Senescent Cells and Short Term Calorie Restriction

Researchers run short-term studies on calorie restriction because it's cheaper and faster than long-term studies. Fortunately some of the biological changes brought on by calorie restriction take place fairly rapidly, so this is still a way to learn something. Here is one of the results: "Recent evidence supports the contention that cellular senescence is associated with, and may even be a cause of age-related functional impairment. Senescent cells accumulate in multiple tissues with advancing age. Cellular senescence causes a variety of cell types to acquire a pro-inflammatory secretory phenotype that produce a variety of cytokines, chemokines, and extracellular matrix remodeling proteases that are associated with tissue destruction. Chronic presence of senescent cells can accelerate cancer progression, possibly because of this inflammatory secretory phenotype. Engineered deposition of senescent cells in a single organ, skin, can cause functional impairments in multiple organs similar to those occurring with aging. Finally, senescent cell accumulation in progeroid animal models is associated with dysfunction resembling that of aging. Caloric restriction attenuates processes that have been implicated in cellular senescence, including generation of reactive oxygen species (ROS), growth hormone/insulin-like growth factor-1 signaling, and inflammation. Does caloric restriction in fact reduce cellular senescence? [An] important study [found] short term dietary restriction in middle-aged mice is associated with decreased abundance of senescent cells in the liver (centrilobular hepatocytes) and intestine (crypt enterocytes)."

Link: http://www.impactaging.com/papers/v2/n12/full/100247.html