Impact of different bariatric surgical procedures on insulin action and beta-cell function in type 2 diabetes

Physiological Appetite Regulation and Bariatric Surgery

Obesity remains a common metabolic disorder and a threat to health as it is associated with numerous complications. Lifestyle modifications and caloric restriction can achieve limited weight loss. Bariatric surgery is an effective way of achieving substantial weight loss as well as glycemic control secondary to weight-related type 2 diabetes mellitus. It has been suggested that an anorexigenic gut hormone response following bariatric surgery contributes to weight loss. Understanding the changes in gut hormones and their contribution to weight loss physiology can lead to new therapeutic treatments for weight loss. Two distinct types of neurons in the arcuate hypothalamic nuclei control food intake: proopiomelanocortin neurons activated by the anorexigenic (satiety) hormones and neurons activated by the orexigenic peptides that release neuropeptide Y and agouti-related peptide (hunger centre). The arcuate nucleus of the hypothalamus integrates hormonal inputs from the gut and adipose tissue (the anorexigenic hormones cholecystokinin, polypeptide YY, glucagon-like peptide-1, oxyntomodulin, leptin, and others) and orexigeneic peptides (ghrelin). Replicating the endocrine response to bariatric surgery through pharmacological mimicry holds promise for medical treatment. Obesity has genetic and environmental factors. New advances in genetic testing have identified both monogenic and polygenic obesity-related genes. Understanding the function of genes contributing to obesity will increase insights into the biology of obesity. This review includes the physiology of appetite control, the influence of genetics on obesity, and the changes that occur following bariatric surgery. This has the potential to lead to the development of more subtle, individualised, treatments for obesity.

Duodenal mucosal resurfacing with photodynamic therapy using methylene blue in a mouse model

BACKGROUND

The duodenum has emerged as a key player in metabolic diseases. The objective was to evaluate the safety and efficacy of intra-duodenal PDT using methylene blue in managing glycemic control and weight reduction.

METHODS

Optimal concentration of methylene blue and conditions for intra-duodenal PDT were determined through in vitro experiments. After injecting methylene blue into the duodenum, we performed intra-duodenal PDT. High-fat diet rats were used to assess the efficacy of intra-duodenal PDT through measures of oral glucose tolerance, insulin sensitivity, and weight change. Immunohistochemical staining was also conducted to examine GLP-1 and GIP-producing cells in the ileum and duodenum, respectively.

RESULTS

Introduodenal PDT reduced villous height of duodenum at 48 h, which was fully recovered at 30 days without complications. Rats treated with PDT showed significantly lower blood glucose levels with glucose loading and improved insulin sensitivity than rats in the sham-treatment group. The PDT group also had a significant reduction in body weight compared to the sham-treatment group at 30 days after intervention, although food intake was not significantly different between the two groups. Numbers of GLP-1 and GIP producing cells in the ileum and irradiated area were significantly higher in the PDT group than in the sham-treatment group.

CONCLUSIONS

Intra-duodenal PDT using methylene blue showed a feasible therapeutic modality in improving metabolic parameters. However, large animal experiments and mechanism studies are needed to determine the clinical relevance. The possibility of repeating this treatment every 30 days and its accompanying complications should be further studied.

A data-driven computational model for obesity-driven diabetes onset and remission through weight loss

Obesity is a major risk factor for the development of type 2 diabetes (T2D), where a sustained weight loss may result in T2D remission in individuals with obesity. To design effective and feasible intervention strategies to prevent or reverse T2D, it is imperative to study the progression of T2D and remission together. Unfortunately, this is not possible through experimental and observational studies. To address this issue, we introduce a data-driven computational model and use human data to investigate the progression of T2D with obesity and remission through weight loss on the same timeline. We identify thresholds for the emergence of T2D and necessary conditions for remission. We explain why remission is only possible within a window of opportunity and the way that window depends on the progression history of T2D, individual's metabolic state, and calorie restrictions. These findings can help to optimize therapeutic intervention strategies for T2D prevention or treatment.

Metabolic remission precedes possible weight regain after gastric bypass surgery

OBJECTIVE

Some patients regain weight to a variable extent from 1 year after Roux-en-Y gastric bypass surgery (RYGB), though rarely reaching preoperative values. The aim of the present study was to investigate whether, when, and to what extent metabolic remission occurs.

METHODS

Fasting metabolite and lipid profiles were determined in blood plasma collected from a nonrandomized intervention study involving 148 patients before RYGB and at 2, 12, and 60 months post RYGB. Both short-term and long-term alterations in metabolism were assessed. Anthropometric and clinical variables were assessed at all study visits.

RESULTS

This study found that the vast majority of changes in metabolite levels occurred during the first 2 months post RYGB. Notably, thereafter the metabolome started to return toward the presurgical state. Consequently, a close-to-presurgical metabolome was observed at the time when patients reached their lowest weight and glucose level. Lipids with longer acyl chains and a higher degree of unsaturation were altered more dramatically compared with shorter and more saturated lipids, suggesting a systematic and reversible lipid remodeling.

CONCLUSIONS

Remission of the metabolic state was observed prior to notable weight regain. Further and more long-term studies are required to assess whether the extent of metabolic remission predicts future weight regain and glycemic deterioration.

Reversing pancreatic β-cell dedifferentiation in the treatment of type 2 diabetes

The maintenance of glucose homeostasis is fundamental for survival and health. Diabetes develops when glucose homeostasis fails. Type 2 diabetes (T2D) is characterized by insulin resistance and pancreatic β-cell failure. The failure of β-cells to compensate for insulin resistance results in hyperglycemia, which in turn drives altered lipid metabolism and β-cell failure. Thus, insulin secretion by pancreatic β-cells is a primary component of glucose homeostasis. Impaired β-cell function and reduced β-cell mass are found in diabetes. Both features stem from a failure to maintain β-cell identity, which causes β-cells to dedifferentiate into nonfunctional endocrine progenitor-like cells or to trans-differentiate into other endocrine cell types. In this regard, one of the key issues in achieving disease modification is how to reestablish β-cell identity. In this review, we focus on the causes and implications of β-cell failure, as well as its potential reversibility as a T2D treatment.

Plasma short-chain fatty acid changes after bariatric surgery in patients with severe obesity

BACKGROUND

Obesity has reached epidemic dimensions in recent decades. Bariatric surgery (BS) is one of the most effective interventions for weight loss and metabolic improvement in patients with obesity. Short-chain fatty acids (SCFA) are gut microbiota-derived metabolites with a key role in body weight control and insulin sensitivity. Although BS is known to induce significant changes in the gut microbiota composition, its impact on the circulating levels of certain metabolites produced by the gut microbiota such as SCFA remains poorly understood.

OBJECTIVE

To determine the impact of BS on the circulating SCFA levels in patients with severe obesity.

SETTING

University hospital.

METHODS

An observational, prospective study was performed on 51 patients undergoing Roux-en-Y gastric bypass. Plasma samples were collected at baseline (1 day before surgery) and at 6 and 12 months after BS. Plasma SCFA levels were determined by liquid chromatography-mass spectrometry.

RESULTS

The results revealed significant changes in the circulating levels of SCFA after BS. A marked increase in propionate, butyrate, isobutyrate, and isovalerate levels and a decrease in acetate, valerate, hexanoate, and heptanoate levels were observed 12 months after BS. Furthermore, the changes in the levels of propionate, butyrate, and isobutyrate negatively correlated with changes in body mass index, while those of isobutyrate correlated negatively with changes in the homeostatic model assessment for insulin resistance index.

CONCLUSION

These results suggest that propionate, butyrate, and isobutyrate levels could be related to weight loss and improved insulin sensitivity in patients with severe obesity after BS.

Changes in quantity plant-based protein intake on type 2 diabetes remission in coronary heart disease patients: from the CORDIOPREV study

PURPOSE

Diabetes remission is a phenomenon described in the context of drastic weight loss due to bariatric surgery or low-calorie diets. Evidence suggests that increasing the intake of plant protein could reduce the risk of type 2 diabetes. We sought for association between changes in plant protein intake in the context of 2 healthy diets without weight loss nor glucose-lowering medication, and diabetes remission in coronary heart disease patients from the CORDIOPREV study.

