Arterial thrombosis: relevance of a model with two levels of severity assessed by histologic, ultrastructural and functional characterization.
BACKGROUND
We previously described a model of laser-induced thrombosis in mesenteric arterioles with superficial and deep levels of injury producing a transient thrombus resolving within 2 min and a larger almost occlusive thrombus, respectively. Both types of lesion were sensitive to platelet GPIIb-IIIa and P2Y(12) inhibition, whereas only deep injuries were sensitive to thrombin blockade.


OBJECTIVE
The aim of the present study was to use histologic methods and electron and intravital microscopy to characterize the lesions and thrombi and to extend our knowledge of the sensitivity of this model to genetic and pharmacologic inhibition.


RESULTS
A superficial injury was found to detach the endothelial cells and expose a collagen III- and IV-rich subendothelium where platelets could adhere. Tissue factor and fibrin were not detected. Deeper penetration of the external elastic lamina occurred in deep injuries, with exposure of collagen I, III and IV. Here the thrombus was composed of platelets exhibiting a decreasing gradient of degranulation from the deepest lesion area to the surface. Fibrin was found close to the most activated platelets. Consistently, glycoprotein VI (GPVI)-collagen and GPIb-von Willebrand factor (VWF) interactions were found to be critical in superficial injuries. After deep lesion, thrombus formation was modestly reduced in GPVI-immunodepleted mice and still strongly inhibited in VWF(-/-) mice. Combined hirudin infusion and GPVI depletion further inhibited thrombosis after deep injury.


CONCLUSIONS
This study confirms the feasibility of inducing arterial thrombosis with distinct levels of severity and establishes the central roles of collagen and VWF in thrombus formation after superficial injury. Collagen, VWF and thrombin all appear to contribute to thrombosis after deep arterial lesion.
Hechler
B
B
UMR S949 INSERM, Université de Strasbourg, Etablissement Français du Sang-Alsace, Strasbourg, France.
Nonne
C
C
Eckly
A
A
Magnenat
S
S
Rinckel
J-Y
JY
Denis
C V
CV
Freund
M
M
Cazenave
J-P
JP
Lanza
F
F
Gachet
C
C
D000818:Animals; D001792:Blood Platelets / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure*; D024042:Collagen Type I / Q000378:metabolism; D024061:Collagen Type III / Q000378:metabolism; D024141:Collagen Type IV / Q000378:metabolism; D004195:Disease Models, Animal; D004730:Endothelium, Vascular / Q000187:drug effects / Q000293:injuries / Q000378:metabolism / Q000648:ultrastructure*; D005240:Feasibility Studies; D005337:Fibrin / Q000378:metabolism; D005343:Fibrinolytic Agents / Q000008:administration & dosage; D006629:Hirudins / Q000008:administration & dosage; D007279:Injections, Subcutaneous; D054020:Lasers, Gas; D008297:Male; D008638:Mesenteric Arteries / Q000187:drug effects / Q000293:injuries / Q000378:metabolism / Q000648:ultrastructure*; D008641:Mesenteric Vascular Occlusion / Q000097:blood / Q000209:etiology / Q000473:pathology* / Q000517:prevention & control; D051379:Mice; D018345:Mice, Knockout; D010973:Platelet Adhesiveness / Q000187:drug effects; D010980:Platelet Membrane Glycoproteins / Q000172:deficiency / Q000378:metabolism; D012720:Severity of Illness Index; D013927:Thrombosis / Q000097:blood / Q000209:etiology / Q000473:pathology* / Q000517:prevention & control; D013997:Time Factors; D014841:von Willebrand Factor / Q000235:genetics / Q000378:metabolism
D024042:Collagen Type I; D024061:Collagen Type III; D024141:Collagen Type IV; D005343:Fibrinolytic Agents; D006629:Hirudins; D010980:Platelet Membrane Glycoproteins; C098341:platelet membrane glycoprotein VI; D014841:von Willebrand Factor; D005337:Fibrin