Effects of TNF Inhibitors on Parathyroid Hormone and Wnt Signaling Antagonists in Rheumatoid Arthritis

Effects of tofacitinib on bone turnover markers and bone modulators in patients with rheumatoid arthritis

BACKGROUND

Rheumatoid arthritis (RA) is characterized by bone loss. It is unclear whether JAK inhibitors can attenuate bone loss in RA by modulating bone metabolism. The main objective of our study is to investigate the effects of tofacitinib on serum levels of bone turnover markers and modulators. Secondary objectives were to assess changes in bone mineral density (BMD), metacarpal index, bone erosions.

METHODS

We conducted a prospective observational study on patients with active RA failure to bDMARDs or tsDMARDs initiating treatment with tofacitinib. We measured at baseline and after 1, 2, 3, 6, 9 and 12 months: serum bone turnover markers (CTX, P1nP, B-ALP), bone modulators (Dkk-1, sclerostin, vitamin D, PTH, OPG and RANKL), BMD and radiographic parameters (Sharp van der Heijde score [SvdH], bone health index [BHI] and metacarpal index [MCI]).

RESULTS

30 patients were enrolled in the study of whom 21 completed the study through month 12. Tofacitinib was clinically effective by suppressing DAS28-CRP. Glucocorticoids daily dose significantly decreased from baseline. We found a negative correlation between pre-study cumulative and daily dose of glucocorticoids and baseline B-ALP serum levels (r -0.592, p 0.012). Sclerostin serum levels increased significantly during the study period, while P1nP and B-ALP (markers of bone formation) decreased significantly. BMD levels, BHI, MCI and SvdH score did not change.

CONCLUSION

Treatment with tofacitinib was associated with a significant increase in sclerostin serum levels and a parallel decrease in markers of bone formation. However, no significant bone loss was observed.

Wnt/β-catenin signaling components and mechanisms in bone formation, homeostasis, and disease

Wnts are secreted, lipid-modified proteins that bind to different receptors on the cell surface to activate canonical or non-canonical Wnt signaling pathways, which control various biological processes throughout embryonic development and adult life. Aberrant Wnt signaling pathway underlies a wide range of human disease pathogeneses. In this review, we provide an update of Wnt/β-catenin signaling components and mechanisms in bone formation, homeostasis, and diseases. The Wnt proteins, receptors, activators, inhibitors, and the crosstalk of Wnt signaling pathways with other signaling pathways are summarized and discussed. We mainly review Wnt signaling functions in bone formation, homeostasis, and related diseases, and summarize mouse models carrying genetic modifications of Wnt signaling components. Moreover, the therapeutic strategies for treating bone diseases by targeting Wnt signaling, including the extracellular molecules, cytosol components, and nuclear components of Wnt signaling are reviewed. In summary, this paper reviews our current understanding of the mechanisms by which Wnt signaling regulates bone formation, homeostasis, and the efforts targeting Wnt signaling for treating bone diseases. Finally, the paper evaluates the important questions in Wnt signaling to be further explored based on the progress of new biological analytical technologies.

Plasma Sclerostin Levels in Rheumatoid Arthritis Women on TNF-α Inhibitor Therapy

Rheumatoid arthritis (RA) is associated with significant systemic and local bone loss. The aim of this study was to assess whether or not 15-month tumor necrosis factor α inhibitor (TNFαI) therapy in combination with methotrexate (MTX) affects circulating levels of sclerostin (SOST) in female RA patients. Plasma levels of SOST were measured using immunoassays kits. Baseline SOST levels showed no significant differences between RA patients and control participants. Postmenopausal women with RA tended to have higher sclerostin levels than premenopausal woman with RA. After 15 months of treatment with TNFαI, plasma levels of SOST were decreased. Before starting biological therapy, circulating levels of SOST significantly correlated with the patient's age (p < 0.05) and the marker of inflammation, such as ESR (p < 0.05). Multivariate regression analysis showed that age was the only significant predictor for baseline SOST levels in women with RA (β = 0.008, p = 0.028, R2 model = 0.293). Moreover, a positive correlation between SOST levels and the 28 joint disease activity score value based on the erythrocyte sedimentation rate (DAS28-ESR) was found at baseline (p < 0.05), as well as after 15 months of biological therapy (p < 0.05). Thus, plasma SOST levels may be helpful for monitoring the efficacy of TNFαI treatment in RA patients. According to our results, TNFαI, in combination with MTX, has a beneficial effect on bone turnover with a significant reduction in bone metabolism marker SOST.

Risk of fracture in women with glucocorticoid requiring diseases is independent from glucocorticoid use: An analysis on a nation-wide database

OBJECTIVE

Glucocorticoid-induced osteoporosis (GIOP) is a common cause of secondary osteoporosis. However, glucocorticoid requiring diseases pose a risk themselves for fracture. The aim of the present study was to determine the risk of fracture associated with variety of glucocorticoid requiring diseases independently from glucocorticoid use and other risk factors for osteoporosis.

METHODS

We conducted a retrospective cross-sectional analysis of a nation-wide cohort (DeFRACalc79 database). We used multivariable regression analysis adjusting for several risk factors for fracture and glucocorticoid intake to estimate the independent role of glucocorticoid requiring illnesses on fracture risk.

RESULTS

We found that patients with rheumatoid arthritis, connective tissue diseases, chronic obstructive pulmonary disease (COPD) and neurological diseases were at greater risk of vertebral or hip fracture (crude ORs 1.31, 1.20, 1.92 and 2.97 respectively). After adjusting for potential confounders COPD and neurological diseases remained significantly associated with an increased risk of vertebral or hip fractures (aORs 1.33, 95 % CI 1.18-1.49 and 2.43, 95 % CI 2.17-2.74). Rheumatoid arthritis, COPD, IBD and neurological diseases also significantly increased the risk of non-vertebral, non-hip fractures (aORs 1.23, 1.42, 1.52 and 1.94 respectively).

