Β-cell Autoimmunity Research Articles

RISING STARS: Evidence for established and emerging forms of β-cell death.

β-Cell death contributes to β-cell loss and insulin insufficiency in type 1 diabetes (T1D), and this β-cell demise has been attributed to apoptosis and necrosis. Apoptosis has been viewed as the lone form of programmed β-cell death, and evidence indicates that β-cells also undergo necrosis, regarded as an unregulated or accidental form of cell demise. More recently, studies in non-islet cell types have identified and characterized novel forms of cell death that are biochemically and morphologically distinct from apoptosis and necrosis. Several of these mechanisms of cell death have been categorized as forms of regulated necrosis and linked to inflammation and disease pathogenesis. In this review, we revisit discoveries of β-cell death in humans with diabetes and describe studies characterizing β-cell apoptosis and necrosis. We explore literature on mechanisms of regulated necrosis including necroptosis, ferroptosis and pyroptosis, review emerging literature on the significance of these mechanisms in β-cells, and discuss experimental approaches to differentiate between various mechanisms of β-cell death. Our review of the literature leads us to conclude that more detailed experimental characterization of the mechanisms of β-cell death is warranted, along with studies to better understand the impact of various forms of β-cell demise on islet inflammation and β-cell autoimmunity in pathophysiologically relevant models. Such studies will provide insight into the mechanisms of β-cell loss in T1D and may shed light on new therapeutic approaches to protect β-cells in this disease.

An Insulin-Chromogranin A Hybrid Peptide Activates DR11-Restricted T Cells in Human Type 1 Diabetes.

Hybrid insulin peptides (HIPs) formed through covalent cross-linking of proinsulin fragments to secretory granule peptides are detectable within murine and human islets. The 2.5HIP (C-peptide-Chromogranin A (CgA) HIP), recognized by the diabetogenic BDC-2.5 clone, is a major autoantigen in the NOD mouse. However, the relevance of this epitope in human disease is currently unclear. A recent study probed T-cell reactivity toward HIPs in patients with type 1 diabetes, documenting responses in one third of the subjects and isolating several HIP-reactive T-cell clones. In this study, we isolated a novel T cell clone and showed that it responds vigorously to the human equivalent of the 2.5HIP. Although the responding subject carried the risk-associated DRB1*04:01/DQ8 haplotype, the response was restricted by DRB1*11:03 (DR11). HLA class II tetramer staining revealed higher frequencies of HIP9-reactive T cells in individuals with diabetes than in controls. Furthermore, in DR11+ subjects carrying the DRB4 allele, HIP9-reactive T-cell frequencies were higher than observed frequencies for the immunodominant proinsulin 9-28 epitope. Finally, there was a negative correlation between HIP9-reactive T-cell frequency and age at diagnosis. These results provide direct evidence that this C-peptide-CgA HIP is relevant in human type 1 diabetes and suggest a mechanism by which non-risk HLA haplotypes may contribute to the development of β-cell autoimmunity.

Potential Protective Effect of Anti-zinc Transporter 8 Autoantibodies on Gestational Diabetes Mellitus in Iraqi Population

Background: The human zinc transporter 8 (ZNT8), also known as the solute carrier family 30A, member 8 (SLC30A8), is a β-cell specific integral membrane protein, mainly restricted to the membrane of insulin secretory granules. ZnT8 plays a crucial role in both insulin synthesis and secretion as well as the viability of β-cells. The recently identified autoantibodies targeting the β-cell surface epitopes of ZnT8 have been proposed as a new risk factor for gestational diabetes mellitus (GDM). Due to the lack of prior research studies on the role of β-cell surface autoantibodies against ZnT8 in the immunologic etiology of GDM in Iraqi population, this study has been designed to explore the association between the rs13266634 C>T polymorphism in the SLC30A8 gene and the serum levels of ZnT8 as well as Zinc Transporter-8 Autoantibody (ZnT8A) in women diagnosed with GDM. Methods: A total of 50 participants with GDM and 50 controls from the Baghdad Teaching Hospital/Pregnancy Care unit at the Medical City, Baghdad, Iraq, were recruited in this case–control study. Serum levels of ZnT8 and ZnT8A were assayed with enzyme-linked immunosorbent assay, and Taqman real time polymerase chain reaction (RT-PCR) was used for rs13266634 single nucleotide polymorphism (SNP) genotyping. Results: ZnT8A levels were significantly lower in women with GDM than non-GDM women (P ≤ 0.01). A ZnT8A level lower than 20.0 pg/mL was significantly associated with a threefold higher risk for GDM with P ≤ 0.001. ZnT8 levels were significantly higher in the GDM subjects (P ≤ 0.05). The T allele at the rs13266634 C>T SNP significantly conferred a higher risk of GDM (P = 0.002). In view of that, the TT genotype, compared to the CC genotype, showed a significant association with increased GDM risk (P ≤ 0.01). Serum ZnT8A concentrations were significantly low among GDM women who had CT genotype (P = 0.003). Conclusion: The T variant at the SLC30A8 rs13266634 C>T polymorphism appears to play a key role in determining the β-cell autoimmunity by inducing an autoantibody response due to its hyperactivity of zinc transportation.

