Aims. Pellino1 (Peli1) has been reported to regulate various inflammatory diseases. This study aims to explore the role of Peli1 in the occurrence and development of osteoarthritis (OA), so as to find new targets for the treatment of OA. Methods. After inhibiting Peli1 expression in chondrocytes with small interfering RNA (siRNA), interleukin (IL)-1β was used to simulate inflammation, and OA-related indicators such as synthesis, decomposition, inflammation, and apoptosis were detected. Toll-like receptor (TLR) and nuclear factor-kappa B (NF-κB) signalling pathway were detected. After inhibiting the expression of Peli1 in
Aims. It has been established that mechanical stimulation benefits tendon-bone (T-B) healing, and
Aims. This study aimed to determine if
Osteoarthritis, the most common degenerative joint disease, significantly impairs life quality and labor capability of patients. Synovial inflammation, initiated by HMGB1 (High mobility group box 1)-induced activation of
Aseptic inflammation is the main factor causing aseptic loosening of artificial joints. Studies have shown that inflammatory cells can activate STING (stimulator of interferon genes, STING) after being stressed. This study aims to explore the specific mechanism of STING in aseptic loosening of artificial joints, and provide new strategies for disease prevention. Titanium particles with a diameter of 1.2-10 μm were prepared to stimulate
Aims. The use of 3D-printed titanium implant (DT) can effectively guide bone regeneration. DT triggers a continuous host immune reaction, including
As peri-prosthetic aseptic loosening is one of the main causes of implant failure, inhibiting wear particles induced
Aims. Tert-butylhydroquinone (tBHQ) has been identified as an inhibitor of oxidative stress-induced injury and apoptosis in human neural stem cells. However, the role of tBHQ in osteoarthritis (OA) is unclear. This study was carried out to investigate the role of tBHQ in OA. Methods. OA animal model was induced by destabilization of the medial meniscus (DMM). Different concentrations of tBHQ (25 and 50 mg/kg) were intraperitoneally injected in ten-week-old female mice. Chondrocytes were isolated from articular cartilage of mice and treated with 5 ng/ml lipopolysaccharide (LPS) or 10 ng/ml interleukin 1 beta (IL-1β) for 24 hours, and then treated with different concentrations of tBHQ (10, 20, and 40 μM) for 12 hours. The expression levels of malondialdehyde (MDA) and superoxide dismutase (SOD) in blood were measured. The expression levels of interleukin 6 (IL-6), IL-1β, and tumour necrosis factor alpha (TNF-α) leptin in plasma were measured using enzyme-linked immunoabsorbent assay (ELISA) kits. The expression of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) and mitogen-activated protein kinase (MAPK) signalling pathway proteins, and
Sarcopenia is an age-related geriatric syndrome which is associated with subsequent disability and morbidity. Currently there is no promising therapy approved for the treatment of sarcopenia. The receptor activator of nuclear factor NF-κB ligand (RANKL) and its receptor (RANK) are expressed in bone and skeletal muscle. Activation of the NF-κB pathway mainly inhibits myogenic differentiation, which leads to skeletal muscle dysfunction and loss. LYVE1 and CD206 positive
The Masquelet technique is a variable method for treating critical-sized bone defects, but there is a need to develop a technique for promoting bone regeneration. In recent studies of bone fracture healing promotion, macrophage-mesenchymal stem cell (MSC) cross-talk has drawn attention. This study aimed to investigate
Objectives. Up to 10% of fractures result in undesirable outcomes, for which female sex is a risk factor. Cellular sex differences have been implicated in these different healing processes. Better understanding of the mechanisms underlying bone healing and sex differences in this process is key to improved clinical outcomes. This study utilized a macrophage–mesenchymal stem cell (MSC) coculture system to determine: 1) the precise timing of proinflammatory (M1) to anti-inflammatory (M2)
Background. Mechanisms underlying implant failure remain incompletely described, though the presence of macrophage-mediated inflammatory reactions is well documented. Hypoxia has a critical role in many diseases and is known to be interdependent with inflammation. Metals used for joint replacements have also been reported to provoke hypoxia-like conditions. In view of this, we aim to investigate hypoxia-associated factors in aseptic loosening and osteoarthritis with a focus on
Human synovium harbours
Introduction. The combined incidence of anatomic (aTSA) and reverse total shoulder arthroplasties (rTSA) in the US is 90,000 per annum and rising. There has been little attention given to potential long-term complications due to periprosthetic tissue reactions to implant debris. The shoulder has been felt to be relatively immune to these complications due to lower acting loads compared to other joint arthroplasties. In this study, retrieved aTSAs and rTSAs were examined to determine the extent of implant damage and to characterize the nature of the corresponding periprosthetic tissue responses. Methods. TSA components and periprosthetic tissues were retrieved from 23 (eleven aTSA, twelve rTSA). Damage to the implants was characterized using light microscopy. Head/stem taper junction damage was graded 1–4 as minimal, mild, moderate or marked. Damage on polyethylene (PE) and metal bearing surfaces was graded 1–3 (mild, moderate, marked). H&E stained sections of periprosthetic soft tissues were evaluated for the extent and type of cellular response. A semi-quantitative system was used to score (1=rare to 4=marked) the overall number of particle-laden
