Myeloid-derived suppressor cells play crucial roles in the regulation of mouse collagen-induced arthritis.

Myeloid-derived suppressor cells (MDSCs) are of myeloid origin and are able to suppress T cell responses. The role of MDSCs in autoimmune diseases remains controversial, and little is known about the function of MDSCs in autoimmune arthritis. In this study, we clarify that MDSCs play crucial roles in the regulation of proinflammatory immune response in a collagen-induced arthritis (CIA) mouse model. MDSCs accumulated in the spleens of mice with CIA when arthritis severity peaked. These MDSCs inhibited the proliferation of CD4(+) T cells and their differentiation into Th17 cells in vitro. Moreover, MDSCs inhibited the production of IFN-γ, IL-2, TNF-α, and IL-6 by CD4(+) T cells in vitro, whereas they promoted the production of IL-10. Adoptive transfer of MDSCs reduced the severity of CIA in vivo, which was accompanied by a decrease in the number of CD4(+) T cells and Th17 cells in the draining lymph nodes. However, depletion of MDSCs abrogated the spontaneous improvement of CIA. In conclusion, MDSCs in CIA suppress the progression of CIA by inhibiting the proinflammatory immune response of CD4(+) T cells. These observations suggest that MDSCs play crucial roles in the regulation of autoimmune arthritis, which could be exploited in new cell-based therapies for human rheumatoid arthritis.

Fever of Unknown Origin With Normal Inflammatory Markers Due to Latent Pulmonary Embolism and Deep Vein Thrombosis: A Case Report.

An 86-year-old woman who was hospitalized due to cerebral hemorrhage developed an intermittent fever of up to 39.3°C. A computed tomography angiography of the chest with venous runoff to the legs showed pulmonary embolism (PE) and deep vein thrombosis (DVT) of the legs. Intravenous heparin rapidly reduced the fever, indicating that these thrombi were the primary cause of her fever. During her course, white blood cell count and serum C-reactive protein levels were always within normal limits. This case suggested that latent PE and DVT can be a cause of intermittent fever with normal inflammatory markers.

The rapid efficacy of abatacept in a patient with rheumatoid vasculitis.

We report a case of rheumatoid vasculitis (RV) that responded well to abatacept, a cytotoxic T lymphocyte-associated antigen 4 (CTLA4)-immunoglobulin fusion protein. A 38-year-old woman developed RV despite treatment with methotrexate and tumor necrosis factor (TNF) inhibitors. The effects of steroid therapy, immunoabsorption plasmapheresis, and interleukin-6 inhibitor were insufficient, however, administration of abatacept rapidly improved her clinical symptoms with almost normalization of the immunological findings. This is the first published case report of the successful treatment of RV with abatacept.

Palmar Fasciitis and Polyarthritis Syndrome Associated with Lung Adenocarcinoma.

Palmar fasciitis and polyarthritis syndrome (PFPAS) is a rare paraneoplastic rheumatic disease with characteristic features. We herein report a 77-year-old man with lung adenocarcinoma and contralateral pulmonary metastasis receiving chemotherapy who presented with progressive symmetrical flexion contractures associated with palmar fascial thickening and arthritis of both hands and shoulders. He was diagnosed with PFPAS as paraneoplastic manifestations. Salazosulfapyridine was not effective, but 15 mg/day of oral prednisolone improved his symptoms. Physicians should consider PFPAS and rule out malignancy in patients with arthritis in the extremities and flexion contractures associated with palmar fascial thickening.

Feedback Control of the Arachidonate Cascade in Osteoblastic Cells by 15-deoxy-Delta-Prostaglandin J(2).