Teplizumab: an FDA- approved drug, marks milestone in treatment of type 1 diabetes

Diabetes type-1 is a chronic disease characterized by immune-mediated destruction of insulin-producing beta cells in the pancreas. It progresses through distinct stages at varying rates, with stage 1 being β-cell autoimmunity with normal blood sugar, stage 2 being β-cell autoimmunity with dysglycemia, and stage 3 being symptomatic disease onset.

OR12-01 Blocking The Maladaptive Integrated Stress Response Increases Immunosuppressive PD-L1 In Pancreatic β-Cells

Abstract Disclosure: C. Muralidharan: None. F.H. huang: None. S.C. May: None. J. Enriquez: None. J.B. Nelson: None. E. Wang: None. A. Chakraborthy: None. K.T. Figatner: None. S.N. Navitskaya: None. S.A. Tersey: None. R.G. Mirmira: None. In type 1 diabetes (T1D), the immune system destroys the insulin-secreting β-cells. This autoimmune attack may be triggered by the β-cells themselves when they encounter viral infections or changes in gut microbiome or diet, years before clinical diagnosis of T1D. In response to these stressors, four kinases (PERK, PKR, GCN2, and HRI) activate the integrated stress response (ISR), which temporarily halts protein translation to promote cellular survival. However, if prolonged, the ISR can render β-cells dysfunctional. Therefore, we hypothesized that inhibiting the ISR under chronic inflammatory stress would suppress β-cell autoimmunity and reduce T1D risk. To test this, we pre-treated human islets with ISR inhibitors (ISRIB or a novel inhibitor of PERK, HC-PERKi) and then exposed them to proinflammatory cytokines (50 IU/mL IL-1β + 1000 IU/mL IFNγ) for 24h. As expected, cytokine treatment blocked protein translation, as revealed by polyribosomal profiling. Consistent with this, we saw reduced total protein synthesis (50% decrease) by puromycin incorporation assay. These effects were partially reversed by pretreating with ISR inhibitors. To determine if ISR inhibition delays or prevents diabetes development, we treated female pre-diabetic non-obese diabetic (NOD) mice with vehicle or HC-PERKi for four weeks (6-10 weeks of age). Compared to controls, NOD mice that received HC-PERKi showed a significant delay in diabetes development. Single cell RNA-sequencing analysis of the pancreatic islets revealed alterations in pathways involved in antigen processing and presentation in the β-cell clusters of HC-PERKi islets. Consistent with this observation, spatial proteomics analysis of the pancreatic β-cell area of HC-PERKi islets revealed a striking upregulation of programmed death-ligand 1 (PD-L1), an immune checkpoint regulator that suppresses adaptive T-cell immunity. Notably, there was no change in transcript levels of PD-L1, suggesting that PD-L1 levels are post-translationally regulated. Collectively, our studies show that inhibition of the ISR activates general protein synthesis, reduces immunogenicity via increased β-cell PD-L1 levels, and decreases T1D risk. Whereas the ISR is an adaptive response, our work emphasizes how the ISR could become maladaptive under chronic inflammation and promote β-cell autoimmunity. Presentation: Friday, June 16, 2023

SAT044 Cornus officinalis Decreases Incidence Of Type 1 Diabetes Onset And Hyperglycemia In The Non-obese Diabetic Mouse

