- Researchers investigate aspects of human aging in a small study.
- They found evidence that the biological age of a person can be reversed.
- The results seem promising and researchers will try to replicate them in an appropriately large follow-up study.
Population aging is an increasingly important problem in developed countries, bringing with it several medical, psychological, economic, social and political issues.
Over the past few years, numerous biomedical methods to halt the aging process have been examined in animal models. However, none of them has been able to provide any evidence that systemic aging can be reversed.
Recently, researchers at the University of California conducted a small clinical trial — TRIIM — to investigate aspects of human aging. Surprisingly, they found evidence that the body’s epigenetic clock (which measures the biological age of a person) can be reversed.
The objective of this trial was to analyze the possibility of using rhGH (recombinant human growth hormone) to prevent or reverse signs of immunosenescence (the gradual deterioration of the immune system due to natural age advancement) in a population of 51- to 65-year-old putatively healthy men.
In this study, 9 healthy participants took a cocktail of 3 common drugs (2 diabetes medication and 1 growth hormone) for one year. Researchers analyzed the marks on participants’ genomes and found that on average they shed 2.5 years of their biological ages. In fact, their immune systems also showed signs of rejuvenation.
Although the results seem promising, researchers cautioned that the outcomes are preliminary as the trial was small and not well-controlled.
Biomarkers of Aging
This trial was specially designed to examine whether human tissue could be restored in the thymus gland by using growth hormone. It is a specialized primary lymphoid organ of the immune system located in the chest between the lungs and the breastbone.
This where white blood cells are matured and become specialized T cells, helping the body to fight diseases and infections. After puberty, however, the size of this gland starts shrinking and gradually gets clogged with fat.
Some previous studies showed that growth hormone in animals, including humans, can stimulate regeneration of the thymus. But it can also increase diabetes levels, and thus researchers used two popular anti-diabetic drugs in the treatment cocktail.
Reference: Nature | DOI:10.1111/acel.13028 | Aging Cell
The team started the TRIIM trial (short for Thymus Regeneration, Immunorestoration and Insulin Mitigation) in 2015 after getting approval from the US Food and Drug Administration.
During the treatment period, researchers took blood samples of participants and analyzed them via different methods. All tests showed that blood cell count in each participant was rejuvenated.
They also used MRI to study the thymus gland’s composition at the beginning and end of the trial. They discovered that accumulated fat in 7 participants had been replaced by regenerated thymus tissue.
In order to precisely evaluate each participant’s biological age, researchers used 4 different epigenetic clocks. In each case, they found a significant reversal. Furthermore, the biological effect of the treatment persisted in 6 participants for 6 months.
The team is also testing the drug for its capability to protect against natural age-related disease, including heart disease and cancer. The 3 drugs used in this study could contribute separately to the biological aging effect through unique techniques.
Researchers will try to verify the present outcomes by replicating them in an appropriately powered follow-up study. They have already planned a larger study that will include both men and women of different age groups and ethnicities.