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Query: UMLS:C0011849 (diabetes)
 277,896 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Genetic factors and environmental factors are thought to be involved in the pathogenesis of insulin-dependent diabetes mellitus Type 1. Viruses, as one environmental factor, may act as primary injurious agents to beta cells or as triggering agents for autoimmunity. Some viruses such as EMC-D and Coxsackie B4 can induce Type 1 diabetes by infecting and destroying beta cells in genetically susceptible mice. In addition, certain species of monkey, such as Patas, show elevated blood glucose levels and depressed insulin secretion after infection with Coxsackie B4 virus. An occasional case of Type 1 diabetes mellitus appears to be associated with the infection of beta cells with Coxsackie B viruses. In addition, Coxsackie B4 virus may also generate viral antigen-specific cytotoxic T cells which may cross-react with a beta cell-specific autoantigen leading to autoimmune Type 1 diabetes. In the case of viral triggering of autoimmune Type 1 diabetes, certain viruses (eg, retrovirus in NOD mice and rubella virus in hamsters and humans) may alter a normally existing beta cell antigen into an immunogenic form or might induce a new antigen, leading to beta cell-specific autoimmune insulin dependent diabetes mellitus. In addition, other viruses (eg, Kilham's rat virus in DR-BB rats) could generate antigen-specific T effector cells which may cross-react with a beta cell-specific autoantigen. In contrast to the induction of diabetes, viruses can prevent the development of diabetes. Inoculation of DP-BB or NOD mice with lymphocytic choriomeningitis virus reduced the incidence of diabetes or prevented the disease by disordering particular lymphocyte subsets.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Induction and prevention of type 1 diabetes mellitus by viruses. 129 46

The GABA-producing enzyme glutamate decarboxylase (GAD) is a prominent autoantigen in insulin-dependent diabetes mellitus (IDDM). Autoantibodies against GAD were found with a high prevalence in IDDM patients and in animal models for IDDM. The aim of this study was to detect autoantibodies against both isoforms of GAD in diabetic and non-diabetic but diabetes-prone BB/OK rats by Western blotting and to test their specificity to GAD by an immuno-trapping enzyme activity assay. Eighteen diabetic and 18 non-diabetic BB/OK rats (age 121 +/- 20 days) were investigated. In 10/18 (56%) of the diabetic and 13/18 (72%) of the non-diabetic BB/OK rats autoantibodies against at least one GAD-isoform were detected by Western blotting. In the immunotrapping enzyme activity assay, the mean value of the diabetic (1151 +/- 552 cpm, n = 11) and nondiabetic BB/OK rats (1978 +/- 1213 cpm, n = 10) was significantly (p < 0.01) increased compared to the LEW. 1A control rats (581 +/- 274 cpm, n = 12). 7/10 (70%) individual sera of the non-diabetic and 5/11 (45%) of the diabetic BB/OK rats were positive in this test. In conclusion, the prevalence of GAD autoantibodies in BB/OK rat is connected with the genetic susceptibility to IDDM but is not a predictor for the onset of the disease in BB/OK rats.
Diabetes Res 1992
PMID:Detection of antibodies against both isoforms of glutamate decarboxylase in BB/OK rats by western blotting and immuno trapping enzyme activity assay. 134 8

Prophylactic insulin treatment is effective in preventing diabetes in animal models of insulin-dependent diabetes mellitus (IDDM) but the safety of such preventive treatment in prediabetic human subjects remains unclear; insulin is a potential autoantigen that could accelerate beta-cell decompensation and onset of IDDM. We have investigated whether insulin treatment of non-diabetic subjects increases the risk of subsequent development of diabetes in a retrospective study of Danish patients who received insulin-shock treatment for psychiatric disorders. Mean age of the 481 patients at insulin-shock treatment was 32.6 (range 12.9-69.6) years. The patients received 59 (6-200) injections of 78 (16-261) IU bovine/porcine insulin. Hospital records provided an average of 22.0 (0.6-51.2) years' observation. During the observation time, IDDM developed in only 1 patient; 1.3 cases would be expected from Danish incidence data (p = 0.75). Similarly, there was no significant difference between the observed number of cases of non-insulin-dependent diabetes mellitus (NIDDM) and the number expected from Danish prevalence data (12 vs 10.2; p = 0.45). We collected blood samples from 27 of the patients. All but 2 (who had previously diagnosed NIDDM) had normal fasting blood glucose and plasma insulin concentrations, none had islet-cell antibodies, and only 2 had detectable insulin antibodies. Thus, the risk of diabetes was not increased by the use of many insulin injections in these non-diabetic subjects. We conclude that clinical trials on prevention of IDDM by prophylactic insulin treatment can be regarded as safe.
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PMID:No risk of diabetes after insulin-shock treatment. 135 43

