Muaz Belviranli

The Effect of Grape Seed Extracts on Serum Paraoxonase Activities in Streptozotocin-Induced Diabetic Rats

Procyanidins, a group of flavonoids, are oligomeric forms of catechins that are abundant in red wine, grapes, cocoa, and apples. Paraoxonase acts as an antioxidant enzyme and protects low-density lipoprotein-cholesterol against oxidation. In our study we aimed to evaluate the effects of grape seed extract (GSE) on paraoxonase activities in streptozotocin-induced diabetic rats. Our study included four groups of rats: Group I (n = 8), control; Group II (n = 10), GSE-supplemented; Group III (n = 6), streptozotocin-induced diabetic; and Group IV (n = 7), GSE-supplemented diabetic rats. Serum paraoxonase activities were determined with a spectrophotometric method. Paraoxonase activities in Group III were significantly lower than in the other three groups (P < .001, P < .001, and P = .005 for Groups I, II, and IV, respectively), and Group IV showed increased paraoxonase activities compared to Group III (P = .005). This is the first study to show an association between paraoxonase status and GSE supplementation and demonstrated that GSE increased paraoxonase activities. This beneficial effect of GSE was more obvious in the diabetic group, which was more prone to atherosclerotic events compared to the healthy population.

Effects of grape seed extract supplementation on exercise-induced oxidative stress in rats.

The aim of the present study was to investigate the effects of grape seed extract (GSE) supplementation on exercise performance and oxidative stress in acutely and chronically exercised rats. A total of sixty-four male rats were used in the study. Rats were divided into six groups: control, chronic exercise control, acute exercise control (AEC), GSE-supplemented control, GSE-supplemented chronic exercise and GSE-supplemented acute exercise groups. Chronic exercise consisted of treadmill running at 25 m/min, 45 min/d, 5 d a week for 6 weeks. Rats in the acute exercise groups were run on the treadmill at 30 m/min until exhaustion. GSE were given at 100 mg/kg of body weight with drinking water for 6 weeks. Plasma was separated from blood samples for the analysis of oxidative stress markers. There was no significant difference in time of exhaustion between the acute exercise groups. Plasma malondialdehyde (MDA) levels were higher in the acute exercise groups and lower in the chronic exercise groups. GSE supplementation decreased MDA levels. Xanthine oxidase and adenosine deaminase activities were higher in the AEC group compared to all the other groups. NO levels were increased with both chronic exercise and GSE supplementation. Superoxide dismutase and glutathione peroxidase activities were lower in the acute exercised groups and higher in the chronic exercised groups. GSE supplementation caused an increase in antioxidant enzyme activities. In conclusion, GSE supplementation prevents exercise-induced oxidative stress by preventing lipid peroxidation and increasing antioxidant enzyme activities.

The Effect of Supplementation of Grape Seed Proanthocyanidin Extract on Vascular Dysfunction in Experimental Diabetes

Increased oxidative stress and impaired endothelium-dependent relaxation could underlie many of the vascular complications associated with diabetes. We aimed to investigate the effect of supplementation with grape seed proanthocyanidin extract (GSPE), a natural antioxidant, on vascular responses and oxidative stress in streptozotocin-induced diabetic rats. Male Sprague-Dawley rats were divided into three groups: control rats, untreated diabetic rats, and GSPE (100 mg/kg, for 6 weeks)-supplemented diabetic rats. Thoracic aorta rings of the rats were mounted in organ baths, and relaxant responses to acetylcholine (ACh), A23187, and sodium nitroprusside (SNP) were assayed in tissues precontracted with 60 mM KCl. Plasma samples used for the measurement of malondialdehyde (MDA) level and superoxide dismutase (SOD) activity. The endothelium-dependent relaxations in response to ACh and A23187 were impaired, but endothelium-independent relaxation in response to SNP did not change in diabetic rats. Supplementation with GSPE significantly improved the relaxant responses to ACh and A23187. The MDA level was significantly elevated and the plasma SOD activity was decreased in diabetic rats, but supplementation with GSPE attenuated the elevated MDA levels and increased plasma SOD activity. Thus supplementation of GSPE may attenuate oxidative stress through the inhibition of lipid peroxidation and may restore endothelial function and reduce the risk of vascular disease in diabetes.

