Nitric Oxide End Products Research Articles

Effects of ischemic preconditioning protocols on skeletal muscle ischemia–reperfusion injury

BackgroundIschemic preconditioning (IPC) is described as brief ischemia–reperfusion (I/R) cycles to induce tolerance to subsequent in response to longer I/R insults. Various IPC protocols can be performed in four combinations as follows: at early or late phases and on local or distant organs. Although many experimental studies have been performed on IPC, no consensus has been established on which IPC protocol is most effective. The aims of the present study were as follows: (1) to compare the variables of preconditioning in different combinations (in early versus late phases; local versus remote organ implementations) and (2) to determine the most therapeutic IPC protocol(s). Materials and methodsA subtotal hind limb amputation model with clamping an intact femoral pedicle was used for I/R injury. IPC was induced using hind limb tourniquet with 3 × 10 min I/R cycles before longer I/R insult. Forty-nine rats were divided into seven groups (n = 7), sham, IsO (ischemia only), I/R, early ischemic preconditioning (e-IPC), late ischemic preconditioning (l-IPC), early remote ischemic preconditioning (e-RIPC), and l-RIPC (late-remote) groups, respectively. In the sham group, pedicle occlusion was not performed. Six hours ischemia was challenged in the IsO group. Three hours ischemia followed by 3 h reperfusion was performed in the I/R group. The e-IPC group was immediately preconditioned, whereas the l-IPC group was preconditioned 24 h before I/R injury on the same hind limb. In the e-RIPC and l-RIPC groups, the same protocols were performed on the contralateral hind limb. At the end of the experiments, skeletal muscle tissue samples were obtained for biochemical analysis (Malondialdehyde [MDA], catalase, myeloperoxidase [MPO], and nitric oxide end products [NOx]), light microscopy, and caspase-3 immunohistochemistry for determination of apoptosis. ResultsTissue biochemical markers were improved in nearly all the IPC groups compared with IsO and I/R groups (P < 0.05). Similarly, the histologic damage scores were decreased in all the IPC groups (P < 0.05). The lowest damage score was in the e-RIPC group followed by the l-RIPC, e-IPC, and l-IPC groups, respectively. The apoptosis scores were significantly high in the I/R group compared with the e-RIPC and l-RIPC groups (P < 0.05). Although apoptosis scores of the e-IPC and l-IPC groups were lower than the I/R group, this finding was not statistically significant (P > 0.05). ConclusionsAll IPC protocols were effective in reducing I/R injury. Among these protocols, e-RIPC achieved most protection.

Increased NT-proANP predicts risk of congestive heart failure in Cavalier King Charles spaniels with mitral regurgitation caused by myxomatous valve disease

ObjectivesTo evaluate the predictive value of plasma N-terminal pro-atrial natriuretic peptide (NT-proANP) and nitric oxide end-products (NOx) as markers for progression of mitral regurgitation caused by myxomatous mitral valve disease. AnimalsSeventy-eight privately owned Cavalier King Charles spaniels with naturally occurring myxomatous mitral valve disease. MethodsProspective longitudinal study comprising 312 measurements over a 4.5 year period. Clinical values were recorded, NT-proANP concentrations were measured by radioimmunoassay, and NOx were analyzed colorimetrically. To predict congestive heart failure (CHF), Cox proportional hazards models with time-varying covariates were constructed. ResultsThe hazard ratio for NT-proANP (per 1000 pmol/l increase) to predict future CHF was 6.7 (95% confidence interval, 3.6–12.5; p < 0.001). The median time to CHF for dogs with NT-proANP levels >1000 pmol/l was 11 months (95% confidence interval, 5.6–12.6 months), compared to 54 months (46 – infinity) for dogs with concentrations ≤1000 pmol/l (p < 0.001). Due to intra- and inter-individual variability, most corresponding analyses for NOx were insignificant but dogs reaching CHF had a lower mean NOx concentration than dogs not reaching CHF (23 vs. 28 μmol/l, p = 0.016). Risk of CHF increased with increase in heart rate (>130 beats per minute) and grade of murmur (≥3/6). ConclusionsThe risk of CHF due to mitral regurgitation is increased in dogs with blood NT-proANP concentrations above 1000 pmol/l. Measurement of NT-proANP can be a valuable tool to identify dogs that may develop CHF within months.

