Mouse cremaster venules are predisposed to light/dye-induced thrombosis independent of wall shear rate, CD18, ICAM-1, or P-selectin.
OBJECTIVE
Microvascular adhesion of platelets to endothelium occurs in response to various inflammatory stimuli, and in venules is often accompanied by adherent leukocytes. In a light/dye injury model, platelet adhesion and thrombi occur preferentially in venules, though the reasons for this predisposition are unknown. The authors sought to determine whether lower wall shear rates or leukocyte-endothelial interactions accounted for preferential platelet thrombi formation in venules relative to arterioles.


METHODS
A light/dye injury model of microvascular thrombosis was used in the mouse cremaster microcirculation.


RESULTS
In wild-type mice (n = 17), the time to form microvascular platelet aggregates was delayed in arterioles by 3.1-fold relative to venules (p <.0001). However, arterioles with spontaneously low wall shear rates, as well as arterioles manipulated to reduce wall shear rate to venous levels, still had delayed thrombosis as compared to venules. Similarly, in animals deficient in CD18, P-selectin, or ICAM-1, the time to form platelet thrombi in arterioles was >3.0-fold higher than in venules.


CONCLUSIONS
Mouse cremaster venules are predisposed to light/dye-induced microvascular thrombosis. The data suggest that functional differences between arteriolar and venular endothelial cells (independent of wall shear rate and of CD18, P-selectin, and ICAM-1) account for the venular predisposition to thrombosis.
Department of Medicine, Baylor College of Medicine, Houston, Texas 77030, USA. rrumbaut@bcm.tmc.edu
Rolando E
RE
Rumbaut
Jaspreet Kaur
JK
Randhawa
C Wayne
CW
Smith
Alan R
AR
Burns
D000818:Animals; D018821:CD18 Antigens / Q000502:physiology; D015815:Cell Adhesion Molecules / Q000502:physiology*; D002450:Cell Communication / Q000502:physiology; D004396:Coloring Agents; D004195:Disease Models, Animal; D004730:Endothelium, Vascular / Q000166:cytology / Q000502:physiology; D018799:Intercellular Adhesion Molecule-1 / Q000502:physiology; D007962:Leukocytes / Q000166:cytology / Q000502:physiology; D008027:Light; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018482:Muscle, Skeletal / Q000098:blood supply*; D019007:P-Selectin / Q000502:physiology; D013314:Stress, Mechanical; D013927:Thrombosis / Q000209:etiology*; D014699:Venules / Q000473:pathology / Q000503:physiopathology*
D018821:CD18 Antigens; D015815:Cell Adhesion Molecules; D004396:Coloring Agents; D019007:P-Selectin; D018799:Intercellular Adhesion Molecule-1