Mouse adipose-derived mesenchymal stromal cells undergo osteogenic differentiation in vitro and in vivo

Abstract

Abstract Introduction: Although the multilineage potential of human processed lipoaspirate has previously been demonstrated, few studies exist utilizing mouse adipose-derived mesenchymal cells (ADMSCs) in vitro or in vivo. Here, we develop a method for osteogenic differentiation of ADMSCs in vitro and utilize them to repair calvarial defects in vivo. Methods: ADMSCs were harvested from 3 week old female FVB mice. ADMSCs were cultured in standard osteogenic media with various concentrations of BMP-2 or retinoic acid (RA) for 3 weeks. Growth and differentiation were assessed via cell counting, Oil Red O (ORO), alkaline phosphatase (AP), and von Kossa (VK) staining. Apatite-coated poly-lactic co-glycolic acid (PLGA) scaffolds were then seeded with ADMSCs and implanted into critical sized (4mm) calvarial defects in adult male mice. Calvarial regeneration was assessed using histology and radiography. Results: Only slight differences in proliferation were seen in response to BMP2, RA, or BMP2 + RA. ORO staining was dramatically decreased in treated cells. AP and von Kossa staining were induced in a synergistic fashion by BMP2 + RA. In vivo experiments revealed successful healing of calvarial defects by 12 weeks after surgery. ADMSC-seeded scaffolds produced significant intramembranous bone formation by 2 weeks, and areas of complete bony bridging by 12 weeks as demonstrated by X-ray and histology. Conclusions: Our data demonstrate successful osteogenic differentiation of ADMSCs in vitro and in vivo. This novel mouse model potentiates further investigation into the mechanisms governing osteogenesis and the epigenetic manipulations that can be used to enhance this process.