endothelin-1 and 3-nitrotyrosine

Patients with heart disease are frequently treated with supplemental oxygen. Although oxygen can exhibit vasoactive properties in many vascular beds, its effects on the coronary circulation have not been fully characterized. To examine whether supplemental oxygen administration affects coronary blood flow (CBF) in a clinical setting, we measured in 18 patients with stable coronary heart disease the effects of breathing 100% oxygen by face mask for 15 min on CBF (via coronary Doppler flow wire), conduit coronary diameter, CBF response to intracoronary infusion of the endothelium-dependent dilator ACh and to the endothelium-independent dilator adenosine, as well as arterial and coronary venous concentrations of the nitric oxide (NO) metabolites nitrotyrosine, NO(2)(-), and NO(3)(-). Relative to breathing room air, breathing of 100% oxygen increased coronary resistance by approximately 40%, decreased CBF by approximately 30%, increased the appearance of nitrotyrosine in coronary venous plasma, and significantly blunted the CBF response to ACh. Oxygen breathing elicited these changes without affecting the diameter of large-conduit coronary arteries, coronary venous concentrations of NO(2)(-) and NO(3)(-), or the coronary vasodilator response to adenosine. Administering supplemental oxygen to patients undergoing cardiac catheterization substantially increases coronary vascular resistance by a mechanism that may involve oxidative quenching of NO within the coronary microcirculation.

Topics: Acetylcholine; Adenosine; Adult; Aged; Cardiac Catheterization; Coronary Circulation; Coronary Disease; Drug Interactions; Endothelin-1; Female; Humans; Male; Middle Aged; Nitrates; Nitric Oxide; Nitrites; Oxygen; Tyrosine; Vasodilator Agents

Vascular endothelial growth factor pathway inhibitors (VEGFi), used as anti-angiogenic drugs to treat cancer are associated with cardiovascular toxicities through unknown molecular mechanisms. Endothelial cell-derived microparticles (ECMPs) are biomarkers of endothelial injury and are also functionally active since they influence downstream target cell signalling and function. We questioned whether microparticle (MP) status is altered in cancer patients treated with VEGFi and whether they influence endothelial cell function associated with vascular dysfunction. Plasma MPs were isolated from cancer patients before and after treatment with VEGFi (pazopanib, sunitinib, or sorafenib). Human aortic endothelial cells (HAECs) were stimulated with isolated MPs (106 MPs/mL). Microparticle characterization was assessed by flow cytometry. Patients treated with VEGFi had significantly increased levels of plasma ECMP. Endothelial cells exposed to post-VEGFi treatment ECMPs induced an increase in pre-pro-ET-1 mRNA expression, corroborating the increase in endothelin-1 (ET-1) production in HAEC stimulated with vatalanib (VEGFi). Post-VEGFi treatment MPs increased generation of reactive oxygen species in HAEC, effects attenuated by ETA (BQ123) and ETB (BQ788) receptor blockers. VEGFi post-treatment MPs also increased phosphorylation of the inhibitory site of endothelial nitric oxide synthase (eNOS), decreased nitric oxide (NO), and increased ONOO- levels in HAEC, responses inhibited by ETB receptor blockade. Additionally, gene expression of proinflammatory mediators was increased in HAEC exposed to post-treatment MPs, effects inhibited by BQ123 and BQ788. Our findings define novel molecular mechanism involving interplay between microparticles, the ET-1 system and endothelial cell pro-inflammatory and redox signalling, which may be important in cardiovascular toxicity and hypertension associated with VEGFi anti-cancer treatment. New and noteworthy: our novel data identify MPs as biomarkers of VEGFi-induced endothelial injury and important mediators of ET-1-sensitive redox-regulated pro-inflammatory signalling in effector endothelial cells, processes that may contribute to cardiovascular toxicity in VEGFi-treated cancer patients.

Topics: Adult; Aged; Aged, 80 and over; Angiogenesis Inhibitors; Cardiotoxicity; Cell Communication; Cell-Derived Microparticles; Cells, Cultured; Endothelial Cells; Endothelin-1; Female; Humans; Male; Middle Aged; Neoplasms; Nitric Oxide; Reactive Oxygen Species; Signal Transduction; Tyrosine; Vascular Endothelial Growth Factor A

The influence of low-energy defibrillation on changes in the ET-1 levels in the myocardium and on disruptions in coronary blood flow and microcirculation being their consequence still remains unclear. Myocardial microcirculatory dysfunction is considered as a significant cause underlying myocardial dysfunction in post-cardiac arrest syndrome. This study is aimed at evaluating time-dependent changes in ET-1 levels in serum and the heart of a healthy rabbit following the application of a low-energy two-phase shock impulse. The research was conducted in 35 healthy rabbits at the age of 36 - 42 weeks and with body mass from 3200 to 4150 grams. The animals were divided in a randomized way into four groups depending on the dose of the electrical energy planned for the application during the experiment. The life parameters of the animals were monitored with the application of BeneView T5 patient monitor. The concentration of endothelin-1 in the groups was measured before, 15 and 360 minutes after the application of the low-energy double-phase straight-lined electrical impulse. A transthoracic low-energy defibrillation shock impulse causes a long-term increase in the endothelin-1 levels in the heart muscle and blood serum in a healthy rabbit. The increase in ET-1 levels results from the effect of electrical energy, independently of consequences of the ischemia/reperfusion injury. The increase in the endothelin-1 levels may lead to capillary blood flow abnormalities in the heart, contributing to the development of its dysfunction in the course of postresuscitation disease.

