| 41. |
- Bekris, LM, et al.
(författare)
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Glutamate cysteine ligase catalytic subunit promoter polymorphisms and associations with type 1 diabetes age-at-onset and GAD65 autoantibody levels.
- 2007
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Ingår i: Exp Clin Endocrinol Diabetes. - : Georg Thieme Verlag KG. ; 115:4, s. 221-228
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of this study was to test the hypothesis that glutamate cysteine ligase catalytic subunit (GCLC) promoter polymorphisms are susceptibility factors for type 1 diabetes (T1D), T1D age-at-onset and T1D autoantibodies. T1D patients and control subjects from the Swedish Childhood Diabetes Registry and the Swedish Diabetes Incidence Study registry were genotyped for two GCLC promoter polymorphisms; the GCLC -129 C to T single nucleotide polymorphism (GCLC -129 SNP) and the GCLC GAG trinucleotide repeat polymorphism (GCLC TNR). Glutamate decarboxylase antibody (GAD65Ab) positive T1D patients with the GCLC -129 SNP C/T genotype have increased GAD65Ab levels (p-value, <0.05) compared to the GCLC -129 SNP C/C genotype. T1D patients with an age-at-onset of 14-35 years who possess the GCLC -129 SNP T/T genotype have a higher GAD65Ab index than T1D patients with the GCLC -129 SNP C/C genotype (p-value <0.05). In addition, T1D patients with an age-at-onset of 14-35 years possess the GCLC TNR 7/8 genotype at a lower frequency than the control subjects (OR, 0.33, 95% CI, 0.13-0.82). The GCLC -129 SNP and GCLC TNR appear to be in linkage disequilibrium (p-value<0.0001). These results suggest that GCLC promoter polymorphisms may influence GAD65Ab levels and may influence the age at which T1D is diagnosed.
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| 42. |
- Bekris, L. M., et al.
(författare)
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GAD65 autoantibody epitopes in adult patients with latent autoimmune diabetes following GAD65 vaccination
- 2007
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Ingår i: Diabetic Medicine. - : Wiley. - 1464-5491 .- 0742-3071. ; 24:5, s. 521-526
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Tidskriftsartikel (refereegranskat)abstract
- Aims Subcutaneous injection of recombinant human GAD65 (rhGAD65) in patients with latent autoimmune diabetes in adults (LADA) correlates with an increase in C-peptide levels. In this study we analysed the effect of rhGAD65 administration on the GAD65-specific autoimmune response. Methods Longitudinal serum samples obtained from LADA patients (n = 47) who received 4, 20, 100 or 500 mu g alum-formulated rhGAD65 or placebo by subcutaneous injection twice (4 weeks apart) were analysed for their epitope recognition using GAD65-specific recombinant Fab and GAD65/67 fusion proteins. Results Overall, minor changes in the epitope pattern were observed using either approach. Only in the 500-mu g dosage group was an increase in GAD65Ab level associated with a significant increase in the binding to a conformational epitope located at the middle part of GAD65. Conclusions Our data suggest that the apparent beneficial effects of 20 mu g alum-formulated recombinant human GAD65 is not explained by changes in the GAD65Ab epitope pattern.
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| 43. |
- Bekris, L M, et al.
(författare)
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Targeting type 1 diabetes before and at the clinical onset of disease.
- 2006
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Ingår i: Endocrine, Metabolic & Immune Disorders - Drug Targets. - : Bentham Science Publishers Ltd.. - 2212-3873 .- 1871-5303. ; 6:1, s. 103-124
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Tidskriftsartikel (refereegranskat)abstract
- Autoimmune type 1 diabetes is strongly associated with a number of immune abnormalities that manifest themselves before and at the time of clinical diagnosis. The clinical onset is associated with a major loss of the pancreatic islet beta cells. Insulin treatment is the only treatment option since numerous trials with agents that suppress or modulate immune function have failed to preserve beta cell function long term. Recent studies suggest that it is possible to predict clinical onset of diabetes by combining genetic with autoantibody testing. In this review we will summarize current and future drug targets for subjects at risk for type 1 diabetes as well as for subjects with recent onset disease. We will also discuss the possible importance of initiating as well as contributing factors such as reactive oxygen species and modified autoantigens. It is speculated that drug targets of factors important to disease pathogenesis may provide safe and effective adductive treatment to preserve beta cell function in autoantibody positive subjects who are at maximum risk for disease.
