TCR+/BCR+ dual-expressing cells and their associated public BCR clonotype are not enriched in type 1 diabetes.

Ahmed and colleagues recently described a novel hybrid lymphocyte expressing both a B and T cell receptor, termed double expresser (DE) cells. DE cells in blood of type 1 diabetes (T1D) subjects were present at increased numbers and enriched for a public B cell clonotype. Here, we attempted to reproduce these findings. While we could identify DE cells by flow cytometry, we found no association between DE cell frequency and T1D status. We were unable to identify the reported public B cell clone, or any similar clone, in bulk B cells or sorted DE cells from T1D subjects or controls. We also did not observe increased usage of the public clone VH or DH genes in B cells or in sorted DE cells. Taken together, our findings suggest that DE cells and their alleged public clonotype are not enriched in T1D. This Matters Arising paper is in response to Ahmed et al. (2019), published in Cell. See also the response by Ahmed et al. (2021), published in this issue.

Potential contribution of gut microbiota in the development of autoantibodies in T1D children carrying HLA-DRB1/DQB1 risk alleles: an experimental and in silico analysis.

This study aimed to investigate the prevalence of insulin autoantibody (IAA), glutamic acid decarboxylase antibody (GADA), and insulinoma-associated antigen-2 antibody (IA-2A) in type 1 diabetes (T1D) children based on the presence of predisposing HLA-II alleles. Additionally, to assess the sequence homology between autoantigens of islet cells and selected proteins derived from gut bacteria in terms of their binding capacities to HLA risk alleles, HLA-DRB1/DQB1 alleles were determined by PCR-SSOP in 111 T1D children (probands) along with 222 parents and 133 siblings. Autoantibodies were measured by ELISA, and in silico analysis was run as follows: protein extraction, homology and epitope prediction, peptide alignment, and HLA-peptide docking. Higher significant frequencies of DRB1*03:01, DQB1*02:01, and DQB1*03:02 alleles and DRB1*03:01 ~ DQB1*02:01 haplotype and lower frequencies of DRB1*11:01, DRB1*14:01, and DQB1*03:01 alleles were found in probands compared to parents and siblings. DRB1*11:01 ~ DQB1*03:01, DRB1*14:01 ~ DQB1*05:03, and DRB1*15:01-DQB1*06:02 haplotypes were significantly less frequent in the probands compared to parents. Out of 111 probands, 21 were seronegative, 90 tested positive for one autoantibody, and 15 showed the concurrent presence of three autoantibodies. Logistic regression analysis revealed that DRB1*04 ~ DQB1*03:02 haplotype was associated with the induction of GADA and IA-2A, while DRB1*11:01 ~ DQB1*03:01 was associated with seronegativity. Epitopes derived from GAD and gut bacteria showed strong binding capacities to HLA risk alleles. Due to the sequence similarities between gut bacteria-derived proteins and islet cell autoantigens and their potential for binding to HLA risk alleles, dysbiosis of gut microbiota can be considered another risk factor for the development of T1D, especially in genetically susceptible individuals.

A functional variant rs912304 for late-onset T1D risk contributes to islet dysfunction by regulating proinflammatory cytokine-responsive gene STXBP6 expression.

BACKGROUND: Our previous genome­wide association studies (GWAS) have suggested rs912304 in 14q12 as a suggestive risk variant for type 1 diabetes (T1D). However, the association between this risk region and T1D subgroups and related clinical risk features, the underlying causal functional variant(s), putative candidate gene(s), and related mechanisms are yet to be elucidated. METHODS: We assessed the association between variant rs912304 and T1D, as well as islet autoimmunity and islet function, stratified by the diagnosed age of 12. We used epigenome bioinformatics analyses, dual luciferase reporter assays, and expression quantitative trait loci (eQTL) analyses to prioritize the most likely functional variant and potential causal gene. We also performed functional experiments to evaluate the role of the causal gene on islet function and its related mechanisms. RESULTS: We identified rs912304 as a risk variant for T1D subgroups with diagnosed age ≥ 12 but not < 12. This variant is associated with residual islet function but not islet-specific autoantibody positivity in T1D individuals. Bioinformatics analysis indicated that rs912304 is a functional variant exhibiting spatial overlaps with enhancer active histone marks (H3K27ac and H3K4me1) and open chromatin status (ATAC-seq) in the human pancreas and islet tissues. Luciferase reporter gene assays and eQTL analyses demonstrated that the biallelic sites of rs912304 had differential allele-specific enhancer activity in beta cell lines and regulated STXBP6 expression, which was defined as the most putative causal gene based on Open Targets Genetics, GTEx v8 and Tiger database. Moreover, Stxbp6 was upregulated by T1D-related proinflammatory cytokines but not high glucose/fat. Notably, Stxbp6 over-expressed INS-1E cells exhibited decreasing insulin secretion and increasing cell apoptosis through Glut1 and Gadd45ß, respectively. CONCLUSIONS: This study expanded the genomic landscape regarding late-onset T1D risk and supported islet function mechanistically connected to T1D pathogenesis.

