Cytokine-mediated bone destruction in rheumatoid arthritis

The role of TNF-α in osteoporosis, bone repair and inflammatory bone diseases: A review

Tumour necrosis factor alpha (TNF-α) is a pleiotropic cytokine synthesised primarily by mononuclear cells; it has a potent pro-inflammatory effect, playing a crucial role in metabolic, immune, and inflammatory diseases. This cytokine has been studied in various biological systems. In bone tissue, TNF-α plays an integral role in skeletal disorders such as osteoporosis, fracture repair and rheumatoid arthritis through its involvement in regulating the balance between osteoblasts and osteoclasts, mediating inflammatory responses, promoting angiogenesis and exacerbating synovial proliferation. The biological effect TNF-α exerts in this context is determined by a combination of the signalling pathway it activates, the type of receptor it binds, and the concentration and duration of exposure. This review summarises the participation and pathophysiological role of TNF-α in osteoporosis, bone damage repair, chronic immunoinflammatory bone disease and spinal cord injury, and discusses its main mechanisms.

The Role of Mesenchymal Stromal Cells in the Treatment of Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a chronic inflammatory joint disease characterised by the formation of a hyperplastic pannus, as well as cartilage and bone damage. The pathogenesis of RA is complex and involves broad interactions between various cells present in the inflamed synovium, including fibroblast-like synoviocytes (FLSs), macrophages, and T cells, among others. Under inflammatory conditions, these cells are activated, further enhancing inflammatory responses and angiogenesis and promoting bone and cartilage degradation. Novel treatment methods for RA are greatly needed, and mesenchymal stromal cells (MSCs) have been suggested as a promising new regenerative and immunomodulatory treatment. In this paper, we present the interactions between MSCs and RA-FLSs, and macrophages and T cells, and summarise studies examining the use of MSCs in preclinical and clinical RA studies.

Correlation of serum matrix metalloproteinase 3 with osteoporosis in patients of postmenopausal rheumatoid arthritis

Osteoporosis (OP) is a common complication of postmenopausal women with rheumatoid arthritis (RA). Herein, the objective of our study was to explore the correlation between serum matrix metalloproteinase 3 (MMP3) and OP among postmenopausal women with RA to foster better diagnosis and treatment. A total of 208 elderly postmenopausal women with RA were included in this study, with 83 patients diagnosed with OP after RA diagnosis and 125 patients without OP. Serum MMP3 levels and bone mineral density (BMD) were measured and compared. The predictive value of serum MMP3 for OP in this population was also analyzed using receiver operating curve (ROC) analysis. Postmenopausal women with RA and OP diagnosis had markedly higher serum MMP3 levels, compared to those without OP. ROC analysis showed that serum MMP3 had predictive value for OP. Additionally, a negative correlation was observed between serum MMP3 levels and BMD. High serum MMP3 levels were also found to be associated with high abnormal bone metabolism. We found that serum MMP3 levels are strongly correlated with OP in postmenopausal women with RA and that elevated levels of serum MMP3 are linked to low BMD and high abnormal bone metabolism. Serum MMP3 may be a useful biomarker for predicting OP in this population, and could potentially aid in the development of targeted prevention and treatment strategies.

Relationship between the phase angle from bioelectrical impedance analysis and daily physical activity in patients with rheumatoid arthritis

OBJECTIVES

This study aimed to examine the relationship between daily physical activity and the phase angle (PhA) obtained by bioelectrical impedance analysis in rheumatoid arthritis (RA) patients.

METHODS

Data from a prospective cohort study of RA patients who were surveyed every year were analysed. The PhA was assessed by the bioelectrical impedance analysis method, and physical activity was assessed as the amount of time of exercise in metabolic equivalents (METs) per day using a triaxial accelerometer for 7 consecutive days. The association between physical activity and the PhA was evaluated using the isotemporal substitution model in multiple regression analysis.

RESULTS

Seventy-six RA patients were included in the analysis (81% female and age 66.2 ± 13.1 years). On cross-sectional analysis, the isotemporal substitution model in multiple regression analysis showed that the PhA was 0.05 points higher every 10 minutes when activities with intensity of 1 ≤ METs < 2 were replaced by activities with intensity of ≥3 METs (P = .01). Over 1 year, the rate of change in the PhA was 0.69% higher every 10 minutes when activities with intensity of 1 ≤ METs < 2 were replaced by activities with intensity of ≥3 METs (P = .037).

CONCLUSION

The PhA in RA patients may be related to physical activity level.

Recent advances of NFATc1 in rheumatoid arthritis-related bone destruction: mechanisms and potential therapeutic targets

Rheumatoid arthritis (RA) is a chronic autoimmune inflammatory disease characterized by inflammation of the synovial tissue and joint bone destruction, often leading to significant disability. The main pathological manifestation of joint deformity in RA patients is bone destruction, which occurs due to the differentiation and proliferation of osteoclasts. The transcription factor nuclear factor-activated T cell 1 (NFATc1) plays a crucial role in this process. The regulation of NFATc1 in osteoclast differentiation is influenced by three main factors. Firstly, NFATc1 is activated through the upstream nuclear factor kappa-B ligand (RANKL)/RANK signaling pathway. Secondly, the Ca2+-related co-stimulatory signaling pathway amplifies NFATc1 activity. Finally, negative regulation of NFATc1 occurs through the action of cytokines such as B-cell Lymphoma 6 (Bcl-6), interferon regulatory factor 8 (IRF8), MAF basic leucine zipper transcription factor B (MafB), and LIM homeobox 2 (Lhx2). These three phases collectively govern NFATc1 transcription and subsequently affect the expression of downstream target genes including TRAF6 and NF-κB. Ultimately, this intricate regulatory network mediates osteoclast differentiation, fusion, and the degradation of both organic and inorganic components of the bone matrix. This review provides a comprehensive summary of recent advances in understanding the mechanism of NFATc1 in the context of RA-related bone destruction and discusses potential therapeutic agents that target NFATc1, with the aim of offering valuable insights for future research in the field of RA. To assess their potential as therapeutic agents for RA, we conducted a drug-like analysis of potential drugs with precise structures.

Transcriptomic characterization of classical monocytes highlights the involvement of immuno-inflammation in bone erosion in Rheumatoid Arthritis

Introduction

Evidence-based data suggest that under inflammatory conditions, classical monocytes are the main source of osteoclasts and might be involved in bone erosion pathophysiology. Here, we analyze the transcriptomic profile of classical monocytes in erosive and non-erosive rheumatoid arthritis patients in order to better understand their contribution to bone erosion.

Methods

Thirty-nine premenopausal RA patients were consecutively enrolled and divided into two groups based on the presence of bone erosions on hand joints. Classical monocytes were isolated from peripheral blood through negative selection, and RNA-seq was performed using a poly-A enrichment kit and Illumina® platform. Classical monocytes transcriptome from healthy age-matched women were also included to identify differentially expressed genes (DEGs). Therefore, gene sets analysis was performed to identify the enriched biological pathways.

Results

RNA-seq analysis resulted in the identification of 1,140 DEGs of which 89 were up-regulated and 1,051 down-regulated in RA patients with bone erosion compared to those without bone erosions. Among up-regulated genes, there was a highlighted expression of IL18RAP and KLF14 related to the production of pro-inflammatory cytokines, innate and adaptive immune response. Genes related to collagen metabolism (LARP6) and bone formation process (PAPPA) were down-regulated in RA patients with erosions. Enriched pathways in patients with erosions were associated with greater activation of immune activation, and inflammation. Interestingly, pathways associated with osteoblast differentiation and regulation of Wnt signaling were less activated in RA patients with erosions.

Conclusion

These findings suggest that alterations in expression of monocyte genes related to the inflammatory process and impairment of bone formation might have an important role in the pathophysiology of bone erosions in RA patients.

The Fidelity of Rheumatoid Arthritis Multivariate Diagnostic Biomarkers Using Discriminant Analysis and Binary Logistic Regression

Rheumatoid arthritis (RA) is an autoimmune inflammatory disease that causes multi-articular synovitis. The illness is characterized by worsening inflammatory synovitis, which causes joint swelling and pain. Synovitis erodes articular cartilage and marginal bone, resulting in joint deterioration. This bone injury is expected to be permanent. Cytokines play a prominent role in the etiology of RA and could be useful as early diagnostic biomarkers. This research was carried out at Riyadh's King Khalid University Hospital (KKUH). Patients were enrolled from the Rheumatology unit. Seventy-eight RA patients were recruited (67 (85.9%) females and 11 (14.1%) males). Patients were selected for participation by convenience sampling. Demographic data were collected, and disease activity measurements at 28 joints were recorded using the disease activity score (DAS-28). Age- and sex-matched controls from the general population were included in the study. A panel of 27 cytokines, chemokines, and growth factors was determined in patient and control sera. Binary logistic regression (BLR) and discriminant analysis (DA) were used to analyze the data. We show that multiple cytokine biomarker profiles successfully distinguished RA patients from healthy controls. IL-17, IL-4, and RANTES were among the most predictive variables and were the only biomarkers incorporated into both BLR and DA predictive models for pooled participants (men and women). In the women-only models, the significant cytokines incorporated in the model were IL-4, IL-17, MIP-1b, and RANTES for the BLR model and IL-4, IL-1Ra, GM-CSF, IL-17, and eotaxin for the DA model. The BLR and DA men-only models contained one cytokine each, eotaxin for BLR and platelet-derived growth factor-bb (PDGF-BB) for DA. We show that BLR has a higher fidelity in identifying RA patients than DA. We also found that the use of gender-specific models marginally improves detection fidelity, indicating a possible benefit in clinical diagnosis. More research is needed to determine whether this conclusion will hold true in various and larger patient populations.

