Matched weight loss induced by sleeve gastrectomy or gastric bypass similarly improves metabolic function in obese subjects

Taste and odor interactions after metabolic surgery

Most patients report "taste" changes after undergoing metabolic surgeries. Yet, most studies that used validated sensory evaluation techniques, including ours, found no changes in perceived taste intensity from before to after surgery. However, we assessed participants with pure gustatory stimuli and after an overnight fast, which raises questions about whether patients' self-reported "taste" changes are due to conflating changes in retronasal smell/"flavor" with taste changes or whether they only manifest during the fed state. To investigate this, we conducted a cross-sectional study comparing sensory responses in women who underwent metabolic surgery 2 to 6 yr ago (n = 15) with 2 nonoperated control groups: one with a body mass index (BMI) equivalent (n = 15) and one with a healthy BMI (n = 15). Participants attended 2 sessions, one fed and one fasted. Using a sip-and-spit method, women tasted liquid samples containing gustatory and olfactory stimuli and puddings with varying fat content with and without nose clips. They used separate general labeled magnitude scales to rate their perceived intensity of taste, smell, flavor, and liking. Mixed ANOVAs indicated that the surgery and BMI equivalent groups rated retronasal smell intensity of coffee stronger than the healthy BMI group (P ≤ 0.015). However, there were no differences in taste/flavor intensity or liking ratings among groups. Additionally, feeding conditions did not significantly affect perceived intensity ratings. Our findings suggest that changes in the sensory-discriminatory component of taste or taste-odor interactions are not significant contributors to dietary modifications following metabolic surgery.

Differential effect of gastric bypass versus sleeve gastrectomy on insulinotropic action of endogenous incretins

OBJECTIVE

Prandial hyperinsulinemia after Roux-en-Y gastric bypass surgery (GB), and to lesser degree after sleeve gastrectomy (SG), has been attributed to rapid glucose flux from the gut and increased insulinotropic gut hormones. However, β-cell sensitivity to exogenous incretin is reduced after GB. This study examines the effect of GB versus SG on prandial glycemia and β-cell response to increasing concentrations of endogenous incretins.

METHODS

Glucose kinetics, insulin secretion rate (ISR), and incretin responses to 50-g oral glucose ingestion were compared between ten nondiabetic participants with GB versus nine matched individuals with SG and seven nonoperated normal glucose tolerant control individuals (CN) with and without administration of 200 mg of sitagliptin.

RESULTS

Fasting glucose and hormonal levels were similar among three groups. Increasing plasma concentrations of endogenous incretins by two- to three-fold diminished prandial glycemia and increased β-cell secretion in all three groups (p < 0.05), but insulin secretion per insulin sensitivity (i.e., disposition index) was increased only in GB (p < 0.05 for interaction). However, plot of the slope of ISR (from premeal to peak values) versus plasma glucagon-like peptide-1 concentration was smaller after GB compared with SG and CN.

CONCLUSIONS

After GB, increasing incretin activity augments prandial β-cell response whereas the β-cell sensitivity to increasing plasma concentrations of endogenous incretin is diminished.

Beta-cell function in type 2 diabetes (T2DM): Can it be preserved or enhanced?

Type 2 diabetes (T2DM) is a complex metabolic disorder manifested by hyperglycemia, insulin resistance, and deteriorating beta-cell function. A way to prevent progression of the disease might be to enhance beta-cell function and insulin secretion. However, most previous studies examined beta-cell function while patients were using glycemia-lowering agents without an adequate period off medications (washout). In the present review we focus on studies with a washout period. We performed a literature search (2010 to June 2021) using beta-cell function and enhancement. The evidence shows that beta-cell function can be enhanced. Bariatric surgery and very low calorie diets show improvement in beta-cell function in many individuals. In addition, use of glucagon-like peptide-1 receptor agonists for prolonged periods (3 years or more) can also lead to improvement of beta-cell function. Further research is needed to understand the mechanisms leading to improved beta-cell function and identify agents that could enhance beta-cell function in patients with T2DM.

Bariatric Surgery Alters the Postprandial Recovery From Hypoglycemia, Mediated by Cholinergic Signal

Roux-en-Y gastric bypass (GB) and sleeve gastrectomy (SG) surgeries increase prandial insulin and glucagon secretion but reduce the endogenous glucose production (EGP) response to hypoglycemia in comparison with control subjects who had not undergone gastric surgery (CN), suggesting that parasympathetic nervous system (PNS) plays a role. Here, we investigated the effect of acute PNS blockade on the post-meal counterregulatory response to insulin-induced hypoglycemia in GB and SG compared with CN. Glucose kinetics and islet cell secretion were measured in nine subjects without diabetes with GB and seven with SG and five CN during hyperinsulinemic-hypoglycemic clamp (∼3.2 mmol/L) combined with meal ingestion on two separate days with and without intravenous atropine infusion. Glucose and hormonal levels were similar at baseline and during steady-state hypoglycemia before meal ingestion in three groups and unaffected by atropine. Atropine infusion diminished prandial systemic appearance of ingested glucose (RaO) by 30%, EGP by 40%, and glucagon response to hypoglycemia by 90% in CN. In GB or SG, blocking PNS had no effect on the RaO or meal-induced hyperglucagonemia but increased EGP in SG without any effect in GB (P < 0.05 interaction). These findings indicate that cholinergic signal contributes to the recovery from hypoglycemia by meal consumption in humans. However, bariatric surgery dissipates PNS-mediated physiologic responses to hypoglycemia in the fed state.

ARTICLE HIGHLIGHTS

Rerouted gut after Roux-en-Y gastric bypass (GB) and, to a lesser degree, after sleeve gastrectomy (SG) leads to larger glucose excursion and lower nadir glucose, predisposing individuals to hypoglycemia. Despite prandial hyperglucagonemia, endogenous glucose production response to hypoglycemia is reduced after GB or SG. Parasympathetic nervous system (PNS) activity plays a key role in regulation of glucose kinetics and islet cell function. We examined the effect of acute PNS blockade on counterregulatory glucose and islet cell response to meal ingestion during insulin-induced hypoglycemia among GB, SG, and control subjects who had not had gastric surgery. Our findings demonstrate that cholinergic signal is critical in the recovery from hypoglycemia by meal ingestion in humans who have not had gastric surgery, although prandial PNS-mediated physiologic responses to hypoglycemia are differentially changed by GB and SG.

Roux-en-Y and One-Anastomosis Gastric Bypass Surgery Are Superior to Sleeve Gastrectomy in Lowering Glucose and Cholesterol Levels Independent of Weight Loss: a Propensity-Score Weighting Analysis

BACKGROUND

The superior effects of gastric bypass surgery in preventing cardiovascular diseases compared with sleeve gastrectomy are well-established. However, whether these effects are independent of weight loss is not known.

METHODS

In this retrospective cohort study, we compared the change in cardiometabolic risks of 1073 diabetic patients undergoing Roux-en-Y gastric bypass (RYGB) (n = 265), one-anastomosis gastric bypass (OAGB) (n = 619), and sleeve gastrectomy (SG) (n = 189) with equivalent weight loss from the Min-Shen General Hospital. Propensity score-weighting, multivariate regression, and matching were performed to adjust for baseline differences.

RESULTS

After 12 months, OAGB and, to a lesser extent, RYGB exhibited superior effects on glycemic control compared with SG in patients with equivalent weight loss. The effect was significant in patients with mild-to-modest BMI reduction but diminished in patients with severe BMI reduction. RYGB and OAGB had significantly greater effects in lowering total and low-density lipoprotein cholesterol than SG, regardless of weight loss. The results of matching patients with equivalent weight loss yielded similar results. The longer length of bypassed biliopancreatic (BP) limbs was correlated with a greater decrease in glycemic levels, insulin resistance index, lipids, C-reactive protein (CRP) levels, and creatinine levels in patients receiving RYBG. It was correlated with greater decreases in BMI, fasting insulin, insulin resistance index, and C-reactive protein levels in patients receiving OAGB.

