Recent-onset Type Research Articles

Beta cell extracellular vesicle PD-L1 as a novel regulator of CD8+ T cell activity and biomarker during the evolution of type 1 diabetes.

Surviving beta cells in type 1 diabetes respond to inflammation by upregulating programmed death-ligand 1 (PD-L1) to engage immune cell programmed death protein 1 (PD-1) and limit destruction by self-reactive immune cells. Extracellular vesicles (EVs) and their cargo can serve as biomarkers of beta cell health and contribute to islet intercellular communication. We hypothesised that the inflammatory milieu of type 1 diabetes increases PD-L1 in beta cell EV cargo and that EV PD-L1 may protect beta cells against immune-mediated cell death. Beta cell lines and human islets were treated with proinflammatory cytokines to model the proinflammatory type 1 diabetes microenvironment. EVs were isolated using ultracentrifugation or size exclusion chromatography and analysed via immunoblot, flow cytometry and ELISA. EV PD-L1 binding to PD-1 was assessed using a competitive binding assay and in vitro functional assays testing the ability of EV PD-L1 to inhibit NOD CD8+ T cells. Plasma EV and soluble PD-L1 were assayed in the plasma of islet autoantibody-positive (Ab+) individuals or individuals with recent-onset type 1 diabetes and compared with levels in non-diabetic control individuals. PD-L1 protein co-localised with tetraspanin-associated proteins intracellularly and was detected on the surface of beta cell EVs. Treatment with IFN-α or IFN-γ for 24 h induced a twofold increase in EV PD-L1 cargo without a corresponding increase in the number of EVs. IFN exposure predominantly increased PD-L1 expression on the surface of beta cell EVs and beta cell EV PD-L1 showed a dose-dependent capacity to bind PD-1. Functional experiments demonstrated specific effects of beta cell EV PD-L1 to suppress proliferation and cytotoxicity of murine CD8+ T cells. Plasma EV PD-L1 levels were increased in Ab+individuals, particularly in those positive for a single autoantibody. Additionally, in Ab+ individuals or those who had type 1 diabetes, but not in control individuals, plasma EV PD-L1 positively correlated with circulating C-peptide, suggesting that higher EV PD-L1 could be protective for residual beta cell function. IFN exposure increases PD-L1 on the beta cell EV surface. Beta cell EV PD-L1 binds PD1 and inhibits CD8+ T cell proliferation and cytotoxicity. Circulating EV PD-L1 is higher in Ab+ individuals than in control individuals. Circulating EV PD-L1 levels correlate with residual C-peptide at different stages in type 1 diabetes progression. These findings suggest that EV PD-L1 could contribute to heterogeneity in type 1 diabetes progression and residual beta cell function and raise the possibility that EV PD-L1 could be exploited as a means to inhibit immune-mediated beta cell death.

Quantitative analysis of islet prohormone convertase 1/3 expression in human pancreas donors with diabetes.

Islet prohormone-processing enzymes convert peptide hormone precursors to mature hormones. Defective beta cell prohormone processing and the release of incompletely processed peptide hormones are observed prior to the onset of diabetes, yet molecular mechanisms underlying impaired prohormone processing during the development of diabetes remains largely unknown. Previous studies have shown that prohormone convertase 1/3 (PC1/3) protein and mRNA expression levels are reduced in whole islets from donors with type 1 diabetes, although whether PC1/3-mediated prohormone processing in alpha and beta cells is disrupted in type 1 diabetes remained to be explored. Herein, we aimed to analyse the expression of PC1/3 in islets from non-diabetic donors, autoantibody-positive donors and donors diagnosed with type 1 diabetes or type 2 diabetes. Immunostaining and high-dimensional image analysis were performed on pancreatic sections from a cross-sectional cohort of 54 donors obtained from the Network for Pancreatic Organ Donors with Diabetes (nPOD) repository, to evaluate PC1/3 expression patterns in islet alpha, beta and delta cells at different stages of diabetes. Alpha and beta cell morphology were altered in donors with type 1 diabetes, including decreased alpha and beta cell size. As expected, the insulin-positive and PC1/3-positive areas in the islets were both reduced, and this was accompanied by a reduced percentage of PC1/3-positive and insulin-positive/PC1/3-positive cells in islets. PC1/3 and insulin co-localisation was also reduced. The glucagon-positive area, as well as the percentage of glucagon-positive and glucagon-positive/PC1/3-positive cells in islets, was increased. PC1/3 and glucagon co-localisation was also increased in donors with type 1 diabetes. The somatostatin-positive cell area and somatostatin staining intensity were elevated in islets from donors with recent-onset type 1 diabetes. Our high-resolution histomorphological analysis of human pancreatic islets from donors with and without diabetes has uncovered details of the cellular origin of islet prohormone peptide processing defects. Reduced beta cell PC1/3 and increased alpha cell PC1/3 in islets from donors with type 1 diabetes pinpointed the functional deterioration of beta cells and the concomitant potential increase in PC1/3 usage for prohormone processing in alpha cells during the pathogenesis of type 1 diabetes. Our finding of PC1/3 loss in beta cells may inform the discovery of new prohormone biomarkers as indicators of beta cell dysfunction, and the finding of elevated PC1/3 expression in alpha cells may encourage the design of therapeutic targets via leveraging alpha cell adaptation in diabetes.

