The impact of metformin treatment on adiponectin and resistin levels in women with polycystic ovary syndrome: a prospective clinical study.

Women with polycystic ovary syndrome (PCOS) are often characterized by adiposity and insulin resistance (IR). Recent studies in patients with obesity and diabetes mellitus type 2 (DMt2) indicate that adiponectin and resistin may play a role in the pathophysiology of IR. The aim of this study was to identify a possible correlation between the plasma levels of adiponectin and resistin and IR in patients with PCOS. Thirty-one women of reproductive age were enrolled in this prospective study after being diagnosed with PCOS and IR according to Rotterdam and American Diabetes Association (ADA) criteria, respectively. Every patient was treated with a daily dose of 1275 mg metformin for 6 months. Adiponectin, resistin, and the primary hormonal and metabolic parameters of the syndrome were evaluated at entry and endpoint of treatment. Adiponectin plasma levels were reduced after metformin treatment, but resistin levels were not significantly affected. Our study suggests that circulating levels of adiponectin should be evaluated with skepticism in patients with PCOS. The adipokine's role in the manifestation of IR in PCOS remains unclear and needs further investigation.

Age-dependent association of serum prolactin with glycaemia and insulin sensitivity in humans.

The dopamine agonist bromocriptine has been approved for the treatment of type 2 diabetes in the United States. Bromocriptine inhibits prolactin secretion, and patients with hyperprolactinaemia display impaired insulin sensitivity. We therefore hypothesized that low prolactin levels are associated with lower glycaemia and higher insulin sensitivity in healthy subjects. Prolactin levels were determined from fasting serum in participants without diabetes from the cross-sectional Tübingen family study for type 2 diabetes (m/f = 562/1,121, age = 40 ± 13 years, BMI = 30 ± 9 kg/m(2)). A 75 g oral glucose tolerance test was performed, and the area under the glucose curve (AUC(0-120)Glucose) and insulin sensitivity index were calculated. A subgroup (n = 494) underwent hyperinsulinaemic-euglycaemic clamp tests. Prolactin associated positively with insulin sensitivity (p = 0.001, adjusted for gender, age, and BMI). Age strongly interacted (p < 0.0001) with the effect of prolactin on insulin sensitivity, inverting the positive relationship to a negative one in younger participants. Glycated haemoglobin (HbA1c) and AUC(0-120)Glucose correlated negatively with prolactin, and an interaction with age was found as well. Higher prolactin levels are associated with improved insulin sensitivity and lower glucose in individuals without diabetes. This relationship turns to its opposite in younger persons. As prolactin is a proxy for the dopaminergic tone in the central nervous system, these associations may indicate an age-dependent influence of the brain on peripheral insulin sensitivity.

Do mast cells link obesity and asthma?

Asthma is a chronic inflammatory disease of the lungs. Both the number of cases and severity of asthma have been increasing without a clear explanation. Recent evidence suggests that obesity, which has also been increasing alarmingly, may worsen or precipitate asthma, but there is little evidence of how obesity may contribute to lung inflammation. We propose that mast cells are involved in both asthma and obesity by being the target and source of adipocytokines, 'alarmins' such as interleukin-9 (IL-9) and interleukin-33 (IL-33), and stress molecules including corticotropin-releasing hormone (CRH) and neurotensin (NT), secreted in response to the metabolic burden. In particular, CRH and NT have synergistic effects on mast cell secretion of vascular endothelial growth factor (VEGF). IL-33 augments VEGF release induced by substance P (SP) and tumor necrosis factor (TNF) release induced by NT. Both IL-9 and IL-33 also promote lung mast cell infiltration and augment allergic inflammation. These molecules are also expressed in human mast cells leading to autocrine effects. Obese patients are also less sensitive to glucocorticoids and bronchodilators. Development of effective mast cell inhibitors may be a novel approach for the management of both asthma and obesity. Certain flavonoid combinations may be a promising new treatment approach.

Insulin resistant phenotype of polycystic ovary syndrome does not seem to be caused by variation in FTO.

