Can autologous vascular endothelial cell seeding increase the patency rate of small-diameter No-React-treated bovine internal mammary arteries? An in vivo study in juvenile sheep.

Background: This study was performed to evaluate the possibility of seeding No-React-treated bovine small-diameter internal mammary arteries (SIMAs) and to record any improvement in patency rate.

Material/methods: During the in vitro study, 12 seeded SIMAs were divided into two groups; group I (n=6) was endothelial cell (EC) seeded and group II (n=6) EC seeded after pre-coating with fibrin glue to evaluate the binding capacity. During the in vivo part of the study, eight juvenile sheep received either a seeded or a non-seeded SIMA. In the seeded group (n=3), a piece of jugular vein was harvested to culture autologous ECs. SIMA grafts were coated and seeded in a special bioreactor. In the control group (n=5), non-seeded SIMA grafts were implanted. No anti-coagulation was administered. Explantation was performed at three and six months post-implantation. Grafts were evaluated by gross examination, histology, and immunohistochemistry.

Results: By inserting two million ECs in the in vitro study, the seeding density in group I was 1.29+/-0.09 x 10(5) cells/cm(2) and 2.27+/-0.17 x 10(5) cells/cm(2) in group II (p<0.003). In the in vivo study the mean EC density of the implanted seeded grafts was 2.35+/-0.04 x 10(5) cells/cm(2). At explantation, the seeded grafts showed less inflammatory reaction and a higher patency rate compared with the non-seeded grafts. Histology showed a monolayer of ECs on the inner surface of seeded SIMAs at follow-up.

Conclusions: Seeding of No-React-treated SIMA arterial grafts with autologous ECs increases the patency rate.