Resveratrol Protects against Titanium Particle-Induced Aseptic Loosening Through Reduction of Oxidative Stress and Inactivation of NF-κB

Sandblasted/Acid-Etched Titanium Surface Modified with Calcium Phytate Enhances Bone Regeneration in a High-Glucose Microenvironment by Regulating Reactive Oxygen Species and Cell Senescence

Hyperglycemia in patients with diabetes affect osteoblast function, leading to abnormal bone metabolism and implant failure. Adequate bone volume surrounding an implant is essential for osseointegration, which can be improved by implant surface modifications. In this study, titanium surfaces were hydrothermally treated with a mixture of phytic acid (PA) and calcium hydroxide to produce a calcium-decorated surface. The control group comprised pure titanium with a sandblasted/acid-etched (SLA) surface. The elemental composition, hydrophilicity, surface roughness, and morphology of the titanium surfaces were examined. Evaluation of in vitro osteogenic differentiation ability in a high-glucose environment using alkaline phosphatase (ALP) staining, ALP activity assays, Alizarin Red S staining, quantitative reverse transcription-polymerase chain reaction (qRT-PCR), and immunofluorescence staining revealed that Ca-PA-modified SLA titanium surfaces can promote osteogenic differentiation of human bone marrow mesenchymal stem cells (hBMSCs). Evaluation of oxidative stress and aging using reactive oxygen species (ROS), malondialdehyde (MDA), superoxide dismutase (SOD), and β-galactosidase staining revealed that Ca-PA-modified SLA titanium surfaces can reduce ROS production and ameliorate oxidative stress damage in hBMSCs. In vivo assessment of osteogenesis in a diabetic rat model revealed that Ca-PA coating promotes peri-implant osseointegration. Ca-PA-modified SLA titanium surface is a candidate for improving implant osseointegration in patients with diabetes.

Carboxymethyl chitosan regulates oxidative stress and decreases the expression levels of tumor necrosis factor α in macrophages induced by wear particles

The aim of the present study was to determine the effects of carboxymethyl chitosan (CMC) on titanium particles-induced oxidative stress in mouse RAW264.7 macrophages. The mouse RAW264.7 macrophages were divided into four groups: (i) the control group; (ii) the CMC group received stimulation of CMC for 4 h; (iii) the titanium particles group received stimulation of titanium particles for 12 h; and (iv) the CMC group received pre-stimulation of CMC hydrogels for 4 h followed by treatment of titanium particles for 12 h. Afterwards, reactive oxygen species (ROS) level in the cells was measured by flow cytometry. A spectrophotometer was used to measure the activities of oxidases and antioxidant enzymes. Fluorescence quantitative PCR was performed to analyze mRNA levels of enzymes and tumor necrosis factor α (TNF-α). ELISA was used to detect the mass concentration of TNF-α after indicated treatment. CMC effectively suppressed titanium particles-induced oxidative stress in RAW264.7 cells, as evidenced by the decrease in intracellular ROS level, the transcription of oxidases, and TNF-α concentration as well as the increase in the transcription of antioxidant enzymes. CMC exerts a protective impact against wear particles-induced oxidative stress and reduces the release of TNF-α in RAW264.7 cells.

Reactive Oxygen Species Scavenging Nanomedicine for the Treatment of Ischemic Heart Disease

Ischemic heart disease (IHD) is the leading cause of disability and mortality worldwide. Reactive oxygen species (ROS) have been shown to play key roles in the progression of diabetes, hypertension, and hypercholesterolemia, which are independent risk factors that lead to atherosclerosis and the development of IHD. Engineered biomaterial-based nanomedicines are under extensive investigation and exploration, serving as smart and multifunctional nanocarriers for synergistic therapeutic effect. Capitalizing on cell/molecule-targeting drug delivery, nanomedicines present enhanced specificity and safety with favorable pharmacokinetics and pharmacodynamics. Herein, the roles of ROS in both IHD and its risk factors are discussed, highlighting cardiovascular medications that have antioxidant properties, and summarizing the advantages, properties, and recent achievements of nanomedicines that have ROS scavenging capacity for the treatment of diabetes, hypertension, hypercholesterolemia, atherosclerosis, ischemia/reperfusion, and myocardial infarction. Finally, the current challenges of nanomedicines for ROS-scavenging treatment of IHD and possible future directions are discussed from a clinical perspective.