Impact of socioeconomic status on chronic control and complications of type 1 diabetes mellitus in users of glucose flash systems: a follow-up study.

BACKGROUND: This study investigates the association between socioeconomic status (SES) and glycemic control in individuals with type 1 diabetes (T1D) using flash glucose monitoring (FGM) devices within a public health system where these technologies are freely available and utilized according to recommended guidelines. METHODS: A follow-up study of 1060 adults (mean age 47.4 ± 15.0 years, 49.0% women) with T1D, receiving care at three Spanish university hospitals that regularly employ the FGM system. SES was assessed using the Spanish Deprivation Index and the average annual net income per person. Glycemic data were collected over a 14-day follow-up period, including baseline glycated hemoglobin (HbA1c) levels prior to sensor placement, the last available HbA1c levels, and FGM-derived glucose metrics. Individuals with sensor usage time < 70% were excluded. Chronic micro and macrovascular complications related to diabetes were documented. Regression models, adjusted for clinical variables, were employed to determine the impact of SES on optimal sensor control (defined as time in range (TIR) ≥ 70% with time below range < 4%) and disease complications. RESULTS: The average follow-up was of 2 years. The mean TIR and the percentage of individuals with optimal control were higher in individuals in the highest SES quartile (64.9% ± 17.8% and 27.9%, respectively) compared to those in the lowest SES quartile (57.8 ± 17.4% and 12.1%) (p < 0.001). Regression models showed a higher risk of suboptimal control (OR 2.27, p < 0.001) and ischemic heart disease and/or stroke (OR 3.59, p = 0.005) in the lowest SES quartile. No association was observed between SES and the risk of diabetic nephropathy and retinopathy. FGM system improved HbA1c levels across all SES quartiles. Although individuals in the highest SES quartile still achieved a significantly lower value at the end of the follow-up 55 mmol/mol (7.2%) compared to those in the lowest SES quartile 60 mmol/mol (7.6%) (p < 0.001), the significant disparities in this parameter between the various SES groups were significantly reduced after FGM technology use. CONCLUSIONS: Socioeconomic status plays a significant role in glycemic control and complications in individuals with T1D, extending beyond access to technology and its proper utilization. The free utilization of FGM technology helps alleviate the impact of social inequalities on glycemic control.

Gene-expression profiling of laser-dissected islets and studies in deficient mice reveal chemokines as differential driving force of type 1 diabetes.

Although type 1 diabetes (T1D) results from the autoimmune destruction of the insulin-producing ß-cells, its treatment is largely restricted to exogenous insulin administration. Only few therapies targeting the autoaggressive immune system have been introduced into clinical practice or are considered in clinical trials. Here, we provide a gene expression profile of the islet microenvironment obtained by laser-dissection microscopy in an inducible mouse model. Thereby, we have identified novel targets for immune intervention. Increased gene expression of most inflammatory proteins was apparent at day 10 after T1D induction and largely paralleled the observed degree of insulitis. We further focused on genes involved in leukocyte migration, including chemokines and their receptors. Besides the critical chemokine CXCL10, we found several other chemokines upregulated locally in temporary or chronic manner. Localization of the chemokine ligand/receptor pairs to the islet microenvironment has been confirmed by RNAscope. Interference with the CXCL16-CXCR6 and CX3CL1-CX3CR1 axes, but not the CCL5-CCR1/3/5 axis, resulted in reduced insulitis and lower T1D incidence. Further, we found that the receptors for the differentially expressed chemokines CXCL10, CXCL16 and CX3CL1 are distributed unevenly among islet autoantigen-specific T cells, which explains why the interference with just one chemokine axis cannot completely abrogate insulitis and T1D.

