Bone Erosion Research Articles

Synovial microenvironment-influenced mast cells promote the progression of rheumatoid arthritis

Mast cells are phenotypically and functionally heterogeneous, and their state is possibly controlled by local microenvironment. Therefore, specific analyses are needed to understand whether mast cells function as powerful participants or dispensable bystanders in specific diseases. Here, we show that degranulation of mast cells in inflammatory synovial tissues of patients with rheumatoid arthritis (RA) is induced via MAS-related G protein-coupled receptor X2 (MRGPRX2), and the expression of MHC class II and costimulatory molecules on mast cells are upregulated. Collagen-induced arthritis mice treated with a combination of anti-IL-17A and cromolyn sodium, a mast cell membrane stabilizer, show significantly reduced clinical severity and decreased bone erosion. The findings of the present study suggest that synovial microenvironment-influenced mast cells contribute to disease progression and may provide a further mast cell-targeting therapy for RA.

On-demand release of a selective MMP-13 blocker from an enzyme-responsive injectable hydrogel protects cartilage from degenerative progression in osteoarthritis.

In osteoarthritis (OA), the degradation of cartilage is primarily driven by matrix metalloprotease-13 (MMP-13). Hence, the inhibition of MMP-13 has emerged as an attractive target for OA treatment. Among the various approaches that are being explored for MMP-13 regulation, blocking of the enzyme with specific binding molecules appears to be a more promising strategy for preventing cartilage degeneration. To enhance effectiveness and ensure patient compliance, it is preferable for the binding molecule to exhibit sustained activity when administered directly into the joint. Herein, we present an enzyme-responsive hydrogel that was designed to exhibit on-demand, the sustained release of BI-4394, a potent and highly selective MMP-13 blocker. The stable and compatible hydrogel was prepared using triglycerol monostearate. The efficacy of the hydrogel to prevent cartilage damage was assessed in a rat model of OA induced by anterior cruciate ligament transection (ACLT). The results revealed that in comparison to the rats administrated weekly with intra-articular BI-4394, the hydrogel implanted rats had reduced levels of inflammation and bone erosion. In comparison to untreated control, the cartilage in animals administered with BI-4394/hydrogel exhibited significant levels of collagen-2 and aggrecan along with reduced MMP-13. Overall, this study confirmed the potential of BI-4394 delivery using an enzyme-responsive hydrogel as a promising treatment option to treat the early stages of OA by preventing further cartilage degradation.

High-throughput micro-CT analysis identifies sex-dependent biomarkers of erosive arthritis in TNF-Tg mice and differential response to anti-TNF therapy.

Development of reliable disease activity biomarkers is critical for diagnostics, prognostics, and novel drug development. Although computed tomography (CT) is the gold-standard for quantification of bone erosions, there are no consensus approaches or rationales for utilization of specific outcome measures of erosive arthritis in complex joints. In the case of preclinical models, such as sexually dimorphic tumor necrosis factor transgenic (TNF-Tg) mice, disease severity is routinely quantified in the ankle through manual segmentation of the talus or small regions of adjacent bones primarily due to the ease in measurement. Herein, we sought to determine the particular hindpaw bones that represent reliable biomarkers of sex-dependent disease progression to guide future investigation and analysis. Hindpaw micro-CT was performed on wild-type (n = 4 male, n = 4 female) and TNF-Tg (n = 4 male, n = 7 female) mice at monthly intervals from 2-5 (females) and 2-8-months (males) of age, since female TNF-Tg mice exhibit early mortality from cardiopulmonary disease at approximately 5-6-months. Further, 8-month-old WT (n = 4) and TNF-Tg males treated with anti-TNF monoclonal antibodies (n = 5) or IgG placebo isotype controls (n = 6) for 6-weeks were imaged with micro-CT every 3-weeks. For image analysis, we utilized our recently developed high-throughput and semi-automated segmentation strategy in Amira software. Synovial and osteoclast histology of ankle joints was quantified using Visiopharm. First, we demonstrated that the accuracy of automated segmentation, determined through analysis of ~9000 individual bones by a single user, was comparable in wild-type and TNF-Tg hindpaws before correction (79.2±8.9% vs 80.1±5.1%, p = 0.52). Compared to other bone compartments, the tarsal region demonstrated a sudden, specific, and significant bone volume reduction in female TNF-Tg mice, but not in males, by 5-months (4-months 4.3± 0.22 vs 5-months 3.4± 0.62 mm3, p<0.05). Specifically, the cuboid showed significantly reduced bone volumes at early timepoints compared to other tarsals (i.e., 4-months: Cuboid -24.1±7.2% vs Talus -9.0±5.9% of 2-month baseline). Additional bones localized to the anterolateral region of the ankle also exhibited dramatic erosions in the tarsal region of females, coinciding with increased synovitis and osteoclasts. In TNF-Tg male mice with severe arthritis, the talus and calcaneus exhibited the most sensitive response to anti-TNF therapy measured by effect size of bone volume change over treatment period. We demonstrated that sexually dimorphic changes in arthritic hindpaws of TNF-Tg mice are bone-specific, where the cuboid serves as a reliable early biomarker of erosive arthritis in female mice. Adoption of automated segmentation approaches in pre-clinical or clinical models has potential to translate quantitative biomarkers to monitor bone erosions in disease and evaluate therapeutic efficacy.