CONCLUSION

Diabetic patients receiving OAGB and RYGB had lower glucose and cholesterol levels compared with SG independent of weight loss. Our results suggest diabetic patients with cardiovascular risk factors such as hypercholesterolemia to receive bypass surgery.

Heterogeneity in the effect of marked weight loss on metabolic function in women with obesity

BACKGROUNDThere is considerable heterogeneity in the effect of weight loss on metabolic function in people with obesity.METHODSWe evaluated muscle and liver insulin sensitivity, body composition, and circulating factors associated with insulin action before and after approximately 20% weight loss in women identified as "Responders" (n = 11) or "Non-responders" (n = 11), defined as the top (>75% increase) and bottom (<5% increase) quartiles of the weight loss-induced increase in glucose disposal rate (GDR) during a hyperinsulinemic-euglycemic clamp procedure, among 43 women with obesity (BMI: 44.1 ± 7.9 kg/m2).RESULTSAt baseline, GDR, which provides an index of muscle insulin sensitivity, and the hepatic insulin sensitivity index were more than 50% lower in Responders than Non-responders, but both increased much more after weight loss in Responders than Non-responders, which eliminated the differences between groups. Weight loss also caused greater decreases in intrahepatic triglyceride content and plasma adiponectin and PAI-1 concentrations in Responders than Non-responders and greater insulin-mediated suppression of plasma free fatty acids, branched-chain amino acids, and C3/C5 acylcarnitines in Non-responders than Responders, so that differences between groups at baseline were no longer present after weight loss. The effect of weight loss on total body fat mass, intra-abdominal adipose tissue volume, adipocyte size, and circulating inflammatory markers were not different between groups.CONCLUSIONThe results from our study demonstrate that the heterogeneity in the effects of marked weight loss on muscle and hepatic insulin sensitivity in people with obesity is determined by baseline insulin action, and reaches a ceiling when "normal" insulin action is achieved.TRIAL REGISTRATIONNCT00981500, NCT01299519, NCT02207777.FUNDINGNIH grants P30 DK056341, P30 DK020579, P30 DK052574, UL1 TR002345, and T32 HL13035, the American Diabetes Association (1-18-ICTS-119), the Longer Life Foundation (2019-011), and the Atkins Philanthropic Trust.

Evolution of the diagnostic value of "the sugar of the blood": hitting the sweet spot to identify alterations in glucose dynamics

In this paper, we provide an overview of the evolution of the definition of hyperglycemia during the past century and the alterations in glucose dynamics that cause fasting and postprandial hyperglycemia. We discuss how extensive mechanistic, physiological research into the factors and pathways that regulate the appearance of glucose in the circulation and its uptake and metabolism by tissues and organs has contributed knowledge that has advanced our understanding of different types of hyperglycemia, namely prediabetes and diabetes and their subtypes (impaired fasting plasma glucose, impaired glucose tolerance, combined impaired fasting plasma glucose, impaired glucose tolerance, type 1 diabetes, type 2 diabetes, gestational diabetes mellitus), their relationships with medical complications, and how to prevent and treat hyperglycemia.

The gut peptide Reg3g links the small intestine microbiome to the regulation of energy balance, glucose levels, and gut function

Changing composition of the gut microbiome is an important component of the gut adaptation to various environments, which have been implicated in various metabolic diseases including obesity and type 2 diabetes, but the mechanisms by which the microbiota influence host physiology remain contentious. Here we find that both diets high in the fermentable fiber inulin and vertical sleeve gastrectomy increase intestinal expression and circulating levels of the anti-microbial peptide Reg3g. Moreover, a number of beneficial effects of these manipulations on gut function, energy balance, and glucose regulation are absent in Reg3g knockout mice. Peripheral administration of various preparations of Reg3g improves glucose tolerance, and this effect is dependent on the putative receptor Extl3 in the pancreas. These data suggest Reg3g acts both within the lumen and as a gut hormone to link the intestinal microbiome to various aspects of host physiology that may be leveraged for novel treatment strategies.

Prandial hepatic glucose production during hypoglycemia is altered after gastric bypass surgery and sleeve gastrectomy

AIMS/HYPOTHESIS

Roux-en Y gastric bypass surgery (GB) and sleeve gastrectomy (SG) alter prandial glucose metabolism, producing lower nadir glucose values and predisposing susceptible individuals to prandial hypoglycemia. The glycemic phenotype of GB or SG is associated with prandial hyperinsulinemia and hyperglucagonemia along with an increased influx of ingested glucose. Following insulin-induced hypoglycemia, glucagon is the most important stimulus for hepatic glucose production (HGP). It is unclear whether prandial hyperglucagonemia after GB or SG changes HGP under hyperinsulinemic hypoglycemia conditions. This study examined the hypothesis that prandial glucose production is reduced after GB and SG during hypoglycemia.

METHODS

Glucose kinetics and islet-cell and gut hormone secretion during hyperinsulinemic (120 mU.m^-2.min^-1) hypoglycemic clamp (~3.2 mM) were measured before and after mixed meal ingestion in 9 non-diabetic subjects with GB, 7 with SG, and 5 matched non-operated controls (CN).

RESULTS

Systemic appearance of ingested glucose was faster in GB compared to SG, and in SG compared to CN (p < 0.05). Subjects with GB and SG had greater plasma glucagon levels after eating (AUC_Glucagon) compared to CN (p < 0.05). But prandial HGP response during insulin-induced hypoglycemia (AUC_HGP) was smaller and shorter in duration in surgical groups (p < 0.05). In the absence of meal stimuli, however, glucose counterregulatory response to hypoglycemia was comparable among the 3 groups during hyperinsulinemic clamp.

CONCLUSION

After bariatric surgery, prandial glucose counterregulatory response to hypoglycemia is impaired. Considering post-meal hyperglucagonemia after GB or SG the blunted HGP response suggests a lower sensitivity of liver to glucagon that can predispose to hypoglycemia in this population.

Nutrients handling after bariatric surgery, the role of gastrointestinal adaptation

Bariatric surgery determines a rearrangement of the gastrointestinal tract that influences nutrient handling and plays a role in the metabolic changes observed after surgery. Most of the changes depend on the accelerated gastric emptying observed in Roux-en-Y gastric bypass (RYGB) and, to a lesser extent, in sleeve gastrectomy (SG). The rapid delivery of meal into the jejunum, particularly after RYGB, contributes to the prompt appearance of glucose in peripheral circulation. Glucose increase is the principal determinant of GLP-1 increase with the consequent stimulation of insulin secretion, the latter balanced by a paradoxical glucagon increase that stimulates EGP to prevent hypoglycaemia. Protein digestion and amino acid absorption appear accelerated after RYGB but not after SG. After RYGB, the adaptation of the gut to the new condition participates to the metabolic change. The intestinal transit is delayed, the gut microbioma is changed, the epithelium becomes hypertrophic and increases the expression of glucose transporter and of the number of cell secreting hormones. These changes are not observed after SG. After RYGB-less after SG-bile acids (BA) increase, influencing glucose metabolism probably modulating FXR and TGR5 with an effect on insulin sensitivity. Muscle, hepatic and adipose tissue insulin sensitivity improve, and the gut reinforces the recovery of IS by enhancing glucose uptake and through the effect of the BA. The intestinal changes observed after RYGB result in a light malabsorption of lipid but not of carbohydrate and protein. In conclusion, functional and morphological adaptations of the gut after RYGB and SG activate inter-organs cross-talk that modulates the metabolic changes observed after surgery.Level of evidence Level V, narrative literature review.

Comparable Effects of Sleeve Gastrectomy and Roux-en-Y Gastric Bypass on Basal Fuel Metabolism and Insulin Sensitivity in Individuals with Obesity and Type 2 Diabetes

AIM

Bariatric surgery improves insulin sensitivity and glucose tolerance in obese individuals with type 2 diabetes (T2D), but there is a lack of data comparing the underlying metabolic mechanisms after the 2 most common surgical procedures Roux-en-Y gastric bypass surgery (RYGB) and sleeve gastrectomy (SG). This study was designed to assess and compare the effects of RYGB and SG on fuel metabolism in the basal state and insulin sensitivity during a two-step euglycemic glucose clamp.

