Bacterial killing by neutrophils in hypertonic environments.
The effects of hypertonic sodium chloride and urea solutions on the phagocytosis and killing of Escherichia coli by neutrophils were examined. Neutrophil function was progressively inhibited by increasing osmolarity, with sodium chloride more inhibitory than urea. However, neutrophils killed at 25% of normal rates in 500 mosmol/L NaCl, and in 300 mosmol/L NaCl with 800 mosmol/L urea. These concentrations would rarely be exceeded in the human urinary tract. Inhibition of neutrophil superoxide production and degranulation was similar to that observed with phagocytosis and killing. Neutrophils also phagocytosed and killed E. coli in isotonic and hypertonic urine, but no improvement in function attributable to the uptake of urinary osmoprotectants was evident. It is concluded that physiologic levels of sodium chloride and urea will slow, but not prevent, neutrophil activity at a hypertonic site of infection.
Hampton
M B
MB
Department of Pathology, Christchurch School of Medicine, New Zealand.
Chambers
S T
ST
Vissers
M C
MC
Winterbourn
C C
CC
D015550:Cell Degranulation / Q000187:drug effects; D004926:Escherichia coli / Q000276:immunology*; D006982:Hypertonic Solutions; D009504:Neutrophils / Q000187:drug effects / Q000502:physiology*; D009994:Osmolar Concentration; D010587:Phagocytosis / Q000187:drug effects*; D012462:Saline Solution, Hypertonic / Q000494:pharmacology*; D013481:Superoxides / Q000378:metabolism; D014508:Urea / Q000494:pharmacology*; D014556:Urine / Q000502:physiology
D006982:Hypertonic Solutions; D012462:Saline Solution, Hypertonic; D013481:Superoxides; D014508:Urea