PierMarco Piatti

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 &Dgr;AUC-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.

Total antioxidant capacity of the diet is inversely and independently related to plasma concentration of high-sensitivity C-reactive protein in adult Italian subjects

Inflammation, a risk factor for cardiovascular disease, is associated with low plasma levels of antioxidant vitamins. In addition to vitamins, other antioxidants modulate the synthesis of inflammatory markers in vitro and contribute to the total antioxidant capacity (TAC) of a diet. However, the relationship between dietary TAC and markers of inflammation has never been evaluated in vivo. We investigated the relationship between dietary TAC and markers of systemic (high-sensitivity C-reactive protein (hs-CRP), leucocytes) and vascular (soluble intercellular cell adhesion molecule-1) inflammation in 243 non-diabetic subjects. General Linear Model (GLM) analysis showed a significant (P=0.005) inverse relationship between hs-CRP and quartiles of energy-adjusted dietary TAC, even when recognized modulating factors of inflammation, namely alcohol, fibre, vitamin C, alpha-tocopherol, beta-carotene, BMI, waist circumference, HDL-cholesterol, hypertension, insulin sensitivity and plasma beta-carotene, were included in the model as covariates (P=0.004). The relationship was stronger for subjects with hypertension (P=0.013 v. P=0.109 for normotensive individuals). Among dietary factors, TAC was significantly higher (5.3 (sd 3.0) v. 4.9 (sd 2.7) mmol Trolox/d; P=0.026) in subjects with low plasma hs-CRP (range: 0.0-4.1 mg/l) than in subjects with high plasma hs-CRP (range: 4.2-27.8 mg/l). We conclude that dietary TAC is inversely and independently correlated with plasma concentrations of hs-CRP and this could be one of the mechanisms explaining the protective effects against CVD of antioxidant-rich foods such as fruits, whole cereals and red wine. This could be of particular significance for subjects with high blood pressure.

Hypertriglyceridemia and Hyperinsulinemia Are Potent Inducers of Endothelin-1 Release in Humans

The purpose of the study was to evaluate fasting endothelin-1 levels in subjects with syndrome X, in subjects with insulinoma, and in normal subjects. The single and synergistic contributions of insulin and triglyceride levels to endothelin-1 release were studied in normal subjects. This was achieved by the evaluation of endothelin-1 levels in response to an insulin bolus combined with a euglycemic clamp (protocol A) and during intralipid (test 1) or saline (test 2) infusions lasting 360 min (protocol B). In protocol B, a euglycemic two-step hyperinsulinemic (25 and 125 mU · kg−1 · h−1) clamp was started at 120 min. Subjects with syndrome × showed significantly higher endothelin-1 levels than normal subjects and subjects with insulinoma (7.22 ± 0.89 vs. 2.61 ± 0.38 and 2.49 ± 0.24 pg/ml, P < 0.01). After an insulin bolus, endothelin-1 levels peaked at 10 min (3.71 ± 0.96 pg/ml). The incremental area of endothelin-1 was significantly higher after insulin than after a saline bolus. In test 1, an acute increase in triglyceride levels significantly enhanced endothelin-1 levels, with were further increased by the synergistic contribution of high insulin and triglyceride levels. In test 2, endothelin-1 release was achieved at high insulin levels but remained significantly lower than in test 1. In conclusion, subjects with syndrome × showed higher endothelin-1 levels than normal subjects and subjects with insulinoma. These levels were reproduced in normal subjects by a simultaneous increase in insulin and triglyceride levels.

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.

Oral L-arginine supplementation improves endothelial function and ameliorates insulin sensitivity and inflammation in cardiopathic nondiabetic patients after an aortocoronary bypass

It is known that L-arginine treatment can ameliorate endothelial dysfunction and insulin sensitivity in type 2 diabetes mellitus patients, but little is known on L-arginine effects on these variables in nondiabetic patients with stable cardiovascular disease (coronary artery disease). We evaluated the effects of long-term oral L-arginine treatment on endothelial dysfunction, inflammation, adipokine levels, glucose tolerance, and insulin sensitivity in these patients. Sixty-four patients with cardiovascular disease previously submitted to an aortocoronary bypass and not known for type 2 diabetes mellitus had an oral glucose load to define their glucose tolerance. Thirty-two patients with nondiabetic response were eligible to receive, in a double-blind randomized parallel order, L-arginine (6.4 g/d) or placebo for 6 months. An evaluation of insulin sensitivity index during the oral glucose load, markers of systemic nitric oxide bioavailability and inflammation, and blood flow was performed before and at the end of the treatment in both groups. Compared with placebo, L-arginine decreased asymmetric dimethylarginine levels (P < .01), indices of endothelial dysfunction, and increased cyclic guanosine monophosphate (P < .01), L-arginine to asymmetric dimethylarginine ratio (P < .0001), and reactive hyperemia (P < .05). Finally, L-arginine increased insulin sensitivity index (P < .05) and adiponectin (P < .01) and decreased interleukin-6 and monocyte chemoattractant protein-1 levels. In conclusion, insulin resistance, endothelial dysfunction, and inflammation are important cardiovascular risk factors in coronary artery disease patients; and L-arginine seems to have anti-inflammatory and metabolic advantages in these patients.

