Time Course of Normalization of Functional β-Cell Capacity in the Diabetes Remission Clinical Trial After Weight Loss in Type 2 Diabetes

Improvement of β-Cell Function After Switching From DPP-4 Inhibitors to Oral Semaglutide: SWITCH-SEMA2 Post Hoc Analysis

CONTEXT

Whether continuation of dipeptidyl peptidase-4 inhibitors (DPP-4is) or switching to oral semaglutide is more beneficial for β-cell function is unclear.

OBJECTIVE

To assess the efficacy of switching from DPP-4is to oral semaglutide for β-cell function compared with DPP-4i continuation.

METHODS

Post hoc analysis of SWITCH-SEMA 2, a multicenter prospective randomized controlled trial on the switch to oral semaglutide vs DPP-4i continuation without dose adjustment for 24 weeks in subjects with type 2 diabetes treated with DPP-4is, was conducted. Changes in markers for glucose metabolism, including homeostatic model assessment (HOMA2) scores and disposition index (DI), were compared between the groups.

RESULTS

A total of 146 subjects (semaglutide group, 69; DPP-4i group, 77) were analyzed. In the semaglutide group, glycemic control, liver enzyme deviations, and lipid profiles improved after 24 weeks. Regarding indices for β-cell function, changes in HOMA2-β as well as DI, reflecting the ability of β-cells to compensate for insulin resistance, were significantly higher in the semaglutide group compared with the DPP-4i group (mean change, +10.4 vs +0.6 in HOMA2-β [P = .001] and +0.09 vs 0.0 in DI [P < .001]). Improvement in DI in the semaglutide group was correlated significantly to changes in body mass index (BMI), HbA1c, and fatty liver index reflecting liver steatosis. Multiple linear regression analysis revealed that dose of semaglutide (≥ 7 mg/day), reduction in fatty liver index, and metformin nonuse were independently associated with improvement of DI.

CONCLUSION

Switching to oral semaglutide ameliorated β-cell function compared with DPP-4is, presumably via tissue-to-tissue crosstalk between liver and β-cells.

The Twin Cycle Hypothesis of type 2 diabetes aetiology: From concept to national NHS programme

The development of magnetic resonance methods for quantifying intra-organ metabolites has permitted advances in the understanding of fasting and post-prandial carbohydrate and lipid handling in people with and without type 2 diabetes. Insulin resistance in the liver was shown to be related to excess intra-organ fat and was able to be returned to normal by weight loss. The practical effect of having muscle insulin sensitivity in the lower part of the wide normal range resulted in the obligatory shunting of carbohydrates via de novo lipogenesis into saturated fat. These observations provided the basis for the Twin Cycle Hypothesis of the aetiology of type 2 diabetes. Subsequent studies on people with type 2 diabetes confirmed the postulated pathophysiological abnormalities and demonstrated their reversibility by dietary weight loss of 10-15 kg. Overall, the fundamental understanding of the mechanisms causing type 2 diabetes has bridged physiological and clinical perspectives. Large population-based randomised controlled trials confirmed the practical clinical application of the method of achieving substantial weight loss, and an NHS programme is now in place offering potential remission to people within 6 years of diagnosis.

Revisiting the Pattern of Loss of β-Cell Function in Preclinical Type 1 Diabetes

Type 1 diabetes (T1D) results from β-cell destruction due to autoimmunity. It has been proposed that β-cell loss is relatively quiescent in the early years after seroconversion to islet antibody positivity (stage 1), with accelerated β-cell loss only developing around 6-18 months prior to clinical diagnosis. This construct implies that immunointervention in this early stage will be of little benefit, since there is little disease activity to modulate. Here, we argue that the apparent lack of progression in early-stage disease may be an artifact of the modality of assessment used. When substantial β-cell function remains, the standard assessment, the oral glucose tolerance test, represents a submaximal stimulus and underestimates the residual function. In contrast, around the time of diagnosis, glucotoxicity exerts a deleterious effect on insulin secretion, giving the impression of disease acceleration. Once glucotoxicity is relieved by insulin therapy, β-cell function partially recovers (the honeymoon effect). However, evidence from recent trials suggests that glucose control has little effect on the underlying disease process. We therefore hypothesize that the autoimmune destruction of β-cells actually progresses at a more or less constant rate through all phases of T1D and that early-stage immunointervention will be both beneficial and desirable.

ARTICLE HIGHLIGHTS

Advances and counterpoints in type 2 diabetes. What is ready for translation into real-world practice, ahead of the guidelines

This review seeks to address major gaps and delays between our rapidly evolving body of knowledge on type 2 diabetes and its translation into real-world practice. Through updated and improved best practices informed by recent evidence and described herein, we stand to better attain A1c targets, help preserve beta cell integrity and moderate glycemic variability, minimize treatment-emergent hypoglycemia, circumvent prescribing to "treatment failure," and prevent long-term complications. The first topic addressed in this review concerns updates in the 2023 and 2024 diabetes treatment guidelines for which further elaboration can help facilitate integration into routine care. The second concerns advances in diabetes research that have not yet found their way into guidelines, though they are endorsed by strong evidence and are ready for real-world use in appropriate patients. The final theme addresses lingering misconceptions about the underpinnings of type 2 diabetes-fundamental fallacies that continue to be asserted in the textbooks and continuing medical education upon which physicians build their approaches. A corrected and up-to-date understanding of the disease state is essential for practitioners to both conceptually and translationally manage initial onset through late-stage type 2 diabetes.

Understanding the cause of type 2 diabetes

Type 2 diabetes has long been thought to have heterogenous causes, even though epidemiological studies uniformly show a tight relationship with overnutrition. The twin cycle hypothesis postulated that interaction of self-reinforcing cycles of fat accumulation inside the liver and pancreas, driven by modest but chronic positive calorie balance, could explain the development of type 2 diabetes. This hypothesis predicted that substantial weight loss would bring about a return to the non-diabetic state, permitting observation of the pathophysiology determining the transition. These changes were postulated to reflect the basic mechanisms of causation in reverse. A series of studies over the past 15 years has elucidated these underlying mechanisms. Together with other research, the interaction of environmental and genetic factors has been clarified. This knowledge has led to successful implementation of a national programme for remission of type 2 diabetes. This Review discusses the paucity of evidence for heterogeneity in causes of type 2 diabetes and summarises the in vivo pathophysiological changes, which cause this disease of overnutrition. Type 2 diabetes has a homogenous cause expressed in genetically heterogenous individuals.