Abstract Disclosure: J.D. Fletcher: None. G.E. Olsson: None. B.R. Burkhardt: None. Currently, there is only one FDA recently approved interventional agent (teplizumab) that can delay the onset of Type 1 Diabetes (T1D) by slowing the clinical progression of pancreatic β-cell autoimmunity and inhibiting the eventual loss of insulin production. Cornus officinalis (CO) is a highly popular ethnopharmacological treatment for diabetes and has been actively studied by our research group. Our earlier findings revealed in vitro that CO application to the pancreatic 1.1B4 β-cell line can promote pancreatic β-cell viability, metabolic activity, prevention of cytokine mediated cell death and expression of important cytoprotective pathways through promotion of autophagy and the KEAP1-Nrf2 mediated antioxidant response (PMID: 36100124 and 31255730). To further determine the clinical efficacy and biological effect of CO in-vivo, we investigated if oral delivery of CO was capable of inhibiting or delaying the onset of T1D in the non-obese diabetic (NOD) mouse (n = 7 to 10). Ten-week-old NOD male mice were given CO or water by oral gavage for 14 weeks once daily 5 days per week. Our experimental groups consisted of CO treated (CT), water treated (WT), and a no treatment or handling control group (NTH). CO was prepared by water extraction from a commercial source (Evergreen) at a concentration of 250 mg/ml and delivered by oral gavage in 200 µl. Glucose levels were measured every 3 days via glucometer (Contour Next) from tail vein collections. Diabetic onset was determined by two independent readings above 250 mg/dl. T1D incidence per group was as follows: CO (30%), WT (60%) and NTH (86%). Diabetic onset was significantly different between groups (Log rank test, p < 0.05). In addition, appearance of hyperglycemia (single glucose reading >130 mg/dl) was delayed in the CO treated NOD mice as compared to WT and NTH groups (p < 0.001). Further analysis is ongoing examining the concentration of c-peptide and determination of pancreatic insulitis by H&E staining. No harmful effects were observed in the CT group and body weights did not differ across experimental groups. In conclusion, our findings suggest that CO may have therapeutic potential as both a safe and effective interventional agent to delay the onset of T1D. Presentation: Saturday, June 17, 2023

THU274 Gluten Free Diet Reduces Systemic Innate Inflammation in Children Genetically Susceptible To Type 1 Diabetes

Abstract Disclosure: A.T. Coren: None. M.F. Roethle: None. L. Zhang: None. A.Y. Pan: None. S. Jia: None. M.J. Hessner: None. S.M. Cabrera: None. While genetic predisposition for type 1 diabetes (T1D) is strongly conferred by HLA-DR3 and/or HLA-DR4, shifting environmental factors that potentiate β-cell autoimmunity are believed responsible for increasing T1D incidence. Evidence suggests that intestinally mediated exposures, such as the Western diet, influence immunity and T1D risk. Gluten is a potential mediator of inflammation. We have described endogenous innate inflammation in individuals with T1D and their healthy siblings and that T1D progresses when this innate state is augmented by additional inflammatory signals prior to development of protective counter-regulatory mechanisms. We hypothesize that, in genetically susceptible hosts, gluten promotes the innate inflammation that potentiates T1D progression and that its removal will abrogate this risk. In an exploratory pilot study, we enrolled healthy children who had a full sibling with T1D to a 4-wk gluten free diet (GFD). Adherence was measured by self-report and fecal gluten peptide. Pre- and post-GFD plasma was analyzed for changes to microbial antigen detection by TLR4 activation, short chain fatty acids (SCFAs), cytokines, and chemokines. Wilcoxon signed rank tests were used to examine paired data. Stool microbial composition was measured by 16s rRNA bacterial gene sequencing and analyzed by generalized linear mixed models with negative binominal distribution. P<0.05 was considered significant. 28 participants completed the study (mean 13 years, range 2.7-22.1, 20 (71%) females, 22 (79%) non-Hispanic white, 9 (32%) pre-pubertal). 21% had a first degree relative with celiac disease and 11 (39%) had HLA-DR3 and/or DR4. At baseline, 50% had inadequate dietary fiber intake. There was no attrition, but 29% admitted to occasional gluten consumption or had detectable fecal gluten peptides. TLR4 activity trended lower post-GFD (p =0.06). Post-GFD, plasma acetate, an anti-inflammatory SCFA, was increased; hexanoate, an inflammatory fatty acid, was decreased (p<0.001). The plasma-to-fecal ratio of acetate, propionate, butyrate, valerate, and hexanoate were increased. Several inflammatory cytokines/chemokines were significantly reduced post-GFD (IFNα, IL-7, MCP-1, CCL5, Eotaxin-2) but IL-1α and TNFβ increased. Fecal 16s rRNA analyses revealed no GFD-driven differences in alpha or beta diversity, but at genus level, post-GFD samples had lower abundances of Roseburia, Faecalibacterium, and Bifidobacterium and higher abundances of Bacteroides. In sum, removal of gluten reduced several markers of systemic inflammation, independent of HLA-DR3/DR4, suggesting gluten may potentiate innate inflammation and T1D progression in those with underlying susceptibility. This may occur by altering gut barrier integrity and/or shifts in microbial taxa/metabolites. These data suggest mechanisms by which gluten may directly and indirectly drive T1D progression. Presentation: Thursday, June 15, 2023

