Purpose: The purpose of this study was to determine whether vascular smooth muscle cells (SMCs) suffused into a bilayered stent graft retain and express a retrovirally transduced gene for 7 months in vivo. Method: SMCs harvested from dog jugular vein were retrovirally transduced to introduce genes for tissue plasminogen activator (t-PA) and β-galactosidase. These cells were then suffused into a novel dual-layered Dacron graft and cultured for 36 to 48 hours. The grafts were mounted on a Palmaz stent and balloon-expanded in the infrarenal aorta of the SMC donor dogs (n = 6). Grafts were recovered at 1, 2, 3, 4, 5, and 7 months. A control endograft suffused with SMCs transduced with only the β-galactosidase gene was placed in the dogs with grafts recovered at 2, 3, and 4 months. t-PA antigen concentration and expression were analyzed with an enzyme-linked immunosorbent assay. Results: Retained engineered SMCs (blue nuclei) were identified in the explanted grafts, neointima, and underlying aorta with X-gal staining. The t-PA antigen concentration and t-PA activity from the SMCs recovered from the grafts remained elevated for the duration of the experiment (7 months) at levels significantly higher (3.7 ± 0.2 ng/mL per 105 cells per 24 hours and 1.4 ± 0.1 IU/mL per 105 cells per 24 hours) than in control endografts (0.5 ± 0.03 ng/mL per 105 cells per 24 hours and 0.07 ± 0.00 IU/mL per 105 cells per 24 hours; P < .001). No graft stenosis was observed. Conclusion: Retrovirally engineered vascular SMCs survived the implantation trauma, repopulated each graft, migrated into the underlying aorta, and expressed the transduced genes for the 7-month duration of the experiment. This bilayered Dacron endograft model provides a platform to study direct intravascular gene therapy.
ASJC Scopus subject areas
- Cardiology and Cardiovascular Medicine