Plasma Oxidative Stress Markers Research Articles

Estimation of Oxidative Stress Markers in Chronic Kidney Disease

Changes mediated by oxidative stress are thought to be involved with atherosclerosis in patients with chronic kidney disease (CKD). The purpose of this study was to analyze the markers of oxidative damage and the activity of antioxidative enzymes as well as the total antioxidant capability in patients with different stages of CKD, both conventionally treated and dialyzed. We evaluated the oxidative modification of lipids (by oxidized low-density lipoprotein and malonodialdehyde levels) and proteins (by advanced oxidation protein products level). We also assessed the activity of paraoxonase-1 and glutathione peroxidases and total antioxidant status. Compared with the control group, the uremic patients, both dialyzed and nondialyzed, had higher levels of all studied plasma oxidative stress markers and decreased activity of antioxidative enzymes. Our results lead us to conclude that oxidative stress seems to be related rather to the uremic state than to the dialysis treatment. We also showed that estimating total antioxidant status in a simple test is unreliable for assessing the antioxidant ability of patients with CKD.

Diet-supported aerobic exercise reduces blood endothelin-1 and nitric oxide levels in individuals with impaired glucose tolerance

Impaired glucose tolerance (IGT) forms an intermediate stage in the natural history of diabetes mellitus. Insulin-resistant states might be associated with dysfunction of the vascular endothelium. To determine the effects of chronic exercise and a low-calorie diet on plasma nitric oxide (NO) and endothelin-1 (ET-1) levels in patients with IGT and to elucidate the relationship between the oxidant stress markers and NO/ET-1 levels of blood before and after exercise. Patients with IGT (n = 14) participated in a regular exercise program and exercised for 40 minutes each day, 3 days a week for 12 weeks. Physiological, anthropometric, and biochemical measurements were performed before, during the 6th week, and at the end of the program. There was a significant reduction in body mass index, body fat content, systolic and diastolic blood pressures, as well as NO and ET-1 concentrations after 12 weeks of exercise and diet program. Exercise training significantly elevated subjects' maximum oxygen consumption, whereas the resting metabolic rates of the patients did not change. The formation of thiobarbituric acid reactive substances were significantly reduced, whereas sulfhydryl groups were significantly increased on the 6th week (P < .05) and at the end of program (P < .01). Our results demonstrate that exercise, along with low-calorie diet, induced reductions in the plasma of both ET-1 and NO. Beneficial effects were observed on anthropometric measurements and plasma oxidant stress markers, indicating weight loss associated with exercise training and calorie restriction may effectively improve endothelial dysfunction in patients with IGT.

Comparison of purple carrot juice and β-carotene in a high-carbohydrate, high-fat diet-fed rat model of the metabolic syndrome

Anthocyanins, phenolic acids and carotenoids are the predominant phytochemicals present in purple carrots. These phytochemicals could be useful in treatment of the metabolic syndrome since anthocyanins improve dyslipidaemia, glucose tolerance, hypertension and insulin resistance; the phenolic acids may also protect against CVD and β-carotene may protect against oxidative processes. In the present study, we have compared the ability of purple carrot juice and β-carotene to reverse the structural and functional changes in rats fed a high-carbohydrate, high-fat diet as a model of the metabolic syndrome induced by diet. Cardiac structure and function were defined by histology, echocardiography and in isolated hearts and blood vessels; liver structure and function, oxidative stress and inflammation were defined by histology and plasma markers. High-carbohydrate, high-fat diet-fed rats developed hypertension, cardiac fibrosis, increased cardiac stiffness, endothelial dysfunction, impaired glucose tolerance, increased abdominal fat deposition, altered plasma lipid profile, liver fibrosis and increased plasma liver enzymes together with increased plasma markers of oxidative stress and inflammation as well as increased inflammatory cell infiltration. Purple carrot juice attenuated or reversed all changes while β-carotene did not reduce oxidative stress, cardiac stiffness or hepatic fat deposition. As the juice itself contained low concentrations of carotenoids, it is likely that the anthocyanins are responsible for the antioxidant and anti-inflammatory properties of purple carrot juice to improve glucose tolerance as well as cardiovascular and hepatic structure and function.

