Preserved Insulin Secretory Capacity and Weight Loss Are the Predominant Predictors of Glycemic Control in Patients With Type 2 Diabetes Randomized to Roux-en-Y Gastric Bypass

Metabolic/Bariatric Surgery is Safe and Effective in People with Obesity, Type 2 Diabetes Mellitus and Chronic Kidney Disease: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Obesity, type 2 diabetes (T2D), and chronic kidney disease (CKD) are thought to increase surgical risks and reduce weight loss after metabolic/bariatric surgery (MBS). Electronic databases were searched between January 2013 and August 2023 for randomized controlled trials (RCT) of MBS reporting data on the safety, total weight loss (TWL), and metabolic control in patients with and without CKD. Forty-four out of 2904 articles were analyzed, representing 1470 patients. No significant differences were found in TWL after 1 year (- 19%, CI - 0.19 to - 0.18 vs.: - 15%, CI - 0.20 to - 0.09, p = 0.13) or after 5 years (- 20%, CI - 0.21 to - 0.18 vs. Group - 16%, CI - 0.28 to - 0.04, p = 0.50).Similarly, there were no significant differences in HbA1c at 1 year (- 1.06, CI - 1.37 to - 0.76 vs. Group 2: - 1.52, CI - 2.25 to - 0.79, p = 0.26) or after 5 years (- 0.97, CI - 1.53 to 0.41 vs. Group 2: - 1.09, CI - 2.21 to 0.03, p = 0.85). For fasting plasma glucose, no differences were seen at 2 years (- 30.43, CI - 60.47 to 0.39 vs. - 35.11, CI - 48.76 to - 21.46, p = 0.78) or after 5 years (- 11.24, CI - 53.38 to 30.89 vs. - 5.4, CI 20.22 to 9.42, p = 0.80). In terms of total cholesterol, no significant differences were found after 1 year (- 10.36, CI - 32.94 to 12.22 vs. - 19.80, CI - 39.46 to - 0.14, p = 0.54) or after 5 years (- 7.43, CI - 25.09 to 5.23 vs. - 21.30, CI - 43.08 to 0.49, p = 0.15). For triglycerides, both showed similar reductions after 1 year (- 76.21, CI - 112.84 to - 39.59 vs. - 78.00, CI - 100.47 to - 55.53, p = 0.94) and after 5 years (- 79.65, CI - 121.09 to - 38.21 vs. - 53.15, CI - 71.14 to - 35.16, p = 0.25). The presence of CKD in patients with obesity and T2D does not reduce the safety and efficacy of MBS.

Bile acids, fibroblast growth factor-19, and glucagon-like peptide-1 levels in the long term after bariatric surgery

OBJECTIVES

Glucagon-like peptide-1(GLP-1) is a hormone often measured in the short-term following Roux-en-Y gastric bypass (RYGB) due to its elevation and association with improvement of glucose metabolism. We examined the durability of this effect in patients with type 2 diabetes mellitus (DM) in the long term after RYGB.

METHODS

Obese patients with type 2 DM who had received RYGB 10 years ago (n = 10) were enrolled and a meal tolerance test (MTT) was performed. A matched control group with type 2 DM (n = 5) underwent MTT.

RESULTS

Glucose levels during the MTT did not differ between patients with RYGB and the nonsurgical group. Insulin, C-peptide and GLP-1 levels during MTT were significantly higher in patients with RYGB compared with the nonsurgical group (Area under the curve [AUC] of insulin; 57.4 ± 22.9 vs. 27.7 ± 11.1 mIU/L•hr, P = 0.008; AUC of total GLP-1; 189.4 ± 74.72 vs. 52.13 ± 10.23 pM •hr, P = 0.002), and in particular, peak insulin, C-peptide and GLP-1 levels observed 30-45 min after eating were markedly different from those in the nonsurgical group. Bile acids (BAs) and fibroblast growth factor 19 (FGF-19) levels during MTT were higher in patients with RYGB compared with the nonsurgical group. Peak BAs and FGF-19 levels tended to be higher in the RYGB.

CONCLUSIONS

An enhanced GLP-1 response was noted 10 years after RYGB, strongly suggesting a durability of this effect. BAs and FGF-19 were increased in the RYGB group, but not as much as the pronounced increase in GLP-1 secretion.

Comparative effectiveness of metabolic and bariatric surgeries: a network meta-analysis

Bariatric surgery is recommended for patients with unhealthy weight. Our study aim to compare and rank different bariatric surgical approaches in reducing weight parameters. We searched MEDLINE, Cochrane CENTRAL, Scopus, and Web of Science databases from inception to September 2023. We extracted all outcomes as mean change from the baseline. The mean difference and 95% confidence interval were used as a summary measure. All analysis was conducted with R version 4.2.2 (2022-10-31) and R Studio version 2022.07.2 (2009-2022) (RStudio, Inc.). Included surgeries were: Biliopancreatic diversion (BPD-RYGB), Roux-en-Y Gastric Bypass (RYGB), Laparoscopic Gastric Plication (LGP), Duodenal-Jejunal Bypass Sleeve (DJBS), Single-anastomosis gastric bypass (SAGB), Laparoscopic vertical banded gastroplasty (LVBG), Sleeve Gastrectomy (SG), Laparoscopic adjustable gastric banding (LAGB), Gastric plication, Biliopancreatic diversion (BPD), and Intra-gastric balloon (IGB). Only clinical trials were included, with outcomes focused on weight parameters such as reductions in BMI (kg/m²), weight (kg), waist circumference (cm), fat mass (kg), and excess weight loss (EWL) (%). Our analysis of 67 studies showed that SADI-S was the best surgical technique in decreasing BMI (kg/m2) (MD = -18.06; 95% CI [-25.31; -10.81]) and DS follows in efficacy with a P-score (MD = -18.88; 95% CI [-31.15; -6.62]) however the pooled analysis was heterogeneous (I2 = 98.5%). For weight (kg), waist circumference (cm), and fat mass (kg), BPD-RYGB was the best surgical technique to reduce these parameters (MD = -41.48; 95% CI [-47.80, -35.51], MD = -29.08; 95% CI [-37.16, -21.00], and MD = -31.11; 95% CI [-38.77, -23.46]; respectively). The pooled analysis was heterogeneous except in fat mass (I2 = 0%, p-value = 0.8). Our network meta-analysis showed that the best surgical technique in increasing EWL (%) was RY-DS (MD = -61.27; % CI [-91.72; -30.82]) the next one in efficacy according to P-score was LVBG (MD = -59.03; % CI [-84.47; -33.59]). SADI-S is most effective in reducing BMI followed by RYGB. DS was associated with most estimated weight loss %.

β-Cell Function and Insulin Dynamics in Obese Patients With and Without Diabetes After Sleeve Gastrectomy

Improved β-cell function seems to be essential for better glucose homeostasis after Roux-en-Y gastric bypass but is less studied after sleeve gastrectomy (SG). We evaluated the effects of SG on β-cell function in obese patients with diabetes (DM group) and without (control group) in response to both oral and intravenous glucose stimulation. The DM group demonstrated impaired insulin sensitivity and insulin response to glucose before surgery. The insulin sensitivity index of both groups significantly improved after SG. In addition, the insulin response to glucose (early insulinogenic index in oral glucose tolerance test and acute insulin response to glucose in an intravenous glucose tolerance test) increased in the DM group but decreased in the control group. As a result, β-cell function improved significantly in both groups after SG since the disposition index (DI) increased in both. However, the DI of the DM group was not restored to the level of control group up to 1 year after SG. Our results support that obese patients, with and without diabetes, could benefit from SG in β-cell function. For obese patients at risk for or who have been diagnosed with diabetes, interventions should be recommended early to preserve or restore β-cell function, and SG could be an effective choice. Further studies are needed for long-term effects.

