Evaluation of L-Cell Activity in the Small Intestine as Biliopancreatic Loop Extension in Obese Patients With DM2 Submitted to Roux-en-Y Gastric Bypass

This is a prospective, randomized (paired) and morphological study involving 20 adult male and female patients (18-65 years) with severe obesity [body mass index (BMI) > 35 kg/m2] and DM2 undergoing Gastroplasty in Diversion Roux-en-Y in the Bariatric and Metabolic Surgery Unit, Department of Gastroenterology, HC-FMUSP, between February 2020 and December 2022. Patients were randomized (https://hcbredcap.com.br/) into two groups of 10 patients each, according to the extension of the bilio-pancreatic loop, in a proportion of 1:1 by computer model. Patients were evaluated preoperatively (T0) and 6 months (T1) after GDYR.

INTRODUTION: Patients with obesity have a suppressed incretin effect and a consequent imbalance of glycemic homeostasis. Bariatric surgery has the potential of T2DM control in up to 90% of patients with severe obesity due to caloric restriction, improvement of insulin resistance, pancreatic beta cell function, and the incretin effect of glycogen-like protein 1.

In this current scenario, metabolic surgery has taken a considerable role in weight loss, contributing to metabolic control, and showing improvement in the state of obesity and related comorbidities. We already know that conservative treatment has been failing 80% of obese patients, while 80% of obese patients who have undergone metabolic surgery are successful in long-term weight loss and resumption of metabolic functionality, showing better results than drug therapy or only lifestyle change 16 . This adaptive procedure, which is aimed at neuroendocrine improvements instead of gastrointestinal restriction and malabsorption 24 , leads to increased serum levels of the incretins (hormones that stimulate a decrease in blood glucose levels) glucagon- like peptide-1 (GLP-1) and peptide YY (PYY 3-36 ) in postprandial patients five years following surgery. They play key roles in stimulating the secretion of insulin by the endocrine pancreas . It is therefore of considerable importance to understand the secretion mechanisms of epithelial intestinal cells as well as the identity and location of cells responsible for the action of these peptides . In the intestinal epithelium we find cells that release incretins to the response of nutrients in contact with intestinal lumen called L cells . L cell found in the distal ileum and large intestine secretes GLP-1 and peptide YY (PYY) promotes they slow gastric emptying and act as a satiety signal to improve glycemic control.

JUSTIFICATION: number of L cells in activity implies better peptide signaling, response and functioning of the neuroendocrine system.

OBJECTIVE: To analize secretion of L cells in the small intestine for immunohistochemistry and mRNA expression levels before and after (6 months) induced by bariatric surgery .