Topics: Animals; Blood Pressure; Electric Stimulation; Endothelin-1; Fatty Acid-Binding Proteins; Female; Heart Ventricles; Male; Myocardium; Rabbits; Tyrosine; Ventricular Function

Heart failure and related cardiac complications remains a great health challenge. We investigated the effects of upregulating heme-oxygenase (HO) on myocardial histo-pathological lesions, proinflammatory cytokines/chemokines, oxidative mediators and important markers of heart failure such as osteopontin and osteoprotergerin in N(ω)-nitro-l-arginine methyl ester (L-NAME)-induced hypertension. Treatment with the HO-inducer, heme-arginate improved myocardial morphology in L-NAME hypertensive rats by attenuating subendocardial injury, interstitial fibrosis, mononuclear-cell infiltration and cardiomyocyte hypertrophy. These were associated with the reduction of several inflammatory/oxidative mediators including chemokines/cytokines such as macrophage inflammatory protein-1 alpha (MIP-1α), macrophage chemoattractant protein-1 (MCP-1), tumor necrosis factor alpha (TNF-α), interleukin (IL)-6, IL-1β, endothelin-1, 8-isoprostane, nitrotyrosine, and aldosterone. Similarly, heme-arginate abated the elevated levels of extracellular matrix/remodeling proteins including transforming-growth factor beta (TGF-β1) and collagen-IV in the myocardium. These were accompanied by significant reduction of proteins of heart failure such as osteopontin and osteoprotegerin. Interestingly, the cardio-protective effects of heme-arginate were associated with the potentiation of adiponectin, atrial-natriuretic peptide (ANP), HO-1, HO-activity, cyclic gnanosine monophosphate (cGMP) and the total-anti-oxidant capacity, whereas the HO-inhibitor, chromium-mesoporphyrin nullified the effects of heme-arginate, exacerbating inflammatory injury and oxidative insults. We conclude that heme-arginate therapy protects myocardial damage by potentiating the HO-adiponectin-ANP axis, which in turn suppressed the elevated levels of aldosterone, pro-inflammatory chemokines/cytokines, mononuclear-cell infiltration and oxidative stress, with concomitant reduction of extracellular matrix/remodeling proteins and heart failure proteins. These data suggest a cardio-protective role of the HO system against L-NAME-induced hypertension that could be explored in the design of novel strategies against cardiomyopathy.

Topics: Adiponectin; Aldosterone; Animals; Antioxidants; Arginine; Atrial Natriuretic Factor; Biomarkers; Blood Pressure; Cardiomyopathies; Cardiotonic Agents; Chemokine CCL2; Chemokine CCL3; Cyclic GMP; Dinoprost; Endothelin-1; Enzyme Induction; Extracellular Matrix Proteins; Heart Failure; Heme; Heme Oxygenase (Decyclizing); Hypertension; Interleukin-1beta; Interleukin-6; Male; NG-Nitroarginine Methyl Ester; Rats; Rats, Sprague-Dawley; Tumor Necrosis Factor-alpha; Tyrosine

We investigated the effects of treatment with tempol (an antioxidant) on vascular and metabolic dysfunction induced by a high-fat high-sucrose (HFHS) diet. Rats were randomized to receive an HFHS or chow diet with or without tempol treatment (1.5 mmol·(kg body mass)(-1)·day(-1)) for 4 weeks. Blood pressure, heart rate, and blood flow were measured in the rats by using intravascular catheters and Doppler flow probes. Insulin sensitivity and vascular responses to insulin were assessed during a euglycemic-hyperinsulinemic clamp. In-vitro studies were performed to evaluate vascular reactivity and endothelial and inducible nitric oxide synthase (eNOS; iNOS) expression in vascular and muscle tissues. Endothelin, nitrotyrosine, and NAD(P)H oxidase expressions were determined in vascular tissues, and glucose transport activity and glucose transporter 4 (GLUT4) expression were examined in muscles. Tempol treatment was found to prevent alterations in insulin sensitivity, glucose transport activity, GLUT4 expression, and vascular reactivity, and to prevent increases in plasma insulin, blood pressure, and heart rate noted in the untreated HFHS-fed rats. These were associated with increased levels of eNOS expression in vascular and muscle tissues, but reductions in nitrotyrosine, endothelin, NAD(P)H oxidase, and iNOS expressions. Therefore, oxidative stress induced by a relatively short-term HFHS diet could contribute to the early development of vascular and metabolic abnormalities in rats.

