Thesirtuinas, proteins to which the ability to significantly increase the life expectancy of a certain number of organisms was attributed,they do not actually affect the longevity of living things, according to a new study published in the journalNature.
The sirtuins had beenpreviously related to aging and longevity in yeast, nematode worms, and fruit flies, organisms used as models for the biology of human aging. Researchers had shown that when the body’s genes produce excess sirtuins, their lifespan is significantly extended, in nematodes by as much as 50 percent. Such was the stir caused that the sirtuin-producing gene wasnicknamed “longevity gene”. After these results were published, a series of anti-aging creams containingresveratrol – a component of plant origin found in red wine – with the supposed objective of activating the production of sirtuins.
But the new study, conducted by British, Hungarian and American researchers, has debunked these ideas. The scientists first examined two different strains of nematode worms that had been genetically engineered so that the sirtuin-producing gene was hyperactive. Unsurprisingly, these worms outlived the control worms (that is, the worms that had not been genetically engineered). However, after precautions were taken to ensure that the only difference between the control worms and the test worms was the elevation of sirtuin levels, the effect on longevity disappeared. This implies thatother genetic factors promoted the longevity initially observed. In one of the two original strains, the researchers identified a mutation in a gene involved in the development of neurons.
The researchers next examined a transgenic version of the fruit fly,Drosophila melanogaster, in which sirtuin levels rose. This transgenic model had been the subject of previous research that seemed to show that over-activation of sirtuins in the fruit fly gave it significant longevity. The researchers were able to show again, through the results of this new study, thatother genetic factors, unrelated to sirtuin genes, are the real cause of longevity.
According to David Gems, researcher at the Institute for Healthy Aging at University College London (UK) and co-author of the work, “these results are surprising.” “We have re-examined the main experiments linking sirtuins to longevity in animals and have found that their results do not hold up after rigorous scrutiny of sirtuins, which appear to have nothing to do with life span.” concludes.
