Abstract 19: CD39 Expression on Circulating Blood Components Prolongs the Time to Ferric Chloride--Induced Carotid Artery Thrombosis in Mice

Objective: To determine the effect of increased CD39 expression on circulating blood components on in vivo arterial thrombosis in mice. Approach and Results: We have previously demonstrated that increased global expression of hCD39 conveys an anti-thrombotic phenotype in mice suggesting a pivotal role for CD39 in modulating the balance between a pro-thrombotic and anti-thrombotic milieu. We hypothesized the expression of CD39 on circulating blood components can regulate occlusive thrombus formation. Bone marrow transplantations were performed (WT to WT; WT to hCD39-Tg; hCD39-Tg to hCD39-Tg; hCD39-Tg to WT) to determine the contribution of CD39 expressed on circulating blood cells and platelets on occlusive arterial thrombus formation in mice. Complete blood counts and fluorescence-activated cell sorting (FACS) analyses were performed on whole blood obtained from mice 60 days after transplantation of bone marrow. No significant differences in the circulating levels of white blood cells, red blood cells, and platelets were observed between the groups. FACS analysis confirmed that the circulating blood components were reconstituted from the transplanted bone marrow. Carotid artery thrombosis was induced by ferric chloride (FeCl 3 ) application and the time to thrombotic occlusion (blood flow of 0 ml/min) was measured. The operator was blinded to the animal genotype and treatment during all experiments. Transplantation of CD39-Tg bone marrow into WT mice resulted in a marked resistance to thrombosis (CD39-Tg to WT: 315.7.00 ± 54.6 min; WT to WT: 7.58 ± 0.89 min; P P Conclusion: Increased expression of CD39 on circulating bone-marrow-derived blood components markedly prolongs the time to carotid artery occlusion following ferric-chloride-induced injury in mice.