The risk of natural death increases with age. But aging is not a continuous phenomenon. A study in flies shows that this takes place in two different phases. And it is even possible to postpone the fatal phase by acting on certain genes.
Time affects individuals differently. A study published in the journal Aging cell, confirms this in an astonishing way. It was coordinated by CNRS researcher Michael Rera, head of the UteLife team (Paris Cité University, Inserm). The geneticist dissects the phenomena associated with aging by studying the tiny Drosophila “vinegar fly”, that penetrates ripe fruit.
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In 2012, Michael Rera showed that we can predict death in flies. “They live for about fifty days, but we can identify individuals with a life expectancy of just three days. » And this, regardless of the age of the insects, ten or forty days! The experiment involved turning their food blue. The next day, some flies lost their usual orange-brown color and turned blue: they will soon die. The dye is non-toxic; it is the intestine that at some point becomes permeable. Aging is therefore a phenomenon that takes place in two different phases. “separated by a more or less abrupt phase”.
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The new study shows that “The signs of aging are mainly found in bluebottles, i.e. in the late phase of life” . These markers are inflammation of multiple organs and “a strong decrease in locomotor capacity, while this effect of time is not observed in flying in the first phase.” The flies (blue) at the end of the course “They also have far fewer molecules that store energy.”
Researchers studied insect genes. Genes are present in all cells and perform various roles, particularly in rebuilding and regulating the body over time. In humans, for example, certain genes are responsible for the production of proteins (keratin), on which the quality of hair and skin depends. Others regulate the immune response during an infection.
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The research shows that the expression of various genes differs greatly between the two life stages. Young or old, first-stage flies have genes that are expressed in much the same way. Then everything changes once we enter phase 2! “Contrary to what we thought, the level of gene expression is linked to biological age, not chronological age”, summarizes Michael Rera.
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Lifespan increased by 10%
To verify this, scientists looked at three fly genes. “By altering the expression of these genes, we have delayed entry into late life. The lifespan of individuals then increased by more than 10%” .
In other species, such as mice and zebrafish, the UteLife team has shown that individuals at a late stage of life can also be identified. Is this possible in humans and do we age in two phases? “We cannot conclude at this time, specifies Michael Rera. Even if epidemiological data on age-related pathologies show that biological changes are detected several years before death. » If this late stage of life exists among us, it continues “six to eight years” about. Can we adjust the expression of our genes, like in flies, to live longer? “It is not technically feasible and I do not know whether it is desirable,” answers the geneticist.
After these discoveries, we can imagine diagnosing our biological age, treating ourselves accordingly. Will therapies delay entry into home life? This research raises staggering new questions about aging.