Vancomycin Containing PDLLA and PLGA/ß-TCP Inhibit Biofilm Formation but Do Not Stimulate Osteogenic Transformation of Human Mesenchymal Stem Cells.

Aims: Chronic osteomyelitis, including implant-related prosthetic joint infection, is extremely difficult to cure. We develop vancomycin containing release systems from poly(d,l-lactide) (PDLLA) and poly(d,l-lactide-co-glycolide) (PLGA) composites with beta-tricalcium phosphate (ß-TCP) to treat methicillin-resistant Staphylococcus aureus osteomyelitis. We ask whether vancomycin containing PDLLA/ß-TCP and PLGA/ß-TCP composites will prevent early biofilm formation, allow cell proliferation and osteogenic differentiation, and stimulate osteogenic signaling molecules in the absence of an osteogenic medium. Methods: Composites were produced and characterized with scanning electron microscopy. In vitro vancomycin release was assessed for 6 weeks. Biofilm prevention was calculated by crystal violet staining. Human bone marrow-derived mesenchymal stem cells (hBM-MSCs) and osteosarcoma cell (SaOS-2) proliferation and differentiation were assessed with water soluble tetrazolium salt and alkaline phosphatase (ALP) staining. Real-time quantitative polymerase chain reaction defined osteogenic signaling molecules for hBM-MSCs. Results: Totally, 3.1 ± 0.2 mg and 3.4 ± 0.4 mg vancomycin released from PDLLA/ß-TCP and the PLGA/ß-TCP composites, respectively, and inhibited early biofilm formation. hBM-MSCs and SaOS-2 cells proliferated on the composites and stimulated ALP activity of cells. Runt-related transcription factor 2 (RUNX2) and SRY-Box transcription Factor 9 (SOX9) expressions were, however, lower with composites when compared with control. Conclusion: Vancomycin containing PDLLA/ß-TCP and PLGA/ß-TCP composites inhibited early biofilm formation and proliferated and differentiated hBM-MSCs and SaOS-2 cells, but osteogenesis-related RUNX2 and SOX9 transcription factors were not strongly expressed in the absence of an osteogenic medium for 14 days.

Stem Cell and Advanced Nano Bioceramic Interactions.

Bioceramics are type of biomaterials generally used for orthopaedic applications due to their similar structure with bone. Especially regarding to their osteoinductivity and osteoconductivity, they are used as biodegradable scaffolds for bone regeneration along with mesenchymal stem cells. Since chemical properties of bioceramics are important for regeneration of tissue, physical properties are also important for cell proliferation. In this respect, several different manufacturing methods are used for manufacturing nano scale bioceramics. These nano scale bioceramics are used for regeneration of bone and cartilage both alone or with other types of biomaterials. They can also act as carrier for the delivery of drugs in musculoskeletal infections without causing any systemic toxicity.

Vancomycin containing PLLA/ß-TCP controls MRSA in vitro.

BACKGROUND: Osteomyelitis caused by Methicillin-resistant Staphylococcus aureus (MRSA) often requires surgery and prolonged systemic antibiotic treatment. Local antibiotic delivery systems of bioceramics or polymers have been developed to treat osteomyelitis. A disadvantage of biodegradable polymers is the initial burst of antibiotics into the environment; one advantage of bioceramics is its osteoconductivity. We therefore developed a vancomycin-containing poly-l-lactic acid/ß-tricalcium phosphate (PLLA/ß-TCP) composite to control antibiotic release and stimulate bone formation. QUESTIONS/PURPOSES: We (1) characterized these composites, (2) assessed vancomycin release in inhibitory doses, and (3) determined whether they would permit cell adhesion, proliferation, and mineralization in vitro. METHODS: We molded 250 vancomycin-containing (VC) and 125 vancomycin-free (VUC) composites using PLLA, ß-TCP, and chloroform. One hundred twenty-five VC composites were further dip-coated with PLLA (CVC) to delay antibiotic release. Composites were characterized according to their pore structure, size, volume, density, and surface area. Vancomycin release and bioactivity were determined. Adhesion, proliferation, and mineralization were assessed for two and three replicates on Days 3 and 7 with mesenchymal stem (MSC) and Saos type 2 cells. RESULTS: Pore size, volume, apparent density, and surface area of the CVC were 3.5 ± 1.9 µm, 0.005 ± 0.002 cm(3)/g, 1.18 g/cm(3) and 3.68 m(2)/g, respectively. CVC released 1.71 ± 0.13 mg (63.1%) and 2.49 ± 0.64 mg (91.9%) of its vancomycin on Day 1 and Week 6, respectively. MSC and Saos type 2 cells attached and proliferated on composites on Days 3 and 7. CONCLUSIONS: Vancomycin-containing PLLA/ß-TCP composites release antibiotics in inhibitory doses after dip coating and appeared biocompatible based on adhesion, proliferation, and mineralization. CLINICAL RELEVANCE: Vancomycin-containing PLLA/ß-TCP composites may be useful for controlling MRSA but will require in vivo confirmation.