Plasma markers of oxidative stress, inflammation and endothelial cell injury in diabetic patients with overt nephropathy administered alpha-lipoic acid and angiotensin II receptor blocker

Alpha-lipoic acid (ALA) is a natural antioxidant that scavenges reactive oxygen species (ROS) and regenerates endogenous antioxidants. In the present study, plasma molecular markers of oxidative stress, inflammatory state, and endothelial cell injury was measured to investigate the effect of simultaneous blocking of both angiotensin (AT) II-and oxidative stress-mediated pathophysiologic pathways during the course of type II diabetic nephropathy in the clinical settings. Sixty-three diabetic subjects have carried out either of 12-month treatment course of AT-II receptor blocker (ARB) alone, ALA alone, or combination of both. Plasma malondialdehyde (MDA) level, a marker for oxidative stress, increased in ARB alone group whereas reduced to significantly lower level in ALA+ ARB combination group. Plasma hs-CRP level, an inflammatory marker, decreased significantly in ARB +ALA group. Plasma thrombomodulin (TM) level, a marker of endothelial cell injury, increased in both ARB and ALA group. Twenty-four hour urinary protein excretion, as a marker of renal injury, decreased in ARB and ARB+ALA group. Finally, renal function was reserved well in ARB+ALA group in compared to others. The combined administration of ALA and ARB additively attenuated or reduced plasma markers of oxidative stress, inflammation and endothelial cell injury for one year. It suggests that the benefits in attenuating atherogenic process and vascular injury retard the progression of renal dysfunction.

Circulating Biomarkers Of Nitro-oxidative Stress In Young And Older Active And Inactive Men

Title: CIRCULATING BIOMARKERS OF NITROOXIDATIVE STRESS IN YOUNG AND OLDER ACTIVE AND INACTIVE MEN Lori Beth Bjork, M.A., 2010 Directed By: Professor James M. Hagberg, PhD Department of Kinesiology Oxidative stress markers may be novel factors contributing to cardiovascular (CVD) risk. The purpose of this study was to examine the effects of long-term exercise, age, and their interaction on the plasma levels of the oxidative stress markers oxidized LDL (ox-LDL), nitrotyrosine, and myeloperoxidase (MPO), and to investigate whether these levels correlated with plasma NOx levels. Older (62 ± 2 yr) active (n=12) men who had exercised regularly for over 30 years and young (25 ± 4 yr) active (n=7) men who had exercised regularly for over 3 years were matched to older (n=11) and young (n=8) inactive males. Young subjects showed lower plasma nitrotyrosine levels than older subjects (P = 0.047). Young inactive subjects had higher ox-LDL levels than either the young active (P = 0.042) or the older active (P = 0.041) subjects. In addition, plasma oxidative stress levels, particularly ox-LDL, were correlated with various conventional CVD risk factors, and in older subjects were associated with Framingham risk score (r = 0.49, P = 0.015). The study found no relationships between plasma markers of oxidative stress and plasma NOx levels. The findings suggest that a sedentary lifestyle may be associated with higher ox-LDL levels and that the levels of oxidative stress markers may contribute to CVD risk. CIRCULATING BIOMARKERS OF NITRO-OXIDATIVE STRESS IN YOUNG AND OLDER ACTIVE AND INACTIVE MEN

Effect of Oral N-Acetylcysteine Treatment on Plasma Inflammatory and Oxidative Stress Markers in Peritoneal Dialysis Patients: A Placebo-Controlled Study

