Regeneration of Periosteum by Human Bone Marrow Stromal Cell Sheets

Purpose The presence of a functional periosteum accelerates healing in bone defects by providing a source of progenitor cells that aid in repair. We hypothesized that bone marrow stromal cell (BMSC) sheets could be used to engineer functional periosteal tissues. Materials and Methods BMSCs were cultured to hyperconfluence and produced sufficient extracellular matrix to form robust tissue sheets. The sheets were wrapped around calcium phosphate pellets and implanted subcutaneously in mice for 8 weeks. Histologic comparisons were made between calcium phosphate samples with and without BMSC sheet wraps. Bone and periosteum formation were analyzed through tissue morphology and tissue-specific protein expression. Results Calcium phosphate pellets wrapped in BMSC sheets regenerated a bone-like tissue, but pellets lacking the cell sheet wrap did not. The bone-like tissue seen on the calcium phosphate scaffolds wrapped with the BMSC sheets was enclosed within a periosteum-like tissue characterized morphologically and through expression of periostin. Conclusions These data indicate that cell sheet technology has potential for regenerating a functional periosteum-like tissue that could aid in future orthopedic therapy.