15-hydroxy-11-alpha-9-alpha-(epoxymethano)prosta-5-13-dienoic-acid and 3-nitrotyrosine

Augmented vasoconstrictor reactivity is thought to play an important role in the development of chronic hypoxia (CH)-induced neonatal pulmonary hypertension. However, whether this response to CH results from pulmonary endothelial dysfunction and reduced nitric oxide (NO)-mediated vasodilation is not well understood. We hypothesized that neonatal CH enhances basal tone and pulmonary vasoconstrictor sensitivity by limiting NO-dependent pulmonary vasodilation. To test this hypothesis, we assessed the effects of the NO synthase (NOS) inhibitor

Topics: 15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; Animals; Animals, Newborn; Chronic Disease; Enzyme Inhibitors; Free Radical Scavengers; Hypoxia; Lung; Nitric Oxide; Nitric Oxide Synthase; Nitroarginine; Pulmonary Circulation; Rats; Rats, Sprague-Dawley; Tyrosine; Vascular Resistance; Vasoconstriction; Vasoconstrictor Agents; Vasodilation

We investigated the effects of cardiopulmonary bypass (CPB) on peripheral arteriolar reactivity and associated signaling pathways in poorly controlled (UDM), controlled (CDM), and case-matched nondiabetic (ND) patients undergoing coronary artery bypass grafting (CABG).. Skeletal muscle arterioles were harvested before and after CPB from the UDM patients (hemoglobin A1c [HbA1c]=9.0 ± 0.3), the CDM patients (HbA1c=6.3 ± 0.15), and the ND patients (HbA1c=5.2 ± 0.1) undergoing CABG surgery (n=10/group). In vitro relaxation responses of precontracted arterioles to endothelium-dependent vasodilators adenosine 5'-diphosphate (ADP) and substance P and the endothelium-independent vasodilator sodium nitroprusside (SNP) were examined. The baseline responses to ADP, substance P, and SNP of arterioles from the UDM patients were decreased as compared with microvessels from the ND or CDM patients (P<0.05). The post-CPB relaxation responses to ADP and substance P were significantly decreased in all 3 groups compared with pre-CPB responses (P<0.05). However, these decreases were more pronounced in the UDM group (P<0.05). The post-CPB response to SNP was significantly decreased only in the UDM group, not in the other 2 groups compared with pre-CPB. The expression of protein kinase C (PKC)-α, PKC-β, protein oxidation, and nitrotyrosine in the skeletal muscle were significantly increased in the UDM group as compared with those of ND or CDM groups (P<0.05).. Poorly controlled diabetes results in impaired arteriolar function before and after CPB. These alterations are associated with the increased expression/activation of PKC-α and PKC-β and enhanced oxidative and nitrosative stress.

Topics: 15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; Adenosine Diphosphate; Aged; Arterioles; Cardiopulmonary Bypass; Coronary Artery Bypass; Cyclic AMP-Dependent Protein Kinases; Diabetes Mellitus, Type 2; Disease Susceptibility; Endothelium, Vascular; Enzyme Induction; Female; Gene Expression Regulation; Glycated Hemoglobin; Humans; Hypoglycemic Agents; Inflammation; Male; Microcirculation; Middle Aged; Muscle, Skeletal; Nitroprusside; Phosphorylation; Protein Processing, Post-Translational; Proto-Oncogene Proteins c-akt; Substance P; Tyrosine; Vasoconstriction; Vasodilator Agents

