Potent Osteogenesis and Chondrogenesis of CD34-Enriched Mouse Adipose-Derived Stem Cells

Adipose-derived stem cells (ASCs) obtained using a widely reported culture method are actually a heterozygous cell population of the adipose stromal vascular fraction (SVF). This heterogeneity may interfere with the multi-differentiation potential of adipose-derived mesenchymal stem cells (ADMSCs). It is therefore necessary to establish an efficient method for isolating ADMSCs that have high multi-differentiation potential. Several studies indicated that mucosialin (CD34) might be one of the specific markers of ADMSCs. In our previous studies, a CD34-enriched cell population sorted from the pooled SVF had stronger differentiation potential than that of unsorted cells in a hair follicle morphogenesis model. However, it remains unclear whether CD34-enriched cells have stronger potential for other lineage differentiation, particularly osteogenesis and chondrogenesis. In this study, CD34(+) cells were harvested and sorted from murine adipose-derived cells and their potentials for osteogenesis and chondrogesis were examined using engineered bone and cartilage models. The results show that CD34(+) cells exhibited stronger potential for bone formation with stronger van Gieson and collagen I staining than those of CD34(-) cells and an unsorted SVF when seeded on beta-tricalcium phosphate. Furthermore, CD34(+) cells also exhibited a much stronger chondrogenic potential than those of CD34(-) cells and an unsorted SVF, with stronger staining of toluidine blue, Safranin-O, and collagen II in a chondrocyte pellet and engineered cartilage. Most importantly, only CD34(+) cells could form a cartilage-like lacunae structure. All these results indicate that CD34(-) may serve as a specific surface marker for enriching ADMSCs in ASCs.