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R Gomis

Publications and source records attributed to R Gomis.

At least 37 records · Page 2Linked to original sources
PubMed2002

Polymorphism in intron 2 of islet amyloid polypeptide gene is associated with lower low-density lipoprotein cholesterol in nondiabetic subjects and in type 2 diabetic patients.

The aim of this study was to investigate the presence of mutations in the islet amyloid polypeptide (IAPP) gene in a Spanish population with type 2 diabetes and gestational diabetes mellitus (GDM). Using polymerase chain reaction single-stranded conformation polymorphism, we examined the coding region and the 5'-untranslated region (UTR) of the IAPP gene in 177 unrelated type 2 diabetic patients, 110 healthy control subjects, 38 women with GDM, and 38 gestational control subjects. Mutations were confirmed by DNA sequencing. A heterozygous C-to-A nucleotide substitution at +79 bp in intron 2 of the IAPP gene was detected. The frequencies of the +79-bp polymorphism (A allele) were 6.8% in type 2 diabetic patients, 7.7% in nondiabetic control subjects, 11.8% in women with GDM, and 9.2% in gestational control subjects. No AA genotypes were detected. Nondiabetic subjects and patients with type 2 diabetes bearing the CA genotype had lower low-density lipoprotein (LDL) cholesterol levels than subjects bearing wild genotype. Multivariate logistic regression analysis showed an independent association (p < 0.001; odds ratio: 0.33; 95% confidence interval: 0.17-0.63). We did not detect any sequence variant within exons 1 or 2. One diabetic patient was heterozygous for a silent mutation at codon 31 of exon 3 (Asn31 AAC --> AAT). Our findings indicate that the presence of the +79-bp polymorphism of the IAPP gene in nondiabetic subjects and in patients with type 2 diabetes is associated with lower levels of LDL cholesterol. Furthermore, abnormalities of the coding regions or the 5'-UTR of the IAPP gene are not associated with type 2 diabetes or GDM in the Spanish population.

Aged↗
PubMed2001

[Effect of irbesartan on the development of diabetic nephropathy in patients with type 2 diabetes].

INTRODUCTION: Microalbuminuria and hypertension are risk factors for the development of diabetic nephropathy. Blockade of the renin-angiotensin system reduces progression to diabetic nephropathy in type 1 diabetic patients, whereas similar data are lacking for hypertensive type 2 diabetic subjects. We evaluated the renoprotective effect of an angiotensin II receptor antagonist, irbesartan, in hypertensive type 2 diabetic patients with microalbuminuria. MATERIAL AND METHODS: Five hundred and ninety hypertensive type 2 diabetic patients with microalbuminuria were enrolled in this multinational, randomised, double-blind, placebo-controlled study of irbesartan 150 mg/daily or 300 mg/daily or matching placebo for two years. The primary outcome was time to progression to diabetic nephropathy, defined as a persistent overnight albuminuria > 200 micrograms/min and at least a 30 per cent increase from baseline. RESULTS: Baseline characteristics in the three groups were similar. Ten patients (5.2 per cent) receiving irbesartan 300 mg and 19 patients (9.7 per cent) receiving irbesartan 150 mg daily reached the primary end point, as compared to 30 (14.9 per cent) patients on placebo (hazard ratio 0.30 [95 per cent confidence interval 0.14 to 0.61], p < 0.001 and 0.61 [95 per cent confidence interval 0.34 to 1.08] p = 0.08), respectively). The average blood pressure throughout the study was 144/83, 143/83, and 141/81 mmHg in the placebo, irbesartan 150 mg and 300 mg group, respectively (p = 0.004 for systolic blood pressure). Serious adverse events were less frequent in the patients treated with irbesartan (p = 0.02). DISCUSSIONS: Irbesartan is renoprotective independently of its blood pressure lowering effect in type 2 diabetic subjects with microalbuminuria. It is safe and well tolerated.

Adult↗
PubMed2001

The effect of irbesartan on the development of diabetic nephropathy in patients with type 2 diabetes.