GAD is an autoantigen in IDDM. Molecular cloning and specific antibodies allowed us to demonstrate that only the lower M(r) GAD64 isoform is expressed in human islets, in contrast to human brain, rat islets, and rat brain, all of which express both GAD64 and GAD67. Expression of the human islet GAD64 isoform in COS-7 and BHK cells resulted in an enzymatically active rGAD64, which is immunoreactive with diabetic sera comparable with that of the islet 64,000-M(r) autoantigen. Immunoprecipitation analyses showed that 21/28 (75%) IDDM sera had rGA D64 antibodies compared with only 1/59 (1.7%) of the healthy control sera. In immunoblot analyses, an SMS serum--but only 1/10 randomly selected IDDM sera--recognized the blotted rGAD64 without relation to immunoprecipitation titers. In conclusion, only the GA D64 isoform is expressed in human islets, in contrast to rat islets, which also express the GAD67 isoform. The immunological properties of human rGAD64 are comparable with the native 64,000-M(r) islet autoantigen, allowing further studies of the immunopathogenesis of IDDM.
Diabetes 1992 Oct
PMID:Recombinant glutamic acid decarboxylase (representing the single isoform expressed in human islets) detects IDDM-associated 64,000-M(r) autoantibodies. 139 11

During cell differentiation in the thymus, self-reactive T cells can be generated. The majority of these seem to be deleted after intrathymic encounter with the relevant autoantigen. As all self antigens are unlikely to be present in the thymus, some autoreactive T cells may escape censorship. Here we study the fate of these cells using transgenic mice expressing the class I molecule H-2Kb (Kb) in the insulin-producing beta-cells of the pancreas. These mice were crossed with mice transgenic for genes encoding a Kb-specific T-cell antigen receptor (TCR) which could be detected using a clonotype-specific monoclonal antibody. Although T cells expressing the highest level of transgenic TCR were deleted intrathymically in double-transgenic mice, Kb-specific T cells were detected in the periphery. These cells caused the rejection of Kb-expressing skin grafts, but ignored islet Kb antigens even after priming. But when double-transgenic mice were crossed with transgenic mice expressing the lymphokine interleukin-2 in the pancreatic beta-cells, there was a rapid onset of diabetes. These results indicate that autoreactive T cells that ignore self antigens may cause autoimmune diabetes when provided with exogenous 'help' in the form of interleukin-2.
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PMID:Autoimmune diabetes as a consequence of locally produced interleukin-2. 140 74

Recent studies in NOD mice suggest that cellular and humoral responses against beta cell protein(s) cross-reactive with mycobacterial heat-shock protein, hsp60, are implicated in the development of autoimmune diabetes. However, this putative, hsp60-related autoantigen has not yet been identified nor have the preceding events triggering the autoimmunity against it. Our recent studies show that antibodies to the mammalian hsp60 bind specifically to the 62 kDa protein located to insulin secretory granules and mitochondria of pancreatic beta cells of healthy mice [1]. In islets of prediabetic NOD mice affected by insulitis, the cellular distribution of this hsp60-related antigen was found to be altered. In the present report, we have examined whether this endogenous hsp60-related protein of secretory granules serves as an autoantigen in type I diabetes. The results of Western blot analysis indicate that diabetic mice sera show reactivity to a 62 kDa islet cell antigen. The NOD mice sera that were positive in detection of the 62 kDa islet cell antigen were also able to recognize the recombinant human hsp60. Immunogold electron microscopy revealed that diabetic NOD mouse sera, cross-reactive to human recombinant hsp60, recognize the antigen located in secretory granules of beta cells. Double-immunogold labelling demonstrated that antigens recognized by both diabetic NOD mice sera and monoclonal hsp60 antibodies co-localized in the same secretory granules of beta cells. Preincubation of islet cell sections with one type of antibody blocks subsequent binding of the other, indicating that epitopes recognized by both antisera on these proteins are shared. Moreover, preadsorption of diabetic sera with the recombinant human hsp60 abolished labelling of secretory granules. These results indicate that the hsp60-related protein of beta cell secretory granules is an autoantigen in type I diabetes in NOD mice.
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PMID:Secretory granule autoantigen in insulin-dependent diabetes mellitus is related to 62 kDa heat-shock protein (hsp60). 141 89