MATERIALS AND METHODS

16 obese individuals with T2D undergoing either RYGB (n = 9) or SG (n = 7) were investigated before and 2 months after surgery, and 8 healthy individuals without obesity and T2D served as controls. All underwent a 2 h basal study followed by a 5 h 2-step hyperinsulinemic euglycemic glucose clamp at insulin infusion rates of 0.5 and 1.0 mU/kg LBM/min.

RESULTS

RYGB and SG induced comparable 15% weight losses, normalized HbA1c, fasting glucose, fasting insulin, and decreased energy expenditure. In parallel, we recorded similar increments (about 100%) in overall insulin sensitivity (M-value) and glucose disposal and similar decrements (about 50%) in endogenous glucose production and FFA levels during the clamp; likewise, basal glucose and insulin concentrations decreased proportionally.

CONCLUSION

Our data suggest that RYGB and SG improve basal fuel metabolism and two-step insulin sensitivity in the liver, muscle, and fat and seem equally favourable when investigated 2 months after surgery. This trial is registered with NCT02713555.

How Does Fat Mass Change in the First Year After Bariatric Surgery? A Systemic Review and Meta-Analysis

This systematic review and meta-analysis investigated the time-course effect of different type of bariatric surgeries (BS) up to 1 year post-surgery on fat mass (FM) and body fat percentage (BFP) in patients with morbid obesity. We searched PubMed, Scopus, EMBASE, ISI web of science, and Cochrane databases from October 2002 until May 2020 with no restriction in the English language, to find studies examining the effect of BS on FM (kg) and BFP (%) in morbid obese patients. Meta-analysis of 103 studies carried out on data of 18,166 and 14,575 morbid obese patients following BS, showed that BS was associated with a substantial decrease in FM and BFP, respectively, in 1 month (- 8.17 kg [95% CI - 9.07, - 7.27] and - 1.51% [95% CI - 2.56, - 0.46]), 3 months (- 15.75 [95% CI - 17.49, - 14.0] and - 4.90 [95% CI - 5.97, - 3.83]), 6 months (- 22.51 [95% CI - 23.93, - 21.09] and - 8.56% [95% CI - 9.63, - 7.49]), and 12 months (- 29.69 [95% CI - 31.3, - 28.09] and - 13.49% [95% CI - 14.52, - 12.40]) after the surgery. In conclusion, BS was associated with sustained declines in FM and BFP, from 1 to 12 months, with no indication of plateau phase post-surgery post-operatively. The present study emphasizes that post-bariatric care should have more focus on FM loss during 1-year post-surgery to identify the patients at risk for fat loss plateau.

The relation between postprandial glucagon-like peptide-1 release and insulin sensitivity before and after bariatric surgery in humans with class II/III obesity

BACKGROUND

Glucagon-like peptide-1 (GLP-1) receptor agonist treatment is beneficial for the human glucose metabolism, and GLP-1 secretion is greatly enhanced following Roux-en-Y gastric bypass (RYGB).

OBJECTIVES

To elucidate the relationship between GLP-1 concentrations and insulin sensitivity in subjects with class II/III obesity without diabetes and to assess the relation between GLP-1 and the improvements in glucose metabolism following RYGB.

SETTING

Clinical research facility in a university hospital.

METHODS

We recruited 35 patients scheduled for RYGB and assessed their plasma GLP-1, insulin, and glucose responses to a high-fat mixed meal. Basal and insulin-mediated glucose fluxes were determined during a 2-step hyperinsulinemic-euglycemic clamp with stable isotope-labeled tracers. Out of 35 subjects, 10 were studied both before surgery and at 1 year of follow-up.

RESULTS

Plasma GLP-1 increased following the high-fat mixed meal. Postprandial GLP-1 excursions correlated positively with hepatic and peripheral insulin sensitivity, but not with body mass index. At 1 year after RYGB, participants had lost 24% ± 6% of their body weight. Plasma GLP-1, insulin, and glucose levels peaked earlier and higher after the mixed meal. The positive association between the postprandial GLP-1 response and peripheral insulin sensitivity persisted.

CONCLUSIONS

Postprandial GLP-1 concentrations correlate with insulin sensitivity in subjects with class II/III obesity without diabetes before and 1 year after RYGB. Increased GLP-1 signaling in postbariatric patients may, directly or indirectly, contribute to the observed improvements in insulin sensitivity and metabolic health.

Hill Modified, a Novel Approach: Technique Description and Experience in Patients with Laparoscopic Sleeve Gastrectomy

BACKGROUND

Gastroesophageal reflux disease (GERD) is a common disease among patients with obesity, with an associated prevalence of 39 to 61% between the population who attends a bariatric surgery evaluation. Laparoscopic sleeve gastrectomy (LSG) has become a popular and valid option for obesity treatment, even though the literature is ambivalent regarding the increase or decrease in GERD after this surgery. Thus, it is necessary to propose new surgical techniques as a solution to GERD in patients with a concomitant LSG or with a history of it. Therefore, we present a modified technique based on Hill's gastropexy described originally in 1967.

OBJECTIVE

Describe and propose a surgical procedure for GERD management based on the Hill technique that can be applied in all patients who undergo an LSG or with a history of it.

METHODS

Retrospective observational study with a prospective database in which we described, Hill modified technique in a group of 16 patients with GERD who underwent this procedure concomitantly with an LSG or who presented with GERD after LSG with a 3-year follow-up. The surgical technique is based on an intra-abdominal esophageal length of a minimum of 3 cm and posterior fixation of the gastroesophageal junction to the crus.

RESULTS

Postoperative controls have shown satisfactory results in the control and management of GERD symptoms in this group of patients, with very few to no complications associated with the procedure and without reintervention or medication out of the standard protocol.

CONCLUSION

Hill modified technique can be used and presented as an option for GERD control in patients with LSG.

Clinical significance of diabetes control before metabolic surgery

BACKGROUND

Even though observational studies have suggested that poor preoperative diabetes control increases risk after major abdominal surgery, it is unclear whether this effect is seen in metabolic surgery patients.

OBJECTIVES

To determine whether poor preoperative diabetes control is associated with worse outcomes in patients with obesity and diabetes undergoing metabolic surgery.

SETTING

Metabolic and Bariatric Surgery Quality Improvement Project (MBSAQIP) database.

METHODS

Using the MBSAQIP 2017 and 2018 database and preoperative glycated hemoglobin (HbA1C) as a diabetes control surrogate, we examined the association between diabetes control and major outcomes of primary laparoscopic sleeve gastrectomy (SG) or Roux-en-Y gastric bypass (RYGB) in patients with diabetes and obesity. Multivariate logistic regression modeling examined five 30-day postoperative outcomes: composite serious complications (composite of 10 adverse events), composite infection (composite of 7 infectious complications), length of stay >5 days, reoperation, and readmission. Models were adjusted for multiple covariates.

RESULTS

In total, 26,674 patients with HbA1C data available within 30 days before metabolic surgery were included in the primary analysis and 35,884 patients with HbA1C data within 90 days before surgery were included in the sensitivity analysis. The mean body mass index (BMI) and preoperative HbA1C were 45.6 ± 8.2 kg/m² and 8.2 ± 2.7%, respectively. The incidence of 30-day postoperative infections and serious complications were 1.62% and 1.35%, respectively. Neither primary analysis nor sensitivity analysis demonstrated any association between higher HbA1C and worsening of 5 primary outcomes of interest. The odds ratio of an overall effect for SG was 1.01 (95% CI .98-1.03; P = .58) and for RYGB was .99 (95% CI .96-1.02; P = .41).

CONCLUSION

Suboptimal preoperative diabetes control is not associated with increased adverse events and should not delay metabolic surgery, as metabolic surgery is generally a safe procedure and intrinsically improves diabetes control.

