Hiroyuki Tamaki

Elimination of local macrophages in intestine prevents chronic colitis in interleukin-10-deficient mice.

Uncontrolled activation of T cells and macrophages is involved in the development of inflammatory bowel disease (IBD). However, the precise role of intestinal macrophages for development of IBD is till unclear. To investigate the role of local macrophages for development of IBD, we developed poly-D, L-lactic acid microspheres containing dichloromethylene diphosphonate, which was specifically taken up by macrophages and depleted them, and then the animal model for human IBD was treated with this reagent. We have shown that rectal administration of the microspheres reduced the numbers of resident macrophages in the intestinal lymphoid follicles of interleukin-10-deficient mice. Importantly, depletion of intestinal macrophages was associated with suppression of development of chronic colitis. These results suggest that local macrophages in the intestine play a critical role in the development of chronic colitis in an animal model for IBD. Our study implies that elimination of resident macrophages in the intestine may become a therapeutic approach to IBD.

Long-term effect of tacrolimus therapy in patients with refractory ulcerative colitis

Background  Little is known about long‐term outcome of tacrolimus therapy for ulcerative colitis.

A Case of Autoimmune Pancreatitis Associated with Sclerosing Cholangitis, Retroperitoneal Fibrosis and Sjögren’s Syndrome

We report a very rare case of autoimmune pancreatitis (AIP) associated with sclerosing cholangitis, retroperitoneal fibrosis and Sjögren’s syndrome. The patient had an enlarged pancreas, and autoantibodies were detected in the serum. Serum IgG and IgG4 concentrations were also elevated. Endoscopic retrograde cholangiopancreatography revealed an irregular narrowing of the main pancreatic duct from the head to the body and sclerotic change in the intrapancreatic common bile duct, which later extended to the intrahepatic bile ducts. In addition, histological examination of the liver revealed lymphocytic sclerosis around the bile ducts, similar to the histology in the pancreas of AIP. Retroperitoneal tumors were diagnosed as retroperitoneal fibrosis by histological examination. Serological and functional abnormalities suggestive of Sjögren’s syndrome were detected, and histological findings of the lip were compatible with Sjögren’s syndrome. Immunohistochemistry of each lesion disclosed that most of the infiltrating lymphocytes were T cells with similar levels of both CD4+ and CD8+ cells. Moreover, some of the infiltrating plasma cells were positive for anti-IgG4 monoclonal antibody. These diseases were dramatically improved by steroid therapy. Although the pathophysiology of AIP is still unclear, the present case suggests a common pathophysiological mechanism for AIP, sclerosing cholangitis, retroperitoneal fibrosis and Sjögren’s syndrome.

Involvement of myeloid dendritic cells in the development of gastric secondary lymphoid follicles in Helicobacter pylori-infected neonatally thymectomized BALB/c mice

ABSTRACT We previously described an animal model of Helicobacter pylori-induced follicular gastritis in neonatally thymectomized (nTx) mice. However, it is still not clear whether antigen-presenting dendritic cells (DCs) in the stomach have a role in the development of secondary follicles in H. pylori-infected nTx mice. We investigated the distribution of DC subsets using this model and examined their roles. To identify lymphoid and myeloid DCs, sections were stained with anti-CD11c (pan-DC marker) in combination with anti-CD8α (lymphoid DC marker) or anti-CD11b (myeloid DC marker) and were examined with a confocal microscope. Expression of macrophage inflammatory protein 3α (MIP-3α), which chemoattracts immature DCs, was analyzed by real-time PCR and immunohistochemistry. Follicular dendritic cells (FDCs) were stained with anti-SKY28 antibodies. In noninfected nTx mice, a few myeloid and lymphoid DCs were observed in the bottom portion of the lamina propria, whereas in H. pylori-infected nTx mice, there was an increased influx of myeloid DCs throughout the lamina propria. FDC staining was also observed in the stomachs of members of the infected group. MIP-3α gene expression was upregulated in the infected nTx group, and the immunohistochemistry analysis revealed MIP-3α-positive epithelial cells. These data suggest that H. pylori infection upregulates MIP-3α gene expression in gastric epithelial cells and induces an influx of myeloid DCs in the lamina propria of the gastric mucosa in nTx mice. Myeloid DCs and FDCs might contribute to the development of gastric secondary lymphoid follicles in H. pylori-infected nTx mice.