Circadian Regulation of Macrophages and Osteoclasts in Rheumatoid Arthritis

Rheumatoid arthritis (RA) represents one of the best examples of circadian fluctuations in disease severity. Patients with RA experience stiffness, pain, and swelling in afflicted joints in the early morning, which tends to become milder toward the afternoon. This has been primarily explained by the higher blood levels of pro-inflammatory hormones and cytokines, such as melatonin, TNFα, IL-1, and IL-6, in the early morning than in the afternoon as well as insufficient levels of anti-inflammatory cortisol, which rises later in the morning. Clinical importance of the circadian regulation of RA symptoms has been demonstrated by the effectiveness of time-of-day-dependent delivery of therapeutic agents in chronotherapy. The primary inflammatory site in RA is the synovium, where increased macrophages, T cells, and synovial fibroblasts play central roles by secreting pro-inflammatory cytokines, chemokines, and enzymes to stimulate each other, additional immune cells, and osteoclasts, ultimately leading to cartilage and bone erosion. Among these central players, macrophages have been one of the prime targets for the study of the link between circadian rhythms and inflammatory activities. Gene knockout experiments of various core circadian regulators have established that disruption of any core circadian regulators results in hyper- or hypoactivation of inflammatory responses by macrophages when challenged by lipopolysaccharide and bacteria. Although these stimulations are not directly linked to RA etiology, these findings serve as a foundation for further study by providing proof of principle. On the other hand, circadian regulation of osteoclasts, downstream effectors of macrophages, remain under-explored. Nonetheless, circadian expression of the inducers of osteoclastogenesis, such as TNFα, IL-1, and IL-6, as well as the knockout phenotypes of circadian regulators in osteoclasts suggest the significance of the circadian control of osteoclast activity in the pathogenesis of RA. More detailed mechanistic understanding of the circadian regulation of macrophages and osteoclasts in the afflicted joints could add novel local therapeutic options for RA.

Can pyroptosis be a new target in rheumatoid arthritis treatment?

Rheumatoid arthritis (RA) is a chronic systemic autoimmune disease of undefined etiology, with persistent synovial inflammation and destruction of articular cartilage and bone. Current clinical drugs for RA mainly include non-steroidal anti-inflammatory drugs (NSAIDs), glucocorticoids, disease modifying anti-rheumatic drugs (DMARDs) and so on, which can relieve patients' joint symptoms. If we want to have a complete cure for RA, there are still some limitations of these drugs. Therefore, we need to explore new mechanisms of RA to prevent and treat RA radically. Pyroptosis is a newly discovered programmed cell death (PCD) in recent years, which is characterized by the appearance of holes in cell membranes, cell swelling and rupture, and the release of intracellular pro-inflammatory factors into the extracellular space, resulting in a strong inflammatory response. The nature of pyroptosis is pro-inflammatory, and whether it is participating in the development of RA has attracted a wide interest among scholars. This review describes the discovery and mechanism of pyroptosis, the main therapeutic strategies for RA, and the role of pyroptosis in the mechanism of RA development. From the perspective of pyroptosis, the study of new mechanisms of RA may provide a potential target for the treatment of RA and the development of new drugs in the clinics.

In vitro and in vivo anti-inflammatory and anti-arthritic effect of Tinospora cordifolia via modulation of JAK/STAT pathway

BACKGROUND

Rheumatoid arthritis (RA) is a chronic inflammatory disorder causing cartilage and joint degeneration. In spite of the availability of several robust drugs like biologics, most of the patients are unresponsive, and reports of severe adverse effects following long-term use are also there. Subsequently the use of natural plant-based products in RA therapy is broadening over the years. Tinospora cordifolia is a widely used medicinal plant in Ayurveda against various inflammatory disorders including RA. However, there is very limited knowledge regarding the actual molecular events responsible for its therapeutic effect, and this has limited its acceptance among the professionals.

PURPOSE

To explore the anti-inflammatory and anti-arthritic effect of hydro-alcoholic extract from Tinospora cordifolia.

METHODS

The rich polyphenol nature of the extract was elucidated using HPLC. LPS-stimulated murine macrophage cell line RAW 264.7 was used for in vitro studies, and collagen-induced arthritis (CIA) model was used for in vivo studies.

RESULTS

The polyphenols in TCE were identified using HPLC. TCE effectively downregulated the level of pro-inflammatory mediators (IL-6, TNF-α, PGE2, and NO) in LPS-stimulated RAW 264.7 cells. Subsequently the upregulated expression of COX-2 and iNOS following LPS stimulation were also downregulated by TCE. Furthermore, TCE targeted the upstream kinases of the JAK/STAT pathway, a crucial inflammatory pathway. The expression of VEGF, a key angiogenic factor as well as an inflammatory mediator was also decreased following pre-treatment with TCE. The anti-arthritic effect of TCE (150 mg/kg) was evaluated in the CIA model as well. From the results of histopathology, oral administration of TCE was found to be effective in reducing the clinical symptoms of arthritis including paw edema, erythema, and hyperplasia. In vivo results validated the in vitro results and there was a significant reduction in serum level of pro-inflammatory cytokines and mediators (IL-6, TNF-α, IL-17, NO, and PGE2). The phosphorylation of STAT3 and the expression of VEGF were also downregulated following TCE treatment.

CONCLUSION

Our study provided a detailed insight into the molecular events associated with anti-inflammatory and anti-arthritic effect of Tinospora cordifolia.

MicroRNAs-mediated regulation pathways in rheumatic diseases

Rheumatoid arthritis (RA) and ankylosing spondylitis (AS) are two common rheumatic disorders marked by persistent inflammatory joint disease. Patients with RA have osteodestructive symptoms, but those with AS have osteoproliferative manifestations. Ligaments, joints, tendons, bones, and muscles are all affected by rheumatic disorders. In recent years, many epigenetic factors contributing to the pathogenesis of rheumatoid disorders have been studied. MicroRNAs (miRNAs) are small, non-coding RNA molecules implicated as potential therapeutic targets or biomarkers in rheumatic diseases. MiRNAs play a critical role in the modulation of bone homeostasis and joint remodeling by controlling fibroblast-like synoviocytes (FLSs), chondrocytes, and osteocytes. Several miRNAs have been shown to be dysregulated in rheumatic diseases, including miR-10a, 16, 17, 18a, 19, 20a, 21, 27a, 29a, 34a, 103a, 125b, 132, 137, 143, 145, 146a, 155, 192, 203, 221, 222, 301a, 346, and 548a.The major molecular pathways governed by miRNAs in these cells are Wnt, bone-morphogenic protein (BMP), nuclear factor (NF)-κB, receptor activator of NF-κB (RANK)-RANK ligand (RANKL), and macrophage colony-stimulating factor (M-CSF) receptor pathway. This review aimed to provide an overview of the most important signaling pathways controlled by miRNAs in rheumatic diseases.

Metabolic reprogramming in Rheumatoid Arthritis Synovial Fibroblasts: A hybrid modeling approach

Rheumatoid Arthritis (RA) is an autoimmune disease characterized by a highly invasive pannus formation consisting mainly of Synovial Fibroblasts (RASFs). This pannus leads to cartilage, bone, and soft tissue destruction in the affected joint. RASFs' activation is associated with metabolic alterations resulting from dysregulation of extracellular signals' transduction and gene regulation. Deciphering the intricate mechanisms at the origin of this metabolic reprogramming may provide significant insight into RASFs' involvement in RA's pathogenesis and offer new therapeutic strategies. Qualitative and quantitative dynamic modeling can address some of these features, but hybrid models represent a real asset in their ability to span multiple layers of biological machinery. This work presents the first hybrid RASF model: the combination of a cell-specific qualitative regulatory network with a global metabolic network. The automated framework for hybrid modeling exploits the regulatory network's trap-spaces as additional constraints on the metabolic network. Subsequent flux balance analysis allows assessment of RASFs' regulatory outcomes' impact on their metabolic flux distribution. The hybrid RASF model reproduces the experimentally observed metabolic reprogramming induced by signaling and gene regulation in RASFs. Simulations also enable further hypotheses on the potential reverse Warburg effect in RA. RASFs may undergo metabolic reprogramming to turn into "metabolic factories", producing high levels of energy-rich fuels and nutrients for neighboring demanding cells through the crucial role of HIF1.

CD169+ Monocyte and Regulatory T Cell Subsets Are Associated with Disease Activity in Rheumatoid Arthritis

Disease activity in rheumatoid arthritis (RA) is influenced by activation of circulating and synovial immune cells. Regulatory T cells (Tregs) and monocytes are key cells that drive inflammation in RA. This study investigated if a relationship exists between disease activity in RA and circulating Treg and monocyte numbers and phenotypes. A potential sialic acid (Sia) mediated link between Tregs and monocytes was also probed in vitro. Peripheral blood mononuclear cells (PBMCs) were isolated from RA patient (n = 62) and healthy control (n = 21) blood using density gradient separation. Flow cytometry was used to count and phenotype Treg and monocyte subsets, and to sort healthy control Tregs for Sia cell culture experiments. The effects of Sia on activated Treg FoxP3 and NFκB expression was assessed by flow cytometry and concentrations of secreted TNFα, IL-10 and IFNγ determined by ELISA. High disease activity RA patients who were unresponsive to disease modifying anti-rheumatic drugs (n = 31), have significantly lower relative numbers (percentages) of CD4+CD25+CD127− Tregs (p < 0.01) and memory CD45RA−FoxP3+ Tregs (p < 0.01), compared to low disease activity responders (n = 24). Relative numbers of non-classical CD169+ monocytes are associated with disease activity in RA (p = 0.012). Sia reduced Treg expression of FoxP3, NFκB and cytokines in vitro. A strong association has been identified between non-classical CD169+ monocytes and post-treatment disease activity in RA. This study also indicates that Sia can reduce Treg activation and cytokine release. We postulate that such a reduction could be mediated by interaction with sialyted proteins captured by CD169+ monocytes.