Cardiovascular Risk Reduction Following Metabolic and Bariatric Surgery

Cardiovascular disease (CVD) remains a leading cause of morbidity and mortality in developed countries, with worsening pandemics of type 2 diabetes mellitus and obesity as major cardiovascular (CV) risk factors. Clinical trials of nonsurgical obesity treatments have not shown benefits in CVD, although recent diabetes trials have demonstrated major CV benefits. In many retrospective and prospective cohort studies, however, metabolic (bariatric) surgery is associated with substantial and reproducible CVD benefits. Despite a lack of prospective, randomized clinical trials, data suggest metabolic surgery may be the most effective modality for CVD risk reduction, likely through weight loss and weight loss-independent mechanisms.

Importance of Adipose Tissue NAD+ Biology in Regulating Metabolic Flexibility

Nicotinamide adenine dinucleotide (NAD+) is an essential coenzyme that regulates cellular energy metabolism in many cell types. The major purpose of the present study was to test the hypothesis that NAD+ in white adipose tissue (WAT) is a regulator of whole-body metabolic flexibility in response to changes in insulin sensitivity and with respect to substrate availability and use during feeding and fasting conditions. To this end, we first evaluated the relationship between WAT NAD+ concentration and metabolic flexibility in mice and humans. We found that WAT NAD+ concentration was increased in mice after calorie restriction and exercise, 2 enhancers of metabolic flexibility. Bariatric surgery-induced 20% weight loss increased plasma adiponectin concentration, skeletal muscle insulin sensitivity, and WAT NAD+ concentration in people with obesity. We next analyzed adipocyte-specific nicotinamide phosphoribosyltransferase (Nampt) knockout (ANKO) mice, which have markedly decreased NAD+ concentrations in WAT. ANKO mice oxidized more glucose during the light period and after fasting than control mice. In contrast, the normal postprandial stimulation of glucose oxidation and suppression of fat oxidation were impaired in ANKO mice. Data obtained from RNA-sequencing of WAT suggest that loss of NAMPT increases inflammation, and impairs insulin sensitivity, glucose oxidation, lipolysis, branched-chain amino acid catabolism, and mitochondrial function in WAT, which are features of metabolic inflexibility. These results demonstrate a novel function of WAT NAMPT-mediated NAD+ biosynthesis in regulating whole-body metabolic flexibility, and provide new insights into the role of adipose tissue NAD+ biology in metabolic health.

Effects of Diet versus Gastric Bypass on Metabolic Function in Diabetes

BACKGROUND

Some studies have suggested that in people with type 2 diabetes, Roux-en-Y gastric bypass has therapeutic effects on metabolic function that are independent of weight loss.

METHODS

We evaluated metabolic regulators of glucose homeostasis before and after matched (approximately 18%) weight loss induced by gastric bypass (surgery group) or diet alone (diet group) in 22 patients with obesity and diabetes. The primary outcome was the change in hepatic insulin sensitivity, assessed by infusion of insulin at low rates (stages 1 and 2 of a 3-stage hyperinsulinemic euglycemic pancreatic clamp). Secondary outcomes were changes in muscle insulin sensitivity, beta-cell function, and 24-hour plasma glucose and insulin profiles.

RESULTS

Weight loss was associated with increases in mean suppression of glucose production from baseline, by 7.04 μmol per kilogram of fat-free mass per minute (95% confidence interval [CI], 4.74 to 9.33) in the diet group and by 7.02 μmol per kilogram of fat-free mass per minute (95% CI, 3.21 to 10.84) in the surgery group during clamp stage 1, and by 5.39 (95% CI, 2.44 to 8.34) and 5.37 (95% CI, 2.41 to 8.33) μmol per kilogram of fat-free mass per minute in the two groups, respectively, during clamp stage 2; there were no significant differences between the groups. Weight loss was associated with increased insulin-stimulated glucose disposal, from 30.5±15.9 to 61.6±13.0 μmol per kilogram of fat-free mass per minute in the diet group and from 29.4±12.6 to 54.5±10.4 μmol per kilogram of fat-free mass per minute in the surgery group; there was no significant difference between the groups. Weight loss increased beta-cell function (insulin secretion relative to insulin sensitivity) by 1.83 units (95% CI, 1.22 to 2.44) in the diet group and by 1.11 units (95% CI, 0.08 to 2.15) in the surgery group, with no significant difference between the groups, and it decreased the areas under the curve for 24-hour plasma glucose and insulin levels in both groups, with no significant difference between the groups. No major complications occurred in either group.

CONCLUSIONS

In this study involving patients with obesity and type 2 diabetes, the metabolic benefits of gastric bypass surgery and diet were similar and were apparently related to weight loss itself, with no evident clinically important effects independent of weight loss. (Funded by the National Institutes of Health and others; ClinicalTrials.gov number, NCT02207777.).

Improvement in glycated hemoglobin A1C after laparoscopic Roux-en-Y gastric bypass and sleeve gastrectomy in an ethnically diverse population with diabetes

BACKGROUND

Obesity is a well-known risk factor for the development of type 2 diabetes. The efficacy of bariatric surgery in reducing weight with resulting improvement in type 2 diabetes has been reliably demonstrated.

OBJECTIVES

We investigated and compared the effects of laparoscopic Roux-en-Y gastric bypass (LRYGB) and laparoscopic sleeve gastrectomy (LSG) on glycated hemoglobin (HbA1C) levels in a predominantly Hispanic and black population.

SETTINGS

Community Hospital in New York, New York, United States.

METHODS

This is a retrospective review of a 5-year data from a single center where patients with diabetes who underwent LRYGB or LSG were included. HbA1C levels and body mass index were analyzed preoperatively and then annually postoperatively for up to 5 years. Improvements in HbA1C were compared between the 2 groups after adjusting for age, sex, race, and hypertension with linear mixed-effects or logistic regression models.

RESULTS

Of the 676 included patients, 84.8% were females and the mean age was 47 years. HbA1C levels decreased significantly (P < .05) in the entire group at 1 (21%), 2 (20%), 3 (20%), 4 (18%), and 5 (14%) years. Compared with LSG, LRYGB patients displayed greater improvement in HbA1C levels at 1 year (25% versus 17%, P = .001). The differences in the reduction of HbA1C between LRYGB and LSG for the other time intervals were not significant (P > .05), 24% versus 17% (2 yr), 22% versus 16% (3 yr), 22% versus 13% (4 yr), and 17% versus 10% (5 yr). Changes in body mass index were not correlated to changes in HbA1C at various study points.

CONCLUSION

Both LRYGB and LSG resulted in significant decreases in HbA1C levels and are correlated with changes in body mass index. LRYGB had the greatest effect at 1 year postoperatively. There was no significant difference in HbA1C reduction for LRYGB and LSG after 1 year postoperatively in this predominantly Hispanic and black cohort.

Bariatric Surgery Rapidly Decreases Cardiac Dietary Fatty Acid Partitioning and Hepatic Insulin Resistance Through Increased Intra-abdominal Adipose Tissue Storage and Reduced Spillover in Type 2 Diabetes

Reduced storage of dietary fatty acids (DFAs) in abdominal adipose tissues with enhanced cardiac partitioning has been shown in subjects with type 2 diabetes (T2D) and prediabetes. We measured DFA metabolism and organ partitioning using positron emission tomography with oral and intravenous long-chain fatty acid and glucose tracers during a standard liquid meal in 12 obese subjects with T2D before and 8-12 days after bariatric surgery (sleeve gastrectomy or sleeve gastrectomy and biliopancreatic diversion with duodenal switch). Bariatric surgery reduced cardiac DFA uptake from a median (standard uptake value [SUV]) 1.75 (interquartile range 1.39-2.57) before to 1.09 (1.04-1.53) after surgery (P = 0.01) and systemic DFA spillover from 56.7 mmol before to 24.7 mmol over 6 h after meal intake after surgery (P = 0.01), with a significant increase in intra-abdominal adipose tissue DFA uptake from 0.15 (0.04-0.31] before to 0.49 (0.20-0.59) SUV after surgery (P = 0.008). Hepatic insulin resistance was significantly reduced in close association with increased DFA storage in intra-abdominal adipose tissues (r = -0.79, P = 0.05) and reduced DFA spillover (r = 0.76, P = 0.01). We conclude that bariatric surgery in subjects with T2D rapidly reduces cardiac DFA partitioning and hepatic insulin resistance at least in part through increased intra-abdominal DFA storage and reduced spillover.

