Protective factors against oxygen free radicals and hydrogen peroxide in rheumatoid arthritis synovial fluid

Oxygen free radicals are probably involved in the pathogenesis of rheumatoid arthritis (RA). The enzymes involved in protection against oxygen free radicals and H2O2 (superoxide dismutase, catalase, and glutathione peroxidase) were measured. Superoxide dismutase was not increased, glutathione peroxidase was slightly and catalase was strongly elevated in RA synovial fluid (SF) compared with control SF. Although these enzymes are present in SF, the activities are insufficient to protect against oxygen free radicals and H2O2. In contrast to transferrin, ferritin was increased in RA synovial fluid. Ceruloplasmin was also elevated. When rat liver microsomes were used as a target for oxygen free radicals, serum and SF were both protective. Gel filtration experiments showed that the fraction pattern in which there was maximal protective potential against lipid peroxidation corresponded closely to the level of ceruloplasmin. After removal of ceruloplasmin from serum or SF, about 70% of the protective capacity disappeared. It is concluded that ceruloplasmin is an important protector against oxygen free radicals.     

Role of active oxygen, lipid peroxidation, and antioxidants in the pathogenesis of gastric mucosal injury induced by indomethacin in rats.

The roles of active oxygen, lipid peroxidation, and the antioxidative defence mechanism in gastric mucosal injury induced by treatment with indomethacin in rats were investigated. The total area of gastric erosions and concentration of lipid peroxides in the gastric mucosa increased with time after administration of indomethacin (20 mg/kg, orally). The alpha-tocopherol:total cholesterol ratio in serum was significantly decreased and the activity of glutathione peroxidase, an important enzyme to scavenger of lipid peroxides, was inhibited by the administration of indomethacin. Treatments with superoxide dismutase and catalase inhibited the increases in gastric mucosal erosions and lipid peroxides in the gastric mucosa, and the reduction of serum alpha-tocopherol. Treatment with these scavengers did not improve the decreased glutathione peroxidase activity. These findings suggest that active oxygen species and lipid peroxidation play an important part in the pathogenesis of gastric mucosal injury induced by indomethacin, and that the decreased glutathione peroxidase activity aggravated the injury due to accelerated accumulation of hydrogen peroxide and lipid peroxides in the gastric mucosal cell.     

Correlation of serum paraoxonase activities in known cases of 130 elderly hypertensive South Asian aged 56–64 years – a hospital based study

ObjectiveTo evaluate paraoxonase activity, antioxidant status and lipid peroxidation in hypertensive participants and to address the hypothesis that oxidative modifications of lipids due to hypertension can cause changes in serum paraoxonase activities.MethodsThe serum paraoxonase activities, antioxidants and lipid peroxidation were determined in 130 hypertensive participants and 130 age-sexes matched normotensive healthy volunteers served as control. Serum paraoxonase activities were measured by enzymatic kit. The glutathione peroxidase, superoxide dismutase and catalase activity were determined by standard methods. Malondialdehyde was measured by thiobarbituric acid reaction. Conjugated diene level was measured by Recknagel and Glende method. Serum uric acid, total bilirubin, serum albumin, serum ascorbic acid and lipid profile were analyzed by standard methods.ResultsTotal cholesterol, triglycerides, low-density lipoprotein cholesterol were significantly higher and high-density lipoprotein cholesterol were significantly lower in hypertensive patients when compared to normotensive healthy controls. The superoxide dismutase, glutathione peroxidase and catalase were significantly lower in hypertensive when compared with normotensive. Similar findings were observed in the levels of albumin, uric acid, bilirubin and ascorbic acid when hypertensives were compared with normotensive. The oxidative stress indicators namely malondialdehyde and conjugated diene were significantly higher and paraoxonase activity were significantly lower in hypertensive.ConclusionsOur study concludes that paraoxonase activities are bound to alter in hypertension which is caused due to interplay of several confounding factors namely oxidative stress, increased oxidized low-density lipoprotein and depletion of antioxidants.     

