Diabetic nephropathy is a microvascular complication of diabetes. Its etiology involves metabolic disorder-induced endothelial dysfunction. Endothelium-derived nitric oxide (NO) plays an important role in a number of physiological processes, including glomerular filtration and endothelial protection. NO dysregulation is an important pathogenic basis of diabetic nephropathy. Hyperglycemia and dyslipidemia can lead to oxidative stress, chronic inflammation and insulin resistance, thus affecting NO homeostasis regulated by endothelial nitric oxide synthase (eNOS) and a conglomerate of related proteins and factors. The reaction of NO and superoxide (O₂^.-) to form peroxynitrite (ONOO^-) is the most important pathological NO pathway in diabetic nephropathy. ONOO^- is a hyper-reactive oxidant and nitrating agent in vivo which can cause the uncoupling of eNOS. The uncoupled eNOS does not produce NO but produces superoxide. Thus, eNOS uncoupling is a critical contributor of NO dysregulation. Understanding the regulatory mechanism of NO and the effects of various pathological conditions on it could reveal the pathophysiology of diabetic nephropathy, potential drug targets and mechanisms of action. We believe that increasing the stability and activity of eNOS dimers, promoting NO synthesis and increasing NO/ONOO^- ratio could guide the development of drugs to treat diabetic nephropathy. We will illustrate these actions with some clinically used drugs as examples in the present review.
Diabetes Mellitus ; Diabetic Nephropathies/drug therapy* ; Endothelium, Vascular ; Humans ; Nitric Oxide/metabolism* ; Nitric Oxide Synthase Type III/therapeutic use* ; Oxidative Stress ; Peroxynitrous Acid/therapeutic use*

Peroxynitrite is a highly reactive nitrogen species and a potent inducer of apoptosis and necrosis in somatic cells. Peroxynitrite-induced nitrosative stress has emerged as a major cause of impaired sperm function; however, its ability to trigger cell death has not been described in human spermatozoa. The objective here was to characterize biochemical and morphological features of cell death induced by peroxynitrite-mediated nitrosative stress in human spermatozoa. For this, spermatozoa were incubated with and without (untreated control) 3-morpholinosydnonimine (SIN-1), in order to generate peroxynitrite. Sperm viability, mitochondrial permeability transition (MPT), externalization of phosphatidylserine, DNA oxidation and fragmentation, caspase activation, tyrosine nitration, and sperm ultrastructure were analyzed. The results showed that at 24 h of incubation with SIN-1, the sperm viability was significantly reduced compared to untreated control (P < 0.001). Furthermore, the MPT was induced (P < 0.01) and increment in DNA oxidation (P < 0.01), DNA fragmentation (P < 0.01), tyrosine nitration (P < 0.0001) and ultrastructural damage were observed when compared to untreated control. Caspase activation was not evidenced, and although phosphatidylserine externalization increased compared to untreated control (P < 0.001), this process was observed in <10% of the cells and the gradual loss of viability was not characterized by an important increase in this parameter. In conclusion, peroxynitrite-mediated nitrosative stress induces the regulated variant of cell death known as MPT-driven necrosis in human spermatozoa. This study provides a new insight into the pathophysiology of nitrosative stress in human spermatozoa and opens up a new focus for developing specific therapeutic strategies to better preserve sperm viability or to avoid cell death.
Adult ; Caspases/metabolism* ; Cell Death ; Enzyme Activation ; Humans ; Male ; Mitochondria/pathology* ; Necrosis ; Nitrosative Stress/physiology* ; Permeability ; Peroxynitrous Acid/pharmacology* ; Phosphatidylserines/metabolism* ; Spermatozoa/ultrastructure*

