(Medical Xpress)—Pulmonary surfactants are phospholipoproteins (surface-active lipoprotein complexes) that reduces alveolar surface tension through an air-water hydrophilic/hydrophobic interface. Pulmonary, or lung, surfactants play several vital roles in lung function, including minimizing the energy needed to breathe, increasing pulmonary compliance (the ability of lungs to expand), preventing atelectasis (collapse of the lung at the end of expiration), reversing airway collapse, and regulating alveolar size. However, there are a number of diseases, such as neonatal respiratory distress syndrome (NRDS), congenital surfactant deficiency and pulmonary alveolar proteinosis, which require replacement pulmonary surfactants. In NRDS, for example, while replacement lung surfactants have dramatically reduced premature infant mortality, clinical lung surfactants vary widely in composition, requiring a deeper understanding of the function that each type of surfactant molecular performs. Recently, scientists working with lipid–cholesterol nanodomain complexes at University of California, Santa Barbara and University of Minnesota, Minneapolis demonstrated that small cholesterol fractions reduce surfactant interface viscosity by orders of magnitude while leaving compressibility and collapse unchanged. The researchers conclude that these results suggest the possibility of clinical control over surfactant spreadability.
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