A bioactive and biodegradable vitamin C stearate-based injectable hydrogel alleviates experimental inflammatory arthritis.

Rheumatoid arthritis (RA) is a chronic autoimmune inflammatory joint disorder affecting nearly 1% of the global population. In RA, synovial joints are infiltrated by inflammatory mediators and enzymes, leading to articular cartilage deterioration, joint damage, and bone erosion. Herein, the 9-aminoacridine-6-O-stearoyl-L-ascorbic acid hydrogel (9AA-SAA hydrogel) was formulated by the heat-cool method and further characterized for surface charge, surface morphology, rheology, and cytocompatibility. Furthermore, we evaluated the therapeutic efficacy of the 9AA-SAA hydrogel, an enzyme-responsive drug delivery system with on-and-off switching capabilities based on disease severity against collagen-induced experimental arthritis in Wistar rats. The anti-inflammatory action of the US FDA-approved drug 9-aminoacridine (9AA) was revealed which acted through nuclear receptor subfamily 4 group A member 1 (NR4A1), an anti-inflammatory orphan nuclear receptor that inhibits nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kB). Furthermore, we have explored the role of ascorbic acid, an active moiety of 6-O-stearoyl-L-ascorbic acid (SAA), in promoting the production of collagen production through ten-eleven translocation-2 (TET2) upregulation. Targeting through NR4A1 and TET2 could be the probable mechanism for the treatment of experimental arthritis. The combination of 9AA and ascorbic acid demonstrated enhanced therapeutic efficacy in the 9AA-SAA hydrogel, significantly reducing the severity of experimental arthritis. This approach, in contrast to existing treatments with limited effectiveness, presents a promising and more effective strategy for RA treatment by mitigating inflammation in experimental arthritis.

Clinical and imaging findings in enteropathic spondyloarthritis with special emphasize in diagnostic delay: a cross-sectional study.

