Islets-on-Chip: A Tool for Real-Time Assessment of Islet Function Prior to Transplantation

Islet transplantation improves metabolic control in patients with unstable type 1 diabetes. Clinical outcomes have been improving over the last decade, and the widely used beta-score allows the evaluation of transplantation results. However, predictive pre-transplantation criteria of islet quality for clinical outcomes are lacking. In this proof-of-concept study, we examined whether characterization of the electrical activity of donor islets could provide a criterion. Aliquots of 8 human donor islets from the STABILOT study, sampled from islet preparations before transplantation, were characterized for purity and split for glucose-induced insulin secretion and electrical activity using multi-electrode-arrays. The latter tests glucose concentration dependencies, biphasic activity, hormones, and drug effects (adrenalin, GLP-1, glibenclamide) and provides a ranking of CHIP-scores from 1 to 6 (best) based on electrical islet activity. The analysis was performed online in real time using a dedicated board or offline. Grouping of beta-scores and CHIP-scores with high, intermediate, and low values was observed. Further analysis indicated correlation between CHIP-score and beta-score, although significance was not attained (R = 0.51, p = 0.1). This novel approach is easily implantable in islet isolation units and might provide means for the prediction of clinical outcomes. We acknowledge the small cohort size as the limitation of this pilot study.

[Place of the insulin pump for the treatment of type 2 diabetic patients]

Continuous subcutaneous insulin infusion devices, commonly called insulin pumps, have been used for the treatment of patients with type 1 diabetes for several years. The benefits on glycemic control and on the quality of life of these patients are clear and well documented in the literature. On the other hand, their use in insulin-requiring patients with type 2 diabetes is less widespread. However, studies have shown that this therapeutic option is safe and effective for this population as well. In all cases, individualized assessment and follow-up by a specialized multidisciplinary care team is necessary to support patients with type 2 diabetes for whom an insulin pump is considered. We propose to describe here the current state of this clinical practice.

Prolonged culture of human pancreatic islets under glucotoxic conditions changes their acute beta cell calcium and insulin secretion glucose response curves from sigmoid to bell-shaped

AIMS/HYPOTHESIS

The rapid remission of type 2 diabetes by a diet very low in energy correlates with a marked improvement in glucose-stimulated insulin secretion (GSIS), emphasising the role of beta cell dysfunction in the early stages of the disease. In search of novel mechanisms of beta cell dysfunction after long-term exposure to mild to severe glucotoxic conditions, we extensively characterised the alterations in insulin secretion and upstream coupling events in human islets cultured for 1-3 weeks at ~5, 8, 10 or 20 mmol/l glucose and subsequently stimulated by an acute stepwise increase in glucose concentration.

METHODS

Human islets from 49 non-diabetic donors (ND-islets) and six type 2 diabetic donors (T2D-islets) were obtained from five isolation centres. After shipment, the islets were precultured for 3-7 days in RPMI medium containing ~5 mmol/l glucose and 10% (vol/vol) heat-inactivated FBS with selective islet picking at each medium renewal. Islets were then cultured for 1-3 weeks in RPMI containing ~5, 8, 10 or 20 mmol/l glucose before measurement of insulin secretion during culture, islet insulin and DNA content, beta cell apoptosis and cytosolic and mitochondrial glutathione redox state, and assessment of dynamic insulin secretion and upstream coupling events during acute stepwise stimulation with glucose [NAD(P)H autofluorescence, ATP/(ATP+ADP) ratio, electrical activity, cytosolic Ca²⁺ concentration ([Ca²⁺]_c)].

RESULTS

Culture of ND-islets for 1-3 weeks at 8, 10 or 20 vs 5 mmol/l glucose did not significantly increase beta cell apoptosis or oxidative stress but decreased insulin content in a concentration-dependent manner and increased beta cell sensitivity to subsequent acute stimulation with glucose. Islet glucose responsiveness was higher after culture at 8 or 10 vs 5 mmol/l glucose and markedly reduced after culture at 20 vs 5 mmol/l glucose. In addition, the [Ca²⁺]_c and insulin secretion responses to acute stepwise stimulation with glucose were no longer sigmoid but bell-shaped, with maximal stimulation at 5 or 10 mmol/l glucose and rapid sustained inhibition above that concentration. Such paradoxical inhibition was, however, no longer observed when islets were acutely depolarised by 30 mmol/l extracellular K⁺. The glucotoxic alterations of beta cell function were fully reversible after culture at 5 mmol/l glucose and were mimicked by pharmacological activation of glucokinase during culture at 5 mmol/l glucose. Similar results to those seen in ND-islets were obtained in T2D-islets, except that their rate of insulin secretion during culture at 8 and 20 mmol/l glucose was lower, their cytosolic glutathione oxidation increased after culture at 8 and 20 mmol/l glucose, and the alterations in GSIS and upstream coupling events were greater after culture at 8 mmol/l glucose.

CONCLUSIONS/INTERPRETATION

Prolonged culture of human islets under moderate to severe glucotoxic conditions markedly increased their glucose sensitivity and revealed a bell-shaped acute glucose response curve for changes in [Ca²⁺]_c and insulin secretion, with maximal stimulation at 5 or 10 mmol/l glucose and rapid inhibition above that concentration. This novel glucotoxic alteration may contribute to beta cell dysfunction in type 2 diabetes independently from a detectable increase in beta cell apoptosis.

Direct reprogramming of human fibroblasts into insulin-producing cells using transcription factors

Direct lineage reprogramming of one somatic cell into another without transitioning through a progenitor stage has emerged as a strategy to generate clinically relevant cell types. One cell type of interest is the pancreatic insulin-producing β cell whose loss and/or dysfunction leads to diabetes. To date it has been possible to create β-like cells from related endodermal cell types by forcing the expression of developmental transcription factors, but not from more distant cell lineages like fibroblasts. In light of the therapeutic benefits of choosing an accessible cell type as the cell of origin, in this study we set out to analyze the feasibility of transforming human skin fibroblasts into β-like cells. We describe how the timed-introduction of five developmental transcription factors (Neurog3, Pdx1, MafA, Pax4, and Nkx2-2) promotes conversion of fibroblasts toward a β-cell fate. Reprogrammed cells exhibit β-cell features including β-cell gene expression and glucose-responsive intracellular calcium mobilization. Moreover, reprogrammed cells display glucose-induced insulin secretion in vitro and in vivo. This work provides proof-of-concept of the capacity to make insulin-producing cells from human fibroblasts via transcription factor-mediated direct reprogramming.

[Treatment of congestive heart failure in older persons and SGLT2 inhibitors - Having your patient's best interests at heart]

The treatment and management of heart failure (HF) are constantly evolving. The latest guidelines recommend the use of SGLT2 inhibitors (SGLT2i) as an integral part to treating HF with reduced ejection fraction (< 40%). However, given that the patients included in these trials do not reflect the heterogeneity of the health of many elderly patients, we recommend basing the therapeutic decision on the patient's state of frailty. If a SGLT2i treatment at a standard dose (10 mg 1x/day) is recommended for robust patients, we suggest initiating treatment at 5 mg 1x/day for vulnerable patients, and then after 1 month increasing the dose to 10 mg 1x/day. Finally, for dependent patients, we recommend therapeutic abstention in the absence of sufficient scientific evidence.