Asymmetric dimethyl arginine levels in testicular tissue and blood of rats with induced experimental varicocele

IntroductionVaricocele is one of the reasons for testicular dysfunction and is frequently known to accompany infertility. The basic pathology of varicocele is the development of endothelial dysfunction. The most important factors in development of endothelial dysfunction are impaired endothelial-linked vasodilatation, increase in free oxygen radicals, reduced synthesis and release of nitric oxide (NO), abnormal vasoconstriction and increased levels of dimethyl arginine. Our aim was to identify and illustrate the relationship between asymmetric dimethyl arginine (ADMA) and NO levels in testicular tissue and plasma of rats with induced experimental varicocele. Materials and methodsTwenty-one adolescent (average 6 weeks) male rats were included in the study and randomly divided into 3 groups. Group 1 (control, n=6) did not undergo any procedure. Group 2 (sham, n=6) had the left renal vein circled proximally but ligation was not performed. Group 3 (varicocele-induced, n=9) had partial ligation of the proximal left renal vein to induce left varicocele. Superoxide dismutase (SOD) enzyme activity and levels of end-products of NO, nitrite and nitrate salts were investigated in testis tissue. Nitrite/nitrate and ADMA levels were investigated in plasma. Histopathological examination was completed with routine hematoxylin–eosine and TUNEL dyes. ResultsTissue SOD and plasma ADMA values were clearly increased in the varicocele group compared to the other groups; tissue and plasma nitrite/nitrate levels were clearly reduced in the varicocele group and this was observed to be statistically significant between the groups. ConclusionWe believe our study has opened an important window on the relationship between infertility observed in varicocele patients and ADMA. We believe that broad-series prospective studies to support this are required.

In-utero Exposure to Maternal Diabetes Increase the Risk of Vascular Diseases in the F1 Offspring in Rats

Background: Maternal diabetes is one of the fundamental intrauterine disturbances that have direct and long lasting consequences on the health of the offspring. The risk for an individual to develop various vascular diseases throughout life is hypothesized to be related to diabetic gestation. Aim: The present study aimed to evaluate the postnatal levels of different independent risk factors for vascular diseases including homocysteine (Hcy), nitric oxide (NO), lipid profile, glucose homeostasis and insulin resistance in the rat offspring of diabetic mothers. The effect of postnatal feeding with high caloric diet (HCD) was also assessed. Methods: Two groups of female Wistar rats were used (diabetic and control); diabetes was neonatally induced by STZ injection to 5-day old rats. Pregnancy was induced by mating control or diabetic females with normal healthy males overnight and the pregnancies were completed to term. After delivery the offspring were weaned to control diet (CD) or high-caloric diet (HCD) (Table 1) and followed up for 30 weeks. So the offspring groups were as following: F1 offspring of control mothers under control diet (CF1CD), F1 offspring of control mothers under HCD (CF1-HCD), F1 offspring of diabetic mothers under control diet (DF1-CD) and F1 offspring of diabetic mothers under HCD (DF1-HCD). Every 5 weeks 0.5 ml blood samples were obtained from the 20 male and female rats for assessment of fasting blood glucose, insulin, triglycerides, cholesterol (total, HDL-C and LDL-C), homocysteine and nitric oxide end products (NOx). Results: The results indicated that maternal diabetes caused an age-dependent alteration in glucose homeostasis and resulted in insulin resistance especially in male offspring. Also, lipid profile showed

Nitric oxide production by polymorphonuclear leucocytes in infected cystic fibrosis sputum consumes oxygen

Chronic Pseudomonas aeruginosa lung infection in cystic fibrosis (CF) patients is characterized by persisting mucoid biofilms in hypoxic endobronchial mucus. These biofilms are surrounded by numerous polymorphonuclear leucocytes (PMNs), which consume a major part of present molecular oxygen (O(2)) due to production of superoxide (O(2)(-)). In this study, we show that the PMNs also consume O(2) for production of nitric oxide (NO) by the nitric oxide synthases (NOS) in the infected endobronchial mucus. Fresh expectorated sputum samples (n = 28) from chronically infected CF patients (n = 22) were analysed by quantifying and visualizing the NO production. NO production was detected by optode measurements combined with fluorescence microscopy, flow cytometry and spectrophotometry. Inhibition of nitric oxide synthases (NOS) with N(G) -monomethyl-L-arginine (L-NMMA) resulted in reduced O(2) consumption (P < 0·0008, n = 8) and a lower fraction of cells with fluorescence from the NO-indicator 4-amino-5-methylamino-2',7'-difluorofluorescein diacetate (DAF-FM) (P < 0·002, n = 8). PMNs stained with DAF-FM and the superoxide indicator hydroethidine (HE) and host cells with inducible NOS (iNOS) were identified in the sputum. In addition, the production of the stable end-products of NO in CF sputum was correlated with the concentration of PMNs; NO(3)(-) (P < 0·04, r = 0·66, n = 10) and NO(2)(-) (P< 0·006, r = 0·78, n = 11). The present study suggests that besides consumption of O(2) for production of reactive oxygen species, the PMNs in CF sputum also consume O(2) for production of NO.