CONCLUSION

Some glucocorticoid requiring diseases were independently associated with an increased risk of fractures. COPD and neurological diseases with both vertebral and non-vertebral fracture risk while RA and IBD were independently associated only with non-vertebral, non-hip fractures.

The protective effects of Phoenixin-20 in tumor necrosis factor α (TNF-α)-induced cell senescence of rheumatoid arthritis fibroblast-like synoviocytes (FLS)

Rheumatoid arthritis (RA) is an age-related joint destruction disease that markedly impacts the normal life of patients. Currently, the clinical treatment strategies are far from satisfactory with severe side effects. Cellular senescence of fibroblast-like synoviocytes (FLS) has been reported to be involved in the pathological process of arthritis, which may provide an important research direction for RA treatment. Phoenixin-20 (PNX-20) is a peptide targeting G-protein-coupled receptor 173 (GPR173) with promising anti-inflammatory properties. Our study will probe into the function of PNX-20 on tumor necrosis factor α (TNF-α)- induced rheumatoid arthritis (RA) FLS cell senescence to provide a theoretical basis for treating RA with PNX-20. RA-FLSs were handled with 10 ng/mL TNF-α, followed by introducing Phoenixin-20 (10, 20 nM) or not for 7 days. Enhanced release of inflammatory cytokines, increased proportion of senescence-associated β-galactosidase (SA-β-gal) positive cells, and declined telomerase activity were all observed in TNF-α-treated RA-FLSs, accompanied by a noticeable decline in the p21 and p53 level, which were notably reversed by 10 and 20 nM PNX-20. Furthermore, the increased signal transducer and activator of transcription 6 (STAT6) level observed in TNF-α-treated RA-FLSs were signally repressed by PNX-20. Moreover, the impact of PNX-20 on TNF-α-induced cellular senescence in RA-FLSs was abrogated by the overexpression of STAT6. Collectively, PNX-20 protected the TNF-α-induced cell senescence in RA-FLSs by downregulating STAT6. Based on these findings, we speculate that PNX-20 might be a promising agent for the treatment of RA.

Changes in bone turnover markers and bone modulators during abatacept treatment

Rheumatoid arthritis (RA) causes bone loss, only partly related to inflammation. The impact of RA treatments on bone metabolism and their ability to mitigate bone loss remains uncertain. The primary goal of our study was to examine the influence of abatacept on serum levels of markers and regulators involved in bone turnover. Secondary objectives included evaluating changes in bone mineral density (BMD), bone health parameters, erosions, and exploring potential correlations among these parameters. We conducted a prospective observational study on patients with active seropositive RA failure to biological disease modifying anti-rheumatic drugs initiating treatment with abatacept. We measured at baseline and after 1, 2, 3, 6, 9 and 12 months: serum bone turnover markers (CTX, P1nP, B-ALP), bone modulators (Dkk-1, sclerostin, vitamin D, PTH, OPG and RANKL), BMD and radiographic parameters (modified Sharp van der Heijde score [mSvdH], bone health index [BHI] and metacarpal index [MCI]). Disease activity and glucocorticoid intake was monitored. 33 patients were enrolled in the study. We found a significant increase in markers of bone formation (B-ALP and P1nP) from baseline to M6 and M12. PTH increased significantly at M6 but not at M12. All other bone markers and modulators did not change. We found a significant decrease in BHI and MCI from baseline to M12 (median difference - 0.17 95% CI - 0.42 to - 0.10, p 0.001 and - 0.09 95% CI - 0.23 to - 0.07, respectively). BMD at femoral neck transitorily decreased at M6 (mean difference - 0.019 g/cm2 95% CI - 0.036 to - 0.001 p 0.04). BMD at total hip, lumbar spine and mSvdH score did not change significantly. P1nP delta at M12 correlated with delta mSvdH. Treatment with abatacept was associated with a significant increase in bone formation markers. The secondary and transient increase in PTH serum levels may be responsible of the transitory bone loss.

The plasma levels of Dickkopf-1 elevated in patients with Juvenile Idiopathic Arthritis

BACKGROUND

To explore the role of two major inhibitors of Wnt signal pathway, Dickkopf-1(DKK-1) and Sclerostin (SOST), in the pathogenesis of juvenile idiopathic arthritis (JIA).

METHODS

88 patients with JIA, which including 49 patients with enthesitis-related arthritis (ERA), 21 oligoarthritis (oJIA) and 18 polyarthritis (pJIA), and 36 age-and sex-matched children as healthy controls (HC) were enrolled in this study. The plasma levels of DKK-1 and SOST, measured using commercially available ELISA kits, were analyzed the correlation between the levels of DKK-1/SOST and JIA, and were analyzed in 14 patients with JIA during before and after treatment.

RESULTS

Plasma levels of DKK-1 were significantly higher in the patients with JIA than that in HC, the elevation of DKK-1 level was positively correlated with HLA-B27 positive JIA. DKK-1 levels dropped significantly in patient with JIA after treatment (P < 0.05). There was no significant change in SOST levels among different subtypes of JIA, patients with JIA during before and after treatment, and HC.

CONCLUSION

It was suggested that the DKK-1 may have a certain correlation with the pathogenesis of JIA, and DKK-1 levels are more closely related to the HLA-B27 positive-ERA.

IMPACT

The abnormally elevated levels of Dickkopf-1 (DKK-1) may be involved in the pathogenesis of juvenile idiopathic arthritis (JIA). DKK-1 levels were more closely related to the HLA-B27 positive-enthesitis-related arthritis (ERA). DKK-1 is an inhibitor of Wnt signaling pathway that promotes osteoblastic new bone formation; it is very rare for pediatric patients with HLA-B27 positive-ERA to manifest typical spondylitis, while sacroiliac arthritis is relatively common, which may be related to the high levels of DKK-1, which is consistent with the early stage of ankylosing spondylitis (AS).