28-OR: Characterising a Novel Peptide That Inhibits and Reverses Type 1 Diabetes

Aims: Interventions that regenerate functional pancreatic β-cells are a potential treatment option for type 1 diabetes. D6PV is a small peptide that lowers plasma triglyceride levels. We have found that it also enhances expression of the β-cell survival gene Pdx1 and stimulates insulin production in INS-1E insulinoma cells. This study asks whether D6PV delays diabetes onset and preserves β-cell mass in mice with autoimmune β-cell loss. Methods: Female 8-week-old NOD/ShiLtJ (NOD) mice (n=10-20/group) were treated twice/week for 16 weeks with D6PV (40 mg/kg i.p) or PBS. Diabetes onset was evaluated by measuring blood glucose levels. A separate cohort of female NOD mice were treated with D6PV or PBS twice/week for 4 weeks after they developed diabetes. Glycaemic control was evaluated by glucose tolerance test (1 g/kg i.p). Islet insulin content was quantified by immunostaining of paraffin-embedded, formalin-fixed pancreatic tissue. Expansion of CD8+ T-cells was analysed ex vivo from OTI-TCR transgenic mouse splenocytes and healthy human donors following stimulation via IL-7/15 and incubation ± D6PV. Results: D6PV treatment for 16 weeks decreased fed and fasted blood glucose levels (p<0.05 for both) and delayed diabetes onset in NOD mice (p<0.01). This was accompanied by increased insulin +ve islet area in the D6PV treated, but not the PBS treated animals (p<0.05). D6PV treatment also reduced lymphocyte infiltration into islets but increased lymphocytic migration to the basement membrane (0.2 ± 0.1% vs 1.8 ± 1.7%, p<0.05). When NOD mice with diabetes were treated with D6PV, glucose tolerance improved (AUC 1167±341 vs 543±328, p<0.01). Treatment of both mouse and human cytokine-activated isolated CD8+ T-cells with D6PV suppressed T-cell expansion (p<0.001). Conclusions: D6PV treatment delays diabetes onset, improves glycaemic control in mice with established disease, increases pancreatic insulin expression and inhibits T-cell expansion in NOD mice. D6PV is a potential treatment option for type 1 diabetes. Disclosure T.W.King: None. S.S.Tay: None. F.Colakoglu: None. M.Devalaraja: None. A.Remaley: None. M.Biro: None. B.Cochran: None. K.Rye: None. Funding National Health and Medical Research Council of Australia (RG201951)

S-17-2: CLUSTER ANALYSIS OF DIABETES AND HYPERTENSION

Diabetes mellitus is classified into type 1 diabetes mellitus (T1DM) and type 2 diabetes mellitus (T2DM) according to etiology. T1DM occurs due to autoimmune β-cell destruction, usually leading to absolute insulin deficiency, whereas T2DM occurs due to a heterogenous combination of a relative insulin deficiency and insulin resistance. A data-driven cluster analysis reported five exclusive subgroups for diabetes: cluster 1 (severe autoimmune diabetes [SAID]), cluster 2 (severe insulin-deficient diabetes [SIDD]), cluster 3 (severe insulin-resistant diabetes [SIRD]), cluster 4 (mild obesity-related diabetes [MOD]), and cluster 5 (mild age-related diabetes [MARD]) (Ahlqvist et al, 2018). The subgroups have an advantage over the other classification because it uses simple but pathophysiologically feasible factors and is proven to apply to ethnic and racial differences to estimate diabetic complications (Diabetes Res Clin Pract 2021:180;109067). The SIRD cluster shows obesity and moderate to severe insulin resistance with hyperinsulinemia. Under severe metabolic deterioration based on insulin resistance through ectopic fat accumulation, individuals with SIRD are at high risk of developing atherosclerotic cardiovascular disease (ASCVD). SIRD confers the highest risk of developing diabetic kidney disease (DKD), commonly in Caucasians [Ahlqvist et al., 2018)] and non-Caucasians [Tanabe, 2020]. I will discuss the possible connection between cluster-derived diabetes subgroups and hypertension-associated complications.

