Human recombinant cementum protein 1, dental pulp stem cells, and PLGA/hydroxyapatite scaffold as substitute biomaterial in critical size osseous defect repair in vivo.

Objective: To evaluate the healing response of critical defects in rat calvaria with recombinant cementum protein 1 (hrCEMP-1) combined with human dental pulp stem cells (hDPSC) and polylactide-co-glycolide/hydroxyapatite (PLGA/HA) scaffold.

Methods: The effect of hrCEMP-1 on proliferation and differentiation of human dental stem cells (hDPSCs) toward a mineralizing-like phenotype was evaluated in monolayer and PLGA/HA scaffold by qPCR. 5 mm calvarial defects were created in Wistar rats and filled with: 1) PLGA/HA scaffold; 2) hDPSCs-PLGA/HA scaffold; 3) hrCEMP-1-hDPSc-PLGA/HA scaffold; 4) control (without scaffold). Bone formation was evaluated by histological-histomorphometric analysis, scanning electron microscopy (SEM) and radiographic evaluation. Comparisons between groups were made with a one-way analysis of variance ANOVA and Bonferroni post-hoc test.

Results: In vitro results showed that the PLGA/HA scaffold loaded with hrCEMP-1 improved the proliferation and differentiation of hDPSCs towards a mineralization phenotype by inducing mRNA expression of ALP, OSX, RUNX2, OP, and COL-I genes. The hrCEMP-1/hDPSCs/-PLGA/HA scaffold resulted only in connective tissue formed after ten weeks of healing, larger central radiolucency, and a low peripheral density. We showed superior bone growth and repair with a PLGA/HA matrix scaffold alone and containing hDPSCs compared to the hrCEMP/cells group.

Conclusions: PLGA/HA scaffold with hrCEMP-1 induces hDPSC commitment to mineralizing phenotype in vitro, but does not promote critical size osseous defect repair in vivo when it is included in a substitute biomaterial with hDPSc-PLGA/HA scaffold.