15-deoxy-Delta(12,14)-prostaglandin J(2) (15d-PGJ(2)) and an anti-diabetic thiazolidinedione, troglitazone (TRO) are peroxisome proliferator-activated receptor (PPAR)-gamma ligands, which regulate immuno-inflammatory reactions as well as adipocyte differentiation. We previously reported that 15d-PGJ(2) can suppress interleukin (IL)-1beta-induced prostaglandin E(2) (PGE(2)) synthesis in synoviocytes of rheumatoid arthritis (RA). IL-1 also stimulates PGE(2) synthesis in osteoblasts by regulation of cyclooxygenase (COX)-2 and regulates osteoclastic bone resorption in various diseases such as RA and osteoporosis. In this study, we investigated the feedback mechanism of the arachidonate cascade in mouse osteoblastic cells, MC3T3-E1 cells, which differentiate into mature osteoblasts. Treatment with 15d-PGJ(2) led to a significant increase in IL-1alpha-induced COX-2 expression and PGE(2) production in a dose dependent manner. The effect of 15d-PGJ(2) was stronger than that of TRO. However, it did not affect the expression of COX-1. In addition, cell viability of MC3T3-E1 cells was not changed in the condition we established. This means that 15d-PGJ(2) exerts a positive feedback regulation of the arachidonate cascade of PGE(2) in osteoblastic cells. These results may provide important information about the pathogenesis and treatment of bone resorption in a variety of diseases such as RA and osteoporosis.

Eicosapentaenoic Acid suppresses the proliferation of synoviocytes from rheumatoid arthritis.

Eicosapentaenoic acid (EPA) is essential for normal cell growth, and may play an important role in inflammatory and autoimmune disorders including rheumatoid arthritis. We investigate that EPA could suppress the proliferation of fibroblast like synoviocytes in vitro. We treated synoviocytes with 1 to 50 microM EPA and measured cell viabilities by the modified MTT assay. We sorted the number of them in sub G1 stage by fluorescence-activated cell sorting caliber. And we stained them by light green or Hoechst 33258, and investigate microscopic appearance. The cell viabilities were decreased at 30 microM, 40 microM, and 50 microM of EPA comparing to 0 microM of EPA. The half maximal concentration of synoviocytes inhibition was approximately 25 microM. At day 1 and day 3, cell number was also decreased at 50 microM EPA comparing to control. FACS caliber indicated the number of synoviocytes in sub G1 stage did not increase in each concentration of EPA. Hoechst staining indicated normal chromatin pattern and no change in a nuclear morphology both in EPA treated synoviocytes and in untreated synoviocytes. These findings suggest that EPA could suppress the proliferation of synoviocytes in vivo dose dependently and time dependently, however, the mechanism is not due to apoptosis.

SKL-2841, a dual antagonist of MCP-1 and MIP-1 beta, prevents bleomycin-induced skin sclerosis in mice.

Systemic sclerosis (SSc) is a connective tissue disease characterized by fibrosis and excessive collagen deposition in the skin and various internal organs. In early stages of SSc, the dermis reveals infiltration of inflammatory cells associated with increased collagen synthesis. SKL-2841 was initially synthesized as a novel small molecule antagonist of MCP-1. In this study, we indicated that SKL-2841 also exerts anti-chemotactic activity for MIP-1 beta in mouse spleen cells. In the early stages of bleomycin-induced skin lesions, immunohistochemical analysis showed the expression of both MCP-1 and MIP-1 beta in dermal inflammatory cells. Moreover, intraperitoneal administration of SKL-2841 suppressed the infiltration of inflammatory mononuclear cells and polymorphonuclear cells in the acute phase and also significantly suppressed fibrillization in the chronic phase in bleomycin-induced scleroderma, compared with PBS treatment. These findings suggest that SKL-2841 has potential as a compound for the treatment of conditions associated with skin fibrosis such as SSc.

A case report of tumor necrosis factor-alpha antibody-induced thrombocytopenia associated with emerging IgM anticardiolipin antibody in patients with scleroderma overlap/rheumatoid arthritis.

It is commonly believed that infliximab-induced anticardiolipin antibody belongs to the IgM subclass but not the IgG subclass and that the IgM subclass could not produce clinical symptoms. However, we had a patient with scleroderma overlap/rheumatoid arthritis who developed thrombocytopenia associated with the appearance of IgM anticardiolipin antibody after treatment with infliximab. This is a report of a rare case that should make us aware of the possibility of the development of thrombocytopenia with the appearance of IgM anticardiolipin antibody induced by infliximab.

