Plasma NOx Levels Research Articles

Endothelial Dysfunction, Macrophage Infiltration and NADPH Oxidase-Dependent Superoxide Production Were Attenuated by Erythropoietin in Streptozotocin-Induced Diabetic Rat Aorta

Erythropoietin (EPO) has been used for the management of renal anemia. Recent studies suggest the pleiotropic properties of EPO in various tissues such as brain, kidney and vasculature. Diabetes mellitus is a major risk for development of vascular impairment. The aim of the present study was to investigate the hypothesis that EPO would be beneficial in inhibiting diabetic macroangiopathy. Recombinant human EPO (rHuEPO; 150 U/kg, 3 times/week, s.c.) was administered to streptozotocin-induced diabetic rats for 4 weeks. Streptozotocin (65 mg/kg, i.v.) significantly increased macrophage infiltration and adhesion molecules, monocyte chemoattractant protein-1 and osteopontin mRNA levels in the aorta. These inflammatory changes were suppressed by rHuEPO. Vasodilation in response to acetylcholine in the aortic ring was impaired in the diabetic rats, and improved by rHuEPO. rHuEPO inhibited the aortic expression of mRNA for nicotinamide adenine dinucleotide phosphate (NADPH) oxidase and the NADPH oxidase-dependent superoxide production and the increase in plasma malondialdehyde concentration in diabetic rats. rHuEPO also decreased the level of the receptor for advanced glycation end products in the aorta. We also found an increased expression of phospho-Akt and endothelial nitric oxide synthase and plasma NOx level in the rHuEPO-treated group. On the other hand, rHuEPO did not affect blood glucose levels, hemoglobin A_1c, blood pressure or hematocrit in diabetic rats. These results indicate that rHuEPO exerts pleiotropic antioxidant and anti-inflammatory properties in diabetic rat aorta.

Influence of nitrate supplementation on VO2 kinetics and endurance of elite cyclists

The present study examined if an elevated nitrate intake would improve VO(2) kinetics, endurance, and repeated sprint capacity in elite endurance athletes. Ten highly trained cyclists (72 ± 4 mL O(2) /kg/min, mean ± standard deviation) underwent testing for VO(2) kinetics (3 × 6 min at 298 ± 28 W), endurance (120 min preload followed by a 400-kcal time trial), and repeated sprint capacity (6 × 20 s sprints, recovery 100 s) during two 6-day periods in randomized order with a daily ingestion of either 0.5 L beetroot (BR) juice to increase nitrate levels or a 0.5 L placebo (PLA) drink with blackcurrant juice. Plasma NOx (nitrate + nitrite) levels were higher (P < 0.01) in BR (147 ± 102 and 159 ± 103 μM after 4 and 6 days of beverage intake, respectively) compared with PLA (41 ± 10 and 40 ± 7 μM). VO(2) kinetics and exercise economy were the same in BR and PLA. Time-trial performance was similar with an average completion time of 18:20 and 18:37 min:s in BR and PLA, respectively, with average power outputs of 290 ± 43 W in BR and 285 ± 44 W in PLA. Peak and mean power during repeated sprinting were similar in BR and PLA. In contrast to observations in moderately trained subjects intake of BR juice had no effect on VO(2) kinetics and performance in elite cyclists.

Serum nitric oxide metabolites and high sensitivity C-reactive protein are important biomarkers in non obese, Indian type 2 diabetic males

