Pulmonary epithelial barrier integrity

Pulmonary epithelial barrier integrity is a critical physiological state representing the structural and functional robustness of the cellular layer separating the airspaces from the underlying lung interstitium and vasculature. This barrier is primarily maintained by the apical junctional complex, consisting of tight junctions (e.g., claudins, occludin) and adherens junctions (e.g., E-cadherin), which strictly regulate paracellular permeability and maintain alveolar fluid balance (PMID: 25243156). In pathological conditions such as Acute Respiratory Distress Syndrome (ARDS), sepsis, or severe viral pneumonia, inflammatory mediators trigger the disassembly of these junctions, leading to protein-rich fluid exudation into the alveoli and subsequent respiratory failure (PMID: 30103438). While barrier integrity itself is a complex biological phenomenon rather than a single druggable protein, it serves as a primary therapeutic endpoint for interventions aimed at junctional stabilization, such as Rho-kinase inhibitors or growth factors like Palifermin (PMID: 29141317). Monitoring this integrity in clinical settings often involves biomarkers like soluble Receptor for Advanced Glycation End-products (sRAGE), which reflects type I alveolar cell injury and barrier compromise (PMID: 22459411).

Other names

Alveolar-capillary barrier integrityLung epithelial barrier functionAirway epithelial barrierAlveolar epithelial permeability

Stabilization of apical junctional complexes (tight and adherens junctions), promotion of alveolar fluid clearance via ion channel regulation, and inhibition of pro-inflammatory signaling pathways that induce paracellular leakage.