T-cell immunity against Severe Acute Respiratory Syndrome Coronavirus 2 proteins in patients with type 1 diabetes.

AIMS: Individuals with type 1 diabetes (T1D) do not appear to have an elevated risk of severe Coronavirus Disease 19 (COVID-19). Pre-existing immune reactivity to Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) in unexposed individuals may serve as a protective factor. Hence, our study was designed to evaluate the existence of T cells with reactivity against SARS-CoV-2 antigens in unexposed patients with T1D. MATERIALS AND METHODS: Peripheral blood mononuclear cells (PBMCs) were collected from SARS-CoV-2 unexposed patients with T1D and healthy control subjects. SARS-CoV-2 specific T cells were identified in PBMCs by ex-vivo interferon (IFN)γ-ELISpot and flow cytometric assays. The epitope specificity of T cells in T1D was inferred through T Cell Receptor sequencing and GLIPH2 clustering analysis. RESULTS: T1D patients unexposed to SARS-CoV-2 exhibited higher rates of virus-specific T cells than controls. The T cells primarily responded to peptides from the ORF7/8, ORF3a, and nucleocapsid proteins. Nucleocapsid peptides predominantly indicated a CD4+ response, whereas ORF3a and ORF7/8 peptides elicited both CD4+ and CD8+ responses. The GLIPH2 clustering analysis of TCRß sequences suggested that TCRß clusters, associated with the autoantigens proinsulin and Zinc transporter 8 (ZnT-8), might share specificity towards ORF7b and ORF3a viral epitopes. Notably, PBMCs from three T1D patients exhibited T cell reactivity against both ORF7b/ORF3a viral epitopes and proinsulin/ZnT-8 autoantigens. CONCLUSIONS: The increased frequency of SAR-CoV-2- reactive T cells in T1D patients might protect against severe COVID-19 and overt infections. These results emphasise the long-standing association between viral infections and T1D.

Influence of sphingolipid enzymes on blood glucose levels, development of diabetes, and involvement of pericytes.

AIMS: Sulfatide is a chaperone for insulin manufacturing in beta cells. Here we explore whether the blood glucose values normally could be associated with this sphingolipid and especially two of its building enzymes CERS2 and CERS6. Both T1D and T2D have low blood sulfatide levels, and insulin resistance on beta cells at clinical diagnosis. Furthermore, we examined islet pericytes for sulfatide, and beta-cell receptors for GLP-1, both of which are related to the insulin production. MATERIALS AND METHODS: We examined mRNA levels in islets from the DiViD and nPOD studies, performed genetic association analyses, and histologically investigated pericytes in the islets for sulfatide. RESULTS: Polymorphisms of the gene encoding the CERS6 enzyme responsible for synthesising dihydroceramide, a precursor to sulfatide, are associated with random blood glucose values in non-diabetic persons. This fits well with our finding of sulfatide in pericytes in the islets, which regulates the capillary blood flow in the islets of Langerhans, which is important for oxygen supply to insulin production. In the islets of newly diagnosed T1D patients, we observed low levels of GLP-1 receptors; this may explain the insulin resistance in their beta cells and their low insulin production. In T2D patients, we identified associated polymorphisms in both CERS2 and CERS6. CONCLUSIONS: Here, we describe several polymorphisms in sulfatide enzymes related to blood glucose levels and HbA1c in non-diabetic individuals. Islet pericytes from such persons contain sulfatide. Furthermore, low insulin secretion in newly diagnosed T1D may be explained by beta-cell insulin resistance due to low levels of GLP-1 receptors.

Muscle-to-fat ratio in children and adolescents with type 1 diabetes in predicting glycaemic control and partial clinical remission.