Effects of Coenzyme Q10 Supplementation on Plasma Adiponectin, Interleukin-6, and Tumor Necrosis Factor-α Levels in Men

The aim of the study was to determine the effects of coenzyme Q10 supplementation on plasma adiponectin, interleukin (IL)-6, and tumor necrosis factor (TNF )-alpha levels in sedentary men. Fourteen healthy, nonsmoking, sedentary men participated in the study. The protocol was approved by the Ethical Committee of our institution. This study was a randomized, double-blind, crossover trial. Blood samples were collected from all participants before coenzyme Q10 or placebo supplementation. The participants were randomly allocated to two groups. Seven participants received oral coenzyme Q10 (100 mg/day) supplementation, and seven participants received placebo (glucose) for 8 weeks. At the end of the 8 weeks, a second blood sampling was performed. After a 4-week washout period, placebo was given to the participants who used coenzyme Q10 the first time, and vice versa, and blood sampling was repeated. Plasma was stored at -80 degrees C until the time of analysis for adiponectin, IL-6, and TNF-alpha. Both CoQ10 and placebo supplementation did not affect plasma adiponectin and TNF-alpha levels. IL-6 level increased with coenzyme Q10 supplementation, but this increase did not differ from that seen with placebo supplementation. Coenzyme Q10 supplementation did not affect plasma adiponectin, IL-6, and TNF-alpha levels in sedentary men.

Effects of grape seed polyphenols on oxidative damage in liver tissue of acutely and chronically exercised rats.

The objective of the present study was to investigate the effects of grape seed extract (GSE) supplementation on oxidative stress and antioxidant defense markers in liver tissue of acutely and chronically exercised rats. Rats were randomly assigned to six groups: Control (C), Control Chronic Exercise (CE), Control Acute Exercise (AE), GSE‐supplemented Control (GC), GSE‐supplemented Chronic Exercise(GCE) and GSE‐supplemented Acute Exercise (GAE). Rats in the chronic exercise groups were subjected to a six‐week treadmill running and in the acute exercise groups performed an exhaustive running. Rats in the GSE supplemented groups received GSE (100 mg.kg−1.day−1) in drinking water for 6 weeks. Liver tissues of the rats were taken for the analysis of malondialdehyde (MDA), nitric oxide (NO) levels and total antioxidant activity (AOA) and xanthine oxidase (XO) activities. MDA levels decreased with GSE supplementation in control groups but increased in acute and chronic exercise groups compared to their non‐supplemented control. NO levels increased with GSE supplementation. XO activities were higher in AE group compared to the CE group. AOA decreased with GSE supplementation. In conclusion, while acute exercise triggers oxidative stress, chronic exercise has protective role against oxidative stress. GSE has a limited antioxidant effect on exercise‐induced oxidative stress in liver tissue. Copyright

The relationship between brain-derived neurotrophic factor, irisin and cognitive skills of endurance athletes

ABSTRACT Objective: The objective of this study was to assess the cognitive performance of endurance athletes and its relation with circulating brain-derived neurotrophic factor (BDNF) and irisin levels. Methods: 26 endurance athletes (14 elite orienteers (mean ± SD: age = 26.33 ± 4.08, body weight = 70.33 ± 4.64, body height = 177.7 ± 6.1), 12 pentathletes (mean ± SD: age = 29.42 ± 5.32, body weight = 74.77 ± 6.59, body height = 180.8 ± 3.8)) and ten sedentary (mean ± SD: age = 27.30 ± 2.06, body weight = 76.65 ± 12.50, body height = 176.9 ± 5.2) men at almost same ages and educational levels participated in this study. Cognitive functions were analyzed with mini-mental-state examination (MMSE) and Isaacs’ Set Test of Verbal Fluency (IST) tests. Insulin-like growth factor-1 (IGF-1), BDNF and irisin levels were measured in the blood samples. Results: The MSSE and IST scores of the endurance athletes were higher than that of the sedentary control group (P < 0.05). Serum IGF-1 levels were higher in the pentathletes (111.18 ± 22.26 ng mL−1) than the orienteers (85.89 ± 19.32 ng mL−1) (P < 0.05). Plasma BDNF (2.78 ± 0.81, 4.28 ± 1.03, and 3.93 ± 0.77 ng mL−1 in the sedentary, orienteers and pentathletes, respectively) and irisin (3.25 ± 0.70, 6.16 ± 0.99, and 6.58 ± 1.09 µg mL−1 in the sedentary, orienteers and pentathletes, respectively) concentrations of the endurance trained athletes were higher than that of the sedentary control group (P < 0.05). Positive correlation between the cognitive function test results and BDNF and irisin concentrations were observed (P < 0.05). There was also a positive correlation between the circulating irisin and BDNF concentrations (P < 0.05). Conclusion: These results suggested that irisin and BDNF levels positively correlated with cognition in the endurance trained athletes.

