Regulation of depth and composition of airway surface liquid

Jonathan Widdicombe, S. J. Bastacky, D. X Y Wu, C. Y. Lee

Research output: Contribution to journalArticlepeer-review

67 Scopus citations


The depth and composition of human airway surface liquid (ASL) may depend on secretion from airway glands, ion transport across the surface epithelium, goblet cell discharge, transepithelial gradients in hydrostatic pressure, and surface tension. Published values for the frequency of airway glands and for the secretory rates of individual glands suggest that total gland secretion in human trachea can amount to ~60 μL · cm-2 · h-1. Volume absorption directly measured across cultures of surface epithelium from human trachea is ~5 μL · cm-2 · h-1. These flows should alter the depth of ASL at +10 and -1 μm · min-1. We have looked for changes in ASL depth of this magnitude using low-temperature scanning electron microscopy (LT-SEM) of rapidly frozen specimens of bovine trachea. Stimulation of gland secretion with methacholine led to an initial increase in depth of ~25 μm · min-1 followed by a decline at ~1.5 μm · min-1. Whereas the initial increase in depth was probably due to transient gland secretion, the later decline reflected active absorption of liquid across the surface epithelium. Finally, we present preliminary data showing that LT-SEM can be combined with X-ray microanalysis to determine the elemental composition of ASL.

Original languageEnglish (US)
Pages (from-to)2892-2897
Number of pages6
JournalEuropean Respiratory Journal
Issue number12
StatePublished - Dec 1997


  • Active transepithelial transport
  • Airway surface liquid
  • Low temperature scanning electron microscopy
  • Submucosal glands
  • X-ray microanalysis

ASJC Scopus subject areas

  • Pulmonary and Respiratory Medicine


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