Association of immune mediators at diagnosis of Type 1 diabetes with later clinical remission

Approaches to Measuring Beta Cell Reserve and Defining Partial Clinical Remission in Paediatric Type 1 Diabetes

CONTEXT

Type 1 diabetes (T1D) results from the autoimmune T-cell mediated destruction of pancreatic beta cells leading to insufficient insulin secretion. At the time of diagnosis of T1D, there is residual beta cell function that declines over the subsequent months to years. Recent interventions have been approved to preserve beta cell function in evolving T1D.

OBJECTIVE

The aim of this review is to summarise the approaches used to assess residual beta cell function in evolving T1D, and to highlight potential future directions.

METHODS

Studies including subjects aged 0 to 18 years were included in this review. The following search terms were used; "(type 1 diabetes) and (partial remission)" and "(type 1 diabetes) and (honeymoon)". References of included studies were reviewed to determine if additional relevant studies were eligible.

RESULTS

There are numerous approaches to quantifying beta cell reserve in evolving T1D. These include c-peptide measurement after a mixed meal or glucagon stimuli, fasting c-peptide, the urinary c-peptide/creatinine ratio, insulin dose-adjusted haemoglobin A1c, and other clinical models to estimate beta cell function. Other biomarkers may have a role, including the proinsulin/c-peptide ratio, cytokines, and microRNA. Studies using thresholds to determine if residual beta cell function is present often differ in values used to define remission.

CONCLUSIONS

As interventions are approved to preserve beta cell function, it will become increasingly necessary to quantify residual beta cell function in research and clinical contexts. In this report, we have highlighted the strengths and limitations of the current approaches.

Immunoregulatory Biomarkers of the Remission Phase in Type 1 Diabetes: miR-30d-5p Modulates PD-1 Expression and Regulatory T Cell Expansion

The partial remission (PR) phase of type 1 diabetes (T1D) is an underexplored period characterized by endogenous insulin production and downmodulated autoimmunity. To comprehend the mechanisms behind this transitory phase and develop precision medicine strategies, biomarker discovery and patient stratification are unmet needs. MicroRNAs (miRNAs) are small RNA molecules that negatively regulate gene expression and modulate several biological processes, functioning as biomarkers for many diseases. Here, we identify and validate a unique miRNA signature during PR in pediatric patients with T1D by employing small RNA sequencing and RT-qPCR. These miRNAs were mainly related to the immune system, metabolism, stress, and apoptosis pathways. The implication in autoimmunity of the most dysregulated miRNA, miR-30d-5p, was evaluated in vivo in the non-obese diabetic mouse. MiR-30d-5p inhibition resulted in increased regulatory T cell percentages in the pancreatic lymph nodes together with a higher expression of CD200. In the spleen, a decrease in PD-1⁺ T lymphocytes and reduced PDCD1 expression were observed. Moreover, miR-30d-5p inhibition led to an increased islet leukocytic infiltrate and changes in both effector and memory T lymphocytes. In conclusion, the miRNA signature found during PR shows new putative biomarkers and highlights the immunomodulatory role of miR-30d-5p, elucidating the processes driving this phase.

The need and benefit of immune monitoring to define patient and disease heterogeneity, mechanisms of therapeutic action and efficacy of intervention therapy for precision medicine in type 1 diabetes

The current standard of care for type 1 diabetes patients is limited to treatment of the symptoms of the disease, insulin insufficiency and its complications, not its cause. Given the autoimmune nature of type 1 diabetes, immunology is critical to understand the mechanism of disease progression, patient and disease heterogeneity and therapeutic action. Immune monitoring offers the key to all this essential knowledge and is therefore indispensable, despite the challenges and costs associated. In this perspective, I attempt to make this case by providing evidence from the past to create a perspective for future trials and patient selection.

Influence of the occurrence and duration of partial remission on short-term metabolic control in type 1 diabetes: the DIABHONEY pediatric study

OBJECTIVE

To evaluate the residual effect of partial remission (PR) on immediate post-PR glycemic control according to its occurrence and duration in a cohort of children with type 1 diabetes mellitus (T1DM).

PATIENTS AND METHODS

Values of glycemic control parameters [i.e. HbA_1C, insulin dose-adjusted hemoglobin A_1C (IDAA_1C), glycemic target-adjusted HbA_1C (GTAA_1C)] and data from glucose monitoring devices from 189 pediatric patients with new-onset type 1 diabetes were collected retrospectively from 24 months. Patients were characterized according to their remission status (PR⁺ and PR^-). PR⁺ patients were subdivided into three subgroups regarding PR duration [i.e. short (⩾3-⩽6 months), intermediate (>6-⩽12 months), and long PR (>12-⩽14 months)]. We compared glycemic control data from each PR⁺ subgroup at +6 and +12 months post-PR with PR^- patients at the same postdiagnosis time. Second, PR⁺ subgroups were compared with each other.

RESULTS

PR⁺ patients showed improved glycemic control (i.e. HbA_1C, IDAA_1C, and GTAA_1C) at + 6 months post-PR when compared with nonremitters (PR^-), independently of the PR duration subgroups (p < 0.05). Interestingly, patients in long PR⁺ subgroup exhibited higher positive residual effect than short PR⁺ subgroup with lower GTAA_1C scores (p = 0.02), better time in range (TIR) (p = 0.003), less time in hypoglycemia (10.45 versus 16.13%, p = 0.03) and less glycemic variability (83.1 mg/dl versus 98.84 mg/dl, p = 0.03). No significant differences were found for glucose control between PR⁺ and PR^- patients at +12 months post-PR.

CONCLUSION

This study supports the positive impact of PR occurrence and duration on short-term metabolic control (better HbA_1C levels, IDAA_1C and GTAA_1C scores, TIR, and less glycemic variability) with the residual effect increasing according to PR duration.

Serum IL-1ra Is Associated with but Has No Genetic Link to Type 1 Diabetes

Interleukin-1 antagonism is a proposed biomarker and potential therapy for the delay and/or treatment of type 1 diabetes (T1D). We evaluated the role of circulating interleukin-1 receptor antagonist (IL-1ra) in a prospectively monitored cohort of T1D patients. In order to determine a mechanistic association between IL-1ra and T1D, we performed co-localization analyses between serum IL-1ra protein quantitative trait loci and T1D genome-wide analysis studies. Adjusting for human leukocyte antigen (HLA) genotypes, first degree relative status, gender, and age, serum levels of IL-1ra were lower in subjects who progressed to T1D compared to the controls (p = 0.023). Our results suggest that females have higher levels of IL-1ra compared to males (p = 0.005). The 2q14.1 region associated with serum IL-1ra levels is not associated with a risk of developing T1D. Our data suggest that IL-1 antagonism by IL-1ra is not an effective therapy in T1D, but IL-1ra may be a biomarker for progression to T1D.