Cardioprotective benefits of metabolic surgery and GLP-1 receptor agonist-based therapies

Individuals with excessive adipose tissue and type 2 diabetes mellitus (T2DM) face a heightened risk of cardiovascular morbidity and mortality. Metabolic surgery is an effective therapy for people with severe obesity to achieve significant weight loss. Additionally, metabolic surgery improves blood glucose levels and can lead to T2DM remission, reducing major adverse cardiovascular outcomes (MACE). Glucagon-like peptide 1 (GLP-1) receptor agonists (GLP-1RAs) are a class of medication that effectively reduce body weight and MACE in patients with T2DM. This review explores the potential mechanisms underlying the cardioprotective benefits of metabolic surgery and GLP-1RA-based therapies and discusses recent evidence and emerging therapies in this dynamic area of research.

Diabetes remission and nonalcoholic fatty pancreas disease

This editorial focuses on the relationship between nonalcoholic fatty pancreas disease (NAFPD) and the development and remission of type 2 diabetes (T2D). NAFPD is characterized by intrapancreatic fatty deposition associated with obesity and not associated with alcohol abuse, viral infections, and other factors. Ectopic fat deposition in the pancreas is associated with the development of T2D, and the underlying mechanism is lipotoxic β-cell dysfunction. However, the results on the relationship between intrapancreatic fat deposition (IPFD) and β-cell function are conflicting. Regardless of the therapeutic approach, weight loss improves IPFD, glycemia, and β-cell function. Pancreatic imaging is valuable for clinically monitoring and evaluating the management of T2D.

5-year follow-up of the randomised Diabetes Remission Clinical Trial (DiRECT) of continued support for weight loss maintenance in the UK: an extension study

BACKGROUND

In DiRECT, a randomised controlled effectiveness trial, weight management intervention after 2 years resulted in mean weight loss of 7·6 kg, with 36% of participants in remission of type 2 diabetes. Of 36 in the intervention group who maintained over 10 kg weight loss at 2 years, 29 (81%) were in remission. Continued low-intensity dietary support was then offered up to 5 years from baseline to intervention participants, aiming to maintain weight loss and gain clinical benefits. This extension study was designed to provide observed outcomes at 5 years.

METHODS

The DiRECT trial took place in primary care practices in the UK. Participants were individuals aged 20-65 years who had less than 6 years' duration of type 2 diabetes, a BMI greater than 27 kg/m2, and were not on insulin. The intervention consisted of withdrawal of antidiabetic and antihypertensive drugs, total diet replacement (825-853 kcal per day formula diet for 12-20 weeks), stepped food reintroduction (2-8 weeks), and then structured support for weight-loss maintenance. After sharing the 2-year results with all participants, UK National Health Service data were collected annually until year 5 from remaining intervention participants who received low-intensity dietary support, intervention withdrawals, and the original randomly allocated groups. The primary outcome was remission of type 2 diabetes; having established in the DiRECT trial that sustained weight loss was the dominant driver of remission, this was assumed for the Extension study. The trial is registered with the ISRCTN registry, number 03267836.

FINDINGS

Between July 25, 2014, and Aug 5, 2016, 149 participants were randomly assigned to the intervention group and 149 were assigned to the control group in the original DiRECT study. After 2 years, all intervention participants still in the trial (101 [68%] of 149) were approached to receive low-intensity support for a further 3 years. 95 (94%) of 101 were able to continue and consented and were allocated to the DiRECT extension group. 54 participants were allocated to the non-extension group, where intervention was withdrawn. At 5 years, DiRECT extension participants (n=85) lost an average of 6·1 kg, with 11 (13%) of 85 in remission. Compared with the non-extension group, DiRECT extension participants had more visits with HbA1c <48 mmol/mol (<6·5%; 36% vs 17%, p=0·0004), without glucose-lowering medication (62% vs 30%, p<0·0001), and in remission (34% vs 12%, p<0·0001). Original control participants (n=149) had mean weight loss 4·6 kg (n=82), and 5 (5%) of 93 were in remission. Compared with control participants, original intervention participants had more visits with weight more than 5% below baseline (61% vs 29%, p<0·0001), HbA1c below 48 mmol/mol (29% vs 15%, p=0·0002), without antidiabetic medication (51% vs 16%, p<0·0001), and in remission (27% vs 4%, p<0·0001). Of those in remission at year 2, 26% remained in remission at 5 years. Serious adverse events in the original intervention group (4·8 events per 100 patient-years) were under half those in the control group (10·2 per 100 patient-years, p=0·0080).

INTERPRETATION

The extended DiRECT intervention was associated with greater aggregated and absolute weight loss, and suggested improved health status over 5 years.

FUNDING

Diabetes UK.

Modelling remission from overweight type 2 diabetes reveals how altering advice may counter relapse

The development or remission of diet-induced overweight type 2 diabetes involves many biological changes which occur over very different timescales. Remission, defined by HbA1c<6.5%, or fasting plasma glucose concentration G<126 mg/dl, may be achieved rapidly by following weight loss guidelines. However, remission is often short-term, followed by relapse. Mathematical modelling provides a way of investigating a typical situation, in which patients are advised to lose weight and then maintain fat mass, a slow variable. Remission followed by relapse, in a modelling sense, is equivalent to changing from a remission trajectory with steady state G<126 mg/dl, to a relapse trajectory with steady state G≥126 mg/dl. Modelling predicts that a trajectory which maintains weight will be a relapse trajectory, if the fat mass chosen is too high, the threshold being dependent on the lipid to carbohydrate ratio of the diet. Modelling takes into account the effects of hepatic and pancreatic lipid on hepatic insulin sensitivity and β-cell function, respectively. This study leads to the suggestion that type 2 diabetes remission guidelines be given in terms of model parameters, not variables; that is, the patient should adhere to a given nutrition and exercise plan, rather than achieve a certain subset of variable values. The model predicts that calorie restriction, not weight loss, initiates remission from type 2 diabetes; and that advice of the form 'adhere to the diet and exercise plan' rather than 'achieve a certain weight loss' may help counter relapse.

Treat Obesity to Treat Type 2 Diabetes Mellitus

Obesity, a multifactorial, relapsing chronic disease, serves as a gateway to a spectrum of metabolic, cardiovascular, mechanical and mental health problems. Over the last few decades, the global prevalence of obesity has surged nearly threefold, mirroring the escalating rates of type 2 diabetes mellitus (T2DM). This parallel trajectory strongly suggests a cause-and-effect relationship between obesity and T2DM. Extensive research indicates that even modest weight gain elevates the risk of T2DM, favoring the notion of obesity being a root cause. This perspective finds robust support in numerous studies demonstrating the preventive effects of obesity management on the onset of T2DM. Beyond prevention, obesity management has been shown to enhance remission in individuals with T2DM and to decrease microvascular complications, cardiovascular risk factors, renal failure and heart failure. This evidence underpins the urgent need for global initiatives aimed at addressing obesity management as a key strategy in the prevention and management of T2DM and its complications.