BACKGROUND: Advances in treatment could mitigate the expected adverse changes in the body composition of children and adolescents with type 1 diabetes (T1D). OBJECTIVES: To examine the evolution of weight status and body composition and their association with glycaemic control and partial clinical remission in youth with T1D. METHODS: Ninety-nine participants with T1D (median age 9.5 years [interquartile range 7.3, 12.9], 59.6% boys) were longitudinally followed for 3 years since diagnosis. Data at seven pre-determined time points were extracted from medical files. Outcome measures included body mass index (BMI) z-scores, muscle-to-fat ratio (MFR) z-scores, haemoglobin A1c (HbA1c) levels, continuous glucose monitoring metrics, and insulin dose-adjusted HbA1c (IDAA1c) levels. RESULTS: The BMI z-scores increased significantly (p < 0.001) for both sexes, with no significant change in MFR z-scores over time. The girls had higher BMI z-scores (p < 0.001) and lower MFR z-scores than the boys (p = 0.016). The mean HbA1c levels decreased during the first month and at 3 months since diagnosis (p < 0.001), then plateaued and achieved a median overall HbA1c of 7.1% for the entire cohort. At 12 months, 37 participants (37.6%) were in partial clinical remission, as evidenced by IDAA1c ≤ 9. The odds of partial clinical remission at 2 years increased by 2.1-fold for each standard deviation increase in the MFR z-score (p < 0.001). Higher MFR z-scores were associated with better metabolic control. CONCLUSIONS: Integration of body composition assessments could mitigate adverse body changes in paediatric patients with T1D.

Genetic evidence for the causal association between type 1 diabetes and the risk of polycystic ovary syndrome.

BACKGROUND: Accumulating observational studies have identified associations between type 1 diabetes (T1D) and polycystic ovary syndrome (PCOS). Still, the evidence about the causal effect of this association is uncertain. METHODS: We performed a two-sample Mendelian randomization (MR) analysis to test for the causal association between T1D and PCOS using data from a large-scale biopsy-confirmed genome-wide association study (GWAS) in European ancestries. We innovatively divided T1D into nine subgroups to be analyzed separately, including: type1 diabetes wide definition, type1 diabetes early onset, type 1 diabetes with coma, type 1 diabetes with ketoacidosis, type 1 diabetes with neurological complications, type 1 diabetes with ophthalmic complications, type 1 diabetes with peripheral circulatory complications, type 1 diabetes with renal complications, and type 1 diabetes with other specified/multiple/unspecified complications. GWAS data for PCOS were obtained from a large-scale GWAS (10,074 cases and 103,164 controls) for primary analysis and the IEU consortium for replication and meta-analysis. Sensitivity analyses were conducted to evaluate heterogeneity and pleiotropy. RESULTS: Following rigorous instrument selection steps, the number of SNPs finally used for T1D nine subgroups varying from 6 to 36 was retained in MR estimation. However, we did not observe evidence of causal association between type 1 diabetes nine subgroups and PCOS using the IVW analysis, MR-Egger regression, and weighted median approaches, and all P values were > 0.05 with ORs near 1. Subsequent replicates and meta-analyses also yielded consistent results. A number of sensitivity analyses also did not reveal heterogeneity and pleiotropy, including Cochran's Q test, MR-Egger intercept test, MR-PRESSO global test, leave-one-out analysis, and funnel plot analysis. CONCLUSION: This is the first MR study to investigate the causal relationship between type 1 diabetes and PCOS. Our findings failed to find substantial causal effect of type 1 diabetes on risk of PCOS. Further randomized controlled studies and MR studies are necessary.

Invariant VD and DJ Motifs Define a Novel Class of Human Antibodies and TCRs Prototyped by antigen receptors of Dual-Expresser Lymphocytes.

INTRODUCTION: Dual-expressing lymphocytes (DEs) are unique immune cells that express both B cell receptors (BCRs, surface antibody) and T cell receptors (TCRs). In type 1 diabetes, DE antibodies are predominated by one antibody (x-mAb), an IgM monoclonal antibody with a germline-encoded CDR3 that recognizes self-reactive TCRs. We explored if x-mAb and its interacting TCRs have distinct structural features. METHODS: Using bioinformatics, we compared x-mAb and its most common interacting TCRαß to billions of antigen receptor sequences to determine if they were unique or randomly generated. RESULTS: X-mAb represents a unique class of human antibodies with a conserved CDR3 sequence (CARx1-4DTAMVYYFYDW), consisting of a fixed DJH motif (DTAMVYYFDYW) paired with various VH genes. A public TCRß clonotype (CASSPGTEAFF) associated with x-mAb on DEs features two invariant segments, VßD (CASSPGT) and DJß (PGTEAFF), key to two large families of public TCRß clonotypes-CASSPGT-Jßx and CASSPGT-Jßx-formed by recombining the VßD motif with Jß genes and the DJß motif with Vß genes. B cells also use CASSPGT as a VHD motif for public IGH clonotypes (CASSPGT-Jßx). DISCUSSION: DEs, unlike conventional T and B cells, use invariant motifs to create public antibodies and TCRs, a trait previously seen only in cartilaginous fish.

