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Aim: We aimed to evaluate the preventive role of the tyrosine kinase inhibitor dasatinib in an animal model of rheumatoid arthritis (RA). Methods: DBA/1J mice were injected with bovine type II collagen to induce arthritis (collagen‐induced arthritis [CIA]). There were four experimental groups of mice, namely negative control (non‐CIA), vehicle‐treated CIA, dasatinib‐pretreated CIA, and dasatinib‐treated CIA. After collagen immunization, arthritis progression in the mice was clinically scored twice weekly for 5 weeks. Flow cytometry was used to evaluate in vitro CD4+ T‐cell differentiation and ex vivo mast cell/CD4+ T‐cell differentiation. Osteoclast formation was evaluated using tartrate‐resistant acid phosphatase (TRAP) staining and by estimating the resorption pit area. Results: We found that the clinical arthritis histological scores were lower in the dasatinib pretreatment group than in the vehicle and dasatinib post‐treatment groups. Flow cytometry showed that FcεR1+ cells were downregulated and regulatory T cells were upregulated in splenocytes of the dasatinib pretreatment group compared with those in the vehicle group. Additionally, there was a decline in IL‐17+ CD4+ T‐cell differentiation and an increase in CD4+ CD24high Foxp3+ T‐cell differentiation with in vitro dasatinib treatment of human CD4+ T cells. The number of TRAP+ osteoclasts and the area of the resorption were decreased in the bone marrow cells derived from dasatinib‐pretreated mice compared with those derived from vehicle group. Conclusion: Dasatinib protected against arthritis in an animal model of RA by regulating the differentiation of regulatory T cells and IL‐17+ CD4+ T cells and inhibiting osteoclastogenesis, indicating the therapeutic potential of dasatinib in the treatment of early RA. [ABSTRACT FROM AUTHOR]

Clinical trials of biologic agents for chronic active antibody-mediated rejection (CAMR) in kidney transplant recipients (KTRs) have been disappointing. We performed a clinical trial of mesenchymal stem cell (MSC) treatment in KTRs with CAMR unresponsive to rituximab and intravenous immunoglobulin. This study was a phase 1 clinical trial to confirm patient safety. Two patients with CAMR unresponsive to rituximab and intravenous immunoglobulin were included. Each patient received allogeneic MSCs for 4 cycles (1 × 10 6 cells/kg every other week) via the peripheral vein in the distal arm. We observed adverse events and renal function for 6 months after the final MSC infusion and analyzed changes in immunomodulatory parameters in the peripheral blood between the start of treatment and 3 months after the final MSC infusion. There were no serious adverse events during the study period. Renal function was stable during MSC treatment but gradually decreased between the final MSC infusion and the study endpoint (patient 1: creatinine levels ranged from 3.01 mg/dL to 7.81 mg/dL, patient 2: 2.87 mg/dL to 3.91 mg/dL). In peripheral blood sample analysis between the start of treatment and 3 months after the final MSC infusion, there were similar trends for immunomodulatory markers. Our study showed that there were no serious adverse events for six months after allogeneic MSC treatment in KTRs with CAMR refractory to rituximab and intravenous immunoglobulin, but further studies need to define the efficacy of MSC treatment in CAMR. [ABSTRACT FROM AUTHOR]

Aim This study aimed to determine synovial fluid and serum biomarkers which could accord with radiological and ultrasonographic findings in knee osteoarthritis. Methods Thirty-four patients with knee osteoarthritis were detected with joint effusion by clinical examination. Both knee joints were examined using plain radiographs and ultrasonography. Questions were obtained for visual analog scale ( VAS), Western Ontario McMaster Universities Osteoarthritis Index and Health Assessment Questionnaire ( HAQ). Synovial fluid ( SF) and serum levels of vascular endothelial growth factor ( VEGF), matrix metalloproteinase ( MMP)-13, leptin, resistin and cartilage oligomeric matrix protein ( COMP) were measured using enzyme-linked immunosorbent assay. Results Synovial fluid VEGF level was positively correlated with Kellgren-Lawrence ( KL) grades and it was higher in patients with KL grade 4 than those with KL grade 2. SF VEGF correlated with ultrasonographic findings, such as the length of medial osteophytes. The amount of effusion was positively correlated with SF resistin. Serum leptin level had positive correlation with HAQ and the length of medial osteophytes. MMP-13 or COMP levels were not correlated with radiographic or ultrasonographic findings. Conclusion Synovial fluid VEGF level was correlated with radiographic grading, ultrasonographic findings and functional statues in knee osteoarthritis, and serum leptin level also correlated with the ultrasonographic findings and functional status of knee osteoarthritis. [ABSTRACT FROM AUTHOR]

