Sirtuins, low–calorie diet and life extension - on the same axis
The results of the work of MIT biology professor Leonard Guarente and his colleagues, published in the December issue of the journal Genes and Development in the article "Neuronal SIRT1 regulates endocrine and behavioral responses to calorie restriction", confirm the relationship between the longevity-associated proteins sirtuins and the life-prolonging effects of a low-calorie diet.
The fact that reducing the caloric content of the diet by 30-40% increases life expectancy and improves the health of animals has been known for decades. In recent years, numerous data have been obtained that the realization of these effects is carried out by sirtuin proteins, which coordinate the work of a number of hormonal systems, regulatory proteins and certain genes, due to which cells remain viable and function normally under stress.
In their latest work, Guarente and his colleagues received another confirmation of this hypothesis. They demonstrated that sirtuins mediate the effect of a low-calorie diet on a brain system known as the somatotropic signaling axis. This system controls the growth of the organism and affects the duration of its life.
The researchers created genetically modified mice in whose brain cells the production of SIRT1 protein, the main representative of the family of sirtuins in mammals, was significantly reduced. These animals, as well as a group of normal mice, were kept on a low-calorie diet. At the same time, in normal animals, there was a decrease in the levels of growth hormones circulating in the bloodstream, which indicated a violation of the functioning of the somatotropic signaling system. No such disorders were observed in the mice of the experimental group.
This observation sheds light on the relationship of the SIRT1 protein with the effects of a low-calorie diet on the somatotropic signaling axis, and confirms the participation of sirtuins in the fundamental mechanisms triggered by calorie restriction of the diet.
Guarente and other experts in the field of aging mechanisms believe that drugs stimulating the production of sirtuins, improving human health in old age and possibly increasing life expectancy, can help in the fight against aging-associated diseases such as diabetes and Alzheimer's disease. The completion of several clinical trials of such drugs with the participation of patients with diabetes mellitus is scheduled for next year.
In the near future, Guarente plans to study the mechanisms by which sirtuins control the work of the somatotropic axis. The results of his work can also help researchers and companies engaged in the search for small molecules that optimally modulate the activity of sirtuins.
Evgeniya Ryabtseva
Portal "Eternal youth" http://vechnayamolodost.ru based on MIT materials: New evidence links sirtuins and life extension.
18.12.2009