Gut Microbiota: Modulation of Host Physiology in Obesity

Abstract

Many factors are involved in weight gain and metabolic disturbances associated with obesity. The gut microbiota has been of particular interest in recent years, since both human and animal studies have increased our understanding of the delicate symbiosis between the trillions of microbes that reside in the GI tract and the host. It has been suggested that disruption of this mutual tolerance may play a significant role in modulating host physiology during obesity. Environmental influences such as diet, exercise, and early life exposures can significantly impact the composition of the microbiota, and this dysbiosis can in turn lead to increased host adiposity via a number of different mechanisms. The ability of the microbiota to regulate host fat deposition, metabolism, and immune function makes it an attractive target for achieving sustained weight loss.

FIGURE 1.

Genetic and environmental factors that can lead to eubiosis or dysbiosis of the gut microbiota and that are strongly linked to obesity Bidirectionally, changes in the gut microbiota can alter the metabolism and immune function of the host, thus dramatically affecting the pathogenesis of obesity. TLRs, Toll-like receptors; NLRs, nucleotide-binding oligomerization domain like receptors; LPS, lipopolysaccharide; BA, bile acids; FXR, farnesoid X receptor; TGR5, G-protein-coupled bile acid receptor; GLP-1, glucagon-like peptide-1; PYY, peptide YY; Tregs, regulatory helper T-cells; eCB, endocannabinoid; FMT, fecal microbial transplant; RYGB, Roux-en-Y gastric bypass.