Oleic Acid Reduces Oxidant Stress in Cultured Pulmonary Artery Endothelial Cells

Abstract

Altering the fatty acid composition of cultured porcine pulmonary artery endothelial cells (PAEC) modulates their susceptibility to oxidant stress. This study demonstrates that supplementing PAEC with oleic acid (18:lω9), but not γ-linolenic acid (18:3ω6), provided dose-dependent protection from hydrogen peroxide (H₂O₂)-induced cytotoxicity. It was hypothesized that 18:1 reduced PAEC susceptibility to oxidant stress by altering H₂O₂ metabolism. To test this hypothesis, confluent PAEC monolayers were treated with 100-200 μM H₂O₂ or control conditions 24 h after supplementation with 0.1 mM 18:1, 18:3, or vehicle for 3 h. Intracellular [H₂O₂] in control cells (14.4-29.0 pM), estimated from the rate of aminotriazole-mediated inactivation of endogenous catalase activity, increased following treatment with 200 μM H₂O₂ (19.0-37.3 pM). Supplementation with 18:1 attenuated increases in intracellular [H₂O₂] only in oxidant-exposed cells, whereas supplementation with 18:3 attenuated intracellular [H₂O₂] only in control cells. Supplementation with 18:1 or 18:3 tended to reduce or enhance PAEC lipid hydroperoxide content following H₂O₂ exposure, respectively, but did not alter PAEC reduced glutathione content, the activities of glutathione peroxidase or catalase, or H₂O₂ uptake and release. Alteration of H₂O₂ metabolism in cultured PAEC may contribute to the ability of fatty acids to modulate cellular oxidant susceptibility.

Key Words:

• endothelial cell
• fatty acids
• hydrogen peroxide
• oleic acid
• oxidants