Ceyda Kabaroglu

Effect of different levels of cigarette smoking on lipid peroxidation, glutathione enzymes and paraoxonase 1 activity in healthy people.

The purpose of this study was to examine the effect of different levels of cigarette smoking on lipid peroxidation, glutathione enzymes and paraoxonase 1 (PON1) activity in a healthy population. The study included 130 subjects who were classified as mild (≤10 cigarettes daily, Group I, n=30), moderate (11–20 cigarettes daily, Group II, n=35), heavy (>20 cigarettes daily, Group III, n=33) and never smokers (controls, Group IV, n=32). Malondialdehyde (MDA) levels, PON1 and erythrocyte glutathione enzyme activities were measured. MDA levels were significantly higher in smokers than never smokers (P<0.05 for Group I, P<0.001 for Group II and III). PON1 activity was significantly lower in heavy smokers (P<0.001). Glutathione peroxidase (GSH-Px) activity was significantly lower in the smokers (P<0.0001). Glutathione reductase (GR) activity was significantly higher in smokers (P<0.0001). MDA levels negatively correlated with PON1 and GSH-PX activities (P<0.01), whereas they positively correlated with GR activities (P<0.001). At every level, cigarette smoking is associated with increased lipid peroxidation and causes an impairment in antioxidant systems.

Association between serum paraoxonase activity and oxidative stress in acute coronary syndromes.

Objective — The oxidation of low-density lipoprotein (LDL) is believed to have a central role in atherogenesis. Under oxidative stress not only LDL, but all other serum lipids are exposed to oxidation. High-density lipoprotein (HDL)-associated paraoxonase (PON1) was shown to inhibit LDL and HDL oxidation.We investigated the relationship between PON1 and oxidative stress in acute myocardial infarction and unstable angina in a comparative fashion. Methods and results — Activities of PON1, concentrations of malondialdehyde (MDA), lipids and lipoproteins were measured in patients (38 subjects with acute myocardial infarction and 33 subjects with unstable angina pectoris) and in age- and sex-matched controls (32 subjects). Serum PON1 activity was significantly lower in patients than in controls (p < 0.001). Patients had significantly increased serum MDA concentrations (p < 0.001) and there were strong negative correlations (p < 0.001) between serum PON1 and MDA levels in the acute myocardial infarction group (r = –0.673), in the unstable angina pectoris group (r = –0.868) and in healthy controls (r = –0.778). Serum HDL-cholesterol (HDL-C) concentrations were lower in patients than controls (p < 0.05). No correlation was observed between PON1 and HDL-C levels in patients or controls. Apo A I concentrations were significantly lower in the patient groups (p < 0.01), but were insignificant between patients with AMI and UAP. Apo A-I and PON1 levels did not show any correlation. Apo B concentrations were lowest in the healthy controls, higher in the UAP group and highest in the AMI group (p < 0.001). In the acute myocardial infarction group LDL/apo B ratio was lower than in healthy controls and in the UAP group, suggesting smaller LDL particle size. Conclusions — Results of this study indicate that lower serum PON1 activity is associated with oxidative stress and the activity of PON1 is not related to HDL-cholesterol.

The beneficial effects of physical exercise on antioxidant status in asthmatic children

BACKGROUND The pathogenesis of asthma involves both airway inflammation and an oxidant/antioxidant imbalance. It is demonstrated in asthmatic adults that exercise programmes improve lung function, a mechanism yet to be elucidated. The purpose of this study was to investigate the possible beneficial effects of physical exercise on antioxidant status in asthmatic children which may lead to ameliorated lung function. METHODS The study enrolled thirteen control and thirty asthmatic children. The asthmatic group was subdivided into two: the first group receiving only pharmacological treatment (n=15) and the second receiving pharmacological treatment with exercise programme (n=15) for 8 weeks. Blood samples were drawn from the subjects before and after treatment periods. As oxidant stress markers blood levels of malondialdehyde (MDA) and total nitric oxide (NO), and as antioxidant status, glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) enzyme activities were assessed. RESULTS Before any treatment was initiated, MDA and NO levels in the asthmatic group were significantly higher than the controls (3.40±0.96 nmol/ml vs 2.46±0.58 nmol/ml, and 12.53±2.10 vs 9.40±1.39 micromol/L, respectively). Both SOD (p=0.0001) and GSH-Px (p=0.023) activities were significantly lower in the asthmatic group. Pharmacological treatment and exercise programme together significantly improved lung performance and decreased the levels of oxidant stress markers, in concordance with a significantly increase in antioxidant enzyme activity measures when compared to the pharmacological treatment. CONCLUSION Structured exercise programme in asthmatic children resulted in better lung function, which may be attributed to its effect on antioxidant status.