Harpagoside attenuates local bone Erosion and systemic osteoporosis in collagen-induced arthritis in mice

Background

Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease that causes local bone erosion and systemic osteoporosis. Harpagoside (HAR), an iridoid glycoside, has various pharmacological effects on pain, arthritis, and inflammation. Our previous study suggests that HAR is more deeply involved in the mechanism of bone loss caused by inflammatory stimuli than hormonal changes. Here, we identified the local and systemic bone loss inhibitory effects of HAR on RA and its intracellular mechanisms using a type 2 collagen-induced arthritis (CIA) mouse model.

Methods

The anti-osteoporosis and anti-arthritic effects of HAR were evaluated on bone marrow macrophage in vitro and CIA in mice in vivo by obtaining clinical scores, measuring hind paw thickness and inflammatory cytokine levels, micro-CT and histopathological assessments, and cell-based assay.

Results

HAR markedly reduced the clinical score and incidence rate of CIA in both the prevention and therapy groups. Histological analysis demonstrated that HAR locally ameliorated the destruction of bone and cartilage and the formation of pannus. In this process, HAR decreased the expression of inflammatory cytokines, such as tumor necrosis factor-α, interleukin (IL)-6, and IL-1β in the serum of CIA mice. Additionally, HAR downregulated the expression of receptor activator of nuclear factor-κB ligand and upregulated that of osteoprotegerin. HAR suppressed systemic bone loss by inhibiting osteoclast differentiation and osteoclast marker gene expression in a CIA mouse model.

Conclusions

Taken together, these findings show the beneficial effect of HAR on local symptoms and systemic bone erosion triggered by inflammatory arthritis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12906-022-03694-y.

Evaluating the anti-arthritic potential of walnut (Juglans regia L.) in FCA induced Sprague Dawley rats

Rheumatoid arthritis (RA) is an autoimmune progressive disease, associated with many pathophysiological consequences. Owing to the adverse effects and higher costs of pharmaceuticals, people are now looking for complementary and alternative remedies. In this milieu, the present study was designed to explore the therapeutic potential of walnuts against FCA-induced arthritis in rat models. Purposely, 50 Sprague Dawley rats were housed in a well-ventilated animal room and separated into 5 groups of 10 rats each. The rats were categorized as G₀ (negative control), G₁ (positive control, i.e., FCA induced untreated arthritic rats), G₂ (arthritic rats treated with MTX), G₃ (arthritic rats treated with walnut feed), and G₄ (arthritic rats treated with walnut extract), with an efficacy trial lasting for 42 days. The physical analysis explicated that paw swelling was significantly improved by 10%-12.8% in treatment groups after the intervention when compared with positive control. Moreover, biochemical analyses revealed significantly lower levels of ESR, CRP, and RF in rats treated with walnut-based interventions when compared to positive control. ESR values were decreased by 62.4% and 69.92% in G₃ and G₄ , whereas CRP levels were improved by 56.20% and 77.78% in G₃ and G₄ when compared with G₁ . Likewise, RF values decreased in G₂ , G₃ , and G₄ by 64.71%, 55.88%, and 69.24%, respectively when compared to G₁ . The histological examination demonstrated the potential role of walnut-based interventions in reducing the severity of disease by decreasing cell infiltration, bone erosion, and paw inflammation. Meanwhile, the gene expression analysis revealed that walnut-based interventions protected the paw joints from damage by downregulating the RANKL-OPG pathway. Conclusively, walnut feed and extract may serve as potent anti-arthritic interventions with no side effects. PRACTICAL APPLICATIONS: Plant-based therapeutics are effective in the prevention and management of various chronic diseases. The current research explored the anti-arthritic potential of walnuts. Walnut feed and extract effectively reduced the serum arthritic biomarkers as well as downregulated the genes involved in bone destruction. Thus, the inclusion of dietary ingredients having therapeutic potential such as walnuts may be synchronized in clinical practices to ameliorate arthritis.

The Bioimpedance Phase Angle may be Associated With Frailty in Rheumatoid Arthritis Patients: Results From a Prospective, Cohort Study

OBJECTIVES

This study investigated whether the phase angle (PhA) on bioelectrical impedance analysis (BIA) is related to frailty in rheumatoid arthritis (RA) patients.

METHODS

Data from a prospective cohort study of RA patients were analyzed. The PhA was assessed by the BIA method, and frailty was assessed by the Kihon Check List (KCL) annually. The cutoff value of the PhA for frailty was calculated by receiver-operating characteristic analysis. The relationships between the PhA and frailty were evaluated by logistic regression analysis. The relationships between the change in PhA and frailty status and the KCL score were evaluated by analysis of covariance and multiple regression analysis.

RESULTS

A total of 170 patients (81.2% female, 66.2±13.1 years) were included in the analysis. A PhA of less than the cutoff for frailty was significantly associated with frailty (odds ratio: 4.75, 95% confidence interval: 1.86-12.17). Change in the PhA was significantly associated with change in the KCL score (β = -0.15). In robust patients, there was a significant difference in the rate of change of the PhA between the group that became pre-frail in the next year and the group that remained robust.

CONCLUSIONS

The PhA may be associated with frailty in RA patients.

The expression of zinc finger 804a (ZNF804a) and cyclin-dependent kinase 1 (CDK1) genes is related to the pathogenesis of rheumatoid arthritis

CONTEXT

ZNF804a and CDK1 genes code for proteins involved in inflammatory pathways.

OBJECTIVE

This study aimed to investigate the correlation of ZNF804a and CDK1 expression profiles in RA with the activity and the severity of the disease and to assess their association with inflammatory reactions in the Egyptian RA patients.

METHODS

ZNF804a and CDK1 expression profiles were assessed using quantitative PCR (qRT-PCR). Clinical and laboratory parameters were evaluated.

RESULTS

ZNF804a expression was down-regulated by 0.177-fold while CDK1 expression was up-regulated to 3.29-fold in RA patients compared with healthy controls (p < .001). ZNF804a down-regulation was negatively correlated with CRP, RF, disease activity score of 28 joints (DAS) using CRP (DAS-CRP) and TNF-α. CDK1 overexpression was correlated with IFN-1 and ACPA in RA patients.

CONCLUSION

ZNF804a and CDK1 genes are implicated in RA pathogenesis due to their influences on TNF-α and IFN-1 which contribute to inflammation in RA patients.

Rheumatoid Arthritis and JAK-STAT Inhibitors: Prospects of Topical Delivery

Abstract:

Rheumatoid arthritis (RA) is the most common musculoskeletal disease in the world. The clinical prospects have increased tremendously since the advent of biological agents as therapy options. NSAIDs such as indomethacin, celecoxib, and etoricoxib are used often in the treatment of RA but off-target effects decreased their use. DMARDs such as methotrexate and etanercept were also effective in the treatment of RA, but tolerance to methotrexate developed in many cases. Janus kinase inhibitors (JAKi) have also gained popularity as a treatment option for rheumatoid arthritis. Tofacitinib is the foremost JAK inhibitor that is used to treat RA as an individual agent or in combination with other DMARDs. The most frequently used route of administration for JAKi is oral. Since oral formulations of JAK inhibitors have a number of health hazards, such as systemic toxicity and patient noncompliance, topical formulations of JAK inhibitors have emerged as a preferable alternative for administering JAK inhibitors. Tofacitinib delivered topically, seems to have the potential to eliminate or reduce the occurrences of negative effects when compared to tofacitinib taken orally. Given the scarcity of knowledge on the techniques for topical distribution of JAKi, more effort will be required to develop a stable topical formulation of JAKi to address the limitations of oral route. The current review looks at JAK inhibitors and the ways that have been used to generate topical formulations of them.

Role of TNF-α in early-stage fracture healing under normal and diabetic conditions

BACKGROUND AND OBJECTIVE

Inflammatory response plays a crucial role in the early stage of fracture healing. Immediately after fracture, the debris and immune cells (e.g., macrophages), recruited into the fracture callus, lead to the secretion of inflammatory cytokines, such as tumor necrosis factor-alpha (TNF-α), which governs the mesenchymal stem cells (MSCs) mediated healing processes. However, it is still unclear how chronic inflammatory diseases (e.g., diabetes) affect the level of TNF-α in fracture callus, ultimately the healing outcomes at the early stage of healing. Therefore, the purpose of this study is to develop a numerical model for investigating TNF-α mediated bone fracture healing.

METHODS

A mathematical model consisting of a system of partial differential equations that represent the reactive transport of cells and cytokines in the fracture callus is developed in this study. The model is first calibrated by using available experimental data and then implemented to study the effect of TNF-α on the early stage of fracture healing under normal and diabetic conditions.

