Activation of peroxisomal acyl-CoA oxidase and lipid peroxidation in the rat myocardium as affected by prolonged administration of ethanol

The influence of chronic alcoholic intoxication on the activity of peroxisomal acyl-CoA oxidase and antioxidative defensive enzymes (catalase, glutathione reductase, glutathione-S-transferase, superoxide dismutase, glucose-6-phosphate dehydrogenase) was studied in the rat myocardium. The parameters of lipid peroxidation in cardiomyocytes (the level of spontaneous chemiluminescence, accumulation of thiobarbituric acid-reactive material), as well as reduced glutathione content were also examined. The data obtained suggest that ethanol-induced activation of lipid peroxidation in the myocardium may be due to the elevation of hydrogen peroxide-generating activity of peroxisomes.     

Disorders of myocardial morphology in rats after 20-week alcoholization and 6-week abstention

The model experiment with rats was undertaken to assess a reversibility of alcoholic cardiomyopathy (ACMP). Certain features of ACMP were reproduced after 20 weeks of alcoholization. The following 6 weeks of abstinence were not enough for disappearance of structural alterations in the myocardium.     

Experimental assessment of the role of acetaldehyde in alcoholic cardiomyopathy

Alcoholism is one of the major causes of non-ischemic heart damage. The myopathic state of the heart due to alcohol consumption, namely alcoholic cardiomyopathy, is manifested by cardiac hypertrophy, compromised ventricular contractility and cardiac output. Several mechanisms have been postulated for alcoholic cardiomyopathy including oxidative damage, accumulation of triglycerides, altered fatty acid extraction, decreased myofilament Ca²⁺ sensitivity, and impaired protein synthesis. Despite intensive efforts to unveil the mechanism and ultimate toxin responsible for alcohol-induced cardiac toxicity, neither has been clarified thus far. Primary candidates for the specific toxins are ethanol, its first and major metabolic product — acetaldehyde (ACA) and fatty acid ethyl esters. Evidence from our lab suggests that ACA directly impairs cardiac function and promotes lipid peroxidation resulting in oxidative damage. The ACA-induced cardiac contractile depression may be reconciled with inhibitors of Cytochrome P-450 oxidase, xanthine oxidase and lipid peroxidation Unfortunately, the common methods to investigate the toxicity of ACA have been hampered by the fact that direct intake of ACA is toxic and unsuitable for chronic study, which is unable to provide direct evidence of direct cardiac toxicity for ACA. In order to overcome this obstacle associated with the chemical properties of ACA, our laboratory has used the chronic ethanol feeding model in transgenic mice with cardiac over-expression of alcohol dehydrogenase (ADH) and anin vitro ventricular myocyte culture model. The combination of bothin vivo andin vitro approaches allows us to evaluate the role of ACA in ethanol-induced cardiac toxicity and certain cellular signaling pathways leading to alcoholic cardiomyopathy. Published: February 17, 2003     

Experimental data on the mechanism of development of alcoholic cardiomyopathy

A study was made of histo- and ultrastructure and of some electron-histochemical characteristics of the myocardium and liver of alcoholic rats. Experimental animals manifested alterations in the myocardium which were similar to those seen in alcoholic cardiomyopathy in humans. In controls, such alterations were either lacking or occurred in rare cases. Rats which received ethanol showed fatty dystrophy of the liver. The experimental animals differed from controls in some morphometric parameters (body and heart weight, diameter of cardiomyocytes) as well.     