CuZn superoxide dismutase, Mn superoxide dismutase, catalase and glutathione peroxidase in lymphocytes and erythrocytes in insulin-dependent diabetic children

CuZn superoxide dismutase, Mn superoxide dismutase, catalase and glutathione peroxidase activities in lymphocytes and erythrocytes were studied in 9 children with insulin-dependent diabetes mellitus (IDDM) as well as in 21 healthy children. The mean erythrocyte CuZn superoxide dismutase and glutathione peroxidase were statistically significantly lower in the IDDM group compared with the controls although almost all IDDM results fell within the mean +/- 2 SD limits of the controls. The small differences found can hardly be assigned biological significance. Erythrocyte catalase as well as lymphocyte CuZn superoxide dismutase and Mn superoxide dismutase did not differ from the controls.     

Activity of Superoxide Dismutase, Catalase, Glutathione Peroxidase, and Glutathione Reductase in Different Stages of Colorectal Carcinoma

Background

Reactive oxygen species are involved in the pathogenesis of colorectal carcinoma. Clarification of oxidative/antioxidant specificities of different stages of colorectal carcinoma is of special importance.

Aim

To determine oxidative/antioxidant status in plasma of patients with different stages of colorectal carcinoma using malondialdehyde concentration, superoxide dismutase, catalase, glutathione peroxidase, and glutathione reductase activities and distribution of superoxide dismutase isoforms.

Methods

Lipid peroxidation and antioxidant enzymes activity were estimated using spectrophotometric methods. Reverse zymography was applied for characterization of superoxide dismutase isoforms.

Results

Lipid peroxidation is increased in all groups compared to the control, but without differences between different stages of colorectal carcinoma. Total superoxide dismutase activity is lower in all colorectal carcinoma groups than in control, and there is a significant increase in tumor stage IV when compared with tumor stage II. Manganese superoxide dismutase isoform is dominant in all groups and its relative activities are significantly higher than activities of a copper/zinc isoform. Total peroxidase potential reflected in catalase and glutathione peroxidase activity is increased when compared to the control, but without any significant differences between colorectal carcinoma groups. Glutathione reductase activity is lower in all colorectal carcinoma groups than in control, and a significant decrease in glutathione reductase activity was obtained between patients in tumor stage II and III compared to tumor stage IV.

Conclusions

Colorectal carcinoma is characterized by increased oxidative stress and antioxidant disbalance. Progression of disease is followed by an increase in redox disbalance.     

Malondialdehyde, lipofuscin and activity of antioxidant enzymes during physical exercise in patients with essential hypertension.

DESIGN: To clarify the role of oxidative damage in essential hypertension, levels of lipid peroxidation products (malondialdehyde and lipofuscin) and activity of antioxidant enzymes (superoxide dismutase and glutathione peroxidase) were examined during a short period of physical exercise. PATIENTS AND METHODS: We studied 11 male patients with mild to moderate essential hypertension in World Health Organization classes I or II and 10 healthy male controls. Physical exercise was performed on a bicycle ergometer at graded intensities of 1.0, 1.5 and 2.0 W/kg body weight Plasma concentrations of lipofuscin, malondialdehyde, epinephrine, norepinephrine, insulin, free fatty acids and glucose were determined. Superoxide dismutase activity was analysed in erythrocytes and glutathione peroxidase activity in whole blood. RESULTS: Concentrations of lipofuscin and malondialdehyde were significantly elevated in hypertensive patients. Superoxide dismutase activity was not different between groups, while glutathione peroxidase activity was significantly decreased in hypertensive subjects. During exercise, the concentration of malondialdehyde and antioxidant enzyme activities increased significantly in both groups. No differences were found in absolute increases between the normotensive and hypertensive subjects. The levels of glucose, insulin and free fatty acids were similar in both groups. Basal concentrations of catecholamines and also the exercise-induced increases were lower in hypertensive patients. CONCLUSIONS: Our results indicate increased oxidative damage in patients with essential hypertension, which might be caused by a decrease in the activity of glutathione peroxidase. The ability of superoxide dismutase and glutathione peroxidase to respond to increased production of reactive oxygen species during a short period of physical exercise was not impaired in hypertensive subjects.     

