subset of genes, that we have. And it's a different subset from a brain cell or a heart cell or a blood cell. But you could take it all the way back.

that you need tissue regeneration. And it turns out that, and you need to recycle bad products. You need a number of things that have to happen that become dysfunctional as we get older. And it turns out one of the things that allow us to be healthier in old age is caloric restriction. Again, there's a big debate about that because they're always comparing

that you need tissue regeneration. And it turns out that, and you need to recycle bad products. You need a number of things that have to happen that become dysfunctional as we get older. And it turns out one of the things that allow us to be healthier in old age is caloric restriction. Again, there's a big debate about that because they're always comparing

animal that gets just the bare number of calories it needs to live without starving. The animal is not losing weight and becoming lethargic. It's getting the bare minimum, though, to live. And they're comparing that with Animals that can eat all they want, an ad libitum diet. And there's always a difference.

animal that gets just the bare number of calories it needs to live without starving. The animal is not losing weight and becoming lethargic. It's getting the bare minimum, though, to live. And they're comparing that with Animals that can eat all they want, an ad libitum diet. And there's always a difference.

Now, some people have argued, including Leonard Hayflick, who was the first person to discover that cells can only divide a certain number of times, which eventually was explained by telomere loss and so on. But that guy died, by the way, Leonard Hayflick died in his 90s, only about a month or two ago. Anyway, he was a skeptic.

Now, some people have argued, including Leonard Hayflick, who was the first person to discover that cells can only divide a certain number of times, which eventually was explained by telomere loss and so on. But that guy died, by the way, Leonard Hayflick died in his 90s, only about a month or two ago. Anyway, he was a skeptic.

He said, all this shows is that an all-you-can-eat diet is bad for you. Because in the wild, you never have all you can eat. This is a problem of a plentiful food supply, civilized society. But nevertheless, caloric restriction makes a difference, and it does affect a number of pathways. And people have found out that there are drugs that can inhibit some of these pathways.

He said, all this shows is that an all-you-can-eat diet is bad for you. Because in the wild, you never have all you can eat. This is a problem of a plentiful food supply, civilized society. But nevertheless, caloric restriction makes a difference, and it does affect a number of pathways. And people have found out that there are drugs that can inhibit some of these pathways.

And those drugs will often have some of the benefits of caloric restriction, maybe many of the benefits of caloric restriction. One of them called rapamycin was discovered in this very odd way. It has a fascinating history, how it was discovered. But it inhibits a major pathway called the TOR pathway. but which is also restricted by caloric restriction, inhibited by caloric restriction.

And those drugs will often have some of the benefits of caloric restriction, maybe many of the benefits of caloric restriction. One of them called rapamycin was discovered in this very odd way. It has a fascinating history, how it was discovered. But it inhibits a major pathway called the TOR pathway. but which is also restricted by caloric restriction, inhibited by caloric restriction.

And so when they tried to give rapamycin to older animals, those older animals did seem to have improved health and improved symptoms and also lived a bit longer. So it's become a darling of the aging, some of the aging research community. But rapamycin is also the reason that it was known as a drug was because it's immunosuppressant.

And so when they tried to give rapamycin to older animals, those older animals did seem to have improved health and improved symptoms and also lived a bit longer. So it's become a darling of the aging, some of the aging research community. But rapamycin is also the reason that it was known as a drug was because it's immunosuppressant.

It's given to transplant recipients to prevent organ rejections. And you wouldn't want to take an immunosuppressant all your life. I mean, if you're an organ recipient, you would, because otherwise you'd die, you'd reject your organ. But the equation's different if you're normally healthy. Why would you want to risk infection? And then it has all sorts of other side effects.

It's given to transplant recipients to prevent organ rejections. And you wouldn't want to take an immunosuppressant all your life. I mean, if you're an organ recipient, you would, because otherwise you'd die, you'd reject your organ. But the equation's different if you're normally healthy. Why would you want to risk infection? And then it has all sorts of other side effects.

So the aging, some of the rapamycin advocates would argue that, well, maybe there's a dose at which it has the benefits without the side effects. Or maybe we can find compounds similar to rapamycin that don't have the side effects but have the benefits. So that's an ongoing research field. And I would say that's a valid field.

So the aging, some of the rapamycin advocates would argue that, well, maybe there's a dose at which it has the benefits without the side effects. Or maybe we can find compounds similar to rapamycin that don't have the side effects but have the benefits. So that's an ongoing research field. And I would say that's a valid field.