Nature and Cognitive Perception of 4 Different Breakfast Meals Influence Satiety-Related Sensations and Postprandial Metabolic Responses but Have Little Effect on Food Choices and Intake Later in the Day in a Randomized Crossover Trial in Healthy Men.

Background: Regular breakfast consumption is associated with better health status and healthier food intake throughout the day, but this association is a complex interaction of several factors. Objective: This study aimed to investigate the effect of nutritional and cognitive-perceived characteristics of breakfast on metabolic and behavioral variables related to food intake. Methods: The study was a randomized, crossover, controlled trial, with 4 experimental conditions consisting of 3 iso-energetic breakfasts and 1 energy-free control meal. Breakfasts had similar nutritional profiles but differed for glycemic index (GI), glycemic load (GL), and perceived healthiness, satiety, palatability, or energy content. Fifteen healthy normal-weight men [means ± SDs; age: 24 ± 2 y; body mass index (BMI; kg/m2) 23.4 ± 1.6] underwent each experimental condition in random order during 4 different weeks, separated by ≥1-wk washout. On the third day of each intervention week, postprandial blood variables (with insulin as primary outcome), satiety ratings, and food intake during an ad libitum lunch consumed 4 h after breakfast (secondary outcomes) were measured for each experimental condition. Results: A main effect of time, treatment, and time × treatment was found for postprandial insulin, glucose, and nonesterified fatty acids (P < 0.001 for all) after having the 3 iso-energetic breakfasts or the energy-free control one. Postprandial satiety was similar for the 3 energy-containing breakfasts, but higher when compared with the energy-free control (P < 0.001). No difference in energy intake was observed for the ad libitum lunch, whereas prolonged breakfast skipping was compensated by an increase (around +10%) in the average energy intake during the rest of the day, resulting in no differences in the total daily energy intake among the 4 conditions. Conclusions: Although other advantages might exist for breakfasts based on low-GI/low-GL foods, our findings support the hypothesis that minor differences in nutritional and perceived characteristics of breakfast are of limited importance regarding medium-term energy intake in healthy men. This trial was registered at clinicaltrials.gov as BRNN-014 NCT02516956.

Decreased diabetes risk over 9 year after 18-month oral L-arginine treatment in middle-aged subjects with impaired glucose tolerance and metabolic syndrome (extension evaluation of L-arginine study).

PURPOSE: This study aimed to determine whether L-arginine supplementation lasting for 18 months maintained long-lasting effects on diabetes incidence, insulin secretion and sensitivity, oxidative stress, and endothelial function during 108 months among subjects at high risk of developing type 2 diabetes. METHODS: One hundred and forty-four middle-aged subjects with impaired glucose tolerance and metabolic syndrome were randomized in 2006 to an L-arginine supplementation (6.4 g orally/day) or placebo therapy lasting 18 months. This period was followed by a 90-month follow-up. The primary outcome was a diagnosis of diabetes during the 108 month study period. Secondary outcomes included changes in insulin secretion (proinsulin/c-peptide ratio), insulin sensitivity (IGI/HOMA-IR), oxidative stress (AOPPs), and vascular function. After the 18 month participation, subjects that were still free of diabetes and willing to continue their participation (104 subjects) were further followed until diabetes diagnosis, with a time span of about 9 years from baseline. RESULTS: Although results derived from the 18 month of the intervention study demonstrated no differences in the probability of becoming diabetics, at the end of the study, the cumulative incidence of diabetes was of 40.6% in the L-arginine group and of 57.4% in the placebo group. The adjusted HR for diabetes (L-arginine vs. placebo) was 0.66; 95% CI 0.48, 0.91; p < 0.02). Proinsulin/c-peptide ratio (p < 0.001), IGI/HOMA-IR (p < 0.01), and AOPP (p < 0.05) levels were ameliorated in L-arginine compared to placebo. CONCLUSIONS: These results may suggest that the administration of L-arginine could delay the development of T2DM for a long period. This effect could be mediated, in some extent, by L-arginine-induced reduction in oxidative stress.

Association between new markers of cardiovascular risk and hepatic insulin resistance in those at high risk of developing type 2 diabetes.

