Effects of various gastrointestinal procedures on β-cell function in obesity and type 2 diabetes

Apolipoprotein A-IV and its derived peptide, T55-121, improve glycemic control and increase energy expenditure

It is crucial to understand the glucose control within our bodies. Bariatric/metabolic surgeries, including laparoscopic sleeve gastrectomy (LSG) and Roux-en-Y gastric bypass (RYGB), provide an avenue for exploring the potential key factors involved in maintaining glucose homeostasis since these surgeries have shown promising results in improving glycemic control among patients with severe type 2 diabetes (T2D). For the first time, a markedly altered population of serum proteins in patients after LSG was discovered and analyzed through proteomics. Apolipoprotein A-IV (apoA-IV) was revealed to be increased dramatically in diabetic obese patients following LSG, and a similar effect was observed in patients after RYGB surgery. Moreover, recombinant apoA-IV protein treatment was proven to enhance insulin secretion in isolated human islets. These results showed that apoA-IV may play a crucial role in glycemic control in humans, potentially through enhancing insulin secretion in human islets. ApoA-IV was further shown to enhance energy expenditure and improve glucose tolerance in diabetic rodents, through stimulating glucose-dependent insulin secretion in pancreatic β cells, partially via Gαs-coupled GPCR/cAMP (G protein-coupled receptor/cyclic adenosine monophosphate) signaling. Furthermore, T55-121, truncated peptide 55-121 of apoA-IV, was discovered to mediate the function of apoA-IV. These collective findings contribute to our understanding of the relationship between apoA-IV and glycemic control, highlighting its potential as a biomarker or therapeutic target in managing and improving glucose regulation.

Metabolomic signatures after bariatric surgery - a systematic review

Metabolomics emerged as an important tool to gain insights on how the body responds to therapeutic interventions. Bariatric surgery is the most effective treatment for severe obesity and obesity-related co-morbidities. Our aim was to conduct a systematic review of the available data on metabolomics profiles that characterize patients submitted to different bariatric surgery procedures, which could be useful to predict clinical outcomes including weight loss and type 2 diabetes remission. For that, the Preferred Reporting Items for Systematic Reviews and Meta-Analyses - PRISMA guidelines were followed. Data from forty-seven original study reports addressing metabolomics profiles induced by bariatric surgery that met eligibility criteria were compiled and summarized. Amino acids, lipids, energy-related and gut microbiota-related were the metabolite classes most influenced by bariatric surgery. Among these, higher pre-operative levels of specific lipids including phospholipids, long-chain fatty acids and bile acids were associated with post-operative T2D remission. As conclusion, metabolite profiling could become a useful tool to predict long term response to different bariatric surgery procedures, allowing more personalized interventions and improved healthcare resources allocation.

Non-alcoholic fatty pancreas disease - practices for clinicians

Obesity is a growing health burden worldwide, increasing the risk for several diseases featuring the metabolic syndrome - type 2 diabetes mellitus, dyslipidemia, non-alcoholic fatty liver disease and cardiovascular diseases. With the increasing epidemic of obesity, a new pathologic condition has emerged as a component of the metabolic syndrome - that of non-alcoholic fatty pancreas disease (NAFPD). Similar to non-alcoholic fatty liver disease (NAFLD), NAFPD comprises a wide spectrum of disease - from deposition of fat in the pancreas - fatty pancreas, to pancreatic inflammation and possibly pancreatic fibrosis. In contrast with NAFLD, diagnostic evaluation of NAFPD is less standardized, consisting mostly in imaging methods. Also the natural evolution of NAFPD and its association with pancreatic cancer is much less studied. Not least, the clinical consequences of NAFPD remain largely presumptions and knowledge about its metabolic impact is limited. This review will cover epidemiology, pathogenesis, diagnostic evaluation tools and treatment options for NAFPD, with focus on practices for clinicians.

