A group of scientists in California might have for the first time indicated that it is possible to turn back the aging clock like Benjamin Button did in the movie.
Summary of the study
The Thymus Regeneration, Immunorestoration and Insulin Mitigation (TRIIM) trial was led by immunologist Dr Gregory M. Fahy and began in 2015 at Stanford Medical Center in Palo Alto, California, just a few months after receiving trial approval from the US Food and Drug Administration.
The researchers lead by Dr. Fahy have serendipitously found evidence that suggests that recombinant human growth hormone (rhGH) can reverse epigenetic aging in humans. The study published in Aging Cell consisted of administering a combination of three drugs- growth hormone and two widely used diabetes medications ( dehydroepiandrosterone (DHEA) and metformin) – to ten nominally healthy volunteers aged 51-65 years. The volunteers were monitored over the course of a year. At the end of the year, the researchers found that seven of the volunteers had lost fat in their thymuses and that healthy tissue had regrown to replace it. The researchers also conducted epigenetic marker (methylation) testing on the volunteers, as well. They report that all of the volunteers experienced reverse epigenetic aging on an average of 2.5 years! The participants immune system also showed signs of rejuvenation.
There are obvious limitations to the study, because there are no control groups and the n numbers are very small. Further, reversal of epigenetic aging alone is not a good representation of the whole process of aging, however, it is still an accurate representation of age related disease risk available at the moment.
What has thymus got to do with aging?
The thymus is a gland in the chest that plays a crucial role in our immune system. It converts white blood cells to T cells and therefore plays an important role in immune response. Starting around the age of 1, our thymus begins to shrink and roughly halves in size every 16 years. As humans age, fatty deposits develop in the thymus and eventually it loses function over time and becomes mostly inactive during adulthood, a normal process called thymic involution. Our immune systems weaken along with it and declining thymus function has been linked to chronic diseases such as cancer.
Because of its essential role in our immune systems, rejuvenating the thymus is regarded as the ‘holy grail’ of preventing the immune decline in old age. In fact, restoring thymus function is such as prize that several organizations have been competing to be the first to do it. Previous research showed that injecting rats with growth hormone boosted their immune system. So the scientists wanted to test whether growth hormone could rejuvenate the thymus in humans. However since the hormone is also known to promote diabetes, they added two widely used anti-diabetic drugs into the mix.
What is epigenetics?
Epigenetics is heritable changes in DNA that do not modify the actual structure or sequence of the DNA. Chemical compounds (like methyl groups) that are added to single genes can regulate their activity; these modifications are known as epigenetic changes. Epigenetic changes are like molecular switches which can turn genes on and off. It is thought to be one explanation for how our environment and behaviour, such as our diet or smoking habit, can affect our DNA and how these changes may even be passed down to our children and grandchildren. Changes in DNA sequences can take several generations or millions of years to appear, whereas, epigenetic changes happen much faster and can occur throughout a person’s life.
The pattern of epigenetic changes we accumulate over the course of life is referred to as the epigenetic clock, which is an indication of a person’s biological age. Scientists construct epigenetic clocks by selecting sets of chemical compounds tagged to the DNA( DNA-methylation sites) across the genome.
Take home : In summary the scientists in this study found that their combination of growth hormones and diabetes medications reversed the epigenetic clock by 2.5 years along with improvements in their immune response.This is an interesting study because it is the first of its kind in humans. Although the size of the study is too small and the follow up period was only 1 year it is very promising and further research will only enhance our understanding of the process of aging if not reverse it!