Lipid compounds of the umbilical cord artery and their alterations in preeclampsia

The lipid composition of arterial walls changes during development, ageing and pathological processes. Preeclampsia is the most common pregnancy-associated pathological syndrome. It is accompanied by significant remodelling of the extracellular matrix, both in the umbilical cord vessels and in the surrounding Wharton's jelly. Lipids of the umbilical cord have not been extensively studied. Here we evaluate the lipid composition of the umbilical cord artery (UCA) and its alteration in preeclampsia. Thin layer chromatography and high-performance liquid chromatography were employed for these analyses. It was found that the UCA wall, as with most human tissues, contains free fatty acids, mono-, di- and triacylglycerols, free cholesterol and its esters. The characteristic feature of the UCA wall is the presence of high amounts of long chain polyunsaturated fatty acids (PUFA), including eicosapentaenoic acid (C20:5) and docosahexaenoic acid (C22:6), which are rather minor lipid components of most human tissues. They exist both in a free form and in a form of acylglycerols and cholesterol esters. Preeclampsia is associated with a marked decrease in most free fatty acids and acylglycerols. The total amount of long chain PUFA: C18:2, C:18:3, C20:4, C20:5 and C22:6 in these lipid fractions is decreased by half, with a concomitant increase in free cholesterol and its esters. We propose that these lower levels of PUFA may reduce prostaglandin synthesis in the arterial wall and thereby impair blood flow in the foetal vascular system, leading to preeclamptic symptoms.