Acute presentation of immunotherapy-related diabetes mellitus without ketoacidosis, low C-peptide or elevated HbA1c.

The rapid rise in the use of immune checkpoint inhibitors as systemic cancer therapy has seen the emergence of immunotherapy-induced diabetes, a severe irreversible immunotherapy-related adverse event. Affected patients typically present with diabetic ketoacidosis (DKA) and low C-peptide consistent with insulin deficiency secondary to autoimmune β-cell destruction. We present the unusual case of a 61-year-old female with metastatic ampullary duodenal adenocarcinoma with primary tumour adjacent to the pancreatic head. She was commenced on immunotherapy after conventional systemic chemotherapy. Acute-onset hyperglycaemia was detected after 7 weeks on weekly blood glucose monitoring, with no glucocorticoid use or prior history of diabetes. On presentation, there was no evidence of DKA, and her glycated haemoglobin level was within the normal non-diabetic range at 5.3%, reflecting the acuity of her presentation. Initial serum C-peptide was preserved; however, it became undetectable a few weeks later, confirming insulin deficiency. We describe a case of atypical presentation of immunotherapy-induced diabetes, review the existing literature on this emerging clinical entity and discuss the differential diagnosis for new-onset diabetes mellitus in patients with metastatic cancer. Regular proactive glycaemic monitoring in patients receiving immunotherapy, particularly antibodies against programmed death ligand 1 and PD1, can facilitate very early detection of immunotherapy-induced diabetes, prompting insulin commencement and avoiding life-threatening presentations of diabetic ketoacidosis. Glycated haemoglobin can be within the normal range in patients diagnosed acutely with immunotherapy-induced diabetes. Serum C-peptide can be preserved initially in patients diagnosed with immunotherapy-induced diabetes but is likely to become undetectable during their illness. New-onset diabetes in patients with metastatic cancer carries a broad differential diagnosis.

Evaluating the Immunopathogenesis of Diabetes After Acute Pancreatitis in the Diabetes RElated to Acute Pancreatitis and Its Mechanisms Study: From the Type 1 Diabetes in Acute Pancreatitis Consortium.

The association between acute pancreatitis (AP) and diabetes mellitus (DM) has long been established, with the initial descriptions of AP patients presenting with DM after a bout of AP published in the 1940s and 50s. However, the potential mechanisms involved, particularly those components related to the immune system, have not been well defined. The Diabetes RElated to Acute pancreatitis and its Mechanisms (DREAM) study is a multicenter clinical study designed to understand the frequency and phenotype of DM developing after AP. This article describes one objective of the DREAM study: to determine the immunologic mechanisms of DM after AP, including the contribution of β-cell autoimmunity. This component of the study will assess the presence of islet autoimmunity, as well as the magnitude and kinetics of the innate and adaptive immune response at enrollment and during longitudinal follow-up after 1 or more episodes of AP. Finally, DREAM will evaluate the relationship between immune features, DM development, and pancreatitis etiology and severity.

9-OR: ADA Presidents' Select Abstract: m6A mRNA Methylation Regulates the Innate Immune Response in Human Beta Cells