Sirolimus ( SRL) is a promising alternative to calcineurin inhibitors, such as tacrolimus ( TAC), in kidney transplant recipients ( KTRs), but the immunological benefits of conversion from calcineurin inhibitors to SRL are not fully investigated. In the present study, we evaluated the effect of conversion from TAC to SRL on the T helper type 17/regulatory T (Th17/Treg) axis in three separate studies. First, the effect of SRL on the Th17/Treg axis was evaluated in vitro using peripheral blood mononuclear cells ( PBMCs). Second, the effect of conversion from TAC to SRL on the Th17/Treg axis was studied in KTRs. Finally, the effect of SRL on CD8+ Treg cells was evaluated. In vitro analysis of PBMCs isolated from KTRs showed that SRL suppressed Th17 cell differentiation but TAC did not. Conversion from TAC to SRL markedly decreased the number of effector memory CD8+ T cells and significantly increased the proportion of CD4+ and CD8+ Treg cells compared with TAC in KTRs. SRL treatment induced the CD8+ Treg cells, and these cells inhibited the proliferation of allogeneic CD4+ T cells and Th17 cells. In conclusion, conversion from TAC to SRL favourably regulates Th17 and Treg cell differentiation in KTRs. These findings provide a rationale for conversion from TAC to SRL in KTRs. [ABSTRACT FROM AUTHOR]

Objective Stromal cell-derived factor 1 (SDF-1) is a chemokine that is involved in the bone-destructive process in rheumatoid arthritis (RA) and bony metastasis in malignancy. This study was undertaken to determine the role and mechanism of SDF-1 in RA-associated osteoclastogenesis. Methods The expression of SDF-1, tumor necrosis factor α (TNFα), and RANKL in RA synovial tissue was analyzed using confocal microscopy. After synovial fibroblasts and CD4+ T cells were treated with SDF-1, RANKL messenger RNA expression was determined by real-time and reverse transcription polymerase chain reaction. Osteoclastogenesis was assessed by counting tartrate-resistant acid phosphatase-positive multinucleated cells in CD14+ monocytes cultured with SDF-1 in the presence of anticytokine antibodies or signal inhibitors and in monocytes cocultured with SDF-1-pretreated synovial fibroblasts and CD4+ T cells. Results RANKL, TNFα, and SDF-1 were coexpressed in the lining and sublining of RA synovium. SDF-1 stimulated RANKL expression in RA synovial fibroblasts and CD4+ T cells, and TNFα inhibition reduced this stimulation. When monocytes isolated from human peripheral blood were cultured with SDF-1, they were differentiated into osteoclasts in the absence of RANKL. Monocytes were also differentiated into osteoclasts when they were cocultured with SDF-1-pretreated synovial fibroblasts or CD4+T cells; however, this osteoclastogenesis was reduced by TNFα inhibition. Conclusion Our findings indicate that SDF-1 induces osteoclastogenesis directly and indirectly via up-regulating RANKL expression in RA synovial fibroblasts and CD4+ T cells, and that this is mediated by TNFα. The axis of SDF-1 and RANKL is a potential therapeutic target for RA-associated bone destruction. [ABSTRACT FROM AUTHOR]

Bone homeostasis, which involves formation and resorption, is an important process for maintaining adequate bone mass in humans. Rheumatoid arthritis (RA) is an autoimmune disease characterized by inflammation and bone loss, leading to joint destruction and deformity, and is a representative disease of disrupted bone homeostasis. The bone loss and joint destruction are mediated by immunological insults by proinflammatory cytokines and various immune cells. The connection between bone and immunity has been intensely studied and comprises the emerging field of osteoimmunology. Osteoimmunology is an interdisciplinary science investigating the interplay between the skeletal and the immune systems. The main contributors in osteoimmunology are the bone effector cells, such as osteoclasts or osteoblasts, and the immune cells, particularly lymphocytes and monocytes. Physiologically, osteoclasts originate from immune cells, and immune cells regulate osteoblasts and vice versa. Pathological conditions such as RA might affect these interactions, thereby altering bone homeostasis, resulting in the unfavorable outcome of bone destruction. In this review, we describe the osteoclastogenic roles of the proinflammatory cytokines and immune cells that are important in the pathophysiology of RA. [ABSTRACT FROM AUTHOR]