Topics: Animals; Aorta, Thoracic; Blood Pressure; Body Mass Index; Cyclic N-Oxides; Diet, High-Fat; Dietary Sucrose; Endothelin-1; Endothelins; Endothelium, Vascular; Glucose; Glucose Transporter Type 4; Heart Rate; Hemodynamics; Inflammation; Insulin; Insulin Resistance; Male; Muscle, Skeletal; NADPH Oxidases; Nitric Oxide Synthase Type II; Nitric Oxide Synthase Type III; Oxidative Stress; Random Allocation; Rats; Rats, Sprague-Dawley; Regional Blood Flow; Spin Labels; Tyrosine

Chronic liver diseases are commonly associated with tissue hypoxia that may cause inflammation, oxidative stress, liver cell injury and increased nuclear transcriptional regulation. The hepatic response to chronic hypoxia at the molecular level has not yet been clearly understood until now. The aim of this study is to investigate whether nuclear transcription factors [hypoxia-inducible factor-1 (HIF-1α), activator protein-1 (AP-1), nuclear factor-kappa B (NF-κB)] exhibit activity changes during hepatic response to chronic hypoxia. Blood and liver samples were collected from adult Sprague-Dawley rats living in atmospheric air or 10% oxygen for four weeks. Levels of serum alanine aminotransferase (ALT), 8-isoprostane and nitrotyrosine were measured. The activities of nuclear transcription factors and the expression of downstream genes (iNOS, eNOS, ET-1 and VEGF) were measured using RT-PCR, Western blotting and Gel shift analysis. Results showed that serum ALT level, 8-isoprostane level and formation of nitrotyrosine were within normal range at all time-points. In the hypoxic liver, DNA-binding activities of HIF-1α, NF-κB and AP-1 increased significantly. Expression levels of iNOS, VEGF and ET-1 progressively increased from day 7 to day 28. eNOS was also elevated in the hypoxic liver. In conclusion, our study suggests that increased activity of HIF-1α, AP-1 and NF-κB may partly play a significant role in the hepatic response to oxidative stress and liver injury under chronic hypoxia. The increased expression of VEGF, ET-1, iNOS and eNOS may be partly due to the compensatory mechanism in the vascular beds of the liver in response to chronic hypoxia.

Topics: Alanine Transaminase; Animals; Biomarkers; Blotting, Western; Chronic Disease; Dinoprost; Disease Models, Animal; Electrophoretic Mobility Shift Assay; Endothelin-1; Gene Expression Regulation; Hypoxia; Hypoxia-Inducible Factor 1, alpha Subunit; Liver; Male; NF-kappa B; Nitric Oxide Synthase Type II; Nitric Oxide Synthase Type III; Oxidative Stress; Rats; Rats, Sprague-Dawley; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Time Factors; Transcription Factor AP-1; Tyrosine; Vascular Endothelial Growth Factor A

NCX 434 is a nitric oxide (NO)-donating triamcinolone acetonide (TA), shown to enhance optic nerve head (ONH) oxygen saturation in non-human primate eyes. Here, the effects of a single intravitreal (IVT) injection of TA were compared with those of NCX 434 on intraocular pressure (IOP), retinal function and retrobulbar haemodymamics in endothelin-1 (ET-1) induced ONH ischaemia/reperfusion in rabbits. Biochemical changes were also assessed in the aqueous humour and in retinal biopsies.. IOP and resistivity index of ophthalmic artery (RI-OA) were recorded using TonoPen and ecocolor Doppler, respectively. Retinal function was assessed using photopic electroretinography. Cytokine expression and oxidative stress markers were evaluated with immunoassay techniques.. At 4 weeks post IVT treatment, TA increased IOP and RI-OA while NCX 434 did not (IOP(Vehicle)=13.6±1.3, IOP(NCX 434)=16.9±2.2, IOP(TA)=20.9±1.9 mm Hg; p<0.05 vs vehicle; RI-OA(Vehicle)=0.44±0.03; RI-OA(NCX 434)=0.47±0.02; RI-OA(TA)=0.60±0.04). Both NCX 434 and TA reversed ET-1 induced decrease in electroretinography amplitude to similar extents. NCX 434 attenuated ET-1 induced oxidative stress markers and nitrotyrosine in retinal tissue, and interleukin-6 and tumour necrosis factor-α in aqueous humour more effectively than TA.. NCX 434 attenuates ET-1 induced ischaemia/reperfusion damage without increasing IOP, probably due to NO release. If data are confirmed in other species and models, this compound could represent an interesting new therapeutic option for retinal and ONH diseases, including diabetic retinopathy.

