To rejuvenate, American millionaire Bryan Johnson is injected with his son’s plasma.
Staying young is one of the obsessions of the time, expressed in the media and on social networks which propagate and amplify the desire for youth through advertising campaigns financed by the cosmetics sector. This grew by 15% last year and currently represents more than the turnover of Apple, Tesla and Coca-Cola combined. But, fortunately, the industry is not the only one interested in the age of our arteries. Medicine and the academic world have initiated research in this area for decades. Age is synonymous with illnesses. To slow down the first is to prevent the appearance of the second. Jean-Marc Lemaitre is director of research at the National Institute of Health and Medical Research (INSERM) and co-director of the Montpellier Institute of Regenerative Medicine and Biotherapy. His work focuses on understanding the mechanisms of aging and strategies for restoring the functionality of tissues and organs altered by time. While in Brussels, he presents his latest book Deciding on your age.
Why do we age?
JEAN-MARC LEMAITRE – Because our cells age. This is the hypothesis that my team and I have adopted since 2006 when we began working on aging. We had to see what was happening in our cells. Previous studies carried out on twins showed that our genetic heritage was responsible for 25 to 30% of aging. The latest research carried out on both siblings and descendants shows that this percentage is reduced to 15%. Which means that, overall, 85% of the factors depend on the way we live.
Turn your biological clock back three years
You have identified 12 markers of cellular aging. What are they?
It has long been considered that nine types of alterations are characteristic of the aging of our cells, affecting the body at different levels. Today, we have, in fact, twelve of them. Which can be grouped into two main categories: the least cellular renewal (senescence) and epigenetic factors. Before 1960, the idea prevailed that vertebrate cells could multiply infinitely. In 1961, it was shown that cultured cells from human fetuses could only divide a limited number of times. After a few months of cultivation, their multiplication slows down, then stops. After stopping their multiplication, the cells replicate. During the replication stage by an enzyme complex, it is unable to copy the last nucleotides at the end of the chromosomes (the telomeres). Telomerase, an enzyme that can compensate for telomere shortening, is no longer expressed in the majority of our tissues. But in mice we were able to make it express itself again and stimulate tissue regeneration impaired with age to increase longevity. Epigenetic factors are, broadly speaking, factors external to our cells. Among them are exposure to the sun, exposure to aggressive agents, diet, sedentary lifestyle, pollution and even smoking.
Multiple copies of photocopies, would that be a correct image to describe senescence?
At the end of the last century, we had a comparable metaphor. We were talking about copies of VHS videos. After the tenth copy, the image was more pixelated and much less sharp. The signal is less clear. To complete the metaphor, when we do cellular reprogramming (using the stem cell of a tissue), it’s a bit like asking an AI to return to the original image.
Can we adopt daily behaviors to “reprogram” our cells, to make their replications more faithful?
First, we have to measure where we are. Where our biological clock is in relation to our chronological clock. Three drops of blood are enough. We can identify the level of 10,000 circulating proteins and therefore then look at those which are correlated with chronological age and influence the equation with physiological and biological parameters. Basically, knowing why we age and therefore, what factors to act on. Today, we know how to measure all of that. We experimented with this in a pilot study on a group of people who were put through a program for eight weeks. We are switching to a Mediterranean diet and a physical exercise program when most were sedentary. We organize yoga sessions, meditation to reduce stress, some phytonutrients, etc. Sleep, environment, optimism. After eight weeks, the blood was tested again. The biological clock had gone back three years and five months…
Rejuvenate mice
The latest research in rejuvenation is embodied by billionaire Bryan Johnson…
Yes, in particular one of them: blood transfusions. This American multimillionaire is injected with his son’s plasma and injects his father with his own. In reality, these are experiments that date back more than a century, and that we also carry out in my laboratory. Young mice are connected to old mice via the bloodstream. We realized that the old mouse was getting younger and, conversely, the young one was getting older. In fact, in this mouse model, it was shown that it was possible to stimulate impaired muscle regeneration and stem cells, restore the epithelium at the level of olfaction, impaired spatial memory, and that we were even able to restructure the heart which was dilated with age, and to recover the expulsion function. There are therefore factors in young blood which allow us to stay young, but also to rejuvenate.
The “mouse” model has been applied to humans…
Yes, in the United States, where companies have been created and are carrying out clinical trials on humans, where Bryan Johnson presents himself in a way that borders on anticipation films. But where it is interesting is that we are in the process of identifying the circulating factors that are important. There is one, for example, which already does a lot of things: GDF11 is a molecule which helps restructure the heart. It’s just a molecule, we do genetic engineering, we synthesize it like a drug, we can inject it… This could help to rejuvenate cardiac function and prolong healthy life in humans. There have not yet been any clinical trials, but “transfusion” research is typically that. Identifying this entire range of circulating factors capable of rejuvenating our cells, synthesizing them, injecting them as drugs… This would prevent many diseases linked to aging. Thanks to these new drugs, we will age healthier.
In 20 years, cellular reprogramming
What is the time horizon for these drugs that will make us rejuvenate?
We already do it. We are trying to reposition a certain number of drugs that are already on the market for other diseases. And we realized that they played a role, that they slowed down aging in general. Metformin, rapamycin, statins… Molecules that are given for diabetes, as immunosuppressants or against cholesterol. For rejuvenation, it’s not for now. We will market senolytics – molecules that destroy senescent cells – in ten years. The same for the syntheses of GDF11 and other circulating factors. And cellular reprogramming is twenty years away.
What do you take or apply in your life?
I eat Mediterranean. I do physical activity and intermittent fasting. I take metformin. All the researchers who work on aging do intermittent fasting and take metformin…
One day all immortals?
No. Biological immortality is impossible. The limit is around 125 years. But with all the technological developments that are taking place, reaching that age in good health, I think it’s a realistic goal.