Canakinumab in patients with COVID-19 and type 2 diabetes - A multicentre, randomised, double-blind, placebo-controlled trial

BACKGROUND

Patients with type 2 diabetes and obesity have chronic activation of the innate immune system possibly contributing to the higher risk of hyperinflammatory response to SARS-CoV2 and severe COVID-19 observed in this population. We tested whether interleukin-1β (IL-1β) blockade using canakinumab improves clinical outcome.

METHODS

CanCovDia was a multicenter, randomised, double-blind, placebo-controlled trial to assess the efficacy of canakinumab plus standard-of-care compared with placebo plus standard-of-care in patients with type 2 diabetes and a BMI > 25 kg/m² hospitalised with SARS-CoV2 infection in seven tertiary-hospitals in Switzerland. Patients were randomly assigned 1:1 to a single intravenous dose of canakinumab (body weight adapted dose of 450-750 mg) or placebo. Canakinumab and placebo were compared based on an unmatched win-ratio approach based on length of survival, ventilation, ICU stay and hospitalization at day 29. This study is registered with ClinicalTrials.gov, NCT04510493.

FINDINGS

Between October 17, 2020, and May 12, 2021, 116 patients were randomly assigned with 58 in each group. One participant dropped out in each group for the primary analysis. At the time of randomization, 85 patients (74·6 %) were treated with dexamethasone. The win-ratio of canakinumab vs placebo was 1·08 (95 % CI 0·69-1·69; p = 0·72). During four weeks, in the canakinumab vs placebo group 4 (7·0%) vs 7 (12·3%) participants died, 11 (20·0 %) vs 16 (28·1%) patients were on ICU, 12 (23·5 %) vs 11 (21·6%) were hospitalised for more than 3 weeks, respectively. Median ventilation time at four weeks in the canakinumab vs placebo group was 10 [IQR 6.0, 16.5] and 16 days [IQR 14.0, 23.0], respectively. There was no statistically significant difference in HbA1c after four weeks despite a lower number of anti-diabetes drug administered in patients treated with canakinumab. Finally, high-sensitive CRP and IL-6 was lowered by canakinumab. Serious adverse events were reported in 13 patients (11·4%) in each group.

INTERPRETATION

In patients with type 2 diabetes who were hospitalised with COVID-19, treatment with canakinumab in addition to standard-of-care did not result in a statistically significant improvement of the primary composite outcome. Patients treated with canakinumab required significantly less anti-diabetes drugs to achieve similar glycaemic control. Canakinumab was associated with a prolonged reduction of systemic inflammation.

FUNDING

Swiss National Science Foundation grant #198415 and University of Basel. Novartis supplied study medication.

Real world hypoglycaemia related to glucose variability and Flash glucose scan frequency assessed from global FreeStyle Libre data

AIM

Flash glucose monitoring provides a range of glucose metrics. In the current study, we aim to identify those that indicate that glycaemic targets can be consistently met and contrast the total (t-CV) and within-day coefficient of variation (wd-CV) to guide the assessment of glucose variability and hypoglycaemia exposure.

METHODS

De-identified data from Flash readers were collected. The readers were sorted into 10 equally sized groups of scan frequency followed by quartiles of estimated A1c (eA1c). A similar grouping was performed for the total coefficient of variation (t-CV) and within-day coefficient of variation (wd-CV). In addition, analysis of the association of time below 54 mg/dl and glucose variability measured by t-CV and wd-CV was performed.

RESULTS

The dataset included 1 002 946 readers. Readers sorted by 10 equal groups of scan rate and quartiles by eA1c, t-CV and wd-CV represented 25 074 readers per group. The association of lower eA1c with higher time in range and reduced time above range was clear. The correlation of eA1c quartiles and time below range was not consistent. An association between glucose variability and hypoglycaemia was found. Both wd-CV and t-CV were associated with time below range. For achieving the consensus target of <1% time below 54 mg/dl, the associated wd-CV and t-CV values were 33.5% and 39.5%, respectively.

CONCLUSIONS

The type of CV reported by the different continuous glucose monitoring systems should be acknowledged. CV <36% might not be adequate to ensure low hypoglycaemia exposure. To our knowledge, the majority of continuous glucose monitoring reports the t-CV. Appropriate thresholds should be used to identify patients that would probably meet time below range targets (t-CV <40% or wd-CV <34%).

[Continuous glucose monitoring Respective roles of healthcare professionals and quick interpretation guide]

The use of continuous interstitial glucose measurement systems (CGM) has revolutionized the management of patients with diabetes for 15 years. This is true both for professional use (diagnostic CGM) and personal use for patients (therapeutic CGM). The role of health professionals - general practitioners, diabetologists, nurses, dieticians - is important to coordinate, with a specific role for each. The clinical situations are all different and the systematic analysis of the data has ideally to be carried out with the participation of the patient. These devices allow significant improvements in glycemic control, making this technology one of the most important advances in diabetes for many years.

[Rapid and ultrarapid insulins: when and how?]

Treatment combining long-acting and short-acting insulins is essential for people with type 1 diabetes, but may become also compulsory in other forms of diabetes in case of insulinopenia. The purpose of short-acting insulins is to mimic physiological insulin secretion in response to carbohydrate intake at meals. There is a delay between the injection and its action, sometimes limiting their use and effectiveness. Ultra-rapid insulins have been developed to more closely approximate the expected insulin response to a meal, through faster absorption. They do not improve diabetes control but allow more flexibility with mealtime injections. These new analogues are also an attractive alternative for use in insulin pumps.

The nuclear receptor REV-ERBα is implicated in the alteration of β-cell autophagy and survival under diabetogenic conditions

Pancreatic β-cell failure in type 2 diabetes mellitus (T2DM) is associated with impaired regulation of autophagy which controls β-cell development, function, and survival through clearance of misfolded proteins and damaged organelles. However, the mechanisms responsible for defective autophagy in T2DM β-cells remain unknown. Since recent studies identified circadian clock transcriptional repressor REV-ERBα as a novel regulator of autophagy in cancer, in this study we set out to test whether REV-ERBα-mediated inhibition of autophagy contributes to the β-cell failure in T2DM. Our study provides evidence that common diabetogenic stressors (e.g., glucotoxicity and cytokine-mediated inflammation) augment β-cell REV-ERBα expression and impair β-cell autophagy and survival. Notably, pharmacological activation of REV-ERBα was shown to phenocopy effects of diabetogenic stressors on the β-cell through inhibition of autophagic flux, survival, and insulin secretion. In contrast, negative modulation of REV-ERBα was shown to provide partial protection from inflammation and glucotoxicity-induced β-cell failure. Finally, using bioinformatic approaches, we provide further supporting evidence for augmented REV-ERBα activity in T2DM human islets associated with impaired transcriptional regulation of autophagy and protein degradation pathways. In conclusion, our study reveals a previously unexplored causative relationship between REV-ERBα expression, inhibition of autophagy, and β-cell failure in T2DM.

