Oxygen Tension-Controlled Matrices with Osteogenic and Vasculogenic Cells for Vascularized Bone Regeneration In Vivo

Tissue Eng Part A. 2016 Apr;22(7-8):610-20. doi: 10.1089/ten.TEA.2015.0310. Epub 2016 Mar 22.


Despite recent progress, segmental bone defect repair is still a significant challenge in orthopedic surgery. While bone tissue engineering approaches using biodegradable matrices along with bone/blood vessel forming cells offered improved possibilities, current regenerative strategies lack the ability to achieve vascularized bone regeneration in critical-sized/segmental bone defects. In this study, we introduced and evaluated a two-pronged approach for vascularized bone regeneration in vivo. The goal was to demonstrate vascularized bone formation using oxygen tension-controlled (OTC) matrices seeded with bone and blood vessel forming cells. OTC matrices were coimplanted with rabbit mesenchymal stem cells (MSCs) and peripheral blood-derived endothelial progenitor cells (PB-EPCs) to demonstrate the osteogenic and vasculogenic differentiation of these cells, postseeding on a matrix, especially deep inside the matrix pore structure. Matrices coimplanted with varied rabbit MSC and PB-EPC ratios (1:4, 1:1, and 4:1) were assessed in a nude mouse subcutaneous implantation model to determine a coimplantation ratio with superior osteogenic as well as vasculogenic properties. The implants were analyzed, at week 8, for endothelial (CD31 and Von Willebrand factor [vWF]) and osteogenic marker (RunX2 and Col I) staining qualitatively and collagen deposition and number of vessel formation quantitatively. Results from these experiments established MSC-to-PB-EPC ratio 1:1 as the best coimplantation ratio. OTC matrix with 1:1 coimplantation ratio was assessed for segmental bone defect repair in a rabbit critical-sized bone defect model. The group under investigation was OTC matrix, and the matrix was seeded with MSCs, EPCs, or MSCs:EPCs in a 1:1 ratio. Explants at week 12 were evaluated for bone defect repair via micro-CT and histology. Results from rabbit in vivo experiments show enhanced mineralization and vascularization for the 1:1 coimplantation group. Overall, the study establishes a two-pronged approach involving OTC matrix and effective progenitors for large-area and vascularized bone regeneration.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • Biomarkers / metabolism
  • Bone Regeneration / drug effects*
  • Disease Models, Animal
  • Endothelial Cells / cytology*
  • Endothelial Cells / drug effects
  • Fluorescent Antibody Technique
  • Implants, Experimental
  • Mesenchymal Stem Cells / cytology*
  • Mesenchymal Stem Cells / drug effects
  • Mice, SCID
  • Neovascularization, Physiologic / drug effects*
  • Osteogenesis / drug effects*
  • Oxygen / pharmacology*
  • Rabbits
  • Tissue Scaffolds / chemistry*
  • Ulna / diagnostic imaging
  • Ulna / drug effects
  • Ulna / pathology
  • X-Ray Microtomography


  • Biomarkers
  • Oxygen