METHODS

Newly diagnosed type 2 diabetes participants without glucose-lowering treatment were randomized to consume a Mediterranean or a low-fat diet. Type 2 diabetes remission was assessed with a median follow-up of 60 months according to the ADA recommendation. Information on patient's dietary intake was collected using food-frequency questionnaires. At first year of intervention, 177 patients were classified according to changes in plant protein consumption into those who increased or decreased its intake, in order to perform an observational analysis on the association between protein intake and diabetes remission.

RESULTS

Cox regression showed that patients increasing plant protein intake were more likely to remit from diabetes than those who decreased its intake (HR = 1.71(1.05-2.77)). The remission occurred mainly at first and second year of follow-up with diminished number of patients achieving remission in the third year onwards. The increase in plant protein was associated with lower intake of animal protein, cholesterol, saturated fatty acids, and fat, and with higher intake of whole grains, fibre, carbohydrates, legumes, and tree nuts.

CONCLUSION

These results support the need to increase protein intake of vegetal origin as dietary therapy to reverse type 2 diabetes in the context of healthy diets without weight loss.

Long-Term Results of Bariatric Surgery in Adolescents with at Least 5 Years of Follow-up: a Systematic Review and Meta-Analysis

OBJECTS

The purpose of this study was to investigate the long-term outcomes of bariatric surgery in adolescents with obesity by including studies with a follow-up of at least 5 years.

METHODS

PubMed, EMBASE, and CENTRAL were systematically searched. Studies that met the criteria were included in the analysis.

RESULT

We identified 29 cohort studies with a total population of 4970. Preoperative age ranged from 12 to 21 years; body mass index (BMI) ranged from 38.9 to 58.5 kg/m². Females were the predominant gender (60.3%). After at least 5-year of follow-up, the pooled BMI decline was 13.09 kg/m² (95%CI 11.75-14.43), with sleeve gastrectomy (SG) was 15.27 kg/m², Roux-en-Y gastric bypass (RYGB) was 12.86 kg/m², and adjustable gastric banding (AGB) was 7.64 kg/m². The combined remission rates of type 2 diabetes mellitus (T2DM), dyslipidemia, hypertension (HTN), obstructive sleep apnea (OSA), and asthma were 90.0%, 76.6%, 80.7%, 80.8%, and 92.5%, (95%CI 83.2-95.6, 62.0-88.9, 71.5-88.8, 36.4-100, and 48.5-100), respectively. Postoperative complications were underreported. Combined with the current study, we found a low level of postoperative complications. Iron and vitamin B12 deficiencies were the main nutritional deficiency complications identified so far.

CONCLUSION

For adolescents with severe obesity, bariatric surgery (especially RYGB and SG) is the independent and effective treatment option. After at least 5 years of follow-up, bariatric surgery in adolescents showed a desirable reduction in BMI and significant remission of T2DM, dyslipidemia, and HTN. Surgical and nutrition-related complications still need to be further explored by more long-term studies.

Glucose metabolism after bariatric surgery: implications for T2DM remission and hypoglycaemia

Although promising therapeutics are in the pipeline, bariatric surgery (also known as metabolic surgery) remains our most effective strategy for the treatment of obesity and type 2 diabetes mellitus (T2DM). Of the many available options, Roux-en-Y gastric bypass (RYGB) and vertical sleeve gastrectomy (VSG) are currently the most widely used procedures. RYGB and VSG have very different anatomical restructuring but both surgeries are effective, to varying degrees, at inducing weight loss and T2DM remission. Both weight loss-dependent and weight loss-independent alterations in multiple tissues (such as the intestine, liver, pancreas, adipose tissue and skeletal muscle) yield net improvements in insulin resistance, insulin secretion and insulin-independent glucose metabolism. In a subset of patients, post-bariatric hypoglycaemia can develop months to years after surgery, potentially reflecting the extreme effects of potent glucose reduction after surgery. This Review addresses the effects of bariatric surgery on glucose regulation and the potential mechanisms responsible for both the resolution of T2DM and the induction of hypoglycaemia.

Genetic and pharmacologic inhibition of ALDH1A3 as a treatment of β-cell failure

Type 2 diabetes (T2D) is associated with β-cell dedifferentiation. Aldehyde dehydrogenase 1 isoform A3 (ALHD1A3) is a marker of β-cell dedifferentiation and correlates with T2D progression. However, it is unknown whether ALDH1A3 activity contributes to β-cell failure, and whether the decrease of ALDH1A3-positive β-cells (A+) following pair-feeding of diabetic animals is due to β-cell restoration. To tackle these questions, we (i) investigated the fate of A+ cells during pair-feeding by lineage-tracing, (ii) somatically ablated ALDH1A3 in diabetic β-cells, and (iii) used a novel selective ALDH1A3 inhibitor to treat diabetes. Lineage tracing and functional characterization show that A+ cells can be reconverted to functional, mature β-cells. Genetic or pharmacological inhibition of ALDH1A3 in diabetic mice lowers glycemia and increases insulin secretion. Characterization of β-cells following ALDH1A3 inhibition shows reactivation of differentiation as well as regeneration pathways. We conclude that ALDH1A3 inhibition offers a therapeutic strategy against β-cell dysfunction in diabetes.

Sleeve Gastrectomy-Induced Weight Loss Increases Insulin Clearance in Obese Mice

Sleeve gastrectomy (SG) successfully recovers metabolic homeostasis in obese humans and rodents while also resulting in the normalization of insulin sensitivity and insulinemia. Reduced insulin levels have been attributed to lower insulin secretion and increased insulin clearance in individuals submitted to SG. Insulin degradation mainly occurs in the liver in a process controlled, at least in part, by the insulin-degrading enzyme (IDE). However, research has yet to explore whether liver IDE expression or activity is altered after SG surgery. In this study, C57BL/6 mice were fed a chow (CTL) or high-fat diet (HFD) for 10 weeks. Afterward, the HFD mice were randomly assigned to two groups: sham-surgical (HFD-SHAM) and SG-surgical (HFD-SG). Here, we confirmed that SG improves glucose-insulin homeostasis in obese mice. Additionally, SG reduced insulinemia by reducing insulin secretion, assessed by the analysis of plasmatic C-peptide content, and increasing insulin clearance, which was evaluated through the calculation of the plasmatic C-peptide:insulin ratio. Although no changes in hepatic IDE activity were observed, IDE expression was higher in the liver of HFD-SG compared with HFD-SHAM mice. These results indicate that SG may be helpful to counteract obesity-induced hyperinsulinemia by increasing insulin clearance, likely through enhanced liver IDE expression.

Endurance Training Improves GLP-1 Sensitivity and Glucose Tolerance in Overweight Women

Context and objective

Obesity and inactivity are risk factors for developing impaired glucose tolerance characterized by insulin resistance and reduced beta-cell function. The stimulatory effect of glucagon-like peptide 1 (GLP-1) on insulin secretion is also impaired in obese, inactive individuals. The aim of this study was to investigate whether endurance training influences beta-cell sensitivity to GLP-1.

Participants and intervention

Twenty-four female participants, age 46 ± 2 years, body mass index 32.4 ± 0.9 kg/m², and maximal oxygen consumption 24.7 ± 0.8 mL/kg/min participated in a 10-week exercise training study.

Methods

Beta-cell sensitivity to GLP-1 was assessed in a subset of participants (n = 6) during a 120-minute hyperglycemic glucose clamp (8.5 mM) including a 1-hour GLP-1 (7-36 amide) infusion (0.4 pmol/kg/min). Changes in glucose tolerance, body composition, and cardiorespiratory fitness were assessed by oral glucose tolerance tests (OGTTs), dual-energy X-ray absorptiometry scans, magnetic resonance scans, and maximal oxygen consumption (VO₂max) tests, respectively.

Results

The c-peptide response to infusion of GLP-1 increased 28 ± 3% (P < 0.05) toward the end of the hyperglycemic clamp. The insulin response remained unchanged. Training improved glucose tolerance and reduced GLP-1, insulin, and glucagon levels during the OGTTs. Training increased VO₂max (from 24.7 ± 0.8 to 27.0 ± 0.7 mL/kg/min; P < 0.05) and reduced visceral fat volume (from 4176 ± 265 to 3888 ± 266 cm³; P < 0.01).