Ten-year outcomes of islet transplantation in patients with type 1 diabetes: Data from the Swiss-French GRAGIL network

To describe the 10-year outcomes of islet transplantation within the Swiss-French GRAGIL Network, in patients with type 1 diabetes experiencing high glucose variability associated with severe hypoglycemia and/or with functional kidney graft. We conducted a retrospective analysis of all subjects transplanted in the GRAGIL-1c and GARGIL-2 islet transplantation trials and analyzed components of metabolic control, graft function and safety outcomes over the 10-year period of follow-up. Forty-four patients were included between September 2003 and April 2010. Thirty-one patients completed a 10-year follow-up. Ten years after islet transplantation, median HbA1c was 7.2% (6.2-8.0) (55 mmol/mol [44-64]) versus 8.0% (7.1-9.1) (64 mmol/mol [54-76]) before transplantation (p < .001). Seventeen of 23 (73.9%) recipients were free of severe hypoglycemia, 1/21 patients (4.8%) was insulin-independent and median C-peptide was 0.6 ng/ml (0.2-1.2). Insulin requirements (UI/kg/day) were 0.3 (0.1-0.5) versus 0.5 (0.4-0.6) before transplantation (p < .001). Median (IQR) β-score was 1 (0-4) (p < .05 when comparing with pre-transplantation values) and 51.9% recipients had a functional islet graft at 10 years. With a 10-year follow-up in a multicentric network, islet transplantation provided sustained improvement of glycemic control and was efficient to prevent severe hypoglycemia in almost 75% of the recipients.

LDHA is enriched in human islet alpha cells and upregulated in type 2 diabetes

The lactate dehydrogenase isoform A (LDHA) is a key metabolic enzyme that preferentially catalyzes the conversion of pyruvate to lactate. Whereas LDHA is highly expressed in many tissues, its expression is turned off in the differentiated adult β-cell within the pancreatic islets. The repression of LDHA under normal physiological condition and its inappropriate upregulation under a diabetogenic environment is well-documented in rodent islets/β-cells but little is known about LDHA expression in human islet cells and whether its abundance is altered under diabetic conditions. Analysis of public single-cell RNA-seq (sc-RNA seq) data as well as cell type-specific immunolabeling of human pancreatic islets showed that LDHA was mainly localized in human α-cells while it is expressed at a very low level in β-cells. Furthermore, LDHA, both at mRNA and protein, as well as lactate production is upregulated in human pancreatic islets exposed to chronic high glucose treatment. Microscopic analysis of stressed human islets and autopsy pancreases from individuals with type 2 diabetes (T2D) showed LDHA upregulation mainly in human α-cells. Pharmacological inhibition of LDHA in isolated human islets enhanced insulin secretion under physiological conditions but did not significantly correct the deregulated secretion of insulin or glucagon under diabetic conditions.

[Basal insulin therapy in patients with type 2 diabetes]

Insulin therapy, often initiated after hygiene and dietary measures and non-insulin antidiabetics, is part of the treatment of patients with type 2 diabetes. Fear of injections or hypoglycemia often delays its implementation. However, its introduction is recommended in cases of poorly balanced diabetes despite a well-controlled therapeutic escalation but also in cases of acute imbalance. Introduction of insulin therapy requires patient education and close monitoring by the healthcare team. Type of insulin and its titration reduce the incidence of hypoglycemia in patients at risk. The determination of the fasting glycemic target - relative to HbA1c - for the titration of insulin is important to define for an optimal benefit (prevention of secondary complications)/risk (hypoglycemia, weight gain) balance.

[New-onset diabetes and novel targeted therapies against cancer]

New systemic cancer therapies are increasingly oriented towards specific signaling pathways involved in carcinogenesis. However, these new treatments may lead to disorders of glycemic homeostasis ranging from glucose intolerance, diabetes or the occurrence of severe acute hyperglycemic syndrome due to blockade of certain pathways common to glucose metabolism. This article discusses the estimated frequency of new-onset diabetes, the pathophysiological mechanisms as well as the diagnostic, therapeutic, monitoring and prognostic management of glycemic dysfunction in patients treated with these novel systemic cancer therapies.

SGLT2 Inhibitors, What the Emergency Physician Needs to Know: A Narrative Review

Canagliflozin, dapagliflozin, empagliflozin, and ertugliflozin belong to a class of antidiabetic treatments referred to as sodium-glucose cotransporter 2 inhibitors (SGLT2 inhibitors, or SGLT2is). SGLT2is are currently indicated in North America and in Europe in type 2 diabetes mellitus, especially in patients with cardiovascular (CV) disease, high CV risk, heart failure, or renal disease. In Europe, dapagliflozin is also approved as an adjunct to insulin in patients with type 1 diabetes mellitus. New data provide evidence for benefits in heart failure with reduced ejection fraction and chronic kidney disease, including in patients without diabetes. The use of SGLT2is is expected to increase, suggesting that a growing number of patients will present to the emergency departments with these drugs. Most common adverse events are easily treatable, including mild genitourinary infections and conditions related to volume depletion. However, attention must be paid to some potentially serious adverse events, such as hypoglycemia (when combined with insulin or insulin secretagogues), lower limb ischemia, and diabetic ketoacidosis. We provide an up-to-date practical guide highlighting important elements on the adverse effects of SGLT2is and their handling in some frequently encountered clinical situations such as acute heart failure and decompensated diabetes.

Impact of ischemia time on islet isolation success and posttransplantation outcomes: A retrospective study of 452 pancreas isolations

Many variables impact islet isolation, including pancreas ischemia time. The ischemia time upper limit that should be respected to avoid a negative impact on the isolation outcome is not well defined. We have performed a retrospective analysis of all islet isolations in our center between 2008 and 2018. Total ischemia time, cold ischemia time, and organ removal time were analyzed. Isolation success was defined as an islet yield ≥200 000 IEQ. Of the 452 pancreases included, 288 (64%) were successfully isolated. Probability of isolation success showed a significant decrease after 8 hours of total ischemia time, 7 hours of cold ischemia time, and 80 minutes of organ removal time. Although we observed an impact of ischemia time on islet yield, a probability of isolation success of 50% was still present even when total ischemia time exceeds 12 hours. Posttransplantation clinical outcomes were assessed in 32 recipients and no significant difference was found regardless of ischemia time. These data indicate that although shorter ischemia times are associated with better islet isolation outcomes, total ischemia time >12 hours can provide excellent results in appropriately selected donors.