Oral probiotic VSL#3 attenuates the circulatory disturbances of patients with cirrhosis and ascites

The modulation of gut flora constitutes a therapeutic tool in patients with liver disease, but some of its modalities require further investigation. Here, we evaluated the effects of probiotics on the hepatic and systemic haemodynamic alterations of advanced liver disease. Seventeen patients with cirrhosis and ascites were prospectively included, five of whom abandoned this study prematurely. Hepatic and systemic haemodynamic evaluations were performed at baseline and after 6 weeks of receiving an oral VSL#3 probiotic preparation. Peripheral blood analyses included the evaluation of cytokines (TNF-alpha, IL-1beta, IL-6), bacterial translocation [bacterial DNA and lipopolysaccharide-binding protein (LBP)] and nitric oxide end-products (NOx). In 12 patients completing this study, the oral administration of VSL#3 resulted in reductions of the hepatic venous pressure gradient (HVPG, P < 0.001), cardiac index and heart rate (both P < 0.01) and in increases of the systemic vascular resistance (P < 0.05) and mean arterial pressure (P = 0.06). HVPG decreased at least 10% from baseline in eight patients (67%). Serum sodium increased in most patients (P < 0.01). All these changes were unrelated to the detection of bacterial DNA or to the levels of LBP, pro-inflammatory cytokines or NOx. No significant adverse effects were observed. Administration of the probiotic mixture VSL#3 improved the hepatic and systemic haemodynamics and serum sodium levels in patients with cirrhosis. Our results identify major effects of probiotics in liver disease and provide the rationale for assessing their therapeutic potential against the progression of portal hypertension and its complications in future clinical trials.

A mechanistic study on the cardiotoxicity of 5-fluorouracil in vitro and clinical and occupational perspectives

Fluoropyrimidines are key agents for the treatment of gastrointestinal tract adenocarcinomas. The possible cardiotoxic effects in patients and occupationally exposed workers are multifactorial and remain a puzzle to solve for investigators. In the present study, we study what cell death pathways and what doses can determine direct cardiotoxic effects of 5-fluorouracil (5-FU) and doxorubicin (DOXO) on rat cardiocytes (H9c2) and a human colon adenocarcinoma (HT-29) cell line, already reported to be sensitive to 5-FU. We have found that 5-FU induced 50% growth inhibition (IC:50) at 72h with concentrations of 400μM and 4μM on H9c2 and HT-29, respectively. Moreover, we have found that the addition of Levofolinic Acid (LF) to 5-FU potentiated the growth inhibition induced by 5-FU. The growth inhibition induced by 5-FU alone or in combination with LF in cardiocytes was paralleled by an increase of thiobarbituric acid-reactive species (Tbars) and end products of nitric oxide (NO) suggesting the increase of the oxidative stress status in cardiocytes. Interestingly, these effects were strongly potentiated by the addition of LF, a biochemical modulator of 5-FU activity.Our data suggest that agents such as 5-FU different from anthracyclines, conventionally related to the induction of cardiotoxic effects, can also induce cardiocyte damage paralleled by oxidative stress. The strategies based upon the use of scavengers could be used in order to prevent this effect.

Reactive oxygen species and serum antioxidant defense in juvenile idiopathic arthritis

In autoimmune inflammatory diseases, including juvenile idiopathic arthritis (JIA), which leads to joint destruction, there is an imbalance between production of reactive oxygen species (ROS) and their neutralization which, as a consequence, leads to “oxidative stress.” The aim of the study was to assess the concentration of oxidative stress markers: nitric oxide (NO), a degree of lipid membrane damage, and total antioxidant plasma capacity in children with JIA. Thirty-four children with JIA were included into the study. A degree of lipid membrane damage (lipid peroxidation products) was estimated as thiobarbituric acid-reactive substances (TBARs), NO concentration as NO end-products: nitrite/nitrate (NO2 −/NO3 −) and total antioxidant plasma capacity as ferric reducing ability of plasma (FRAP). NO2 −/NO3 − serum concentration in children with JIA was statistically significantly higher than that in healthy children (p = 0.00069). There was no significant difference in TBAR levels between children with JIA and the control group. FRAP in sera of children with JIA was lower than that in healthy children, but the difference was not statistically significant. A statistically significant positive correlation was observed between NO end products and the 27-joint juvenile arthritis disease activity score (JADAS-27) and ESR, and a negative correlation was observed between FRAP and C-reactive protein (CRP) and white blood cell count (WBC). Our results confirm the increased oxidative stress in children with JIA. Overproduction of NO and decrease in the antioxidant plasma capacity may be involved in JIA pathogenesis.