Conclusion

Along with improved glycemic control, endurance training improved beta-cell sensitivity to GLP-1 in overweight women. The study was deemed not to constitute a clinical trial and was not registered as such.

Not Control but Conquest: Strategies for the Remission of Type 2 Diabetes Mellitus

A durable normoglycemic state was observed in several studies that treated type 2 diabetes mellitus (T2DM) patients through metabolic surgery, intensive therapeutic intervention, or significant lifestyle modification, and it was confirmed that the functional β-cell mass was also restored to a normal level. Therefore, expert consensus introduced the concept of remission as a common term to express this phenomenon in 2009. Throughout this article, we introduce the recently updated consensus statement on the remission of T2DM in 2021 and share our perspective on the remission of diabetes. There is a need for more research on remission in Korea as well as in Western countries. Remission appears to be prompted by proactive treatment for hyperglycemia and significant weight loss prior to irreversible β-cell changes. T2DM is not a diagnosis for vulnerable individuals to helplessly accept. We attempt to explain how remission of T2DM can be achieved through a personalized approach. It may be necessary to change the concept of T2DM towards that of an urgent condition that requires rapid intervention rather than a chronic, progressive disease. We must grasp this paradigm shift in our understanding of T2DM for the benefit of our patients as endocrine experts.

Effects of Diet, Lifestyle, Chrononutrition and Alternative Dietary Interventions on Postprandial Glycemia and Insulin Resistance

As years progress, we are found more often in a postprandial than a postabsorptive state. Chrononutrition is an integral part of metabolism, pancreatic function, and hormone secretion. Eating most calories and carbohydrates at lunch time and early afternoon, avoiding late evening dinner, and keeping consistent number of daily meals and relative times of eating occasions seem to play a pivotal role for postprandial glycemia and insulin sensitivity. Sequence of meals and nutrients also play a significant role, as foods of low density such as vegetables, salads, or soups consumed first, followed by protein and then by starchy foods lead to ameliorated glycemic and insulin responses. There are several dietary schemes available, such as intermittent fasting regimes, which may improve glycemic and insulin responses. Weight loss is important for the treatment of insulin resistance, and it can be achieved by many approaches, such as low-fat, low-carbohydrate, Mediterranean-style diets, etc. Lifestyle interventions with small weight loss (7–10%), 150 min of weekly moderate intensity exercise and behavioral therapy approach can be highly effective in preventing and treating type 2 diabetes. Similarly, decreasing carbohydrates in meals also improves significantly glycemic and insulin responses, but the extent of this reduction should be individualized, patient-centered, and monitored. Alternative foods or ingredients, such as vinegar, yogurt, whey protein, peanuts and tree nuts should also be considered in ameliorating postprandial hyperglycemia and insulin resistance. This review aims to describe the available evidence about the effects of diet, chrononutrition, alternative dietary interventions and exercise on postprandial glycemia and insulin resistance.

Biliopancreatic Diversion (BPD), Long Common Limb Revisional Biliopancreatic Diversion (BPD + LCL-R), Roux-en-Y Gastric Bypass [RYGB] and Sleeve Gastrectomy (SG) mediate differential quantitative changes in body weight and qualitative modifications in body composition: a 5-year study

AIMS

Bariatric surgeries induce profound weight loss (decrease in body mass index, BMI), through a decrease in fat mass (FM) and to a much lesser degree of fat-free mass (FFM). Some reports indicate that the weight which is lost after gastric bypass (RYGB) and sleeve gastrectomy (SG) is at least partially regained 2 years after surgery. Here we compare changes in BMI and body composition induced by four bariatric procedures in a 5 years follow-up study.

METHODS

We analyzed retrospectively modifications in BMI, FM and FFM obtained through Roux-en-Y gastric bypass (RYGB), sleeve gastrectomy (SG), biliopancreatic diversion (BPD) and a long common limb revisional biliopancreatic diversion (reduction of the gastric pouch and long common limb; BPD + LCL-R). Patients were evaluated at baseline and yearly for 5 years. Of the whole cohort of 565 patients, a subset of 180 patients had all yearly evaluations, while the remaining had incomplete evaluations. Setting University Hospital.

RESULTS

In a total of 180 patients evaluated yearly for 5 years, decrease in BMI and FM up to 2 years was more rapid with RYGB and SG than BPD and BPD + LCL-R; with RYGB and SG both BMI and FM slightly increased in the years 3-5. At 5 years, the differences were not significant. When analysing the differences between 2 and 5 years, BPD + LCL-R showed a somewhat greater effect on BMI and FM than RYGB, BPD and SG. Superimposable results were obtained when the whole cohort of 565 patients with incomplete evaluation was considered.

CONCLUSIONS

All surgeries were highly effective in reducing BMI and fat mass at around 2 years; with RYGB and SG both BMI and FM slightly increased in the years 3-5, while BPD and BPD + LCL-R showed a slight further decreases in the same time interval.

De Novo Glycine Synthesis Is Reduced in Adults With Morbid Obesity and Increases Following Bariatric Surgery

BACKGROUND

Glycine is a dietary non-essential amino acid that is low in obesity and increases following bariatric surgery. However, the exact mechanism responsible remains unclear and it is unknown whether hypoglycinemia is a cause or consequence of insulin resistance.

OBJECTIVE

Using multiple isotopically labeled tracers, we aimed to determine the underlying kinetic changes responsible for hypoglycinemia in obesity by: 1) Comparing glycine kinetics between participants with morbid obesity (BMI ≥ 32.5 kg/m²) to those with healthy weight (BMI < 25 kg/m²), and 2) Comparing glycine kinetic changes in participants with morbid obesity after bariatric surgery.

METHODS

[1,2-¹³C₂] glycine, [2,3,3-²H₃] serine, and [²H₅] phenylalanine were infused to compare the glycine kinetic parameters between 21 participants with morbid obesity and 21 controls with healthy weight. Participants with morbid obesity then underwent bariatric surgery and 17 were re-studied 6 months later. Data were analyzed by non-parametric methods and presented as median (interquartile range).

RESULTS

Compared to controls, participants with morbid obesity had significantly lower plasma glycine concentrations at 163 (153-171) vs. 201 (172-227) µmol/L and significantly reduced de novo glycine synthesis rate at 86.2 (64.5-111) vs.124 (103-159) µmol·kg LBM^-1·h¹, p < 0.001. Following surgery, body weight and insulin resistance decreased and this was accompanied by significant increases in plasma glycine concentration to 210 (191-243) µmol/L as well as the de novo glycine synthesis rate to 127 (98.3-133) µmol·kg LBM^-1·h^-1, p < 0.001 vs. baseline.

CONCLUSION

Hypoglycinemia in participants with morbid obesity was associated with impaired de novo glycine synthesis. The increase in plasma glycine concentration and de novo glycine synthesis plus the marked improvement in insulin resistance after bariatric surgery suggest that hypoglycinemia may be secondary to impaired glycine synthesis because of obesity-induced insulin resistance.

CLINICAL TRIAL REGISTRATION

[https://tinyurl.com/6wfj7yss], identifier [NCT04660513].

Diabetes remission is modulated by branched chain amino acids according to the diet consumed: from the CORDIOPREV study

SCOPE

BCAA plasma levels may be differentially associated with type 2 diabetes mellitus (T2DM) remission through the consumption of the Mediterranean diet (Med) and a low-fat (LF) diet.

METHODS

183 newly-diagnosed T2DM patients within the CORDIOPREV study were randomized to consume the Med or a LF diet. BCAA plasma levels (isoleucine, leucine and valine) were measured at fasting and after 120 min of an oral glucose tolerance test (OGTT) at the baseline of the study and after 5 y of the dietary intervention.

RESULTS

Isoleucine, leucine and valine plasma levels after 120 min of an OGTT in the Med diet (N = 80) were associated by COX analysis with T2DM remission: HR per SD (95%CI): 0.53 (0.37-0.77), 0.75 (0.52-1.08) and 0.61 (0.45-0.82), respectively; no association was found in patients who consumed a LF diet (N = 103). BCAA plasma levels combined in a score showed a HR of 3.33 (1.55-7.19) of T2DM remission for patients with a high score values in the Med diet, while in those with a LF diet no association was found.