Topics: Animals; Caspase 3; Cytokines; Electroretinography; Endothelin-1; Glutathione; Hemodynamics; Intraocular Pressure; Intravitreal Injections; Laser-Doppler Flowmetry; Male; Nitrates; Nitric Oxide Donors; Ophthalmic Artery; Optic Disk; Rabbits; Reperfusion Injury; Retina; Retinal Diseases; Superoxide Dismutase; Tonometry, Ocular; Triamcinolone Acetonide; Tyrosine

Diabetes mellitus is the leading cause of vascular complications such as atherosclerosis. This study was designed to investigate whether Prunella vulgaris (APV) would inhibit diabetic atherosclerosis in db/db mice with type 2 diabetes. The db/db mice were treated with high fat/high cholesterol (HFHC) diet and an aqueous extract of APV (100 and 200 mg/kg/day) for eight weeks to examine the long-term effect on metabolic abnormalities and diabetic atherosclerosis. APV treatment markedly lowered blood glucose and systolic blood pressure. The db/db mice experienced an increase in blood urea nitrogen as well as a decrease of creatinine clearance, the latter of which was restored by treatment with APV. Treatment with APV markedly decreased total plasma cholesterol, triglyceride, and LDL-cholesterol and also increased the HDL-cholesterol. In addition, malondialdehyde and TGF-β1 were decreased by treatment of APV. On the other hand, total NO level was decreased in db/db mice. However, the NO level was increased by treatment with APV, suggesting an association with vascular dysfunction. Vascular relaxation of aortic rings by acetylcholine or SNP-inducement was ameliorated by APV in a dose-dependent manner. Damage of vascular intima and hypertrophic of media were observed in db/db mice; however its dysfunction was improved by the treatment of APV. APV treatment significantly reduced the aortic expressions of ICAM-1, VCAM-1, ET-1, and nitrotyrosine. Furthermore, expression of eNOS in aortic was remarkably increased by APV treatment. Taken together, APV suppressed hyperglycemia and diabetic vascular dysfunction in HFHC diet-db/db mice. The present data suggest that Prunella vulgaris may prevent development of diabetic atherosclerosis.

Topics: Acetylcholine; Animals; Aorta; Atherosclerosis; Blood Glucose; Blood Pressure; Blood Urea Nitrogen; Cholesterol, Dietary; Creatinine; Diabetes Complications; Diabetes Mellitus, Type 2; Diet, High-Fat; Dose-Response Relationship, Drug; Endothelin-1; Hyperglycemia; Hypertrophy; Hypoglycemic Agents; Intercellular Adhesion Molecule-1; Lipids; Male; Malondialdehyde; Mice; Mice, Inbred Strains; Mice, Knockout; Nitric Oxide; Phytotherapy; Plant Extracts; Prunella; Transforming Growth Factor beta1; Tunica Intima; Tunica Media; Tyrosine; Vascular Cell Adhesion Molecule-1; Vasodilation

Diabetic nephropathy is associated with cardiovascular morbidity. Angiotensin-converting enzyme (ACE) inhibitors provide imperfect renoprotection in advanced type 2 diabetes, and cardiovascular risk remains elevated. Endothelin (ET)-1 has a role in renal and cardiac dysfunction in diabetes. Here, we assessed whether combination therapy with an ACE inhibitor and ET(A) receptor antagonist provided reno- and cardioprotection in rats with overt type 2 diabetes. Four groups of Zucker diabetic fatty (ZDF) rats were treated orally from 4 (when proteinuric) to 8 mo with vehicle, ramipril (1 mg/kg), sitaxsentan (60 mg/kg), and ramipril plus sitaxsentan. Lean rats served as controls. Combined therapy ameliorated proteinuria and glomerulosclerosis mostly as a result of the action of ramipril. Simultaneous blockade of ANG II and ET-1 pathways normalized renal monocyte chemoattractant protein-1 and interstitial inflammation. Cardiomyocyte loss, volume enlargement, and capillary rarefaction were prominent abnormalities of ZDF myocardium. Myocyte volume was reduced by ramipril and sitaxsentan, which also ameliorated heart capillary density. Drug combination restored myocardial structure and reestablished an adequate capillary network in the presence of increased cardiac expression of VEGF/VEGFR-1, and significant reduction of oxidative stress. In conclusion, in type 2 diabetes concomitant blockade of ANG II synthesis and ET-1 biological activity through an ET(A) receptor antagonist led to substantial albeit not complete renoprotection, almost due to the ACE inhibitor. The drug combination also showed cardioprotective properties, which however, were mainly dependent on the contribution of the ET(A) receptor antagonist through the action of VEGF.

Topics: Angiotensin-Converting Enzyme Inhibitors; Animals; Blood Glucose; Body Weight; Cell Count; Collagen Type III; Diabetes Mellitus, Type 2; Endothelin A Receptor Antagonists; Endothelin-1; Heart; Hemodynamics; Immunohistochemistry; Kidney; Kidney Function Tests; Male; Muscle Cells; Myocardium; Rats; Rats, Zucker; Real-Time Polymerase Chain Reaction; Receptors, Vascular Endothelial Growth Factor; Survival; Tyrosine; Vascular Endothelial Growth Factor A

Endothelin-1 (ET-1) is up-regulated in the endothelial cells and astrocytes under ischemia. Transgenic mice with astrocytic ET-1 over-expression (GET-1) showed more severe neurological deficit and larger infarct after transient middle cerebral artery occlusion (MCAO). Here, the significance of endothelial ET-1 in ischemic brain injury was investigated using transgenic mice with the endothelial ET-1 over-expression (TET-1). Increased ET-1 level was observed in the TET-1 brain infarct core after transient MCAO. ET(A) receptor expression was induced in the penumbra and ET(A) antagonist (A-147627) partially normalized the infarct volume and neurological deficit. In the infarct core of TET-1 brain, superoxide, nitrotyrosine, and gp91(phox) levels were increased. TET-1 brain displayed increased matrix metalloproteinase-2 expression, water content, immunoglobulin leakage and decreased occludin level in the ipsilateral hemisphere indicative of BBB breakdown and hemispheric edema. Interestingly, AQP-4 expression was increased in the penumbra of TET-1 brain following transient MCAO leading to the water accumulation. Taken together, endothelial ET-1 over-expression and ETA receptor activation contributes to the increased oxidative stress, water accumulation and BBB breakdown after transient MCAO leading to more severe neurological deficit and increased infarct.