Superoxide Dismutase, Glutathione Peroxidase, Catalase and Lipid Peroxidation of Normal and Sickled Erythrocytes

Sickled erythrocytes showed reduced glutathione peroxidase and catalase activities in comparison to normal erythrocytes. In addition, increased levels of superoxide dismutase and 'peroxidation potential'as well as fluorescent lipid pigments and malonaldehyde suggestive of membrane lipid peroxidation were found in sickled erythrocytes. Finally, sickled erythrocytes showed membrane 'bound'Heinz bodies as well as reduced membrane lipids and unsaturated fatty acids. From these observations, it is suggested that membrane lipid peroxidation occurs in sickled cells.     

Effects of iron loading on free radical scavenging enzymes and lipid peroxidation in rat liver

A comparison of the antioxidant protective system and presence of lipid peroxidation was made between rats iron-loaded by two different mechanisms. Superoxide dismutase activity, glutathione peroxidase activity, and reduced glutathione concentrations, together with malondialdehyde production, were measured in the livers of rats chronically iron-overloaded by (a) parenteral iron (primarily Kupffer cell iron deposition) and (b) dietary carbonyl iron (mainly parenchymal iron deposition). In carbonyl iron-treated rats, hepatic superoxide dismutase activity was significantly decreased, whereas hepatocyte lipid peroxidation, as measured by malondialdehyde levels, was significantly increased when compared with control rats at or above iron concentrations of 100 and 185 mumol/g dry wt, respectively. However, no significant decrease in superoxide dismutase activity or significant increase in malondialdehyde levels was observed in iron dextran-treated rats. Glutathione peroxidase activities and reduced glutathione concentrations in rats, iron-loaded by either method, were not significantly different from those of control animals. These results suggest that the deposition of iron in the reticuloendothelial cells of the liver does not lead to lipid peroxidation; however, iron deposited in the parenchymal cells of the liver may lead to an altered free radical antioxidant protective system, resulting in lipid peroxidation in these cells at a similar level of iron loading. We conclude that the cellular site of iron deposition as well as the hepatic iron concentration is important in determining iron-induced liver injury.     

Acute phase response and oxidative stress status in familial Mediterranean fever (FMF)

We aimed to determine acute phase response (APR) and oxidative stress in patients with familial Mediterranean fever (FMF) and compare these characteristics with those in healthy controls; 20 patients with FMF and 15 healthy controls were enrolled in the study. The erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP), fibrinogen, and leukocyte levels were determined as markers of APR. Thiobarbituric acid reactive substances (TBARS), conjugated diene, and lipid hydroperoxide levels were measured as markers of lipid peroxidation. Carbonyl group and thiol (T-SH) levels were analyzed to determine the oxidative damage to proteins, and 8-hydroxy-2-deoxyguanosine (8-OHdG) was measured to reflect DNA oxidation. The erythrocyte glutathione (GSH) level, and glutathione peroxidase (GSH-Px), CuZn superoxide dismutase (CuZn SOD), and catalase activities were measured as markers of antioxidant status. Conjugated diene (p < 0.001) and carbonyl group (p < 0.05) levels were significantly higher and GSH-Px activity (p < 0.01) was significantly lower in FMF patients compared with controls. FMF patients in the attack period (n = 8) had significantly higher CRP, ESR, fibrinogen, and leukocyte levels (p < 0.001) than patients in the attack-free period (n = 12). The T-SH level (p < 0.05) was significantly higher and CuZn SOD activity was significantly lower (p < 0.05) in FMF patients in the attack period. The findings revealed upregulated APR during the attack period in FMF patients and enhanced oxidative stress in the FMF patients as compared to controls.     

Characterization of oxidative stress in various tissues of diabetic and galactose-fed rats