Inflammation, endothelial dysfunction, and oxidative stress are postulated to be the principal events in the pathogenesis of type 2 diabetes mellitus and its vascular complications. Serum Nitric Oxide metabolites (NOX) and high sensitivity C-reactive protein (hs-CRP) were measured in eighty non-obese, type 2 diabetic males (40 to 65 years) without (group B, N = 40) and with vascular disease [16 retinopathy (group C), 24 hypertension (group D)]; and compared with forty healthy, age and sex matched control subjects (group A). The mean age of diabetic patients and healthy controls was 49.5 ± 5.80 vs. 51.0 ± 7.15 years, respectively (P = 0.212). Diabetic group had higher Fasting Plasma Glucose (FPG), hs-CRP, and NOX levels than control group (135.3 ± 28.69 vs. 96.7 ± 10.46; 5.1 ± 2.59 vs. 1.7 ± 0.54; 61.1 ± 15.67 vs. 37.1 ± 3.69, respectively, P = 0.001). When compared with diabetics without complication (53.7 ± 10.37), levels of NOX were significantly higher (P = 0.001) both in retinopathy (74.5 ± 19.39) and hypertension (64.4 ± 13.60) group, whereas that of hs-CRP (4.4 ± 2.85 vs.6.5 ± 2.93, P = 0.015) differed only in retinopathy group. There was no difference between retinopathy and hypertension group. There was significant (P < 0.05) positive correlation between age, duration of diabetes, hs-CRP, and NOX; hs-CRP and NOX among group B and C. A negative correlation was noted between hs-CRP and NOX (r = −0.068, P = 0.752) among hypertensives. By multivariate regression analysis, FPG, hs-CRP and NOX were found to be independent indicators of complications after adjustment for age and duration of diabetes. This study reveals that NOX and hs-CRP are important biomarkers in type 2 diabetes mellitus and its associated vascular complications.

Oxidative stress in multiple sclerosis patients in clinical remission: Association with the expanded disability status scale

Increased levels of oxidative stress markers and/or decreased levels of antioxidant molecules have been described in patients with multiple sclerosis (MS). This imbalance has been implicated in demyelination and axonal damage. The aims of this study were to evaluate oxidative stress in MS patients and to verify its correlation with disability as assessed by the expanded disability status scale (EDSS). This case-controlled study included 91 patients with relapsing–remitting multiple sclerosis (RR-MS) and 196 healthy individuals matched by age, gender, ethnicity, smoking status, and body mass index. Oxidative stress was evaluated by tert-butyl hydroperoxide-initiated chemiluminescence (CL-LOOH), carbonyl protein, nitric oxide metabolites (NOx), total radical-trapping antioxidant parameter (TRAP), sulfhydryl groups of proteins and serum uric acid levels. MS patients exhibited higher plasma levels of CL-LOOH (p<0.0001) and carbonyl protein (p=0.0081), and lower plasma levels of NOx (p<0.0001), TRAP (p=0.0088), and sulfhydryl groups (p=0.0003) compared to the control subjects. A multivariate analysis showed an association between oxidative markers and the presence of MS. Patients with an EDSS >3.5 showed higher CL-LOOH than control subjects (p=0.0093). A positive correlation was observed between CL-LOOH and EDSS (r=0.3244, p=0.0026) and between carbonyl protein and EDSS (r=0.3012, p=0.0041). These results demonstrate that oxidative stress plays an important role in the physiopathology of MS progression.

The dose-dependent immunoregulatory effects of the nitric oxide synthase inhibitor N(G)-nitro-L-arginine methyl ester in rats with sub-acute peritonitis.

BackgroundChronic inflammation accompanied by arginine deficiency, immune dysfunction, and excess nitric oxide (NO) production is a clinical condition found in patients with peritonitis. A previous study showed that the nonselective NOS inhibitor NG-nitro-L-arginine methyl ester (L-NAME) may facilitate the metabolism of the immune nutrient arginine without altering NO homeostasis in rats with sub-acute peritonitis. Here, we investigated the effects of L-NAME on the immunocytic subpopulation distribution and response.Materials and MethodsMale Wistar rats with cecal puncture-induced peritonitis were administered parenteral nutrition solutions supplemented with 0 (CPP group), 5 (LNA group), 25 (MNA group) or 50 (HNA group) mg·kg−1·day−1 of L-NAME for 7 days. Parenteral-fed sham-operated rats (TPN group) and orally-fed healthy rats (R group) were included as controls.ResultsThe TPN group had significantly increased spleen weights and levels of plasma nitrite/nitrate (NOx), circulating white blood cells (WBC), and splenocytic T cells, as well as significantly decreased levels of cytotoxic T- and B-leukocytes and B-splenocytes compared to the R group. The CPP group had significantly decreased levels of plasma NOx and concanavalin (Con) A-stimulated interferon (IFN)-γ and interleukin (IL)-2 production by leukocytes and significantly increased production of Con A-stimulated tumor necrosis factor (TNF)-α and lipopolysaccharide (LPS)-stimulated IFN-γ in the leukocytes. In addition, the LNA and MNA groups had significantly decreased spontaneous IL-6 and Con A-stimulated TNF-α and IFN-γ production by the leukocytes while the HNA group had significantly increased LPS-stimulated TNF-α and Con A-stimulated IFN-γ and IL-2 production by the splenocytes compared to the CPP group.ConclusionsLow-dose L-NAME infusion may suppress proinflammatory and T-helper-1 (Th1) response in leukocytes, and high-dose infusion may activate the proinflammatory response in splenic macrophages and Th1 response in T-splenocytes in rats with sub-acute peritonitis.