MiR-375: it could be a general biomarker of metabolic changes and inflammation in type 1 diabetes patients and their siblings.

PURPOSE: Type 1 diabetes (T1D) is a chronic autoimmune illness that results in loss of pancreatic beta cells and insulin insufficiency. MicroRNAs (miRNAs) are linked to immune system functions contributing to the pathophysiology of T1D, miRNA-375 is significantly expressed in the human pancreas and its circulatory levels might correspond to beta cell alterations. Pancreatic islet cell antibodies (ICA) and Glutamic acid decarboxylase antibodies (GADA) have roles in autoimmune pathogenesis and are predictive markers of T1D. The aim of this work was to detect serum level changes of miRNA-375, ICA, and GADA in T1D patients, and their siblings compared to healthy controls and correlate them with T1D biochemical parameters. METHODS: The study included 66 T1D patients (32 males and 34 females; age range 3-18 years), 22 patients' siblings (13 males and 9 females; age range 4-17 years), and 23 healthy controls (7 males and 16 females; age range 4-17 years). MiRNA-375 levels were measured using quantitative reverse transcription polymerase chain reaction (RT-qPCR), while ICA and GADA levels were measured using enzyme-linked immunosorbent assay (ELISA). Data analysis was done utilizing SPSS-17 software. RESULTS: MiR-375 levels were downregulated in T1D patients and further decreased in their siblings when compared to healthy controls. Furthermore, miR-375 exhibited inverse correlations with HbA1c levels but no correlations with Total Insulin Dose, disease duration, or autoantibodies (GADA & ICA). CONCLUSION: Our study indicates that miR-375 is significantly downregulated in children with T1D and their siblings, suggesting its potential role as a biomarker for beta-cell function and glycemic control.

Type 1 diabetes and inborn errors of immunity: Complete strangers or 2 sides of the same coin?

Type 1 diabetes (T1D) is a polygenic disease and does not follow a mendelian pattern. Inborn errors of immunity (IEIs), on the other hand, are caused by damaging germline variants, suggesting that T1D and IEIs have nothing in common. Some IEIs, resulting from mutations in genes regulating regulatory T-cell homeostasis, are associated with elevated incidence of T1D. The genetic spectrum of IEIs is gradually being unraveled; consequently, molecular pathways underlying human monogenic autoimmunity are being identified. There is an appreciable overlap between some of these pathways and the genetic variants that determine T1D susceptibility, suggesting that after all, IEI and T1D are 2 sides of the same coin. The study of monogenic IEIs with a variable incidence of T1D has the potential to provide crucial insights into the mechanisms leading to T1D. These insights contribute to the definition of T1D endotypes and explain disease heterogeneity. In this review, we discuss the interconnected pathogenic pathways of autoimmunity, ß-cell function, and primary immunodeficiency. We also examine the role of environmental factors in disease penetrance as well as the circumstantial evidence of IEI drugs in preventing and curing T1D in individuals with IEIs, suggesting the repositioning of these drugs also for T1D therapy.

Comparative Screening of the Liver Gene Expression Profiles from Type 1 and Type 2 Diabetes Rat Models.

