scholarly journals Metabolic Memory Phenomenon and Accumulation of Peroxynitrite in Retinal Capillaries

2007 ◽  
Vol 2007 ◽  
pp. 1-7 ◽  
Author(s):  
Renu A. Kowluru ◽  
Mamta Kanwar ◽  
Alexander Kennedy
Keyword(s):  
Diabetic Retinopathy ◽  
Glycemic Control ◽  
Antioxidant Capacity ◽  
Total Antioxidant Capacity ◽  
Metabolic Memory ◽  
Retinal Microvasculature ◽  
Total Antioxidant ◽  
Acellular Capillaries ◽  
Mnsod Activity ◽  
Retinal Capillaries

Aim. Diabetic retinopathy resists reversal after good glycemic control (GC) is reinitiated, and preexisting damage at the time of intervention is considered as the major factor in determining the outcome of the GC. This study is to investigate the role of peroxynitrite accumulation in the retinal capillaries in the failure of retinopathy to reverse after reestablishment of GC, and to determine the effect of this reversal on the activity of the enzyme responsible for scavenging mitochondrial superoxide, MnSOD.Methods. In streptozotocin-diabetic rats, 6 months of poor glycemic control (PC, glycated hemoglobin,GHb>12.0%) was followed by 6 additional months of GC (GHb about 6%). The trypsin-digested retinal microvessels were prepared for immunostaining of nitrotyrosine (a measure of peroxynitrite) and for counting the number of acellular capillaries (a measure of histopathology). The retina from the other eye was used to quantify nitrotyrosine concentration, MnSOD activity and the total antioxidant capacity.Results. Reversal of hyperglycemia after 6 months of PC had no significant effect on nitrotyrosine concentration in the retina, on the nitrotyrosine-positive retinal capillary cells and on the number of acellular capillaries; the values were similar in PC-GC and PC groups. In the same rats retinal MnSOD activity remained inhibited and the total antioxidant capacity was subnormal 6 months after cessation of PC.Conclusions. Peroxynitrite accumulation in the retinal microvasculature, the site of histopathology, fails to normalize after reversal of hyperglycemia, and superoxide remains inadequately scavenged. This failure of reversal of peroxynitrite accumulation could be, in part, responsible for the resistance of diabetic retinopathy to reverse after termination of PC.

scholarly journals The Association between Diabetic Retinopathy and Levels of Ischemia-Modified Albumin, Total Thiol, Total Antioxidant Capacity, and Total Oxidative Stress in Serum and Aqueous Humor

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Kadir Kirboga ◽  
Ayse V. Ozec ◽  
Mustafa Kosker ◽  
Ayhan Dursun ◽  
Mustafa I. Toker ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Diabetic Retinopathy ◽  
Antioxidant Capacity ◽  
Aqueous Humor ◽  
Total Antioxidant Capacity ◽  
Control Group ◽  
Total Thiol ◽  
Median Serum ◽  
Total Antioxidant ◽  
Total Oxidative Stress

Purpose. To investigate the oxidant and antioxidant status of patients with type 2 diabetes mellitus and nonproliferative diabetic retinopathy (DRP).Methods. Forty-four patients who had cataract surgery were enrolled in the study. We included 22 patients with DRP in one group and 22 patients in the control group. Samples of aqueous humor and serum were taken from all patients. Serum and aqueous ischemia-modified albumin (IMA), total thiol, total antioxidant capacity (TAC), and total oxidative stress (TOS) levels were compared in two groups.Results. Median serum IMA levels were 44.80 absorbance units in the DRP group and 40.15 absorbance units in the control group (P=0.031). Median serum total thiol levels in the DRP group were significantly less than those in the control group (3051.13 and 3910.12, resp.,P=0.004). Mean TOS levels in the serum were 2.93 ± 0.19 in the DRP group and 2.61 ± 0.26 in the control group (P=0.039). The differences in mean total thiol, TAC, and TOS levels in the aqueous humor and mean TAC levels in the serum were not statistically significant.Conclusion. IMA, total thiol, and TOS levels in the serum might be useful markers in monitoring the risk of DRP development.

Trans-resveratrol supplement lowers lipid peroxidation responses of exercise in male Wistar rats

2020 ◽  
pp. 1-6 ◽  
Author(s):  
Masoud Nasiri ◽  
Saja Ahmadizad ◽  
Mehdi Hedayati ◽  
Tayebe Zarekar ◽  
Mehdi Seydyousefi ◽  
...  
Keyword(s):  
Lipid Peroxidation ◽  
Antioxidant Capacity ◽  
Total Antioxidant Capacity ◽  
Wistar Rats ◽  
Enzymatic Antioxidants ◽  
Acute Response ◽  
Total Antioxidant ◽  
Male Wistar Rats ◽  
Exercise Induced ◽  
And Control