Genetic variation in the FTO gene is associated with increased body weight and reduced insulin sensitivity. We investigated whether genetic variation in FTO is associated with polycystic ovary syndrome (PCOS), a condition also characterized by insulin resistance. Furthermore, we tested whether insulin resistance is specifically associated with genetic variation in FTO in women with PCOS. Sixty-two nondiabetic patients with PCOS defined by the Rotterdam criteria were compared to BMI and age-matched women. Each PCOS case was matched to 2 controls. All participants underwent an oral glucose tolerance test and were genotyped for the single nucleotide polymorphism rs8050136 in the FTO gene. There was no difference in the frequency of FTO genotypes between the PCOS and the non-PCOS groups. In non-PCOS participants, genetic variation in FTO is associated with insulin sensitivity (p=0.03). This association remained significant after adjustment for age and/or BMI (p<= 0.03). In subjects with PCOS, however, FTO did not associate with insulin sensitivity (p=0.67). Genetic variation in FTO does not have an impact on insulin sensitivity in women with PCOS and is therefore not involved in the pathogenesis of the insulin resistant phenotype seen in patients with PCOS.

Effect of hyperthyroidism on clearance and secretion of glucagon in man.

OBJECTIVE: Glucagon has been proposed to contribute to the increased glucose production found in hyperthyroidism. However, fasting plasma glucagon levels are not increased in hyperthyroidism suggesting that the activity of the α-cell is normal. Nevertheless, an increase in the clearance rate of glucagon may mask increased glucagon secretion. This study was designed to examine the effects of hyperthyroidism on the kinetics of glucagon. DESIGN AND METHODS: A primed-continuous infusion of glucagon was administered to 9 euthyroid and 9 hyperthyroid subjects at 3 sequential rates (1,200, 3,000 and 6,000 pg/kg/min, each given for 2 h). Arterialized blood was drawn at 15-30 min intervals for determination of glucagon. RESULTS: Fasting plasma glucagon levels were comparable in euthyroids (195±8 pg/ml) and hyperthyroids (231±16 pg/ml). During infusions (1,200, 3,000 and 6,000 pg/kg/min), plasma glucagon increased to 387±19, 624±44 and 977±51 pg/ml in euthyroids and to 348±23, 597±42 and 938±56 pg/ml in hyperthyroids respectively. At these infusion rates, metabolic clearance of glucagon (ml/kg/min) was 6.6±0.5, 7.4±0.6 and 7.9±0.5 in euthyroids and 12.6±2, 8.9±1 and 8.8±0.6 in hyperthyroids, respectively. Metabolic clearance of glucagon differed between hyperthyroids and euthyroids at 1 200 pg/kg/min infusion rate (p=0.001). The basal delivery rate of glucagon (ng/kg/min) was 1.3±0.1 in euthyroids and 2.9±0.6 in hyperthyroids (p=0.0005). CONCLUSIONS: In hyperthyroidism, the secretion and metabolic clearance rates of glucagon are increased. These effects may explain the changes in plasma glucagon levels observed in hyperthyroidism and support the important role of glucagon in increasing endogenous glucose production in this condition.

Can Internet surveys help us understanding allergic disorders? - results from a large survey in urticaria in Greece.

BACKGROUND: Urticaria is often underdiagnosed and/or undertreated. We have conducted an Internet-based study to record epidemiological and clinical features as well as therapeutic interventions for urticaria in a large sample of patients in Greece. METHODS: A standard anonymous questionnaire was posted for a 3-month period on 'http://www.in.gr', a Greek popular Internet portal. Each individual participated only once. Participants were screened for the presence or history of urticaria by two key questions and were then asked to provide information on symptomatology and management. RESULTS: A total of 12 396 subjects voluntarily responded to the survey, of which 8440 (5136 females) who reported to have or had urticaria, were finally analysed. A total of 4780 (56.6%) had experienced weals only, 507 (6.0%) angio-oedema only and 3018 (35.8%) both. Weals and angio-oedema were found to be more common in women; 2761(57.8%) and 277(54.6%), respectively. Age of onset significantly correlated with disease duration; a 1% higher possibility of longer duration of urticaria exists (more than 6 weeks compared with less than 6 weeks) for each additional year of age of onset after controlling for gender. Patients with chronic urticaria had increased mean age compared with those reporting the acute form (35.04 vs. 33.88 years, P < 0.001). Dermatologists were the most frequently visited specialists and the most common treatments were antihistamines and topical preparations. The self-reported eliciting factors of urticaria were as follows: physical stimuli (approximately 25%), psychological distress (17.2%), direct contact to metals or chemicals (14.5%), foods and drugs (10%), whereas a third of the participants could not identify any trigger. CONCLUSIONS: Internet surveys can be a useful tool for screening the general population for common allergic disorders, such as urticaria.