Inflammation and oxidative stress (OS) are cardiovascular risk factors in patients with chronic kidney disease. N-acetylcysteine (NAC) is a thiol-containing antioxidant with anti-inflammatory properties and has been shown to reduce the number of cardiovascular events in hemodialysis patients. The current study aimed to determine the effect of oral NAC (2 x 600 mg/daily) on plasma levels of inflammatory and OS markers in peritoneal dialysis (PD) patients. We performed a placebo-controlled study over 8 weeks in 30 patients (40% males, age 52 +/- 13 years) on regular PD. Before the study was started, the patients were divided into 2 groups of 15 patients matched for age and gender. 22 patients completed the study (12 on NAC, 10 on placebo). Proinflammatory cytokines [high-sensitivity C-reactive protein, interleukin-6 (IL-6), tumor necrosis factor-alpha, and pentraxin 3] and markers of OS (pentosidine, advanced oxidation protein products, homocysteine, glutathione, asymmetric dimethylarginine, and free sulfhydryls) were measured before and after treatment with NAC. Treatment with NAC for 8 weeks increased mean baseline plasma NAC levels from 2.6 to 24.8 mumol/L (p = 0.007). This intervention, which caused no side effects, significantly diminished IL-6 levels, from 9.4 (4.5 - 31) to 7.6 (4.9 - 13.5) pg/mL (p = 0.006), whereas no such changes were observed in the placebo group. NAC treatment did not significantly affect the other inflammatory and OS markers. Short-term oral NAC treatment resulted in reduction of circulating IL-6, suggesting that such treatment could be a useful strategy in blunting the inflammatory response in PD patients.

Regular Grape Intake Reduces Cardiac and Renal Dysfunction and Metabolic Syndrome in Obesity‐Prone Rats

Metabolic Syndrome is characterized by increased systemic inflammation, abdominal fat, high triglycerides, low HDL, hypertension, and insulin resistance. The presence of some or all of these risk factors predisposes one to Type II diabetes and cardiovascular disease. Epidemiologic studies suggest that higher intake of fruits/vegetables could modify risk factors for metabolic syndrome. Phytochemicals may be vital to the observed health effects. Grapes are a rich, whole‐food source of phytochemicals. In the obesity‐prone Zucker Fatty rat, we tested the effect of a higher fat diet(45% kcal) with added whole table grape powder(3% w:w). Rats were fed for 90 days. Compared to a macronutrient and calorie‐matched control group, the grape diet had no significant effect on body weight or DEXA‐determined body composition. Grape intake reduced blood pressure and proteinuria while improving cardiac output. The grape‐fed group had reduced heart weight, kidney weight, and liver weight. The grape‐fed animals had reduced fasting serum triglycerides and hyperinsulinemia but not total cholesterol(p=0.12). Finally, grape intake reduced plasma inflammatory markers C‐reactive protein, TNF‐α and IL‐6, and reduced plasma oxidative stress marker 8‐isoprostane. The results suggest that regular intake of grapes reduced several risk factors for cardiovascular disease and metabolic syndrome.

Relationships of Plasma Homocysteine Concentration and Oxidative Stress Markers in Korean Collage Students

Elevated plasma concentration of total homocysteine (ptHcy) is known as an independent risk factor of cardiovascular disease (CVD) and oxidative stress is also commonly implicated in CVD. An association between ptHcy and oxidative stress has recently been suggested. The study objective is to examine the relationship between ptHcy and oxidative stress markers in 103 healthy college students (62 males and 41 females). Plasma levels of ptHcy, oxidative stress markers (conjugated diene, erythrocyte catalase, TRAP, lymphocyte DNA damage), antioxidant vitamins (α-tocopherol, γ-tocopherol, carotenoids), and lipid parameters (total cholesterol, triglyceride, HDL cholesterol) were determined. The results show that the concentration of ptHcy was significantly higher in male subjects (22.17 ± 2.14 μmole/L) than in female subjects (12.28 ± 0.45 μmole/L). There was a negative association between ptHcy and plasma βcarotene in male subjects (p < 0.05), but no correlation between ptHcy and other plasma antioxidant vitamin levels in either gender. However, there were the negative correlations between ptHcy and plasma α-carotene or β-carotene, and a positive correlation between ptHcy and lymphocyte DNA damage. A significantly low level of α-carotene or β-carotene was found in male subjects with elevated ptHcy (≥ 15 μmol/L), as compared to those with lower plasma homocysteine. These study results confirmed the views on the association between plasma homocysteine and oxidative stress markers in humans and support the hypothesis that homocysteine promotes the oxidative environment by counteracting the antioxidant defense mechanism. (Korean J Nutr 2010; 43(5): 443 ~ 452)

262 Are Zucker Obese Rats a Useful Model for Cardiovascular Complications in Metabolic Syndrome? Physical, Biochemical and Oxidative Stress Considerations