当归水提液和醇提液体外抗脂质过氧化和红细胞溶血作用

研究当归水提液和醇提液对小鼠肝组织自发性过氧化酯质分解产物丙二醛（malondialdehyde,MDA）的生成和对红细胞膜脂质过氧化及红细胞溶血作用的影响。采用TBA比色法测定肝组织匀浆MDA生成,分光光度法测定过氧化氢诱导红细胞膜脂质过氧化和溶血。实验分为空白组、对照组、加药组。加药组分为25、50、100和200mg/mL四个浓度组。当归水提液和醇提液均在25～200mg／mL的浓度范围内,能够明显抑制小鼠肝组织匀浆自发性MDA的生成,具有抑制过氧化氢诱导红细胞膜脂质过氧化和溶血的作用,抑制效果随当归水提液和醇提液浓度的增大而逐渐增强,抑制率与药物浓度成良好的量效关系。当归水提液和醇提液具有抗脂质过氧化和红细胞溶血的作用。     

Alterations in myocardial cardiolipin content and composition occur at the very earliest stages of diabetes: a shotgun lipidomics study

Recently, we have identified the dramatic depletion of cardiolipin (CL) in diabetic myocardium 6 weeks after streptozotocin (STZ) injection that was accompanied by increases in triacylglycerol content and multiple changes in polar lipid molecular species. However, after 6 weeks in the diabetic state, the predominant lipid hallmarks of diabetic cardiomyopathy were each present concomitantly, and thus, it was impossible to identify the temporal course of lipid alterations in diabetic myocardium. Using the newly developed enhanced shotgun lipidomics approach, we demonstrated the dramatic loss of abundant CL molecular species in STZ-treated hearts at the very earliest stages of diabetes accompanied by a profound remodeling of the remaining CL molecular species including a 16-fold increase in the content of 18:2-22:6-22:6-22:6 CL. These alterations in CL metabolism occur within days after the induction of the diabetic state and precede the triacylglycerol accumulation manifest in diabetic myocardium. Similarly, in ob/ob mice, a dramatic and progressive redistribution from 18:2 FA-containing CL molecular species to 22:6 FA-containing CL molecular species was also identified. Collectively, these results demonstrate alterations in CL hydrolysis and remodeling at the earliest stages of diabetes and are consistent with a role for alterations in CL content in precipitating mitochondrial dysfunction in diabetic cardiomyopathy.     

Effect of electromagnetic radiation of the decimetric wave range on myocardium cell membranes

The decrease in the rate of lipid peroxidation and the increase in te fluorescence of chlortetracycline, bound with calcium ions absorbed on membrane surface after exposure thereof to decimeter waves, were revealed in myocardium cell membranes. Opposite changes were observed after the effect of p- chlormercuribenzoate . The effect of decimeter waves compensated the p- chlormercuribenzoate -induced changes.     

Antioxidant and prooxidant action of nitric oxide donors and metabolites

It has been shown that various nitric oxide donors and metabolites have similar effects on lipid peroxidation in rat myocardium homogenate. The formation of malondialdehyde, a secondary product of lipid peroxidation, was inhibited in a dose-dependent manner by PAPA/NONO (a synthetic nitric oxide donor), S-nitrosoglutathione, nitrite, and nitroxyl anion. The inhibition of lipid peroxidation was provided most efficiently by the administration of dinitrosyl-iron complexes with dextran and PAPA/NONO. S-nitrosoglutathione also inhibited the destruction of coenzymes Q9 and Q10 during free radical oxidation of myocardium homogenate. Low-molecular-weight dinitrosyl iron complexes with cysteine also promoted lipid peroxidation, which is probably due to iron release during the destruction dinitrosyl iron complexes. It is likely that the antioxidant action of nitric oxide derivatives is related to the reduction of ferry forms of hemoproteins and interaction of nitric oxide with lipid radicals.     

Oxidative stress in the alcoholic liver disease

Parameters reflecting oxidative stress (OS) have been studied in 37 patients with alcoholic liver disease (ALD) during admission to the hospital and 2 weeks after the beginning of therapy. The patients were divided into 3 groups: alcoholic hepatitis (AH), alcoholic cirrhosis with hepatic insufficiency (the group C by the Child-Paquet scale) and terminal stage patients (subsequently died). All patients were characterized by a significant increase in plasma products of lipid peroxidation (conjugated diene and malondialdehyde) and a decrease of the ceruloplasmin level. The coefficient C OS significantly exceeded normal values both on admission and after the 2-week course of traditional therapy. This suggests an important role of the OS with ALD.     