AIM/HYPOTHESIS: Hepatic insulin resistance (HIR) is considered to be an independent predictor of metabolic disorders and plays an important role in systemic inflammation, which contributes to abnormalities in cardiovascular disease (CVD) risk factors. The aim of this study was to investigate the relationship between HIR and new markers of cardiovascular risks, including leptin/adiponectin ratio (L/A), lipoprotein(a) [Lp(a)], and tumor necrosis factor alpha (TNF-α), at comparable whole body insulin sensitivity in non-diabetic individuals with or without CVD and at high risk of developing type 2 diabetes. METHODS: The HIR index, L/A, Lp(a), and TNF-α were measured in 50 participants with CVD and in 200 without CVD (1:4 ratio). These were also matched for the homeostatic model assessment for insulin resistance (HOMA-IR) and Matsuda-insulin sensitivity index (ISI) in an observational study design. RESULTS: The HIR index (1.52 ± 0.14 vs. 1.45 ± 0.17, p < 0.02), L/A (3.22 ± 3.10 vs. 2.09 ± 2.27, p < 0.004), and levels of Lp(a) (66.6 ± 49.5 vs. 37.9 ± 3 6.8 mg/dL, p < 0.0001) and TNF-α (18.9 ± 21.8 vs. 5.4 ± 7.1 pg/mL, p < 0.0001) were higher in those with CVD than those without CVD. HOMA-IR and ISI were not significantly different (p = 0.88 and p = 0.35, respectively). The HIR index was directly correlated with L/A (r = 0.41, p < 0.0001), Lp(a) (r = 0.20, p < 0.002), TNF- α (r = 0.14, p < 0.03), and diastolic blood pressure (DBP) (r = 0.13, p < 0.03). The stepwise model analysis showed that L/A, Lp(a), and TNF-α explained about 20% of the variation in the HIR indices of all the participants (p < 0.02). CONCLUSIONS/INTERPRETATIONS: Our results suggest a positive association between HIR and new markers of cardiovascular risk [L/A, Lp(a), and TNF- α] at comparable whole body insulin sensitivity in those with or without CVD and at high risk of developing type 2 diabetes.

Long lasting protective effects of early l-arginine treatment on endothelium in an in vitro study.

BACKGROUND & AIMS: Excess nutrient supply, such as high fat and high glucose intake, promotes oxidative stress and advanced glycation end products accumulation. Oxidative stress and AGE accumulation cause pathological elevation of arginase activity and pro-inflammatory signaling implicated in endothelial dysfunction. Several studies showed positive effects of l-arginine supplementation in endothelial function but little is currently known about the role of l-arginine as prevention of endothelial dysfunction caused by excessive nutrient supply (overfeeding). Our aim was to evaluate a possible protective effect of l-arginine on endothelial dysfunction caused by excessive nutrient supply (overfeeding), using human endothelial cells line in an in vitro study. METHODS: Endothelial EA.hy926 cells were pre-treated with 1.72 mM of l-arginine for 24 h and afterwards subjected to nutritional stress (high lipid, high insulin and high glucose concentrations) for further 24 h. After treatment discontinuation, the cells were kept in culture for 48 h, in physiological condition, to evaluate the effects of treatments after normalization. RESULTS: Excess nutrient supply in EA.hy926 cell line showed an increase of oxidative and nitrosative stress, a rise of AGEs production, high arginase activity, leading the cells to acidosis and to cell death. l-arginine pretreatment protects the cells by reducing apoptosis, acidosis, oxidative and nitrosative stress, arginase activity and AGE accumulation. l-arginine pretreatment reduces AGEs generation and accumulation by regulating STAB1 and RAGE gene expression levels. STAB1, acting as receptor scavenger of AGEs, interferes with AGE-RAGE binding and thus prevents activation of intracellular signaling pathways leading to cell damage. Moreover the reduction of oxidative stress promotes a decrease of excessive activation of arginase involved in endothelial dysfunction. The effects of pretreatment with l-arginine last even in the absence of stimuli and despite after treatment discontinuation. CONCLUSIONS: An early l-arginine treatment is able to prevent oxidative stress and AGEs accumulation caused by overfeeding in human endothelial cell line by regulating STAB1/RAGE gene expression and by reducing excess arginase activity. The positive effects of l-arginine pretreatment continue even after treatment discontinuation in normal conditions.

Fasting hyperinsulinemia associates with increased sub-clinical inflammation in first-degree relatives normal glucose tolerant women independently of the metabolic syndrome.

BACKGROUND: To evaluate the influence of gender on the relationship between inflammation and hyperinsulinemia in first-degree relatives of type 2 diabetic patients independently of metabolic syndrome. METHODS: Study group consisted in 217 first-degree relatives with normal glucose tolerance after an oral glucose tolerance test. A logistic analysis, adjusted for age, sex and all the components of the metabolic syndrome, was used to determine the relationship between interleukin-6 (IL-6) and leptin and tertiles of fasting insulin, and to take into account the influence of gender. RESULTS: In the whole cohort, IL-6 and leptin were significantly higher and adiponectin significantly lower in the III tertile when corrected for age, body mass index (BMI) and metabolic syndrome components. In women, but not in men, IL-6 and leptin remained significantly higher when corrected for metabolic syndrome. In the whole cohort and in women, univariate correlations between IL-6 concentrations and the parameters under evaluation showed that IL-6 and leptin were positively correlated with age, BMI, waist, systolic blood pressure (SBP), diastolic blood pressure (DBP), fasting glucose, fasting insulin, Delta AUC insulin area, triglyceride (TG), free fatty acids (FFA) and monocyte chemoattractant protein-1 (MCP-1) and inversely correlated with HDL cholesterol (HDL-C) and adiponectin. In women a forward stepwise linear regression analysis in a model including age, BMI, features of metabolic syndrome, fasting insulin, Delta AUC insulin and insulin sensitivity index (ISI) index revealed that only IL-6 and leptin were independently associated with fasting insulin levels. CONCLUSIONS: In first-degree relatives normal glucose tolerant women, fasting hyperinsulinemia, independently of the presence of metabolic syndrome, is associated with elevated IL-6 and leptin levels, suggesting an increased cardiovascular risk.

