Oxidant stress and essential fatty acids in patients with risk and established ARDS

Oxygen free radicals are important mediators of both physiological and path ological events. In acute lung injury, the activated lymphocytes stimulate tumor necrosis factor (TNF) and other cytokines. These lymphokines augment free radical generation by polymorphonuclear leukocytes (PMNLs), macrophage s and other cells which may ultimately produce acute respiratory distress s yndrome (ARDS). This is supported by our results presented here in that the re is a significant increase in lipid peroxidation products in patients wit h established ARDS. The amount of lipid peroxidation was significantly high er Pn the established ARDS group compared to patients who are at risk for A RDS. Nitric oxide concentrations were significantly decreased in establishe d ARDS compared to the control and those who are at risk for ARDS. Fatty ac id analysis of the plasma phospholipid fraction revealed a significant decr eased in linoleic acid, gamma-linolenic acid, dihomo-gamma-linolenic acid a nd arachidonic acid levels of n-6 series and alpha-linolenic acid, eicosape ntaenoic acid, docosa-hexanenoic acid of n-3 series. Patients who are at ri sk for ARDS have decreased levels of gamma-linolenic acid of the n-6 series , alpha-linolenic acid and eicosapentaenoic acid of the n-3 series. These r esults suggest that lipid peroxides and alteration in essential fatty acid metabolism may have a role in the pathogenesis of ARDS. (C) 2000 Elsevier S cience B.V. All rights reserved.