Soluble Siglec-9 suppresses arthritis in a collagen-induced arthritis mouse model and inhibits M1 activation of RAW264.7 macrophages

Background

The aim of this study was to assess the effects of soluble sialic acid-binding immunoglobulin-type lectin (sSiglec)-9 on joint inflammation and destruction in a murine collagen-induced arthritis (CIA) model and in monolayer cultures of murine macrophages (RAW264.7 cells and peritoneal macrophages) and fibroblast-like synoviocytes (FLS) derived from patients with rheumatoid arthritis.

Methods

DBA/1J mice were immunized with type II collagen. Effects of sSiglec-9 were evaluated using a physiologic arthritis score, histological analysis, serum tumor necrosis factor (TNF)-α concentration, and the proportion of forkhead box P3 (Foxp3)-positive regulatory T (Treg) cells. In vivo biofluorescence imaging was used to assess the distribution of sSiglec-9. Levels of M1 (TNF-α, interleukin [IL]-6, and inducible nitric oxide synthase) and M2 (CD206, Arginase-1, and IL-10) macrophage markers and phosphorylation of intracellular signaling molecules were examined in macrophages, and levels of matrix metalloproteinase (MMP)-1, MMP-3, and MMP-13 were examined in FLS.

Results

sSiglec-9 significantly suppressed the clinical and histological incidence and severity of arthritis. The proportion of Foxp3-positive Treg cells significantly improved and serum TNF-α concentration decreased in vivo. Although sSiglec-9 reduced the expression of M1 markers in macrophages, it did not affect the expression of M2 markers and MMPs in FLS. Nuclear factor (NF)-kB p65 phosphorylation was attenuated by sSiglec-9, and chemical blockade of the NF-kB pathway reduced M1 marker expression in RAW264.7 cells.

Conclusions

In this study, we have demonstrated the therapeutic effects of sSiglec-9 in a murine CIA model. The mechanism underlying these effects involves the suppression of M1 proinflammatory macrophages by inhibiting the NF-kB pathway. sSiglec-9 may provide a novel therapeutic option for patients with rheumatoid arthritis refractory to currently available drugs.

Factors secreted from dental pulp stem cells show multifaceted benefits for treating experimental rheumatoid arthritis

Rheumatoid arthritis (RA) is an autoimmune disease characterized by synovial hyperplasia and chronic inflammation, which lead to the progressive destruction of cartilage and bone in the joints. Numerous studies have reported that administrations of various types of MSCs improve arthritis symptoms in animal models, by paracrine mechanisms. However, the therapeutic effects of the secreted factors alone, without the cell graft, have been uncertain. Here, we show that a single intravenous administration of serum-free conditioned medium (CM) from human deciduous dental pulp stem cells (SHED-CM) into anti-collagen type II antibody-induced arthritis (CAIA), a mouse model of rheumatoid arthritis (RA), markedly improved the arthritis symptoms and joint destruction. The therapeutic efficacy of SHED-CM was associated with an induction of anti-inflammatory M2 macrophages in the CAIA joints and the abrogation of RANKL expression. SHED-CM specifically depleted of an M2 macrophage inducer, the secreted ectodomain of sialic acid-binding Ig-like lectin-9 (ED-Siglec-9), exhibited a reduced ability to induce M2-related gene expression and attenuate CAIA. SHED-CM also inhibited the RANKL-induced osteoclastogenesis in vitro. Collectively, our findings suggest that SHED-CM provides multifaceted therapeutic effects for treating CAIA, including the ED-Siglec-9-dependent induction of M2 macrophage polarization and inhibition of osteoclastogenesis. Thus, SHED-CM may represent a novel anti-inflammatory and reparative therapy for RA.

Effects of Concomitant Methotrexate on Large Joint Replacement in Patients With Rheumatoid Arthritis Treated With Tumor Necrosis Factor Inhibitors: A Multicenter Retrospective Cohort Study in Japan

OBJECTIVE

To determine the effects of concomitant methotrexate (MTX) on the incidence of large joint replacement resulting from the progression of large joint destruction in patients with rheumatoid arthritis (RA) treated with tumor necrosis factor (TNF) inhibitors.