ANTIATHEROGENIC AND PLEIOTROPIC ACTIVITY OF VARIOUS DOSES OF ATORVASTATIN IN PATIENTS WITH ISCHEMIC STROKE

Aim. To study the effects of various atorvastatin doses on blood lipids, hemostatic parameters, endothelial function, renin-angiotensin￾aldosterone (RAAS) system, and circadian profile of blood pressure (BP) in patients with ischemic stroke (IS). Material and methods. The study included 34 IS patients (mean age 58,0±6,6 years) with serum levels of low-density lipoprotein cholesterol (LDL-CH) &gt;2,5 mmol/l, arterial hypertension (AH), and BP levels &lt;160/100 mm Hg. All participants were randomised into Groups I and II, which received atorvastatin in daily doses of 10 and 40 mg, respectively, for 12 weeks. The atorvastatin effects on lipid profile, hemostatic parameters, nitric oxide (NO) end products, endothelin-1 (ET-1), angiotensin (AT) II, blood serotonin, and BP dynamics were assessed. Results. After 12 weeks, the patients receiving 10 and 40 mg/d of atorvastatin demonstrated a significant reduction in total CH (by 26,6% (p&lt;0,001) and 33% (p&lt;0,001), respectively), LDL-CH (by 32% (p&lt;0,001) and 44% (p&lt;0,001), respectively), and triglycerides (TG) (by 14% (p&lt;0,001) and 24% (p&lt;0,001), respectively). In both groups, there was no marked dynamics in the initially elevated levels of fibrinogen. In Group I, spontaneous platelet aggregation (PA) reduced by 22,6% (p&lt;0,05). Moreover, in Group I, ADP-induced PA decreased by 16,7% (p&lt;0,05) and 67,2% (p&lt;0,01) for 0,5 and 2 μM of ADP, respectively. In Group II, the respective figures were 30,1% (p&lt;0,05) and 31,6% (p&lt;0,01). The concentration of NO end products increased in both Group I (+15% (p&lt;0,05) after 12 weeks) and Group II (+7,7% (p&lt;0,05) after 6 weeks; +15,5% (p&lt;0,01) after 12 weeks). In all participants (Groups I and II; n=34), atorvastatin therapy was associated with a reduction in ET-1 levels by 4,8% (p&lt;0,05). In Group II, there was a significant reduction in the levels of AT II (-7,1%; p&lt;0,05; n=17) and serotonin (-28,6%; p&lt;0,05; n=11). These changes were accompanied by reduced BP variability, time BP index, and area BP index. Conclusion. In IS patients with hyperlipidemia and AH, atorvastatin demonstrated a dose-dependent lipid-lowering effect on LDL-CH and TG, as well as a dose-dependent pleiotropic activity.

Impact of low versus upper range intensity exercise training on endothelial function in patients with heart failure

Purpose: To evaluate the impact of low versus upper range intensity exercise training on endothelial function, through assessment of circulating blood markers of endothelial function: the stable end product of Nitric Oxide (NOx), dimethylarginine (ADMA), symmetric dimethylarginine (SDMA) and xanthine oxidase (XO), in patients (pts) with Heart Failure (HF). Methods: Twenty male pts admitted at residential rehabilitation center (mean age 54.1±11.1 years) with ejection fraction <40%, were studied. Patients were randomized to low intensity exercise (40% heart rate reserve; LI group, n=9) and to upper range intensity exercise (70% heart rate reserve; UI group, n=11). Patients exercised twice a day at residential center over a period of 3 weeks. At baseline and 3 weeks later, in all pts values of NOx, ADMA, SDMA and XO were evaluated and exercise test was performed. Results: After 3 weeks NOx increased significantly in both groups: in LI group (from 33.2±4.1 to 38.8±6.0 μmol/l, P=0.006), and in UI group (from 32.3±6.9 to 52.2±14.5 μmol/l, P<0.0005), however increase in NOx was higher in UI than in LI group (P=0.041). Value of ADMA as well of SDMA decreased significantly in both groups after 3 weeks: in LI (P=0.003 and P=0.004) and in UI group (P=0.001 and P=0.071). At the end of the study value of ADMA was significantly lower in UI than in LI group (P=0.025).Compared to the baseline, value of XO at the end of the study was significantly lower in both groups (P<0.0005 both). After 3 weeks level and duration of test increased in both groups, however level of exercise test was significantly higher only in UI group, compared to baseline exercise test (P=0.005). Conclusion: Residential 3 weeks low, as well as, upper range intensity exercise training induced improvement in endothelial function in patients with HF. More significant increase of NOx, decrease of ADMA and increase of exercise capacity in UI group give an advantage to upper range over low intensity exercise training in patients with HF.

Effects of music therapy on endothelial function in patients with coronary artery disease participating in rehabilitation

