Sintered S53P4 bioactive glass scaffolds have anti-inflammatory properties and stimulate osteogenesis in vitro

Abstract

Bioactive glasses (BAG) are used as bone-graft substitutes in orthopaedic surgery. A specific BAG scaffold was developed by sintering BAG-S53P4 granules. It is hypothesised that this scaffold can be used as a bone substitute to fill bone defects and induce a bioactive membrane (IM) around the defect site. Beyond providing the scaffold increased mechanical strength, that the initial inflammatory reaction and subsequent IM formation can be enhanced by coating the scaffolds with poly(DL-lactide-co-glycolide) (PLGA) is also hypothesised. To study the immunomodulatory effects, BAG-S53P4 (± PLGA) scaffolds were placed on monolayers of primary human macrophage cultures and the production of various pro- and anti-inflammatory cytokines was assessed using reverse transcriptase quantitative polymerase chain reaction (RT-qPCR) and ELISA. To study the osteogenic effects, BAG-S53P4 (± PLGA) scaffolds were cultured with rabbit mesenchymal stem cells and osteogenic differentiation was evaluated by RT-qPCR and matrix mineralisation assays. The scaffold ion release was quantified and the BAG surface reactivity visualised. Furthermore, the pH of culture media was measured. BAG-S53P4 scaffolds had both anti-inflammatory and osteogenic properties that were likely attributable to alkalinisation of the media and ion release from the scaffold. pH change, ion release, and immunomodulatory properties of the scaffold could be modulated by the PLGA coating. Contrary to the hypothesis, the coating functioned by attenuating the BAG surface reactions and subsequent anti-inflammatory properties, rather than inducing an elevated inflammatory response compared to BAG-S53P4 alone. These results further validated the use of BAG-S53P4 (± PLGA) scaffolds as bone substitutes and indicate that scaffold properties can be tailored to a specific clinical need.

Treatment of Infection-Related Non-Unions with Bioactive Glass—A Promising Approach or Just Another Method of Dead Space Management?

“…Interestingly µCT scans showed positive effects of S53P4 on the surrounding bone tissue with increased bone volume, indicating an osteoinductive effect of the bone graft substitute, at least under non-infected conditions as seen by other groups [47,48]. This early osteoinductive effect of S53P4 could even be detected in infected conditions 4 weeks after the second surgery.…”

Multi-leveled Nanosilicate Implants Can Facilitate Near-Perfect Bone Healing

“…We believe that this high expression of osteogenic protein markers may be attributed to the ions released from BG, including Ca, P, and Si, and the release of Laponite mineral constituents including Si, Li, and Mg, which all have a positive role in the osteogenic differentiation according to the recent literature. 45 , 49 , 51 , 108 , 109 Additionally, we evaluated the osteogenic capacity of all combinations by looking at ALP expression and activity. It was found that BGH showed significantly more ALP positively stained areas and resulted in higher ALP activity compared to the other groups in both (±) differentiation media after 1 and 2 weeks.…”

Enchondromas of the Hand: Curettage With Autogenous Bonevs.Bioactive Glass S53P4 for Void Augmentation

“…BAG-S53P4 is a safe and well-tolerated bone-graft material and has successfully been used in the treatment of bone cysts and cavities, including treatment of those arising from infection. Bone formation in experimental in vitro and in vivo bone defect models of BAG-S53P4 has been well documented (24,25).…”