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Introduction: Proinflammatory cytokines are implicated in pancreatic ß cell failure in type 1 and type 2 diabetes and are known to stimulate alternative RNA splicing and the expression of nonsense-mediated RNA decay (NMD) components. Here, we investigate whether cytokines regulate NMD activity and identify transcript isoforms targeted in ß cells., Methods: A luciferase-based NMD reporter transiently expressed in rat INS1(832/13), human-derived EndoC-ßH3, or dispersed human islet cells is used to examine the effect of proinflammatory cytokines (Cyt) on NMD activity. The gain- or loss-of-function of two key NMD components, UPF3B and UPF2, is used to reveal the effect of cytokines on cell viability and function. RNA-sequencing and siRNA-mediated silencing are deployed using standard techniques., Results: Cyt attenuate NMD activity in insulin-producing cell lines and primary human ß cells. These effects are found to involve ER stress and are associated with the downregulation of UPF3B. Increases or decreases in NMD activity achieved by UPF3B overexpression (OE) or UPF2 silencing raise or lower Cyt-induced cell death, respectively, in EndoC-ßH3 cells and are associated with decreased or increased insulin content, respectively. No effects of these manipulations are observed on glucose-stimulated insulin secretion. Transcriptomic analysis reveals that Cyt increases alternative splicing (AS)-induced exon skipping in the transcript isoforms, and this is potentiated by UPF2 silencing. Gene enrichment analysis identifies transcripts regulated by UPF2 silencing whose proteins are localized and/or functional in the extracellular matrix (ECM), including the serine protease inhibitor SERPINA1/α-1-antitrypsin, whose silencing sensitizes ß-cells to Cyt cytotoxicity. Cytokines suppress NMD activity via UPR signaling, potentially serving as a protective response against Cyt-induced NMD component expression., Conclusion: Our findings highlight the central importance of RNA turnover in ß cell responses to inflammatory stress., Competing Interests: Author GR is a consultant for, and has received grant funding from, Sun Pharmaceuticals Inc. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The author(s) declared that they were an editorial board member of Frontiers, at the time of submission. This had no impact on the peer review process and the final decision., (Copyright © 2024 Ghiasi, Marchetti, Piemonti, Nielsen, Porse, Mandrup-Poulsen and Rutter.)

Voltage-gated potassium (K v ) channels play an important role in the repolarization of a variety of excitable tissues, including in the cardiomyocyte and the pancreatic beta cell. Recently, individuals carrying loss-of-function (LoF) mutations in KCNQ1, encoding K v 7.1, and KCNH2 (hERG), encoding K v 11.1, were found to exhibit post-prandial hyperinsulinaemia and episodes of hypoglycaemia. These LoF mutations also cause the cardiac disorder long QT syndrome (LQTS), which can be aggravated by hypoglycaemia. Interestingly, patients with LQTS also have a higher burden of diabetes compared to the background population, an apparent paradox in relation to the hyperinsulinaemic phenotype, and KCNQ1 has been identified as a type 2 diabetes risk gene. This review article summarizes the involvement of delayed rectifier K + channels in pancreatic beta cell function, with emphasis on K v 7.1 and K v 11.1, using the cardiomyocyte for context. The functional and clinical consequences of LoF mutations and polymorphisms in these channels on blood glucose homeostasis are explored using evidence from pre-clinical, clinical and genome-wide association studies, thereby evaluating the link between LQTS, hyperinsulinaemia and type 2 diabetes., (© 2022 The Authors. Acta Physiologica published by John Wiley & Sons Ltd on behalf of Scandinavian Physiological Society.)

Proinsulin is a misfolding-prone protein, and its efficient breakdown is critical when β-cells are confronted with high-insulin biosynthetic demands, to prevent endoplasmic reticulum stress, a key trigger of secretory dysfunction and, if uncompensated, apoptosis. Proinsulin degradation is thought to be performed by the constitutively expressed standard proteasome, while the roles of other proteasomes are unknown. We recently demonstrated that deficiency of the proinsulin chaperone glucose-regulated protein 94 (GRP94) causes impaired proinsulin handling and defective insulin secretion associated with a compensated endoplasmic reticulum stress response. Taking advantage of this model of restricted folding capacity, we investigated the role of different proteasomes in proinsulin degradation, reasoning that insulin secretory dynamics require an inducible protein degradation system. We show that the expression of only one enzymatically active proteasome subunit, namely, the inducible β5i-subunit, was increased in GRP94 CRISPR/Cas9 knockout (KO) cells. Additionally, the level of β5i-containing intermediate proteasomes was significantly increased in these cells, as was β5i-related chymotrypsin-like activity. Moreover, proinsulin levels were restored in GRP94 KO upon β5i small interfering RNA-mediated knockdown. Finally, the fraction of β-cells expressing the β5i-subunit is increased in human islets from type 2 diabetes patients. We conclude that β5i is an inducible proteasome subunit dedicated to the degradation of mishandled proinsulin.