Experimental animal models of diabetes can be useful for identifying novel targets related to disease, for understanding its physiopathology, and for evaluating emerging antidiabetic treatments. This study aimed to characterize two rat diabetes models: HFD + STZ, a high-fat diet (60% fat) combined with streptozotocin administration (STZ, 35 mg/kg BW), and a model with a single STZ dose (65 mg/kg BW) in comparison with healthy rats. HFD + STZ- induced animals demonstrated a stable hyperglycemia range (350-450 mg/dL), whereas in the STZ-induced rats, we found glucose concentration values with a greater dispersion, ranging from 270 to 510 mg/dL. Moreover, in the HFD + STZ group, the AUC value of the insulin tolerance test (ITT) was found to be remarkably augmented by 6.2-fold higher than in healthy animals (33,687.0 ± 1705.7 mg/dL/min vs. 5469.0 ± 267.6, respectively), indicating insulin resistance (IR). In contrast, a more moderate AUC value was observed in the STZ group (19,059.0 ± 3037.4 mg/dL/min) resulting in a value 2.5-fold higher than the average exhibited by the control group. After microarray experiments on liver tissue from all animals, we analyzed genes exhibiting a fold change value in gene expression <-2 or >2 (p-value <0.05). We found 27,686 differentially expressed genes (DEG), identified the top 10 DEGs and detected 849 coding genes that exhibited opposite expression patterns between both diabetes models (491 upregulated genes in the STZ model and 358 upregulated genes in HFD + STZ animals). Finally, we performed an enrichment analysis of the 849 selected genes. Whereas in the STZ model we found cellular pathways related to lipid biosynthesis and metabolism, in the HFD + STZ model we identified pathways related to immunometabolism. Some phenotypic differences observed in the models could be explained by transcriptomic results; however, further studies are needed to corroborate these findings. Our data confirm that the STZ and the HFD + STZ models are reliable experimental models for human T1D and T2D, respectively. These results also provide insight into alterations in the expression of specific liver genes and could be utilized in future studies focusing on diabetes complications associated with impaired liver function.

Inhomogeneous Magnetization Transfer (ihMT) imaging in the acute cuprizone mouse model of demyelination/remyelination.

BACKGROUND: To investigate the association of ihMT (inhom signals with the demyelination and remyelination phases of the acute cuprizone mouse model in comparison with histology, and to assess the extent of tissue damage and repair from MRI data. METHODS: Acute demyelination by feeding 0.2% cuprizone for five weeks, followed by a four-week remyelination period was applied on genetically modified plp-GFP mice. Animals were scanned at different time points of the demyelination and remyelination phases of the cuprizone model using a multimodal MRI protocol, including ihMT T1D-filters, MPF (Macromolecular Proton Fraction) and R1 (longitudinal relaxation rate). For histology, plp-GFP (proteolipid protein - Green Fluorescent Protein) microscopy and LFB (Luxol Fast Blue) staining were employed as references for the myelin content. Comparison of MRI with histology was performed in the medial corpus callosum (mCC) and cerebral cortex (CTX) at two brain levels whereas ROI-wise and voxel-based analyses of the MRI metrics allowed investigating in vivo the spatial extent of myelin alterations. RESULTS: IhMT high-pass T1D-filters, targeted toward long T1D components, showed significant temporal variations in the mCC consistent with the effects induced by the cuprizone toxin. In addition, the corresponding signals correlated strongly and significantly with the myelin content assessed by GFP fluorescence and LFB staining over the demyelination and the remyelination phases. The signal of the band-pass T1D-filter, which isolates short T1D components, showed changes over time that were poorly correlated with histology, hence suggesting a sensitivity to pathological processes possibly not related to myelin. Although MPF was also highly correlated to histology, ihMT high-pass T1D-filters showed better capability to characterize the spatial-temporal patterns during the demyelination and remyelination phases of the acute cuprizone model (e.g., rostro-caudal gradient of demyelination in the mCC previously described in the literature). CONCLUSIONS: IhMT sequences selective for long T1D components are specific and sensitive in vivo markers of demyelination and remyelination and have successfully captured the spatially heterogeneous pattern of the demyelination and remyelination mechanisms in the cuprizone model. Interestingly, differences in signal variations between the ihMT high-pass and band-pass T1D-filter, suggest a sensitivity of the ihMT sequences targeted to short T1Ds to alterations other than those of myelin. Future studies will need to further address these differences by examining more closely the origin of the short T1D components and the variation of each T1D component in pathology.

Type 1 diabetes in the pancreas: A histological perspective.

AIMS: This review aims to introduce research in the pancreas to a broader audience. The pancreas is a heterocrine gland residing deep within our abdominal cavity. It is the home to our islets, which play a pivotal role in regulating metabolic homeostasis. Due to its structure and location, it is an impossible organ to study, in molecular detail, in living humans, and yet, understanding the pancreas is critical if we aim to characterise the immunopathology of type 1 diabetes (T1D) and one day prevent the triggering of the autoimmune attack associated with ß-cell demise. METHODS: Over a 100 years ago, we began studying pancreatic histology using cadaveric samples and clever adaptations to microscopes. As histologists, some may say nothing much has changed. Nevertheless, our microscopes can now interrogate multiple proteins at molecular resolution. Images of pancreas sections are no longer constrained to a single field of view and can capture a thousands and thousands of cells. AI-image-analysis packages can analyse these massive data sets offering breakthrough findings. CONCLUSION: This narrative review will provide an overview of pancreatic anatomy, and the importance of research focused on the pancreas in T1D. It will range from histological breakthroughs to briefly discussing the challenges associated with characterising the organ. I shall briefly introduce a selection of the available global biobanks and touch on the distinct pancreatic endotypes that differ immunologically and in ß-cell behaviour. Finally, I will introduce the idea of developing a collaborative tool aimed at developing a cohesive framework for characterising heterogeneity and stratifying endotypes in T1D more readily.