Time in Range Assessed by Capillary Blood Glucose in Relation to Insulin Sensitivity and β-Cell Function in Patients with Type 2 Diabetes Mellitus: A Cross-Sectional Study in China

AIMS

This study investigated the association of capillary blood glucose (CBG)-assessed time in range (TIR) (3.9-10.0 mmol/L) with insulin sensitivity and islet β-cell function (BCF).

MATERIALS AND METHODS

We recruited 455 patients with type 2 diabetes mellitus. Seven-point glucose-profile data (pre- and 120-min post-main meals, bedtime) were collected over three consecutive days. Plasma glucose and serum insulin concentrations were measured at 0, 60, and 120 min after a 100-g standard steamed bread meal test. The homeostasis model assessment of insulin resistance (HOMA-IR) and Matsuda index were computed to evaluate insulin resistance (IR). HOMA of β-cell function (HOMA-β) and the area under the curve between insulin and blood glucose (IAUC_0-120 /GAUC_0-120 ) were used to estimate BCF.

RESULTS

TIR was positively correlated with 60- and 120-min insulin values, IAUC_0-120 , the Matsuda index, HOMA-β, and IAUC_0-120 /GAUC_0-120 (r_s : 0.154, 0.129, 0.137, 0.194, 0.341, and 0.334, respectively; P <0.05) but inversely correlated with HOMA-IR (r_s : -0.239, P <0.001). After adjusting for confounders, multinomial multiple logistic regression analysis revealed that the odds ratios (ORs) of achieving the target TIR (>70%) increased by 12% (95% confidence interval [CI]: 3-21%), 7% (95% CI: 1-14%), 10% (95% CI: 5-16%), and 45% (95% CI: 25-68%) for each 10-mIU/L increase in 60- and 120-min insulin value, 10-unit increase in HOMA-β, and unit increase in IAUC_0-120 /GAUC_0-120 , respectively (P <0.05). Nevertheless, the OR decreased by 10% (95% CI: 1-18%) for each unit increase in HOMA-IR (P <0.05).

CONCLUSIONS

IR and BCF are related to CBG-assessed TIR.

Identification of Sorafenib as a Treatment for Type 1 Diabetes

Th1 cell activation is considered a key mediator of the pathogenesis of type 1 diabetes. Targeting IL-12-induced Th1 cell differentiation seems to be an effective way to block the development of type 1 diabetes. However, given the critical function of Th1 in the immune system, the potential side effects hinder the application of anti-Th1 therapy in the treatment of type 1 diabetes. To identify safe anti-Th1 treatment(s), we screened the FDA-approved tyrosine kinase inhibitor (TKI) drug library using an IL-12-induced Th1 differentiation cell model. We found that among the TKIs with little effect on T cell viability, sorafenib is the top contender for the inhibition of Th1 differentiation. Treatment of NOD mice with sorafenib significantly impeded the development of type 1 diabetes and ameliorated insulitis, which coincided with a specifically decreased accumulation of Th1 cell population in the pancreas but not in peripheral immune organs. Mechanistically, sorafenib indirectly inhibited janus kinase 2 (JAK2) activity and blocked IL-12-induced phosphorylations of JAK2 and signal transducer and activator of transcription 4 (STAT4). Since sorafenib is classified as an FDA-approved drug, it serves as a preliminary lead point for additional experimentation and may be a promising therapy for type 1 diabetes in humans.

Candidate Biomarkers for the Prediction and Monitoring of Partial Remission in Pediatric Type 1 Diabetes

The partial remission (PR) phase, a period experienced by most patients with type 1 diabetes (T1D) soon after diagnosis, is characterized by low insulin requirements and improved glycemic control. Given the great potential of this phase as a therapeutic window for immunotherapies because of its association with immunoregulatory mechanisms and β-cell protection, our objective was to find peripheral immunological biomarkers for its better characterization, monitoring, and prediction. The longitudinal follow-up of 17 pediatric patients with new-onset T1D over one year revealed that, during the PR phase, remitter patients show increased percentages of effector memory (EM) T lymphocytes, terminally differentiated EM T lymphocytes, and neutrophils in comparison to non-remitter patients. On the contrary, remitter patients showed lower percentages of naïve T lymphocytes, regulatory T cells (T_REG), and dendritic cells (DCs). After a year of follow-up, these patients also presented increased levels of regulatory B cells and transitional T1 B lymphocytes. On the other hand, although none of the analyzed cytokines (IL-2, IL-6, TGF-β1, IL-17A, and IL-10) could distinguish or predict remission, IL-17A was increased at T1D diagnosis in comparison to control subjects, and remitter patients tended to maintain lower levels of this cytokine than non-remitters. Therefore, these potential monitoring immunological biomarkers of PR support that this stage is governed by both metabolic and immunological factors and suggest immunoregulatory attempts during this phase. Furthermore, since the percentage of T_REG, monocytes, and DCs, and the total daily insulin dose at diagnosis were found to be predictors of the PR phase, we next created an index-based predictive model comprising those immune cell percentages that could potentially predict remission at T1D onset. Although our preliminary study needs further validation, these candidate biomarkers could be useful for the immunological characterization of the PR phase, the stratification of patients with better disease prognosis, and a more personalized therapeutic management.

Genetic polymorphism of interleukin-1 receptor antagonist in Type 1 diabetic children

BACKGROUND

Interleukin-1 receptor antagonist (IL1RN) variable number tandem repeats (VNTRs) are not fully understood in Type 1 diabetes mellitus (T1DM). It may affect IL1RN level and modify the disease risk. We aimed to study IL1RN VNTR polymorphism in Egyptian children with T1DM to clarify its potential role as a risk factor for T1DM and its effect on plasma IL1RN level.

METHODS

A case-controlled study including 200 children (120 T1DM and 80 controls) was carried on. All children were subjected to genotyping of IL1RN VNTR. Plasma IL1RN was estimated by ELISA.

RESULTS

The A1A2 and LS genotypes and A2 allele were significantly higher among cases compared to controls with increased T1DM risk (OR = 5.35, 2.56 and 3.13, respectively). The S allele was significantly elevated in cases compared to controls with 2.09-fold increased risk of having T1DM. The median plasma IL1RN significantly decreased in cases compared to controls. Within cases, IL1RN was significantly decreased in LS versus LL genotype.