Benefits of LixiLan, a Titratable Fixed-Ratio Combination of Insulin Glargine Plus Lixisenatide, Versus Insulin Glargine and Lixisenatide Monocomponents in Type 2 Diabetes Inadequately Controlled on Oral Agents: The LixiLan-O Randomized Trial.

OBJECTIVE To evaluate efficacy and safety of LixiLan (iGlarLixi), a novel titratable fixed-ratio combination of insulin glargine (iGlar) and lixisenatide (Lixi), compared with both components, iGlar and Lixi, given separately in type 2 diabetes inadequately controlled on metformin with or without a second oral glucose-lowering drug. RESEARCH DESIGN AND METHODS After a 4-week run-in to optimize metformin and stop other oral antidiabetic drugs, participants (N = 1,170, mean diabetes duration ∼8.8 years, BMI ∼31.7 kg/m2) were randomly assigned to open-label once-daily iGlarLixi or iGlar, both titrated to fasting plasma glucose <100 mg/dL (<5.6 mmol/L) up to a maximum insulin dose of 60 units/day, or to once-daily Lixi (20 μg/day) while continuing with metformin. The primary outcome was HbA1c change at 30 weeks. RESULTS Greater reductions in HbA1c from baseline (8.1% [65 mmol/mol]) were achieved with iGlarLixi compared with iGlar and Lixi (−1.6%, −1.3%, −0.9%, respectively), reaching mean final HbA1c levels of 6.5% (48 mmol/mol) for iGlarLixi versus 6.8% (51 mmol/mol) and 7.3% (56 mmol/mol) for iGlar and Lixi, respectively (both P < 0.0001). More subjects reached target HbA1c <7% with iGlarLixi (74%) versus iGlar (59%) or Lixi (33%) (P < 0.0001 for all). Mean body weight decreased with iGlarLixi (−0.3 kg) and Lixi (−2.3 kg) and increased with iGlar (+1.1 kg, difference 1.4 kg, P < 0.0001). Documented symptomatic hypoglycemia (≤70 mg/dL) was similar with iGlarLixi and iGlar (1.4 and 1.2 events/patient-year) and lower with Lixi (0.3 events/patient-year). iGlarLixi improved postprandial glycemic control versus iGlar and demonstrated considerably fewer nausea (9.6%) and vomiting (3.2%) events than Lixi (24% and 6.4%, respectively). CONCLUSIONS iGlarLixi complemented iGlar and Lixi effects to achieve meaningful HbA1c reductions, close to near normoglycemia without increases in either hypoglycemia or weight, compared with iGlar, and had low gastrointestinal adverse effects compared with Lixi.

ADMA is independently related to flow-mediated vasodilation in subjects at low cardiovascular risk.

Background  Increased plasma concentrations of asymmetric dimethylarginine (ADMA) contribute to impair endothelial function in patients with established cardiovascular disease (CVD) and/or individuals with clinical syndromes known to increase CVD. However, the impact of ADMA on endothelial function in apparently healthy individuals has not been determined.

The total antioxidant capacity of the diet is an independent predictor of plasma β -carotene

Objective:To investigate the contribution of the total antioxidant capacity (TAC) of the diet to plasma concentrations of β-carotene.Design:Cross-sectional study.Setting:Department of Public Health and Department of Internal Medicine and Biomedical Sciences, University of Parma.Subjects:A total of 247 apparently healthy adult men (n=140) and women (n=107).Methods:A medical history, a physical exam including height, weight, waist circumference and blood pressure measurements, a fasting blood draw, an oral glucose tolerance test and a 3-day food record.Results:We observe a negative trend across quartiles of plasma β-carotene for most biological variables clustering in the insulin resistance syndrome, as well as for traditional and new risk factors for type II diabetes and cardiovascular disease (CVD), including C-reactive protein and γ-glutamyltranspeptidase (P<0.05). Regarding dietary characteristics, energy-adjusted intake of fat, fiber, fruits, vegetables, β-carotene, vitamin C, vitamin E and dietary TAC significantly increased with increasing plasma β-carotene (P<0.05), whereas alcohol intake decreased (P=0.013). Adjusted geometric means (95% confidence interval) of plasma β-carotene significantly increased across quartiles of dietary TAC, even when single dietary antioxidants were considered in the model (QI=0.087 mg/dl (0.073–0.102); QII=0.087 mg/dl (0.075–0.103); QIII=0.114 mg/dl (0.098–0.132) and QIV=0.110 mg/dl (0.093–0.130); P for linear trend=0.026). When the population was divided on the basis of alcohol consumption, this trend was also observed in subjects drinking <20 g alcohol/day (P=0.034), but not in those with higher alcohol intake (P=0.448).Conclusions:Dietary TAC is an independent predictor of plasma β-carotene, especially in moderate alcohol drinkers. This may explain, at least in part, the inverse relationship observed between plasma β-carotene and risk of chronic diseases associated to high levels of oxidative stress (i.e., diabetes and CVD), as well as the failure of β-carotene supplements alone in reducing such risk.Sponsorship:Supported by the European Community IST-2001–33204 ‘Healthy Market’, the Italian Ministry of University and Research COFIN 2001 and the National Research Council CU01.00923.CT26 research projects.

