Tracheobronchial Stem Cell Attrition After Injury

A recent STEM CELLS Translational Medicine article from researchers led by Susan D. Reynolds (Nationwide Children's Hospital, Columbus, OH, USA) reports on the biological aging of tracheobronchial tissue-specific stem cells (TSCs) and their trophic unit, the pseudostratified conducting airway epithelium. Ghosh et al. describe how each injury activates a subset of TSCs, which proliferate and undergo terminal differentiation; thus, each injury cycle depletes the TSC pool, and multiple injuries lead to compromised epithelial regeneration. Over time, they underscore that biological age will exceed chronological age, which increases the risk of chronic lung diseases.