ARTICLE HIGHLIGHTS

Insulin resistance levels predicted metabolic improvement and weight loss after metabolic surgery in Chinese patients with type 2 diabetes

BACKGROUND

The causes for failure of metabolic improvement and inadequate weight loss after metabolic surgery (MS) in Chinese patients with type 2 diabetes (T2D) have not been fully elucidated. The effect of insulin resistance (IR) on the outcome of T2D, hypertension, hyperlipidemia, and obesity after MS in Chinese patients with T2D and a body mass index (BMI) of 25-32.5 kg/m2 warrants further study.

OBJECTIVES

Patients with T2D and a BMI of 25-32.5 kg/m2 who underwent MS between July 2019 and June 2021 were included.

SETTING

University hospital, China.

METHODS

IR levels were evaluated with the glucose disposal rate (GDR). Improvement of T2D, hypertension, and hyperlipidemia was assessed with the composite triple endpoint (CTEP), and weight loss was assessed with the percent of total weight loss (%TWL). Partial correlation analysis, binary logistic regression analysis, multiple linear regression analysis, receiver operating characteristic curve (ROC) analysis, and subgroup analysis were used to analyze the relationship between the CTEP, %TWL at 1 year postoperative, and GDR preoperative.

RESULTS

This study analyzed the data of 51 patients with T2D and a BMI of 25-32.5 kg/m2 (30 men and 21 women) with a mean preoperative GDR of 3.72 ± 1.48 mg/kg/min. Partial correlation coefficients between CTEP, %TWL, and GDR were .303 (P = .041) and .449 (P = .001), respectively. The preoperative GDR was significantly positively correlated with CTEP (OR = 1.610, P = .024) and %TWL (β = 1.38, P = .003). The preoperative GDR predicted cutoff values of 4.36 and 5.35 mg/kg/min for CTEP attainment and %TWL ≥ 20%, respectively.

CONCLUSION

IR levels predicted metabolic improvement and weight loss 1 year after MS in Chinese patients with T2D and a BMI of 25-32.5 kg/m2.

The oral disposition index calculated from a meal tolerance test is a crucial indicator for evaluating differential normalization of postprandial glucose and triglyceride excursions in morbidly obese patients after laparoscopic sleeve gastrectomy

To determine the normalization of postprandial blood glucose (PG) and triglyceride (TG) excursions in 30 morbidly obese patients with or without diabetes mellitus (DM) 1-year after they underwent a laparoscopic sleeve gastrectomy (LSG) vs. their pre-surgery data, we administered the 75-g oral glucose tolerance test (OGTT) and a meal tolerance test (MTT) using a 75-g glucose-equivalent carbohydrate- and fat-containing meal. The results were as follows; (i) Postoperative body-weight reduction was associated with DM remission and reduced multiple cardiometabolic risks. (ii) OGTT data showing postprandial hyper-insulinemic hypoglycemia in many post-surgery patients were associated with overdiagnosis of improved glucose tolerance. However, postoperative MTT data without hypoglycemia showed no improvement in the glucose tolerance vs. pre-surgery data. (iii) The disposition index (DI) i.e., [Matsuda index] × (Glucose-induced insulin secretion) was progressively worsened from normal glucose tolerance to DM patients after LSG. These post-surgery DI values measured by the MTT were correlated with 2h-plasma glucose levels and were not normalized in DM patients. (iv) The baseline, 2h-TG, and an increase in 2h-TG values above baseline were correlated with the insulin resistance index, DI, or HbA1c; These TG values were normalized post-LSG. In conclusion, the glucose tolerance curve measured by the MTT was not normalized in T2DM patients, which was associated with impaired normalization of the DI values in those patients 1-year after the LSG. However, the baseline TG and a fat-induced 2h-TG values were normalized postoperatively. The MTT can be used to assess normalization in postprandial glucose and TG excursions after LSG.

The Impact of Bariatric Surgery on Weight Loss and Glycemic Control in Patients With Obesity and Type 2 Diabetes: A Systematic Review

Obesity and type 2 diabetes mellitus (T2DM) are global health challenges. Bariatric surgery has emerged as a potential intervention for managing these conditions, but its efficacy and impact need comprehensive evaluation. This systematic review aimed to assess the impact of bariatric surgery on weight loss and glycemic control in patients with obesity and T2DM. Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, a systematic search was conducted in October 2023, primarily using PubMed. Studies were selected based on specific inclusion and exclusion criteria, focusing on bariatric surgery's relationship with weight loss and glycemic control. The quality of the included studies was assessed using the ROBINS-I (risk of bias in non-randomized studies of interventions) risk of bias assessment approach. Out of 272 initially identified studies, nine met the inclusion criteria. These studies, encompassing 10,445 participants from various global locations, predominantly targeted middle-aged participants. The findings consistently highlighted the benefits of bariatric surgery in weight reduction and improved glycemic control. However, the degree of benefits varied based on the type of surgical procedure, patient's BMI, and other individual factors. Bariatric surgery offers significant advantages in managing obesity and T2DM. While it consistently aids in weight reduction and glycemic control, individualized treatment approaches considering various patient and procedural factors are crucial for optimal outcomes. When applied to the right patient, bariatric surgery can offer significantly better glycemic control and weight reduction when compared to only medication control and lifestyle adjustments. However, future research should focus on long-term outcomes and the integration of surgical interventions with lifestyle and medical management.

Guf1 overexpression improves pancreatic β cell functions in type 2 diabetes mellitus rats with Roux-en-Y gastric bypass (RYGB) surgery

The Roux-en-Y gastric bypass (RYGB) is a one-of-a-kind treatment among contemporary bariatric surgical procedures, and its therapeutic effects for type 2 diabetes mellitus (T2DM) are satisfactory. The present study performed isobaric tags for relative and absolute quantification (iTRAQ) combined with liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis identifying different proteomics between T2DM rats with or without Roux-en-Y gastric bypass (RYGB) surgery, and GTP binding elongation factor GUF1 (Guf1) was first found to be significantly upregulated in rats from the T2DM plus RYGB group. In the cellular lipotoxicity model induced by palmitic acid stimulation of rat pancreatic beta cell line, INS-1, palmitic acid treatment inhibited cell viability, suppressed GSIS, promoted lipid droplet formation, promoted cell apoptosis, and induced mitochondrial membrane potential loss. The effects of palmitic acid on INS-1 cells mentioned above could be partially eliminated by Guf1 overexpression but aggravated by Guf1 knockdown. Last, under palmitic acid treatment, Guf1 overexpression promotes the PI3K/Akt and NF-κB signaling but inhibits the AMPK activation. Guf1 is upregulated in T2DM rats who received RYGB, and Guf1 overexpression improves cell mitochondrial functions, increases cell proliferation, inhibits cell apoptosis, and promotes cell functions in palmitic acid-treated β cells.

Predictors of Type 2 Diabetes Mellitus Remission After Metabolic Surgery in Asian Patients with a BMI < 32.5 kg/m2

BACKGROUND

Metabolic surgery is an effective treatment for type 2 diabetes mellitus (T2DM) in patients with obesity. However, the efficacy in patients with body mass index (BMI) < 32.5 kg/m², especially in Asian populations, has not been widely reported, and there are few studies on the prediction of diabetes remission.

METHODS

We evaluated 112 patients with T2DM who underwent metabolic surgery between October 2008 and November 2019. The basic data of the patients were collected, and clinical variables were measured at 6 months, 1 year, and 2 years after metabolic surgery. Four independent predictors of surgical outcomes were identified to construct the prediction score.

