Low-calorie diet and intestinal microflora
A low–calorie diet – a limited intake of calories while maintaining the fullness of nutrition - has a positive effect on the longevity of many species, including humans. New data obtained by scientists at Sanford Burnham Prebys Medical Discovery Institute, working under the leadership of Dr. Malene Hansen, significantly deepened the understanding of the mechanisms underlying this phenomenon.
In experiments on C.elegans roundworms, they demonstrated that autophagy in intestinal cells is a critical factor for increasing life expectancy. As it turned out, the intestinal cells contained in a low-calorie diet of nematodes are characterized by elevated levels of autophagy, which significantly improves their health.
It is a well-known fact that autophagy plays an important role in increasing life expectancy. This mechanism consists in the destruction of cellular components – protein synthesizing, energy generating and transport systems – to small molecules. This simultaneously removes unnecessary or non-functional cellular components from the cell and provides the building material for the synthesis of new organelles, which is especially important in conditions of limited nutrient intake.
The authors of the study wanted to understand how a low-calorie diet affects autophagy in intestinal cells, the importance of full functioning of which for a long life has long been established. As a model, they used nematodes of the eat-2 line, genetically predisposed to eating less food and having a longer lifespan compared to normal worms. Nematodes of this line are an ideal model for studying the mechanisms underlying the life-extending action of autophagy.
Their experiments have shown that blocking autophagy in the intestinal cells of such worms significantly shortens their life expectancy.
Upon a more detailed study of the effects of inhibition of autophagy on the functioning of the intestine, it was found that, while the intestinal walls of normal worms begin to leak fluid with age, the intestinal walls of individuals of the eat-2 line retain their integrity. Blocking autophagy eliminated this feature, which indicates the importance of intestinal preservation for longevity.
According to Dr. Hansen, today it is still unclear how the integrity of the intestinal wall affects life expectancy. It is possible that the deterioration of the functioning of the intestinal walls associated with normal aging may facilitate the penetration of toxic compounds and pathogens into the body.
The researchers also demonstrated that suppression of autophagy in intestinal cells reduces the activity of low-eating and long-lived worms. A likely explanation is that a decrease in autophagy in one organ may affect other organs, in this case, muscle tissue or motor neurons. Finding out the relationship between motility and autophagy in intestinal cells requires further research, however, the authors suggest that inhibition of autophagy in the intestine may disrupt its ability to absorb nutrients or secretion of hormones important for the functioning of other organs.
Despite the fact that the results of the study indicate the benefits of autophagy for the body, Hansen warns that before regulating the activity of autophagy can be considered as a therapeutic approach, it is necessary to understand in more detail how this process affects both individual cells and the body as a whole.
Article by Sara Gelino et al. Intestinal Autophagy Improves Healthspan and Longevity in C. elegans during Dietary Restriction is published in the journal PLoS Genetics.
Evgeniya Ryabtseva
Portal "Eternal youth" http://vechnayamolodost.ru based on the materials of Sanford-Burnham Prebys Medical Discovery Institute: Dietary restriction increases lifespan through effects on the gut.
15.07.2016