A platelet tetraspanin superfamily member, CD151, is required for regulation of thrombus growth and stability in vivo

Background: This study was designed to determine the role of CD151 in platelet thrombus formation in vivo and define the contribution of platelet vs. endothelial CD151 in regulating platelet thrombus formation in vivo. Methods and Results: Using intravital microscopy and ferric chloride (FeCl3) injury of mesenteric arterioles, we found that thrombi formed in CD151+/- and CD151-/- mice were smaller and less stable, than those formed in CD151+/+ mice, with a tendency for embolization. Similarly, in Folt's FeCl3-induced carotid injury model, both CD151+/- and CD151-/- mice showed more prolonged times to 95% vessel occlusion than CD151+/+ mice. In addition, laser-induced injury of cremaster muscle arterioles showed that thrombi formed in CD151+/- and CD151-/- mice were smaller and less stable than those formed in CD151+/+ mice. Following platelet depletion/reconstitution with ex vivo-labeled donor platelets, platelet-depleted CD151+/+ mice that received reconstitution with CD151-/- platelets had smaller thrombi that were unstable and embolized. In contrast, platelet-depleted CD151-/- mice that received reconstitution with CD151+/+ platelets had normal thrombi that were stable. Conclusions: These data provide evidence that platelet CD151 is required for regulating thrombus formation in vivo.