NRF2 is a critical regulator and therapeutic target of metal implant particle-incurred bone damage

Aseptic metal implant loosening due to wear particle-induced bone damage is a major complication of total joint arthroplasty often leading to revision surgery, of which the key regulators mediating the processes are not clearly defined. Here we reported that in a mouse model of calvarial osteolysis, titanium particles (TiPs) and cobalt-chromium-molybdenum particles induced severe osteolysis accompanied by marked suppression of a master redox transcriptional factor NRF2 (Nuclear factor erythroid derived 2-related factor 2). Nfe2l2 knockout mice treated with TiPs developed worse osteolytic alterations compared with wild-type mice. On the contrary, NRF2 restoration by an NRF2 agonist TBHQ (tert-butylhydroquinone) effectively alleviated the osteolysis and the abnormal expression of NRF2 downstream antioxidant enzymes, inflammatory cytokines and osteogenic factors. Further, TiPs induced adverse osteoblastogenesis and osteoclastogenesis in cultured bone cells, which were substantially blocked by TBHQ in an NRF2 inhibition-sensitive manner. Consistently, the osteoprotective effects of TBHQ observed in wild-type mice were largely limited in Nfe2l2 knockout mice. Collectively, our data suggest that NRF2 suppression is a critical causal event of metal wear particle-incurred osteolysis, and the strategies reinstating NRF2 are effective to lessen the bone damage and potentially reduce the incidence of metal implant loosening.

Cyclic Polypeptide D7 Protects Bone Marrow Mesenchymal Cells and Promotes Chondrogenesis during Osteonecrosis of the Femoral Head via Growth Differentiation Factor 15-Mediated Redox Signaling

Osteonecrosis of the femoral head (ONFH) is a debilitating disease that is closely associated with the clinical application of high-dose glucocorticoids. Elevated oxidative stress contributes to the pathophysiological changes observed in ONFH. The lack of effective treatments besides surgical intervention highlights the importance of finding novel therapeutics. Our previous studies demonstrated that D7, a cyclic polypeptide, enhances the adhesion, expansion, and proliferation of bone marrow mesenchymal stem cells (BMSCs). Therefore, in this study, we investigated the therapeutic effects of D7 against ONFH in BMSCs and evaluated the underlying mechanisms. First, we screened for ONFH risk factors. Then, we applied D7 treatment to steroid-induced ONFH (SONFH) in an in vitro model produced by dexamethasone (DEX) to further elucidate the underlying mechanisms. We found negative correlations among oxidative stress marker expression, growth differentiation factor 15 (GDF15) levels, and ONFH. Furthermore, we demonstrated that DEX inhibited the proliferation and induced apoptosis of BMSCs by suppressing GDF15/AKT/mammalian target of rapamycin (mTOR) signaling. D7 alleviated DEX-induced BMSCs injury and restored the chondrogenic function of BMSCs by activating GDF15/AKT/mTOR signaling. In addition, DEX-induced excessive reactive oxygen species (ROS) generation was an upstream trigger of GDF15-mediated signaling, and D7 ameliorated this DEX-induced redox imbalance by restoring the expression of antioxidants, including superoxide dismutase (SOD) 1, SOD2, and catalase, via regulation of GDF15 expression. In conclusion, our findings revealed the potential therapeutic effects of D7 in SONFH and showed that this protective function may be mediated via inhibition of DEX-induced ROS and activation of GDF15/AKT/mTOR signaling, thereby providing insights into the potential applications of D7 in SONFH treatment.

Resveratrol-loaded titania nanotube coatings promote osteogenesis and inhibit inflammation through reducing the reactive oxygen species production via regulation of NF-κB signaling pathway

