A molecular pathway that is a key determinant of the aging process and could explain why eating less could extend lifespan has been found in a new study.
"We're getting closer and closer to a good understanding of how caloric restriction works. This study is the first direct proof for a mechanism underlying the anti-aging effects we observe under caloric restriction," said Tomas A. Prolla at the University of Wisconsin-Madison.
The team found that an enzyme known as Sirt3 has anti-aging effects in mammals, according to John M. Denu of UW-Madison's Wisconsin Institute for Discovery.
Under reduced-calorie conditions, levels of Sirt3 amp up, altering metabolism and resulting in fewer free radicals produced by mitochondria - structures inside cells that produce energy and that are the sources of highly reactive forms of oxygen known as free radicals, which damage cells and promote the effects of aging.
The work involved a mouse model that exhibits age-related hearing loss.
"Hearing loss is associated with the loss of specific cell types in the cochlea. And hearing loss is prevented through caloric restriction," said Prolla.
The team showed that elevated levels of Sirt3 protect cells from cell stress and death caused by free radicals. Knowing the molecular basis of how the sirtuin enzymes work may ultimately lead to the rational development of drugs that activate the pathways of enzymes like Sirt3 to slow down the process of aging.
The study is published in Cell.