Specific antibodies against recombinant protein of insertion element 900 of Mycobacterium avium subspecies paratuberculosis in Japanese patients with Crohn's disease

Background: Mycobacterial avium subspecies paratuberculosis (MAP) infection has been hypothesized as an etiological factor of Crohns disease (CD). However, the involvement of MAP in the pathophysiology of CD is controversial. The aim of this study is to investigate whether MAP is involved in the pathogenesis of CD with the glutathione S‐transferase fusion recombinant protein encoding a portion of insertion element (IS) 900 (IS900‐GST), which is specific for MAP. Methods: Serum samples from the patients with CD (n = 50), ulcerative colitis (n = 40), colonic tuberculosis (n = 20), and non‐IBD controls (n = 44), were applied for solid‐phase enzyme‐linked immunosorbent assay (ELISA) to detect antibodies against MAP and Saccharomyces cerevisiae. IS900‐GST, which was made by the pGST‐4T‐2 vector inserted with polymerase chain reaction‐amplified IS900DNA, was used as an antigen of MAP. Moreover, we studied the relationship between antibodies against IS900‐GST and clinical characteristics. Results: ELISA showed that the serum level of immunoglobulin G and immunoglobulin A antibodies against IS900‐GST (anti‐IS900) in patients with CD were significantly higher than those with ulcerative colitis, colonic tuberculosis, and control subjects. The levels of anti‐IS900 tended to be higher in CD patients with small intestinal involvement than with colonic involvement alone. Anti‐IS900 in patients with penetrating‐ and stricture‐type CD was significantly higher than with inflammatory‐type CD. Furthermore, a negative correlation was found between the titer of anti‐IS900 and disease duration. Anti‐IS900 was not associated with surgical treatment nor was it associated with the use of immunosuppressants. No significant correlation was observed between the serum levels of anti‐IS900 and anti‐S cerevisiae antibody. Conclusions: This is the first demonstration of the ELISA system of detecting antibodies against IS900 in IBD patients. MAP could be involved in the pathophysiology of Japanese patients with CD.

Helicobacter felis-induced gastritis was suppressed in mice overexpressing thioredoxin-1

Thioredoxin-1 (TRX-1) is a redox-active protein involved in scavenging reactive oxygen species and regulating redox-sensitive transcription factors. TRX-1 is induced in various inflammatory conditions and shows cytoprotective action. We investigated the roles of TRX-1 in the host defense mechanism against Helicobacter felis (H. felis) infection. Transgenic (TG) mice overexpressing human TRX-1 and wild-type (WT) mice were orally inoculated with H. felis. After 2 months, histology, oxidative damage, and gene expression of several cytokines, including macrophage inflammatory protein-2 (MIP-2), a murine equivalent to interleukin (IL)-8, in the gastric mucosa were investigated. Furthermore, the effects of TRX-1 on oxidative stress and neutrophil migration were studied both in vivo and in vitro. The gastric mucosa was thickened in H. felis-infected WT mice, but not in infected TRX-1-TG mice. Histologically, all H. felis-infected WT mice developed moderate-to-severe gastritis, whereas the development of gastritis was significantly suppressed in infected TRX-1-TG mice. Oxidative damage markers, 8-hydroxy-2′-deoxyguanosine and malondialdehyde, increased in the stomach of infected WT mice, but not TRX-1-TG mice. Upregulation of IL-1β and tumor necrosis factor-α gene expression in H. felis-infected TRX-1-TG mice was significantly lower than in WT mice. However, upregulation of MIP-2 and IL-7 was not different between the two groups. TRX-1 suppressed oxidative cytotoxicity and DNA damage, and inhibited neutrophil migration both in vivo and in vitro. The present study suggests that overexpression of TRX-1 suppresses H. felis-induced gastritis by inhibiting chemotaxis of neutrophils and reducing oxidative stress.

