Endogenous and copper-induced lipid peroxidation and antioxidant activity of serum in hypercholesterolemic subjects

Endogenous malondialdehyde and diene conjugate levels were increased in hypercholesterolemic subjects with serum cholesterol levels above 240 mg/dl as compared to normocholesterolemic subjects (below 20 mg/dl). A decrease in vitamin E/cholesterol and vitamin C/cholesterol ratios was observed in serum of hypercholesterolemic individuals. However, the susceptibility of serum to copper-induced lipid peroxidation and antioxidant activity were found unchanged. The present study indicates that hypercholesterolemic subjects have a high level of circulating lipid peroxides and that a higher tendency towards atherosclerosis in these subjects may be related to increased baseline levels of serum lipid peroxides

Mitochondrial lipid peroxides and antioxidant enzymes in the liver following phorone-induced glutathione depletion

The levels of lipid peroxidation product (malondialdehyde = MDA) vitamin C and the activities of glutathione peroxidase (GSH-Px) dismutase (SOD) were determined in the liver and its mitochondrial fraction, in the rats 2 and 18 hr after the injection of phorone, a glutathione (GSH) depleting agent. GSH levels decreased in liver homogenate and its mitochondrial fraction after 2 hr of phorone treatment, but these values returned to normal levels at 18 hr. In GSH depleted conditions, hepatic vitamin C levels increased, GSH-Px and SOD activities remained unchanged in mitochondrial and post-mitochondrial fractions. These results indicate that GSH depletion per se does not influence lipid peroxidation and GSH-Px and SOD activities in the liver and the mitochondrial fraction

Evidence for oxidative stress in the hepatic mitochondria of bile duct ligated rats

Lipid peroxidation increased both in the liver homogenates and in the hepatic mitochondrial fraction of bile duct ligated (BDL)-rats. Although mitochondrial superoxide dismutase (SOD) activity did not change in the liver, glutathione (GSH) levels and glutathione peroxidase (GSH-Px) activity decreased in hepatic mitochondrial fraction of BDL-rats as compared to sham-operated rats. In addition, GSH-Px and glutathione transferase (GST) activities decreased but SOD activity remained unchanged in the post-mitochondrial fraction of the liver from BDL-rats. However, erythrocyte lipid peroxide and GSH levels did not change in BDL-rats. In conclusion, our results show that the disturbance of oxidant-antioxidant balance especially in mitochondria may be responsible for cholestatic injury in BDL-rats. (C) 1997 The Italian Pharmacological Society

Age-related changes in plasma lipid peroxidation and antioxidant system in humans and rats

This study was carried out on young (20-35 years) and old (60-85 years) men and rats (6 vs 22 months) to investigate the effect of aging on plasma lipid peroxidation and the antioxidant system. Plasma polyunsaturated fatty acid (PUFA), total fatty acid (TFA) and malondialdehyde (MDA) levels increased in aged humans and rats compared with young groups. However, plasma MDA/TFA ratios did not increase in aged humans and rats. Plasma vitamin E/TFA, and total thiol content were found to decrease both in aged humans and rats. Plasma antioxidant activity (AOA) decreased only in aged rats. In addition, the susceptibility of VLDL + LDL, apolipoprotein B containing lipoproteins to copper-induced peroxidation increased with aging. It is concluded that aging is associated with some variations in plasma oxidant-antioxidant balance. (C) 1997 Elsevier Science Ireland Ltd

PEROXIDATION POTENTIAL AND ANTIOXIDANT ACTIVITY OF SERUM IN PATIENTS WITH DIABETES-MELLITUS AND MYOCARD INFARCTION

Endogen malondialdehyde (MDA), diene conjugate levels, the susceptibility to copper-induced lipid peroxidation and antioxidant activity of serum were determined in patients with atherosclerotic diseases such as diabetes mellitus and myocard infarction. Lipid peroxidation susceptibility and antioxidant activity did not change, however, an increase in endogen MDA and diene conjugate levels was observed in serum of these patients, These results indicate the presence of oxidative stress in diabetes mellitus and myocard infarction

Artichoke Leaf Extract reduces Oxidative Stress and Lipoprotein Dyshomeostasis in Rats Fed on High Cholesterol Diet

Hypercholesterolemia and lipid peroxidation play complementary role in atherosclerosis. Artichoke leaf extract (ALE) is rich in natural antioxidants and has a cholesterol-reducing effect. However, there is no study investigating the effect of ALE on lipid levels and lipid peroxidation in experimental hypercholesterolemic conditions. Rats were fed on 4% (w/w) cholesterol and 1% (w/w) cholic acid supplemented diet for 1 month. ALE (1.5 g/kg/day) was given by gavage during the last 2 weeks. Serum lipid composition, malondialdehyde (MDA) and diene conjugate (DC) levels and plasma antioxidant activity (AOA) were measured. In addition, endogenous DC and copper-induced MDA levels were determined in apo B-containing lipoproteins (LDL+VLDL fraction). Serum cholesterol and triglyceride levels and the ratio of cholesterol to HDL-cholesterol decreased due to ALE treatment in rats fed on HC diet. Significant decreases in serum MDA and DC levels and increases in plasma AOA were detected in serum in ALE-treated hypercholesterolemic rats. Endogenous DC and copper-induced MDA levels were also lower in LDL+VLDL fraction due to ALE-treatment in hypercholesterolemic rats. Our results indicate that ALE may be useful for the prevention of hypercholesterolemia-induced pro-oxidant state in LDL+VLDL fraction and the reduction of increased serum cholesterol and triglyceride levels. Copyright (C) 2009 John Wiley & Sons, Ltd

Increased lipid peroxidation in serum and low-density lipoproteins associated with aging in humans

This study was carried out in 140 healthy subjects who were divided into three subgroups of age: young (21-40 years), mature (41-60 years), and elderly (61-85 years) to investigate lipid peroxides and the antioxidant system in serum and low-density lipoproteins (LDL). Serum levels of cholesterol and LDL cholesterol increased with age. The elderly group was found to have higher polyunsaturated fatty acid (PUFA) levels, thiobarbituric acid reactive substances (TBARS), diene conjugates, and lower cholesterol-adjusted vitamin E levels and antioxidant activity (AOA) as compared to the young group. No age-related difference was detected in serum vitamin C levels. Age correlated positively with serum cholesterol, LDL-cholesterol, PUFA, TBARS, diene conjugate levels and the susceptibility of LDL to copper-induced lipid peroxidation increased in elderly subjects as compared with young subjects. In addition, positive correlations were detected between age and LDL endogenous diene conjugate levels and TBARS formation after copper incubation. However, the susceptibility of whole serum to copper-induced lipid peroxidation did not change in young and elderly subjects. Our results show that endogenous lipid peroxide levels in serum and LDL, and the susceptibility of LDL to copper-induced oxidation, increased with aging in humans