Mechanisms for the metabolic success of bariatric surgery

Abstract

To date, bariatric surgery remains the most effective strategy for the treatment of obesity and its comorbidities. However, given the enormity of the obesity epidemic, and sometimes variable results, it is not a feasible strategy for the treatment of all obese patients. A simple PubMed search for 'bariatric surgery' reveals over 28 000 papers that have been published since the 1940s when the first bariatric surgeries were performed. However, there is still an incomplete understanding of the mechanisms for the weight loss and metabolic success of surgery. An understanding of the mechanisms is important because it may lead to greater understanding of the pathophysiology of obesity and thus surgery-alternative strategies for the treatment of all obese patients. In this review, the potential mechanisms that underlie the success of surgery are discussed, with a focus on the potential endocrine, neural and other circulatory factors (eg, bile acids) that have been proposed to play a role.

Keywords: bariatric surgery; bile acids; metabolism.

FIGURE 1

The impact of vertical sleeve gastrectomy (VSG) and Roux-en-Y gastric bypass (RYGB) on the central nervous system (CNS), gut and gut-brain axis. The CNS is more highly activated by surgery and induces changes in feeding patterns and macronutrient preference. The gut responds with increases postprandial peptide secretions, increases in plasma bile acids (BA) and changes in the microbiome. The gut-brain axis may integrate these two systems as celiac gangliectomy blunts weight loss responses to RYGB