RESULTS

Diabetes remission occurred for 38 of the 112 patients. Ninety patients underwent Roux-en-Y gastric bypass, while the remaining 22 patients underwent sleeve gastrectomy. Weight, glucose, and lipid metabolism parameters were improved significantly after metabolic surgery. Age, BMI, insulin use, and duration were independent predictors of T2DM remission. The above four factors were defined with scores and developed ABID (age, BMI, insulin use, duration) scoring system. Patients with greater ABID scores had a greater probability of diabetes remission (from 0% at score 0 to 100% at score 4).

CONCLUSIONS

The ABID score is a simple and easy-to-implement prediction score system of diabetes remission after metabolic surgery for T2DM patients with a BMI < 32.5 kg/m².

The effects of bariatric surgery on dyslipidemia and insulin resistance in overweight patients with or without type 2 diabetes: a systematic review and network meta-analysis

Obesity has become an epidemic in several regions globally; it may lead to cardiovascular diseases, diabetes, and dyslipidemia. Despite many therapies, all bariatric procedures fail in some patients. There is a lack of literature comparing treatment effects on specific metabolic indexes. PubMed, Embase, and Cochrane Central Register of Controlled Trials were searched for relevant articles. GeMTC and R software were used to perform a network meta-analysis, draw forest plots, investigate the possibility of statistical heterogeneity, generate I² statistics, rank probabilities, and evaluate relative effects of surgical procedures. All analyses were based on a Bayesian consistency model. We included 35 randomized controlled trials, comprising 2198 individuals and 13 interventions. For patients with high insulin resistance, single-anastomosis (mini-) gastric bypass (SAGB) and sleeve gastrectomy (SG) may be effective options, with mean differences (95% confidence intervals [CIs]) of -4.45 (-9.04 to -.34) and -4.23 (-6.74 to -2.22), respectively, compared with control groups. For patients with severe dyslipidemia, in addition to SAGB and SG, duodenal switch (DS) may be an effective surgery, with mean differences (95% CIs) of -.97 (-1.39 to -.55), -1.98 (-3.76 to -.19), .53 (.04 to 1.04), and -.94 (-1.66 to -.16) compared with control groups in terms of triglycerides, total cholesterol, high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C) concentrations, respectively. In adult overweight patients with or without diabetes, SAGB and SG are most effective at ameliorating insulin resistance. SAGB, Roux-en-Y gastric bypass + omentectomy, and DS are useful for reducing triglycerides, total cholesterol, and LDL-C. SG + omentectomy elevates HDL-C concentrations best. Adjustable gastric band and biliopancreatic diversion may not control insulin resistance or dyslipidemia well.

Imaging Beta-Cell Function in the Pancreas of Non-Human Primates Using a Zinc-Sensitive MRI Contrast Agent

Non-invasive beta cell function measurements may provide valuable information for improving diabetes diagnostics and disease management as the integrity and function of pancreatic beta cells have been found to be compromised in Type-1 and Type-2 diabetes. Currently, available diabetes assays either lack functional information or spatial identification of beta cells. In this work, we introduce a method to assess the function of beta cells in the non-human primate pancreas non-invasively with MRI using a Gd-based zinc(II) sensor as a contrast agent, Gd-CP027. Additionally, we highlight the role of zinc(II) ions in the paracrine signaling of the endocrine pancreas via serological measurements of insulin and c-peptide. Non-human primates underwent MRI exams with simultaneous blood sampling during a Graded Glucose Infusion (GGI) with Gd-CP027 or with a non-zinc(II) sensitive contrast agent, gadofosveset. Contrast enhancement of the pancreas resulting from co-release of zinc(II) ion with insulin was observed focally when using the zinc(II)-specific agent, Gd-CP027, whereas little enhancement was detected when using gadofosveset. The contrast enhancement detected by Gd-CP027 increased in parallel with an increased dose of infused glucose. Serological measurements of C-peptide and insulin indicate that Gd-CP027, a high affinity zinc(II) contrast agent, potentiates their secretion only as a function of glucose stimulation. Taken in concert, this assay offers the possibility of detecting beta cell function in vivo non-invasively with MRI and underscores the role of zinc(II) in endocrine glucose metabolism.

Prospective study of gut hormone and metabolic changes after laparoscopic sleeve gastrectomy and Roux-en-Y gastric bypass

Background

Laparoscopic sleeve gastrectomy (SG) has surpassed Roux-en-Y gastric bypass (RYGB) as the most prevalent bariatric procedure worldwide. While RYGB and SG demonstrate equivalent short-term weight loss, long-term weight loss tends to be greater after RYGB. Differences in the effect of these procedures on gastrointestinal hormones that regulate energy homeostasis are felt to partially underlie differences in outcomes. The objective of this study was to prospectively quantify blood levels of gut hormones of energy and glucose homeostasis at one year follow up to delineate possible reasons for greater efficacy of RYGB over SG in achieving weight loss.

Methods

Patients undergoing SG (n = 19) and RYGB (n = 40) were studied before surgery and at 2,12, 26, and 52 weeks postoperatively. Blood samples drawn in the fasted state and after a liquid mixed meal were assayed at baseline, 26, and 52 weeks for peptide YY (PYY), glucagon-like peptide-1 (GLP-1), ghrelin, insulin, glucose, and leptin. Fasting and postprandial appetitive sensations were assessed by visual analog scale.

Results

At 1 year there was greater weight loss in RYGB compared with SG patients (30% vs 27%; P = 0.03). Area under the curve (AUC) after the mixed meal for PYY was greater in RYGB patients (P<0.001). RYGB patients had significant increases in GLP-1 AUC compared to baseline (P = 0.002). Ghrelin levels decreased only after SG compared to baseline (P<0.001) but were not significantly different from RYGB. There was a trend toward decreased sweet cravings in RYGB patients (P = 0.056).

Conclusions

Differences in gastrointestinal hormones that regulate energy and glucose homeostasis are a possible mechanism for greater efficacy of RYGB compared to SG.

Ongoing Inconsistencies in Weight Loss Reporting Following Bariatric Surgery: a Systematic Review

Weight loss is the primary outcome following bariatric surgery; however, its documentation within current literature is heterogeneous and poorly defined, limiting meaningful comparison between studies. Randomized controlled trials from 2012 to 2016 were identified using the Medline database through "Gastric bypass OR sleeve gastrectomy AND weight" search terms. A total of 73 studies with 5948 patients were included. Reporting of preoperative weight was done primarily using mean body mass index (BMI) (87.7%) and mean weight (65.8%). Postoperative weight reporting was more variable, with the most frequently reported measure being mean postoperative BMI (71.2%). Overall, nearly one third of all bariatric literature contained discrepancies that precluded meaningful meta-analysis. Reporting of weight loss following bariatric surgery is becoming increasingly diverse for both pre- and post-operative outcomes. Ongoing heterogeneity will continue to act as a barrier to meaningful comparison of bariatric outcomes until standardized reporting practices become adopted.

The Effects of Bariatric Surgery on Type 2 Diabetes in Asian Populations: a Meta-analysis of Randomized Controlled Trials

BACKGROUND

To evaluate the effects of bariatric surgery on patients with type 2 diabetes through comparing Asian and non-Asian populations according to follow-up time.

METHODS

In this meta-analysis of randomized controlled trials (RCTs), we searched PubMed databases for relevant articles. A meta-analysis was undertaken of 37 eligible RCTs.