Although titanium and its alloys are widely used in bone surgeries, the implantation failures caused by sterile inflammation still occur. The excessive reactive oxygen species (ROS) in the peri-implant region are considered to cause inflammation and impede the osseointegration of titanium implants. In this study, a coating of resveratrol-loaded titania nanotube (TNT-Res) for eliminating ROS was fabricated on titanium surface through electrochemical anodization and following surface adsorption of resveratrol. The resveratrol concentration of released from TNT-Res coating was controlled by modulating the loading amount. The ROS production in macrophage cell lineage RAW 264.7 and bone mesenchymal stem cells (BMSCs) were significantly decreased when cultured on TNT-Res coatings. The pro-inflammatory factors, including tumor necrosis factor α (TNF-α) and interleukin 1β (IL-1β), and NO produced by RAW 264.7 cells were reduced when cells were cultured on TNT-Res coatings. These results proved that the TNT-Res coating can effectively eliminate ROS and inhibit inflammation. Moreover, the osteogenic indicators, including alkaline phosphatase (ALP) production, extracellular calcium deposition, and osteogenesis-related gene expression, including collagen І (Col-І), osteocalcin (OCN), osteopontin (OPN), and runt-related transcription factor 2 (Runx2), were significantly promoted for TNT-Res groups, which demonstrated that the TNT-Res coating can enhance the osteogenic differentiation of BMSCs. Additionally, the phosphorylation of nuclear factor κ-B (NF-κB) were down-regulated both in RAW 264.7 cells and BMSCs, which indicated that the TNT-Res coating could inhibit inflammation and promote osteogenesis by inhibiting the activation of NF-κB signaling pathway. The TNT-Res coating could be an effective implant surface for improving osseointegration ability of titanium implants.

Selenomethionine protects oxidative-stress-damaged bone-marrow-derived mesenchymal stem cells via an antioxidant effect and the PTEN/PI3K/AKT pathway

Dental implant surgery is currently a routine therapy for the repair of missing dentition or dentition defects. Both clinical and basic research have elucidated that oxidative stress caused by the accumulation of reactive oxygen species (ROS) for various reasons impairs the process of osteointegration after dental implantation. Therefore, the osteogenic micro-environment must be ameliorated to decrease the damage caused by oxidative stress. Selenomethionine (SEMET) has been reported to play an important role in alleviating oxidative stress and accelerating cell viability and growth. However, it remains unclear whether it exerts protective effects on bone-marrow-derived mesenchymal stem cells (BMSCs) under oxidative stress. In this study, we explored the influence of selenomethionine on the viability and osteogenic differentiation of BMSCs under oxidative stress and the underlying mechanisms. Results showed that 1 μM selenomethionine was the optimum concentration for BMSCs under H₂O₂ stimulation. H₂O₂-induced oxidative stress suppressed the viability and osteogenic differentiation of BMSCs, manifested by the increases in ROS production and cell apoptosis rates, and by the decrease of osteogenic differentiation-related markers. Notably, the aforementioned oxidative damage and osteogenic dysfunction induced by H₂O₂ were rescued by selenomethionine. Furthermore, we found that the PTEN expression level was suppressed and its downstream PI3K/AKT pathway was activated by selenomethionine. However, when PTEN was stimulated, the PI3K/AKT pathway was down-regulated, and the protective effects of selenomethionine on BMSC osteogenic differentiation diminished, while the inhibition of PTEN up-regulated the protective effects of selenomethionine. Together, these results revealed that selenomethionine could attenuate H₂O₂-induced BMSC dysfunction through an antioxidant effect, modulated via the PTEN/PI3K/AKT pathway, suggesting that selenomethionine is a promising antioxidant candidate for reducing oxidative stress during the process of dental implant osteointegration.

Effect of Oxidative Stress on Bone Remodeling in Periprosthetic Osteolysis

The success of implant performance and arthroplasty is based on several factors, including oxidative stress-induced osteolysis. Oxidative stress is a key factor of the inflammatory response. Implant biomaterials can release wear particles which may elicit adverse reactions in patients, such as local inflammatory response leading to tissue damage, which eventually results in loosening of the implant. Wear debris undergo phagocytosis by macrophages, inducing a low-grade chronic inflammation and reactive oxygen species (ROS) production. In addition, ROS can also be directly produced by prosthetic biomaterial oxidation. Overall, ROS amplify the inflammatory response and stimulate both RANKL-induced osteoclastogenesis and osteoblast apoptosis, resulting in bone resorption, leading to periprosthetic osteolysis. Therefore, a growing understanding of the mechanism of oxidative stress-induced periprosthetic osteolysis and anti-oxidant strategies of implant design as well as the addition of anti-oxidant agents will help to improve implants’ performances and therapeutic approaches.