Inhaled Hydrogen Sulfide Prevents Endotoxin-Induced Systemic Inflammation and Improves Survival by Altering Sulfide Metabolism in Mice

The role of hydrogen sulfide (H(2)S) in endotoxin (lipopolysaccharide [LPS])-induced inflammation is incompletely understood. We examined the impact of H(2)S breathing on LPS-induced changes in sulfide metabolism, systemic inflammation, and survival in mice. Mice that breathed air alone exhibited decreased plasma sulfide levels and poor survival rate at 72 h after LPS challenge. Endotoxemia markedly increased alanine aminotransferase (ALT) activity and nitrite/nitrate (NOx) levels in plasma and lung myeloperoxidase (MPO) activity in mice that breathed air. In contrast, breathing air supplemented with 80 ppm of H(2)S for 6 h after LPS challenge markedly improved survival rate compared to mice that breathed air alone (p<0.05). H(2)S breathing attenuated LPS-induced increase of plasma ALT activity and NOx levels and lung MPO activity. Inhaled H(2)S suppressed LPS-induced upregulation of inflammatory cytokines, while it markedly induced anti-inflammatory interleukin (IL)-10 in the liver. Beneficial effects of H(2)S inhalation after LPS challenge were associated with restored sulfide levels and markedly increased thiosulfate levels in plasma. Increased thiosulfate levels after LPS challenge were associated with upregulation of rhodanese, but not cystathionine-γ-lyase (CSE), in the liver. Administration of sodium thiosulfate dose-dependently improved survival after LPS challenge in mice. By measuring changes in plasma levels of sulfide and sulfide metabolites using an advanced analytical method, this study revealed a critical role of thiosulfate in the protective effects of H(2)S breathing during endotoxemia. These observations suggest that H(2)S breathing prevents inflammation and improves survival after LPS challenge by altering sulfide metabolism in mice.

Increase in gastric pH reduces hypotensive effect of oral sodium nitrite in rats

The new pathway nitrate–nitrite–nitric oxide (NO) has emerged as a physiological alternative to the classical enzymatic pathway for NO formation from l-arginine. Nitrate is converted to nitrite by commensal bacteria in the oral cavity and the nitrite formed is then swallowed and reduced to NO under the acidic conditions of the stomach. In this study, we tested the hypothesis that increases in gastric pH caused by omeprazole could decrease the hypotensive effect of oral sodium nitrite. We assessed the effects of omeprazole treatment on the acute hypotensive effects produced by sodium nitrite in normotensive and L-NAME-hypertensive free-moving rats. In addition, we assessed the changes in gastric pH and plasma levels of nitrite, NOx (nitrate+nitrite), and S-nitrosothiols caused by treatments. We found that the increases in gastric pH induced by omeprazole significantly reduced the hypotensive effects of sodium nitrite in both normotensive and L-NAME-hypertensive rats. This effect of omeprazole was associated with no significant differences in plasma nitrite, NOx, or S-nitrosothiol levels. Our results suggest that part of the hypotensive effects of oral sodium nitrite may be due to its conversion to NO in the acidified environment of the stomach. The increase in gastric pH induced by treatment with omeprazole blunts part of the beneficial cardiovascular effects of dietary nitrate and nitrite.

