PS-280 Surface Film Fromation in Vitro By Infant And Therapeutic Surfactants: Role Of Surfactant Protein B

Background Essential surfactant properties include transfer to gas-liquid interface, reduction of surface tension and film replenishment during respiratory cycles. Objective To compare component-specific film formation properties of infant and therapeutic surfactants. Design/methods Using a multiwell fluorescence assay, we compared maximal fluorescence (Max), time to reach Max (tMax) and phospholipid concentration for ½ maximal signal (½Max) for calfactant (CAL), poractant (POR), beractant (BER), colfosceryl palmitate (COL), with surfactant from immature infants with RDS. Dose-response studies were performed for addition of SP-B, albumin and budesonide. Results Max and ½Max values for CAL were higher/similar to those of rat surfactant. There were significant differences between CAL and other therapeutic surfactants for Max (CAL >COL >POR >BER) whereas ½Max were similar except for COL. In surfactant from 39 infant tracheal aspirates, ½Max was inversely correlated with SP-B content (p = 0.001). Addition of SP-B to samples with low endogenous content ( Conclusions This assay reveals differences in film formation efficiency for therapeutic surfactants reflecting differences in SP-B content and lipid composition. Film formation by infant surfactant is strongly influenced by SP-B content. The findings support the key physiological role of SP-B and the safety of surfactant as anti-inflammatory drug vehicle.