Pulmonary surfactant (PS) (PS)

Pulmonary surfactant is a complex lipoprotein mixture, primarily composed of phospholipids (notably dipalmitoylphosphatidylcholine) and specific surfactant proteins (SP-A, SP-B, SP-C, and SP-D), that forms a thin film at the air-liquid interface of the alveoli [1.4.1, 1.4.4]. Its primary biological function is to reduce surface tension within the lungs, which prevents alveolar collapse (atelectasis) at the end of expiration and significantly decreases the work of breathing [1.1.2, 1.4.4]. A deficiency of this substance is the hallmark of Neonatal Respiratory Distress Syndrome (NRDS) in premature infants, while its inactivation by plasma proteins or inflammatory mediators contributes to the pathophysiology of Acute Respiratory Distress Syndrome (ARDS) in adults [1.2.2, 1.3.3, 1.6.4]. Therapeutic intervention involves the administration of exogenous surfactant preparations, which can be animal-derived (e.g., poractant alfa, beractant) or synthetic (e.g., lucinactant), delivered directly into the airways to restore interfacial stability [1.1.2, 1.1.5]. Beyond its mechanical roles, the surfactant film also participates in innate immunity, with its hydrophilic proteins (SP-A and SP-D) acting as collectins that recognize and facilitate the clearance of inhaled pathogens [1.3.1, 1.4.4].

Other names

Lung surfactantAlveolar surfactantSurface-active materialPulmonary surfactant film

Exogenous replacement of endogenous surfactant to restore interfacial stability, reduce alveolar surface tension, and improve lung compliance [1.1.2, 1.6.1].