The TiO2-μ implant residual is more toxic than the Al2O3-n implant residual via blocking LAP and inducing macrophage polarization

Medical device residuals cause harmful effects and diseases in the human body, such as Particle Disease (PD), but the biological interaction of different types of particles is unclear. In this study, after a biological interaction screen between different particles, we aimed to explore the mechanism of the biological interaction between different types of particles, and the effect of a proteasome inhibitor on PD. Our studies showed that the titanium oxide microscale particle (Ti-μ) was more toxic than the aluminum oxide nanoscale particle (Al-n). Al-n activated LAP, attenuated the macrophage M1 polarization, inhibited the activator of the NF-κB pathway, and blocked the secretion of inflammatory factors and apoptosis in vitro, and also prevented the inflammation tissue disorder and aseptic loosening in vivo induced by Ti-μ. What is more, Bortezomib blocked apoptosis, secretion of inflammatory factors and the activation of the NF-κB pathway induced by TiO2 micro particles. Al-n-induced autophagy could play the function in the efficient clearance of dying cells by phagocytosis, and serves in dampening M1 polarization-related pro-inflammatory responses. While the Ti alloy medical implant and devices are applied worldwide, the toxicity of Ti-μ and its interaction with Al-n could be considered in the implant design, and Bortezomib was a potential therapeutic for PD.

Reactive oxygen/nitrogen species (ROS/RNS) and oxidative stress in arthroplasty

The interplay between implant design, biomaterial characteristics, and the local microenvironment adjacent to the implant is of utmost importance for implant performance and success of the joint replacement surgery. Reactive oxygen and nitrogen species (ROS/RNS) are among the various factors affecting the host as well as the implant components. Excessive formation of ROS and RNS can lead to oxidative stress, a condition that is known to damage cells and tissues and also to affect signaling pathways. It may further compromise implant longevity by accelerating implant degradation, primarily through activation of inflammatory cells. In addition, wear products of metallic, ceramic, polyethylene, or bone cement origin may also generate oxidative stress themselves. This review outlines the generation of free radicals and oxidative stress in arthroplasty and provides a conceptual framework on its implications for soft tissue remodeling and bone resorption (osteolysis) as well as implant longevity. Key findings derived from cell culture studies, animal models, and patients' samples are presented. Strategies to control oxidative stress by implant design and antioxidants are explored and areas of controversy and challenges are highlighted. Finally, directions for future research are identified. A better understanding of the host-implant interplay and the role of free radicals and oxidative stress will help to evaluate therapeutic approaches and will ultimately improve implant performance in arthroplasty.

Diagnosis and management of implant debris-associated inflammation

Introduction: Total joint replacement is one of the most common, safe, and efficacious operations in all of surgery. However, one major long-standing and unresolved issue is the adverse biological reaction to byproducts of wear from the bearing surfaces and modular articulations. These inflammatory reactions are mediated by the innate and adaptive immune systems.Areas covered: We review the etiology and pathophysiology of implant debris-associated inflammation, the clinical presentation and detailed work-up of these cases, and the principles and outcomes of non-operative and operative management. Furthermore, we suggest future strategies for prevention and novel treatments of implant-related adverse biological reactions.Expert opinion: The generation of byproducts from joint replacements is inevitable, due to repetitive loading of the implants. A clear understanding of the relevant biological principles, clinical presentations, investigative measures and treatments for implant-associated inflammatory reactions and periprosthetic osteolysis will help identify and treat patients with this issue earlier and more effectively. Although progressive implant-associated osteolysis is currently a condition that is treated surgically, with further research, it is hoped that non-operative biological interventions could prolong the lifetime of joint replacements that are otherwise functional and still salvageable.

Tocotrienols Regulate Bone Loss through Suppression on Osteoclast Differentiation and Activity: A Systematic Review

Background

There are accumulating studies reporting that vitamin E in general exhibits bone protective effects. This systematic review, however discusses the effects of a group of vitamin E isomers, tocotrienols in preventing bone loss through osteoclast differentiation and activity suppression.

Objective

This review is aimed to discuss the literature reporting the effects of tocotrienols on osteoclasts, the cells specialized for resorbing bone.

