Every year when people say "happy birthday" to you, you are one year older than yesterday. Birthdays determine how old you are, which you cannot change. But it may be possible to change your biological age.
Epigenome marks your biological age
Biological age can be measured by examining epigenome in your DNA. Epigenome is the complete description of all the chemical modifications to DNA and histone proteins that regulate the expression of genes within the genome.
During the course of your life, the pattern of epigenome changes and tracks your biological age, which can lag behind or exceed your chronological age (how many birthdays you've had).
People all want to reverse their aging process, and the resent study published in the journal Aging Cell shows first hint that reversing "biological age" may become possible.
About the study
In the one-year trial, nine healthy white men aged between 51 and 65 took a cocktail of three drugs — one common growth hormone and two diabetes medications — to see whether they would slow down their biological clock.
The trial targeted the thymus gland, a small gland in the chest that matures white blood cells to help the body fight infections and cancers. Previous studies have shown that the gland starts to shrink after puberty.
Evidence from animal and some human studies shows that growth hormone stimulates regeneration of the thymus gland and promotes diabetes, that's why the trial included one common growth hormone and two diabetes medications, dehydroepiandrosterone (DHEA) and metformin.
About the results
The results were astonishing:
—The participants regained 2.5 years of biological age on average.
—Seven participants regenerated thymus tissue and showed a rejuvenated blood-cell count.
—Six participants had persisted effect six months after stopping the trial.
The results surprised even the trial organizers. "I'd expected to see slowing down of the clock, but not a reversal," said geneticist Steve Horvath, who conducted the analysis. "That felt kind of futuristic."
Horvath is quite excited about the future. "Because we could follow the changes within each individual, and because the effect was so very strong in each of them, I am optimistic," he said.
Cancer immunologist Sam Palmer also said this "has huge implications not just for infectious disease but also for cancer and aging in general."
Although a larger study is still needed as some scientists pointed out that the trial was small in scope and did not include a control arm, regenerating the thymus may be useful in the future to protect against common age-related diseases, such as cancer and heart disease.