Peripheral blood-derived endothelial progenitor cells enhance vertical bone formation.

ABSTRACT

BACKGROUND: This study presents a novel cell-based approach for extra-cortical bone regeneration. OBJECTIVE: To enhance vertical bone formation by combining guided bone regeneration and transplantation of peripheral blood-derived endothelial progenitor cells (EPCs) in a rat calvaria model. MATERIALS AND METHODS: EPCs were isolated from peripheral blood of inbred rats. Gold domes (7 mm radius, 5 mm height) were filled with ß-tricalcium phosphate (ßTCP) mixed with 5 × 10(5) EPC. Domes filled with ßTCP served as control (CNT). Rats were sacrificed after 3 months. Vertical bone augmentation was analyzed using histology, histomorphometry, and microcomputed tomography (µCT). RESULTS: In all rats, hard tissue filled the space under the dome. Histomorphometric analysis revealed that EPC transplantations doubled vertical bone height (EPC 4.04 ± 0.22 mm vs CNT 2.29 ± 0.22 mm, p ≤ .001). EPC also caused ∼50% increase in bone area fraction (EPC 47.3 ± 3.1% vs CNT 31.1 ± 2.7%, p ≤ .003). µCT results also showed that bone volume fraction (BV/TV) was higher in EPC group (p = .0169). In both groups, BV/TV declined from the bottom to the top of the samples. No differences in tissue mineral density were found between EPC and CNT groups. CONCLUSION: EPC transplantation significantly improved bone formation especially in the areas that are remote from the original bone.