METHODS

A retrospective cohort study was performed using a multicenter registry. In total, 803 patients with RA who received etanercept or adalimumab were included. The first large joint replacement during treatment with etanercept or adalimumab was used as the outcome variable in predictive analyses. The cumulative incidence of large joint replacement was estimated using Kaplan-Meier curves, and the impact of concomitant MTX on the incidence of large joint replacement was assessed with Cox proportional hazards models. Propensity score matching was used to reduce selection bias.

RESULTS

Of all patients, 601 (75%) received concomitant MTX at a median dosage of 8 mg/week (interquartile range 6-8). A total of 49 patients (62 joints) underwent large joint replacement during treatment with etanercept or adalimumab. The incidence of large joint replacement for patients with concomitant MTX was significantly lower than that for patients without MTX (P < 0.001). Multivariate analysis revealed that concomitant MTX independently predicted large joint replacement (hazard ratio 0.36, 95% confidence interval 0.20-0.65). Additionally, propensity score-matched analysis demonstrated that patients with concomitant MTX had a significantly lower incidence of large joint replacement than those without concomitant MTX (P = 0.032).

CONCLUSION

Concomitant MTX reduces the incidence of large joint replacement in patients with RA treated with TNF inhibitors.

Predictive factors for achieving low disease activity at 52 weeks after switching from tumor necrosis factor inhibitors to abatacept: results from a multicenter observational cohort study of Japanese patients

This study aimed to identify predictive factors for achieving low disease activity (LDA) in rheumatoid arthritis (RA) patients switching from tumor necrosis factor inhibitors (TNFis) to abatacept (ABT). Patients who were registered in the multicenter observational Tsurumai Biologics Communication Registry (TBCR) were enrolled in this study. Predictive factors for LDA achievement at each time point were determined by univariate and multivariate logistic regression analyses. The cutoffs of 28-point count Disease Activity Score (DAS28)-C-reactive protein (CRP) and ΔDAS28-CRP from baseline up to 24 weeks for LDA achievement at 52 weeks were explored using receiver operating characteristic (ROC) curves. Of 2771 RA patients registered until 2013, 76 with moderate or high disease activity were selected. Twenty-six percent of the patients achieved LDA. Multivariate analysis confirmed that DAS28-CRP at 12 weeks and ΔDAS28-CRP from baseline to 12 weeks were independent factors for LDA achievement at 52 weeks [odds ratio (OR) 0.26, 95% confident interval (CI) (0.12-0.56), OR 0.25, 95% CI (0.11-0.57), respectively]. The best cutoff values of DAS28-CRP at 12 weeks and ΔDAS28-CRP from baseline to 12 weeks for LDA at 52 weeks were 3.9 (sensitivity 0.85, specificity 0.78) and -0.97 (sensitivity 0.70, specificity 0.70), respectively. Seventy-one percent of patients who achieved both of these cutoff values at 12 weeks achieved LDA at 52 weeks. Our findings suggest that the clinical course up to 12 weeks is important for predicting long-term outcomes when switching from TNFis to ABT.

Concomitant Methotrexate Protects Against Total Knee Arthroplasty in Patients with Rheumatoid Arthritis Treated with Tumor Necrosis Factor Inhibitors

OBJECTIVE

To determine the effects of concomitant methotrexate (MTX) on the incidence of total knee arthroplasty (TKA) resulting from the progression of joint destruction in patients with rheumatoid arthritis (RA) during longterm treatment with tumor necrosis factor (TNF) inhibitors.

METHODS

A total of 155 patients with RA (310 knee joints) received TNF inhibitors at our institute between May 1, 2001, and May 31, 2008. A total of 111 symptomatic (tender and/or swollen) knee joints in 68 patients were retrospectively studied over the course of a minimum of 5 years of followup. The median (interquartile range) followup period was 8.1 (7.0-9.3) years. All data were analyzed using the knee joint as the statistical unit of analysis. TKA during treatment with TNF inhibitors was used as the outcome variable in predictive analyses. The cumulative incidence of TKA was compared by concomitant or no MTX use (MTX±).