A soluble form of the receptor for advanced glycation endproducts (RAGE) is produced by proteolytic cleavage of the membrane-bound form by the sheddase a disintegrin and metalloprotease 10 (ADAM10).

The receptor for advanced glycation endproducts (RAGE) mediates responses to cell danger and stress. When bound by its many ligands (which include advanced glycation endproducts, certain members of the S100/calgranulin family, extracellular high-mobility group box 1, the integrin Mac-1, amyloid beta-peptide and fibrils), RAGE activates programs responsible for acute and chronic inflammation. RAGE is therefore also involved in cancer progression, diabetes, atherosclerosis, and Alzheimer's disease. RAGE has several isoforms deriving from alternative splicing, including a soluble form called endogenous secretory RAGE (esRAGE). We show here that most soluble RAGE, either produced by cell lines or present in human blood, is not recognized by an anti-esRAGE antibody. Cells transfected with the cDNA for full-length RAGE, and thus not expressing esRAGE, produce a form of soluble RAGE, cleaved RAGE (cRAGE) that derives from proteolytic cleavage of the membrane-bound molecules and acts as a decoy receptor. By screening chemical inhibitors and genetically modified mouse embryonic fibroblasts (MEFs), we identify the sheddase ADAM10 as a membrane protease responsible for RAGE cleavage. Binding of its ligand HMGB1 promotes RAGE shedding. Our data do not disprove the interpretation that high levels of soluble forms of RAGE protect against chronic inflammation, but rather suggest that they correlate with high levels of ongoing inflammation.

Shape of the OGTT glucose curve and risk of impaired glucose metabolism in the EGIR-RISC cohort.

OBJECTIVE: To study whether the shape of the oral glucose tolerance test (OGTT)-glucose curve is a stable trait over time; it is associated with differences in insulin sensitivity, ß-cell function and risk of impaired fasting glucose (IFG) and glucose tolerance (IGT) in the Relationship between Insulin Sensitivity and Cardiovascular Disease (RISC) cohort. METHODS: OGTT-glucose curve shape was classified as monophasic, biphasic, triphasic and anomalous in 915 individuals. Oral glucose insulin sensitivity (OGIS), Matsuda insulin sensitivity index (ISI) and ß-cell function were assessed at baseline and 3years apart. RESULTS: The OGTT-glucose curve had the same baseline shape after 3years in 540 people (59%; κ=0.115; p<0.0001). Seventy percent of the participants presented with monophasic OGTT-glucose curve shape at baseline and after 3years (percent positive agreement 0.74). Baseline monophasic shape was associated with significant increased risk of IFG (OR 1.514; 95% CI 1.084-2.116; p=0.015); biphasic shape with reduced risk of IGT (OR 0.539; 95% CI 0.310-0.936) and triphasic shape with reduced risk of IFG (OR 0.493; 95% CI 0.228-1.066; P=0.043) after 3years. Increased risks of IFG (OR 1.509; 95% CI 1.008-2.260; p=0.05) and IGT (OR 1.947; 95% CI 1.085-3.494; p=0.02) were found in people who kept stable monophasic morphology over time and in switchers from biphasic to monophasic shape (OR of IGT=3.085; 95% CI 1.377-6.912; p=0.001). CONCLUSION: After 3years follow-up, the OGTT-glucose shape was stable in 59% of the RISC cohort. Shapes were associated with different OGIS and ß-cell function; persistence over time of the monophasic shape and switch from biphasic to monophasic shape with increased risk of impaired glucose metabolism.

Dietary glycemic index and liver steatosis.

