Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0011849 (diabetes)
 277,896 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The enzyme glutamic acid decarboxylase (GAD65) is a major autoantigen in insulin-dependent diabetes mellitus (IDDM). To study T-cell reactivity towards GAD, peripheral blood leucocytes from seven patients with IDDM and five control subjects were stimulated in vitro with recombinant GAD. All diabetics studied were heterozygous for diabetes-associated HLA alleles, i.e. HLA-DRB1*03,*04-DQB1 *0302,*0201. A single IDDM subject (no. GAD65.05) revealed a strong response against GAD65. After stimulation, his T-cell receptor beta (TCRBV) usage was found to be oligoclonal. The sequence analysis of the putative peptide binding region of the T-cell receptor (CDR3 region) of 37 GAD-reactive T-cell clones revealed no common CDR3 motif. The stimulation of GAD-reactive T-cells could be inhibited with anti-class II monoclonal antibodies, indicating a class II restricted T-cell response. In addition, GAD65-responsive T-cells revealed a Th1 cytokine response pattern. The author's data suggest that GAD-reactive T-cells of Th1 phenotype can be obtained after in vitro stimulation of peripheral blood leucocytes from an HLA-DRB1*03/*04 heterozygous IDDM patient. The lack of a common CDR3 motif suggests the absence of an immunodominant T-cell epitope in that patient, or may indicate receptor repertoire spreading of peripheral T-lymphocytes.
 ...
PMID:In vitro stimulation with glutamic acid decarboxylase (GAD65) leads to an oligoclonal response of peripheral T-cells in an IDDM patient. 855 91

A better knowledge of the pathogenesis of type 1 diabetes (IDDM) may open the road to the prevention of the diseases. Primary prevention is meant to identify susceptible subjects, either soon after birth or before the immunological aggression of beta cells. The practical approach in this respect is very difficult because multiple obstacles must be overcome. Secondary prevention involves subjects who already show immunological or metabolic alterations, as the presence of ICA, antiinsulin antibodies, GAD antibodies and a defect of the first phase of insulin secretion. Most authors attach great interest to trials with insulin and nicotinamide. Insulin seems to reduce antigen expression when beta cells are damaged. Nicotinamide exerts a protection toward diabetes in animals, and, as scavanger of free radicals, facilitates beta cell regeneration. Research is going on, all over the world, and special multicenter trials are in progress both in the USA and Europe.
 ...
PMID:[Prevention of juvenile diabetes (type 1): reality or fiction?]. 856 82

Glutamic acid decarboxylase is attracting much interest because of its putative involvement in two clinical disorders: stiffman syndrome and insulin-dependent diabetes. Here we discuss the clinical significance of an autoimmune response against GAD and consider how such information may help identify the disease mechanisms of these disorders.
 ...
PMID:The clinical significance of an autoimmune response against glutamic acid decarboxylase. 857 52

To help elucidate the mode of inheritance of insulin-dependent diabetes mellitus (IDDM), we measured GAD (glutamic acid decarboxylase) autoantibodies (GAD65Ab), insulin autoantibodies (IAA), and cytoplasmic islet cell autoantibodies (ICA) in 292 sequentially screened non-diabetic offspring of patients with IDDM. The prevalence of these islet autoantibodies was higher in offspring of diabetic fathers than in offspring of diabetic mothers. The prevalences of GAD65Ab, IAA, and ICA in the offspring of diabetic fathers were 11.5%, 10.8%, and 8.1% vs 2.1%, 1.4%, and 2.8%, respectively in the offspring of diabetic mothers (p < 0.002, p < 0.001, and p = 0.06 NS). Amongst autoantibody-positive relatives the IAA and ICA levels were significantly higher in offspring of diabetic fathers than of diabetic mothers (p < 0.002 and p < 0.01, respectively). The frequencies of these autoantibodies were equal in male and female offspring. We conclude that IDDM mothers transmitted islet autoimmunity less frequently to their offspring than IDDM fathers. Given the markedly lower frequency of autoantibodies in offspring of mothers, larger sample sizes will be required to determine whether islet autoantibodies are influenced by age of IDDM onset of mothers, maternal age of pregnancy, and presence of diabetes in these mothers prior to conception.
 ...
PMID:Sexual dimorphism in transmission of expression of islet autoantibodies to offspring. 858 46