CONCLUSION

Our study suggests that BCAA measurements potentially be used as a tool to select the most suitable diet to induce T2DM remission by nutritional strategies. This article is protected by copyright. All rights reserved.

Beta cell functionality and hepatic insulin resistance are major contributors to type 2 diabetes remission and starting pharmacological therapy: from CORDIOPREV randomized controlled trial

In order to assess whether previous hepatic IR (Hepatic-IR_fasting) and beta-cell functionality could modulate type 2 diabetes remission and the need for starting glucose-lowering treatment, newly-diagnosed type 2 diabetes participants who had never received glucose-lowering treatment (190 out of 1002) from the CORonary Diet Intervention with Olive oil and cardiovascular PREVention study (a prospective, randomized and controlled clinical trial), were randomized to consume a Mediterranean or a low-fat diet. Type 2 diabetes remission was defined according to the American Diabetes Association recommendation for levels of HbA1c, fasting plasma glucose and 2h plasma glucose after oral glucose tolerance test, and having maintained them for at least 2 consecutive years. Patients were classified according to the median of Hepatic-IR_fasting and beta-cell functionality, measured as the disposition index (DI) at baseline. Cox proportional hazards regression determined the potential for Hepatic-IR_fasting and DI indexes as predictors of diabetes remission and the probability of starting pharmacological treatment after a 5-year follow-up. Low-Hepatic-IR_fasting or high-DI patients had a higher probability of diabetes remission than high-Hepatic-IR_fasting or low-DI subjects (HR:1.79; 95% CI 1.06-3.05; and HR:2.66; 95% CI 1.60-4.43, respectively) after a dietary intervention with no pharmacological treatment and no weight loss. The combination of low-Hepatic-IR_fasting and high-DI presented the highest probability of remission (HR:4.63; 95% CI 2.00-10.70). Among patients maintaining diabetes, those with high- Hepatic-IR_fasting and low-DI showed the highest risk of starting glucose-lowering therapy (HR:3.24;95% CI 1.50-7.02). Newly-diagnosed type 2 diabetes patients with better beta-cell functionality and lower Hepatic-IR_fasting had a higher probability of type 2 diabetes remission in a dietary intervention without pharmacological treatment or weight loss, whereas among patients not achieving remission, those with worse beta-cell functionality and higher Hepatic-IR_fasting index had the highest risk of starting glucose-lowering treatment after 5 years of follow-up.

Laparoscopic Sleeve Gastrectomy has A Positive Impact on Subclinical Hypothyroidism Among Obese Patients: A Prospective Study

BACKGROUND

The effect of bariatric surgery on postoperative thyroid function remains incompletely understood. In this study, we aimed to evaluate the changes in thyroid functions after gastric sleeve operation for morbidly obese Egyptian patients.

METHODS

This was a prospective study that recruited 128 patients who underwent sleeve gastrectomy through the period from December 2016 to April 2020. We measured thyroid-stimulating hormone (TSH), free thyroxin (FT4), and free triiodothyronine. Subclinical hypothyroidism was defined by a TSH level > 4.5 mIU/L but a normal FT4 level. All patients were followed for 12 months after the procedure.

RESULTS

Preoperatively, 30 (23.4%) patients had subclinical hypothyroidism. The prevalence of subclinical hypothyroidism decreased significantly to reach 7.8% at the end of follow-up (p < 0.001). None of the patients developed de novo hypothyroidism at the end of follow-up. Patients with subclinical hypothyroidism were more likely to be females (p = 0.037) and had significantly higher waist circumference (p < 0.001), DBP (p = 0.02), serum cholesterol (p < 0.001), and serum triglyceride (p < 0.001). However, patients with subclinical hypothyroidism at the end of follow-up had significantly higher BMI at the end of the sixth month (p = 0.048). Similarly, patients with subclinical hypothyroidism at the end of follow-up had significantly higher serum cholesterol (p = 0.002), LDL, (p = 0.038), and serum triglyceride (p < 0.001) at the end of the sixth months of follow-up. A similar trend was noted at the end of the 12th month. The preoperative value of serum TSH correlated significantly with serum cholesterol and triglyceride levels.

CONCLUSION

The positive effect of the LSG procedure on the hypothyroid bariatric population, including enhanced thyroid function, was demonstrated.

Weight loss after Roux-En-Y gastric bypass surgery reveals skeletal muscle DNA methylation changes

BACKGROUND

The mechanisms of weight loss and metabolic improvements following bariatric surgery in skeletal muscle are not well known; however, epigenetic modifications are likely to contribute. The aim of our study was to investigate skeletal muscle DNA methylation after weight loss induced by Roux-en-Y gastric bypass (RYGB) surgery. Muscle biopsies were obtained basally from seven insulin-resistant obese (BMI > 40 kg/m²) female subjects (45.1 ± 3.6 years) pre- and 3-month post-surgery with euglycemic hyperinsulinemic clamps to assess insulin sensitivity. Four lean (BMI < 25 kg/m²) females (38.5 ± 5.8 years) served as controls. We performed reduced representation bisulfite sequencing next generation methylation on DNA isolated from the vastus lateralis muscle biopsies.

RESULTS

Global methylation was significantly higher in the pre- (32.97 ± 0.02%) and post-surgery (33.31 ± 0.02%) compared to the lean (30.46 ± 0.02%), P < 0.05. MethylSig analysis identified 117 differentially methylated cytosines (DMCs) that were significantly altered in the post- versus pre-surgery (Benjamini-Hochberg q < 0.05). In addition, 2978 DMCs were significantly altered in the pre-surgery obese versus the lean controls (Benjamini-Hochberg q < 0.05). For the post-surgery obese versus the lean controls, 2885 DMCs were altered (Benjamini-Hochberg q < 0.05). Seven post-surgery obese DMCs were normalized to levels similar to those observed in lean controls. Of these, 5 were within intergenic regions (chr11.68,968,018, chr16.73,100,688, chr5.174,115,531, chr5.1,831,958 and chr9.98,547,011) and the remaining two DMCs chr17.45,330,989 and chr14.105,353,824 were within in the integrin beta 3 (ITGB3) promoter and KIAA0284 exon, respectively. ITGB3 methylation was significantly decreased in the post-surgery (0.5 ± 0.5%) and lean controls (0 ± 0%) versus pre-surgery (13.6 ± 2.7%, P < 0.05). This decreased methylation post-surgery was associated with an increase in ITGB3 gene expression (fold change + 1.52, P = 0.0087). In addition, we showed that ITGB3 promoter methylation in vitro significantly suppressed transcriptional activity (P < 0.05). Transcription factor binding analysis for ITGB3 chr17.45,330,989 identified three putative transcription factor binding motifs; PAX-5, p53 and AP-2alphaA.

CONCLUSIONS

These results demonstrate that weight loss after RYGB alters the epigenome through DNA methylation. In particular, this study highlights ITGB3 as a novel gene that may contribute to the metabolic improvements observed post-surgery. Future additional studies are warranted to address the exact mechanism of ITGB3 in skeletal muscle.

Chronic peptide-based GIP receptor inhibition exhibits modest glucose metabolic changes in mice when administered either alone or combined with GLP-1 agonism

Combinatorial gut hormone therapy is one of the more promising strategies for identifying improved treatments for metabolic disease. Many approaches combine the established benefits of glucagon-like peptide-1 (GLP-1) agonism with one or more additional molecules with the aim of improving metabolic outcomes. Recent attention has been drawn to the glucose-dependent insulinotropic polypeptide (GIP) system due to compelling pre-clinical evidence describing the metabolic benefits of antagonising the GIP receptor (GIPR). We rationalised that benefit might be accrued from combining GIPR antagonism with GLP-1 agonism. Two GIPR peptide antagonists, GIPA-1 (mouse GIP(3–30)NH2) and GIPA-2 (NαAc-K10[γEγE-C16]-Arg18-hGIP(5–42)), were pharmacologically characterised and both exhibited potent antagonist properties. Acute in vivo administration of GIPA-1 during an oral glucose tolerance test (OGTT) had negligible effects on glucose tolerance and insulin in lean mice. In contrast, GIPA-2 impaired glucose tolerance and attenuated circulating insulin levels. A mouse model of diet-induced obesity (DIO) was used to investigate the potential metabolic benefits of chronic dosing of each antagonist, alone or in combination with liraglutide. Chronic administration studies showed expected effects of liraglutide, lowering food intake, body weight, fasting blood glucose and plasma insulin concentrations while improving glucose sensitivity, whereas delivery of either GIPR antagonist alone had negligible effects on these parameters. Interestingly, chronic dual therapy augmented insulin sensitizing effects and lowered plasma triglycerides and free-fatty acids, with more notable effects observed with GIPA-1 compared to GIPA-2. Thus, the co-administration of both a GIPR antagonist with a GLP1 agonist uncovers interesting beneficial effects on measures of insulin sensitivity, circulating lipids and certain adipose stores that seem influenced by the degree or nature of GIP receptor antagonism.

