Thrombospondin 1 requires von Willebrand factor to modulate arterial thrombosis in mice

Abstract

Thrombospondin 1 (TSP1) has been suggested as a counter receptor to platelet glycoprotein Ibα that supports initial platelet adhesion in absence of von Willebrand factor (VWF). Conversely, several other studies have shown that TSP1 interacts with VWF and may play a mechanistic role in modulating thrombosis. However, the in vivo evidence to support this mechanism remains unclear. Using intravital microscopy, in a 10% FeCl3-induced thrombosis model, we report similar platelet adhesion in Tsp1-/-/Vwf-/- mice compared with littermate Vwf-/- mice, suggesting that TSP1 does not mediate initial platelet adhesion in the absence of VWF. Tsp1-/- mice exhibited prolonged occlusion time and a significant decrease in the rate of thrombus growth (P