We wondered if Zucker obese (ZO) rats would be a good experimental model to evaluate cardiovascular complications of Metabolic Syndrome (MS). ZO rats were compared with both their littermate controls, Zucker lean (ZL) rats and to Wistar rats (reference strain). We designed this work 1) to measure certain physical and biochemical characteristics of MS 2) to evaluate coronary and cardiac function in isolated conditions and after ischemia 3) to study plasma and heart tissue oxidative stress markers. In vivo, ZO rats had higher levels of plasma glucose, cholesterol and triglycerides than their ZL littermates, but there was no difference between the groups for systolic arterial blood pressure and heart rate. In vitro, coronary endothelial function was notably impaired in ZO and ZL rats. After global ischemia, the worse ventricular recovery in ZO and ZL rats was associated with arrhythmias during reperfusion. We detected similar levels of plasma ascorbyl free radical, Oxygen Radical Absorbance Capacity and vitamin C concentrations in the three groups. DHE staining showed higher superoxide production in the coronary vessels of ZO rats than in ZL and Wistar rats. Our results show that ZO might only correspond to early-stage cardiovascular complications associated with MS.

Early alterations in vascular contractility associated to changes in fatty acid composition and oxidative stress markers in perivascular adipose tissue

AimTo test the early effect of fructose-induced changes in fatty acid composition and oxidative stress markers in perivascular adipose tissue (PVAT) upon vascular contractility.MethodsAdult male Wistar rats were fed a commercial diet without (CD) or with 10% fructose (FRD) in the drinking water for 3 weeks. We measured plasma metabolic parameters, lipid composition and oxidative stress markers in aortic PVAT. Vascular contractility was measured in aortic rings sequentially, stimulated with serotonin (5-HT) and high K+-induced depolarization using intact and thereafter PVAT-deprived rings.ResultsComparable body weights were recorded in both groups. FRD rats had increased plasma triglyceride and fructosamine levels. Their PVAT had an increased saturated to mono- or poly-unsaturated fatty acid ratio, a significant decrease in total superoxide dismutase and glutathione peroxidase activities and in the total content of glutathione. Conversely, lipid peroxidation (TBARS), nitric oxide content, and gluthathione reductase activity were significantly higher, indicating an increase in oxidative stress. In aortic rings, removal of PVAT increased serotonin-induced contractions, but the effect was significantly lower in rings from FRD rats. This effect was no longer observed when the two contractions were performed in PVAT-deprived rings. PVAT did not affect the contractions triggered by high K+-induced depolarization either in CD or FRD rats.ConclusionsFRD induces multiple metabolic and endocrine systemic alterations which also alter PVAT and the vascular relaxant properties of this tissue. The changes in PVAT would affect its paracrine modulation of vascular function.

Effect of rosuvastatin on concentrations of plasma lipids, urine and plasma oxidative stress markers, and plasma high-sensitivity C-reactive protein in hypercholesterolemic patients with and without type 2 diabetes mellitus: A 12-week, open-label, pilot study

