Vitamin E attenuates the injurious effects of bioactive phospholipids on human ciliated epithelium in vitro

Bioactive phospholipids (PL), particularly lysophosphatidylcholine (LPC). a re being increasingly implicated in the pathogenesis of various acute and c hronic inflammatory disorders. particularly those of the airways, while the re is emerging evidence that vitamin E may function as a natural antagonist of these lipid mediators of inflammation. The aims of this study were to d ocument the effects of vitamin E on the inhibition of ciliary beating and d amage to structural integrity of human ciliated epithelium induced by the P L, platelet-activating factor (PAF), lyso-PAF and LPC in vitro in relation to the anti-oxidative and membrane-stabilizing properties of the vitamin. Ciliary beat frequency was measured by a phototransistor technique, and dam age to structural integrity assessed by a visual-scoring index, while super oxide production by polymorphonuclear leukocytes and membrane-stabilizing p otential were measured using lucigenin-enhanced chemiluminescence and haemo lytic procedures, respectively. All three PL caused inhibition of ciliary beating and structural damage to human ciliated epithelium by membrane-directed cytotoxic mechanisms. which were potentiated by human polymorphonuclear leukocytes due to induction of oxidant-mediated injury. Both direct and phagocyte-inflicted epithelial inj ury was attenuated by vitamin E. In haemolytic and chemiluminescence assays . vitamin E neutralized both the membrane-destabilizing and pro-oxidative a ctions of all three PL, while spectrophotometric analysis of mixtures of vi tamin E with PAF, lyso-PAF and LPC revealed alterations in pe ak intensity, as well as peak shifts, indicative of physicochemical interactions between the vitamin and the PL. Vitamin E status may be a determinant of susceptibility to phospholipid-med iated airway inflammation and damage.