Nitric oxide metabolites and arginase I levels in β-thalassemic patients: an Egyptian study

Stored red blood cells become deficient in nitric oxide that limits their ability to transfer oxygen to tissues that need it. The aims of this study are to assess the endogenous nitric oxide metabolites (NOx) and arginase I levels in transfusion-dependent β-thalassemic patients; to compare these levels in patients transfused with fresh RBCs with patients transfused with old RBCs, β-thalassemic minor patients, and normal control; and to correlate these levels with some clinical variables. Group I was composed of 23 patients with homozygous β-thalassemia on hypertransfusion regimen. They were adequately transfused with fresh RBC. Group II was composed of 17 patients with homozygous β-thalassemia on hypertransfusion regimen. They were adequately transfused with old RBCs. Group III was composed of 30 patients with homozygous β-thalassemia. They were adequately transfused with fresh RBCs. Group IV was composed of 18 patients with homozygous β-thalassemia. They were adequately transfused with old RBCs. Both group III and group IV were supposed to be on hypertransfusion regimen, but they did not follow the regimen. Group V was composed of 21 patients of β-thalassemia minor. Nineteen apparently healthy individuals (HbAA) served as a control group (group VI). In addition to routine laboratory investigations, plasma levels of NOx and serum levels of arginase I were assessed in all subjects. The mean values of plasma NOx were significantly decreased in groups III and IV compared to the other groups. Also, the levels of NOx were significantly decreased in patients who received old RBCs compared to the other groups. There were high serum levels of arginase I in groups III and IV compared to the other groups. There were significant negative correlations between plasma NOx and some hemolytic biochemical markers in groups III and IV. There were significant positive correlations between serum arginase I and some hemolytic biochemical markers in groups III and IV. Also, there was a significant negative correlation between plasma NOx and serum arginase I levels in groups III and IV. In non-adequately transfused patients with β-thalassemia major, inactivation of NO correlates with hemolytic rate and is associated with the erythrocyte release of cell-free hemoglobin, which consumes NO directly, and the simultaneous release of the arginine-metabolizing enzyme arginase, which limits bioavailability of the NO synthase substrate, arginine, during the process of hemolysis. New treatments aimed at improving arginine and NO bioavailability through arginase inhibition, suppression of hemolytic rate, oral arginine supplementation, predonation testing, and transfusion of fresh RBCs or use of NO donors represent potential therapeutic strategies for this common hemolytic disorder.

Habitual rowing exercise is associated with high physical fitness without affecting arterial stiffness in older men

The present study elucidated the effects of habitual rowing exercise on arterial stiffness and plasma levels of the vasoconstrictor endothelin-1 and the vasodilator nitric oxide (NO) in older men. Eleven rowers (68.0 ± 1.6 years) and 11 sedentary control older men (64.9 ± 1.1 years) were studied. Peak oxygen uptake (36.0 ± 1.7 vs. 27.7 ±1.9 ml · kg−1 · min−1), leg press power (1346 ± 99 vs. 1077 ± 68 W), and HDL-cholesterol (75 ± 5 vs. 58 ±3 mg · ml−1) were higher and triglyceride (78 ± 9 vs. 120 ± 14 mg · ml−1) was lower in rowers than in control participants (all P < 0.05). Arterial stiffness indices (carotid β-stiffness and cardio-ankle vascular index) and plasma endothelin-1 and NOx (nitrite + nitrate) levels did not differ between the two groups. These results suggest that habitual rowing exercise in older men is associated with high muscle power and aerobic capacity, and favourable blood lipid profile without affecting arterial stiffness or plasma levels of endotheline-1 and NO.

Antihypertensive and antioxidant effects of a single daily dose of sodium nitrite in a model of renovascular hypertension

