Flavanols from chocolate appear to increase nitric oxide bioavailability, protect vascular endothelium, and decrease cardiovascular disease (CVD) risk factors. We sought to test the effect of flavanol-rich dark chocolate (FRDC) on endothelial function, insulin sensitivity, beta-cell function, and blood pressure (BP) in hypertensive patients with impaired glucose tolerance (IGT). After a run-in phase, 19 hypertensives with IGT (11 males, 8 females; 44.8 +/- 8.0 y) were randomized to receive isocalorically either FRDC or flavanol-free white chocolate (FFWC) at 100 g/d for 15 d. After a wash-out period, patients were switched to the other treatment. Clinical and 24-h ambulatory BP was determined by sphygmometry and oscillometry, respectively, flow-mediated dilation (FMD), oral glucose tolerance test, serum cholesterol and C-reactive protein, and plasma homocysteine were evaluated after each treatment phase. FRDC but not FFWC ingestion decreased insulin resistance (homeostasis model assessment of insulin resistance; P < 0.0001) and increased insulin sensitivity (quantitative insulin sensitivity check index, insulin sensitivity index (ISI), ISI(0); P < 0.05) and beta-cell function (corrected insulin response CIR(120); P = 0.035). Systolic (S) and diastolic (D) BP decreased (P < 0.0001) after FRDC (SBP, -3.82 +/- 2.40 mm Hg; DBP, -3.92 +/- 1.98 mm Hg; 24-h SBP, -4.52 +/- 3.94 mm Hg; 24-h DBP, -4.17 +/- 3.29 mm Hg) but not after FFWC. Further, FRDC increased FMD (P < 0.0001) and decreased total cholesterol (-6.5%; P < 0.0001), and LDL cholesterol (-7.5%; P < 0.0001). Changes in insulin sensitivity (Delta ISI - Delta FMD: r = 0.510, P = 0.001; Delta QUICKI - Delta FMD: r = 0.502, P = 0.001) and beta-cell function (Delta CIR(120) - Delta FMD: r = 0.400, P = 0.012) were directly correlated with increases in FMD and inversely correlated with decreases in BP (Delta ISI - Delta 24-h SBP: r = -0.368, P = 0.022; Delta ISI - Delta 24-h DBP r = -0.384, P = 0.017). Thus, FRDC ameliorated insulin sensitivity and beta-cell function, decreased BP, and increased FMD in IGT hypertensive patients. These findings suggest flavanol-rich, low-energy cocoa food products may have a positive impact on CVD risk factors.
Hyperuricemia is commonly associated with traditional risk factors such as dysglicemia, dyslipidemia, central obesity and abnormal blood pressure, i.e. the metabolic syndrome. Concordantly, recent studies have revived the controversy over the role of circulating uric acid, hyperuricemia, and gout as an independent prognostic factor for cardiovascular morbidity and mortality. In this regard, different studies also evaluated the possible role of xanthine inhibitors in inducing blood pressure reduction, increment in flow-mediated dilation, and improved cardiovascular prognosis in various patient settings. The vast majority of these studies have been conducted with either allopurinol or its active metabolite oxypurinol, i.e. two purine-like non-selective inhibitors of xanthine oxidase. More recently, the role of uric acid as a risk factor for cardiovascular disease and the possible protective role exerted by reduction of hyperuricemia to normal level have been evaluated by the use of febuxostat, a selective, non purine-like xanthine oxidase inhibitor. In this review, we will report current evidence on hyperuricemia in cardiovascular disease. The value of uric acid as a biomarker and as a potential therapeutic target for tailored old and novel “cardiometabolic” treatments will be also discussed.
Increased biochemical measures of ECA were associated with ED independent of coexisting VRFs and overt vascular damage, suggesting that ED is a sentinel of early atherosclerosis.