Combination therapy of prednisolone and mizoribine improves cryoglobulinemic vasculitis with purpura and skin ulcers.

Conventional treatment is not standardized for hepatitis C virus-negative cryoglobulinemia, but corticosteroids, immunosuppressive agents, and plasma exchange typically improved the symptoms. Mizoribine is an immunosuppressive agent that was developed in Japan and has been found to inhibit the proliferation of lymphocytes, especially B cells. We have encountered an elder patient who had hepatitis C virus-negative, type II cryoglobulinemic vasculitis with leg purpura and skin ulcers. Her symptoms improved and cryoglobulin disappeared by the combination therapy of prednisolone and mizoribine. We speculate the action mechanism of this therapy is due to immunosuppressive effects including up-regulation of the efficacy of prednisolone by mizoribine.

Mucin from rheumatoid arthritis synovial fluid enhances interleukin-6 production by human peripheral blood mononuclear cells.

The carbohydrate chains represented by mucins (MUCs) are expressed by a variety of normal and malignant secretory epithelial cells and induce a variety of immunoreactions. To find new mucins related to the pathogenesis of rheumatoid arthritis (RA), we examined high-molecular-weight molecules inducing cytokines on human peripheral blood mononuclear cells (PBMCs) in synovial fluid from affected joints. We found a high-molecular-weight substance that induces interleukin 6 production on PBMCs in RA synovial fluid on gel filtration. MUC-1 was present in the resulting fractions, although they had been purified by CsCl density gradient centrifugation. We also found that MUC-1 was expressed on synovial cells and infiltrating inflammatory mononuclear cells on the sublining layer and lymphoid follicles in RA synovial tissues. CD68-positive superficial synovial cells colocalized with MUC-1 and CD68-positive macrophages were in contact with MUC-1-positive mononuclear cells. These findings imply that mucins, including MUC-1, may be related to immunoinflammatory reactions in the pathogenesis of RA.

15-Deoxy-Δ¹²,¹4 prostaglandin J2 reduces the formation of atherosclerotic lesions in apolipoprotein E knockout mice.

AIM: 15-deoxy-Δ¹²,¹4 prostaglandin J2 (15d-PGJ2) is a ligand of peroxisome proliferator-activated receptor γ (PPARγ) having diverse effects such as the differentiation of adipocytes and atherosclerotic lesion formation. 15d-PGJ2 can also regulate the expression of inflammatory mediators on immune cells independent of PPARγ. We investigated the antiatherogenic effect of 15d-PGJ2. METHODS: We fed apolipoprotein (apo) E-deficient female mice a Western-type diet from 8 to 16 wk of age and administered 1 mg/kg/day 15d-PGJ2 intraperitoneally. We measured atherosclerotic lesions at the aortic root, and examined the expression of macrophage and inflammatory atherosclerotic molecules by immunohistochemical and real-time PCR in the lesion. RESULTS: Atherosclerotic lesion formation was reduced in apo E-null mice treated with 15d-PGJ2, as compared to in the controls. Immunohistochemical and real-time PCR analyses showed that the expression of MCP-1, TNF-α, and MMP-9 in atherosclerotic lesions was significantly decreased in 15d-PGJ2 treated mice. The 15d-PGJ2 also reduced the expression of macrophages and RelA mRNA in atherosclerotic lesions. CONCLUSION: This is the first report 15d-PGJ2, a natural PPARγ agonist, can improve atherosclerotic lesions in vivo. 15d-PGJ2 may be a beneficial therapeutic agent for atherosclerosis.

Allograft inflammatory factor-1 is overexpressed and induces fibroblast chemotaxis in the skin of sclerodermatous GVHD in a murine model.

