Naringin inhibits titanium particles-induced up-regulation of TNF-α and IL-6 via the p38 MAPK pathway in fibroblasts from hip periprosthetic membrane.

AIMS: Inflammatory responses to wear debris cause osteolysis that leads to aseptic loosening and hip arthroplasty failure. Wear debris stimulate macrophages and fibroblasts to secret proinflammatory cytokines, including TNF-α and IL-6, which have been specifically implicated in periprosthetic osteolysis and osteoclast differentiation. Naringin has anti-inflammatory effect in macrophages. Moreover, naringin inhibited osteoclastogenesis and wear particles-induced osteolysis. In this study, we examined the potential inhibitory effects of naringin on titanium (Ti) particle-induced proinflammatory cytokines secretion in fibroblasts and the possible underlying molecular mechanisms. MATERIALS AND METHODS: Fibroblasts were isolated from periprosthetic membrane at the time of revision surgery performed due to aseptic loosening after hip arthroplasty and were cultured in the presence or absence of Ti particles, naringin and mitogen-activated protein kinase (MAPK) inhibitors, PD98059 (a selective inhibitor of ERK), SP600125 (a selective inhibitor of JNK), and SB203580 (a selective inhibitor of p38). TNF-α and IL-6 assays were performed using enzyme-linked immunosorbent assay kits. The phosphorylation levels of p38 and nuclear factor kappa B p65 (NF-κB p65) were examined by western blot. RESULTS: Naringin or SB203580 pretreatment significantly suppressed the secretion of TNF-α and IL-6 induced by titanium particles in fibroblasts, while inhibition of ERK or JNK pathways showed no effect on production of TNF-α and IL-6. Moreover, naringin inhibited Ti particle-induced phosphorylation of p38 and p65. CONCLUSIONS: These results indicated that naringin could inhibit Ti particle-induced inflammation in fibroblasts by inhibiting p38 MAPK/NF-κB p65 activity and might be a potential drug for the treatment of inflammatory periprosthetic osteolysis after arthroplasty.

Naringin increases osteoprotegerin expression in fibroblasts from periprosthetic membrane by the Wnt/ß-catenin signaling pathway.

BACKGROUND: The osteoclast bone resorption is critical in aseptic loosening after joint replacement. The balance between activator of nuclear factor kappa B ligand (RANKL) and osteoprotegerin (OPG) is considered to play a central role in osteoclast maturation. Fibroblasts from the periprosthetic membrane express RANKL and promote osteoclast formation. Studies have demonstrated that naringin inhibited osteoclastogenesis and wear particle-induced osteolysis. In this study, the naringin-induced OPG/RANKL effects and its underlying mechanism were studied in fibroblasts from periprosthetic membrane. METHODS: Fibroblasts were isolated from the periprosthetic membrane during hip arthroplasty for revision due to aseptic loosening. Fibroblasts were cultured and treated with or without naringin and DKK-1 (the classical inhibitor of Wnt/ß-catenin signaling pathway). OPG and RANKL mRNA and protein levels, gene expression of ß-catenin, and cyclin D1, which participate in the Wnt signaling pathway, were examined by real-time polymerase chain reaction and enzyme-linked immunosorbent assay. RESULTS: The mRNA and protein levels of OPG were enhanced by naringin in a dose-dependent manner compared to that of the non-treated control. In contrast, naringin did not affect the expression of RANKL. Importantly, DKK-1 attenuated OPG expression in fibroblasts under naringin treatment. Moreover, naringin stimulated the gene expression of ß-catenin and cyclin D1 in fibroblasts, and the effect could be inhibited by DKK-1. CONCLUSION: The results indicated that naringin enhanced OPG expression through Wnt/ß-catenin signaling pathway in fibroblasts from periprosthetic membrane, which may be useful to inhibit periprosthetic osteolysis during aseptic loosening after total joint arthroplasty.

Advances in Synthesis and Applications of Self-Healing Hydrogels.