The signature of serum lipids remodeling in recent-onset type 2 diabetes mellitus treated with dulaglutide and liraglutide

The signature of serum lipids remodeling in recent-onset type 2 diabetes mellitus treated with dulaglutide and liraglutide

Beta cell extracellular vesicle PD-L1 as a novel regulator of CD8+ T cell activity and biomarker during the evolution of Type 1 Diabetes.

Surviving beta cells in type 1 diabetes respond to inflammation by upregulating programmed death-ligand 1 (PD-L1) to engage immune cell programmed death-1 (PD-1) and limit destruction by self-reactive immune cells. Extracellular vesicles (EVs) and their cargo can serve as biomarkers of beta cell health and contribute to islet intercellular communication. We hypothesized that the inflammatory milieu of type 1 diabetes increases PD-L1 in beta cell EV cargo and that EV PD-L1 may protect beta cells against immune-mediated cell death. Beta cell lines and human islets were treated with proinflammatory cytokines to model the proinflammatory type 1 diabetes microenvironment. EVs were isolated using ultracentrifugation or size exclusion chromatography and analysed via immunoblot, flow cytometry, and ELISA. EV PD-L1: PD-1 binding was assessed using a competitive binding assay and in vitro functional assays testing the ability of EV PD-L1 to inhibit NOD CD8 T cells. Plasma EV and soluble PD-L1 were assayed in plasma of individuals with islet autoantibody positivity (Ab+) or recent-onset type 1 diabetes and compared to non-diabetic controls. PD-L1 protein colocalized with tetraspanin-associated proteins intracellularly and was detected on the surface of beta cell EVs. 24-h IFN-α or IFN-γ treatment induced a two-fold increase in EV PD-L1 cargo without a corresponding increase in number of EVs. IFN exposure predominantly increased PD-L1 expression on the surface of beta cell EVs and beta cell EV PD-L1 showed a dose-dependent capacity to bind PD-1. Functional experiments demonstrated specific effects of beta cell EV PD-L1 to suppress proliferation and cytotoxicity of murine CD8 T cells. Plasma EV PD-L1 levels were increased in islet Ab+ individuals, particularly in those with single Ab+, Additionally, in from individuals with either Ab+ or type 1 diabetes, but not in controls, plasma EV PD-L1 positively correlated with circulating C-peptide, suggesting that higher EV-PD-L1 could be protective for residual beta cell function. IFN exposure increases PD-L1 on the beta cell EV surface. Beta cell EV PD-L1 binds PD1 and inhibits CD8 T cell proliferation and cytotoxicity. Circulating EV PD-L1 is higher in islet autoantibody positive patients compared to controls. Circulating EV PD-L1 levels correlate with residual C-peptide at different stages in type 1 diabetes progression. These findings suggest that EV PD-L1 could contribute to heterogeneity in type 1 diabetes progression and residual beta cell function and raise the possibility that EV PD-L1 could be exploited as a means to inhibit immune-mediated beta cell death.

Very-low-calorie diet-based intensive lifestyle intervention for remission of type 2 diabetes: Real-world experience in a South Asian population.