Results

Out of the total 22 studies from the literature search, only 11 of them were identified as relevant, which comprised of eight animal studies, two in vitro studies and only one combination of both. The in vivo studies indicated that tocotrienols improve the bone health and reduce bone loss via inhibition of osteoclast formation and resorption activity, which could be through regulation of RANKL and OPG expression as seen from their levels in the sera. This is well supported by data from the in vitro studies demonstrating the suppression of osteoclast formation and resorption activity following treatment with tocotrienol isomers.

Conclusion

Thus, tocotrienols are suggested to be potential antioxidants for prevention and treatment of bone-related diseases characterized by increased bone loss.

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.

Alterations in oxidative responses and post-translational modification caused by p,p´-DDE in Mus spretus testes reveal Cys oxidation status in proteins related to cell-redox homeostasis and male fertility

The major derivate of DDT, 1,1-dichloro-2,2-bis (p-chlorophenyl) ethylene (p,p´-DDE), is a persistent pollutant previously associated with oxidative stress. Additionally, p,p´-DDE has been linked to several metabolic alterations related to sexual function in rodents. In this study, we analysed the effects of a non-lethal p,p´-DDE dose to Mus spretus mice in testes, focusing on oxidative damage to biomolecules, defence mechanisms against oxidative stress and post-translational protein modifications. No increase in lipid or DNA oxidation was observed, although antioxidative enzymatic defences and redox status of glutathione were altered in several ways. Global protein carbonylation and phosphorylation were significantly reduced in testes from p,p´-DDE-exposed mice; however, the total redox state of Cys thiols did not exhibit a defined pattern. We analysed the reversible redox state of specific Cys residues in detail with differential isotopic labelling and a shotgun labelling-based MS/MS proteomic approach for identification and quantification of altered peptides. Our results show that Cys residues are significantly affected by p,p´-DDE in several proteins related to oxidative stress and/or male fertility, particularly those participating in fertilization, sperm capacitation and blood coagulation. These molecular changes could explain the sexual abnormalities previously described in p,p´-DDE exposed organisms.

Dysregulated expression of antioxidant enzymes in polyethylene particle-induced periprosthetic inflammation and osteolysis

Small wear particles (0.1–10 μm) in total joint replacement are generally considered as the major causative agent leading to periprosthetic inflammation and osteolysis. However, little is known about the roles of larger wear particles (10–100 μm) in periprosthetic inflammation and osteolysis. Additionally, although ample studies demonstrated that increased oxidative stress is critically involved in particle-induced inflammation and osteolysis, detailed changes in antioxidant enzymes expression in the disease development remain largely unclear. Herein, we used a rat knee prosthesis model to assess effects of polyethylene (PE) particles (20–60 μm) on the levels of oxidative stress markers such as malondialdehyde (MDA) and total antioxidant capacity (TAC) in blood plasma, and on the expression profiles of antioxidant enzymes in knee joint tissues. In combination with a forced-exercise intervention for all surgical rats, we found that the rat groups treated with both artificial joint and PE particles exhibited higher MDA levels and lower TAC levels, together with lower levels of physical activity and higher levels of inflammatory markers, than the sham group and the groups receiving artificial joint or PE particles alone at weeks 20–24 post-operatively. Dose-response relationships between the exposure to PE particles and the induction of oxidative stress and inflammation were also observed in the artificial joint/PE groups. Under such conditions, we unexpectedly found that most of antioxidant enzymes displayed pronounced up-regulation, with concomitant induction of inflammatory and osteoclast-inducing factors (including IL-1β, NF-κB and RANKL), in the artificial joint/PE groups as compared to the sham, artificial joint only, or PE only group. Only a few antioxidant enzymes including SOD2 and GPx2 showed down-regulation. Collectively, our findings demonstrate that implantation of artificial joint along with large PE particles synergistically trigger the induction of oxidative stress; however, down-regulation of many antioxidant enzymes may not necessarily occur during the disease development.