RESULTS

Diabetes remission rates among Asian populations were similar to those of non-Asian populations at 1 year (95% confidence interval (CI) 0.519 [0.417, 0.619] vs 0.571 [0.316, 0.794], respectively) but were found to be higher in Asian populations at 2 years compared to non-Asian populations (95% CI 0.672 [0.469, 0.826] vs 0.563 [0.220, 0.855], respectively). Asian populations showed greater reductions in HbA1c (- 3.512 [- 2.726, - 4.299], - 3.001 [- 1.433, - 4.569], and - 3.345 [- 2.267, - 4.423]) than non-Asian populations (- 2.129 [- 1.821, - 2.438], - 2.301 [- 1.881, - 2.722], and - 2.107 [- 1.941, - 2.273]) at 1, 2, and 5 years, respectively. Asian populations also showed greater reductions of fasting plasma glucose than non-Asian populations, and these effects were prominent at 3- and 5-year follow-up (Asian populations, - 83.297 [- 73.264, - 93.331]; non-Asian populations, - 54.288 [- 37.409, - 71.166] at 3 years; Asian populations, - 99.014 [- 82.239, - 115.788]; non-Asian populations, - 45.756 [- 21.892, - 69.621] at 5 years).

CONCLUSIONS

Bariatric surgery is more successful in diabetes remission and glucose outcome improvement in Asian populations with type 2 diabetes than in non-Asian populations, even over long-term follow-up periods. Bariatric surgery can be considered an effective treatment option and may present an appropriate opportunity to improve the prognosis for Asian patients with type 2 diabetes.

Beta-cell sensitivity to insulinotropic gut hormones is reduced after gastric bypass surgery

OBJECTIVE

Postprandial hyperinsulinaemia after Roux-en Y gastric bypass (GB) has been attributed to rapid nutrient flux from the gut, and an enhanced incretin effect. However, it is unclear whether surgery changes islet cell responsiveness to regulatory factors. This study tested the hypothesis that β-cell sensitivity to glucagon like-peptide 1 (GLP-1) and glucose-dependent insulinotropic peptide (GIP) is attenuated after GB.

DESIGN

Ten non-diabetic subjects with GB, and 9 body mass index (BMI)-matched and age-matched non-surgical controls (CN) with normal glucose tolerance had blood glucose clamped at ~7.8 mM on three separate days. Stepwise incremental infusions of GLP-1 (15, 30, 60, 120 and 300 ng/LBkg/h), GIP (75, 150, 300, 600 and 1200 ng/LBkg/h) or saline were administered from 90 to 240 min and insulin secretion measured.

RESULTS

GB subjects had similar fasting glucose levels but lower fasting insulin compared with CN, likely due to increased insulin clearance. The average insulin secretion rates (ISRs) to 7.8 mM glucose were ~30% lower in GB relative to CN subjects. However, incretin-stimulated ISRs, adjusted for insulin sensitivity and glucose-stimulated insulin secretion, were even more attenuated in the GB subjects, by threefold to fourfold (AUC_{ISR(90-240 min)} during GLP-1 and GIP: 47±8 and 44±12 nmol in GB and 116±16 and 161±44 in CN; p<0.01).

CONCLUSION

After GB, the sensitivity of insulin secretion to both glucose and incretins is diminished.

Changing the Concept of Type 2 Diabetes: Beta Cell Workload Hypothesis Revisited

BACKGROUND

Despite a number of innovations in anti-diabetic drugs and substantial improvement in diabetes care, the number of people with diabetes continues to increase, suggesting further need to explore novel approaches to prevent diabetes. Type 2 diabetes (T2DM) is characterized by beta cell dysfunction and insulin resistance. However, insulin resistance, usually a consequence of obesity, is often emphasized and the role of beta cell dysfunction in T2DM is less appreciated.

OBJECTIVE AND RESULTS

This paper summarizes recent evidence showing the importance of beta cell dysfunction in T2DM and refines the "beta cell workload hypothesis", emphasizing the importance of beta cell preservation for the prevention and management of T2DM.

CONCLUSION

It is hoped that this novel concept will foster a better understanding of the pathophysiology of T2DM by not only medical staff and patients with diabetes, but also the general population, and encourage more people to adhere to a healthy lifestyle, eventually resulting in "stopping diabetes".

Contribution of endogenous glucagon-like peptide-1 to changes in glucose metabolism and islet function in people with type 2 diabetes four weeks after Roux-en-Y gastric bypass (RYGB)

Glucagon-Like Peptide-1 (GLP-1) is an insulin secretagogue which is elevated after Roux-en-Y Gastric Bypass (RYGB). However, its contribution to glucose metabolism after RYGB remains uncertain.

AIMS

We tested the hypothesis that GLP-1 lowers postprandial glucose concentrations and improves β-cell function after RYGB.

MATERIALS AND METHODS

To address these questions we used a labeled mixed meal to assess glucose metabolism and islet function in 12 obese subjects with type 2 diabetes studied before and four weeks after RYGB. During the post-RYGB study subjects were randomly assigned to receive an infusion of either saline or Exendin-9,39 a competitive antagonist of GLP-1 at its receptor. Exendin-9,39 was infused at 300 pmol/kg/min for 6 h. All subjects underwent RYGB for medically-complicated obesity.

RESULTS

Exendin-9,39 resulted in increased integrated incremental postprandial glucose concentrations (181 ± 154 vs. 582 ± 129 mmol per 6 h, p = 0.02). In contrast, this was unchanged in the presence of saline (275 ± 88 vs. 315 ± 66 mmol per 6 h, p = 0.56) after RYGB. Exendin-9,39 also impaired β-cell responsivity to glucose but did not alter Disposition Index (DI).

CONCLUSIONS

These data indicate that the elevated GLP-1 concentrations that occur early after RYGB improve postprandial glucose tolerance by enhancing postprandial insulin secretion.

MARCH: factors associated with weight loss in patients with newly diagnosed type 2 diabetes treated with acarbose or metformin

INTRODUCTION

In this secondary analysis of the Metformin and AcaRbose in Chinese as the initial Hypoglycaemic treatment (MARCH) trial, we evaluated what demographic and clinical factors were associated with reduction in weight. We also assessed the effects of acarbose and metformin treatment on weight reduction.

MATERIAL AND METHODS

We analyzed the demographic and clinical laboratory values from the 784 patients with type 2 diabetes of the MARCH study who were treated for 48 weeks with acarbose or metformin. We determined the association of the different parameters with a weight reduction of ≥ 2 kg in patients using univariate and multivariate analysis.

RESULTS

In patients treated with acarbose, males were less likely than females to lose ≥ 2 kg of weight (p = 0.025). Higher baseline HbA_1c levels and lower decreases from baseline in fasting plasma glucose (FPG) levels after 48 weeks of treatment were negatively associated with losing ≥ 2 kg of weight (both, p < 0.05). Higher baseline glucagon AUC was also positively associated with reducing weight by ≥ 2 kg (p = 0.010). In patients treated with metformin, change from baseline in whole body insulin sensitivity increased the odds of having a weight reduction of ≥ 2 kg (p = 0.014).

CONCLUSIONS

This study found that for both acarbose and metformin, control of FPG significantly impacted weight loss. Baseline AUC for glucagon in patients treated with acarbose and an increase of whole body insulin sensitivity after 48 weeks of treatment with metformin were important factors for weight reduction.

Roux-en-Y Gastric Bypass Is Associated With Hyperinsulinemia But Not Increased Maximal β-Cell Function

Context

Roux-en-Y gastric bypass (RYGB) is associated with postprandial hyperinsulinemia.

Objective

This study assessed whether increased blood insulin levels may be due to an increase in maximal β-cell function.