BACKGROUND: Insulin resistance (IR) and liver steatosis (LS) are interlinked metabolic derangements whose prevalence is rapidly increasing, but the effect of dietary carbohydrate quality on LS is unknown. OBJECTIVE: The objective was to describe the relation of IR and LS to total carbohydrate, total dietary fiber, and the glycemic index (GI) and glycemic load of the diet. DESIGN: The study was a cross-sectional evaluation of 247 apparently healthy subjects who had no evidence of viral, toxic, or autoimmune hepatitis and who were unselected for alcohol intake. The homeostasis model assessment index was used as a surrogate measure of IR, and a liver echography was used as a proxy for LS grading. Dietary data were collected by using 3-d food records. Total carbohydrate intake, total dietary fiber, GI, and glycemic load were calculated by using a semiquantitative food-frequency questionnaire concerning the dietary sources of carbohydrates. RESULTS: The prevalence of high-grade LS (HG-LS) increased significantly across quartiles of dietary GI (P for trend < 0.034): HG-LS in the 4th quartile (high GI) was twice that in the first 3 quartiles (low to medium GIs), whereas no relation was observed with total carbohydrates, total dietary fiber, or glycemic load. In insulin-sensitive subjects (first 3 quartiles of homeostasis model assessment index of IR), the prevalence of HG-LS did not differ significantly between GI groups, but, in insulin-resistant subjects (4th quartile of homeostasis model assessment index of IR), it was twice as high in those with high GI as in those with low to medium GIs (P = 0.005). CONCLUSIONS: High-GI dietary habits are associated with HG-LS, particularly in insulin-resistant subjects. Dietary advice on the quality of carbohydrate sources therefore may be a complementary tool for preventing or treating LS of metabolic origin.

Relation of plasma insulin levels to forearm flow-mediated dilatation in healthy volunteers.

Although several observations suggest that insulin resistance/compensatory hyperinsulinemia (IR/CH) has a direct effect on endothelial function, independently of the metabolic abnormalities associated with the defect in insulin action, this relation has not been evaluated in apparently healthy individuals. To address this issue, we measured endothelial-dependent vasodilation in response to forearm ischemia (flow-mediated dilation [FMD]) in 47 nonsmoking, healthy volunteers without known risk factors for atherosclerosis. Measurements were also made of multiple anthropometric, metabolic, and hemodynamic variables related to IR/CH. Decreases in FMD were significantly correlated (analysis of variance for linear trend) with (1) male gender (p = 0.003), (2) waist circumference (p = 0.038), (3) higher fasting plasma insulin (p = 0.015) and triglyceride concentrations (p = 0.023), and (4) lower concentrations of high-density lipoprotein cholesterol (p = 0.001). Multivariate linear regression analysis indicated that only plasma insulin (beta -0.424) was independently associated (p <0.001) with changes in FMD, and individual differences in insulin concentrations, along with gender and brachial artery diameter at baseline, accounted for approximately 39% of the variability in FMD. In conclusion, IR/CH is an independent predictor of decreases in endothelial-dependent vasodilation in apparently healthy individuals, in the absence of traditional risk factors for atherosclerosis.

Insulin resistance, hyperleptinemia and endothelial dysfunction in coronary restenosis.

Impaired insulin sensitivity and endothelial dysfunction are important markers in the development of restenosis after coronary stenting. In addition, new markers of inflammation and endothelium activation, such as increased leptin levels, also have to considered. Many studies have shown that hyperinsulinemia and insulin resistance increase neointimal index measured six months after coronary stenting, and that insulin-sensitizers have beneficial effects by decreasing the rate of restenosis. The role of endothelial dysfunction in the process of restenosis is a fascinating problem. The pathobiology of restenosis in stented arteries is largely related to neointimal hyperplasia, which is dependent upon several factors, such as a reduction in nitric oxide activity that determines endothelial dysfunction and oxidative stress. Abnormal endothelium-dependent vasodilation (related to decreased nitric oxide production in the insulin-resistant state) might be explained by alterations in intracellular signaling and increased endothelin-1 production. Leptin is a hormone related to both fat metabolism and insulin resistance that has been recognized as an independent predictor of coronary restenosis. Chronic hyperleptinemia can reduce the synthesis of nitric oxide owing to the increased oxidative stress in endothelial cells. As a result, the goal in prevention of in-stent restenosis is to develop drugs that are able to act both as insulin- and endothelium-sensitizers.

Islet transplantation is associated with an improvement of cardiovascular function in type 1 diabetic kidney transplant patients.