Continuous glucose monitoring metrics (Mean Glucose, time above range and time in range) are superior to glycated haemoglobin for assessment of therapeutic efficacy.

AIM: To evaluate continuous glucose monitoring (CGM) metrics for use as alternatives to glycated haemoglobin (HbA1c) to evaluate therapeutic efficacy. METHODS: We re-analysed correlations among CGM metrics from studies involving 545 people with type 1 diabetes (T1D), 5910 people with type 2 diabetes (T2D) and 98 people with T1D during pregnancy and the postpartum period. RESULTS: Three CGM metrics, interstitial fluid Mean Glucose level, proportion of time above range (%TAR) and proportion of time in range (%TIR), were correlated with HbA1c and provided metrics that can be used to evaluate therapeutic efficacy. Mean Glucose showed the highest correlation with %TAR (r = 0.98 in T1D, 0.97 in T2D) but weaker correlations with %TIR (r = -0.92 in T1D, -0.83 in T2D) or with HbA1c (r = 0.78 in T1D). %TAR and %TIR were highly correlated (r = -0.96 in T1D, -0.91 in T2D). After 6 months of use of real-time CGM by people with T1D, changes in Mean Glucose level were more highly correlated with changes in %TAR (r = 0.95) than with changes in %TIR (r = -0.85) or with changes in HbA1c level (r = 0.52). These metrics can be combined with metrics of hypoglycaemia and/or glycaemic variability to provide a more comprehensive assessment of overall quality of glycaemic control. CONCLUSION: The CGM metrics %TAR and %TIR show much higher correlations with Mean Glucose than with HbA1c and provide sensitive indicators of efficacy. Mean glucose may be the best metric and shows consistently higher correlations with %TAR than with %TIR.

The effect of ambient ozone exposure on three types of diabetes: a meta-analysis.

BACKGROUND: Ozone as an air pollutant is gradually becoming a threat to people's health. However, the effect of ozone exposure on risk of developing diabetes, a fast-growing global metabolic disease, remains controversial. OBJECTIVE: To evaluate the impact of ambient ozone exposure on the incidence rate of type 1, type 2 and gestational diabetes mellitus. METHOD: We systematically searched PubMed, Web of Science, and Cochrane Library databases before July 9, 2022, to determine relevant literature. Data were extracted after quality evaluation according to the Newcastle Ottawa Scale (NOS) and the agency for healthcare research and quality (AHRQ) standards, and a meta-analysis was used to evaluate the correlation between ozone exposure and type 1 diabetes mellitus (T1D), type 2 diabetes mellitus (T2D), and gestational diabetes mellitus (GDM). The heterogeneity test, sensitivity analysis, and publication bias were performed using Stata 16.0. RESULTS: Our search identified 667 studies from three databases, 19 of which were included in our analysis after removing duplicate and ineligible studies. Among the remaining studies, three were on T1D, five were on T2D, and eleven were on GDM. The result showed that ozone exposure was positively correlated with T2D [effect size (ES) = 1.06, 95% CI: 1.02, 1.11] and GDM [pooled odds ratio (OR) = 1.01, 95% CI: 1.00, 1.03]. Subgroup analysis demonstrated that ozone exposure in the first trimester of pregnancy might raise the risk of GDM. However, no significant association was observed between ozone exposure and T1D. CONCLUSION: Long-term exposure to ozone may increase the risk of T2D, and daily ozone exposure during pregnancy was a hazard factor for developing GDM. Decreasing ambient ozone pollution may reduce the burden of both diseases.

HNF1α upregulation and promoter hypermethylation as a cause of glucose dysregulation: a case-control study of Kashmiri MODY population.

