Using osteogenic medium in the in vitro evaluation of bone biomaterials: Artefacts due to a synergistic effect

In vitro tests using bone cells to evaluate the osteogenic potential of biomaterials usually employ the osteogenic medium (OM). The lack of correlation frequently reported between in vitro and in vivo studies in bone biomaterials, makes necessary the evaluation of the impact of osteogenic supplements on these results. This study analysed the proteomic profiles of human osteoblasts (HOb) cultured in the media with and without osteogenic agents (ascorbic acid and β-glycerol phosphate). The cells were incubated for 1 and 7 days, on their own or in contact with Ti. The comparative Perseus analysis identified 2544 proteins whose expression was affected by osteogenic agents. We observed that the OM strongly alters protein expression profiles with a complex impact on multiple pathways associated with adhesion, immunity, oxidative stress, coagulation, angiogenesis and osteogenesis. OM-triggered changes in the HOb intracellular energy production mechanisms, with key roles in osteoblast maturation. HOb cultured with and without Ti showed enrichment in the skeletal system development function due to the OM. However, differentially expressed proteins with key regenerative functions were associated with a synergistic effect of OM and Ti. This synergy, caused by the Ti–OM interaction, could complicate the interpretation of in vitro results, highlighting the need to analyse this phenomenon in biomaterial testing. Human osteoblasts (HObs) cultured on Ti and without this biomaterial using culture media supplemented and non-supplemented with osteogenic agents were characterized by proteomics. The comparative analyses of the proteomic profiles associated to the different conditions allowed to identify differentially expressed proteins with key regenerative functions related to a synergistic effect of the osteogenic media and the Ti. [Display omitted] •The osteogenic supplements affect the entire cellular mechanism of HOb cells.•Differences in the HOb proteome expression were identified due to Ti.•Synergistic effects between the osteogenic medium and Ti were identified.