title: Mechanisms of Action of Surgical Interventions on Weight-Related Diseases: the Potential Role of Bile Acids.
abstract: Surgical interventions for weight-related diseases (SWRD) may have substantial and sustainable effect on weight reduction, also leading to a higher remission rate of type 2 diabetes (T2D) mellitus than any other medical treatment or lifestyle intervention. The resolution of T2D after Roux-en-Y gastric bypass (RYGB) typically occurs too quickly to be accounted for by weight loss alone, suggesting that these operations have a direct impact on glucose homeostasis. The mechanisms underlying these beneficial effects however remain unclear. Recent research suggests that changes in the concentrations of plasma bile acids might contribute to these metabolic changes after surgery. In this review, we aimed to outline the potential role of bile acids in SWRD. We systematically reviewed MEDLINE, SCOPUS, and Web of Science for articles reporting the effect of SWRD on outcomes published between 1969 and 2016. We found that changes in circulating bile acids after surgery may play a major role through activation of the farnesoid X receptor A (FXRA), the fibroblast growth factor 19 (FGF19), and the G protein-coupled bile acid receptor (TGR5). Bile acid concentration increased significantly after RYGB. Some studies suggest that a transitory decrease occurs at 1 week post-surgery, followed by a gradual increase. Most studies have shown the increase to be proportionate by all bile acid subtypes. Bile acids can regulate glucose metabolism through the expression of TGR5 receptor in L cells, resulting in a release of glucagon-like peptide 1 (GLP-1). It may also induce the synthesis and secretion of FGF19 in ileal cells, thereby improving insulin sensitivity and regulating glucose metabolism. All the present SWRD are involved with changes in food stimulation to the stomach. This implies that discovering and developing the antagonists to TGR5 and FXRA may effectively control metabolic syndrome and the elucidation of the mechanisms underlying the physiological effects related to weight loss and T2D remission after surgery may help to identify new drug targets.
authors.affiliation: State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Chaoyang, Beijing, China.|University of the Chinese Academy of Sciences, Huairou, Beijing, China.
authors.forename: Mohsen
authors.initials: M
authors.lastname: Mazidi
authors.affiliation: The Center for Obesity and Diabetes, Oswaldo Cruz German Hospital, Rua Cincinato Braga, 37 5o. andar, São Paulo, São Paulo, Brazil.
authors.forename: Pedro Paulo P
authors.initials: PP
authors.lastname: de Caravatto
authors.affiliation: State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Chaoyang, Beijing, China.|Institute of Biological and Environmental Science, University of Aberdeen, Aberdeen, Scotland, UK.
authors.forename: John R
authors.initials: JR
authors.lastname: Speakman
authors.affiliation: The Center for Obesity and Diabetes, Oswaldo Cruz German Hospital, Rua Cincinato Braga, 37 5o. andar, São Paulo, São Paulo, Brazil. ricardo.cohen@haoc.com.br.
authors.forename: Ricardo V
authors.initials: RV
authors.lastname: Cohen
mesh_terms: D001647:Bile Acids and Salts / Q000097:blood / Q000502:physiology*; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000209:etiology / Q000601:surgery*; D005346:Fibroblast Growth Factors / Q000097:blood; D015390:Gastric Bypass / Q000379:methods*; D052216:Glucagon-Like Peptide 1 / Q000097:blood; D006801:Humans; D007333:Insulin Resistance / Q000502:physiology; D009767:Obesity, Morbid / Q000097:blood / Q000150:complications / Q000601:surgery*
chemical_list: D001647:Bile Acids and Salts; C117476:FGF19 protein, human; D005346:Fibroblast Growth Factors; D052216:Glucagon-Like Peptide 1
keywords: Bile acids; Mechanisms of action; Metabolic surgery; RYGB; Surgery of weight-related diseases