Increased membrane ratios of metabolite to precursor fatty acid in essential hypertension

Desaturase enzymes are responsible for the conversion of essential fatty acids to the longer-chain eicosanoid precursors. These enzymes require zinc as an essential cofactor, and the following ratios-C20:4/C18:2, C20:5/C18:3, and C22:6/C20:5-are considered indexes of their activity. We analyzed these parameters in plasma and erythrocyte membranes of 105 essential hypertensive patients, 20 white coat hypertensive patients, and 100 age-matched normotensive control subjects. Dietary analysis excluded significant quantitative and qualitative differences in fatty acid dietary intake between essential hypertensive patients and normotensive control subjects. Zinc levels and C20:4/C18:2, C20:5/C18:3, and C22:6/ C20:5 ratios were significantly higher in essential hypertensive patients than control subjects, whereas white coat hypertensive patients showed intermediate values for all these parameters. These data provide evidence for an alteration in fatty acid metabolism of essential hypertensive patients, consistent with increased activity of desaturase enzymes. The consequent greater bioavailability of eicosanoid precursors, and in particular of arachidonic acid, could affect several vascular functions and have a bearing on the pathogenesis or complications of hypertension.