We have defined and characterized the natural history of spontaneous near-normoglycemic remission off of antidiabetic medication in 79 black NIDDM subjects. They had initially presented with plasma glucose levels of 37.8 +/- 19.3 mmol/l. Baseline clinical metabolic and 8-year prospective data were obtained (51 men and 28 women, mean age 45 +/- 10 years, islet-cell or GAD antibody negative). After hospitalization and intensive outpatient treatment, near-normoglycemic remission (fasting plasma glucose 6.1 +/- 0.83 mmol/l and HbA1c 0.95 +/- 0.10 of upper limit of normal) occurred within 8 +/- 10 months of insulin or sulfonylurea therapy. This was unrelated to the resolution of stress or significant weight loss (1.9 +/- 4.97 kg). Metabolic studies performed during remission showed 17% normal, 33% impaired, and 50% diabetic glucose tolerance. Glucose disposal (1 mU x kg-1 x min-1) euglycemic insulin clamp with D-[3(-3)H]glucose) was higher in the normal glucose tolerance group compared with the impaired and diabetic groups (37.8 +/- 10.2 vs. 26.1 +/- 10.7 and 26.7 +/- 12.0 micromol x kg-1 x min-1; P < 0.05) despite similar BMIs in all three groups (28.8 +/- 3.7 kg/m2). Insulin secretion was below the normal range. Of 79 patients, 27 relapsed. A Kaplan-Meier survival analysis gives a median time of 40 months to relapse. Higher presenting plasma glucose and male sex predicted earlier relapse. Near-normoglycemic remission may occur in up to 30% of black new-onset NIDDM patients. It appears to be associated with intensive initial glycemic regulation and may be a method of decreasing the development of microvascular complications in NIDDM.
Diabetes 1996 Mar
PMID:Long-term normoglycemic remission in black newly diagnosed NIDDM subjects. 859 39

One of the major beta-cell autoantigens associated with IDDM is GAD. Although GAD expression has been detected in adult islets, transcriptional expression of the GAD genes has not been reported during human pancreatic ontogeny. We therefore analyzed patterns of GAD gene transcription by quantitating the mRNAs encoding both the 65- and 67-kDa isoforms (GAD65 and GAD67, respectively) in human fetal, postnatal, and adult pancreases, as well as in isolated adult islets, and examined their tissue-specific expression. Significant levels of pancreatic GAD65 transcripts were already detected at 13 weeks of gestation and were expressed at higher levels in the fetal and infantile pancreas than in the adult pancreas. Isolated adult pancreatic islets were highly enriched in GAD65 mRNA. In contrast, GAD67 transcripts were not detectable in fetal and postnatal pancreases. In addition to the pancreas, marked GAD expression was detected in the brain, whereas other tissues examined contained either low or undetectable GAD transcripts. Triple immunofluorescent staining of fetal and adult pancreases revealed colocalization of GAD65 with alpha- and beta-cells. In the fetal pancreas, strong immunoreactivity for GAD65 was also evident in epithelial cells, which lacked expression of insulin or glucagon, some of which were present in the ductal epithelium, suggesting that GAD65 expression might correlate with endocrine determination. In summary, 1) this is the first demonstration of GAD65 expression in the human fetal pancreas, implicating a potential role during islet development, and 2) GAD65 may be a useful marker for the identification of primitive islet cells.
Diabetes 1996 Apr
PMID:Ontogeny and tissue distribution of human GAD expression. 860 72

We report a pilot study to determine the preventive effect of small doses of insulin injected subcutaneously on slowly progressive beta-cell damage in islet cell antibody (ICA)-positive patients with apparent NIDDM. Ten NIDDM patients who were ICA' were divided into two groups of five. In the insulin group (age: 51 +/- 8 years [mean +/- SD], sex: 3 men and 2 women), intermediate-type insulin (3-16 U/day) was given once or twice daily as a subcutaneous injection. The sulfonylurea (SU) group (age: 48 +/- 11 years, sex: 3 men and 2 women) was initially treated with a SU agent. Changes in beta-cell function, as indicated by serum C-peptide responses and blood glucose values during a 100-g oral glucose tolerance test, as well as ICA and GAD antibody status, were evaluated for up to 30 months in both groups. ICA status became negative in four of five patients in the insulin group. ICA status did not become negative in any of the patients in the SU group (P = 0.047 vs. insulin group). ICA status was persistently positive in two patients whose beta-cell function eventually progressed to an insulin-dependent state and fluctuated in the remaining three patients. In the insulin group, GAD antibody status became negative in one of four initially GAD antibody-positive NIDDM patients. In the SU group, GAD antibody status was persistently positive in three NIDDM patients (NS vs. insulin group). The serum C-peptide response improved significantly within 6 and 12 months in the insulin group, whereas it decreased progressively in the SU group. The changes in C-peptide response were significantly different between the two groups at 6, 12, 24, and 30 months. Two-hour blood glucose and HbA1 values were unchanged in the insulin group, but they increased in the SU group. Subcutaneous small doses of insulin, resulting in a high rate of negative conversion of ICA and an improved serum C-peptide response, may be effective in treating ICA+ NIDDM patients who are at high risk for slowly progressive beta-cell failure.
Diabetes 1996 May
PMID:Small doses of subcutaneous insulin as a strategy for preventing slowly progressive beta-cell failure in islet cell antibody-positive patients with clinical features of NIDDM. 862 Oct 13

The 65 kDa isoform of glutamic acid decarboxylase (GAD 65) is an autoantigen implicated in type I diabetes. We have developed a quantitative PCR method to measure GAD 65 mRNA in the pancreas of nonobese diabetic (NOD) mice. Two other nonautoimmune mouse strains were used as controls. In all mice, pancreatic GAD 65 expression declined with age. In 5-week-old NOD mice, a clear difference was detected between males and females. This sexual dimorphism may explain the absence of tolerance to GAD 65 in the NOD female which could contribute to autoimmune destruction of beta cells in the pancreas and subsequent development of diabetes.
 ...
PMID:Gene expression of pancreatic glutamic acid decarboxylase in the nonobese diabetic mouse. 864 17

