Development Of T1D Research Articles

Food Consumption and the Risk of Type 1 Diabetes in Children and Youth: A Population-Based, Case-Control Study in Prince Edward Island, Canada

Objective: The objective of this study was to determine if the consumption of certain foods during the year prior to diagnosis of type 1 diabetes mellitus (T1D) was associated with the risk of developing T1D in children and youth residing in Prince Edward Island, Canada.Methods: Cases (n = 57) consisted of newly diagnosed patients with T1D during 2001 to 2004. Controls (n = 105) were randomly selected from the province's population, and matched to cases by age at diagnosis and sex. Food consumption in cases and controls was assessed using two previously validated food frequency questionnaires, and a survey was developed to collect information on potential environmental and genetic risk factors.Results: The median age at diagnosis was nine years, and 67% of cases were male. After controlling for the matched variables and four significant environmental and genetic risk factors (family members with T1D, the number of infections during the first two years of life, place of residence, and father's education) in the final logistic regression model, the consumption of regular soft drinks (OR = 2.78, 95% CI = 1.21, 6.36) and eggs (OR = 2.50, 95% CI = 1.09, 5.75) were significant risk factors of T1D, when consumed once per week or more often.Conclusion: Diet may play a role in the development of T1D. However, further research is needed to confirm these observed associations.

Evaluation of the association between the common E469K polymorphism in the ICAM-1 gene and diabetic nephropathy among type 1 diabetic patients in GoKinD population

BackgroundThe ICAM-1 gene is a strong positional and biological candidate for susceptibility to the development of T1D and DN. We have recently demonstrated that SNP rs5498(E469K) confers susceptibility to the development of T1D and might be associated with DN in Swedish Caucasians. The present study aimed to further evaluate the association between the ICAM-1 genetic polymorphisms and DN.MethodsTwo common non-synonymous SNPs, including rs5498(E469K) and rs1799969(R241G), in the ICAM-1 gene were genotyped in 662 (312 female/350 male) T1D patients with DN and 620 (369/251) without DN. All patients were selected from the GoKinD study.ResultsGenotype distributions of both SNPs were in Hardy-Weinberg equilibrium but SNP rs5498(E469K) had high heterozygous index. In this SNP, the heterozygosity and positivity for the allele G were found to be significantly associated with DN in female T1D patients (P = 0.010, OR = 0.633, CI 95% 0.447–0.895 and P = 0.026, OR = 0.692, CI 95% 0.500–0.958). Furthermore, the female patients without DN carrying three genotypes A/A, A/G and G/G had different cystatin levels (0.79 ± 0.17, 0.81 ± 0.14 and 0.75 ± 0.12 mg/L, P = 0.021). No significant association of SNP rs1799969 (R241G) with DN was found.ConclusionThe present study provides further evidence that SNP rs5498(E469K) in the ICAM-1 gene presents a high heterozygous index and the allele G of this polymorphism may confers the decreased risk susceptibility to the development of DN in female T1D patients among the GoKinD population.

Psychological stress as a factor potentially contributing to the pathogenesis of Type 1 diabetes mellitus

Diabetes mellitus Type 1 (T1D) is an autoimmune disorder attributed to both genetic and environmental factors. The aim of this study was to identify certain stressful conditions potentially associated with the pathogenesis and/or expression of T1D. The study group included 107 children with diabetes (CD) and 153 controls of comparable age and gender distribution at diagnosis of T1D (10.73+/-3.62 yr vs 9.59 +/-3.42 yr, respectively). The parents of both groups completed a questionnaire on socioeconomic status and stressful life events or adverse situations at home and school. Lower social class was more prevalent among the mothers of CD (p=0.002) in comparison with the controls. Stressful life events (parental death, divorce, parental job loss), problems at home (parental abuse, parental dispute) and at school (poor performance) were more frequently observed in the CD group than in the controls (parental death: p=0.05, job loss: p=0.05, parental abuse: p=0.002, quarrels between parents: p=0.05, and among siblings p=0.002, poor school performance: p=0.037). A stepwise logistic regression analysis indicated that lower maternal social class [odds ratio (OR): 3.86, 95% confidence interval (CI): 1.37,10.9], parental dispute or divorce (OR: 2.78, 95%CI: 0.97,7.95), body mass index (OR: 0.87, 95%CI: 0.78,0.97), increasing age (OR: 1.14, 95%CI: 1.02,1.27) were the factors potentially influencing the occurrence of T1D, while the 2-yr period prior to diabetes occurrence emerged as the most important one (OR: 2.49, 95%CI: 1.14,5.42). Children with diabetes seem to experience certain stressful conditions with significantly increased frequency compared to controls, especially during the 2 yr preceding the diagnosis of T1D, with a higher clustering in those of lower social class. The resultant stress possibly contributes to the development of T1D in genetically susceptible individuals.

