Age is the most important risk factor for diseases affecting the Western world, and slowing age-related degeneration would greatly improve the quality of human life. In rodents, caloric restriction (CR) extends lifespan by up to 50%. However, attempts to mimic the effects of CR pharmacologically have been limited by our poor understanding of the mechanisms involved. SIRT1 is proposed to mediate key aspects of CR, and small molecule activators may therefore act as CR mimetics. The polyphenol resveratrol activates SIRT1 in an in vitro assay, and produces changes that resemble CR in vivo, including improvements in insulin sensitivity, endurance, and overall survival in obese mice. However, resveratrol has numerous other targets that could contribute to its health benefits. Moreover, unlike bona fide CR, resveratrol has not been shown to extend lifespan in lean mice. Overexpression of SIRT1 or treatment with a novel activator is sufficient to improve metabolism, supporting the idea that resveratrol could act through this pathway. However, the poor phenotype of SIRT1 null mice has thus far precluded a more definitive test.
© 2011 New York Academy of Sciences.