Enhanced bone formation by marrow-derived endothelial and osteogenic cell transplantation

Bone marrow-derived osteogenic cells can regenerate bone tissues in vivo. The aim of the present study is to determine whether the cotransplantation of bone marrowderived endothelial-like cells (BMECs) enhances bone regeneration by bone marrow-derived osteogenic cell (BMOC) transplantation in osseous defects. Canine bone marrow cells were differentiated separately into BMECs and BMOCs. Using apatite-coated poly(lactide-co-glycolide)/hydroxyapatite composite scaffolds as cell delivery vehicles, BMOCs were transplanted with or without BMECs into critical-sized calvarial defects in immunodeficient mice. Histological analyses, microcomputed tomography, and soft X-ray were performed to assess mineralized bone formation at 8 weeks. Cotransplantation of BMECs and BMOCs resulted in greater bone formation than transplantation of BMOCs alone. There was a significant (p < 0.05) increase in bone formation area following cotransplantation (30.8% ± 2.5%), compared with transplantation of BMOCs alone (15.3% 6± 1.9%). These results demonstrate that the cotransplantation of BMECs enhances bone regeneration mediated by BMOC transplantation in osseous defects.