Precision medicine in the era of artificial intelligence: implications in chronic disease management

Aberrant metabolism is the root cause of several serious health issues, creating a huge burden to health and leading to diminished life expectancy. A dysregulated metabolism induces the secretion of several molecules which in turn trigger the inflammatory pathway. Inflammation is the natural reaction of the immune system to a variety of stimuli, such as pathogens, damaged cells, and harmful substances. Metabolically triggered inflammation, also called metaflammation or low-grade chronic inflammation, is the consequence of a synergic interaction between the host and the exposome-a combination of environmental drivers, including diet, lifestyle, pollutants and other factors throughout the life span of an individual. Various levels of chronic inflammation are associated with several lifestyle-related diseases such as diabetes, obesity, metabolic associated fatty liver disease (MAFLD), cancers, cardiovascular disorders (CVDs), autoimmune diseases, and chronic lung diseases. Chronic diseases are a growing concern worldwide, placing a heavy burden on individuals, families, governments, and health-care systems. New strategies are needed to empower communities worldwide to prevent and treat these diseases. Precision medicine provides a model for the next generation of lifestyle modification. This will capitalize on the dynamic interaction between an individual's biology, lifestyle, behavior, and environment. The aim of precision medicine is to design and improve diagnosis, therapeutics and prognostication through the use of large complex datasets that incorporate individual gene, function, and environmental variations. The implementation of high-performance computing (HPC) and artificial intelligence (AI) can predict risks with greater accuracy based on available multidimensional clinical and biological datasets. AI-powered precision medicine provides clinicians with an opportunity to specifically tailor early interventions to each individual. In this article, we discuss the strengths and limitations of existing and evolving recent, data-driven technologies, such as AI, in preventing, treating and reversing lifestyle-related diseases.

SGLT2 is not expressed in pancreatic α- and β-cells, and its inhibition does not directly affect glucagon and insulin secretion in rodents and humans

Objective

Sodium-glucose cotransporter 2 (SGLT2) inhibitors (SGLT2i), or gliflozins, are anti-diabetic drugs that lower glycemia by promoting glucosuria, but they also stimulate endogenous glucose and ketone body production. The likely causes of these metabolic responses are increased blood glucagon levels, and decreased blood insulin levels, but the mechanisms involved are hotly debated. This study verified whether or not SGLT2i affect glucagon and insulin secretion by a direct action on islet cells in three species, using multiple approaches.

Methods

We tested the in vivo effects of two selective SGLT2i (dapagliflozin, empagliflozin) and a SGLT1/2i (sotagliflozin) on various biological parameters (glucosuria, glycemia, glucagonemia, insulinemia) in mice. mRNA expression of SGLT2 and other glucose transporters was assessed in rat, mouse, and human FACS-purified α- and β-cells, and by analysis of two human islet cell transcriptomic datasets. Immunodetection of SGLT2 in pancreatic tissues was performed with a validated antibody. The effects of dapagliflozin, empagliflozin, and sotagliflozin on glucagon and insulin secretion were assessed using isolated rat, mouse and human islets and the in situ perfused mouse pancreas. Finally, we tested the long-term effect of SGLT2i on glucagon gene expression.

Results

SGLT2 inhibition in mice increased the plasma glucagon/insulin ratio in the fasted state, an effect correlated with a decline in glycemia. Gene expression analyses and immunodetections showed no SGLT2 mRNA or protein expression in rodent and human islet cells, but moderate SGLT1 mRNA expression in human α-cells. However, functional experiments on rat, mouse, and human (29 donors) islets and the in situ perfused mouse pancreas did not identify any direct effect of dapagliflozin, empagliflozin or sotagliflozin on glucagon and insulin secretion. SGLT2i did not affect glucagon gene expression in rat and human islets.

Conclusions

The data indicate that the SGLT2i-induced increase of the plasma glucagon/insulin ratio in vivo does not result from a direct action of the gliflozins on islet cells.

•

Gliflozins (SGLT2 and SGLT1/2 inhibitors) increase plasma glucagon/insulin ratio.

•

SGLT2 is not expressed in rodent and human pancreatic α- and β-cells.

•

SGLT1 is however expressed in human α-cells.

•

SGLT2 and SGLT1/2 inhibitors do not directly affect glucagon and insulin secretion.

Differential sensitivity of human islets from obese versus lean donors to chronic high glucose or palmitate

BACKGROUND

Due to the shortage of multi-organ donors, human pancreatic islet transplantation has now been extended to islets originating from obese subjects. In this study, our aim is to compare the respective sensitivity of human islets from lean vs obese donors to chronic high glucose or high palmitate.

METHODS

Human islets were isolated from pancreases harvested from brain-dead multi-organ donors. Islets were cultured during 72 hours in the presence of moderate (16.7 mmol/L) or high (28 mmoL/L) glucose concentrations, or glucose (5.6 mmoL/L) and palmitate (0.4 mmoL/L), before measurement of their response to glucose.

RESULTS

We first observed a greater insulin response in islets from obese donors under both basal and high-glucose conditions, confirming their hyperresponsiveness to glucose. When islets from obese donors were cultured in the presence of moderate or high glucose concentrations, insulin response to glucose remained unchanged or was slightly reduced, as opposed to that observed in lean subjects. Moreover, culturing islets from obese donors with high palmitate also induced less reduction in insulin response to glucose than in lean subjects. This partial protection of obese islets is associated with less induction of inducible nitric oxide synthase in islets, together with a greater expression of the transcription factor forkhead box O1 (FOXO1).

CONCLUSIONS

Our data suggest that in addition to an increased sensitivity to glucose, islets from obese subjects can be considered as more resistant to glucose and fatty acid excursions and are thus valuable candidates for transplantation.

Targeting pancreatic islet PTP1B improves islet graft revascularization and transplant outcomes

Deficient vascularization is a major driver of early islet graft loss and one of the primary reasons for the failure of islet transplantation as a viable treatment for type 1 diabetes. This study identifies the protein tyrosine phosphatase 1B (PTP1B) as a potential modulator of islet graft revascularization. We demonstrate that grafts of pancreatic islets lacking PTP1B exhibit increased revascularization, which is accompanied by improved graft survival and function, and recovery of normoglycemia and glucose tolerance in diabetic mice transplanted with PTP1B-deficient islets. Mechanistically, we show that the absence of PTP1B leads to activation of hypoxia-inducible factor 1α-independent peroxisome proliferator-activated receptor γ coactivator 1α/estrogen-related receptor α signaling and enhanced expression and production of vascular endothelial growth factor A (VEGF-A) by β cells. These observations were reproduced in human islets. Together, these findings reveal that PTP1B regulates islet VEGF-A production and suggest that this phosphatase could be targeted to improve islet transplantation outcomes.

[Insulin pump treatment: For whom and how to set it up on an outpatient?]

Pump therapy has existed for over 40 years and provides a more flexible delivery of insulin. To date, almost 25% of type 1 diabetic patients have chosen this therapeutic option. In recent years, it has also been offered to patients with type 2 insulin-requiring diabetes. The choice of insulin pump is based on its indication, the patient's preference, lifestyle and knowledge of the disease. A risk of developing ketoacidosis in case of interruption of insulin delivery exists. Its implementation therefore requires a specialized interdisciplinary care team available in case of emergency.