L-Arginine enriched biscuits improve endothelial function and glucose metabolism: A pilot study in healthy subjects and a cross-over study in subjects with impaired glucose tolerance and metabolic syndrome

OBJECTIVE The aim of this study was to evaluate the effects of a new L-arginine-enriched biscuit on endothelial function, insulin sensitivity/secretion and body composition. MATERIALS/METHODS The project was composed of two studies. The first study was an acute pilot postprandial study in 7 healthy subjects that evaluated bio-availability and vascular effects of L-arginine-enriched biscuits that contained 6.6 gL-arginine, 21.9 g carbohydrates, 3.6 g protein, 7.5 g fat and 4.3 g dietary fiber compared with placebo biscuits and 6.6 g powdered L-arginine. Subjects underwent the tests in random order, in at least 14-day intervals. The second study was a double-blind crossover study in 15 obese subjects with IGT and MS. These subjects consumed 6.6 g of L-arginine-enriched biscuits or placebo biscuits in a 1600 kcal diet. Each study period lasted 2 weeks with a 2-week washout in between. Endothelial function, glucose tolerance, insulin sensitivity and insulin secretion were evaluated at the end of each intervention period. RESULTS In the first study, the groups that received the L-arginine-enriched biscuits and the powdered L-arginine had similarly increased L-arginine, NOx and cGMP levels and post-ischemic blood flow (PI-BF). In both cases, these levels were significantly higher than those in the placebo biscuit recipient group. In the second study, the L-arginine-enriched biscuit recipient group displayed increased L-arginine, NOx, cGMP, PI-BF, and Matsuda index levels, whereas their circulating glucose, proinsulin/insulin ratio and fat mass were decreased compared with the placebo biscuit recipient group. CONCLUSIONS L-Arginine-enriched biscuits with low sugar and protein content enhance endothelial function and improve glucose metabolism, insulin sensitivity and insulin secretion in subjects with IGT and MS.

Intake of the plant lignans matairesinol, secoisolariciresinol, pinoresinol, and lariciresinol in relation to vascular inflammation and endothelial dysfunction in middle age-elderly men and post-menopausal women living in Northern Italy

BACKGROUND AND AIMS It has been suggested that lignan intake may decrease the risk for cardiovascular disease (CVD) by modifying traditional risk factors as well as aortic stiffness. However, the role of dietary lignans on the vascular system is largely unknown. The objective was to investigate whether dietary intake of plant lignans in a free-living population was associated with markers of vascular inflammation and function. METHODS AND RESULTS We performed a cross-sectional study in 242 (151 males) men and post-menopausal women. Anthropometric characteristics and lignan intake were evaluated. Soluble intercellular adhesion molecule-1 (sICAM-1), insulin, high-sensitive C-reactive protein, glucose, total cholesterol, HDL-cholesterol and triacylglycerols were measured in fasting blood samples. Brachial flow-mediated dilation (FMD) measurements were available for 101 subjects (56 males). Median (interquartile range) daily intake of matairesinol (MAT), secoisolariciresinol (SECO), pinoresinol (PINO), lariciresinol (LARI), and total lignans was 20.9 microg (17.4), 335.3 microg (289.1), 96.7 microg (91.1), 175.7 microg (135.8), and 665.5 microg (413.7), respectively, as assessed by 3-day weighed food record. Plasma concentrations of sICAM-1 (whole sample) significantly decreased (mean (95%CI) = 358 microg/L (320-401), 276 microg/L (252-303), 298 microg/L (271-326), and 269 microg/L (239-303), P per trend 0.013) and FMD values (FMD sub-group) significantly increased (4.1% (2.2-6.0), 5.7% (4.3-7.2), 6.4% (4.9-7.8), and 8.1% (6.3-10.0), P per trend 0.016) across quartiles of energy-adjusted MAT intake, even after adjustment for relevant clinical and dietary variables. Intake of SECO was also inversely related to plasma sICAM-1 (P per trend 0.018), but not to FMD values. No relationship between intake of PINO, LARI or total lignans and either sICAM-1 or FMD values was observed. CONCLUSIONS Higher MAT intakes in the context of a typical Northern Italian diet are associated to lower vascular inflammation and endothelial dysfunction, which could have some implications in CVD prevention.