BACKGROUND: Microalbuminuria and hypertension are risk factors for diabetic nephropathy. Blockade of the renin-angiotensin system slows the progression to diabetic nephropathy in patients with type 1 diabetes, but similar data are lacking for hypertensive patients with type 2 diabetes. We evaluated the renoprotective effect of the angiotensin-II-receptor antagonist irbesartan in hypertensive patients with type 2 diabetes and microalbuminuria. METHODS: A total of 590 hypertensive patients with type 2 diabetes and microalbuminuria were enrolled in this multinational, randomized, double-blind, placebo-controlled study of irbesartan, at a dose of either 150 mg daily or 300 mg daily, and were followed for two years. The primary outcome was the time to the onset of diabetic nephropathy, defined by persistent albuminuria in overnight specimens, with a urinary albumin excretion rate that was greater than 200 microg per minute and at least 30 percent higher than the base-line level. RESULTS: The base-line characteristics in the three groups were similar. Ten of the 194 patients in the 300-mg group (5.2 percent) and 19 of the 195 patients in the 150-mg group (9.7 percent) reached the primary end point, as compared with 30 of the 201 patients in the placebo group (14.9 percent) (hazard ratios, 0.30 [95 percent confidence interval, 0.14 to 0.61; P< 0.001] and 0.61 [95 percent confidence interval, 0.34 to 1.08; P=0.081 for the two irbesartan groups, respectively). The average blood pressure during the course of the study was 144/83 mm Hg in the placebo group, 143/83 mm Hg in the 150-mg group, and 141/83 mm Hg in the 300-mg group (P=0.004 for the comparison of systolic blood pressure between the placebo group and the combined irbesartan groups). Serious adverse events were less frequent among the patients treated with irbesartan (P=0.02). CONCLUSIONS: Irbesartan is renoprotective independently of its blood-pressure-lowering effect in patients with type 2 diabetes and microalbuminuria.

Adult↗
PubMed2001

Metabolic and functional studies on isolated islets in a new rat model of type 2 diabetes.

In a new experimental type 2 diabetic syndrome, a 40% reduction of pancreatic beta cells was observed by morphometric analysis. In diabetic islets, as compared to control islets, insulin release was decreased in response to high glucose but not to other stimuli, and total glucose oxidation and utilization were unchanged or slightly reduced. The extent of metabolic and functional impairment appeared proportional to the beta-cell loss. However, a substantial decrease was found in protein level and activity (by 77 and 60%, respectively, versus controls) of mitochondrial FAD-glycerophosphate dehydrogenase (mGDH), the key enzyme of the glycerophosphate shuttle. Interestingly, in diabetic islets, as recently reported for mGDH-deficient transgenic mice, definite functional alterations (mainly in response to D-glyceraldehyde) were only obtained upon pharmacological blockade of the second shuttle (i.e. malate-aspartate) responsible for mitochondrial transfer of reducing equivalents. In conclusion, in this diabetes model with reduction of beta-cell mass, the islets, despite decreased mGDH amount and activity, appear metabolically and functionally active in vitro, likely through the intervention of adaptive mechanisms, yet prone to failure in challenging situations.

Aminooxyacetic Acid↗
PubMed2001

Serum levels of the interferon-gamma-inducing cytokine interleukin-18 are increased in individuals at high risk of developing type I diabetes.

AIMS/HYPOTHESIS: Interleukin (IL)-18 is a cytokine primarily produced by macrophages and capable of inducing T lymphocyte synthesis of interferon (IFN)-gamma. An up-regulated synthesis of IFN-gamma with consequential Type I cytokine dominance has been repeatedly shown in Type I (insulin-dependent) diabetes mellitus and thought to be involved in its pathogenesis. Because increased production of IFN-gamma could be secondary to a dysregulated synthesis of IL-18, we compared the circulating levels of IL-18 in patients with newly diagnosed Type I diabetes with those of non-diabetic first-degree relatives and healthy control subjects. METHODS: Serum samples were obtained from healthy control subjects, patients with newly diagnosed Type I diabetes, and their healthy first-degree relatives. The latter were subdivided into "low" and "high" risk prediabetics depending on whether they were negative or positive for two or more of the anti-pancreatic autoantibodies ICA, GAD, IA-2 and IAA. Serum levels of IL-18 were measured by solid-phase ELISA. RESULTS: Interleukin (IL)-18 was above the detection limit of 25 pg/ml in 7 of 40 (17%) healthy control subjects, in 5 of 35 (14%) patients and in 3 of 30 (10%) first-degree relatives at low risk of developing Type I diabetes. In contrast, IL-18 could be detected in 19 of 28 (68%; p < 0.0001) relatives at high risk. The mean serum level of IL-18 was higher in these individuals when compared with the low-risk relatives, patients and control subjects. CONCLUSIONS/INTERPRETATION: IL-18 serum levels are increased selectively during the early, subclinical stage of Type I diabetes.