Enteropathic spondyloarthritides (eSpAs) are chronic inflammatory joint diseases associated with inflammatory bowel disease (IBD). Limited data are available on the prevalence since arthritis in IBD patients may be underestimated because medications may hide disease activity with a possible diagnostic delay. We aimed to evaluate diagnostic delay in eSpA and explore associated demographic, clinical, and radiographic characteristics. Single-centre cross-sectional study conducted on consecutive out-patients referred to the combined Gi-Rhe clinic (November 2018-October 2019). We analysed eSpA patients for diagnostic delay, disease activity, inflammatory markers, conventional radiography (CR) and magnetic resonance images (MRI) of sacroiliac joints/spine. A total of 190 eSpA patients [118 peripheral SpA, 72 axial (Ax) SpA including 44 non-radiographic (nr)-axSpA] were enrolled. axSpA patients had a higher prevalence of men sex, HLA-B27 positivity, uveitis and pancolitis compared with peripheral eSpA. Median diagnostic delay in eSpA was 48 months (IQR 6-77) with no difference between axial and peripheral patients. Radiographic-axial SpA (r-axSpA) patients displayed a higher diagnostic delay compared with nr-axSpA (median/IQR 36/17-129 versus 31/10-57 months, p = 0.03) and were older, with longer disease duration, low education status and high rate of employment than patients with nr-axSpA. r-axSpA patients with sclerosis, syndesmophytes and bridge at CR had higher diagnostic delay than those without lesions. Men showed higher prevalence of spine damage lesions than women as sclerosis, squaring, syndesmophytes and bridges. Longer disease duration was detected in patients with radiographic damage as bridge and sacroiliitis grade 3. On MRI, sacroiliac bone oedema was associated with reduced diagnostic delay, whereas bone erosions were associated with higher diagnostic delay compared with that in patients without these lesions. Patients with psoriasis displayed a higher diagnostic delay compared to those without skin involvement. Diagnostic delay was higher in r-axSpA compared with nr-axSpA despite the same treatment. Demographic, clinical features and radiological lesions were associated with diagnostic delay.

Clinical Implications of Catabolic and Anabolic Bone Changes in Psoriatic Arthritis

Psoriatic arthritis (PsA) is a complex inflammatory condition characterized by both catabolic and anabolic changes that significantly impact patient outcomes. Catabolic processes in PsA primarily manifest as bone erosions and joint destruction. These changes result from the inflammation triggered by cytokines, which promotes osteoclast activation and increased bone resorption. On the other hand, anabolic changes are observed through the formation of enthesiophytes, bony projections that develop at the sites where tendons and ligaments attach to bone. This process is often seen as compensatory response to chronic inflammation and mechanical stress. Clinicians should adopt a holistic approach that not only focuses on alleviating symptoms but also considers the long-term implications of these bone changes. Understanding the dynamics of catabolic and anabolic changes in PsA is essential for developing effective treatment strategies and improving patient outcomes. By recognizing the significance of both bone erosions and enthesiophyte formation, healthcare providers can better tailor their interventions, ensuring a comprehensive management plan that addresses both inflammation and structural integrity.

Erosion Regression in Patients with RA After Upadacitinib-A Pilot Study Using High Resolution Peripheral Quantitative Computed Tomography

Background: Janus kinases inhibitor (JAKi) is a potent drug in treating patients with rheumatoid arthritis (RA). However, the effect of JAKi on finite structural changes remained uncertain. This study aims to investigate the effect of JAKi on erosion repair evaluated by high-resolution peripheral quantitative computer tomography (HR-pQCT) in patients with active RA. Methods: This was a prospective, non-randomized pilot study. We enrolled 20 adult patients with active RA with [Formula: see text]1 bone erosion on HR-pQCT. They were given upadacitinib 15mg once daily for 24 weeks. HR-pQCT of the metacarpophalangeal joint was performed at baseline and 24-week. The serum bone biomarkers level was evaluated before and after treatment. Twenty age-and-sex matched RA patients from another study treated with conventional synthetic disease modifying anti-rheumatic drugs (csDMARDs) were included as active controls. Results: Nineteen patients in the upadacitinib group completed the study procedures. After 24 weeks, despite similar improvement in disease activity, a reversed trend in the mean erosion volume change on HR-pQCT was observed comparing the upadacitinib and active control group (upadacitinib group: -0.23± 3.26mm3vs control group: 1.32± 6.05mm3, p=0.131). A greater proportion of erosions in the upadacitinib group demonstrated regression (27% vs 12%, p=0.085). Using general estimating equation (GEE), the use of upadacitinib was significantly associated with erosion regression (OR: 3.61, 95% CI: 1.00-13.00, p=0.049) after adjusting for the difference in disease duration. The serum levels of bone resorption markers reduced after upadacitinib treatment. No new safety signal was noted. Conclusion: Despite a similar improvement in RA disease activity after upadacitinib compared to csDMARDs, a differential regression of erosion on HR-pQCT was observed in patients received upadacitinib. The potential role of JAK1 inhibition in erosion repair should be investigated.