OBJECTIVE: Cardiovascular mortality and morbidity are major problems in type 1 diabetic patients with end-stage renal disease (ESRD). The aim of this study was to determine whether islet transplantation can improve cardiovascular function in these patients. RESEARCH DESIGN AND METHODS: We assessed various markers of cardiac function at baseline and 3 years later in a population of 42 type 1 diabetic patients with ESRD who received a kidney transplant. Seventeen patients then received an islet transplant that had persistent function as defined by long-term C-peptide secretion (kidney-islet group). Twenty-five patients did not receive a functioning islet transplant (kidney-only group). RESULTS: GHb levels were similar in the two groups, whereas the exogenous insulin requirement was lower in the kidney-islet group with persistent C-peptide secretion. Overall, cardiovascular parameters improved in the kidney-islet group, but not in the kidney-only group, with an improvement of ejection fraction (from 68.2 +/- 3.5% at baseline to 74.9 +/- 2.1% at 3 years posttransplantation, P < 0.05) and peak filling rate in end-diastolic volume (EDV) per second (from 3.87 +/- 0.25 to 4.20 +/- 0.37 EDV/s, P < 0.05). Time to peak filling rate remained stable in the kidney-islet group but worsened in the kidney-only group (P < 0.05). The kidney-islet group also showed a reduction of both QT dispersion (53.5 +/- 4.9 to 44.6 +/- 2.9 ms, P < 0.05) and corrected QT (QTc) dispersion (67.3 +/- 8.3 to 57.2 +/- 4.6 ms, P < 0.05) with higher erythrocytes Na(+)-K(+)-ATPase activity. In the kidney-islet group only, both atrial natriuretic peptide and brain natriuretic peptide levels decreased during the follow-up, with a stabilization of intima-media thickness. CONCLUSIONS: Our study showed that type 1 diabetic ESRD patients receiving a kidney transplant and a functioning islet transplant showed an improvement of cardiovascular function for up to 3 years of follow-up compared with the kidney-only group, who experienced an early failure of the islet graft or did not receive an islet graft.

Acute intravenous L-arginine infusion decreases endothelin-1 levels and improves endothelial function in patients with angina pectoris and normal coronary arteriograms: correlation with asymmetric dimethylarginine levels.

BACKGROUND: We tested the hypothesis that asymmetric dimethylarginine (ADMA) levels could be elevated and influence endothelin-1 and nitric oxide release and action in patients with cardiac syndrome X (CSX). In addition, we evaluated whether an intravenous infusion of L-arginine would improve endothelial function in these subjects. METHODS AND RESULTS: Nine patients with CSX and 14 control subjects underwent a continuous infusion of L-arginine (0.125 g/min) or saline for 120 minutes. Sixty minutes after L-arginine or saline infusions, an intravenous insulin bolus (0.1 U/kg) combined with a euglycemic clamp was performed. Basal ADMA and endothelin-1 levels were higher in patients with CSX than in controls. At the end of the first hour of infusion, compared with saline, L-arginine infusion increased basal forearm blood flow, nitrite and nitrate (NOx), and forearm cGMP release and decreased endothelin-1. After insulin bolus, during saline, insulin-induced NOx, endothelin-1, and forearm cGMP release was almost abolished. Conversely, L-arginine restored a physiological profile of all endothelial variables compared with control subjects. In control subjects, compared with saline infusion, L-arginine infusion did not modify any parameter. ADMA levels were positively correlated with basal endothelin-1 levels and negatively correlated with insulin-induced incremental levels of NOx and forearm cGMP release. CONCLUSIONS: Plasma ADMA levels are increased in patients with CSX, and they are correlated with increases in endothelin-1 and reductions in insulin-induced increments in plasma NOx and cGMP, effects that are reversed by intravenous L-arginine. These data suggest that increased ADMA levels play a role in the abnormal vascular reactivity that is observed in patients with CSX.

Association of insulin resistance, hyperleptinemia, and impaired nitric oxide release with in-stent restenosis in patients undergoing coronary stenting.

BACKGROUND: Previously undiagnosed diabetes, impaired glucose tolerance, and insulin resistance are common in patients with acute myocardial infarction and coronary heart disease (CHD) and might be involved in early restenosis after stent implantation. To evaluate whether markers of insulin resistance syndrome, including leptin, and endothelial dysfunction are related to increased rate of early restenosis, we studied nondiabetic patients with CHD after successful coronary stenting. METHODS AND RESULTS: Both patients with CHD undergoing coronary stenting (120 patients) and control subjects (58 patients) were submitted to an oral glucose tolerance test (OGTT). Fasting leptin levels and fasting and postglucose load insulin sensitivity were assessed. Endothelial function was measured by nitrite and nitrate release (NOx) during OGTT. More than 50% of patients treated with stent implantation presented impaired glucose tolerance or type 2 diabetes, which was previously undiagnosed. These patients also had higher glucose, insulin, and leptin levels than control subjects. Among the stented patients, insulin and leptin levels were higher in patients with restenosis than in patients without restenosis. A significant increase in NOx levels was found during OGTT both in patients without restenosis and in control subjects. On the contrary, NOx profiles were blunted in patients with restenosis. At multiple regression analysis, only DeltaAUC-NOx areas and insulin sensitivity index showed an independent correlation with the minimal lumen diameter at follow-up. CONCLUSIONS: We demonstrated that insulin resistance and endothelial dysfunction are independent predictors of early restenosis after coronary stenting.

