Repair of a Calvarial Defect With Biofactor and Stem Cell–Embedded Polyethylene Glycol Scaffold

Abstract

Segmental bony defects resulting from congenital facial anomalies, facial trauma, infection, or oncologic surgical resection represent a common and significant clinical problem. Currently, these defects are reconstructed with autologous or allogeneic bone grafts or prosthetic devices. These options are limited by bone supply for grafting, donor site morbidity, risk of infection, and extrusion. This study investigated the in vivo osteogenic capability of polyethylene glycol-diacrylate (PEG-DA) and a protease-sensitive PEG matrix metalloproteinases (PEG-MMP), photoencapsulated with mesenchymal stem cells (MSCs) and bone morphogenetic protein (BMP)-2, in healing a critical-size rat calvarial defect. Both PEG-DA and PEG-MMP scaffolds photoencapsulated with rat MSCs (rMSCs) and/or BMP-2 were implanted into a critical-size defect. Microcomputed-tomographic (micro-CT) analysis was completed 1, 4, and 8 weeks after implantation. Bone growth was histologically evaluated. The micro-CT data were analyzed using ASPIProVM software to calculate the percentage of closure of cranial defects. Both PEG-MMP and PEG-MMP + BMP2 showed significantly enhanced bone compared with controls. Polyethylene glycol-diacrylate seemed to inhibit bone growth regardless of biofactor and rMSCs. The addition of rMSCs did not enhance bone regeneration. Polyethylene glycol sensitive to proteolysis significantly improved bone repair in a critical-size calvarial defect.