Since their demonstration in 1975, ICSAs have been proposed as serological markers and pathogenic elements in IDDM. ICSAs are detected in the sera of most newly diagnosed IDDM patients by indirect IFL that uses viable preparations of rat islet or insulinoma cells as substrate, but they also can be detected by using human insulinoma or fetal islet cells. We have tried to demonstrate ICSAs in the sera of 31 newly diagnosed diabetic patients, including 6 positive samples on human fetal islet cells, which used their natural target for the first time: normal human islet cells. In spite of using different types of preparations of these cells (i.e., freshly dispersed cell suspensions, monolayer cultures, or dispersed islets after culture), ICSAs could not be detected by IFL under the UV microscope, nor by flow cytometry. In contrast, 9 of 29 of the sera gave a positive staining on the RIN rat insulinoma cells. In an attempt to establish whether the putative ICSA autoantigen is present in the surface of human islet cells in the diabetic pancreas, the insulitis microenvironment was emulated by exposing the islets to three types of stress: 1) cytokines (IFN-gamma and TNF-alpha); 2) heat shock; and 3) hyperglycemia. However, diabetic sera failed again to recognize membrane antigens on the islet cells after either of these treatments. Neither were islet cells from a newly diagnosed diabetic patient stained by its autologous serum (ICA titer > 80 JDF U). These results suggest that ICSA autoantigen is not expressed in the membrane of human islet cells and therefore raises doubts about their proposed pathogenic role.
Diabetes 1992 Dec
PMID:Reevaluation of autoantibodies to islet cell membrane in IDDM. Failure to detect islet cell surface antibodies using human islet cells as substrate. 144 4

Autoimmune diseases result from the activation of self-reactive T cells induced by autoantigens or by foreign antigens cross-reactive with an autoantigen. A striking characteristic of autoimmune diseases is the increased frequency of certain HLA alleles in affected individuals. Moreover, as demonstrated for example in rheumatoid arthritis and insulin-dependent diabetes mellitus, class II alleles positively associated with autoimmune diseases share amino acid residues in the hypervariable HLA regions involved in peptide binding. Therefore, it is likely that disease-associated HLA class II molecules have the capacity to bind the autoantigen and present it to T cells, thereby inducing and maintaining, under appropriate conditions, the autoimmune disease. The data reviewed here demonstrate MHC-selective inhibition of antigen-induced T cell responses in vivo by parenterally administered soluble, MHC-binding peptide competitors, under conditions in which the competitor is not immunogenic. This suggests the feasibility of a therapeutic approach based on blockade of MHC class II molecules in the treatment of HLA-linked autoimmune diseases.
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PMID:Inhibition of T cell activation by MHC blockade: a possible strategy for immunointervention in autoimmune diseases. 150 37

This study examined the relationship between insulin secretion and expression of the 64 kDa/glutamic acid decarboxylase autoantigen in pancreatic islets. Islets isolated from Wistar rats were cultured for 3 days under different conditions: in 5.5 mmol/l glucose with or without alpha-ketoisocaproic acid or glipizide and in 28 mmol/l glucose with or without diazoxide. The 64 kDa/glutamic acid decarboxylase autoantigen was precipitated from lysates of [35S]-methionine-labelled islets with sera from patients with Type 1 (insulin-dependent) diabetes mellitus and identified by sodium dodecyl sulphate-polyacrylamide gel electrophoresis and fluorography. In parallel, insulin contents of the islets and the media were determined as well as the rates of glucose-stimulated (pro)insulin biosynthesis. alpha-Ketoisocaproic acid and glipizide were found to stimulate the expression of the 64 kDa/glutamic acid decarboxylase autoantigen and also the rate of insulin secretion. Diazoxide on the other hand reduced the rate of the 64 kDa/glutamic acid decarboxylase autoantigen synthesis in parallel with an inhibition of glucose-stimulated insulin release. Under most of the conditions employed, (pro)insulin biosynthesis was not affected. The correlation found between the rate of insulin release and expression of the 64 kDa/glutamic acid decarboxylase autoantigen might provide an explanation for the earlier observed relationship between the functional demands on the Beta cells and their rate of destruction which may result in diabetes.
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PMID:Expression of the 64 kDa/glutamic acid decarboxylase rat islet cell autoantigen is influenced by the rate of insulin secretion. 152 32

Autoimmunity is likely the cause of a variety of diseases including systemic lupus erythematosus, rheumatoid arthritis and diabetes. Normally, the body's immune system serves as a defense against a variety of conditions, including, injury, infection and neoplasm. However, for reasons that are currently unclear, the normal regulation of the immune system can breakdown resulting in autoaggressive responses. T cells, especially CD4+ cells, appear to play a predominant role in most autoimmune diseases. We summarize our workshop which focussed on the role of the T cells in autoimmune diseases. We summarize our workshop which focussed on the role of the T cells in autoimmune diseases; the T cell receptor in autoantigen recognition (emphasizing the role of selective T cell receptor V regions in the autoimmune response); and a discussion of possible therapeutic interventions.
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PMID:The T cell receptor in autoimmune diseases. 153 79


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