Adolescent↗
PubMed2001

Tungstate is an effective antidiabetic agent in streptozotocin-induced diabetic rats: a long-term study.

AIMS/HYPOTHESIS: Recent studies have shown the anti diabetic effects of oral sodium tungstate treatment in several animal models of diabetes based on short-term experiments. In this study, we examined the effectiveness of long-term tungstate treatment of streptozotocin-induced-diabetic rats. METHODS: Tungstate was administered to the drinking water of rats for eight months. RESULTS: The treatment resulted in a reduction in serum glucose concentrations in diabetic rats, but no change in glycaemia was detected in healthy rats. Alterations in the hepatic glucose metabolism due to diabetes were almost completely counteracted by tungstate treatment. The partial recovery of glucokinase activity, not found in diabetic animals, normalised glycogen and glucose 6-phosphate concentrations. Tungstate treatment also restored pyruvate kinase activity and fructose 2,6-bisphosphate concentrations. In healthy rats, tungstate treatment did not modify the majority of the hepatic parameters studied. Moreover, tungstate treatment prevented diabetes-induced morphological changes in the kidney and ocular lens and also reduced mortality. Furthermore, no hypoglycaemic episodes or undesirable side effects were observed in treated diabetic or healthy rats. In addition, there is no evidence of intolerance developing after prolonged use. CONCLUSION/INTERPRETATION: Tungstate could play a helpful part in the long-term treatment of diabetes.

Aging↗
PubMed2001

MFP14, a multifunctional emerging protein with immunomodulatory properties, prevents spontaneous and recurrent autoimmune diabetes in NOD mice.

AIMS/HYPOTHESIS: To test the effects of multifunctional protein 14 (MFP14), which shares structural homology with heat shock proteins (HSPs), on the development of Type I (insulin-dependent) diabetes mellitus in NOD mice. METHODS: MFP14 was given to euglycaemic female NOD mice from either the 4th to the 25th or from the 12th until the 35th week, or commencing one day before islet transplantation and until the reappearance of hyperglycaemia. Pancreata from NOD mice treated with multifunctional protein 14 for 14 consecutive weeks until 18 weeks of age were examined histologically for insulitis. Anti-CD3 and/or lipopolysaccharide (LPS)-induced blood levels of interferon (IFN)-gamma, interleukin (IL)-4, IL-10, IL-12 and tumour necrosis factor (TNF)-alpha were measured by ELISA in 10 week-old female NOD mice treated for 6 consecutive weeks with either MFP14 or PBS. Unless otherwise stated, multifunctional protein 14 was administered daily 5 times a week at a dose of 25 microg. Control mice received PBS or, in selected experiments, heat-inactivated MFP14. RESULTS: MFP 14 treated mice had a significantly lower incidence of spontaneous diabetes compared to control mice. The MFP14 was equally effective both upon early and late prophylaxis and the protection persisted until week 50 in mice treated from weeks 4 to 25. Insulitis was significantly reduced by the MFP14. The MFP14 also delayed recurrence of hyperglycaemia in syngeneic islet-transplanted NOD mice. Although MFP14 reduced anti-CD3 and/or LPS-induced blood levels of IFN-gamma, TNF-alpha and IL-12 it increased IL-4 and IL-10. CONCLUSION/INTERPRETATION: The MFP14 could be a possible candidate for the prevention or early treatment of human Type I (insulin-dependent) diabetes mellitus.

Animals↗
PubMed2001

P2 receptor agonists stimulate insulin release from human pancreatic islets.