Innate immunity is directly associated with Type 1 diabetes (T1D) . Recently, N6-methyladenosine (m6A) has been shown to modulate human β-cell biology and innate immunity. Here, we focused on the contribution of m6A in modulating T1D development. RNA-seq. in β-cells revealed downregulation of the m6A writers (Mettl3, Mettl14, and Wtap) in pre-diabetic NOD mice. Consistently, pancreases from female NOD mice and human T1D showed downregulation of METTL3 protein levels in insulin-positive cells as the disease progressed. m6A-sequencing in human T1D versus control islets and intersection with differentially expressed genes (DEGs) in T1D β-cells from a single-cell RNA seq. dataset, revealed enriched pathways associated with ER function, T1D, and apoptosis. Pro-inflammatory cytokines are directly linked to β-cell autoimmunity and are considered a useful tool to study T1D onset. We applied m6A-sequencing in cytokine-treated human islet preparations, and in parallel studies, treated EndoC-βH1 cells with cytokines followed by RNA-sequencing. Intersection of m6A-decorated and common DEGs in human islets and EndoC-βH1 cells revealed enrichment in pathways associated with the innate immune response. METTL3 silencing in EndoC-βH1 impacted several innate immune mediators upon cytokine challenge. Incubation of human islets from multiple donors with ER-stress inducers, ROS donors, NO donors, and ROS or NO scavengers revealed that pre-existing ER stress and ROS decrease METTL3, while physiological levels of NO upregulate METTL3. We conclude that ROS drives METTL3 downregulation associated with T1D. Exploring therapeutic relevance by AAV-8 mediated gene delivery showed that β-cell specific upregulation of Mettl3 leads to a decrease in hyperglycemia during early stages of T1D in female NOD mice. Together, these results demonstrate a novel layer of regulation in human β-cells in the context of T1D and point to targeting METTL3 as a therapeutic approach to promote β-cell survival and improve glycemia. Disclosure D.F.De jesus: n/a. D.L.Eizirik: None. R.Kulkarni: Advisory Panel; Biomea, Novo Nordisk, REDD Pharma, Consultant; Relay Therapeutics, Research Support; Inversago, SerPlus. Z.Zhang: Research Support; SinoVac. N.K.Brown: None. G.Basile: None. L.Xiao: None. S.Kahraman: Employee; Boehringer Ingelheim International GmbH. C.E.Mathews: None. A.C.Powers: None. M.A.Atkinson: None. Funding American Diabetes Association (7-21-PDF-140) ; R01 DK067536R01 DK103215R01 DK117639

Stress Hyperglycemia, Diabetes Mellitus and COVID-19 Infection: Risk Factors, Clinical Outcomes and Post-Discharge Implications.

The novel severe acute respiratory distress syndrome-coronavirus 2 (SARS-CoV-2) has caused one of the most substantial pandemics that has affected humanity in the last century. At the time of the preparation of this review, it has caused the death of around 5 million people around the globe. There is ample evidence linking higher mortality risk rates from Coronavirus disease-19 (COVID-19) with male gender, advancing age and comorbidities, such as obesity, arterial hypertension, cardiovascular disease, chronic obstructive pulmonary disease, diabetes mellitus, and cancer. Hyperglycemia has been found to be accompanying COVID-19 not only in individuals with overt diabetes. Many authors claim that blood glucose levels should also be monitored in non-diabetic patients; moreover, it has been confirmed that hyperglycemia worsens the prognosis even without pre-existing diabetes. The pathophysiological mechanisms behind this phenomenon are complex, remain controversial, and are poorly understood. Hyperglycemia in the setting of COVID-19 could be a consequence of deterioration in pre-existing diabetes, new-onset diabetes, stress-induced or iatrogenic due to substantial usage of corticosteroids within the context of a severe COVID-19 infection. It is also plausible that it might be a result of adipose tissue dysfunction and insulin resistance. Last but not least, SARS-CoV-2 is also claimed to trigger sporadically direct β-cell destruction and β-cell autoimmunity. Pending further validations with longitudinal data are needed to legitimize COVID-19 as a potential risk factor for the development of diabetes. Hereby, we present an emphasized critical review of the available clinical data in an attempt to unravel the complex mechanisms behind hyperglycemia in COVID-19 infection. The secondary endpoint was to evaluate the bidirectional relationship between COVID-19 and diabetes mellitus. As the worldwide pandemic is still expanding, demand for answering these questions is arising. It will be of immense help for the management of COVID-19 patients, as well as for the implementation of post-discharge policies for patients with a high risk of developing diabetes.

Incidence of an Insulin-Requiring Hyperglycemic Syndrome in SARS-CoV-2-Infected Young Individuals: Is It Type 1 Diabetes?

