Alison Abbott in Nature:
A small clinical study in California has suggested for the first time that it might be possible to reverse the body’s epigenetic clock, which measures a person’s biological age. For one year, nine healthy volunteers took a cocktail of three common drugs — growth hormone and two diabetes medications — and on average shed 2.5 years of their biological ages, measured by analysing marks on a person’s genomes. The participants’ immune systems also showed signs of rejuvenation. The results were a surprise even to the trial organizers — but researchers caution that the findings are preliminary because the trial was small and did not include a control arm.
“I’d expected to see slowing down of the clock, but not a reversal,” says geneticist Steve Horvath at the University of California, Los Angeles, who conducted the epigenetic analysis. “That felt kind of futuristic.” The findings were published on 5 September in Aging Cell1. “It may be that there is an effect,” says cell biologist Wolfgang Wagner at the University of Aachen in Germany. “But the results are not rock solid because the study is very small and not well controlled.” The epigenetic clock relies on the body’s epigenome, which comprises chemical modifications, such as methyl groups, that tag DNA. The pattern of these tags changes during the course of life, and tracks a person’s biological age, which can lag behind or exceed chronological age.