Correlation between intracellular interferon-gamma (IFN-gamma) production by CD4+ and CD8+ lymphocytes and IFN-gamma gene polymorphism in patients with type 2 diabetes mellitus and latent autoimmune diabetes of adults (LADA).

IFN-gamma is considered to be involved in the pathogenesis of diabetes mellitus. In this study, the presence of T/A mutation at position -874 in IFN-gamma gene was assessed in patients with latent autoimmune diabetes of adults (LADA), in patients with type 2 diabetes and in healthy individuals. Subsequently, an attempt was made to correlate the presence of this mutation with the ability of CD4+ or CD8+ lymphocytes from these individuals to release IFN-gamma following mitogenic stimulation. There were no significant differences in the distribution of genotypes and haplotypes in the three study groups. However, the frequency of the low IFN-gamma production allele (IFN-gamma 874( *)A) was significantly higher in type 2 diabetics compared to controls. CD4+ and CD8+ cells obtained from type 2 diabetics released significantly lower amounts of IFN-gamma in the intracellular space, compared to those released by cells obtained from LADA patients and healthy volunteers. Furthermore, even CD4+ and CD8+ from type 2 diabetics bearing the TT genotype (high producers) released significantly lower amounts of IFN-gamma than LADA patients carrying the same genotype, probably due to the activity of molecules directly or indirectly inhibiting IFN-gamma production. The results of this study indicate that IFN-gamma may contribute to the development of type 2 diabetes, based on a combination of molecular and immunological observations.

TNF-alpha, TGF-beta1, IL-10, IL-6, gene polymorphisms in latent autoimmune diabetes of adults (LADA) and type 2 diabetes mellitus.

Abundant evidence suggests that cytokines involve in the pathogenesis of latent autoimmune diabetes of adults (LADA). This is a slowly progressive form of type 1 diabetes, which is initially diagnosed as type 2 diabetes. In this study, healthy individuals LADA and type 2 diabetic patients were genotyped for IL-6-174G/C, TNF-alpha-308A/G, TGF-beta1-codon10T/C, TGF-beta1-codon25G/C, IL-10-1082A/G, IL-10-819T/C, IL-10-592A/C gene polymorphisms, by sequence-specific-primer polymerase chain reaction methodology. A significant difference in the frequencies of -1082A/G IL-10 alleles was observed, with the -1082*A allele (known to be associated with low IL-10 production), predominating in LADA diabetics than type 2 diabetics (p=0.036). No significant differences of genotypes, phenotypes, or haplotype frequencies in the remaining cytokine polymorphisms were observed. Analysis of allele combinations revealed a significant involvement of the low and high in vitro production IL-10 alleles in the development of LADA and type 2 diabetes, respectively. These results suggest that the G/A mutation at position -1082 of IL-10 promoter gene region might be one of the factors participating to the pathogenesis of LADA diabetes and that identification of cytokine gene polymorphisms might contribute to the characterization of the different types of diabetes mellitus.

Intracellular IFN-gamma production and IL-12 serum levels in latent autoimmune diabetes of adults (LADA) and in type 2 diabetes.

Th1 cytokines, such as interleukin-2 (IL-2) and interferon-gamma (IFN-gamma), and Th1-inducing cytokines, such as IL-12, are involved in the pathogenesis of various organ-specific autoimmune diseases, including autoimmune diabetes. In this study, we investigated intracellular IFN-gamma release by T lymphocytes and IL-12 serum levels in 48 type 2 and 36 latent autoimmune diabetes of adults (LADA) diabetics and 25 control subjects in an attempt to evaluate their role in the pathogenesis of these clinical entities. Ionomycin (ION) and phorbol-12-myristate-13-acetate (PMA)-activated peripheral blood mononuclear cells (PBMCs) were stained with anti-CD4-FITC or anti-CD8-FITC and anti-IFN-gamma phycoerythrin (PE) monoclonal antibodies (mAbs) and analyzed by flow cytometry. IL-12 serum levels were determined by enzyme-linked immunosorbent assay (ELISA). In all study groups, IFN-gamma content of CD4(+) and CD8(+) lymphocytes was significantly upregulated by stimulation. Furthermore, it was observed that CD4(+) and CD8(+) lymphocytes from type 2 diabetics produced significantly lower levels of IFN-gamma compared with LADA patients and controls. However, the percentages of CD4(+)/IFN-gamma(+) and CD8(+)/IFN-gamma(+) cells from type 2 diabetics were significantly higher compared with controls. The flow cytometric picture of intracellular IFN-gamma release in LADA patients did not differ from that observed in controls. However, IL-12 serum levels in type 2 and LADA diabetics were lower than in controls. Because Th1 cytokines have been associated with the pathogenesis of autoimmune diabetes, these results preclude Th1 involvement in the autoimmune phenomena observed in LADA patients. In contrast, the low IFN-gamma levels observed in type 2 diabetics in combination with the low IL-12 serum levels might be a contributing factor in the frequently observed chronic complications in these patients.