Allograft inflammatory factor (AIF)-1 has been identified in chronic rejection of rat cardiac allografts and is thought to be involved in the immune response. We previously showed that AIF-1 was strongly expressed in synovial tissues in rheumatoid arthritis and that rAIF-1 increased the IL-6 production of synoviocytes and peripheral blood mononuclear cells. Recently, the expression of AIF-1 has been reported in systemic sclerosis (SSc) tissues, whose clinical features and histopathology are similar to those of chronic graft-vs-host disease (GVHD). To clarify the pathogenic mechanism of fibrosis, we examined the expression and function of AIF in sclerodermatous (Scl) GVHD mice. We demonstrated that immunoreactive AIF-1 and IL-6 were significantly expressed in infiltrating mononuclear cells and fibroblasts in thickened skin of Scl GVHD mice compared with control. The immunohistochemical findings were confirmed by Western blot analysis. Wound healing assay also revealed that rAIF-1 increased the migration of normal human dermal fibroblasts (NHDF) directly, but cell growth assay did not show that rAIF-1 increased the proliferation of them. These findings suggest that AIF-1, which can induce the migration of fibroblasts and the production of IL-6 in affected skin tissues, is an important molecule promoting fibrosis in GVHD. Although the biological function of AIF-1 has not been completely elucidated, AIF-1 can induce IL-6 secretion on mononuclear cells and fibroblast chemotaxis. AIF-1 may accordingly provide an attractive new target for antifibrotic therapy in SSc as well as Scl GVHD.

Loxoprofen Sodium, a Non-Selective NSAID, Reduces Atherosclerosis in Mice by Reducing Inflammation.

Recently, it is suggested that the use of nonsteroidal anti-inflammatory drugs (NSAID) may contribute to the occurrence of cardiovascular events, while the formation of atherosclerotic lesions is related to inflammation. Loxoprofen sodium, a non-selective NSAID, becomes active after metabolism in the body and inhibits the activation of cyclooxygenase. We fed apoE(-/-) mice a western diet from 8 to 16 weeks of age and administered loxoprofen sodium. We measured atherosclerotic lesions at the aortic root. We examined serum levels of cholesterol and triglycerides with HPLC, platelet aggregation, and urinary prostaglandin metabolites with enzyme immune assay. Atherosclerotic lesion formation was reduced to 63.5% and 41.5% as compared to the control in male and female apoE(-/-) mice treated with loxoprofen sodium respectively. Urinary metabolites of prostaglandin E(2), F(1α), and thromboxane B(2), and platelet aggregation were decreased in mice treated with loxoprofen sodium. Serum levels of cholesterol and triglycerides were not changed. We conclude that loxoprofen sodium reduced the formation of early to intermediate atherosclerotic lesions at the proximal aorta in mice mediated by an anti-inflammatory effect.

A case of lupus nephritis improved after appropriately adjusting the dosage of mizoribine.

A 29-year-old male presenting nephrotic syndrome and facial skin erythema was admitted to our hospital in September of 2000. We diagnosed him as having systemic lupus erythematosus (SLE) accompanied by lupus nephritis (WHO class V). The disease activity had decreased after treatment with methylprednisolone (m-PSL) pulse therapy, which was followed by oral PSL. Thereafter, when tapering the dosage from 60 to 30 mg/day, the lupus nephritis flared up and he was re-hospitalized in February of 2001. After successful retreatment with m-PSL pulse therapy followed by the tapering of the dosage from 60 to 30 mg/day, we used mizoribine (MZR) as a combination therapy. The lupus nephritis flared up again after tapering down to 17.5 mg/day of PSL. Then, we changed the MZR dosage from 150 mg/day in three divided daily doses to 200 mg/day in two divided daily doses. This modification increased the peak blood concentration (Cmax) of MZR from 0.63 to 1.55 microg/ml. At present, we have been able to successfully taper the dosage to 7.5 mg/day of oral PSL and the patient has achieved a state of remission without any side effects. Monitoring of the serum concentration of MZR is thus considered to be important for achieving effective therapy of SLE, especially for steroid-resistant lupus nephritis. If the serum concentration of MZR does not reach an effective level, then the dosage of MZR should be adjusted appropriately in order to maintain an adequate serum concentration of MZR.

siRNA targeting PLK-1 induces apoptosis of synoviocytes in rheumatoid arthritis.