Post-intoxication hypothermia and processes of free radical lipid peroxidation in the rat brain and heart in organophosphorus cholinesterase inhibitor poisoning]

The activity of lipid peroxidation (LP) of the brain and myocardium as well as the intensity of the body hypothermia during 30 days after a single introduction of poisons at a dose < D50 were studied on the models of induced toxicosis in rats due to two organophosphorus compounds (malathion and armin). It has been established that the maximums of diene conjugates and Schiff's bases accumulation in the rat organs poisoned with malathion and the intensity of hypothermic response on days 14 and 21 after intoxication coincided. The similar elevated lipid peroxidation was associated with esophageal hypothermia on day 14 after armin administration. Therefore, because of hypothermia, the influence of organophosphorus compounds on lipids of the rat brain and heart in the post-intoxication period may include the free radical ways of their peroxidation.     

Final products of lipid peroxidation in various liver diseases of alcoholic etiology

The content of lipid peroxidation products in the plasma of patients with various forms of alcohol-induced liver disorders was investigated. Plasma levels of lipid hydroperoxides in this group of patients were found to be the same as in healthy controls. Plasma content of fluorescent products of lipid oxidation was significantly elevated in patients suffering from acute alcoholic hepatitis and active alcoholic liver cirrhosis, and especially in patients with edematoascitic syndrome. The dynamics of fluorescent product plasma level reduction significantly correlated with the improvement of clinical status in the treatment of abstinent patients.     

Effect of chronic ethanol treatment under partial catalase inhibition on the activity of enzymes related to peroxide metabolism in rat liver and heart

1. In order to test the hypothesis that the alcoholic cardiomyopathy under partial catalase inhibition is associated with the activation of lipid peroxidation in cardiomyocytes (Panchenko et al., Experientia 43, 580-581, 1987), the effects of ethanol and catalase inhibitor 3-amino-1,2,4-triazole (aminotriazole) on rat heart and liver content of reduced glutathione and on the activity of enzymes related to peroxide metabolism: catalase, superoxide dismutase, glutathione peroxidase, glutathione reductase, glutathione-S-transferase and glucose-6-phosphate dehydrogenase were investigated. 2. In accordance with the data obtained by Kino (J. molec, cell. Cardiol. 13, 5-12, 1981), when ethanol (36% of dietary calories) and aminotriazole were simultaneously administered an alcoholic cardiomyopathy developed while in the liver moderate fatty degeneration was revealed. 3. Chronic combined or separate administration of ethanol and aminotriazole was shown to increase glutathione concentration and glutathione-S-transferase activity in rat liver. In the groups of animals which received isocaloric carbohydrates in the diet instead of ethanol the liver glucose-6-phosphate dehydrogenase was increased. 4. Acute and chronic aminotriazole injections led to catalase inactivation and in the latter case also to inhibition of the liver superoxide dismutase and glutathione peroxidase activities. 5. Ethanol and aminotriazole treatment did not alter the glutathione level and the activity of all enzymes tested (except catalase) in rat myocardium.     

Effect of chronic ethanol, catalase inhibitor 3-amino-1,2,4-triazole and clofibrate treatment on lipid peroxidation in rat myocardium

1. The effect of chronic alcohol consumption, catalase inhibitor 3-amino-1,2,4-triazole (amino-triazole) and peroxisome proliferator clofibrate on the level of Fe/ADP-ascorbate-induced lipid peroxidation has been studied in the rat myocardium. The intensity of lipid peroxidation was measured using chemiluminescence technique and malondialdehyde formation. 2. Combined us well as separate treatment with ethanol (36% of dietary calories) and aminotriazole caused elevation of the rate of lipid peroxidation in the nuclear-free homogenate or total particulate fraction of the rat heart. The most pronounced effect was noted during combined application of ethanol and aminotriazole. 3. Prolonged clofibrate treatment significantly increased the level of nonenzymatic lipid peroxidation in the rat myocardium. 4. Peroxidative alteration of the myocardial lipids in vivo was evaluated by measurement of conjugated dienes (absorbance at 233 nm). Separate ethanol, aminotriazole or clofibrate treatment did not affect the level of u.v. absorption of lipids from the total particulate fraction. However, when ethanol and aminotriazole were administered simultaneously an increase of conjugated diene formation was observed. 5. The data obtained confirm the hypothesis that ethanol or clofibrate-induced activation of the myocardial lipid peroxidation may be due to the increase of hydrogen peroxide-generating capacity of the heart microperoxisomes.     

