Relief of diabetes by duodenal-jejunal bypass sleeve implantation in the high-fat diet and streptozotocin-induced diabetic rat model is associated with an increase in GLP-1 levels and the number of GLP-1-positive cells

Small intestine-targeted endoscopic bariatrics: Current status and future perspectives

The global obesity epidemic shows no signs of slowing down. Endoscopic bariatric and metabolic therapies (EBMTs) are being increasingly adopted as treatment options for obesity and obesity-related comorbidities, due to their minimally invasive nature and ease of delivery. According to the site of action along the gastrointestinal tract, EBMTs can be divided into two categories: gastric EBMTs, and small intestine-targeted EBMTs. Unlike gastric EBMTs, which work through a volume-restricting mechanism leading to early satiety and reduced caloric intake, small intestine-targeted EBMTs can be metabolically beneficial through foregut and/or hindgut pathways independent of weight loss, and therefore have great potential for the treatment of obesity-related metabolic comorbidities such as type 2 diabetes. Although none of the small intestine-targeted EBMTs have been approved by the US Food and Drug Administration to date, their clinical efficacy and safety have been extensively explored in investigational trials. This review aims to summarize and provide a comprehensive understanding of small intestine-targeted EBMTs in clinical and preclinical settings, and to further discuss their potential mechanisms of action.

Endoscopic Bariatric and Metabolic Therapies for Liver Disease: Mechanisms, Benefits, and Associated Risks

Nonalcoholic fatty liver disease (NAFLD), including advanced-stage nonalcoholic steatohepatitis (NASH), is currently the most common chronic liver disease worldwide and is projected to become the leading indication for liver transplantation (LT). However, there are no effective pharmacological therapies for NAFLD. Endoscopic bariatric and metabolic therapies (EBMTs) are less invasive procedures for the treatment of obesity and its metabolic comorbidities. Several recent studies have demonstrated the beneficial effects of EBMTs on NAFLD/NASH. In this review, we summarize the major EBMTs and their mechanisms of action. We further discuss the current evidence on the efficacy and safety of EBMTs in people with NAFLD/NASH and obese cirrhotic LT candidates. The potential utility of EBMTs in reducing liver volume and perioperative complications in bariatric surgery candidates is also discussed. Moreover, we review the development of liver abscesses as a common serious adverse event in duodenal-jejunal bypass liner implantation.

Effects of Bariatric Endoscopy on Non-Alcoholic Fatty Liver Disease: A Comprehensive Systematic Review and Meta-Analysis

BACKGROUND AND OBJECTIVE

Endoscopic bariatric and metabolic therapies (EBMTs) are emerging minimally invasive therapeutic options for obesity and its related complications, including non-alcoholic fatty liver disease (NAFLD). This study aimed to evaluate the effects of EBMTs on NALFD in patients with obesity.

METHODS

Four databases were searched until Nov 2021. Randomized controlled trials (RCTs) and observational studies reporting liver-related outcomes following Food and Drug Administration (FDA)-approved and non-FDA-approved EBMTs were included. Liver parameters, metabolic parameters, and weight loss were evaluated. Risk of bias was assessed using the "risk of bias" tool in the Cochrane Collaboration for RCTs and the Methodological Index for Non-Randomized Studies criteria for observational studies.

RESULTS

Thirty-three studies with 1710 individuals were included. Regarding the effects of EBMTs on liver fibrosis, a significant decline of NAFLD Fibrosis Score, but not transient elastography-detected liver stiffness or Fibrosis-4 Index, was observed. EBMTs significantly improved liver steatosis (control attenuation parameter and Hepatic Steatosis Index), NAFLD Activity Score, and Homeostasis Model Assessment of Insulin Resistance. EBMTs reduced serum levels of alanine transaminase, aspartate aminotransferase, and gamma-glutamyl transpeptidase considerably. Moreover, EBMTs had reducing effects on the serum levels of triglycerides and total cholesterol as well as body weight.

CONCLUSIONS

Our meta-analysis suggested that EBMTs could ameliorate NAFLD based on the evidence of improved liver steatosis, liver function, and insulin resistance. Large-scale, prospective, long-term studies are warranted to clarify the role of EBMTs in patients with different stages of NAFLD.

