Endograft technology: a delivery vehicle for intravascular gene therapy.
OBJECTIVE
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.


METHODS
SMCs harvested from dog jugular vein were retrovirally transduced to introduce genes for tissue plasminogen activator (t-PA) and beta-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 beta-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 10(5) cells per 24 hours and 1.4 +/- 0.1 IU/mL per 10(5) cells per 24 hours) than in control endografts (0.5 +/- 0.03 ng/mL per 10(5) cells per 24 hours and 0.07 +/- 0.00 IU/mL per 10(5) cells per 24 hours; P <.001). No graft stenosis was observed.


CONCLUSIONS
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.
Eton
Darwin
D
Department of Surgery, University of Miami School of Medicine, Miami, Fla, USA.
Yu
Hong
H
Wang
Yingcai
Y
Raines
Jeffrey
J
Striker
Gary
G
Livingstone
Alan
A
D000818:Animals; D001012:Aorta, Abdominal / Q000601:surgery; D019917:Blood Vessel Prosthesis Implantation; D004285:Dogs; D015316:Genetic Therapy / Q000379:methods*; D005822:Genetic Vectors; D007601:Jugular Veins; D009131:Muscle, Smooth, Vascular / Q000166:cytology*; D011093:Polyethylene Terephthalates; D012190:Retroviridae; D015607:Stents; D013997:Time Factors; D010959:Tissue Plasminogen Activator / Q000235:genetics; D014161:Transduction, Genetic; D001616:beta-Galactosidase / Q000235:genetics
D011093:Polyethylene Terephthalates; D001616:beta-Galactosidase; D010959:Tissue Plasminogen Activator