CONCLUSIONS

There is a strong relationship between IL1RN VNTR and T1DM in Egyptian children. A1A1 genotype, LL genotype, A1 allele, and L allele were protective. A1A2 and LS genotypes, short (S), and A2 alleles were risk factors. IL1RN was decreased in T1DM, especially in LS genotype.

IMPACT

The relationship between IL1RN gene polymorphism and risk for T1DM among Egyptian children. Plasma IL1RN protein level in T1DM. Low IL1RN protein level in T1DM patients could be therapeutic targets for IL1RN medications in the future.

Systemic TNFα correlates with residual β-cell function in children and adolescents newly diagnosed with type 1 diabetes

BACKGROUND

Type 1 diabetes (T1D) is caused by immune-mediated destruction of the β-cells. After initiation of insulin therapy many patients experience a period of improved residual β-cell function leading to partial disease remission. Cytokines are important immune-modulatory molecules and contribute to β-cell damage in T1D. The patterns of systemic circulating cytokines during T1D remission are not clear but may constitute biomarkers of disease status and progression. In this study, we investigated if the plasma levels of various pro- and anti-inflammatory cytokines around time of diagnosis were predictors of remission and residual β-cell function in children with T1D followed for one year after disease onset.

METHODS

In a cohort of 63 newly diagnosed children (33% females) with T1D with a mean age of 11.3 years (3.3-17.7), ten cytokines were measured of which eight were detectable in plasma samples by Mesoscale Discovery multiplex technology at study start and after 6 and 12 months. Linear regression models were used to evaluate association of cytokines with stimulated C-peptide.

RESULTS

Systemic levels of tumor necrosis factor (TNF)-α, interleukin (IL)-2 and IL-6 inversely correlated with stimulated C-peptide levels over the entire study (P < 0.05). The concentrations of TNFα and IL-10 at study start predicted stimulated C-peptide level at 6 months (P = 0.011 and P = 0.043, respectively, adjusted for sex, age, HbA1c and stage of puberty).

CONCLUSIONS

In recent-onset T1D, systemic cytokine levels, and in particular that of TNFα, correlate with residual β-cell function and may serve as prognostic biomarkers of disease remission and progression to optimize treatment strategies.

TRIAL REGISTRATION

The study was performed according to the criteria of the Helsinki II Declaration and was approved by the Danish Capital Region Ethics Committee on Biomedical Research Ethics (journal number H-3-2014-052). The parents of all participants gave written consent.

Clinical Remission of Type 1 Diabetes Predicts Higher Insulin Sensitivity at 7 Years from Diagnosis of the Disease

Background: Clinical remission of type 1 diabetes is not only associated with regeneration of beta cells and preserved insulin secretion but also with increased insulin sensitivity. The aim of the study was to determine the association between presence of remission in the first year of type 1 diabetes and insulin resistance at 7 years from diagnosis of the disease. Material and Methods: A total of 108 consecutive patients with newly diagnosed type 1 diabetes were followed prospectively. During the follow-up time, the onset and duration of clinical remission were registered. Seventy-four patients were included in the final analysis. Insulin sensitivity was assessed by the glucose disposal rate (GDR), determined using the hyperinsulinemic-euglycemic clamp, performed at 7 years from diagnosis of diabetes. Patients were divided into groups with GDR <4.5 mg/(kg·min) (G1-lower insulin sensitivity group) and GDR ≥4.5 mg/(kg·min) (G2-higher insulin sensitivity group). Results: Higher insulin sensitivity was observed in the remission group [GDR 6.2 interquartile range (IQR) 4.2-7.0 mg/(kg·min) vs. 3.8 (IQR 3.0-4.8) mg/(kg·min); P = 0.01]. Furthermore, in G2 group, the duration of remission was longer than in G1 group: (351 [IQR 206-561] days vs. 70 [IQR 0-289] days; P = 0.002). Also, the GDR value correlated positively with duration of remission (r = 0.42; P = 0.002). In the multivariate logistic regression model, including age, sex, body mass index at diagnosis, and presence of remission, the remission period was independently associated with a higher GDR value (odds ratio 10.88; 95% confidence interval: 1.70-69.50; P = 0.009]. Conclusions: Patients with type 1 diabetes who entered remission at the beginning of the disease, despite its ending, have higher insulin sensitivity at 7 years after diagnosis of diabetes than nonremitters.

Influence of Age on Partial Clinical Remission among Children with Newly Diagnosed Type 1 Diabetes

Partial clinical remission (PCR) is a transitory period characterized by the residual endogenous insulin secretion following type 1 diabetes (T1D) diagnosis and introducing the insulin therapy. Scientific interest in PCR has been recently increasing, as this phase could be crucial to preserve functional beta cells after T1D onset, also taking advantage of new therapeutic opportunities. The aim of this study was to assess the frequency, duration and associated factors of PCR in children newly diagnosed with T1D. Our cohort study included 167 pediatric patients aged 13.8 ± 4.1 years. The association of clinical and laboratory factors with the occurrence and duration of PCR was evaluated via logistic regression and multivariable generalized linear model, respectively. PCR occurred in 63.5% of the examined patients. Patients who achieved the remission phase were significantly older, and they had lower daily insulin requirement compared with non-remitters. PCR was positively associated to body mass index (OR = 1.11; p = 0.032), pH value (OR 49.02; p = 0.003) and c-peptide levels (OR 12.8; p = 0.002). The average duration of PCR was 13.4 months, and older age at diagnosis was the only predictor factor. Two years after diagnosis remitter patients had lower HbA1c and daily insulin requirement.

Geniposide inhibits glucolipotoxicity and cooperates with Txnip knockdown to potentiate cell adaption to endoplasmic reticulum stress in pancreatic beta cells

Thioredoxin-interacting protein (Txnip), a negative regulator of thioredoxin, has become an attractive therapeutic target to alleviate metabolic diseases. Our previous data demonstrated that geniposide improved glucose-stimulated insulin secretion by accelerating Txnip degradation and prevented the early-stage apoptosis of pancreatic β cells induced by palmitate, but the underlying mechanisms are still unclear. The objective of this study is to identify the role of Txnip in geniposide preventing the apoptosis of pancreatic β cells induced by high glucose and palmitate (HG/PA). The results revealed that geniposide attenuated HG/PA-induced cell apoptosis and the expression of Bax and caspase-3, while increasing mitochondrial membrane potential and the anti-apoptotic protein levels of heme-oxygenase-1 (HO-1) and Bcl-2 in INS-1 rat pancreatic β cells. Knockdown of the Txnip gene raised the levels of anti-apoptotic proteins HO-1 and Bcl-2 and geniposide potentiated the effect of Txnip when the INS-1 cells were challenged by HG/PA. Furthermore, geniposide enhanced the adoptive unfolded protein response by increasing the phosphorylation of PERK/eIF2α and IRE1α in HG/PA-treated INS-1 cells. The results together suggest that geniposide might be useful to antagonize glucolipotoxicity and Txnip might be a pleiotropic cellular factor in pancreatic β cells.