[Post-transplantation diabetes in kidney transplant: from the diabetologist point of view]

Post-transplantation diabetes (PTDM) exposes to increased morbidity (cardiovascular or infectious complications, early graft dysfunction) and to a risk of premature death. Recognition of risk factors is essential for early and individualized care. The management of a PTDM requires the use of oral antidiabetic treatments (metformin or DPP4 inhibitors) or GLP1 receptor agonists for their favorable effects on weight and kidney that seem ideal in this context. Corticosteroid-induced diabetes or the rare occurrence of diabetic ketoacidosis require insulin therapy. In the long term, the main objective remains to integrate PTDM treatment in a more comprehensive management, targeting the reduction of cardiovascular risk of vulnerable transplant patients.

[Diabetes and COVID-19 infection]

Based on the epidemiological data currently available, diabetes does not seem to be a risk factor for infection with SARS-CoV-2 but may be associated with a more severe course. Diabetes is extremely common in older patients with co-morbidities who are at risk of unfavorable outcomes. As with any other infection, poorly controlled pre-existing diabetes can promote secondary infections and lead to acute complications related to hyperglycemia, worsened itself by the infection. It is important to advise patients to have enough diabetic equipment and supplies at home, to make regular blood glucose self-tests, and to contact a caregiver immediately in case of glycemic imbalance or signs of infection. Antidiabetic therapy may need adjustments following usual sick day rules. Insulin therapy should be considered to treat any persistent hyperglycemia in patients hospitalized for an acute infection.

Characterization of immortalized human islet stromal cells reveals a MSC-like profile with pancreatic features

BACKGROUND

Mesenchymal stromal cells (MSCs) represent an interesting tool to improve pancreatic islet transplantation. They have immunomodulatory properties and secrete supportive proteins. However, the functional properties of MSCs vary according to many factors such as donor characteristics, tissue origin, or isolation methods. To counteract this heterogeneity, we aimed to immortalize and characterize adherent cells derived from human pancreatic islets (hISCs), using phenotypic, transcriptomic, and functional analysis.

METHODS

Adherent cells derived from human islets in culture were infected with a hTERT retrovirus vector and then characterized by microarray hybridization, flow cytometry analysis, and immunofluorescence assays. Osteogenic, adipogenic, and chondrogenic differentiation as well as PBMC proliferation suppression assays were used to compare the functional abilities of hISCs and MSCs. Extracellular matrix (ECM) gene expression profile analysis was performed using the SAM (Significance Analysis of Microarrays) software, and protein expression was confirmed by western blotting.

RESULTS

hISCs kept an unlimited proliferative potential. They exhibited several properties of MSCs such as CD73, CD90, and CD105 expression and differentiation capacity. From a functional point of view, hISCs inhibited the proliferation of activated peripheral blood mononuclear cells. The transcriptomic profile of hISCs highly clusterized with bone marrow (BM)-MSCs and revealed a differential enrichment of genes involved in the organization of the ECM. Indeed, the expression and secretion profiles of ECM proteins including collagens I, IV, and VI, fibronectin, and laminins, known to be expressed in abundance around and within the islets, were different between hISCs and BM-MSCs.

CONCLUSION

We generated a new human cell line from pancreatic islets, with MSCs properties and retaining some pancreatic specificities related to the production of ECM proteins. hISCs appear as a very promising tool in islet transplantation by their availability (as a source of inexhaustible source of cells) and ability to secrete a supportive "pancreatic" microenvironment.

Characterization of Daily Glycemic Variability in Subjects with Type 1 Diabetes Using a Mixture of Metrics

Background: Glycemic variability (GV) is an important component of glycemic control for patients with type 1 diabetes (T1D). The inadequacy of existing measurements lies in the fact that they view the variability from different aspects, so that no consensus has been reached among physicians as to which metrics to use in practice. Moreover, although GV, from 1 day to another, can show very different patterns, few metrics have been dedicated to daily evaluations. Materials and Methods: A reference (stable glycemia) statistical model is built based on a combination of daily computed canonical glycemic control metrics including variability. The metrics are computed for subjects from the TRIMECO islet transplantation trial, selected when their β-score (composite score for grading success) is ≥6 after a transplantation. Then, for any new daily glycemia recording, its likelihood with respect to this reference model provides a multimetric score of daily GV severity. In addition, determining the likelihood value that best separates the daily glycemia with β-score = 0 from that with β-score ≥6, we propose an objective decision rule to classify daily glycemia into "stable" or "unstable." Results: The proposed characterization framework integrates multiple standard metrics and provides a comprehensive daily GV index, based on which, long-term variability evaluations and investigations on the implicit link between variability and β-score can be carried out. Evaluation, in a daily GV classification task, shows that the proposed method is highly concordant to the experience of diabetologists. Conclusion: A multivariate statistical model is proposed to characterize the daily GV of subjects with T1D. The model has the advantage to provide a single variability score that gathers the information power of a number of canonical scores, too partial to be used individually. A reliable decision rule to classify daily variability measurements into stable or unstable is also provided.

Respective Contributions of Glycemic Variability and Mean Daily Glucose as Predictors of Hypoglycemia in Type 1 Diabetes: Are They Equivalent?

OBJECTIVE

To evaluate the respective contributions of short-term glycemic variability and mean daily glucose (MDG) concentration to the risk of hypoglycemia in type 1 diabetes.

RESEARCH DESIGN AND METHODS

People with type 1 diabetes (n = 100) investigated at the University Hospital of Montpellier (France) underwent continuous glucose monitoring (CGM) on two consecutive days, providing a total of 200 24-h glycemic profiles. The following parameters were computed: MDG concentration, within-day glycemic variability (coefficient of variation for glucose [%CV]), and risk of hypoglycemia (presented as the percentage of time spent below three glycemic thresholds: 3.9, 3.45, and 3.0 mmol/L).

RESULTS

MDG was significantly higher, and %CV significantly lower (both P < 0.001), when comparing the 24-h glycemic profiles according to whether no time or a certain duration of time was spent below the thresholds. Univariate regression analyses showed that MDG and %CV were the two explanatory variables that entered the model with the outcome variable (time spent below the thresholds). The classification and regression tree procedure indicated that the predominant predictor for hypoglycemia was %CV when the threshold was 3.0 mmol/L. In people with mean glucose ≤7.8 mmol/L, the time spent below 3.0 mmol/L was shortest (P < 0.001) when %CV was below 34%.

CONCLUSIONS

In type 1 diabetes, short-term glycemic variability relative to mean glucose (i.e., %CV) explains more hypoglycemia than does mean glucose alone when the glucose threshold is 3.0 mmol/L. Minimizing the risk of hypoglycemia requires a %CV below 34%.

[Treatment of type 2 diabetes before, during and after metabolic surgery]

Metabolic surgery is becoming increasingly important in the treatment of obese and diabetic patients. Its impact is major on immediate post-operative glycemic control and adaptation of anti-diabetic treatments is necessary. Over time, a recurrence of diabetes may be observed and the choice of treatments to be reintroduced must take into account the surgery performed. By discussing pharmacological options during the preoperative, peri-operative and post-operative periods, this article provides a review of the literature on a subject for which few guidelines are currently proposed.