Dietary nitrite and nitrate have been reported as alternative sources of nitric oxide (NO). In this regard, we reported previously that sodium nitrite added to drinking water was able to exert antihypertensive effects in an experimental model of hypertension in a dose-dependent manner. Taking into consideration that nitrite is continuously converted to nitrate in the bloodstream, here we expanded our previous report and evaluate whether a single daily dose of sodium nitrite could exert antihypertensive effects in 2 kidney-1 clip (2K1C) hypertensive rats. Sham-operated and 2K1C rats were treated with vehicle or sodium nitrite (15mg/kg/day) for 4weeks. We evaluated the effects induced by sodium nitrite treatment on systolic blood pressure (SBP) and NO markers such as plasma nitrite, nitrite + nitrate (NOx), cGMP, and blood levels of nitrosyl-hemoglobin. In addition, we also evaluated effects of nitrite on oxidative stress and antioxidant enzymes. Dihydroethidium (DHE) was used to evaluate aortic reactive oxygen species (ROS) production by fluorescence microscopy, and plasma levels of thiobarbituric acid-reactive species (TBARS) were measured in plasma samples from all experimental groups. Red blood cell superoxide dismutase (SOD) and catalase activity were evaluated with commercial kits. Sodium nitrite treatment reduced SBP in 2K1C rats (P < 0.05). We found lower plasma nitrite and NOx levels in 2K1C rats compared with normotensive controls (both P < 0.05). Nitrite treatment restored the lower levels of nitrite and NOx. While no change was found in the blood levels of nitrosyl-hemoglobin (P > 0.05), nitrite treatment increased the plasma levels of cGMP in 2K1C rats (P < 0.05). Higher plasma TBARS levels and aortic ROS levels were found in hypertensive rats compared with controls (P < 0.05), and nitrite blunted these alterations. Lower SOD and catalase activities were found in 2K1C hypertensive rats compared with controls (both P < 0.05). Nitrite treatment restored SOD activity (P < 0.05), whereas catalase was not affected. These data suggest that even a single daily oral dose of sodium nitrite is able to lower SBP and exert antioxidant effects in renovascular hypertension.

Nitric oxide metabolite levels and assessment of cervical length in the prediction of preterm delivery among women undergoing symptomatic preterm labor

ObjectiveTo evaluate the diagnostic accuracy of measuring cervical length (CL) in combination with cervical and plasma nitric oxide metabolite (NOx) levels to identify women undergoing preterm labor (PTL) who will deliver preterm. MethodsA hospital-based prospective cohort study of 730 women undergoing spontaneous PTL between 24 and 33weeks+6days of pregnancy was conducted. Measurement of cervical and plasma NOx levels and ultrasonographic assessment of CL were performed to find the best model to predict preterm delivery (PTD). Optimal cut-off values were calculated by receiver operating characteristic (ROC) curve analysis. Logistic regression analysis and rank correlation tests were also performed. ResultsCL of 15mm or less, cervical NOx levels greater than 87.6μmol/L, and plasma NOx levels greater than 123μmol/L (P<0.0001) were the only factors significantly associated with PTD within 7days of sampling. This combined model provided high diagnostic accuracy (sensitivity 80.0%; specificity 99.2%). Both cervical and plasma NOx levels were negatively correlated with CL (r=−0.453, P<0.0001 and r=−0.362, P<0.0001, respectively). ConclusionCombined measurement of CL and levels of cervical and plasma NOx could help identify women undergoing symptomatic PTL who are at increased risk of PTD.

The epistasis between vascular homeostasis genes is apparent in essential hypertension

Objective The epistasis influence of vascular homeostasis genes is vital to multigenetic diseases. This study was designed to perceive the possible role of epistasis in the etiology of essential hypertension. Methods We investigated seven polymorphisms of ACE, CYP11B2 and NOS3 epistatically, and SBP, DBP, MAP, ACE activity, plasma aldosterone concentration (PAC) and NOx level in 860 age- and ethnicity-matched unrelated north-Indian subjects. Results The hypertension risk in individuals with interacted-genotypes (IwIw + IwIc) + (4aa), (IcIc) + (4bb + 4ba) and IcIc + 4aa of the CYP11B2 and NOS3 was significantly higher with odds ratio 5.5 (95% CI = 2.9–10.6, P < 0.0001), 2.4 (95% CI = 1.4–4.1, P < 0.0008) and 7.5 (95% CI = 1.6–34.8, P = 0.010), respectively. The odds ratio for hypertension with interacted-haplotypes (−344T/Ic) + (−922A/−786T/4a/894G) and (−344T/Ic) + (−922G/−786C/4a/894G) of CYP11B2 and NOS3 was 5.3 (95% CI = 2.0–14.2, P = 0.005) and 3.9 (95% CI = 1.4–10.4, P = 0.04), respectively; whereas for the protective interacted-haplotypes (−344T/Iw) + (−922A/−786T/4b/894G), the odds ratio was 0.7 (95% CI = 0.5–0.9, P = 0.03). While the interacted-genotypes, IcIc + 4aa correlated with higher SBP and MAP ( P = 0.006; P = 0.04), the interacted-haplotypes, (−344T/Ic) + (−922A/−786T/4a/894G) and (−344T/Ic) + (−922G/−786C/4a/894G) correlated with higher MAP and lower NOx level ( P = 0.02 and P = 0.03, respectively), and the protective interacted-haplotypes (−344T/Iw) + (−922A/−786T/4b/894G) correlated with lower PAC and MAP ( P = 0.024 and P = 0.018, respectively). Conclusions The epistasis between CYP11B2 and NOS3 and its correlation with varied clinical and biochemical parameters signify its possible contribution in the complex etiology of hypertension.