Research Progress of Duodenal-Jejunal Bypass Liner in the Treatment of Obesity and Type 2 Diabetes Mellitus

With the development of economy and improvement of people's living standards, the incidence of obesity and type 2 diabetes mellitus (T2DM) has increased significantly and obesity has also become one of the most important risk factors of T2DM. In light of these trends, there have been many ways to take effect in losing weight. However, they also have corresponding deficiencies including inapparent curative effect, complex and incomplete reversible procedures and severe complications. Duodenal-Jejunal Bypass Liner (DJBL), which mimics Roux-en-Y gastric bypass (RYGB), is proved to play a key role in weight loss and control of T2DM. DJBL is reversible, less invasive and is more suitable for the treatment of obesity and T2DM, which is associated with multiple mechanisms, including incretin effect, gastric emptying mechanism, bile acid regulation, intestinal microbiota, inflammatory reaction mechanism and neural mechanism. In our review, we aimed to elaborate DJBL's clinical efficacy, safety and mechanisms in detail.

Myeloid-Derived Growth Factor Promotes Intestinal Glucagon-Like Peptide-1 Production in Male Mice With Type 2 Diabetes

Myeloid-derived growth factor (MYDGF), which is produced by bone marrow-derived cells, mediates cardiac repair following myocardial infarction by inhibiting cardiac myocyte apoptosis to subsequently reduce the infarct size. However, the function of MYDGF in the incretin system of diabetes is still unknown. Here, loss-of-function and gain-of-function experiments in mice revealed that MYDGF maintains glucose homeostasis by inducing glucagon-like peptide-1 (GLP-1) production and secretion and that it improves glucose tolerance and lipid metabolism. Treatment with recombinant MYDGF increased the secretion and production of GLP-1 in STC-1 cells in vitro. Mechanistically, the positive effects of MYDGF are potentially attributable to the activation of protein kinase A/glycogen synthase kinase 3β/β-catenin (PKA/GSK-3β/β-catenin) and mitogen-activated protein kinase (MAPK) kinases/extracellular regulated protein kinase (MEK/ERK) pathways. Based on these findings, MYDGF promotes the secretion and production of GLP-1 in intestinal L-cells and potentially represents a potential therapeutic medication target for type 2 diabetes.

"Dysfunctions" induced by Roux-en-Y gastric bypass surgery are concomitant with metabolic improvement independent of weight loss

Metabolic surgery has been increasingly recommended for obese diabetic patients, but questions remain as to its molecular mechanism that leads to improved metabolic parameters independently of weight loss from a network viewpoint. We evaluated the role of the Roux limb (RL) in Roux-en-Y gastric bypass (RYGB) surgery in nonobese diabetic rat models. Improvements in metabolic parameters were greater in the long-RL RYGB group. Transcriptome profiles reveal that amelioration of diabetes state following RYGB differs remarkably from both normal and diabetic states. According to functional analysis, RYGB surgery significantly affected a major gene group, i.e., the newly changed group, which represented diabetes-irrelevant genes abnormally expressed after RYGB. We hypothesize that novel "dysfunctions" carried by this newly changed gene group induced by RYGB rebalance diabetic states and contribute to amelioration of metabolic parameters. An unusual increase in cholesterol (CHOL) biosynthesis in RL enriched by the newly changed group was concomitant with ameliorated metabolic parameters, as demonstrated by measurements of physiological parameters and biodistribution analysis using [14C]-labeled glucose. Our findings demonstrate RYGB-induced "dysfunctions" in the newly changed group as a compensatory role contributes to amelioration of diabetes. Rather than attempting to normalize "abnormal" molecules, we suggest a new disease treatment strategy of turning "normal" molecules "abnormal" in order to achieve a new "normal" physiological balance. It further implies a novel strategy for drug discovery, i.e. targeting also on "normal" molecules, which are traditionally ignored in pharmaceutical development.

Long-term effects of proximal small bowel exclusion by duodenal-jejunal bypass liner on weight reduction and glycemic control in diabetic patients

BACKGROUND

Exclusion of the proximal gut from nutrient absorption entails significant metabolic benefits. The duodenal-jejunal bypass liner (DJBL) is the first endoscopic device that excludes the first part of the gut by covering it.

OBJECTIVES

To assess weight and glycemic control at the end of treatment and after 1 year of follow-up.

SETTING

Bariatric endoscopy service in a tertiary medical center.

METHODS

Diabetic patients were treated with DJBL and followed prospectively between 2013 and 2016. Data were collected during scheduled visits.

