The pathogenesis and natural history of type 1 diabetes

New Approaches to the Immunotherapy of Type 1 Diabetes Mellitus Using Interleukin-27

Type 1 diabetes (T1D) is a pancreatic beta cell specific autoimmune disease. One of the most significant current discussions in T1D studies is therapy. Since the conventional therapy, islet transplantation and external insulin, e.g., cannot prevent the destructive autoimmune process against original beta cells and persistent hyperglycemia remains, so recent developments in the field of T1D therapy paved the way to a renewed interest in immunotherapy based on the disease process, especially monoclonal antibody therapy. Due to encouraging laboratory results, cytokine antibody-based drugs could be effective in the clinical direction of the T1D disease process. Hence, implementation of this approach can be useful to improve clinical and laboratory manifestations of T1D.

Therapeutic potential of umbilical cord blood cells for type 1 diabetes mellitus

Type 1 diabetes mellitus (T1DM) is a chronic disorder that results from autoimmune-mediated destruction of pancreatic islet β-cells. However, to date, no conventional intervention has successfully treated the disease. The optimal therapeutic method for T1DM should effectively control the autoimmunity, restore immune homeostasis, preserve residual β-cells, reverse β-cell destruction, and protect the regenerated insulin-producing cells against re-attack. Umbilical cord blood is rich in regulatory T (T(reg)) cells and multiple types of stem cells that exhibit immunomodulating potential and hold promise in their ability to restore peripheral tolerance towards pancreatic islet β-cells through remodeling of immune responses and suppression of autoreactive T cells. Recently, reinfusion of autologous umbilical cord blood or immune cells from cord blood has been proposed as a novel therapy for T1DM, with the advantages of no risk to the donors, minimal ethical concerns, a low incidence of graft-versus-host disease and easy accessibility. In this review, we revisit the role of autologous umbilical cord blood or immune cells from cord blood-based applications for the treatment of T1DM.

IL-Y, a synthetic member of the IL-12 cytokine family, suppresses the development of type 1 diabetes in NOD mice

The IL-12 family of heterodimeric cytokines, consisting of IL-12, IL-23, IL-27, and IL-35, has important roles in regulating the immune response. IL-12 family members are comprised of a heterodimer consisting of α and β chains: IL-12 (p40 and p35), IL-23 (p40 and p19), IL-27 (Ebi3 and p28), and IL-35 (Ebi3 and p35). Given the combinatorial nature of the IL-12 family, we generated adenoviral vectors expressing two putative IL-12 family members not yet found naturally, termed IL-X (Ebi3 and p19) and IL-Y (p40 and p28), as single-chain molecules. Single chain IL-Y (scIL-Y), but not scIL-X, was able to stimulate significantly a unique cytokine/chemokine expression profile as well as activate STAT3 in mice, in part, through a pathway involving IL-27Rα in splenocytes. Adenoviral-mediated, intratumoral delivery of scIL-Y increased tumor growth in contrast to the anti-tumor effects of scIL-12 and scIL-23. Similarly, treatment of prediabetic NOD mice by intravenous injection of Ad.scIL-Y prevented the onset of hyperglycemia. Analysis of cells from Ad.scIL-Y-treated NOD mice demonstrated that scIL-Y reduced expression of inflammatory mediators such as IFN-γ. Our data demonstrate that a novel, synthetic member of the IL-12 family, termed IL-Y, confers unique immunosuppressive effects in two different disease models and thus could have therapeutic applications.

Expression profiling pre-diabetic mice to uncover drugs with clinical application to type 1 diabetes

In the NOD mouse model of type 1 diabetes (T1D), genetically identical mice in the same environment develop diabetes at different rates. Similar heterogeneity in the rate of progression to T1D exists in humans, but the underlying mechanisms are unclear. Here, we aimed to discover peripheral blood (PB) genes in NOD mice predicting insulitis severity and rate of progression to diabetes. We then wished to use these genes to mine existing databases to identify drugs effective in diabetes. In a longitudinal study, we analyzed gene expression in PB samples from NOD.CD45.2 mice at 10 weeks of age, then scored pancreatic insulitis at 14 weeks or determined age of diabetes onset. In a multilinear regression model, Tnf and Tgfb mRNA expression in PB predicted insulitis score (R²=0.56, P=0.01). Expression of these genes did not predict age of diabetes onset. However, by expression-profiling PB genes in 10-week-old NOD.CD45.2 mice, we found a signature of upregulated genes that predicted delayed or no diabetes. Major associated pathways included chromatin organization, cellular protein location and regulation of nitrogen compounds and RNA. In a clinical cohort, three of these genes were differentially expressed between first-degree relatives, T1D patients and controls. Bioinformatic analysis of differentially expressed genes in NOD.CD45.2 PB identified drugs that are predicted to delay or prevent diabetes. Of these drugs, 11 overlapped with drugs predicted to induce a human ‘non-progressor' expression profile. These data demonstrate that disease heterogeneity in diabetes-prone mice can be exploited to mine novel clinical T1D biomarkers and drug targets.