BACKGROUND: Hydrogels, a type of three-dimensional (3-D) crosslinked network of polymers containing a high water concentration, have been receiving increasing attention in recent years. Self-healing hydrogels, which can return to their original structure and function after physical damage, are especially attractive. Some self-healable hydrogels have several kinds of properties such as injectability, adhesiveness, and conductivity, which enable them to be used in the manufacturing of drug/cell delivery vehicles, glues, electronic devices, and so on. MAIN BODY: This review will focus on the synthesis and applications of self-healing hydrogels. Their repair mechanisms and potential applications in pharmaceutical, biomedical, and other areas will be introduced. CONCLUSION: Self-healing hydrogels are used in various fields because of their ability to recover. The prospect of self-healing hydrogels is promising, and they may be further developed for various applications.

Curcumin has immunomodulatory effects on RANKL-stimulated osteoclastogenesis in vitro and titanium nanoparticle-induced bone loss in vivo.

Wear particle-stimulated inflammatory bone destruction and the consequent aseptic loosening remain the primary causes of artificial prosthesis failure and revision. Previous studies have demonstrated that curcumin has a protective effect on bone disorders and inflammatory diseases and can ameliorate polymethylmethacrylate-induced osteolysis in vivo. However, the effect on immunomodulation and the definitive mechanism by which curcumin reduces the receptor activators of nuclear factor-kappa B ligand (RANKL)-stimulated osteoclast formation and prevents the activation of osteoclastic signalling pathways are unclear. In this work, the immunomodulation effect and anti-osteoclastogenesis capacities exerted by curcumin on titanium nanoparticle-stimulated macrophage polarization and on RANKL-mediated osteoclast activation and differentiation in osteoclastic precursor cells in vitro were investigated. As expected, curcumin inhibited RANKL-stimulated osteoclast maturation and formation and had an immunomodulatory effect on macrophage polarization in vitro. Furthermore, studies aimed to identify the potential molecular and cellular mechanisms revealed that this protective effect of curcumin on osteoclastogenesis occurred through the amelioration of the activation of Akt/NF-κB/NFATc1 pathways. Additionally, an in vivo mouse calvarial bone destruction model further confirmed that curcumin ameliorated the severity of titanium nanoparticle-stimulated bone loss and destruction. Our results conclusively indicated that curcumin, a major biologic component of Curcuma longa with anti-inflammatory and immunomodulatory properties, may serve as a potential therapeutic agent for osteoclastic diseases.

Puerarin Exerts Protective Effects on Wear Particle-Induced Inflammatory Osteolysis.

Wear particle-stimulated inflammatory bone destruction and the consequent aseptic loosening remain major postoperative problems for artificial joints. Studies have indicated that puerarin promotes osteogenesis and alleviates lipopolysaccharide-induced osteoclastogenesis in vitro. However, the underlying molecular mechanism by which puerarin interacts with receptor activator of nuclear factor kappa-B ligand (RANKL)-mediated osteoclast formation in vitro and wear particle-stimulated osteolysis in vivo has not been reported. In this work, the protective effects exerted by puerarin on titanium particle-stimulated bone destruction in vivo and on RANKL-induced osteoclast activation in osteoclastic precursor cells in vitro were investigated. As expected, puerarin significantly inhibited wear particle-mediated bone resorption and proinflammatory cytokine productions in a calvarial resorption model. Additionally, puerarin inhibited RANKL-induced osteoclast activation, bone resorption ability, and F-actin ring formation in vitro as puerarin concentration increased. Furthermore, mechanistic investigation indicated that reduced RANKL-stimulated MEK/ERK/NFATc1 signaling cascades might regulate the protective effect of puerarin. Conclusively, these results indicate that puerarin, a type of polyphenol, might serve as a protective agent to prevent osteoclast-related osteolytic diseases.

A surface-engineered polyetheretherketone biomaterial implant with direct and immunoregulatory antibacterial activity against methicillin-resistant Staphylococcus aureus.

