Prolonged leukocyte transit time in the coronary microcirculation
of endotoxemic pigs.
Goddard, Christopher M., Michael F. Allard, James C. Hogg, Michael J.
Herbertson, and Keith R. Walley.
Pulmonary Research Laboratory, St. Paul's Hospital, University of
British Columbia, Vancouver, B.C., Canada V6Z 1Y6.
APStracts 2:0160H, 1995.
We quantified the timing and extent of leukocyte retention by the
coronary microcirculation in a pig model of hyperdynamic sepsis in
three ways. First, the transmyocardial leukocyte gradient was
determined as coronary blood flow (calibrated ultrasonic flow probe)
multiplied by the difference between leukocyte counts in the aorta
and coronary sinus. Measurements were taken at 1 minute intervals for
30 minutes and then 3 minute intervals for 45 minutes in anesthetized
pigs exposed to either endotoxin (50 [mu]g/kg I.V. over 30 minutes)
(n=7) or vehicle (n=7). Second, post mortem morphometric analysis was
used to quantitate the number and location of retained myocardial
leukocytes. Finally, myocardial capillary transit time of leukocytes
was calculated from the above measures. In the endotoxin group 2.1
+/- 0.8 x 109 leukocytes/100g wet weight were retained in the
coronary circulation, primarily in capillaries. This resulted in 111
+/- 37 (p<0.05) times as many leukocytes in the coronary
microcirculation than predicted from the arterial leukocyte
concentration. Myocardial capillary transit time of leukocytes was
prolonged to 39.1 +/- 20.6 s (p<0.05) in the endotoxin group versus
5.0 +/- 1.4 s in the control group. We conclude that, after endotoxin
infusion in a pig model of hyperdynamic sepsis, myocardial leukocyte
transit is slowed leading to the retention of large numbers of
leukocytes in the coronary microcirculation.
Received 6 October 1994; accepted in final form 14 April 1995.
APS Manuscript Number H897-4.
Article publication pending Am. J. Physiol. (Heart Circ. Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 2 May 1995.