Effects of the Calcium Channel Blocker Amlodipine on Serum and Aortic Cholesterol, Lipid Peroxidation, Antioxidant Status and Aortic Histology in Cholesterol-Fed Rabbits

Reactive oxygen metabolites and oxidized fatty acids are proinflammatory and are involved in the pathophysiology of atherosclerosis. Amlodipine, a unique third-generation dihydropyridine-type calcium channel blocker, seems to exert atheroprotective effects through its antioxidant properties related to its chemical structure and independent of its calcium channel-blocking effect. In this study, the interactions of amlodipine with major cellular antioxidants were investigated in order to elucidate the mechanisms underlying its atheroprotective effects. New Zealand white male rabbits were fed regular chow (group 1), chow with 1% cholesterol (group 2), regular chow plus 5 mg/kg/day amlodipine per os (group 3) and 1% cholesterol plus amlodipine (group 4) for 8 weeks. Total cholesterol, malondialdehyde (MDA) and vitamin E concentrations and catalase and superoxide dismutase (SOD) activities were determined in blood drawn before and after the experimental period. Aortic tissue was examined for atherosclerotic changes and aortic total cholesterol, MDA, catalase and SOD were determined. At the end of the 8-week treatment period, serum total cholesterol and plasma MDA were elevated in groups 2 and 4. In group 2, serum vitamin E and plasma SOD diminished (p < 0.05) and catalase increased (p < 0.05). In group 4, SOD activity increased at the end of treatment. MDA levels were lower and plasma SOD activities were higher in group 4 than in group 2. Aortic tissue investigations revealed higher total cholesterol and MDA concentrations and catalase activities in group 2 than in group 4, and the highest tissue SOD activity was recorded in group 4 (p < 0.05 for all comparisons). Morphological examination of aortic tissues exhibited endothelial disarrangement and lipid deposition in group 2. Histopathological alterations related to atherogenesis were less in group 4 than in group 2. Amlodipine seems to exert atheroprotective effects by reducing aortic cholesterol accumulation and blood and aortic lipid peroxidation, enhancing SOD activity both in blood and aortic tissue and suppressing the consumption of vitamin E. On the other hand, the suppression of catalase activity in blood and the aorta interferes with the drugs well-known antioxidant effects.

Oxidative stress impairs endothelial nitric oxide levels in Behçets’ disease

Background: Behçet’s disease (BD) is an inflammatory vasculitis. Endogenous nitric oxide (NO), produced by endothelial cells, has pleiotropic effects such as vasodilatator, antiplatelet, antiproliferative. Reactive oxygen species (ROS) are produced at sites of endothelial inflammation. ROS target polyunsaturated lipids, which results in malondialdehyde (MDA) production. Objective: The aim was to investigate the oxidative stress in BD patients by measuring MDA and total antioxidant status (TAS) levels and to establish a possible relationship with respect to NO levels regarding disease activity. Materials and methods: 55 BD patients (30 active/25 inactive) and 20 healthy volunteers were included in the study. Blood samples were drawn following an overnight fasting. TAS and MDA levels were determined spectrophotometrically. Serum nitrite (NO2−) and nitrate (NO3−) levels were measured to estimate NO production. Data were expressed as mean ± SD. Results: TAS levels were significantly lower in BD patients than the controls (1.19 ± 0.34 vs. 3.29 ± 0.89 mmol/L). In the active BD group, MDA levels (0.36 ± 0.19 nmol/mL) were significantly higher than both the inactive BD group (0.25 ± 0.18 nmol/mL) and controls (0.18 ± 0.41 nmol/mL). NO levels were significantly lower in the active group compared to the inactive group (18.0 ± 2.80 vs. 19.40 ± 2.70 µmol/L). MDA levels correlated negatively with NO levels in the active group. Conclusion: Decreased NO levels mediated by increased oxidative stress significantly contribute to endothelial dysfunction observed in BD.

Nitric oxide and oxidative stress in atherosclerotic renovascular hypertension: effect of endovascular treatment.

PURPOSE Because activation of the renin-angiotensin system leads to an increase in oxidative stress, the authors investigated nitric oxide (NO; nitrite + nitrate), superoxide dismutase (SOD), catalase, and malondialdehyde (MDA) levels and the effect of endovascular treatment on these parameters in patients with atherosclerotic renovascular hypertension. The relationship of NO with blood pressure and renal functional indexes was also investigated. MATERIALS AND METHODS In this prospective cohort study, serum creatinine, NO, SOD, catalase, plasma MDA, urinary microalbumin, and NO levels, and blood pressure were determined in 21 patients with hypertension and unilateral renal artery stenosis caused by atherosclerosis at entry and after 24 hours, 2 weeks, and 6 weeks of endovascular treatment. RESULTS MDA concentrations decreased 24 hours after intervention and remained low 2 and 6 weeks later. In addition, serum SOD and NO and urine NO levels were increased significantly 24 hours after endovascular treatment and decreased after 2 and 6 weeks. However, serum catalase levels did not differ after the intervention. Blood pressures decreased after treatment. There were no significant differences in urinary microalbumin levels, estimated glomerular filtration rates, and creatinine levels after endovascular treatment. CONCLUSIONS Endovascular treatment decreases oxidative stress and may offer new benefits in the treatment of patients with hypertension associated with renal artery stenosis. The decrease in oxidative stress and/or the upregulation of SOD may increase the bioavailability of NO, which in turn may lead to the rapid hypotensive response.