Chronic arthritides and bone structure: focus on rheumatoid arthritis-an update

Normal bone remodeling depends of a balance between bone forming cells, osteoblasts and bone resorbing cells, the osteoclasts. In chronic arthritides and some inflammatory and autoimmune diseases such as rheumatoid arthritis, there is a great constellation of cytokines produced by pannus that impair bone formation and stimulate bone resorption by inducing osteoclast differentiation and inhibiting osteoblast maturation. Patients with chronic inflammation have multiple causes that lead to low bone mineral density, osteoporosis and a high risk of fracture including circulating cytokines, impaired mobility, chronic administration of glucocorticoids, low vitamin D levels and post-menopausal status in women, among others. Biologic agents and other therapeutic measures to reach prompt remission might ameliorate these deleterious effects. In many cases, bone acting agents need to be added to conventional treatment to reduce the risk of fractures and to preserve articular integrity and independency for daily living activities. A limited number of studies related to fractures in chronic arthritides were published, and future investigation is needed to determine the risk of fractures and the protective effects of different treatments to reduce this risk.

Secukinumab retention rate is greater in patients with psoriatic arthritis presenting with axial involvement

Psoriatic arthritis (PsA) is an inflammatory disease characterized by peripheral and axial involvement. Biological disease-modifying antirheumatic drugs (bDMARDs) are the mainstream treatment for PsA and bDMARDs retention rate is a proxy for the drug's overall effectiveness. However, it is unclear whether IL-17 inhibitors can have a higher retention rate than tumor necrosis factor (TNF) inhibitors, in particular in axial or peripheral PsA. A real-life observational study was conducted on bDMARD naïve PsA patients initiating TNF inhibitors or secukinumab. Time-to-switch analysis was carried out with Kaplan-Meyer curves (log-rank test) truncated at 3 years (1095 days). Sub-analyses of Kaplan-Meyer curves between patients presenting with prevalent peripheral PsA or prevalent axial PsA were also conducted. Cox regression models were employed to describe predictors of treatment switch/swap. Data on 269 patients with PsA naïve to bDMARD starting either TNF inhibitors (n=220) or secukinumab (n=48) were retrieved. The overall treatment retention at 1 and 2 years was similar for secukinumab and TNF inhibitors (log-rank test p NS). We found a trend towards significance in the Kaplan-Meyer at 3 years in favor of secukinumab (log-rank test p 0.081). Predominant axial disease was significantly associated with a higher chance of drug survival in secukinumab users (adjusted hazard ratio 0.15, 95% confidence interval = 0.04-0.54) but not in TNF inhibitor users. In this real-life, single-center, study on bDMARD naïve PsA patients, axial involvement was associated with longer survival of secukinumab but not of TNF inhibitors. Drug retention of secukinumab and TNF inhibitors were similar in predominantly peripheral PsA.

Oxidative Stress and Inflammation in Osteoporosis: Molecular Mechanisms Involved and the Relationship with microRNAs

Osteoporosis is characterized by the alteration of bone homeostasis due to an imbalance between osteoclastic bone resorption and osteoblastic bone formation. Estrogen deficiency causes bone loss and postmenopausal osteoporosis, the pathogenesis of which also involves oxidative stress, inflammatory processes, and the dysregulation of the expression of microRNAs (miRNAs) that control gene expression at post-transcriptional levels. Oxidative stress, due to an increase in reactive oxygen species (ROS), proinflammatory mediators and altered levels of miRNAs enhance osteoclastogenesis and reduce osteoblastogenesis through mechanisms involving the activation of MAPK and transcription factors. The present review summarizes the principal molecular mechanisms involved in the role of ROS and proinflammatory cytokines on osteoporosis. Moreover, it highlights the interplay among altered miRNA levels, oxidative stress, and an inflammatory state. In fact, ROS, by activating the transcriptional factors, can affect miRNA expression, and miRNAs can regulate ROS production and inflammatory processes. Therefore, the present review should help in identifying targets for the development of new therapeutic approaches to osteoporotic treatment and improve the quality of life of patients.

Effects of Biological/Targeted Therapies on Bone Mineral Density in Inflammatory Arthritis

Inflammatory arthritis has been reported to be associated with the development of osteoporosis. Recent research has investigated the mechanisms of bone metabolism in chronic inflammatory arthritis such as rheumatoid arthritis (RA) and spondyloarthritis (SpA). Progress in both animal and clinical studies has provided a better understanding of the osteoclastogenesis-related pathways regarding the receptor activator of nuclear factor-κB ligand (RANKL), anti-citrullinated protein antibodies (ACPAs), and Wnt signaling and Dickkopf-related protein 1 (Dkk-1). The complex interplay between inflammatory cytokines and bone destruction has been elucidated, especially that in the interleukin-17/23 (IL-17/23) axis and Janus kinase and signal transducer and activator of transcription (JAK-STAT) signaling. Moreover, advances in biological and targeted therapies have achieved essential modifications to the bone metabolism of these inflammatory arthritis types. In this narrative review, we discuss recent findings on the pathogenic effects on bone in RA and SpA. Proinflammatory cytokines, autoantibodies, and multiple signaling pathways play an essential role in bone destruction in RA and SpA patients. We also reviewed the underlying pathomechanisms of bone structure in biological and targeted therapies of RA and SpA. The clinical implications of tumor necrosis factor inhibitors, abatacept, rituximab, tocilizumab, Janus kinase inhibitors, and inhibitors of the IL-17/23 axis are discussed. Since these novel therapeutics provide new options for disease improvement and symptom control in patients with RA and SpA, further rigorous evidence is warranted to provide a clinical reference for physicians and patients.