Glycaemic control efficacy of switching from dipeptidyl peptidase-4 inhibitors to oral semaglutide in subjects with type 2 diabetes: A multicentre, prospective, randomized, open-label, parallel-group comparison study (SWITCH-SEMA 2 study)

AIM

To assess whether oral semaglutide provides better glycaemic control, compared with dipeptidyl peptidase-4 inhibitor (DPP-4i) continuation, in people with type 2 diabetes.

MATERIALS AND METHODS

In this multicentre, open-label, prospective, randomized, parallel-group comparison study, participants receiving DPP-4is were either switched to oral semaglutide (3-14 mg/day) or continued on DPP-4is. The primary endpoint was the change in glycated haemoglobin (HbA1c) over 24 weeks. Secondary endpoints included changes in metabolic parameters and biomarkers, along with the occurrence of adverse events. Factors associated with HbA1c improvement were also explored.

RESULTS

In total, 174 eligible participants were enrolled; 17 dropped out of the study. Consequently, 82 participants in the DPP-4i group and 75 participants in the semaglutide group completed the study and were included in the analysis. Improvement in HbA1c at week 24 was significantly greater when switching to semaglutide compared with DPP-4i continuation [-0.65 (95% confidence interval: -0.79, -0.51) vs. +0.05 (95% confidence interval: -0.07, 0.16) (p < .001)]. Body weight, lipid profiles and liver enzymes were significantly improved in the semaglutide group than in the DPP-4i continuation group. Multiple linear regression analysis revealed that baseline HbA1c and homeostasis model assessment 2-R were independently associated with HbA1c improvement after switching to semaglutide. Seven participants in the semaglutide group discontinued medication because of gastrointestinal symptoms.

CONCLUSIONS

Although the potential for gastrointestinal symptoms should be carefully considered, switching from DPP-4is to oral semaglutide may be beneficial for glycaemic control and metabolic abnormalities in people with higher HbA1c and insulin resistance.

Prevention of cardiorenal complications in people with type 2 diabetes and obesity

Traditional approaches to prevention of the complications of type 2 diabetes (T2D) and obesity have focused on reduction of blood glucose and body weight. The development of new classes of medications, together with evidence from dietary weight loss and bariatric surgery trials, provides new options for prevention of heart failure, chronic kidney disease, myocardial infarction, stroke, metabolic liver disease, cancer, T2D, and neurodegenerative disorders. Here I review evidence for use of lifestyle modification, SGLT-2 inhibitors, GLP-1 receptor agonists, selective mineralocorticoid receptor antagonists, and bariatric surgery, for prevention of cardiorenal and metabolic complications in people with T2D or obesity, highlighting the contributions of weight loss, as well as weight loss-independent mechanisms of action. Collectively, the evidence supports a tailored approach to selection of therapeutic interventions for T2D and obesity based on the likelihood of developing specific complications, rather than a stepwise approach focused exclusively on glycemic or weight control.

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.

Mechanisms of weight loss-induced remission in people with prediabetes: a post-hoc analysis of the randomised, controlled, multicentre Prediabetes Lifestyle Intervention Study (PLIS)

BACKGROUND

Remission of type 2 diabetes can occur as a result of weight loss and is characterised by liver fat and pancreas fat reduction and recovered insulin secretion. In this analysis, we aimed to investigate the mechanisms of weight loss- induced remission in people with prediabetes.

METHODS

In this prespecified post-hoc analysis, weight loss-induced resolution of prediabetes in the randomised, controlled, multicentre Prediabetes Lifestyle Intervention Study (PLIS) was assessed, and the results were validated against participants from the Diabetes Prevention Program (DPP) study. For PLIS, between March 1, 2012, and Aug 31, 2016, participants were recruited from eight clinical study centres (including seven university hospitals) in Germany and randomly assigned to receive either a control intervention, a standard lifestyle intervention (ie, DPP-based intervention), or an intensified lifestyle intervention for 12 months. For DPP, participants were recruited from 23 clinical study centres in the USA between July 31, 1996, and May 18, 1999, and randomly assigned to receive either a standard lifestyle intervention, metformin, or placebo. In both PLIS and DPP, only participants who were randomly assigned to receive lifestyle intervention or placebo and who lost at least 5% of their bodyweight were included in this analysis. Responders were defined as people who returned to normal fasting plasma glucose (FPG; <5·6 mmol/L), normal glucose tolerance (<7·8 mmol/L), and HbA1c less than 39 mmol/mol after 12 months of lifestyle intervention or placebo or control intervention. Non-responders were defined as people who had FPG, 2 h glucose, or HbA1c more than these thresholds. The main outcomes for this analysis were insulin sensitivity, insulin secretion, visceral adipose tissue (VAT), and intrahepatic lipid content (IHL) and were evaluated via linear mixed models.

FINDINGS

Of 1160 participants recruited to PLIS, 298 (25·7%) had weight loss of 5% or more of their bodyweight at baseline. 128 (43%) of 298 participants were responders and 170 (57%) were non-responders. Responders were younger than non-responders (mean age 55·6 years [SD 9·9] vs 60·4 years [8·6]; p<0·0001). The DPP validation cohort included 683 participants who lost at least 5% of their bodyweight at baseline. Of these, 132 (19%) were responders and 551 (81%) were non-responders. In PLIS, BMI reduction was similar between responders and non-responders (responders mean at baseline 32·4 kg/m2 [SD 5·6] to mean at 12 months 29·0 kg/m2 [4·9] vs non-responders 32·1 kg/m2 [5·9] to 29·2 kg/m2 [5·4]; p=0·86). However, whole-body insulin sensitivity increased more in responders than in non-responders (mean at baseline 291 mL/[min × m2], SD 60 to mean at 12 months 378 mL/[min × m2], 56 vs 278 mL/[min × m2], 62, to 323 mL/[min × m2], 66; p<0·0001), whereas insulin secretion did not differ within groups over time or between groups (responders mean at baseline 175 pmol/mmol [SD 64] to mean at 12 months 163·7 pmol/mmol [60·6] vs non-responders 158·0 pmol/mmol [55·6] to 154·1 pmol/mmol [56·2]; p=0·46). IHL decreased in both groups, without a difference between groups (responders mean at baseline 10·1% [SD 8·7] to mean at 12 months 3·5% [3·9] vs non-responders 10·3% [8·1] to 4·2% [4·2]; p=0·34); however, VAT decreased more in responders than in non-responders (mean at baseline 6·2 L [SD 2·9] to mean at 12 months 4·1 L [2·3] vs 5·7 L [2·3] to 4·5 L [2·2]; p=0·0003). Responders had a 73% lower risk of developing type 2 diabetes than non-responders in the 2 years after the intervention ended.

