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

The authors have shown accelerated endothelialization on polyethylene terephthalate (PET) grafts preclotted with autologous bone marrow. Bone marrow cells 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 determine whether CD34 + progenitor cells would enhance vascular graft healing in a canine model. The authors used composite grafts implanted in the dog9s descending thoracic aorta (DTA) for 4 weeks. The 8-mm × 12-cm composite grafts had a 4-cm PET graft in the center and 4-cm standard ePTFE grafts at each end. The entire composite was coated with silicone rubber to make it impervious; thus, the PET segment was shielded from perigraft and pannus ingrowth. There were 5 study grafts and 5 control grafts. On the day before surgery, 120 mL bone marrow was aspirated, and CD34 + cells were enriched using an immunomagnetic bead technique, yielding an average of 11.4 ± 5.3 × 10 6 . During surgery, these cells were mixed with venous blood and seeded onto the PET segment of composite study grafts; the control grafts were treated with venous blood only. Hematoxylin and eosin, immunocytochemical, and AgNO 3 staining demonstrated significant increases of surface endothelialization on the seeded grafts (92% ± 3.4% vs 26.6% ± 7.6%; P  = .0001) with markedly increased microvessels in the neointima, graft wall, and external area compared with controls. In dogs, CD34 + cell seeding enhances vascular graft endothelialization; this suggests practical therapeutic applications.