RESULTS

Out of 51 patients treated, 39 completed at least 9 months with the device. Complications were recorded for the entire cohort. Percent of total weight loss was 15.05% ± 6.0% after 12 months of treatment (P < .001 versus baseline). Twelve months postretrieval, percent of total weight loss decreased to 8.75% ± 5.07% (P < .001 versus baseline). Patients with baseline body mass index ≥35 kg/m² experienced greater percent total weight loss changes over time (P < .001). There was a significant effect on hemoglobin A1C levels over time (P = .003), and the nadir was reached at 9 months of treatment (median 6.05% versus 7.20% at baseline, P < .001). Insulin users had consistently higher median hemoglobin A1C values compared with insulin nonusers (P < .001). Adverse events were experienced by 12 of 51 patients (23.5%), of which 4 cases (7.8%) were severe.

CONCLUSIONS

Proximal bowel bypass by DJBL is an effective tool for weight reduction and glycemic control. Metabolic achievements are partially preserved at 1 year after device removal. Because DJBL entails a considerable rate of side effects, strategies to mitigate them are warranted.

A randomised controlled trial of a duodenal-jejunal bypass sleeve device (EndoBarrier) compared with standard medical therapy for the management of obese subjects with type 2 diabetes mellitus

INTRODUCTION

The prevalence of obesity and obesity-related diseases, including type 2 diabetes mellitus (T2DM), is increasing. Exclusion of the foregut, as occurs in Roux-en-Y gastric bypass, has a key role in the metabolic improvements that occur following bariatric surgery, which are independent of weight loss. Endoscopically placed duodenal-jejunal bypass sleeve devices, such as the EndoBarrier (GI Dynamics, Lexington, Massachusetts, USA), have been designed to create an impermeable barrier between chyme exiting the stomach and the mucosa of the duodenum and proximal jejunum. The non-surgical and reversible nature of these devices represents an attractive therapeutic option for patients with obesity and T2DM by potentially improving glycaemic control and reducing their weight.

METHODS AND ANALYSIS

In this multicentre, randomised, controlled, non-blinded trial, male and female patients aged 18-65 years with a body mass index 30-50 kg/m² and inadequately controlled T2DM on oral antihyperglycaemic medications (glycosylated haemoglobin (HbA1c) 58-97 mmol/mol) will be randomised in a 1:1 ratio to receive either the EndoBarrier device (n=80) for 12 months or conventional medical therapy, diet and exercise (n=80). The primary outcome measure will be a reduction in HbA1c by 20% at 12 months. Secondary outcome measures will include percentage weight loss, change in cardiovascular risk factors and medications, quality of life, cost, quality-adjusted life years accrued and adverse events. Three additional subgroups will investigate the mechanisms behind the effect of the EndoBarrier device, looking at changes in gut hormones, metabolites, bile acids, microbiome, food hedonics and preferences, taste, brain reward system responses to food, eating and addictive behaviours, body fat content, insulin sensitivity, and intestinal tissue gene expression.

TRIAL REGISTRATION NUMBER

ISRCTN30845205, ClinicalTrials.gov Identifier NCT02459561.

Distribution and hormonal characterization of primary murine L cells throughout the gastrointestinal tract

Aims/Introduction

Glucagon‐like peptide‐1 (GLP‐1) secreted from enteroendocrine L cells is an incretin that potentiates insulin secretion and is already applied in therapies for type 2 diabetes. However, detailed examination of L cells throughout the gastrointestinal tract remains unclear, because of difficulties in purifying scattered L cells from other cells. In the present study, we identified characteristics of L cells of the upper small intestine (UI), the lower small intestine (LI) and the colon using glucagon‐green fluorescent protein‐expressing mice that express GFP driven by the proglucagon promoter.

Materials and Methods

The localization and density of primary L cells were evaluated by anti‐green fluorescent protein antibody reactivity. GLP‐1 content, messenger ribonucleic acid (mRNA) expression levels and secretion in purified L cells were measured.

Results

The number of L cells significantly increased toward the colon. In contrast, the GLP‐1 content and secretion from L cells were higher in the UI than in the LI and colon. L cells from the UI and LI expressed notably high mRNA levels of the transcription factor, islet 1. The mRNA expression levels of peptide YY in L cells were higher in the LI than in the UI and colon. The mRNA expression levels of gastric inhibitory polypeptide in L cells from the UI were significantly higher compared with those from the LI and colon.

Conclusions

L cells show different numbers and characteristics throughout the gut, and they express different mRNA levels of transcription factors and gastrointestinal hormones. These results contribute to the therapeutic application of promoting GLP‐1 release from L cells for the treatment of type 2 diabetes.