A possible role for l-selectin in the release of polymorphonuclear
leukocytes (pmn) from the bone marrow.
Eeden, Stephan F Van, Robert Miyagashima, Lawrence Haley, and James C.
Hogg.
Institute: Pulmonary Research Laboratory, Departments of Pathology
and Cardiothoracic Surgery, University of British Columbia, St.
Paul's Hospital, Vancouver, B.C. Canada
APStracts 3:0476H, 1996.
Previous studies from our laboratory have shown that the expression of
L-selectin on polymorphonuclear leukocytes (PMN) is higher in the
bone marrow than in peripheral blood. The present study was designed
to determine the location of this L-selectin loss as the PMN pass
from the hematopoietic tissue into venous sinusoids of the bone
marrow. Bone marrow and peripheral blood samples were collected at
the beginning, during and just after 5 normothermic cardiopulmonary
bypass procedures where there was active marrow release and compared
to 5 hypothermic procedures where marrow release was suppressed by
lowering body temperature to 270C. L-selectin expression was measured
on PMN in the hematopoietic tissue and venous sinusoids in the bone
marrow using quantitative histology and immunocytochemistry. At
baseline there was more L-selectin on PMN in the bone marrow
sinusoids than in the hematopoietic tissue (24.7+/-3.5% vs 10.3+/
-2.5%, p<0.004). Bone marrow release during normothermic CPB was
associated with a rise in peripheral blood band cells (0.18+/-0.7 vs
2.98+/-0.56 x 109/L, p<0.01), and a further reduction of L
-selectin expression on PMN in the sinusoids (p<0.03). Hypothermia
(270C) prevented both the rise in peripheral blood band cells and the
reduction in L-selectin on PMN in the sinusoids. In vitro studies
showed that lowering the temperature had a similar effect on shedding
of L-selectin from PMN. We conclude that PMN shed L-selectin as they
move from the hematopoietic compartment into the venous sinusoids of
the bone marrow and postulate that this could control the release of
PMN from the marrow.
Received 24 January 1996; accepted in final form 2 October 1996.
APS Manuscript Number H71-6.
Article publication pending Am. J. Physiol. (Heart Circ. Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 31 December 1996