Phytic acid improves osteogenesis and inhibits the senescence of human bone marrow mesenchymal stem cells under high-glucose conditions via the ERK pathway.

Hyperglycaemia causes impairment of osteogenic differentiation and accelerates stem cell senescence, resulting in weakened osteogenesis and disordered bone metabolism. Phytic acid (PA) is an antioxidant that is reportedly beneficial to bone homeostasis. The present study aims to clarify how PA affects the osteogenic capacity and cellular senescence of bone marrow mesenchymal stem cells (BMSCs) exposed to high-glucose environments, as well as the potential molecular mechanisms. Our results indicate that osteogenic differentiation in BMSCs cultivated in high-glucose conditions is enhanced by PA, as evidenced by increased alkaline phosphatase activity and staining, Alizarin Red S staining, osteogenic marker in in vitro studies, and increased osteogenesis in animal experiments. PA also prevented high-glucose-induced senescence of BMSCs, as evidenced by the repression of reactive oxygen species production, senescence-associated ß-galactosidase staining, and P21 and P53 expression. Furthermore, it was found that PA rescued the high-glucose-inhibited expression of phosphorylated extracellular regulated protein kinases (p-ERK). The inhibition of ERK pathway by the specific inhibitor PD98059 blocked the PA-enhanced osteogenesis of BMSCs and promoted cell senescence. Our results revealed that PA enhances osteogenic differentiation and inhibits BMSC senescence in a high-glucose environment. In addition, the activation of the ERK pathway seems to mediate the beneficial effects of PA. The findings provide novel insights that could facilitate bone regeneration in patients with diabetes.

Bioinspired Synthesis of Ag Nanoparticles onto Polytetrafluoroethylene with Enhanced Antibacterial Activity for Dental Implant Application.

BACKGROUND: Endosseous implants are widely used as a treatment for tooth loss, but gaps in the implant-abutment interface, and the cavity inside the implant, can cause inflammation of the tissue surrounding the implant. Currently available filling materials, however, cannot solve these problems. Therefore, the development of new antibacterial materials is key. In this study, we synthesized Ag nanoparticle-coated polytetrafluoroethylene (PTFE), analyzed the effect of Ag ion concentration, and estimated the antibacterial effects against oral pathogens in vitro. Method: The Ag nanoparticles (AgNPs)-modified PTFE was achieved using self-polymerized dopamine in an alkaline solution (2 mg/mL) and reduction reaction of Ag ions (0.01 mol/L and 0.05 mol/L). The surface features, chemical components, and wettability were characterized by scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS) and contact angle measurement. The antibacterial effect against Streptococcus mutans and Porphyromonas gingivalis was evaluated by counting colony-forming units on agar media and the visualization of bacteria present on the specimens by SEM and confocal laser scanning microscope (CLSM). RESULTS: The surface characterization results indicated that a polydopamine film was successfully formed on the PTFE membrane, and spherical AgNPs were successfully reduced. With increasing concentration of the Ag precursor, the contents of the AgNPs increased (p < 0.05). The antibacterial ratio of AgNP-coated PTFE against Streptococcus mutans and Porphyromonas gingivalis reached 94.2% and 80.6%, respectively. The results of antibacterial testing analyzed via SEM and CLSM also demonstrated the robust antibacterial ability of AgNPs-modified PTFE (p < 0.05). CONCLUSIONS: AgNPs-modified PTFE has great potential to function as an implant filling material with enhanced antibacterial properties, and has the potential to be a novel antimicrobial material for the prevention of peri-implantitis in the clinic.