Endothelial progenitor cells promote fracture healing in a segmental bone defect model.
The objective of this study was to evaluate the effects of local endothelial progenitor cell (EPC) therapy on bone regeneration in a rat model. A segmental bone defect (5 mm) was created in the femur and fixed with a mini-plate. There were two groups: EPC-treated (N = 28) and control (N = 28). Seven animals were sacrificed from each group at 1, 2, 3, and 10 weeks postoperatively. Healing of the defect was evaluated with radiographic, histological, and quantitative micro-computed tomography (micro-CT) scans. Radiographically, mean scores of the EPC and control groups were, respectively, 1.16-0.61 (p < 0.05) at 1 week, 2.53-1.54 (p < 0.05) at 2 weeks, and 4.58-2.35 at 3 weeks (p < 0.05). At 10 weeks, all the animals in the EPC-treated group had complete union (7/7), but in the control group none achieved union (0/7). Histological evaluation revealed that specimens from EPC-treated animals had abundant new bone and vessel formation compared to that in controls. Micro-CT assessment of the samples from the animals sacrificed at 10 weeks (N = 14) showed significantly improved parameters of bone volume (36.58-10.57, p = 0.000), bone volume density (0.26-0.17, p = 0.000), model index -2.22-2.79, p = 0.000), trabecular number (1.28-0.91, p = 0.063), trabecular thickness (0.21-0.15, p = 0.001), trabecular spacing (0.63-1.07, p = 0.022), bone surface (353.75-152.08, p = 0.000), and bone surface to bone volume ratio (9.54-14.24, p = 0.004) for the EPC group compared to control, respectively. In conclusion, local EPC therapy significantly enhanced bone regeneration in a segmental defect model in rat femur diaphysis.
The Keenan Research Centre of the Li Ka Shing Knowledge Institute of St. Michael's Hospital and the Musculoskeletal Research Laboratory, Division of Orthopaedic Surgery, University of Toronto, 30 Bond Street, Toronto, Ontario M5B IW8, Canada.
Kivanc
K
Atesok
Ru
R
Li
Duncan J
DJ
Stewart
Emil H
EH
Schemitsch
D000818:Animals; D001860:Bone Plates; D001861:Bone Regeneration / Q000502:physiology*; D004195:Disease Models, Animal; D042783:Endothelial Cells / Q000166:cytology; D005264:Femoral Fractures / Q000628:therapy*; D017102:Fracture Healing / Q000502:physiology*; D008297:Male; D018919:Neovascularization, Physiologic; D051381:Rats; D011916:Rats, Inbred F344; D033581:Stem Cell Transplantation; D013234:Stem Cells / Q000166:cytology / Q000502:physiology*