The remission phase in type 1 diabetes: Changing epidemiology, definitions, and emerging immuno-metabolic mechanisms

Type 1 diabetes mellitus (T1DM) is characterized by irreversible islet β cell destruction. During the progression of this disease, some patients with T1DM experience a phase of remission known as honeymoon or partial remission (PR) that is mainly characterized by satisfactory glycemic control and the transient recovery of islet β cell function. This special phase is a good model for studying the mechanism of β cell protection, might serve as a proper intervention period for immunotherapy, and may be related to disease prognosis. This special stage is highly valuable for studies aiming to identify possible targets that may be used to cure T1DM. An in-depth understanding of the diagnosis, epidemiology, and possible mechanisms of the PR phase is highly needed. In general, patients enter the PR phase approximately 3 months after starting insulin therapy, and this phase could be sustained for 6 to 9 months. Current research increasingly focuses on the metabolic and immunological aspects to constantly update our understanding of this phase. This review concentrates on the PR phase of T1DM to provide a comprehensive outlook of its epidemiology, diagnostic criteria, and underlying immune metabolic mechanisms.

Interleukin-6 and Interleukin-15 as Possible Biomarkers of the Risk of Autoimmune Diabetes Development

Aim

The aim of our study was to assay circulating interleukin-15 (IL-15) and interleukin-6 (IL-6) levels and insulin resistance measured by two different methods in newly diagnosed autoimmune diabetes (AD) patients, their I° relatives, and healthy controls.

Material and Methods

The group studied consisted of 54 patients with AD (28 with Latent Autoimmune Diabetes in Adults (LADA) and 26 with type 1 diabetes (T1D)), 70 first-degree relatives, and 60 controls. IL-6, IL-15, and anti-islet antibodies concentrations were measured by ELISA method. Homeostatic model assessment-insulin resistance (HOMAIR) and estimated glucose disposal rate (eGDR) were calculated.

Results

The patients with AD had significantly higher IL-15, IL-6, and HOMAIR and lower eGDR than the controls (p < 0.001, respectively) and first-degree relatives (p < 0.001, respectively). Significantly higher IL-15 and IL-6 were shown in the relatives with positive Ab as compared to the relatives without antibodies (p < 0.001, respectively) and the controls (p < 0.001, respectively). IL-15 negatively correlated with eGDR (r = −0.436, p = 0.021) in LADA and positively with HOMAIR in LADA and T1D (r = 0.507, p < 0.001; r = 0.4209, p < 0.001).

Conclusions

Significantly higher IL-15 and IL-6 concentrations, HOMAIR, and markedly lower eGDR in newly diagnosed AD patients and first-degree relatives with positive anti-islet antibodies might suggest the role of these pro-inflammatory cytokines and insulin resistance in the pathogenesis of autoimmune diabetes. IL-15 and IL-6 might be used as biomarkers of the risk of autoimmune diabetes development, in particular IL-15 for LADA. Both methods of IR measurement appear equally useful for calculating insulin resistance in autoimmune diabetes.

Remission phase in children diagnosed with type 1 diabetes in years 2012 to 2013 in Silesia, Poland: An observational study

BACKGROUND/OBJECTIVE

The study aimed to analyze the frequency of partial remission (PR) and its association with chosen clinical and laboratory factors among pediatric patients with newly diagnosed type 1 diabetes (T1D). The long-term effect of PR on chosen parameters was also investigated.

METHODS

In 194 patients (95 girls) aged 8.1 ± 4.3 years, we analyzed data at T1D onset: glycemia, pH, C-peptide, antibodies, weight, and concomitant autoimmune diseases. Anthropometric parameters, daily insulin requirement (DIR), and HbA1c 2 and 4 years after T1D diagnosis were also analyzed. We determined PR based on HbA1c and DIR measurements at least every 3 months.

RESULTS

PR occurred in 59% of patients. Remitters had significantly higher pH (7.33 vs 7.28, P = 0.03), weight SD score (SDS) (0.25 vs -0.24, P = 0.002), and body mass index SDS (0.19 vs -0.66, P = 0.02) compared with non-remitters. Concomitant diseases correlated negatively with PR. Multivariate analysis indicated only pH at onset was an independent predictor of PR. pH was the most important factor associated with the beginning of PR. There was a positive correlation between the start and duration of PR. Four years after T1D onset remitters had lower HbA1c (7.24% vs 8.05%, 53 vs 63.9 mmol/mol, P < 0.001) and DIR (0.81 vs 1.08, P = 0.005).

CONCLUSIONS

PR occurred quite often and developed more frequently in children with higher: weight and BMI SDS, but the main factor influencing PR presence and duration was higher pH at T1D onset. There was a beneficial impact of PR on HbA1c and DIR after 4 years of treatment.

Immune cell and cytokine patterns in children with type 1 diabetes mellitus undergoing a remission phase: A longitudinal study

OBJECTIVE

Type 1 diabetes (T1D) develops in distinct stages, before and after disease onset. Whether the natural course translates into different immunologic patterns is still uncertain. This study aimed at identifying peripheral immune patterns at key time-points, in T1D children undergoing remission phase.

METHODS

Children with new-onset T1D and healthy age and gender-matched controls were recruited at a pediatric hospital. Peripheral blood samples were evaluated by flow cytometry at 3 longitudinal time-points: onset (T1), remission phase (T2) and established disease (T3). Cytokine levels were quantified by multiplex assay. Fasting C-peptide, HbA1c, and 25OHD were also measured.

RESULTS

T1D children (n = 28; 10.0 ± 2.6 years) showed significant differences from controls in circulating neutrophils, T helper (Th)17 and natural killer (NK) cells, with relevant variations during disease progression. At onset, neutrophils, NK, Th17 and T cytotoxic (Tc)17 cells were decreased. As disease progressed, neutrophil counts recovered whereas NK counts remained low. Th17 and Tc17 cells behavior followed the neutrophil variation pattern. B-cells were lowest in the remission phase and regulatory T-cells significantly declined after remission. Two cytokine response profiles were identified. Low cytokine-responders showed higher circulating fasting C-peptide levels at onset and longer remission periods. C-peptide inversely correlated with pro-inflammatory and cytotoxic cells.

