Lipid peroxidation and protective enzymes during myocardial infarction.

Fasting blood taken from 34 patients with myocardial infarction, 19 with unstable angina and 40 healthy controls, was analysed for malondialdehyde and erythrocyte detoxification enzymes, superoxide dismutase and glutathione peroxidase. Malondialdehyde concentration was raised in the patients with myocardial infarction during the initial 48 h after an attack, and correlated with the severity of the attack. 12 days after the infarct, malondialdehyde concentrations were lower but still raised. Superoxide dismutase activity was below normal during the initial 48 h post infarct and raised twelve days after. Glutathione peroxidase was reduced after 12 days. Similar, but less marked changes were seen in the patients unstable angina.

The evolution of oxidative stress indicators in the course of myocardial ischemia.

Two studies were carried out in patients suffering from Unstable Angina (UA) and Myocardial Infarction (MI). The first study investigated the variations of the Malondialdehyde (MDA) rate at 1st, 5th, 12th day of treatment in 27 patients (15 UA and 12 MI), compared to 15 controls. This rate varied in a different way, with a first peak and a rapid decrease in UA, where it regularly decreases in MI. The second study focused on the variations of MDA, Superoxide Dismutase (SOD), Glutathion Peroxydase (GPX) rates at 2nd, 12th days in 53 patients (19 UA and 34 MI), compared to 35 controls. Here again, the rate of MDA was high on day 2 and decreased on day 12. The rate of GPX showed similar evolution while the SOD rate had an opposite evolution. These two studies confirm the evidence of oxidative stress in acute coronary deficiency.

Study of fatty acids in atheroma induced in rabbits by an atherogenic diet with or without silicon i.v. treatment.

Fifty-two rabbits were submitted for two months to an atherogenic diet with or without addition of silicon in the form of an I.V. silicon organic compound and compared to a control group of 21 rabbits. Out of the 26 rabbits receiving cholesterol alone, 23 showed atheromatous lesions; out of the 26 rabbits receiving cholesterol + silicon, only 8 had lesions. Free fatty acids, total fatty acids and esters were studied in the plasma and in the aorta. During atheroma, saturated fatty acids decrease, in particular 18:0, unsaturated fatty acids increase, in particular 18:1, 18:2, 20:4; with added silicon the variations are less important: in free fatty acids in plasma, there is a decrease of 20:4; in cholesterol esters in plasma and aorta an increase of 18:0 and a decrease of 18:2. There is a negative correlation between atheromatous lesions and myristic and stearic acids, and a positive correlation between oleic, linoleic and arachidonic acids and atheroma. Arachidonic acid, involved in phenomena of lipid peroxidation, decreased in the silicon treated rabbits.

[HDL2 and HDL3 cholesterol in men and women in different forms of hyperlipidemia without arterial involvement]. / Etude du cholestérol HDL2 et HDL3 chez l'homme et chez la femme dans différentes formes d'hyperlipidémies sans atteinte artérielle.

The investigation was carried out in one hand on 54 hyperlipidemic men without arterial injury compared to 54 normolipidemic men, on the other hand on 50 hyperlipidemic women compared to 50 normolipidemic women. The hyperlipidemic subjects were separated in IIa, IIb and IV groups, according to WHO classification. Lipoprotein's separation was carried out by sequently ultracentrifugation and HDL2-HDL3 were isolated at a solvant density of 1.125 and 1.21; cholesterol was measured by enzymatic method. We observed a significant decrease of: (Formula: see text) ratio in all hyperlipidemic subjects compared to controls; but no significant variation of HDL2 and HDL3 cholesterol appeared in the three groups of hyperlipidemic subjects compared to controls; on the other hand we noted a HDL2 cholesterol greater in women than in men and this fact seems to prove a favorable action of this fraction in preventing atherosclerosis. The (Formula: see text) ratio remains the most discriminant factor of hyperlipidemia, but the: (formula: see text) ratio seems interesting and HDL2 cholesterol is always higher in women during hyperlipidemia with high risk, IIa and IIb.

[Membrane lipid peroxidation in coronary insufficiency]. / Etude de la peroxydation lipidique membranaire au cours de l'insuffisance coronaire.

Malondialdehyde (MDA) as lipid peroxidation marker was studied in 27 patients with acute coronary insufficiency. Significantly elevated plasma levels as compared with controls were found in patients with myocardial necrosis and with preinfarction syndrome. No correlation was found between MDA and creatine phosphokinase, and a significant MDA decrease was observed at day 12: plasma MDA reached normal levels in the myocardial necrosis group. The MDA decrease was also significant in the preinfarction group, but the MDA level remained high in 4 patients with unstable angina. MDA is not a prognostic index. No correlation was found between MDA and plasma lipid levels or patients' ages. These data confirm that myocardial ischemia is associated with abnormal production of oxygen-derived free radicals which react with the membrane unsaturated fatty acids, resulting in toxic endoperoxides. This is thought to be one of the physio-pathological pathways which aggravate ischemic myocardial tissue damage.

[Fatty acid and lipid peroxidation in human atherosclerosis]. / Etude des acides gras et de la péroxydation lipidique au cours de l'athérosclérose humaine.

Plasma fatty acids and lipid peroxidation were studied in human atherosclerosis. Analysis of fatty acids in 16 controls and 32 hyperlipidemic patients showed, in the latter, a decrease in saturated fatty acids, especially palmitic and stearic acids, and an increase in unsaturated fatty acids, especially arachidonic acid. Compared to hyperlipidemic patients without arterial injury, patients with arterial injury exhibit a significant increase in malonaldehyde (MDA). In the former, MDA concentrations are significantly increased compared to controls. Therefore, peroxidation of unsaturated fatty acids may have a deleterious effect on arteries in atheroma, through the release of toxic endoperoxydes and the metabolization of arachidonic acid into thromboxane, which is a platelet aggregator. Lipid peroxidation can also be demonstrated in other diseases: we found very high MDA concentration in 11 alcoholic patients (alcoholic hepatitis, cirrhosis) and 6 patients with inflammatory conditions such as Crohn disease.