Japan has the worlds oldest population, with 28 percent of all citizens comprising of elderly people above the age of 65. The secret to longevity lies not only in their healthy diet and lifestyle choices, but is influenced by a specific set of genes. Yes, the reason the country has 146 people over the age of 110 (referredto as supercentenarians) is simply good genes. This factor enabled them to stave off cancer and other deadly diseases for more than a century.

A new study conducted by the RIKEN Center for Integrative Medical Science (IMS) and Keio University School of Medicine in Japan sought to understand the genetics behind aging in supercentenarians by analyzing single-cell RNA sequencing.In the paperthat was published in the journal Proceedings of the National Academy of Sciences, the scientists investigated the immune cells of seven supercentenarians and made comparisons to the five subjects with ages between 50 and 80 years.

Researchers looked at 41,208 cells altogether from the elders with ages over 110, and 19,994 cells in the control group. The two cells part of the bodys immune response, which are B-cells and T-cells, were studied.It was found that B-cells had a lower count in the supercentenarians, while T-cells were at the same number in both groups.

However, the major finding was that supercentenarians had more of a particular subset of T-cells, namely CD4 T-cells that are capable of killing harmful cells, which wasonly possible by cytotoxic CD8 T-cells until then. In fact, 80 percent of the T-cells were composed of CD4 markers, whereas 10 to 20 percent of the T-cells had the marker in people of ages between 50 and 80.

The secret to aging may lie in your genes. Photo courtesy of Pexels

Since T-cells with CD8 markers are known to be cytotoxic, this means the CD4 markershad changed to acquire the new function, as per the researchers. This was not the case with the relatively younger subjects, this was the single most unique genetic characteristic of supercentenarians.

"This research shows how single-cell transcription analysis can help us to understand how individuals are more or less susceptible to diseases. CD4-positive cells generally work by generating cytokines, while CD8-positive cells are cytotoxic, and it may be that the combination of these two features allows these individuals to be especially healthy," Piero Carninci, IMS Deputy Director, said.

To understand the unusual phenomenon better, the researchers further studied the cells of two older participants, only to find another interesting fact about the CD4 T-cells: They had descended and multiplied from a single ancestral cell.

"We believe that this type of cells, which are relatively uncommon in most individuals, even young, are useful for fighting against established tumors, and could be important for immunosurveillance. This is exciting as it has given us new insights into how people who live very long lives are able to protect themselves from conditions such as infections and cancer," Carninci added.

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The Secret To Longevity Could Be Genetics - Medical Daily