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.
The antiaging trial included two widely used anti-diabetic drugs, dehydroepiandrosterone (DHEA) and metformin.
For one year, nine healthy volunteers took a cocktail of three common drugs — growth hormone and two diabetes medications — and on average shed 2.5 years of their biological ages, measured by analysing marks on a person’s genomes. The participants’ immune systems also showed signs of rejuvenation.
Scientists construct epigenetic clocks by selecting sets of DNA-methylation sites across the genome. In the past few years, Horvath — a pioneer in epigenetic-clock research — has developed some of the most accurate ones.
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. White blood cells are produced in bone marrow and then mature inside the thymus, where they become specialized T cells that help the body to fight infections and cancers. But the gland starts to shrink after puberty and increasingly becomes clogged with fat.
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.
The Thymus Regeneration, Immunorestoration and Insulin Mitigation (TRIIM) trial tested 9 white men between 51 and 65 years of age. It was led by immunologist Gregory Fahy, the chief scientific officer and co-founder of Intervene Immune in Los Angeles, and was approved by the US Food and Drug Administration in May 2015. It began a few months later at Stanford Medical Center in Palo Alto, California.
In 1986 Fahy read a study in which scientists transplanted growth-hormone-secreting cells into rats, apparently rejuvenating their immune systems. No one seemed to have followed up on the result with a clinical trial. In 1996, he treated himself for a month with growth hormone and DHEA, and found some regeneration of his own thymus.
In the TRIIM trial, the scientists took blood samples from participants during the treatment period. Tests showed that blood-cell count was rejuvenated in each of the participants. The researchers also used magnetic resonance imaging (MRI) to determine the composition of the thymus at the start and end of the study. They found that in seven participants, accumulated fat had been replaced with regenerated thymus tissue.
Horvath used four different epigenetic clocks to assess each patient’s biological age, and he found significant reversal for each trial participant in all of the tests.
The effect persisted in the six participants who provided a final blood sample six months after stopping the trial.
Written By Brian Wang, Nextbigfuture.com