INTERPRETATION

By contrast to remission of type 2 diabetes, resolution of prediabetes was characterised by an improvement in insulin sensitivity and reduced VAT. Because return to normal glucose regulation (NGR) prevents development of type 2 diabetes, we propose the concept of remission of prediabetes in analogy to type 2 diabetes. We suggest that remission of prediabetes should be the primary therapeutic aim in individuals with prediabetes.

FUNDING

German Federal Ministry for Education and Research via the German Center for Diabetes Research; the Ministry of Science, Research and the Arts Baden-Württemberg; the Helmholtz Association and Helmholtz Munich; the Cluster of Excellence Controlling Microbes to Fight Infections; and the German Research Foundation.

Relationship between the magnitude of body mass index reductions and remission in patients with type 2 diabetes in real world settings: Analysis of nationwide patient registry in Japan (JDDM74)

AIMS

To determine the association between the magnitude of weight loss and incidence of remission according to baseline characteristics in patients with diabetes in clinical settings.

METHODS

In total, 39 676 Japanese patients with type 2 diabetes aged ≥18 years with glycated haemoglobin (HbA1c) ≥6.5% and/or glucose-lowering drug prescription were identified from databases of specialists' clinics from 1989 and followed until September 2022. Remission was diagnosed as maintaining HbA1c <6.5% at least 3 months after cessation of a glucose-lowering drug. Factors associated with remission were evaluated by logistic regression analysis according to weight change in 1 year (i.e. ≥10%, 7.0-9.9%, 3.0-6.9% reduction, <3% change and ≥3.0% increase).

RESULTS

During the study period, 3454 remissions occurred. The rates of remission were higher in the group with the greatest reduction of body mass index (BMI) in any category examined (i.e. baseline BMI, HbA1c, duration of diabetes and treatment). The incidences of remission per 1000 person-years were about 25 and 50, respectively, for those with BMI ≥22.5 and reductions in BMI of 7.0-9.9% and ≥10% in 1 year. Remissions per 1000 person-years were 99.2 and 91.8, respectively, for those with baseline HbA1c of 6.5-6.9 and a 10% BMI reduction and those not taking glucose-lowering drugs accompanied by a 10% BMI reduction.

CONCLUSIONS

Modest weight losses of 3.0-7.9% were significantly associated with remission, but a minimum of 10% weight loss would be required in addition to an early diagnosis to achieve a 10% remission rate in clinical settings. Our results implied that remission may be expected with a relatively lower BMI in an Asian population compared with that was reported in Western populations if accompanied by weight loss.

Aetiology of Type 2 diabetes in people with a 'normal' body mass index: testing the personal fat threshold hypothesis

Weight loss in overweight or obese individuals with Type 2 diabetes (T2D) can normalize hepatic fat metabolism, decrease fatty acid oversupply to β cells and restore normoglycaemia. One in six people has BMI <27 kg/m2 at diagnosis, and their T2D is assumed to have different aetiology. The Personal Fat Threshold hypothesis postulated differing individual thresholds for lipid overspill and adverse effects on β-cell function. To test this hypothesis, people with Type 2 diabetes and body mass index <27kg/m2 (n = 20) underwent repeated 5% weight loss cycles. Metabolic assessments were carried out at stable weight after each cycle and after 12 months. To determine how closely metabolic features returned to normal, 20 matched normoglycemic controls were studied once. Between baseline and 12 months: BMI fell (mean ± SD), 24.8 ± 0.4 to 22.5 ± 0.4 kg/m2 (P<0.0001) (controls: 21.5 ± 0.5); total body fat, 32.1 ± 1.5 to 27.6 ± 1.8% (P<0.0001) (24.6 ± 1.5). Liver fat content and fat export fell to normal as did fasting plasma insulin. Post-meal insulin secretion increased but remained subnormal. Sustained diabetes remission (HbA1c < 48 mmol/mol off all glucose-lowering agents) was achieved by 70% (14/20) by initial weight loss of 6.5 (5.5-10.2)%. Correction of concealed excess intra-hepatic fat reduced hepatic fat export, with recovery of β-cell function, glycaemic improvement in all and return to a non-diabetic metabolic state in the majority of this group with BMI <27 kg/m2 as previously demonstrated for overweight or obese groups. The data confirm the Personal Fat Threshold hypothesis: aetiology of Type 2 diabetes does not depend on BMI. This pathophysiological insight has major implications for management.

Incidence and predictors of remission and relapse of type 2 diabetes mellitus in Japan: Analysis of a nationwide patient registry

AIMS

To determine the incidence of remission and 1-year relapse from remission and associated factors in patients with type 2 diabetes.

MATERIALS AND METHODS

A total of 48 320 Japanese patients with type 2 diabetes aged ≥18 years, with glycated haemoglobin (HbA1c) levels ≥48 mmol/mol (6.5%) and/or glucose-lowering drug prescription, were identified from databases of specialist clinics from 1989 and followed until September 2022. Remission was defined as HbA1c <48 mmol/mol at least 3 months after cessation of a glucose-lowering drug. Relapse was defined as failure to maintain remission for 1 year. Factors associated with remission and relapse were evaluated by logistic regression analysis.

RESULTS

The overall incidence of remissions per 1000 person-years was 10.5, and for those with HbA1c levels of 48 to 53 mmol/mol (6.5% to 6.9%), those taking no glucose-lowering drugs at baseline, and those with a ≥10% body mass index (BMI) reduction in 1 year, it was 27.8, 21.7 and 48.2, respectively. Shorter duration, lower baseline HbA1c, higher baseline BMI, higher BMI reduction at 1 year, and no glucose-lowering drugs at baseline were significantly associated with remission. Among 3677 persons with remission, approximately two-thirds (2490) relapsed within 1 year. Longer duration, lower BMI at baseline, and lower BMI reduction at 1 year were significantly associated with relapse.

