Sensitivity of synthetic surfactants to albumin inhibition in preterm rabbits

Surfactant can be inhibited in vivo by plasma proteins invading the alveola r space during acute lung injury. The resistance? to protein inhibition of surfactant preparations with various synthetic surfactant proteins B and C (B and C) was tested in preterm rabbits. Surfactants consisted of a palmiti c acid containing phospholipid mixture (PL) with full-length SP-B peptide ( B1-78), one of two SP-B mutants (Bserine and BR236C), the synthetic SP-B mi mic KL4 (UCLA-KL4), a natural SP-B (Bbovine), synthetic palmitoylated SP-C peptide (C1-35), a combination of B1-78 + C1-35, a combination of BW236C C1-35, and the: clinical surfactant Survanta. Preterm rabbits born at 28 da ys of gestation were ventilated and received 100 mg/kg of albumin intratrac heally at 30 min and 100 mg/kg of surfactant at 45 min after birth, Dynamic lung compliance (tidal volume/mean airway pressure) decreased from 0.82 to 0.51 mL/kg/cm H2O after albumin instillation and to 0.43 mL/kg/cm H2O over a 60-min period after saline placebo. Treatment with B1-78 + C1-35 and BR2 36C + C1-35 surfactant and Survanta returned dynamic compliance to prealbum in values, B1-78, BR236C, Bbovine, and C1-35 surfactant stabilized dynamic compliance, but FL, Bserine, and UCLA-KL4 surfactant were unable to prevent a further deterioration in dynamic compliance. These data suggest that a c ombination of synthetic surfactant peptides B1-78 and C1-35 and the clinica l surfactant Survanta confer a high degree of resistance to surfactant inhi bition by human albumin in ventilated preterm rabbits, (C) 1999 Academic Pr ess.