AIM: HNF1α transcription factor regulates a network of genes involved in the development of ß-cells and also serves as a model for transcription defects in pancreatic ß-cells; mutations in this gene cause MODY. The goal of this study was to assess the promoter methylation and expression profile of the most common MODY causing gene, HNF1α, in Kashmiri MODY patients, as factors responsible for glucose dysregulation, as no such study had been performed on MODY patients in Kashmir previously. METHODS: The study included 85 Kashmiri subjects. Samples were extracted for DNA and RNA using standard protocols. The HNF1α promoter methylation profile was assessed by bisulfite conversion of the DNA followed by MSP, whereas qPCR was used for expression analysis. RESULTS: The expression of HNF1α was found to be upregulated (p value 0.0349*) in majority of MODY (60%) and T1D (72%) cases (p value 0.0349*). HNF1α expression was 1.33-fold higher in MODY cases with hypermethylated HNF1α promoters (p value 0.0360*). HNF1α expression was upregulated by 2.3-fold in MODY patients with HbA1c levels > 7% (p value 0.0025**). MODY cases with FBS levels > 7.7 mmol/l were upregulated by 0.646-fold than those with FBS levels ≤ 7.7 mmol/l (p value 0.0161*). CONCLUSION: In this study, we found that as glucose dysregulation progresses, blood FBS, RBS, and HbA1c levels rise, and that at higher levels, HNF1α expression rises as well. From the results obtained, we may conclude that HNF1α is strongly upregulated in MODY, thus indicating the deleterious effect of over expression of HNF1α gene on glucose regulation.

Nighttime hypoglycemia in Japanese children with type 1 diabetes mellitus treated with multiple daily injection insulin therapy.

Prevention of hypoglycemia is an important strategy for glycemic management in patients with type 1 diabetes mellitus (T1D). Hypoglycemia is difficult to recognize at night while sleeping, particularly when using multiple daily injection (MDI) insulin therapy rather than sensor-augmented insulin-pump therapy. Therefore, it is possible that patients with T1D are at higher risk of nocturnal hypoglycemia when insulin is administered using an MDI regimen. We investigated nocturnal hypoglycemia in 50 pediatric patients with T1D on MDI insulin therapy using data from an intermittently scanned continuous glucose monitoring (isCGM) system. Hypoglycemia was observed on 446 of the 1,270 nights studied. Most of the hypoglycemic episodes were severe (blood glucose <54 mg/dL). On nights when hypoglycemia occurred, the blood glucose concentrations measured using finger-stick blood glucose monitoring (FSGM) before sleep and the next morning were lower than nights when hypoglycemia did not occur. However, few values were below the normal blood glucose range, suggesting that FSGM alone may be insufficient to detect nocturnal hypoglycemia. Approximately 7% of time was spent below the normal glucose range during the 10 hours from 21:00 to 7:00 the next morning. This result suggests that the patients on MDI insulin therapy could end up spending more time in hypoglycemia than is recommended by the American Diabetes Association (time below range <4.0% of time per day). Monitoring glucose levels overnight using an isCGM sensor may improve glycemic management via automatic detection of blood glucose peaks and troughs.

A biomimetic five-module chimeric antigen receptor (5MCAR) designed to target and eliminate antigen-specific T cells.

T cells express clonotypic T cell receptors (TCRs) that recognize peptide antigens in the context of class I or II MHC molecules (pMHCI/II). These receptor modules associate with three signaling modules (CD3γε, δε, and ζζ) and work in concert with a coreceptor module (either CD8 or CD4) to drive T cell activation in response to pMHCI/II. Here, we describe a first-generation biomimetic five-module chimeric antigen receptor (5MCAR). We show that 1) chimeric receptor modules built with the ectodomains of pMHCII assemble with CD3 signaling modules into complexes that redirect cytotoxic T lymphocyte (CTL) specificity and function in response to the clonotypic TCRs of pMHCII-specific CD4+ T cells, and 2) surrogate coreceptor modules enhance the function of these complexes. Furthermore, we demonstrate that adoptively transferred 5MCAR-CTLs can mitigate type I diabetes by targeting autoimmune CD4+ T cells in NOD mice. This work provides a framework for the construction of biomimetic 5MCARs that can be used as tools to study the impact of particular antigen-specific T cells in immune responses, and may hold potential for ameliorating diseases mediated by pathogenic T cells.