Glycemic variability indices can be used to diagnose islet transplantation success in type 1 diabetic patients

AIMS

High glycemic variability (GV) is the major indication for islet transplantation (IT) in patients with type 1 diabetes (T1D). The actual criteria used to assess graft function do not consider GV improvement. Our study aimed to describe GV indices' evolution in T1D patients who benefited from IT during the TRIMECO trial and to evaluate if thresholds might be defined to diagnose IT success.

METHODS

We collected data from 29 patients of the TRIMECO trial, a clinical trial (NCT01148680) comparing the metabolic efficacy of IT with intensive insulin therapy. Based on CGM data, we analyzed mean glucose level and four GV indices (standard deviation, coefficient of variation, MAGE and GVP) before (M0) and 6 months (M6) after IT.

RESULTS

Each GV index decreased significantly between M0 and M6: SD 53.9 mg/dL [44.6-61.5] versus 20.1 mg/dL [13.5-24.3]; CV 35.2% [30.6-37.7] versus 17.3% [12.0-20.5]; MAGE 134.9 mg/dl [111.2-155.8] versus 51.9 mg/dL [32.4-62.4]; GVP 35.3% [24.9-47.2] versus 12.2% [6.2-18.8] (p ≤ 0.0001). Thresholds diagnosing IT success at 6 months post-transplant were an SD at 22.76 mg/dL (sensibility 88.89%, specificity 80.00%), a CV at 17.47% (sensibility 88.89%, specificity 70.00%), a MAGE at 54.81 mg/dL (sensibility 88.89%, specificity 80.00%) and a GVP at 12.27% (sensibility 88.89%, specificity 70.00%).

CONCLUSIONS

This study confirms a positive impact of IT on GV. The proposed thresholds allow an easy evaluation of IT success using only CGM data and may be a clinical tool for the follow-up of transplanted patients.

[Should patients with type 2 diabetes be screened for lower extremity arterial disease?]

Lower extremity arterial disease (LEAD) is a serious and invalidating disease with a relatively high prevalence in the diabetic population. Patients suffering from both conditions have a less favourable prognosis of affected limbs compared to non-diabetic patients, with more frequent adverse limb events such as amputations. Nevertheless, awareness of LEAD remains sub-optimal in the diabetic population. Regular and appropriate screening for this condition is therefore recommended. Affected individuals should receive optimal medical treatment, including intensive management of the various cardiovascular risk factors and strict blood glucose control.

Islet transplantation versus insulin therapy in patients with type 1 diabetes with severe hypoglycaemia or poorly controlled glycaemia after kidney transplantation (TRIMECO): a multicentre, randomised controlled trial

BACKGROUND

Islet transplantation is indicated for patients with type 1 diabetes with severe hypoglycaemia or after kidney transplantation. We did a randomised trial to assess the efficacy and safety of islet transplantation compared with insulin therapy in these patients.

METHODS

In this multicentre, open-label, randomised controlled trial, we randomly assigned (1:1) patients with type 1 diabetes at 15 university hospitals to receive immediate islet transplantation or intensive insulin therapy (followed by delayed islet transplantation). Eligible patients were aged 18-65 years and had severe hypoglycaemia or hypoglycaemia unawareness, or kidney grafts with poor glycaemic control. We used computer-generated randomisation, stratified by centre and type of patient. Islet recipients were scheduled to receive 11 000 islet equivalents per kg bodyweight in one to three infusions. The primary outcome was proportion of patients with a modified β-score (in which an overall score of 0 was not allocated when stimulated C-peptide was negative) of 6 or higher at 6 months after first islet infusion in the immediate transplantation group or 6 months after randomisation in the insulin group. The primary analysis included all patients who received the allocated intervention; safety was assessed in all patients who received islet infusions. This trial is registered with ClinicalTrials.gov, number NCT01148680, and is completed.

FINDINGS

Between July 8, 2010, and July 29, 2013, 50 patients were randomly assigned to immediate islet transplantation (n=26) or insulin treatment (n=24), of whom three (one in the immediate islet transplantation group and two in the insulin therapy group) did not receive the allocated intervention. Median follow-up was 184 days (IQR 181-186) in the immediate transplantation group and 185 days (172-201) in the insulin therapy group. At 6 months, 16 (64% [95% CI 43-82]) of 25 patients in the immediate islet transplantation group had a modified β-score of 6 or higher versus none (0% [0-15]) of the 22 patients in the insulin group (p<0·0001). At 12 months after first infusion, bleeding complications had occurred in four (7% [2-18]) of 55 infusions, and a decrease in median glomerular filtration rate from 90·5 mL/min (IQR 76·6-94·0) to 71·8 mL/min (59·0-89·0) was observed in islet recipients who had not previously received a kidney graft and from 63·0 mL/min (55·0-71·0) to 57·0 mL/min (45·5-65·1) in islet recipients who had previously received a kidney graft.

INTERPRETATION

For the indications assessed in this study, islet transplantation effectively improves metabolic outcomes. Although studies with longer-term follow-up are needed, islet transplantation seems to be a valid option for patients with severe, unstable type 1 diabetes who are not responding to intensive medical treatments. However, immunosuppression can affect kidney function, necessitating careful selection of patients.

FUNDING

Programme Hospitalier de Recherche Clinique grant from the French Government.

Proteasomal degradation of the histone acetyl transferase p300 contributes to beta-cell injury in a diabetes environment

In type 2 diabetes, amyloid oligomers, chronic hyperglycemia, lipotoxicity, and pro-inflammatory cytokines are detrimental to beta-cells, causing apoptosis and impaired insulin secretion. The histone acetyl transferase p300, involved in remodeling of chromatin structure by epigenetic mechanisms, is a key ubiquitous activator of the transcriptional machinery. In this study, we report that loss of p300 acetyl transferase activity and expression leads to beta-cell apoptosis, and most importantly, that stress situations known to be associated with diabetes alter p300 levels and functional integrity. We found that proteasomal degradation is the mechanism subserving p300 loss in beta-cells exposed to hyperglycemia or pro-inflammatory cytokines. We also report that melatonin, a hormone produced in the pineal gland and known to play key roles in beta-cell health, preserves p300 levels altered by these toxic conditions. Collectively, these data imply an important role for p300 in the pathophysiology of diabetes.

Pancreas preservation fluid microbial contamination is associated with poor islet isolation outcomes - a multi-centre cohort study

The microbiological safety of islet preparations is paramount. Preservation medium contamination is frequent, and its impact on islet yield and function remains unclear. Microbiological samples collected during islet isolations from 2006 to 2016 were analyzed and correlated to isolation and allo- and autotransplantation outcomes. Microbial contamination of preservation medium was found in 64.4% of processed donor pancreases (291/452). We identified 464 microorganisms including Staphylococcus (253/464, 54.5%), Streptococcus (31/464, 6.7%), and Candida species (25/464, 5.4%). Microbial contamination was associated with longer warm and cold ischemia times and lower numbers of postpurification islet equivalents, purity, transplant rate, and stimulation index (all P < 0.05). Six percent of the preparations accepted for transplantation showed microbial contamination after isolation (12/200); 9 of 12 were Candida species. Six patients were transplanted with a sample with late microbial growth discovered after the infusion. Insulin independence rate was not affected. This risk of transplanting a contaminated islets preparation was reduced by half following the implementation of an additional sampling after 24 h of islet culture. Pancreas preservation fluid microbial contamination is associated with lower transplant rate and poorer in vitro function, but not with changes in graft survival. Culture medium testing 1 day after isolation reduces the risk of incidental transplantation with contaminated islets.