Identification of Proteins Associated with the Early Restoration of Insulin Sensitivity After Biliopancreatic Diversion

CONTEXT

Insulin resistance (IR) is a risk factor for type 2 diabetes, diabetic kidney disease, cardiovascular disease and nonalcoholic steatohepatitis. Biliopancreatic diversion (BPD) is the most effective form of bariatric surgery for improving insulin sensitivity.

OBJECTIVE

To identify plasma proteins correlating with the early restoration of insulin sensitivity after BPD.

DESIGN

Prospective single-center study including 20 insulin-resistant men with morbid obesity scheduled for BPD. Patient characteristics and blood samples were repeatedly collected from baseline up to 4 weeks postsurgery. IR was assessed by homeostatic model assessment for insulin resistance (HOMA-IR), Matsuda Index, and by studying metabolic profiles during meal tolerance tests. Unbiased proteomic analysis was performed to identify plasma proteins altered by BPD. Detailed plasma profiles were made on a selected set of proteins by targeted multiple reaction monitoring mass spectrometry (MRM/MS). Changes in plasma proteome were evaluated in relation to metabolic and inflammatory changes.

RESULTS

BPD resulted in improved insulin sensitivity and reduced body weight. Proteomic analysis identified 29 proteins that changed following BPD. Changes in plasma levels of afamin, apolipoprotein A-IV (ApoA4), and apolipoprotein A-II (ApoA2) correlated significantly with changes in IR.

CONCLUSION

Circulating levels of afamin, ApoA4, and ApoA2 were associated with and may contribute to the rapid improvement in insulin sensitivity after BPD.

Effects of an intensive lifestyle intervention on the underlying mechanisms of improved glycaemic control in individuals with type 2 diabetes: a secondary analysis of a randomised clinical trial

AIMS/HYPOTHESIS

The aim was to investigate whether an intensive lifestyle intervention, with high volumes of exercise, improves beta cell function and to explore the role of low-grade inflammation and body weight.

METHODS

This was a randomised, assessor-blinded, controlled trial. Ninety-eight individuals with type 2 diabetes (duration <10 years), BMI of 25-40 kg/m², no use of insulin and taking fewer than three glucose-lowering medications were randomised (2:1) to either the standard care plus intensive lifestyle group or the standard care alone group. Standard care consisted of individual guidance on disease management, lifestyle advice and blinded regulation of medication following a pre-specified algorithm. The intensive lifestyle intervention consisted of aerobic exercise sessions that took place 5-6 times per week, combined with resistance exercise sessions 2-3 times per week, with a concomitant dietary intervention aiming for a BMI of 25 kg/m². In this secondary analysis beta cell function was assessed from the 2 h OGTT-derived disposition index, which is defined as the product of the Matsuda and the insulinogenic indices.

RESULTS

At baseline, individuals were 54.8 years (SD 8.9), 47% women, type 2 diabetes duration 5 years (IQR 3-8) and HbA_1c was 49.3 mmol/mol (SD 9.2); 6.7% (SD 0.8). The intensive lifestyle group showed 40% greater improvement in the disposition index compared with the standard care group (ratio of geometric mean change [RGM] 1.40 [95% CI 1.01, 1.94]) from baseline to 12 months' follow-up. Plasma concentration of IL-1 receptor antagonist (IL-1ra) decreased 30% more in the intensive lifestyle group compared with the standard care group (RGM 0.70 [95% CI 0.58, 0.85]). Statistical single mediation analysis estimated that the intervention effect on the change in IL-1ra and the change in body weight explained to a similar extent (59%) the variance in the intervention effect on the disposition index.

CONCLUSIONS/INTERPRETATION

Our findings show that incorporating an intensive lifestyle intervention, with high volumes of exercise, in individuals with type 2 diabetes has the potential to improve beta cell function, associated with a decrease in low-grade inflammation and/or body weight.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02417012 Graphical abstract.

Reduction in Circulating Advanced Glycation End Products by Mediterranean Diet Is Associated with Increased Likelihood of Type 2 Diabetes Remission in Patients with Coronary Heart Disease: From the Cordioprev Study

SCOPE

It is hypothesized that decreased advanced glycation end products (AGEs) levels could affect type 2 diabetes mellitus (T2DM) remission in newly diagnosed patients through the consumption of two healthy diets.

METHODS AND RESULTS

Patients from CORDIOPREV study, all with previous cardiovascular events, with T2DM at the beginning of the study are included. Patients are randomized to a Mediterranean or a low-fat diet for five years. No different diabetes remission rates are found among diets. Serum methylglioxal (MG) and carboximethyllysine (CML), levels dietary AGE, as well as gene expression of AGER1 and RAGE are measured. Serum MG decreases only after the consumption of the Mediterranean diet. Moreover, a COX regression analysis shows that each SD decrease in the MG, occurring after the Mediterranean diet, increases the probability of T2DM remission with HR:2.56(1.02-6.25) and p = 0.046 and each SD increase in disposition index at baseline increases the probability of remission with HR:1.94(1.32-2.87) and p = 0.001.

CONCLUSIONS

It is demonstrated that the reduction of serum AGEs levels and the modulation of its metabolism, occurring after the consumption of a Mediterranean diet, might be involved in the molecular mechanism underlying the T2DM remission of newly diagnosed patients with coronary heart disease.

Treatment of Obesity in Mitigating Metabolic Risk

Through diverse mechanisms, obesity contributes to worsened cardiometabolic health and increases rates of cardiovascular events. Effective treatment of obesity is necessary to reduce the associated burdens of diabetes mellitus, cardiovascular disease, and death. Despite increasing cardiovascular outcome data on obesity interventions, only a small fraction of the population with obesity are optimally treated. This is a primary impetus for this article in which we describe the typical weight loss, as well as the associated impact on both traditional and novel cardiovascular disease risk factors, provided by the 4 primary modalities for obtaining weight loss in obesity-dietary modification, increasing physical activity, pharmacotherapy, and surgery. We also attempt to highlight instances where changes in metabolic risk are relatively specific to particular interventions and appear at least somewhat independent of weight loss. Finally, we suggest important areas for further research to reduce and prevent adverse cardiovascular consequences due to obesity.

Metabolic endoscopy by duodenal mucosal resurfacing: expert review with critical appraisal of the current technique and results

INTRODUCTION

Duodenal mucosal resurfacing (DMR) is an endoscopic procedure for type 2 diabetes (T2D) consisting of circumferential hydrothermal ablation of the duodenal mucosa.

AREAS COVERED

A review was conducted on the reports available up to March-2020. On a total of 79 patients, DMR induced a significant mean HbA1c, FPG and HOMA-IR reduction at 6 months (0.9 ± 0.2%, 1.7 ± 0.5 mmol/L and 2.9 ± 1.1 mUI/L respectively - P < 0.001). DMR metabolic efficacy directly correlates with the length of the ablated mucosa (mean 3 months HbA1c reduction 1.2% vs 2.5% after short and long ablation respectively - P < 0.05), while it is independent of weight-loss. Severe AEs were registered in 3.7% of the cases.

