SLOŽENÍ MASTNÝCH KYSELIN A PARAMETRYLIPOPEROXIDACE VLDL A LDL U OSOB S DYSLIPIDÉMIÍ

Fatty Acid Composition andParameters of Lipoperoxidation of VLDL and LDL in Subjects wit Dyslipidaemia

Background.
Oxidatively modified LDL play an important role in the pathogenesis of endothelial dysfunction,initiation and development of atherosclerosis and stability of the atheromatous plaque. The increased oxidativestress is apparent from a number of deviations, which are part of the insulin resistance syndrome (hypertension,hypoalphacholesterolaemia, diabetes and hyperlipoproteinaemia). The objective of the work was to examine thedegree of oxidation and oxidability of LDL and VDL in subjects with dyslipidaemia.Methods and Results. In 40 subjects with dyslipidaemia, defined as a triglyceride concentration above 2.30mmol/l and a drop of HDL cholesterol below 0.90 mmol/l, the authors assessed the fatty acid profile in plasma li-pid classes and LDL by capillary gas chromatography. Lipoperoxidation in VLDL and LDL was examined by themethod of kinetics of conjugated dienes according to Esterbauser. The results were compared with a group of he-althy controls. The group of dyslipidaemic subjects had higher concentrations of NEFA, IRI, blood sugar anduric acid. In these subjects the concentration of conjugated dienes in VLDL was significantly higher and the lagstage in VLDL and LDL was reduced. Both groups differed as to the composition of VLDD and LDL. The groupof dyslipidaemic subjects had a higher concentration of cholesterol, phospholipids, triglycerides and apolipoprotein B.A constant finding in the fatty acid profile of all lipid classes was a raised concentration of palmitoleic acid and reduced li-noleic acid concentration.Conclusions. Dyslipidaemic subjects have, as compared with a control group, higher NEFA, IRI and uric acidconcentrations. Furthermore they differed not only by the composition of VLDL and LDL but also by a higher de-gree of VLDL oxidation and reduced resistance to lipoperoxidation of VLDL and LDL particles. A consistent fin-ding in the fatty acid profile was an increased level of palmitoleic acid in all plasma lipid classes and LDL anda drop of linoleic acid in phosphatidylcholine LDL and plasma cholesterolesters.

Key words:
lipoperoxidation, hypertriglyceridaemia, hypoalphacholesterolaemia, conjugated dienes VLDLand LDL, fatty acid profile, composition of VLDL and LDL, insulin resistance syndrome.