Oxidized low-density lipoproteins and microvascular responses to ischemia-reperfusion.
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 nonischemic mesentery of either normotensive Wistar-Kyoto or spontaneously hypertensive 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 versus normotensive animals.
Liao
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Department of Physiology and Biophysics, Louisiana State University Medical Center, Shreveport 71130-3932, USA.
Harris
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Granger
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D000818:Animals; D001808:Blood Vessels / Q000503:physiopathology; D002199:Capillary Permeability; D002448:Cell Adhesion; D004730:Endothelium, Vascular / Q000503:physiopathology; D005260:Female; D006801:Humans; D006973:Hypertension / Q000503:physiopathology; D007511:Ischemia / Q000503:physiopathology*; D007962:Leukocytes / Q000502:physiology; D008077:Lipoproteins, LDL / Q000502:physiology*; D008297:Male; D008407:Mast Cells / Q000502:physiology; D008833:Microcirculation; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D017207:Rats, Sprague-Dawley; D015424:Reperfusion; D013152:Splanchnic Circulation
D008077:Lipoproteins, LDL; C099252:oxidized low density lipoprotein