All types of regenerative materials, including metal implants, porous scaffolds and cell-laden hydrogels, interact with the living tissue and cells. Such interaction is key to the settlement and regenerative outcomes of the biomaterials. Notably, the immune reactions from the host body crucially mediate the tissue-biomaterials interactions. Macrophages (as well as monocytes and neutrophils), traditionally best known as defenders, accumulate at the tissue-biomaterials interface and secrete abundant cytokines to create a microenvironment that benefits or inhibits regeneration. Because the phenotype of these cells is highly plastic in response to varying stimuli, it may be feasible to manipulate their activity at the interface and harness their power to mediate bone regeneration. Towards this goal, our team have been working on macrophage-driven bone regeneration in two aspects. First, targeting the abundant, glucan/mannan-recognising receptors on
It has been previously shown that Low-Magnitude High-Frequency Vibration (LMHFV) is able to enhance ovariectomy-induced osteoporotic fracture healing in rats. Fracture healing begins with the inflammatory stage, and all subsequent stages are regulated by the infiltration of immune cells such as
Although osteoarthritis (OA) is characterized by articular cartilage damage, synovial inflammation is a prominent feature contributing to disease progression. In addition to synovial tissue resident
It is reported that more than 10 million Japanese suffer from arthrosis. To cure these cartilage defects, total joint replacements, which are the most popular treatment methods for severe disease situation, have been operated as about two hundred thousand cases a year in Japan. Although the implants made of either ceramics, metals or plastics have high wear resistance quality, it becomes apparent that the endurance life of the artificial joints in considerable cases is limited by aseptic loosening to between 10–15 years. Here we focused on a poly(vinyl alcohol) (PVA) hydrogel as an artificial cartilage tissue to make an improvement of friction surface of the artificial joints. In this paper, we observed morphology of wear particles and assessed immune responses of wear particles from the hydrogel for confirming the validity of the gel as a biotribological material. We prepared 20 w/w% of PVA hydrogel by repeated freezing-thawing method. The number of the freezing-thawing cycles was five times. Polymerization degree and saponification degree of PVA (Kishida Chemical Co. Ltd., Japan) were 2000 and 98.4–99.8 mol%, respectively. To collect the wear particles of PVA hydrogel, we processed wear testing by using a purpose-build wear test machine of reciprocating pin-on-plate tribometer as shown in figure 1. We installed a Co-Cr-Mo ball of 26 mm in diameter as a stationary upper specimen and a PVA hydrogel plate of 2 mm in thickness as reciprocating lower specimen in a water bath. The lubricant was a distilled water containing eluted PVA which PVA-FT gel had been soaked in, filtered by 0.22 μm and autoclaved, subsequently. Siding speed was 50 mm/s and the total sliding distance was 3 km. We observed the wear particles which had been dried in a desiccator, by scanning electron microscope (SEM; SU8000, Hitachi High-Technologies). Additionally, to investigate the effect of the wear particles on response of phagocytosis of
Introduction. Periprosthetic joint infection (PJI) and particle-induced osteolysis are closely related to peri-implant local immunity and
Aseptic loosening and osteolysis around prosthetic joints are the principal causes of failure and consequent revision. During this process activated
Mechanical load is crucial to maintaining skeletal homeostasis, but the pathways involved in mecha-notransduction are still unclear. The OPG/RANK/ RANKL triumvirate has recently been implicated in bone homeostasis. These molecules, which are produced by the osteoblast (OPG and RANKL) and the
Particulate wear debris is associated with periprosthetic inflammation and loosening in total joint arthroplasty. We tested the effects of titanium alloy (Ti-alloy) and PMMA particles on monocyte/
The cellular mechanisms which account for the formation of osteoclasts and bone resorption associated with enlarging benign and malignant mesenchymal tumours of bone are uncertain. Osteoclasts are marrow-derived, multinucleated, bone-resorbing cells which express a
Periprosthetic osteolysis is a major cause of aseptic loosening in artificial joint replacement. It is assumed to occur in conjunction with the activation of
