Translating the biological clock

A low-calorie diet can slow down aging

Anna Kerman, XX2 century, based on the materials of MedicalNewsToday: Low-calorie diet may slow aging by 'rejuvenating biological clock'

A new study has shown that when mice age, the work of the "biological clock" – or circadian rhythms – in stem cells continues. Only priorities change: in the cells of elderly animals, less "attention" is paid to maintaining the condition of the tissue and more to combating stress and restoring damaged DNA. 

Scientists claim that the results of the work may explain why mice age more slowly when they are transferred to a low-calorie diet. Presumably, calorie restriction delays changes in circadian functions that occur in cells during aging. 

The research group, which included scientists from the Institute for Research in Biomedicine (IRB) Barcelona and the University of California, Irvine (University of California, Irvine) reports the results in two articles published in the journal Cell (Circadian Reprogramming in the Liver Identifies Metabolic Pathways of Aging and Aged Stem Cells Reprogram Their Daily Rhythmic Functions to Adapt to Stress). 

The discovery seems to contradict the generally accepted theory that as stem cells age, they lose their circadian rhythm, that is, the cyclic 24-hour activity of certain groups of genes. 

Instead, the old stem cells "maintain a daily rhythm, but now perform another set of functions to solve problems that arise with age," says senior author of the study, Professor Salvador Aznar Benitah, who heads a group studying stem cells and cancer at the IRB. 

"Circadian reprogramming" 

The researchers examined changes in stem cells taken from the skin, muscles and liver of young mice aged 3 months and in older mice aged 18 to 22 months. 

The team found that despite the fact that the genes that controlled the circadian rhythm were equally active in both old and young mice, they influenced various cellular processes. 

For example, in young animals, the circadian rhythm apparatus regulated normal cellular processes associated with the protection and maintenance of tissues. These processes included DNA replication, wound healing, and autophagy, a complex mechanism that eliminates waste and also balances energy sources at critical moments, such as in response to stress. 

However, in older mice, the circadian rhythm apparatus did other things, such as controlling cellular mechanisms to combat stress, including repairing damaged DNA and responding to inflammation. 

The researchers note that while they have not discovered what causes the "circadian reprogramming" that occurs during aging in mice, they found, to their surprise, that it is different and specific to each type of tissue. 

According to the authors of the work, this means that every tissue in the body ages differently, and that this should be taken into account when studying the problem of aging. 

Calorie restriction slows down aging 

The team conducted another experiment in which mice that had been on a low-calorie diet for 6 months were compared with mice that ate normally. 

The researchers found that circadian rhythmic functions in mice from the first group remained virtually unchanged throughout the period, whereas in mice with a normal diet they changed over time, showing signs of "circadian reprogramming". 

Professor Asnar Benita says that "a low-calorie diet contributes significantly to preventing the effects of physiological aging." 

Previous studies on fruit flies have demonstrated that calorie restriction can increase life expectancy. However, this new study is the first to show that it has an effect on the role of circadian rhythm in cell aging. 

Could the effect be the same in humans? 

Professor Asnar Benita explains that maintaining the circadian rhythm of "young" stem cells is important because ultimately these cells serve to renew and preserve very pronounced daily cycles in tissues." 

However, the researchers note that these findings do not say anything about whether calorie restriction will help slow down aging in humans. 

"Such diets [are unlikely] to become widespread, because they entail constant hunger and therefore require great willpower. In addition, such dietary regimes provide the body with a minimum of energy to perform its basic functions, which in the long term can have a negative impact on people's daily lives," explains Professor Asnar Benita 

Portal "Eternal youth" http://vechnayamolodost.ru  29.08.2017