There is no more unjust executioner than time. Mute, what’s more. He attacks some, spares others, without warning. What will he do with the vitality and tone of our younger years when they are behind us? Will we age more or less quickly than others? To find out and help us better defend ourselves, more and more academic laboratories are developing “biological clocks”, markers of the real age of our body, often different from our chronological age.
At the beginning of December, a significant breakthrough in this area made the front page of the prestigious scientific magazine Nature. A team of American scientists has shown that it is possible to evaluate the aging of each of our organs. These specialists succeeded in measuring proteins specific to the heart, brain, intestines and eight other parts of our bodies in the blood of more than 5,600 adults. Proteins that have the particularity of changing with age. In every fifth participant, signs of accelerated aging of at least one organ were detected. For the authors, this technique could ultimately help to implement preventive measures and control their effects. Enough, perhaps, to delay the consequences of the passage of time.
In recent years, many other tests have appeared in research laboratories, before a multitude of start-ups took them up. To hear them, they would indicate the “aging stage of our cells”, a much more interesting indicator than the simple count of blown out candles. In the United States, it is already possible to have it delivered, thanks to services like Tally Health. For a few hundred dollars a month, the company provides a collection kit to be done every quarter. The company then takes care of the analysis.
Tally Heath is the entrepreneurial counterpart of the activities of David Sinclair of Harvard University in the United States, a pioneer in research on aging and longevity. By wanting to understand why our cells wear out more or less quickly and how to combat this phenomenon, a booming scientific field, researchers like David Sinclair discovered that certain elements could testify to the decline of our organisms, regardless of the passage of time. . “By condensing them, we obtain these biological clocks. All kinds of them have been developed in recent years, depending on the cellular mechanisms explored,” rejoices Yves Rolland, doctor and researcher at the brand new HealthAge university hospital institute in Toulouse.
Experimental tools…
In January 2023, a study published in cell included more than twelve different types of biological clocks, based for example on the accumulation of mutations in genes or on the rate of inflammation. So many witnesses to the work of time on our cells. According to the authors of the analysis, they are “interconnected with each other” and linked to different clinical manifestations of age, such as wrinkles or loss of cerebral and physical abilities.
Certain biological clocks function like a countdown for our body, programmed at birth by the rules written in the genetic heritage. Others result from an age-related deterioration in function, which we have learned to decipher. “One of these tests counts, for example, methylation, that is to say the number of methyl groups attached to DNA. They serve to cut off gene expression but accumulate erratically over time, which is one factor of aging among others,” explains Coleen T. Murphy, biologist at Princeton University (New Jersey). .
Another method: count the “transcriptions”, the number of cellular copies. They are limited in number. Once the countdown is complete, the cell kills itself. Scientists also count genetic errors that accumulate over time. There are more and more of them because disruptions occur. They also study how proteins are ordered within the cell (proteostasis) or telomeres, which are found at the ends of chromosomes and whose size decreases over time.
…tomorrow in our bathrooms?
New stars of the anti-aging scientific conferences this year, from Longevity Summit from the Buck Institute to Aging Research and Drug Discovery Meeting, an important meeting in the pharmaceutical industry, these technologies arouse as much enthusiasm as questions. “How useful will they be to the general public? How relevant are they? How are the different measured data related to each other?” list for example David Furman, associate professor at the Buck Institute for research on aging, researcher at Stanford University (United States) and member of the scientific council of Parfums Dior Reverse Aging.
If certain biological clocks are already on the market, including in France where the avant-garde Zoī clinic has, for example, integrated them into its medical analyzes to optimize life expectancy, none of these solutions is proven in reality. at this stage reliable enough to draw medical conclusions. “These tools are especially useful for fundamental research, because they help to quantify the effects of our manipulations on the cells themselves, which has enabled numerous discoveries,” explains Coleen T. Murphy from her laboratory in Princeton where she arrives , like David Sinclair and many others, to double the life expectancy of worms.
Potentially reversible clocks
However, some researchers believe that they are already mature enough to use them in human trials to verify the anti-aging effect of certain molecules, which is more difficult to detect than for pathologies (Alzheimer’s, Parkinson’s) where the disorders occur. see more. Dozens of substances are currently being studied. By preventing the effects of aging within the cells themselves, they could help us live a long life in good health, like those centenarians who show no other apparent signs of their decline than the wrinkles that populate their faces. In animals, thanks to these cures, hair grows back and memory returns.
In 2019, a team led by Greg Fahy and Steve Horvath, two renowned biologists, used methylation to test a hormone on humans, paving the way for this type of experimentation. The biological clocks used were designed by Steve Horvath himself, scientific pillar of the Altos company, one of the most advanced in the sector. The biological age calculated by the clock improved with the administration of the hormone. Experience suggests that it is therefore possible to act on these indicators in humans. Would this result in “rejuvenation”? The mechanisms of aging are too numerous to be certain.
The fact remains that, according to technophiles, these clocks will eventually invade our bathrooms and medical offices. Powered by AI, compiled, compared with each other and with other indicators, they will make it possible, as an entrepreneur says, to monitor and adjust a form of personalized aging hygiene. And to fight age before it hits too hard. A sign that these scientists are perhaps not wrong, more and more researchers are already integrating these markers into their algorithms. The beginning of a new era.
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