Type 1 and type 2 diabetes are characterized by chronic inflammation; both diseases involve pancreatic islet inflammation, while systemic low-grade inflammation is a feature of obesity and type 2 diabetes. Long-term activation of the innate immune system impairs insulin secretion and action, and inflammation also contributes to macrovascular and microvascular complications of diabetes. However, despite strong preclinical evidence and proof-of-principle clinical trials demonstrating that targeting inflammatory pathways can prevent cardiovascular disease and other complications in patients with diabetes, there are still no approved treatments for diabetes that target innate immune mediators. Here, we review recent advances in our understanding of the inflammatory pathogenesis of type 1 and type 2 diabetes from a translational angle and point out the critical gaps in knowledge that need to be addressed to guide drug development.

With obesity and type 2 diabetes prevalence steadily increasing and no effective means in sight to support the population in obtaining and maintaining stable weight loss, there is an imminent need for pharmacological therapy to treat and prevent type 2 diabetes. Current anti-diabetic treatment is symptomatic, and very few drugs have both a strong preclinical rationale and clinical proof-of-principle as therapies targeting pathogenic processes in type 2 diabetes. The emerging appreciation of low-grade inflammation as a significant cause of insulin resistance and beta cell failure warrants exploring anti-inflammatory compounds as drug candidates. Since recent studies have demonstrated considerable phenotypic heterogeneity in the type 2 diabetic syndrome, the concept of one drug fits all is naïve, and biomarkers for the selection of type 2 diabetes subtypes for differentiated treatment based on genetic and pathogenic stratification are urgently needed. Biologics antagonizing the master pro-inflammatory cytokine interleukin-1 is one of the few principles specifically targeting low-grade inflammation in type 2 diabetes. Although early phase II studies were encouraging, subsequent underpowered studies and phase III studies designed primarily with cardiovascular endpoints have discredited the potential of anti-interleukin-1 approaches to treat the subgroup of patients that may benefit from this treatment. In this meta-analysis of 2921 individuals from eight phase I-IV studies, we demonstrate a significant overall HbA1c-lowering effect of interleukin-1 antagonism. Meta-regression analyses demonstrated a significant correlation between baseline C-reactive protein and C-peptide, and HbA1c outcome. The identification of further biomarkers for future clinical trials to define the potential of anti-interleukin-1 therapies in type 2 diabetes is urgently needed.

Background: The haemoglobin glycation index (HGI) has been proposed as a marker of interindividual differences in haemoglobin glycosylation. Previous studies have shown a relationship between high HGI and risk of cardiovascular disease (CVD) in patients with diabetes. However, no studies have investigated the role of previous CVD in this association., Methods: The study cohort comprised patients with type 2 diabetes mellitus (T2DM; n=1910) included in the Second Manifestations of Arterial Disease (SMART) study. The relationship between either HGI or HbA 1c and a composite of cardiovascular events as the primary outcome, and mortality, cardiovascular mortality, myocardial infarction and stroke as secondary outcomes, was investigated using Cox proportional-hazards models. Similar analyses were performed after stratification according to previous CVD., Results: A 1-unit higher HGI was associated with a 29% greater risk of a composite of cardiovascular events (HR: 1.29, 95% CI: 1.06-1.57) in patients without previous CVD, whereas no such relationship was seen in patients with previous CVD (HR: 0.96, 95% CI: 0.86-1.08). The direction and magnitude of the hazard ratios (HRs) of HGI and HbA 1c in relation to outcomes were similar. Additional adjustment for HbA 1c in the association between HGI and outcomes lowered the HRs., Conclusion: Similar to HbA 1c , higher HGI is related to higher risk of cardiovascular events in patients with T2DM without CVD. As HbA 1c has proved to be a comparable risk factor, and obtaining and interpreting the HGI is complicated, any additional benefit of applying the HGI in clinical settings is likely to be limited., (Copyright © 2018. Published by Elsevier Masson SAS.)