Endothelial nitric oxide synthase polymorphisms are associated with type 2 diabetes and the insulin resistance syndrome.

Endothelial nitric oxide synthase (eNOS) variants were previously demonstrated in cardiovascular disease. To evaluate whether eNOS gene variants are associated with insulin resistance and type 2 diabetes, we evaluated polymorphisms in Exon7 (E298D), intron 18 (IVS18 + 27A-->C), and intron 23 (IVS23 + 10G-->T) in 159 type 2 diabetic patients without macrovascular complications and in 207 healthy control subjects. Samples for all hormonal and metabolic variables were obtained after an overnight fast. The D298 and IVS18 + 27C alleles, but not the IVS23 + 10G-->T variant, were significantly more frequent in type 2 diabetic patients than in control subjects. The two- and three-loci haplotype analysis showed that there is a statistically significant association between the eNOS variants and type 2 diabetes. No significant differences were observed in the clinical characteristics of type 2 diabetic patients according to genotypes (except for visceral obesity [waist-to-hip ratio], which was significantly more present in D298 homozygotes). Healthy control subjects homozygous for both D298 and IVS18 + 27C presented higher insulin, C-peptide, and nitric oxide levels, as well as higher HOMA (homeostasis model assessment) values than the double wild-type homozygotes, with values superimposable on those found in type 2 diabetic patients. In conclusion, we described a significant association between eNOS gene polymorphisms and type 2 diabetes, suggesting a new genetic susceptibility factor for hyperinsulinemia, insulin resistance, and type 2 diabetes.

Acute effects of heparin administration on the ischemic threshold of patients with coronary artery disease: evaluation of the protective role of the metabolic modulator trimetazidine.

OBJECTIVES: We sought to assess the effects of heparin and the potential protective effects of trimetazidine (TMZ) on exercise performance, plasma nitric oxide (NO), endothelin-1 (ET-1) and free fatty acid (FFA) release in patients with stable coronary artery disease (CAD). BACKGROUND: Heparin has been shown to reduce the ischemic threshold in patients with CAD. Trimetazidine may affect myocardial substrate utilization by shifting energy production from FFA to glucose oxidation. METHODS: In four consecutive days, nine patients with CAD each received one of the following four regimens: 1) one tablet of placebo the evening before and at 8 AM and 4 PM on the day of the study, 10 ml of saline in a bolus 10 min before exercise, followed by an infusion of the same preparation; 2) placebo at the same times as in the first regimen, 5,000 IU of heparin 10 min before exercise, followed by 1,000 IU/h; 3) 20 mg TMZ at the same times as in the first regimen, 5,000 IU of heparin 10 min before exercise, followed by 1,000 IU/h; or 4) TMZ at the same times as in the first regimen, 10 ml of saline 10 min before exercise, followed by an infusion of the same preparation. RESULTS: During placebo (test 2), heparin reduced the time to 1-mm ST-segment depression and prolonged the recovery time, as compared with the results of test 1. When heparin was administered after TMZ (test 3), the time to 1-mm ST-segment depression and the recovery time were similar to those recorded during saline (test 1). Finally, compared with all study phases, TMZ during saline (test 4) prolonged the time to 1 mm. No changes in NO release were found, whereas ET-1 was decreased at peak exercise and during recovery, when the patients were receiving TMZ (tests 3 and 4). Free fatty acids increased after heparin, both with placebo and TMZ. CONCLUSIONS: In patients with CAD, heparin reduces the ischemic threshold. Trimetazidine reduces the effects of heparin, probably by inhibiting FFA oxidation and enhancing glucose metabolism. The concomitant novel observation of reduced ET-1 release is likely to be also dependent on TMZ-induced improvement of endothelial metabolism or reduction of myocardial ischemia.

Relationship between leptin, insulin, body composition and liver steatosis in non-diabetic moderate drinkers with normal transaminase levels.