Macrophages and their fused products are commonly found at the polymethylmethacrylate cement-bone interface, but it is not known if they contribute directly to the osteolysis associated with loosening of the cemented prosthesis. We isolated mononuclear phagocytes from granulomas formed by subcutaneous implantation of polymethylmethacrylate into mice and incubated them on bone slices in which they formed resorption lacunae after co-culture for seven to 14 days with both marrow stromal cells and osteoblast-like cells (in the presence of 1 alpha,25-dihydroxyvitamin D3 and dexamethasone). Increased numbers of tartrate-resistant acid phosphatase-positive mononuclear and multinucleated cells formed in these cultures. Both in the presence and absence of stromal cells,
We exposed human
This study presents the use of precision surface machining on artificial joint bearing surfaces in order to inhibit
Although the response of
Summary Statement. Cross-talk between cells from immune and bone system might play a role in molecular regulation of subchondral bone sclerosis in osteoarthritis. Macrophages, B-lymphocytes and tartrate-resistant acid phosphatase activity are specifically increased in sclerotic subchondral bone of patients with knee osteoarthritis. Background. Recent investigations have provided substantial evidence that distinct molecular and morphological changes in subchondral bone tissue, most notably sclerosis, play an active and important role in the pathogenesis of OA. The cellular and molecular regulation of this pathological process remains poorly understood. Here, we investigated whether osteoimmunology, the reciprocal signaling between cells from the immune and bone system, is involved in OA subchondral bone sclerosis. Patients & Methods. Tibial plateaus and informed consent were obtained from patients undergoing total knee arthroplasty due to end-stage OA. Subchondral bone mineralization distribution was analyzed using computed tomography osteoabsoptiometry (CT-OAM) and standardised cryosections of low (non-sclerotic) and high (sclerotic) bone mineralization were prepared (n=18 each). Cartilage degeneration was graded in Safranin-O-stained sections using the Mankin scoring system. The presence of T-lymphocytes, B-cells and
An ultra-high molecular weight polyethylene (UHMWPE) is widely used as bearing material in artificial joints, however, UHMWPE wear particles are considered to be a major factor in long-term osteolysis and loosening of implants. The wear particles activate
Objectives. The aim of this study was to examine whether asymmetric loading
influences
Sterilisation by gamma irradiation in the presence of air causes free radicals generated in polyethylene (PE) to react with oxygen, which could lead to loss of physical properties and reduction in fatigue strength. Tissue retrieved from failed total hip replacements often has large quantities of particulate PE and most particles associated with peri-implant osteolysis are oxidised. Consequently, an understanding of the cellular responses of oxidised PE particles may lead to clarification of the pathogenesis of osteolysis and aseptic loosening. We have used the agarose system to demonstrate the differential effects of oxidised and non-oxidised PE particles on the release of proinflammatory products such as interleukin-1β (IL-1β), IL-6, and tumour necrosis factor-α (TNF-α) from monocytes/
An ultra-high molecular weight polyethylene (UHMWPE) is widely used as bearing material in artificial joints, however, UHMWPE wear particles are considered to be a major factor in long-term osteolysis and loosening of implants. The wear particles activate
Chronic inflammatory events have been associated to almost every chronic disease, including cardiovascular-, neurodegenerative- and autoimmune- diseases, cancer, and host-implant rejection. Given the toll of chronic inflammation in healthcare and socioeconomical costs developing strategies to resolve and control chronic states of inflammation remain a priority for the significant benefit of patients. Macrophages (Mφ) hold a central role both in the initiation and resolution of inflammatory events, assuming different functional profiles. The outstanding features of Mφ counting with the easy access to tissues, and the extended networking make Mφ excellent candidates for precision therapy. Moreover, sophisticated macrophage-oriented systems could offer innovative immune-regulatory alternatives to effectively regulate chronic environments that traditional pharmacological agents cannot provide. We propose magnetically assisted systems for balancing Mφ functions at the injury site. This platform combines polymers, inflammatory miRNA antagonists and magnetically responsive nanoparticles to stimulate Mφ functions towards pro-regenerative phenotypes. Strategies with magnetically assisted systems include contactless presentation of immune-modulatory molecules, cell internalization of regulatory agents for functional programming via magnetofection, and multiple payload delivery and release. Overall, Mφ-oriented systems stimulated pro-regenerative functions of Mφ supporting magnetically assisted theranostic nanoplatforms for precision therapies, envisioning safer and more effective control over the distribution of sensitive nanotherapeutics for the treatments of chronical inflammatory conditions.
