Exogenous pulmonary surfactant: a review focused on adjunctive therapy for SARS CoV-2 including SP-A and SP-D as added clinical marker

Ghati, Amit; Dam, Paulami; Tasdemir, Didar; Kati, Ahmet; Sellami, Hanen; Sezgin, Gulten Can; Ildiz, Nilay; Franco, Octavio L.; Mandal, Amit Kumar; Ocsoy, Ismail

Type I and Type II pneumocytes are two forms of epithelial cells found lining the alveoli in the lungs. Type II pneumocytes exclusively secrete ‘pulmonary surfactants’, a lipo-protein complex made up of 90% lipids (mainly phospholipids) and 10% surfactant proteins (SP-A, SP-B, SP-C, and SP-D). Respiratory diseases like influenza, SARS-CoV and SARS-CoV-2 are reported to preferentially attack type II pneumocytes of the lungs. After viral invasion, consequent viral propagation and destruction of type II pneumocytes causes altered surfactant production, resulting in dyspnea and Acute respiratory distress syndrome (ARDS) in COVID-19 patients. Exogenous animal-derived or synthetic pulmonary surfactant therapy has already shown immense success in the treatment of neonatal respiratory distress syndrome (RDS) and has the potential to contribute efficiently to repairing damaged alveoli and preventing SARS-CoV-2-associated respiratory failure. Furthermore, the early detection of surfactant collectins (SP-A and SP-D) in the circulatory system can be a significant clinical marker for disease prognosis in the near future.