Proteomic Analysis of Disease Stratified Human Pancreas Tissue Indicates Unique Signature of Type 1 Diabetes

Type 1 diabetes (T1D) and type 2 diabetes (T2D) are associated with functional beta cell loss due to ongoing inflammation. Despite shared similarities, T1D is an autoimmune disease with evidence of autoantibody production, as well as a role for exocrine pancreas involvement. Our hypothesis is that differential protein expression occurs in disease stratified pancreas tissues and regulated proteins from endocrine and exocrine tissues are potential markers of disease and potential therapeutic targets. The study objective was to identify novel proteins that distinguish the pancreas from donors with T1D from the pancreas from patients with T2D, or autoantibody positive non-diabetic donors. Detailed quantitative comprehensive proteomic analysis was applied to snap frozen human pancreatic tissue lysates from organ donors without diabetes, with T1D-associated autoantibodies in the absence of diabetes, with T1D, or with T2D. These disease-stratified human pancreas tissues contain exocrine and endocrine tissues (with dysfunctional islets) in the same microenvironment. The expression profiles of several of the proteins were further verified by western blot. We identified protein panels that are significantly and uniquely upregulated in the three disease-stratified pancreas tissues compared to non-disease control tissues. These proteins are involved in inflammation, metabolic regulation, and autoimmunity, all of which are pathways linked to, and likely involved in, T1 and T2 diabetes pathogenesis. Several new proteins were differentially upregulated in prediabetic, T1D, and T2D pancreas. The results identify proteins that could serve as novel prognostic, diagnostic, and therapeutic tools to preserve functional islet mass in Type 1 Diabetes.

Sensory nerve regeneration after epithelium wounding in normal and diabetic cornea

The cornea is the most densely innervated mammalian tissue. The sensory nerves are responsible for sensations of dryness, temperature, touch, and pain, and play important roles in the blink reflex, wound healing, and tear production. Many ocular and systemic diseases can adversely affect corneal sensory nerve and consequently impair their function. One of such systemic diseases is diabetes mellitus (DM) which causes sensory degeneration, neurotrophic keratopathy (DNK), and delayed wound healing. In this review, we summarize recent discoveries revealing mechanisms underlying the pathogenesis of DNK and the impairment of sensory nerve regeneration in post wound diabetic corneas in using animal model of human diabetes. Because it is generally believed that common mechanisms are operative in the pathogenesis of diabetic peripheral neuropathy in different tissues, the findings in the corneas have implications in in other tissues such as the skin, which often leads to foot ulceration and amputation in diabetic patients.

Enhancing the discovery and development of immunotherapies for cancer using quantitative and systems pharmacology: Interleukin-12 as a case study

Recent clinical successes of immune checkpoint modulators have unleashed a wave of enthusiasm associated with cancer immunotherapy. However, this enthusiasm is dampened by persistent translational hurdles associated with cancer immunotherapy that mirror the broader pharmaceutical industry. Specifically, the challenges associated with drug discovery and development stem from an incomplete understanding of the biological mechanisms in humans that are targeted by a potential drug and the financial implications of clinical failures. Sustaining progress in expanding the clinical benefit provided by cancer immunotherapy requires reliably identifying new mechanisms of action. Along these lines, quantitative and systems pharmacology (QSP) has been proposed as a means to invigorate the drug discovery and development process. In this review, I discuss two central themes of QSP as applied in the context of cancer immunotherapy. The first theme focuses on a network-centric view of biology as a contrast to a "one-gene, one-receptor, one-mechanism" paradigm prevalent in contemporary drug discovery and development. This theme has been enabled by the advances in wet-lab capabilities to assay biological systems at increasing breadth and resolution. The second theme focuses on integrating mechanistic modeling and simulation with quantitative wet-lab studies. Drawing from recent QSP examples, large-scale mechanistic models that integrate phenotypic signaling-, cellular-, and tissue-level behaviors have the potential to lower many of the translational hurdles associated with cancer immunotherapy. These include prioritizing immunotherapies, developing mechanistic biomarkers that stratify patient populations and that reflect the underlying strength and dynamics of a protective host immune response, and facilitate explicit sharing of our understanding of the underlying biology using mechanistic models as vehicles for dialogue. However, creating such models require a modular approach that assumes that the biological networks remain similar in health and disease. As oncogenesis is associated with re-wiring of these biological networks, I also describe an approach that combines mechanistic modeling with quantitative wet-lab experiments to identify ways in which malignant cells alter these networks, using Interleukin-12 as an example. Collectively, QSP represents a new holistic approach that may have profound implications for how translational science is performed.