Imaging in psoriatic arthritis: established methods and emerging techniques.

Psoriatic arthritis (PsA) is a heterogeneous, chronic, inflammatory musculoskeletal disease that can lead to peripheral and axial damage and loss of function. A clear difference between PsA and other forms of inflammatory arthritis is the different forms of bone remodeling seen in PSA which incorporates not only increased bone resorption with bone erosions, osteolysis, and loss of bone mineral density but also increased bone formation with periostitis, syndesmophytes, enthesiophytes, and ankylosis. PsA, if diagnosed late, will lead to significant structural damage, the most severe form of which is known as arthritis mutilans, and loss of physical function. Imaging plays a crucial role in diagnosing and monitoring both peripheral and axial conditions associated with PsA. Radiography is currently the main modality used to monitor structural damage in PsA though commonly used scoring systems do not include bony proliferation as a criterion. Besides, radiography is limited in determining the presence and cause of periarticular soft tissue thickening, which may arise from tendinosis, tenosynovitis, synovial proliferation, bursitis, or enthesitis. Recently, much more attention has been paid to determining the imaging characteristics of PsA, which enables more precise identification of disease and severity assessment. Newer imaging technologies also enable variations in normal bone microstructure to be distinguished from disease-related abnormality. This review discusses the current state of innovative imaging modalities in PsA, specifically concentrating on their roles in PsA diagnosis and treatment, improving the early detection of PsA, and identifying patients with skin psoriasis at risk of developing psoriatic arthritis.

Rare Indication of Atlantoaxial Fusion-failed Conservative Management of Primary Atlantoaxial Osteoarthritis

Introduction: Osteoarthritis of the atlantoaxial joint is a significant cause of occipitocervical pain, which is often missed and has an increasing prevalence with age. The patients typically present with occipitocervical pain and restricted and painful neck rotations. Despite the primary reliance on conservative management for this pathology, surgical intervention becomes crucial for those not responding to standard conservative treatment. The presented case series highlights the rarity of the requirement of surgical intervention in the management of Atlantoaxial osteoarthritis (AAOA) and the clinical outcomes of surgical management in AAOA. Case Report: This paper presents a case series of four patients who were managed surgically with atlantoaxial fusion, from a database of 108 patients with AAOA. The case series includes three males and one female with a mean age of presentation being 67.5 years. All four patients presented with occipitocervical pain, and painful neck movements and were diagnosed with AAOA on the anteroposterior open mouth view radiographs showing changes of osteoarthritis such as bone erosions, sclerosis, osteophytes. The patients were managed conservatively with non-steroidal anti-inflammatory drugs, intra-articular steroid injections, and cervical collar immobilization. Those not responding to conservative management and with incapacitating pain were managed surgically with atlantoaxial fusion procedures. Conclusion: In a group of patients with a painful and debilitating degenerative AAOA only a small proportion of cases require surgical intervention. In this cohort, only 3.70 % of patients required surgery, highlighting the rarity of surgical intervention required in the management of AAOA. Nevertheless, when conducted, atlantoaxial fusion has proved to be efficacious with a low rate of serious complications and the patient self-rated outcome in terms of post-operative visual analog scale score and neck disability index scores indicating a high degree of satisfaction with the procedures. Keywords: Atlantoaxial, osteoarthritis, fusion, transarticular screws.

Bitongqing Attenuates CIA Rats by Suppressing Macrophage Pyroptosis and Modulating the NLRP3/Caspase-1/GSDMD Pathway.