Recent evidence indicates the presence of p21 Ras and of a protein with characteristics similar to mitogen-activated protein kinases (MAPKs), also known as extracellular signal-regulated kinases (ERKs), in mammalian spermatozoa, suggesting the occurrence of the Ras/ERK cascade in these cells. In the present study we investigated the subcellular localization of ERKs and their biological functions in human spermatozoa. Immunohistochemistry, immunofluorescence, confocal microscopy, and immunoelectron microscopy demonstrated localization of ERKs in the postacrosomal region of spermatozoa. After stimulation of acrosome reaction with the calcium ionophore A23187 and progesterone, ERKs were mostly localized at the level of the equatorial region, indicating redistribution of these proteins in acrosome-reacted spermatozoa. Two proteins of 42 and 44 kDa that are tyrosine phosphorylated in a time-dependent manner during in vitro capacitation were identified as p42 (ERK-2) and p44 (ERK-1) by means of specific antibodies. The increase in tyrosine phosphorylation of these proteins during capacitation was accompanied by increased kinase activity, as determined by the ability of ERK-1 and ERK-2 to phosphorylate the substrate myelin basic protein. The role of this activity in the occurrence of sperm capacitation was also investigated by using PD098059, an inhibitor of the MAPK cascade. The presence of this compound during in vitro capacitation inhibits ERK activation and significantly reduces the ability of spermatozoa to undergo the acrosome reaction in response to progesterone. Since only capacitated spermatozoa are able to respond to progesterone, these data strongly indicate that ERKs are involved in the regulation of capacitation. In summary, our data demonstrate the presence of functional ERKs in human spermatozoa and indicate that these enzymes are involved in activation of these cells during capacitation, providing new insight in clarifying the molecular mechanisms and the signal transduction pathways of this process.
Endothelium homeostasis alterations govern the pathogenesis of cardiovascular diseases. Several studies show that vitamins anti-oxidant proprieties rescue the endothelial functions adversely affected by oxidative stress in several diseases. We investigated the vitamin D anti-oxidant potential in human endothelial cells exposed to H2O2 oxidative stress. Vitamin D protected endothelial cells against H2O2 oxidative stress counteracting the superoxide anion generation, the apoptosis and blocking the extrinsic caspase cascade by positively controlling phospho-active ERKs level. MEKs/ERKs inhibitor U0126 reverted the vitamin D anti-oxidant effects. Characterizing the vitamin D downstream effector, we found that vitamin D up-regulated SirT-1 and reverted the SirT-1 down-regulation induced by H2O2. ERKs activation by vitamin D strictly correlated with SirT-1 protein accumulation since both MEKs/ERKs inhibition and ERK1/2 silencing decreased SIRT-1. SirT-1 inhibition by Sirtinol reverted the vitamin D anti-oxidant effects. Thus, vitamin D significantly reduced the endothelial malfunction and damage caused by oxidative stress, through the activation of MEKs/ERKs/SirT-1 axis.
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 kidneytransplanted patients underwent islet transplantation and were divided into two groups: successful islet-kidney transplantation (SI-K; 21 patients, fasting C-peptide serum concentration Ͼ0.5 ng/ml for Ͼ1 year) and unsuccessful islet-kidney transplantation (UI-K; 13 patients, fasting C-peptide serum concentration Ͻ0.5 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 ϭ 0.04), lower cardiovascular death rate (SI-K 1/21 vs. UI-K 4/13, 2 ϭ 3.9, P ϭ 0.04), and lower intima-media thickness progression than the UI-K group (SI-K group: ⌬1-3 years Ϫ13 Ϯ 30 m vs. UI-K group: ⌬1-3 years 245 Ϯ 20 m, P ϭ 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 Ϯ 4.5% vs. UI-K 0.5 Ϯ 2.7%, P ϭ 0.02), higher basal NO (SI-K 42.9 Ϯ 6.5 vs. UI-K 20.2 Ϯ 6.8 mol/l, P ϭ 0.02), and lower levels of vWF (SI-K 138.6 Ϯ 15.3 vs. UI-K 180.6 Ϯ 7.0%, P ϭ 0.02) and DDF (SI-K 0.61 Ϯ 0.22 vs. UI-K 3.07 Ϯ 0.68 g/ml, P Ͻ 0.01). C-peptide-tocreatinine 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. Diabetes Care 26:1129 -1136, 2003I slet transplantation, particularly after kidney transplantation, is an alternative to pancreas transplantation to restore endogenous insulin secretion (1-7). Islet transplantation is a safe procedure leading to an improvement of glycometabolic control and of protein and lipid metabolism (1,3,6 -8). The benefits of the improvement of glycometabolic control alone on macroangiopathy are unknown (9,10).Patients with type 1 diabetes are at high risk for several cardiovascular disorders, such as coronary artery disease, stroke, peripheral arterial disease, cardiomyopathy, and congestive heart failure (11). These risks are particularly high in patients with uremia and type 1 diabetes, even after kidney transplantation (12). A worsening of carotid lesion has been observed in patients undergoing kidneyalone transplantation (13). High levels of von Willebrand factors (vWF) and Ddimer fragments (DDFs), and impaired endothelial-dependent dilation (EDD) are commonly involved in development of atherosclerosis (14). In particular, endothelium modulates platelet adhesion, macrophage migration, lipid transp...
