Angela Tesse

Shed Membrane Particles From T Lymphocytes Impair Endothelial Function and Regulate Endothelial Protein Expression

Background—Microparticles (MPs) are membrane vesicles with procoagulant and proinflammatory properties released during cell activation. The present study was designed to dissect the effects evoked by T lymphocyte–derived MPs on vascular function. Methods and Results—MPs were produced by treatment of the human lymphoid CEM T cell line with actinomycin D or phytohemagglutinin. Incubation of mouse aortic rings with 30 nmol/L MPs resulted in a time-dependent impairment of acetylcholine-induced relaxation of precontracted vessels, with a maximal reduction after 24 hours. MPs also impaired shear stress–induced dilatation of mouse small mesenteric arteries by affecting the nitric oxide (NO) and prostacyclin but not the endothelium-derived hyperpolarizing factor components of the response. However, neither alteration of calcium signaling in response to agonists nor reduction of cyclooxygenase-1 expression accounted for the impairment of the NO and prostacyclin components of the endothelial response. The effect of MPs was rather because of a decrease in expression of endothelial NO synthase and an overexpression of caveolin-1. Furthermore, lymphocyte-derived MPs from diabetic patients or in vivo circulating MPs from either diabetic or HIV-infected patients reduced endothelial NO synthase expression. Finally, the effects of MPs on endothelial cells were not driven through CD11a/CD18 adhesion molecules or the Fas/FasL pathway. Conclusions—MPs from T cells induce endothelial dysfunction in both conductance and resistance arteries by alteration of NO and prostacyclin pathways. MPs regulate protein expression for endothelial NO synthase and caveolin-1. These data contribute to a better understanding of the deleterious effects of enhanced circulating MPs observed in disorders with cardiovascular or immune complications.

Red wine polyphenols prevent metabolic and cardiovascular alterations associated with obesity in Zucker fatty rats (Fa/Fa).

Background Obesity is associated with increased risks for development of cardiovascular diseases. Epidemiological studies report an inverse association between dietary flavonoid consumption and mortality from cardiovascular diseases. We studied the potential beneficial effects of dietary supplementation of red wine polyphenol extract, Provinols™, on obesity-associated alterations with respect to metabolic disturbances and cardiovascular functions in Zucker fatty (ZF) rats. Methodology/Principal Findings ZF rats or their lean littermates received normal diet or supplemented with Provinols™ for 8 weeks. Provinols™ improved glucose metabolism by reducing plasma glucose and fructosamine in ZF rats. Moreover, it reduced circulating triglycerides and total cholesterol as well as LDL-cholesterol in ZF rats. Echocardiography measurements demonstrated that Provinols™ improved cardiac performance as evidenced by an increase in left ventricular fractional shortening and cardiac output associated with decreased peripheral arterial resistances in ZF rats. Regarding vascular function, Provinols™ corrected endothelial dysfunction in aortas from ZF rats by improving endothelium-dependent relaxation in response to acetylcholine (Ach). Provinols™ enhanced NO bioavailability resulting from increased nitric oxide (NO) production through enhanced endothelial NO-synthase (eNOS) activity and reduced superoxide anion release via decreased expression of NADPH oxidase membrane sub-unit, Nox-1. In small mesenteric arteries, although Provinols™ did not affect the endothelium-dependent response to Ach; it enhanced the endothelial-derived hyperpolarizing factor component of the response. Conclusions/Significance Use of red wine polyphenols may be a potential mechanism for prevention of cardiovascular and metabolic alterations associated with obesity.

Estrogen Receptor Alpha as a Key Target of Red Wine Polyphenols Action on the Endothelium