Purpose: To evaluate the effects of listening to favorite music on the endothelial function, assess through changes of circulating blood markers of endothelial function: the stable end product of Nitric Oxide (NOx), Dimethylarginine (ADMA), Symmetric Dimethylarginine (SDMA) and Xanthine Oxidase (XO), in patients (pts) with Coronary Artery Disease (CAD). Methods: 74pts with stable CAD were studied. At baseline and 3 weeks later, in all pts values of NOx, ADMA, SDMA and XO were evaluated and exercise test was performed. After the initial study, pts were randomized to trained (T,n=33), music and trained (MT, n=31) and music (M,n=10) group. Patients in T and MT group underwent a supervised 3 weeks aerobic exercise training at residential center. Additional to exercise training, patients in MT group were listening to their favorite music, for half an hour, every day. Patients in M group received usual community care and were listening to their favorite music for half an hour every day. Results: After 3 weeks NOx increased in T group (from 33.0±13.0 to 42.8±11.0 μmol/l, P< 0.005), MT group (from 34.5±7.1 to 49.6±12.6 μmol/l, P<0.0005) and M group (from 32.8±6.5 to 36.5±7.0 μmol/l, ns). However increase in NOx was higher in MT than in T and M group (P=0.0246 and P<0.005), and in T than in M group (P<0.05). Value of ADMA as well of SDMA decreased in all three groups (ns) after 3 weeks, and this reduction was the most pronounced in MT group. Compared to the baseline, value of XO at the end of the study was significantly lower in T, MT and M group (P<0.0005 for all of them). However at the end of the study value of XO was significantly lower in MT than in T and M group (P<0.005 and P<0.0005) and in T than in M group (P<0.001). After 3 weeks exercise capacity significantly increased in T, MT and M group (P<0.001, P<0.001 and P<0.025), and increase in exercise capacity was higher in MT than in T and M group (39% vs 29% and 19%). Conclusion: In pts with CAD listening to favorite music alone as well as in addition to regular exercise training, improves endothelial function. Combination of music and exercise training leads to more favorable improvement in endothelial function, expressed through higher increased of NOx, decreased of ADMA, SDMA and XO than exercise training alone. This improvement in endothelial function is associated with significant improvement in exercise capacity.

Effects of different doses of rosuvastatin on blood lipids and lipoproteins, endothelial function, and cerebral blood flow in patients with hyperlipidemia and cerebral ischemic stroke-complicated hypertension

Objective: to study the dose-dependent effect of rosuvastatin on blood lipids and lipoproteins (LP), endothelial functional activity, coagulation, and safety parameters in patients with hyperlipidemia (HLP) and hypertension after cerebral ischemic stroke (CIS). Subjects and method. The trial included 34 patients (mean age 59,4±7,4 years) with types IIa or IIb HLP and CIS-complicated hypertension. The patients were randomized to 2 groups: 1) rosuvastatin 10 mg and 2) rosuvastatin 20 mg. The trial lasted 12 weeks. The dose of rosuvastatin remained unchanged throughout the trial. The authors evaluated the impact of therapy on the blood concentration of lipids, LP, fibrinogen, end products of nitric oxide (NO) metabolism, and endothelin-1 (ET-1), cerebral blood flow by great cerebral artery Doppler ultrasound data, as well as the parameters reflecting the safety of the therapy. Results. After 12-week therapy with rosuvastatin 10 and 20 mg, there was a significant decrease in the level of cholesterol by 30 and 35%, low-density lipoprotein (LDL) cholesterol by 40 and 45%, and triglycerides by 18 and 26%, respectively. Increasing the dose of rosuvastatin was attended by a significant rise (by 18%) in the number of patients with target LDL cholesterol levels. Rosuvastatin therapy caused no changes in the high baseline level of fibrinogen. At the same time, at the rosuvastatin doses of 10 and 20 mg, the concentrations of end products of NO metabolism increased by 14,3 and 12,4%, respectively. The vasoprotective effect of rosuvastatin 20 mg showed itself just at therapy week 6. Significantly decreased ET-1 levels were found when rosuvastatin was given in a dose of 10 mg; this was directly related to the baseline concentration of ET-1. In the patients who had an ET-1 level of &gt;0,51 fmol/ml, its drop was 22,5% (p

High glucose enhances permeability of human pulmonary microvascular endothelial cells by lipopolysaccharide stimulation in vitro and effect of DDAH/NOS/NO imbalance on its pathogenesis

To investigate the damage to endothelial cells incubated in high concentration of glucose challenged by lipopolysaccharide (LPS), and the likely mechanisms of injury. Human pulmonary microvascular endothelial cells (PMVECs) were divided into the following groups: normal glucose group (NG), normal glucose + LPS stimulation group (NGL), high glucose stimulation group (HG), and high glucose + LPS stimulation group (HGL). The cells were incubated with normal glucose (5.5 mmol/L, contained 10% calf serum) or high glucose (33 mmol/L) for 5 days to form a monolayer of cells before LPS stimulation (10 mg/L) for 24 hours. The microfilaments (F-actin) were investigated by immuno-fluorescence, and the number and size change in fenestrae were examined by scanning electron microscopy. The permeability of vascular endothelial cell was assessed by trans-PMVEC horseradish peroxidase (HRP) flux. Western blotting was used to determine the expressions of dimethylarginine dimethylaminohydrolase 2 (DDAH2), inducible nitricoxide synthase (iNOS) and endothelial nitricoxide synthase (eNOS). Nitric oxide (NO) was assessed by Griess method. When stimulated with LPS, cells incubated with high glucose showed obvious microfilament rearrangement, a larger average diameter and increased number of F-actin, as well as higher HRP permeability on the hyperglycemic PMVECs compared with PMVECs cultured with normal glucose [(53.62±6.70)% vs. (23.63±3.92)%, P<0.01]. Furthermore, high glucose down-regulated DDAH2 expression (arbitrary units, AU, 0.33±0.08 vs. 0.77±0.14 , P<0.01) and up-regulated LPS-stimulated iNOS production (1.40±0.29 vs. 1.04±0.09, P<0.01), as well as increased LPS-stimulated nitrite/nitrate and stable NO end products compared with normal (20.36±2.25 μmol/L vs. 7.99±0.33 μmol/L, P<0.01) and reduction of eNOS levels was observed (0.67±0.09 vs. 0.91±0.17, P<0.05). It demonstrated that, in vitro high glucose deteriorate LPS-stimulated F-actin rearrangement and hyperpermeability of an endothelial monolayer, and the worsened imbalance of the NO pathway may lead to endothelial damage in microcirculation.