Rheumatoid arthritis (RA) is an autoimmune disease characterized by synovitis and inflammatory cell infiltration. The traditional Chinese medicine prescription, Bitongqing (BTQ) exhibited significant efficacy in the clinical treatment of RA. However, the potential therapeutic mechanisms of BTQ in treating RA have not been fully investigated. This study aims to elucidate the effect of BTQ on collagen-induced arthritis (CIA) rat macrophage pyroptosis, providing a theoretical basis for treating RA. This research employed liquid chromatography-mass spectrometry (LC-MS) to identify the primary components of BTQ. The therapeutic effects of BTQ were evaluated in a rat model of CIA. In vivo experiments were conducted using pathohistological staining, immunofluorescence, micro-CT, and Western blotting. Next, Mouse leukemia cells of monocyte macrophage cells (RAW264.7) were induced to undergo pyroptosis using lipopolysaccharide (LPS) and adenosine triphosphate (ATP), and the impact of BTQ on RAW264.7 macrophages was assessed through cell viability, immunofluorescence analysis, lactate dehydrogenase (LDH) secretion measurement, and Western blotting. BTQ had a therapeutic effect on CIA rats, which was mainly manifested as a reduction in joint inflammation, foot swelling, bone erosion, and amelioration of pathological changes in these rats. Further studies revealed that BTQ inhibited the levels of cytokine production interleukin-18 (IL-18) and interleukin-1β (IL-1β), and likewise, it inhibited the expression of key proteins in the NOD-like receptor thermal protein domain associated protein 3 (NLRP3) mediated pyroptosis in the synovial tissues of CIA rats. The results of in vitro experiments demonstrated that BTQ attenuated LDH secretion, decreased IL-18 and IL-1β cytokine production, and downregulated expression of key proteins involved in the NLRP3-mediated pyroptosis on RAW264.7 macrophages. The therapeutic potential of BTQ in CIA lies in its ability to inhibit NLRP3-mediated macrophage pyroptosis, thereby suggesting a promising strategy for the treatment of RA.

Interleukin 6 and Bone Erosions in Rheumatoid Arthritis in an African Hospital

Interleukin 6 and Bone Erosions in Rheumatoid Arthritis in an African Hospital

AdipoR1 promotes pathogenic Th17 differentiation by regulating mitochondrial function through FUNDC1.

Adiponectin receptor 1 ( Adipor1) deficiency has been shown to inhibit Th17 cell differentiation and reduce joint inflammation and bone erosion in antigen-induced arthritis (AIA) mice. Additional emerging evidence indicates that Th17 cells may differentiate into pathogenic (pTh17) and non-pathogenic (npTh17) cells, with the pTh17 cells playing a crucial role in numerous autoimmune and inflammatory conditions. In the current study, we found that Adipor1 deficiency inhibited pTh17 differentiation in vitro and that the deletion of Adipor1 in pTh17 cells reduced the mitochondrial function. RNA-sequencing (RNA-seq) demonstrated a significant increase in the expression levels of Fundc1, a gene related to mitochondrial function, in Adipor1-deficient CD4 + T cells. Interference with the Fundc1 expression in Adipor1-deficient CD4 + T cells partially mitigated the effect of Adipor1 deficiency on mitochondrial function and pTh17 differentiation. In conclusion, the current study demonstrated a novel role of AdipoR1 in regulating mitochondrial function via FUNDC1 to promote pTh17 cell differentiation, providing some insights into potential therapeutic targets for autoimmune and inflammatory diseases.

Assessment of Musculoskeletal Ultrasound of Rheumatoid Arthritis.

Musculoskeletal ultrasound (MSUS) is a valuable tool that is used in outpatient clinics or at the bedside to assess multiple joint sites, including small joints. It provides detailed images of structures commonly observed in rheumatoid arthritis (RA), such as synovitis, tenosynovitis, bone erosions, cartilage damage, and synovial fluid accumulation. MSUS is frequently used in the management of RA and provides more objective information for an early diagnosis and disease activity assessment through imaging findings.

Administration of Liposomal-Based Pde3b Gene Therapy Protects Mice Against Collagen-Induced Rheumatoid Arthritis via Modulating Macrophage Polarization.

