Sarcopenia: the role of apoptosis and modulation by caloric restriction. (2008)

Abstract
The mechanisms of sarcopenia have been slowly unraveled and likely involve activation of apoptosis. It is hypothesized that caloric restriction may, in part, attenuate sarcopenia by affecting apoptotic signaling. The signaling pathways responsible for the execution of apoptosis in aging muscle and the modulation of these pathways by caloric restriction are discussed.

My Comments:
This was a review paper I found when following up on my recent blog describing the monkey study where they found a 30% reduction in calories resulted in less muscle fiber atrophy and loss due to age. This paper, though earlier, is a review attempting to explain why, describing caloric restriction as:

“the only nongenetic intervention known to slow the intrinsic rate of aging in mammals. Caloric restricting rodents 40% of ad libitum diet, while maintaining adequate nutrition, increases maximum lifespan 30-40%. Caloric restriction slows the progressive decline in widespread organ function and attenuates the onset of age-related diseases, such as cancer, diabetes, and Alzheimer disease. Caloric restriction also attenuates the decline in skeletal muscle function with age.”

They cited studies on rats, which were recently confirmed on primates and it seems that at least some of the benefit is the prevention/slowing of apoptosis also known as programmed cell death. Muscles cells, being cells, seem be among the many tissues that just survive better when you eat less. The gist of the paper is that apoptosis of muscle cells is documented to occur, there is a lot of research being done attempting to describe the exact mechanism, which as of yet is unknown. It was interesting to see that the earlier primate study I cited wasn’t a novel finding but rather confirming what had already been shown in other mammalian species. In other papers I have ordered and started to read on, calorie restriction and intermittent fasting for slowing nearly all aspects of aging are fascinating and something I expect I’ll be continuing to blog on, as though diet related, seems pretty relevant to physical therapy and just health in general.