Adeno-associated virus-mediated vascular endothelial growth factor gene transfer into cardiac myocytes

Vascular endothelial growth factor (VEGF) is an angiogenic growth factor th at stimulates endothelial cell proliferation, increases endothelial permeab ility, and promotes collateral vessel formation. We transferred human VEGF gene into rat cardiac myocytes using adeno-associated virus (AAV) vectors a nd investigated whether VEGF secreted from the transduced cardiac myocytes promoted proliferation of endothelial cells. We produced VEGF-expressing AA V vectors (AAV-VEGF) by the adenovirus-free method. Immunoblotting revealed VEGF protein expression in AAV-VEGF-transduced rat cardiac myocytes. More than 60% of cardiac myocytes were stained positively on immunohistochemical staining using anti-VEGF antibody, Concentration of VEGF in the culture me dium of AAV-VEGF-transduced myocytes was increased in a vector dose-depende nt manner, and VEGF secretion from the transduced myocytes persisted for gr eater than or equal to 14 days. Thymidine incorporation into human vascular endothelial cells was significantly increased by incubation with the condi tioned medium from AAV-VEGF-transduced myocytes. This increased thymidine u ptake was significantly inhibited by anti-VEGF antibody. We demonstrated he re that AAV-mediated VEGF gene transfer into cardiac myocytes induces the s ecretion of functional VEGF.