Effect of cyclosporine A treatment in vitro on pancreatic islet allograft rejection.
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Animals↗
Biomedical subjects
R Gomis
Publications and source records attributed to R Gomis.
High proinsulin levels in late PRE-IDDM stage.
AIM: To analyse the fasting proinsulin levels in first degree relatives of patients with insulin-dependent diabetes mellitus (IDDM) with different risk for developing the disease. PATIENTS AND METHODS: Non siblings first degree relatives, 33, of IDDM patients were separated into three groups with different risk for developing IDDM: Group 1, 14 first degree relatives (eight male/six female), aged from 18 to 57 years, normal first phase insulin release (FPIR) in the intravenous glucose tolerance test, negative ICA; Group 2, 11 first degree relatives (six male/five female), aged from 16 to 62 years, normal FPIR and ICA < 20 JDF U; Group 3, eight first degree (six male/two female), from 16 to 52 years, FPIR diminished and ICA > 20 JDF U. All patients had normal oral glucose tolerance test at the initiation of the study. We tested fasting proinsulin (PRO) and insulin (IRI) levels by radioimmunoassay (RIA) and the PRO/IRI ratio. RESULTS: Four first degree from the group 3 developed IDDM after 2-32 months. No differences were observed in-fasting PRO levels and PRO/IRI ratio between the groups. However, the PRO (21.7 +/- 5.8 pmol/l) and PRO/IRI ratio (0.29 +/- 0.10) levels of the subjects who developed IDDM were significantly higher (P < 0.05) than those values obtained in subjects who did not developed the disease. CONCLUSION: these data indicate that fasting PRO levels and the PRO/IRI ratio may be an additional marker in post-puberty first-degree relatives of IDDM patients with immunological and metabolic evidence of high risk for developing the disease.
Adolescent↗
Autoantibodies against mitochondrial glycerophosphate dehydrogenase in patients with IDDM.
The mitochondrial enzyme FAD-linked glycerophosphate dehydrogenase (mGDH) plays a key role in the recognition of D-glucose as a stimulus for insulin release from the pancreatic islet B-cell. This study reveals that autoantibodies against this enzyme are not uncommonly found in patients with insulin-dependent diabetes mellitus (IDDM) examined at the onset of the disease. Antibodies reacting with a recombinant mGDH fragment product were observed in the serum of four out of 15 type-1 diabetics, but in none of 15 control subjects. The serum of patients positive for the recombinant mGDH fragment also recognized native mGDH in a rat testis extract, provided that the enzymatic protein was first exposed to an anti-mGDH rabbit serum. Antibodies against mGDH were also found in four out 12 patients with autoimmune thyroiditis. These findings reveal that a mitochondrial enzyme, that represents an essential component of the islet B-cell glucose-sensing device, may act as an antigenic determinant in patients with IDDM or other autoimmune diseases.
Adolescent↗
Low mitochondrial glycerophosphate dehydrogenase activity in lymphocytes of women with gestational diabetes.
An abnormally low activity of mitochondrial FAD-linked glycerophosphate dehydrogenase (m-GDH), relative to the paired measurement of glutamate dehydrogenase, was found in CD3+ lymphocytes from 4 out of 14 mothers with gestational diabetes mellitus, but in none of 36 control mothers. The low m-GDH activity coincided with an abnormally high incidence of familial history for non-insulin-dependent diabetes. These findings are compatible with the view that an inherited or acquired defect of m-GDH may participate to the pathogenesis of beta-cell dysfunction in a subgroup of patients with gestational diabetes.
Adult↗
Nucleotide sequence of cDNA fragments coding for the FAD-,glycerophosphate- and calcium-binding domains of human islet mitochondrial glycerophosphate dehydrogenase.
The cDNA fragments coding for the FAD-, glycerophosphate- and calcium-binding domains of mitochondrial glycerophosphate dehydrogenase (mGDH) were synthetized using RNA extracted from freshly isolated pancreatic islets of a normal subject and two-non-insulin-dependent diabetic patients. Single strand conformation polymorphism analysis of the PCR products yielded the same mobility as control cDNA probes. Likewise, the nucleotide sequence and corresponding amino acid sequence were identical to the normal gene bank sequence. These findings argue against the presence, in pancreatic islets, of an mGDH isoform distinct from that previously characterized in extrapancreatic organs.
Aged↗
Beta-cell function abnormalities in islets from an adult subject with nesidioblastosis and autoantibodies against the islet cells.