Pancreatic ACE2 receptor expression, together with increased prevalence of insulin-requiring hyperglycemia in patients with coronavirus disease 2019 (COVID-19), suggested that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pancreatic infection might trigger a β-cell-selective inflammation precipitating autoimmune type 1 diabetes (T1D). We examined T1D incidence in patients with COVID-19 inside a large, global population using a "big data" approach. The incidence in 0-30-year-old patients with confirmed COVID-19 over an ∼15-month period from the beginning of the COVID-19 pandemic was compared with an age-matched population without COVID-19 inside the TriNetX COVID-19 Research Network (>80 million deidentified patient electronic medical records globally). The cohorts were used to generate outcomes of T1D postindex. In those up to 18 years of age, the incidence of insulin-requiring diabetes that could represent T1D in patients with already diagnosed, confirmed COVID-19 was statistically indistinguishable from the control population without COVID-19. In contrast, in those aged 19-30 years, the incidence was statistically greater. These data suggest that the incidence of T1D among patients with COVID-19 <30 years of age, at least up to this time since the beginning of the pandemic, is not greater when compared with an age-, sex-, and BMI-matched population without COVID-19. Nevertheless, we caution that patients with COVID-19 could be asymptomatic of a diabetic/prediabetic state and therefore would not be expected to come to medical attention, remaining undiagnosed. Hence, it is still possible that asymptomatic virus-infected individuals could acquire β-cell autoimmunity, eventually progressing to dysglycemia and clinical T1D at higher rates.

Safety of the use of gold nanoparticles conjugated with proinsulin peptide and administered by hollow microneedles as an immunotherapy in type 1 diabetes.

Antigen-specific immunotherapy is an immunomodulatory strategy for autoimmune diseases, such as type 1 diabetes, in which patients are treated with autoantigens to promote immune tolerance, stop autoimmune β-cell destruction and prevent permanent dependence on exogenous insulin. In this study, human proinsulin peptide C19-A3 (known for its positive safety profile) was conjugated to ultrasmall gold nanoparticles (GNPs), an attractive drug delivery platform due to the potential anti-inflammatory properties of gold. We hypothesised that microneedle intradermal delivery of C19-A3 GNP may improve peptide pharmacokinetics and induce tolerogenic immunomodulation and proceeded to evaluate its safety and feasibility in a first-in-human trial. Allowing for the limitation of the small number of participants, intradermal administration of C19-A3 GNP appears safe and well tolerated in participants with type 1 diabetes. The associated prolonged skin retention of C19-A3 GNP after intradermal administration offers a number of possibilities to enhance its tolerogenic potential, which should be explored in future studies

CD8+ T Cells Variably Recognize Native Versus Citrullinated GRP78 Epitopes in Type 1 Diabetes.

In type 1 diabetes, autoimmune β-cell destruction may be favored by neoantigens harboring posttranslational modifications (PTMs) such as citrullination. We studied the recognition of native and citrullinated glucose-regulated protein (GRP)78 peptides by CD8+ T cells. Citrullination modulated T-cell recognition and, to a lesser extent, HLA-A2 binding. GRP78-reactive CD8+ T cells circulated at similar frequencies in healthy donors and donors with type 1 diabetes and preferentially recognized either native or citrullinated versions, without cross-reactivity. Rather, the preference for native GRP78 epitopes was associated with CD8+ T cells cross-reactive with bacterial mimotopes. In the pancreas, a dominant GRP78 peptide was instead preferentially recognized when citrullinated. To further clarify these recognition patterns, we considered the possibility of citrullination in the thymus. Citrullinating peptidylarginine deiminase (Padi) enzymes were expressed in murine and human medullary epithelial cells (mTECs), with citrullinated proteins detected in murine mTECs. However, Padi2 and Padi4 expression was diminished in mature mTECs from NOD mice versus C57BL/6 mice. We conclude that, on one hand, the CD8+ T cell preference for native GRP78 peptides may be shaped by cross-reactivity with bacterial mimotopes. On the other hand, PTMs may not invariably favor loss of tolerance because thymic citrullination, although impaired in NOD mice, may drive deletion of citrulline-reactive T cells.

Visceral Adipose Tissue: A New Target Organ in Virus-Induced Type 1 Diabetes.

Type 1 diabetes (T1D) is a proinflammatory pathology that leads to the specific destruction of insulin producing β-cells and hyperglycaemia. Much of the knowledge about type 1 diabetes (T1D) has focused on mechanisms of disease progression such as adaptive immune cells and the cytokines that control their function, whereas mechanisms linked with the initiation of the disease remain unknown. It has been hypothesized that in addition to genetics, environmental factors play a pivotal role in triggering β-cell autoimmunity. The BioBreeding Diabetes Resistant (BBDR) and LEW1.WR1 rats have been used to decipher the mechanisms that lead to virus-induced T1D. Both animals develop β-cell inflammation and hyperglycemia upon infection with the parvovirus Kilham Rat Virus (KRV). Our earlier in vitro and in vivo studies indicated that KRV-induced innate immune upregulation early in the disease course plays a causal role in triggering β-cell inflammation and destruction. Furthermore, we recently found for the first time that infection with KRV induces inflammation in visceral adipose tissue (VAT) detectable as early as day 1 post-infection prior to insulitis and hyperglycemia. The proinflammatory response in VAT is associated with macrophage recruitment, proinflammatory cytokine and chemokine upregulation, endoplasmic reticulum (ER) and oxidative stress responses, apoptosis, and downregulation of adipokines and molecules that mediate insulin signaling. Downregulation of inflammation suppresses VAT inflammation and T1D development. These observations are strikingly reminiscent of data from obesity and type 2 diabetes (T2D) in which VAT inflammation is believed to play a causal role in disease mechanisms. We propose that VAT inflammation and dysfunction may be linked with the mechanism of T1D progression.