Inhibition of arginase ameliorates experimental ulcerative colitis in mice

Nitric oxide (NO) is produced from the conversion of L-arginine by NO synthase (NOS) and regulates a variety of processes in the gastrointestinal tract. Considering the increased activity of arginase in colitis tissue, it is speculated that arginase could inhibit NO synthesis by competing for the same L-arginine substrate, resulting in the exacerbation of colitis. We examined the role of arginase and its relationship to NO metabolism in dextran sulfate sodium (DSS)-induced colitis. Experimental colitis was induced in mice by administration of 2.5% DSS in drinking water for 8 days. Treatment for arginase inhibition was done by once daily intraperitoneal injection of Nω-hydroxy-nor- arginine (nor-NOHA). On day 8, we evaluated clinical parameters (body weight, disease activity index, and colon length), histological features, the activity and expression of arginase, L-arginine content, the expression of NO synthase (NOS), and the concentration of NO end-product (NOx: nitrite + nitrate). Administration of nor-NOHA improved the worsened clinical parameters and histological features in DSS-induced colitis. Treatment with nor-NOHA attenuated the increased activity of arginase, upregulation of arginase Ι at both mRNA and protein levels, and decreased the content of L-arginine in colonic tissue in the DSS-treated mice. Conversely, despite the decreased expression of NOS2 mRNA, the decreased concentration of NOx in colonic tissues was restored to almost normal levels. The consumption of L-arginine by arginase could lead to decreased production of NO from NOS, contributing to the pathogenesis of the colonic inflammation; thus, arginase inhibition might be effective for improving colitis.

Moderate Exercise Blunts Oxidative Stress Induced by Normobaric Hypoxic Confinement

Both acute hypoxia and physical exercise are known to increase oxidative stress. This randomized prospective trial investigated whether the addition of moderate exercise can alter oxidative stress induced by continuous hypoxic exposure. Fourteen male participants were confined to 10-d continuous normobaric hypoxia (FIO2 = 0.139 ± 0.003, PIO2 = 88.2 ± 0.6 mm Hg, ∼4000-m simulated altitude) either with (HCE, n = 8, two training sessions per day at 50% of hypoxic maximal aerobic power) or without exercise (HCS, n = 6). Plasma levels of oxidative stress markers (advanced oxidation protein products [AOPP], nitrotyrosine, and malondialdehyde), antioxidant markers (ferric-reducing antioxidant power, superoxide dismutase, glutathione peroxidase, and catalase), nitric oxide end-products, and erythropoietin were measured before the exposure (Pre), after the first 24 h of exposure (D1), after the exposure (Post) and after the 24-h reoxygenation (Post + 1). In addition, graded exercise test in hypoxia was performed before and after the protocol. Maximal aerobic power increased after the protocol in HCE only (+6.8%, P < 0.05). Compared with baseline, AOPP was higher at Post + 1 (+28%, P < 0.05) and nitrotyrosine at Post (+81%, P < 0.05) in HCS only. Superoxide dismutase (+30%, P < 0.05) and catalase (+53%, P < 0.05) increased at Post in HCE only. Higher levels of ferric-reducing antioxidant power (+41%, P < 0.05) at Post and lower levels of AOPP (-47%, P < 0.01) at Post + 1 were measured in HCE versus HCS. Glutathione peroxidase (+31%, P < 0.01) increased in both groups at Post + 1. Similar erythropoietin kinetics was noted in both groups with an increase at D1 (+143%, P < 0.01), a return to baseline at Post, and a decrease at Post + 1 (-56%, P < 0.05). These data provide evidence that 2 h of moderate daily exercise training can attenuate the oxidative stress induced by continuous hypoxic exposure.

