Hidetaka Ishino

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.

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-α 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 Wilsons 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.

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.

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.

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.

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 E2, F1α, and thromboxane B2, 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.

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.

Pneumatosis intestinalis and hepatic portal venous gas caused by gastrointestinal perforation with amyloidosis.

To the Editor: Hepatic portal venous gas (HPVG) is a rare sign to demonstrate the existence of intraportal gas with severe disorders such as bowel necrosis. Pneumatosis intestinalis (PI) is the pathology in which a lot of pneumatic cysts exist in a gut wall, and this is the indication associated with the bowel damage like necrosis. We experienced the rare case with both HPVG and PI caused by secondary amyloidosis with rheumatoid arthritisis, who recovered by conservative treatment. A 63-year-old woman with rheumatoid arthritis (RA) for about 10 years has been followed up by no treatment. Oral administration of bucillamine for RA was started in 1999. A steroid intra-articular injection, treatment by methotrexate oral administration were performed afterward, too, but had difficulty with control. In March 2005, she canceled treatment of then herself, and chose treatment by Chinese medicine, but after all, she came to show diarrhea, a vomiting symptom from July, and she was hospitalized because of her symptom aggravation in October. It led to diagnosis of secondary amyloidosis associated with RA by endoscopic examination of the colon when she was hospitalized with the symptom again in January 2006. During hospitalization, she showed fresh blood bloody excrement and we performed abdominal computed tomography. It showed pneumatic presence in liver, pancreas, a gut wall, and free air intraperitoneally, and so we diagnosed it as HPVG and PI caused by lower digestive tract perforation (Figs. 1, 2). The gas disappeared by conservative treatment after half day. In many cases with conservative treatment, disappearance of HPVG and PI are found in an early stage (24 to 48h). In this case, the possible pathologic mechanism is as follows: when bowel pressure kept in a high state and gastrointestinal perforation occurred, air entered at the failed blood vessel and moved to the portal venous system. A lot of air was diffusely found in liver and pancreas in this image, but we did not recognize exacerbation of liver function and suggestive data of pancreatitis in blood examination, and those of peritonitis with intestinal perforation, so she recovered with only conservative treatment in an early stage of PI. PI is associated with various diseases: ileus, osmotic pressure enhancement, obstructive pulmonary disease, necrotizing enterocolitis, etc. HPVG is caused by mucosal damage, bowel distension, sepsis, and so on. However, amyloidosis is also one of the causes of HPVG and PI, there were extremely few reports of HPVG FIGURE 1. Pneumatic presence was in pancreas and a gut wall. Arrows indicate free air intraperitoneally.