EXPERT OPINION

DMR plays a promising role in metabolic impairment improvement inducing a morpho-functional duodenal alteration not necessarily depending on weight-loss. Technical-functional improvements of the device and appropriate training aimed at its correct use are needed to lower the rate of severe AEs and technical failure. The current role of DMR needs to be clarified, but it might be proposed for poorly controlled T2D in accurately selected patients. Evidence on DMR is still scanty and further research is mandatory to standardize the endoscopic technique and its indications.

Sera of Obese Type 2 Diabetic Patients Undergoing Metabolic Surgery Instead of Conventional Treatment Exert Beneficial Effects on Beta Cell Survival and Function: Results of a Randomized Clinical Study

BACKGROUND

Pancreatic beta cells are highly sensitive to oxidative and endoplasmic reticulum (ER) stress, commonly occurring in type 2 diabetes (T2D) and obesity.

OBJECTIVE

We aimed at investigating cellular responses of human beta cells exposed to sera from obese T2D patients treated differently, namely by conventional therapy or laparoscopic sleeve gastrectomy (LSG).

METHODS

Serum samples from obese T2D men randomized to conventional treatment or LSG were taken at baseline and 6 months later. After exposing 1.1B4 cells to study patients' sera, the following were assessed: cellular viability and proliferation (by MTT and xCELLigence assays), reactive oxygen species (ROS) production (with DCFH-DA), and expression of ER stress markers, oxidative- or autophagy-related proteins and insulin (by real-time PCR and Western blot).

RESULTS

At 6-month follow-up, patients undergoing LSG achieved an adequate glycemic control, whereas conventionally treated patients did not. As compared to 1.1B4 cells incubated with baseline sera (control), cells exposed to sera from LSG-treated participants exhibited (i) increased viability and proliferation (p < 0.05); (ii) diminished levels of ROS and p53 (p < 0.05); (iii) enhanced protein expression of autophagy-related SIRT1 and p62/SQSTM1 (p < 0.05); (iv) significantly decreased transcript levels of ER stress markers (p < 0.05); and (v) augmented insulin expression (p < 0.05). Conversely, the 6-month conventional therapy appeared not to impact on circulating redox status. Moreover, 1.1B4 cells exposed to sera from conventionally treated patients experienced mild ER stress.

CONCLUSION

Circulating factors in patients with improved diabetes after metabolic surgery exerted favorable effects on beta cell function and survival.

Expansion and Impaired Mitochondrial Efficiency of Deep Subcutaneous Adipose Tissue in Recent-Onset Type 2 Diabetes

CONTEXT/OBJECTIVE

Impaired adipose tissue (AT) function might induce recent-onset type 2 diabetes (T2D). Understanding AT energy metabolism could yield novel targets for the treatment of T2D.

DESIGN/PATIENTS

Male patients with recently-diagnosed T2D and healthy male controls (CON) of similar abdominal subcutaneous AT (SAT)-thickness, fat mass, and age (n = 14 each), underwent hyperinsulinemic-euglycemic clamps with [6,6-2H2]glucose and indirect calorimetry. We assessed mitochondrial efficiency (coupling: state 3/4o; proton leak: state 4o/u) via high-resolution respirometry in superficial (SSAT) and deep (DSAT) SAT-biopsies, hepatocellular lipids (HCL) and fat mass by proton-magnetic-resonance-spectroscopy and -imaging.

RESULTS

T2D patients (known diabetes duration: 2.5 [0.1; 5.0] years) had 43%, 44%, and 63% lower muscle insulin sensitivity (IS), metabolic flexibility (P < 0.01) and AT IS (P < 0.05), 73% and 31% higher HCL (P < 0.05), and DSAT-thickness (P < 0.001), but similar hepatic IS compared with CON. Mitochondrial efficiency was ~22% lower in SSAT and DSAT of T2D patients (P < 0.001) and ~8% lower in SSAT vs DSAT (P < 0.05). In both fat depots, mitochondrial coupling correlated positively with muscle IS and metabolic flexibility (r ≥ 0.40; P < 0.05), proton leak correlated positively (r ≥ 0.51; P < 0.01) and oxidative capacity negatively (r ≤ -0.47; P < 0.05) with fasting free fatty acids (FFA). Metabolic flexibility correlated positively with SAT-oxidative capacity (r ≥ 0.48; P < 0.05) and negatively with DSAT-thickness (r = -0.48; P < 0.05). DSAT-thickness correlated negatively with mitochondrial coupling in both depots (r ≤ -0.50; P < 0.01) and muscle IS (r = -0.59; P < 0.01), positively with FFA during clamp (r = 0.63; P < 0.001) and HCL (r = 0.49; P < 0.01).

CONCLUSIONS

Impaired mitochondrial function, insulin resistance, and DSAT expansion are AT abnormalities in recent-onset T2D that might promote whole-body insulin resistance and increased substrate flux to the liver.

Bariatric Surgery and Type 1 Diabetes: Unanswered Questions

In recent decades there has been an alarming increase in the prevalence of obesity in patients with type 1 diabetes leading to the development of insulin resistance and cardiometabolic complications, with mechanisms poorly clarified. While bariatric surgery has long been considered an effective treatment option for patients with type 2 diabetes, the evidence regarding its benefits on weight loss and the prevention of complications in T1DM patients is scarce, with controversial outcomes. Bariatric surgery has been associated with a significant reduction in daily insulin requirement, along with a considerable reduction in body mass index, results which were sustained in the long term. Furthermore, studies suggest that bariatric surgery in type 1 diabetes results in the improvement of comorbidities related to obesity including hypertension and dyslipidemia. However, regarding glycemic control, the reduction of mean glycosylated hemoglobin was modest or statistically insignificant in most studies. The reasons for these results are yet to be elucidated; possible explanations include preservation of beta cell mass and increased residual function post-surgery, improvement in insulin action, altered GLP-1 function, timing of surgery, and association with residual islet cell mass. A number of concerns regarding safety issues have arisen due to the reporting of peri-operative and post-operative adverse events. The most significant complications are metabolic and include diabetic ketoacidosis, severe hypoglycemia and glucose fluctuations. Further prospective clinical studies are required to provide evidence for the effect of bariatric surgery on T1DM patients. The results may offer a better knowledge for the selection of people living with diabetes who will benefit more from a metabolic surgery.

Differences in Calcium Metabolism and Thyroid Physiology After Sleeve Gastrectomy and Roux-En-Y Gastric Bypass

INTRODUCTION

Bariatric surgery may modulate the hormones and elements which maintain thyroid and calcium homeostasis. These adaptations in hormonal and elemental aspects have previously been determined via some studies with variations in their findings. Thyroid volume and 24-h urinary calcium are two parameters which have not been investigated regarding whether they change during the bariatric postsurgical period. This study planned to examine the changes in calcium metabolism and thyroid gland functioning after sleeve gastrectomy (SG) and Roux-en-Y gastric bypass (RYGB).

MATERIALS AND METHODS

Seventy-three morbidly obese patients with planned bariatric surgery were enrolled in the study. Before and 12 months after the operation, parathormone (PTH), 25-OH-vitamin D3(25vitD3), TSH, free triiodothyronine (fT3), free thyroxine (fT4), calcium (Ca), 24-h urinary Ca and ultrasonography-guided thyroid volume were measured.

RESULTS

In the beginning, 73 patients were examined and 12 months after surgery out of 25 patients continuing follow-up, 20 (80%) had undergone sleeve gastrectomy (SG) while five (20%) had undergone Roux-en-Y gastric bypass (RYGB). Accompanied by significant BMI decrease, 24-h urinary Ca and thyroid volume did not significantly increase in RYGB, SG, and the whole group after 12 months. The SG group showed a significant drop in TSH (p 0.03) level, while the RYGB group showed significant decreases in fT4 (p 0.00) and fT3 (p 0.00); and significant fT3 decrease (p 0.01) was recorded for the whole group.

CONCLUSION

Bariatric surgery may modify Ca homeostasis and thyroid gland functional status. We documented that these were not statistically significant increases in 24-h urinary Ca level and thyroid volume after 1 year. Further studies are needed to understand the issue, enrolling more patients who underwent the same bariatric procedure and after accounting for the inhibition of supplementary vitamin and mineral effects.

