Background. Oxidative modification of lipoproteins, in particular LDL, is considered a crucial step in the development of early atherosclerotic lesions. The oxidability of lipoproteins determines their atherogenic potential. A reduced resistance of LDL to oxidation is observed e.g. in patients with hyperlipoproteinaemia, hypertension and diabetes mellitus. Some work indicates the possibility to influence the oxidability of lipoproteins in a favourable way by hypolipidaemic treatment. Methods and Results. 17 subjects with primary hypercholesterolaemia (phenotype IIA/IIB) was treated for six weeks with pravastin (20 mg/day). Before onset and after termination of treatment concentrations of plasma lipids and lipoproteins were assessed and parameters of lipid peroxidation of LDL lipoproteins evaluated by a modified method of assessment of conjugated LDL dienes according to Esterbauer. Treatment had a favourable effect on the lipid and lipoprotein profile (decline of total cholesterol by 24%, P < 0.01, LDL-C by 33%, P < 0.001, triglycerides by 18%, P < 0.05, apo in plasma by 16%, P < 0.05 and in LDL by 28%, P < 0.001, and a rise of the cholesterol concentration in HDL by 17%, P < 0.05). The authors observed also is significant prolongation of the lag time by 23% (P < 0.01) and a decline of the basal absorbance by 10% (P < 0.05). Conclusions. Pravastin administered for a period of six weeks, 20 mg/day, caused a marked hypolipidaemic effect as well as significant reduction of oxidation and oxidability of LDL in patients with hypercholesterolaemia.

        Key words: hypercholesterolaemia, lipoprotein, pravastin, lipid peroxidation of LDL, lag phase.