Methods: Briefly, we examined the effect of single or dual administration of antibiotic, vancomycin (VAN) at 0-16μg/mL and bone morphogenetic protein 2 (BMP-2) at 0-100ng/mL to both methicillin sensitive S. aureus (the major offender in bone graft infection) and mouse bone marrow stromal cells (mBMSC) in both mono and co-culture conditions. Cell metabolic activity, live/dead staining, dsDNA amount, and alkaline phosphatase activity were measured to assess cell viability, proliferation and differentiation. An interleukin-6 ELISA kit was used to test the bone cell inflammation response in the presence of bacteria.
Results: Our results indicate that when delivered together in co-culture, VAN and BMP-2 maintain their primary functions as an antibiotic and growth factor respectively. Most interestingly, this dual-delivery type of approach has shown itself to be effective at lower concentrations of VAN than an approach relying strictly on the antibiotic.
Conclusion: It may be that BMP-2 gives the mBMSCs a greater chance to proliferate and differentiate before becoming infected. To our knowledge, this study is the first to demonstrate that a lower concentration of vancomycin in treatments with BMP-2 was necessary to achieve almost complete suppression of bacterial growth compared to treatments without BMP-2.
Keywords: Antimicrobials, Bacterial, Biomaterials, Bone repair and Cell culture