Abstract. Physical exercise increases free radicals production; antioxidant supplementation may improve the muscle fiber’s ability to scavenge ROS and protect muscles against exercise-induced oxidative damage. This study was designed to examine the effects of all-trans resveratrol supplementation as an antioxidant to mediate anti-oxidation and lipid per-oxidation responses to exercise in male Wistar rats. Sixty-four male Wistar rats were randomly divided into four equal number (n = 16) including training + supplement (TS), training (T), supplement (S) and control (C) group. The rats in TS and S groups received a dose of 10 mg/kg resveratrol per day via gavage. The training groups ran on a rodent treadmill 5 times per week at the speed of 10 m/min for 10 min; the speed gradually increased to 30 m/min for 60 minutes at the end of 12th week. The acute phase of exercise protocol included a speed of 25 m/min set to an inclination of 10° to the exhaustion point. Superoxide dismutase (SOD), glutathione peroxidase (GPx), catalase (CAT) activity, non-enzymatic antioxidants bilirubin, uric acid, lipid peroxidation levels (MDA) and the total antioxidant capacity (TAC) were measured after the exercise termination. The data were analyzed by using one-way ANOVA. The result showed that endurance training caused a significant increase in MDA level [4.5 ± 0.75 (C group) vs. 5.9 ± 0.41 nmol/l (T group)] whereas it decreased the total antioxidant capacity [8.5 ± 1.35 (C group) vs. 7.1 ± 0.55 mmol/l (T group)] (p = 0.001). In addition, GPx and CAT decreased but not significantly (p > 0.05). The training and t-resveratrol supplementation had no significant effect on the acute response of all variables except MDA [4.3 ± 1.4 (C group) vs. 4.0 ± 0.90 nmol/l (TS group)] (p = 0.001) and TAC [8.5 ± 0.90 (C group) vs. 6.6 ± 0.80 mmol/l (TS group)] (p = 0.004). It was concluded that resveratrol supplementation may prevent exercise-induced oxidative stress by preventing lipid peroxidation.

Summer Day/Night Gender Differences in Serum Total Antioxidant Capacity as a Methodological Pitfall in Human Antioxidant Research

2016 ◽  
Vol 4 (2) ◽  
Author(s):  
Armando L. Morera-Fumero ◽  
Pedro Abreu-Gonzalez ◽  
Lourdes Fernandez- Lopez ◽  
Estefanía Díaz-Mesa ◽  
Maria del Rosario Cejas-Mendez
Keyword(s):  
Gender Differences ◽  
Antioxidant Capacity ◽  
Total Antioxidant Capacity ◽  
Total Antioxidant

EXTRACTION OPTIMIZATION AND ANTIOXIDANT ACTIVITY OF PHENOLIC COMPOUNDS FROM AVOCADO PEEL

2019 ◽  
pp. 49-59
Author(s):  
Nu Linh Giang Ton ◽  
Thi Hoai Nguyen ◽  
Quoc Hung Vo
Keyword(s):  
Antioxidant Activity ◽  
Response Surface Methodology ◽  
Antioxidant Capacity ◽  
Response Surface ◽  
Total Antioxidant Capacity ◽  
Total Phenolic Content ◽  
Phenolic Content ◽  
Quadratic Model ◽  
Total Phenolic ◽  
Total Antioxidant

Avocado peel has been considered as a potential source of natural antioxidants in which phenolics are among the most important compounds. Therefore, this study aims to optimize the extraction process of phenolics using response surface methodology and evaluate the corresponding antioxidant activity. From the quadratic model, the optimal condition was determined including the ethanol concentration 54.55% (v/v), the solvent/solute ratio 71.82/1 (mL/g), temperature 53.03 oC and extraction time 99.09 min. The total phenolic content and the total antioxidant capacity at this condition with minor modifications were 26,74 ± 0,04 (mg GAE/g DW) and 188.06 ± 1.41 (mg AAE/g DW), respectively. The significant correlation between total phenolic content and total antioxidant capacity was also confirmed. Key words: response surface methodology, central composite rotatable design, total phenolic content, total antioxidant capacity, avocado peel

Evaluation of Salivary Antioxidants and Oxidative Stress Markers in Male Smokers

2019 ◽  
Vol 22 (7) ◽  
pp. 496-501
Author(s):  
Fatemeh Ahmadi-Motamayel ◽  
Parisa Falsafi ◽  
Hamidreza Abolsamadi ◽  
Mohammad T. Goodarzi ◽  
Jalal Poorolajal
Keyword(s):  
Oxidative Stress ◽  
Uric Acid ◽  
Free Radicals ◽  
Antioxidant Capacity ◽  
Cigarette Smoke ◽  
Total Antioxidant Capacity ◽  
The Body ◽  
Total Antioxidant ◽  
The Mean ◽  
And Oxidative Stress

Background: Cigarette smoke free radicals can cause cellular damage and different diseases. All the body fluids have antioxidants which protect against free radicals. Objective: The aim of this study was to evaluate salivary total antioxidant capacity and peroxidase, uric acid and malondialdehyde levels in smokers and a nonsmoking control group. Methods: Unstimulated saliva was collected from 510 males. A total of 259 subjects were current smokers and 251 were non-smokers. The levels of salivary total antioxidant capacity, uric acid, peroxidase and malondialdehyde were measured using standard procedures. Data were analyzed with t test and ANOVA. Results: The smokers were younger and dental hygiene index was higher than healthy nonsmoking controls. The mean total antioxidant capacity in smokers and nonsmokers was 0.13±0.07 and 0.21±011, respectively (P=0.001). Smokers had significantly lower peroxidase and uric acid levels than healthy controls. In addition, the mean malondialdehyde levels in the smokers and nonsmokers were 4.55 ±2.61 and 2.79 ±2.21, respectively (P=0.001). Conclusion: Cigarette smoke produces free radical and oxidative stress, causing many side effects. Salivary antioxidant levels decreased and malondialdehyde levels increased in smokers, indicating the high oxidative stress among smokers compared to nonsmokers. Cigarette smoke had deleterious effects on main salivary antioxidants levels.

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