BACKGROUND/OBJECTIVES: Owing to health concerns related to the consumption of traditional snacks high in sugars and fats, much effort has been made to develop functional snacks with low calorie content. In this study, a new recipe for Korean rice cookie, dasik, was developed and its antioxidative, lipid-lowering, and anti-inflammatory effects and related mechanisms were elucidated. The effects were compared with those of traditional rice cake dasik (RCD), the lipid-lowering effect of which is greater than that of traditional western-style cookies. MATERIALS/METHODS: Ginseng-added brown rice dasik (GBRD) was prepared with brown rice flour, fructooligosaccharide, red ginseng extract, and propolis. Mice were grouped (n = 7 per group) into those fed a normal AIN-76 diet, a high-fat diet (HFD), and HFD supplemented with RCD or GBRD. Dasik in the HFD accounted for 7% of the total calories. The lipid, reactive oxygen species, and peroxynitrite levels, and degree of lipid peroxidation in the plasma or liver were determined. The expression levels of proteins involved in lipid metabolism and inflammation, and those of antioxidant enzymes were determined by western blot analysis. RESULTS: The plasma and hepatic total cholesterol concentrations in the GBRD group were significantly decreased via downregulation of sterol regulatory element-binding protein-2 and 3-hydroxy-3-methylglutaryl-CoA reductase (P < 0.05). The hepatic peroxynitrite level was significantly lower, whereas glutathione was higher, in the GBRD group than in the RCD group. Among the antioxidant enzymes, catalase (CAT) and glutathione peroxidase (GPx) were significantly upregulated in the GBRD group (P < 0.05). In addition, nuclear factor-kappaB (NF-κB) expression in the GBRD group was significantly lower than that in the RCD group. CONCLUSIONS: GBRD decreases the plasma and hepatic cholesterol levels by downregulating cholesterol synthesis. This new dasik recipe also improves the antioxidative and anti-inflammatory status in HFD-fed mice via CAT and GPx upregulation and NF-κB downregulation. These effects were significantly higher than those of RCD.
Animals ; Antioxidants ; Blotting, Western ; Carbohydrates ; Catalase ; Cats ; Cholesterol* ; Diet ; Diet, High-Fat ; Down-Regulation ; Fats ; Flour ; Glutathione ; Glutathione Peroxidase ; Inflammation ; Lipid Metabolism ; Lipid Peroxidation ; Liver ; Mice* ; Oxidative Stress* ; Oxidoreductases ; Panax ; Peroxynitrous Acid ; Plasma ; Propolis ; Reactive Oxygen Species ; Snacks ; Sterol Regulatory Element Binding Protein 2 ; Up-Regulation

The aim of this study was to compare serum nitrotyrosine concentrations in healthy dogs with those in dogs with myxomatous mitral valve disease (MMVD). Fifty client-owned dogs were included in this study. Based on echocardiographic results, dogs were categorized into healthy (control), mild-, moderate-, and severe-MMVD groups. Serum nitrotyrosine concentrations were determined from enzyme-linked immunosorbent assays. No significant difference between control dogs and dogs with mild MMVD was detected (p = 0.31). However, dogs with moderate MMVD had significantly higher serum concentrations of nitrotyrosine (p = 0.04) than that in controls, and dogs with severe MMVD had significantly lower serum concentrations of nitrotyrosine (p = 0.03) than that in moderate MMVD dogs. There were negative correlations in the association of serum nitrotyrosine with age (n = 30, R²= 0.067, p = 0.27), left atrial-to-aortic root diameter ratio (n = 30, R²= 0.02, p = 0.57), and platelet count (n = 30, R²= 0.39, p = 0.003); however, only the platelet correlation was significant. Among dogs with MMVD, there was no significant difference in serum nitrotyrosine concentration between males and females. The results of this study suggest that tyrosine nitration end-products might be potential biomarkers for the detection of MMVD in dogs.
Animals ; Biomarkers ; Blood Platelets ; Dog Diseases ; Dogs* ; Echocardiography ; Enzyme-Linked Immunosorbent Assay ; Female ; Humans ; Male ; Mitral Valve* ; Peroxynitrous Acid ; Platelet Count ; Tyrosine