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| 44. |
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| 45. |
- Beyan, Huriya, et al.
(författare)
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Guthrie card methylomics identifies temporally stable epialleles that are present at birth in humans
- 2012
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Ingår i: Genome Research. - : Cold Spring Harbor Laboratory. - 1549-5469 .- 1088-9051. ; 22:11, s. 2138-2145
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Tidskriftsartikel (refereegranskat)abstract
- A major concern in common disease epigenomics is distinguishing causal from consequential epigenetic variation. One means of addressing this issue is to identify the temporal origins of epigenetic variants via longitudinal analyses. However, prospective birth-cohort studies are expensive and time consuming. Here, we report DNA methylomics of archived Guthrie cards for the retrospective longitudinal analyses of in-utero-derived DNA methylation variation. We first validate two methodologies for generating comprehensive DNA methylomes from Guthrie cards. Then, using an integrated epigenomic/genomic analysis of Guthrie cards and follow-up samplings, we identify interindividual DNA methylation variation that is present both at birth and 3 yr later. These findings suggest that disease-relevant epigenetic variation could be detected at birth, i.e., before overt clinical disease. Guthrie card methylomics offers a potentially powerful and cost-effective strategy for studying the dynamics of interindividual epigenomic variation in a range of common human diseases.
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| 46. |
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| 47. |
- Beyerlein, Andreas, et al.
(författare)
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Progression from islet autoimmunity to clinical type 1 diabetes is influenced by genetic factors : Results from the prospective TEDDY study
- 2019
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Ingår i: Journal of Medical Genetics. - : BMJ. - 0022-2593 .- 1468-6244. ; 56:9, s. 602-605
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Tidskriftsartikel (refereegranskat)abstract
- Background: Progression time from islet autoimmunity to clinical type 1 diabetes is highly variable and the extent that genetic factors contribute is unknown. Methods: In 341 islet autoantibody-positive children with the human leucocyte antigen (HLA) DR3/DR4-DQ8 or the HLA DR4-DQ8/DR4-DQ8 genotype from the prospective TEDDY (The Environmental Determinants of Diabetes in the Young) study, we investigated whether a genetic risk score that had previously been shown to predict islet autoimmunity is also associated with disease progression. Results: Islet autoantibody-positive children with a genetic risk score in the lowest quartile had a slower progression from single to multiple autoantibodies (p=0.018), from single autoantibodies to diabetes (p=0.004), and by trend from multiple islet autoantibodies to diabetes (p=0.06). In a Cox proportional hazards analysis, faster progression was associated with an increased genetic risk score independently of HLA genotype (HR for progression from multiple autoantibodies to type 1 diabetes, 1.27, 95% CI 1.02 to 1.58 per unit increase), an earlier age of islet autoantibody development (HR, 0.68, 95% CI 0.58 to 0.81 per year increase in age) and female sex (HR, 1.94, 95% CI 1.28 to 2.93). Conclusions: Genetic risk scores may be used to identify islet autoantibody-positive children with high-risk HLA genotypes who have a slow rate of progression to subsequent stages of autoimmunity and type 1 diabetes.
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| 48. |
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| 49. |
- Bogdani, Marika, et al.