Topics: Animals; Aquaporin 4; Atrasentan; Blood-Brain Barrier; Brain; Capillary Permeability; Endothelin A Receptor Antagonists; Endothelin-1; Endothelium, Vascular; Immunoglobulins; Infarction, Middle Cerebral Artery; Matrix Metalloproteinase 2; Membrane Glycoproteins; Membrane Proteins; Mice; Mice, Transgenic; NADPH Oxidase 2; NADPH Oxidases; Occludin; Oxidative Stress; Promoter Regions, Genetic; Pyrrolidines; Receptor, Endothelin A; Receptor, TIE-1; Superoxides; Tyrosine; Water

This study was designed to examine the effects of a high-fat, high-sucrose (HFHS) diet on vascular and metabolic actions of insulin. Male rats were randomized to receive an HFHS or regular chow diet for 4 wk. In a first series of experiments, the rats had pulsed Doppler flow probes and intravascular catheters implanted to measure blood pressure, heart rate, and regional blood flows. Insulin sensitivity and vascular responses to insulin were assessed during a euglycemic hyperinsulinemic clamp performed in conscious rats. In a second series of experiments, new groups of rats were used to examine skeletal muscle glucose transport activity and to determine in vitro vascular reactivity, endothelial nitric oxide synthase (eNOS) protein expression in muscle and vascular tissues and endothelin content, nitrotyrosine formation, and NAD(P)H oxidase protein expression in vascular tissues. The HFHS-fed rats displayed insulin resistance, hyperinsulinemia, hypertriglyceridemia, hyperlipidemia, elevated blood pressure, and impaired insulin-mediated renal and skeletal muscle vasodilator responses. A reduction in endothelium-dependent vasorelaxation, accompanied by a decreased eNOS protein expression in muscles and blood vessel endothelium, and increased vascular endothelin-1 protein content were also noted in HFHS-fed rats compared with control rats. Furthermore, the HFHS diet induced a reduced insulin-stimulated glucose transport activity in muscles and increased levels of NAD(P)H oxidase protein and nitrotyrosine formation in vascular tissues. These findings support the importance of eNOS protein in linking metabolic and vascular disease and indicate the ability of a Westernized diet to induce endothelial dysfunction and to alter metabolic and vascular homeostasis.

Topics: Animals; Blood Pressure; Blotting, Western; Body Weight; Deoxyglucose; Diet; Dietary Fats; Endothelin-1; Endothelium, Vascular; Fatty Acids, Nonesterified; Fluorescent Antibody Technique; Glucose Clamp Technique; Heart Rate; Insulin; Insulin Resistance; Male; Obesity; Organ Size; Rats; Rats, Sprague-Dawley; Sucrose; Triglycerides; Tyrosine; Vascular Diseases; Vascular Resistance

Cardiac inflammation and generation of oxidative stress are known to contribute to doxorubicin (Dox)-induced cardiomyopathy. Toll-like receptors (TLRs) are a part of the innate immune system and are involved in cardiac stress reactions. Since TLR4 might play a relevant role in cardiac inflammatory signalling, we investigated whether or not TLR4 is involved in Dox-induced cardiotoxicity.. Five days after a single injection of Dox (20 mg/kg; i.p.), left ventricular pressure-volume loops were measured in wild-type and TLR4-deficient mice (TLR4-/-) Dox-treated and control mice. Analyses of possible pathophysiological mechanisms were performed in left ventricular tissue and isolated myocytes, respectively. Dox injection resulted in an impairment of left ventricular function and neurohumoral activation, indexed by increased ET-1 expression. This was further associated with an increase in cardiac oxidative stress, inflammation and apoptosis, as indicated by an up-regulation of cardiac lipid peroxidation, TNF-alpha expression and enhanced content of TUNEL-positive cells. In contrast, TLR4-/- Dox mice showed improved left ventricular function with reduced oxidative and inflammatory stress response including reduced cardiac apoptosis. These results were found to be associated with an increase of GATA-4 expression.. TLR4 deficiency improves left ventricular function and attenuates pathophysiological key mechanisms in Dox-induced cardiomyopathy.