Flow cytometric detection of intracellular IL-12 release: in vitro effect of widely used immunosuppressants.

Interleukin 12 (IL-12) is a potent regulator of the Th1/Th2 pathway, enhancing alloantigen-specific immune functions. In the present study, we developed a flow cytometric assay detecting intracellular IL-12 production by human CD14+ monocytes in order to assess the in vitro effects of widely used immunosuppressants, such as cyclosporine (CsA), sirolimus (SRL) and dexamethasone (DXM). For the purpose of the study, a two-step activation procedure was developed involving the preactivation of peripheral blood mononuclear cells (PBMC) with interferon-gamma (IFN-gamma) and reactivation with IFN-gamma and lipopolysaccharide (LPS). All immunosuppressive agents were added at the initiation of the preactivation or the reactivation step. Following this activation protocol, a fourfold to fivefold up-regulation of the percentage of CD14+/IL-12+ cells and of the mean fluorescence intensity was observed. CsA did not significantly affect the intracellular IL-12 release by CD14+ cells, independent of the time point of the addition. SRL exerted an up-regulatory effect when added at the initiation of the IFN-gamma pre-incubation, and this was manifested as a significant increase in the percentage of CD14+/IL-12+ cells. In contrast, DXM effectively repressed both the percentage and the fluorescence intensity of IL-12-producing CD14+ cells when added at the initiation of the reactivation step. Since only the steroid preparation was shown to down-regulate the intracellular release of IL-12, it is tempting to assume that steroid addition in immunosuppressive schemes is beneficial for the suppression of Th1-inducing cytokine production, as well as for the compensation of possible up-regulation induced by other immunosuppressive agents administered concurrently.

Modern concepts for the prediction of type 1 diabetes.

Type 1 diabetes results from the destruction of the insulin-producing beta cells of the pancreas. The disease process is thought to be initiated by a complex interaction between genetic and environmental factors leading to a cellular and humoral autoimmune response against beta cell specific components. Over the past decade there has been important progress in identification of several diabetes specific autoantigens. The availability of recombinant antigens, most notably the enzyme glutamic acid decarboxylase (GAD) and the tyrosine phosphatase-like molecule IA-2, made it possible to develop simple, sensitive and specific radioimmunoassays for the detection of autoantibodies on a large scale. It has been shown that the combination of GAD antibodies (GADA) and IA-2 antibodies (IA-2-A) with insulin autoantibodies (IAA) can replace the conventional ICA test. This considerably facilitates screening programmes. Prospective studies in subjects with and without family history of type 1 diabetes conclusively demonstrate that the risk for type 1 diabetes is strongly correlated with the number of positive antibodies. The 5-10-years risk for type 1 diabetes varies from 0-1% in individuals with only one positive antibodies to 62-100% in subjects who were positive for three or more antibodies. Despite the identification of novel genetic markers associated with type 1 diabetes, the major histocompatibility complex, namely HLA-DQ alleles, still represents the strongest genetic risk factor. The analysis of HLA-DQ alleles may be important to discriminate between subjects at high or intermediate risk from antibody positive individuals carrying protective haplotypes. Assessment of the metabolic state using the first phase insulin response to intravenous glucose may provide additional information to predict rapid progression to diabetes. Screening for multiple antibodies is the most specific and sensitive strategy for identifying subject at risk for type 1 diabetes. Second-line genotyping or analysis of the first phase insulin response can serve as useful tool to improve the prediction of type 1 diabetes. The value of additional markers such as isotype specific autoantibodies or T-helper cells subsets measured by ELISPOT assays or FACS remains to be shown.