RESULTS

There is a significant elevation of TNF-α level in facture callus during the first 24 h post-fracture in normal condition, and its influence in the concentration of MSCs and cell differentiation becomes significant three days post-fracture (e.g., the absence of TNF-α signaling could reduce the concentration of MSCs more than 20% in cortical callus). In addition, the excessive secretion of TNF-α induced by diabetes could decrease the concentration of MSCs at the initial stage of healing, particularly reduce the concentration of MSCs in cortical callus by around 25%.

CONCLUSION

The model predictions suggested that there should be an optimal concentration of TNF-α in fracture callus, which enhances the early stage of healing, and excessive or insufficient secretion of TNF-α might significantly hinder the healing process.

Metformin and its therapeutic applications in autoimmune inflammatory rheumatic disease

Metformin is a first-line therapeutic agent for type 2 diabetes. Apart from its glucose-lowering effect, metformin is attracting interest regarding possible therapeutic benefits in various other conditions. As metformin regulates cell metabolism, proliferation, growth, and autophagy, it may also modulate immune cell functions. Given that metformin acts on multiple intracellular signaling pathways, including adenosine monophosphate (AMP)-activated protein kinase (AMPK) activation, and that AMPK and its downstream intracellular signaling control the activation and differentiation of T and B cells and inflammatory responses, metformin may exert immunomodulatory and anti- inflammatory effects. The efficacy of metformin has been investigated in preclinical and clinical studies on rheumatoid arthritis, osteoarthritis, systemic lupus erythematosus, Sjögren's syndrome, scleroderma, ankylosing spondylitis, and gout. In this review, we discuss the potential mechanisms through which metformin exerts its therapeutic effects in these diseases, focusing particularly on rheumatoid arthritis and osteoarthritis.

Therapeutic potential of triptolide in autoimmune diseases and strategies to reduce its toxicity

With the increasing epidemiology of autoimmune disease worldwide, there is an urgent need for effective drugs with low cost in clinical treatment. Triptolide, the most potent bioactive compound from traditional Chinese herb Tripterygium Wilfordii Hook F, possesses immunosuppression and anti-inflammatory activity. It is a potential drug for the treatment of various autoimmune diseases, but its clinical application is still restricted due to severe toxicity. In this review, the pharmacodynamic effects and pharmacological mechanisms of triptolide in autoimmune diseases are summarized. Triptolide exerts therapeutic effect by regulating the function of immune cells and the expression of cytokines through inflammatory signaling pathways, as well as maintaining redox balance and gut microbiota homeostasis. Meanwhile, the research progress on toxicity of triptolide to liver, kidney, reproductive system, heart, spleen, lung and gastrointestinal tract has been systematically reviewed. In vivo experiments on different animals and clinical trials demonstrate the dose- and time- dependent toxicity of triptolide through different administration routes. Furthermore, we focus on the strategies to reduce toxicity of triptolide, including chemical structural modification, novel drug delivery systems, and combination pharmacotherapy. This review aims to reveal the potential therapeutic prospect and limitations of triptolide in treating autoimmune diseases, thus providing guiding suggestions for further study and promoting its clinical translation.

Exploring the Extracellular Vesicle MicroRNA Expression Repertoire in Patients with Rheumatoid Arthritis and Ankylosing Spondylitis Treated with TNF Inhibitors

Rheumatoid arthritis (RA) and ankylosing spondylitis (AS) belong to the most common inflammatory rheumatic diseases. MicroRNAs (miRNAs) are small 18–22 RNA molecules that function as posttranscriptional regulators. They are abundantly present within extracellular vesicles (EVs), small intercellular communication vesicles that can be found in bodily fluids and that have key functions in pathological and physiological pathways. Recently, EVs have gained much interest because of their diagnostic and therapeutic potential. Using NanoString profiling technology, the miRNA repertoire of serum EVs was determined and compared in RA and AS patients before and after anti-TNF therapy to assess its potential use as a diagnostic and prognostic biomarker. Furthermore, possible functional effects of those miRNAs that were characterized by the most significant expression changes were evaluated using in silico prediction algorithms. The analysis revealed a unique profile of differentially expressed miRNAs in RA and AS patient serum EVs. We identified 12 miRNAs whose expression profiles enabled differentiation between RA and AS patients before induction of anti-TNF treatment, as well as 4 and 14 miRNAs whose repertoires were significantly changed during the treatment in RA and AS patients, respectively. In conclusion, our findings suggest that extracellular vesicle miRNAs could be used as potential biomarkers associated with RA and AS response to biological treatment.

Majoon Chobchini attenuates arthritis disease severity and RANKL-mediated osteoclastogenesis in rheumatoid arthritis

Majoon Chobchini, a polyherbal Unani compound, has been used holistically in India to treat rheumatoid arthritis. However, the potential mechanism underlying the antiarthritic efficacy of Majoon Chobchini has not been elucidated so far. This study was aimed to explore the underlying molecular mechanism and scientifically validate the therapeutic basis of Majoon Chobchini in rheumatoid arthritis (RA). The anti-arthritic efficacy of Majoon Chobchini was demonstrated in vivo using complete Freund's adjuvant-induced arthritic rat model and adjuvant-induced arthritic fibroblast-like synoviocytes (AA-FLS). The expression of pro-inflammatory mediators and enzymes was evaluated in the serum and synovial tissues of adjuvant-induced arthritis (AIA) rats. In-vitro, AA-FLS, and bone marrow macrophages (BMMs) were co-cultured to evaluate the formation and activity of osteoclasts using TRAP staining analysis and pit formation assay, respectively. RANKL and OPG levels were detected using western blotting and qRT-PCR analysis. Furthermore, the involvement of JAK-STAT-3 signaling in the therapeutic efficacy of Majoon Chobchini was evaluated both in vivo and in vitro. Majoon Chobchini significantly reversed the physical symptoms in AIA rats with reduced expression of pro-inflammatory cytokines and enzymes. Notably, Majoon Chobchini alleviated cartilage degradation and bone erosion in AIA rats via inhibiting the activation of the JAK-STAT-3 signaling pathway in the AIA rats. Consistent with its effect in vivo, Majoon Chobchini decreased osteoclast inducing potential of AA-FLS and thus attenuated osteoclast formation and bone resorption in vitro. Taken together, our findings suggest that the JAK/STAT-3 signaling inhibition may underlie the mechanism through which Majoon Chobchini provides relief against RA symptoms.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s13205-021-02985-4.

Sulfonylureas for Treatment of Periodontitis-Diabetes Comorbidity-Related Complications: Killing Two Birds With One Stone

Periodontitis is one of the most prevalent oral inflammatory diseases leading to teeth loss and oral health problems in adults. Periodontitis mainly affects periodontal tissue by affecting the host immune system and bone homeostasis. Moreover, periodontitis is associated with various systemic diseases. Diabetes is a metabolic disease with systemic effects. Both periodontitis and diabetes are common inflammatory diseases, and comorbidity of two diseases is linked to exacerbation of the pathophysiology of both diseases. Since bacterial dysbiosis is mainly responsible for periodontitis, antibiotics are widely used drugs to treat periodontitis in clinics. However, the outcomes of antibiotic treatments in periodontitis are not satisfactory. Therefore, the application of anti-inflammatory drugs in combination with antibiotics could be a treatment option for periodontitis-diabetes comorbidity. Anti-diabetic drugs usually have anti-inflammatory properties and have shown beneficial effects on periodontitis. Sulfonylureas, insulin secretagogues, are the earliest and most widely used oral hypoglycemic drugs used for type-2 diabetes. Studies have found that sulfonylurea drugs can play a certain role in the mitigation of periodontitis and inflammation. This article reviews the effects of sulfonylurea drugs on the mitigation of periodontitis-diabetes comorbidity-related inflammation, bone loss, and vascular growth as well as the involved molecular mechanisms. We discuss the possibility of a new application of sulfonylureas (old drug) to treat periodontitis-diabetes comorbidity.

Halofuginone functions as a therapeutic drug for chronic periodontitis in a mouse model

Periodontitis is an inflammatory disease caused by host immune response, resulting in a loss of periodontium and alveolar bone. Immune cells, such as T cells and macrophages, play a critical role in the periodontitis onset. Halofuginone, a natural quinazolinone alkaloid, has been shown to possess anti-fibrosis, anti-cancer, and immunomodulatory properties. However, the effect of halofuginone on periodontitis has never been reported. In this study, a ligature-induced mice model of periodontitis was applied to investigate the potential beneficial effect of halofuginone on periodontitis. We demonstrated that the administration of halofuginone significantly reduced the expression levels of pro-inflammatory cytokines (IL-1β, IL-6, and TNF-α) in vivo, and markedly suppressed immune cell infiltration into the infected sites. Furthermore, we also observed that halofuginone treatment blocked the T-helper 17 (Th17) cell differentiation in vivo and in vitro. We demonstrated for the first time that halofuginone alleviated the onset of periodontitis through reducing immune responses.