Secondary Osteoporosis

Osteoporosis is a global public health problem, with fractures contributing to significant morbidity and mortality. Although postmenopausal osteoporosis is most common, up to 30% of postmenopausal women, > 50% of premenopausal women, and between 50% and 80% of men have secondary osteoporosis. Exclusion of secondary causes is important, as treatment of such patients often commences by treating the underlying condition. These are varied but often neglected, ranging from endocrine to chronic inflammatory and genetic conditions. General screening is recommended for all patients with osteoporosis, with advanced investigations reserved for premenopausal women and men aged < 50 years, for older patients in whom classical risk factors for osteoporosis are absent, and for all patients with the lowest bone mass (Z-score ≤ -2). The response of secondary osteoporosis to conventional anti-osteoporosis therapy may be inadequate if the underlying condition is unrecognized and untreated. Bone densitometry, using dual-energy x-ray absorptiometry, may underestimate fracture risk in some chronic diseases, including glucocorticoid-induced osteoporosis, type 2 diabetes, and obesity, and may overestimate fracture risk in others (eg, Turner syndrome). FRAX and trabecular bone score may provide additional information regarding fracture risk in secondary osteoporosis, but their use is limited to adults aged ≥ 40 years and ≥ 50 years, respectively. In addition, FRAX requires adjustment in some chronic conditions, such as glucocorticoid use, type 2 diabetes, and HIV. In most conditions, evidence for antiresorptive or anabolic therapy is limited to increases in bone mass. Current osteoporosis management guidelines also neglect secondary osteoporosis and these existing evidence gaps are discussed.

Regulation of bone mass in inflammatory diseases

Inflammation is among the major determinants of bone loss in chronic disease and aging. Bone metabolism is radically affected by inflammation with consequent bone loss and increased fracture risk. Various cytokines and mediators are involved in the pathogenesis of bone loss in inflammatory conditions. The present review has the aim of discussing the main pathways involved in the pathogenesis of bone loss in inflammatory diseases, focusing in particular on the Wnt system and its regulators. Literature review of studies published between inception to 2021 on osteoporosis and inflammation was conducted. I will discuss the epidemiology of osteoporosis and fractures in common inflammatory diseases. The molecular basis of bone loss related to inflammation will be discussed as well. Finally, the effects of various anti-inflammatory medications on bone metabolism will be reviewed.

Different Effects of Biologics on Systemic Bone Loss Protection in Rheumatoid Arthritis: An Interim Analysis of a Three-Year Longitudinal Cohort Study

Objective

To compare changes in bone mineral density (BMD) in rheumatoid arthritis (RA) patients receiving three-year conventional synthetic disease-modifying anti-rheumatic drugs (csDMARD), tumor necrosis factor-α inhibitors (TNFi), and abatacept.

Methods

Patients with RA were recruited from September 2014 to February 2021. Dual-energy X-ray absorptiometry was used to measure BMD at the femoral neck (FN), total hip (TH), and lumbar spine (L1-4) at enrollment and three years later. Changes in the BMD of each regimen group were analyzed. Multiple ordinary least squares regression was used with the dependent variables to develop a model to predict the change in BMD.

Results

A total of 752 participants were enrolled and 485 completed the three-year follow-up period. Of these, 375 (Group I), 84 (Group II), and 26 (Group III) participants received csDMARDs, TNFi, and abatacept therapy, respectively. Considering both type of therapy and completion of the follow-up period, participants were divided into groups A (csDMARDs, n = 104), B (TNFi, n = 52), and C (abatacept, n = 26). Compared to baseline, BMD decreased significantly at FN (p = 0.003) and L1-4 (p = 0.002) in Group A and at L1-4 (p = 0.005) in Group B, but remained stable at all sites in Group C. In terms of regression-adjusted percent change in BMD, there was a significant difference seen at all measured sites between group C compared to both groups A and B (+0.8%, -2.7%, -1.8% at FN; +0.5%, -1.1%, -1.0% at TH; +0.8%, -2.0%, -3.5% at L1-4, respectively; all p < 0.05). Anti-osteoporosis therapy had a BMD-preserving effect in RA.

Conclusion

Compared with csDMARDs and TNFi, abatacept may have a better BMD-preserving effect in RA. Anti-osteoporosis therapy can prevent systemic bone loss irrespective of RA therapy.

7-Hydroxycoumarin mitigates the severity of collagen-induced arthritis in rats by inhibiting proliferation and inducing apoptosis of fibroblast-like synoviocytes via suppression of Wnt/β-catenin signaling pathway

BACKGROUND

7-Hydroxycoumarin (7-HC) as a coumarin compound is widely found in Chinese herbs and exhibits diverse biological activities. Promoting cell apoptosis of fibroblast-like synoviocytes (FLS) is a meaningful strategy for rheumatoid arthritis (RA). Though the protective effect of 7-HC on RA experimental models has been reported, the specific mechanisms, especially the possible relationships of this effect to regulating FLS proliferation and apoptosis, still need clarification.

PURPOSE

This study clarified the therapeutic effects of 7-HC on collagen-induced arthritis (CIA) in rats and explored the underlying mechanisms.

METHODS

In vivo, 7-HC (15, 30 or 60 mg/kg) was intraperitoneally given to CIA rats, and its therapeutic effect and anti-inflammatory activity were evaluated. Ki67 immunohistochemistry, TUNEL assay and synovial proteins detection were conducted. In vitro, after treating with 7-HC (20, 40 or 80 μM) in TNF-α-stimulated RA FLS (MH7A cell line), cell proliferation and apoptosis were examined. The involvement of Wnt/β-catenin pathway was checked in vivo and in vitro.

RESULTS

7-HC attenuated the severity of rat CIA, evidenced by the reduction of paw swelling, arthritis index, joint damage, collagen type II antibody serum level, and IL-1β, IL-6, TNF-α production in serum and synovium. Particularly, 7-HC in vivo had anti-proliferative and pro-apoptotic effects on CIA rat synovial cells, indicated by reduced synovial Ki67 expression, raised synovial apoptosis index, decreased Bcl-2 protein level and increased level of Bax and cleaved caspase 3 protein. Further, 7-HC in vitro suppressed proliferation and promoted apoptosis of TNF-α-stimulated MH7A cells by regulating the mitochondrial pathway. Mechanistically, 7-HC treatment inhibited Wnt/β-catenin pathway, suggested by the reduction of pathway-related proteins (e.g. Wnt1, LRP6, p-GSK-3β (Ser9), β-catenin, cyclin D1 and c-Myc), the recovery of GSK-3β activity and the inhibition of β-catenin nuclear translocation. As expected, combined use of lithium chloride, an activator of Wnt/β-catenin signaling, reversed the anti-proliferative and pro-apoptotic effects of 7-HC in vitro.