Islet transplantation: present clinical situation and future aspects.

Beta-cell replacement either by pancreatic organ or islet cell transplantation is the only treatment to achieve an insulin-independent, normoglycemic state and to avoid hypoglycemic episodes in patients with type 1 diabetes mellitus. This article will review the state-of-the-art in clinical islet cell transplantation at the dawn of the new millennium and will provide an outlook on the basis of extended personal experience.

Comparative analysis of organ-specific autoantibodies and celiac disease--associated antibodies in type 1 diabetic patients, their first-degree relatives, and healthy control subjects.

OBJECTIVE: In type 1 diabetes the coexistence with other endocrine diseases and organ-specific autoantibodies has been frequently reported leading to the concept of autoimmune polyendocrine syndrome (APS). In addition, an association of type 1 diabetes with celiac disease has been described. These disorders share a similar genetic background, and first-degree relatives of type 1 diabetic patients may also be affected significantly. Screening for specific antibodies allows early diagnosis of these disorders. RESEARCH DESIGN AND METHODS: In the present cross-sectional study, we analyzed sera from 197 recent-onset type 1 diabetic patients at the time of diagnosis, 882 first-degree relatives, and sera of 150 healthy control subjects for prevalence and co-occurence of the following antibodies (method): insulin autoantibodies (radioimmunoassay); GAD and IA-2 antibodies (radioligand assay); islet cell antibody, anti-adrenal cortex antibodies, and anti-gastric parietal cell antibodies (indirect immunofluorescence); anti-thyroglobulin and anti-thyroid peroxidase antibodies; and gliadin IgG/A and tissue-transglutaminase IgA (enzyme-linked immunosorbent assay). RESULTS: The overall frequency of gastric patietal cell antibodies and adrenal antibodies did not differ significantly among groups. In contrast, type 1 diabetes-associated antibodies and thyroid antibodies were significantly more frequent both in recent-onset type 1 diabetic patients and in the group of first-degree relatives (P < 0.05). The prevalence of gliadin IgG/IgA and transglutaminase IgA was significantly higher in the group of recent-onset type 1 diabetic patients (P < 0.05), but the difference between first-degree relatives and control subjects did not reach statistical significance. Focusing on the coexistence of antibodies, the group of recentonset type 1 diabetic patients presented with 27.4% of the subjects testing antibody-positive-specific for two or more of the envisaged disorders (i.e., type 1 diabetes, autoimmune thyroiditis, and celiac disease) compared with 3.1% in the group of first-degree relatives and 0 of 150 in the control population (P < 0.05). CONCLUSIONS: We conclude that, in an active case-finding strategy, recent-onset type 1 diabetic patients should be routinely screened at least for concomitant autoimmune thyroid disease and additionally for celiac disease. Screening in their first-degree relatives should include at a minimum the search for thyroid autoimmunity in addition to screening for pre-type 1 diabetes.

The combination of antibodies to GAD-65 and IA-2ic can replace the islet-cell antibody assay to identify subjects at risk of type 1 diabetes mellitus.

First-degree relatives of type 1 diabetic patients are at increased risk of developing diabetes and, until recently, islet cell antibodies (ICA) have represented the major risk marker used for identification of individuals at increased risk for subsequent progression to diabetes. In order to determine the value of antibodies to GAD-65 and IA-2ic to identify individuals at high risk for type 1 diabetes mellitus, we measured both autoantibodies and ICA in 1436 first-degree relatives of patients with type 1 diabetes. In addition, the sera were analyzed for thyroid, adrenal and gastric-parietal cell autoantibodies as markers for possible polyendocrine involvement. GAD-65 Abs were found in 135 out of 1436 (9.4%) first-degree relatives and in 57 of 98 (58.2%) ICA-positive subjects. IA-2ic were detected in 52 of 1436 (3.6%) first-degree relatives and in 44 of 98 (44.8%) ICA-positive relatives. IA-2ic and/or GAD-65 were detected in 73 of 98 (74.5%) ICA-positive relatives. Interestingly, antibodies to GAD-65 and/or IA-2ic were present in 91.2% of individuals with more than 20JDF-units. Anti-IA-2ic and GAD-65 were positively correlated with high levels of ICA. Anti-IA-2ic and GAD-65 were found in 19% and 48.5% of subjects with ICA levels of 5-20JDF-u but in 68.8% and 76.5% of individuals with ICA of 40JDF-u or more, respectively (p < 0.001), compared to subjects with ICA levels less than 5 JDF-u. When autoantibody frequencies among the relatives were analyzed according to relationship to the proband, the offspring and siblings had a higher frequency of ICA and IA-2ic (p<0.05) than the subgroup of parents. A significant association was observed between IA-2ic and thyroid antibodies. In addition, higher levels of IA-2ic were found in relatives with positive TPO antibodies (p < 0.001); this correlation was particularly strong in offspring and siblings (p < 0.01). Determination of GAD-65 and IA-2ic antibodies may be considered as an alternative to primary ICA-screening, enabling the screening of large populations.