Cardiac autoimmunity as a novel biomarker, mediator, and therapeutic target of heart disease in type 1 diabetes

Patients with type 1 diabetes (T1D) suffer excess mortality from cardiovascular disease (CVD) that has persisted despite substantial reductions in microvascular complications. Although T1D and type 2 diabetes (T2D) are etiologically distinct, it has generally been assumed that CVD in T1D is "the same disease" as that found in T2D. Here, we review the most recent epidemiological and clinical studies on heart disease in T1D, highlighting differences between CVD in T1D and T2D. In addition, we discuss experimental and clinical evidence for a post-myocardial infarction (MI) autoimmune heart syndrome in T1D, including the development of diagnostic assays which we believe can, for the first time, differentiate between heart disease in T1D and T2D. We postulate that a clinically unrecognized form of chronic myocardial inflammation ("myocarditis") triggered by MI contributes to the poor CVD outcomes in T1D. These findings provide a conceptual shift in our understanding of CVD in T1D and have important diagnostic and therapeutic implications.

Preexisting insulin autoantibodies predict efficacy of otelixizumab in preserving residual β-cell function in recent-onset type 1 diabetes

OBJECTIVE

Immune intervention trials in recent-onset type 1 diabetes would benefit from biomarkers associated with good therapeutic response. In the previously reported randomized placebo-controlled anti-CD3 study (otelixizumab; GlaxoSmithKline), we tested the hypothesis that specific diabetes autoantibodies might serve this purpose.

RESEARCH DESIGN AND METHODS

In the included patients (n = 40 otelixizumab, n = 40 placebo), β-cell function was assessed as area under the curve (AUC) C-peptide release during a hyperglycemic glucose clamp at baseline (median duration of insulin treatment: 6 days) and every 6 months until 18 months after randomization. (Auto)antibodies against insulin (I[A]A), GAD (GADA), IA-2 (IA-2A), and ZnT8 (ZnT8A) were determined on stored sera by liquid-phase radiobinding assay.

RESULTS

At baseline, only better preserved AUC C-peptide release and higher levels of IAA were associated with better preservation of β-cell function and lower insulin needs under anti-CD3 treatment. In multivariate analysis, IAA (P = 0.022) or the interaction of IAA and C-peptide (P = 0.013) independently predicted outcome together with treatment. During follow-up, good responders to anti-CD3 treatment (i.e., IAA(+) participants with relatively preserved β-cell function [≥ 25% of healthy control subjects]) experienced a less pronounced insulin-induced rise in I(A)A and lower insulin needs. GADA, IA-2A, and ZnT8A levels were not influenced by anti-CD3 treatment, and their changes showed no relation to functional outcome.

CONCLUSIONS

There is important specificity of IAA among other diabetes autoantibodies to predict good therapeutic response of recent-onset type 1 diabetic patients to anti-CD3 treatment. If confirmed, future immune intervention trials in type 1 diabetes should consider both relatively preserved functional β-cell mass and presence of IAA as inclusion criteria.

