Enhanced endothelialization and microvessel formation in polyester grafts seeded with CD34(+) bone marrow cells

The authors have shown accelerated endothelialization on polyethylene terep hthalate (PET) grafts preclotted with autologous bone marrow. Bone marrow c ells have a subset of early progenitor cells that express the CD34 antigen on their surfaces. A recent in vitro study has shown that CD34(+) cells can differentiate into endothelial cells. The current study was designed to de termine whether CD34(+) progenitor cells would enhance vascular graft heali ng in a canine model. The authors used composite grafts implanted in the do g's descending thoracic aorta (DTA) for 4 weeks. The 8-mm x 12-cm composite grafts had a 4-cm PET graft in the center and 4-cm standard ePTFE grafts a t each end. The entire composite was coated with silicone rubber to make it impervious; thus, the PET segment was shielded from perigraft and pannus i ngrowth. There were 5 study grafts and 5 control grafts. On the day before surgery, 120 mt bone marrow was aspirated, and CD34(+) cells were enriched using an immunomagnetic bead technique, yielding an average of 11.4 +/- 5.3 x 10(6). During surgery, these cells were mixed with venous blood and seed ed onto the PET segment of composite study grafts; the control grafts were treated with venous blood only. Hematoxylin and eosin, immunocytochemical, and AgNO3 staining demonstrated significant increases of surface endothelia lization on the seeded grafts (92% +/- 3.4% vs 26.6% +/- 7.6%; P=.0001) wit h markedly increased microvessels in the neointima, graft wall, and externa l area compared with controls. In dogs, CD34(+) cell seeding enhances vascu lar graft endothelialization; this suggests practical therapeutic applicati ons.