The Giessen-Bad Oeynhausen family study: improved prediction of type I diabetes in a low incidence population of relatives using combinations of islet autoantibodies in a dual step model.

To determine the value of a combined antibody screening for prediction of type I diabetes in a low incidence cohort, we prospectively studied 882 first-degree relatives (485 parents, 382 siblings and 15 offsprings) for up to 11 years who were not preselected for islet cell antibody (ICA) status. During the observation period, 16 individuals developed diabetes. The first serum sample obtained at study entry was analyzed for ICA and antibodies to insulin (IAA), glutamic acid decarboxylase (GADA) and anti-IA-2ic. A multivariate analysis, according to the Cox proportional hazard model considering the joint effects of all baseline variables, selected the four antibodies and the specific family history as significant risk confounding factors (p < 0.05). Further analysis by Kaplan-Meier Life-table methods confirmed a significantly increasing risk of diabetes with the number of autoantibodies present (p < 0.001). In accordance with the Cox model, relatives with more than one affected family member (a multiplex pedigree) and siblings and offsprings vs. parents were at increased risk of IDDM (p < 0.05). In addition to technical problems, a screening strategy based on initial ICA testing has the potential of missing ICA negative subjects among future cases of type I diabetes (19% were ICA negative in the present study) and we therefore set out to evaluate an alternative approach using a dual step strategy with a combination of GADA and anti-IA-2ic for initial screening followed by retesting of positive individuals for ICA and IAA. The combination of GADA and anti-IA-2ic for primary screening (step 1) proved to be more sensitive, identifying 94% of future cases of type I diabetes compared to 81% using ICA as initial test and this antibody combination identified 93% of those individuals with ICA of 20 JDF or more. Retesting of positive individuals for ICA and IAA (step 2) significantly improved the positive predictive value confering a risk of diabetes for siblings and offsprings with more than 2 antibodies within 5 years of 67% (95%CI: 39-90). We conclude that the prognosis of contracting IDDM in relatives is strongly related to the number of autoantibodies present, but the family history should be additionally considered for individual risk assessment. The proposed screening strategy could overcome the inherent problems of the ICA and IAA assays for large-scale screening. In the present study it allows 5-year risk estimates of up to 67% identifying 94% of future cases of type I diabetes.

Comparative effects of glimepiride and glibenclamide on blood glucose, C-peptide and insulin concentrations in the fasting and postprandial state in normal man.

A single-center, randomised, placebo- controlled, cross-over study was conducted to characterize the new sulfonylurea glimepiride and to compare its profile of action with the second generation sulfonylurea glibenclamide. The total duration of each experiment was 5 hours. At zero time an i.v. injection of 2 and 4 mg glimepiride, 1 mg glibenclamide or placebo was given i.v. to 24 healthy volunteers. Blood samples were collected for three hours after the injection (0-3 hours, preprandial experiment). At 3 hours, a standard mixed meal was given (20%, of a 30 Kcal/Kg Body Weight diet) and blood samples were collected for 2 more hours (postprandial experiment). Pre-prandially (0-3 hrs) blood glucose (expressed as the area under the curve divided by the time) was significantly lower (p < 0.0001) after the administration of 2 and 4 mg glimepiride (3.8 +/- 0.22 and 3.5 +/- 0.3 mM respectively) compared to placebo (4.63 +/- 0.31 mM), but not compared to glibenclamide. Insulin and C-peptide were not different after glimepiride or glibenclamide. Both glimepiride and glibenclamide had similar effects on insulin secretion. Post-prandially (3-5 hrs) blood glucose was significantly higher after glibenclamide (6.54 +/- 0.8 mM) (p < 0.0001) than after 2 mg glimepiride (5.75 +/- 0.5 mM). Despite this C-peptide was significantly higher (p < 0.002) glibenclamide (5.7 +/- 1.5 ng/ml) compared to glimepiride (5.1 +/- 1.3 ng/ml); the trend was the same for insulin but the results were not significantly different (p = 0.06) In conclusion, in the fasting state, glimepiride and glibenclamide had similar effects on the changes in blood glucose levels after i.v. administration. After the meal, less pronounced hyperglycemia and lower insulin and C-peptide levels following glimepiride (2 mg) suggests either that glimepiride induces insulin secretion through a pathway which is different from that of glibenclamide or that glimepiride facilitates insulin action through extrapancreatic effects.