C-Reactive protein and neopterin levels in healthy non-obese adults

Abstract Background: Obesity and increased waist-to-hip ratio, emphasizing the importance of truncal obesity, have been found to correlate positively with increased cardiovascular disease risk and mortality. Owing to the inflammatory nature of atherosclerosis, the aim of our study was to find possible correlations between body mass index and waist-to-hip ratio, and the inflammatory markers C-reactive protein (CRP) and neopterin in healthy lean and overweight adults. Methods: A total of 49 healthy adults (mean age 42.4±1.8years, 32 females and 17 males) were classified according to their body mass index (BMI) and waist-to-hip ratio values. CRP and neopterin levels were measured. Results: CRP levels were found to be significantly higher in the group with BMI≥25kg/m2 compared to the group with BMI<25kg/m2 (p=0.014). Subjects with increased waist-to-hip ratio displayed significantly higher serum CRP and neopterin levels (p=0.014 and p=0.033, respectively) compared with the group in which the waist-to-hip ratio was <0.9. A strong positive correlation was found between CRP and BMI in the whole group (r=0.658, p=0.0001). Conclusions: Grouping overweight subjects according to their waist-to-hip ratio, which is an indicator of truncal obesity, seems to be convenient in studying the inflammatory process in relation to the elevation of adipose tissue. Elevated CRP and neopterin levels may be useful in the assessment of cardiovascular risk in overweight as well as obese subjects.

Effects of L‐arginine and L‐carnitine in hypoxia/reoxygenation‐induced intestinal injury

Abstract  Background : This study was designed to show the role of oxidative stress, nitric oxide and glutathione‐related antioxidant enzymes in hypoxia/reoxygenation (H/R)‐induced intestinal injury model in mice and to evaluate the potential benefits of arginine and carnitine supplementation.

Do cardiac risk factors affect the homocysteine and asymmetric dimethylarginine relationship in patients with coronary artery diseases

OBJECTIVES Elevated homocysteine (Hcy) concentrations have been shown to be a risk factor for atherosclerotic vascular disease and thrombosis. Increased asymmetric dimethylarginine (ADMA) levels have been implicated in the pathogenesis of numerous conditions affecting the cardiovascular system. In this study, the influence of cardiovascular risk factors and other variables on Hcy and ADMA relationship in patients with coronary artery disease (CAD) was investigated. DESIGN AND METHODS Seventy-five patients with CAD were divided into three tertiles according to their Hcy levels. The effect of age, gender, blood pressure, lipid profile, renal function, and the presence of diabetes, insulin resistance, heart failure, inflammation, overweight, smoking and severity of coronary atherosclerosis on Hcy and ADMA relationship was evaluated. RESULTS ADMA concentrations of patients in the middle and highest Hcy tertiles were significantly higher than the patients in the lowest tertile. When ADMA concentrations were adjusted for demographic, clinical and laboratory variables, the significant differences in ADMA concentrations between the tertiles were preserved. ADMA levels positively correlated with Hcy. Homocysteine levels positively correlated with serum creatinine and NT-proBNP concentrations and negatively correlated with glomerular filtration rates. Stepwise multiple regression analysis revealed Hcy as the unique predictor of ADMA levels. CONCLUSION Homocysteine concentration has an effect on ADMA levels. There is a strong correlation between Hcy and ADMA. Cardiovascular risk factors do not have an influence on this relationship.

Inflammatory marker levels in obese adolescents with glucose intolerance: Increased chitotriosidase activity

OBJECTIVES Existence of low grade persistent inflammation in obese children may increase the risk of metabolic and cardiovascular events. The aim was to determine whether glucose intolerance has an influence on inflammatory markers in obese adolescents. DESIGNS AND METHODS 45 obese adolescents (mean BMI: 30.34±5.42 kg/m²) were grouped as normal or impaired glucose tolerance. IL-6 and CRP levels were analyzed by commercially available kits. Chitotriosidase activity was measured by a fluorescence method and neopterin levels were determined by ELISA. Data were expressed as mean±SD. RESULTS IL-6 and CRP levels were similar in the two groups. Serum neopterin levels were not different between the groups. The chitotriosidase activity was significantly higher in the IGT group than NGT (124.33±51.97 μmol/L/h vs 84.50±53.99 μmol/L/h, p=0.04). CONCLUSION Serum chitotriosidase activity is increased in obese adolescents with impaired glucose tolerance.