Vascular endothelial growth factor induces brain erythropoietin expression?

To investigate whether the formation of vascular endothelialgrowth factor (VEGF) influences erythropoietin(EPO) expression in physiological conditions, weinjected into the left lateral cerebral ventricle of theMongolian gerbil an adeno-associated virus (AAV) vectorcapable of expressing the 165-amino-acid isoformof VEGF (VEGF165). Twelve and 18 days after AAV vectorinjection, the experimental animals were sacrificedand expression of EPO was evaluated through immunohistochemicalanalysis of both the hippocampusand the frontal cortex.We observed that VEGF165 induces EPO expression inthe hippocampal pyramidal layers and in the frontalcortex of the gerbil, particularly after the 18th day followingtreatment with the vector, which suggests thatVEGF165 could act as a hypoxic-like signal for EPO production.This finding could help to clarify the functionalrole of EPO and the molecular mechanisms by whichVEGF might mediate its effects in the brain.