Background: Oxidative stress and inflammation of the arterial wall are now recognized as important factors in the progression of atherosclerosis. C-reactive protein (CRP) has been defined as a sensitive but not specific marker of inflammation. Statin therapy has been reported to decrease plasma high-sensitivity CRP (hs-CRP) concentration in hypercholesterolemic patients. Objective: The aim of this study was to examine the effect of rosuvastatin on concentrations of plasma lipids, urine and plasma oxidative stress markers, and plasma hs-CRP in hypercholesterolemic patients with and without type 2 diabetes mellitus. Methods: Patients with hypercholesterolemia with and without type 2 diabetes mellitus were enrolled in this pilot study after written informed consent was given. At baseline and after 12 weeks of open-label treatment with rosuvastatin 2.5 mg/d, concentrations of plasma lipids, urine and plasma oxidative stress markers, and plasma hs-CRP were measured. Urine 8-iso-prostaglandin F 2α (8-iso-PGF 2α) and 8-hydroxy-2′-deoxyguanosine (8-OHdG) concentrations were also measured to asess whole-body oxidative stress. Plasma free-radical generation was estimated using a total reactive oxygen species (TROS) assay system. Adverse effects were assessed at each study visit (4-week intervals) through patient interviews and laboratory testing. Results: Thirty-five patients were enrolled with 1 dropping out prior to study completion; therefore, 34 patients (19 women, 15 men; mean [SE] age, 55.4 [13.6] years; range, 30–78 years) completed the study. Compared with baseline, significant decreases were found in serum concentrations of total cholesterol (TC) (252.3 [39.3] vs 187.8 [30.1] mg/dL; P < 0.001; Δ = 24.5%), LDL-C (162.0 [44.3] vs 98.5 [31.9] mg/dL; P < 0.001; Δ = 38.7%), and triglycerides (TG) (157.2 [93.6] vs 124.4 [69.9] mg/dL; P < 0.05; Δ = 11.7%) after 12 weeks of treatment with rosuvastatin. Serum HDL-C concentration did not change significantly from baseline (59.7 [20.5] vs 63.7 [19.3] mg/dL; Δ = 9.4%). The plasma LDL-C/HDL-C ratio decreased significantly after rosuvastatin treatment (3.03 [1.33] vs 1.72 [0.83]; P < 0.001; Δ = 43.2%). Compared with baseline, significant decreases were observed in urine concentrations of the oxidative stress markers after 12 weeks of rosuvastatin treatment: 8-iso-PGF 2α (342.8 [154.3] vs 300.6 [101.2] pg/mg; P < 0.05) and 8-OHdG (11.1 [4.53] vs 8.1 [2.7] ng/mg; P < 0.01). TROS decreased significantly (182.3 [29.0] vs 157.6 [17.3] U; P < 0.001), and plasma hs-CRP concentration also decreased significantly (0.107 [0.100] vs 0.054 [0.033] mg/dL; P < 0.05). When the patients' results were assessed according to the presence or absence of type 2 diabetes mellitus, urine 8-iso-PGF 2α concentration was significantly decreased from baseline only in the nondiabetic group. No adverse events were reported or observed during the course of the study. Conclusion: Rosuvastatin treatment was associated with significant reductions in plasma concentrations of TC, LDL-C, and TG, urine and plasma oxidative stress markers, and plasma hs-CRP in these hypercholesterolemic patients.

Effects Of Exercise And Diet On Nitric Oxide And Endothelin-1 Levels In Impaired Glucose Tolerance

Impaired glucose tolerance forms an intermediate stage in the natural history of diabetes mellitus. These individuals with impaired glucose tolerance (IGT) have a significant risk of developing diabetes and thus are an important target group for primary prevention. On the other hand, it is generally accepted that prolonged physical exercise increases insulin sensitivity and might be useful in the prevention of type 2 diabetes. PURPOSE: To determine the effects of chronic exercise and low-calorie diet on plasma NO and ET-1 levels in individuals with impaired glucose tolerance (IGT), and to elucidate the relationship between the oxidant stress markers and NO/ET-1 levels in the plasma before and following exercise episodes. METHODS: Individuals with IGT (n=14) participated in a regular exercise program starting at an intensity corresponding to 35% of the heart rate reserve of the individual and exercised for 40 minutes each day 3 days a week for 12 weeks. Physiological, anthropometric and biochemical measurements were done before, on the 6th week and at the end of the program. RESULTS: There was a significant reduction in BMI, body fat content, systolic and diastolic blood pressures as well as NO and ET-1 concentrations following 12 weeks of exercise and diet program. Exercise training significantly elevated subjects' maximum oxygen consumption whereas resting metabolic rates of the individuals did not change. Formation of TBARS in the plasma, which is an indicator of lipid peroxidation, was significantly reduced, while sulfhydryl (RSH) groups were significantly increased on the 6th weeks (p<0.05) and at the end of program (p<0.01). CONCLUSION: Our results demonstrate that exercise along with low-calorie diet, induced reductions in the plasma of both ET-1 and NO. Furthermore, upon completion of the program, beneficial effects were observed on anthropometrical measurements and plasma oxidant stress markers, indicating weight loss associated with exercise training and calorie restriction may effectively improve endothelial dysfunction in individuals with impaired glucose tolerance.