Very low-calorie diet (VLCD) can induce weight loss and diabetes remission (DR) amongst people with obesity and recent-onset type 2 diabetes (T2D). We aimed to determine the effectiveness and acceptability of VLCD in achieving DR amongst Sri Lankan adults with T2D. A retrospective analysis was conducted in a diabetes practice where VLCD-based Diabetes Remission Programme (VDRP) was offered for adults (>18 years) with T2D for <3 years and body mass index over 25 kg/m2. VLCD (~800 kcal/day, provided with/without diet replacement formula) was offered for 8-12 weeks, followed by gradual food reintroduction and exercise. DR was defined as HbA1c <6.5% at least 3 months after stopping glucose-lowering medications. A total of 170 participants who enrolled in the VDRP (mean age 38.4 years [±11.1], men 68%, mean baseline HbA1c 86.9 [±18.1] mmol/mol (10.1 [±2.1]%), median duration of T2D 2 years [IQR 1-2]) and 87 (51%) of them followed the programme (attended at least one follow-up visit). Amongst the individuals who followed the VDRP, 40.2% achieved DR (35/87), compared with 2.4% (2/83) amongst those who did not follow the VDRP (aHR 9.3, 95% CI 2.2-16.4, p = 0.002). The proportion achieving normoglycaemia (HbA1c < 6.5%) but continued to take glucose-lowering medication was 20/87 among VDRP followers and 20/85 amongst VDRP non-followers. The commonest reasons for not following the VDRP were too restrictive dietary quantity (92%) and difficulties in finding recommended food items (67%). Majority (79%) would recommend VDRP to others. VDRP is effective in achieving T2D remission amongst Sri Lankan adults with recently diagnosed T2D and obesity. Over half of the participants followed the programme and over 75% would recommend it to others, indicating good acceptability.

Adherence to the Dietary Approaches to Stop Hypertension (DASH) diet is associated with lower visceral and hepatic lipid content in recent-onset type 1 diabetes and type 2 diabetes.

To investigate the associations of the Dietary Approaches to Stop Hypertension (DASH) score with subcutaneous (SAT) and visceral (VAT) adipose tissue volume and hepatic lipid content (HLC) in people with diabetes and to examine whether changes in the DASH diet were associated with changes in these outcomes. In total, 335 participants with recent-onset type 1 diabetes (T1D) and type 2 diabetes (T2D) from the German Diabetes Study were included in the cross-sectional analysis, and 111 participants in the analysis of changes during the 5-year follow-up. Associations between the DASH score and VAT, SAT and HLC and their changes were investigated using multivariable linear regression models by diabetes type. The proportion mediated by changes in potential mediators was determined using mediation analysis. A higher baseline DASH score was associated with lower HLC, especially in people with T2D (per 5 points: -1.5% [-2.7%; -0.3%]). Over 5 years, a 5-point increase in the DASH score was associated with decreased VAT in people with T2D (-514 [-800; -228] cm3). Similar, but imprecise, associations were observed for VAT changes in people with T1D (-403 [-861; 55] cm3) and for HLC in people with T2D (-1.3% [-2.8%; 0.3%]). Body mass index and waist circumference changes explained 8%-48% of the associations between DASH and VAT changes in both groups. In people with T2D, adipose tissue insulin resistance index (Adipo-IR) changes explained 47% of the association between DASH and HLC changes. A shift to a DASH-like diet was associated with favourable VAT and HLC changes, which were partly explained by changes in anthropometric measures and Adipo-IR.

Latest advancements in the development of new therapies for type 1 diabetes.

This study aims to explore new treatments for type 1 diabetes that could serve as an alternative or adjunct to insulin therapy. This is aliterature review based on asearch of relevant scientific articles in PubMed, Scopus, Google Scholar, and Cochrane Library databases. The scrutiny of publications revealed that the introduction of glucagon-like peptide-1 agonists into insulin therapy can improve disease control and reduce the frequency of hypoglycaemic episodes. While immune therapy is pathogenetically justified, its utility is limited in patients with recent onset of type 1 diabetes. It may, however, find application in prophylaxis in individuals at increased risk of developing this type of diabetes. Concurrently, stem cell therapy is under active investigation in clinical trials and has shown promise in reducing insulin dependence, improving β-cell function and controlling glucose levels. In addition, stem cells have demonstrated efficacy in treating complications of diabetes such as diabetic nephropathy, peripheral neuropathy and diabetic angiopathy. There is compelling evidence supporting the significant potential of gene-editing technology. Intravenous administration of T-regulatory cells, as one method of cell therapy, shows potential in stabilising the course of diabetes and slowing its progression. However, further research is warranted to confirm efficacy. While gene therapy holds promise, much of its research is currently in the preclinical stage. Further development of innovative therapies for type 1 diabetes has the potential to enhance the quality of life of patients, improve disease control and prevent the development of complications (Fig. 1, Ref. 54). Keywords: diabetes type 1, treatment, cell therapy, insulin, pancreatic β-cells.

Regulation of STAT1 Signaling in Human Pancreatic β-Cells by the Lysine Deacetylase HDAC6: A New Therapeutic Opportunity in Type 1 Diabetes?