Rheumatoid arthritis (RA) is a chronic and systemic autoimmune disease characterized by synovial inflammation and joint destruction. Despite progress in RA therapy, it remains difficult to achieve long-term remission in RA patients. Phosphodiesterase 3B (Pde3b) is a member of the phosphohydrolyase family that are involved in many signal transduction pathways. However, its role in RA is yet to be fully addressed. Studies were conducted in arthritic DBA/1 mice, a suitable mouse strain for collagen-induced rheumatoid arthritis (CIA), to dissect the role of Pde3b in RA pathogenesis. Next, RNAi-based therapy with Pde3b siRNA-loaded liposomes was assessed in a CIA model. To study the mechanism involved, we investigated the effect of Pde3b knockdown on macrophage polarization and related signaling pathway. We demonstrated that mice with CIA exhibited upregulated Pde3b expression in macrophages. Notably, intravenous administration of liposomes loaded with Pde3b siRNA promoted the macrophage anti-inflammatory program and alleviated CIA in mice, as indicated by the reduced inflammatory response, synoviocyte infiltration, and bone and cartilage erosion. Mechanistic study revealed that depletion of Pde3b increased cAMP levels, by which it enhanced PKA-CREB-C/EBPβ pathway to transcribe the expression of anti-inflammatory program-related genes. Our results support that Pde3b is involved in the pathogenesis of RA, and Pde3b siRNA-loaded liposomes might serve as a promising therapeutic approach against RA.

Expressão de TLR-2, FOXP3 e COX-2 na membrana sinovial de cães com artrite induzida pela leishmaniose canina

ABSTRACT: Canine leishmaniasis (CanL) is a multifaceted disease triggered by the protozoan Leishmania infantum, characterized by diverse clinical presentations, including osteoarticular complications. Immune-mediated joint diseases invariably initiate at the synovial membrane, implicating its pivotal role in arthritis pathogenesis. This study aimed to investigate the influence of natural L. infantum infection on synovial fluid characteristics and the expression of immune markers, including TLR-2, FOXP3, and COX-2, in the synovial membrane. Twenty naturally infected dogs (NID) with L. infantum were sourced from the Zoonosis Surveillance Unit (ZSU). Clinical-orthopedic assessments were conducted, encompassing lameness, joint edema, crepitus, patellar luxation, and the drawer test. Synovial fluid (SF) parameters, including volume, appearance, viscosity, total nucleated cell count (TNC), neutrophil count, and total protein (TP) content, were determined. After anesthesia and euthanasia, synovial membrane specimens were obtained. SF protein concentrations categorized dogs into three groups: GI (2 to 2.5g/dL), GII (2.5 to 6.0g/dL), and GIII (&gt;6g/dL). Inflammatory infiltrates and synovial membrane changes were assessed, and immunohistochemistry evaluated TLR-2, FOXP3, and COX-2 marker expressions. Clinical evaluations revealed various osteoarticular abnormalities in NID dogs, including lameness (55%), joint edema (25%), crepitus (30%), patellar luxation (20%), and positive drawer test (25%). Post mortem examinations revealed bilateral subchondral bone, meniscus, and trochlea erosion in 30% of cases. Amastigotes of L. infantum were identified extracellularly and within macrophages (60%). An inflammatory infiltrate was predominant in 70% of dogs, with varying intensity among the groups. Mononuclear cells, chiefly macrophages and lymphocytes, and neutrophils comprised the infiltrate. TLR-2 and COX-2 expression levels were elevated in GIII compared to GII and GI. Conversely, FOXP3 showed moderate expression in GI and minimal expression in GII and GIII. This study underscores the contributory role of L. infantum infection in the development of joint lesions in CanL. Additionally, alterations in the expression of immune markers TLR2, FOXP3, and COX2 within the synovial membrane imply the perpetuation and exacerbation of the inflammatory processes, shedding light on the intricate pathogenesis of CanL-induced arthritis.

Effect of Achieving Sustained SDAI Remission on Erosion Healing in Early Rheumatoid Arthritis - A One-year Prospective HR-pQCT Study