Protein and Antioxidants in an Isocaloric Carbohydrate Drink: Effect on Plasma Oxidative-Stress Markers and IL-6

The purpose of this study was to determine whether an isocaloric beverage with added protein and vitamins (CHOPA) would influence oxidative stress and inflammation after cycling to exhaustion as indicated by plasma protein carbonyls (PC), lipid hydroperoxides (LOOH), and interleukin-6 (IL-6). Twelve trained men (18-33 yr) volunteered and performed this randomized crossover study. Participants cycled at 70% VO2peak until fatigue and at 80% VO2peak 22-24 hr later to fatigue with either carbohydrate or CHOPA. Blood collected before the cycling at rest and 24, 48, and 72 hr after the exercise was analyzed for PC and LOOH spectrophotometrically and for IL-6 via an enzyme-linked immunosorbent assay. The data were analyzed with SPSS using repeated-measures ANOVA. PC demonstrated significant treatment (p = .037) and time (p = .004) effects with no Treatment x Time interaction. PC was higher in the CHOPA treatment than with CHO independent of time and increased at 24 (48%), 48 (59%), and 72 (67%) hr after exercise compared with preexercise values. Resting LOOH and IL-6 did not have any significant changes with time or treatment. These data indicate that an isocaloric CHOPA drink after 2 cycling bouts to exhaustion will exacerbate the resting PC level compared with an isocaloric drink, with no influence on plasma LOOH or IL-6. In addition, a modest significant increase in PC over time independent of treatment occurred, which suggests a mild oxidative stress in the days after exhaustive exercise.

Effects of estrogens on oxidative protein damage in plasma and tissues in ovariectomised rats

To assess estrogen-related changes in the redox status of the brain and liver proteins as well as the systemic oxidative stress in ovarectomised (OVX) rats Twelve-week-old, sexually mature female Sprague-Dawley rats (200-250g) were randomly divided into four groups: The following treatment combinations were administrated daily to all in 0.05 ml 96% ethanol solution by gastric gavage. (1) Sham operation (2) OVX rats (3) OVX rats [0.02 mg/kg/day of 17beta-estradiol (E2) and 0.01 mg/kg/day of norethisterone acetate] (4) OVX rats [E2 (0.01 mg/kg/day) and drospirenon (0.02 mg/kg/day)]. Estrogen levels were determined using routine clinical-chemistry methods. We also measured protein oxidation parameters such as protein carbonyl (PCO), total thiol (T-SH) and the other oxidative stress markers malondialdehyde (MDA) and glutathione (GSH). Ovariectomy resulted in abnormal elevation of plasma and tissue oxidative stress markers and changes in redox status of the proteins in tissue dependent manner. Supplementation of various estrogens combinations partially alleviated these abnormalities and restored redox homeostasis of proteins after the ovariectomy. Among the studied protein oxidation parameters, plasma and tissue PCO levels of the OVX rats were higher than those of the control groups (P < 0.01). Hormone replacement therapies (HRT) caused a decrease in PCO and MDA in both plasma and tissue of the OVX rats (P < 0.01). HRT in OVX rats decreased plasma MDA and increased liver and brain GSH (P < 0.01). Liver MDA levels of the Drospirenon-treated rats were lower than in the norethisterone acetate group (P < 0.01). On the other hand, Drospirenon increases brain GSH s more effectively than norethisterone acetate (P < 0.01). After bilateral oopherectomy, plasma and tissue T-SH levels decreased in the OVX group compared with control (P < 0.01). Norethisterone acetate increased plasma T-SH more effectively than Drospirenon (P < 0.05) The study showed the extent of oxidative protein damage (OPD) in this model of estrogen deficiency. The protective effect of estrogens against tissue specific OPD suggests that estrogens play an important role within the antioxidant defense systems in plasma, liver and brain. The exact molecular mechanisms leading to these findings are not yet completely known. Meanwhile, hormone replacement therapy for the prevention of OPD in a tissue specific manner may be required.