The jejunum is the key factor in insulin resistance

BACKGROUND

Biliopancreatic diversion (BPD) is more effective than Roux-en-Y gastric bypass (RYGB) on both insulin resistance and diabetes.

OBJECTIVES

Because the major difference between the 2 procedures resides in the length of jejunal bypass, we investigated the role of the jejunum in insulin resistance.

SETTING

University hospital in Italy.

METHODS

Insulin sensitivity (IS) and secretion were measured before and 4 weeks after RYGB or BPD in 16 patients. A translational study was also conducted in 6 pigs, by isolating a jejunal loop with its vascular and nerve supply (Thiry-Vella loop [TVL]). TVL was doubly stomatized and bowel continuity restored by a side-to-side jejuno-jejunostomy. At baseline and 4 weeks postoperatively a glucose bolus was injected either in the stomach or in the TVL. Whole-body IS and jejunal heat shock proteins (HSPs) were measured. Primary porcine hepatocyte cultures were incubated with plasma or individual HSPs.

RESULTS

Whole-body IS increased from 353.5 ± 26.7 to 442.0 ± 37.4 (P < .05) after RYGB and from 312.4 ± 14.9 to 441.2 ± 15.9 mL/m^-2/min^-1 (P < .001) after BPD. Hepatic IS was unchanged after RYGB, while it increased from .3 ± .01 to .4 ± .1 (μM/pM) - 1 (P < .01) after BPD. Total insulin secretion rate remained unchanged after RYGB but decreased (from 58.3 ± 23.6 to 33.1 ± 7.8 nmol/m^-2, P < .05) after BPD. Jejunectomy in pigs enhanced IS (.3 ± .01 versus .2 ± .01 mM/pM, P < .001), while injection of glucose into TVL reduced it (.1 ± .01 versus .3 ± .01 mM/pM, P < .0001). The jejunum secreted HSPs, Hsp70, and GRP78, which impaired insulin signaling in hepatocyte cultures.

CONCLUSIONS

This study shows that jejunal bypass in both humans and pigs improves IS. Injection of glucose into the TVL in pigs determines insulin resistance. In response to glucose, the jejunum secretes HSPs that impair insulin signaling.

Biliopancreatic Diversion Induces Greater Metabolic Improvement Than Roux-en-Y Gastric Bypass

Diabetes remission is greater after biliopancreatic diversion (BPD) than Roux-en-Y gastric bypass (RYGB) surgery. We used a mixed-meal test with ingested and infused glucose tracers and the hyperinsulinemic-euglycemic clamp procedure with glucose tracer infusion to assess the effect of 20% weight loss induced by either RYGB or BPD on glucoregulation in people with obesity (ClinicalTrials.gov number: NCT03111953). The rate of appearance of ingested glucose into the circulation was much slower, and the postprandial increases in plasma glucose and insulin concentrations were markedly blunted after BPD compared to after RYGB. Insulin sensitivity, assessed as glucose disposal rate during insulin infusion, was ∼45% greater after BPD than RYGB, whereas β cell function was not different between groups. These results demonstrate that compared with matched-percentage weight loss induced by RYGB, BPD has unique beneficial effects on glycemic control, manifested by slower postprandial glucose absorption, blunted postprandial plasma glucose and insulin excursions, and greater improvement in insulin sensitivity.

The Effects of Bariatric Surgery on Islet Function, Insulin Secretion, and Glucose Control

Although bariatric surgery was developed primarily to treat morbid obesity, evidence from the earliest clinical observations to the most recent clinical trials consistently demonstrates that these procedures have substantial effects on glucose metabolism. A large base of research indicates that bariatric surgeries such as Roux-en-Y gastric bypass (RYGB), vertical sleeve gastrectomy (VSG), and biliopancreatic diversion (BPD) improve diabetes in most patients, with effects frequently evident prior to substantial weight reduction. There is now unequivocal evidence from randomized controlled trials that the efficacy of surgery is superior to intensive life-style/medical management. Despite advances in the clinical understanding and application of bariatric surgery, there remains only limited knowledge of the mechanisms by which these procedures confer such large changes to metabolic physiology. The improvement of insulin sensitivity that occurs with weight loss (e.g., the result of diet, illness, physical training) also accompanies bariatric surgery. However, there is evidence to support specific effects of surgery on insulin clearance, hepatic glucose production, and islet function. Understanding the mechanisms by which surgery affects these parameters of glucose regulation has the potential to identify new targets for therapeutic discovery. Studies to distinguish among bariatric surgeries on key parameters of glucose metabolism are limited but would be of considerable value to assist clinicians in selecting specific procedures and investigators in delineating the resulting physiology. This review is based on literature related to factors governing glucose metabolism and insulin secretion after the commonly used RYGB and VSG, and the less frequently used BPD and adjustable gastric banding.

Changes in taste function and ingestive behavior following bariatric surgery

Bariatric surgery is the most effective treatment for severe obesity and its related comorbidities. Roux-en-Y Gastric Bypass (RYGB) and Sleeve Gastrectomy (SG) are currently the most popular weight-loss surgeries used worldwide. Following these surgeries, many patients self-report changes in taste perception and decreased preference for unhealthy foods. These reported changes might account for increased adherence to healthier diets and successful weight loss after surgeries. However, researchers have used a variety of methodologies to assess patients' reported changes andresults are discrepant. The goal of this review is to summarize the literature regarding changes to taste function and ingestive behavior following RYGB and SG to examine differences in findings by methodology (indirect vs. direct measurements). We focused our review around changes in sweets, fats, and alcohol because most of the documented changes in ingestive behavior post-surgery are related to changes in these dietary items. We found that studies using surveys and questionnaires generally find that subjects self-report changes in taste and decrease their preference and cravings for energy-dense foods (particularly, sweets and high-fats). However, studies using validated sensory techniques that include oral sampling or by using direct food intake measurements find little to no change in subjects' ability to perceive taste or their preference for energy-dense foods. Therefore, reported changes in taste and food preferences are unlikely to be explained by alterations in taste intensity and diet selection, and are rather related to changes in the rewarding value of food. Further, that RYGB, and likely SG, is associated with increased alcohol consumption and arisk to develop an alcohol use disorder) supports the notion that these surgeries alter central circuits of reward that are critical in the regulation of ingestive behavior.

Postprandial Nutrient Handling and Gastrointestinal Hormone Secretion After Roux-en-Y Gastric Bypass vs Sleeve Gastrectomy

BACKGROUND & AIMS

Sleeve gastrectomy (SG) and Roux-en-Y gastric bypass (RYGB) induce substantial weight loss and improve glycemic control in patients with type 2 diabetes, but it is not clear whether these occur via the same mechanisms. We compared absorption rates of glucose and protein, as well as profiles of gastro-entero-pancreatic hormones, in patients who had undergone SG or RYGB vs controls.

METHODS

We performed a cross-sectional study of 12 patients who had undergone sleeve gastrectomy, 12 patients who had undergone RYGB, and 12 individuals who had undergone neither surgery (controls), all in Denmark. Study participants were matched for body mass index, age, sex, and postoperative weight loss, and all had stable weights. They received continuous infusions of stable isotopes of glucose, glycerol, phenylalanine, tyrosine, and urea before and during a mixed meal containing labeled glucose and intrinsically phenylalanine-labeled caseinate. Blood samples were collected for 6 hours, at 10- to 60-minute intervals, and analyzed.