The Second Phase of Insulin Secretion in Nondiabetic Islet-Grafted Recipients Is Altered and Can Predict Graft Outcome

CONTEXT

Islet transplantation (IT) can treat patients with severely unstable type 1 diabetes. Prehepatic kinetics of insulin secretion (ISec) in two phases can be calculated by C-peptide levels during meal tests. We proposed to describe the ISec profile after a mixed-meal tolerance test (MMTT) in IT recipients and to determine whether the calculated ISec indexes can predict graft outcome.

METHODS

We analyzed 34 MMTT among 11 patients who underwent IT between 2011 and 2016 and compared them with healthy controls and patients with type 2 diabetes (T2D). ISec indexes and insulin sensitivity were calculated from models of Van Cauter, Breda, and Mari after MMTT. Graft success was defined by total insulin independence without any criteria for diabetes.

RESULTS

In patients with successful IT, the first- and second-phase ISec indexes were lower than those of controls (P < 0.001) and did not differ from those of the T2D group. Nevertheless, insulin sensitivity of IT recipients was similar to that of the control group and higher than that of the T2D group. The index of the second phase of ISec ɸS was correlated with total infused islet equivalents (IEQs), was a good predictor of diabetes (re)occurrence, and allowed us to calculate 9500 IEQ/kg as the minimum needed to reach insulin independence.

CONCLUSION

We showed that indexes from the first and second phases of ISec are altered in insulin-independent IT recipients. Higher sensitivity distinguishes them from patients with T2D. Even in insulin-independent patients, IT remains a marginal mass model. Moreover, ɸS can estimate transplanted islet mass and predict IT recipient outcomes.

Toward Defining the Threshold Between Low and High Glucose Variability in Diabetes

OBJECTIVE

To define the threshold for excess glucose variability (GV), one of the main features of dysglycemia in diabetes.

RESEARCH DESIGN AND METHODS

A total of 376 persons with diabetes investigated at the University Hospital of Montpellier (Montpellier, France) underwent continuous glucose monitoring. Participants with type 2 diabetes were divided into several groups-groups 1, 2a, 2b, and 3 (n = 82, 28, 65, and 79, respectively)-according to treatment: 1) diet and/or insulin sensitizers alone; 2) oral therapy including an insulinotropic agent, dipeptidyl peptidase 4 inhibitors (group 2a) or sulfonylureas (group 2b); or 3) insulin. Group 4 included 122 persons with type 1 diabetes. Percentage coefficient of variation for glucose (%CV = [(SD of glucose)/(mean glucose)] × 100) and frequencies of hypoglycemia (interstitial glucose <56 mg/dL [3.1 mmol/L]) were computed.

RESULTS

Percentages of CV (median [interquartile range]; %) increased significantly (P < 0.0001) from group 1 (18.1 [15.2-23.9]) to group 4 (37.2 [31.0-42.3]). In group 1, the upper limit of %CV, which served as reference for defining excess GV, was 36%. Percentages of patients with %CVs above this threshold in groups 2a, 2b, 3, and 4 were 0, 12.3, 19.0, and 55.7%, respectively. Hypoglycemia was more frequent in group 2b (P < 0.01) and groups 3 and 4 (P < 0.0001) when subjects with a %CV >36% were compared with those with %CV ≤36%.

CONCLUSIONS

A %CV of 36% appears to be a suitable threshold to distinguish between stable and unstable glycemia in diabetes because beyond this limit, the frequency of hypoglycemia is significantly increased, especially in insulin-treated subjects.

Randomised, prospective, medico-economic nationwide French study of islet transplantation in patients with severely unstable type 1 diabetes: the STABILOT study protocol

INTRODUCTION

Islet transplantation may be an appropriate treatment option for patients with severely unstable type 1 diabetes experiencing major glucose variability with severe hypoglycaemia despite intensive insulin therapy. Few data are available on the costs associated with islet transplantation in relation to its benefits. The STABILOT study proposes to assess the economic impact of islet transplantation in comparison with the current best medical treatment defined as sensor-augmented pump (SAP) therapy.

METHODS

The trial will adopt an open-label, randomised, multicentred design. The study will include 30 patients with severely unstable type 1 diabetes. Eligible participants will be 18-65 years old, with type 1 diabetes duration >5 years, a negative basal or stimulated C-peptide, and severe instability defined by persistent, recurrent and disabling severe hypoglycaemia, despite optimised medical treatment. Participants will be randomised into two groups: one group with immediate registration for islet transplantation, and one group with delayed registration for 1 year while patients receive SAP therapy. The primary endpoint will be the incremental cost-utility ratio at 1 year between islet transplantation and SAP therapy. Perspectives of both the French Health Insurance System and the hospitals will be retained.

ETHICS AND DISSEMINATION

Ethical approval has been obtained at all sites. The trial has been approved by ClinicalTrials.gov (Trial registration ID NCT02854696). All participants will sign a free and informed consent form before randomisation. Results of the study will be communicated during national and international meetings in the field of diabetes and transplantation. A publication will be sought in journals usually read by physicians involved in diabetes care, transplantation and internal medicine.

TRIAL REGISTRATION NUMBER

NCT02854696; Pre-results.

Alloimmune Monitoring After Islet Transplantation: A Prospective Multicenter Assessment of 25 Recipients

Islet transplantation is an effective treatment for selected patients with type 1 diabetes. However, an accurate test still lacks for the early detection of graft rejection. Blood samples were prospectively collected in four university centers (Geneva, Grenoble, Montpellier, and Strasbourg). Peripheral blood mononuclear cells were stimulated with donor splenocytes in the presence of interleukin-2. After 24 h of incubation, interferon- (IFN-) ELISpot analysis was performed. After a total of 5 days of incubation, cell proliferation was assessed by fluorescence-activated cell sorting (FACS) analysis for Ki-67. Immunological events were correlated with adverse metabolic events determined by loss of 1 point of -score and/or an increased insulin intake 10%. Twenty-five patients were analyzed; 14 were recipients of islets alone, and 11 combined with kidney. Overall, 76% (19/25) reached insulin independence at one point during a mean follow-up of 30.7 months. IFN- ELISpot showed no detectable correlation with adverse metabolic events [area under the curve (AUC)=0.57]. Similarly, cell proliferation analysis showed no detectable correlation with adverse metabolic events (CD3+/CD4+ AUC=0.54; CD3+/CD8+ AUC=0.55; CD3/CD56+ AUC=0.50). CD3/CD56+ cell proliferation was significantly higher in patients with combined kidney transplantation versus islet alone (6 months, p=0.010; 12 months, p=0.016; and 24 months, p=0.018). Donor antigen-stimulated IFN- production and cell proliferation do not predict adverse metabolic events after islet transplantation. This suggests that the volume of transplanted islets is too small to produce a detectable systemic immune response and/or that alloimmune rejection is not the sole reason for the loss of islet graft function.