Age and sex affect spatial and emotional behaviors in rats: the role of repeated elevated plus maze test.

The main objective of the study was to investigate the effects of age and sex differences on locomotor activity, learning and memory in rats. Another objective was to investigate whether repeated elevated plus maze tests induce anxiety in rats. Eighty Wistar rats were divided into eight groups according to their sex, age and anxiety status. Locomotor activity was assessed in open field. Repeated anxiety tests were performed in elevated plus maze. Spatial learning and memory were evaluated with the Morris water maze. All behavioral tests were recorded online and analyzed offline with an analytical software. Exploratory behavior was lower in anxiety-induced rats. Male rats had lower anxiety levels, locomotor activity and exploratory behavior compared to females. During the training period of Morris water maze latency to find platform, total distance traveled and average swimming speed decreased in all groups with repeated tests and young rats generally were faster than aged rats. During the probe trial, although the number of platform crossings was not affected, time spent in the platform zone was higher in the young groups compared to the aged groups. In conclusion, age and sex affect locomotor activity, learning and memory in different aspects.

Protective effects of curcumin supplementation on intestinal ischemia reperfusion injury.

The aim of this study was to investigate the effects curcumin on inflammation and oxidative stress markers in the intestinal ischemia reperfusion (IIR) injury induced rats. Rats were divided into four groups: sham (S), intestinal IR (IIR), curcumin plus sham (CS), and curcumin plus intestinal IR (CIIR). Curcumin was given 200 mg kg⁻¹ for 20 days. IIR was produced by 45 min of intestinal ischemia followed by a 120 min of reperfusion. Although interleukin-6 levels tended to increase in IIR group tumor necrosis factor-α levels were not different. Intestinal myeloperoxidase activity in CS group was lower than IIR group. In intestine and heart tissues, malondialdehyde levels in CS and CIIR groups were lower than S and IIR groups. Superoxide dismutase activity in CIIR group was higher than IIR group in intestine and lung tissues. Curcumin has a protective role against ischemia reperfusion injury.

Oxidative stress and anti-oxidant status in diabetic rat liver: Effect of plant polyphenols

Increased evidence in role of oxidative stress and grape seed extract (GSE) in diabetes and its complication led us to investigate the changes of oxidative stress and anti-oxidant defence in liver tissue of diabetic rats and possible effects of GSE. Diabetes was induced by a single intraperitoneal injection of streptozotocin. Seven days after STZ injection four groups were formed: Control, GSE-supplemented control, diabetic and GSE-supplemented diabetic and GSE was given for 6 weeks. Malondialdehyde levels and xanthine oxidase activities were not different among the groups. However, nitric oxide (NO) levels were higher in diabetic and GSE supplemented groups compared with non-diabetic and non-supplemented groups, respectively. Total anti-oxidant activity (TAA) was lower in diabetic groups compared with their non-diabetic controls and it was not affected by GSE. In conclusion, GSE supplementation has limited protective effect in liver tissue of diabetic rats via affecting NO levels and was not affecting TAA.

Coenzyme Q10 and its Relation with Oxidant and Antioxidant System Markers in Patients with End-Stage Renal Disease

Abstract Rationale and objectives: Oxidative stress is increased in chronic kidney disease (CKD) patients and end-stage renal disease (ESRD) patients undergoing dialysis treatment. Coenzyme Q10 (CoQ10) is a ubiquitous and strong antioxidant. Role of CoQ10 is not fully evaluated in renal patients. We aimed to investigate the relationship of CoQ10 with oxidant and antioxidant system markers in patients with renal disease. Material and methods: Forty patients with CKD (stages 3–5) who were managed conservatively without dialysis treatment, 40 hemodialysis, and 60 chronic ambulatory peritoneal dialysis (CAPD) patients were included in the study. Biochemical and whole blood analyses were done using hospital auto-analyzers from stored samples. Serum CoQ10, malondialdehyde (MDA), superoxide dismutase (SOD), and antioxidant activity (AOA) levels were determined. Main findings: There was no difference among the groups in terms of serum CoQ10 levels. However, other components of antioxidant system, namely, SOD and AOA were significantly higher in CAPD patients when compared to CKD patients. MDA levels were not significantly different among the groups. Principal conclusion(s): The results of this study showed no difference among CKD, CAPD, and hemodialysis patients in terms of serum CoQ10 levels.