RESULTS

The systemic appearance of ingested glucose was faster after RYGB and SG vs controls; the peak glucose appearance rate was 64% higher after RYGB, and 23% higher after SG (both P < .05); the peak phenylalanine appearance rate from ingested casein was 118% higher after RYGB (P < .01), but similar between patients who had undergone SG and controls. Larger, but more transient increases in levels of plasma glucose and amino acids were accompanied by higher secretion of insulin, glucagon-like peptide 1, peptide YY, and cholecystokinin after RYGB, whereas levels of ghrelin were lower after SG, compared with RYGB and controls. Total 6-hour oral recovery of ingested glucose and protein was comparable among groups.

CONCLUSIONS

Postprandial glucose and protein absorption and gastro-entero-pancreatic hormone secretions differ after SG and RYGB. RYGB was characterized by accelerated absorption of glucose and amino acids, whereas protein metabolism after SG did not differ significantly from controls, suggesting that different mechanisms explain improved glycemic control and weight loss after these surgical procedures. ClinicalTrials.gov ID NCT03046186.

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.

Impact of body weight, low energy diet and gastric bypass on drug bioavailability, cardiovascular risk factors and metabolic biomarkers: protocol for an open, non-randomised, three-armed single centre study (COCKTAIL)

INTRODUCTION

Roux-en-Y gastric bypass (GBP) is associated with changes in cardiometabolic risk factors and bioavailability of drugs, but whether these changes are induced by calorie restriction, the weight loss or surgery per se, remains uncertain. The COCKTAIL study was designed to disentangle the short-term (6 weeks) metabolic and pharmacokinetic effects of GBP and a very low energy diet (VLED) by inducing a similar weight loss in the two groups.

METHODS AND ANALYSIS

This open, non-randomised, three-armed, single-centre study is performed at a tertiary care centre in Norway. It aims to compare the short-term (6 weeks) and long-term (2 years) effects of GBP and VLED on, first, bioavailability and pharmacokinetics (24 hours) of probe drugs and biomarkers and, second, their effects on metabolism, cardiometabolic risk factors and biomarkers. The primary outcomes will be measured as changes in: (1) all six probe drugs by absolute bioavailability area under the curve (AUC_oral/AUC_iv) of midazolam (CYP3A4 probe), systemic exposure (AUC_oral) of digoxin and rosuvastatin and drug:metabolite ratios for omeprazole, losartan and caffeine, levels of endogenous CYP3A biomarkers and genotypic variation, changes in the expression and activity data of the drug-metabolising, drug transport and drug regulatory proteins in biopsies from various organs and (2) body composition, cardiometabolic risk factors and metabolic biomarkers.

ETHICS AND DISSEMINATION

The COCKTAIL protocol was reviewed and approved by the Regional Committee for Medical and Health Research Ethics (Ref: 2013/2379/REK sørøst A). The results will be disseminated to academic and health professional audiences and the public via presentations at conferences, publications in peer-reviewed journals and press releases and provided to all participants.

TRIAL REGISTRATION NUMBER

NCT02386917.

Three-Year Follow-Up of Laparoscopic Reduced Port Sleeve Gastrectomy in 808 Consecutive Patients

BACKGROUND

Sleeve gastrectomy (SG) is a very popular technique for the treatment of morbid obesity. Less and less invasive laparoscopic approaches to SG have been proposed and shown to be safe and feasible.

OBJECTIVES

We developed a reduced port laparoscopic approach to sleeve gastrectomy (_RLSG) with the aim to further optimize the advantages of laparoscopy. Preliminary and safety profile of _RLSG as well as 3 years weight loss outcome are hereby discussed.

SETTING

University Hospital, Kuwait.

MATERIALS AND METHODS

All patients had morbid obesity with history of failure of conservative treatment. The _RLSG procedure was performed using only two skin incisions.

RESULTS

The analyzed population comprised 808 patients, including 642 women and 166 men. Mean age and BMI were 28.34 ± 8.37 and 41.09 ± 6.34, respectively. Mean operative time was 43 ± 20 min (range, 31-185). Mortality was nil. Overall morbidity rate was (4.5%). Three patients had postoperative leak (0.4%). Median duration of hospital stay was 2 days (range, 1-5). Mean percentage of excess weight loss (% EWL) was 23.18 ± 17.3% at 1 month, 55.08 ± 22.9% at 6 months, 82.6 ± 22.6% at 1 year, and 84.3 ± 22.4% at 3 years. Mean percentage total weight loss (%TWL) was 9.34% at 1 month, 22.42% at 6 months, and 34.57% at 1 year.

CONCLUSION

_RLSG is a safe and effective surgical option in patients with morbid obesity. Moreover, 3-year follow-up assessment confirmed adequate % EWL.

The influences of bariatric surgery on hemoglobin A1c in a sample of obese patients in Saudi Arabia

BACKGROUND

Although the frequency of surgical weight loss interventions has increased in Saudi Arabia, literature describing the clinical outcomes of bariatric surgery in Saudi Arabia is limited. This study aimed to assess whether weight loss intervention improves hemoglobin A1c (HbA1c) in obese patients and to identify its associated factors.

PATIENTS AND METHODS

A retrospective study was carried out on 318 patients with obesity class 1 or higher (body mass index [BMI] ≥ 30 kg/m²) who underwent laparoscopic sleeve gastrectomy or Roux-en-Y gastric bypass at King Abdulaziz Medical City in Riyadh, Saudi Arabia, between January 1, 2001 and March 31, 2017. Preoperatively and 12 months postoperatively, characteristics of patients were collected. BMI reduction was calculated, based on which patients were divided into three groups (0-9, 10-14, and >14 kg/m²).

RESULTS

The postoperative HbA1c was 5.83±0.9, while the baseline level was 6.74±2.1 (P=0.001). Fifty-eight of the 318 patients had diabetes. We observed significantly higher HbA1c in diabetic than in non-diabetic patients preoperatively, whereas an insignificantly different HbA1c was observed postoperatively. Among those who had minimal reduction in BMI (0-9 kg/m²), we observed significantly higher HbA1c in diabetic than in non-diabetic patients, whereas among those who had large reduction in BMI (10-14 kg/m²) and (>14 kg/m²), we observed insignificant differences in HbA1c in diabetic than in non-diabetic patients.

CONCLUSION

Being a diabetic patient was related to a significant reduction in HbA1c levels postoperatively. The study suggests that the reduction in HbA1c levels could be modified by BMI, wherein greater reduction in BMI leads to greater reduction in HbA1c levels.

[Is it possible to achieve sustained remission or cure of type 2 diabetes mellitus in the 21st century?]

A practitioner has a wide range of the hypoglycemic drugs for type 2 diabetes mellitus (T2DM) treatment, which can be used within a normal or near-normal range for long-term glycemic control. However, the question remains whether there are ways to achieve not only satisfactory glycemic control, but also T2DM remission (or even complete cure). The review presents an update on the concept of T2DM remission and describes the ways of its possible achievement with non-drug and drug treatments and surgery. The mechanisms of T2DM remission are given.

Biliopancreatic diversion with duodenal switch leads to better postprandial glucose level and beta cell function than sleeve gastrectomy in individuals with type 2 diabetes very early after surgery

OBJECTIVE

The aim of this study was to compare the short-term effect of sleeve gastrectomy (SG) and biliopancreatic diversion with duodenal switch (DS) in order to determine if exclusion of the upper gastrointestinal tract confers greater metabolic improvement, independent of weight loss.

METHODS

Standard meals were administered before and on day 3 and 4 after SG to assess insulin sensitivity, β-cell function and gastrointestinal hormone responses in matched normoglycemic (NG) and type 2 diabetes (T2D) participants. A third group of matched T2D participants who underwent DS with the same meal test administered prior to and 3days after surgery was also recruited.

RESULTS

Despite significant metabolic improvement, T2D participants failed to fully normalize insulin resistance and β-cell dysfunction 3 and 4days after SG. Our results demonstrate the superiority of DS over SG in terms of short-term improvement in postprandial glucose excursion and β-cell function 3days after the surgery, with similar improvement in hepatic insulin sensitivity.