RESULTS

There were 79 subjects (71%) who received concomitant MTX. According to Kaplan-Meier estimates, the cumulative incidence of TKA for the MTX+ group was significantly lower than that for the MTX- group (24% vs 45% at 5 yrs, respectively, p = 0.035). Multivariate analysis using the Cox proportional hazards model revealed that concomitant MTX (HR 0.44, 95% CI 0.22-0.89), Larsen grade (HR 2.93, 95% CI 1.94-4.41), and older age at baseline (HR 1.04, 95% CI 1.01-1.08) were independent predictors of TKA.

CONCLUSION

Concomitant MTX reduces the incidence of TKA by 56% in patients with RA during longterm treatment with TNF inhibitors.

Disease activity early in treatment as a predictor of future low disease activity in RA patients treated with iguratimod

OBJECTIVES

This retrospective observational study aimed to examine the efficacy of iguratimod with and without concomitant methotrexate (MTX) and to estimate the adequate observational period for predicting low disease activity (LDA) achievement at 24 weeks in patients with rheumatoid arthritis (RA).

METHODS

All patients treated with iguratimod were registered in a Japanese multicenter registry. Multivariate analyses were performed to identify predictive factors for LDA achievement at 24 weeks. Receiver operating characteristic (ROC) curve analyses were performed to estimate the association of 28-joint disease activity score based on erythrocyte sedimentation rate (DAS28-ESR) at each time point with achievement of LDA at 24 weeks and determine a cut-off for DAS28-ESR.

RESULTS

A total of 123 patients were treated with iguratimod with (n = 65) or without (n = 58) MTX. Iguratimod therapy resulted in significant clinical improvement in both groups. Multivariate analysis revealed that DAS28-ESR at each time point was an independent significant predictor of LDA achievement at 24 weeks. Cut-off values of DAS28-ESR at 12 weeks based on ROC curves were 3.2 and 3.6 in patients with and without MTX, respectively.

CONCLUSIONS

Iguratimod was effective in RA patients in clinical practice. Our results suggest that 12 weeks may be a sufficient period to judge the medium-term efficacy of iguratimod in patients treated with and without MTX.

A short-wavelength infrared emitting multimodal probe for non-invasive visualization of phagocyte cell migration in living mice

For the non-invasive visualization of cell migration in deep tissues, we synthesized a short-wavelength infrared (SWIR) emitting multimodal probe that contains PbS/CdS quantum dots, rhodamine 6G and iron oxide nanoparticles. This probe enables multimodal (SWIR fluorescence/magnetic resonance) imaging of phagocyte cell migration in living mice.

Comparison of the prognosis of bisphosphonate-related osteonecrosis of the jaw caused by oral and intravenous bisphosphonates

Bisphosphonates (BPs) have been used in medical practice for the treatment of osteoporosis, bone metastasis, and multiple myeloma. Although many studies have been published, the treatment and prognosis of bisphosphonate-related osteonecrosis of the jaw (BRONJ) remain unclear. This study included 59 patients with BRONJ: 29 had taken oral BPs and 30 had taken intravenous (IV) BPs. All received conservative treatments. When separated sequestra were seen, a sequestrectomy was performed. Segmental mandibular resection was performed when pathological fractures were diagnosed. The outcomes of treatments were compared between groups. For patients treated with oral rinses or mandibular resection, the number in whom clinical healing was observed did not differ between the oral BP and IV BP groups. With regard to sequestrectomy, 94% of patients in the oral BP group showed improvement with this treatment compared to 50% in the IV BP group. The number of patients in whom clinical healing of BRONJ was achieved was statistically better in the oral BP group than in the IV BP group after 6 months of treatment (P<0.001). The results showed that >90% of patients treated with oral BPs could be cured. However, 50% of patients treated with IV BPs did not show an improvement. Additional research is needed to further increase the therapeutic efficacy for the resolution of BRONJ.