Islet cell antibodies (ICAs) are predictive of type I diabetes in first-degree relatives, but this immunohistochemical assay has proven difficult to standardize. As an alternative, we assessed the use of radioassays for antibodies against three molecularly characterized islet autoantigens, including ICA512bdc (amino acid residues 256-979 of the IA-2 molecule, incorporating the intracellular domain). We measured insulin autoantibodies (IAAs), GAD autoantibodies (GAAs), and ICA512bdc autoantibodies (ICA512bdcAAs) by radioassay, in addition to ICAs, in 882 first-degree relatives of patients with type I diabetes, 50 of whom later developed diabetes with a median follow-up of 2.0 years (maximum 11.3 years). The cutoff for each radioassay was determined by testing >200 control subjects. When autoantibody frequencies among the relatives were analyzed according to relationship to the proband, the offspring of diabetic fathers had a higher frequency of ICA5I2bdcAAs (P = 0.008), IAAs (P = 0.0001) and GAAs (P = 0.0001) than the offspring of diabetic mothers. ICA512bdcAAs and IAAs both showed a significant association with HLA-DR4-DQ8 (P = 0.0005). Among relatives developing diabetes, 98% had one or more of IAAs, GAAs, or ICA512bdcAAs, and 80% had two or more of these autoantibodies, compared with none of the control subjects. Using survival analysis to allow for different lengths of follow-up, there was a significant increase in the risk of diabetes with the number of these autoantibodies present, comparing zero, one, two, and three autoantibodies (P < 0.0001, log-rank test), and by Cox regression analysis, this was independent of ICAs and age. For relatives with two or more of these autoantibodies, the risk of diabetes within 3 years was 39% (95% CI, 27-52) and the risk within 5 years was 68% (95% CI, 52-84). Relatives with all three autoantibodies had a risk within 5 years estimated to be 100%. The presence of low first-phase insulin release further increased the risk for relatives with one or two autoantibodies. We conclude that the presence of two or more autoantibodies (out of IAAs, GAAs, and ICA512bdcAAs) is highly predictive of the development of type I diabetes among relatives.
Diabetes 1996 Jul
PMID:Prediction of type I diabetes in first-degree relatives using a combination of insulin, GAD, and ICA512bdc/IA-2 autoantibodies. 866 44

IDDM results from immune-mediated destruction of insulin-producing pancreatic beta-cells in individuals genetically susceptible for the disease. There is evidence that the 65-kDa isoform of GAD plays a critical role in the induction of autoimmune diabetes in NOD mice. In humans, it is still unclear when and to what beta-cell antigens autoreactive lymphocytes become activated during early disease. We conducted a prospective study from birth, BABY-DIAB, among children of mothers with IDDM or gestational diabetes or fathers with IDDM, and we investigated the temporal sequence of antibody responses to islet cells (ICA), insulin (IAA), GAD (GADA), and the protein tyrosine phosphatase IA-2/ICA512 (IA-2A). Of 1,019 children included at birth, we have currently followed 513 to the age of 9 months, 214 to the age of 2 years, and 37 to the age of 5 years. At birth, all antibody specificities were frequent in newborns of diabetic mothers but not fathers and are suggested to be transplacentally acquired because they are strongly correlated with antibody levels in their diabetic mothers. In early childhood, antibody levels were <99th percentile of control subjects in the majority of children. However, 37 children exhibited elevated antibody levels; these were most frequently detected at the age of 2 years. The antibody prevalence at age 2 years was 2.3% for ICA, 7% for IAA, 4.2% for GADA, and 2.8% for IA-2A (8.9% positive for at least one antibody). Children of diabetic fathers were positive for at least one antibody more frequently than were children of diabetic mothers (9 months of age: 8.5 vs. 3.6%; 2 years of age: 16.7 vs. 7.9%). There was no specific sequence in the appearance of positive autoantibodies, but 13 (35%) antibody-positive cases already had more than one ICA before the age of 2 years and 7 (19%) showed reactivity to three islet cell antigens before age 5 years. The presence of multiple antibodies confers high risk for the future development of diabetes; three of six children who exhibited positive antibody responses to all four antibodies tested and another child with two positive antibodies developed clinical diabetes at the ages of 13, 21, and 27 months and 5 years. We conclude that loss of tolerance to beta-cell autoantigens and appearance of autoimmune phenomena occur very early in life in individuals with genetic susceptibility for IDDM. Screening programs to identify candidates for disease-prevention therapies can therefore be focused on this young age-group, in whom the disease process may be less advanced and who may therefore be best suited to such therapies.
Diabetes 1996 Jul
PMID:Perinatal autoimmunity in offspring of diabetic parents. The German Multicenter BABY-DIAB study: detection of humoral immune responses to islet antigens in early childhood. 866 50


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>