The invention provides a vector which is capable of the expression of a vascular endothelial growth factor wherein the vector comprises a modified PCMV promoter. The invention further provides use of a vector which is capable of and expressing a vascular endothelial growth factor (VEGF) for the regulation of endothelial function, angiogenesis and arteriogenesis. The invention further comprises use of a vector which is capable of the expression of a vascular endothelial growth factor (VEGF) for the prophylactic treatment of arterial diseases and/or bone marrow diseases and/or neural diseases.