Oxidized low density lipoproteins and the microvascular responses
to ischemia-reperfusion.
Liao, Lianxi, Norman R. Harris, and D. Neil Granger.
Department of Physiology and Biophysics, Louisiana State University
Medical Center, Shreveport, Louisiana 71130
APStracts 3:0266H, 1996.
The objective of this study was to determine whether ischemia and
reperfusion (I/R) and/or chronic arterial hypertension potentiates
the leukocyte-endothelial cell adhesion (LECA) and microvascular
dysfunction elicited by oxidized low density lipoproteins (ox-LDL).
Mast cell degranulation, leukocyte adherence and emigration, and
albumin leakage were monitored in postcapillary venules of rat
mesentery. Intra-arterial infusion of copper oxidized LDL (Cu-LDL),
at a concentration that does not directly affect the
microvasculature, significantly enhanced the I/R-induced recruitment
of adherent and emigrated leukocytes but does not affect the
increased albumin leakage and mast cell degranulation responses
normally observed after I/R. Infusion of a higher concentration of
Cu-LDL in non-ischemic mesentery of either normotensive (WKY) or
spontaneously hypertensive (SHR) rats elicited significant yet
similar increases in LECA, mast cell degranulation and albumin
leakage. These findings indicate that 1) ox-LDL act synergistically
with I/R to promote leukocyte recruitment in postcapillary venules,
but without an accompanying exacerbation of albumin leakage, and 2)
ox-LDL do not elicit a more intense inflammatory response in the
microvasculature of hypertensive vs normotensive animals.
Received 5 March 1996; accepted in final form 24 May 1996.
APS Manuscript Number H217-6.
Article publication pending Am. J. Physiol. (Heart Circ. Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 4 July 96