Human islets from an adult subject with nesidioblastosis were isolated and used to perform in vitro studies. Isolated nesidioblastotic islets showed an increased basal rate of insulin secretion (nesidioblastotic islets, 81.3 +/- 6.4 vs. control islets, from cadaveric organ normal donors, 10.2 +/- 0.9 microU/islet/90 min) without any further release with increasing glucose concentration. In addition, islets isolated from the pancreas with nesidioblastosis contained more insulin than control islets, 1,547.0 +/- 128.7 vs. 935.0 +/- 51.7 microU/islet, and the levels of insulin mRNA were also higher than those measured in controls. Interestingly, the serum of the subject with nesidioblastosis contained autoantibodies that stained brightly and selectively a population of islet cells whose distribution coincided with that expected of alpha cells. In summary, pancreatic islets in nesidioblastosis display beta-cell functional abnormalities. Moreover, the finding of antibodies against islet cells is a common feature in the serum of nesidioblastotic subjects; nevertheless, their pathological significance warrants further investigation.
Adolescent↗
Glucose regulation of islet amyloid polypeptide gene expression in rat pancreatic islets.
Intracellular pathways by which glucose regulates islet amyloid polypeptide (IAPP) gene expression in pancreatic islets were studied. IAPP mRNA levels were threefold higher in islets cultured with 16.7 mM glucose compared with control (5.5 mM glucose). Mannose and amino acids but not 2-deoxyglucose or 6-deoxyglucose mimicked the effect of glucose. Mannoheptulose (a glycolysis inhibitor) and verapamil and diazoxide (which affect calcium signaling pathway) abolished the difference in islet IAPP mRNA content between high and low glucose. At low glucose, IAPP mRNA levels were increased 1.9-fold in islets treated with forskolin or dibutyryl adenosine 3',5'-cyclic monophosphate (DBcAMP) but not with 12-O-tetradecanoylphorbol 13-acetate. Insulin mRNA levels were 1.6-fold higher in islets cultured at high glucose than controls; glucose metabolism was required, whereas no effects of cAMP or diazoxide were observed. IAPP and insulin were cosecreted into the media. We conclude that glucose regulation of IAPP mRNA abundance requires intracellular metabolism of the hexose and that calcium may serve as a mediator of this effect; cAMP but not protein kinase C possibly participates in this regulation.
Amyloid↗
An automated fluorescent single-strand conformation polymorphism technique for screening mutations in the hepatocyte nuclear factor-1alpha gene (maturity-onset diabetes of the young).
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Autoanalysis↗
[Presence of markers predictive of type I pre-diabetes mellitus status in relatives of patients with type I diabetes mellitus].
BACKGROUND: The aim of this study was to analyze the predictive factors of IDDM in first degree relatives of IDDM patients. SUBJECTS AND METHODS: From 1992 to 1994, 1,053 first degree relatives were screened for measuring islet cell antibodies (ICA) by indirect immunofluorescence (iFl). In all ICA positive subjects, beta cell function was analyzed by intravenous glucose tolerance test (IVGTT) and other immunologic parameters were also studied: anti-insulin antibodies (IAA) by radiobinding and antibodies to glutamic acid decarboxylase (GADAb) by ELISA methods. RESULTS: ICA were found in 3.1% of the first degree relatives. IVGTT showed a significant decrease in acute first phase of insulin response to glucose (IRI 1 minute + 3 minute) in those with ICA > or = 20 JDF units. In patients with ICA > or = 20 JDF units, 20% were found to be positive for IAA and 40% were positive for GAdAb. Thirty-one percent (10/32) of ICA positive first degree relatives fulfilled prediabetes criteria. During follow-up, 40% (4/10) of these prediabetic patients developed IDDM. CONCLUSION: This study confirms the possibility of identifying among first degree relatives of IDDM patients the subgroup with high risk of developing IDDM thus allowing the initiation of therapy for preventing or delaying IDDM onset.
Adolescent↗
Pancreatic islet mitochondrial glycerophosphate dehydrogenase deficiency in two animal models of non-insulin-dependent diabetes mellitus.