Novel autoantibodies to the β-cell surface epitopes of ZnT8 in patients progressing to type-1 diabetes

Type 1 diabetes (T1D) is a chronic autoimmune disease characterized by autoimmune destruction of insulin-producing β-cells in pancreatic islets. Seroconversions to islet autoantibodies (IAbs) precede the disease onset by many years, but the role of humoral autoimmunity in the disease initiation and progression are unclear. In the present study, we identified a new IAb directed to the extracellular epitopes of ZnT8 (ZnT8ec) in newly diagnosed patients with T1D, and demonstrated immunofluorescence staining of the surface of human β-cells by autoantibodies to ZnT8ec (ZnT8ecA). With the assay specificity set on 99th percentile of 336 healthy controls, the ZnT8ecA positivity rate was 23.6% (74/313) in patients with T1D. Moreover, 30 children in a longitudinal follow up of clinical T1D development were selected for sequential expression of four major IAbs (IAA, GADA, IA-2A and ZnT8icA). Among them, 10 children were ZnT8ecA positive. Remarkably, ZnT8ecA was the earliest IAb to appear in all 10 children. The identification of ZnT8ec as a cell surface target of humoral autoimmunity in the earliest phase of IAb responses opens a new avenue of investigation into the role of IAbs in the development of β-cell autoimmunity.

Long-Term Follow-up of β-Transfusion-Dependent Thalassemia (TDT) Normoglycemic Patients with Reduced Insulin Secretion to Oral Glucose Tolerance Test (OGTT): A Pilot Study.

ObjectiveTo study the endocrine pancreas’ function in transfusion-dependent β-thalassemia (β-TDT) patients with a normal glucose tolerance test (NGT) and hypoinsulinemia. In addition, the prospective long–term follow-up using an annual oral glucose tolerance test (OGTT) to detect any abnormality of glucose metabolism.Patients and methodsSeven β-TDT patients (mean age 22.4 ± 4.2 years) with NGT and inadequate insulin response (hypoinsulinemia) to OGTT were referred for a second opinion to an Italian Centre.ResultsThe first-phase insulin response (FPIR), expressed as the sum of 1 and 3 minutes insulin, to intravenous glucose tolerance test (IVGTT), was between the 1st and 3rd percentile in two patients and between the 3rd and 10th percentile in five. The results were not associated with β-cell autoimmunity. After 43 ± 26 months (range 11 – 80 months) of follow-up, two patients developed impaired glucose tolerance (IGT), three both IGT and impaired fasting glucose (IFG) and two overt diabetes mellitus (DM). Interestingly, the patients who developed DM had, at baseline, the lowest value of the insulinogenic index (IGI: 0.08 and 0.25), defined as the ratio of the increment of plasma insulin to plasma glucose during the first 30 minutes after OGTT. Moreover, a significant correlation was found between the IGI at baseline and at follow-up in the patients who developed IGT with or without IFG (R= 0.927; P: 0.023). A significant reduction of Matsuda insulin sensitivity index (ISIM) and Insulin Secretion-Sensitivity Index-2 (ISSI-2) was documented in the study cohort at the diagnosis of IFG, IGT, and DM. There was a significant inverse correlation between ISSI-2 and area under the curve plasma glucose (AUC-PG).ConclusionsThese data demonstrated, for the first time, progressive deterioration in glucose homeostasis in β-TDT subjects with NGT and hypoinsulinemia and that the ISSI-2 index may be a valuable parameter to identify patients at high risk for developing glucose dysregulation.

Precision medicine in diabetes-Finally some light at the end of the tunnel?

Precision medicine in diabetes-Finally some light at the end of the tunnel?