Increased erythrocyte membrane arachidonate and platelet malondialdehyde (MDA) production in psoriasis: normalization after fish-oil.

Evidence exists of platelet activation and increased thromboxane B2 production in psoriasis. In 13 patients suffering from psoriasis, we determined the lipid composition of erythrocyte membrane, erythrocyte and platelet glutathione peroxidase activity (E-GSH-Px; Plt-GSH-Px), platelet MDA production and bleeding time. Compared with normal controls, psoriatics showed a significant increase in erythrocyte membrane arachidonic acid (AA) (p less than 0.001) and polyunsaturated fatty acids (PUFA) (p less than 0.001), platelet MDA production (p less than 0.01) and E- and Plt-GSH-Px activity (p less than 0.01; p less than 0.01). After 8 weeks of fish-oil supplementation (20 ml/day) we observed the following changes: a) marked amelioration of skin lesions; b) normalization of membrane lipid pattern and platelet MDA production; c) a further increase in E- and Plt-GSH-Px activity (p less than 0.01; p less than 0.01); d) significant prolongation of bleeding time (p less than 0.05). Our data demonstrate: 1) a generalized perturbation of membrane lipid pattern in psoriasis, characterized by an excess of AA; 2) an activation of AA metabolism in platelets suggested by increased MDA production and GSH-Px activity; 3) dietary fish-oil may normalize membrane lipid pattern and reduce platelet hyperactivity in psoriasis.