Although P2 receptors for adenosine 5'-triphosphate (ATP) and/or adenosine 5'-diphosphate (ADP) have been characterized in mammalian pancreatic beta cells, no evidence for an insulin-secreting effect of P2 receptor agonists has been reported as yet in humans. The present study aimed at investigating whether P2 receptor agonists could stimulate insulin release in human pancreatic islets obtained from brain-dead organ donors. Experiments were performed using different glucose concentrations and insulin was measured by radioimmunoassay. When the glucose concentration (8.3 mmol/L) was slightly stimulating for insulin release, alpha,beta-methylene ATP (200 micromol/L) and ADPbetaS (50 micromol/L) similarly amplified insulin secretion: both compounds induced a threefold increase in insulin response. In the presence of a nonstimulating glucose concentration (3.0 mmol/L), only alpha,beta-methylene ATP could induce a significant 1.4-fold increase in insulin release, ADPbetaS being completely ineffective. These results give evidence that P2 receptor agonists are effective in stimulating insulin release in humans, the effect of the P2Y agonist being essentially glucose dependent.

Adenosine Diphosphate↗
PubMed2001

High glucose concentration favors the selective secretion of islet amyloid polypeptide through a constitutive secretory pathway in human pancreatic islets.

We studied the contribution of the constitutive and the regulated pathways to the total secretion of islet amyloid polypeptide (IAPP) in human pancreatic islets after prolonged culture at either 5.5 or 24.4 mM glucose. In islets cultured in low concentrations of glucose, the secretion of IAPP in response to glucose was unaffected by brefeldin A (BFA) and completely blocked by ethyleneglycoltetraacetic acid. In islets cultured in high glucose concentrations, it was strongly inhibited by both agents. BFA had no effect on the glucose-induced insulin secretion. The determination of the islet peptide contents and the mRNA levels revealed a several-fold increase in the IAPP/insulin molar ratio of islets cultured in high glucose concentrations. Thus, prolonged exposure of human islets to high concentrations of glucose results in an increase in the synthesis of IAPP with respect to insulin. As a result, the release of IAPP through a mechanism sensitive to BFA is favored. These data support the hypothesis that IAPP and insulin are regulated in a noncoordinated way in human pancreatic islets.

Amyloid↗
PubMed2001

Hepatic nuclear factor 1-alpha directs nucleosomal hyperacetylation to its tissue-specific transcriptional targets.

Mutations in the gene encoding hepatic nuclear factor 1-alpha (HNF1-alpha) cause a subtype of human diabetes resulting from selective pancreatic beta-cell dysfunction. We have analyzed mice lacking HNF1-alpha to study how this protein controls beta-cell-specific transcription in vivo. We show that HNF1-alpha is essential for the expression of glut2 glucose transporter and L-type pyruvate kinase (pklr) genes in pancreatic insulin-producing cells, whereas in liver, kidney, or duodenum tissue, glut2 and pklr expression is maintained in the absence of HNF1-alpha. HNF1-alpha nevertheless occupies the endogenous glut2 and pklr promoters in both pancreatic islet and liver cells. However, it is indispensable for hyperacetylation of histones in glut2 and pklr promoter nucleosomes in pancreatic islets but not in liver cells, where glut2 and pklr chromatin remains hyperacetylated in the absence of HNF1-alpha. In contrast, the phenylalanine hydroxylase promoter requires HNF1-alpha for transcriptional activity and localized histone hyperacetylation only in liver tissue. Thus, different HNF1-alpha target genes have distinct requirements for HNF1-alpha in either pancreatic beta-cells or liver cells. The results indicate that HNF1-alpha occupies target gene promoters in diverse tissues but plays an obligate role in transcriptional activation only in cellular- and promoter-specific contexts in which it is required to recruit histone acetylase activity. These findings provide genetic evidence based on a live mammalian system to establish that a single activator can be essential to direct nucleosomal hyperacetylation to transcriptional targets.

Acetylation↗
PubMed2001

Identification and functional analysis of mutations in FAD-binding domain of mitochondrial glycerophosphate dehydrogenase in caucasian patients with type 2 diabetes mellitus.