Design, Setting, and Participants

We performed a cross-sectional study at Columbia University Medical Center, New York, New York. Subjects without a history of diabetes were studied after surgery (n = 12) and were compared with nonsurgical controls (n = 10) who were mean matched for body mass index, insulin sensitivity, and hemoglobin A1c and with nonobese controls (n = 8).

Methods

Subjects underwent a mixed-meal tolerance test and on a separate day an intravenous glucose tolerance test followed by a hyperglycemic clamp (450 mg/dL; 25 mM blood glucose) and arginine stimulation. The main outcome measure was maximal insulin secretion quantified after arginine stimulation (AinsRmax).

Results

The RYGB group exhibited greater peak postprandial glucose levels and fourfold greater peak insulin levels than control groups; however, there were no significant differences in insulinogenic index or AinsRmax. Another finding was significantly greater postprandial glucagon levels in the RYGB group compared with controls.

Conclusions

Our results suggest that after RYGB, the increase in postprandial levels of insulin are not due to changes in maximal β-cell function but appear to be an appropriate response to altered nutrient flow and absorption.

Sleeve Gastrectomy and Roux-en-Y Gastric Bypass Achieve Similar Early Improvements in Beta-cell Function in Obese Patients with Type 2 Diabetes

Bariatric surgery is a treatment option for obese patients with type 2 diabetes mellitus (T2DM). Although sleeve gastrectomy (SG) is growing in favor, some randomized trials show less weight loss and HbA1c improvement compared with Roux-en-Y gastric bypass (RYGB). The study objective was to compare changes in beta-cell function with similar weight loss after SG and RYGB in obese patients with T2DM. Subjects undergoing SG or RYGB were studied with an intravenous glucose tolerance test before surgery and at 5–12% weight loss post-surgery. The primary endpoint was change in the disposition index (DI). Baseline BMI, HbA1c, and diabetes-duration were similar between groups. Mean total weight loss percent was similar (8.4% ± 0.4, p = 0.22) after a period of 21.0 ± 1.7 days. Changes in fasting glucose, acute insulin secretion (AIR), and insulin sensitivity (Si) were similar between groups. Both groups showed increases from baseline to post-surgery in DI (20.2 to 163.3, p = 0.03 for SG; 31.2 to 232.9, p = 0.02 for RYGB) with no significant difference in the change in DI between groups (p = 0.53). Short-term improvements in beta-cell function using an IVGTT were similar between SG and RYGB. It remains unclear if longer-term outcomes are better after RYGB due to greater weight loss and/or other factors.

Serum FABP4 concentrations decrease after Roux-en-Y gastric bypass but not after intensive medical management

BACKGROUND

Serum concentrations of fatty acid binding protein 4, an adipose tissue fatty acid chaperone, have been correlated with insulin resistance and cardiovascular risk factors. The objective of this study were to assess relationships among Roux-en-Y gastric bypass, intensive lifestyle modification and medical management protocol, fatty acid binding protein 4, and metabolic parameters in obese patients with severe type 2 diabetes mellitus; and to evaluate the relative contribution of abdominal subcutaneous adipose and visceral adipose to the secretion of fatty acid binding protein 4.

METHODS

Participants were randomly assigned to intensive lifestyle modification and medical management protocol (n = 29) or to intensive lifestyle modification and medical management protocol augmented with Roux-en-Y gastric bypass (n = 34). Relationships among fatty acid binding protein 4 and demographic characteristics, metabolic parameters, and 12-month changes in these values were examined. Visceral and subcutaneous adipose tissue explants from obese nondiabetic patients (n = 5) were obtained and treated with forskolin to evaluate relative secretion of fatty acid binding protein 4 in the different adipose tissue depots.

RESULTS

The intensive lifestyle modification and medical management protocol and Roux-en-Y gastric bypass cohorts had similar fasting serum fatty acid binding protein 4 concentrations at baseline. At 1 year, mean serum fatty acid binding protein 4 decreased by 42% in Roux-en-Y gastric bypass participants (P = .002) but did not change significantly in the intensive lifestyle modification and medical management protocol cohort. Percentage of weight change was not a significant predictor of 12-month fatty acid binding protein 4 within treatment arm or in multivariate models adjusted for treatment arm. In adipose tissue explants, fatty acid binding protein 4 was secreted similarly between visceral and subcutaneous adipose tissue.

CONCLUSION

After Roux-en-Y gastric bypass, fatty acid binding protein 4 is reduced 12 months after surgery but not after intensive lifestyle modification and medical management protocol in patients with type 2 diabetes mellitus. Fatty acid binding protein 4 was secreted similarly between subcutaneous and visceral adipose tissue explants.

Brown Adipose Tissue Energy Metabolism in Humans

The demonstration of metabolically active brown adipose tissue (BAT) in humans primarily using positron emission tomography coupled to computed tomography (PET/CT) with the glucose tracer 18-fluorodeoxyglucose (18FDG) has renewed the interest of the scientific and medical community in the possible role of BAT as a target for the prevention and treatment of obesity and type 2 diabetes (T2D). Here, we offer a comprehensive review of BAT energy metabolism in humans. Considerable advances in methods to measure BAT energy metabolism, including nonesterified fatty acids (NEFA), chylomicron-triglycerides (TG), oxygen, Krebs cycle rate, and intracellular TG have led to very good quantification of energy substrate metabolism per volume of active BAT in vivo. These studies have also shown that intracellular TG are likely the primary energy source of BAT upon activation by cold. Current estimates of BAT's contribution to energy expenditure range at the lower end of what would be potentially clinically relevant if chronically sustained. Yet, 18FDG PET/CT remains the gold-standard defining method to quantify total BAT volume of activity, used to calculate BAT's total energy expenditure. Unfortunately, BAT glucose metabolism better reflects BAT's insulin sensitivity and blood flow. It is now clear that most glucose taken up by BAT does not fuel mitochondrial oxidative metabolism and that BAT glucose uptake can therefore be disconnected from thermogenesis. Furthermore, BAT thermogenesis is efficiently recruited upon repeated cold exposure, doubling to tripling its total oxidative capacity, with reciprocal reduction of muscle thermogenesis. Recent data suggest that total BAT volume may be much larger than the typically observed 50-150 ml with 18FDG PET/CT. Therefore, the current estimates of total BAT thermogenesis, largely relying on total BAT volume using 18FDG PET/CT, may underestimate the true contribution of BAT to total energy expenditure. Quantification of the contribution of BAT to energy expenditure begs for the development of more integrated whole body in vivo methods.

What Has Bariatric Surgery Taught Us About the Role of the Upper Gastrointestinal Tract in the Regulation of Postprandial Glucose Metabolism?

The interaction between the upper gastrointestinal tract and the endocrine system is important in the regulation of metabolism and of weight. The gastrointestinal tract has a heterogeneous cellular content and comprises a variety of cells that elaborate paracrine and endocrine mediators that collectively form the entero-endocrine system. The advent of therapy that utilizes these pathways as well as the association of bariatric surgery with diabetes remission has (re-)kindled interest in the role of the gastrointestinal tract in glucose homeostasis. In this review, we will use the changes wrought by bariatric surgery to provide insights into the various gut-pancreas interactions that maintain weight, regulate satiety, and limit glucose excursions after meal ingestion.

Beta-cell sensitivity to glucose is impaired after gastric bypass surgery

AIMS

Patients who have undergone Roux-en-Y gastric bypass surgery (GB) have exaggerated postprandial insulin secretion, which has been attributed to increased meal glucose appearance and enhanced incretin effect. Here, we sought to determine β-cell glucose sensitivity in the absence of meal stimulation and insulinotropic gut factors.

