Metabolic endotoxaemia: is it more than just a gut feeling?

PURPOSE OF REVIEW This article reviews the evidence linking gut bacteria, endotoxin, and its circulating levels with inflammatory induced obesity and metabolic disease (metabolic endotoxaemia). RECENT FINDINGS Gut flora analyses have allowed gut microbiota signatures (GMS) to be observed in animal studies of obesity/metabolic disease. In these studies, specific GMS result in a change in obesity and metabolic disease state whereas in humans, analysis remains unclear. Serum studies, examining metabolic endotoxaemia as a biomarker, appear to link long-term cardiovascular disease and type 2 diabetes mellitus (T2DM) through activation of inflammatory pathways. More recent studies note the importance of diet, which shows the dramatic rise in endotoxin following acute or long-term high-fat diet, with the effects exacerbated in T2DM. SUMMARY Gut flora appears to act as an important determinant in the pathogenesis of inflammatory induced obesity/T2DM. Endotoxin may act as the systemic insult, impacted by a high-fat diet, which may regulate this effect, combined with an altered GMS. As such, clinical and dietary intervention to affect this process - on the gut flora, the 'leaky' mucosal membrane and endotoxin coupled lipid absorption or removal of circulating endotoxin - could reduce the progression of inflammatory induced metabolic disease.