Role of Regulatory T Cells for the Treatment of Type 1 Diabetes Mellitus

Beta-cell specific autoreactive T cells can be found in patients with type I diabetes (T1D) and in healthy controls. They are usually controlled by a network of regulatory mechanisms including CD4+CD25+Foxp3+ regulatory T cells (Tregs). It was suspected that defects in Treg number and activity are causally related to the development of T1D. Although there are hints that this concept might be true, it is neither proven in animal models nor in patients with T1D. However, increasing the number of Tregs by adoptive transfer can be used to prevent and treat even established T1D. It was demonstrated that Tregs recognizing beta-cell antigens are far more efficient in treating the disease than polyspecific Tregs. The use of beta-cell specific Tregs is also leading to a tissue specific immunotolerance without perturbing the general immunocompetence. Two sources for beta-cell specific Tregs are currently employed: First natural Tregs specific for beta-cells are expanded IN VITRO and reinfused into diabetic animals. Second naïve or activated T cells specific for beta-cell antigens are IN VITRO converted to Tregs by genetic manipulation or by specific cytokine combinations. Both approaches were successful in treating even established diabetes in animal models. Before such therapies can be used in patients safety measures regarding the fate and the effects of the transferred Tregs have to be studied. Besides this ethical considerations are important in regard to what risks we should take to treat a disease in young patients which can otherwise be treated medically. In the meantime the concept of Tregs for therapy of T1D is supported by successful clinical attempts to induce these cells IN VIVO by administration of monoclonal antibodies against CD3. If subsequent studies show that Tregs represent a safe and efficient source for therapy, they could become an important weapon in the fight against immune mediated pathology.

Activating Fcγ Receptors Participate in the Development of Autoimmune Diabetes in NOD Mice

Type 1 diabetes mellitus (T1D) in humans is an organ-specific autoimmune disease in which pancreatic islet beta cells are ruptured by autoreactive T cells. NOD mice, the most commonly used animal model of T1D, show early infiltration of leukocytes in the islets (insulitis), resulting in islet destruction and diabetes later. NOD mice produce various islet beta cell-specific autoantibodies, although it remains a subject of debate regarding whether these autoantibodies contribute to the development of T1D. Fc gammaRs are multipotent molecules that play important roles in Ab-mediated regulatory as well as effector functions in autoimmune diseases. To investigate the possible role of Fc gammaRs in NOD mice, we generated several Fc gammaR-less NOD lines, namely FcR common gamma-chain (Fc Rgamma)-deficient (NOD.gamma(-/-)), Fc gammaRIII-deficient (NOD.III(-/-)), Fc gammaRIIB-deficient (NOD.IIB(-/-)), and both Fc Rgamma and Fc gammaRIIB-deficient NOD (NOD.null) mice. In this study, we show significant protection from diabetes in NOD.gamma(-/-), NOD.III(-/-), and NOD.null, but not in NOD.IIB(-/-) mice even with grossly comparable production of autoantibodies among them. Insulitis in NOD.gamma(-/-) mice was also alleviated. Adoptive transfer of bone marrow-derived dendritic cells or NK cells from NOD mice rendered NOD.gamma(-/-) animals more susceptible to diabetes, suggesting a possible scenario in which activating Fc gammaRs on dendritic cells enhance autoantigen presentation leading to the activation of autoreactive T cells, and Fc gammaRIII on NK cells trigger Ab-dependent effector functions and inflammation. These findings highlight the critical roles of activating Fc gammaRs in the development of T1D, and indicate that Fc gammaRs are novel targets for therapies for T1D.

CT60 genotype does not affect CTLA-4 isoform expression despite association to T1D and AITD in northern Sweden.