Resveratrol provides benefits in mice with type II diabetes-induced chronic renal failure through AMPK signaling pathway

Type II diabetes-induced ischemic injuries are known to lead to the rapid degeneration of the kidneys as a result of chronic renal failure. Chronic renal failure is a condition, which typically manifests with symptoms including cardiovascular system and left ventricular hypertrophy, atherosclerosis as well as arterial and aortic stiffness. Resveratrol is a multifunctional compound that has been reported to produce beneficial outcomes for patients with type-II diabetes due to prevention of oxidative stress and apoptosis. However, the beneficial effects of resveratrol in chronic renal failure and the underlying mechanisms have remained to be fully elucidated. The present study investigated the therapeutic effects of resveratrol in mice with chronic renal failure induced by type-II diabetes and assessed the mechanism of action. Oxidative stress, apoptosis and adenosine monophosphate-activated protein kinase (AMPK) in the renal cells of the model mice were assessed. Changes in inflammatory factors renal cells from experimental mice as well as insulin resistance were also analyzed. Morphological changes and immunocytes in renal cells were determined by immunostaining. The results demonstrated that resveratrol treatment decreased the apoptotic rate of renal cells from experimental mice. Oxidative stress also improved in renal cells, as indicated by inhibition of superoxide dismutase and reduced glutathione and 4-hydroxy-2-nonenal levels. In addition, insulin resistance was improved after an 8-week treatment with resveratrol. Inflammatory factors were decreased and factors promoting kidney function were increased after resveratrol treatment. Furthermore, morphological changes were observed to be ameliorated, indicating the therapeutic efficacy of resveratrol. In addition, immunocyte precipitation in renal cells was markedly decreased in resveratrol-treated mice. Importantly, the AMPK signaling pathway was found to be involved in the beneficial effect of resveratrol on the model mice. In conclusion, the present study suggested that resveratrol may be an ideal agent for the treatment of chronic renal failure induced by type-II diabetes through regulation of the AMPK signaling pathway, which should be further investigated in clinical trials.

LncRNA KCNQ1OT1 promotes osteogenic differentiation to relieve osteolysis via Wnt/β-catenin activation

Background

Resveratrol (RSV) has been reported to stimulate osteoblast differentiation in which Wnt/β-catenin signaling pathway played a crucial role. However, whether and how RSV activated Wnt/β-catenin pathway in osteogenic differentiation still remained elusive.

Methods

In vivo polymethylmethacrylate (PMMA) particle-induced osteolysis (PIO) mouse model and in vitro PMMA particle-stimulated mouse mesenchymal stem cells (mMSCs) experiments were established. Relative expression levels of lncRNA KCNQ1OT1, β-catenin, Runx2, Osterix and osteocalcin were determined using quantitative Real-Time PCR. Western blotting was used to measure β-catenin protein expression. In addition, the alkaline phosphatase activity and mineral deposition level using alizarin red S staining were performed to examine osteogenic differentiation status. The interaction between KCNQ1OT1 and β-catenin was confirmed by RNA pull down assay.

Results

RSV significantly attenuated PIO in vivo and PMMA-particle inhibition of osteogenic differentiation of mMSCs. Moreover, KCNQ1OT1 exerted the similar function in mMSCs by regulating β-catenin. Further study demonstrated that RSV exerted its effect on osteoblastic differentiation by regulating KCNQ1OT1. Consequently, RSV alleviated PMMA-particle inhibition of osteoblastic differentiation via Wnt/β-catenin pathway activation in vivo and in vitro.

Conclusion

RSV accelerated osteoblast differentiation by regulating lncRNA KCNQ1OT1 via Wnt/β-catenin pathway activation, indicating the functional role of RSV in modulating osteogenesis.

Dosis Facit Sanitatem-Concentration-Dependent Effects of Resveratrol on Mitochondria

The naturally occurring polyphenol, resveratrol (RSV), is known for a broad range of actions. These include a positive impact on lifespan and health, but also pro-apoptotic anti-cancer properties. Interestingly, cell culture experiments have revealed a strong impact of RSV on mitochondrial function. The compound was demonstrated to affect mitochondrial respiration, structure and mass of mitochondria as well as mitochondrial membrane potential and, ultimately, mitochondria-associated cell death pathways. Notably, the mitochondrial effects of RSV show a very strict and remarkable concentration dependency: At low concentrations, RSV (<50 μM) fosters cellular antioxidant defense mechanisms, activates AMP-activated protein kinase (AMPK)- and sirtuin 1 (SIRT1)-linked pathways and enhances mitochondrial network formation. These mechanisms crucially contribute to the cytoprotective effects of RSV against toxins and disease-related damage, in vitro and in vivo. However, at higher concentrations, RSV (>50 μM) triggers changes in (sub-)cellular Ca²⁺ homeostasis, disruption of mitochondrial membrane potential and activation of caspases selectively yielding apoptotic cancer cell death, in vitro and in vivo. In this review, we discuss the promising therapeutic potential of RSV, which is most probably related to the compound’s concentration-dependent manipulation of mitochondrial function and structure.

