Abstract 5304: Ectonucleoside Triphosphate Diphosphohydrolase-1 (ENTDP-1/CD39) Over-Expression Delays in vivo Carotid Arterial Thrombosis in Mice

Background: Vascular injury results in release adenosine diphosphate (ADP), activating platelets leading to further release of ADP from platelet granules. ADP release results in platelet aggregation and cross-linking. Ectonucleoside Triphosphate Diphosphohydrolase-1 (ENTDP-1/ CD39), an endothelial cell-expressed diphosphonucleotidase, rapidly converts ATP and ADP to AMP which is further degraded by ecto-5′-nucleotidase (CD73) to adenosine, an anti-thrombotic, vasodilatory and cardioprotective compound. We hypothesized that transgenic CD39 over-expression would increase the time to thrombosis in an in vivo ferric chloride-induced carotid artery thrombosis model. Methods: Mice, 8 –12 week old human CD39 overexpressing (hCD39-OE) and wildtype littermates, were anesthetized using 55 mg/kg ketamine and 15 mg/kg xylazine, intubated, and ventilated with room air using a mouse respirator (Harvard Apparatus). A midline incision was made and the left carotid artery was exposed. Baseline carotid blood flow was obtained using a Doppler flow probe (Model 0.5 VB, Transonics Systems). Thrombosis was induced by placing filter paper saturated with 10% FeCl3 on the carotid artery for 3 minutes. Carotid blood flow was monitored continuously and time to cessation of flow analyzed. Results: In response to FeCl3 induced injury, wild-type mice demonstrated a consistent time to occlusion of 8±1 minute. In contrast, in animals overexpressing hCD39, the time to occlusion following FeCl3 induced injury was profoundly increased to 60±2 minutes (>7-fold). (Figure ). Conclusion: CD39 over-expression significantly delays the time to arterial thrombosis.