Efforts to extend the human lifespan, or in more exotic cases – even to achieve immortality, have recently been rejuvenated by a small clinical trial which demonstrated that the body’s “epigenetic clock” which measures a person’s biological age might be amenable to successful pharmaceutical manipulation.
In the trial, published on 5 September in the journal Aging Cell, nine healthy male volunteers (ages 51 to 65) were provided with carefully calibrated doses of growth hormone and two common diabetes medications for one year.
At the end of the intervention, the subjects were found to have shed 2.5 years off their biological ages and saw noticeable improvements in immune function – an outcome which surprised even the authors of the study themselves.
“I’d expected to see slowing down of the clock, but not a reversal,” said geneticist Steve Horvath of the University of California, Los Angeles, who performed the genetic analysis. “That felt kind of futuristic”.
A key reason for why the results of the study were surprising is that it was primarily designed to see whether growth hormone could be administered in humans without adverse effects to restore tissue of the thymus gland – essential for the production of immune cells – which becomes increasingly suppressed after puberty.
Since growth hormone is known not only to stimulate the regeneration of the thymus, but also to promote the development of diabetes, test subjects were also given dehydroepiandrosterone (DHEA) and metformin to counteract any negative effects.
An analysis of blood samples collected during, as well as MRI images taken prior and after, the trial showed increased blood-cell count and rejuvenated thymus tissue in all nine participants.
Following the conclusion of the trial, Horvath was approached by the geneticist Gregory Fahy to examine the subjects’ epigenetic clocks, finding robust effects which were maintained at six month follow-up.
“Because we could follow the changes within each individual, and because the effect was so very strong in each of them, I am optimistic,” said Horvath.
Since the initial trial was very small, making it preliminary, Intervene Immune is already planning to conduct a larger study composed of people of different ethnicities, genders, and age groups.