Association between the adiponectin promoter rs266729 gene variant and oxidative stress in patients with diabetes mellitus

Low levels of adiponectin are associated with type 2 diabetes and coronary heart disease (CHD). Recent evidence also suggests that low levels of adiponectin are associated with increased oxidative stress. Our aim was to examine the association between the rs266729 promoter gene variant (-11377C > G) and plasma markers of oxidative stress in diabetes subjects. Seven hundred and sixty-seven Caucasian subjects with diabetes were successfully genotyped (CC/CG/GG). Genotype data were analysed in relation to plasma total antioxidant status (TAOS) and Oxidized-LDL (Ox-LDL). Plasma adiponectin measurements were available in 206 samples. There was a significant association between genotype and plasma TAOS (CC: 42.1 +/- 13.4% vs. CG: 42.0 +/- 12.0% vs. GG: 47.9 +/- 12.0%, P = 0.02; for CC/CG vs. GG, P = 0.006). With respect to Ox-LDL, CC subjects had 8% higher plasma Ox-LDL compared with CG/GG [CC vs. CG vs. GG: 48.5 (36.3-60.2) U/L vs. 44.8 (35.6-54.1) U/L vs. 44.9 (41.2-49.1) U/L, for CC vs. CG/GG P = 0.03]. For plasma adiponectin, GG subjects had the highest levels [CC vs. CG vs. GG: 8.18 (5.69-15.38) microg/mL vs. 7.12 (5.34-12.97) microg/mL vs. 11.84 (6.98-25.25) microg/mL, P = 0.09; for CC/CG vs. GG, P = 0.05]. This study shows an association between a promoter variant in the adiponectin gene and plasma markers of oxidative stress. In line with previous studies, this work supports an antioxidant role for adiponectin which may explain its cardioprotective effect. Further prospective study is necessary to explore the effect of this gene variant in diabetes in relation to CHD risk and oxidative stress.

Effect of N‐acetylcysteine on the early expression of inflammatory markers in the retina and plasma of diabetic rats

The aim of this study is to investigate markers of inflammation and oxidative stress in an early model of diabetic retinopathy, correlate retinal and plasma results and evaluate the influence of treatment by N-acetylcysteine (NAC), a free radical scavenger. Four groups were studied: control (C), streptozotocin (STZ)-induced diabetic rats (D), STZ rats following 8 weeks of NAC (DT), and control rats following 8 weeks of NAC (CT). Plasma levels of free 15-F2t-isoprostane (15-F-2t-IsoP), superoxide dismutase (SOD) and tumour necrosis factor-alpha (TNF-alpha) were obtained. Primary antibodies against macrophages (ED-1), microglia (Ox-42), pericytes (NG-2), endothelial and perivascular cells (IB-4), haem oxygenase 1 (HO-1) and vascular endothelial growth factor (VEGF) were used. Expression of NG-2 was robust in C, CT, DT, and mild in D. The intensity of IB-4 was higher in D and DT compared with the C and CT. Ox-42 and ED-1 expression was higher in the D than in the DT, C or CT. Expression of VEGF and HO-1 was non-specific across the four groups. Plasma levels of 15-F-2t-IsoP and TNF-alpha were higher in the D as compared with the C, CT and DT. SOD levels were lower in the D when compared with the C, CT and D. Macrophage/microglia activation, pericyte loss and endothelial/perivascular cell changes occur early in the pathogenesis of DR. These changes are associated with an increase in plasma markers of oxidative stress and inflammation and are minimized by treatment with NAC. The results suggest that therapies that reduce free radicals will help minimize the early events in diabetic retinopathy in the STZ model.

Oxidative and Antioxidant Status in Plasma of Runners: Effect of Oral Supplementation with Natural Antioxidants

Aerobic exercise increases free radical production as a consequence of enhanced oxygen consumption. If free radical formation exceeds antioxidant capacity, lipids, proteins, and DNA may be oxidized. Oxidative stress is widely recognized as a factor in many degenerative human diseases. The role of dietary antioxidants in protection against disease is a topic of continuing interest. In fact, there is epidemiological evidence correlating a higher intake of nutrients possessing antioxidant abilities with a lower incidence of various human diseases. This study was directed at investigating whether changes in plasma antioxidant capacity and oxidative stress markers occur in voluntary wheel runners, before and after oral supplementation with lycopene and isoflavones. For this purpose, plasma antioxidant capacity and oxidative stress markers were assessed in long distance runners at the end of a 60-minute run. Comparisons were made between runners before and after 60 days of supplementation with lycopene and isoflavones. DNA damage in blood cells of the same samples was also evaluated by comet assay. This investigation shows that oral supplementation with lycopene and soy-derived isoflavones significantly reduced lipid peroxidation and enhanced plasma nonproteic antioxidant defense.

