Pulmonary surfactant phospholipid bilayer (PS)

The pulmonary surfactant phospholipid bilayer is a specialized lipoprotein complex that lines the alveolar surface of the lungs, primarily composed of dipalmitoylphosphatidylcholine (DPPC) and surfactant-associated proteins SP-A, SP-B, SP-C, and SP-D (StatPearls, 2023). Its fundamental biological role is to lower surface tension at the air-liquid interface within the alveoli, which prevents their collapse (atelectasis) at the end of expiration and significantly reduces the work of breathing (NIH, 2022). Beyond mechanical stabilization, the surfactant system is a key component of the lung's innate immunity, helping to opsonize pathogens and modulate inflammatory signaling (PubMed, 2021). Clinical deficiency of this system is the primary cause of Neonatal Respiratory Distress Syndrome (NRDS) in premature infants, while secondary dysfunction is a hallmark of Acute Respiratory Distress Syndrome (ARDS) and meconium aspiration (StatPearls, 2023). Therapeutic strategies target this bilayer through the administration of exogenous surfactants, which rapidly spread across the alveolar surface to restore lung compliance and improve gas exchange (Drugs.com, 2024). Ongoing research also explores the role of surfactant proteins as biomarkers for lung injury and the development of synthetic surfactants to overcome the limitations of animal-derived products.

Other names

Lung surfactantAlveolar surfactantPulmonary surfactant systemSurface-active agent

Exogenous surfactant replacement therapy restores the phospholipid film at the alveolar air-liquid interface, thereby reducing surface tension and preventing alveolar collapse during expiration (StatPearls, 2023).