Background: Vancomycin is widely used to treat infected bone defects in orthopedic surgery. Several reports highlighted a beneficial outcome if vancomycin-impregnated bone cement was used, but there is little information of direct vancomycin effects on human mesenchymal stem cells (MSCs).
Methods: MSCs were harvested from patients who underwent iliac bone grafting for spine fusion. Cells were cultured in complete medium or osteogenic induction medium. The cytotoxicity assay for vancomycin (range from 0 to 2000 μg/ml) was determined by using WST-1 reagent. After vancomycin (100 μg/ml) treatment, the expression of osteogenic gene was determined by Q-PCR. The alkaline phosphatase (ALP) activity, calcium level, and intensity of Alizarin Red staining of the MSCs were assessed. Protein expression of osteopontin (OPN) and cbfa-1 were detected by western blotting. Phosphorylation of p38 or ERK was evaluated by phospho-kinase array kit.
Results: Vancomycin did not affect cell proliferation until high concentrations (500 ug/ml) for long-termed incubation (14 days). After vancomycin treatment (100 μg/ml), mRNA expression of type I collagen, OPN, Cbfa1 and osteocalcin (OSC) were up-regulated and increased ALP activity and calcium levels were noted. Increased protein expression of OPN and cbfa-1 was shown after vancomycin treatment. Positive Alizarin Red staining through the matrix at the surface layer of the vancomycin treated group was greater than that of the control group. Phosphorylation of p38 and ERK were increased after vancomycin treatment.
Conclusion: Vancomycin dose dependently promotes osteogenic differentiation of MSCs in vitro. Whether MAPK signalling play an important role in these effects remains to be investigated.
Disclosure: The authors declared no competing interests.