Type 1 diabetes arises from the selective destruction of pancreatic β-cells by autoimmune mechanisms and intracellular pathways driven by Janus (JAK)-kinase mediated STAT isoforms (especially STAT1 & STAT2) are implicated as mediators of β-cell demise. Despite this, the molecular mechanisms that regulate JAK-STAT signalling in β-cells during the autoimmune attack remain only partially disclosed and the factors acting to antagonise pro-inflammatory STAT1 signalling are uncertain. We have recently implicated Signal Regulatory Protein (SIRP)-α in promoting β-cell viability in the face of ongoing islet autoimmunity and now reveal that this protein controls the availability of a cytosolic lysine deacetylase, HDAC6, whose activity regulates the phosphorylation and activation of STAT1. We provide evidence that STAT1 serves as a substrate for HDAC6 in β-cells and that sequestration of HDAC6 by SIRPα in response to anti-inflammatory cytokines (such as interleukin-13) leads to increased STAT1 acetylation. This then impairs the ability of STAT1 to promote gene transcription in response to pro-inflammatory cytokines including interferon-gamma (IFNγ). We further find that SIRPα is lost from the β-cells of subjects with recent-onset type 1 diabetes under conditions when HDAC6 is retained and STAT1 levels are increased. On this basis, we report a previously unrecognised role for cytokine-induced regulation of STAT1 acetylation in the control of β- cell viability and propose that targeted inhibition of HDAC6 activity may represent a novel therapeutic modality to promote β-cell viability in the face of active islet autoimmunity.

Gut microbiome shifts in people with type 1 diabetes are associated with glycaemic control: an INNODIA study.

The gut microbiome is implicated in the disease process leading to clinical type 1 diabetes, but less is known about potential changes in the gut microbiome after the diagnosis of type 1 diabetes and implications in glucose homeostasis. We aimed to analyse potential associations between the gut microbiome composition and clinical and laboratory data during a 2 year follow-up of people with newly diagnosed type 1 diabetes, recruited to the Innovative approaches to understanding and arresting type 1 diabetes (INNODIA) study. In addition, we analysed the microbiome composition in initially unaffected family members, who progressed to clinical type 1 diabetes during or after their follow-up for 4 years. We characterised the gut microbiome composition of 98 individuals with newly diagnosed type 1 diabetes (ND cohort) and 194 autoantibody-positive unaffected family members (UFM cohort), representing a subgroup of the INNODIA Natural History Study, using metagenomic sequencing. Participants from the ND cohort attended study visits within 6 weeks from the diagnosis and 3, 6, 12 and 24 months later for stool sample collection and laboratory tests (HbA1c, C-peptide, diabetes-associated autoantibodies). Participants from the UFM cohort were assessed at baseline and 6, 12, 18, 24 and 36 months later. We observed a longitudinal increase in 21 bacterial species in the ND cohort but not in the UFM cohort. The relative abundance of Faecalibacterium prausnitzii was inversely associated with the HbA1c levels at diagnosis (p=0.0019). The rate of the subsequent disease progression in the ND cohort, as assessed by change in HbA1c, C-peptide levels and insulin dose, was associated with the abundance of several bacterial species. Individuals with rapid decrease in C-peptide levels in the ND cohort had the lowest gut microbiome diversity. Nineteen individuals who were diagnosed with type 1 diabetes in the UFM cohort had increased abundance of Sutterella sp. KLE1602 compared with the undiagnosed UFM individuals (p=1.2 × 10-4). Our data revealed associations between the gut microbiome composition and the disease progression in individuals with recent-onset type 1 diabetes. Future mechanistic studies as well as animal studies and human trials are needed to further validate the significance and causality of these associations.

INfluenza VaccInation To mitigate typE 1 Diabetes (INVITED): a study protocol for a randomised, double-blind, placebo-controlled clinical trial in children and adolescents with recent-onset type 1 diabetes

IntroductionChildren and adolescents with recent-onset type 1 diabetes (T1D) commonly maintain a certain level of insulin production during the remission phase, which can last months to years. Preserving β-cell function...