Five-Year Metabolic, Functional, and Safety Results of Patients With Type 1 Diabetes Transplanted With Allogenic Islets Within the Swiss-French GRAGIL Network

OBJECTIVE

To describe the 5-year outcomes of islet transplantation within the Swiss-French GRAGIL Network.

RESEARCH DESIGN AND METHODS

Retrospective analysis of all subjects enrolled in the GRAGIL-1c and GRAGIL-2 islet transplantation trials. Parameters related to metabolic control, graft function, and safety outcomes were studied.

RESULTS

Forty-four patients received islet transplantation (islet transplantation alone [ITA] 24 patients [54.5%], islet after kidney [IAK] transplantation 20 patients [45.5%]) between September 2003 and April 2010. Recipients received a total islet mass of 9,715.75 ± 3,444.40 IEQ/kg. Thirty-four patients completed a 5-year follow-up, and 10 patients completed a 4-year follow-up. At 1, 4, and 5 years after islet transplantation, respectively, 83%, 67%, and 58% of the ITA recipients and 80%, 70%, and 60% of the IAK transplant recipients reached HbA1c under 7% (53 mmol/mol) and were free of severe hypoglycemia, while none of the ITA recipients and only 10% of the IAK transplant recipients met this composite criterion at the preinfusion stage. Thirty-three of 44 patients (75%) experienced insulin independence during the entire follow-up period, with a median duration of insulin independence of 19.25 months (interquartile range 2-58). Twenty-nine of 44 recipients (66%) exhibited at least one adverse event; 18 of 55 adverse events (33%) were possibly related to immunosuppression; and complications related to the islet infusion (n = 84) occurred in 10 recipients (11.9%).

CONCLUSIONS

In a large cohort with a 5-year follow-up and in a multicenter network setting, islet transplantation was safe and efficient in restoring good and lasting glycemic control and preventing severe hypoglycemia in patients with type 1 diabetes.

Correction: proteasome dysfunction mediates high glucose-induced apoptosis in rodent Beta cells and human islets

[This corrects the article DOI: 10.1371/journal.pone.0092066.].

Proteasome dysfunction mediates high glucose-induced apoptosis in rodent beta cells and human islets

The ubiquitin/proteasome system (UPS), a major cellular protein degradation machinery, plays key roles in the regulation of many cell functions. Glucotoxicity mediated by chronic hyperglycaemia is detrimental to the function and survival of pancreatic beta cells. The aim of our study was to determine whether proteasome dysfunction could be involved in beta cell apoptosis in glucotoxic conditions, and to evaluate whether such a dysfunction might be pharmacologically corrected. Therefore, UPS activity was measured in GK rats islets, INS-1E beta cells or human islets after high glucose and/or UPS inhibitor exposure. Immunoblotting was used to quantify polyubiquitinated proteins, endoplasmic reticulum (ER) stress through CHOP expression, and apoptosis through the cleavage of PARP and caspase-3, whereas total cell death was detected through histone-associated DNA fragments measurement. In vitro, we found that chronic exposure of INS-1E cells to high glucose concentrations significantly decreases the three proteasome activities by 20% and leads to caspase-3-dependent apoptosis. We showed that pharmacological blockade of UPS activity by 20% leads to apoptosis in a same way. Indeed, ER stress was involved in both conditions. These results were confirmed in human islets, and proteasome activities were also decreased in hyperglycemic GK rats islets. Moreover, we observed that a high glucose treatment hypersensitized beta cells to the apoptotic effect of proteasome inhibitors. Noteworthily, the decreased proteasome activity can be corrected with Exendin-4, which also protected against glucotoxicity-induced apoptosis. Taken together, our findings reveal an important role of proteasome activity in high glucose-induced beta cell apoptosis, potentially linking ER stress and glucotoxicity. These proteasome dysfunctions can be reversed by a GLP-1 analog. Thus, UPS may be a potent target to treat deleterious metabolic conditions leading to type 2 diabetes.

Continuous glucose monitoring after kidney transplantation in non-diabetic patients: early hyperglycaemia is frequent and may herald post-transplantation diabetes mellitus and graft failure

OBJECTIVES

New onset of diabetes after transplantation (NODAT) is a known complication of renal transplantation, but early glycaemic status after transplantation has not been described prospectively. This study aimed to assess blood glucose (BG) levels immediately following kidney transplantation in non-diabetic subjects and to explore their relationship to later graft outcomes and NODAT occurrence.

PATIENTS AND METHODS

Over a 9-month period, 43 consecutive non-diabetic patients who received a kidney transplant were prospectively investigated. During the first 4 days after transplantation, fasting BG was measured and the 24-h BG profile assessed by continuous glucose monitoring (CGM). Capillary BG was measured on hospital admittance and at least four times a day for CGM calibration thereafter. All adverse events were recorded, and fasting BG and HbA1c were assessed at 3, 6 and 12 months and at the last visit to our centre.

RESULTS

Immediately following renal transplantation, capillary BG was 12.2 ± 3.8 mmol/L. On day 1 (D1), fasting BG was 9.9 ± 4.3 mmol/L and decreased to 6.0 ± 1.5 mmol/L on D3. The CGM-reported mean 24-h BG (mmol/L) was 10.2±2.4 on D1, 7.7 ± 1.3 on D2 and 7.5 ± 1.1 on D3. From D1 to D4, 43% of patients spent>12h/day with BG levels>7.7 mmol/L. While morbidity during the 3 months following transplantation appeared unrelated to BG, the first post-transplantation capillary BG measurement and fasting BG on D1 tended to be higher in patients who developed diabetes 3 months later. Tacrolimus treatment was associated with a higher incidence of dysglycaemia at 3 and 6 months. After a mean follow-up of 72 months, NODAT was frequently seen (18.6%), and was associated with tacrolimus medication (P<0.01) and a higher rate of renal transplantation failure (RR: 3.6, P<0.02).

CONCLUSION

Hyperglycaemia appears to be a nearly constant characteristic immediately following transplantation in non-diabetic kidney recipients. Higher BG values could identify patients at risk for later post-transplant diabetes and graft failure.

Short-term intravenous insulin infusion is associated with reduced expression of NADPH oxidase p47(phox) subunit in monocytes from type 2 diabetes patients

Hyperglycemia is a well-known inducing factor of oxidative stress through activation of NADPH oxidase. In addition to its plasma glucose lowering effect, insulin may also have antioxidant activity and was shown to downregulate NADPH oxidase expression in vitro. In this study, we show that a short-term (3-day) intravenous insulin infusion in patients with type 2 diabetes induces normalization of both glycemia and mRNA expression of circulating monocyte p47(phox) subunit.