Topics: Animals; Antibiotics, Antineoplastic; Doxorubicin; Endothelin-1; GATA4 Transcription Factor; In Situ Nick-End Labeling; Lipid Peroxidation; Mice; Mice, Inbred C57BL; Mice, Knockout; Toll-Like Receptor 4; Tyrosine; Ventricular Dysfunction, Left

Polymorphonuclear leukocytes (PMNs) play an important role during inflammation in cardiovascular diseases. Human neutrophil peptides (HNPs) are released from PMN granules upon activation and are conventionally involved in microbial killing. Recent studies suggested that HNPs may be involved in the pathogenesis of vascular abnormality by modulating inflammatory responses and vascular tone. Since HNPs directly interact with endothelium upon release from PMNs in the circulation, we tested the hypothesis that the stimulation with HNPs of endothelial cells modulates the expression of vasoactive by-products through altering cyclooxygenase (COX) activity. When human umbilical vein endothelial cells were stimulated with purified HNPs, we observed a time- and dose-dependent increase in the expression of COX-2, whereas COX-1 levels remained unchanged. Despite an increased expression of COX-2 at the protein level, HNPs did not significantly enhance the COX-2 activity, thus the production of the prostaglandin PGI2. HNPs significantly induced the release of endothelin-1 (ET-1) as well as the formation of nitrotyrosine. The HNP-induced COX-2 and ET-1 production was attenuated by the treatment with the oxygen free radical scavenger N-acetyl-L-cysteine and the inhibitors of p38 MAPK and NF-kappaB, respectively. The angiontensin II pathway did not seem to be involved in the HNP-induced upregulation of COX-2 and ET-1 since the use of the angiotensin-converting enzyme inhibitor enalapril had no effect in this context. In conclusion, HNP may play an important role in the pathogenesis of inflammatory cardiovascular diseases by activating endothelial cells to produce vasoactive by-products as a result of oxidative stress.

Topics: Angiotensin II; Angiotensin-Converting Enzyme Inhibitors; Cells, Cultured; Cyclooxygenase 1; Cyclooxygenase 2; Endothelial Cells; Endothelin-1; Epoprostenol; Free Radical Scavengers; Humans; Mitogen-Activated Protein Kinase 1; Mitogen-Activated Protein Kinase 3; Neutrophils; NF-kappa B; Oxidative Stress; p38 Mitogen-Activated Protein Kinases; Peptides; Protein Kinase Inhibitors; Time Factors; Tyrosine; Up-Regulation

Oxidative stress is involved in the pathogenesis of diabetes and its cardiovascular complications. Metallothionein (MT), a stress-response protein, is significantly increased in the liver and kidney of diabetic animals. We examined whether diabetes also induces cardiac MT synthesis through oxidative damage and whether MT overexpression protects the heart from injury. Diabetes was induced in mice by single injection of streptozotocin (STZ), and cardiac MT mRNA and protein levels were measured 2 weeks and 2 months after STZ treatment. Diabetes significantly increased cardiac MT synthesis 2 weeks and 2 months after STZ treatment, with no change in cardiac metals including zinc, copper, and iron. Serum and cardiac vasopeptide endothelin and inflammatory cytokine tumor necrosis factor-alpha were also significantly increased in diabetic hearts, as were the ratio of oxidized to reduced glutathione and the immunohistochemical staining of 3-nitrotyrosine and 4-hydroxynonenal. To explore the biological importance of increased MT synthesis in the heart, MT-overexpressing transgenic mice were treated with STZ and then examined 2 months later. A loss of inotropic reserve, uncovered during beta-adrenergic stimulation, and the presence of cardiac fibrosis, shown by increased Sirius red staining of collagen, were evident in the wild-type diabetic mice but not in the MT-overexpressing transgenic diabetic mice. These results suggest that diabetes-induced cardiac MT expression likely associates with systemic increases in endothelin-1 and tumor necrosis factor-alpha and the resulting cardiac oxidative stress. Overexpressing cardiac MT significantly protects the heart from diabetes-induced injury.

Topics: Aldehydes; Animals; Blotting, Northern; Blotting, Western; Cardiovascular Diseases; Copper; Diabetes Mellitus, Experimental; Endothelin-1; Glutathione; Immunohistochemistry; Interleukin-6; Iron; Metallothionein; Mice; Mice, Transgenic; Myocardium; Oxidative Stress; RNA, Messenger; Tumor Necrosis Factor-alpha; Tyrosine; Zinc