Antioxidant activity of selected Indian spices

Spices and vegetables possess antioxidant activity that can be applied for preservation of lipids and reduce lipid peroxidation in biological systems. The potential antioxidant activities of selected spices extracts (water and alcohol 1:1) were investigated on enzymatic lipid peroxidation. Water and alcoholic extract (1:1) of commonly used spices (garlic, ginger, onion, mint, cloves, cinnamon and pepper) dose-dependently inhibited oxidation of fatty acid, linoleic acid in presence of soybean lipoxygenase. Among the spices tested, cloves exhibited highest while onion showed least antioxidant activity. The relative antioxidant activities decreased in the order of cloves, cinnamon, pepper, ginger, garlic, mint and onion. Spice mix namely ginger, onion and garlic; onion and ginger; ginger and garlic showed cumulative inhibition of lipid peroxidation thus exhibiting their synergistic antioxidant activity. The antioxidant activity of spice extracts were retained even after boiling for 30 min at 100 degrees C, indicating that the spice constituents were resistant to thermal denaturation. The antioxidant activity of these dietary spices suggest that in addition to imparting flavor to the food, they possess potential health benefits by inhibiting the lipid peroxidation.     

Role of monoaminoxidase in the intensification of peroxidation of lipids in mitochondria during experimental myocardial necrosis

The relationship between lipid peroxidation and rat heart mitochondrial monoamine oxidase activity was studied in experimental myocardial necrosis induced by adrenaline injection. It has been established that both the intensity of peroxidation and the activity of monoamine oxidase in mitochondria from adrenaline-injured rat myocardium were essentially increased. The preliminary administration of antioxidants (vitamin E and ionol) was shown to decrease both the intensity of lipid peroxidation and the activity of monoamine oxidase. It is suggested that intensification of lipid peroxidation which is considered to be the main pathogenic factor in ischemic myocardial injury depends on mitochondrial monoamine oxidase activity. Protective effects of antioxidants are realized by the action on two subsequent chains during the formation of active oxygen forms and destruction of lipid peroxidation products.     

Quantitative histoenzymological characteristics of the myocardium in sudden cardiac death

Enzymes in the human myocardium following sudden death were examined for activity in a quantitative histoenzymological study, these were NAD-dependent dehadrogenases of succinate (SDG), lactate (LDG), beta-hydroxybutyrate (beta-HOBDG), alpha-glycerophosphate (alpha-GPDG), alcohol (ADG), glucoso-6-phosphate (G-6-PDG), and NAD-diaphorase (NADse), and catalase. Autopsies were performed within 3 h after death. beta-HOBDG and LDG were found to show an increase in activity in the cardiomyocytes of sudden death subjects with coronary heart disease without apparent changes. In the myocardium from death subjects with coronary heart disease and large postinfarct cardiosclerosis, the activity of the enzymes was directly related to the severity of myocardial hypertrophy and signs of chronic heart failure. As myocardial hypertrophy developed, the enzyme activity increased; when there appeared signs of chronic heart failure it decreased. The myocardium from sudden death subjects with alcoholic cardiomyopathy showed diminished redox enzyme activity and higher activity of the enzyme utilizing alcohol (ADG and catalase). The findings suggest that changes in the enzyme activity in the myocardium are of various type and depend on previous cardiac abnormalities.     

