This, I think, is a great example of what emerges as a consequence of the distorting effects of regulation on medical research. Because it costs a ridiculous amount of money and time to push anything new past the regulators of the FDA, there is a great focus on generating very marginal new uses of drugs that have already been approved. Thus instead of forging ahead to build radically improved new technologies, things far better than mere drugs, much of the research community does nothing more than tinker with what is already known. This is a terrible thing to be happening at a time when the research community is finally shedding its inhibitions regarding the treatment of aging, and researchers feel able to speak openly about the goal of extending health human life spans. It is a stupendous waste of potential, and the cost is measured in lives lost.
Rapamycin, an antibiotic and immunosuppressant approved for use about 15 years ago, has drawn extensive interest for its apparent ability - at least in laboratory animal tests - to emulate the ability of dietary restriction in helping animals to live both longer and healthier. A big drawback to long-term use of rapamycin [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.
Rapamycin, by contrast, allowed a buildup of fatty acids and eventually an increase in insulin resistance, which in humans can lead to diabetes. However, the drug metformin can address that concern, and is already given to some diabetic patients to increase lipid oxidation. In lab tests, the combined use of rapamycin and metformin prevented the unwanted side effect.
"If proven true, then combined use of metformin and rapamycin for treating aging and age-associated diseases in humans may be possible. This could be an important advance if it helps us find a way to gain the apparent benefits of rapamycin without increasing insulin resistance. It could provide a way not only to increase lifespan but to address some age-related diseases and improve general health. We might find a way for people not only to live longer, but to live better and with a higher quality of life."