Metal ions or nanoparticles are believed to be promising additives in developing antibacterial biomaterials, owing to possessing favorable bactericidal effects against antibiotic-resistant bacteria. However, the immunomodulatory antibacterial activity of metal ions has seldom been reported. Herein, a porous microstructure designed to trap methicillin-resistant Staphylococcus aureus (MRSA) is fabricated on polyetheretherketone biomaterial surface through sulfonation (SPEEK), following which copper (Cu) nanoparticles, which can kill the trapped MRSA, are immobilized on SPEEK surface using a customized magnetron sputtering technique. In vitro antibacterial and immunological experiments indicate that the Cu-incorporated SPEEK can exert a desirable bactericidal effect against MRSA through the combination of "trap killing" and "contact killing" actions; meanwhile, macrophages cultured on the Cu-incorporated SPEEK can be activated and polarized to a pro-inflammatory phenotype along with improved phagocytic ability on the MRSA. Further in vivo implant-associated infection models evidence the superior antibacterial activity of the Cu-incorporated SPEEK. These results demonstrate multimodal antibacterial actions of the Cu-incorporated SPEEK, which is capable of imposing direct antibacterial and indirect immunomodulatory antibacterial effects simultaneously, in order to prevent and cure MRSA infection. It is believed that this study may shed light on developing novel biomaterial implants that combine antibacterial and immunomodulatory functions.

Alendronate stimulates osteoprotegerin expression in fibroblasts from periprosthetic membrane.

PURPOSE: Aseptic loosening of an implant after total joint arthroplasty is still a major complication that results from periprosthetic osteolysis. Fibroblasts in the interface membrane express receptor activator of nuclear factor kappa B ligand (RANKL) and stimulate osteoclast formation. Studies demonstrate that through the control of osteoclastic bone loss bisphosphonates inhibit wear particle-induced bone resorption around total hip arthroplasty. The majority of bisphosphonates studies have focused on their effects on osteoblasts and osteoclasts. Little attention has been paid to their action on fibroblasts. METHODS: We isolated fibroblasts from the interface membrane that was obtained when revision hip arthroplasty was performed because of aseptic loosening. Fibroblasts were stimulated with alendronate. RANKL and osteoprotegerin (OPG) assays were performed using enzyme-linked immunosorbent assay kit and real time Reverse Transcription- Polymerase Chain Reaction (RT-PCR). RESULTS: We found that alendronate stimulated OPG mRNA and protein expression in a time and dose dependent manner. By contrast, alendronate did not affect RANKL expression. CONCLUSIONS: The results indicate that alendronate modulated OPG production by fibroblasts from periprosthetic membrane, which may prove helpful for the inhibition of bone loss during aseptic loosening following total joint arthroplasty.

Repair of osteochondral defects by mosaicplasty and allogeneic BMSCs transplantation.

OBJECTIVE: To investigate the feasibility and efficacy of repairing osteochondral defects with mosaicplasty and allogeneic bone marrow mesenchymal stem cells (BMSCs) transplantation. METHODS: BMSCs were harvested from rabbits and maintained in vitro. Cells of third passage were mixed with pluronic F-127. Osteochondral defect animal model was established in rabbits and then this defect was treated with autologous osteochondral grafts with or without BMSCs above mentioned. In control group, pure pluronic F-127 was filled in the defect. Histological and immunohistological examinations were performed for the evaluation of therapeutic effectiveness. RESULTS: Autologous osteochondral grafts in both groups were not loose, prolapsed and depressed. In BMSCs group, the tissues in the "death space" became hyaline cartilage. The arrangement of chondrocytes was regular. At 4, 8, 12 and 16 weeks, O'Driscoll and Keeley and Salter score were 14.00±1.00, 16.75±1.71, 18.00±0.82 and 20.50±1.29 in BMSCs group, which were significantly higher than those in control group (7.67±0.58, 8.00±0.82, 8.50±0.58 and 9.00±0.82, respectively). There were significant differences among different treatments (F=584.028, P=0.000), but the score was comparable between right defect and left defect (F=0.028, P=0.890). In addition, significant difference was also observed at different time points (F=18.364, P=0.000), but there was no interaction between time and treatment (F=6.939, P=0.015). Moreover, interactions among other factors were also not observed. CONCLUSION: Mosaicplasty and BMSC transplantation are effective to repair the osteochondral defects and integrate the "death space", achieving a better therapeutic efficacy. Thus, this combined therapy may become an effective strategy for the therapy of osteochondral defects.

Substance P enhanced titanium particles-induced RANKL expression in fibroblasts from periprosthetic membrane.