Rats fed a galactose-rich diet have been used for several years as a model for diabetes to study, particularly in the eye, the effects of excess blood hexoses. This study sought to determine the utility of galactosemia as a model for oxidative stress in extraocular tissues by examining biomarkers of oxidative stress in galactose-fed rats and experimentally-induced diabetic rats. Sprague-Dawley rats were divided into four groups: experimental control; streptozotocin-induced diabetic; insulin-treated diabetic; and galactose-fed. The rats were maintained on these regimens for 30 days, at which point the activities of catalase, glutathione peroxidase, glutathione reductase, and superoxide dismutase, as well as levels of lipid peroxidation and reduced and oxidized glutathione were determined in heart, liver, and kidney. This study indicates that while there are some similarities between galactosemic and diabetic rats in these measured indices of oxidative stress (hepatic catalase activity levels and hepatic and renal levels of oxidized glutathione in both diabetic and galactosemic rats were significantly decreased when compared to normal), overall the galactosemic rat model is not closely parallel to the diabetic rat model in extra-ocular tissues. In addition, several effects of diabetes (increased hepatic glutathione peroxidase activity, increased superoxide dismutase activity in kidney and heart, decreased renal and increased cardiac catalase activity) were not mimicked in galactosemic rats, and glutathione concentration in both liver and heart was affected in opposite ways in diabetic rats and galactose-fed rats. Insulin treatment reversed/prevented the activity changes in renal and cardiac superoxide dismutase, renal and cardiac catalase, and hepatic glutathione peroxidase as well as the hepatic changes in lipid peroxidation and reduced and oxidized glutathione, and the increase in cardiac glutathione. Thus, prudence should be exercised in the use of experimentally galactosemic rats as a model for diabetes until the correspondence of the models has been more fully characterized.     

Levels of plasma malondialdehyde and erythrocyte antioxidant enzyme activities in patients with chronic hepatitis B

BACKGROUND/AIMS: Hepatitis B virus infection, extensively seen throughout the world, can become highly chronic. Pathogenesis of chronic hepatitis is not yet known fully. It is shown that oxidative stress may play a role in pathogenesis and may regulate collagen synthesis and thus may contribute to the process of liver damage. This study is aimed at investigating the existence of oxidative stress in chronic hepatitis B cases and its relation with alanine aminotransferase and aspartate aminotransferase which are the serum indicators of liver damage; along with interaction of erythrocyte antioxidation enzyme activities in the same cases. METHODOLOGY: Eighty patients with chronic hepatitis B under follow-up, and 40 healthy volunteers were included in this study. In the control and patients groups, together with serological markers for viral etiology, alanine aminotransferase and aspartate aminotransferase levels; plasma malondialdehyde level; erythrocyte superoxide dismutase, glutathione peroxidase and catalase activities were analyzed. RESULTS: Malondialdehyde levels of chronic hepatitis B cases were statistically high compared to control group (p < 0.05). There was correlation between serum malondialdehyde levels and serum alanine aminotransferase, aspartate aminotransferase levels in the patient group (r = 0.324, p < 0.01, r = 0.273, p < 0.05). Average superoxide dismutase and catalase activities were found to be significantly low compared to control group (p < 0.001); average glutathione peroxidase activity were significantly high when considered statistically (p < 0.001). No correlation between serum alanine aminotransferase and aspartate aminotransferase levels and glutathione peroxidase, catalase and superoxide dismutase activities was found in the patients group (p > 0.05). CONCLUSIONS: In the study we showed that there is correlation between serum malondialdehyde level and alanine aminotransferase and aspartate aminotransferase levels of chronic hepatitis B patients. According to the results of our study, it might be thought that serum malondialdehyde level might be a marker of hepatocellular damage in chronic hepatitis B cases. We suggest that antioxidant treatment for chronic hepatitis B patients should be examined in future studies.     

Antioxidant potential in esophageal,stomach and colorectal cancers

BACKGROUND/AIMS: The gastrointestinal tract is particularly susceptible to reactive oxygen species attack which lead to carcinogenesis. An important role in defense strategy against reactive oxygen species is played by antioxidants. The present study aims at examining antioxidant parameters and malondialdehyde--the product of lipid peroxidation as well as the marker of cancer progression--and cancer procoagulant in esophageal, gastric and colorectal cancer patients. METHODOLOGY: The activity of superoxide dismutase, catalase, glutathione peroxidase and reductase and the level of glutathione, vitamin C, malondialdehyde and cancer procoagulant were determined in tumors and normal mucous from 18 patients with esophageal cancer, 18 patients with stomach tumor and 62 patients with colorectal cancer. RESULTS: In esophageal tumor the activity of all enzymes has been increased compared with normal mucous. Stomach tumor has been also characterized by an increase in antioxidant enzymes activity except glutathione peroxidase and reductase whose activities have been decreased. However in colorectal tumor the activity of enzymes has been increased apart from catalase. In all cases the glutathione level has been increased while the vitamin C content has been significantly decreased. Tumor malondialdehyde level was significantly increased, too. The level of cancer procoagulant also increased in cancer tissues as well as in the serum. CONCLUSIONS: Antioxidant potential in all cases of gastrointestinal tract cancer has been unbalanced which has lead to increase in reactive oxygen species action and enhancement of lipid peroxidation and cancer procoagulant generation.     

