title: Exudative neutrophils show impaired pH regulation compared with circulating neutrophils.
abstract: OBJECTIVE
  To investigate the effects of neutrophil (PMN) transmigration into inflammatory sites on cytosolic pH (pHi) regulation.
  
  
  METHODS
  Exudative PMNs were obtained by bronchoalveolar lavage from rats sustaining endotoxin-induced lung injury. Circulating PMNs were purified with density-gradient centrifugation. Cytosolic pH was measured with single-cell fluorescence imaging using the pH-sensitive dye biscarboxyethyl-carboxyfluorescein.
  
  
  RESULTS
  Exudative PMNs showed impaired pHi recovery from an induced acid load compared with circulating PMNs. Under conditions of extracellular acidosis, exudative PMNs showed impaired pHi homeostasis and produced decreased superoxide compared with circulating cells. Inhibition of the sodium-proton exchanger attenuated the differences in pHi recovery, suggesting a mechanism underlying the pHi regulatory dysfunction. All cells had comparable adenosine triphosphate levels and superoxide production at physiologic extracellular pH.
  
  
  CONCLUSIONS
  Impaired pHi regulation of exudative cells may mediate cellular dysfunction and impaired resolution of infection at inflammatory sites.
authors.affiliation: Department of Surgery, Toronto Hospital, University of Toronto, Ontario.
authors.forename: D J
authors.initials: DJ
authors.lastname: Hackam
authors.forename: S
authors.initials: S
authors.lastname: Grinstein
authors.forename: A
authors.initials: A
authors.lastname: Nathens
authors.forename: W G
authors.initials: WG
authors.lastname: Watson
authors.forename: J C
authors.initials: JC
authors.lastname: Marshall
authors.forename: O D
authors.initials: OD
authors.lastname: Rotstein
mesh_terms: D000138:Acidosis / Q000378:metabolism; D000818:Animals; D001992:Bronchoalveolar Lavage Fluid / Q000166:cytology*; D005122:Exudates and Transudates / Q000166:cytology*; D006706:Homeostasis; D006863:Hydrogen-Ion Concentration; D009504:Neutrophils / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley