As the body ages, brown adipose tissue activity decreases, fewer calories are burned, and this can contribute to obesity and certain chronic cardiovascular diseases that worsen with age. A study led by the University of Barcelona has identified a key molecular mechanism in the loss of brown fat activity during ageing. The study opens up new perspectives for designing strategies to boost the activity of this tissue and prevent chronic metabolic and cardiovascular diseases as the population ages.
The paper, published in the journal Science Advances , is led by Professor Joan Villarroya, from the Faculty of Biology and the Institute of Biomedicine of the UB (IBUB) - based at the Barcelona Science Park-UB - and the CIBER Area for Physiopathology of Obesity and Nutrition (CIBEROBN). Teams from the Albert Einstein College of Medicine in New York (United States) are also collaborating.
Brown adipose tissue: how to prevent its inactivation during ageing?
Brown adipose tissue is the main organ capable of producing body heat from fat (thermogenesis). It has a protective function against obesity, type 2 diabetes and cardiovascular disease, and is activated in response to certain factors - such as cold or dietary stimuli -, in which the body reacts by increasing the metabolism of excess calories consumed. However, the molecular mechanisms that cause its activity to decrease during ageing are still unknown.
The study, carried out in animal models, reveals that the thermogenic activation of brown fat is associated with an increase in a cellular process known as chaperone-mediated autophagy (CMA), which enhances the selective degradation of specific proteins.
During ageing, chaperone-mediated autophagy decreases, causing a loss of brown adipose tissue activity. "Therefore, acting on chaperone-mediated autophagy may play a key role in modulating the tissue activity", says Professor Joan Villarroya, from the Department of Biochemistry and Molecular Biomedicine at the UB's Faculty of Biology.
The activity of brown adipose tissue is tightly regulated to prevent uncontrolled metabolization of different chemical substrates. This control is ensured by proteins that act as repressors of thermogenic activity and are activated whenever the body does not need to activate brown adipose tissue.