Accumulation of interstitial collagen (fibrosis) between the endothelium and myocytes is one of the hallmarks of cardiac failure in renovascular hypertension (RVH). Renal insufficiency increases plasma homocysteine (Hcy), and levels of peroxisome proliferator-activated receptor-gamma (PPAR-gamma) are inversely related to plasma Hcy levels. We hypothesize that in RVH, accumulation of collagen between the endothelium and myocytes leads to endothelial-myocyte disconnection and uncoupling, in part, by hyperhomocysteinemia. Furthermore, we hypothesize that Hcy increases reactive oxygen species, generates nitrotyrosine, activates latent matrix metalloproteinase, and decreases the levels of endothelial nitric oxide in response to antagonizing PPAR-gamma. To create RVH in mice, the left renal artery was clipped with 0.4-mm silver wire for the 2 kidney, 1 clip (2K1C) method. Sham surgery was used as a control. To induce PPAR-gamma, 8 microg/mL ciglitazone (CZ) was administered to drinking water 2 days before surgery and continued for 4 weeks. Mice were grouped as 2K1C, sham, 2K1C+CZ, or sham+CZ (n = 6 in each group). Plasma Hcy increased 2-fold in the 2K1C-treated group (p < 0.05) as compared with the sham, and CZ had no effect on Hcy levels as compared to the 2K1C-treated group. Hcy binding in cardiac tissue homogenates decreased in the 2K1C-treated group but was substantially higher in the CZ-treated group. Cardiac reactive oxygen species levels were increased and endothelial nitric oxide were decreased in the 2K1C-treated group. Matrix metalloproteinase-2 and -9 activities were increased in the 2K1C-treated group compared with the control. Levels of cardiac inhibitor of metalloproteinase were decreased, whereas there was no change in tissue inhibitor of metalloproteinase-1 expression in the 2K1C-treated group vs. the sham-treated group. Collagen and nitrotyrosine levels were increased in the 2K1C-treated group, but mice treated with CZ showed lower levels comparatively. Cardiac transferase deoxyuridine nick-end labeling-positive cells were increased, and muscle cells were impaired in the 2K1C-treated mice vs. the sham-control mice. This was associated with decreased acetylcholine and bradykinin responses, which suggests endothelial-myocyte uncoupling in 2K1C-treated mice. Our results suggest that fibrosis between the endothelium and myocytes leads to an endothelial-myocyte disconnection and uncoupling by Hcy accumulation secondary to increased reactive oxygen s

Topics: Acetylcholine; Animals; Blotting, Western; Collagen; Endothelin-1; Endothelium, Vascular; Fibrosis; Homocysteine; Hypertension, Renovascular; Hypoglycemic Agents; Kidney; Male; Matrix Metalloproteinases; Mice; Mice, Inbred C57BL; Myocardial Contraction; Myocytes, Cardiac; Nitroprusside; PPAR gamma; Proteinuria; Thiazolidinediones; Tissue Inhibitor of Metalloproteinase-1; Tyrosine; Vasodilator Agents; Ventricular Remodeling

Maternal diabetes significantly increases the risk of congenital malformation, a syndrome known as diabetic embryopathy. Nitric oxide (NO), implicated in embryogenesis, has been found elevated in embryos from diabetic rats during organogenesis. The developmental signaling molecules endothelin-1 (ET-1) and 15-deoxy delta(12,14)prostaglandin J2 (15dPGJ2) downregulate embryonic NO levels. In the presence of NO and superoxide, formation of the potent oxidant peroxynitrite may occur. Therefore, we investigated peroxynitrite-induced damage, ET-1 and 15dPGJ2 concentrations, and the capability of ET-1, 15dPGJ2 and prostaglandin E2 (PGE2) to regulate NO production in embryos from severely diabetic rats (streptozotocin-induced before pregnancy). We found intense nitrotyrosine immunostaining (an index of peroxynitrite-induced damage) in neural folds, neural tube and developing heart of embryos from diabetic rats (P < 0.001 vs controls). We also found reduced ET-1 (P < 0.001) and 15dPGJ2 (P < 0.001) concentrations in embryos from diabetic rats when compared with controls. In addition, the inhibitory effect of ET-1, 15dPGJ2 and PGE2 on NO production found in control embryos was not observed in embryos from severely diabetic rats. In conclusion, both the demonstrated peroxynitrite-induced damage and the altered levels and function of multiple signaling molecules involved in the regulation of NO production provide supportive evidence of nitrosative stress in diabetic embryopathy.

Topics: Animals; Diabetes Mellitus, Experimental; Embryo, Mammalian; Endothelin-1; Female; Immunohistochemistry; Nitrates; Nitric Oxide; Nitrites; Organogenesis; Pregnancy; Pregnancy in Diabetics; Prostaglandin D2; Rats; Rats, Wistar; Tyrosine

Phytoestrogens are considered to be natural selective estrogen receptor modulators exerting antioxidant activity and improving vascular function. However, the mechanisms responsible for their antioxidative effects remain largely unknown. This study tested the hypothesis that genistein may provide significant endothelial protection by antioxidative effects through attenuating NADPH oxidase expression and activity. The results showed that genistein suppressed the expressions of the p22phox NADPH oxidase subunit and angiotensin II (Ang II) type 1 (AT1) receptor in a concentration- and time-dependent manner in aortic endothelial cells from stroke-prone spontaneously hypertensive rats examined by Western blot analysis. Treatment with genistein also remarkably reduced the Ang II-induced superoxide by the reduction of nitroblue tetrazolium, inhibited nitrotyrosine formation, and attenuated endothelin-1 production by ELISA via the stimulation of Ang II. However, when cells were pretreated with ICI-182780, an estrogen-receptor antagonist, at a concentration of 50 micromol/l for 30 min and then co-incubated with ICI-182780 and genistein for 24 h, the inhibitory effect of genistein was not blocked. In contrast, the inhibitory effect of genistein treatment was partially reversed by 30-min pretreatment of endothelial cells with GW9662, a peroxisome proliferator-activated receptor gamma (PPARgamma) antagonist. Genistein thus appears to act as an antioxidant at the transcription level by the downregulation of p22phox and AT1 receptor expression. Our data also showed that the PPARgamma pathway was involved, at least in part, in the inhibitory effect of genistein on the expression of p22phox and AT1 receptors. The endothelial-protective effects of phytoestrogen may contribute to improvement of cardiovascular functions.