CONCLUSIONS

Our data suggest an association between immune cells, cytokine patterns and metabolic counterparts. The dynamic changes of circulating immune cells during disease progression involve key innate and acquired immune cell types. This longitudinal picture of T1D progression may enable disease staging and patient stratification, essential for individualized treatment.

Potential beneficial effects of a gluten-free diet in newly diagnosed children with type 1 diabetes: a pilot study

AIM

Gluten-free diet has shown promising effects in preventing type 1 diabetes (T1D) in animals as well as beneficial effects on the immune system. Gluten-free diet at diabetes onset may alter the natural course and outcome of autoimmune diseases such as T1D.

METHODS

In a 12-month study, 15 children newly diagnosed with T1D were instructed to follow a gluten-free diet. Questionnaires were used to evaluate adherence to the gluten-free diet. Partial remission (PR) was defined by insulin dose-adjusted A1c (IDAA1c) ≤9 or stimulated C-peptide (SCP) >300 pmol/L measured 90 min after a liquid mixed meal at the inclusion, six and 12 months after onset. The intervention group was compared with two previous cohorts. Linear mixed models were used to estimate differences between cohorts.

RESULTS

After 6 months, more children on a gluten-free diet tended to have SCP values above 300 pmol/L compared to the European cohort (p = 0.08). The adherence to a gluten-free diet decreased during the 12-month study period. After 1 year there was no difference in SCP levels or percentage in remission according to SCP (p > 0.1). Three times as many children were still in PR based on IDAA1c (p < 0.05). Twelve months after onset HbA1c were 21 % lower and IDAA1c >1 unit lower in the cohort on a gluten-free diet compared to the two previous cohorts (p < 0.001).

CONCLUSION

Gluten-free diet is feasible in highly motivated families and is associated with a significantly better outcome as assessed by HbA1c and IDAA1c. This finding needs confirmation in a randomized trial including screening for quality of life. (Clinicaltrials.gov number NCT02284815).

Influence of remission and its duration on development of early microvascular complications in young adults with type 1 diabetes

INTRODUCTION

Prevalence of partial remission ranges between 20% and 80% in the initial course of type 1 diabetes. In this phase of the disease, a substantial insulin secretion contributes to good metabolic control. The aim of the study was to determine the association between presence of partial remission and occurrence of microangiopathy complications in type 1 diabetes.

MATERIAL AND METHODS

Ninety-eight consecutive patients with newly diagnosed type 1 diabetes were asked to participate in a cohort study. Partial remission was defined as the time in which all of the following criteria were met: HbA1c below 6.5% (48mmol/mol), daily insulin requirement below 0.3 U/kg body weight and serum Cpeptide concentration above 0.5ng/ml. Patients were divided into those who were in remission at any time during follow-up (remitters) and non-remitters. After 7years of follow-up, the occurrence of microangiopathy complications was analyzed. In statistical analysis, Mann-Whitney test, chi(2) test and Fisher test were used for analysis between groups. We applied a Cox's multivariate regression model and univariate regression method. P<0.05 was considered statistically significant.

RESULTS

In univariate logistic regression, a significant association was found between absence of remission and occurrence of at least one microvascular complication. In the Cox proportional hazards regression model that included clinically significant parameters at diagnosis (presence of ketoacidosis, cigarette smoking and HbA1c value) as covariates, absence of remission was associated with occurrence of chronic complications of diabetes at 7years [HR: 3.65 (95% CI 1.23-4.56), p=0.04]. In non-remitters, higher incidence of at least one microvascular complication (46.4% vs. 7.6%), higher incidence of retinopathy (42.8% vs. 5.7%), and neuropathy (21.4% vs. 1.9%) was found.

CONCLUSIONS

Occurrence of partial remission of diabetes is associated with a reduced risk of chronic microvascular complications at 7-year follow-up.

TNF-α Antibody Therapy in Combination With the T-Cell-Specific Antibody Anti-TCR Reverses the Diabetic Metabolic State in the LEW.1AR1-iddm Rat

Anti-tumor necrosis factor-α (TNF-α) therapy (5 mg/kg body weight), alone or combined with the T-cell-specific antibody anti-T-cell receptor (TCR) (0.5 mg/kg body weight), was performed over 5 days immediately after disease manifestation to reverse the diabetic metabolic state in the LEW.1AR1-iddm rat, an animal model of human type 1 diabetes. Only combination therapy starting at blood glucose concentrations below 15 mmol/L restored normoglycemia and normalized C-peptide. Increased β-cell proliferation and reduced apoptosis led to a restoration of β-cell mass along with an immune cell infiltration-free pancreas 60 days after the end of therapy. This combination of two antibodies, anti-TCR/CD3, as a cornerstone compound in anti-T-cell therapy, and anti-TNF-α, as the most prominent and effective therapeutic antibody in suppressing TNF-α action in many autoimmune diseases, was able to reverse the diabetic metabolic state. With increasing blood glucose concentrations during the disease progression, however, the proapoptotic pressure on the residual β-cell mass increased, ultimately reaching a point where the reservoir of the surviving β-cells was insufficient to allow a restoration of normal β-cell mass through regeneration. The present results may open a therapeutic window for reversal of diabetic hyperglycemia in patients, worthwhile of being tested in clinical trials.

Anti-TCR therapy combined with fingolimod for reversal of diabetic hyperglycemia by β cell regeneration in the LEW.1AR1-iddm rat model of type 1 diabetes

The therapeutic capacity of an antibody directed against the T cell receptor (anti-TCR) of the TCR/CD3 complex alone or in combination with fingolimod (FTY720) to reverse the diabetic metabolic state through suppression of autoimmunity and stimulation of β cell regeneration was analyzed in the LEW.1AR1-iddm (IDDM) rat, an animal model of human type 1 diabetes. Animals were treated with anti-TCR (0.5 mg/kg body weight for 5 days) monotherapy or in combination with fingolimod (1 mg/kg body weight for 40 days). Metabolic changes and β cell morphology were analyzed before, immediately after, and 60 days after end of therapy. Both therapies were started early after disease manifestation and led to normoglycemia in parallel with an increase of the C-peptide concentration. Combination therapy increased the β cell mass reaching a range of normoglycemic controls, decreased the apoptosis rate fivefold, and increased the proliferation rate threefold. Additionally, at 60 days after therapy, islets were virtually free of T cells, macrophages, and cytokine expression. In contrast, after anti-TCR monotherapy, β cell mass remained low with an activated immune cell infiltrate. A concomitant fivefold increased β cell apoptosis rate resulted in a complete loss of β cells. Only combination therapy yielded sustained normoglycemia with full reversal of islet infiltration and restoration of pancreatic β cell mass.