BackgroundPolymorphisms in and around the CTLA-4 gene have previously been associated to T1D and AITD in several populations. One such single nucleotide polymorphism (SNP), CT60, has been reported to affect the expression level ratio of the soluble (sCTLA-4) to full length CTLA-4 (flCTLA-4) isoforms. The aims of our study were to replicate the association previously published by Ueda et al. of polymorphisms in the CTLA-4 region to T1D and AITD and to determine whether the CT60 polymorphism affects the expression level ratio of sCTLA-4/flCTLA-4 in our population.MethodsThree SNPs were genotyped in 253 cases (104 AITD cases and 149 T1D cases) and 865 ethnically matched controls. Blood from 23 healthy individuals was used to quantify mRNA expression of CTLA-4 isoforms in CD4+ cells using real-time PCR. Serum from 102 cases and 59 healthy individuals was used to determine the level of sCTLA-4 protein.ResultsHere we show association of the MH30, CT60 and JO31 polymorphisms to T1D and AITD in northern Sweden. We also observed a higher frequency of the CT60 disease susceptible allele in our controls compared to the British, Italian and Dutch populations, which might contribute to the high frequency of T1D in Sweden. In contrast to previously published findings, however, we were unable to find differences in the sCTLA-4/flCTLA-4 expression ratio based on the CT60 genotype in 23 healthy volunteers, also from northern Sweden. Analysis of sCTLA-4 protein levels in serum showed no correlation between sCTLA-4 protein levels and disease status or CT60 genotype.ConclusionAssociation was found between T1D/AITD and all three polymorphisms investigated. However, in contrast to previous investigations, sCTLA-4 RNA and protein expression levels did not differ based on CT60 genotype. Our results do not rule out the CT60 SNP as an important polymorphism in the development of T1D or AITD, but suggest that further investigations are necessary to elucidate the effect of the CTLA-4 region on the development of T1D and AITD.

Type 1 Diabetes and Multiple Sclerosis

Type 1 diabetes mellitus (T1D) and multiple sclerosis (MS) contribute considerably to the burden of autoimmune diseases in young adults. Although HLA patterns of T1D and MS are considered mutually exclusive, individual and familial co-occurrence of the 2 diseases has been reported. To assess the co-occurrence of T1D and MS by estimating the risk for MS in patients with T1D and the risk for T1D in first-degree relatives of patients with MS. Two population-based disease registers, the Danish Hospital Discharge Register and the Danish Multiple Sclerosis Register were used to identify patients with T1D, defined as patients in whom diabetes was diagnosed before age 20 years (N = 6078), and patients with MS (N = 11 862). First-degree relatives (N = 14,771) of patients with MS were identified from family information in the Danish Civil Registration System. Patients with T1D and first-degree relatives of patients with MS were followed up for occurrence of MS and T1D, respectively, and the relative risks were expressed as standardized incidence ratios, that is, ratios of observed to expected numbers of outcomes based on national age, sex, and period-specific MS and T1D incidence rates. Patients with T1D were at more than 3-fold increased risk for development of MS (relative risk, 3.26; 95% confidence interval, 1.80-5.88; n = 11). First-degree relatives of patients with MS were at 63% increased risk (relative risk, 1.63; 95% confidence interval, 1.26-2.12; n = 56) for development of T1D. However, adjusting for familial relationship to patients with T1D reduced the excess risk to 44% (relative risk, 1.44; 95% confidence interval, 1.11-1.88; n = 56). The present nationwide cohort study demonstrates an intraindividual and, to a lesser degree, an intrafamilial co-occurrence of MS and T1D.

Deficient activation and resistance to activation-induced apoptosis of cd8 + t cells is associated with defective peripheral tolerance in nonobese diabetic mice

Activation-induced cell death (AICD) is a mechanism of homeostasis that limits the clonal expansion of autoreactive T cells and regulates central and peripheral tolerance. In nonobese diabetic (NOD) mice, defects in central and peripheral tolerance are associated with a proliferative hyporesponsiveness of thymocytes and peripheral T cells elicited upon TCR activation. We investigated whether these defects in tolerance induction and hyporesponsiveness of NOD T cells manifest in an altered susceptibility to TCR-induced AICD. TCR-activated NOD splenic CD4 + and CD8 + T cells are more resistant to AICD than control strain C57BL/6, BALB/c, and NOR T cells. NOR CD4 + but not CD8 + T cells are resistant to TCR-induced AICD. Whereas c-FLIP expression is reduced in activated T cells from control strains, it persists in activated NOD CD8 + T cells and is accompanied by diminished activity of caspase-3 and -8. IL-4 reduces this c-FLIP expression and increases caspase-3 and -8 activity in activated NOD CD8 + T cells. Moreover, IL-4 and CD28 costimulation restores the susceptibility of NOD CD8 + T cells to AICD, and this is associated with increased expression of CD25, CD95, CD95L, and TNFR2. Thus, deficient activation of CD8 + T cells and their greater resistance to TCR-induced AICD may mediate defective peripheral tolerance and the development of T1D in NOD mice.