A set of circulating microRNAs belonging to the 14q32 chromosome locus identifies two subgroups of individuals with recent-onset type 1 diabetes

Circulating microRNAs (miRNAs) are linked to the onset and progression of type 1 diabetes mellitus (T1DM), thus representing potential disease biomarkers. In this study, we employed a multiplatform sequencing approach to analyze circulating miRNAs in an extended cohort of prospectively evaluated recent-onset T1DM individuals from the INNODIA consortium. Our findings reveal that a set of miRNAs located within T1DM susceptibility chromosomal locus 14q32 distinguishes two subgroups of individuals. To validate our results, we conducted additional analyses on a second cohort of T1DM individuals, confirming the identification of these subgroups, which we have named cluster A and cluster B. Remarkably, cluster B T1DM individuals, who exhibit increased expression of a set of 14q32 miRNAs, show better glycemic control and display a different blood immunomics profile. Our findings suggest that this set of circulating miRNAs can identify two different T1DM subgroups with distinct blood immunomics at baseline and clinical outcomes during follow-up.

Early Metabolic Endpoints Identify Persistent Treatment Efficacy in Recent-Onset Type 1 Diabetes Immunotherapy Trials.

Mixed-meal tolerance test-stimulated area under the curve (AUC) C-peptide at 12-24 months represents the primary end point for nearly all intervention trials seeking to preserve β-cell function in recent-onset type 1 diabetes. We hypothesized that participant benefit might be detected earlier and predict outcomes at 12 months posttherapy. Such findings would support shorter trials to establish initial efficacy. We examined data from six Type 1 Diabetes TrialNet immunotherapy randomized controlled trials in a post hoc analysis and included additional stimulated metabolic indices beyond C-peptide AUC. We partitioned the analysis into successful and unsuccessful trials and analyzed the data both in the aggregate as well as individually for each trial. Among trials meeting their primary end point, we identified a treatment effect at 3 and 6 months when using C-peptide AUC (P = 0.030 and P < 0.001, respectively) as a dynamic measure (i.e., change from baseline). Importantly, no such difference was seen in the unsuccessful trials. The use of C-peptide AUC as a 6-month dynamic measure not only detected treatment efficacy but also suggested long-term C-peptide preservation (R2 for 12-month C-peptide AUC adjusted for age and baseline value was 0.80, P < 0.001), and this finding supported the concept of smaller trial sizes down to 54 participants. Early dynamic measures can identify a treatment effect among successful immune therapies in type 1 diabetes trials with good long-term prediction and practical sample size over a 6-month period. While external validation of these findings is required, strong rationale and data exist in support of shortening early-phase clinical trials.

A novel subpopulation of monocytes with a strong interferon signature indicated by SIGLEC-1 is present in patients with in recent-onset type 1 diabetes.

Type 1 diabetes is a T cell-mediated autoimmune disease characterised by pancreatic beta cell destruction. In this study, we explored the pathogenic immune responses in initiation of type 1 diabetes and new immunological targets for type 1 diabetes prevention and treatment. We obtained peripheral blood samples from four individuals with newly diagnosed latent autoimmune diabetes in adults (LADA) and from four healthy control participants. Single-cell RNA-sequencing (scRNA-seq) was performed on peripheral blood mononuclear cells to uncover transcriptomic profiles of early LADA. Validation was performed through flow cytometry in a cohort comprising 54 LADA, 17 adult-onset type 2 diabetes, and 26 healthy adults, matched using propensity score matching (PSM) based on age and sex. A similar PSM method matched 15 paediatric type 1 diabetes patients with 15 healthy children. Further flow cytometry analysis was performed in both peripheral blood and pancreatic tissues of non-obese diabetic (NOD) mice. Additionally, cell adoptive transfer and clearance assays were performed in NOD mice to explore the role of this monocyte subset in islet inflammation and onset of type 1 diabetes. The scRNA-seq data showed that upregulated genes in peripheral T cells and monocytes from early-onset LADA patients were primarily enriched in the IFN signalling pathway. A new cluster of classical monocytes (cluster4) was identified, and the proportion of this cluster was significantly increased in individuals with LADA compared with healthy control individuals (11.93% vs 5.93%, p=0.017) and that exhibited a strong IFN signature marked by SIGLEC-1 (encoding sialoadhesin). These SIGLEC-1+ monocytes expressed high levels of genes encoding C-C chemokine receptors 1 or 2, as well as genes for chemoattractants for T cells and natural killer cells. They also showed relatively low levels of genes for co-stimulatory and HLA molecules. Flow cytometry analysis verified the elevated levels of SIGLEC-1+ monocytes in the peripheral blood of participants with LADA and paediatric type 1 diabetes compared with healthy control participants and those with type 2 diabetes. Interestingly, the proportion of SIGLEC-1+ monocytes positively correlated with disease activity and negatively with disease duration in the LADA patients. In NOD mice, the proportion of SIGLEC-1+ monocytes in the peripheral blood was highest at the age of 6 weeks (16.88%), while the peak occurred at 12 weeks in pancreatic tissues (23.65%). Adoptive transfer experiments revealed a significant acceleration in diabetes onset in the SIGLEC-1+ group compared with the SIGLEC-1- or saline control group. Our study identified a novel group of SIGLEC-1+ monocytes that may serve as an important indicator for early diagnosis, activity assessment and monitoring of therapeutic efficacy in type 1 diabetes, and may also be a novel target for preventing and treating type 1 diabetes. RNA-seq data have been deposited in the GSA human database ( https://ngdc.cncb.ac.cn/gsa-human/ ) under accession number HRA003649.

