Introduction
The life expectancy in many countries is projected to exceed 85 years by
2030.1 Globally, one quarter of the population is
expected to be in their sixties or older in 2050.2Nonetheless, the unprecedented longer life expectancy heralds a
staggering number of people living with age-related diseases and
considerable burdens on the social, economic, and healthcare systems
worldwide. There is a pressing need to combat the challenges posed by
age-related diseases and increase the health span of humans. However,
while age-related diseases can often coexist, current delivery of health
services and research efforts have continued to deal with the diseases
ineffectively in an insular fashion.3 In contrast,
mechanisms that account for the phenotypes of old age, such as impaired
metabolism, dysregulated immune profile, and abnormal DNA methylome,
have been shown to be the underlying determinants of many chronic
diseases.4 Therefore, modifying the mechanisms of
aging directly seems to be a more productive approach to fundamentally
curb the growth of chronic diseases.
Although aging has been traditionally considered an irreversible
process, encouragingly, a growing number of studies have indicated that
metformin and rapamycin, two drugs that have been used extensively to
treat type 2 diabetes (T2DM) and as an immunosuppressant respectively,
have the potential to stall aging and delay the onset of age-related
diseases. In this review, we survey a selection of articles about
metformin and rapamycin to give a glance of the anti-aging mechanisms
that have been studied with these two drugs and their extent of
effectiveness. Finally, remaining questions and concerns are highlighted
to guide future anti-aging research.