The effect of tacrolimus (FK-506) on Japanese patients with refractory Crohn’s disease

BackgroundRecent evidence indicates that intravenous or oral therapy with tacrolimus (FK-506) is effective in treating patients with Crohn’s disease. We evaluated the usefulness of tacrolimus therapy for Japanese patients with refractory Crohn’s disease.MethodsFourteen adult Japanese patients with Crohn’s disease that was refractory to conventional therapies, including prednisolone (n = 5), azathioprine (n = 6), and infliximab (n = 5), were enrolled. Treatment with tacrolimus was started orally or intravenously and aimed for serum trough levels of 10–15 ng/ml. After the patients achieved clinical improvement, tacrolimus maintenance therapy was administered to maintain the trough level at 5–10 ng/ml.ResultsAll patients achieved remission or significant improvement 40 days after starting tacrolimus treatment. By 120 days after the start of therapy, 9 (64%) patients achieved remission, 2 patients (14%) achieved significant improvement, and only 3 patients (21%) relapsed. The relapsed patients were treated with infliximab therapy and achieved remission. Steroids were discontinued by the 5 patients who had taken steroids before the study began. Adverse effects of tacrolimus included a temporary increase in serum creatinine concentration (n = 1, 7%), hyperkalemia (n = 1, 7%), and tremor (n = 1, 7%).ConclusionsTacrolimus therapy is effective and well tolerated in patients with Crohn’s disease that is refractory to conventional therapies.

Efficacy of probiotic treatment with Bifidobacterium longum 536 for induction of remission in active ulcerative colitis: A randomized, double‐blinded, placebo‐controlled multicenter trial

We conducted a randomized, double‐blinded, placebo‐controlled trial to investigate the efficacy of Bifidobacterium longum 536 (BB536) supplementation for induction of remission in Japanese patients with active ulcerative colitis (UC).

Cytomegalovirus infection in patients with ulcerative colitis diagnosed by quantitative real-time PCR analysis

Cytomegalovirus (CMV) infection is an exacerbating factor in patients with ulcerative colitis (UC) (1–8). The prognosis of patients with UC complicated by CMV infection is generally poor if the infection is not recognized at an early stage (4, 8, 9). Therefore, it is important to consider the possibility of CMV infection and to make a rapid diagnosis when patients with UC do not respond to conventional corticosteroid therapy (6, 10). We describe here three patients with refractory UC complicated by CMV infection, which were diagnosed by quantitative real-time polymerase chain reaction (PCR) assay of CMV DNA in colonic tissue.

Immunogenetic analysis of gastric MALT lymphoma-like lesions induced by Helicobacter pylori infection in neonatally thymectomized mice

Most gastric mucosa-associated lymphoid tissue (MALT) lymphomas are caused by Helicobacter pylori (H. pylori) infection. We previously reported that acquired lymphoid follicles with germinal centers were induced by H. pylori infection in neonatally thymectomized (nTx) mice. In the present study, we developed gastric MALT lymphoma-like lesions in nTx mice by long-term H. pylori infection, and performed immunogenetic analyses. BALB/c mice were thymectomized on the 3rd day after birth. At 6 weeks of age, mice were orally infected with 108 H. pylori and serially killed 2, 4, 6, and 12 months later. Normal BALB/c and noninfected nTx mice served as controls. Follicle formation occurred after 2 months of H. pylori infection in the nTx mice. Follicle formation and infiltration of intraepithelial lymphocytes progressed in a time-dependent manner. Lymphoepithelial lesions, a characteristic feature of MALT lymphoma, also occurred in a time-dependent manner (100% at 12 months). Serum immunoelectrophoresis revealed a monoclonal band (M-protein) in 30% (3/10) of mice 6 months after infection. M-protein-positive mice had amplification of one or two IgM and/or IgG heavy-chain genes in the gastric B lymphocytes, as determined with polymerase chain reaction, suggesting mono- or oligoclonality. Overexpression of Bcl-XL protein was immunohistologically observed in the infiltrating B lymphocytes and in some follicular B lymphocytes in 80% (8/10) of the cases at 12 months. Thus, H. pylori infection is involved in the development of gastric MALT lymphoma-like lesions in nTx mice. Our mouse model is useful for clarifying the pathogenetic mechanism of gastric MALT lymphoma by H. pylori infection.