Translation of a Diabetes Remission Service into Australian Primary Care: Findings from the Evaluation of DiRECT-Australia.

The Diabetes Remission Clinical Trial (DiRECT) study demonstrated that an intensive and structured weight management program in UK primary care resulted in high rates of diabetes remission in adults with recent onset type 2 diabetes mellitus (T2DM). This study was aimed at evaluating the translation of the DiRECT intervention into an Australian primary care setting. All patients enrolled in the DiRECT-Australia Type 2 Diabetes Remission Service in a region of Sydney (Macarthur region, South Western Sydney, Australia) were included. Eligible participants were aged 20-70 years, noninsulin treated, with T2DM of ≤6 years' duration, and body mass index (BMI) ≥ 27 kg/m2. Total diet replacement of 825-853 kcal/day using meal replacements was implemented for 12 weeks, followed by an ongoing structured program until 52 weeks, with regular follow-up with a general practitioner, dietitian, and/or practice nurse. Of 39 recruited participants, 32 (82.1%) and 27 (69.2%) completed 12 weeks and 52 weeks of the structured program, respectively. Decrease in weight by -12.0 kg (95% CI: -9.6, -14.4; p < 0.001) and -9.1 kg (95% CI: -5.2, -12.9; p < 0.001) and decrease in glycated haemoglobin (HbA1c) by -1.1% (95% CI: -0.6, -1.6; p < 0.001) and -0.6% (95% CI: -0.1, -1.1; p = 0.013) were observed at 12 and 52 weeks, respectively. At the end of 12 and 52 weeks, 93.8% (30/32) and 55.6% (15/27) of those with follow-up data met the criteria for diabetes remission, respectively. Quality of life and wellbeing scores increased over the course of 12 weeks, remaining significantly higher at 52 weeks. Participants reported they would be willing to pay A$92.50 (95% CI: A$75.80, A$109.30) per fortnight for the low-calorie meal replacement shakes. These findings support the feasibility of a structured diabetes remission service in an Australian primary care setting to achieve improvements in glycaemia, weight, and quality of life and wellbeing, and suggest a substantial willingness to pay for diet replacement products among participants.

A qualitative study of the perceptions and experiences of participants and healthcare professionals in the DiRECT-Australia type 2 diabetes remission service.

The UK Diabetes Remission Clinical Trial (DiRECT) study was replicated in an Australian primary care setting. This qualitative study aimed to explore and understand the perceptions and experiences of both participants and healthcare professionals (HCPs) involved in the DiRECT-Australia Type 2 Diabetes Remission Service. All participants and HCPs delivering the service were invited to participate in semi-structured interviews via online videoconferencing. The interview guides explored perceptions and experiences in DiRECT-Australia, covering aspects such as barriers and facilitators to recruitment and participation, motivations and challenges across service phases, adequacy of support provided and the overall acceptability of the service. All interviews were audio-recorded, transcribed verbatim and analysed using thematic analysis. Eight DiRECT-Australia participants and six HCPs (three general practitioners, two practice nurses and one dietitian) participated. Four overarching themes were identified: (1) Enablers and barriers to recruitment and continuous participation in DiRECT-Australia; (2) Motivators and overcoming barriers across the total diet replacement, food reintroduction and weight maintenance phases; (3) Importance of participant-HCP interactions and continuous support; (4) Acceptance and long-term need for DiRECT-Australia. Adherence to total diet replacement was less challenging than anticipated by participants. Transitioning to the food reintroduction phase was difficult but overcome through HCP support. DiRECT-Australia was well accepted by both participants and HCPs, and participants expressed willingness to continue with the service, if provided on a long-term basis. Both participants and HCPs were highly interested in the new diabetes remission service set up in an Australian primary care setting. The acceptability of DiRECT-Australia was underscored by participants emphasising the effectiveness of the service in achieving significant weight loss and diabetes remission. There is a need for long-term and wider implementation of the service to ensure that anyone with recent onset type 2 diabetes is offered the best possible chance to achieve remission.

