Distinctions in bone matrix nanostructure, composition, and formation between osteoblast-like cells, MG-63, and human mesenchymal stem cells, UE7T-13

Osteoblast-like cells and human mesenchymal stem cells (hMSCs) are frequently employed as osteoprogenitor cell models for evaluating novel biomaterials in bone healing and tissue engineering. In this study, the characterization of UE7T-13 hMSCs and MG-63 human osteoblast-like cells was examined. Both cells can undergo osteogenesis and produce calcium extracellular matrix; however, calcium nodules produced by MG-63 lacked a central mass and appeared flatter than UE7T-13. The absence of growing calcium nodules in MG-63 was discovered by SEM-EDX to be associated with the formation of alternating layers of cells and calcium extracellular matrix. The nanostructure and composition analysis showed that UE7T-13 had a finer nanostructure of calcium nodules with a higher calcium/phosphate ratio than MG-63. Both cells expressed high intrinsic levels of collagen type I alpha 1 chain, while only UE7T-13 expressed high levels of alkaline phosphatase, biomineralization associated (ALPL). High ALP activity in UE7T-13 was not further enhanced by osteogenic induction, but in MG-63, low intrinsic ALP activity was greatly induced by osteogenic induction. These findings highlight the differences between the two immortal osteoprogenitor cell lines, along with some technical notes that should be considered while selecting and interpreting the pertinent in vitro model.