The relationship between RNA and DNA oxidation and pharmacological treatment has not been systematically investigated in patients with type 2 diabetes (T2D). We aimed to investigate the association between pharmacological treatments and levels of urinary markers of nucleic acid oxidation in T2D patients. Vejle Diabetes Biobank cohort data was nested into nationwide registry data. Multiple logistic regression was used to associate drug usage with risk of high (above median) RNA and DNA oxidation. Data from 2664 T2D patients (64% male, age range: 25-75) were included. Questionnaire-validated lipid lowering drug use was associated with low RNA oxidation (Odds ratio, OR 0.71, 95% CI: [0.59-0.87]). Insulin and non-specific antidiabetic drugs were associated with low DNA oxidation (insulin: OR 0.60, 95% CI [0.49-0.73]). Oral antidiabetics were associated with high DNA oxidation and RNA oxidation (OR 1.30, 95% CI [1.10-1.53] and OR 1.26, 95% CI [1.07-1.29]). Our findings indicate that diabetes-related drugs are associated with RNA and DNA oxidation and further studies are required to determine causality in T2D patients.

Although endoplasmic reticulum (ER) chaperone binding to mutant proinsulin has been reported, the role of protein chaperones in the handling of wild-type proinsulin is underinvestigated. Here, we have explored the importance of glucose-regulated protein 94 (GRP94), a prominent ER chaperone known to fold insulin-like growth factors, in proinsulin handling within β-cells. We found that GRP94 coimmunoprecipitated with proinsulin and that inhibition of GRP94 function and/or expression reduced glucose-dependent insulin secretion, shortened proinsulin half-life, and lowered intracellular proinsulin and insulin levels. This phenotype was accompanied by post-ER proinsulin misprocessing and higher numbers of enlarged insulin granules that contained amorphic material with reduced immunogold staining for mature insulin. Insulin granule exocytosis was accelerated twofold, but the secreted insulin had diminished bioactivity. Moreover, GRP94 knockdown or knockout in β-cells selectively activated protein kinase R-like endoplasmic reticulum kinase (PERK), without increasing apoptosis levels. Finally, GRP94 mRNA was overexpressed in islets from patients with type 2 diabetes. We conclude that GRP94 is a chaperone crucial for proinsulin handling and insulin secretion., (© 2019 by the American Diabetes Association.)

Objective: Cardiovascular mortality risk remains high among patients with type 2 diabetes. Oxidative stress indicated by high urinary excretion of the biomarker for RNA oxidation, 8-oxo-7,8-dihydroguanosine (8-oxoGuo), is associated with an increased risk of death in newly diagnosed and treated patients. We assessed whether 8-oxoGuo is associated with specific cardiovascular and all-cause mortality risk., Research Design and Methods: Urinary biomarkers for nucleic acid oxidation were measured in a cohort of patients with type 2 diabetes aged ≥60 years ( n = 1,863), along with biochemical measurements, questionnaire findings, and Central Person Registry information to estimate the hazard ratios (HRs) for log2-transformed RNA oxidation using Cox regression., Results: During the 5-year follow-up, 173 of 1,863 patients had died (9.3%), including 73 patients who died of cardiovascular disease (42.2%). Doubling of RNA oxidation was associated with an HR of all-cause mortality of 2.10 (95% CI 1.63-2.71; P < 0.001) and an HR of cardiovascular death of 1.82 (95% CI 1.20-2.77; P = 0.005) after multiple adjustments. The 5-year absolute risks (ARs) of all-cause mortality (AR 13.9 [95% CI 10.8-17.0] vs. AR 6.10 [95% CI 4.00-8.30]) and cardiovascular mortality (AR 5.49 [95% CI 3.44-7.55] vs. AR 3.16 [95% CI 1.59-4.73]) were approximately two times higher in the highest quartile of RNA oxidation than in the lowest quartile., Conclusions: We conclude that high RNA oxidation is associated with all-cause and cardiovascular mortality risk in patients with type 2 diabetes. Targeting oxidative stress via interventions with long-term follow-up may reveal the predictive potential of the biomarker 8-oxoGuo., (© 2017 by the American Diabetes Association.)

In the last decade, there has been an explosion in both the number of and knowledge about miRNAs associated with both type 1 and type 2 diabetes. Even though we are presently in the initial stages of understanding how this novel class of posttranscriptional regulators are involved in diabetes, recent studies have demonstrated that miRNAs are important regulators of the islet transcriptome, controlling apoptosis, differentiation and proliferation, as well as regulating unique islet and beta-cell functions and pathways such as insulin expression, processing and secretion. Furthermore, a large number of miRNAs have been linked to diabetogenic processes induced by elevated levels of glucose, free fatty acids and inflammatory cytokines. Thus, miRNAs are novel therapeutic targets with the potential of protecting the beta-cell, and there is proof of principle that miRNA antagonists, so-called antagomirs, are effective in vivo for other disorders. miRNAs are exported out of cells in exosomes, raising the intriguing possibility of cell-to-cell communication between distant tissues via miRNAs and that miRNAs can be used as biomarkers of beta-cell function, mass and survival. The purpose of this review is to provide a status on how miRNAs control beta-cell function and viability in health and disease., (Copyright © 2015 John Wiley & Sons, Ltd.)

