Organoid technology demonstrates effects of potential drugs for COVID‐19 on the lung regeneration

To the Editor, Upon entry into the lungs, SARS‐CoV‐2 uses the angiotensin‐converting enzyme 2 (ACE2) receptor to facilitate viral entry into the epithelial cells that cover the airways and the alveolar gas‐exchanging space, leading to extensive epithelial injury, which contributes to local inflammatory storm and a series of respiratory syndromes. 1 A number of drugs, based on their modes of action, have been suggested as therapeutic candidates for COVID‐19, and some of them are being evaluated in accelerated clinical trials. 1 The antimalarial drugs chloroquine and hydroxychloroquine and the anti‐influenza drug umifenovir inhibit endocytosis of the virus. Insufficient epithelial repair could lead to progression of lung fibrosis, which is thought to occur in COVID‐19 patients. 5 Stem/progenitor cell–derived three‐dimensional organoids serve not only as a model for evaluating stem/progenitor cell function in vitro, but also as a powerful platform for drug screening and safety assays. The clinical efficacy of these drugs as established by current trials is still controversial and needs to be further optimized in terms of dosage, timing of administration and administration routes. 10 Considering that primary human lung progenitor cells are usually hard to access, mouse organoid systems used in this study lay the foundation for further evaluation of existing and experimental drugs, in order to achieve better prognosis against SARS‐CoV‐2 infections.