Type 1 diabetes and polyglandular autoimmune syndrome: A review

Type 1 diabetes (T1D) is an autoimmune disorder caused by inflammatory destruction of the pancreatic tissue. The etiopathogenesis and characteristics of the pathologic process of pancreatic destruction are well described. In addition, the putative susceptibility genes for T1D as a monoglandular disease and the relation to polyglandular autoimmune syndrome (PAS) have also been well explored. The incidence of T1D has steadily increased in most parts of the world, especially in industrialized nations. T1D is frequently associated with autoimmune endocrine and non-endocrine diseases and patients with T1D are at a higher risk for developing several glandular autoimmune diseases. Familial clustering is observed, which suggests that there is a genetic predisposition. Various hypotheses pertaining to viral- and bacterial-induced pancreatic autoimmunity have been proposed, however a definitive delineation of the autoimmune pathomechanism is still lacking. In patients with PAS, pancreatic and endocrine autoantigens either colocalize on one antigen-presenting cell or are expressed on two/various target cells sharing a common amino acid, which facilitates binding to and activation of T cells. The most prevalent PAS phenotype is the adult type 3 variant or PAS type III, which encompasses T1D and autoimmune thyroid disease. This review discusses the findings of recent studies showing noticeable differences in the genetic background and clinical phenotype of T1D either as an isolated autoimmune endocrinopathy or within the scope of polyglandular autoimmune syndrome.

Type 1 diabetes epidemic in Finland is triggered by zinc-containing amorphous silica nanoparticles

Type 1 diabetes (T1D), an autoimmune disease, breaks out in some of the children who has genetic susceptibility to T1D. Besides genetic susceptibility some environmental factor(s) are required to trigger the disease. The incidence of T1D in Finland is highest in the world, so we must seek an environmental factor, that is typical for Finland and can declare many aspects of T1D epidemiology and biology. In the literature most popular trigger has been enterovirus infections. It is difficult however to find why enteroviruses would be in this role in Finland in contrary to neighbouring countries e.g. Sweden. Colloidal amorphous silica (ASi) is typical for Finnish environment in consequency of the geohistory of Finland, great part of Finland is an ancient lake and sea bottom. ASi concentrations in natural waters are high in April-June and in November, only traces can be found in the rest of months. Pure colloidal ASi is not a strong trigger for T1D, but ASi particle which has surface adsorbed tetrahedrally coordinated zinc (ASiZn) is probably the trigger which has kept it's secret up to date. Zn functions as address label which conducts the ASiZn particle to the beta cell, whose content of zinc is highest in the body. ASi particle adheres to membrane proteins distorting their tertiary structure revealing new epitopes. If the fetus has not met these epitopes at proper time during intrauterine development, the consequence is that the negative selection of lymphocytes in the thymus and bone marrow and fetal liver is not perfect. When a child later in postnatal life becomes predisposed to ASiZn particles the immune system reacts to these as to nonself proteins. As a consequence the insulin producing beta cells are destroyed. Many observations from diabetes research support the hypothesis, some to mentioned. 1. Three common autoantigens (ZnT8, ICA512/IA-2, GAD65) are membrane proteins whose function zinc regulates. 2. Geographical variation in Finland is convergent with surface water manganese concentrations. Manganese is the principal Zn scavenger and high manganese in water reduces ASiZn particle formation and the incidence of T1D. 3. The incidence of T1D depends of drinking water pH. The highest incidence can be found within water pH 6.2-6.9. Zn coordination changes from octahedral (unphysiologic) to tetrahedral (physiologic) at pH 6.56. In the text are presented five more supporting observations e.g. the similarity between the soils in Sardinia and Finland in respect to ASi.

Islet inflammation in human type 1 diabetes mellitus

Type 1 diabetes mellitus (T1DM) is caused by the selective deletion of pancreatic β-cells in response to an assault mounted within the pancreas by infiltrating immune cells. However, this apparently clear and focussed annunciation conceals a stark reality in which the cellular and molecular events leading to β-cell loss remain poorly understood in humans. This reflects the difficulty of studying these processes in living individuals and the fact that, using pathological specimens, islet inflammation has been analysed in fewer than 200 recent-onset cases of T1DM worldwide, over the past century. Nevertheless, insights have been gained and the composition of the islet infiltrate is being disclosed. This is shown to be primarily lymphocytic in nature, with populations of both CD8+ and CD4+ T cells displaying an autoreactivity against specific islet antigenic peptides. The T cells are often accompanied by influent CD20+ B cells, although new data imply that the proportions of these individual cell types vary and that patients fall into at least two distinct categories having either a hyper-immune (CD20Hi) or a pauci-immune (CD20Lo) phenotype. The overall rate of β-cell decline appears to correlate with these two phenotypes such that hyper-immune patients lose β-cells more quickly and tend to develop disease at an earlier age than those with the pauci-immune profile. In this article, we review the evidence which underpins our current understanding of the aetiology of T1DM and highlight both the established features as well as areas of on-going ambiguity and debate.