Three polymorphisms of the eNOS gene and plasma levels of metabolites of nitric oxide in depressed Japanese patients: a preliminary report

Depression is a risk factor for coronary heart disease. Nitric oxide (NO) plays an important role in both coronary heart disease and depression. Fifty-one inpatients and outpatients who met the Diagnostic and Statistical Manual of Mental Disorders--Fourth Edition criteria for major depressive disorder (MDD) in the university hospital of the University of Occupational and Environmental Health and 58 age-matched and sex-matched healthy controls enrolled in this study. We investigated the association between the three polymorphisms of the endothelial nitric oxide synthase (eNOS) gene (single-nucleotide polymorphism (SNP); rs2070744, rs1799983, variable number tandem repeat (VNTR) in intron 4) and scores on the Hamilton Rating Scale for Depression, plasma metabolites of NO (NO(x) ) or ankle brachial index in patients with MDD and healthy controls. We did not find significant differences in the genotype distributions between patients with MDD and healthy volunteers. No associations were observed between any of the polymorphisms of the eNOS gene and the Hamilton Rating Scale for Depression or ankle brachial index in patients with MDD. However, plasma NO(x) level was significantly associated with a polymorphism of the eNOS gene (rs207044 and variable number tandem repeat in intron 4). These results suggest that the direct association was not observed between the polymorphisms of the eNOS gene and the pathogenesis of depression.

The short-term consumption of a moderately high-fat diet alters nitric oxide bioavailability in lean female Zucker rats

To determine whether short-term consumption of a moderately high-fat diet (MHFD) affects nitric oxide (NO) production, the concentration of stable NO metabolites (NOx) in urine and plasma of rats fed a MHFD (15.6%g fat) or control diet (4.5%g fat) was measured weekly for 4weeks. Plasma and urine NOx levels were significantly depressed in the MHFD group by week 1 and remained so for the duration of the study. Decreased NO bioavailability may result from a decrease in NO production or the scavenging of NO by reactive oxygen species (ROS). Because endothelial NOS (eNOS) is the major contributor to NO production and circulating levels of NOx, eNOS expression was measured in several tissues. At week 1, there was a MHFD-associated decrease in eNOS expression in the liver. Subsequently, eNOS expression declined in the heart and kidney medulla of MHFD-fed rats at weeks 3 and 4, respectively. The expression of eNOS in the kidney cortex and adipose tissue did not change. These results suggest that a MHFD alters eNOS expression in a time-dependent and tissue-specific manner. In the liver, NOS activity and tissue levels of NOx and nitrotyrosine were measured. Nitrotyrosine levels were used as an indirect measure of the NO scavenged by ROS. There was a decrease in NOS activity, suggesting that the low levels of hepatic NOx were due, in part, to a decrease in NO production. In addition, there was a dramatic increase in nitrotyrosine formation, suggesting that the decline in hepatic NOx was also due to an increased interaction of NO with ROS. Tyrosine nitration commonly has detrimental effects on proteins. The decrease in NO and increase in protein nitration could potentially have adverse effects on tissue function.