CONCLUSION

7-HC relieved the severity of rat CIA by inhibiting cell proliferation and inducing apoptosis of rheumatoid FLS via inhibition of Wnt/β-catenin pathway.

Impact of Etanercept on Vitamin D Status and Vitamin D-binding Protein in Bio-naïve Patients with Psoriasis

High levels of serum vitamin D-binding protein have been shown previously in patients with psoriasis compared with healthy controls; a possible role in inflammation is implied. The primary objective of this study was to investigate the impact of 24-week etanercept treatment on vitamin D status and vitamin D-binding protein in patients with psoriasis. The secondary aim was to explore whether pre-treatment vitamin D levels could predict the treatment effect. A prospective observational study was performed, including 20 patients with psoriasis and 15 controls. Serum samples were analyzed for, among others, vitamin D metabolites, vitamin D-binding protein and highly sensitive Creactive protein. Baseline levels of vitamin D-binding protein were higher in patients with self-reported arthropathy than in those without. After 24 weeks’ treatment, an improvement in psoriasis was noted, as was a decrease in highly sensitive C-reactive protein. Vitamin D-binding protein decreased in those with self-reported arthropathy. Higher baseline levels of vitamin D were associated with faster and greater improvement in psoriasis. Vitamin D-binding protein may have an inflammatory biomarker role.

Etanercept prevents TNF-α mediated mandibular bone loss in FcγRIIb-/- lupus model

Patients with systemic lupus erythematosus are at increased risk for alveolar bone loss due to periodontitis possibly as a result of a pathogenic immune response to oral bacteria and inflammation. The aim of the present study was to investigate whether an anti-TNF-α antagonist could prevent mandibular bone loss in the FcγRIIb^-/- mouse model of lupus. Mice lacking FcγRIIb had decreased cancellous and cortical bone volume at 6 months of age. Etanercept increased cancellous but not cortical bone volume in WT and increased both cancellous bone volume and cortical thickness in FcγRIIb-deficient mice. FcγRIIb deficiency decreased mRNA levels for osteoblast marker genes, Osx, Col1a1 and Alp without any change in osteoclast marker genes. Etanercept increased Osx, Alp, and Ocn in both WT and FcγRIIb^-/- mice. Osteoclast marker genes including TNF-α, Trap and RANKL/OPG ratio was decreased in WT. Serum markers of proinflammatory cytokines, TNF-α, IFNγ, IL-6, and IL-17A, were increased in FcγRIIb^-/- mice and etanercept antagonized these effects in FcγRIIb^-/- mice. Etanercept increased serum PTH levels in the FcγRIIb^-/- mouse model of lupus. Our results suggest that deletion of FcγRIIb induces osteopenia by increasing the level of proinflammatory cytokines. Etanercept is effective in preventing mandibular bone loss in FcγRIIb^-/- mice, suggesting that anti-TNF-α therapy may be able to ameliorate mandibular bone loss in SLE patients with periodontitis.

Diffuse Idiopathic Skeletal Hyperostosis (DISH) in Type 2 Diabetes: A New Imaging Possibility and a New Biomarker

We performed a cross-sectional study to investigate the prevalence of Diffuse Idiopathic Skeletal Hyperostosis (DISH) through Dual-Energy X-ray absorptiometry (DXA) Vertebral Fracture Assessment (VFA) in a group of post-menopausal women with Type 2 Diabetes Mellitus (T2DM). We also explored several biomarkers of bone turnover metabolism, including Wnt pathway modulators. DXA-VFA was performed to detect the presence of DISH. Serum samples were collected from all patients at the time of study recruitment. 16 different serum biomarkers were tested between the two subgroups. Given the exploratory nature of the study, we did not adjust for multiplicity. At VFA analysis, among 96 individuals enrolled in the study 20 (20.8%) showed features of DISH. No statistically significant difference was found for BMD values, between the DISH and NO-DISH subgroups. Concerning blood biomarkers, DISH patients showed a significant difference only in the sclerostin serum levels (32 vs 35.5 pmol/L, for the DISH and NO-DISH subgroup, respectively; p = 0.010). After adjustment for confounding factors, sclerostin serum levels remained significantly lower in DISH group (p = 0.002). We demonstrated a non-negligible prevalence of DISH in a population of post-menopausal women affected by T2DM and suggested low serum sclerostin as a possible key feature associated with DISH presence. In addition, we propose DXA-VFA analysis, whose radiation dose is considerably lower than conventional radiography, as a viable diagnostic and prognostic mean to obtain data not only on bone health, but also for the screening for DISH in subjects at risk.

Osteoporosis in Inflammatory Arthritides: New Perspective on Pathogenesis and Treatment

Osteoporosis is a skeletal disorder characterized by impaired bone strength and increased risk of fragility fracture and is among the most relevant comorbidities of rheumatic diseases. The purpose of the present review is to discuss the pathogenesis of local and systemic bone involvement in inflammatory arthritides, especially Rheumatoid Arthritis, Psoriatic Arthritis, and Spondyloarthritides, as well as the effect of anti-rheumatic treatments and anti-osteoporotic medication on bone health and fracture incidence, including recent data on novel therapeutic perspective.

Roles of MicroRNAs in Bone Destruction of Rheumatoid Arthritis

As an important pathological result of rheumatoid arthritis (RA), bone destruction will lead to joint injury and dysfunction. The imbalance of bone metabolism caused by increased osteoclast activities and decreased osteoblast activities is the main cause of bone destruction in RA. MicroRNAs (MiRNAs) play an important role in regulating bone metabolic network. Recent studies have shown that miRNAs play indispensable roles in the occurrence and development of bone-related diseases including RA. In this paper, the role of miRNAs in regulating bone destruction of RA in recent years, especially the differentiation and activities of osteoclast and osteoblast, is reviewed. Our results will not only help provide ideas for further studies on miRNAs’ roles in regulating bone destruction, but give candidate targets for miRNAs-based drugs research in bone destruction therapy of RA as well.

