Protein and angiogenic dose-response expression of phVEGF-A(165) gene in rat myocardium.

Therapeutic myocardial angiogenesis by means of transient overexpression of angiogenic growth factors is a potential treatment modality for severe ischemic heart disease. This study was undertaken in the rat to examine effects of phVEGF-A(165) myocardial transfection in terms of dose-response as regards the number of hVEGF-A expressing cells on one hand and on the other angiogenesis. Non-surgical echocardiography-guided intramyocardial injection of phVEGF-A(165) was done into normoxic or hypoxic (10% O(2)) rats. Cardiomyocytes expressing VEGF-A protein, capillary morphology and density were determined after 5 days. VEGF protein expression was seen in rat cardiomyocytes located around the tip of the injection scar and increased dose-dependently (p<0.05). Microvessel density also increased dose-dependently with phVEGF(165) (p<0.05) and with hypoxia (p<0.05). No vascular tumours were observed. In conclusion, direct intramyocardial injection of phVEGF-A(165) in the rat results in a dose-dependent increase both in transfected hVEGF-A protein producing cells and in angiogenesis.