MATERIALS AND METHODS

A total of 12 non-diabetic subjects with prior GB, and 7 matched non-surgical control subjects with normal glucose tolerance were studied. Blood glucose and insulin secretion rates were measured during a graded glucose infusion at increasing and then decreasing rates. Insulin sensitivity (S_I ) and glucose effectiveness (S_G ) were determined by the minimal model.

RESULTS

GB subjects had S_I comparable to that of control subjects. GB subjects had relative hyperglycaemia during the highest dose of glucose infusion associated with significantly reduced β-cell glucose sensitivity throughout both step-up (GB: 34 ± 6, CN: 82 ± 9 pmol min^-1 mM^-1 L, P < .0001) and step-down (GB: 31 ± 6, CN: 74 ± 9 pmol min^-1 mM^-1 L, P < .0001) phases of the glucose infusion. GB subjects also had reduced S_G (GB: 0.04 ± 0.00, CN: 0.07 ± 0.01 min^-1 , P = .004).

CONCLUSION

In the absence of enteric stimuli, β-cell sensitivity to changes in glycaemia is blunted among individuals with GB, indicating a significant shift in a fundamental property of β-cell function several years after surgery.

Lifestyle Intervention and Medical Management With vs Without Roux-en-Y Gastric Bypass and Control of Hemoglobin A1c, LDL Cholesterol, and Systolic Blood Pressure at 5 Years in the Diabetes Surgery Study

IMPORTANCE

The Roux-en-Y gastric bypass is effective in achieving established diabetes treatment targets, but durability is unknown.

OBJECTIVE

To compare durability of Roux-en-Y gastric bypass added to intensive lifestyle and medical management in achieving diabetes control targets.

DESIGN, SETTING, AND PARTICIPANTS

Observational follow-up of a randomized clinical trial at 4 sites in the United States and Taiwan, involving 120 participants who had a hemoglobin A1c (HbA1c) level of 8.0% or higher and a body mass index between 30.0 and 39.9 (enrolled between April 2008 and December 2011) were followed up for 5 years, ending in November 2016.

INTERVENTIONS

Lifestyle-intensive medical management intervention based on the Diabetes Prevention Program and LookAHEAD trials for 2 years, with and without (60 participants each) Roux-en-Y gastric bypass surgery followed by observation to year 5.

MAIN OUTCOMES AND MEASURES

The American Diabetes Association composite triple end point of hemoglobin A1c less than 7.0%, low-density lipoprotein cholesterol less than 100 mg/dL, and systolic blood pressure less than 130 mm Hg at 5 years.

RESULTS

Of 120 participants who were initially randomized (mean age, 49 years [SD, 8 years], 72 women [60%]), 98 (82%) completed 5 years of follow-up. Baseline characteristics were similar between groups: mean (SD) body mass index 34.4 (3.2) for the lifestyle-medical management group and 34.9 (3.0) for the gastric bypass group and had hemoglobin A1c levels of 9.6% (1.2) and 9.6% (1.0), respectively. At 5 years, 13 participants (23%) in the gastric bypass group and 2 (4%) in the lifestyle-intensive medical management group had achieved the composite triple end point (difference, 19%; 95% CI, 4%-34%; P = .01). In the fifth year, 31 patients (55%) in the gastric bypass group vs 8 (14%) in the lifestyle-medical management group achieved an HbA1c level of less than 7.0% (difference, 41%; 95% CI, 19%-63%; P = .002). Gastric bypass had more serious adverse events than did the lifestyle-medical management intervention, 66 events vs 38 events, most frequently gastrointestinal events and surgical complications such as strictures, small bowel obstructions, and leaks. Gastric bypass had more parathyroid hormone elevation but no difference in B12 deficiency.

CONCLUSIONS AND RELEVANCE

In extended follow-up of obese adults with type 2 diabetes randomized to adding gastric bypass compared with lifestyle and intensive medical management alone, there remained a significantly better composite triple end point in the surgical group at 5 years. However, because the effect size diminished over 5 years, further follow-up is needed to understand the durability of the improvement.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00641251.

The comprehensive summary of surgical versus non-surgical treatment for obesity: a systematic review and meta-analysis of randomized controlled trials

Background

Bariatric surgery has emerged as a competitive strategy for obese patients. However, its comparative efficacy against non-surgical treatments remains ill-defined, especially among nonseverely obese crowds. Therefore, we implemented a systematic review and meta-analysis in order for an academic addition to current literatures.

Methods

Literatures were retrieved from databases of PubMed, Web of Science, EMBASE and Cochrane Library. Randomized trials comparing surgical with non-surgical therapies for obesity were included. A Revised Jadad's Scale and Risk of Bias Summary were employed for methodological assessment. Subgroups analysis, sensitivity analysis and publication bias assessment were respectively performed in order to find out the source of heterogeneity, detect the outcome stability and potential publication bias.

Results

25 randomized trials were eligibly included, totally comprising of 1194 participants. Both groups displayed well comparability concerning baseline parameters (P > 0.05). The pooled results of primary endpoints (weight loss and diabetic remission) revealed a significant advantage among surgical patients rather than those receiving non-surgical treatments (P < 0.05). Furthermore, except for certain cardiovascular indicators, bariatric surgery was superior to conventional arms in terms of metabolic secondary parameters (P < 0.05). Additionally, the pooled outcomes were confirmed to be stable by sensitivity analysis. Although Egger's test (P < 0.01) and Begg's test (P<0.05) had reported the presence of publication bias among included studies, “Trim-and-Fill” method verified that the pooled outcomes remained stable.

Conclusion

Bariatric surgery is a better therapeutic option for weight loss, irrespective of follow-up duration, surgical techniques and obesity levels.

Bariatric Surgery: A Perspective for Primary Care

IN BRIEF Bariatric surgery is the most efficacious treatment for obesity, type 2 diabetes, and other obesity-related comorbidities. In this article, the authors review the current indications for bariatric surgery and discuss the most commonly performed procedures. They analyze medical outcomes of bariatric procedures by reviewing key prospective trials and discuss changes in physiology after these procedures. They conclude by discussing long-term management of bariatric patients by reviewing current guidelines for nutritional support and listing common complications related to these procedures.

The Gastrointestinal Tract as an Integrator of Mechanical and Hormonal Response to Nutrient Ingestion

Glucose tolerance after meal ingestion in vivo is the result of multiple processes that occur in parallel. Insulin secretion together with reciprocal inhibition of glucagon secretion contributes to glucose tolerance. However, other factors beyond glucose effectiveness and insulin action require consideration. The absorption of ingested nutrients and their subsequent systemic rate of appearance largely depend on the rate of delivery of nutrients to the proximal small intestine. This is determined by the integrated response of the upper gastrointestinal tract to a meal. While gastric emptying is probably the most significant component, other factors need to be considered. This review will examine all processes that could potentially alter the fraction and rate of appearance of ingested nutrients in the peripheral circulation. Several of these processes may be potential therapeutic targets for the prevention and treatment of diabetes. Indeed, there is increased interest in gastrointestinal contributions to nutritional homeostasis, as demonstrated by the advent of antidiabetes therapies that alter gastrointestinal motility, the effect of bariatric surgery on diabetes remission, and the potential of the intestinal microbiome as a modulator of human metabolism. The overall goal of this review is to examine current knowledge of the gastrointestinal contributions to metabolic control.

Metabolic Surgery in the Treatment Algorithm for Type 2 Diabetes: A Joint Statement by International Diabetes Organizations

BACKGROUND

Despite growing evidence that bariatric/metabolic surgery powerfully improves type 2 diabetes (T2D), existing diabetes treatment algorithms do not include surgical options.

AIM

The 2nd Diabetes Surgery Summit (DSS-II), an international consensus conference, was convened in collaboration with leading diabetes organizations to develop global guidelines to inform clinicians and policymakers about benefits and limitations of metabolic surgery for T2D.

