Biological Aging May Be Reversible

9 male participants between the ages of 51-65 were given a cocktail of two diabetes medications (DHEA and metformin) and a growth hormone for one year which the scientists were testing in hopes of regenerating the thymus gland. Analysis showed that on average the participants had lost 2.5 years on their epigenetic clock measured by examining markers in their genomes, and their immune system showed signs of rejuvenation. 

"I’d expected to see a slowing down of the clock, but not a reversal. That felt kind of futuristic." UCLA researcher Steve Horvath told Nature. 

Although promising, these findings are preliminary, the study was very small, and did not include controls, meaning more research is required. Should additional studies confirm these findings the impacts on healthcare and human relationships with aging as a whole could be extreme. 

The epigenetic clock is measured by a record of changes to DNA, 4 different measures were looked at for each of the participants which were all found to have reversed significantly. The purpose of this trial was to test whether a growth hormone could restore tissue in the thymus gland, which starts to shrink after puberty and becomes clogged with fat; regeneration may be useful in those with an underactive immune system. 

Six months after the trial blood samples were provided by 6 of the participants for follow up, analysis showed that the effects had remained the same. The team is very optimistic for future testing given how strong the effect was in each of the participants.

"This told me that the biological effect of the treatment was robust. 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.

“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.”

A larger study is in the works involving more diverse participants in regards to gender, age, and ethnicity and it will test all three drugs: DHEA, metformin, and growth hormone, independently to determine the specific effects. 

Growth hormone has been shown to stimulate regeneration in the thymus, but it can cause diabetes, hence why diabetes medications were included in the cocktail; and metformin is already being investigated for the potential to protect against age related diseases. DHEA is being studied for the ability to slow the aging process, improve performance, enhance libido, promote weight loss, and bolster the immune system. The cocktail ingredients may contribute separately to the biological effect on aging through unique mechanisms, which will be explored in future studies. 

“This has huge implications not just for infectious disease but also for cancer and ageing in general,” says cancer immunologist Sam Palmer at the Herriot-Watt University.