"First hint that body’s ‘biological age’ can be reversed," screamed the headline of Nature.com, an online scientific articles website. In a small trial, drugs seemed to rejuvenate the body’s ‘epigenetic clock’, which tracks a person’s biological age, it reassured.
According to the report in Nature.com, 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. By testing the blood samples from the said clinical trial designed to reverse aspects of human ageing, scientists found a significant reversal in their epigenetic ages.
What was the experiment?
1. The study was titled "Thymus Regeneration, Immunorestoration and Insulin Mitigation" or TRIIM trial.
2. The TRIIM trial tested 9 white men between 51 and 65 years of age.
3. First, the researchers decided upon which 9 persons to pick from the many healthy volunteers.
4. Then, the chosen ones were given a cocktail of three common drugs — growth hormone and two diabetes medications.
5. Findings suggest that on average, each of them shed 2.5 years of their biological ages.
6. These results were arrived at by measuring and analysing marks on a person’s genomes.
7. The participants’ immune systems also showed signs of rejuvenation.
8. The TRIIM study was carried out in 2019 and was led by immunologist Gregory Fahy, the chief scientific officer and co-founder of Intervene Immune in Los Angeles.
9. The trial was approved by the US Food and Drug Administration in May 2015.
10. It began a few months later at Stanford Medical Center in Palo Alto, California.
Thymus Gland on the radar:
According to the report in Nature.com, the results were a surprise even to the trial organisers — 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 Cell.
“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 latest trial was designed mainly to test whether growth hormone could be used safely in humans to restore tissue in the thymus gland. The gland, which is in the chest between the lungs and the breastbone, is crucial for efficient immune function.
What the Thymus Gland does:
White blood cells are produced in the bone marrow and then mature inside the thymus, where they become specialized T cells that help the body fight infections and cancers. In simple words, a type of lymphocyte that develops in the thymus gland, T-cells are essential to human immunity. As we age the thymus gland starts to shrink after puberty and increasingly becomes clogged with fat.
The epigenetic clock is an age predictor based on DNA methylation levels. It is dependent on the body’s epigenome, which is a complete description of all the chemical modifications—such as methyl groups—that tag DNA and histone proteins.
The pattern of these tags changes throughout the course of a person’s life, and tracks their biological age, which does not necessarily coincide with their chronological age.
According to the researchers, additional studies need to be done on immunosenescence.
Evidence from animal and some human studies shows that growth hormone stimulates regeneration of the thymus. But this hormone can also promote diabetes, so the trial included two widely used anti-diabetic drugs, dehydroepiandrosterone (DHEA) and metformin, in the treatment cocktail.