Airway Distension Promotes Leukocyte Recruitment in Rat Tracheal Circulation

Lina H.K. Lim, Elizabeth M. Wagner

Research output: Contribution to journalArticle

Abstract

Mechanical distortion of blood vessels is known to activate endothelial cells. Whether airway distension likewise activates the vascular endothelium within the airway wall is unknown. Using intravital microscopy in the rat trachea, we investigated if airway distention with the application of positive end-expiratory pressure (PEEP) caused leukocyte recruitment to the airway. Tracheal postcapillary venules were visualized and leukocyte kinetics monitored in anesthetized, mechanically ventilated rats (80 breaths/minute, 6 ml/kg V T, 1 cm H2O PEEP). Leukocyte rolling velocity (Vwbc) and the number of adherent cells were not altered with normal ventilation over the course of 2 hours. Ventilation with sustained PEEP (8 cm H2O) for 1 hour reduced Vwbc and increased adhesion, reaching a maximum at 1 hour of PEEP. Intermittent (2x and 5x) 8 cm H2O PEEP also induced a similar reduction in Vwbc, accompanied by an increase in adhesion. However, leukocyte recruitment after airway distension is localized to the airways because increased PEEP did not induce leukocyte recruitment in the mesenteric microcirculation or when PEEP was applied to the lung distal to the site of measurement. Pretreatment with endothelin receptor and selectin inhibitors blocked the effects of distension on leukocyte recruitment, suggesting their involvement in the proinflammatory response.

Original languageEnglish (US)
Pages (from-to)1068-1074
Number of pages7
JournalAmerican journal of respiratory and critical care medicine
Volume168
Issue number9
DOIs
StatePublished - Nov 1 2003

Keywords

  • Airway distension
  • Endothelial activation
  • Intravital microscopy
  • Mechanical stress
  • Positive end-expiratory pressure

ASJC Scopus subject areas

  • Pulmonary and Respiratory Medicine
  • Critical Care and Intensive Care Medicine

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