Endoscopic duodenal mucosal resurfacing improves glycaemic and hepatic indices in type 2 diabetes: 6-month multicentre results

Insulin resistance is a core pathophysiological defect underscoring type 2 diabetes mellitus (T2DM) and non-alcoholic fatty liver disease (NAFLD). Both conditions improve with duodenal exclusion surgery. Duodenal mucosal resurfacing (DMR) is an endoscopic intervention developed to treat metabolic disease which has been shown to improve glycaemia in patients with poorly controlled T2DM. Herein, we aimed to further analyse the effects of DMR on hepatic and metabolic parameters in this patient cohort.

METHODS

Eighty-five patients with T2DM who received endoscopic DMR treatment were enrolled from 5 centres and followed up for 6 months. We assessed safety in all patients. Efficacy was evaluated in patients who received at least 9 cm of duodenal ablation (n = 67). Endpoints included HbA1c, fasting plasma glucose, weight and aminotransferase levels. Metabolomic analysis was conducted in a subgroup (n = 14). Data were analysed using paired t test or ANOVA for repeated measures with Bonferroni correction and correction for initial weight loss if applicable.

RESULTS

The DMR procedure was completed with no intraprocedural complications in the entire cohort. HbA1c was lower 6 months after DMR than at baseline (7.9 ± 0.2% vs. 9.0 ± 0.2% [mean ± SE], p ≪0.001). Fasting plasma glucose was also significantly lower 6 months after DMR compared to baseline (161 ± 7 mg/dl vs. 189 ± 6 mg/dl, p = 0.005). Body weight decreased slightly. At 6 months, alanine aminotransferase had decreased from 41 ± 3 IU/L to 29 ± 2 IU/L (p ≪0.001) and aspartate aminotransferase had decreased from 30 ± 2 IU/L to 23 ± 1 IU/L (p ≪0.001). Metabolomic analysis demonstrated that DMR had key lipid-lowering, insulin-sensitizing and anti-inflammatory effects, as well as increasing antioxidant capacity. Mean FIB-4 was also markedly decreased.

CONCLUSION

Hydrothermal ablation of the duodenum by DMR elicits a beneficial metabolic response in patients with T2DM. DMR also improves hepatic indices, potentially through an insulin-sensitizing mechanism. These encouraging data deserve further evaluation in randomized controlled trials.

LAY SUMMARY

Hydrothermal duodenal mucosal resurfacing (DMR) is an endoscopic technique designed to treat metabolic disease through ablation of the duodenal mucosa. DMR is a safe procedure which improves glycaemia and hepatic indices in patients with type 2 diabetes mellitus. DMR is an insulin-sensitizing intervention which can be complementary to lifestyle intervention approaches and pharmacological treatments aimed at preserving the pancreas and liver from failure. DMR is a potential therapeutic solution for patients with type 2 diabetes and fatty liver disease.

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.

Duodenal mucosal resurfacing: proof-of-concept, procedural development, and initial implementation in the clinical setting

BACKGROUND AND AIMS

We aimed to develop duodenal mucosal resurfacing (DMR), a minimally invasive upper endoscopic hydrothermal ablation procedure, to treat insulin-resistant metabolic diseases.

METHODS

We completed a sham-controlled, rodent proof-of-concept study and longitudinal safety study in pigs to demonstrate feasibility to test DMR in humans. Subsequently, the DMR procedure was implemented in an open-label first-in-human (FIH) study of safety and efficacy in patients with type 2 diabetes (T2D).

RESULTS

In rats, duodenal abrasion reduced hyperglycemia by 59 mg/dL on average, compared with no change from baseline in the sham treatment arm (P < .05). In pigs, the balloon catheter successfully and safely delivered hydrothermal ablation to the duodenal mucosa and superficial submucosa. Complete mucosal healing was demonstrated by week 6. In the FIH study, hydrothermal ablation was successfully administered with no evidence of perforation, pancreatitis, or hemorrhage. Duodenal biopsy specimens obtained 3 months postprocedure demonstrated full mucosal regrowth. No inflammation was observed, and there was minimal-to-mild collagen banding deposition observed in a proportion of ablation site biopsy specimens with no evidence of fibrotic scarring. Glycemic and hepatic measures improved through 6 months of follow-up.

CONCLUSIONS

DMR shows potential as an endoscopic intervention that improves glycemic and hepatic parameters in patients with T2D. Further mechanistic and clinical studies are underway to further explore DMR as a treatment for metabolic disease.

Mechanisms Underlying Type 2 Diabetes Remission After Metabolic Surgery

Type 2 diabetes prevalence is increasing dramatically worldwide. Metabolic surgery is the most effective treatment for selected patients with diabetes and/or obesity. When compared to intensive medical therapy and lifestyle intervention, metabolic surgery has shown superiority in achieving glycemic improvement, reducing number of medications and cardiovascular risk factors, which translates in long-term benefits on cardiovascular morbidity and mortality. The mechanisms underlying diabetes improvement after metabolic surgery have not yet been clearly understood but englobe a complex interaction among improvements in beta cell function and insulin secretion, insulin sensitivity, intestinal gluconeogenesis, changes in glucose utilization, and absorption by the gut and changes in the secretory pattern and morphology of adipose tissue. These are achieved through different mediators which include an enhancement in gut hormones release, especially, glucagon-like peptide 1, changes in bile acids circulation, gut microbiome, and glucose transporters expression. Therefore, this review aims to provide a comprehensive appraisal of what is known so far to better understand the mechanisms through which metabolic surgery improves glycemic control facilitating future research in the field.

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.

Endoscopic Duodenal Mucosal Resurfacing for the Treatment of Type 2 Diabetes

Type 2 diabetes is a pandemic disease with an incidence that has risen steadily over recent decades. Experimental evidence in animals has demonstrated that intestinal bypass surgery of the upper small intestine, particularly the duodenum, has an important role in glucose homoeostasis. Furthermore, Roux-en-Y bypass performed as bariatric surgery has shown to correct hyperglycaemia from the first postoperative days in obese diabetic patients. Therefore, on the basis of these considerations, duodenal mucosal resurfacing was studied in type 2 diabetes patients as a minimally invasive procedure that could offer an alternative treatment for these patients. Further studies, and particularly large controlled trials, are needed to determine the place of this procedure in the treatment of type 2 diabetes as well as other metabolic diseases such as non-alcoholic fatty liver disease/non-alcoholic steatohepatitis.

Intestinal peptide changes after bariatric and minimally invasive surgery: Relation to diabetes remission

Bariatric surgery is very effective in achieving and maintaining weight loss but it is also associated with improvement of obesity metabolic complications, primarily type 2 diabetes (T2D). Remission of T2D or at least a net improvement of glycemic control persists for at least 5 years. The bypass of duodenum and of the first portion of the jejunum up to the Treitz ligament as in Roux-en-Y Gastric Bypass (RYGB), or the bypass of the duodenum, the entire jejunum and the first tract of the ileum, such as in Bilio-Pancreatic Diversion (BPD), achieve different results on insulin sensitivity. Insulin resistance is the major driver of T2D manifesting long before insulin secretion failure. In fact, T2D development can be prevented by treatment with insulin sensitizing agents. Interestingly, RYGB improves hepatic insulin sensitivity while BPD ameliorates whole-body insulin sensitivity. Two major theories have been advocated to explain the early remission of T2D following RYGB or BPD before a meaningful weight loss takes place, the foregut and the hindgut hypotheses. The former holds that the bypass of the proximal intestine, i.e. duodenum and jejunum, prevents the secretion of signals - including nervous transmitters and hormones - promoting insulin resistance, the latter instead states that the delivery of nutrients directly into the ileum stimulates the secretion of hormones improving glucose disposal. The most studied candidate is Glucagon Like Peptide 1 (GLP1). However, while there is unambiguous evidence that GLP-1 stimulates insulin secretion, its direct action in lowering insulin resistance, independently of the effect on weight loss secondary to its satiety action, is utterly controversial. In this review we examine the effects on T2D and gastrointestinal peptide secretion produced by different types of metabolic surgery and by minimally invasive endoscopic surgery, whose utilization for the treatment of obesity and T2D is gaining wider interest and acceptance.

Diabetes recurrence after metabolic surgeries correlates with re-impaired insulin sensitivity rather than beta-cell function

AIM

To investigate factors causing diabetes recurrence after sleeve gastrectomy (SG) and duodenal-jejunal bypass (DJB).

