Efeitos da gastrectomia vertical com e sem omentectomia no metabolismo, inflamação e expressão do sistema renina-angiotensina no tecido adiposo de ratos obesos

Abstract

Obesity is a chronic disease caused by the excess of adipose tissue due to the hyperplasia and/or hypertrophy of the adipocytes. It occurs due to an imbalance between the energy intake and expenditure, where the positive energetic balance, in a cumulative manner, results in disease. The obesity presents a multifactorial etiology, with considerable psychosocial and biological dimensions and has been acquiring alarming proportions. It is considered one of the major public health problems in the modern society. The obesity, especially the visceral, is associated with the increased production of proinflammatory cytokines, resulting in a chronic inflammatory state along with insulin resistance, with a significant increase of diabetes mellitus type II (DM2) and its consequent micro and macrovascular complications. Moreover, the adipose tissue represents an important site for the production of components of the reninangiotensin system (RAS). The hypertrophy of the adipocytes increases the secretion of some of these components, which may cause arterial hypertension and other cardiometabolic alterations with impact on the morbidity and mortality of the population. The bariatric surgery, in addition to effectively treat obesity, also has therapeutic effects on DM2 and dyslipidemia. Among the surgical techniques, the sleeve gastrectomy (SG) initially indicated as the first step of the treatment for patients with high risk or with severe obesity, has been suggested as an only and definitive option due to its satisfactory results concerning the weight loss and improvement of the metabolic profile. Intended to reduce the visceral adipose tissue, the resection of the great omentum has been proposed during the performance of bariatric surgeries. However, there are controversies if the inclusion of the omentectomy as a part of the bariatric surgery would bring an additional metabolic benefit to the obese patients. In this context, this study aimed to evaluate the SG effects in male rats, with obesity induced by diet, in order to expand the knowledge of this technique on the metabolic effects, inflammation and expression of the RAS components in the adipose tissue. This study also evaluated if the omentectomy associated with SG would increment the benefic effects regarding the weight loss, metabolic profile improvement and in the tissue expression of inflammatory markers. The rats were treated during eight weeks with standard diet (STD) or high-fat diet (HFD) and divided into six groups (n=10/group): STD and laparotomy (STD+L), STD and sleeve gastrectomy (STD+SG), STD and sleeve gastrectomy with omentectomy (STD+SGO), HFD and laparotomy (HFD+L), HFD and sleeve gastrectomy (HFD+SG) and HFD and sleeve gastrectomy and omentectomy (HFD+SGO). It was evaluated the body, glycemic and lipid profile and performed analysis of the inflammatory markers (tumor necrosis factoralpha/TNF-α and interleukin-6/IL-6) and RAS components (angiotensin I converting enzyme/ACE, angiotensin I converting enzyme II/ACE2 and angiotensinogen/AGT) expression in the white adipose tissue. The data were analyzed in the Graph Pad Prism 5.0 and 6.0 program, applying the Student’s t-test, Two-Way ANOVA and One-Way ANOVA followed by Bonferroni post-hoc test. The SG led to a significant weight loss, decrease in the adiposity and plasma levels of glucose, C-peptide, insulin and total cholesterol. The performance of SG was associated with a decreased expression of TNF-α, IL-6, AGT and ACE along with an increased expression of ACE2. The animals submitted to SG along with omentectomy also presented weight loss, improvement of the metabolic profile and decrease of the tissue expression of TNF-α, but with no statistically significant differences when compared to the groups of animals submitted to the SG alone. This study showed the benefic effects of the SG on the weight loss, inflammation and in the tissue expression of the RAS components in the white adipose tissue, allowing to be thus considered a therapeutic option to the treatment of obesity, DM2 and its comorbidities. Additionally, in the present study it was not established additional benefic effects of the association between omentectomy and SG in the glycemic and lipid profile and also in the tissue expression of inflammatory markers.