RES Hub (Norte-01-0145-FEDER-022190).
We have investigated whether the particle-stimulated release of inflammatory cytokines from human primary
Particulate prosthetic materials are often studied by adding them to monocytic cells in vitro and measuring the release of cytokines as an indicator of their inflammatory potential. Endotoxin is known to be a contaminant of particle preparations and also stimulates the release of cytokines. It is usual to use a proprietary endotoxin test to avoid erroneous results. Four different formulations of cement were found to be free from endotoxin using standard, gelclot tests but stimulated different levels of release of cytokines from
The effect of conditioned media from implant revision membranes on tartrate resistant acid phosphatase (TRAP) secretion following PE exposure was investigated. Human Monocytes were cultured on PE/collagen coverslips, and 50 uls of culture media, conditioned media from implant revision membranes, or conditioned media from synovium was added. Cultured media were collected, and analyzed for TRAP activity. Statistical analysis showed significantly greater release of TRAP in the media with the supplement of the conditioned media from implant revision membranes, indicating that the unknown factors in the conditioned media could accelerate monocyte-macrophage TRAP secretion. Identifying and blocking of the factors would be beneficial for long-term implant performance. The purpose of this study was to investigate the effect of conditioned media from implant revision membranes on monocyte-macrophage tartrate resistant acid phosphatase (TRAP) secretion. Conditioned media from implant revision membranes significantly enhanced monocyte-macrophage TRAP secretion following PE exposure in vitro. Since TRAP has been related to bone resorption, identifying and blocking factors stimulating monocyte-macrophage TRAP section would be beneficial for preventing peri-implant bone resorption. Monocytes isolated from human blood were cultured on PE/collagen coverslips, and 50 uls of fresh culture media, conditioned media from implant revision membrane, or conditioned media from synovium was added at time zero, day two and four. Cultured media were collected at day two, four and six, and analyzed for TRAP activity. As previously reported the conditioned media from the revision membranes contained TRAP activity greater than synovial membranes. Therefore the accumulative TRAP activity after culturing
Inflammation has been associated with immunological dysfunctions and chronic inflammatory diseases but is important for normal repair processes like bone healing. Macrophages (mØ) are important for bone growth, maintenance, and regeneration. MØ are distinct from other bone cells and play an important role in the inflammatory stage of bone healing. Previous data has shown that ablation of mØs during the inflammatory stage can severely impair bone healing and exacerbate bone loss in osteoporotic models. However, little research has focused on characterizing the mØ subtypes found during the inflammatory stage. We hypothesized that different mØ subtypes are activated during inflammation and release factors to regulate bone repair. Therefore, bone marrow was collected from mice femurs at days 0, 1, 2, 4, and 7 after fracture and mØ were isolated using established methods. MØ subtypes were identified using anti-F4/80, anti-CD80, and anti-CD86 antibodies via flow cytometry and cytokine expression was quantified using Luminex. When compared to unfractured controls, a 40–50% increase in MHC class II+/CD80+ double positive mØs and MHC class II+/CD86+ double positive mØs were found on day 2 post-fracture, which remained elevated through day 4 or 7, respectively. No differences were found in mØ populations between femurs in naïve (unfractured) mice. mØs of the fractured limbs expressed higher levels of cytokines overtime. Our results suggest that different subtypes of mØs are present during the inflammatory stage and may support diverse functions such as effertocytosis, chemotaxis, and tissue anabolism or catabolism, which provides insight into their contribution in normal or uncontrolled inflammatory related processes and conditions.