Western blotting of pancreatic islet extracts from either hereditarily diabetic Goto-Kakizaki rats (GK rats) or animals injected with streptozotocin during the neonatal period (STZ rats) demonstrated a pronounced decrease of immunoreactive mitochondrial glycerophosphate dehydrogenase (m-GDH), when compared to results obtained in islets from control rats. By contrast, the islet glucokinase protein content was either unaffected (GK rats) or much less severely decreased than that of m-GDH (STZ rats). These findings indicate that the impaired activity of m-GDH previously documented in islet homogenates from diabetic rats coincides with a decreased content of this enzyme in the endocrine pancreas.
Animals↗
Immunodetection of mitochondrial glycerophosphate dehydrogenase (mGDH) by a polyclonal antibody raised against a recombinant mGDH fragment product.
The mitochondrial enzyme glycerophosphate dehydrogenase (mGDH) plays an essential role in the B-cell glucose-sensing device and its activity in islet homogenates is impaired in several animal models of type 2 diabetes. We have now developed a polyclonal antibody, raised against a recombinant mGDH fragment product, that could be used for the immunodetection of mGDH. Total RNA was isolated from rat pancreatic islets and used in the synthesis of cDNA. Specific primers were designed that corresponded to the FAD binding domain of mGDH. The PCR product was purified and cloned into an appropriate expression vector used for transformation of Escherichia coli cells. The fusion protein was extracted from the transformed cells, further purified, and used for immunization of rabbits. The antibody recognized a single band of 72 kDa in rat islets and testis. The recombinant mGDH product was also recognized as a single band with the expected 65-kDa reference. An ELISA procedure was designed for detection of antibodies against the recombinant mGDH fragment product. The availability of the mGDH antibody opens the way to a number of further applications such as immunocytochemis- try and mGDH quantification in biological material.
Animals↗
Follow-up study of the revascularization process of cryopreserved islets of Langerhans.
Cryopreservation of islets of Langerhans is a necessary procedure since human pancreatic islet transplantation has become a reality for the clinical treatment of Type I, insulin-dependent diabetes mellitus. Although successful cryopreservation of rodent and human islets is a well-established technique for islet storage after isolation and purification, little is known about the influence of the freeze-thaw procedure on the islets' potential to induce angiogenesis and revascularization, a major process necessary for the viability of grafted cells. In this study, the revascularization process of cryopreserved islets transplanted in the liver and in the renal subcapsular space of diabetic and nondiabetic rats is analyzed by a double indirect immunofluorescence technique. Frozen-thawed pancreatic islets were cooled slowly to -40 degrees C, stored at -196 degrees C, and thawed rapidly. Lewis rat were grafted with either Lewis (isografts) or Wistar (allografts) overnight-cultured and frozen-thawed islets obtained by collagenase digestion. Rats were killed different days after implantation, and the livers and kidneys bearing the grafted islets were snap-frozen and immunohistochemically stained with a double immunofluorescence technique using a rabbit anti-factor VIII antiserum (which labels endothelial cells) and a guinea pig anti-insulin antibody. Overnight-cultured islet grafts completed revascularization by Days 4-7 after transplantation, as shown by the detection of endothelial cells within and surrounding the islets. The identical staining pattern of revascularization was observed in islets frozen-thawed before transplantation. It is concluded that islet cryopreservation is a suitable technique for long-term storage prior to transplantation since it does not interfere with the neovascularization process of islet grafts.
Animals↗
FAD-glycerophosphate dehydrogenase activity in lymphocytes of type-2 diabetic patients and their relatives.
The activities of FAD-linked glycerophosphate dehydrogenase (m-GDH), glutamate dehydrogenase (GlDH), glutamate-pyruvate transaminase (GPT) and glutamate-oxalacetate transaminase (GOT) were measured in purified populations of CD3+ lymphocytes from 55 control subjects, 62 type-2 diabetics and 50 non-diabetic relatives of the latter patients. The activity of m-GDH was measured by both a radioisotopic procedure and colourimetric technique. As judged from these measurements and relative to the paired value for GlDH, the incidence of abnormally low m-GDH activity was significantly higher in type-2 diabetics than in control subjects. Moreover, the paired ratio in reaction velocity between the colourimetric and radioisotopic assay of m-GDH was abnormally high in patients with low m-GDH activity. Low m-GDH activity often coincided with increased GPT activity in plasma or high GPT/GOT ratio in lymphocytes. No obvious clustering of these anomalies was found in relatives of diabetic patients. These findings suggest that an inherited or acquired genomic defect of m-GDH in lymphocytes, and possibly in pancreatic B-cells, may participate to the pathogenesis of non-insulin-dependent diabetes mellitus.
