264-POS

Abstract

Objectives Because of the great diversity of human lipid species, discerning meaningful patterns in lipidomic data has proven daunting. Considering the function of lipid classes in maintaining cell membrane permeability and viscosity provides a tool to bring order to the chaos of lipidomic studies. Methods Literature search. Results Compared to controls, a decreased phosphatidyl choline (PC) to phophatidyl ethanolamine (PE) ratio is seen in preeclampsia, cold adaptation, and essential fatty acid deficiency lipidomics. Because PC tends to aggregate in a relatively impermeable lamellar pattern and PE in a more permeable hexagonal pattern, the altered sphingolipid ratios in these diseases may be interpreted as homeostatic responses to maintain membrane permeability. Cold adaptation occurs by remodeling phospholipids to reduce membrane stiffness. Lipids alter membrane flexibility in predictable ways: long-chain saturated fatty acids and trans fatty acids stiffen cell membranes, monounsaturated and medium-chain saturated fatty acids maintain moderate membrane viscosity, and polyunsaturated fatty acids increase membrane flexibility. Pulse wave velocity demonstrates that women with preeclampsia have significantly increased vascular stiffness, correlating positively with severity of disease. Dietary trans fatty acids are preferentially integrated into the sn-1 position of PCs, which contain PUFA at the sn-2 position; a rise in PC PUFAs is noted with diets enriched in trans fatty acids. Using metabolomics biomarkers, to predict preeclampsia in early pregnancy, long-chain PUFAs were found to be significantly increased in women destined to develop preeclampsia later in pregnancy compared to pregnant women who did not, therefore increasing the unsaturation index, a pattern similar to that of cold adaptation, but not found in essential fatty acid deficiency. Increased unsaturation index is positively correlated with increased oxidative stress, a known pathological element in preeclampsia. Conclusions Considering the effects of lipid species on membrane viscosity and permeability offers a novel means to interpret lipidomic studies. Disclosures N.R. Hart: None.