Ca2+-responsive mitochondrial FAD-linked glycerophosphate dehydrogenase (mGPDH) is a key component of the pancreatic beta-cell glucose-sensing device. The purpose of this study was to examine the association of mutations in the cDNA coding for the FAD-binding domain of mGPDH and to explore the functional consequences of these mutations in vitro. To investigate this association in type 2 diabetes mellitus, we studied a cohort of 168 patients with type 2 diabetes and 179 glucose-tolerant control subjects of Spanish Caucasian origin by single-stranded conformational polymorphism analysis. In vitro site-directed mutagenesis was performed in the mGPDH cDNA sequence to reproduce those mutations that produce amino acid changes in a patient with type 2 diabetes. We detected mutations in the mGPDH FAD-binding domain in a single patient, resulting in a Gly to Arg amino acid change at positions 77, 78, and 81 and a Thr to Pro at position 90. In vitro expression of the mutated constructs in Xenopus oocytes resulted in a significantly lower enzymatic activity than in cells expressing the wild-type form of the enzyme. Our results indicate that although mutations in the mGPDH gene do not appear to have a major role in type 2 diabetes mellitus, the reduction in mGPDH enzymatic activity associated with the newly described mGPDH mutations suggests that they may contribute to the disease in some patients.

Aged↗
PubMed2001

Effects of tungstate, a new potential oral antidiabetic agent, in Zucker diabetic fatty rats.

Tungstate was orally administered to 7.5-week-old male Zucker diabetic fatty (ZDF) rats that already showed moderate hyperglycemia (180 +/- 16 mg/dl). The animals became normoglycemic for approximately 10 days. Then, glycemia started to rise again, although it did not reach the initial values until day 24, when levels stabilized at approximately 200 mg/dl for the duration of the experiment. Untreated ZDF rats showed steadily increased blood glucose levels between 7.5 and 10 weeks of age, when they reached a maximum value of 450 +/- 19 mg/dl, which was maintained throughout the experiment. In addition, tolerance to intraperitoneal glucose load improved in treated diabetic rats. Serum levels of triglycerides were elevated in untreated diabetic rats compared with their lean counterparts (ZLC). In the liver of diabetic animals, glucokinase (GK), glycogen phosphorylase a (GPa), liver-pyruvate kinase (L-PK), and fatty acid synthase (FAS) activities decreased by 81, 30, 54, and 35%, respectively, whereas phosphoenolpyruvate carboxykinase (PEPCK) levels increased by 240%. Intracellular glucose-6-phosphate (G6P) decreased by 40%, whereas glycogen levels remained unaffected. Tungstate treatment of these rats induced a 42% decrease in serum levels of triglycerides and normalized hepatic G6P concentrations, GPa activity, and PEPCK levels. GK activity in treated diabetic rats increased to 50% of the values of untreated ZLC rats. L-PK and FAS activity increased to higher values than those in untreated lean rats (1.7-fold L-PK and 2.4-fold FAS). Hepatic glycogen levels were 55% higher than those in untreated diabetic and healthy rats. Tungstate treatment did not significantly change the phosphotyrosine protein profile of primary cultured hepatocytes from diabetic animals. These data suggest that tungstate administration to ZDF rats causes a considerable reduction of glycemia, mainly through a partial restoration of hepatic glucose metabolism and a decrease in lipotoxicity.

Administration, Oral↗
PubMed2001

Flexible meal-related dosing with repaglinide facilitates glycemic control in therapy-naive type 2 diabetes.

OBJECTIVE: This double-blind randomized placebo-controlled parallel group study assessed the efficacy and safety (with particular regard to body weight and hypoglycemia) of repaglinide when used in a flexible mealtime dosing regimen in a situation close to everyday clinical practice. RESEARCH DESIGN AND METHODS: A total of 408 patients with type 2 diabetes considered poorly controlled by diet, but without a history of previous antidiabetic medication, were randomized to receive 0.5 mg repaglinide at mealtimes (increased to 1 mg after 4 weeks depending on blood glucose response) or placebo for 16 weeks. Patients were free to choose a flexible meal pattern, adjusting the dosing schedule from two to four preprandial doses per day in accordance with a "one meal, one dose; no meal, no dose" principle. Additional snacks were not a requirement of the treatment schedule. RESULTS: Treatment with repaglinide significantly improved glycemic control with respect to baseline and placebo, reducing HbA1c by 1.14% from baseline and fasting plasma glucose by 1.8 mmol/l. Improvement in glycemic control was independent of the meal pattern adopted by patients, including those most commonly taking two or four meals daily, with no correlation between meal pattern and risk of hypoglycemia. The improvement in glycemic control was also independent of degree of obesity and age < or =65 or >65 years. There was no significant body weight increase in the repaglinide group. CONCLUSIONS: Mealtime dosing with repaglinide is effective in improving overall glycemic control in type 2 diabetic patients for which control is suboptimal using diet alone. Patients are able to vary their meal pattern from a conventional regimen of three meals daily without compromising control or increasing the risk of adverse events.