Glutamic acid decarboxylase antibodies are more frequent than islet cell antibodies in islet transplanted IDDM patients and persist or occur despite immunosuppression.

Pancreatic islet grafts transplanted into patients with autoimmune diabetes are potentially threatened by two immune responses, allograft rejection and the recurrence of autoimmune insulitis. In the present study we investigated the humoral autoimmune response directed to islet autoantigens by studying islet cell antibodies and glutamic acid decarboxylase (GAD 65) antibodies in twenty-one insulin-dependent diabetes-mellitus (IDDM) patients undergoing intraportal islet allotransplantation. Islet transplantation was performed according to the following recipient categories: Islet after kidney transplantation (n=10), simultaneous islet and kidney transplantation (n=6) and islet transplant alone (n=5). GAD 65 antibodies were detected in a radioligand GAD 65 antibody assay using recombinant, in vitro translated, human 35S-methionin labelled GAD 65 as tracer. Islet cell antibodies were determined by indirect immunofluorescence technique on human pancreas. In six out of twenty-one patients we observed GAD 65 antibodies before islet transplantation and the GAD 65 antibodies persisted despite immunosuppression. In contrast only two subjects were concordantly islet cell antibody positive and the titre decreased post transplantation. In addition we observed occurrence of GAD 65 antibodies in five subjects that were shown to be antibody negative before islet transplantation with three of them subsequently becoming positive for islet cell antibodies. The remaining ten patients were GAD 65 antibody and islet cell antibody negative before islet transplantation and remained negative thereafter. Interestingly none of the patients was exclusively positive for islet cell antibodies without being positive for GAD 65 antibodies. In summary we have demonstrated in twenty-one islet grafted individuals that humoral autoimmunity to islet antigens can persist or occur despite immunosuppression. Islet cell antibodies appear to be less frequent (5 out of 21, 23%) compared to GAD 65 antibodies (11 out of 21, 52%) suggesting that they are more affected by immunosuppressive therapy. We conclude that GAD 65 antibodies are a useful tool to further evaluate a possible link between persistent autoimmunity and early or late graft failure after islet transplantation.

Persistent GAD 65 antibodies in longstanding IDDM are not associated with residual beta-cell function, neuropathy or HLA-DR status.

Persistent humoral autoimmunity to the enzyme glutamic acid decarboxylase (GAD) has been described in a substantial proportion of patients with insulin-dependent diabetes mellitus (IDDM) of long duration. The source of the stimulus for this autoimmune reactivity is still unknown. Because the GAD 65 isoform is mainly expressed in pancreatic beta-cells and in the nervous system we investigated in the present study of the largest number of well characterized patients with longstanding IDDM (n = 105; median duration: 21 years; range: 10-46 years) the presence of autoantibodies to GAD 65 and their relationship to a residual C-peptide response or peripheral and autonomic neuropathy. Additionally we studied the HLA-DR status relative to GAD 65 antibodies in 86 out of the 105 individuals. One hundred healthy control subjects and 100 recent onset IDDM patients were also studied for GAD 65 antibodies. GAD 65 antibodies were detected in a radioligand-binding-assay with recombinant human GAD 65 and were present in 32% of the long-term diabetic patients, 82% of the recent onset IDDM patients and in 3% of the healthy control subjects. A preserved C-peptide response to i.v. glucagon (Hendriksen criteria) was observed in 23% of the long-term IDDM patients. Autonomic neuropathy and peripheral neuropathy was identified using criteria based on both symptoms and formal testing giving a frequency of 67% vs 79%. The HLA specific DR 4/X was observed in 47% and HLA-DR 3/X in 22% of the long-term IDDM patients. Patients who were heterozygous for DR3/DR4 were found in 23% of the cases. GAD 65 antibodies were significantly less frequent in the long-term IDDM patients compared to recent onset IDDM (p < 0.001), and diabetes duration showed a significant negative correlation with GAD 65 antibody index levels (r = 0.22, p < 0.01). Interestingly, GAD 65 antibodies were not significantly correlated either with residual beta-cell function or neuropathy and no particular HLA-DR status was associated with persistent GAD 65 antibodies. In conclusion neither residual beta-cell function nor diabetic neuropathy or a certain HLA-DR specificity are exclusively associated with persistent autoimmunity directed to GAD 65 in longstanding IDDM. The stimulus for the persistent humoral immune response and its significance for the disease process and its complications remain to be established.