Increased neutrophil elastase and proteinase 3 and augmented NETosis are closely associated with β-cell autoimmunity in patients with type 1 diabetes

Type 1 diabetes (T1D) is an autoimmune disease resulting from the self-destruction of insulin-producing β-cells. Reduced neutrophil counts have been observed in patients with T1D. However, the pathological roles of neutrophils in the development of T1D remain unknown. Here we show that circulating protein levels and enzymatic activities of neutrophil elastase (NE) and proteinase 3 (PR3), both of which are neutrophil serine proteases stored in neutrophil primary granules, were markedly elevated in patients with T1D, especially those with disease duration of less than 1 year. Furthermore, circulating NE and PR3 levels increased progressively with the increase of the positive numbers and titers of the autoantibodies against β-cell antigens. An obvious elevation of NE and PR3 was detected even in those autoantibody-negative patients. Increased NE and PR3 in T1D patients are closely associated with elevated formation of neutrophil extracellular traps. By contrast, the circulating levels of α1-antitrypsin, an endogenous inhibitor of neutrophil serine proteases, are decreased in T1D patients. These findings support an early role of neutrophil activation and augmented neutrophil serine proteases activities in the pathogenesis of β-cell autoimmunity and also suggest that circulating NE and PR3 may serve as sensitive biomarkers for the diagnosis of T1D.

Mechanistic evidence in support of alpha1-antitrypsin as a therapeutic approach for type 1 diabetes

Utilizing endogenous molecules as a therapeutic approach is almost unequivocally superior to engineered or synthetic molecules. However, one rarely encounters an anti-inflammatory, cytoprotective, immunomodulatory and wound-healing molecule that has been available for use for decades. α1-antitrypsin (AAT), a circulating protein that rises more than 4-fold during acute-phase responses, has been administered for a rare genetic deficiency at large doses, for life. Aside from advances in insulin therapy, medical research in type 1 diabetes (T1D) has predominantly focused on autoimmunity--controlling the adaptive immune response. However, it is now appreciated that one may need to extend therapeutic targets to incorporate immune responses to cellular injury, as well as promote selective control over excessive inflammation and early tissue repair. Recent data suggest that tissue damage related to lung and renal ischemia-reperfusion injury, stroke, and ischemic heart disease is markedly reduced by AAT. AAT was also shown to protect pancreatic islet β cells at multiple levels. Unlike classic immunosuppressive and anti-inflammatory approaches, AAT exerts some antiviral and antibacterial activities. Based on these and other reports, AAT is under evaluation for treatment of T1D patients in multiple clinical trials. Initial results suggest that AAT therapy could potentially improve insulin production without adverse effects. Up to 50% of individuals displayed improved islet function. It is a rare occurrence in T1D research that a therapy is offered that holds a safety profile equal or superior to that of insulin alone. While placebo-controlled trials are ongoing, the mechanism(s) behind these favorable activities of AAT are still being explored.

Diabetes recovery by age-dependent conversion of pancreatic δ-cells into insulin producers

Total or near-total loss of insulin-producing β-cells occurs in type 1 diabetes. Restoration of insulin production in type 1 diabetes is thus a major medical challenge. We previously observed in mice in which β-cells are completely ablated that the pancreas reconstitutes new insulin-producing cells in the absence of autoimmunity. The process involves the contribution of islet non-β-cells; specifically, glucagon-producing α-cells begin producing insulin by a process of reprogramming (transdifferentiation) without proliferation. Here we show the influence of age on β-cell reconstitution from heterologous islet cells after near-total β-cell loss in mice. We found that senescence does not alter α-cell plasticity: α-cells can reprogram to produce insulin from puberty through to adulthood, and also in aged individuals, even a long time after β-cell loss. In contrast, before puberty there is no detectable α-cell conversion, although β-cell reconstitution after injury is more efficient, always leading to diabetes recovery. This process occurs through a newly discovered mechanism: the spontaneous en masse reprogramming of somatostatin-producing δ-cells. The juveniles display 'somatostatin-to-insulin' δ-cell conversion, involving dedifferentiation, proliferation and re-expression of islet developmental regulators. This juvenile adaptability relies, at least in part, upon the combined action of FoxO1 and downstream effectors. Restoration of insulin producing-cells from non-β-cell origins is thus enabled throughout life via δ- or α-cell spontaneous reprogramming. A landscape with multiple intra-islet cell interconversion events is emerging, offering new perspectives for therapy.