Background Rheumatoid arthritis (RA) is a chronic inflammatory disease with progressive joint destruction. High-resolution peripheral quantitative CT (HR-pQCT) is a novel technique for detailed bone microstructure analysis allowing volumetric assessment of bone erosions. While most patients demonstrating little baseline joint damage on radiography in the early stage of RA, whether achieving simple disease activity index (SDAI) remission can lead to better structural outcome is to be confirmed. Methods Patients with ERA were recruited and treated to the target of simple disease activity index (SDAI) remission using a standardized algorithm. One hundred patients who received the one-year tight-control treatment were grouped by achieving SDAI sustained LDA [SDAI [Formula: see text] at 6, 9 and 12 months (sLDA group) or not (non-sLDA group). HR-pQCT of the second to fourth metacarpophalangeal joints were performed at baseline, month 6 and one-year. Erosion volume and marginal bone mineral density (BMD) were measured. On an individual patient basis, erosion progression was defined as at least one erosion showing (1) an increase in erosion volume exceeding the smallest detectable change [SDC] (0.08 mm 3) AND (2) a decrease in marginal BMD exceeding SDC (7.8 mmHA/cm 3). Erosion healing was defined as at least one erosion showing (1) a reduction in erosion volume greater than SDC AND an increase in BMD exceeding SDC OR complete disappearance of the lesion AND (2) the absence of any erosion progression. Results Fourteen patients (12.8%) achieved sustained SDAI remission from 6-12 months (SDI group). After 12 months, a significant reduction in erosion volume and marginal osteosclerosis was observed in both groups. The SDI group showed a lower incidence of erosion progression (increase in volume [Formula: see text]0.08mm 3 and decrease in marginal osteosclerosis [Formula: see text]7.8mg HA/cm 3 : 0% vs 16%, p=0.135) and exhibited a higher rate of erosion healing (56% vs 29%, p=0.083) compared with the non-SDI group. In the GEE model, patients in the SDI group showed a higher likelihood of erosion healing (OR: 2.976, 95% CI: 1.0 - 8.9, p=0.050). The changes in erosion depth and width were similar between two groups. Conclusion Achieving sustained SDAI remission could improve erosion healing and limit erosion progression in patients with ERA.

Artemisinic acid attenuates osteoclast formation and titanium particle-induced osteolysis via inhibition of RANKL-induced ROS accumulation and MAPK and NF-κB signaling pathways.

Periprosthetic osteolysis (PPO) is the most common cause of joint arthroplasty failure. Its progression involves both biological and mechanical factors. Osteoclastogenesis induced by wear from debris-cell interactions, ultimately leading to excessive bone erosion, is considered the primary cause of PPO; therefore, targeting osteoclasts is a promising treatment approach. Currently available drugs have various side effects and limitations. Artemisinic acid (ArA) is a sesquiterpene isolated from the traditional herb Artemisia annua L. that has various pharmacological effects, such as antimalarial, anti-inflammatory, and antioxidant activities. Therefore, this study was aimed at investigating the effect of ArA on osteoclast formation and bone resorption function in vitro, as well as wear particle-induced osteolysis in vivo, and to explore its molecular mechanism of action. Here, we report that ArA inhibits RANKL-stimulated osteoclast formation and function. Mechanistically, ArA suppresses intracellular reactive oxygen species levels by activating the antioxidant response via nuclear factor erythroid-2-related factor 2 (Nrf2) pathway upregulation. It also inhibits the mitogen-activated kinases (MAPK) and nuclear factor-κB (NF-κB) pathways, as well as the transcription and expression of NFATc1 and c-Fos. In vivo experiments demonstrated that ArA reduces osteoclast formation and alleviates titanium particle-induced calvarial osteolysis. Collectively, our study highlights that ArA, with its osteoprotective and antioxidant effects, is a promising therapeutic agent for preventing and treating PPO and other osteoclast-mediated osteolytic diseases.

Scanning Electron Microscopic Analysis of the Bone-Resorption Activity in Mature Osteoclasts.

Bone homeostasis depends on the balance between bone deposition and bone resorption, which are mediated by the activity of osteoblasts and osteoclasts, respectively. Blocking osteoclast activity can be a therapeutic strategy in rheumatoid arthritis (RA) to reduce subsequent bone erosion. Therefore, investigating the activity of osteoclasts is essential for understanding the pathology of RA. Bone-resorption pits, which are caused by activated osteoclasts, are significantly increased in RA. Scanning electron microscopic analysis of bone-resorption pits is an effective method for understanding the pathology of RA. This chapter describes the method for observing the surface microstructure of pit formation on bone slices.

Yishen Tongbi decoction attenuates inflammation and bone destruction in rheumatoid arthritis by regulating JAK/STAT3/SOCS3 pathway.