Oxytocin ameliorates cisplatin-induced nephrotoxicity in Wistar rats

BACKGROUND AND OBJECTIVESThe clinical use of cisplatin (CP) is highly limited because of its renal toxicity and the production of reactive oxygen species (ROS) that intensify the cytotoxic effects. Oxytocin (OT) was previously shown to have antioxidant activity.DESIGN AND SETTINGExperimental study on male Wistar albino rats performed in the Faculty of Pharmacy, King Abdulaziz University, Jeddah, Saudi Arabia.METHODSForty-eight male Wistar albino rats were classified into four equal groups: a control group, OT only-treated group which received OT twice (500 μg/kg intraperitoneally (ip) 30 minutes and just before saline administration), a CP-induced nephrotoxicity group that received a single dose of CP (7.5 mg/kg ip) and treated with saline, and CP+OT group treated with the same previous doses. Seventy-two hours after CP administration, the rats were sacrificed and blood was withdrawn for determination of urea, creatinine, albumin and lactate dehydrogenase (LDH). The kidneys were extracted for histopathological examination and determination of the tissue levels of reduced glutathione (GSH), thiobarbituric acid reactive substances (TBARS) and nitric oxide end product nitrite (NO2). Glutathione S-transferase (GST), catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx) and myeloperoxidase (MPO) activities were assessed.RESULTSCP-induced renal injury was evidenced histopathologically and manifested by a significant increase in serum LDH activity as well as urea and creatinine levels. Moreover, renal injury was associated with decreased renal tissue activities of CAT, SOD, GPx and GST as well as GSH level. On the other hand, renal tissue content of TBARS and NO2 as well as the activity of MPO were increased. Alterations in these biochemical and histopathological indices due to CP were attenuated by OT.CONCLUSIONOT protected rats from CP-induced nephrotoxicity. Such protection is attributed, at least in part, to its antioxidant activity.

Interaction between Advanced Glycation End Products Formation and Vascular Responses in Femoral and Coronary Arteries from Exercised Diabetic Rats

BackgroundThe majority of studies have investigated the effect of exercise training (TR) on vascular responses in diabetic animals (DB), but none evaluated nitric oxide (NO) and advanced glycation end products (AGEs) formation associated with oxidant and antioxidant activities in femoral and coronary arteries from trained diabetic rats. Our hypothesis was that 8-week TR would alter AGEs levels in type 1 diabetic rats ameliorating vascular responsiveness.Methodology/Principal FindingsMale Wistar rats were divided into control sedentary (C/SD), sedentary diabetic (SD/DB), and trained diabetic (TR/DB). DB was induced by streptozotocin (i.p.: 60 mg/kg). TR was performed for 60 min per day, 5 days/week, during 8 weeks. Concentration-response curves to acetylcholine (ACh), sodium nitroprusside (SNP), phenylephrine (PHE) and tromboxane analog (U46619) were obtained. The protein expressions of eNOS, receptor for AGEs (RAGE), Cu/Zn-SOD and Mn-SOD were analyzed. Tissues NO production and reactive oxygen species (ROS) generation were evaluated. Plasma nitrate/nitrite (NOx −), superoxide dismutase (SOD), catalase (CAT), thiobarbituric acid reactive substances (TBARS) and Nε-(carboxymethyl) lysine (CML, AGE biomarker). A rightward shift in the concentration-response curves to ACh was observed in femoral and coronary arteries from SD/DB that was accompanied by an increase in TBARS and CML levels. Decreased in the eNOS expression, tissues NO production and NOx − levels were associated with increased ROS generation. A positive interaction between the beneficial effect of TR on the relaxing responses to ACh and the reduction in TBARS and CML levels were observed without changing in antioxidant activities. The eNOS protein expression, tissues NO production and ROS generation were fully re-established in TR/DB, but plasma NOx − levels were partially restored.ConclusionShear stress induced by TR fully restores the eNOS/NO pathway in both preparations from non-treated diabetic rats, however, a massive production of AGEs still affecting relaxing responses possibly involving other endothelium-dependent vasodilator agents, mainly in coronary artery.

Mirtazapine protects against cisplatin‐induced oxidative stress and DNA damage in the rat brain

Cisplatin chemotherapy is associated with neurotoxicity, and oxidative stress might play an important role in the pathogenesis. Mirtazapine may be a preventative agent via its less-known antioxidant properties. The aim of this study was to examine the potential chemoprotective effects of mirtazapine against cisplatin-induced oxidative stress and DNA damage. Twenty-four rats were divided equally into four groups: control; cisplatin (10 mg/kg i.p.); cisplatin plus mirtazapine (10-30 mg/kg, respectively i.p and p.o.); and mirtazapine (30 mg/kg p.o.). The rats were killed at the end of the 14th day of treatment. Brain tissue was examined with regard to antioxidant/oxidant biochemical parameters. Although glutathione (tGSH) and nitric oxide (NO) end product mean scores were found to be statistically higher in the control group when compared with the cisplatin group (72.44% and 61.99% percentage change [PC], respectively), malondialdehyde (MDA), myeloperoxidase (MPO), and 8-hydroxyguanine (8-OH-GUA) mean scores were statistically lower in the control group in comparison with the cisplatin group (-55.48%, -67.99%, and -48.81% PC, respectively; P < 0.01). Finally, tGSH and NO end product levels were restored to normal (85.90% and 55.30% PC, respectively), and MDA, MPO, and 8-OH-GUA were significantly reduced by treatment with mirtazapine (-60.50%, -78.59%, and -38.10% PC, respectively; P < 0.01). Mirtazapine has chemoprotective effects against cisplatin-induced oxidative stress and DNA damage in the rat brain, which may be attributed to its antioxidant capabilities. It would be useful to investigate whether cisplatin at the desired doses can be given concurrently with mirtazapine.