Anterior pituitary autoantibodies in patients with type 1 diabetes mellitus: methodological problems and clinical correlations

BACKGROUND

Anti-pituitary antibodies (APA) were described in patients with Type 1 Diabetes (T1D) but their prevalence and relevance remain controversial.

MATERIALS AND METHODS

We evaluated the APA prevalence in Sardinian sera from 100 T1D patients, 70 Type 2 Diabetes (T2D) patients and 62 healthy controls, using indirect immunofluorescence on bovine pituitary sections. To compare two different substrates, we tested using bovine sections, further T1D patient sera (n = 11, from Pisa) previously analysed for APA on monkey sections, while some T1D Sardinian patient sera (n = 22) were tested on monkey sections. According to preliminary experiments, positivity were considered ≥1:200 and ≥1:20 for bovine and monkey substrates, respectively.

RESULTS AND DISCUSSION

Using bovine sections, APA were detected in 7/100 Sardinian T1D patients (at 1:200 titer) and in none of the other Sardinian sera tested. When the T1D sera from Pisa were tested on bovine and the T1D Sardinian sera were tested on monkey, none of these sera showed corresponding positivity for APA. Pituitary hormone dysfunctions were not found in the 7 APA-positive Sardinian T1D patients. The present study shows that the presence of APA at low-titer is highly related to T1D but not associated with any pituitary dysfunction while the animal species used as substrate appears crucial.

CONCLUSION

Further studies are needed to ascertain whether APA detected by different animal species may have different pathological relevance in T1D and/or whether APA in the long run may predict future anterior pituitary dysfunction.

Leukocyte profiles differ between type 1 and type 2 diabetes and are associated with metabolic phenotypes: results from the German Diabetes Study (GDS)

OBJECTIVE

Altered immune reactivity precedes and accompanies type 1 and type 2 diabetes. We hypothesized that the metabolic phenotype relates to the systemic cellular immune status.

RESEARCH DESIGN AND METHODS

A total of 194 metabolically well-controlled patients with type 1 diabetes (n = 62, mean diabetes duration 1.29 years) or type 2 diabetes (n = 132, 1.98 years) and 60 normoglycemic persons underwent blood sampling for automated white blood cell counting (WBC) and flow cytometry. Whole-body insulin sensitivity was measured with hyperinsulinemic-euglycemic clamp tests.

RESULTS

Patients with type 2 diabetes had higher WBC counts than control subjects along with a higher percentage of T cells and activated T helper (Th) and cytotoxic T (Tc) cells but lower proportions of natural killer (NK) cells. In type 1 diabetes, the percentage of activated Th and Tc cells was also higher compared with control subjects, whereas the ratio of regulatory T (Treg) cells to activated Th cells was lower, suggesting diminished regulatory capacity. Parameters of glycemic control related positively to Treg cells only in type 2 diabetes. Upon age, sex, and body mass adjustments, insulin sensitivity correlated positively with monocytes, while circulating lipids correlated positively with T cell subsets in type 1 diabetes.

CONCLUSIONS

Immune cell phenotypes showed distinct frequencies of occurrence in both diabetes types and associate with insulin sensitivity, glycemia, and lipidemia.

Role of epigenetic mechanisms in the development of chronic complications of diabetes

There is growing evidence that epigenetic regulation of gene expression including post-translational histone modifications (PTHMs), DNA methylation and microRNA (miRNA)-regulation of mRNA translation could play a crucial role in the development of chronic, diabetic complications. Hyperglycemia can induce an abnormal action of PTHMs and DNA methyltransferases as well as alter the levels of numerous miRNAs in endothelial cells, vascular smooth muscle cells, cardiomyocytes, retina, and renal cells. These epigenetic abnormalities result in changes in the expression of numerous genes contributing to effects such as development of chronic inflammation, impaired clearance of reactive oxygen species (ROS), endothelial cell dysfunction and/or the accumulation of extracellular matrix in the kidney, which causing the development of retinopathy, nephropathy or cardiomyopathy. Some epigenetic modifications, for example PTHMs and DNA methylation, become irreversible over time. Therefore, these processes have gained much attention in explaining the long-lasting detrimental consequences of hyperglycaemia causing the development of chronic complications even after improved glycaemic control is achieved. Our review suggests that the treatment of chronic complications should focus on erasing metabolic memory by targeting chromatin modification enzymes and by restoring miRNA levels.