CONCLUSIONS

The results showed that the incidence of remission and predictors of relapse, especially baseline BMI, might differ greatly between East Asian and Western populations. Furthermore, the relationships of BMI reduction with remission and relapse may be greater in East Asian than in Western populations, implying ethnic differences in returning from overt hyperglycaemia to nearly normal glucose levels.

Clinical expert consensus on the assessment and protection of pancreatic islet β-cell function in type 2 diabetes mellitus

Islet β-cell dysfunction is a basic pathophysiological characteristic of type 2 diabetes mellitus (T2DM). Appropriate assessment of islet β-cell function is beneficial to better management of T2DM. Protecting islet β-cell function is vital to delay the progress of type 2 diabetes mellitus. Therefore, the Pancreatic Islet β-cell Expert Panel of the Chinese Diabetes Society and Endocrinology Society of Jiangsu Medical Association organized experts to draft the "Clinical expert consensus on the assessment and protection of pancreatic islet β-cell function in type 2 diabetes mellitus." This consensus suggests that β-cell function can be clinically assessed using blood glucose-based methods or methods that combine blood glucose and endogenous insulin or C-peptide levels. Some measures, including weight loss and early and sustained euglycemia control, could effectively protect islet β-cell function, and some newly developed drugs, such as Sodium-glucose cotransporter-2 inhibitor and Glucagon-like peptide-1 receptor agonists, could improve islet β-cell function, independent of glycemic control.

Physiology Reconfigured: How Does Bariatric Surgery Lead to Diabetes Remission?

Bariatric surgery improves glucose homeostasis and glycemic control in patients with type 2 diabetes. Over the past 20 years, a breadth of studies has been conducted in humans and rodents aimed to identify the regulatory nodes responsible for surgical remission of type 2 diabetes. The review herein discusses central mechanisms of type 2 diabetes remission associated with weight loss and surgical modification of the gastrointestinal tract.

First-phase insulin secretion: can its evaluation direct therapeutic approaches?

Our work is aimed at unraveling the role of the first-phase insulin secretion in the natural history of type 2 diabetes mellitus (T2DM) and its interrelationship with insulin resistance and with β cell function and mass. Starting from pathophysiology, we investigate the impact of impaired secretion on glucose homeostasis and explore postmeal hyperglycemia as the main clinical feature, underlining its relevance in the management of the disease. We also review dietary and pharmacological approaches aimed at improving early secretory defects and restoring residual β cell function. Furthermore, we discuss possible approaches to detect early secretory defects in clinical practice. By providing a journey through human and animal data, we attempt a unification of the recent evidence in an effort to offer a new outlook on β cell secretion.

What predicts drug-free type 2 diabetes remission? Insights from an 8-year general practice service evaluation of a lower carbohydrate diet with weight loss

BACKGROUND

Type 2 diabetes (T2D) is often regarded as a progressive, lifelong disease requiring an increasing number of drugs. Sustained remission of T2D is now well established, but is not yet routinely practised. Norwood surgery has used a low-carbohydrate programme aiming to achieve remission since 2013.

METHODS

Advice on a lower carbohydrate diet and weight loss was offered routinely to people with T2D between 2013 and 2021, in a suburban practice with 9800 patients. Conventional 'one-to-one' GP consultations were used, supplemented by group consultations and personal phone calls as necessary. Those interested in participating were computer coded for ongoing audit to compare 'baseline' with 'latest follow-up' for relevant parameters.

RESULTS

The cohort who chose the low-carbohydrate approach (n=186) equalled 39% of the practice T2D register. After an average of 33 months median (IQR) weight fell from 97 (84-109) to 86 (76-99) kg, giving a mean (SD) weight loss of -10 (8.9)kg. Median (IQR) HbA1c fell from 63 (54-80) to 46 (42-53) mmol/mol. Remission of diabetes was achieved in 77% with T2D duration less than 1 year, falling to 20% for duration greater than 15 years. Overall, remission was achieved in 51% of the cohort. Mean LDL cholesterol decreased by 0.5 mmol/L, mean triglyceride by 0.9 mmol/L and mean systolic blood pressure by 12 mm Hg. There were major prescribing savings; average Norwood surgery spend was £4.94 per patient per year on drugs for diabetes compared with £11.30 for local practices. In the year ending January 2022, Norwood surgery spent £68 353 per year less than the area average.

CONCLUSIONS

A practical primary care-based method to achieve remission of T2D is described. A low-carbohydrate diet-based approach was able to achieve major weight loss with substantial health and financial benefit. It resulted in 20% of the entire practice T2D population achieving remission. It appears that T2D duration <1 year represents an important window of opportunity for achieving drug-free remission of diabetes. The approach can also give hope to those with poorly controlled T2D who may not achieve remission, this group had the greatest improvements in diabetic control as represented by HbA1c.

Weight loss and β-cell responses following gastric banding or pharmacotherapy in adults with impaired glucose tolerance or type 2 diabetes: a randomized trial

OBJECTIVE

The extent to which weight loss contributes to increases in insulin sensitivity (IS) and β-cell function after surgical or medical intervention has not been directly compared in individuals with impaired glucose tolerance or newly diagnosed type 2 diabetes.

METHODS

The Restoring Insulin Secretion (RISE) Study included adults in the Beta-Cell Restoration Through Fat Mitigation Study (n = 88 randomized to laparoscopic gastric banding or metformin [MET]) and the Adult Medication Study (n = 267 randomized to placebo, MET, insulin glargine/MET, or liraglutide + MET [L + M]). IS and β-cell responses were measured at baseline and after 12 months by modeling of oral glucose tolerance tests and during arginine-stimulated hyperglycemic clamps. Linear regression models assessed differences between and within treatments over time.

RESULTS

BMI decreased in all treatment groups, except placebo, at 12 months. IS increased in all arms except placebo and was inversely correlated with changes in BMI. L + M was the only treatment arm that enhanced multiple measures of β-cell function independent of weight loss. Insulin secretion decreased in the laparoscopic gastric banding arm proportional to increases in IS, with no net benefit on β-cell function.

CONCLUSIONS

Reducing demand on the β-cell by improving IS through weight loss does not reverse β-cell dysfunction. L + M was the only treatment that enhanced β-cell function.