Leptin promotes melanoma tumor growth in mice related to increasing circulating endothelial progenitor cells numbers and plasma NO production

BackgroundEpidemiological studies propose that obesity increases the risk of several cancers, including melanoma. Obesity increases the expression of leptin, a multifunctional peptide produced predominantly by adipocytes which may promote tumor growth. Several recently experiments have suggested that the tumors growth is in need of endothelial progenitor cell (EPC) dependent generation of new blood vessels.Our objectives in the present study were to examine the effects of leptin on melanoma growth, circulating EPCs number and plasma levels of nitric oxide metabolites (NOx).Methods2 × 106 B16F10 melanoma cells were injected to thirty two C57BL6 mice subcutaneously. The mice were randomly divided into 4 groups (n = 8) in 8th day. Two groups were received twice daily intraperitoneal(i.p) injections of either PBS or recombinant murine leptin (1 μg/g initial body weight). Two groups were received i.p. injections of either 9F8 an anti leptin receptor antibody or the control mouse IgG at 50 μg/mouse every 3 consecutive days. By the end of the second week the animals were euthanized and blood samples and tumors were analyzed.ResultsThe tumor weight, EPC numbers and NOx level in leptin, PBS, 9F8, and IgG group were (3.2 ± 0.6, 1.7 ± 0.3, 1.61 ± 0.2,1.7 ± 0.3 g), (222.66 ± 36.5, 133.33 ± 171, 23.33 ± 18, 132.66 ± 27.26/ml of blood), and (22.47 ± 5.5, 12.30 ± 1.5, 6.26 ± 0.84, 15.75 ± 6.3 μmol/L) respectively. Tumors weight and size, circulating EPC numbers and plasma levels of NOx were significantly more in the leptin than 9f8 and both control groups (p < 0.05). The plasma concentration of NOx significantly decreased in 9f8 treated mice compare to control group (p < 0.05).ConclusionsIn conclusion, our observations indicate that leptin causes melanoma growth likely through increased NO production and circulating EPC numbers and consequently vasculogenesis.

Recombinant human erythropoietin ameliorated endothelial dysfunction and macrophage infiltration by increasing nitric oxide in hypertensive 5/6 nephrectomized rat aorta

Recombinant human erythropoietin (rHuEPO), used clinically for renal anemia, reportedly exhibits pleiotropic properties in various tissues. To test whether it ameliorates vascular injury, rHuEPO (75U/kg) was administered subcutaneously every 3days for 10days to 5/6 nephrectomized hypertensive rats (5/6Nx) treated with 1% NaCl. rHuEPO had no effect on increased systolic blood pressure or decreased hematocrit values, but normalized levels of proteinuria and creatinine clearance. Vasodilation in response to acetylcholine in the aortic ring was impaired in the 5/6Nx, and improved by treatment with rHuEPO. Immunohistochemical analysis revealed that the infiltration of adventitial areas by macrophages and expression of osteopontin were enhanced in the 5/6Nx aorta and the overexpression was suppressed by rHuEPO. rHuEPO also attenuated medial hyperplasia. Akt signaling was activated by the increased expression of phosphorylated Akt and GSK-3β in aorta from rHuEPO-treated 5/6Nx. rHuEPO restored plasma NOx (NO2−+NO3−) levels and endothelial nitric oxide synthase (eNOS) content in the 5/6Nx aorta. Treatment with an eNOS substrate, l-arginine, which caused a similar increase in plasma NOx levels as the rHuEPO treatment, resulted in a normalization of endothelial dysfunction and vascular inflammation. These results suggest that a low dose of rHuEPO exerted vasoprotective effects in rats with hypertensive renal failure.

Plasma NOx Concentrations in Glucose Intolerance and Type 2 Diabetes

The Vietnamese develop type 2 diabetes (T2D) and metabolic syndrome (MS) at a lower BMI than other ethnicities. Thus, biomarkers that identify subjects at an increased risk of T2D independently of obesity are being sought. Recent studies show that circulating NO metabolites (NOx) are increased in T2D. We investigated whether plasma NOx levels predict insulin resistance and glucose intolerance before the development of T2D, independently of obesity. The current study was derived from a population-based study in HCMC, Vietnam, which was designed to investigate the prevalence of MS and T2D in a population aged 30-69 years. Four hundred and twenty-two subjects were recruited from the study and were stratified into 4 age- and gender-matched groups according to a glucose tolerance test {normal glucose tolerance (NGT), impaired fasting glucose (IFG), impaired glucose tolerance (IGT) and T2D}. Plasma NOx concentrations were significantly increased in T2D but not in IFG or IGT compared with NGT. Multiregression analysis showed that plasma NOx levels were inversely correlated with BMI in T2D whereas no association was found between plasma NOx levels and BMI in non-diabetic subjects. Moreover, there was no correlation between plasma NOx levels and homeostasis model assessment-insulin resistance (HOMA-IR) in both diabetic and non-diabetic subjects. Plasma NOx levels did not predict glucose intolerance or insulin resistance before the development of T2D and the increase in plasma NOx levels in T2D was not caused by adiposity. Thus, plasma NOx is not a useful marker for the prediction of high-risk subjects for T2D among Vietnamese.