IMPACT OF WEIGHT LOSS TRAJECTORY FOLLOWING RANDOMIZATION TO BARIATRIC SURGERY ON LONG-TERM DIABETES GLYCEMIC AND CARDIOMETABOLIC PARAMETERS

Objective: It is unclear whether acute weight loss or the chronic trajectory of weight loss after bariatric surgery is associated with long-term type 2 diabetes mellitus (T2DM) glycemic improvement. This ancillary study of the Surgical Treatment and Medications Potentially Eradicate Diabetes Efficiently (STAMPEDE) trial aimed to answer this question. Methods: In STAMPEDE, 150 patients with T2DM were randomized to bariatric surgery, and 96 had 5-year follow-up. Data post-Roux-en-Y gastric bypass (RYGB, n = 49) and sleeve gastrectomy (SG, n = 47) were analyzed. We defined percent weight loss in the first year as negative percent decrease from baseline weight to lowest weight in the first year. Percent weight regain was positive percent change from lowest weight in the first year to fifth year. Weight change was then correlated with cardiometabolic (CM) and glycemic outcomes at 5 years using Spearman rank correlations and multivariate analysis. Results: In both RYGB and SG, less weight loss in the first year positively correlated with higher 5-year glycated hemoglobin (HbA1c) (RYGB, β = +0.13; P<.001 and SG, β = 0.14; P<.001). In SG, greater weight regain from nadir positively correlated with higher HbA1c (β = 0.06; P = .02), but not in RYGB. Reduced first-year weight loss was also correlated with increased 5-year triglycerides (β = 1.81; P = .01), but not systolic blood pressure. Weight regain did not correlate with CM outcomes. Conclusion: Acute weight loss may be more important for T2DM glycemic control following both RYGB and SG as compared with weight regain. Clinicians should aim to assist patients with achieving maximal weight loss in the first year post-op to maximize long-term health of patients. Abbreviations: BMI = body mass index; HbA1c = glycated hemoglobin; RYGB = Roux-en-Y gastric bypass; SBP = systolic blood pressure; SG = sleeve gastrectomy; STAMPEDE = Surgical Treatment and Medications Potentially Eradicate Diabetes Efficiently; T2DM = type 2 diabetes mellitus; TG = triglyceride.

Obesity in Type 1 Diabetes: Pathophysiology, Clinical Impact, and Mechanisms

There has been an alarming increase in the prevalence of obesity in people with type 1 diabetes in recent years. Although obesity has long been recognized as a major risk factor for the development of type 2 diabetes and a catalyst for complications, much less is known about the role of obesity in the initiation and pathogenesis of type 1 diabetes. Emerging evidence suggests that obesity contributes to insulin resistance, dyslipidemia, and cardiometabolic complications in type 1 diabetes. Unique therapeutic strategies may be required to address these comorbidities within the context of intensive insulin therapy, which promotes weight gain. There is an urgent need for clinical guidelines for the prevention and management of obesity in type 1 diabetes. The development of these recommendations will require a transdisciplinary research strategy addressing metabolism, molecular mechanisms, lifestyle, neuropsychology, and novel therapeutics. In this review, the prevalence, clinical impact, energy balance physiology, and potential mechanisms of obesity in type 1 diabetes are described, with a special focus on the substantial gaps in knowledge in this field. Our goal is to provide a framework for the evidence base needed to develop type 1 diabetes-specific weight management recommendations that account for the competing outcomes of glycemic control and weight management.

The Gut Microbiome as a Target for the Treatment of Type 2 Diabetes

PURPOSE OF REVIEW

The objective of this review is to critically assess the contributing role of the gut microbiota in human obesity and type 2 diabetes (T2D).

