Assessment of the osteogenic potential of alendronate on isolated adipose-derived stem cells: an ex-vivo and in-vivo study

ABSTRACT

Tissue engineering relies on the principle that mesenchymal stem cells are capable of differentiating to optimize almost all craniofacial structures. Temporary biomimetic scaffolds are necessary for accommodating cell growth and tissue genesis. The aim of this study was to evaluate the effect of alendronate on adipose-derived stem cells [ADSCs] from dogs and to compare bone regeneration in critical-sized calvarial bone defect in dogs using ADSCs in the presence and the absence of locally delivered alendronate. Seven dogs were used for the study. After isolating the adipose tissue from the inguinal pad of fat, stem cells were harvested and expanded in culture. The effect of alendronate 1 mg/ml on stem cells' osteogenic differentiation was tested for 7 days. Three critical-sized calvarial defects were created in each dog. One defect was filled with stem cells seeded on a chitosan scaffold and soaked in an osteogenic media, the second was fi lled with stem cells seeded on a chitosan scaffold and soaked with osteogenic medium, and the third one was fi lled with stem cells seeded on a chitosan scaffold. Bone formation was tested histologically after 8 weeks in each defect. Alendronate is capable of inducing osteogenic differentiation of ADSCs after 7 days of in-vitro culture. Bones such as trabeculae were deposited in alendronate and osteogenic medium defects, whereas the control group showed only fibrous tissue formation. There was no statistically significant difference in the surface area of the deposited bone trabeculae between the alendronate group and the osteogenic medium group. The surface area of individual bone trabeculae in this group was 147.99 +/- 14.803 compared with the osteogenic group. Alendronate may be used locally at a concentration of 10 mg/ml to induce osteogenic differentiation of ADSCs both in vitro and in vivo. The combination of a local, short-term alendronate treatment with ADSCs and biodegradable chitosan scaffold enhances the bone repair of a critical-sized calvarial defect in vivo