Therapeutic potential of adipose-derived stromal cells in age-related osteoporosis.

Adipose-derived stromal cells (ASCs) are increasingly being used for orthopedic-based tissue engineering approaches due to their ability to readily undergo osteogenic differentiation. In the present study, we used in vitro and in vivo approaches to evaluate the use of ASCs as a treatment strategy for age-related osteoporosis. Molecular, histological and micro-computed tomography (micro-CT) based approaches confirmed that ASCs isolated from 18-week-old osteoporotic senescence-accelerated mice (SAMP6) were capable of undergoing osteogenesis when cultured in either silk fibroin (SF) scaffolds or scaffold-free microtissues (ASC-MT). A single intratibial injection of CM-Dil-labeled isogeneic ASCs or ASC-MT into SAMP6 recipients significantly improved trabecular bone quality after 6 weeks in comparison to untreated contralateral bones, as determined by micro-CT. Injected ASCs could be observed in paraffin wax bone sections at 24 h and 6 weeks post treatment and induced a significant increase in several molecular markers of bone turnover. Furthermore, a significant improvement in the osteogenic potential of osteoporotic patient-derived human bone marrow stromal cells (BMSCs) was observed when differentiated in conditioned culture media harvested from osteoporotic patient-derived human ASCs. These findings therefore support the use of ASCs as an autologous cell-based approach for the treatment of osteoporosis.