Exhaled breath condensate nitric oxide end products and pH in controlled asthma

ObjectivesAsthma imposes a growing burden on the society in terms of morbidity, quality of life, and healthcare costs. It has the highest morbidity amongst inflammatory lung diseases and its prevalence continues to increase over the world. Inquiry into recent day or nighttime symptoms alone underestimates the burden of asthma and may lead to inadequate treatment of asthma. The aim of the present work is to evaluate the role of nitric oxide (NO) and hydrogen ion concentration (pH) levels in exhaled breath condensate (EBC) in cases of controlled bronchial asthma. Patients and methodsThe present study was conducted on 49 controlled asthmatic patients and 12 control subjects. All patients were subjected to thorough history taking, complete clinical examination and plain postero-anterior chest X-ray. All asthmatics and control subjects were subjected to routine laboratory investigations, spirometric study, EBC collection, processing and analysis for its content of both nitric oxide end products: nitrite and nitrate (NOx) and pH. ResultsAll asthmatics represented Group IT which was further divided into Group Ia: 34 patients on regular inhaled corticosteroid (ICS) therapy and Group Ib: 15 patients on no regular therapy. The control subjects represented Group II. The forced vital capacity (FVC), forced expiratory volume in the first second (FEV1), FEV1/FVC, peak expiratory flow rate (PEFR) and forced expiratory flow during the middle portion of a forced expiration (FEF 25–75%) were significantly lower in asthmatics than control subjects. The EBC-NOx mean±SD in μmol/L in Group IT (5.99±1.63), in Group Ia (5.27±1.26) and in Group Ib (7.63±1.15) were significantly higher than in Group II (3.66±0.67) with, respectively (p=0.000), (p=0.000) and (p=0.000); and was significantly higher in Group Ib than Group Ia (p=0.000). The EBC-pH mean±SD in Group IT (7.32±0.27), in Group Ia (7.35±0.25) and in Group Ib (7.27±0.3) were significantly lower than in Group II (7.82±0.09) with, respectively (p=0.000), (p=0.000) and (p=0.000); with no significant difference between Group Ia and Group Ib. The EBC-NOx was significantly directly correlated to eosinophils count (p=0.017) and neutrophils count (p=0.002); and inversely correlated to FEV1 (p=0.016), FEV1/FVC (p=0.001), PEFR (p=0.030) and EBC-pH (p=0.003). The EBC-pH was significantly inversely correlated to eosinophils count (p=0.017) and neutrophils count (p=0.036); and directly correlated to FVC (p=0.004), FEV1 (p=0.004) and PEFR (p=0.000). ConclusionEBC-NOx is significantly higher and EBC-pH is significantly lower in asthmatic patients than in control subjects. Asthmatics receiving ICS have a lower EBC-NOx level than those not. EBC-NOx and EBC-pH were significantly correlated and both of them showed significant correlations with spirometric parameters of airway obstruction.

Dietary Phosphatidylcholine Supplementation Attenuates Inflammatory Mucosal Damage in a Rat Model of Experimental Colitis

This study was designed to follow the time course of inflammatory activation in a rodent model of 2,4,6-trinitrobenzenesulfonic acid (TNBS)-induced colitis. We hypothesized that oral phosphatidylcholine (PC) pretreatment regimens may influence leukocyte-mediated microcirculatory reactions in this condition. In series I, Wistar rats were monitored 1 day after colitis induction (n = 24), and in series II (n = 24) on day 6 following a TNBS enema. The PC-pretreated animals received a 2% PC-enriched diet for 6 days before the TNBS enema (series I), or for 3 days before and 3 days after TNBS treatment (series II). The macrohemodynamics, serosal microcirculation (visualized by intravital videomicroscopy), colonic xanthine oxidoreductase, myeloperoxidase and nitric oxide end products, and changes in proinflammatory cytokine levels in plasma were measured. The mucosal structural injury was monitored in vivo by means of confocal laser scanning endomicroscopy. The TNBS enema induced a systemic hyperdynamic circulatory reaction with increased serosal capillary blood flow and significantly elevated colonic inflammatory enzyme activities, levels of nitric oxide production, and cytokine concentrations. Acute colitis caused disruption of the capillary network, whereas the morphologic damage was less severe in series II. The PC pretreatment protocols led to significant decreases in the serosal hyperemic reaction, the cytokine levels, and the inflammatory enzyme activities. The objective signs of tissue damage were reduced in both series, and the number of mucus-producing goblet cells in the resolving phase of colitis was increased. Dietary PC efficiently decreases the cytokine-mediated progression of inflammatory events and preserves the microvascular structure in the large intestine.