Gut Microbiome and Brown Adipose Tissue

The high prevalence of worldwide obesity and its associated metabolic disorders has a very negative impact on health, resulting in increased prevalence of cardiovascular disease, type 2 diabetes, liver steatosis, arteriosclerosis, and some types of cancer. For this reason, the search for new therapeutic solutions to reduce obesity is strongly required. A possible therapeutic approach might be to increase energy expenditure through the enhancement of thermogenic pathways in white (WAT) and brown adipose tissue (BAT). Studies based on mice experiments performed in the first decade of the twenty-first century indicated that gut microbiota can play a relevant role in the modulation of host metabolic homeostasis and energy balance. However, the impact of gut microbiota on energy expenditure through the induction of BAT activity or browning of WAT is still unclear. While some studies point to a possible role of gut microbiota as endogenous modulator of BAT activity or WAT browning, other studies dissociate the impact of the microbiota from this process. Here, we will further review most of these studies in an attempt to understand the reasons for these discrepancies and also go over the few studies in humans exploring the relationship between gut microbiota and WAT browning or BAT activity.