Microbiome manipulation modifies sex-specific risk for autoimmunity

Despite growing evidence for a causal role of environmental factors in autoimmune diseases including the rise in disease frequencies over the past several decades we lack an understanding of how particular environmental exposures modify disease risk. In addition, many autoimmune diseases display sex-biased incidence, with females being disproportionately affected but the mechanisms underlying this sex bias remain elusive. Emerging evidence suggests that both host metabolism and immune function is crucially regulated by the intestinal microbiome. Recently, we showed that in the non-obese diabetic (NOD) mouse model of Type 1 Diabetes (T1D), the gut commensal microbial community strongly impacts the pronounced sex bias in T1D risk by controlling serum testosterone and metabolic phenotypes (1). Here we present new data in the NOD model that explores the correlations between microbial phylogeny, testosterone levels, and metabolic phenotypes, and discuss the future of microbiome-centered analysis and microbe-based therapeutic approaches in autoimmune diseases.

Beyond genetics. Influence of dietary factors and gut microbiota on type 1 diabetes

Type 1 diabetes (T1D) is an autoimmune disease ultimately leading to destruction of insulin secreting β-cells in the pancreas. Genetic susceptibility plays an important role in T1D etiology, but even mono-zygotic twins only have a concordance rate of around 50%, underlining that other factors than purely genetic are involved in disease development. Here we review the influence of dietary and environmental factors on T1D development in humans as well as animal models. Even though data are still inconclusive, there are strong indications that gut microbiota dysbiosis plays an important role in T1D development and evidence from animal models suggests that gut microbiota manipulation might prove valuable in future prevention of T1D in genetically susceptible individuals.

Role of viruses and other microbes in the pathogenesis of type 1 diabetes

Type 1 diabetes is caused by an immune-mediated destruction of insulin producing beta-cells in the pancreas. The risk of the disease is determined by interactions between more than 40 different susceptibility genes and yet unidentified environmental factors. The rapidly increasing incidence indicates that these environmental agents have a significant role in the pathogenesis. Microbes have associated with both increased and decreased risk reflecting their possible role as risk or protective factors. Two main hypotheses have been proposed to explain these effects: the hygiene hypothesis suggests that microbial exposures in early childhood stimulate immunoregulatory mechanisms which control autoimmune reactions (analogy with allergy), while the triggering hypothesis suggests that specific microbes damage insulin producing cells. Certain viruses, particularly enteroviruses, are currently the main candidates for such risk microbes. Enteroviruses cause diabetes in animals and have associated with increased risk of type 1 diabetes in epidemiological studies. They have also been detected in the pancreas of diabetic patients. Possible protective effect of microbes has been studied in animal models and in epidemiological studies, where certain enteral microbes (e.g. hepatitis A virus and Helicobacter pylori) and patterns of gut microbiome have associated with low risk of type 1 diabetes. In conclusion, these microbial effects offer attractive possibilities for the development of preventive interventions for type 1 diabetes based on the elimination of triggering agents (e.g. enterovirus vaccines) or use of protective microbes as probiotics.

Mechanisms of toxicity by proinflammatory cytokines in a novel human pancreatic beta cell line, 1.1B4

BACKGROUND

Molecular mechanisms of toxicity and cell damage were investigated in the novel human beta cell line, 1.1B4, after exposure to proinflammatory cytokines - IL-1β, IFN-γ, TNF-α.

METHODS

MTT assay, insulin radioimmunoassay, glucokinase assay, real time reverse transcription PCR, western blotting, nitrite assay, caspase assay and comet assay were used to investigate mechanisms of cytokine toxicity.

