Fibroin Scaffold repairs critical size bone defects in vivo supported by Human Amniotic Fluid and Dental Pulp Stem Cells

The main aim of this study is to evaluate potential of fibroin scaffold combined with human stem cells, such as dental pulp stem cells (hDPSC) and amniotic fluid stem cells (hAFSCs), to reconstruct critical size cranial bone defects in animal model. We performed two symmetric full-thickness cranial defects on each parietal region of rats and we replenished them with collagen or silk fibroin scaffolds with or without stem cells already seeded into and addressed towards osteogenic lineage in vitro. Animals were euthanized after 4 weeks postoperatively and cranial tissue samples were taken for histological analysis. The presence of human cells in the new-formed bone was confirmed by confocal analysis with an antibody directed to a human mitochondrial protein. We observed a mature bone formation and the most relevant defect correction in constructs with fibroin. Moreover bone production by hAFSCs was appreciably higher. Our findings demonstrated the strong potential of bioengineered constructs of stem cell-fibroin scaffold for correcting large cranial defects in animal model and constitutes a promising approach for reconstruction of human large skeletal defects in craniofacial surgery.