Introduction: Diabetes is a currently incurable, epidemically growing global health concern. Contemporary symptomatic treatment targets acute and chronic metabolic consequences of relative or absolute insulin deficiency. Intensive multifactorial therapy is required to attenuate morbidity and mortality from late micro- and macrovascular complications, and despite current best clinical practice diabetes is still associated with shortened lifespan. There is an unmet need for interventions targeting pathogenetic mechanisms in diabetes, and the market for such therapies is huge., Areas Covered: Diabetes occurs when insulin secretion fails to meet tissue needs as a consequence of reduced functional beta-cell mass or reduced insulin sensitivity. Chronic inflammation contributes to beta-cell failure and insulin resistance. Molecular details are accumulating on the underlying cellular and molecular pathways. The testing of specific anti-inflammatory biologics targeting single pro-inflammatory cytokines has provided clinical proof-of-concept., Expert Opinion: IL-1 antagonists have so far failed to meet primary end points in recent-onset type 1 diabetes in Phase IIa, and promising Phase I and IIa trials in type 2 diabetes need confirmation in Phase III. The magnitude of response is variable and may relate to sub-phenotypes of these heterogeneous disorders. More studies are required to appreciate the potential of these drugs in diabetes.

The recent molecular, biologic, and genetic understanding of the inflammasome has revolutionized the diagnosis of and therapy for the phenotypically heterogeneous group of rare oligogenic disorders, now recognized to have autoinflammatory origin. This article reviews the importance of inflammasome activation in the central and peripheral mechanisms underlying a common, multifactorial, lifestyle-related, and polygenetic disease (type 2 diabetes mellitus), and conceptualizes the notion that this health challenge should now be recognized to have an autoinflammatory cause. It is hoped that targeting these mechanisms will enable the introduction of novel therapies that attack the basic pathogenetic mechanisms of type 2 diabetes mellitus rather than the epiphenomena that are its consequences., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Objective: Metabolic activation of the innate immune system governed by interleukin (IL)-1β contributes to β-cell failure in type 2 diabetes. Gevokizumab is a novel, human-engineered monoclonal anti-IL-1β antibody. We evaluated the safety and biological activity of gevokizumab in patients with type 2 diabetes., Research Design and Methods: In a placebo-controlled, dose-escalation study, a total of 98 patients were randomly assigned to placebo (17 subjects) or gevokizumab (81 subjects) at increasing doses and dosing schedules. The primary objective of the study was to evaluate the safety profile of gevokizumab in type 2 diabetes. The secondary objectives were to assess pharmacokinetics for different dose levels, routes of administration, and regimens and to assess biological activity., Results: The study drug was well tolerated with no serious adverse events. There was one hypoglycemic event whereupon concomitant insulin treatment had to be reduced. Clearance of gevokizumab was consistent with that for a human IgG(2), with a half-life of 22 days. In the combined intermediate-dose group (single doses of 0.03 and 0.1 mg/kg), the mean placebo-corrected decrease in glycated hemoglobin was 0.11, 0.44, and 0.85% after 1, 2 (P = 0.017), and 3 (P = 0.049) months, respectively, along with enhanced C-peptide secretion, increased insulin sensitivity, and a reduction in C-reactive protein and spontaneous and inducible cytokines., Conclusions: This novel IL-1β-neutralizing antibody improved glycemia, possibly via restored insulin production and action, and reduced inflammation in patients with type 2 diabetes. This therapeutic agent may be able to be used on a once-every-month or longer schedule.

Aims/hypothesis: Endothelial progenitor cells (EPC) augment vascular repair and neovascularisation. Patients with type 2 diabetes have reduced EPC and increased risk of cardiovascular disease (CVD), which is reduced by multifactorial intervention. Our aim, therefore, was to evaluate in type 2 diabetic patients whether the numbers of EPC derived from peripheral blood mononuclear cells is influenced by a multifactorial treatment strategy., Methods: We enrolled 28 patients newly referred for initiation of multifactorial treatment, which consisted of improving glycaemic, lipid and blood pressure control, as well as antithrombotic therapy and lifestyle modification. EPC count was assessed by in vitro cultures at baseline and after 90 days of treatment. After 7 days in culture, we identified EPC by fluorescent staining of attached cells. Patients were treated with metformin, aspirin, statins and angiotensin II receptor blockers, and divided accordingly into groups of mono-, dual-, triple- or quadruple therapy., Results: After 90 days of treatment, glycaemic control improved and total cholesterol decreased. Multifactorial intervention for 90 days significantly increased EPC count in cultures by 35% (from 105 [SE 8] to 140 [11] cells per field [p = 0.002]). The change in EPC among patients with quadruple therapy was higher (63%) than in untreated patients (-32%, p = 0.043)., Conclusions/interpretation: Numbers of EPC derived from peripheral blood mononuclear cells increased significantly after multifactorial intervention in type 2 diabetic patients. It remains to be shown whether these changes contribute to the beneficial effects of multifactorial intervention on diabetic micro- and macroangiopathy.

