ALTERATIONS IN SERUM PHOSPHATIDYLCHOLINE FATTY ACYL SPECIES BY EICOSAPENTAENOIC AND DOCOSAHEXAENOIC ETHYL-ESTERS IN PATIENTS WITH SEVERE HYPERTRIGLYCERIDEMIA

A new and sensitive method has been developed to analyze the molecular species of glycerophospholipids. This method was used to examine the effects of hypolipidemic intervention with n-3 fatty acids on the seru m phosphatidylcholine species in severely hypertriglyceridemic patient s. The drug treated group (n = 19) received 4 g/day of an 85% concentr ate of the ethyl eaters of eicosapentenoic and docosahexaenoic acids f or 6 weeks. Control patients (n = 21) received 4 g/day of ethyl esters of corn oil fatty acids. To evaluate the effects of n-3 fatty acids u pon serum phosphatidylcholines (PCs), sera from treated and control pa tients were analyzed before and after 6 weeks of intervention. PCs iso lated from sera were digested with phospholipase C to diglycerides, de rivatized with 7-methoxycoumarin-3-carbonyl azide, and analyzed by rev erse phase high performance liquid chromatography (HPLC) with fluoresc ence detection. Pre-intervention serum PC species were, in order of de creasing concentration C-16:0,C-18:2, C-16:0,C-18:1, C-18:0,C-18:2, C- 16:0,C-20:4, C-16:0,C-22:6, C-18:0,C-20:4, C-16:0,C-16:0, mean increas es of 300% in C-16:0,C-20:5 and of 160% in C-16:0,C-22:6 species were observed. There were no significant changes in the molecular species o f tile serum phosphatidylcholines in the group receiving the cor n oil ethyl esters. The cumulative relative percentages for each of the ind ividual Fatty acids measured by HPLC were comparable to those determin ed by gas-liquid chromatography (GLC). In the treated group plasma tri glycerides were reduced 26%, while they were increased by 7% in the pl acebo group. Our data showed that incorporation of eicosapentaenoic an d docosahexaenoic acid into the serum PCs occurred within 6 weeks prim arily in the C-16:0,C-20:5 and C-16:0,C-22:6 species and were usually accompanied by a reduction in plasma triglyceride.