Impact of Vancomycin Treatment on Human Mesenchymal Stromal Cells During Osteogenic Differentiation.

Background: Vancomycin is frequently applied locally to the operative site during foot and ankle procedures to help prevent infection. Although the efficacy of locally applied vancomycin has been demonstrated in spine surgery, there is no consensus on dosing and indication within foot and ankle surgery. Osteogenic differentiation of human mesenchymal stromal cells (hMSCs) is key to healing of both fractures and arthrodesis. The purpose of this research was to determine the impact of vancomycin on human hMSCs during the process of osteogenic differentiation. Methods: hMSCs were cultured in osteogenic differentiation media to promote osteogenic differentiation. Cells were treated with vancomycin at differing concentrations of 0, 50, 500, and 5000 mu g/mL. Viability and cell growth were assessed via LIVE/DEAD viability/cytotoxicity kit (Invitrogen, Waltham, MA) after 1, 3, and 7 days of vancomycin treatment. Differentiation and mineralization was assessed via alizarin red staining after 21 days of treatment. Mean cell viability, cell number, and mineralization were compared between treatment groups using 1-way analysis of variance and the Tukey-Kramer method for post hoc pairwise comparisons. Results: At the highest concentrations of vancomycin, there was a significant reduction in cell viability and proliferation after 3 days compared with all other treatment groups. Mineralization was also significantly decreased with higher doses of vancomycin. Conclusion: At high concentrations, vancomycin may impair hMSC viability and osteogenic differentiation. Clinical Relevance: Surgeons should exercise caution and consider the limited soft tissue envelope when applying vancomycin locally during foot and ankle surgery, especially during arthrodesis procedures.