Interaction between airway edema and lung inflation on responsiveness of individual airways in vivo

Research output: Contribution to journalArticlepeer-review

Abstract

Inflammatory changes and airway wall thickening are suggested to cause increased airway responsiveness in patients with asthma. In five sheep, the dose-response relationships of individual airways were measured at different lung volumes to methacholine (MCh) before and after wall thickening caused by the inflammatory mediator bradykinin via the bronchial artery. At 4 cmH2O transpulmonary pressure (Ptp), 5 μg/ml MCh constricted the airways to a maximum of 18 ± 3%. At 30 cmH2O Ptp, MCh resulted in less constriction (to 31 ± 5%). Bradykinin increased airway wall area at 4 and 30 cmH2O Ptp (159 ± 6 and 152 ± 4%, respectively; P < 0.0001). At 4 cmH2O Ptp, bradykinin decreased airway luminal area (13 ± 2%; P < 0.01), and the dose-response curve was significantly lower (P = 0.02). At 30 cmH2O, postbradykinin, the maximal airway narrowing was not significantly different (26 ± 5%; P = 0.76). Bradykinin produced substantial airway wall thickening and slight potentiation of the MCh-induced airway constriction at low lung volume. At high lung volume, bradykinin increased wall thickness but had no effect on the MCh-induced airway constriction. We conclude that inflammatory fluid leakage in the airways cannot be a primary cause of airway hyperresponsiveness.

Original languageEnglish (US)
Pages (from-to)366-370
Number of pages5
JournalJournal of applied physiology
Volume83
Issue number2
DOIs
StatePublished - Aug 1997

Keywords

  • Bradykinin
  • High-resolution computed tomography
  • Hyperreactivity
  • Hyperresponsiveness
  • Methacholine

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)

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