Altered Regulation of Renal Nitric Oxide and Atrial Natriuretic Peptide Systems in Lipopolysaccharide-induced Kidney Injury

Nitric oxide (NO) and atrial natriuretic peptide (ANP) may induce vascular relaxation by increasing the production of cyclic guanosine monophosphate (cGMP), an important mediator of vascular tone during sepsis. This study aimed to determine whether regulation of NO and the ANP system is altered in lipopolysaccharide (LPS)-induced kidney injury. LPS (10 mg.kg(-1)) was injected in the tail veins of male Sprague-Dawley rats; 12 hours later, the kidneys were removed. Protein expression of NO synthase (NOS) and neutral endopeptidase (NEP) was determined by semiquantitative immunoblotting. As an index of synthesis of NO, its stable metabolites (nitrite/nitrate, NOx) were measured using colorimetric assays. mRNA expression of the ANP system was determined by real-time polymerase chain reaction. To determine the activity of guanylyl cyclase (GC), the amount of cGMP generated in response to sodium nitroprusside (SNP) and ANP was calculated. Creatinine clearance decreased and fractional excretion of sodium increased in LPS-treated rats compared with the controls. Inducible NOS protein expression increased in LPS-treated rats, while that of endothelial NOS, neuronal NOS, and NEP remained unchanged. Additionally, urinary and plasma NOx levels increased in LPS-treated rats. SNP-stimulated GC activity remained unchanged in the glomerulus and papilla in the LPS-treated rats. mRNA expression of natriuretic peptide receptor (NPR)-C decreased in LPS-treated rats, while that of ANP and NPR-A did not change. ANP-stimulated GC activity reduced in the glomerulus and papilla. In conclusion, enhancement of the NO/cGMP pathway and decrease in ANP clearance were found play a role in the pathogenesis of LPS-induced kidney injury.

Characteristics of plasma NOx levels in severe sepsis: high interindividual variability and correlation with illness severity, but lack of correlation with cortisol levels

Characteristics of plasma NOx levels in severe sepsis: high interindividual variability and correlation with illness severity, but lack of correlation with cortisol levels

Inhibition of the renal renin‐angiotensin system and renoprotection by pitavastatin in type 1 diabetes

1. The aim of the present study was to investigate whether or not pitavastatin ameliorates diabetic nephropathy and if inhibition of the rennin-angiotensin-aldosterone system (RAAS) is associated with any renoprotective effects. Pitavastatin (10mg/ kg/day) and/or spironolactone (100mg/kg/day) were given by gavage for 3weeks to uninephrectomized rats with streptozotocin-induced diabetes. 2. Pitavastatin or spironolactone significantly reduced proteinuria and collagen deposition, and normalized creatinine clearance, serum creatinine levels and blood urea nitrogen concentrations. 3. Reverse transcription polymerase chain reaction analysis showed that the renal expression of collagenI, transforming growth factor-β and monocyte chemoattractant-1 were increased in diabetic rats and reduced by the pitavastatin and/or spironolactone treatment. 4. These agents also decreased angiotensin converting enzyme expression and aldosterone concentrations in the renal homogenate, but had no effect on blood glucose, haemoglobinA(1c) , and plasma total cholesterol, Na(+) , K(+) , aldosterone and NOx levels, or on systolic blood pressure measured by the tail-cuff method. Interestingly, cotreatment with pitavastatin and spironolactone did not result in additional normalization. 5. These results suggest that pitavastatin shows renoprotective effects against diabetic nephropathy mediated in part by inhibition of the renal RAAS, including the suppression of angiotensin-converting enzyme expression and aldosterone production.