Host lung endothelial and epithelial cells

Host lung endothelial and epithelial cells are the primary structural and functional units of the alveolar-capillary barrier, responsible for efficient gas exchange and protection of the internal environment from inhaled pathogens. The epithelium is composed of Type I pneumocytes, which cover the majority of the alveolar surface for gas diffusion, and Type II pneumocytes, which secrete surfactant and serve as progenitor cells for repair (StatPearls, 2023). The pulmonary endothelium lines the microvasculature, regulating blood flow, nutrient transport, and the recruitment of leukocytes during inflammation (Frontiers in Medicine, 2021). In pathological states such as ARDS or severe viral infections like COVID-19, damage to these cells leads to increased permeability, alveolar flooding, and respiratory failure (Nature Reviews Immunology, 2020). While these cells are not a single molecular target, they express various receptors and enzymes, such as ACE2 and cytokine receptors, which are the focus of therapeutic interventions aimed at reducing inflammation and preventing fibrosis (American Journal of Respiratory and Critical Care Medicine, 2022). Consequently, preserving the health and function of these cell populations is a central goal in treating acute and chronic lung diseases.

Other names

Alveolar-capillary barrierPneumocytes and pulmonary microvascular endothelial cellsLung parenchymaPulmonary epithelial-endothelial unit

Pharmacological agents interact with specific molecular pathways within these cells, such as glucocorticoid receptors to reduce inflammation, tyrosine kinases to inhibit fibrotic signaling, or viral entry receptors like ACE2 to prevent infection, thereby preserving the structural and functional integrity of the lung tissue.