PURPOSE: Peroxynitrite plays a critical role in vascular pathophysiology by increasing arginase activity and decreasing endothelial nitric oxide synthase (eNOS) activity. Therefore, the aims of this study were to investigate whether arginase inhibition and L-arginine supplement could restore peroxynitrite-induced endothelial dysfunction and determine the involved mechanism. MATERIALS AND METHODS: Human umbilical vein endothelial cells (HUVECs) were treated with SIN-1, a peroxynitrite generator, and arginase activity, nitrite/nitrate production, and expression levels of proteins were measured. eNOS activation was evaluated via Western blot and dimer blot analysis. We also tested nitric oxide (NO) and reactive oxygen species (ROS) production and performed a vascular tension assay. RESULTS: SIN-1 treatment increased arginase activity in a time- and dose-dependent manner and reciprocally decreased nitrite/nitrate production that was prevented by peroxynitrite scavenger in HUVECs. Furthermore, SIN-1 induced an increase in the expression level of arginase I and II, though not in eNOS protein. The decreased eNOS phosphorylation at Ser1177 and the increased at Thr495 by SIN-1 were restored with arginase inhibitor and L-arginine. The changed eNOS phosphorylation was consistent in the stability of eNOS dimers. SIN-1 decreased NO production and increased ROS generation in the aortic endothelium, all of which was reversed by arginase inhibitor or L-arginine. N(G)-Nitro-L-arginine methyl ester (L-NAME) prevented SIN-1-induced ROS generation. In the vascular tension assay, SIN-1 enhanced vasoconstrictor responses to U46619 and attenuated vasorelaxant responses to acetylcholine that were reversed by arginase inhibition. CONCLUSION: These findings may explain the beneficial effect of arginase inhibition and L-arginine supplement on endothelial dysfunction under redox imbalance-dependent pathophysiological conditions.
15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid ; Acetylcholine ; Arginase* ; Arginine ; Blotting, Western ; Endothelium ; Human Umbilical Vein Endothelial Cells ; NG-Nitroarginine Methyl Ester ; Nitric Oxide ; Nitric Oxide Synthase Type III* ; Oxidation-Reduction ; Peroxynitrous Acid ; Phosphorylation* ; Reactive Oxygen Species

Reactive oxygen species (ROS) and nitrogen species (RNS) are both important signaling molecules involved in pain transmission in the dorsal horn of the spinal cord. Xanthine oxidase (XO) is a well-known enzyme for the generation of superoxide anions (O₂˙⁻), while S-nitroso-N-acetyl-DL-penicillamine (SNAP) is a representative nitric oxide (NO) donor. In this study, we used patch clamp recording in spinal slices of rats to investigate the effects of O₂˙⁻ and NO on the excitability of substantia gelatinosa (SG) neurons. We also used confocal scanning laser microscopy to measure XO- and SNAP-induced ROS and RNS production in live slices. We observed that the ROS level increased during the perfusion of xanthine and xanthine oxidase (X/XO) compound and SNAP after the loading of 2',7'-dichlorofluorescin diacetate (H₂DCF-DA), which is an indicator of intracellular ROS and RNS. Application of ROS donors such as X/XO, β-nicotinamide adenine dinucleotide phosphate (NADPH), and 3-morpholinosydnomimine (SIN-1) induced a membrane depolarization and inward currents. SNAP, an RNS donor, also induced membrane depolarization and inward currents. X/XO-induced inward currents were significantly decreased by pretreatment with phenyl N-tert-butylnitrone (PBN; nonspecific ROS and RNS scavenger) and manganese(III) tetrakis(4-benzoic acid) porphyrin (MnTBAP; superoxide dismutase mimetics). Nitro-L-arginine methyl ester (NAME; NO scavenger) also slightly decreased X/XO-induced inward currents, suggesting that X/XO-induced responses can be involved in the generation of peroxynitrite (ONOO⁻). Our data suggest that elevated ROS, especially O₂˙⁻, NO and ONOO⁻, in the spinal cord can increase the excitability of the SG neurons related to pain transmission.
Adenine ; Animals ; Humans ; Membranes ; Microscopy, Confocal ; Neurons* ; Nitric Oxide ; Nitrogen* ; Perfusion ; Peroxynitrous Acid ; Rats ; Reactive Oxygen Species* ; Spinal Cord ; Spinal Cord Dorsal Horn ; Substantia Gelatinosa* ; Superoxide Dismutase ; Superoxides ; Tissue Donors ; Xanthine ; Xanthine Oxidase

Compositional differences in flavonoids are varied in the big family of Compositae. By summarizing our previous analytical studies and other scientific evidences, new strategy will be possible to further analyze flavonoids and utilize them for human health. The HPLC analytical method has been established in terms of linearity, sensitivity, accuracy, and precision. Herbs of the family of Compositae have considerable amounts of peroxynitrite (ONOO-)-scavenging effects and their phenolic substances. These effects may contribute to the prevention of disease associated with excess production of ONOO-, depending on the high content of flavonoid substances.
Asteraceae* ; Chromatography, High Pressure Liquid ; Flavonoids ; Humans ; Peroxynitrous Acid ; Phenol