GAD 65 antibody but not ICA positivity in adult-onset diabetic patients is associated with early progression to clinical insulin dependency.

Correct classification of diabetic patients in adulthood at the time of diagnosis is often difficult. Some may be initially diagnosed as having non-insulin-dependent diabetes mellitus and be treated with diet and/or oral hypoglycaemic agents (OHA) but later require insulin treatment. Islet cell antibodies and antibodies to GAD 65 have been associated with the development of insulin deficiency in this group of patients. In the present study, 150 patients with the initial diagnosis of type 2 diabetes mellitus in adulthood (30-60 years) were seen regularly over a period of 5 years in our diabetes outpatient clinic. Though treatment was started with diet or diet plus OHA, insulin therapy had to be introduced in a subset of patients. In all cases, serum obtained at the time of the initial diagnosis was analysed for islet cell antibodies and GAD 65 antibodies, as well as for thyroid and adrenal autoantibodies as possible markers for polyendocrine involvement. Islet cell antibody status, body mass index and the presence of thyroid and adrenal autoantibodies showed no significant correlation to subsequent insulin requirement (< 2 years after diagnosis). In contrast, GAD 65 antibodies were significantly associated with the occurrence of clinical insulin dependency less than 2 years after the initial diagnosis (P < 0.01), thus identifying a substantial proportion of patients requiring insulin therapy within the first 2 years after the diagnosis of type 2 diabetes. Determination of GAD 65 antibodies in patients with late-onset diabetes may contribute to their correct classification and adequate treatment.

Effects of prolonged administration of two new alpha-glucosidase inhibitors on blood glucose control, insulin requirements and breath hydrogen excretion in patients with insulin-dependent diabetes mellitus.

Alpha-glucosidase inhibitors delay carbohydrate absorption. In order to study the effects of two new alpha-glucosidase inhibitors with long (BAYo1248) and short (BAYm1099) duration of action on glycaemic control, seventeen insulin-dependent diabetics were connected to the Biostator for 24 h and postprandial hyperglycaemia, insulin requirements and breath H2 concentrations were assessed under three conditions: (a) before administration of any alpha-glucosidase inhibitor (control experiments), (b) after administration of BAYo1248 (40 mg before breakfast, nine patients) or BAYm1099 (100 mg before breakfast and dinner, eight patients) for 1 month, (c) after 1-month administration of placebo (double-blind crossover study). All patients were on standard diets (30 kcal kg-1, 45% carbohydrate, 35% fat, 20% protein). BAYo1248 reduced postprandial hyperglycaemia and insulin requirements (vs. values in control and placebo experiments) after breakfast (124 +/- 8 vs. 159 +/- 8 and 158 +/- 8 mg dl-1, 16 +/- 2 vs. 24 +/- 4 and 23 +/- 3 units, P less than 0.01) and lunch (138 +/- 7 vs. 155 +/- 11 and 162 +/- 13 mg dl-1, 19 +/- 3 vs. 24 +/- 3 and 23 +/- 3 units, P less than 0.01) whereas BAYm1099 reduced postprandial hyperglycaemia and insulin requirements after breakfast (127 +/- 4 vs. 167 +/- 12 and 159 +/- 6 mg dl-1, 15 +/- 3 vs. 24 +/- 4 and 21 +/- 3 units, P less than 0.02) and dinner (128 +/- 4 vs. 169 +/- 7 and 157 +/- 10 mg dl-1, 19 +/- 2 vs. 28 +/- 3 and 25 +/- 2 units, P less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)