CONCLUSION

Our findings support the notion that caloric restriction represents an important mechanism to explain the very early anti-diabetic effects observed after bariatric surgery. However, exclusion of the upper gastrointestinal tract also provides further metabolic improvements, possibly mediated by gastrointestinal hormonal responses and altered postprandial glucose absorption.

Early Metabolic Improvement After Bariatric Surgery: The First Steps Toward Remission of Type 2 Diabetes

The introduction of bariatric surgery into clinical practice in the 1980s was followed by a relatively long watch-and-wait period before the very rapid accumulation of scientific literature, over the past decade, concerning its clinical effectiveness and safety and its mechanisms of action in the treatment of obesity. These surgical procedures now emerge as the most effective therapeutic modality to induce long-term remission of type 2 diabetes. Recent research has shed light on the potential mechanisms leading to the profound improvement of glucose homeostasis following most bariatric surgery procedures. These mechanisms can be classified as weight loss dependent and independent, both playing sequential and then synergistic antidiabetes roles. Many groups, including our own, have contributed to our understanding of the relative roles of these mechanisms at differing time periods following these procedures. Here we summarize what we currently know about the mechanisms underlying the very rapid, weight loss-independent improvement in glucose homeostasis after bariatric surgery. Beyond its impact in the field of bariatric surgery, this new knowledge about the very rapid in vivo "reverse engineering" of type 2 diabetes actually provides unique insights into the intricate and complex mechanisms linking nutrition and obesity with the development of this disease.

Bariatric surgery for obesity and metabolic disorders: state of the art

Obesity is one of the most important public health conditions worldwide. Bariatric surgery for severe obesity is an effective treatment that results in the improvement and remission of many obesity-related comorbidities, as well as providing sustained weight loss and improvement in quality of life. Contemporary bariatric operations include Roux-en-Y gastric bypass, sleeve gastrectomy, adjustable gastric band and the duodenal switch. The vast majority of these procedures are now performed using laparoscopic technique, the main advantages of which include rapid recovery, the reduction of postoperative pain and the reduction of wound-related complications, compared with open surgery. Contemporary bariatric surgery is now safe, with a mortality of three in 1,000 patients; however, all bariatric operations are associated with their own unique short-term and long-term nutritional and procedural-related complications. Type 2 diabetes mellitus (T2DM) is the most studied metabolic disorder associated with obesity, with data demonstrating that improvement and remission of T2DM in patients with obesity is superior after bariatric surgery compared with conventional medical therapy. Bariatric surgery is now a part of some treatment algorithms for the medical management of patients with T2DM and severe obesity. New, minimally invasive and endoscopic devices for the treatment of obesity have now been approved in the USA, which will expand the treatment options for individuals with obesity.

Using the hyperinsulinemic euglycemic clamp to assess insulin sensitivity at 3 months following Roux-en-Y gastric bypass surgery in type 2 diabetes patients with BMI <35 kg/m2 in China

BACKGROUND

The aim of this study was to describe short-time effect of Roux-en-Y gastric bypass (RYGB) on insulin sensitivity (IS) of Chinese diabetes patients with body mass index (BMI) <35 kg/m² by hyperinsulinemic euglycemic clamp.

MATERIALS AND METHODS

We studied 15 type 2 diabete mellitus (T2DM) patients with BMI <35 kg/m², who underwent laparoscopical Roux-en-Y gastric bypass (LRYGB). Hyperinsulinemic-euglycemic clamp were performed at baseline and at 3 months after LRYGB.

RESULTS

The glucose disposal rate (M value) increased significantly at 3 months after RYGB (from 3.36 ± 1.26 mg kg^-1 min^-1 to 6.30 ± 1.3 mg kg^-1 min^-1, p < 0.001). The time to reach euglycemia at the hyperinsulinemic euglycemic clamp reduced remarkably from baseline to 3 months after RYGB (from 114.40 ± 6.11 min to 97.93 ± 8.57 min, p < 0.001). There was a marked reduction in value of HOMA-IR (from 4.47 ± 2.20 mg kg^-1 min^-1 to 2.10 ± 0.75 mg kg^-1 min^-1, p < 0.001). The parameters of body fat distribution (body weight, BMI, waist circumference, waist to hip radio) changed obviously after surgery. RYGB caused a significant improvement in fasting and postprandial plasma glucose and insulin, HbAc1. Preoperative M value and the time to reach steady-state correlated with changes of M and the time to reach steady-state at 3 months after RYGB.

CONCLUSION

Peripheral and hepatic IS improved remarkably at 3 months following RYGB, as an important mechanism for early improvement in T2DM patients with low BMI. And the time to reach euglycemia at the hyperinsulinemic euglycemic clamp may be an useful index of assessing insulin sensitivity. It is more reasonal to combine the time to reach euglycemia with M value for assessing IS.

Comparison of glucose homeostasis parameters between patients with high and low risk of diabetes at 6 weeks and 6 months after sleeve gastrectomy

BACKGROUND

The changes in glucose homeostasis after sleeve gastrectomy (SG) for patients with high (HRD) and low risk (LRD) of developing diabetes have not been investigated.

OBJECTIVE

To compare the glucose homeostasis parameters between patients with HRD and LRD after SG.

SETTING

University hospital in Greece.

METHODS

Thirteen patients were categorized as HRD (9 females, mean body mass index 46.3±1.6 kg/m²) and 10 as LRD (8 females, mean body mass index 45.4±1.7 kg/m²) based on a preoperative 2-hour oral glucose tolerance test (OGTT). OGTT was repeated 6 weeks and 6 months postoperatively. OGTT-derived indices of insulin secretion, insulin sensitivity, and β-cell function (oral disposition index [ODI]) were calculated.

RESULTS

Preoperatively, in the HRD group, fasting and postload glucose levels were higher and the ODIs were lower compared with those in the LRD group. Six weeks postoperatively, glucose levels and ODIs were not different between the 2 groups. However, 6 months postoperatively, the HRD group had demonstrated higher postload glucose levels and lower ODI (0-30) and ODI (0-120) compared with the LRD group. Six weeks postoperatively, insulin levels, early insulin secretion, and insulin resistance indices were decreased compared with preoperative levels only in the HRD group. Six months postoperatively, ODIs and insulin sensitivity indices improved in both groups compared with baseline.

CONCLUSION

Six months after SG, glucose levels and ODIs improved for both HRD and LRD patients; however, postprandial glucose levels and ODI (0-30) and ODI (0-120) in HRD patients did not return to LRD levels. Moreover, during the first 6 postoperative weeks, the changes in glucose homeostasis parameters compared with preoperative levels were different for HRD and LRD patients.

Short-term Effects of Laparoscopic Adjustable Gastric Banding Versus Roux-en-Y Gastric Bypass

OBJECTIVE

Bariatric surgery has been shown to have important long-term metabolic effects resulting in enhanced insulin sensitivity and improved glucose tolerance in patients with type 2 diabetes. The contribution of reduced caloric intake to these beneficial effects of surgery remains unclear. The aim of this study was to compare the short-term effects (1 week) of bariatric surgical procedures with a very low caloric intake (VLCI) on insulin sensitivity (IS) and insulin secretion (ISR) in nondiabetic obese subjects.

RESEARCH DESIGN AND METHODS

Twenty obese patients without diabetes (BMI 44.2 ± 0.7 kg/m²) were admitted to the clinic for 1 week. At baseline and 1 week after VLCI (600 kcal/day), subjects received a hyperinsulinemic-euglycemic clamp with tracer infusion to quantify endogenous glucose production (EGP), lipolysis (rate of appearance of glycerol [RaGlycerol]), peripheral insulin sensitivity (insulin-stimulated glucose disposal [M value] divided by the steady-state plasma insulin concentration [M/I]), hepatic insulin sensitivity (Hep-IS [= 1/(EGP ⋅ insulin)]), and adipose insulin sensitivity (Adipo-IS [= 1/(RaGlycerol ⋅ insulin)]). An intravenous glucose bolus was administered at the end of the insulin clamp to measure ISR and β-cell function (disposition index [DI]). Approximately 3 months later, patients were admitted for laparoscopic adjustable gastric banding (LAGB) (n = 10) or Roux-en-Y gastric bypass (RYGB) (n = 10), and were restudied 1 week after surgery under the same caloric regimen (600 kcal/day).