Purpose of Review: To understand the role of inflammation as the fundamental cause of type 2 diabetes and specifically to examine the contribution of IL-1beta., Recent Findings: Recent studies from animals, in-vitro cultures and clinical trials provide evidence that support a causative role for IL-1beta as the primary agonist in the loss of beta-cell mass in type 2 diabetes. In vitro, IL-1beta-mediated autoinflammatory process results in beta-cell death. The autoinflammation is driven by glucose, free fatty acids, leptin, and IL-1beta itself. Caspase-1 is required for IL-1beta activity and the release of free fatty acids from the adipocyte. An emerging hypothesis gains support from patients with type 2 diabetes in which an imbalance in the amount of IL-1beta agonist activity versus the specific countering by the naturally occurring IL-1 receptor antagonist (IL-1Ra) determines the outcome of islet inflammation. An important confirmation comes from clinical trials. Blockade of IL-1 receptor with anakinra, the recombinant form of IL-1Ra, or neutralizing anti-IL-1beta antibodies, provides proof-of-principle data that reducing IL-1beta activity is sufficient for correcting dysfunctional beta-cell production of insulin in type 2 diabetes, including a possibility that suppression of IL-1beta-mediated inflammation in the microenvironment of the islet allows for regeneration., Summary: Monotherapy or add-on therapy targeting IL-1beta in type 2 diabetes holds promise for long-term benefits in glycemic control and possibly reducing cardiovascular events.

Objective: Interleukin (IL)-1 impairs insulin secretion and induces beta-cell apoptosis. Pancreatic beta-cell IL-1 expression is increased and interleukin-1 receptor antagonist (IL-1Ra) expression reduced in patients with type 2 diabetes. Treatment with recombinant IL-1Ra improves glycemia and beta-cell function and reduces inflammatory markers in patients with type 2 diabetes. Here we investigated the durability of these responses., Research Design and Methods: Among 70 ambulatory patients who had type 2 diabetes, A1C >7.5%, and BMI >27 kg/m(2) and were randomly assigned to receive 13 weeks of anakinra, a recombinant human IL-1Ra, or placebo, 67 completed treatment and were included in this double-blind 39-week follow-up study. Primary outcome was change in beta-cell function after anakinra withdrawal. Analysis was done by intention to treat., Results: Thirty-nine weeks after anakinra withdrawal, the proinsulin-to-insulin (PI/I) ratio but not stimulated C-peptide remained improved (by -0.07 [95% CI -0.14 to -0.02], P = 0.011) compared with values in placebo-treated patients. Interestingly, a subgroup characterized by genetically determined low baseline IL-1Ra serum levels maintained the improved stimulated C-peptide obtained by 13 weeks of IL-1Ra treatment. Reductions in C-reactive protein (-3.2 mg/l [-6.2 to -1.1], P = 0.014) and in IL-6 (-1.4 ng/l [-2.6 to -0.3], P = 0.036) were maintained until the end of study., Conclusions: IL-1 blockade with anakinra induces improvement of the PI/I ratio and markers of systemic inflammation lasting 39 weeks after treatment withdrawal.

Background: We have previously reported that systemic blockade of IL-1beta in patients with type 2 diabetes with anakinra (a recombinant human interleukin-1-receptor antagonist, IL-1Ra), lowered glycated hemoglobin improved beta-cell function and reduced circulating levels of IL-6 and CRP (7). To investigate the effects of IL-1Ra in insulin-sensitive tissue, gene expression levels in skeletal muscle from type 2 diabetic patients treated with IL-1Ra were analysed., Methods: Gene expression profiles in vastus lateralis muscle biopsies from five obese patients (BMI >27) were determined before and after 13 weeks of treatment with IL-1Ra (anakinra) using Affymetrix U133Plus2.0 GeneChips. Microarray data were normalized and analysed independently using four different algorithms; RMA, GCRMA, dChip and GCOS. Hypothesis tests were applied to the microarray data for each gene, and protein network analysis was used to identify biological networks/pathways affected by the treatment. Gene expression levels for candidate genes (COL1A1, CDKN1C, HSP70, HLA-A, IL-1 and IL-6) were determined by qRT-PCR in muscles of placebo- (n = 12) and anakinra-treated patients (n = 11)., Results: The concordance of the variations of the transcripts identified as significantly regulated after IL-1Ra treatment was low. No significantly altered expression levels could be demonstrated after false discovery rate correction. The protein interaction network did not reveal any altered networks/pathways. None of the candidate genes, quantified by qRT-PCR, were significantly altered when comparing the number of transcripts before and after treatment for each individual. conclusion: Treatment with IL-1Ra did not significantly affect gene expression levels in skeletal muscle in this limited and selected sample of obese patients with type 2 diabetes. Larger studies might confirm the lack of effect of anakinra on muscle tissue gene expression.