Background A greater reduction in cardiovascular risk and vascular protection associated with diet rich in polyphenols are generally accepted; however, the molecular targets for polyphenols effects remain unknown. Meanwhile evidences in the literature have enlightened, not only structural similarities between estrogens and polyphenols known as phytoestrogens, but also in their vascular effects. We hypothesized that alpha isoform of estrogen receptor (ERα) could be involved in the transduction of the vascular benefits of polyphenols. Methodology/Principal Findings Here, we used ERα deficient mice to show that endothelium-dependent vasorelaxation induced either by red wine polyphenol extract, Provinols™, or delphinidin, an anthocyanin that possesses similar pharmacological profile, is mediated by ERα. Indeed, Provinols™, delphinidin and ERα agonists, 17-beta-estradiol and PPT, are able to induce endothelial vasodilatation in aorta from ERα Wild-Type but not from Knock-Out mice, by activation of nitric oxide (NO) pathway in endothelial cells. Besides, silencing the effects of ERα completely prevented the effects of Provinols™ and delphinidin to activate NO pathway (Src, ERK 1/2, eNOS, caveolin-1) leading to NO production. Furthermore, direct interaction between delphinidin and ERα activator site is demonstrated using both binding assay and docking. Most interestingly, the ability of short term oral administration of Provinols™ to decrease response to serotonin and to enhance sensitivity of the endothelium-dependent relaxation to acetylcholine, associated with concomitant increased NO production and decreased superoxide anions, was completely blunted in ERα deficient mice. Conclusions/Significance This study provides evidence that red wine polyphenols, especially delphinidin, exert their endothelial benefits via ERα activation. It is a major breakthrough bringing new insights of the potential therapeutic of polyphenols against cardiovascular pathologies.

Endothelial Dysfunction and Circulating Microparticles from Patients with Obstructive Sleep Apnea

Endothelial dysfunction is involved in vascular complications of obstructive sleep apnea (OSA). In this study, circulating microparticles (MPs) from patients with OSA-induced nocturnal desaturations were characterized and their effects on endothelial function were evaluated. Two age-matched groups of patients undergoing polysomnography for OSA were compared: 35 desaturators with a 3% oxyhemoglobin desaturation index (ODI) > or = 10 events per hour of sleep and 27 nondesaturators with ODI <10 events per hour. MPs were characterized by flow cytometry and then either used to treat in vitro human endothelial cells or to study endothelial function in mice. Circulating MPs did not differ between groups, but MPs from granulocytes and activated leukocytes (CD62L(+)) were found at higher levels in desaturators. In vitro, MPs from desaturators reduced endothelial nitric oxide (NO) production by enhancing phosphorylation of endothelial NO synthase at the site of inhibition and expression of caveolin-1. CD62L(+) MPs positively correlated with ODI. Endothelial NO production negatively correlated with both CD62L(+) MPs and ODI. MPs from desaturators increased expression of endothelial adhesion molecules including E-selectin, ICAM-1 and ITGA5, and cyclooxygenase 2. Moreover, injection of MPs from desaturators into mice impaired endothelium-dependent relaxation in aorta and flow-induced dilation in small mesenteric arteries. This study demonstrates an association between endothelial dysfunction and increased circulating levels of CD62L(+) MPs. This may initiate atherogenic processes in patients with OSA and severe nighttime hypoxia.

Upregulation of Proinflammatory Proteins Through NF-κB Pathway by Shed Membrane Microparticles Results in Vascular Hyporeactivity

Objective—Microparticles are membrane vesicles with procoagulant and proinflammatory properties released during cell activation, including apoptosis. The present study was designed in dissecting the effects evoked by microparticles on vascular reactivity. Methods and Results—Microparticles from either apoptotic T lymphocytic cells or from plasma of diabetic patients with vascular complications induced vascular hyporeactivity in response to vasoconstrictor agents in mouse aorta. Hyporeactivity was reversed by nitric oxide (NO) synthase plus cyclooxygenase-2 inhibitors, and associated with an increased production of vasodilatory products such as NO and prostacyclin. Microparticles induced an upregulation of proinflammatory protein expressions, inducible NO-synthase and cyclooxygenase-2, mainly in the medial layer of the vessels as evidenced by immunochemical staining. In addition, microparticles evoke NF-&kgr;B activation probably through the interaction with the Fas/Fas Ligand pathway. Finally, in vivo treatment of mice with lymphocyte-derived MPs induces vascular hyporeactivity, which was reversed by the combination of NO and cyclooxygenase-2 inhibitors. Conclusion—These data provide a rationale to explain the paracrine role of microparticles as vectors of transcellular exchange of message in promoting vascular dysfunction during inflammatory diseases.

Involvement of beta 3-adrenoceptor in altered beta-adrenergic response in senescent heart: role of nitric oxide synthase 1-derived nitric oxide.