METHODS

A multidisciplinary group of 48 international clinicians/scholars (75% nonsurgeons), including representatives of leading diabetes organizations, participated in DSS-II. After evidence appraisal (MEDLINE [1 January 2005-30 September 2015]), three rounds of Delphi-like questionnaires were used to measure consensus for 32 data-based conclusions. These drafts were presented at the combined DSS-II and 3rd World Congress on Interventional Therapies for Type 2 Diabetes (London, U.K., 28-30 September 2015), where they were open to public comment by other professionals and amended face-to-face by the Expert Committee.

RESULTS

Given its role in metabolic regulation, the gastrointestinal tract constitutes a meaningful target to manage T2D. Numerous randomized clinical trials, albeit mostly short/midterm, demonstrate that metabolic surgery achieves excellent glycemic control and reduces cardiovascular risk factors. On the basis of such evidence, metabolic surgery should be recommended to treat T2D in patients with class III obesity (BMI≥40 kg/m(2)) and in those with class II obesity (BMI 35.0-39.9 kg/m(2)) when hyperglycemia is inadequately controlled by lifestyle and optimal medical therapy. Surgery should also be considered for patients with T2D and BMI 30.0-34.9 kg/m(2) if hyperglycemia is inadequately controlled despite optimal treatment with either oral or injectable medications. These BMI thresholds should be reduced by 2.5 kg/m(2) for Asian patients.

CONCLUSIONS

Although additional studies are needed to further demonstrate long-term benefits, there is sufficient clinical and mechanistic evidence to support inclusion of metabolic surgery among antidiabetes interventions for people with T2D and obesity. To date, the DSS-II guidelines have been formally endorsed by 45 worldwide medical and scientific societies. Health care regulators should introduce appropriate reimbursement policies.

Metabolic Surgery in the Treatment Algorithm for Type 2 Diabetes: a Joint Statement by International Diabetes Organizations

BACKGROUND

Despite growing evidence that bariatric/metabolic surgery powerfully improves type 2 diabetes (T2D), existing diabetes treatment algorithms do not include surgical options.

AIM

The 2nd Diabetes Surgery Summit (DSS-II), an international consensus conference, was convened in collaboration with leading diabetes organizations to develop global guidelines to inform clinicians and policymakers about benefits and limitations of metabolic surgery for T2D.

METHODS

A multidisciplinary group of 48 international clinicians/scholars (75% nonsurgeons), including representatives of leading diabetes organizations, participated in DSS-II. After evidence appraisal (MEDLINE [1 January 2005-30 September 2015]), three rounds of Delphi-like questionnaires were used to measure consensus for 32 data-based conclusions. These drafts were presented at the combined DSS-II and 3rd World Congress on Interventional Therapies for Type 2 Diabetes (London, U.K., 28-30 September 2015), where they were open to public comment by other professionals and amended face-to-face by the Expert Committee.

RESULTS

Given its role in metabolic regulation, the gastrointestinal tract constitutes a meaningful target to manage T2D. Numerous randomized clinical trials, albeit mostly short/midterm, demonstrate that metabolic surgery achieves excellent glycemic control and reduces cardiovascular risk factors. On the basis of such evidence, metabolic surgery should be recommended to treat T2D in patients with class III obesity (BMI ≥40 kg/m²) and in those with class II obesity (BMI 35.0-39.9 kg/m²) when hyperglycemia is inadequately controlled by lifestyle and optimal medical therapy. Surgery should also be considered for patients with T2D and BMI 30.0-34.9 kg/m² if hyperglycemia is inadequately controlled despite optimal treatment with either oral or injectable medications. These BMI thresholds should be reduced by 2.5 kg/m² for Asian patients.

CONCLUSIONS

Although additional studies are needed to further demonstrate long-term benefits, there is sufficient clinical and mechanistic evidence to support inclusion of metabolic surgery among antidiabetes interventions for people with T2D and obesity. To date, the DSS-II guidelines have been formally endorsed by 45 worldwide medical and scientific societies. Health care regulators should introduce appropriate reimbursement policies.

Increased β-Cell Mass in Obese Rats after Gastric Bypass: A Potential Mechanism for Improving Glycemic Control

Background

Over the past few decades, bariatric surgery, especially Roux-en-Y gastric bypass (RYGB), has become widely considered the most effective treatment for morbid obesity. In most cases, it results in enhanced glucose management in patients with obesity and type 2 diabetes (T2D), which is observed before significant weight loss. However, what accounts for this effect remains controversial. To gain insight into the benefits of RYGB in T2D, we investigated changes in the β-Cell mass of obese rats following RYGB.

Material/Methods

RYGB or a sham operation was performed on obese rats that had been fed a high-fat diet (HFD) for 16 weeks. Then, the HFD was continued for 8 weeks in both groups. Additional normal chow diet (NCD) and obese groups were used as controls.

Results

In the present study, RYGB induced improved glycemic control and enhanced β-Cell function, which was reflected in a better glucose tolerance and a rapidly increased secretion of insulin and C-peptide after glucose administration. Consistently, rats in the RYGB group displayed increased β-Cell mass and islet numbers, which were attributed in part to increased glucagon-like peptide 1 levels following RYGB.

Conclusions

Our data indicate that RYGB can improve β-Cell function via increasing β-Cell mass, which plays a key role in improved glycemic control after RYGB.

Effect of Laparoscopic Sleeve Gastrectomy on Fasting Gastrointestinal, Pancreatic, and Adipose-Derived Hormones and on Non-Esterified Fatty Acids

BACKGROUND

Alterations in gastrointestinal, pancreatic, and adipose hormone levels may have a greater role in weight loss than initially appreciated. The laparoscopic sleeve gastrectomy (LSG) operation is now the most frequently performed bariatric operation in many countries, but there are relatively few data regarding its molecular effects. We sought to characterize the effect of LSG on fasting plasma levels of selected hormones and on non-esterified fatty acids (NEFA), and to compare these to levels in non-obese control individuals.

MATERIALS AND METHODS

The levels of nine plasma hormones were measured using a multiplex bead-based assay at baseline and at 3 months after operation in 11 obese patients undergoing LSG. NEFA levels were also measured. The levels were compared to those for 22 age- and sex-matched non-obese individuals.

RESULTS

At baseline, obese patients showed significantly higher expression of C-peptide, insulin, and leptin and significantly lower ghrelin, glucose-dependent insulinotropic peptide (GIP), and resistin compared to non-obese controls (p < 0.05). LSG resulted in a reduction in BMI from 42.5 ± 6.47 kg/m2 at operation to 35.2 ± 5.14 kg/m2 at 3 months (42 % mean excess weight loss, p < 0.001). LSG led to a significant decrease in ghrelin, glucagon-like peptide-1 (GLP-1), glucagon, leptin, plasminogen activator inhibitor-1 (PAI-1), and NEFA.

CONCLUSION

LSG induces marked early changes in the fasting levels of factors thought to be important regulators of obesity and metabolic health. These changes differ somewhat from the findings for operations with a malabsorptive component, suggesting that subtle differences exist in the mechanisms of weight loss between LSG and other bariatric operations.

Interorgan Crosstalk Contributing to β-Cell Dysfunction

Type 2 diabetes mellitus (T2DM) results from pancreatic β-cell failure in the setting of insulin resistance. In the early stages of this disease, pancreatic β-cells meet increased insulin demand by both enhancing insulin-secretory capacity and increasing β-cell mass. As the disease progresses, β-cells fail to maintain these compensatory responses. This involves both extrinsic signals and mediators intrinsic to β-cells, which adversely affect β-cells by impairing insulin secretion, decreasing proliferative capacities, and ultimately causing apoptosis. In recent years, it has increasingly been recognized that changes in circulating levels of various factors from other organs play roles in β-cell dysfunction and cellular loss. In this review, we discuss current knowledge of interorgan communications underlying β-cell failure during the progression of T2DM.