Review: the potential impact of surface crystalline states of titanium for biomedical applications

In many biomedical applications, titanium forms an interface with tissues, which is crucial to ensure its long-term stability and safety. In order to exert control over this process, titanium implants have been treated with various methods that induce physicochemical changes at nano and microscales. In the past 20 years, most of the studies have been conducted to see the effect of topographical and physicochemical changes of titanium surface after surface treatments on cells behavior and bacteria adhesion. In this review, we will first briefly present some of these surface treatments either chemical or physical and we explain the biological responses to titanium with a specific focus on adverse immune reactions. More recently, a new trend has emerged in titanium surface science with a focus on the crystalline phase of titanium dioxide and the associated biological responses. In these recent studies, rutile and anatase are the major two polymorphs used for biomedical applications. In the second part of this review, we consider this emerging topic of the control of the crystalline phase of titanium and discuss its potential biological impacts. More in-depth analysis of treatment-related surface crystalline changes can significantly improve the control over titanium/host tissue interface and can result in considerable decreases in implant-related complications, which is currently a big burden on the healthcare system.

Resveratrol inhibits urban particulate matter-induced COX-2/PGE2 release in human fibroblast-like synoviocytes via the inhibition of activation of NADPH oxidase/ROS/NF-κB

Human fibroblast-like synoviocytes (FLSs) play a role in joint synovial inflammation in rheumatoid arthritis (RA). Some evidence indicates that particulate matter (PM) in air pollution could contribute to the progression of RA. However, more research is needed to clarify this relationship. Up-regulation of cyclooxygenase (COX)-2 and its metabolite prostaglandin E₂ (PGE₂) are implicated in various inflammatory diseases. Resveratrol, a polyphenol found mainly in grapes and red wine, has antioxidant and anti-inflammatory activities. In the present study, we demonstrated that resveratrol reduced PM-induced COX-2/PGE₂ expression in human FLSs, and attenuated PM-enhanced NADPH oxidase activity and ROS generation. In addition, PM induced Akt, ERK1/2, or p38 MAPK activation, which was inhibited by resveratrol. Finally, we demonstrated that PM enhanced NF-κB p65 phosphorylation and the NF-κB promoter activity, which were reduced by pretreatment with a ROS inhibitor or resveratrol. Thus, we concluded that resveratrol functions as a suppressor of PM-induced inflammatory signaling pathways by inhibiting COX-2/PGE₂ expression.

Gene Expression in Osteolysis: Review on the Identification of Altered Molecular Pathways in Preclinical and Clinical Studies

Aseptic loosening (AL) due to osteolysis is the primary cause of joint prosthesis failure. Currently, a second surgery is still the only available treatment for AL, with its associated drawbacks. The present review aims at identifying genes whose expression is altered in osteolysis, and that could be the target of new pharmacological treatments, with the goal of replacing surgery. This review also aims at identifying the molecular pathways altered by different wear particles. We reviewed preclinical and clinical studies from 2010 to 2016, analyzing gene expression of tissues or cells affected by osteolysis. A total of 32 in vitro, 16 in vivo and six clinical studies were included. These studies revealed that genes belonging to both inflammation and osteoclastogenesis pathways are mainly involved in osteolysis. More precisely, an increase in genes encoding for the following factors were observed: Interleukins 6 and 1β (IL16 and β), Tumor Necrosis Factor α (TNFα), nuclear factor kappa-light-chain-enhancer of activated B cells (NFκB), Nuclear factor of activated T-cells, cytoplasmic 1 (NFATC1), Cathepsin K (CATK) and Tartrate-resistant acid phosphatase (TRAP). Titanium (Ti) and Polyethylene (PE) were the most studied particles, showing that Ti up-regulated inflammation and osteoclastogenesis related genes, while PE up-regulated primarily osteoclastogenesis related genes.