Autotaxin signaling facilitates β cell dedifferentiation and dysfunction induced by Sirtuin 3 deficiency

Objective

β cell dedifferentiation may underlie the reversible reduction in pancreatic β cell mass and function in type 2 diabetes (T2D). We previously reported that β cell-specific Sirt3 knockout (Sirt3^f/f;Cre/+) mice developed impaired glucose tolerance and glucose-stimulated insulin secretion after feeding with high fat diet (HFD). RNA sequencing showed that Sirt3-deficient islets had enhanced expression of Enpp2 (Autotaxin, or ATX), a secreted lysophospholipase which produces lysophosphatidic acid (LPA). Here, we hypothesized that activation of the ATX/LPA pathway contributed to pancreatic β cell dedifferentiation in Sirt3-deficient β cells.

Methods

We applied LPA, or lysophosphatidylcoline (LPC), the substrate of ATX for producing LPA, to MIN6 cell line and mouse islets with altered Sirt3 expression to investigate the effect of LPA on β cell dedifferentiation and its underlying mechanisms. To examine the pathological effects of ATX/LPA pathway, we injected the β cell selective adeno-associated virus (AAV-Atx-shRNA) or negative control AAV-scramble in Sirt3^f/f and Sirt3^f/f;Cre/+ mice followed by 6-week of HFD feeding.

Results

In Sirt3^f/f;Cre/+ mouse islets and Sirt3 knockdown MIN6 cells, ATX upregulation led to increased LPC with increased production of LPA. The latter not only induced reversible dedifferentiation in MIN6 cells and mouse islets, but also reduced glucose-stimulated insulin secretion from islets. In MIN6 cells, LPA induced phosphorylation of JNK/p38 MAPK which was accompanied by β cell dedifferentiation. The latter was suppressed by inhibitors of LPA receptor, JNK, and p38 MAPK. Importantly, inhibiting ATX in vivo improved insulin secretion and reduced β cell dedifferentiation in HFD-fed Sirt3^f/f;Cre/+ mice.

Conclusions

Sirt3 prevents β cell dedifferentiation by inhibiting ATX expression and upregulation of LPA. These findings support a long-range signaling effect of Sirt3 which modulates the ATX-LPA pathway to reverse β cell dysfunction associated with glucolipotoxicity.

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Sirtuin 3 (Sirt3) deletion upregulates autotaxin/ATX, the enzyme converting lysophosphatidylcholine (LPC) to lysophosphatidic acid (LPA).

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LPA induces dedifferentiation in β cell line and primary islet through LPA receptor-MAPK p38 and JNK signaling.

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ATX knockdown ameliorates LPA induced β cell dedifferentiation and improves insulin secretion in obese Sirt3 knockout mice.

Effects of a 13-Week Personalized Lifestyle Intervention Based on the Diabetes Subtype for People with Newly Diagnosed Type 2 Diabetes

A type 2 diabetes mellitus (T2DM) subtyping method that determines the T2DM phenotype based on an extended oral glucose tolerance test is proposed. It assigns participants to one of seven subtypes according to their β-cell function and the presence of hepatic and/or muscle insulin resistance. The effectiveness of this subtyping approach and subsequent personalized lifestyle treatment in ameliorating T2DM was assessed in a primary care setting. Sixty participants, newly diagnosed with (pre)diabetes type 2 and not taking diabetes medication, completed the intervention. Retrospectively collected data of 60 people with T2DM from usual care were used as controls. Bodyweight (p < 0.01) and HbA1c (p < 0.01) were significantly reduced after 13 weeks in the intervention group, but not in the usual care group. The intervention group achieved 75.0% diabetes remission after 13 weeks (fasting glucose ≤ 6.9 mmol/L and HbA1c < 6.5% (48 mmol/mol)); for the usual care group, this was 22.0%. Lasting (two years) remission was especially achieved in subgroups with isolated hepatic insulin resistance. Our study shows that a personalized diagnosis and lifestyle intervention for T2DM in a primary care setting may be more effective in improving T2DM-related parameters than usual care, with long-term effects seen especially in subgroups with hepatic insulin resistance.

Intra-pancreatic fat deposition: bringing hidden fat to the fore

Development of advanced modalities for detection of fat within the pancreas has transformed understanding of the role of intra-pancreatic fat deposition (IPFD) in health and disease. There is now strong evidence for the presence of minimal (but not negligible) IPFD in healthy human pancreas. Diffuse excess IPFD, or fatty pancreas disease (FPD), is more frequent than type 2 diabetes mellitus (T2DM) (the most common disease of the endocrine pancreas) and acute pancreatitis (the most common disease of the exocrine pancreas) combined. FPD is not strictly a function of high BMI; it can result from the excess deposition of fat in the islets of Langerhans, acinar cells, inter-lobular stroma, acinar-to-adipocyte trans-differentiation or replacement of apoptotic acinar cells. This process leads to a wide array of diseases characterized by excess IPFD, including but not limited to acute pancreatitis, chronic pancreatitis, pancreatic cancer, T2DM, diabetes of the exocrine pancreas. There is ample evidence for FPD being potentially reversible. Weight loss-induced decrease of intra-pancreatic fat is tightly associated with remission of T2DM and its re-deposition with recurrence of the disease. Reversing FPD will open up opportunities for preventing or intercepting progression of major diseases of the exocrine pancreas in the future.

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.

Nutrient Regulation of Pancreatic Islet β-Cell Secretory Capacity and Insulin Production

Pancreatic islet β-cells exhibit tremendous plasticity for secretory adaptations that coordinate insulin production and release with nutritional demands. This essential feature of the β-cell can allow for compensatory changes that increase secretory output to overcome insulin resistance early in Type 2 diabetes (T2D). Nutrient-stimulated increases in proinsulin biosynthesis may initiate this β-cell adaptive compensation; however, the molecular regulators of secretory expansion that accommodate the increased biosynthetic burden of packaging and producing additional insulin granules, such as enhanced ER and Golgi functions, remain poorly defined. As these adaptive mechanisms fail and T2D progresses, the β-cell succumbs to metabolic defects resulting in alterations to glucose metabolism and a decline in nutrient-regulated secretory functions, including impaired proinsulin processing and a deficit in mature insulin-containing secretory granules. In this review, we will discuss how the adaptative plasticity of the pancreatic islet β-cell's secretory program allows insulin production to be carefully matched with nutrient availability and peripheral cues for insulin signaling. Furthermore, we will highlight potential defects in the secretory pathway that limit or delay insulin granule biosynthesis, which may contribute to the decline in β-cell function during the pathogenesis of T2D.