RESULTS

After 1 week of VLCI, patients lost 2.1 kg without significant changes in Hep-IS, Adipo-IS, M/I, or DI. RYGB and LAGB led to greater weight loss (5.5 and 5.2 kg, respectively) and to significant improvement in Hep-IS, EGP, and lipolysis. Only RYGB improved Adipo-IS and M/I. No change in ISR or DI was observed in either surgical group.

CONCLUSIONS

Bariatric surgery improves IS within 1 week. These metabolic effects were independent of caloric intake and more pronounced after RYGB compared with LAGB.

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.

Changes of insulin sensitivity and secretion after bariatric/metabolic surgery

Type 2 diabetes (T2D) is classically characterized by failure of pancreatic β-cell function and insulin secretion to compensate for a prevailing level of insulin resistance, typically associated with visceral obesity. Although this is usually a chronic, progressive disease in which delay of end-organ complications is the primary therapeutic goal for medical and behavioral approaches, several types of bariatric surgery, especially those that include intestinal bypass components, exert powerful antidiabetes effects to yield remission of T2D in most cases. It has become increasingly clear that in addition to the known benefits of acute caloric restriction and chronic weight loss to ameliorate T2D, bariatric/metabolic operations also engage a variety of weight-independent mechanisms to improve glucose homeostasis, enhancing insulin sensitivity and secretion to varying degrees depending on the specific operation. In this paper, we review the effects of Roux-en-Y gastric bypass, biliopancreatic diversion, and vertical sleeve gastrectomy on the primary determinants of glucose homeostasis: insulin sensitivity, insulin secretion, and, to the lesser extent that it is known, insulin-independent glucose disposal. A full understanding of these effects should help optimize surgical and device-based designs to provide maximal antidiabetes impact, and it holds the promise to identify targets for possible novel diabetes pharmacotherapeutics. These insights also contribute to the conceptual rationale for use of bariatric operations as "metabolic surgery," employed primarily to treat T2D, including among patients not obese enough to qualify for surgery based on traditional criteria related to high body mass index.

Changes in insulin sensitivity and secretion after sleeve gastrectomy

Background

Sleeve gastrectomy is indicated for the treatment of obesity and related co-morbidity including diabetes. The dynamic changes in insulin secretion and sensitivity after sleeve gastrectomy are unknown.

Methods

Whole-body insulin sensitivity was measured by the euglycaemic hyperinsulinaemic clamp technique, and insulin secretion by C-peptide deconvolution after an oral glucose tolerance test (OGTT), before and 3, 6 and 12 months after sleeve gastrectomy in morbidly obese subjects. The time course of glucagon-like peptide (GLP) 1, as a marker of insulin secretion following OGTT, was also assessed.

Results

Ten patients were included in the study. Median (range) baseline insulin sensitivity (M-value) increased from 84·0 (20·2–131·4) mmol per kg per min at baseline to 122·8 (99·0–179·3) mmol per kg per min at 12 months after surgery (P = 0·015). Fasting insulin sensitivity, measured by homeostatic model assessment of insulin resistance, which represents a surrogate index of hepatic insulin resistance, decreased from 3·3 (1·9–5·5) to 0·7 (0·5–1·1) mg/dl·µunits/ml (P &lt; 0·001). Total insulin secretion, measured as incremental area under the curve (AUC), after OGTT decreased from 360·4 (347·9–548·0) to 190·1 (10·1–252·0) mmol/l·180 min at 12 months (P = 0·011). The AUC for GLP-1 increased from 258·5 (97·5–552·6) to 5531·8 (4143·0–7540·9) pmol/l·180 min at 12 months after sleeve gastrectomy (P &lt; 0·001). In multiple regression analysis, 51 per cent of the M-value variability was explained by GLP-1 secretion.

Conclusion

Sleeve gastrectomy improved insulin sensitivity and reduced insulin secretion within 6 months after surgery. Although there was a correlation between insulin sensitivity and bodyweight, the major driver of the improvement in insulin sensitivity was GLP-1 secretion.

A prospective evaluation of the influence of three bariatric procedures on insulin resistance improvement. Should the extent of undiluted bile transit be considered a key postoperative factor altering glucose metabolism?

INTRODUCTION

Insulin resistance (IR), the essential step in development of type 2 diabetes mellitus (T2DM), resolves quickly after bariatric surgery, but the effectiveness depends on the type of the procedure. Although the long-term influence on IR improvement is well documented, the mechanisms of the ultra-fast response after restrictive and bypass procedures require explanation.

AIM

To determine IR evolution from the initial preparative period to 6 months after the operation, exposing the rapid postoperative response while comparing the 3 bariatric methods, with the belief that the metabolic effect may be correlated with anatomical combinations.

MATERIAL AND METHODS

From January to December, 2013, a cohort of severely obese, insulin resistant individuals recruited to the prospective study underwent laparoscopic sleeve gastrectomy (SG-30), Roux-en-Y gastric bypass (RYGB-30) and one-anastomosis gastric bypass (OAGB-30). Main laboratory parameters of glucose metabolism were evaluated in fasting patients preoperatively, 4 days and 1, 3 and 6 months after surgery.

RESULTS

Within the whole observation period the most significant improvement in homeostasis model assessment for IR (HOMA-IR) was observed in the first 4 days after each operation. The decrease of HOMA-IR was higher (p < 0.0001) in gastric bypass groups than in patients after SG (-41%). The difference between bypass groups favors OAGB over RYGB (63 vs. -56%, p = 0.0489).

CONCLUSIONS

Among all bariatric management factors, operation type is the most important in IR improvement. The significant difference in response after SG vs. RYGB and OAGB supports the concept of metabolic competence of duodeno-jejunal exclusion. Altered bile flow after duodeno-jejunal exclusion may be responsible for enhanced glucose metabolism improvement.

Primary silicone-banded laparoscopic sleeve gastrectomy: a pilot study

INTRODUCTION

Some degree of inadequate weight loss or recidivism is seen with all bariatric surgical approaches. To combat this, some authors have suggested placing a reinforcing ring around gastric bypass pouches or gastric sleeves. The aim of this study was to assess the initial feasibility and efficacy of silicone-banded laparoscopic sleeve gastrectomy (LSG).

MATERIALS AND METHODS

All cases of silicone-banded LSG performed at our center were retrospectively identified. Patient demographics, perioperative parameters, and postoperative outcomes were extracted and analyzed.

RESULTS

Thirteen patients (7 females, 6 males) were identified and analyzed. Preoperatively, patients had a mean age of 56.0 ± 8.3 years, a mean body mass index (BMI) of 53.7 ± 8.5 kg/m(2), and a median of seven comorbidities. All cases were completed laparoscopically by one surgeon, with a mean operative time of 140.7 ± 25.7 minutes and a mean estimated blood loss of 56.9 ± 30.6 mL. There were no mortalities. The only intraoperative complication was a respiratory arrest after extubation, and this patient recovered fully. Postoperatively, 2 patients (15.4%) experienced a complication: one had a pulmonary embolism requiring brief re-admission, and the other had a syncopal episode from a second-degree atrioventricular block. No long-term complications were encountered. One patient was lost to follow-up. At a median follow-up of 16 months (range, 6-27 months), the mean BMI of the cohort was 38.7 ± 7.9 kg/m(2), which corresponded to a mean excess weight loss (EWL) of 54.8 ± 19.6%.

CONCLUSIONS

This report provides initial evidence that silicone-banded LSG is feasible and can be performed with minimal morbidity and significant EWL at short-term follow-up.