Topics: Angiotensin II; Anilides; Animals; Aorta, Thoracic; Cells, Cultured; Endothelin-1; Endothelium, Vascular; Enzyme Inhibitors; Estradiol; Estrogen Antagonists; Fulvestrant; Genistein; Hypertension; Male; Membrane Transport Proteins; NADPH Dehydrogenase; NADPH Oxidases; Phosphoproteins; PPAR gamma; Rats; Rats, Inbred SHR; Receptor, Angiotensin, Type 1; Signal Transduction; Stroke; Superoxides; Tyrosine; Vasoconstrictor Agents

Newborn rats exposed to 60% O(2) for 14 d demonstrated a bronchopulmonary dysplasia-like lung morphology and pulmonary hypertension. A 21-aminosteroid antioxidant, U74389G, attenuated both pulmonary hypertension and macrophage accumulation in the O(2)-exposed lungs. To determine whether macrophage accumulation played an essential role in the development of pulmonary hypertension in this model, pups were treated with gadolinium chloride (GdCl(3)) to reduce lung macrophage content. Treatment of 60% O(2)-exposed animals with GdCl(3) prevented right ventricular hypertrophy (p < 0.05) and smooth muscle hyperplasia around pulmonary vessels, but had no effect on morphologic changes in the lung parenchyma. In addition, GdCl(3) inhibited 60% O(2)-mediated increases in endothelin-1, 8-isoprostane, and nitrotyrosine residues. Organotypic cultures of fetal rat distal lung cells were subjected to cyclical mechanical strain to assess the potential role of GdCl(3)-induced blockade of stretch-mediated cation channels in these effects. Mechanical strain caused a moderate increase of endothelin-1 (p < 0.05), which was unaffected by GdCl(3), but had no effect on 8-isoprostane or nitric oxide synthesis. A critical role for endothelin-1 in O(2)-mediated pulmonary hypertension was confirmed using the combined endothelin receptor antagonist SB217242. We concluded that pulmonary macrophage accumulation, in response to 60% O(2), mediated pulmonary hypertension through up-regulation of endothelin-1.

Topics: Animals; Animals, Newborn; Bronchopulmonary Dysplasia; Cell Movement; Cells, Cultured; Dinoprost; Endothelin-1; F2-Isoprostanes; Gadolinium; Humans; Hypertension, Pulmonary; Hypertrophy, Right Ventricular; Infant, Newborn; Macrophages, Alveolar; Oxygen; Rats; Rats, Sprague-Dawley; Tyrosine

Our previous studies have demonstrated that inhaled nitric oxide (NO) decreases nitric oxide synthase (NOS) activity in vivo and that this inhibition is associated with rebound pulmonary hypertension upon acute withdrawal of inhaled NO. We have also demonstrated that inhaled NO elevates plasma endothelin-1 (ET-1) levels and that pretreatment with PD156707, an ETA receptor antagonist, blocks the rebound hypertension. The objectives of this study were to further elucidate the role of ET-1 in the rebound pulmonary hypertension upon acute withdrawal of inhaled NO. Inhaled NO (40 ppm) delivered to thirteen 4-week-old lambs decreased NOS activity by 36.2% in control lambs (P<0.05), whereas NOS activity was preserved in PD156707-treated lambs. When primary cultures of pulmonary artery smooth muscle cells were exposed to ET-1, superoxide production increased by 33% (P<0.05). This increase was blocked by a preincubation with PD156707. Furthermore, cotreatment of cells with ET-1 and NO increased peroxynitrite levels by 26% (P<0.05), whereas preincubation of purified human endothelial nitric oxide synthase (eNOS) protein with peroxynitrite generated a nitrated enzyme with 50% activity relative to control (P<0.05). Western blot analysis of peripheral lung extracts obtained after 24 hours of inhaled NO revealed a 90% reduction in 3-nitrotyrosine residues (P<0.05) in PD156707-treated lambs. The nitration of eNOS was also reduced by 40% in PD156707-treated lambs (P<0.05). These data suggest that the reduction of NOS activity associated with inhaled NO therapy may involve ETA receptor-mediated superoxide production. ETA receptor antagonists may prevent rebound pulmonary hypertension by protecting endogenous eNOS activity during inhaled NO therapy.

Topics: Administration, Inhalation; Animals; Blotting, Western; Cells, Cultured; Dioxoles; Disease Models, Animal; Endothelin Receptor Antagonists; Endothelin-1; Enzyme Activation; Humans; Hypertension, Pulmonary; Lung; Microscopy, Fluorescence; Muscle, Smooth, Vascular; Nitrates; Nitric Oxide; Nitric Oxide Donors; Nitric Oxide Synthase; Nitric Oxide Synthase Type III; Pulmonary Artery; Receptor, Endothelin A; Secondary Prevention; Sheep; Superoxides; Tyrosine