Scientists may have stumbled on a way to reverse the body's biological age. The discovery was made during a small clinical study in California and the researchers said even they were surprised by the results.
"I’d expected to see slowing down of the clock, but not a reversal," said geneticist Steve Horvath at the University of California, Los Angeles, who led the study, Nature reports.
For the trial, nine healthy volunteers were given a mix of growth hormones as well as two types of diabetes medication. The team then analyzed marks on the participants' genomes and found they had shed an average of 2.5 years in biological ages and also showed signs that their immune systems had undergone rejuvenation.
Central to the findings is the "epigenetic clock," which tracks and predicts a person's biological age. Scientists can track molecular aging through DNA analysis. For the trial, Horvath assessed each patient's biological age with four different epigenetic clocks and the findings were all similar.
"This told me that the biological effect of the treatment was robust," he said. "What’s more, the effect persisted in the six participants who provided a final blood sample six months after stopping the trial."
Cancer immunologist Sam Palmer at the Herriot-Watt University in Edinburgh said the discovery had "huge implications" for infectious disease as well as cancer and ageing but researchers cautioned that the findings only reflected a small study and more research was needed.
Horvath, however, said he felt the research was promising.
"Because we could follow the changes within each individual, and because the effect was so very strong in each of them, I am optimistic."
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