Lipid peroxidation and antioxidant enzyme activities in erythrocytes of type I and II alcoholics

Reduced and oxidized glutathione (GSH and GSSG), protein-bound glutathione, lipid peroxidation and antioxidant enzyme activities were determined in the erythrocyte lysates and membranes of type I and II alcoholics in order to clarify the effect of age-of-onset and the duration of the alcohol consumption on erythrocyte oxidant and antioxidant status. The osmotic fragility and susceptibility of the erythrocytes to haemolysis were also determined. Erythrocyte lipid peroxidation was significantly increased but, GSH and protein-bound GSH, GSH/GSSG ratio and antioxidant enzyme activities were markedly decreased in the erythrocytes of the alcoholic subgroups. Erythrocyte count and haemoglobin content in the blood of alcoholics were found to be decreased in accordance with the finding that erythrocytes were more fragile and less resistant to haemolysis particularly in type II alcoholics. The present study showed that ethanol-induced oxidative stress in erythrocytes can lead to haemolysis and membrane-specific injuries in erythrocytes of the alcoholic subtypes.     

Plasma phosphatidylcholine hydroperoxide as a new marker of oxidative stress in alcoholic patients

Quantitative analysis of plasma phosphatidylcholine hydroperoxide (PCOOH) is an important step in evaluating the biochemical processes leading to oxidative injury. However, secondary products of lipid peroxidation are now used as indices. One hundred nine alcoholic patients, aged 22-81 years (mean +/- SEM, 52.0 +/- 1.3 years), and 21 healthy volunteers, aged 41-79 years (51.2 +/- 2.2 years), participated in this study. Plasma PCOOH was measured by HPLC with chemiluminescence detection. Plasma PCOOH concentration was significantly higher in alcoholic patients (46.1 +/- 4.1 pmol/ml) than in controls (15.6 +/- 1.8 pmol/ml). It was significantly higher in patients with blood alcohol (88.0 +/- 10.5 pmol/ml) than in those without alcohol (32.6 +/- 3.1 pmol/ml). The patients with high levels of aspartate aminotransferase, alanine aminotransferase, gamma-glutamyl transpeptidase (gamma-GTP), and triglyceride (TG) showed significantly higher PCOOH concentrations than did patients with normal levels. The PCOOH level was positively correlated with levels of gamma-GTP, HDL, blood alcohol concentration, and TG. Plasma PCOOH levels in 29 alcoholic patients after a 6 week abstinence were decreased significantly (22.8 +/- 11.1 pmol/ml), which was associated with improvement on liver function tests. This is the first measurement of plasma PCOOH in alcoholic patients. These results suggest the involvement of lipid peroxidation in alcohol-induced liver damage and confirm that the PCOOH plasma concentration is a new marker of alcohol consumption as well as oxidative stress in alcoholic patients.     

Antioxidant and prooxidant action of nitric oxide donors and metabolites

Different nitric oxide donors and metabolites proved to have similar effects on the peroxidation in rat myocardium homogenate. PAPA-NONOate (synthetic nitric oxide donor), S-nitrosoglutathione, nitrite, and nitroxyl anion caused dose-dependent inhibition of the formation of malonic dialdehyde, a secondary product of lipid peroxidation. Dextran-bound dinitrosyl iron complexes and PAPA-NONOate were the most efficient inhibitors of lipid peroxidation. S-Nitrosoglutathione also inhibited the decline in coenzymes Q₉ and Q₁₀. Low-molecular-weight dinitrosyl iron complexes with cysteine accelerated lipid peroxidation, which could be caused by the release of iron ions upon their destruction. The antioxidant effect of nitric oxide donors appears to be due to the reduction of hemoprotein ferryl forms and the reaction of nitric oxide with lipid radicals.     

Lipid levels and lipid peroxidation in frog tissues during hyperthermia and hibernation

The content of cholesterol, phospholipids, free fatty acids in the blood, ketone bodies and lipid peroxidation in the liver, brain, myocardium, skeletal muscles of Rana ridibunda were studied. Changes in the lipid content in blood during artificial hypothermia differ from those during hibernation and arousal. The utilization of reserve fats during hibernation is limited, but significantly rises during arousal. The ability to spontaneous lipid peroxidation under conditions of homogenate incubation at 37 degrees C does not increase in the studied tissues during hibernation.