calcimycin and 4-hydroxy-2-nonenal

Altered nitric oxide (NO) biosynthesis is thought to play a role in the initiation and progression of atherosclerosis and may contribute to increased risk seen in other cardiovascular diseases. It is hypothesized that altered NO bioavailability may result from an increase in endogenous NO synthase (NOS) inhibitors, asymmetric dimethly araginine (ADMA), and N(G)-monomethyl arginine, which are normally metabolized by dimethyarginine dimethylamine hydrolase (DDAH). Lipid hydroperoxides and their degradation products are generated during inflammation and oxidative stress and have been implicated in the pathogenesis of cardiovascular disorders. Here, we show that the lipid hydroperoxide degradation product 4-hydroxy-2-nonenal (4-HNE) causes a dose-dependent decrease in NO generation from bovine aortic endothelial cells, accompanied by a decrease in DDAH enzyme activity. The inhibitory effects of 4-HNE (50 microM) on endothelial NO production were partially reversed with L-Arg supplementation (1 mM). Overexpression of human DDAH-1 along with antioxidant supplementation completely restored endothelial NO production following exposure to 4-HNE (50 microM). These results demonstrate a critical role for the endogenous methylarginines in the pathogenesis of endothelial dysfunction. Because lipid hydroperoxides and their degradation products are known to be involved in atherosclerosis, modulation of DDAH and methylarginines may serve as a novel therapeutic target in the treatment of cardiovascular disorders associated with oxidative stress.

Topics: Aldehydes; Amidohydrolases; Animals; Antioxidants; Arginine; Calcimycin; Calcium; Cattle; Cells, Cultured; Dose-Response Relationship, Drug; Endothelial Cells; Enzyme Inhibitors; Glutathione; Humans; Ionophores; Lipid Peroxidation; Nitric Oxide; Nitric Oxide Synthase Type III; Phosphorylation; Recombinant Proteins

To investigate the role of oxidative functions in human osteoarthritic (OA) chondrocytes and to investigate the presence of in vivo molecular markers of lipoxidation in OA cartilage.. An in vitro model of cartilage collagen degradation was used. Lipid peroxidation activity and overall oxidative function in OA chondrocytes were monitored by cis-parinaric acid and dichlorofluorescein assays, respectively. In vivo molecular markers of lipoxidation in normal and OA cartilage were studied using immunohistochemistry to detect the presence of malondialdehyde and hydroxynonenal adducts.. Human OA chondrocytes showed a robust amount of 3H-proline-labeled collagen degradation upon stimulation with lipopolysaccharide and calcium ionophore A21387, as compared with that in untreated OA chondrocytes. Primary OA chondrocytes showed both spontaneous and inducible levels of lipid peroxidation activity. However, lipid peroxidation activity was already maximally elevated in more than 50% of the OA chondrocyte samples. Overall, spontaneous and inducible oxidative activities were observed in all OA samples. Immunohistochemical analysis of control OA tissue sections that were not treated with monoclonal antibody showed little immunoreactivity. OA cartilage sections treated with monoclonal antibodies showed specific immunoreactivity on the cartilage surface, at sites of OA lesions, at the pericellular matrix, and at intra- and intercellular matrices. Normal cartilage sections showed faint surface reactivity.. Our observations suggest that human OA chondrocytes demonstrate spontaneous and inducible cell-associated lipoxidative and nonlipoxidative activity. Lipoxidative activity appears to be enhanced in OA chondrocytes. The presence of molecular markers of in vivo lipid peroxidation was demonstrated in OA cartilage, suggesting its role in the pathogenesis of the disease.

Topics: Adult; Aged; Aldehydes; Antibodies, Monoclonal; Biomarkers; Calcimycin; Cartilage, Articular; Cells, Cultured; Chondrocytes; Collagen; Dose-Response Relationship, Drug; Fatty Acids, Unsaturated; Fluoresceins; Humans; Hydrogen Peroxide; Immunohistochemistry; Ionophores; Joints; Lipid Peroxidation; Lipopolysaccharides; Malondialdehyde; Middle Aged; Osteoarthritis

(E)-4-Hydroxy-2-nonenal (HNE) is a highly reactive product of the oxidation of low density lipoprotein (LDL) which increases the platelet aggregation response to various agonists. HNE formation was increased during the enhanced platelet aggregation to thrombin, ADP. A23187 and epinephrine in the presence of LDL. The increase in platelet aggregation and HNE formation by LDL was inhibited by superoxide dismutase and catalase, suggesting superoxide and hydrogen peroxide produced by platelets during aggregation may be at least partly responsible. The responsiveness of platelets to LDL and the accompanying HNE formation was increased further in the presence of ferrous ion. The effect of ferrous ion on both platelet responses and HNE formation was decreased by superoxide dismutase, catalase and the antioxidants dipyridamole and probucol implicating platelet-derived free radicals. Ferrous ion caused an increase in the release of arachidonic acid from platelet membrane phospholipids in the presence of LDL which was probably caused by increased HNE production. The results suggest iron could increase platelet reactivity at sites of vascular injury by increasing HNE formation and promote the development of atherosclerotic lesions.

Topics: Adenosine Diphosphate; Aldehydes; Antioxidants; Blood Platelets; Calcimycin; Drug Synergism; Epinephrine; Ferrous Compounds; Humans; Iron; Lipoproteins, LDL; Platelet Activation; Platelet Aggregation; Thrombin

Topics: Aldehydes; Animals; Calcimycin; Cell Line, Transformed; Dogs; Herpesvirus 4, Human; Humans; Lymphocytes; Neuronal Ceroid-Lipofuscinoses; Neutrophils; Tetradecanoylphorbol Acetate

(E)-4-Hydroxy-2-nonenal (HNE), a cytotoxic end-product of lipid peroxidation, is present in significant amounts in human semen (0.902 +/- 0.190 microM; mean +/- s.e.; n = 18). The addition of the divalent cation ionophore A23187 to suspensions of human spermatozoa resulted in increased production of HNE. Exogenous HNE was powerfully spermicidal and as little as 50 microM caused an irreversible loss of motility of human spermatozoa within minutes. The addition of human seminal plasma protected spermatozoa from the toxic effects of HNE.

Topics: Aldehydes; Calcimycin; Humans; Lipid Peroxidation; Male; Mass Spectrometry; Semen; Sperm Motility; Spermatozoa

The stimulation by ADP or arachidonic acid of the aggregation of human platelets in plasma was inhibited by 4-hydroxynonenal (HNE). This reduction of aggregation was time related, and was increased by prolonged preincubation of the platelets with the aldehyde. HNE was more potent than its homologue 4-hydroxypentenal (HPE). HNE was less active in decreasing the aggregation induced by calcium ionophore A23187 or collagen in comparison with ADP. HNE was inactive against aggregation of platelet-rich plasma (PRP) stimulated by thrombin whereas it potently inhibited the aggregation of washed platelets in response to both thrombin and collagen. Platelets were found to degrade HNE, and mechanisms additional to covalent binding to glutathione are indicated by the results obtained. The aldehydes, including HNE, generated by platelets originated principally from arachidonic acid metabolism.

Topics: Adenosine Diphosphate; Aldehydes; Arachidonic Acid; Arachidonic Acids; Blood Platelets; Calcimycin; Drug Antagonism; Fatty Acids; Glutathione; Humans; In Vitro Techniques; Malondialdehyde; Platelet Activating Factor; Platelet Aggregation; Thrombin