Acute Effects of Glucocorticoid Treatment, TNFα or IL-6R Blockade on Bone Turnover Markers and Wnt Inhibitors in Early Rheumatoid Arthritis: A Pilot Study

Tumor Necrosis Factor (TNF)-α and Interleukin (IL)-6 play a fundamental role in bone loss in rheumatoid arthritis (RA), partly due to the inhibition of the Wnt canonical pathway. The aim of our study was to investigate the short-term effects of three different treatments on Wnt inhibitors (Dkk-1 and sclerostin) and on bone turnover markers (BTMs): N-propeptide of type I collagen (PINP) and C-terminal telopeptide of type I collagen (β-CTX-I). We performed a retrospective analysis of prospectively collected data. We enrolled women affected by early RA (< 12 months) with active disease (DAS28 ≥ 2.6) despite a 6-month treatment with methotrexate (10-15 mg/week), who then started certolizumab pegol, tocilizumab, or methyl-prednisolone (8 mg/daily). Patients were divided into three groups according to the treatment. Blood samples were collected at baseline, week 1, and week 4. We selected 14 patients treated with certolizumab pegol, 14 patients with tocilizumab, and 20 patients with methyl-prednisolone. No difference between any of the tested parameters was found at baseline. β-CTX-I, Dkk-1, and sclerostin decreased after 1 week of treatment with certolizumab pegol (- 27% ± 21.5, - 50% ± 13.2, and - 30% ± 30.4, respectively, p < 0.05). Methyl-prednisolone induced similar changes, albeit less marked, on β-CTX-I and Wnt inhibitors, with a decrease in PINP (- 16.1% ± 16.5, p < 0.05). Tocilizumab did not significantly affect BTMs or Wnt inhibitors. No significant changes were found for PTH and 25OHD. In the first four weeks of treatment, TNFα inhibition showed strong effects on BTMs and Wnt inhibitors, differently from IL-6 blockade. Glucocorticoids induced similar changes; nonetheless, they showed undesired effects on bone formation.

Osteoporosis in Rheumatic Diseases

Osteoporosis is a chronic disease characterized by an increased risk of fragility fracture. Patients affected by rheumatic diseases are at greater risk of developing osteoporosis. The purpose of the present review is to discuss the pathogenesis, epidemiology, and treatment of osteoporosis in patients affected by rheumatic diseases with special focus for rheumatoid arthritis, psoriatic arthritis, spondyloarthritis, systemic lupus erythematosus, systemic sclerosis, vasculitides, Sjogren syndrome, and crystal-induced arthritis.

Wnt Signaling and Biological Therapy in Rheumatoid Arthritis and Spondyloarthritis

The Wnt signaling pathway plays a key role in several biological processes, such as cellular proliferation and tissue regeneration, and its dysregulation is involved in the pathogenesis of many autoimmune diseases. Several evidences support its role especially in bone complications of rheumatic diseases. In Rheumatoid Arthritis (RA), the Wnt signaling is implicated in systemic and localized bone loss, while available data of its role in Spondyloarthritis (SpA) are conflicting. In the last few decades, the quality of life of rheumatic patients has been dramatically improved by biological therapy, targeting cytokines involved in the pathogenesis of these diseases like tumor necrosis factor (TNF)α, interleukin (IL)-1, IL-6, IL-17. In this review, we reviewed the role of Wnt signaling in RA and SpA, focusing on the effect of biological therapy on this pathway and its possible clinical implications.

Acetyl-11-keto-β-boswellic acid attenuates titanium particle-induced osteogenic inhibition via activation of the GSK-3β/β-catenin signaling pathway

Rationale: Peri-prosthetic osteolysis (PPO) is mainly induced by wear particles and represents the leading cause of implant failure and revision surgery. Previous studies have identified mitigation of wear particle-induced inflammation and bone resorption as the main approaches to treat PPO. Recently, wear particle-induced reduction of bone formation around the prosthesis was identified as a major factor in the development of PPO. Acetyl-11-keto-β-boswellic acid (AKBA), a derivative of frankincense, has been shown to play a potential role in bone metabolism. However, whether AKBA enhances bone formation in wear particle-induced osteolysis remains unknown. In this study, we examined whether AKBA attenuates titanium particle-induced osteogenic reduction.

Methods: Titanium particles were used to induce osteolysis in murine calvaria, and micro-CT and histological analyses were used to evaluate the results. Mouse osteoblast cells, MC3T3-E1 were co-cultured with titanium particles to determine their effect on osteoblast formation in vitro.

Results: We demonstrated that AKBA treatment significantly inhibited titanium particle-induced osteogenic inhibition by enhancing osteogenesis both in vivo and in vitro. AKBA treatment also enhanced the phosphorylation of GSK-3β, decreased the degradation of β-catenin, and increased the translocation of β-catenin from the cytoplasm to the nucleus. Taken together, these results showed that AKBA treatment attenuated titanium-induced osteogenic inhibition by activating the GSK-3β/β-catenin signaling pathway.

Conclusion: These findings suggest that AKBA is a promising new target in the prevention and treatment of PPO.

Updates in CKD-Associated Osteoporosis

PURPOSE OF REVIEW

Chronic kidney disease (CKD) is associated with bone loss and fractures. The purpose of this review is to provide clinicians with an overview of the underlying pathogenesis of CKD-associated osteoporosis, and a summary of the current diagnostic and therapeutic approaches to this disease.

