Rejuvenating apples for aging muscles
Aging of a person is accompanied by a decrease in the volume and strength of his muscle tissue. However, the causes of age-related muscle atrophy were still unclear. The first step towards solving the mystery was made by researchers at the University of Iowa, working under the guidance of Professor Christopher Adams. They found that the activation of ATF4 protein, a transcription factor that alters gene expression in skeletal muscle cells, leads to muscle weakening and atrophy in old age, and identified two natural compounds that can reduce the activity of this protein.
In earlier studies, the authors demonstrated that the small molecules ursolic acid and tomatidine contained in apple peel and green tomatoes, respectively, are able to prevent acute muscle atrophy caused by starvation and lack of physical activity. This led them to the idea of testing the ability of these compounds to counteract the most important cause of muscle weakness and atrophy – aging.
(According to Wikipedia, ursolic acid is found not only in apples, but in at least a hundred plants, including cranberries, cranberries and even camel thorn. Its antimicrobial, hepatoprotective, anti-inflammatory, anti-allergic, antiviral, cytotoxic, and antitumor properties are known. Tomatidine is also found in a relative of tomatoes – potatoes, and has anti-inflammatory properties.)
To do this, they kept old mice with age-related muscle weakness for two months on a diet containing 0.27% ursolic acid or 0.05% tomatidine. Subsequent examination of the animals showed that both compounds provided an increase in muscle mass by 10% and, more importantly, increased the quality of muscle tissue (strength per unit mass) by 30%.
Further study of the molecular effects of ursolic acid and tomatidine in aging muscle tissue showed that both compounds inhibit the activity of a group of genes activated by the transcription factor ATF4. Experiments on genetically modified mice that do not have the ATF4 gene in skeletal muscle cells have demonstrated that the muscles of such animals are resistant to the destructive effects of aging.
The authors hope that their results will help to understand in detail the molecular mechanisms of age-related muscle atrophy and will form the basis of new methods to combat this adverse manifestation of aging from time to time.
Article by Christopher M. Adams et al. Identification and small molecule inhibition of an ATF4-dependent pathway to age-related skeletal muscle weakness and atrophy is published in the Journal of Biological Chemistry.
Evgeniya Ryabtseva
Portal "Eternal youth" http://vechnayamolodost.ru based on the materials of the University of Iowa: Keeping older muscles strong.
14.09.2015