Aged↗
PubMed2000

The role of glucose and its metabolism in the regulation of glucokinase expression in isolated human pancreatic islets.

Previous reports concerning the regulation of glucokinase expression in beta cells have been done using cell models from rodent origin. Evidence is lacking so far to implicate the same regulatory mechanisms in human cells. In this study, we investigate the effects of glucose on the expression of glucokinase using isolated human pancreatic islets. High glucose (16.7 mM), in a time-dependent manner, increases the amount of immunoreactive glucokinase (+150% after 7 days culture, P < 0.01) without apparent changes in glucokinase gene expression, suggesting that glucose exerts its effect at a posttranscriptional level. Mannose, but not the nonmetabolized hexoses, 3-O-methylglucose or 2-deoxyglucose, increases glucokinase protein content. Even though these findings are compatible with an involvement of signals derived from glucose metabolism, additional data argue against this hypothesis: (i) a glucokinase inhibitor (mannoheptulose) does not block glucose-induced increase in glucokinase content and (ii) other metabolic fuels (amino acids) are ineffective. We suggest that the glucose molecule, by mechanisms yet to be defined, but probably not involving its metabolism, regulates human glucokinase expression.

Gene Expression Regulation, Enzymologic↗
PubMed2000

Sodium fusidate ameliorates the course of diabetes induced in mice by multiple low doses of streptozotocin.

We studied the effects of the immunosuppressant sodium fusidate (fusidin) on murine immunoinflammatory diabetes mellitus (DM) induced by multiple low doses of streptozotocin (SZ). Fusidin was given by gavage to three strains of mice (C57KsJ, C57BL/6, CD1) at doses 10 or 100 mg/kg body weight every other day. The drug was administered as an early or late prophylactic regime starting either 1 day prior to the first or after the fifth and last injection of SZ. In both situations the largest dose of fusidin successfully reduced the clinical, chemical and histological signs of DM, the treated mice having significantly lower glycaemic values and milder (often absent) insulitis compared with sham-treated animals or controls given SZ alone. The antidiabetogenic effect was long-lasting as it was maintained up to 1 month after cessation of therapy. In contrast, fusidin prophylaxis failed to prevent development of hyperglycaemia acutely induced by one single and high (160 mg/kg) dose of SZ, which is a model of DM primarily due to the toxic action of SZ on the beta cells and does not involve immunopathogenetic mechanisms. On day 14 after SZ, fusidin markedly altered the circulating cytokine profile induced in vivo by ConA, reducing the levels of IFN-gamma, IL-2 and TNF-alpha and augmenting the level of IL-6. However, only the inhibitory effect of the drug on the synthesis/release of IFN-gamma seemed to be causally related to its capacity to counteract the SZ-induced DM. In fact, the disease was prevented by a neutralizing monoclonal antibody (mAb) against IFN-gamma, but not by anti-IL-2 receptor mAb, a soluble form of TNF-receptor type 1 or recombinant human IL-6. The prevention of disease by fusidin was also partly reversed by exogenously administered recombinant mouse IFN-gamma. The data provide further in-vivo evidence for the anti-diabetogenic and immunomodulatory properties of fusidin and indicate that this drug could have a role in prevention and treatment of human type 1 DM.

Animals↗
PubMed2000

White coat hypertension in type 1 diabetic patients without nephropathy.

The aim of our study was to determine the prevalence of white coat hypertension (WCH) in type 1 diabetic patients. Therefore, ambulatory blood pressure monitoring (ABPM) and 24-h urinary albumin excretion (UAE) were determined in 47 patients with type 1 diabetes mellitus (27 with new diagnosis of hypertension by office blood pressure (BP) measurement and 20 with normotension). WCH was diagnosed in 20 patients (74%). Patients with WCH presented higher values of systolic and diastolic BP and UAE than normotensive patients. The results indicate that in type 1 diabetes mellitus WCH is very frequent. Thus, WCH may represent a potential risk for the development of diabetic complications, mainly diabetic nephropathy.

Adult↗