RESULTS

Viability of 1.1B4 cells decreased after 18h cytokine exposure. Cytokines significantly reduced cellular insulin content and impaired insulin secretion induced by glucose, alanine, KCl, elevated Ca(2+), GLP-1 or forskolin. Glucokinase enzyme activity, regulation of intracellular Ca(2+) and PDX1 protein expression were significantly reduced by cytokines. mRNA expression of genes involved in secretory function - INS, GCK, PCSK2 and GJA1 was downregulated in cytokine treated 1.1B4 cells. Upregulation of transcription of genes involved in antioxidant defence - SOD2 and GPX1 was observed, suggesting involvement of oxidative stress. Cytokines also upregulated transcriptions of NFKB1 and STAT1, which was accompanied by a significant increase in NOS2 transcription and accumulation of nitrite in culture medium, implicating nitrosative stress. Oxidative and nitrosative stresses induced apoptosis was evident from increased % tail DNA, DNA fragmentation, caspase 3/7 activity, apoptotic cells and lower BCL2 protein expression.

CONCLUSIONS

This study delineates molecular mechanisms of cytokine toxicity in 1.1B4 cells, which agree with earlier observations using human islets and rodent beta cells.

GENERAL SIGNIFICANCE

This study emphasizes the potential usefulness of this cell line as a human beta cell model for research investigating autoimmune destruction of pancreatic beta cells.

The prediction of type 1 diabetes by multiple autoantibody levels and their incorporation into an autoantibody risk score in relatives of type 1 diabetic patients

OBJECTIVE

We assessed whether a risk score that incorporates levels of multiple islet autoantibodies could enhance the prediction of type 1 diabetes (T1D).

RESEARCH DESIGN AND METHODS

TrialNet Natural History Study participants (n = 784) were tested for three autoantibodies (GADA, IA-2A, and mIAA) at their initial screening. Samples from those positive for at least one autoantibody were subsequently tested for ICA and ZnT8A. An autoantibody risk score (ABRS) was developed from a proportional hazards model that combined autoantibody levels from each autoantibody along with their designations of positivity and negativity.

RESULTS

The ABRS was strongly predictive of T1D (hazard ratio [with 95% CI] 2.72 [2.23-3.31], P < 0.001). Receiver operating characteristic curve areas (with 95% CI) for the ABRS revealed good predictability (0.84 [0.78-0.90] at 2 years, 0.81 [0.74-0.89] at 3 years, P < 0.001 for both). The composite of levels from the five autoantibodies was predictive of T1D before and after an adjustment for the positivity or negativity of autoantibodies (P < 0.001). The findings were almost identical when ICA was excluded from the risk score model. The combination of the ABRS and the previously validated Diabetes Prevention Trial-Type 1 Risk Score (DPTRS) predicted T1D more accurately (0.93 [0.88-0.98] at 2 years, 0.91 [0.83-0.99] at 3 years) than either the DPTRS or the ABRS alone (P ≤ 0.01 for all comparisons).

CONCLUSIONS

These findings show the importance of considering autoantibody levels in assessing the risk of T1D. Moreover, levels of multiple autoantibodies can be incorporated into an ABRS that accurately predicts T1D.

Intrafamilial spread of enterovirus infections at the clinical onset of type 1 diabetes

BACKGROUND

At the clinical onset of type 1 diabetes mellitus (T1D), enterovirus (EV) infections are suspected to play a role. EVs in blood are seen as a possible biomarker of T1D. EV infections may occur in temporal and geographic clusters and may spread within families.

OBJECTIVE

We checked whether EVs were present in the blood of newly diagnosed diabetic probands and of their consenting siblings and parents. We aimed at evaluating the frequency of EV infection, whether infections were spreading within families, and which EV species were involved.

SUBJECTS AND METHODS

Blood was drawn from 24 newly diagnosed diabetic children/adolescents and their family members (20 siblings and 41 parents). Blood donors and non-diabetic children/adolescents diagnosed with overweight/short stature were used as controls. RNA was extracted from plasma/leukocytes. Reverse-transcription polymerase chain reaction assays capable of detecting virtually all EV types and of giving preliminary species identification were used.

RESULTS AND CONCLUSIONS

EV genomes were found in the blood of 19 of 24 (79%) diabetics, 12 of 20 (60%) non-diabetic siblings, 26 of 41 (63%) parents, and 1 of 29 (3%) pediatric controls. EVs of the A, B, C, and D species were detected, with the B and C species more prevalent. Probands and virus-positive members of each family consistently shared the same EV species. During follow-up, 4 of 20 (20%) siblings of diabetic probands developed T1D with a latency of 3-25 months. In conclusion, infection by different EV species is highly prevalent at the clinical onset and extends to family members. EV may represent a precipitating factor of T1D. However, the disease only develops in a subset of infected individuals.