RECENT FINDINGS

Experiments in animal and human studies have produced growing evidence for the causality of the gut microbiome in developing obesity and T2D. The introduction of high-throughput sequencing technologies has provided novel insight into the interpersonal differences in microbiome composition and function. The intestinal microbiota is known to be associated with metabolic syndrome and related comorbidities. Associated diseases including obesity, T2D, and fatty liver disease (NAFLD/NASH) all seem to be linked to altered microbial composition; however, causality has not been proven yet. Elucidating the potential causal and personalized role of the human gut microbiota in obesity and T2D is highly prioritized.

Deactivation of the NLRP3 inflammasome in infiltrating macrophages by duodenal-jejunal bypass surgery mediates improvement of beta cell function in type 2 diabetes

OBJECTIVE

Bariatric surgery could improve pancreatic beta cell function, thereby leading to the remission of the type 2 diabetes mellitus (T2DM). However, the specific mechanism underlying this phenomenon is yet to be revealed. The aim of this study is to test the hypothesis that Nod-like receptor family pyrin domain containing 3 (NLRP3) inflammasome in infiltrating macrophages plays an important role in the modulation of beta cell function after duodenal-jejunal bypass (DJB) surgery.

METHODS

DJB and sham surgery were performed in diabetic Sprague-Dawley (SD) rats induced by high-fat diet (HFD) and streptozotocin (STZ). Body weight, food intake, and glucose tolerance test (GTT) were measured at indicated time points. Apoptosis of the beta cells was measured by Terminal deoxynucleotidyl transferase mediated dUTP Nick End Labeling (TUNEL) assay. We also assessed the macrophage content and NLRP3 expression in the rat model. Furthermore, macrophage reconstitution was performed after DJB surgery. Beta cell function and NLRP3 inflammasome pathway were re-evaluated in wild-type macrophage reconstitution group and NLRP3-knockdown macrophage reconstitution group.

RESULTS

DJB surgery group rats displayed rapid and sustained improvement in glucose tolerance. Decreased apoptosis and improved secretion function of the beta cells were observed in DJB surgery group. NLRP3 inflammasome pathway in infiltrating macrophages was also suppressed after DJB surgery. Moreover, diabetic remission acquired by DJB sustained in NLRP3-knockdown macrophage reconstitution group, while extinguished in group reconstituted with wild-type macrophage.

CONCLUSIONS

NLRP3 inflammasome deactivation in infiltrating macrophages is involved in marked beta cell function improvement after DJB surgery.

Effect of Gastrogastric Fistula Closure in Type 2 Diabetes

INTRODUCTION

Roux-en-Y gastric bypass (RYGB) has been shown to significantly improve glucose control in patients with type 2 diabetes (T2DM). The formation of a gastrogastric fistula (GGF) allows nutrients to pass through the native route, rather than bypassing the duodenum in typical RYGB configuration. We sought to evaluate the effect of revisional bariatric surgery for known GGF on control of diabetes.

METHODS

A retrospective chart review of a single academic institution was performed to identify patients who had T2DM at the time of corrective surgery for a GGF. Baseline characteristics, and postoperative outcomes including changes in body mass index (BMI), glycated hemoglobin, fasting blood glucose (FBG), and diabetes medications were assessed.

RESULTS

Ten patients were identified with GGF who had T2DM at the time of corrective surgery. Patients had a male-to-female ratio of 2:3, a mean age of 59.2 ± 10 years, a mean baseline BMI of 38.1 ± 17.6 kg/m², and a median duration of 9 years (interquartile range 6-14) from initial RYGB to revision. At a mean follow-up of 14.9 ± 8.5 months, a mean reduction in BMI of 4.9 ± 6 kg/m² was associated with a significant mean reduction in FBG (167.1 ± 88.2 vs. 106.1 ± 20.4 mg/dL, p = 0.04) and number of diabetes medications (1.4 ± 0.8 vs. 0.7 ± 0.7, p = 0.04).

CONCLUSION

In patients with diabetes and GGF, a corrective surgery for closure of fistula and restoration of bypass anatomy results in improvement of glucose control and status of diabetes medications. This finding can highlight the potential metabolic significance of duodenal exclusion.