The N-Methyl-D-Aspartate Receptor Antagonist Dextromethorphan Improves Glucose Homeostasis and Preserves Pancreatic Islets in NOD Mice.

For treatment of type 1 diabetes mellitus, a combination of immune-based interventions and medication to promote beta-cell survival and proliferation has been proposed. Dextromethorphan (DXM) is an N-methyl-D-aspartate receptor antagonist with a good safety profile, and to date, preclinical and clinical evidence for blood glucose-lowering and islet-cell-protective effects of DXM have only been provided for animals and individuals with type 2 diabetes mellitus. Here, we assessed the potential anti-diabetic effects of DXM in the non-obese diabetic mouse model of type 1 diabetes. More specifically, we showed that DXM treatment led to five-fold higher numbers of pancreatic islets and more than two-fold larger alpha- and beta-cell areas compared to untreated mice. Further, DXM treatment improved glucose homeostasis and reduced diabetes incidence by 50%. Our data highlight DXM as a novel candidate for adjunct treatment of preclinical or recent-onset type 1 diabetes.

Genetic engineering of regulatory T cells for treatment of autoimmune disorders including type 1 diabetes.

Suppression of pathogenic immune responses is a major goal in the prevention and treatment of type 1 diabetes. Adoptive cell therapy using regulatory T cells (Tregs), a naturally suppressive immune subset that is often dysfunctional in type 1 diabetes, is a promising approach to achieving localised and specific immune suppression in the pancreas or site of islet transplant. However, clinical trials testing administration of polyclonal Tregs in recent-onset type 1 diabetes have observed limited efficacy despite an excellent safety profile. Several barriers to efficacy have been identified, including lack of antigen specificity, low cell persistence post-administration and difficulty in generating sufficient cell numbers. Fortunately, the emergence of advanced gene editing techniques has opened the door to new strategies to engineer Tregs with improved specificity and function. These strategies include the engineering of FOXP3 expression to produce a larger source of suppressive cells for infusion, expressing T cell receptors or chimeric antigen receptors to generate antigen-specific Tregs and improving Treg survival by targeting cytokine pathways. Although these approaches are being applied in a variety of autoimmune and transplant contexts, type 1 diabetes presents unique opportunities and challenges for the genetic engineering of Tregs for adoptive cell therapy. Here we discuss the role of Tregs in type 1 diabetes pathogenesis and the application of Treg engineering in the context of type 1 diabetes.

Improved Specificity of Glutamate Decarboxylase 65 Autoantibody Measurement Using Luciferase-Based Immunoprecipitation System Assays.

Autoantibodies to glutamate decarboxylase (GADA) are widely used in the prediction and classification of type 1 diabetes. GADA radiobinding assays (RBAs) using N-terminally truncated antigens offer improved specificity but radioisotopes limit the high-throughput potential for population screening. Luciferase-based Immunoprecipitation System (LIPS) assays are sensitive and specific alternatives to RBAs with the potential to improve risk stratification. The performance of assays using the Luciferase (Nluc-) conjugated GAD65 constructs, Nluc-GAD65(96-585) and full length Nluc-GAD65(1-585) were evaluated in 434 well-characterised sera from recent-onset type 1 diabetes patients and first-degree relatives. Non-radioactive, high-throughput LIPS assays are quicker and require less serum than RBAs. Of 171 relatives previously tested single autoantibody positive for autoantibodies to full-length GAD65 by RBA but had not progressed to diabetes, fewer retested positive by LIPS using either truncated (n=72) or full-length (n=111) antigen. The Nluc-GAD65(96-585) truncation demonstrated the highest specificity in LIPS assays overall but in contrast to RBA, N-terminus truncations did not result in a significant increase in disease-specificity compared with the full-length antigen. This suggests that binding of non-specific antibodies is affected by the conformational changes resulting from addition of the Nluc antigen. Nluc-GAD65(96-585) LIPS assays offer low blood volume, high specificity GADA tests for screening and diagnostics.