Aims. Exosomes (exo) are involved in the progression of osteoarthritis (OA). This study aimed to investigate the function of dysfunctional chondrocyte-derived exo (DC-exo) on OA in rats and rat
In relation to regenerative therapies in osteoarthritis and cartilage repair, mesenchymal stromal cells (MSCs) have immunomodulatory functions and influence
Abstract. Objectives. In relation to regenerative therapies in osteoarthritis and cartilage repair, mesenchymal stromal cells (MSCs) have immunomodulatory functions and influence
Recent researches indicate that both M1 and M2
Aim. In the current study we aim to characterize the use of cationic host defense peptides (HDPs) as alternative antibacterial agents to include into novel antibacterial coatings for orthopedic implants. Staphyloccous aureus represent one the most challenging cause of infections to treat by traditional antibacterial therapies. Thanks to their lack of microbial resistance described so far, HDPs represent an attractive therapeutic alternative to antibiotics. Furthermore, HDPs have been showed to control infections via a dual function: direct antimicrobial activity and regulation of immune response. However, HDPs functions characterization and comparison is controversial, as changing test conditions or cell type used might yield different effects from the same peptide. Therefore, before moving towards the development of HDP-based coatings, we need to characterize and compare the immunomodulatory and antibacterial functions under the same conditions in vitro of 3 well-known cathelicidins: human LL-37, chicken CATH-2, and bovine-derived IDR-1018. Method. S. aureus, strain SH1000, was incubated with different concentrations of each HDP and bacterial growth was monitored overnight. Primary human monocytes were isolated from buffy coats using Ficoll-Paque density and CD14 microbeads, and differentiated for 7 days to
Mesenchymal stem cells (MSC) have potent immunomodulatory and regenerative effects via soluble factors. One approach to improve stem cell-based therapies is encapsulation of MSC in hydrogels based on natural proteins such as collagen and fibrin, which play critical roles in bone healing. In this work, we comparatively studied the influence of collagen and fibrin hydrogels of varying stiffness on the paracrine interactions established by MSC with
Tissue repair is believed to rely on tissue-resident progenitor cell populations proliferating, migrating, and undergoing differentiation at the site of injury. During these processes, the crosstalk between mesenchymal stromal/stem cells (MSCs) and
Tendinopathy is the most frequent musculoskeletal disease that requires medical attention. Mechanical overload has been considered as a key driver of its pathology. However, the underline mechanism on how overload induces tendinopathy and inflammation is unclear. Extracellular mitochondria (EM) are newly identified as cell-to-cell communicators. The aim of this study is to elucidate the role of mitochondria in overload-induced inflammation. We performed three-dimensional uniaxial stretching to mouse tendon organoid in bioreactors. Cyclic strain of uniaxial loadings included underload, normal load, and overload, according to previous work. We then harvested microvesicles including EM, from the bioreactor by differential centrifugation and evaluated their characteristics by flow cytometry and super-resolution confocal microscopy. Raw 264.7 mouse
Aim. Staphylococcus aureus (SA) can cause various infections and is associated with high morbidity and mortality rates of up to 40%. Antibiotic treatment often fails to eradicate SA infections even if the causative strain has been tested susceptible in vitro. The mechanisms leading to this persistence is still largely unknown. In our work, we to reveal SA interactions with host cells that allow SA to persist at the site of infection. Method. We established a sampling workflow to receive tissue samples from patients requiring surgical debridement due to SA bone-and joint or soft-tissue infections. We developed a multiplex immunofluorescent staining protocol which allowed us to stain for SA, leukocytes, neutrophils,
Abstract. Objectives. Tissue repair is believed to rely on tissue-resident progenitor cell populations proliferating, migrating, and undergoing differentiation at the site of injury. During these processes, the crosstalk between mesenchymal stromal/stem cells (MSCs) and
Macrophages play a critical role in innate immunity by promoting or inhibiting tissue inflammation and repair. Classically,
Macrophages (Mφ) are immune cells that play a crucial role in both innate and adaptive immunity as they are involved in a wide range of physiological and pathological processes. Depending on the microenvironment and signals present, Mφ can polarize into either M1 or M2 phenotypes, with M1