Increased oxidative stress and decreased membrane fluidity in erythrocytes of CAD patients

Introduction Cardiovascular disease, as reported by The World Health Organization (WHO), is the largest contributor to global mortality and it is supposed to dominate mortality trends in the future (WHO [...]
One of many risk factors for cardiovascular disease appears to be oxidative stress. To estimate possible changes in redox balance, membrane fluidity, and cholesterol level in erythrocytes was collected erythrocytes from patients diagnosed with coronary artery disease (CAD). The study included 20 patients with previous myocardial infarction occurring more than 6 months prior to the time of screening with low-density lipoprotein cholesterol (LDL-C) >70 mg/dL and 21 healthy controls. The following parameters were studied: catalase, glutathione peroxidase (GPx), superoxide dismutase (SOD), thiobarbituric acid reactive substrates (TBARS), sulfhydryl (SH) groups in membrane protein, total cholesterol level, and erythrocyte membrane fluidity. Our study showed an increase in the level of lipid peroxidation (13%) and total cholesterol (19%), and a decrease in membrane fluidity (14%) in the subsurface layers and in the deeper layers of erythrocyte membrane (7%) isolated from patients with CAD in comparison to healthy controls. A significant decrease in catalase (10%) and SOD (17%) activities were also observed. No changes in GPx activity or the level of SH groups were observed. Our study indicates that there are disorders in the antioxidant system as well as changes in the membrane structure of erythrocytes obtained from CAD patients. Key words: coronary artery disease, lipid peroxidation, total cholesterol, membranes fluidity, antioxidant system. Le stress oxydant semble constituerun des nombreux facteurs de risque de developper une maladie cardiovasculaire. Nous avons ainsi decide d'evaluer le lien qui existe entre les changements possibles de l'equilibre redox, la fluidite membranaire et le niveau de cholesterol, dans des erythrocytes preleves de patients chez qui l'on a diagnostique une maladie coronarienne (MC). Cette etude impliquait 20 patients ayant presente un infarctus du myocarde au moins 6 mois avant la periode de selection et dont les LDL-C etaient > 70 mg/dl, et 21 sujets sains. Les parametres suivants ont ete etudies: activite des enzymes antioxydantes soit la catalase (CAT), la glutathion peroxydase (GPx), la superoxyde dismutase (SOD), les substrats reactifs a l'acide thiobarbiturique (TBARS), les groupes SH des proteines membranaires, le niveau de cholesterol total et la fluidite membranaire des erythrocytes. Notre etude a revele un accroissement de la peroxydation lipidique (13 %) et du cholesterol total (19 %), et une diminution de la fluidite membranaire (14 %) dans les couches sous la surface et de 7 % dans les couches plus profondes de la membrane des erythrocytes isoles de patients avec MC comparativement au groupe sain. Une diminution significative de l'activite de la CAT (10 %) et de la SOD (17 %) a aussi ete observee. Aucun changement d'activite de la GSH-Px ou de niveau de groupes SH n'a ete note. Notre etude a mis en evidence des perturbations du systeme antioxydant ainsi que des changements de la structure de la membrane des erythrocytes preleves de patients ayant re^u un diagnostic de MC. [Traduit par la Redaction] Mots-cles: maladie coronarienne, peroxydation lipidique, cholesterol total, fluidite membranaire, systeme antioxidant.