(författare)
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Biobreeding rat islets exhibit reduced antioxidative defense and N-acetyl cysteine treatment delays type 1 diabetes
- 2013
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Ingår i: Journal of Endocrinology. - 1479-6805. ; 216:2, s. 111-123
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Tidskriftsartikel (refereegranskat)abstract
- Islet-level oxidative stress has been proposed as a trigger for type 1 diabetes (T1D), and release of cytokines by infiltrating immune cells further elevates reactive oxygen species (ROS), exacerbating beta cell duress. To identify genes/mechanisms involved with diabeto-genesis at the beta cell level, gene expression profiling and targeted follow-up studies were used to investigate islet activity in the biobreeding (BB) rat. Forty-day-old spontaneously diabetic lymphopenic BB DRlyp/lyp rats (before T cell insulitis) as well as nondiabetic BB DR+/+ rats, nondiabetic but lymphopenic F344lyp/lyp rats, and healthy Fischer (F344) rats were examined. Gene expression profiles of BB rat islets were highly distinct from F344 islets and under-expressed numerous genes involved in ROS metabolism, including glutathione S-transferase (GST) family members (Gstm2, Gstm4, Gstm7, Gstt1, Gstp1, and Gstk1), superoxide dismutases (Sod2 and Sod3), peroxidases, and peroxiredoxins. This pattern of under-expression was not observed in brain, liver, or muscle. Compared with F344 rats, BB rat pancreata exhibited lower GST protein levels, while plasma GST activity was found significantly lower in BB rats. Systemic administration of the antioxidant N-acetyl cysteine to DRlyp/lyp rats altered abundances of peripheral eosinophils, reduced severity of insulitis, and significantly delayed but did not prevent diabetes onset. We find evidence of b cell dysfunction in BB rats independent of T1D progression, which includes lower expression of genes related to antioxidative defense mechanisms during the pre-onset period that may contribute to overall T1D susceptibility.
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| 50. |
- Bogdani, Marika, et al.
(författare)
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Hyaluronan deposition in islets may precede and direct the location of islet immune-cell infiltrates
- 2020
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Ingår i: Diabetologia. - : Springer Science and Business Media LLC. - 1432-0428 .- 0012-186X. ; 63:3, s. 549-560
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Tidskriftsartikel (refereegranskat)abstract
- AIMS/HYPOTHESIS: Substantial deposition of the extracellular matrix component hyaluronan (HA) is characteristic of insulitis in overt type 1 diabetes. We investigated whether HA accumulation is detectable in islets early in disease pathogenesis and how this affects the development of insulitis and beta cell mass.METHODS: Pancreas tissue from 15 non-diabetic organ donors who were positive for islet autoantibodies (aAbs) and from 14 similarly aged aAb- control donors were examined for the amount of islet HA staining and the presence of insulitis. The kinetics of HA deposition in islets, along with the onset and progression of insulitis and changes in beta cell mass, were investigated in BioBreeding DRLyp/Lyp rats (a model of spontaneous autoimmune diabetes) from 40 days of age until diabetes onset.RESULTS: Abundant islet HA deposits were observed in pancreas tissues from n = 3 single- and n = 4 double-aAb+ donors (aAb+HAhigh). In these seven tissues, the HA-stained areas in islets measured 1000 ± 240 μm2 (mean ± SEM) and were fourfold larger than those from aAb- control tissues. The aAb+HAhigh tissues also had a greater prevalence of islets that were highly rich in HA (21% of the islets in these tissues contained the largest HA-stained areas [>2000 μm2] vs less than 1% in tissues from aAb- control donors). The amount of HA staining in islets was associated with the number of aAbs (i.e. single- or double-aAb positivity) but not with HLA genotype or changes in beta cell mass. Among the seven aAb+HAhigh tissues, three from single- and one from double-aAb+ donors did not show any islet immune-cell infiltrates, indicating that HA accumulates in aAb+ donors independently of insulitis. The three aAb+HAhigh tissues that exhibited insulitis had the largest HA-stained areas and, in these tissues, islet-infiltrating immune cells co-localised with the most prominent HA deposits (i.e. with HA-stained areas >2000 μm2). Accumulation of HA in islets was evident prior to insulitis in 7-8-week-old presymptomatic DRLyp/Lyp rats, in which the islet HA-stained area measured 2370 ± 170 μm2 (mean ± SEM), which was threefold larger than in 6-week-old rats. This initial islet HA deposition was not concurrent with beta cell loss. Insulitis was first detected in 9-10-week-old rats, in which the HA-stained areas were 4980 ± 500 μm2. At this age, the rats also exhibited a 44% reduction in beta cell mass. Further enlargement of the HA-positive areas (mean ± SEM: 7220 ± 880 μm2) was associated with invasive insulitis. HA deposits remained abundant in the islets of rats with destructive insulitis, which had lost 85% of their beta cells.CONCLUSIONS/INTERPRETATION: This study indicates that HA deposition in islets occurs early in type 1 diabetes and prior to insulitis, and points to a potential role of HA in triggering islet immune-cell infiltration and the promotion of insulitis.
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