Aims/hypothesis: The suppressor of cytokine signalling 1 (SOCS1) is a natural inhibitor of cytokine and insulin signalling pathways and may also play a role in obesity. In addition, SOCS1 is considered a candidate gene in the pathogenesis of both type 1 diabetes (T1D) and type 2 diabetes (T2D). The objective was to perform mutation analysis of SOCS1 and to test the identified variations for association to T2D-related quantitative traits, T2D or T1D., Methods: Mutation scanning was performed by direct sequencing in 27 white Danish subjects. Genotyping was carried out by TaqMan allelic discrimination. A total of more than 8100 individuals were genotyped., Results: Eight variations were identified in the 5' untranslated region (UTR) region. Two of these had allele frequencies below 1% and were not further examined. The six other variants were analysed in groups of T1D families (n = 1461 subjects) and T2D patients (n = 1430), glucose tolerant first-degree relatives of T2D patients (n = 212) and normal glucose tolerant (NGT) subjects. The rs33977706 polymorphism (-820G > T) was associated with a lower body mass index (BMI) (p = 0.004). In a second study (n = 4625 NGT subjects), significant associations of both the rs33977706 and the rs243330 (-1656G > A) variants to obesity were found (p = 0.047 and p = 0.015) respectively. The rs33977706 affected both binding of a nuclear protein to and the transcriptional activity of the SOCS1 promoter, indicating a relationship between this polymorphism and gene regulation., Conclusions/interpretation: This study demonstrates that functional variations in the SOCS1 promoter may associate with alterations in BMI in the general white population.

Biologic therapeutics are currently not approved for the treatment of patients with type 1 and type 2 diabetes. However, promising results from recent randomized controlled studies suggest that biologic therapeutics have therapeutic potential. This article summarizes the causal steps of the pathogenesis of type 1 and type 2 diabetes which are targeted by biologic therapeutics and reviews the treatment results.

The tale of cytokines and the beta-cell is a long story, starting with in vitro discovery in 1984, evolving via descriptive and phenomenological studies to detailed mapping of the signalling pathways, gene- and protein expression patterns, molecular and biochemical effector mechanisms to in vivo studies in spontaneously diabetic and transgenic animal models. Only very recently have steps been taken to translate the accumulating compelling preclinical data into clinical trials. The aim of this chapter is to present an overview of early and recent key observations from our own groups as well as other laboratories that serve to illuminate the road from concept to clinical translation.

Background: The expression of interleukin-1-receptor antagonist is reduced in pancreatic islets of patients with type 2 diabetes mellitus, and high glucose concentrations induce the production of interleukin-1beta in human pancreatic beta cells, leading to impaired insulin secretion, decreased cell proliferation, and apoptosis., Methods: In this double-blind, parallel-group trial involving 70 patients with type 2 diabetes, we randomly assigned 34 patients to receive 100 mg of anakinra (a recombinant human interleukin-1-receptor antagonist) subcutaneously once daily for 13 weeks and 36 patients to receive placebo. At baseline and at 13 weeks, all patients underwent an oral glucose-tolerance test, followed by an intravenous bolus of 0.3 g of glucose per kilogram of body weight, 0.5 mg of glucagon, and 5 g of arginine. In addition, 35 patients underwent a hyperinsulinemic-euglycemic clamp study. The primary end point was a change in the level of glycated hemoglobin, and secondary end points were changes in beta-cell function, insulin sensitivity, and inflammatory markers., Results: At 13 weeks, in the anakinra group, the glycated hemoglobin level was 0.46 percentage point lower than in the placebo group (P=0.03); C-peptide secretion was enhanced (P=0.05), and there were reductions in the ratio of proinsulin to insulin (P=0.005) and in levels of interleukin-6 (P<0.001) and C-reactive protein (P=0.002). Insulin resistance, insulin-regulated gene expression in skeletal muscle, serum adipokine levels, and the body-mass index were similar in the two study groups. Symptomatic hypoglycemia was not observed, and there were no apparent drug-related serious adverse events., Conclusions: The blockade of interleukin-1 with anakinra improved glycemia and beta-cell secretory function and reduced markers of systemic inflammation. (ClinicalTrials.gov number, NCT00303394 [ClinicalTrials.gov].)., (Copyright 2007 Massachusetts Medical Society.)

