Abnormal lipoprotein phospholipid composition in patients with essential hypertension Original Research Article

Vascular cell membranes from patients with essential hypertension (EH) and animals with genetic forms of hypertension have been found to have alterations in the content of free cholesterol and negatively charged phospholipids that may modify their function. Since membrane and lipoprotein lipids exchange freely, the lipid composition of lipoproteins may be an indirect measure of the content of vascular and other cells. To determine whether abnormalities are present in the lipid and phospholipid composition of lipoproteins from patients with EH, 30 EH (11 women; 19 men) and 20 normotensive control subjects were studied. Since significant gender differences were present in a number of parameters of lipoprotein composition, male and female data were examined separately. The EH group of both sexes tended to have higher plasma TG and VLDL + LDL and HDL2 lipid levels than their respective controls. Not only were the calcium-binding phospholipids phosphatidylinositol (PI) + phosphatidylserine (PS), and the membrane fluidizer phosphatidylethanolamine (PE) significantly reduced in their VLDL + LDL, but all phospholipids (L, sphingomyelin (SPH), PI + PS, and PE) were significantly reduced relative to their neutral lipid content in both the HDL2 and HDL3 subfractions. These directional changes in lipoprotein FC and phospholipid in the EH women significantly increased the EH FC/PC (mol/mol) ratio in their plasma, a new cardiovascular risk factor, (EH 1.08 ± 0.22 vs. control 0.86 ± 0.08; P < 0.01) and lowered the SPH/PC ratio of HDL2 and HDL3 in EH patients of both sexes. These findings show that lipoproteins in normolipidemic EH women are relatively enriched in FC and in EH patients of both sexes depleted in certain phospholipids. If membranes of vascular tissues in EH are deficient in the same negatively charged phospholipids lacking in lipoproteins, their functional properties could be altered and vascular tone increased.