Oxidant/Antioxidant Status of the Erythrocytes from Patients with Rheumatoid Arthritis

It has been suggested that enzymatic and/or non-enzymatic antioxidant systems are impaired in rheumatoid arthritis (RA) and hence patients are exposed to oxidant stress. This study aimed to establish whether this is really the case. Fasting blood samples were obtained from 24 patients with rheumatoid arthritis and 20 controls. The activities of erythrocyte superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px) and xanthine oxidase (XO) enzymes and malondialdehyde (MDA), oxidant resistant (OR) and non-enzymatic superoxide radical scavenger activity (NSSA) values were measured in both groups. Patients with RA had higher SOD and XO activities and MDA levels than did the controls. However, NSSA and OR levels were found to be decreased, and CAT and GSH-Px activities unchanged in the study group. Results suggest that excessive free radical production through the xanthine–xanthine oxidase system is the primary factor in rheumatoid arthritis, rather than an impaired antioxidant system. The therapeutic use of XO enzyme inhibitors and some antioxidants can be beneficial in this regard. Received: 20 May 1999 / Accepted: 27 October 1999     

The role of free radicals in leaf senescence

Decreased catalase activity is a consistent feature of leaf senescence. Although not as well documented, superoxide dismutase appears generally to decrease during leaf senescence. These changes suggest that free radical levels are likely to be higher in senescing tissues. The hydrogen peroxide-scavenging ability of chloroplasts due to the activity of the enzymes ascorbate peroxidase, dehydroascorbate reductase and glutathione reductase appears to be established although there is no information on changes in levels of these enzymes in response to leaf senescence. In plants, unlike mammals, the direct reaction of glutathione with H2O2, catalysed by glutathione peroxidase, appears to be only a minor means of scavenging hydrogen peroxide. Senescence appears to be correlated with increases in lipid peroxidation and membrane permeability. The findings reviewed in this paper lend general support to the view that free radicals play a significant role in the multifactorial syndrome which constitutes leaf senescence.     

Oxidative stress in blood of patients with alcohol-related pancreatitis

To determine the possible role of oxidative stress in alcoholic pancreatitis, the authors measured the ability of blood neutrophils of 22 patients with acute and 20 patients with chronic alcoholic pancreatitis to produce superoxide anion (O2-) and hydrogen peroxide (H2O2), spontaneously and after in vitro stimulation with phorbol ester and compared it with that of neutrophils isolated from the blood of 16 healthy controls. In addition, they measured serum activities of superoxide dismutase, catalase, and the serum concentration of glutathione peroxidase (GPx). Phorbol ester-induced O2- and H2O2 production in neutrophils of patients with acute and chronic pancreatitis was greater than in controls, but these differences, except of superoxide anion production by neutrophils of patients with chronic pancreatitis, were not statistically significant because of large individual differences. Spontaneous resting production of O2- and H2O2 by neutrophils of patients with chronic pancreatitis was significantly greater than in the controls. Superoxide dismutase and catalase activity was greater in sera of both groups of patients with acute and chronic alcoholic pancreatitis than in controls, but GPx concentration was significantly less in the sera of patients with chronic pancreatitis. Impaired GPx production and increased production of O2- and H2O2 by neutrophils may result in increased lipid peroxidation and could play a role in the pathogenesis of chronic alcoholic pancreatitis.     

Lipid peroxidation and hyperuricemia in patients with ischemic heart disease

Lipid peroxidation, activity of the enzymatic link of the antioxidative system, and parameters of the lipid system were studied in 62 patients with coronary heart disease (27 patients with hyperuricemia and 35 subjects with normal uric acid levels) in relation to blood uric acid concentrations. The levels of uric acid, malonic dialdehyde, total lipids, total cholesterol, beta-lipoprotein cholesterol, triglycerides were measured and the activities of superoxide dismutase, catalase, glutathione peroxidase, and glutathione reductase were evaluated. In the patients there was an increase in lipid peroxidation and lipid composition changes which were more drastically marked in hyperuricemia.     