Type II diabetes is caused by a failure of the pancreatic beta-cells to compensate for insulin resistance leading to hyperglycaemia. There is evidence for an essential role of an increased beta-cell apoptosis in type II diabetes. High glucose concentrations induce IL-1beta production in human beta-cells, Fas expression and concomitant apoptosis owing to a constitutive expression of FasL. FASL and FAS map to loci linked to type II diabetes and estimates of insulin resistance, respectively. We have tested two functional promoter polymorphisms, FAS-670 G>A and FASL-844C>T as well as a microsatellite in the 3' UTR of FASL for association to type II diabetes in 549 type II diabetic patients and 525 normal-glucose-tolerant (NGT) control subjects. Furthermore, we have tested these polymorphisms for association to estimates of beta-cell function and insulin resistance in NGT subjects. We found significant association to type II diabetes for the allele distribution of the FASL microsatellite (P-value 0.02, Bonferroni corrected). The FAS-670G>A was associated with homeostasis model assessment insulin resistance index and body mass index (P-values 0.02 and 0.02). We conclude that polymorphisms of FASL and FAS associate with type II diabetes and estimates of insulin resistance in Danish white subjects.

Inflammatory mechanisms play a key role in the pathogenesis of type 1 diabetes. Individuals who progress to type 2 diabetes display features of low-grade inflammation years in advance of disease onset. This low-grade inflammation has been proposed to be involved in the pathogenetic processes causing type 2 diabetes. Mediators of inflammation such as tumor necrosis factor-alpha, interleukin (IL)-1beta, the IL-6 family of cytokines, IL-18, and certain chemokines have been proposed to be involved in the events causing both forms of diabetes. IL-6 has in addition to its immunoregulatory actions been proposed to affect glucose homeostasis and metabolism directly and indirectly by action on skeletal muscle cells, adipocytes, hepatocytes, pancreatic beta-cells, and neuroendocrine cells. Here we argue that IL-6 action-in part regulated by variance in the IL-6 and IL-6alpha receptor genes-contributes to, but is probably neither necessary nor sufficient for, the development of both type 1 and type 2 diabetes. Thus, the two types of diabetes are also in this respect less apart than apparent. However, the mechanisms are not clear, and we therefore propose future directions for studies in this field.

Subclinical, low-grade systemic inflammation has been observed in patients with type 2 diabetes and in those at increased risk of the disease. This may be more than an epiphenomenon. Alleles of genes encoding immune/inflammatory mediators are associated with the disease, and the two major environmental factors the contribute to the risk of type 2 diabetes-diet and physical activity-have a direct impact on levels of systemic immune mediators. In animal models, targeting of immune genes enhanced or suppressed the development of obesity or diabetes. Obesity is associated with the infiltration and proinflammatory activity of macrophages in adipose tissue, and immune mediators may be important regulators of insulin resistance, mitochondrial function, ectopic lipid storage and beta cell dysfunction or death. Intervention studies targeting these pathways would help to determine the contribution of an activated innate immune system to the development of type 2 diabetes.

Objective: To evaluate the perinatal outcome and the frequency of maternal complications in pregnancies of women with type 2 diabetes during 1996-2001., Research Design and Methods: Medical records of 61 consecutive singleton pregnancies in women with type 2 diabetes from 1996 to 2001 were studied. Pregnancy outcome was compared with that of pregnant women with type 1 diabetes during 1996-2000, the background population, and pregnant women with type 2 diabetes during 1980-1992 from the same department., Results: The perinatal mortality in pregnancies complicated by type 2 diabetes (4/61, 6.6%) was increased four- and ninefold, respectively, and the rate of major congenital malformations (4/60, 6.7%) was more than doubled, although not statistically significant, compared with type 1 diabetic pregnancies and the background population. The glycemic control was similar or better in women with type 2 diabetes compared with women with type 1 diabetes. Multivariate logistic regression analysis in the pooled group of pregnancies with pregestational diabetes from 1996 to 2001 showed that high HbA(1c) at admission and type 2 diabetes were independently associated with a serious adverse fetal outcome (perinatal mortality and/or major congenital malformations). The perinatal mortality and the rate of major congenital malformations in type 2 diabetic pregnancies have increased during the last decade., Conclusions: The perinatal outcome of pregnancies in women with type 2 diabetes during 1996-2001 is poor. It is worse than the outcome of pregnancies in women with type 1 diabetes and the background population in the same period, as well as in women with type 2 diabetes studied during 1982-1990.

