ELN and respiratory failure: Adult MUC5B-deficient mice displayed bronchial hyperplasia and metaplasia, interstitial thickening, alveolar collapse, immune cell infiltrates, fragmented and disorganized elastin fibers, and collagen deposits that were, for approximately one-fifth of the mice, associated with altered pulmonary function leading to respiratory failure demonstrating that the mouse MUC5B is essential for maintaining normal lung function (Valque et al., 2019).