Mechanisms underlying the pathophysiology of type 2 diabetes: From risk factors to oxidative stress, metabolic dysfunction, and hyperglycemia

Type 2 diabetes (T2D) is a complex multifactorial disease that emerges from the combination of genetic and environmental factors, and obesity, lifestyle, and aging are the most relevant risk factors. Hyperglycemia is the main metabolic feature of T2D as a consequence of insulin resistance and β-cell dysfunction. Among the cellular alterations induced by hyperglycemia, the overproduction of reactive oxygen species (ROS) and consequently oxidative stress, accompanied by a reduced antioxidant response and impaired DNA repair pathways, represent essential mechanisms underlying the pathophysiology of T2D and the development of late complications. Mitochondrial dysfunction, endoplasmic reticulum (ER) stress, and inflammation are also closely correlated with insulin resistance and β-cell dysfunction. This review focus on the mechanisms by which oxidative stress, mitochondrial dysfunction, ER stress, and inflammation are involved in the pathophysiology of T2D, highlighting the importance of the antioxidant response and DNA repair mechanisms counteracting the development of the disease. Moreover, we indicate evidence on how nutritional interventions effectively improve diabetes care. Additionally, we address key molecular characteristics and signaling pathways shared between T2D and Alzheimer's disease (AD), which might probably be implicated in the risk of T2D patients to develop AD.

Body mass cycling and predictors of body mass regain and its impact on cardiometabolic health

Caloric restriction (CR) is the first line intervention to reduce adiposity and total body mass (BM) to improve insulin resistance and ameliorate metabolic derangements. However, the lost adipose mass is difficult to maintain reduced in the long term due to several factors including compensatory changes in orexigenic hormones, adipokine release, pro-inflammatory state, adipose tissue morphology, and resting metabolic rate as a consequence of the caloric deficit. Hence, most patients undergoing a BM reduction intervention ultimately regain the lost mass and too often additional adipose mass overtime, which is hypothesized to have increased deleterious effects chronically. In this mini-review we describe the effects of BM cycling (loss and regain) on insulin resistance and cardiometabolic health and factors that may predict BM regain in clinical studies. We also describe the factors that contribute to the chronic deleterious effects of BM cycling in rodent models of diet-induced obesity (DIO) and other metabolic defects. We conclude that most of the improvements in insulin resistance are observed after a profound loss in BM regardless of the diet and that BM cycling abrogates these beneficial effects. We also suggest that more BM cycling studies are needed in rodent models resembling the development of type 2 diabetes mellitus (T2DM) in humans.

The Pancreatic ß-cell Response to Secretory Demands and Adaption to Stress

Pancreatic β cells dedicate much of their protein translation capacity to producing insulin to maintain glucose homeostasis. In response to increased secretory demand, β cells can compensate by increasing insulin production capability even in the face of protracted peripheral insulin resistance. The ability to amplify insulin secretion in response to hyperglycemia is a critical facet of β-cell function, and the exact mechanisms by which this occurs have been studied for decades. To adapt to the constant and fast-changing demands for insulin production, β cells use the unfolded protein response of the endoplasmic reticulum. Failure of these compensatory mechanisms contributes to both type 1 and 2 diabetes. Additionally, studies in which β cells are "rested" by reducing endogenous insulin demand have shown promise as a therapeutic strategy that could be applied more broadly. Here, we review recent findings in β cells pertaining to the metabolic amplifying pathway, the unfolded protein response, and potential advances in therapeutics based on β-cell rest.

The β-cell glucose toxicity hypothesis: Attractive but difficult to prove

β cells in the hyperglycemic environment of diabetes have marked changes in phenotype and function that are largely reversible if glucose levels can be returned to normal. A leading hypothesis is that these changes are caused by the elevated glucose levels leading to the concept of glucose toxicity. Support for the glucose toxicity hypothesis is largely circumstantial, but little progress has been made in defining the responsible mechanisms. Then questions emerge that are difficult to answer. In the very earliest stages of diabetes development, there is a dramatic loss of glucose-induced first-phase insulin release (FPIR) with only trivial elevations of blood glucose levels. A related question is how impaired insulin action on target tissues such as liver, muscle and fat can cause increased insulin secretion. The existence of a sophisticated feedback mechanism between insulin secretion and insulin action on peripheral tissues driven by glucose has been postulated, but it has been difficult to measure increases in blood glucose levels that might have been expected. These complexities force us to challenge the simplicity of the glucose toxicity hypothesis and feedback mechanisms. It may turn out that glucose is somehow driving all of these changes, but we must develop new questions and experimental approaches to test the hypothesis.

Nutritional basis of type 2 diabetes remission

Roy Taylor and colleagues explain how type 2 diabetes can be reversed by weight loss and avoidance of weight regain

Type 2 diabetes and remission: practical management guided by pathophysiology

The twin cycle hypothesis postulated that type 2 diabetes was a result of excess liver fat causing excess supply of fat to the pancreas with resulting dysfunction of both organs. If this was so, the condition should be able to be returned to normal by calorie restriction. The Counterpoint study tested this prediction in short-duration type 2 diabetes and showed that liver glucose handling returned to normal within 7 days and that beta-cell function returned close to normal over 8 weeks. Subsequent studies have demonstrated the durability of remission from type 2 diabetes. Remarkably, during the first 12 months of remission, the maximum functional beta-cell mass returns completely to normal and remains so for at least 24 months, consistent with regain of insulin secretory function of beta cells which had dedifferentiated in the face of chronic nutrient oversupply. The likelihood of achieving remission after 15% weight loss has been shown to be mainly determined by the duration of diabetes, with responders having better beta-cell function at baseline. Remission is independent of BMI, underscoring the personal fat threshold concept that type 2 diabetes develops when an individual acquires more fat than can be individually tolerated even at a BMI which in the nonobese range. Observations on people of South Asian or Afro-American ethnicity confirm that substantial weight loss achieves remission in the same way as in the largely White Europeans studied in detail. Diagnosis of type 2 diabetes can now be regarded as an urgent signal that weight loss must be achieved to avoid a progressive decline of health.

Glucose-induced insulin secretion in isolated human islets: Does it truly reflect β-cell function in vivo?

BACKGROUND

Diabetes always involves variable degrees of β-cell demise and malfunction leading to insufficient insulin secretion. Besides clinical investigations, many research projects used rodent islets to study various facets of β-cell pathophysiology. Their important contributions laid the foundations of steadily increasing numbers of experimental studies resorting to isolated human islets.

SCOPE OF REVIEW

This review, based on an analysis of data published over 60 years of clinical investigations and results of more recent studies in isolated islets, addresses a question of translational nature. Does the information obtained in vitro with human islets fit with our knowledge of insulin secretion in man? The aims are not to discuss specificities of pathways controlling secretion but to compare qualitative and quantitative features of glucose-induced insulin secretion in isolated human islets and in living human subjects.