Polo-like kinase-1 (PLK-1) is a member of the PLK family and participates in the control of cell mitosis. Here, we show that immunoreactive PLK-1 is strongly expressed in synoviocytes and some infiltrative mononuclear cells in synovial tissues from patients with rheumatoid arthritis (RA), while patients with osteoarthritis and injury show little or no expression of PLK-1 in synovial tissues. Western blot analysis shows that PLK is expressed and its expression is enhanced by IL-1beta in RA synoviocytes. IL-1beta also enhanced the cell growth of RA synoviocytes. Moreover, siRNA targeted against PLK-1 significantly decreases the expression of PLK-1 of RA synoviocytes stimulated by IL-1beta and suppresses the proliferation of these synoviocytes through apoptosis. These findings suggest that PLK-1 plays a critical role in the proliferation of RA synoviocytes leading to bone destruction, and siRNA against PLK-1 is potentially useful for the treatment of RA.

A critical role for allograft inflammatory factor-1 in the pathogenesis of rheumatoid arthritis.

Rheumatoid arthritis (RA) is characterized by massive synovial proliferation, angiogenesis, subintimal infiltration of inflammatory cells and the production of cytokines such as TNF-alpha and IL-6. Allograft inflammatory factor-1 (AIF-1) has been identified in chronic rejection of rat cardiac allografts as well as tissue inflammation in various autoimmune diseases. AIF-1 is thought to play an important role in chronic immune inflammatory processes, especially those involving macrophages. In the current work, we examined the expression of AIF-1 in synovial tissues and measured AIF-1 in synovial fluid (SF) derived from patients with either RA or osteoarthritis (OA). We also examined the proliferation of synovial cells and induction of IL-6 following AIF-1 stimulation. Immunohistochemical staining showed that AIF-1 was strongly expressed in infiltrating mononuclear cells and synovial fibroblasts in RA compared with OA. Western blot analysis and semiquantitative RT-PCR analysis demonstrated that synovial expression of AIF-1 in RA was significantly greater than the expression in OA. AIF-1 induced the proliferation of cultured synovial cells in a dose-dependent manner and increased the IL-6 production of synovial fibroblasts and PBMC. The levels of AIF-1 protein were higher in synovial fluid from patients with RA compared with patients with OA (p < 0.05). Furthermore, the concentration of AIF-1 significantly correlated with the IL-6 concentration (r = 0.618, p < 0.01). These findings suggest that AIF-1 is closely associated with the pathogenesis of RA and is a novel member of the cytokine network involved in the immunological processes underlying RA.

Copper chelation with tetrathiomolybdate suppresses adjuvant-induced arthritis and inflammation-associated cachexia in rats.

Tetrathiomolybdate (TM), a drug developed for Wilson's disease, produces an anti-angiogenic and anti-inflammatory effect by reducing systemic copper levels. TM therapy has proved effective in inhibiting the growth of tumors in animal tumor models and in cancer patients. We have hypothesized that TM may be used for the therapy of rheumatoid arthritis and have examined the efficacy of TM on adjuvant-induced arthritis in the rat, which is a model of acute inflammatory arthritis and inflammatory cachexia. TM delayed the onset of and suppressed the severity of clinical arthritis on both paw volume and the arthritis score. Histological examination demonstrated that TM significantly reduces the synovial hyperplasia and inflammatory cell invasion in joint tissues. Interestingly, TM can inhibit the expression of vascular endothelial growth factor in serum synovial tissues, especially in endothelial cells and macrophages. Moreover, the extent of pannus formation, which leads to bone destruction, is correlated with the content of vascular endothelial growth factor in the serum. There was no mortality in TM-treated rat abnormalities. TM also suppressed inflammatory cachexia. We suggest that copper deficiency induced by TM is a potent approach both to inhibit the progression of rheumatoid arthritis with minimal adverse effects and to improve the well-being of rheumatoid arthritis patients.