Adenosine deaminase modulates metabolic remodeling and orchestrates joint destruction in rheumatoid arthritis

Rheumatoid Arthritis (RA) is a chronic autoimmune disease associated with inflammation and joint remodeling. Adenosine deaminase (ADA), a risk factor in RA, degrades adenosine, an anti-inflammatory molecule, resulting in an inflammatory bias. We present an integrative analysis of clinical data, cytokines, serum metabolomics in RA patients and mechanistic studies on ADA-mediated effects on in vitro cell culture models. ADA activity differentiated patients into low and high ADA sets. The levels of the cytokines TNFα, IFNγ, IL-10, TGFβ and sRANKL were elevated in RA and more pronounced in high ADA sets. Serum metabolomic analysis shows altered metabolic pathways in RA which were distinct between low and high ADA sets. Comparative analysis with previous studies shows similar pathways are modulated by DMARDs and biologics. Random forest analysis distinguished RA from control by methyl-histidine and hydroxyisocaproic acid, while hexose-phosphate and fructose-6-phosphate distinguished high ADA from low ADA. The deregulated metabolic pathways of High ADA datasets significantly overlapped with high ADA expressing PBMCs GEO transcriptomics dataset. ADA induced the death of chondrocytes, synoviocyte proliferation, both inflammation in macrophages and their differentiation into osteoclasts and impaired differentiation of mesenchymal stem cells to osteoblasts and mineralization. PBMCs expressing elevated ADA had increased expression of cytokines and P2 receptors compared to synovial macrophages which has low expression of ADA. Our data demonstrates increased cytokine levels and distinct metabolic signatures of RA based on the ADA activity, suggests an important role for ADA in the pathophysiology of RA joints and as a potential marker and therapeutic target in RA patients.

The maximum dose and duration in the therapy single use methotrexate to achieve remission by rheumatoid arthritis patients through disease activity score 28 (DAS28)

OBJECTIVES

One of the treatments for rheumatoid arthritis (RA) was methotrexate which a disease modifying antirheumatic drug therapy. The use of methotrexate required the right dose and length of therapy to achieve remission. The effectivity of methotrexate could be accounted by disease activity score 28 (DAS28) as a tool has been used clinically with a combination number of tender joints, swollen joints, erythrocyte sedimentation rate, and global clinical assessment by the patient. The aim of this study was to determine the effective dose and length of therapy methotrexate was measured by DAS28 score.

METHODS

This research was a cross-sectional study and data was collected from patient medical records in Saiful Anwar Hospital, Malang, from February to July 2018. The research has been given ethical clearance. The inclusion criteria for the 88 subjects were men and women, over 20 years of age, usage of only methotrexate for at least three months, an erythrocyte sedimentation rate score, uncomplicated inflammatory bowel disease, cancer, and systemic lupus erythematosus. All data obtained was entered in formula DAS28. The Statistic analysis used both Pearson and Spearman's rank correlation.

RESULTS

Only 16 patients achieved remission. There were not significant correlation in statistical analysis between DAS score and cumulative dose (r=-0.091; p=0.400), average dose (r=0.043; p = 0.692), maximum dose (r=0.074; p=0.492), and length of therapy (r=-0.075; p = 0.489). The initial dose of therapy methotrexate was different and the length of therapy was adjusted to the patient's health condition.

CONCLUSIONS

The maximum dose and length of therapy methotrexate was required to achieve remission in RA.

Sparstolonin B Exerts Therapeutic Effects on Collagen-Induced Arthritis by Inhibiting the NLRP3 Inflammasome and Reducing the Activity of α1,3-Fucosyltransferase

Objective. To explore the role of α1,3-fucosyltransferase in the mediation of rheumatoid arthritic inflammation, the protective effect of Sparstolonin B on rheumatoid arthritis (RA), and the mechanisms that regulate the NLRP3 inflammasome. Methods. Forty, weighing from 260-300 g, male Sprague-Dawley rats were randomly divided into the following groups: a sham operation group (Sham group), a rheumatoid arthritis model group (RA group), an RA+Sparstolonin B treatment group (RAS group), an RA+Iguratimod group (RAI group), and an RA+SsnB+NLRP3 inflammasome activator (Nigericin) group (RASN group); ten animals were allocated to each group. We determined the arthritis index for each group of rats, and pathological changes were evaluated by hematoxylin-eosin staining. We also used ELISAs to determine the serum levels of IL-17, IL-6, TNF-α, TGF-β, IL-18, and IL-1β. TUNEL staining was used to investigate apoptosis in synovial cells. IF was used to detect the release of ROS, ASC formation, and the expression levels of FucT-V and NLRP3. Western blotting was used to detect the protein expression levels of Bc1-2, Bax, TLR4, MYD88, NF-κB, pro-caspase-1, NLRP3, FucT-V, E-Selectin, and P-Selectin. We also performed in vitro experiments with Sparstolonin B and detected changes in 1,3-fucosyltransferase activity by ELISA. The pyroptosis-related phenotype, including ASC, was identified by immunofluorescence, while levels of NLRP-3, pro-IL-1, and pro-caspase-1 were detected by western blotting. Results. Sparstolonin B was showed to alleviate joint swelling in RA rats, inhibited inflammatory cell infiltration and the release of ROS, reduced damage caused by oxidative stress, and suppressed the rate of apoptosis in synovial cells. The administration of Sparstolonin B inhibited the secretion of IL-17 from Th17 cells and triggered the secretion of TGF-β from Treg cells, thus leading to the reduced expression of TLR4, MyD88, and NF-κB, and the suppression of TNF-α secretion. Moreover, Sparstolonin B downregulated the expression of NLRP3, inhibited ASC formation in vivo and in vitro, and reduced the levels of IL-18 and IL-1β. The expression levels of FucT-V, E-Selectin, and P-Selectin were also inhibited. Interestingly, these protective effects of Sparstolonin B could be blocked in RA rats by inhibiting the activation of the NLRP3 inflammasome. Conclusion. Sparstolonin B improved inflammatory responses and oxidative stress by inhibiting the NLRP3 inflammasome, inhibiting the expression of FucT-V and downregulating the TLR4/MYD88/NF-𝜅B signaling pathway in order to rescue RA.

Comprehensive in vitro comparison of cellular and osteogenic response to alternative biomaterials for spinal implants

A variety of novel biomaterials are emerging as alternatives to conventional metals and alloys, for use in spinal implants. These promise potential advantages with respect to e.g. elastic modulus compatibility with the host bone, improved radiological imaging or enhanced cellular response to facilitate osseointegration. However, to date there is scarce comparative data on the biological response to many of these biomaterials that would give insights into the relative level of bone formation, resorption inhibition and inflammation. Thus, in this study, we aimed to evaluate and compare the in vitro biological response to standard discs of four alternative biomaterials: polyether ether ketone (PEEK), zirconia toughened alumina (ZTA), silicon nitride (SN) and surface-textured silicon nitride (ST-SN), and the reference titanium alloy Ti6Al4V (TI). Material-specific characteristics of these biomaterials were evaluated, such as surface roughness, wettability, protein adsorption (BSA) and apatite forming capacity in simulated body fluid. The activity of pre-osteoblasts seeded on the discs was characterized, by measuring viability, proliferation, attachment and morphology. Then, the osteogenic differentiation of pre-osteoblasts was compared in vitro from early to late stage by Alizarin Red S staining and real-time PCR analysis. Finally, osteoclast activity and inflammatory response were assessed by real-time PCR analysis. Compared to TI, all other materials generally demonstrated a lower osteoclastic activity and inflammatory response. ZTA and SN showed generally an enhanced osteogenic differentiation and actin length. Overall, we could show that SN and ST-SN showed a higher osteogenic effect than the other reference groups, an inhibitive effect against bone resorption and low inflammation, and the results indicate that silicon nitride has a promising potential to be developed further for spinal implants that require enhanced osseointegration.

The emerging role of Interleukin 37 in bone homeostasis and inflammatory bone diseases

Interleukin 37 (IL-37) is a newly identified cytokine that belongs to the IL-1 family. Unlike other members of the IL-1 family, it has been demonstrated that IL-37 possesses anti-inflammatory characteristics in both innate and acquired immune responses. Recently, significant progress has been made in understanding the role of IL-37 in inflammatory signaling pathways. Meanwhile, IL-37 has also attracted more and more attention in bone homeostasis and inflammatory bone diseases. The latest studies have revealed that IL-37 palys an essential role in the regulation of osteoclastogenesis and osteoblastogenesis. The levels of IL-37 are abnormal in patients with inflammatory bone diseases such as rheumatoid arthritis (RA), osteoarthritis (OA), ankylosing spondylitis (AS), and periodontitis. In addition, in vivo studies have further confirmed that recombinant IL-37 treatment displayed therapeutic potential in these diseases. The present review article aims to provide an overview describing the biological functions of IL-37 in bone homeostasis and inflammatory bone diseases, thus shedding new light on a novel therapeutic strategy in the future.

Blocking TNFα attenuates progressive cartilage matrix degradation in inflammatory arthritis

Because damage to hyaline cartilage is irreversible, relieving progressive cartilage destruction is an important therapeutic approach for inflammatory arthritis. In the present study, human hyaline chondrocytes were isolated from total knee replacements of 15 patients with osteoarthritis (OA) and three with rheumatoid arthritis (RA). Synovial fluid of OA (n=25) and RA (n=34) were collected to measure tumor necrosis factor α (TNFα) using ELISA. Consistent with previous studies, the synovial fluid exhibited high TNFα levels and hyaline cartilage was severely destroyed in patients with RA. TNFα-treated chondrocytes were used as model for inflammatory arthritis. TNFα did not influence proliferation or extracellular matrix expression in chondrocytes, but induced matrix metalloproteinase (MMP)1, 3 and 13 expression levels in chondrocytes, which was accompanied by activation of nuclear factor-κB signaling. During chondrogenic differentiation, TNFα attenuated mRNA expression levels of anabolic factors (collagen type 2 and aggrecan) and enhanced mRNA expression of catabolic factors (MMP1, MMP3 and MMP13) in chondrocytes. Moreover, anti-TNFα agents (Golimumab) inhibited the TNFα-induced metabolic shift in chondrocytes and chondrogenic differentiation. The present study revealed a mechanism by which TNFα may induce metabolic shift in chondrocytes, leading to progressive chondrocyte destruction.

