Adipose tissue is not just a simple reservoir of energy for periods of food scarcity. It contributes significantly to regulation of the metabolism, releasing various molecules into the bloodstream, including microRNAs that modulate the expression of key genes in different parts of the organism, including the liver, pancreas, and muscles.
Research has shown that both aging and obesity can impair the production of these regulatory microRNAs by adipose tissue and favor the development of diseases such as diabetes and dyslipidemia.
The good news is that this degenerative process can be reversed by practicing regular aerobic exercise, according to a study published in Proceedings of the National Academy of Sciences (PNAS).
Experiments with mice and humans have shown that aerobic exercise stimulates expression of an enzyme called DICER, which is essential to the processing of these microRNAs. We, therefore, observed an increase in production of these regulatory molecules by adipose cells, with several benefits for the metabolism." Marcelo Mori, Professor at Institute of Biology, University of Campinas
Mori is one of the principal investigators for the project, which was supported by FAPESP (São Paulo Research Foundation) and conducted in partnership with groups at the University of Copenhagen in Denmark and Harvard University in the United States.
The experiments were performed during the postdoctoral research of Bruna Brasil Brandão, formerly Mori's PhD student and now at Harvard Medical School working as a research fellow in the laboratory of Professor C. Ronald Kahn.
The results showed the occurrence of communication between muscle and adipose tissue during aerobic exercise via signaling molecules secreted into the bloodstream. This exchange of information makes energy consumption by adipose cells more efficient, enabling the metabolism to adapt to exercise and enhancing the performance of the muscles.
The mice were subjected to a 60-minute treadmill running protocol for eight weeks. As they became fitter, treadmill speed and inclination were increased.
At the end, in addition to the improvement in performance, the scientists found a significant elevation in adipocyte levels of DICER expression, which was accompanied by a reduction in body weight and visceral fat.