KEY MESSAGE

Combination therapy of anti-TCR and fingolimod was effective in the reversal of T1D. Combination therapy increased the pancreatic β cell mass to normoglycemic control levels. Combination therapy leads to a full reversal of pancreatic islet infiltration. Anti-TCR monotherapy did not abolish islet infiltration. Combination therapy was successful only immediately after diabetes manifestation.

Increased resistin serum concentrations in patientswith type 1 diabetes mellitus

OBJECTIVE

Adiponectin, leptin, and resistin are adipokines which play a significant role in the regulation of lipid and carbohydrate metabolism in patients with type 2 diabetes, while little is known about their role in type 1 diabetes mellitus (T1DM). The aim of this study was to measure serum adiponectin, leptin, and resistin levels and to investigate their relationships with some parameters in patients with T1DM and healthy controls.

METHODS

Fifty children and adolescents with T1DM (21 boys and 29 girls) and 33 healthy control subjects (18 boys and 15 girls) participated in the study. All subjects were patients followed in the Pediatric Endocrinology and Metabolism Unit of Gaziantep University Faculty of Medicine. None of the subjects had hypertension, obesity, hyperlipidemia, anemia, or infection. Adiponectin, leptin, and resistin levels were analyzed with ELISA.

RESULTS

There were no statistically significant differences related with age, sex, pubertal status, or body mass index distribution between the diabetic and control groups. Resistin levels were significantly higher in the diabetic group compared to controls (5.26±3.15 ng/mL vs. 3.50±1.26 ng/mL; p<0.01).

CONCLUSION

Of the three investigated adipokines, only resistin was associated with T1DM. Resistin may play a role in the process of inflammation and also in the pathophysiology of T1DM.

Meta-immunological profiling of children with type 1 diabetes identifies new biomarkers to monitor disease progression

Type 1 diabetes is characterized by autoimmune destruction of pancreatic β-cells in genetically susceptible individuals. Triggers of islet autoimmunity, time course, and the precise mechanisms responsible for the progressive β-cell failure are not completely understood. The recent escalation of obesity in affluent countries has been suggested to contribute to the increased incidence of type 1 diabetes. Understanding the link between metabolism and immune tolerance could lead to the identification of new markers for the monitoring of disease onset and progression. We studied several immune cell subsets and factors with high metabolic impact as markers associated with disease progression in high-risk subjects and type 1 diabetic patients at onset and at 12 and 24 months after diagnosis. A multiple correlation matrix among different parameters was evaluated statistically and assessed visually on two-dimensional graphs. Markers to predict residual β-cell function up to 1 year after diagnosis were identified in multivariate logistic regression models. The meta-immunological profile changed significantly over time in patients, and a specific signature that was associated with worsening disease was identified. A multivariate logistic regression model measuring age, BMI, fasting C-peptide, number of circulating CD3(+)CD16(+)CD56(+) cells, and the percentage of CD1c(+)CD19(-)CD14(-)CD303(-) type 1 myeloid dendritic cells at disease onset had a significant predictive value. The identification of a specific meta-immunological profile associated with disease status may contribute to our understanding of the basis of diabetes progression.

Association between age, IL-10, IFNγ, stimulated C-peptide and disease progression in children with newly diagnosed Type 1 diabetes

AIMS

The relation of disease progression and age, serum interleukin 10 (IL-10) and interferon gamma (IFNγ) and their genetic correlates were studied in paediatric patients with newly diagnosed Type 1 diabetes.

METHODS

Two hundred and twenty-seven patients from the Hvidoere Study Group were classified in four different progression groups as assessed by change in stimulated C-peptide from 1 to 6 months. CA repeat variants of the IL-10 and IFNγ gene were genotyped and serum levels of IL-10 and IFNγ were measured at 1, 6 and 12 months.

RESULTS

IL-10 decreased (P < 0.001) by 7.7% (1 month), 10.4% (6 months) and 8.6% (12 months) per year increase in age of child, while a twofold higher C-peptide concentration at 1 month (p = 0.06), 6 months (P = 0.0003) and 12 months (P = 0.02) was associated with 9.7%, 18.6% and 9.7% lower IL-10 levels, independent of each other. IL-10 concentrations did not associate with the disease progression groups. By contrast, IFNγ concentrations differed between the four progression groups at 6 and 12 months (P = 0.02 and P = 0.01, respectively); patients with rapid progressing disease had the highest levels at both time points. Distribution of IL-10 and IFNγ genotypes was equal among patients from the progression groups.

CONCLUSION

IL-10 serum levels associate inversely with age and C-peptide. As age and C-peptide also associate, a triangular association is proposed. Genetic influence on IL-10 production seems to be masked by distinct disease mechanisms. Increased serum IFNγ concentrations associate with rapid disease progression. Functional genetic variants do not associate with a single progression pattern group, implying that disease processes override genetically predisposed cytokine production.

Serum titres of anti-glutamic acid decarboxylase-65 and anti-IA-2 autoantibodies are associated with different immunoregulatory milieu in newly diagnosed type 1 diabetes patients

Several studies correlated genetic background and pancreatic islet-cell autoantibody status (type and number) in type 1A diabetes mellitus (T1AD), but there are no data evaluating the relationship among these markers with serum cytokines, regulatory T cells and β cell function. This characterization has a potential importance with regard to T1AD patients' stratification and follow-up in therapeutic prevention. In this study we showed that peripheral sera cytokines [interleukin (IL)-12, IL-6, II-1β, tumour necrosis factor (TNF)-α, IL-10] and chemokines (CXCL10, CXCL8, CXCL9, CCL2) measured were significantly higher in newly diagnosed T1AD patients when compared to healthy controls (P < 0·001). Among T1AD, we found a positive correlation between CXCL10 and CCL-2 (r = 0·80; P = 0·000), IL-8 and TNF-α (r = 0·60; P = 0·000); IL-8 and IL-12 (r = 0·57; P = 0·001) and TNF-α and IL-12 (r = 0·93; P = 0·000). Glutamic acid decarboxylase-65 (GAD-65) autoantibodies (GADA) were associated negatively with CXCL10 (r = -0·45; P = 0·011) and CCL2 (r = -0·65; P = 0·000), while IA-2A showed a negative correlation with IL-10 (r = -0·38; P = 0·027). Human leucocyte antigen (HLA) DR3, DR4 or DR3/DR4 and PTPN22 polymorphism did not show any association with pancreatic islet cell antibodies or cytokines studied. In summary, our results revealed that T1AD have a proinflammatory cytokine profile compared to healthy controls and that IA-2A sera titres seem to be associated with a more inflammatory peripheral cytokine/chemokine profile than GADA. A confirmation of these data in the pre-T1AD phase could help to explain the mechanistic of the well-known role of IA-2A as a more specific marker of beta-cell damage than GADA during the natural history of T1AD.