RECENT FINDINGS

In 2017, the Kidney Disease Improving Global Outcomes Committee on Bone Quality updated their guidelines to include screening for osteoporosis and fracture risk by dual energy X-ray absorptiometry in patients with CKD. Once a diagnosis of osteoporosis and/or fracture risk is established, it is not clear how nephrologists should manage their patients. Patients with CKD should be screened for CKD-associated osteoporosis and considered for strategies that prevent bone loss and fractures. Assessment of bone turnover via imaging, biochemical testing, or bone biopsy can help guide the choice of therapy. Randomized controlled trials are needed to assess safety and efficacy of treatments to prevent bone loss and fractures.

Celastrol inhibits glucocorticoid‑induced osteoporosis in rat via the PI3K/AKT and Wnt signaling pathways

Modern pharmacological studies revealed that Celastrol exhibits anti‑inflammation, anti‑bacteria, anti‑virus, anti‑fertility, insect‑resistance functions and has been used for the treatment of rheumatism, rheumatoid arthritis, blood diseases, skin diseases and agricultural insecticide. The present study aimed to investigate the effects of Celastrol on glucocorticoid‑induced osteoporosis (GIOP) and the underlying molecular mechanisms. The findings of the current study revealed that Celastrol reduced body weight, urine calcium/creatinine, tartrate‑resistant acid phosphatase 5b, C‑terminal telopeptide of type I collagen, and induced osteocalcin in GIOP rats. In addition, alkaline phosphatase, triiodothyronine receptor auxiliary protein and cathepsin K mRNA expression levels were effectively suppressed, and osteocalcin, bone morphogenetic protein 2, type I collagen and runt‑related transcription factor 2 mRNA expression levels were effectively induced in osteoporosis rats treated with Celastrol. Celastrol inhibited prostaglandin E2 and caspase‑3 protein expression levels, and induced phosphoinositol 3‑kinase (PI3K), phosphorylated‑protein kinase B (AKT) and glycogen synthase kinase‑3 phosphorylation, Wnt and β‑catenin protein expression in GIOP rats. The present study demonstrated that Celastrol may inhibit GIOP in rats via the PI3K/AKT and Wnt signaling pathways.

Rheumatoid arthritis in remission : Decreased myostatin and increased serum levels of periostin

Background

Chronic inflammation of rheumatoid arthritis (RA) is associated with disturbances in muscle and bone metabolism.

Aim

The purpose of this study was to investigate whether endocrine regulators of myogenesis and bone metabolism in patients with rheumatoid arthritis (RA) in remission differed from unaffected healthy controls. An additional point was whether these were associated with patients’ health-related functioning or particular bodily functions of the International Classification of Functioning, Disability and Health (ICF).

Methods

Bone turnover and the markers for muscle, i.e. myostatin (MSTN), follistatin (FSTN), growth differentiation factor (GDF-15) and for bone, i.e. sclerostin (SOST), dickkopf 1 (Dkk1), periostin (PSTN) metabolism were determined in 24 female RA patients and matched healthy controls. The chair rising test (CRT), timed up and go test (TUG), 6 min walking test, maximum hand grip and back extensor strength tests were used to assess patients’ health-related functions. Additionally, bone mineral density of the lumbar spine and the hip region was measured.

Results

For the bone turnover markers no differences were observed between patients and controls. In contrast, the markers MSTN and Dkk1 were significantly lower and FSTN and PSTN significantly higher in patients than controls. Patients performed worse in the CRT and TUG. Some correlations reflected associations between these endocrine factors and physical function.

Conclusion

Anti-inflammatory therapy may be responsible for the positive effect on endocrine factors influencing myogenesis. Elevation of PSTN probably reflects the increased risk of fragility fractures in RA patients.

Effects of denosumab on bone metabolism and bone mineral density with anti-TNF inhibitors, tocilizumab, or abatacept in osteoporosis with rheumatoid arthritis

Introduction

The aim of this 18-month retrospective study was to evaluate the differences in outcomes of denosumab with tumor necrosis factor (TNF) inhibitors (TNFis), tocilizumab (TCZ), or abatacept (ABT) treatment in osteoporosis (OP) patients with rheumatoid arthritis (RA).

Patients and methods

Patients were divided into TNFis-treated (TNF group; 44 cases), TCZ-treated (TCZ group; 8 cases), or ABT-treated (ABT group; 14 cases) groups. We measured serum bone-specific alkaline phosphatase (BAP) and tartrate-resistant acid phosphatase 5b (TRACP-5b) at baseline and every 3 months for 18 months and assessed bone mineral density (BMD) of the lumbar 1–4 vertebrae (L-BMD) and total hip BMD (H-BMD) at baseline and every 6 months for 18 months.

Results

There were no significant differences in the percent changes in BAP, TRACP-5b, or L-BMD among the groups. The percent change in H-BMD was significantly increased in the TCZ group at 12 months or at 12 and 18 months, compared with that in the ABT group or TNF group, respectively. The percent change in L-BMD was significantly increased at 12 months in the TCZ and TNF groups, and at 18 months in all the 3 groups compared with pretreatment levels, whereas the percent change in H-BMD was significantly higher at 6, 12, and 18 months in the TCZ group, at 12 and 18 months in the TNF group, and at 18 months in the ABT group, compared with pretreatment levels.

Conclusion

Our findings suggest that TCZ might be more useful than TNF or ABT in light of the observed H-BMD increases with denosumab therapy for OP patients with RA.

TXNDC5 synergizes with HSC70 to exacerbate the inflammatory phenotype of synovial fibroblasts in rheumatoid arthritis through NF-κB signaling

The upregulated expression of thioredoxin domain-containing protein 5 (TXNDC5) is associated with rheumatoid arthritis in patients and model mice. However, the underlying mechanism by which TXNDC5 influences the pathological activation of rheumatoid arthritis synovial fibroblasts (RASFs) remains unknown. In this study, we show that TXNDC5 expression in RASFs and their cytokine production are significantly upregulated in response to LPS, TNF-α and IL-6, but suppressed by transfection with TXNDC5-siRNA. TXNDC5 is further validated as the direct target of NF-κB signaling. Mechanistically, TXNDC5 directly interacts with heat shock cognate 70 protein (HSC70) to sequester it in the cytoplasm, and HSC70 silencing exerts the same effects as TXNDC5 on the biological activity of RASFs (for example, decreased cell viability, invasion and cytokine production). Furthermore, HSC70 activates NF-κB signaling by destabilizing IκBβ protein in the absence of LPS or facilitating its nuclear translocation in the presence of LPS. Importantly, TXNDC5 can also regulate the activity of NF-κB signaling in a HSC70-IκBβ-dependent manner. Taken together, by linking HSC70 and NF-κB signaling, TXNDC5 plays a pro-inflammatory role in RASFs, highlighting a potential approach to treat RA by blocking the TXNDC5/HSC70 interaction.