OBJECTIVE: Obesity and insulin resistance play a major role in the development of liver steatosis (LS), but also relative leptin resistance has been reported to correlate with LS in humans. Our objective was to investigate the relationship between serum leptin, insulin, obesity and LS in non-diabetic males (n = 74) and postmenopausal females (n = 50) with normal transaminase levels and low-to-moderate alcohol intake. METHODS: A medical history to retrieve information about health status, current medications, alcohol consumption and history of viral or toxic hepatitis; a physical examination including height, weight, waist circumference and blood pressure; a fasting blood draw for the determination of glucose, insulin, leptin, lipid profile, transaminases and uric acid; an oral glucose tolerance test to exclude type 2 diabetes; a dual-energy X-ray absorptiometry scan to assess fat mass (FM) and lean body mass (LBM), and an echography of the liver to assess LS. RESULTS: Fasting leptin and insulin were highly correlated with FM in men (R = 0.767 and R = 0.495 respectively, P < 0.001) and women (R = 0.713 and R = 0.526 respectively, P < 0.001). After correction for FM, leptin showed a significant negative correlation with LBM in men (R = -0.240, P = 0.039), but not in women (R = -0.214, P = 0.132). The positive relationship observed between leptin, insulin and LS persisted after adjustment of leptin and insulin for body composition only in men (R = 0.415, P < 0.001 and R = 0.339, P = 0.003 respectively for leptin and insulin vs LS). Adjusted means (95% confidence intervals) of leptin increased significantly across categories of LS in men even when insulin was considered in the model (absent = 7.1 ng/ml (5.6-8.5), mild = 8.2 ng/ml (7.2-9.2), moderate/severe = 12.1 ng/ml (10.3-14.0); P < 0.001), whereas no significant relationship was observed between insulin and LS after leptin was accounted for. CONCLUSION: Serum concentrations of leptin and insulin are positively correlated in men independently of body composition, but not in postmenopausal women. In men, the steatogenic effect of hyperinsulinemia/insulin resistance in the context of low-to-moderate alcohol consumption appears to be mediated by high concentrations of serum leptin, whereas body fat alone could identify postmenopausal women at high risk for LS.

Hyperinsulinemia predicts hepatic fat content in healthy individuals with normal transaminase concentrations.

Although the prevalence of insulin resistance (IR) and compensatory hyperinsulinemia (CH) is increased in patients with nonalcoholic fatty liver disease, the role of IR/CH in regulation of hepatic fat content in healthy volunteers with normal concentrations of alanine transaminase (ALT) has not been defined. To address this issue, hepatic fat content was quantified by ultrasound in 69 (30 men, 39 women) healthy individuals, without known risk factors for liver disease and with plasma ALT concentrations of less than 30 U/L. Experimental variables quantified included body mass index, waist circumference, systolic and diastolic blood pressures, and fasting plasma glucose, fasting plasma insulin (FPI), and lipid concentrations. Subjects were classified as having no (55%), mild (27%), or moderate to severe (18%) hepatic steatosis on the basis of the ultrasound results. Statistically significant (P < .05-.001) correlations (Spearman rho values) existed between liver fat content and ALT (0.26), body mass index (0.52), waist circumference (0.50), systolic blood pressure (0.28), diastolic blood pressure (0.27), fasting plasma glucose (0.47), FPI (0.56), triglycerides (0.30), and high-density lipoprotein cholesterol (-0.35). Multivariate general discriminant analysis and multiple linear regression analysis indicated that FPI was the only independent predictor (P < .001) of both liver fat content and ALT concentrations. Fasting plasma insulin (a surrogate estimate of IR/CH) predicts hepatic fat content and ALT in healthy volunteers with normal transaminase concentrations, independently of the other anthropometric and metabolic variables measured.

L-arginine-induced vasodilation of the renal vasculature is preserved in uremic type 1 diabetic patients after kidney and pancreas but not after kidney-alone transplantation.

OBJECTIVE: In uremic type 1 diabetic patients, kidney and pancreas transplantation (KP) and kidney-alone transplantation (KD) provide full restoration of normal renal function; however, only KP, i.e., curing diabetes, is expected to prevent endothelial damages. Our aim was to study L-arginine-induced vasodilation of the renal vasculature in uremic type 1 diabetic patients after KP or KD using magnetic resonance (MR). RESEARCH DESIGN AND METHODS: MR quantitative flow measurements were performed in 15 KP patients (mean age 39.0 +/- 1.7 years, 10 men and 5 women), in 11 KD patients (mean age 47.3 +/- 1.9 years, 7 men and 4 women), and in 8 nondiabetic kidney transplant patients (mean age 44.0 +/- 4.8 years, 7 men and 1 woman), who were used as control subjects, to measure renal blood flow and velocity and renal vascular resistance before and immediately after infusion of L-arginine. RESULTS: Renal blood flow and velocity were not different at baseline in KP, KD, and control subjects. In contrast, during L-arginine administration renal blood flow increased significantly in KP subjects (basal 8.4 +/- 0.6 vs. post 9.6 +/- 0.8 ml/s, Delta 14.3 +/- 4.4%, P < 0.05) and in control subjects (basal 9.3 +/- 0.8 vs. post 9.1 +/- 0.8 ml/s, Delta 17.3 +/- 6.2%, P < 0.01), while it remained unchanged in KD subjects (basal 10.0 +/- 0.8 vs. post 11.6 +/- 0.9 ml/s, Delta -1.36 +/- 6.9%, NS). Parallel results have been achieved for renal blood velocity (KP subjects: 20.1 +/- 4.9%, P < 0.01; control subjects: 23.0 +/- 7.99%, P < 0.01; and KD subjects: -0.3 +/- 6.5%; NS). A reduction in renal vascular resistance in response to L-arginine was evident in KP and control subjects but not in KD patients. CONCLUSIONS: L-Arginine vasodilatory response was successfully assessed with MR quantitative flow measurements. KP patients and control subjects, but not those with KD, showed a preserved L-arginine-induced vasodilation of the renal vasculature.