METHODS

SG and DJB were performed on rats with diabetes induced by high-fat diet (HFD) and streptozotocin (STZ). HFD was used to induce diabetes recurrence at 4 wk postoperatively. Body weight, oral glucose tolerance test, homeostatic model assessment of insulin resistance (HOMA-IR), insulin signaling [IR, insulin receptor substrate (IRS)1, IRS2, phosphatidylinositol 3-kinase and AKT in liver and skeletal muscle], oral glucose stimulated insulin secretion, beta-cell morphology (mass, apoptosis and insulin secretion), glucagon-like peptide (GLP)-1, PYY and ghrelin were compared among SG rats with common low-fat diet (SG-LFD), SG with HFD (SG-HFD), DJB rats with LFD (DJB-LFD), DJB with HFD (DJB-HFD) and sham-operation with LFD (Sham) at targeted postoperative times.

RESULTS

SG and DJB resulted in significant improvement in glucose tolerance, lower HOMA-IR, up-regulated hepatic and muscular insulin signaling, higher levels of oral glucose-stimulated insulin secretion, bigger beta-cell mass, higher immunofluorescence intensity of insulin, fewer transferase-mediated dUTP-biotin 3’ nick end-labeling (TUNEL)-positive beta cells and higher postprandial GLP-1 and PYY levels than in the Sham group. The improvement in glucose tolerance was reversed at 12 wk postoperatively. Compared with the SG-LFD and DJB-LFD groups, the SG-HFD and DJB-HFD groups showed higher HOMA-IR, down-regulated hepatic and muscular insulin signaling, and more TUNEL-positive beta cells. No significant difference was detected between HFD and LFD groups for body weight, glucose-stimulated insulin secretion, beta-cell mass, immunofluorescence intensity of insulin, and postprandial GLP-1 and PYY levels. Fasting serum ghrelin decreased in SG groups, and there was no difference between HFD-SG and LFD-SG groups.

CONCLUSION

HFD reverses the improvement in glucose homeostasis after SG and DJB. Diabetes recurrence may correlate with re-impaired insulin sensitivity, but not with alterations of beta-cell function and body weight.

Effects of weight loss on adipose visceral and subcutaneous tissue in overweight adults

BACKGROUND & AIMS

Weight loss is an important strategy for mitigating the complications of obesity. However, weight reduction does not provide detailed information on relative changes in bodily behaviors and in abdominal fat deposits (adipose visceral tissue (AVT) and adipose subcutaneous tissue (AST)). The aim of this study was to evaluate the effect of weight loss based on calorie restriction on AVT and AST in overweight individuals (1); to verify the metabolic benefits resulting from AVT reduction (2); and to the analyze the influence of covariates in AVT and AST reduction (3).

METHODS

Clinical intervention study involving overweight adult patients, seen at a public hospital in the Northeast of Brazil, who underwent three months of calorie restriction. AVT and AST were quantified using computed tomography at the baseline and at the end of a follow up.

RESULTS

51 patients were evaluated (50.2 ± 11.3 years old), for whom it was verified that a 5.8(±6.2)% weight reduction in the men resulted in a 11.2(±7.9)% reduction in AVT and 6.8(±11.2)% in AST. Among the women, a 4.1(±2.5)% reduction in initial weight resulted in a 11.1(±8.8)% decrease in AVT and 5.6(±7.4)% in AST. Simple linear regression showed that a reduction in AVT caused a 54.9% reduction in triglyceride concentrations in the men and a 12.2% reduction in cholesterol and 31.4% in triglyceride levels in women. Multiple regression identified different factors that influenced the reduction in visceral and subcutaneous fat. The predictive models explained 42.9% and 54.8% of the AVT reduction in the females and males, respectively; and 39.9% and 86.7% of the AST reduction in the females and males, respectively.

CONCLUSIONS

A modest 5% weight loss caused substantial AVT and AST mobilization, with potential benefits to cardiometabolic profile.

Hydrothermal Duodenal Mucosal Resurfacing: Role in the Treatment of Metabolic Disease

The duodenum has become recognized as a metabolic signaling center that is involved in regulating insulin action and, therefore, insulin resistance states such as type 2 diabetes. Bariatric surgery and other manipulations of the upper intestine, in particular the duodenum, have shown that limiting nutrient exposure or contact in this key region exerts powerful metabolic effects. Early human clinical trial data suggest that endoscopic hydrothermal duodenal mucosal resurfacing is well tolerated in human subjects and has an acceptable safety profile. This article describes the rationale for this endoscopic approach and its early human use, including safety, tolerability, and early efficacy.

Microvascular Outcomes after Metabolic Surgery (MOMS) in patients with type 2 diabetes mellitus and class I obesity: rationale and design for a randomised controlled trial

INTRODUCTION

There are several randomised controlled trials (RCTs) that have already shown that metabolic/bariatric surgery achieves short-term and long-term glycaemic control while there are no level 1A of evidence data regarding the effects of surgery on the microvascular complications of type 2 diabetes mellitus (T2DM).

PURPOSE

The aim of this trial is to investigate the long-term efficacy and safety of the Roux-en-Y gastric bypass (RYGB) plus the best medical treatment (BMT) versus the BMT alone to improve microvascular outcomes in patients with T2DM with a body mass index (BMI) of 30-34.9 kg/m².

METHODS AND ANALYSIS

This study design includes a unicentric randomised unblinded controlled trial. 100 patients (BMI from 30 to 34.9 kg/m²) will be randomly allocated to receive either RYGB plus BMT or BMT alone. The primary outcome is the change in the urine albumin-to-creatinine ratio (uACR) captured as the proportion of patients who achieved nephropathy remission (uACR<30 mg/g of albumin/mg of creatinine) in an isolated urine sample over 12, 24 and 60 months.

ETHICS AND DISSEMINATION

The study was approved by the local Institutional Review Board. This study represents the first RCT comparing RYGB plus BMT versus BMT alone for patients with T2DM with a BMI below 35 kg/m².

TRIAL REGISTRATION NUMBER

NCT01821508; Pre-results.

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.

Endoscopic Duodenal Mucosal Resurfacing for the Treatment of Type 2 Diabetes: 6-Month Interim Analysis From the First-in-Human Proof-of-Concept Study

OBJECTIVE

To assess procedural safety and glycemic indices at 6 months in a first-in-human study of duodenal mucosal resurfacing (DMR), a novel, minimally invasive, upper endoscopic procedure involving hydrothermal ablation of the duodenal mucosa, in patients with type 2 diabetes and HbA_1c ≥7.5% (58 mmol/mol) on one or more oral antidiabetic agents.

RESEARCH DESIGN AND METHODS

Using novel balloon catheters, DMR was conducted on varying lengths of duodenum in anesthetized patients at a single medical center.

RESULTS

A total of 39 patients with type 2 diabetes (screening HbA_1c 9.5% [80 mmol/mol]; BMI 31 kg/m²) were treated and included in the interim efficacy analysis: 28 had a long duodenal segment ablated (LS; ∼9.3 cm treated) and 11 had a short segment ablated (SS; ∼3.4 cm treated). Overall, DMR was well tolerated with minimal gastrointestinal symptoms postprocedure. Three patients experienced duodenal stenosis treated successfully by balloon dilation. HbA_1c was reduced by 1.2% at 6 months in the full cohort (P < 0.001). More potent glycemic effects were observed among the LS cohort, who experienced a 2.5% reduction in mean HbA_1c at 3 months postprocedure vs. 1.2% in the SS group (P < 0.05) and a 1.4% reduction at 6 months vs. 0.7% in the SS group (P = 0.3). This occurred despite net medication reductions in the LS cohort between 0 and 6 months. Among LS patients with a screening HbA_1c of 7.5-10% (58-86 mmol/mol) and on stable antidiabetic medications postprocedure, HbA_1c was reduced by 1.8% at 6 months (P < 0.01).

CONCLUSIONS

Single-procedure DMR elicits a clinically significant improvement in hyperglycemia in patients with type 2 diabetes in the short-term, with acceptable safety and tolerability. Long-term safety, efficacy, and durability and possible mechanisms of action require further investigation.