1318 HUMAN FETUS, A POTENTIAL SURFACTANT DONOR: ISOLATION 0F LUNG SURFACTANT FROM AMNIOTIC FLUID

Abstract

Trials of surfactant substitution are complicated by suboptimal performance of artificial surfactant and possible side effects of partially purified animal surfactant. To solve these problems, human lung surfactant (HS) was isolated from amniotic fluid (AF) from seven patients with term cesarean sections (CS) by differential and sucrose density gradient centrifugation and nylon mesh filtration. Up to 600 ml of bloodless AF was obtained during CS. The recovery of HS (disaturated lecithin marker) was 53±8%, one liter of AF yielding 75±16 mg of HS phospholipid. Properties of HS were compared to rabbit surfactant (RS) from alveolar lavage on modified Wilhelmy balance at 37°C. Lowest surface tension during compression [γmin (dynes/cm)], collapse rate at constant surface area [Kγ (1/min)] at γmin, compressibility [C (cm/dynes)] at 8-12 dynes/cm, and surface adsorption from subphase (γo-γ1) in 1, 2, and 15 min were measured: Both HS and RS were highly surface active. However, HS adsorbed to the surface faster than RS (*P<0.02). The sterile isolation yields large quantities of HS, that may be useful in surfactant therapy.