Aseptic loosening remains the primary cause of failure in total joint arthroplasty. Implant-derived particles are thought to be a main cause of osteolysis that leads to the failure. Substance P (SP) immunoreactive nerve fibers have been detected in the periprosthetic membrane of aseptic loose hip prostheses. We isolated fibroblasts from periprosthetic membrane. Fibroblasts were examined by real-time RT-PCR and enzyme-linked immunosorbent assay for expression of the receptor activator of nuclear factor kappa B ligand (RANKL), osteoprotegerin (OPG), cyclooxygenase (COX)-1, and COX-2. Experiments were performed in the presence and absence of titanium particles, SP and NS-398 (a selective COX-2 inhibitor). Titanium particles or SP stimulated RANKL and COX-2 expression in fibroblasts, whereas NS-398 inhibited RANKL production, suggesting a COX-2-mediated event. Moreover, SP enhanced COX-2 and RANKL expression by titanium particles-stimulated fibroblasts. Thus, SP and titanium particles acted synergistically to increase RANKL expression.

High levels of substance P and CGRP in pseudosynovial fluid from patients with aseptic loosening of their hip prosthesis.

BACKGROUND: Aseptic loosening is the most important complication after total hip arthroplasty (THA). The nervous system has been implicated in the etiology and pathogenesis of joint diseases. METHODS: We compared levels of substance P (SP) and calcitonin gene-related peptide (CGRP) in pseudosynovial fluid from patients with aseptic loosening after THA with those in synovial fluid from patients undergoing primary THA for osteoarthritis, who served as controls. Levels of SP and CGRP were measured using an enzyme immunoassay. RESULTS: We found that SP and CGRP levels were significantly higher in the pseudosynovial fluid of loose artificial joints than in the synovial fluid of controls. INTERPRETATION: SP and CGRP may have a role in aseptic loosening.

Substance P stimulates production of interleukin 1beta and tumor necrosis factor alpha in fibroblasts from hip periprosthetic membrane.

Aseptic loosening remains the primary cause of failure in total joint arthroplasty. Substance P (SP)-immunoreactive nerve fibers have been detected in the pseudomembrane and pseudocapsular tissues of aseptic loose hip prostheses, suggesting that SP might be involved in the process of aseptic loosening. We isolated fibroblasts from periprosthetic membrane at the time of revision hip arthroplasty performed because of aseptic loosening. Fibroblasts were incubated in the presence of various concentrations of SP, and the levels of interleukin 1beta, and tumor necrosis factor alpha in the media were determined using enzyme-linked immunosorbent assay kit. We found that the levels of interleukin 1beta and tumor necrosis factor alpha increased in a time- and concentration-dependent manner. Our results suggested that SP might be involved in the pathogenesis of aseptic loosening.

Substance P augments PGE2 and IL-6 production in titanium particles-stimulated fibroblasts from hip periprosthetic membrane.

Aseptic loosening remains the primary cause of failure in total joint arthroplasty. Implant-derived particles are thought to be a main cause of osteolysis that leads to failure of total joint arthroplasty. The nervous system has been implicated in the etiology and pathogenesis of joint diseases. Substance P (SP) immunoreactive nerve fibers have been detected in the pseudomembrane and pseudocapsular tissues of aseptic loose hip prostheses, suggesting that SP might be involved in the process of aseptic loosening. Fibroblasts are abundant in periprosthetic membrane. Neuropeptides are able to modulate cytokine production by fibroblasts. In this study, we isolated fibroblasts from periprosthetic membrane at the time of revision hip arthroplasty performed because of aseptic loosening. Fibroblasts were stimulated with titanium (Ti) particles or SP. Prostaglandin (PG) E2 and interleukin-6 (IL-6) assays were performed using enzyme-linked immunosorbent assay kit. PGE2 and IL-6 secretion by fibroblasts have been significantly increased in the presence of Ti particles or SP. Moreover SP caused significant increase in PGE2 and IL-6 production by Ti particles-stimulated fibroblasts. Thus, SP and Ti particles acted synergistically to increase PGE2 and IL-6 secretion in fibroblasts from periprosthetic membrane.