Yishen-Tongbi Decoction (YSTB), a traditional Chinese prescription, has been used to improve syndromes of rheumatoid arthritis (RA) for many years. Previous research has shown that YSTB has anti-inflammatory and analgesic properties. However, the underlying molecular mechanism of the anti-RA effects of YSTB remains unclear. The purpose of this research was to investigate how YSTB affected mice with collagen-induced arthritis (CIA) and RAW264.7 cells induced with lipopolysaccharide (LPS). The findings show that YSTB could significantly improve the clinical arthritic symptoms of CIA mice (mitigate paw swelling, arthritis score, thymus and spleen indices, augment body weight), downregulated expression of pro-inflammatory cytokines like tumor necrosis factor-alpha (TNF-α), interleukin-1β (IL-1β), IL-6 and IL-17, while upregulated the level of anti-inflammatory like IL-10 and transforming growth factor-β (TGF-β). Meanwhile, YSTB inhibits bone erosion and reduces inflammatory cell infiltration, synovial proliferation, and joint destruction in CIA mice. In addition, we found that YSTB was able to suppress the LPS-induced inflammation of RAW264.7 cells, which was ascribed to the suppression of nitric oxide (NO) production and reactive oxygen species formation (ROS). YSTB also inhibited the production of inducible nitric oxide synthase and reduced the releases of pro-inflammatory cytokines TNF-α, IL-1β, and IL-6 in LPS-induced RAW264.7 cells. Furthermore, the phosphorylation expression of JAK2, JAK3, STAT3, p38, ERK and p65 protein could be suppressed by YSTB, while the expression of SOCS3 could be activated. Taken together, YSTB possesses anti-inflammatory and prevention bone destruction effects in RA disease by regulating the JAK/STAT3/SOCS3 signaling pathway.

Gubi Zhitong formula alleviates osteoarthritis in vitro and in vivo via regulating BNIP3L-mediated mitophagy

BackgroundOsteoarthritis (OA) is characterized by degeneration of articular cartilage, leading to joint pain and dysfunction. Gubi Zhitong formula (GBZTF), a traditional Chinese medicine formula, has been used in the clinical treatment of OA for decades, demonstrating definite efficacy. However, its mechanism of action remains unclear, hindering its further application. MethodsThe ingredients of GBZTF were analyzed and performed with liquid chromatography-mass spectrometry (LC-MS). 6 weeks old SD rats were underwent running exercise (25 m/min, 80 min, 0°) to construct OA model with cartilage wear and tear. It was estimated by Micro-CT, Gait Analysis, Histological Stain. RNA-seq technology was performed with OA Rats' cartilage, and primary chondrocytes induced by IL-1β (mimics OA chondrocytes) were utilized to evaluated and investigated the mechanism of how GBZTF protected OA cartilage from being damaged with some functional experiments. ResultsA total of 1006 compounds were identified under positive and negative ion modes by LC-MS. Then, we assessed the function of GBZTF through in vitro and vivo. It was found GBZTF could significantly up-regulate OA rats’ limb coordination and weight-bearing capacity, and reduce the surface and sub-chondral bone erosions of OA joints, and protect cartilage from being destroyed by inflammatory factors (iNOS, IL-6, IL-1β, TNF- α, MMP13, ADAMTS5), and promote OA chondrocytes proliferation and increase the S phage of cell cycle. In terms of mechanism, RNA-seq analysis of cartilage tissues revealed 1,778 and 3,824 differentially expressed genes (DEGs) in model vs control group and GBZTF vs model group, respectively. The mitophagy pathway was most significantly enriched in these DEGs. Further results of subunits of OA chondrocytes confirmed that GBZTF could alleviate OA-associated inflammation and cartilage damage through modulation BCL2 interacting protein 3-like (BNIP3L)-mediated mitophagy. ConclusionThe therapeutic effectiveness of GBZTF on OA were first time verified in vivo and vitro through functional experiments and RNA-seq, which provides convincing evidence to support the molecular mechanisms of GBZTF as a promising therapeutic decoction for OA.