Coronary artery disease (CAD) is the commonest cause of death. Here, we report an association analysis in 63,746 CAD cases and 130,681 controls identifying 15 loci reaching genome-wide significance, taking the number of susceptibility loci for CAD to 46, and a further 104 independent variants (r2 < 0.2) strongly associated with CAD at a 5% false discovery rate (FDR). Together, these variants explain approximately 10.6% of CAD heritability. Of the 46 genome-wide significant lead SNPs, 12 show a significant association with a lipid trait, and 5 show a significant association with blood pressure, but none is significantly associated with diabetes. Network analysis with 233 candidate genes (loci at 10% FDR) generated 5 interaction networks comprising 85% of these putative genes involved in CAD. The four most significant pathways mapping to these networks are linked to lipid metabolism and inflammation, underscoring the causal role of these activities in the genetic etiology of CAD. Our study provides insights into the genetic basis of CAD and identifies key biological pathways.
OBJECTIVEIn contrast with childhood-onset type 1 diabetes, the genetics of autoimmune diabetes in adults are not well understood. We have therefore investigated the genetics of diabetes diagnosed in adults positive for autoantibodies.RESEARCH DESIGN AND METHODSGAD autoantibodies (GADAs), insulinoma-associated antigen-2 antibodies (IA-2As), and islet cell autoantibodies were measured at time of diagnosis. Autoantibody-positive diabetic subjects (n = 1,384) and population-based control subjects (n = 2,235) were genotyped at 20 childhood-onset type 1 diabetes loci and FCRL3, GAD2, TCF7L2, and FTO.RESULTSPTPN22 (1p13.2), STAT4 (2q32.2), CTLA4 (2q33.2), HLA (6p21), IL2RA (10p15.1), INS (11p15.5), ERBB3 (12q13.2), SH2B3 (12q24.12), and CLEC16A (16p13.13) were convincingly associated with autoimmune diabetes in adults (P ≤ 0.002), with consistent directions of effect as reported for pediatric type 1 diabetes. No evidence of an HLA-DRB1*03/HLA-DRB1*04 (DR3/4) genotype effect was obtained (P = 0.55), but it remained highly predisposing (odds ratio 26.22). DR3/4 was associated with a lower age at diagnosis of disease, as was DR4 (P = 4.67 × 10−6) but not DR3. DR3 was associated with GADA positivity (P = 6.03 × 10−6) but absence of IA-2A (P = 3.22 × 10−7). DR4 was associated with IA-2A positivity (P = 5.45 × 10−6).CONCLUSIONSOur results are consistent with the hypothesis that the genetics of autoimmune diabetes in adults and children are differentiated by only relatively few age-dependent genetic effects. The slower progression toward autoimmune insulin deficiency in adults is probably due to a lower genetic load overall combined with subtle variation in the HLA class II gene associations and autoreactivity.
Aims/hypothesis. Diabetic retinopathy is a frequent microvascular complication. In search of novel risk markers, we analysed the association between serum levels of the major advanced glycation end product N ε -carboxymethyl-lysine (CML) and prevalence of advanced stages of retinopathy in Type 2 diabetic patients without nephropathy. Methods. We carried out a case-control study of Type 2 diabetic patients with and without advanced stages of diabetic retinopathy. Retinopathy and macular oedema were defined according to standard criteria. Serum levels of CML were estimated by means of a novel competition-based ELISA assay. Results. Serum levels of CML were significantly different between age-matched controls (n=792; mean value ± SD: 521±134 ng/ml), Type 2 diabetic patients without severe retinopathy (821±141 ng/ml; p<0.0001) and Type 2 diabetic patients with proliferative retinopathy (1182±346 ng/ml; p<0.0001). Levels of CML greater than 1000 ng/ml represented a 25-fold increase in risk of proliferative retinopathy. Receiver operating characteristics analysis revealed a CML threshold of 1087 ng/ml (100% sensitivity, 93% specificity) for clinically significant macular oedema. Conclusions/interpretation. High serum levels of CML were associated with advanced stages of retinopathy. Serum levels were shown to be a progressive risk marker, whereby a level of more than 1000 ng/ml induced a 25-fold increase in risk of proliferative retinopathy and clinically significant macular oedema. Our data suggest that serum levels of CML provide a novel risk marker for advanced stages of diabetic retinopathy in Type 2 diabetic patients.
Significance In type 1 diabetes (T1D), the insulin-producing pancreatic β-cells are destroyed by the immune system. Both genetic and environmental factors contribute to T1D risk. Candidate genes for T1D identified by genome-wide association studies have been proposed to act at both the immune system and the β-cell levels. This study shows that the risk variant rs3825932 in the candidate gene cathepsin H ( CTSH ) predicts β-cell function in both model systems and human T1D. Collectively, our data indicate that higher CTSH expression in β-cells may protect against immune-mediated damage and preserve β-cell function, thereby representing a possible therapeutic target. Our study reinforces the concept that candidate genes for T1D may affect disease progression by modulating survival and function of the β-cells.