MAJOR CONCLUSIONS

Much of the information gathered in vitro can reliably be translated to the in vivo situation. There is a fairly good, though not complete, qualitative and quantitative coherence between insulin secretion rates measured in vivo and in vitro during stimulation with physiological glucose concentrations, but the concordance fades out under extreme conditions. Perplexing discrepancies also exist between insulin secretion in subjects with Type 2 diabetes and their islets studied in vitro, in particular concerning the kinetics. Future projects should ascertain that the experimental conditions are close to physiological and do not alter the function of normal and diabetic islets.

Molecular mechanisms of lipotoxicity-induced pancreatic β-cell dysfunction

Type 2 diabetes (T2D), a heterogeneous disorder derived from metabolic dysfunctions, leads to a glucose overflow in the circulation due to both defective insulin secretion and peripheral insulin resistance. One of the critical risk factor for T2D is obesity, which represents a global epidemic that has nearly tripled since 1975. Obesity is characterized by chronically elevated free fatty acid (FFA) levels, which cause deleterious effects on glucose homeostasis referred to as lipotoxicity. Here, we review the physiological FFA roles onto glucose-stimulated insulin secretion (GSIS) and the pathological ones affecting many steps of the mechanisms and modulation of GSIS. We also describe in vitro and in vivo experimental evidences addressing lipotoxicity in β-cells and the role of saturation and chain length of FFA on the potency of GSIS stimulation. The molecular mechanisms underpinning lipotoxic-β-cell dysfunction are also reviewed. Among them, endoplasmic reticulum stress, oxidative stress and mitochondrial dysfunction, inflammation, impaired autophagy and β-cell dedifferentiation. Finally therapeutic strategies for the β-cells dysfunctions such as the use of metformin, glucagon-like peptide 1, thiazolidinediones, anti-inflammatory drugs, chemical chaperones and weight are discussed.

β-Cell Dysfunction, Hepatic Lipid Metabolism, and Cardiovascular Health in Type 2 Diabetes: New Directions of Research and Novel Therapeutic Strategies

Cardiovascular disease (CVD) remains a major problem for people with type 2 diabetes mellitus (T2DM), and dyslipidemia is one of the main drivers for both metabolic diseases. In this review, the major pathophysiological and molecular mechanisms of β-cell dysfunction and recovery in T2DM are discussed in the context of abnormal hepatic lipid metabolism and cardiovascular health. (i) In normal health, continuous exposure of the pancreas to nutrient stimulus increases the demand on β-cells. In the long term, this will not only stress β-cells and decrease their insulin secretory capacity, but also will blunt the cellular response to insulin. (ii) At the pre-diabetes stage, β-cells compensate for insulin resistance through hypersecretion of insulin. This increases the metabolic burden on the stressed β-cells and changes hepatic lipoprotein metabolism and adipose tissue function. (iii) If this lipotoxic hyperinsulinemic environment is not removed, β-cells start to lose function, and CVD risk rises due to lower lipoprotein clearance. (iv) Once developed, T2DM can be reversed by weight loss, a process described recently as remission. However, the precise mechanism(s) by which calorie restriction causes normalization of lipoprotein metabolism and restores β-cell function are not fully established. Understanding the pathophysiological and molecular basis of β-cell failure and recovery during remission is critical to reduce β-cell burden and loss of function. The aim of this review is to highlight the link between lipoprotein export and lipid-driven β-cell dysfunction in T2DM and how this is related to cardiovascular health. A second aim is to understand the mechanisms of β-cell recovery after weight loss, and to explore new areas of research for developing more targeted future therapies to prevent T2DM and the associated CVD events.

Pathogenesis and remission of type 2 diabetes: what has the twin cycle hypothesis taught us?

Type 2 diabetes has been regarded a complex multifactorial disease that lead to serious health complications including high cardiovascular risks. The twin cycle hypothesis postulated that both hepatic insulin resistance and dysfunction rather than death of beta (β) cell determine diabetes onset. Several studies were carried out to test this hypothesis, and all demonstrated that chronic excess calorie intake and ectopic fat accumulation within the liver and pancreas are fundamental to the development of this disease. However, these recent research advances cannot determine the exact cause of this disease. In this review, the major factors that contribute to the pathogenesis and remission of type 2 diabetes will be outlined. Importantly, the effect of disordered lipid metabolism, characterized by altered hepatic triglyceride export will be discussed. Additionally, the observed changes in pancreas morphology in type 2 diabetes will be highlighted and discussed in relation to β cell function.

Continuous glucose monitoring in subjects undergoing bariatric surgery: Diurnal and nocturnal glycemic patterns

BACKGROUND AND AIMS

Although the use of Continuous Glucose Monitoring (CGM) is rapidly extending, little evidence is currently available on daily glycemic excursions after different bariatric procedures. We assessed glycemic patterns after sleeve gastrectomy (SG) and roux-en-Y gastric bypass (RYGB) using CGM.

METHODS AND RESULTS

Cross-sectional study in subjects who had undergone RYGB (n = 22) or SG (n = 29) since at least 1 year, without pre-surgery or in current diabetes (T2DM) remission. All subjects underwent 7 day-CGM (Dexcom G4 PLATINUM), which provides glucose variability (GV), number and time spent in hypoglycemia, hypoglycemia patterns (postprandial, nocturnal or mixed). All indexes of GV were higher after RYGB than after SG (p < 0.001). Twenty-eight (55%) subjects experienced hypoglycemia. The number of events was higher after RYGB than SG (p = 0.017) while it did not differ in subjects with or without pre-surgery T2DM (p = 0.129). Overall, 9 (32%) subjects presented hypoglycemia exclusively during the postprandial period, 8 (29%) an exclusively nocturnal pattern and 11 (39%) a mixed pattern. The nocturnal pattern was more frequent after SG than RYGB (53.8% vs 6.7%, p = 0.036) while no difference was observed in subjects with or without pre-surgery T2DM (p = 0.697). Hypoglycemia symptoms were more frequent in subjects with postprandial than in those with nocturnal pattern (77.8% vs 12.5%, p = 0.015).

CONCLUSIONS

RYGB is characterized by a greater GV and a higher number of hypoglycemia events mostly post-prandial and symptomatic, while SG is associated with nocturnal and often asymptomatic hypoglycemia. These findings suggest that post-bariatric hypoglycemia is a more complex, not exclusively, postprandial phenomenon.