CD34 and Stroke: Furthermore, the observation that juvenile EPC-infusions into stroke-prone spTg25+ female rat recipients at 3 m and 4 m of age can delay stroke onset without need for anti-hypertensive therapy suggests a central ‘master-switch’ role for cd45- [cd34+/kdr+]EPCs in stroke pathogenesis via the putative attenuation of microvascular paucity leading to chronic low flow ischemia observed in the spTg25+ female rat model [8].