Double-blinded randomized controlled trial to reveal the effects of Brazilian propolis intake on rheumatoid arthritis disease activity index; BeeDAI

Background and aims

Brazilian propolis reportedly contributed to suppressing disease activity in a mouse model of rheumatoid arthritis (RA), suggesting new treatment options using Brazilian propolis. However, only results from animal experiments have been available, and the suppressive effects of Brazilian propolis on disease activity in humans with RA remain unknown. The purpose of this study was to clinically validate how Brazilian propolis intake changes disease activity in RA patients.

Methods

This study was conducted as a multicenter, double-blinded, randomized, placebo-controlled, parallel-group study of 80 women with RA (median age, 61.5 years; interquartile range, 56.0 to 67.3 years) showing moderate disease activity on Disease Activity Score in 28 joints using erythrocyte sedimentation rate (DAS28-ESR). Test tablets containing Brazilian propolis were used in Group P (40 patients), and Brazilian propolis-free placebo tablets were used as control in Group C (40 patients). Group P received 5 tablets of propolis (508.5 mg of propolis) daily, and Group C received 5 tablets of placebo daily. The intervention lasted 24 weeks, with change in DAS28-ESR set as the primary endpoint. As secondary endpoints, other disease activity assessment (DAS28 using C-reactive protein, simplified disease activity index, clinical disease activity index), ultrasonographic evaluation of synovitis, activities of daily living, quality of life, changes in cytokine levels, and adverse events over the course of the study were also assessed. Data were statistically analyzed by analysis of covariance.

Results

No significant differences in the primary endpoint were identified between groups (Group P vs Group C, effect: 0.14, 95% confidence interval: -0.21 to 0.49, p = 0.427). Likewise, no significant differences were seen between groups for any secondary endpoints. The adverse event rate during the study period was 28% in Group P and 33% in Group C.

Conclusions

Brazilian propolis exerted no effects on disease activity in patients with RA.

A double-blind, double-dummy, randomized controlled, multicenter trial of 99Tc-methylene diphosphonate in patients with moderate to severe rheumatoid arthritis

Background:

Clinical observational studies revealed that ⁹⁹Tc-methylene diphosphonate (⁹⁹Tc-MDP) could reduce joint pain and swollenness in rheumatoid arthritis (RA) patients. This multicenter, randomized, double-blind, double-dummy study aimed to evaluate the effects of ⁹⁹Tc-MDP plus methotrexate (MTX) vs. MTX alone or ⁹⁹Tc-MDP alone on disease activity and structural damage in MTX-naïve Chinese patients with moderate to severe RA.

Methods:

Eligible patients with moderate to severely active RA were randomized to receive ⁹⁹Tc-MDP plus MTX (n = 59) vs. MTX (n = 59) alone or ⁹⁹Tc-MDP (n = 59) alone for 48 weeks from six study sites across four provinces in China. The primary outcomes were the American College of Rheumatology 20% improvement (ACR20) response rates at week 24 and changes in modified total Sharp score at week 48.

Results:

At week 24, the proportion of participants achieving ACR20 was significantly higher in the MTX + ⁹⁹Tc-MDP combination group (69.5%) than that in the MTX group (50.8%) or ⁹⁹Tc-MDP group (47.5%) (P = 0.03 for MTX + ⁹⁹Tc-MDP vs. MTX, and MTX + ⁹⁹Tc-MDP vs.⁹⁹Tc-MDP, respectively). The participants in the MTX + ⁹⁹Tc-MDP group and the ⁹⁹Tc-MDP group had significantly less important radiographic progression than the participants in the MTX group over the 48 weeks (MTX + ⁹⁹Tc-MDP vs. MTX: P = 0.03, ⁹⁹Tc-MDP vs. MTX: P = 0.03, respectively). There was no significant difference in terms of adverse events (AEs) among the groups. No serious AEs were observed.

Conclusions:

This study demonstrated that the combination of ⁹⁹Tc-MDP with MTX inhibited structural damage and improved disease activity in RA patients compared with MTX and ⁹⁹Tc-MDP monotherapies, without increasing the rate of AEs. Additional clinical studies of ⁹⁹Tc-MDP therapy in patients with RA are warranted.

Trial Registration:

Chictr.org, ChiCTR-IPR-14005684; http://www.chictr.org.cn/showproj.aspx?proj=10088.

Metal-induced delayed type hypersensitivity responses potentiate particle induced osteolysis in a sex and age dependent manner

It is widely recognized that innate macrophage immune reactions to implant debris are central to the inflammatory responses that drive biologic implant failure over the long term. Less common, adaptive lymphocyte immune reactions to implant debris, such as delayed type hypersensitivity (DTH), can also affect implant performance. It is unknown which key patient factors, if any, mediate these adaptive immune responses that potentiate particle/macrophage mediated osteolysis. The objective of this investigation was to determine to what degree known adaptive immune responses to metal implant debris can affect particle-induced osteolysis (PIO); and if this pathomechanism is dependent on: 1) innate immune danger signaling, i.e., NLRP3 inflammasome activity, 2) sex, and/or 3) age. We used an established murine calvaria model of PIO using male and female wild-type C57BL/6 vs. Caspase-1 deficient mice as well as young (12–16 weeks old) vs. aged (18–24 months old) female and male C57BL/6 mice. After induction of metal-DTH, and Cobalt-alloy particle (ASTM F-75, 0.4um median diameter) calvaria challenge, bone resorption was assessed using quantitative micro-computed tomography (micro-CT) analysis and immune responses were assessed by measuring paw inflammation, lymphocyte transformation test (LTT) reactivity and adaptive immune cytokines IFN-gamma and IL-17 (ELISA). Younger aged C57BL/6 female mice exhibited the highest rate and severity of metal sensitivity lymphocyte responses that also translated into higher PIO compared to any other experimental group. The absence of inflammasome/caspase-1 activity significantly suppressed DTH metal-reactivity and osteolysis in both male and female Caspase-1 deficient mice. These murine model results indicate that young female mice are more predisposed to metal-DTH augmented inflammatory responses to wear debris, which is highly influenced by active NLRP3 inflammasome/caspase-1 danger signaling. If these results are clinically meaningful for orthopedic patients, then younger female individuals should be appropriately assessed and followed for DTH derived peri-implant complications.

Scientific validation of anti-arthritic effect of Kashayams - A polyherbal formulation in collagen induced arthritic rats

BACKGROUND

Toll-like receptor-4 (TLR-4) mediates activation of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) resulting in induction of proinflammatory genes such as that encoding tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) which played a significant role in cartilage destruction of rheumatoid arthritis (RA). Low risk and better efficacy made herbal drugs more reliable than nonsteroid anti-inflammatory drugs (NSAIDS) in RA treatment. Gugguluthiktam Kashayam (GuK), Punarnavadi Kashayam (PuK) and Balaguluchiadi Kashayam (BgK) are ayurvedic polyherbal formulations prescribed in classical ayurvedic texts Sahasrayogam and Ashtangahridayam as medicines for the treatment of RA.

OBJECTIVE

The objective of the present study was to elucidate the molecular mechanism of anti-arthritic effect of these Kashayams on TLR-4 signal transduction pathway in collagen induced arthritic rats.

MATERIAL AND METHODS

The wistar rats grouped into group I - Normal, group II- Collagen induced arthritis (CIA), group III- CIA + BgK, group IV- CIA + PuK, group V- CIA + GuK, group VI - CIA + Indomethacin (3 mg/kg b.wt.). Treatment with Kashayam (2 ml/kg b.wt) started after 14 days of primary immunization with type II collagen and continued for a period of 45 days.

RESULTS

Arthritis index, C-reactive protein (CRP), rheumatoid factor (RF) and myeloperoxidase (MPO) in serum and protein level of TLR-4, myeloid differentiation factor 88 (MYD88), NF-κB, TNF-α, IL-1β, inducible nitric oxide synthase (iNOS), cyclooxygenase-2 COX-2) and prostaglandin E-2 (PGE-2) in cartilage were significantly elevated in CIA rats. Further, treatment with Kashayams downregulated all these inflammatory mediators hitherto TLR-4-NF-kB signal transduction pathway except IL-10, an anti-inflammatory cytokine which showed a reverse effect.

CONCLUSION

This molecular mechanism of the investigation confirmed the clinical efficacy of Kashayams in preventing the progression of RA and gave an intuition of the scientific validation of Kashayams, an Ayurvedic classical medicine.