Lactuca raddeana (Compositae) is used to treat obesity and complications due to diabetes. The five phenolic compounds including chlorogenic acid, chicoric acid, luteolin 7-O-glucoside, luteolin 7-O-glucuronide, luteolin were qualitatively identified by LC-ESI-MS analysis. The contents were quantitatively determined by HPLC, under the condition of a Capcell Pak C18 column (5 microm, 250 mm x 4.6 mm i.d.) and a gradient elution of 0.05% trifluoroacetic acid (TFA) and 0.05% TFA in MeOH-H2O (60 : 40). The contents of chicoric acid (100.99 mg/g extract) and luteolin 7-O-glucoside (101. 69 mg/g extract) were high, while those of other three phenolic substances were very low. The 3T3-L1 adipocyte cells treated with chicoric acid and luteolin 7-O-glucuronide significantly suppressed the accumulation of fat, suggesting they are effective against obesity. Since high level of peroxynitrite (ONOO) causes cardiovascular disease in obese patients, its scavenging activity was also studied.
Adipocytes* ; Asteraceae ; Cardiovascular Diseases ; Chlorogenic Acid ; Chromatography, High Pressure Liquid ; Humans ; Luteolin ; Obesity ; Peroxynitrous Acid ; Phenol* ; Trifluoroacetic Acid

Peroxynitrite (ONOO-)-scavenging activities of nine Compositae herbs consisting of three Ixeris, two Youngia, two Cirsium and one of each Lactuca and Taraxacum species were evaluated. The contents of their ONOO- scavengers in the extracts were also determined on a HPLC using seven standard compounds, chlorogenic acid (CGA), chicoric acid (CA), luteolin 7-glucoside (luteolin-7-glc), luteolin 7-glucuronide (luteolin-7-glcU), luteolin, linarin and pectolinarin. Five of those compounds exhibited potent ONOO--scavenging activities: IC50, CA (0.76 microM), CGA (1.34 microM), luteolin (0.81 microM), luteolin-7-glc (0.86 microM) and luteolin-7-glcU (3.13 microM). Both CA and luteolin-7-glc were highly contained in I. dentata (19.71 mg/g and 13.58 mg/g, respectively), I. dentata var. albiflora (17.58 mg/g and 23.83 mg/g, respectively) and I. sonchifolia (65.71 mg/g and 6.99 mg/g, respectively). Among the nine herbs, those three Ixeris species had very low IC50 values over the range of 0.48 - 1.74 microg/mL, suggesting that they could be potential therapeutic vegetables, particularly for preventing diabetic complications or obesity, which can be caused by an excess production of ONOO-.
Asteraceae* ; Chlorogenic Acid ; Chromatography, High Pressure Liquid ; Cirsium ; Diabetes Complications ; Inhibitory Concentration 50 ; Luteolin ; Obesity ; Peroxynitrous Acid ; Phenol* ; Taraxacum ; Vegetables

Cardiovascular disease is the prime cause of morbidity and mortality and the population ages that may contribute to increase in the occurrence of cardiovascular disease. Arginase upregulation is associated with impaired endothelial function in aged vascular system and thus may contribute to cardiovascular disease. According to recent research, Korean Red Ginseng water extract (KRGE) may reduce cardiovascular disease risk by improving vascular system health. The purpose of this study was to examine mechanisms contributing to age-related vascular endothelial dysfunction and to determine whether KRGE improves these functions in aged mice. Young (10+/-3 weeks) and aged (55+/-5 weeks) male mice (C57BL/6J) were orally administered 0, 10, or 20 mg/mouse/day of KRGE for 4 weeks. Animals were sacrificed and the aortas were removed. Endothelial arginase activity, nitric oxide (NO) generation and reactive oxygen species (ROS) production, endothelial nitric oxide synthase (eNOS) coupling, vascular tension, and plasma peroxynitrite production were measured. KRGE attenuated arginase activity, restored nitric oxide (NO) generation, reduced ROS production, and enhanced eNOS coupling in aged mice. KRGE also improved vascular tension in aged vessels, as indicated by increased acetylcholine-induced vasorelaxation and improved phenylephrine-stimulated vasoconstriction. Furthermore, KRGE prevented plasma peroxynitrite formation in aged mice, indicating reduced lipid peroxidation. These results suggest KRGE exerts vasoprotective effects by inhibiting arginase activity and augmenting NO signaling and may be a useful treatment for age-dependent vascular diseases.
Aging ; Animals ; Aorta ; Arginase* ; Cardiovascular Diseases ; Humans ; Lipid Peroxidation ; Male ; Mice* ; Mortality ; Nitric Oxide ; Nitric Oxide Synthase Type III ; Panax* ; Peroxynitrous Acid ; Plasma ; Reactive Oxygen Species ; Up-Regulation ; Vascular Diseases ; Vasoconstriction ; Vasodilation ; Water*