Aims/hypothesis: Beta cell loss in Type 1 and Type 2 diabetes mellitus may result from apoptosis and necrosis induced by inflammatory mediators. The suppressor of cytokine signalling (SOCS)-3 is a natural inhibitor of cytokine signalling and also influences insulin signalling. SOCS3 could therefore be a candidate gene in the development of Type 1 and Type 2 diabetes mellitus., Methods: Mutation analysis of the SOCS3 gene was performed in 21 patients with Type 1 diabetes mellitus and in seven healthy subjects. An identified promoter variant was examined in (i) 250 families with Type 1 diabetic family members (1097 individuals); (ii) 212 glucose-tolerant first-degree relatives of Type 2 diabetic patients; and (iii) 370 population-based young, healthy subjects who were unrelated., Results: Three mutations were identified in the promoter region, but none in the coding region or the 3'UTR. Two of the three mutations had allele frequencies below 1% whereas the C -920-->A substitution had a minor allele frequency of 8%. In the group of young healthy subjects the insulin sensitivity index was higher among homozygous carriers of the A-allele than among heterozygous and wild-type subjects ( p=0.027, uncorrected). The same trend was found in the group of first-degree relatives of Type 2 diabetic patients. No association or linkage was found to Type 1 diabetes mellitus., Conclusions/interpretation: Homozygosity for the A-allele of the C -920-->A promoter polymorphism of the SOCS3 gene may be associated with increased whole-body insulin sensitivity, but deserves further investigation.

Failure of insulin producing pancreatic beta-cells is a common characteristic of type 1 (insulin-dependent) and type 2 (insulin non-dependent) diabetes mellitus. Accumulating evidence suggests that programmed cell death (apoptosis) is the main form of beta-cell death in these disorders. The beta-cell is particularly sensitive to apoptotic stimuli due to the inherent features of the specialized beta-cell phenotype. In type 1 diabetes anti-beta-cell autoimmune reactivity delivers the apoptotic signals in the form of inflammatory mediators or T-cell effectors. In type 2 diabetes, the metabolic derangement is associated with production of inflammatory mediators in insulin-sensitive tissues leading elevated levels of circulating inflammatory mediators such as IL-6 and TNF. Further glucose has been suggested to induce beta-cell apoptosis via the induction of beta-cell synthesis of IL-1 which via autocrine action may elicit signalling cascades analogous to those seen in beta-cell destruction in type 1 diabetes. Considering the apparent importance of IL-1-beta signalling in beta-cell failure in both type 1 and type 2 diabetes, we here review the modulatory effect exerted on IL-1signalling by cellular characteristics related to the specialized beta-cell phenotype. We conclude that beta-cell differentiation signals (Pdx-1), glucose metabolism, calcium handling as well as regulation of naturally occurring inhibitors of cytokine signalling contribute to sensitize the beta-cell to apoptotic stimuli. We hypothesize that immunological stimuli in type 1 diabetes and metabolic/inflammatory signals in type 2 diabetes converge on common signalling pathways leading to beta-cell failure and destruction in these two diseases.

Pancreatic islet beta-cell death occurs in type 1 and 2 diabetes mellitus, leading to absolute or relative insulin deficiency. beta-cell death in type 1 diabetes is due predominantly to autoimmunity. In type 2 diabetes beta-cell death occurs as the combined consequence of increased circulating glucose and saturated fatty acids together with adipocyte secreted factors and chronic activation of the innate immune system. In both diabetes types intra-islet inflammatory mediators seem to trigger a final common pathway leading to beta-cell apoptosis. Therefore anti-inflammatory therapeutic approaches designed to block beta-cell apoptosis could be a significant new development in type 1 and 2 diabetes.

Islet cell cytoplasmic antibodies were determined in 85 individuals 60 to 74 years old with fasting hyperglycaemia, in 65 patients with cystic fibrosis, in 113 patients with pancreatitis, in 21 patients with Turner's phenotype, and in 135 first-degree relatives of patients with Type 1 (insulin-dependent) diabetes. Islet cell antibodies were absent in all 60 to 74-year-old subjects with fasting hyperglycaemia detected by screening, and who did not require insulin treatment within 3 years. Islet cell antibodies were also absent in all patients with pancreatitis, cystic fibrosis, or Turner's phenotype. Islet cell antibodies were detected in 2 out of 135 (1.5%) first-degree relatives of new Type 1 diabetic patients, and in 1 out of 371 (0.3%) non-diabetic control subjects. During 12 years of follow-up 1 of the 2 first-degree relatives with islet cell antibodies and the only positive control developed Type 1 diabetes. It is suggested that islet cell antibodies are primarily associated with Type 1 diabetes and not with other disorders of glucose tolerance.