Smoking and other factors associated with short-term partial remission of Type 1 diabetes in adults

AIMS

The duration of partial remission of Type 1 diabetes is associated with the degree of initial metabolic disturbance and features of insulin resistance. Cigarette smoking decreases insulin sensitivity, but its influence on the length of remission is unknown. Therefore, this study assessed the relationship between cigarette smoking and duration of partial remission in adults with newly diagnosed Type 1 diabetes.

METHODS

We recruited 149 patients (48 women and 101 men, aged 16-35 years, median age 25 years), admitted to a teaching hospital with newly diagnosed Type 1 diabetes and followed them for a median period of 1 year and 9 months. We introduced intensive insulin therapy in multiple injections (basal-bolus) in all patients. We defined partial remission as an insulin dose of ≤ 0.3 U/kg body weight/24 h, an HbA(1c) value < 53 mmol/mol (7.0%) and a random serum C-peptide concentration over 0.5 ng/ml. Cigarette smoking was determined by self-report.

RESULTS

Of 149 patients, 68 (46%) fulfilled the criteria for partial remission at 1 year after diagnosis of diabetes. Fewer patients who were in partial remission at 1 year smoked (19/68, 28%) than did patients that were not in partial remission (41/81, 51%). In logistic regression analyses, non-smoking was associated with remission at 1 year independent of age, sex, HbA(1c) and presence of diabetic ketoacidosis, all measured at onset of diabetes (OR 3.32, 95% CI 1.42-7.75, P = 0.005).

CONCLUSION

Relative to individuals in this study who smoked, those who did not smoke at diagnosis of Type 1 diabetes experienced a longer duration of partial remission.

Association of adiponectin, interleukin (IL)-1ra, inducible protein 10, IL-6 and number of islet autoantibodies with progression patterns of type 1 diabetes the first year after diagnosis

The progression of type 1 diabetes after diagnosis is poorly understood. Our aim was to assess the relation of disease progression of juvenile-onset type 1 diabetes, determined by preserved beta cell function the first year after diagnosis, with systemic cytokine concentrations and number of autoantibodies. Juvenile patients (n = 227) had a meal-stimulated C-peptide test 1 and 6 months after diagnosis. On the basis of the C-peptide course for the duration of 1-6 months, four progression groups were defined: patients with persistently low beta cell function ('stable-low'), rapid progressers, slow progressers and remitters. Serum concentrations of adiponectin, interleukin (IL)-1ra, inducible protein 10 (IP-10), IL-6 and glutamic acid decarboxylase (GAD), IA-2A and islet-cell antibodies (ICA) were measured at 1, 6 and 12 months. We found that adiponectin concentrations at 1 month predicted disease progression at 6 months (P = 0·04). Patients with low adiponectin had a higher probability of becoming remitters than rapid progressers, odds ratio 3·1 (1·3-7·6). At 6 and 12 months, adiponectin differed significantly between the groups, with highest concentrations among stable-low and rapid progressers patients (P = 0·03 and P = 0·006). IL-1ra, IP-10 and IL-6 did not differ between the groups at any time-point. The number of autoantibodies differed significantly between the groups at 1 month (P = 0·04), where rapid progressers had the largest number. There was no difference between the groups in human leucocyte antigen-associated risk. We define progression patterns distinguishing patients diagnosed with low beta cell function from those with rapid decline, slow decline or actual increase in beta cell function, pointing to different mechanisms of disease progression. We find that adiponectin concentration at 1 month predicts, and at 6 and 12 months associates with, distinct progression patterns.

Multinational study in children and adolescents with newly diagnosed type 1 diabetes: association of age, ketoacidosis, HLA status, and autoantibodies on residual beta-cell function and glycemic control 12 months after diagnosis

OBJECTIVE

To identify predictors of residual beta-cell function and glycemic control during the first 12 months after the diagnosis of type 1 diabetes (T1D).

SUBJECTS AND METHODS

Clinical information and blood samples were collected from 275 children. HbA1c, antibodies, HLA typing and mixed meal-stimulated C-peptide levels 1, 6, and 12 months after diagnosis were analyzed centrally.

RESULTS

Mean age at diagnosis was 9.1 yr. DKA with standard bicarbonate <15 mmol/L was associated with significantly poorer residual beta-cell function 1 (p = 0.004) and 12 months (p = 0.0003) after diagnosis. At 12 months, the decline in stimulated C-peptide levels compared with the levels at 1 month was 69% in the youngest age group and 50% in patients 10 yr and above (p < 0.001). Stimulated C-peptide at 12 months was predicted by younger age (p < 0.02) and bicarbonate levels at diagnosis (p = 0.005), and by stimulated C-peptide (p < 0.0001), postmeal blood glucose (p = 0.0004), insulin antibodies (IA; p = 0.02) and glutamic acid decarboxylase antibodies (GADA; p = 0.0004) at 1 month. HbA1c at 12 months was predicted by HbA1c at diagnosis (p < 0.0001), GADA at 1 month (p = 0.01), and non-white Caucasian ethnicity (p = 0.002).

CONCLUSIONS

Younger age, ketoacidosis at diagnosis, and IA and GADA 1 month after diagnosis were the strongest explanatory factors for residual beta-cell function at 12 months. Glycemic control at 12 months was influenced predominantly by ethnicity, HbA1c at diagnosis, and GADA at 1 month.

