Brian Kennedy, one of the leading experts in the study of human aging, spoke about whether there is a limit to human life, and explained why the fight against aging is today the main task for all countries in the world.
For nearly three decades, Professor Kennedy has been studying the various processes that cause the human body and cells to age, and is trying to understand how this process can be stopped by experimenting with animals and volunteers.
Two years ago, his team discovered two hundred genes, possibly associated with aging, by conducting experiments in yeast with partially human DNA. These experiments served as the basis for the first experimental anti-aging therapies, which will soon begin clinical trials in volunteers at the Kennedy Laboratory at the National University of Singapore.
Last week, he gave a public lecture at the PhystechBioMed conference organized by MIPT, during which he talked about what his laboratory has achieved, how alcohol affects the rate of decrepitude of the body and why the governments of Singapore and the United States are putting the fight against the aging of the world's population, "Gray tsunami", to one of the first places among their national interests.
Brian, in recent years, your colleagues often argue about whether there is a limit in a person's life that cannot be crossed. Does he exist or not?
- This debate has revived in recent years for the reason that colleagues recently conducted several studies on the life expectancy of the oldest people on Earth. They showed that the average life expectancy on the planet has continued to grow in recent years, but its maximum values have not changed.
I look at this problem from a slightly different angle, since I work mainly not with people, but with animals. Whatever organism we work with, in all cases we have managed to increase the maximum life span. There is no reason to believe that this cannot be done for a person.
On the other hand, this question, in fact, is somewhat different: we do not yet know for what reasons the maximum life expectancy grew earlier, were these some natural factors or some actions of the person himself. In the future, when we start using life-prolonging drugs, I am sure they will work on the longest-living people too.
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Many of your colleagues in Russia believe that there is a genetic “aging program” that makes animals grow decrepit and give way to a new generation. Do you agree with them?
- Two different issues are raised here. On the one hand, the data that we have to date indicate that such a program does not exist and that the decrepitude of the body occurs by itself.
The reason for this is natural selection - its influence on how the body of humans and animals weakens after they have already left offspring and stopped reproducing. From the point of view of evolution, human life ends at the age of 30-40, and this was true throughout most of human history, since almost all of our ancestors extremely rarely lived up to this mark.
For this reason, those errors in DNA that affect our life after the end of this period were practically not corrected in the course of our evolution, which began to interfere with humanity only in the last 200 years, after the advent of medicine and the start of a sharp increase in life expectancy. Chronic diseases have emerged, killing more and more people.
On the other hand, even if this program does not exist, it cannot be said that the impact on single genes or groups of genes cannot affect the rate of aging. Despite the fact that aging of the body is largely a random process, some of its features are common to humans and many other animals, and this can be used.
For example, calorie restriction lengthens the life of many animals, not because it directly slows down aging, but because lack of energy “turns on” the sets of genes associated with stress and lack of food. These genes appeared in our DNA and in the genomes of animals, not because they are associated with aging, but because they helped them survive in difficult situations. This same protection against stress has been shown to help the body better resist aging.
Speaking of animals, today scientists are trying to find the key to aging, experimenting on a variety of creatures, from yeast to naked mole rats. Which one will get us closer to solving this riddle?
- In fact, there is no answer to this question, since each animal makes its own contribution to the study of aging. For example, yeast and fruit flies are completely different from humans, but their short life cycle allows us to quickly study the work of individual genes in their DNA. As it turned out, many of these genes associated with aging have their analogues in the DNA of mice and, possibly, humans.
On the other hand, truly long-lived creatures, such as naked mole rats, help us study other processes that are extremely difficult to catch or notice in experiments with yeast or flies. In general, we must conduct research on all model organisms, taking advantage of the differences in their life.
Have you succeeded in making new advances in the study of aging genes using your yeast with human genes as an example?
“We have been researching yeast for a very long time, and now we can say that these fungi have played a key role in the study of aging, as they helped us find the SIRT2 and mTOR genes, the effects on which helped us significantly prolong the life of mice and other animals.
Now we are trying to get a complete picture of aging - how this process is influenced by not one, but all 230 genes that we discovered two years ago, and how they interact with each other. This is a very long process, but we hope that yeast will help us, for the first time, fully describe what happens when the human body is decrepit.
If you manage to slow down aging, will it not lead to the fact that body cells of such an "immortal" person will eventually lose their ability to divide or become predisposed to the development of cancer?
- It seems to me that such a problem will not arise, since the rejuvenation of cells should lead to the fact that they retain their normal ability to divide. So far, our experiments show that all experimental methods of life extension not only increase the life span of animals, but also allow them to remain healthy much longer than usual.
This is the main goal of all my work - I do not care if I can make a person immortal, but at the same time infinitely sick. I would like people to stay healthy as long as possible, and if they manage to live longer, it will be a pleasant, but additional bonus.
Relatively recently, your colleagues from California were able to rejuvenate mice by temporarily turning on genes associated with the work of stem cells in their cells. Will not such "extreme" forms of struggle against old age provoke protests from politicians and the public, and can they be applied in practice in the foreseeable future?
- It seems to me that both this approach and many other methods of rejuvenation need to be tested in experiments on volunteers, but most of them are not yet ready to work with humans. Beyond ethical reasons, there are a number of technical issues that make it extremely difficult to transfer test results in mice and other rodents to humans.
Already, there are drugs, as well as various diets and lifestyles, which should greatly affect the rate of human aging. And if we manage to prove that these simple and relatively safe measures really prolong life, then, it seems to me, the public will be ready for more daring steps.
Of course, someone may not like the manipulation of genes and the work of cells, but how, in fact, is the treatment of cancer and the fight against aging different? From the point of view of medicine, age and aging are the main risk factors in the development of malignant tumors and a number of chronic diseases, and therefore, victory over aging will mean victory over them.
In fact, an anti-aging drug will also work as a means to prevent cancer, heart disease and other health problems that are taking the lives of most older people today. It is unlikely that anyone will have ethical claims against us if they understand this connection.
Moreover, the fight against aging will help us solve or postpone the main problem of the future, the "gray tsunami", the real economic end of the world, caused by the fact that today there are fewer young people on Earth and more and more elderly people who need to pay a pension and for whom look after.
