Rapamycin is a novel drug discovered in the soils of Easter Island, or Rapa Nui in the South Pacific Ocean. It is primarily known for its immunosuppressive benefits and is commonly used in the prevention of organ and tissue transplant rejection. Further studies about the isolated drug proved that it also has benefits as a metabolic initiator which effectively inhibits the capability of higher life forms to sense the availability of energy and initiate protein synthesis, cell growth and proliferation. This capability is the consequence of a biological pathway called mTOR (mammalian target of Rapamycin) in mammals. The said pathway is known to help the organism to avoid excessive growth and cellular proliferation in instances when available supplies are lacking or insufficient.
Dr. Viviana Perez, a biomedical science researcher and an assistant professor in the Department of Biochemistry and Biophysics in the OSU College of Science, explains that the mTOR pathway is the target and basis of dietary restriction in attempting to increase life span in animal studies. Restriction in food intake inhibits this pathway and has been shown to increase the lifespan of laboratory animals by 25-30 percent. Asians, who were known to eat less also statistically has a longer life expectancy.
This beneficial effect of dietary restriction has been found to be also exhibited by Rapamycin. This drug has been found to have a beneficial effect on slowing down the progression of old age-related disorders and exhibit significant impact even when used later in life.
The use of this drug however has a major setback, it being the development of insulin resistance with chronic use. This unfortunate side effect was observed to be evident in laboratory animals as well as human subjects.
A recent research conducted in the Linus Pauling Institute at Oregon State University sheds light on the mechanism by which this adverse effect of Rapamycin takes place. The study also discussed ways on how to prevent the occurrence of this drawback.
The study, which was published in the Journals of Gerontology: Biological Sciences suggests that Rapamycin can effectively exhibit its beneficial effects without the unwanted insulin resistance, through combination with a widely used anti-diabetic medication, Metformin.
Rapamycin was found to induce insulin resistance by allowing fatty acid build up which can eventually lead to Diabetes. Metformin, on the other hand, increases lipid oxidation which counters the accumulation initiated by Rapamycin.
The researchers concluded that if indeed Metformin can counter the side effect caused by Rapamycin, then the combination of both drugs raises the possibility of treating age-associated diseases and slowing the aging process.