369 Modulation of NAP-2-induced Neutrophil (PMN) Activation by Different Surfactant Preparations

Abstract

Background: Lung surfactant, a complex composition of phospholipids, neutral lipids and various apoproteins is essential for lung function. In surfactant deficient neonates treatment was done successfully by endotracheal administration of either natural or artificial surfactant preparations. Alteration of the alveolo-capillary membrane may allow blood compounds, such as proteins and cells to interact with surfactant constituents and vice versa.The aim of our study was to investigate surfactant-related effects on PMN since these cells are major effector cells of the primary immune and inflammatory response, involved in pulmonary failure.Methods: PMN, isolated from citrated blood of 3 healthy volunteers were allowed to interact with different surfactant preparations for a time of 30 minutes. Cell activation, reflected by PMN degranulation was detected by measurements of elastase-activity in the supernatant.Results: While NAP-2-induced elastase release was suppressed about by 70% at concentrations of more than 1.0 mg/ml of natural preparations Survanta® and Curosurf®, the only artificial preparation Exosurf® showed slightly stimulating effects. Alveofact®, in contrast seems to combine both, activating and inhibiting properties, interfering with each other. If unstimulated, PMN were not affected by the surfactant preparations.Conclusion: NAP-2-induced activation of isolated PMN is modulated by surfactant. Clinical implications of preparation related effects have to be elucidated.