Endothelin-1 (ET-1) is a potent vasoactive and mitogenic peptide produced by the vascular endothelium. In this study, we evaluated whether insulin stimulates ET-1 secretion by human endothelial cells derived from umbilical cord veins and by human permanent endothelial hybrid cells Ea.hy 926. Moreover, to provide evidence that insulin may stimulate ET-1 secretion in vivo, plasma ET-1 levels were evaluated in 7 type II diabetic normotensive males (mean age, 54.3 +/- 4.0 yr) during 2-h hyperinsulinemic euglycemic clamps (287 pmol insulin/m2.min-1) as well as in 12 obese hypertensive males (mean age, 44.2 +/- 4.6 yr) before and after a 12-week period of caloric restriction. Our results showed that insulin stimulated ET-1 release from cultured endothelial cells in a dose-dependent fashion. ET-1 release persisted for 24 h and was also observed at physiological insulin concentrations (10(-9) mol/L). The insulin-induced ET-1 secretion was inhibited by genistein, a tyrosine kinase inhibitor, and by cycloheximide, a protein synthesis inhibitor, suggesting that it requires de novo protein synthesis rather than ET-1 release from intracellular stores. In the in vivo experiments, plasma ET-1 levels rapidly increased during euglycemic hyperinsulinemic clamps (from 0.76 +/- 0.18 pg/mL at time zero to 1.65 +/- 0.21 pg/mL at 60 min; P < 0.05) and persisted elevated until the end of insulin infusion (1.37 +/- 0.37 pg/mL at 120 min; P < 0.05 vs. time zero). In obese hypertensives, plasma ET-1 levels significantly decreased after 12 weeks of caloric restriction (from 0.85 +/- 0.51 to 0.48 +/- 0.28 pg/mL; P < 0.04). The decrease in body weight induced by caloric restriction was accompanied by a significant reduction in fasting insulin levels (from 167.2 +/- 94.0 to 98.9 +/- 44.9 pmol/L; P < 0.05) which correlated with the reduction in plasma ET-1 levels (r = 0.78; P < 0.003). In conclusion, our data show that insulin stimulates both in vitro and in vivo ET-1 secretion. Such interaction could play a significant role in the development of atherosclerotic lesions in hyperinsulinemic conditions.
C-reactive protein (CRP) is the first acute phase protein that has been described in the literature. It is phylogenetically ancient and - with serum amyloid P - belongs to proteins named as "pentraxin". After being considered a marker of acute inflammation for several decades and fruitfully used in clinical practice, CRP has been recently considered as a potential contributor to inflammatory diseases including atherosclerosis as well as a marker of cardiovascular risk. With regard to the first topic, inflammation is now believed to represent the underlying mechanism leading to the formation of human atheroma and favouring both the destabilization of vulnerable plaques and the formation of occlusive thrombi. In this regard, numerous studies indicated that modest changes in circulating CRP levels, as detected by highly sensitive methods, can be extremely useful in predicting cardiovascular and perhaps cerebrovascular diseases in apparently healthy individuals as well as in patients affected by atherosclerosis. Subjects manifesting with identical low density cholesterol and/or blood pressure levels have different rates of cardiovascular accidents on the basis of different circulating CRP concentrations. In addition, women with identical cardiovascular risk profiles developed more type 2 diabetes in the presence of higher circulating CRP levels and thereby are expected to display divergent cardiovascular prognosis. Therefore, even slight changes in circulating CRP concentrations - assuming that blood is collected appropriately and CRP is measured with correct methods - could help clinicians in defining individual cardiovascular risk. In this review, we have firstly described the current understanding of the structure of CRP, its function, and interaction with the vascular endothelial cell. Then, we have discussed how to measure circulating CRP and the more recent findings on the suggested role of circulating CRP as a novel cardiovascular risk factor.
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