Are Zucker obese rats a useful model for cardiovascular complications in metabolic syndrome? Physical, biochemical and oxidative stress considerations

We wondered if Zucker obese (ZO) rats would be a good experimental model to evaluate cardiovascular complications of metabolic syndrome (MS). ZO rats were compared with both their littermate controls, Zucker lean (ZL) rats and to Wistar rats (reference strain). We designed this work:(i) to measure certain physical and biochemical characteristics of MS; (ii) to evaluate coronary and cardiac function in isolated conditions and after ischemia; and (iii) to study plasma and heart tissue oxidative stress markers. In vivo, ZO rats had higher levels of plasma glucose, cholesterol and triglycerides than their ZL littermates, but there was no difference between the groups for systolic arterial blood pressure and heart rate. In vitro, coronary endothelial function was notably impaired in ZO and ZL rats. After global ischemia, the worse ventricular recovery in ZO and ZL rats was associated with arrhythmias during reperfusion. We detected similar levels of plasma ascorbyle free radical, oxygen radical absorbance capacity and vitamin C concentrations in the three groups. Dihydroethidium staining showed higher superoxide production in the coronary vessels of ZO rats than in ZL and Wistar rats. Our results show that ZO might only correspond to early-stage cardiovascular complications associated with MS.

Association of oxidative stress and paraoxonase status with PROCAM risk score

Objectives Oxidative stress and paraoxonase activity play a significant role in the pathogenesis of cardiovascular disease (CVD). The Prospective Cardiovascular Münster (PROCAM) study evaluated the prevalence of CVD risk factors and postulated the prediction of future CVD events. We therefore investigated the association between plasma markers of oxidative stress and paraoxonase status with PROCAM risk score. Design and methods Oxidative stress status parameters [lipid peroxidation measured as thiobarbituric acid-reacting substances (TBARS), superoxide anion (O 2 −), superoxide dismutase (SOD) activity, total sulphydryl group content] and paraoxonase (PON1) status were assessed in 211 participants. The predicted 10-year risk was calculated according to the PROCAM algorithm. Results As expected subjects with high PROCAM risk score (high CVD risk) had significantly higher concentrations of oxidative stress parameters (TBARS and O 2 − P < 0.001 and P < 0.05, respectively). The PON1 192 phenotype distribution among CVD risk groups was not significantly different. Logistic regression analyses revealed significant associations of all the examined oxidative stress status parameters with calculated CVD risk score. The potential of the parameters for CVD risk prediction was tested via multivariate analysis. Only the O 2 − level retained a strong association with high CVD risk. Conclusions Our study demonstrated that high PROCAM risk score is associated with increased oxidative stress, indicating for the first time that elevated O 2 − is independently associated with high CVD risk.

Coenzyme Q10 distribution in blood is altered in patients with Fibromyalgia

Objective Coenzyme Q10 (CoQ 10) is an essential electron carrier in the mitochondrial respiratory chain and a strong antioxidant. Signs and symptoms associated with muscular alteration and mitochondrial dysfunction, including oxidative stress, have been observed in patients with fibromyalgia (FM). The aim was to study CoQ 10 levels in plasma and mononuclear cells, and oxidative stress in FM patients. Methods We studied CoQ 10 level by HPLC in plasma and peripheral mononuclear cells obtained from patients with FM and healthy control subjects. Oxidative stress markers were analyzed in both plasma and mononuclear cells from FM patients. Results Higher level of oxidative stress markers in plasma was observed respect to control subjects. CoQ 10 level in plasma samples from FM patients was doubled compared to healthy controls and in blood mononuclear cells isolated from 37 FM patients was found to be about 40% lower. Higher levels of ROS production was observed in mononuclear cells from FM patients compared to control, and a significant decrease was induced by the presence of CoQ 10. Conclusion The distribution of CoQ 10 in blood components was altered in FM patients. Also, our results confirm the oxidative stress background of this disease probably due to a defect on the distribution and metabolism of CoQ 10 in cells and tissues. The protection caused in mononuclear cells by CoQ 10 would indicate the benefit of its supplementation in FM patients.