Aims/hypothesis. Retinopathy is the most common microvascular complication of diabetes. Our aim was to address the predictive value of pro-angiogenic and anti-angiogenic markers for progression of retinopathy. Methods. Aqueous humor was collected at cataract surgery from 32 diabetic patients who had no or very mild retinopathy (ETDRS stage ≤20) and 33 normoglycaemic control subjects. Content of pro-angiogenic vascular endothelial growth factor and angiogenic inhibitor pigment epithelium-derived factor were determined. Angiogenic activity was quantified by measuring its effect on the migration of capillary endothelial cells. The predictive value of the initial level of these markers for progression of retinopathy was studied by following the probands for a maximum of 75 months. Results. In the aqueous fluid content of vascular endothelial growth factor was increased in diabetic patients (mean values 492 versus 292 pg/ml; p=0.0052), and pigment epithelium-derived factor values were decreased (mean values 1740 versus 3680 ng/ml; p=0.0058) compared to control subjects. Of the diabetic patients ten progressed during follow-up (ETDRS
Aims/hypothesis. Preproinsulin is a target T cell autoantigen in human Type 1 diabetes. This study analyses the phenotype and epitope recognition of preproinsulin reactive T cells in subjects with a high genetic risk of diabetes [HLA-DRB1*04, DQ8 with Ab+ (auto-antibody-positive) or without islet autoantibodies (control subjects)], and in HLA-matched diabetic patients. Methods. A preproinsulin peptide library approach was used to screen for cytokine profiles and epitope specificities in human peripheral blood lymphocytes, and CD4 + CD45RA − and CD4 + CD45RA + T cell subfractions, representing memory and naive and recently primed T cells respectively. Results. In CD4 + T cell subsets we identified immunodominant epitopes and cytokine production patterns that differed profoundly between patients, Ab+ subjects and non-diabetic HLA-matched control subjects. In Ab+ subjects, a C-peptide epitope C13-29 and insulin B-chain epitope B11-27 were preferentially recognised, whereas insulin-treated Type 1 diabetic patients reacted to native insulin and B-chain epitope B1-16. In peripheral blood lymphocytes of Ab+ subjects, an increase in T helper (Th) 1 (IFNγ, IL-2) and Th2 (IL-4) cytokines was detectable, wheras in CD45RA + and CD45RA − subsets, IL-4 and IL-10 phenotypes dominated, compatible with the contribution of non-CD4 cells to IFNγ content. In insulintreated Type 1 diabetic patients, naive and recently primed CD4 + cells were characterised by increasd IFNγ, TNFα, and IL-5. Conclusions/interpretation. Our data show that T cell reactivity to preproinsulin in CD45RA subsets is Th2-dominant in Ab+ subjects, challenging the Th1 paradigm in Type 1 diabetes. Characteristic immunodominant epitopes and cytokine patterns distinguish diabetic patients and Ab+ subjects from HLAmatched healthy individuals. This could prove useful in monitoring of T-cell immunity in clinical diabetes intervention trials. [Diabetologia (2004) 47:439-450]
Recently, we have identified proinsulin (P-Ins)73-90 as an immunodominant T cell epitope of HLA-DRB1*0401 (DR4) subjects with -islet cell autoimmunity and of HLA-DR4͞CD4 double-transgenic mice immunized with human P-Ins. We have compared the fine specificities of one human CD4 T cell clone and two mouse T cell hybridoma clones recognizing this epitope, and, although these three clones all recognized the same core region (LALEGSLQK), there were major differences in how they interacted with the peptide (p)͞HLA complex, reflecting the fact that human P-Ins is a foreign antigen in the mouse and an autoantigen in the type 1 diabetes patient. The human T cell clone was forkhead transcription factor 3 (Foxp3)-positive, a marker for regulatory T cell lineages, and secreted predominantly IL-5, IL-10, and low levels of IFN␥ in response to P-Ins73-90. This finding is compatible with the previously detected regulatory cytokine pattern in subjects with -cell autoimmunity. However, added N-or C-terminal amino acids drastically changed HLA and tetramer binding capacity as well as T cell reactivity and the cytokine phenotype of the P-Ins 73-90-specific human CD4 T cell clone, suggesting a potential for this P-Ins epitope as a target for therapeutic intervention in HLA-DR4-positive humans with -islet cell autoimmunity or recent-onset type 1 diabetes.Foxp3 ͉ HLA-DRB1*0401 ͉ type 1 diabetes P roinsulin (P-Ins) is considered an important autoantigen in type 1 diabetes (T1D), because it is the only truly -cellspecific target, and because autoreactivity to P-Ins is very common in T1D patients with the HLA-DRB1*0401 (DR4) DQ8 haplotype (1-6). The differences distinguishing autoreactive from foreign antigen reactive T cell responses to the same immunogenic epitope are still largely unknown (7). To understand the structural requirements for activation of self-reactive P-Ins 73-90 -specific T cells in T1D autoimmunity, we have isolated a Foxp3-positive CD4 ϩ T cell clone from a DR4-homozygous T1D patient and compared the fine specificity of this T cell receptor to those of two murine T cell hybridoma clones derived from HLA-DR4 transgenic mice, in which this epitope is a foreign antigen (8). P-Ins 73-90 is situated at the C terminus of the C peptide and also covers the enzymatic cleavage site of the insulin A chain (8). This site is proteolytically destroyed during the maturation of insulin before secretion and is, therefore, an indication that Proinsulin and not Insulin may be the actual autoantigenic target in T1D.In human studies using purified CD4 ϩ T cells from HLA-DR4-positive subjects with islet autoimmunity, P-Ins 73-90 was also identified as an immunodominant epitope. This epitope was recognized by approximately two thirds of autoantibody-positive subjects, one third of recently diagnosed T1D patients, and a few control subjects (5, 9). The cytokines seen in response to P-Ins 73-90 were predominantly IL-4 and IL-10 in subjects with -cell autoimmunity (9). Moreover, in a consecutive follow up of three high-risk individuals, ...
T2DM was confirmed in about 90% of patients while about 10% with β-cell autoimmunity or HLA-DR genetic risk likely had either T1.5DM or 'double diabetes' or an unknown diabetes type.
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