Adult↗
Coenzyme Q10 and insulin secretion in vitro.
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Animals↗
Effects of insulin administration on beta-cell function in subjects at high risk for type I diabetes mellitus.
The aim of the study was to determine the appropriate dose of subcutaneous insulin to induce "beta-cell rest" without any hypoglycemic risk, as the first stop in the investigation of its potential effect in preventing or delaying clinical diabetes mellitus onset in high-risk subjects. Four subjects at high risk for type I diabetes mellitus (first-degree relatives, islet cell antibodies (ICA)-positive, and with diminished first-phase insulin secretion) were compared with four healthy individuals. After hospitalization, urinary C-peptide excretion (UCP) and 24-hour serum profiles for glucose were measured before and after administration of NPH insulin 0.1, 0.2, and 0.3 U x kg body weight per day subcutaneously in a single dose on 4 consecutive days. After insulin 0.1 U x kg body weight, a significant inhibition of endogenous insulin secretion was observed in high-risk subjects, but not in control subjects. There was no further inhibition when a higher insulin dose (0.2 and 0.3) was administered. A sustained beta-cell rest was obtained after 3, 6, and 12 months of treatment with 0.1 U x kg body weight per day as outpatient therapy in high-risk subjects. With this dose, no subject developed hypoglycemia (plasma glucose <50 mg/dL), whereas this adverse effect was detected after 0.2 and 0.3 U x kg body weight in both groups. In conclusion, our results indicate that administration of NPH insulin 0.1 U x kg bodyweight per day induces beta-cell rest without the undesirable effect of hypoglycemic episodes. This is a preliminary study to investigate the potential beneficial effect of insulin in preventing or delaying type I diabetes mellitus in subjects at high risk for the disease.
Adolescent↗
Antiphospholipid syndrome in a patient with type I diabetes presenting as retinal artery occlusion.
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Adult↗
Human insulin-induced lipoatrophy. Successful treatment using a jet-injection device.
OBJECTIVE: To evaluate the efficacy of the administration of insulin by a jet-injector device in stopping and reversing severe human insulin-induced lipoatrophy. CASE: We report a case of a woman with severe human insulin-induced lipoatrophy who has been treated exclusively with recombinant DNA human insulin since the onset of IDDM. RESULTS: The loss of subcutaneous tissue in the injection areas was demonstrated and measured by high-frequency ultrasound. Dermatologic exam demonstrated a severe reduction of fat tissue. After 8 months of administration of human insulin by a jet injector, there were no more new lesions of lipoatrophy and those affected areas were substantially ameliorated. CONCLUSIONS: Jet-injection devices might constitute a helpful method to treat those patients affected by severe human insulin-induced lipoatrophy.
Adult↗
[Retinopathy in patients with insulin-dependent diabetes mellitus of short duration].
To evaluate the role of metabolic control at the beginning of insulin-dependent diabetes mellitus (IDDM) in the development of diabetic retinopathy (DR) a cross-sectional study was performed with a retrospective analysis of 24 patients followed for at least seven years. The following parameters were investigated: 1) At IDDM diagnosis, age, sex, metabolic control (basal serum glucose, HbA1, cholesterol, triglycerides) and endogen insulin secretion (EIS). 2) At one year in the follow-up: EIS. 3) Since IDDM diagnosis and every 3-4 months: body mass index, dose and pattern of insulin administration and metabolic control. 4) At seven years in the follow-up: direct ophthalmoscopy, fluorescein angiography, microalbuminuria and blood pressure. In the seventh year of follow-up five patients (23.8%; 95% CI: 8.2%-47.2%) developed changes in fluorescein angiography secondary to IDDM. Compared with patients with normal fluorescein angiography their metabolic control was poorer (mean HbA1--seven years--: 11.7 +/- 0.5 versus 9.8 +/- 0.3%; p = 0.01); mean basal glycemia--seven years--: 214 +/- 13.3 versus 174 +/- 7.7 mg/dl; p = 0.03) and their systolic blood pressure (SBP) higher (124 +/- 5.5 versus 111 +/- 2.8 mmHg; p = 0.04). Logistic regression revealed that mean HbA1 values for seven years was the only independent risk factor significantly associated with the development of DR (p = 0.04). The conclusion is that in patients with IDDM of short duration, the development of DR is associated with a deficient glucose control and a higher SBP.
Adolescent↗