Objective: To examine the regulatory role of interleukin-22 (IL-22) in the expression of RANKL and induction of osteoclastogenesis in rheumatoid arthritis (RA)., Methods: Concentrations of IL-22 and RANKL in the serum and synovial fluid of RA patients were measured using enzyme-linked immunosorbent assay. RA synovial fibroblasts were treated with recombinant human IL-22 (rhIL-22), and the expression of RANKL messenger RNA (mRNA) and protein was measured using real-time polymerase chain reaction, Western blotting, and intracellular immunostaining. Human monocytes were cocultured with IL-22-prestimulated RA synovial fibroblasts and macrophage colony-stimulating factor, and osteoclastogenesis was assessed by counting the multinucleated cells (those staining positive for tartrate-resistant acid phosphatase)., Results: The IL-22 concentration in the synovial fluid was higher in RA patients than in patients with osteoarthritis (OA). The serum IL-22 concentration was also higher in RA patients than in OA patients and healthy volunteers, and this correlated with serum titers of rheumatoid factor and anti-cyclic citrullinated peptide antibodies. In RA synovial fibroblasts treated with rhIL-22, the expression of RANKL mRNA and protein was increased in a dose-dependent manner. IL-22-induced RANKL expression was down-regulated significantly by the inhibition of p38 MAPK/NF-κB or JAK-2/STAT-3 signaling. In human monocytes cocultured with IL-22-prestimulated RA synovial fibroblasts in the absence of exogenous RANKL, the monocytes differentiated into osteoclasts, but this osteoclastogenesis decreased after p38 MAPK/NF-κB or JAK-2/STAT-3 signaling was inhibited., Conclusion: These results show that IL-22 up-regulates RANKL expression in RA synovial fibroblasts and induces osteoclastogenesis. These effects are mediated by the p38 MAPK/NF-κB and JAK-2/STAT-3 signaling pathways., (Copyright © 2012 by the American College of Rheumatology.)

Objective: Stromal cell-derived factor 1 (SDF-1) is a potent chemoattractant for memory T cells in inflamed rheumatoid arthritis (RA) synovium. This study was undertaken to investigate the effect of interleukin-17 (IL-17) and CD40-CD40L interaction on SDF-1 production in RA fibroblast-like synoviocytes (FLS)., Methods: Synovial fluid (SF) and serum levels of SDF-1 in RA patients were measured by enzyme-linked immunosorbent assay (ELISA). The SDF-1 produced by cultured RA FLS was evaluated by real-time polymerase chain reaction and ELISA after FLS were treated with IL-17 and inhibitors of intracellular signal molecules. The SDF-1 level was also determined after FLS were cocultured with T cells in the presence and absence of IL-17., Results: Concentrations of SDF-1 in the sera and SF were higher in RA patients than in osteoarthritis patients, although the increase in the serum levels did not reach statistical significance. The production of SDF-1 in RA FLS was enhanced by IL-17 stimulation. This effect of IL-17 was blocked by inhibitors of phosphatidylinositol 3-kinase (PI 3-kinase), NF-kappaB, and activator protein 1 (AP-1). When FLS were cocultured with T cells, SDF-1 production was up-regulated, especially in the presence of IL-17, but FLS were inhibited by neutralizing anti-IL-17 and anti-CD40L antibodies. Addition of RA SF to cultured RA FLS significantly up-regulated SDF-1 messenger RNA expression, which was hampered by pretreatment with anti-IL-17 antibody., Conclusion: SDF-1 is overproduced in RA FLS, and IL-17 could up-regulate the expression of SDF-1 in RA FLS via pathways mediated by PI 3-kinase, NF-kappaB, and AP-1. Our findings suggest that inhibition of the interaction between IL-17 from T cells and SDF-1 in FLS may provide a new therapeutic approach in RA.