Aortic antioxidant defence mechanisms: time-related changes in cholesterol-fed rabbits

In 24 rabbits fed a hyperlipidic diet (0.5% cholesterol, 5% lard and 5% peanut oil) for 10 (group A1), 30 group B1) and 60 days, (Group C1), compared to 24 control rabbits fed a standard diet for the same periods, antioxidant defence system (total superoxide dismutase, catalase, total thiol compounds selenium-dependent and selenium-independent glutathione peroxidase, glutathione reductase, glutathione transferase) and lipid peroxidation (thiobarbituric acid-reactive substances) in the aortic wall were tested. The percent of intima with grossly apparent atherosclerosis, is assessed by staining with the lipophilic dye Sudan IV, was negligible in group A1, but increased progressively in groups B1 (22.7-6.7%) and C1 (56.8-8.8%). Compared to the controls, a significant rise in superoxide dismutase activity was observed after 30 days of hyperlipidic diet, with a further marked increase at 60 days. Total thiol compounds and selenium-dependent glutathione peroxidase activity rose progressively from 10 to 30 and 60 days in cholesterol-fed rabbits. On the contrary, catalase, glutathione reductase and glutathione transferase activities significantly decreased in all experimental groups. Selenium-independent glutathione peroxidase activity was not detectable. Thiobarbituric acid-reactive substances increased about 3 times in hyperlipidemic rabbits. In conclusion, the changes in aortic antioxidant defence mechanisms and lipid peroxidation precede the massive vascular lipid infiltration in cholesterol-fed rabbits; some antioxidant mechanisms are stressed (superoxide, dismutase, glutathione peroxidase, total thiol compounds), whereas others are depressed (catalase, glutathione reductase, and glutathione transferase), thus potentially reducing or increasing vascular susceptibility to oxidative injury.     

Hormonal and local factors influence antioxidant enzyme activity of rat fetal lung cells in vitro

Monolayer cultures of fetal rat mixed lung cells respond to sublethal concentrations (50%) of oxygen by a reduced growth rate. Exposure to 95% O2 causes growth arrest and cell loss. In the presence of serum the addition of dexamethasone (5.5 nM), tri-iodothyronine (5.5 nM), or insulin (5 microU/ml) appeared to increase the cytotoxicity of 95% O2. Under growth-arrested conditions, in the absence of serum or elevated O2 concentrations, all three agents influence cellular antioxidant enzyme activities. Dexamethasone (0.055 nM) increased CuZn superoxide dismutase activity by 72% and glutathione peroxidase activity by 94%. Triiodothyronine (5.5 nM) increased CuZn superoxide dismutase activity 93%. Insulin (5 microU/ml) increased CuZn superoxide dismutase activity 90%, and catalase activity 58%. Dexamethasone, but not tri-iodothyronine or insulin, seems to have a protective effect against subsequent acute hyperoxia under serum-free conditions. Local non-hormonal factors may also influence lung cell responses to acute increases in oxygen concentrations, since cells acutely exposed to 50% or 95% O2 release a transferable factor(s) into their culture medium which increases antioxidant enzyme activities of non-hyperoxic lung cells.     

Increased hydrogen peroxide formation in platelets of patients affected with essential thrombocythaemia (ET).

The basal platelet level of reactive oxygen species and their enhancement following stimulation by different agonists were determined in a selected group of patients with essential thrombocythaemia (ET). Activated platelets had lower levels of superoxide anion and higher intracellular concentrations of hydrogen peroxide than controls. Higher levels of lipid peroxidation induced by N-ethylmaleimide were also observed. Measurement of the most important enzymes generating and scavenging these reactive oxygen species revealed increased specific activities of NADPH-cytochrome c reductase and superoxide dismutase and a decrease in platelet catalase activity in patients with ET. Since an abnormal production of oxygen radicals seems to be implicated in various pathological conditions and aging processes, the increased amount of hydrogen peroxide found in platelets of patients could be involved in some of the platelet alterations described in ET.