Progression of type 1 diabetes is associated with high levels of soluble PD-1 in islet autoantibody-positive children

Aims/hypothesisType 1 diabetes is an autoimmune disorder that is characterised by destruction of pancreatic beta cells by autoreactive T lymphocytes. Although islet autoantibodies (AAb) are an indicator of disease progression, specific immune biomarkers that can be used as target molecules to halt development of type 1 diabetes have not been discovered. Soluble immune checkpoint molecules (sICM) play a pivotal role in counteracting excessive lymphocyte responses, but their role in type 1 diabetes is unexplored. In this longitudinal study, we measured sICM levels in AAb-positive (AAb+) children to identify molecules related to type 1 diabetes progression.MethodsWe measured the levels of 14 sICM in the sera of AAb+ children (n=57) compared to those with recent-onset type 1 diabetes (n=79) and healthy children (n=44), obtained from two cohorts. AAb+ children were followed up and divided based on their progression to type 1 diabetes (AAbP) or not (AAbNP) (if they lost islet autoimmunity and did not develop disease in subsequent years). sICM were also measured in the sample taken at the visit closest to disease onset in AAbP children.ResultsWe found that AAb+ children had a distinct sICM profile compared with healthy children and those with recent-onset type 1 diabetes. In addition, AAb+ children who progressed to type 1 diabetes (AAbP) had higher sICM concentrations than non-progressors (AAbNP). Further, sICM levels decreased in AAbP children close to disease onset. Application of Cox regression models highlighted that high concentrations of soluble programmed cell death protein 1 (sPD-1) are associated with type 1 diabetes progression (HR 1.71; 95% CI 1.16, 2.51; p=0.007).Conclusions/interpretationThis study reveals an sICM profile that is dysregulated during the preclinical stage of type 1 diabetes, and identifies sPD-1 as a pathophysiologically-relevant molecule that is associated with disease progression, offering a potential target for early interventions in autoimmune diabetes.Graphical

Analysis of type 2 diabetes heterogeneity with a tree-like representation: insights from the prospective German Diabetes Study and the LURIC cohort

Heterogeneity in type 2 diabetes can be represented by a tree-like graph structure by use of reversed graph-embedded dimensionality reduction. We aimed to examine whether this approach can be used to stratify key pathophysiological components and diabetes-related complications during longitudinal follow-up of individuals with recent-onset type 2 diabetes. For this cohort analysis, 927 participants aged 18-69 years from the German Diabetes Study (GDS) with recent-onset type 2 diabetes were mapped onto a previously developed two-dimensional tree based on nine simple clinical and laboratory variables, residualised for age and sex. Insulin sensitivity was assessed by a hyperinsulinaemic-euglycaemic clamp, insulin secretion was assessed by intravenous glucose tolerance test, hepatic lipid content was assessed by 1 H magnetic resonance spectroscopy, serum interleukin (IL)-6 and IL-18 were assessed by ELISA, and peripheral and autonomic neuropathy were assessed by functional and clinical measures. Participants were followed up for up to 16 years. We also investigated heart failure and all-cause mortality in 794 individuals with type 2 diabetes undergoing invasive coronary diagnostics from the Ludwigshafen Risk and Cardiovascular Health (LURIC) cohort. There were gradients of clamp-measured insulin sensitivity (both dimensions: p<0·0001) and insulin secretion (pdim1<0·0001, pdim2=0·00097) across the tree. Individuals in the region with the lowest insulin sensitivity had the highest hepatic lipid content (n=205, pdim1<0·0001, pdim2=0·037), pro-inflammatory biomarkers (IL-6: n=348, pdim1<0·0001, pdim2=0·013; IL-18: n=350, pdim1<0·0001, pdim2=0·38), and elevated cardiovascular risk (nevents=143, pdim1=0·14, pdim2<0·00081), whereas individuals positioned in the branch with the lowest insulin secretion were more prone to require insulin therapy (nevents=85, pdim1=0·032, pdim2=0·12) and had the highest risk of diabetic sensorimotor polyneuropathy (nevents=184, pdim1=0·012, pdim2=0·044) and cardiac autonomic neuropathy (nevents=118, pdim1=0·0094, pdim2=0·06). In the LURIC cohort, all-cause mortality was highest in the tree branch showing insulin resistance (nevents=488, pdim1=0·12, pdim2=0·0032). Significant gradients differentiated individuals having heart failure with preserved ejection fraction from those who had heart failure with reduced ejection fraction. These data define the pathophysiological underpinnings of the tree structure, which has the potential to stratify diabetes-related complications on the basis of routinely available variables and thereby expand the toolbox of precision diabetes diagnosis. German Diabetes Center, German Federal Ministry of Health, Ministry of Culture and Science of the state of North Rhine-Westphalia, German Federal Ministry of Education and Research, German Diabetes Association, German Center for Diabetes Research, European Community, German Research Foundation, and Schmutzler Stiftung.