Background:In senescent heart, β-adrenergic response is altered in parallel with β1- and β2-adrenoceptor down-regulation. A negative inotropic effect of β3-adrenoceptor could be involved. In this study, the authors tested the hypothesis that β3-adrenoceptor plays a role in β-adrenergic dysfunction in senescent heart. Methods:β-Adrenergic responses were investigated in vivo (echocardiography–dobutamine, electron paramagnetic resonance) and in vitro (isolated left ventricular papillary muscle, electron paramagnetic resonance) in young adult (3-month-old) and senescent (24-month-old) rats. Nitric oxide synthase (NOS) immunolabeling (confocal microscopy), nitric oxide production (electron paramagnetic resonance) and β-adrenoceptor Western blots were performed in vitro. Data are mean percentages of baseline ± SD. Results:An impaired positive inotropic effect (isoproterenol) was confirmed in senescent hearts in vivo (117 ± 23 vs. 162 ± 16%; P < 0.05) and in vitro (127 ± 10 vs. 179 ± 15%; P < 0.05). In the young adult group, the positive inotropic effect was not significantly modified by the nonselective NOS inhibitor NG-nitro-l-arginine methylester (l-NAME; 183 ± 19%), the selective NOS1 inhibitor vinyl-l-N-5(1-imino-3-butenyl)-l-ornithine (l-VNIO; 172 ± 13%), or the selective NOS2 inhibitor 1400W (183 ± 19%). In the senescent group, in parallel with β3-adrenoceptor up-regulation and increased nitric oxide production, the positive inotropic effect was partially restored by l-NAME (151 ± 8%; P < 0.05) and l-VNIO (149 ± 7%; P < 0.05) but not by 1400W (132 ± 11%; not significant). The positive inotropic effect induced by dibutyryl-cyclic adenosine monophosphate was decreased in the senescent group with the specific β3-adrenoceptor agonist BRL 37344 (167 ± 10 vs. 142 ± 10%; P < 0.05). NOS1 and NOS2 were significantly up-regulated in the senescent rat. Conclusions:In senescent cardiomyopathy, β3-adrenoceptor overexpression plays an important role in the altered β-adrenergic response via induction of NOS1-nitric oxide.

Human serum albumin improves endothelial dysfunction and survival during experimental endotoxemia: Concentration- dependent properties*

Objectives: The mechanisms by which human serum albumin might protect against sepsis-induced organ dysfunction and improve survival are not elucidated. The present study was designed to assess the effects of two concentrations of human serum albumin on endotoxin-induced mortality as well as on endothelial and organ dysfunctions in both mouse and cell models. Design: Prospective, randomized, controlled experimental study. Setting: University research laboratories. Subjects: Swiss mice (n = 10–15/group) were injected with either lipopolysaccharide or vehicle. Four and 12 hrs later, mice were infused or not with human serum albumin HSA (4% or 20%, 10 mL/kg) or normal saline (0.9% NaCl, 30 mL/kg). Human uterine vein endothelial cells were exposed to both lipopolysaccharide and tumor necrosis factor-&agr; during 8 hrs in the presence or absence of human serum albumin (4% or 20%). Measurements and Main Results: Mice survival, reactivity of mesenteric arteries, and Western blot protein analysis were assessed. Circulating endothelin-1, gluthatione, gluthatione disulfide, and creatinine plasma levels were measured. Nitric oxide production, oxidative, and nitrosative stresses were also measured in situ in endothelial cells. Human serum albumin 4%, but not human serum albumin 20% or normal saline solution, improved survival time of endotoxemic mice. Furthermore, human serum albumin 4% activated endothelial nitric oxide synthase and restored lipopolysaccharide-impaired flow-dependent endothelial dilation in mesenteric arteries. This was associated with a downregulation of nuclear factor &kgr;B and an upregulation of nuclear respiratory factor-2 and heme oxygenase-1. Human serum albumin 4% reduced lipopolysaccharide-induced renal dysfunction, enhanced endothelin-1 production and glutathione plasmatic levels, whereas human serum albumin 20% increased gluthatione disulfide. Furthermore, human serum albumin 4% but not 20% blunted lipopolysaccharide-tumor necrosis factor-&agr;-induced oxidative and nitrosative stresses in endothelial cells and increased their gluthatione levels. Conclusions: The present data confirm a protective effect of 4% human serum albumin treatment both on mice survival and endothelial dysfunction by inhibiting inflammatory and oxidative stress pathways induced by endotoxins. Conversely, higher concentrations of human serum albumin were detrimental suggesting a dose-dependent effect.

