Journal of Applied Physiology, Vol 59, Issue 6 1796-1801, Copyright © 1985 by American Physiological Society
Pulmonary neutrophil kinetics in sheep: effects of altered hemodynamics
J. A. Cooper, R. Bizios and A. B. Malik
We investigated the effect of elevated left atrial pressure and reduced
cardiac output on pulmonary neutrophil kinetics in the sheep. Sheep
neutrophils were isolated, labeled with 111In-oxine, and reinfused.
Erythrocytes were labeled with [99mTc]pertechnetate. A gamma camera
measured the lung activities of the labeled neutrophils and erythrocytes.
The results indicated that 38.5% of the total injected neutrophils
marginated in the lung. Pulmonary hemodynamics were altered by inflating a
left atrial balloon three times in each sheep for 15-30 min to achieve 5-
to 25-mmHg increments in pulmonary arterial wedge pressure. At least a
30-min recovery period was allowed between inflations. After each left
atrial balloon inflation, neutrophil uptake remained unchanged from base
line, despite decreased mean cardiac output to 0.67 +/- 0.24 (+/- SD) 1/min
and increased pulmonary blood volume. The absence of pulmonary neutrophil
uptake was confirmed by arterial-venous measurements. Increased pulmonary
blood volume had little effect on lung neutrophil uptake, suggesting that
most of the pulmonary neutrophils are marginated. We conclude that the
lungs have a large marginated neutrophil pool compared with the circulating
pool and that reduced cardiac output and elevated left atrial pressure have
no effect on pulmonary neutrophil kinetics in the sheep.
