Impact of High-Dose Anti-Infective Agents on the Osteogenic Response of Mesenchymal Stem Cells

Abstract

Treatment of infected nonunions and severe bone infections is a huge challenge in modern orthopedics. Their treatment routinely includes the use of anti-infective agents. Although frequently used, little is known about their impact on the osteogenesis of mesenchymal stem cells. In a high- and low-dose set-up, this study evaluates the effects of the antibiotics Gentamicin and Vancomycin as well as the antifungal agent Voriconazole on the ability of mesenchymal stem cells to differentiate into osteoblast-like cells and synthesize hydroxyapatite in a monolayer cell culture. The osteogenic activity was assessed by measuring calcium and phosphate concentrations as well as alkaline phosphatase activity and osteocalcin concentration in the cell culture medium supernatant. The amount of hydroxyapatite was measured directly by radioactive 99mTechnetium-HDP labeling. Regarding the osteogenic markers, it could be concluded that the osteogenesis was successful within the groups treated with osteogenic cell culture media. The results revealed that all anti-infective agents have a cytotoxic effect on mesenchymal stem cells, especially in higher concentrations, whereas the measured absolute amount of hydroxyapatite was independent of the anti-infective agent used. Normed to the number of cells it can therefore be concluded that the above-mentioned anti-infective agents actually have a positive effect on osteogenesis while high-dose Gentamycin, in particular, is apparently capable of boosting the deposition of minerals.

Impact of Antibiotic-Loaded PMMA Spacers on the Osteogenic Potential of hMSCs

“…For Gentamicin and Vancomycin, it seems that the reduction in cell number does not lead to a reduction in osteogenic potential. These results are consistent with earlier findings [27]. In a study from 2021, we showed that osteogenically differentiated BM-hMSCs cultures always showed an uptake of around 3.5 MBq, whether antibiotics were added to the cell culture medium or not.…”

“…In our data, the calcium concentration was significantly lower for all osteogenic conditions when compared to the control conditions. Vice versa, high phosphate concentrations probably correlate with osteogenesis [27]. In our data, the phosphate concentration was always significantly higher for the osteogenic groups.…”

“…Still, when comparing the cell counts of groups containing antibiotics (groups 3-6) and groups without antibiotics (groups 1 and 2), it seems clear that a reduction in the cell count takes place. This same effect could be shown when directly adding antibiotics to the cell culture medium: the presence of Gentamicin and Vancomycin led to a reduction in the number of cells in the culture [27]. Therefore, two things can be concluded: Firstly, Vancomycin and Gentamicin are cytotoxic, especially at higher doses.…”

“…This would lead to an impaired osteogenesis, prolonging the healing process. However, in vitro data suggest that, whereas Gentamicin is especially effective in reducing the cell count of a cell culture when added directly to the cell culture medium, there is no reduction in overall osteogenic potential due to a relatively higher osteogenic activity in the cells [27].…”

Wrap It! Preventive Antimicrobial Treatment Shows No Negative Effects on Tenocytes and Tendons—A Comprehensive Approach

“…Since its discovery in the 1950s, vancomycin has become widely used because of its excellent activity against both Clostridium difficile in pseudomembranous enterocolitis and methicillin-resistant Staphylococcus aureus (MRSA) [ 21 ]. Regardless of its beneficial effects, vancomycin is also known for having cytotoxic effects on mesenchymal stromal cells and osteoblasts, as well as chondrocytes [ 22 , 23 , 24 , 25 ]. A meta-analysis on the effect of intrawound vancomycin powder application (1–2 g) in knee and hip arthroplasty revealed an effective infection prophylaxis but an increase in aseptic wound complications [ 26 ], raising concerns about the healing process.…”