Improved Angiogenic Response in Pig Heart Following Ischaemic Injury Using Human Skeletal Myoblast Simultaneously Expressing VEGF165 and Angiopoietin-1

OBJECTIVE: To achieve angiogenic interaction between VEGF(165) and angiopoietin-1 (Ang-1) using a novel adenoviral bicistronic vector (Ad-Bic) encoding the two factors and delivered ex vivo using sex-mismatched human skeletal myoblasts. METHODS AND RESULTS: A myocardial infarction model was developed in 29 female pigs; randomised into four groups: DMEM (group-1, n=6); Adenovirus null (Ad-null) vector-myoblast (group-2, n=5); Ad-Ang-1 myoblast (group 3, n=7) and Ad-Bic-myoblast (group-4, n=11). Three weeks later, 5 ml DMEM without myoblasts or containing 3 x 10(8) myoblasts carrying lac-z gene and transduced with Ad-null, Ad-Ang-1 or Ad-Bic were injected intra-myocardially in and around the infarct. 2D-echocardiography and fluorescent microsphere studies 6- and 12-weeks post-treatment revealed significantly improved cardiac performance and regional blood flow in groups 3 and 4. Histological studies and Y-chromosome analysis revealed extensive survival of lac-z positive myoblasts staining positive for human proteins in the pig heart. ELISA, immunostaining and RT-PCR revealed that Ad-Bic transduced myoblasts concomitantly but transiently expressed hVEGF(165) and Ang-1 both in vitro and in vivo. Double fluorescent immunostaining of the tissue sections for vWFactor-III and smooth muscle actin showed significantly higher vascular density of mature blood vessels per low power microscopic field in groups 3 and 4 at 6- and 12-weeks. CONCLUSION: Our combined approach led to enhanced angiogenesis with a greater percentage of functionally mature blood vessels in a porcine heart.