Researchers have tried to explain the action of drug, Rapamycin, an antibiotic and immunosuppressant, to emulate the ability of dietary restriction in helping animals to live both longer and healthier.
Researchers suggest that a combination of rapamycin and another drug to offset that increase in insulin resistance might provide the benefits of this medication without the unwanted side effect.
Viviana Perez, an assistant professor in the Department of Biochemistry and Biophysics in the OSU College of Science, said this could provide a way not only to increase lifespan but to address some age-related diseases and improve general health, asserting that they might find a way for people not only to live longer, but to live better and with a higher quality of life.
Age-related diseases include many of the degenerative diseases that affect billions of people around the world and are among the leading causes of death: cardiovascular disease, diabetes, Alzheimer's disease and cancer.
Laboratory mice that have received rapamycin have reduced the age-dependent decline in spontaneous activity, demonstrated more fitness, improved cognition and cardiovascular health, had less cancer and lived substantially longer than mice fed a normal diet.
Called mTOR in mammals, for the term "mammalian target of rapamycin," this pathway has a critical evolutionary value - it helps an organism avoid too much cellular expansion and growth when energy supplies are insufficient. That helps explain why some form of the pathway has been conserved across such a multitude of species, from yeast to fish to humans.
A big drawback to long-term use of rapamycin, however, is the increase in insulin resistance, observed in both humans and laboratory animals. The new research identified why that is happening. It found that both dietary restriction and rapamycin inhibited lipid synthesis, but only dietary restriction increased the oxidation of those lipids in order to produce energy.
The new findings have been published in the Journals of Gerontology: Biological Sciences.