Bariatric surgery and type 2 diabetes: are there weight loss-independent therapeutic effects of upper gastrointestinal bypass?

Type 2 diabetes (T2D) is a major worldwide public health concern. Despite a large armamentarium of T2D medications, a large proportion of patients fail to achieve recommended treatment goals for glycemic control. Weight loss has profound beneficial effects on the metabolic abnormalities involved in the pathogenesis of T2D. Accordingly, bariatric surgery, which is the most effective available weight loss therapy, is also the most effective therapy for treating patients with T2D. Surgical procedures that bypass the upper gastrointestinal (UGI) tract are particularly effective in achieving partial and even complete remission of T2D, suggesting that UGI bypass has weight loss-independent effects on glycemic control. Although a number of hypotheses (e.g. a role for multiorgan insulin sensitivity, β-cell function, incretin response, the gut microbiome, bile acid metabolism, intestinal glucose metabolism and browning of adipose tissue) have been proposed to explain the potential unique effects of UGI tract bypass surgery, none has yet been adequately evaluated to determine therapeutic importance in patients with T2D. Here, we review the efficacy of UGI bypass surgery in treating T2D and the mechanisms that have been proposed to explain its potential weight loss-independent therapeutic effects.

Durability of Addition of Roux-en-Y Gastric Bypass to Lifestyle Intervention and Medical Management in Achieving Primary Treatment Goals for Uncontrolled Type 2 Diabetes in Mild to Moderate Obesity: A Randomized Control Trial

OBJECTIVE

We compared 3-year achievement of an American Diabetes Association composite treatment goal (HbA1c <7.0%, LDL cholesterol <100 mg/dL, and systolic blood pressure <130 mmHg) after 2 years of intensive lifestyle-medical management intervention, with and without Roux-en-Y gastric bypass, with one additional year of usual care.

RESEARCH DESIGN AND METHODS

A total of 120 adult participants, with BMI 30.0-39.9 kg/m(2) and HbA1c ≥8.0%, were randomized 1:1 to two treatment arms at three clinical sites in the U.S. and one in Taiwan. All patients received the lifestyle-medical management intervention for 24 months; half were randomized to also receive gastric bypass.

RESULTS

At 36 months, the triple end point goal was met in 9% of lifestyle-medical management patients and 28% of gastric bypass patients (P = 0.01): 10% and 19% lower than at 12 months. Mean (SD) HbA1c values at 3 years were 8.6% (3.5) and 6.7% (2.0) (P < 0.001). No lifestyle-medical management patient had remission of diabetes at 36 months, whereas 17% of gastric bypass patients had full remission and 19% had partial remission. Lifestyle-medical management patients used more medications than gastric bypass patients: mean (SD) 3.8 (3.3) vs. 1.8 (2.4). Percent weight loss was mean (SD) 6.3% (16.1) in lifestyle-medical management vs. 21.0% (14.5) in gastric bypass (P < 0.001). Over 3 years, 24 serious or clinically significant adverse events were observed in lifestyle-medical management vs. 51 with gastric bypass.

CONCLUSIONS

Gastric bypass is more effective than lifestyle-medical management intervention in achieving diabetes treatment goals, mainly by improved glycemic control. However, the effect of surgery diminishes with time and is associated with more adverse events.

Metabolic responses to xenin-25 are altered in humans with Roux-en-Y gastric bypass surgery

Xenin-25 (Xen) is a neurotensin-related peptide secreted by a subset of enteroendocrine cells located in the proximal small intestine. Many effects of Xen are mediated by neurotensin receptor-1 on neurons. In healthy humans with normal glucose tolerance (NGT), Xen administration causes diarrhea and inhibits postprandial glucagon-like peptide-1 (GLP-1) release but not insulin secretion. This study determines (i) if Xen has similar effects in humans with Roux-en-Y gastric bypass (RYGB) and (ii) whether neural pathways potentially mediate effects of Xen on glucose homeostasis. Eight females with RYGB and no history of type 2 diabetes received infusions with 0, 4 or 12pmol Xen/kg/min with liquid meals on separate occasions. Plasma glucose and gastrointestinal hormone levels were measured and insulin secretion rates calculated. Pancreatic polypeptide and neuropeptide Y levels were surrogate markers for parasympathetic input to islets and sympathetic tone, respectively. Responses were compared to those in well-matched non-surgical participants with NGT from our earlier study. Xen similarly increased pancreatic polypeptide and neuropeptide Y responses in patients with and without RYGB. In contrast, the ability of Xen to inhibit GLP-1 release and cause diarrhea was severely blunted in patients with RYGB. With RYGB, Xen had no statistically significant effect on glucose, insulin secretory, GLP-1, glucose-dependent insulinotropic peptide, and glucagon responses. However, insulin and glucose-dependent insulinotropic peptide secretion preceded GLP-1 release suggesting circulating GLP-1 does not mediate exaggerated insulin release after RYGB. Thus, Xen has unmasked neural circuits to the distal gut that inhibit GLP-1 secretion, cause diarrhea, and are altered by RYGB.

Metabolic Surgery in the Treatment Algorithm for Type 2 Diabetes: A Joint Statement by International Diabetes Organizations

BACKGROUND

Despite growing evidence that bariatric/metabolic surgery powerfully improves type 2 diabetes (T2D), existing diabetes treatment algorithms do not include surgical options.

AIM

The 2nd Diabetes Surgery Summit (DSS-II), an international consensus conference, was convened in collaboration with leading diabetes organizations to develop global guidelines to inform clinicians and policymakers about benefits and limitations of metabolic surgery for T2D.

METHODS

A multidisciplinary group of 48 international clinicians/scholars (75% nonsurgeons), including representatives of leading diabetes organizations, participated in DSS-II. After evidence appraisal (MEDLINE [1 January 2005-30 September 2015]), three rounds of Delphi-like questionnaires were used to measure consensus for 32 data-based conclusions. These drafts were presented at the combined DSS-II and 3rd World Congress on Interventional Therapies for Type 2 Diabetes (London, U.K., 28-30 September 2015), where they were open to public comment by other professionals and amended face-to-face by the Expert Committee.

RESULTS

Given its role in metabolic regulation, the gastrointestinal tract constitutes a meaningful target to manage T2D. Numerous randomized clinical trials, albeit mostly short/midterm, demonstrate that metabolic surgery achieves excellent glycemic control and reduces cardiovascular risk factors. On the basis of such evidence, metabolic surgery should be recommended to treat T2D in patients with class III obesity (BMI ≥40 kg/m(2)) and in those with class II obesity (BMI 35.0-39.9 kg/m(2)) when hyperglycemia is inadequately controlled by lifestyle and optimal medical therapy. Surgery should also be considered for patients with T2D and BMI 30.0-34.9 kg/m(2) if hyperglycemia is inadequately controlled despite optimal treatment with either oral or injectable medications. These BMI thresholds should be reduced by 2.5 kg/m(2) for Asian patients.

CONCLUSIONS

Although additional studies are needed to further demonstrate long-term benefits, there is sufficient clinical and mechanistic evidence to support inclusion of metabolic surgery among antidiabetes interventions for people with T2D and obesity. To date, the DSS-II guidelines have been formally endorsed by 45 worldwide medical and scientific societies. Health care regulators should introduce appropriate reimbursement policies.