Unrelated to Food: The Cause of Obesity Revealed 0 151

Scientists from the University of Zurich and Zurich University Hospital have discovered that prolonged exposure to polluted air disrupts metabolism, increasing the risk of insulin resistance, obesity, and type 2 diabetes. The study, published in the journal JCI Insight, shows that PM2.5 microparticles — one of the most common types of urban pollution — can interfere with the functioning of brown adipose tissue, which is responsible for burning calories and regulating blood sugar levels.

Experiments on mice exposed to polluted air for 24 weeks showed that brown fat lost its ability to effectively process lipids and produce heat. Researchers recorded disruptions in the expression of genes related to energy metabolism and signs of tissue damage. Further analysis revealed that these changes are based on epigenetic processes — a subtle reprogramming of DNA that does not affect the genetic code itself.

Two enzymes played a key role — HDAC9 and KDM2B, which "reprogram" the activity of genes in brown adipose tissue. When their activity was artificially suppressed, the metabolism of the animals was restored. According to the study leader, Professor Francesco Paneni, these results explain how air pollution can directly affect metabolism and open new targets for the prevention and therapy of metabolic disorders.

The scientists emphasize that the results are particularly relevant for large cities, where levels of PM2.5 particles often exceed World Health Organization standards. Improving air quality, in their opinion, may be as important a factor in combating diabetes and obesity as healthy eating or physical activity.