Long-term beneficial effect of islet transplantation on diabetic macro-/microangiopathy in type 1 diabetic kidney-transplanted patients.

OBJECTIVE: Our aim was to evaluate the long-term effects of transplanted islets on diabetic macro-/microangiopathy in type 1 diabetic kidney-transplanted patients. RESEARCH DESIGN AND METHODS: A total of 34 type 1 diabetic kidney-transplanted patients underwent islet transplantation and were divided into two groups: successful islet-kidney transplantation (SI-K; 21 patients, fasting C-peptide serum concentration >0.5 ng/ml for >1 year) and unsuccessful islet-kidney transplantation (UI-K; 13 patients, fasting C-peptide serum concentration <0.5 ng/ml). Patients cumulative survival, cardiovascular death rate, and atherosclerosis progression were compared in the two groups. Skin biopsies, endothelial dependent dilation (EDD), nitric oxide (NO) levels, and atherothrombotic risk factors [von Willebrand factor (vWF) and D-dimer fragment (DDF)] were studied cross-sectionally. RESULTS: The SI-K group showed a significant better patient survival rate (SI-K 100, 100, and 90% vs. UI-K 84, 74, and 51% at 1, 4, and 7 years, respectively, P = 0.04), lower cardiovascular death rate (SI-K 1/21 vs. UI-K 4/13, chi(2) = 3.9, P = 0.04), and lower intima-media thickness progression than the UI-K group (SI-K group: delta1-3 years -13 +/- 30 micro m vs. UI-K group: delta1-3 years 245 +/- 20 micro m, P = 0.03) with decreased signs of endothelial injuring at skin biopsy. Furthermore, the SI-K group showed a higher EDD than the UI-K group (EDD: SI-K 7.8 +/- 4.5% vs. UI-K 0.5 +/- 2.7%, P = 0.02), higher basal NO (SI-K 42.9 +/- 6.5 vs. UI-K 20.2 +/- 6.8 micro mol/l, P = 0.02), and lower levels of vWF (SI-K 138.6 +/- 15.3 vs. UI-K 180.6 +/- 7.0%, P = 0.02) and DDF (SI-K 0.61 +/- 0.22 vs. UI-K 3.07 +/- 0.68 micro g/ml, P < 0.01). C-peptide-to-creatinine ratio correlated positively with EDD and NO and negatively with vWF and DDF. CONCLUSIONS: Successful islet transplantation improves survival, cardiovascular, and endothelial function in type 1 diabetic kidney-transplanted patients.

Elevated heart rate predicts ß cell function in non-diabetic individuals: the RISC cohort.

CONTEXT: Elevated heart rate has been associated with insulin resistance and incident type 2 diabetes but its relationship with ß-cell function is not known. Our aim was to investigate whether baseline heart rate is associated with ß-cell function and hyperglycaemia. METHODS: We used the prospective RISC cohort with 1005 non-diabetic individuals who had an oral glucose tolerance test (OGTT) at baseline and after 3 years. Impaired glucose regulation was defined as a fasting plasma glucose ≥ 6.1 mmol/l or a 2-h plasma glucose ≥ 7.8 mmol/l. Insulin sensitivity was assessed by the OGIS index and insulin secretion and ß-cell glucose sensitivity at both baseline and 3 years. RESULTS: Baseline heart rate was positively related to both fasting (P < 0.0001) and 2 h glucose levels (P = 0.02) at year 3 and predicted the presence of impaired glucose regulation at year 3 in a logistic regression model adjusting for insulin sensitivity at inclusion (OR/10 beats per min: 1.31; 95% CI (1.07-1.61); P = 0.01). Baseline heart rate was associated with lower insulin sensitivity (ß = -0.11; P < .0001), a decrease in both ß-cell glucose sensitivity (ß = -0.11; P = 0.003) and basal insulin secretion rate (ß = -0.11; P = 0.002) at 3 years in an adjusted multivariable regression model. Baseline heart rate predicted the 3-year decrease in ß-cell glucose sensitivity (ß = -0.10; P = 0.007) and basal insulin secretion (ß = -0.12; P = 0.007). CONCLUSIONS: Heart rate predicts ß-cell function and impaired glucose regulation at 3 years in non-diabetic individuals, independently of the level of insulin sensitivity. These findings suggest a possible effect of the sympathetic nervous system on ß-cell dysfunction, which deserves further investigation.