Circulating Biomarkers for Predicting Infliximab Response in Rheumatoid Arthritis: A Systematic Bioinformatics Analysis

Background

Infliximab shows good efficacy in treating refractory rheumatoid arthritis (RA). However, many patients responded poorly and related studies were inconsistent in predictive biomarkers. This study aimed to identify circulating biomarkers for predicting infliximab response in RA.

Material/Methods

Public databases of Gene Expression Omnibus (GEO) and ArrayExpress were searched for related microarray datasets, focused on the response to infliximab in RA. All peripheral blood samples were collected before infliximab treatment and gene expression profiles were measured using microarray. Differential genes associated with infliximab efficacy were analyzed. The genes recognized by half of the datasets were regarded as candidate biomarkers and validated by prospective datasets.

Results

Eight microarray datasets were identified with 374 blood samples of RA patients, among which 191 (51.1%) were diagnosed as non-responders in the subsequent infliximab treatment. Five genes (FKBP1A, FGF12, ANO1, LRRC31, and AKR1D1) were associated with the efficacy and recognized by half of the datasets. The 5-gene model showed a good predictive power in random- and prospective-designed studies, with AUC (area under receiver operating characteristic [ROC] curve)=0.963 and 1.000, and it was also applicable at the early phase of treatment (at week 2) for predicting the response at week 14 (AUC=1.000). In the placebo group, the model failed to predict the response (AUC=0.697), indicating the model’s specificity in infliximab treatment.

Conclusions

The model of FKBP1A, FGF12, ANO1, LRRC31, and AKR1D1 in peripheral blood is useful for efficiently predicting the response to infliximab treatment in rheumatoid arthritis.

Denosumab: targeting the RANKL pathway to treat rheumatoid arthritis

INTRODUCTION

Rheumatoid arthritis (RA) is a chronic inflammatory disorder characterized by focal pathologic bone resorption due to excessive activity of osteoclasts (OC). Receptor activator of nuclear factor kappa B ligand (RANKL) is essential for the proliferation, differentiation, and survival of OC. Denosumab (DMab) is a humanized monoclonal antibody that binds to RANKL with high affinity and blocks its subsequent association with its receptor RANK on the surface of OC precursors. Area covered: The authors review the molecular and cellular mechanisms underlying therapeutic applications of DMab, provide recent highlights on pharmacology, efficacy and safety of DMab, and discuss the potential of DMab as a novel therapeutic option for the treatment of rheumatoid arthritis. Expert opinion: Clinical results suggest that DMab is efficient both in systemic and articular bone loss in RA with limited side effects. Diminished bone erosion activity was also noted in RA patients on corticosteroids and bisphosphonates. Combination of DMab with an anti-TNF agent was not associated with increased infection rates. Collectively, these data indicate that DMab, in combination with methotrexate and possibly other conventional synthetic Disease Modifying Anti-Rheumatic Drugs (csDMARDs), is an effective, safe and cost-effective option for the treatment of RA.

Reconstruction and analysis of the lncRNA–miRNA–mRNA network based on competitive endogenous RNA reveal functional lncRNAs in rheumatoid arthritis

Rheumatoid arthritis (RA) is an autoimmune disease with an unknown etiology, occurring in approximately 1.0% of general population.

Effect of Osteoprotegerin and Dickkopf-Related Protein 1 on Radiological Progression in Tightly Controlled Rheumatoid Arthritis

Objective

To analyze the association between circulating osteoprotegerin (OPG) and Dickkopf-related protein 1 (DKK-1) and radiological progression in patients with tightly controlled rheumatoid arthritis (RA).

Methods

Serum levels of OPG and DKK-1 were measured in 97 RA patients who were treated according to a treat-to-target strategy (T2T) aimed at remission (DAS28<2.6). Radiologic joint damage progression was assessed by changes in the total Sharp-van der Heijde score (SHS) on serial radiographs of the hands and feet. The independent association between these biomarker levels and the structural damage endpoint was examined using regression analysis

Results

The mean age of the 97 RA patients (68 women) at the time of the study was 54 ± 14 years, and the median disease duration was 1.6 ± 1.5 years. Most patients were seropositive for either RF or ACPA, and the large majority (76%) were in remission or had low disease activity.

After a median follow-up time of 3.3 ± 1.5 years (range, 1–7.5 yrs.), the mean total SHS annual progression was 0.88 ± 2.20 units. Fifty-two percent of the patients had no progression (defined as a total SHS of zero). The mean serum OPG level did not change significantly over the study period (from 3.9 ± 1.8 to 4.07 ± 2.23 pmol/L), whereas the mean serum DKK-1 level decreased, although not significantly (from 29.9 ± 10.9 to 23.6 ± 18.8 pmol/L).

In the multivariate analysis, the predictive factors increasing the likelihood of total SHS progression were age (OR per year = 1.10; p = 0.003) and a high mean C-reactive protein level over the study period (OR = 1.29; p = 0.005). Circulating OPG showed a protective effect reducing the likelihood of joint space narrowing by 60% (95% CI: 0.38–0.94) and the total SHS progression by 48% (95% CI: 0.28–0.83). The DKK-1 levels were not associated with radiological progression.

Conclusion

In patients with tightly controlled RA, serum OPG was inversely associated with progression of joint destruction. This biomarker may be useful in combination with other risk factors to improve prediction in patients in clinical remission or low disease activity state.