Prolonged airway explant culture enables study of health, disease, and viral pathogenesis (preprint)

In vitro models play a major role in studying airway physiology and disease. However, the native lungs complex tissue architecture and non-epithelial cell lineages are not preserved in these models. Ex vivo tissue models could overcome in vitro limitations, but methods for long-term maintenance of ex vivo tissue has not been established. We describe methods to culture human large airway explants, small airway explants, and precision-cut lung slices for at least 14 days. Human airway explants recapitulate genotype-specific electrophysiology, characteristic epithelial, endothelial, stromal and immune cell populations, and model viral infection after 14 days in culture. These methods also maintain mouse, rabbit, and pig tracheal explants. Notably, intact airway tissue can be cryopreserved, thawed, and used to generate explants with recovery of function 14 days post-thaw. These studies highlight the broad applications of airway tissue explants and their use as translational intermediates between in vitro and in vivo studies.

Pharmacokinetic-based failure of a detergent virucidal for SARS-COV-2 nasal infections (preprint)

The nose is the portal for SARS-CoV-2 infection, suggesting the nose as a target for topical antiviral therapies. Because detergents are virucidal, Johnson and Johnson’s Baby Shampoo (J&J) was tested as a topical virucidal agent in SARS-CoV-2 infected subjects. Twice daily irrigation of J&J in hypertonic saline, hypertonic saline alone, or no intervention were compared (n = 24/group). Despite demonstrated safety and robust efficacy in in vitro virucidal assays, J&J irrigations had no impact on viral titers or symptom scores in treated subjects relative to controls. Similar findings were observed administering J&J to infected cultured human airway epithelia using protocols mimicking the clinical trial regimen. Additional studies of cultured human nasal epithelia demonstrated that lack of efficacy reflected pharmacokinetic failure, with the most virucidal J&J detergent components rapidly absorbed from nasal surfaces. This study emphasizes the need to assess the pharmacokinetic characteristics of virucidal agents on airway surfaces to guide clinical trials.