Blockade of interleukin 1 in type 1 diabetes mellitus

Interleukin 1 (IL-1) is a 17 kDa protein highly conserved through evolution and is a key mediator of inflammation, fever and the acute-phase response. IL-1 has important functions in the innate immune defense against microbes, trauma and stress, and is also an effector molecule involved in tissue destruction and fibrosis. The inhibition of IL-1 action has clinical efficacy in many inflammatory diseases, such as hereditary autoinflammatory disorders, familial hereditary fever, gout, rheumatoid arthritis and type 2 diabetes mellitus (T2DM). The latter is a common metabolic condition caused by insulin resistance and pancreatic beta-cell failure, the causes of both of which have inflammatory components. IL-1 signaling has roles in beta-cell dysfunction and destruction via the NFkappaB and mitogen-activated-protein-kinase pathways, leading to endoplasmic reticulum and mitochondrial stress and eventually activating the apoptotic machinery. In addition, IL-1 acts on T-lymphocyte regulation. The modulating effect of IL-1 on the interaction between the innate and adaptive immune systems and the effects of IL-1 on the beta-cell point to this molecule being a potential interventional target in autoimmune diabetes mellitus. Genetic or pharmacological abrogation of IL-1 action reduces disease incidence in animal models of type 1 diabetes mellitus (T1DM) and clinical trials have been started to study the feasibility, safety and efficacy of IL-1 therapy in patients with T1DM. Here, we review the rationale for blocking IL-1 in patients with T1DM.

The honeymoon phase: intersection of metabolism and immunology

PURPOSE OF REVIEW

Even though the honeymoon phase in type 1 diabetes mellitus has been well known, its underlying pathogenic mechanisms remain poorly described. The common explanation that it occurs due to 'beta-cell rest' on initiation of insulin therapy seems inadequate based on recent observations and studies and its underlying immunological aspects overlooked.

RECENT FINDINGS

In this article, we will review the metabolic and immunological aspects of the honeymoon phase and we will present our current model of the pathophysiology of this phase. Our view is that it is one of many phases of remission occurring basically due to development of adaptive immune tolerance along the course of type 1 diabetes. We will also review new findings of the interplay between metabolic factors (ambient glucose level) and immune function.

SUMMARY

The honeymoon phase provides a unique model to understand the pathogenesis of type 1 diabetes. Research to unravel its immune pathogenesis is needed. It may turn out that the optimum form of intervention in type 1 diabetes is one that combines enhancement of antigen-specific adaptive immune tolerance with optimized metabolic control in order to keep cytotoxic T cells anergic.

Relation of circulating concentrations of chemokine receptor CCR5 ligands to C-peptide, proinsulin and HbA1c and disease progression in type 1 diabetes

Th1 related chemokines CCL3 and CCL5 and Th2 related CCL4 as ligands of the receptor CCR5 contribute to disease development in animal models of type 1 diabetes. In humans, no data are available addressing the role of these chemokines regarding disease progression and remission. We investigated longitudinally circulating concentrations of CCR5 ligands of 256 newly diagnosed patients with type 1 diabetes. CCR5 ligands were differentially associated with beta-cell function and clinical remission. CCL5 was decreased in remitters and positively associated with HbA1c suggestive of a Th1 associated progression of the disease. Likewise, CCL3 was negatively related to C-peptide and positively associated with the beta-cell stress marker proinsulin but increased in remitters. CCL4 associated with decreased beta-cell stress shown by negative association with proinsulin. Blockage of chemokines or antagonism of CCR5 by therapeutic agents such as maraviroc may provide a new therapeutic target to ameliorate disease progression in type 1 diabetes.

Association of IL-1ra and adiponectin with C-peptide and remission in patients with type 1 diabetes

OBJECTIVE

We investigated the association of anti-inflammatory cytokine interleukin (IL)-1 receptor antagonist (IL-1ra), adiponectin, proinflammatory cytokines IL-1 beta, IL-6, and CCL2, and tumor necrosis factor-alpha with beta-cell function, metabolic status, and clinical remission in patients with recent-onset type 1 diabetes.

RESEARCH DESIGN AND METHODS

Serum was obtained from 256 newly diagnosed patients (122 males and 134 females, median age 9.6 years). Stimulated C-peptide, blood glucose, and A1C were determined in addition to circulating concentration of cytokines at 1, 6, and 12 months after diagnosis. Analyses were adjusted for sex, age, and BMI percentile.

RESULTS

Anti-inflammatory IL-1ra was positively associated with C-peptide after 6 (P = 0.0009) and 12 (P = 0.009) months. The beneficial association of IL-1ra on beta-cell function was complemented by the negative association of IL-1 beta with C-peptide after 1 month (P = 0.009). In contrast, anti-inflammatory adiponectin was elevated in patients with poor metabolic control after 6 and 12 months (P < 0.05) and positively correlated with A1C after 1 month (P = 0.0004). Proinflammatory IL-6 was elevated in patients with good metabolic control after 1 month (P = 0.009) and showed a positive association with blood glucose disposal after 12 months (P = 0.047).

CONCLUSIONS

IL-1ra is associated with preserved beta-cell capacity in type 1 diabetes. This novel finding indicates that administration of IL-1ra, successfully improving beta-cell function in type 2 diabetes, may also be a new therapeutic approach in type 1 diabetes. The relation of adiponectin and IL-6 with remission and metabolic status transfers observations from in vitro and animal models into the human situation in vivo.

Glucose and leptin induce apoptosis in human beta-cells and impair glucose-stimulated insulin secretion through activation of c-Jun N-terminal kinases

c-Jun N-terminal kinases (SAPK/JNKs) are activated by inflammatory cytokines, and JNK signaling is involved in insulin resistance and beta-cell secretory function and survival. Chronic high glucose concentrations and leptin induce interleukin-1beta (IL-1beta) secretion from pancreatic islets, an event that is possibly causal in promoting beta-cell dysfunction and death. The present study provides evidence that chronically elevated concentrations of leptin and glucose induce beta-cell apoptosis through activation of the JNK pathway in human islets and in insulinoma (INS 832/13) cells. JNK inhibition by the dominant inhibitor JNK-binding domain of IB1/JIP-1 (JNKi) reduced JNK activity and apoptosis induced by leptin and glucose. Exposure of human islets to leptin and high glucose concentrations leads to a decrease of glucose-induced insulin secretion, which was partly restored by JNKi. We detected an interplay between the JNK cascade and the caspase 1/IL-1beta-converting enzyme in human islets. The caspase 1 gene, which contains a potential activating protein-1 binding site, was up-regulated in pancreatic sections and in isolated islets from type 2 diabetic patients. Similarly, cultured human islets exposed to high glucose- and leptin-induced caspase 1 and JNK inhibition prevented this up-regulation. Therefore, JNK inhibition may protect beta-cells from the deleterious effects of high glucose and leptin in diabetes.