血せんと脂質に関する研究 Ｖ ＥＰＡの脂質および凝固系におよぼす影響について

Abstract

The purpose of the study was to investigate the effect of eicosapentaenoic acid (c20: 5, ω3; EPA) on the serum lipids and fatty acid profiles, platelet functions and coagulation systems.Highly concentrated (75%) EPA ethylester, which was isolated and purified from sardine oil, was given to 17 patients suffering from hyperlipoproteinemia and/or hypertension for at least 16 weeks. Daily doses of EPA were 0.9g in 6, 1.8g in 7 and 2.7g in 4 patients. Initial mean total cholesterol level (TC) was 270.9±45.0mg/dl and reduction rates of TC were 4.4% at 4 week-period, 5.8% at 8 week-period, 3.1% at 16 week-period and 6.4% at 12 month-period of the treatment. Triglyceride level fell significantly, 20.9% at 4 week-period, 13.0% at 16 week-period and 18.6% at 12 month-period. HDL-cholesterol did not significantly change throughout the treatment. Changes in plasma main fatty acid profiles were shown in fig 1. plasma EPA increased from 1.84mol% to 5.41mol% after 4 weeks and 4.77mol% after 16 weeks, while other polyunsaturated fatty acids except arachidonate inclined to decrease. Above all, plasma linoleate fell significantly after taking EPA. No correlation between ΔTG and Δlinoleate suggests that exogenous EPA bound mainly to β-position of triglyceride and phospholipids in competition with other polyunsaturated fatty acids.As for platelet functions, no significant changes in platelet adhesiveness and collagen induced aggregation were observed. 1μM ADP induced aggregation lowered from 46.6% in maximal amplitued before the treatment to 29.0% at 16 week-period, 7.1% at 6 month-period and 27.3% at 12 month-period. Over 5mol% of EPA in plasma inhibited ADP induced aggregation. Coagulability expressed by thromboelastogram tended to be reduced, however, prothrombin time, PTT, antithrombin III, α2 macroglobulin and α1 antitrypsin did not alter.In conclusion, EPA reduced both serum lipids and ADP induced aggregation, which would be favourable for the prevention of atherosclerotic thrombotic diseases.