Osteoinductive potential of small intestinal submucosa/ demineralized bone matrix as composite scaffolds for bone tissue engineering

Background: Demineralized bone matrix (DBM) is extensively used in orthopedic, periodontal, and maxillofacial application and investigated as a material to induce new bone formation. Small intestinal submucosa (SIS) derived from the submucosa layer of porcine intestine has widely utilized as biomaterial with minimum immune response. Objectives: Determine the osteoinductive potential of SIS, DBM, SIS/DBM composites in the in vitro cell culture and in vivo animal bioassays for bone tissue engineering. Materials and methods: Human periosteal (HPO) cells were treated in the absence or presence SIS, DBM, and SIS/DBM. Cell proliferation was examined by direct cell counting. Osteoblast differentiation of the HPO cells was analyzed with alkaline phosphatase activity assay. The Wistar rat muscle implant model was used to evaluate the osteoinductive potential of SIS, DBM, and SIS/DBM composites. Results: HPO cells could differentiate along osteogenic lineage when treated with either DBM or SIS/DBM. SIS/ DBM had a tendency to promote more cellular proliferation and osteoblast differentiation than the other treatments. In Wistar rat bioassay, SIS showed no new bone formation and the implants were surrounded by fibrous tissues. DBM demonstrated new bone formation along the edge of old DBM particles. SIS/DBM composite exhibited high osteoinductivity, and the residual SIS/DBM was surrounded by osteoid-like matrix and newly formed bone. Conclusion: DBM and SIS/DBM composites could retain their osteoinductive capability. SIS/DBM scaffolds may provide an alternative approach for bone tissue engineering.