Pro-inflammatory cytokine response pre-dominates immuno-genetic pathway in development of rheumatoid arthritis

Rheumatoid arthritis (RA) is a crucial inflammatory joint disease characterized by loss of self-tolerance and severe cartilage loss, autoimmune, and subchondral bone erosions. Cytokines are the key regulators of inflammatory responses. Homeostatic imbalances in pro- and anti-inflammatory cytokine activities can result in pathogenic inflammatory reactions. These imbalances could be initiated by environmental factors but the ability to define the threshold of environmental impact relies on the genetic background of the pro- and anti-inflammatory cytokines. To address this a case-control association study was carried out in 429 individuals from Malayalam speaking ethnic population from South India. Functionally relevant SNPs from IL-10, IL-6, IL-1β and IL-1RN were genotyped using PCR -RFLP and sequencing. Meta-analysis was performed for the associated variants of IL-10, IL-1β. Significant association with RA was observed with IL-1β rs1143634, rs1143627, IL-10 rs1800896, IL-6 rs1800796, rs1800797. The associated SNPs are likely to impact transcriptional activity of a gene. Meta-analysis with global populations also provide evidence that IL-10 and IL-1β could be a global marker for RA. The functional significance of associated risk variants of IL-1β and IL-6 indicate increased production of the pro-inflammatory cytokines while IL-10 risk allele suggest reduced production of anti- inflammatory cytokines. The study concludes that increased production of pro-inflammatory cytokines and reduced production of anti- inflammatory cytokines may influence the Th1/Th2 equilibrium resulting in a triggering of Th1 mediated inflammatory responses in development of RA.

Visfatin and Rheumatoid Arthritis: Pathogenetic Implications and Clinical Utility

Objective:

Analysis and generalization of data related to visfatin involvement in the pathogenesis of inflammation at various stages of rheumatoid arthritis.

Data Synthesis:

Visfatin is an adipocytokine which has also been identified in non-adipose tissues. It influences directly on the maturation of B cells, which are involved in autoantibody production and T cell activation. Visfatin can promote inflammation via regulation of pro-inflammatory cytokines including TNF, IL-1β and IL-6. The concentration of circulating visfatin in rheumatoid arthritis patients is higher compared to healthy individuals. Several studies suggest that visfatin level is associated with rheumatoid arthritis activity, and its elevation may precede clinical signs of the relapse. In murine collagen-induced arthritis, visfatin levels were also found to be elevated both in inflamed synovial cells and in joint vasculature. Visfatin blockers have been shown to confer fast and long-term attenuation of pathological processes; however, most of their effects are transient. Other factors responsible for hyperactivation of the immune system can participate in this process at a later stage. Treatment of rheumatoid arthritis with a combination of these blockers and inhibitors of other mediators of inflammation can potentially improve treatment outcomes compared to current therapeutic strategies. Recent advances in the treatment of experimental arthritis in mice as well as the application of emerging treatment strategies obtained from oncology for rheumatoid arthritis management could be a source of novel adipokine-mediated anti-rheumatic drugs.

Conclusion:

The ongoing surge of interest in anticytokine therapy makes further study of visfatin highly relevant as it may serve as a base for innovational RA treatment.

THH Relieves CIA Inflammation by Reducing Inflammatory-related Cytokines

Tripterygium hypoglaucum hutch (THH) is a plant of the genus tripterygium, which is also known as colquhounia, Gelsemiun elegan, and so on. It is mainly distributed in Yunnan, Guizhou, and Sichuan regions and other places in China. To study the immune mechanism of THH on related inflammatory cytokines in collagen II-induced arthritis (CIA) mice, healthy male C57BL/6 mice were used to model CIA mice. Mice received THH 420 mg/kg/day or the same amount of normal saline (NS) by gavage for 20 days. The thickness of the ankle joint in mice was observed, and the arthritis index was calculated. Related inflammatory cytokines were detected by real-time quantitative polymerase chain reaction and enzyme-linked immunosorbent assay. The results showed that after treatment with THH, the CIA mice had less swelling and destruction of the joints as well as decreased foot size and arthritis index. The mRNA and protein levels of TNF-α, IFN-γ, and IL-17A were lower in the THH-treated group than in the NS group (P < 0.05). In summary, THH has great significance in the treatment of CIA mice, including reduced related inflammatory cytokines expression level in both joint tissue and serum. The mechanism of THH in the treatment of CIA may be through the inhibition of the NF-kB-STAT3-IL-17 pathway, which also requires further experimental investigation.

Sex-Based Differences in Monocytic Lineage Cells Contribute to More Severe Collagen-Induced Arthritis in Female Rats Compared with Male Rats

Monocytes' plasticity has an important role in the development of rheumatoid arthritis (RA), an autoimmune disease exhibiting greater prevalence in women. Contribution of this phenomenon to sex bias in RA severity was investigated in rat collagen-induced arthritis (CIA) model of RA. The greater severity of CIA in females (exhibiting signs of bone resorption) was accompanied by the higher blood level of advanced oxidation protein products and a more pro-oxidant profile. Consistently, in females, the greater density of giant multinuclear cells (monocytes/macrophages and osteoclasts) in inflamed joint tissue was found. This correlated with the higher frequencies of CCR2- and CX3CR1- expressing cells (precursors of inflammatory monocytes/macrophages and osteoclasts) among CD11b+ splenocytes. This in conjunction with the enhanced migratory capacity of CD11b+ monocytic cells in females compared with males could be linked with the higher frequencies of CCR2+CX3CR1-CD43^lowCD11b+ and CCR2-CX3CR1+CD43^hiCD11b+ cells (corresponding to "classical" and "non-classical" monocytes, respectively) and the greater density of CD68+ cells (monocytes/macrophages and osteoclast precursors/osteoclasts) in blood and inflamed paws from female rats, respectively. Consistently, the higher levels of GM-CSF, TNF-α and IL-6, IL-1β (driving Th17 cell differentiation), and IL-17 followed by the lower level of IL-10 were measured in inflamed paw cultures from female compared with male rats. To the greater IL-17 production (associated with enhanced monocyte immigration and differentiation into osteoclasts) most likely contributed augmented Th17 cell generation in the lymph nodes draining arthritic joints from female compared with male rats. Overall, the study suggests the sex-specific contribution of monocytic lineage cells to CIA, and possibly RA development.

Medicinal plants used against various inflammatory biomarkers for the management of rheumatoid arthritis

OBJECTIVES

Rheumatoid arthritis is a chronic autoimmune disease manifested clinically by polyarthralgia associated with joint dysfunction triggering the antibodies targeting against the self-neoepitopes determined by autoimmune responses associated with chronic arthritic attacks. The activation of macrophages and other defence cells in response to self-epitopes as biomarkers in RA provides a better understanding of pathogenesis of disease and has led to the development of novel therapeutic approaches acting as potent inhibitors of these cells.

KEY FINDINGS

The current review retrieved the various medicinal plants possessing an active phytoconstituents with anti-inflammatory and antioxidant properties, which tends to be effective alternative approach over the synthetic drugs concerned with high toxic effects. The current available literature provided an evident data concluding that the active constituents like fatty acids, flavonoids, terpenes and sesquiterpene lactones attenuate the RA symptoms by targeting the inflammatory biomarkers involved in the pathogenesis of RA.

SUMMARY

Despite the various synthetic treatment approaches targeting immune cells, cytokines improved the quality of life but still the drug management is challenging due to toxic and chronic teratogenic effects with anti-arthritic drugs. The current review has elaborated the selected traditionally used herbal medicinal plants with phytoconstituents possessing anti-inflammatory activity by suppressing the inflammatory biomarkers with lesser side effects and providing the future exploration of natural drug therapy for rheumatoid arthritis.

Estrogen downregulates TAK1 expression in human fibroblast-like synoviocytes and in a rheumatoid arthritis model

Transforming growth factor β-activated kinase-1 (TAK1), a member of the mitogen-activated protein kinase family, plays a key role in the pathogenesis and progression of rheumatoid arthritis (RA). Estrogen has been previously reported to delay arthritis progression. However, the exact association between TAK1 and estrogen remains elusive. The present study demonstrated that TAK1 was upregulated in synoviocytes of patients with RA compared with patients with osteoarthritis and healthy controls. In addition, TAK1 was also expressed in cultured fibroblast-like synoviocytes (FLS), and its levels decreased significantly in 17β-estradiol (E2)-treated cells in a dose-dependent manner. Furthermore, administration of E2 significantly decreased TAK1 expression and attenuated the development of collagen-induced arthritis (CIA). Taken together, the findings of the present study suggested that E2 mediates a decrease of TAK1 in both FLS and CIA, which subsequently results in a suppression of the pathological process of CIA. Therefore, estrogen may serve as a potential therapeutic agent for the treatment of RA by targeting TAK1.

Update on the Pathomechanism, Diagnosis, and Treatment Options for Rheumatoid Arthritis

Rheumatoid arthritis (RA) is an autoimmune disease that involves multiple joints bilaterally. It is characterized by an inflammation of the tendon (tenosynovitis) resulting in both cartilage destruction and bone erosion. While until the 1990s RA frequently resulted in disability, inability to work, and increased mortality, newer treatment options have made RA a manageable disease. Here, great progress has been made in the development of disease-modifying anti-rheumatic drugs (DMARDs) which target inflammation and thereby prevent further joint damage. The available DMARDs are subdivided into (1) conventional synthetic DMARDs (methotrexate, hydrochloroquine, and sulfadiazine), (2) targeted synthetic DMARDs (pan-JAK- and JAK1/2-inhibitors), and (3) biologic DMARDs (tumor necrosis factor (TNF)-α inhibitors, TNF-receptor (R) inhibitors, IL-6 inhibitors, IL-6R inhibitors, B cell depleting antibodies, and inhibitors of co-stimulatory molecules). While DMARDs have repeatedly demonstrated the potential to greatly improve disease symptoms and prevent disease progression in RA patients, they are associated with considerable side-effects and high financial costs. This review summarizes our current understanding of the underlying pathomechanism, diagnosis of RA, as well as the mode of action, clinical benefits, and side-effects of the currently available DMARDs.