Circulating Microparticles from Crohn’s Disease Patients Cause Endothelial and Vascular Dysfunctions

Background Microparticles (MPs) are small vesicles released during cell activation or apoptosis. They are involved in coagulation, inflammation and vascular dysfunction in several diseases. We characterized circulating MPs from Crohn’s Disease (CD) patients and evaluated their effects on endothelial function and vascular reactivity after in vivo injection into mice. Methods Circulating MPs and their cellular origins were examined by flow cytometry from blood samples from healthy subjects (HS) and inactive or active CD patients. MPs were intravenously injected into mice. After 24 hours, endothelial function and vascular reactivity were assessed. Results Circulating MP levels did not differ between HS and inactive CD patients except for an increase in leukocyte-derived MPs in CD. Active CD patients compared to HS displayed increased total circulating MPs, pro-coagulant MPs and those from platelets, endothelium, erythrocytes, leukocytes, activated leukocytes and activated platelets. A significant correlation was found between total levels of MPs, those from platelets and endothelial cells, and the Harvey-Bradshaw clinical activity index. MPs from CD, but not from HS, impaired endothelium-dependent relaxation in mice aorta and flow-induced dilation in mice small mesenteric arteries, MPs from inactive CD patients being more effective than those from active patients. CDMPs induced vascular hypo-reactivity in aorta that was prevented by a nitric oxide (NO)-synthase inhibitor, and was associated with a subtle alteration of the balance between NO, reactive oxygen species and the release of COX metabolites. Conclusions We provide evidence that MPs from CD patients significantly alter endothelial and vascular function and therefore, may play a role in CD pathophysiology, at least by contributing to uncontrolled vascular-dependent intestinal damage.

Sexual Dimorphism of Adipose and Hepatic Aquaglyceroporins in Health and Metabolic Disorders

Gender differences in the relative risk of developing metabolic complications, such as insulin resistance or non-alcoholic fatty liver disease (NAFLD), have been reported. The deregulation of glycerol metabolism partly contributes to the onset of these metabolic diseases, since glycerol constitutes a key substrate for the synthesis of triacylglycerols (TAGs) as well as for hepatic gluconeogenesis. The present mini-review covers the sex-related differences in glycerol metabolism and aquaglyceroporins (AQPs) and its impact in the control of adipose and hepatic fat accumulation as well as in whole-body glucose homeostasis. Plasma glycerol concentrations are increased in women compared to men probably due to the higher lipolytic rate and larger AQP7 amounts in visceral fat as well as the well-known sexual dimorphism in fat mass with women showing higher adiposity. AQP9 represents the primary route for glycerol uptake in hepatocytes, where glycerol is converted by the glycerol-kinase enzyme into glycerol-3-phosphate, a key substrate for de novo synthesis of glucose and TAG. In spite of showing similar hepatic AQP9 protein, women exhibit lower hepatocyte glycerol permeability than men, which might contribute to their lower prevalence of insulin resistance and NAFLD.

Rosiglitazone, a Peroxisome Proliferator-Activated Receptor-γ Agonist, Prevents Microparticle-Induced Vascular Hyporeactivity through the Regulation of Proinflammatory Proteins

Microparticles are plasma membrane vesicles with procoagulant and proinflammatory properties. We recently demonstrated that microparticles induce vascular hyporeactivity and evoke up-regulation of proinflammatory protein expression. This study dissected the effect of either in vitro treatment or short-term oral administration of the peroxisome proliferator-activated receptor-γ (PPARγ) agonist, rosiglitazone, on microparticle-induced vascular hyporeactivity of mouse vessels. Microparticles were produced from T cells by actinomycin D treatment. The effects of rosiglitazone on mouse aortic rings incubated with microparticles were investigated. Aortae treated in vitro with rosiglitazone or aortae taken from mice treated by oral administration of the same agonist completely prevented microparticle-induced vascular hyporeactivity in response to U46619 [9,11-dideoxy-11α, 9α-epoxymethanoprostaglandin F2α). These effects of rosiglitazone occurred independently of the presence of endothelium without modifications in blood parameters. The mechanisms involved abrogation of nitric oxide (NO) and prostacyclin overproduction linked to up-regulation of inducible NO-synthase and cyclooxygenase 2 elicited by microparticles. In addition, rosiglitazone treatment reduced the ability of microparticles to evoke increases in interleukin (IL)-6, IL-8, and nuclear factor (NF)-κB transcription, and NF-κB expression and activation. These results suggest that rosiglitazone, via PPARγ activation, counteracts vascular dysfunction associated with increased release of proinflammatory proteins elicited by microparticles. They underscore therapeutic perspective for rosiglitazone in vascular diseases involving enhanced participation of microparticles.