The thromboxane receptor (TPr) and multiple TPr ligands, including thromboxane A(2) (TxA(2)) and prostaglandin H(2), are elevated during vascular and atherothrombotic diseases. How TPr stimulation causes vascular injury remains poorly defined. This study was conducted to investigate the mechanism by which TPr stimulation leads to vascular injury.. Exposure of bovine aortic endothelial cells to either [1S-(1α,2β(5Z),3α(1E,3R),4α]-7-[3-(3-hydroxy-4-(d'-iodophenoxy)-1-butenyl)-7-oxabicyclo-[2.2.1] heptan-2-yl]-5'-heptenoic acid (IBOP) or U46619, 2 structurally related TxA(2) mimetics, for 24 hours markedly increased the release of superoxide anions (O(2)(·-)) and peroxynitrite (ONOO(-)) but reduced cyclic GMP, an index of nitric oxide bioactivity. IBOP also significantly suppressed activity of endothelial nitric oxide synthase (eNOS), increased enzyme-inactive eNOS monomers, and reduced levels of tetrahydrobiopterin, an essential eNOS cofactor. IBOP- and U46619-induced increases in O(2)(·-) were accompanied by the membrane translocation of the p67(phox) subunit of NAD(P)H oxidase. Pharmacological or genetic inhibition of either NAD(P)H oxidase or TPr abolished IBOP-induced O(2)(·-) formation. Furthermore, TPr activation significantly increased protein kinase C-ζ (PKC-ζ) in membrane fractions and PKC-ζ phosphorylation at Thr410. Consistently, PKC-ζ inhibition abolished TPr activation-induced membrane translocation of p67(phox) and O(2)(·-) production. Finally, exposure of isolated mouse aortae to IBOP markedly increased O(2)(·-) in wild-type but not in those from gp91(phox) knockout mice.. We conclude that TPr activation via PKC-ζ-mediated NAD(P)H oxidase activation increases both O(2)(·-) and ONOO(-), resulting in eNOS uncoupling in endothelial cells.

Topics: 15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; Animals; Apoptosis; Biopterins; Bridged Bicyclo Compounds, Heterocyclic; Cattle; Cell Survival; Cells, Cultured; Cyclic GMP; Cytochrome P-450 Enzyme System; Endothelial Cells; Enzyme Activation; Enzyme Inhibitors; Fatty Acids, Unsaturated; Intramolecular Oxidoreductases; Mice; Mice, Inbred C57BL; Mice, Knockout; NADPH Oxidases; Nitric Oxide; Nitric Oxide Synthase Type III; Oxidative Stress; Peroxynitrous Acid; Phosphoproteins; Phosphorylation; Protein Kinase C; Protein Processing, Post-Translational; Protein Transport; Receptors, Immunologic; Receptors, Thromboxane A2, Prostaglandin H2; RNA Interference; Signal Transduction; Superoxides; Time Factors; Tyrosine

Oxidative stress may increase production of superoxide and nitric oxide, leading to formation of prooxidant peroxynitrite to cause vascular dysfunction. Having found nitrotyrosine residues, a marker of peroxynitrite action, in placental vessels of preeclamptic and diabetic pregnancies, we determined whether vasoreactivity is altered in these placentas and treatment with peroxynitrite produces vascular dysfunction. The responses of diabetic, preeclamptic, and normal placentas to increasing concentrations of the vasoconstrictors U-46619 (10(-9)-10(-7) M) and ANG II (10(-9)-10(-7) M) and the vasodilators glyceryl trinitrate (10(-9)-10(-7) M) and prostacyclin (PGI(2); 10(-8)-10(-6) M) were compared as were responses to these agents in normal placentas before and after treatment with 3.16 x 10(-4) M peroxynitrite for 30 min. Responses to both vasoconstrictors and vasodilators were significantly attenuated in diabetic and preeclamptic placentas compared with controls. Similarly, responses to U-46619, nitroglycerin, and PGI(2), but not ANG II, were significantly attenuated following peroxynitrite treatment. The presence of nitrotyrosine residues confirmed peroxynitrite interaction with placental vessels. Overall, our data suggest that peroxynitrite formation is capable of attenuating vascular responses in the human placenta.

Topics: 15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; Adult; Angiotensin II; Antihypertensive Agents; Diabetes Mellitus, Type 1; Epoprostenol; Female; Fetus; Humans; In Vitro Techniques; Muscle, Smooth, Vascular; Nitrates; Nitric Oxide; Nitroglycerin; Oxidative Stress; Placenta; Pre-Eclampsia; Pregnancy; Reactive Oxygen Species; Tyrosine; Vasoconstriction; Vasoconstrictor Agents; Vasodilator Agents