Wang-Bi Capsule Alleviates the Joint Inflammation and Bone Destruction in Mice with Collagen-Induced Arthritis

Wang-Bi Capsule (WB), a traditional Chinese medicine- (TCM-) based herbal formula, is currently used in clinic for the treatment of rheumatoid arthritis (RA) with positive clinical effects. However, its pharmacological mechanism of action in RA is still obscure. Therefore, this study established a collagen-induced arthritis (CIA) mice model to examine the efficacy of WB by using arthritis score, histological analysis, and micro-CT examination. Proinflammatory cytokines expression, osteoclast number, OPG/RANKL system, and NF-κB activation were then detected to further investigate the mechanism of WB in RA treatment. The results indicated that WB could alleviate the erythema and swelling of paws in CIA mice. It also inhibited the infiltration of inflammatory cells and bone destruction and increased bone density in joints of CIA mice. Mechanistic studies showed that WB treatment decreased the production of IL-1β, IL-6, and TNF-α in serum and joints of CIA mice. Moreover, it reduced the osteoclast number, increased OPG level, decreased RANKL level, and inhibited the activation of NF-κB in joints of CIA mice. In conclusion, this study demonstrated that WB could effectively alleviate disease progression of CIA mice by decreasing the IL-1β, IL-6, and TNF-α levels, modulating the OPG/RANKL system, and inhibiting the activation of NF-κB.

Synergistic Effects of Erzhi Pill Combined With Methotrexate on Osteoblasts Mediated via the Wnt1/LRP5/β-Catenin Signaling Pathway in Collagen-Induced Arthritis Rats

Rheumatoid arthritis (RA) is a chronic systemic autoimmune disease characterized by chronic synovitis, bone erosion, and bone loss. Erzhi Pill (EZP), a classic Chinese patent medicine, is often used to treat osteoporosis and shows a capacity for bone metabolism regulation. Methotrexate (MTX), an essential drug for RA treatment, has been reported to inhibit generalized bone loss in RA patients. However, the combined therapeutic effects and mechanism of EZP and MTX in RA have not been fully elucidated. The aim of this study was to investigate the synergistic effect of EZP and MTX on RA and to explore the underlying mechanism through network pharmacological prediction and experimental verification. Chemical compounds of EZP, human target proteins of EZP and MTX, and RA-related human genes were identified in the Encyclopedia of Traditional Chinese Medicine database, PubChem database, and NCBI database, respectively. The molecular network of EZP and MTX in RA was generated and analyzed with Ingenuity Pathway Analysis software according to the datasets. Then, MTX monotherapy, EZP monotherapy, and combined MTX and EZP therapy were administered to collagen-induced arthritis rats, followed by assessment of pathological score, bone damage, bone alkaline phosphatases (BALP), and tartrate-resistant acid phosphatase (TRACP), and of gene levels related to the Wnt1/LRP5/β-catenin pathway according to network pharmacological analysis. Finally, serum samples from MTX-, EZP- and MTX+EZP-treated rats were used to treat the rat osteoblast (OB)-like UMR-106 cell line to evaluate gene levels related to Wnt1/LRP5/β-catenin. Network pharmacological analysis showed that the Wnt/β-catenin signaling pathway was the top signaling pathway shared among MTX, EZP, and RA. The results from in vivo experiments indicated that EZP combined with MTX reduced arthritis severity, alleviated ankle bone damage, increased BALP and decreased TRACP serum levels, and regulated the mRNA expression of Wnt1, LRP5, β-catenin, Runx2, BALP, and BGP in the ankles. In vitro experiments showed that EZP combined with MTX could also improve the expression of genes related to the Wnt1/LRP5/β-catenin pathway. This study demonstrated that EZP in combination with MTX played a synergistic role in regulating OBs in RA, which was connected to the modulatory effect of EZP and MTX on the Wnt1/LRP5/β-catenin signaling pathway.

Humulus japonicus extract ameliorates collagen‑induced arthritis in mice through regulation of overall articular inflammation

Humulus japonicus (HJ) is a widely used herbal medicine in Asia with anti-oxidative, anti-microbial, and anti-inflammatory effects. We investigated the potential therapeutic effects of HJ in rheumatoid arthritis (RA) using a mouse model of collagen-induced arthritis (CIA) and a lipopolysaccharide-stimulated murine macrophage cell line (RAW 264.7). The CIA mice were administered 300 mg/kg HJ orally starting 3 days prior to second immunization. The clinical and histopathological findings were assessed in the paw of CIA mice. The levels of autoantibodies and inflammatory markers were determined in the plasma and cell culture supernatant, respectively. The expression at mRNA and protein levels was analyzed by reverse transcription quantitative-PCR and western blot analysis, respectively. HJ significantly decreased the gross arthritic scores and paw swelling in CIA mice. Furthermore, synovial inflammation, cartilage destruction, and bone erosion were markedly reduced by HJ. It also decreased the expression of inflammatory enzymes in both the paw of mice and RAW 264.7 cells. Moreover, the expression of genes related to all macrophages and pro-inflammatory M1 macrophage were significantly decreased, whereas the expression of anti-inflammatory M2 macrophage marker was markedly increased in the paw of HJ-treated CIA mice. In addition, HJ suppressed the levels of plasma anti-type II collagen antibody following the decreased expression of T helper type 1 (Th1) and Th2 cell-associated surface markers and cytokines in the paw. HJ also significantly inhibited the expression of IL-6 both in vitro and in vivo, followed by reduced STAT3 phosphorylation and expression in the paw of CIA mice. Finally, the expression of osteoclast-related genes was decreased in the paw of HJ-treated CIA mice. These findings suggest that HJ can play a role in suppressing the development of CIA by overall regulation of articular inflammation. This study should provide new insights into the use of HJ as a therapeutically effective natural product against RA.

High LDL levels lessen bone destruction during antigen-induced arthritis by inhibiting osteoclast formation and function

Rheumatoid arthritis (RA) is a chronic inflammatory disease, characterized by severe joint inflammation and bone destruction as the result of increased numbers and activity of osteoclasts. RA is often associated with metabolic syndrome, whereby elevated levels of LDL are oxidized into oxLDL, which might affect osteoclastogenesis. In this study, we induced antigen-induced arthritis (AIA) in Apoe^-/- mice, which spontaneously develop high LDL levels, to investigate the effects of high LDL/oxLDL levels on osteoclast differentiation and bone destruction. Whereas basal levels of bone resorption were comparable between naive WT and Apoe^-/- mice, induction of AIA resulted in a significant reduction of bone destruction in Apoe^-/- mice as compared to WT controls. In line with that, the TRAP⁺ area on the cortical bone was significantly decreased. The absence of Apoe did affect neither the numbers of CD11b⁺Ly6C^high and CD11b^-/Ly6C^high osteoclast precursors (OCPs) in the BM of naïve mice nor their in vitro osteoclastogenic potential as indicated by comparable mRNA expression of osteoclast markers. Addition of oxLDL, but not LDL, to pre-osteoclasts from day 3 and mature osteoclasts from day 6 of osteoclastogenesis strongly reduced the number of TRAP⁺ osteoclasts and their resorptive capacity. This coincided with a decreased expression of various osteoclast markers. Interestingly, oxLDL significantly lowered the expression of osteoclast-associated receptor (Oscar) and the DNAX adaptor protein-12 encoding gene Tyrobp, which regulate the immunoreceptor tyrosine-based activation motif (ITAM) co-stimulation pathway that is strongly involved in osteoclastogenesis. Collectively, our findings suggest that under inflammatory conditions in the joint, high LDL levels lessen bone destruction during AIA, probably by formation of oxLDL that inhibits osteoclast formation and activity through modulation of the ITAM-signaling.

Impact of simultaneous neutralization of IL-17A and treatment with recombinant IL-2 on Th17-Treg cell population in S.aureus induced septic arthritis

The contribution of Th17 and Treg in the pathogenesis of septic arthritis is well known. The imbalance of Th17/Treg ratio, especially the skewed CD4⁺ T cell differentiation towards pathogenic Th17 lineage is a major reason that mediates bone damage through one of its prime cytokine member IL-17A. The neutralization of released IL-17A, as well as exogenous administration of IL-2 at a lower dose, was seen to be potent in dampening the inflammatory response in many cases. Interestingly the effect of IL-17A neutralization to limit IL-17 mediated inflammation and induction of Tregs by the administration of IL-2 has not been studied in experimental arthritis. So in this study, we have treated arthritic mice with IL-17A Ab and recombinant mouse IL-2 either alone or in combination at 3, 9 and 15 days post-infection. We have found a marked decrease in Th17 cell population and their related pro-inflammatory cytokine levels at 15DPI in arthritic mice after IL-17 neutralization. An increased Treg cell population was also observed in mice after application of rIL-2 with a significantly heightened TGF-β level in serum and synovial joints compared to the untreated one. However, in the case of combination therapy of IL-17A Ab and rIL-2 we have observed a beneficial effect in ameliorating the disease outcome as the arthritic index was decreased maximally at 15DPI with a significant reduction of arthritis compared to individual treatment. Overall the inflammatory microenvironment was counterbalanced most effectively in combination treatment by lowering the Th17/Treg ratio and their related cytokines that resulted in reducing the immunopathogenesis of the destructive arthritis.