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Pivotal roles of interleukin-6 in transmural inflammation in murine T cell transfer colitis.

Breakdown of normal mucosal immunity is one of the major causes for inflammatory bowel disease. Interleukin (IL)-6 is a proinflammatory cytokine produced aberrantly in various types of inflammation, but its role in inflammatory bowel disease is still obscure. Hence, we analyzed the roles of IL-6 in the pathogenesis of murine T cell transfer colitis, whose histopathology resembles Crohn's disease. The transfer of CD4+CD45RBhigh T cells into severe combined immunodeficiency mice induced the infiltration of T cells and macrophages, and the gene expression of CC chemokine receptor (CCR)1, CCR2, CCR5, CXC chemokine receptor 3, their ligands, tumor necrosis factor-alpha, interferon-gamma, and IL-6 was progressively augmented as colitis developed. The incidence of transmural colitis was significantly reduced with a minimal decrease in the severity of colitis in recipients transferred with CD4+CD45RBhigh T cells derived from IL-6-deficient mice compared with those with wild-type mice. Moreover, the gene expression of several cytokines, chemokines, and matrix metalloproteinases was reduced significantly in recipients transferred with IL-6-deficient, mice-derived T cells. These observations suggested that T cell-derived IL-6 may augment the gene expression of several proinflammatory molecules, thereby causing transmural inflammation. Thus, IL-6 might be a promising target for treating transmural inflammation in Crohn's disease, which can lead to severe complications such as strictures, fissures, and fistulas.

Animals↗

MDR1 mRNA expressions in peripheral blood mononuclear cells of patients with ulcerative colitis in relation to glucocorticoid administration.

Overexpression of multidrug resistance (MDR) protein, P-glycoprotein (P-gp), on lymphocytes has been suggested to be implicated in the failure of glucocorticoid (GC) therapy in patients with ulcerative colitis (UC). However, whether the overexpression of P-gp in a class of patients with inflammatory bowel disease (IBD) is intrinsic or related to the administration of GC is unknown. Relative amounts of MDR1 mRNA expressed in peripheral blood mononuclear cells (PBMCs) were measured using the reverse-transcriptase polymerase chain reaction (RT-PCR) technique in 25 UC patients having no history of GC administration, 25 UC patients having experienced GC therapy, 19 patients with Crohn's disease (CD) with no history of GC therapy, and 27 healthy subjects. Relative amounts of MDR1 mRNA expressed in PBMCs were compared among the groups. The relationship between the amounts of MDR1 mRNA expressed, as well as the total dose of GC administered or the period of GC therapy in UC patients, was examined. The relative amounts of MDR1 mRNA expressed in PBMCs were not significantly different between the healthy subjects and CD patients or UC patients having no history of GC therapy. However, the mean MDR1 mRNA amount in PBMCs of UC patients having experienced GC therapy was significantly greater than that in PBMCs of UC patients with no history of GC administration (p = 0.0375). The amounts of MDR1 mRNA in PBMCs of UC patients having experienced GC therapy significantly correlated with the total dose of GCs administered (p = 0.0175). Overexpression of MDR1 mRNA in PBMCs of IBD patients is not intrinsic. However, high-dose administration of GCs for the treatment of UC may result in an increased expression of MDR1 mRNA, which may impair successful GC therapy in these patients.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

Investigation on lymphocyte subpopulations in the intestinal lamina propria in inflammatory bowel diseases.

Intestinal lamina proprial lymphocytes were enumerated in 13 patients with Crohn's disease (CD), 7 with ulcerative colitis (UC) and 9 control subjects with grossly normal bowel. The percentages and absolute numbers of B cells and complement receptor-bearing lymphocytes in the patients with UC did not differ significantly from those of the control group; but in CD, the percentages of these cells were significantly decreased despite that the absolute numbers were normal. The percentages and absolute numbers of T cells identified by E rosettes (regular and stable) were normal in both CD and UC. In both diseases, significantly increased percentages but normal absolute numbers of mature T cells were identified by monoclonal antibody staining with the CD3 reagent. There was an increased proportion of suppressor/cytotoxic T cells and a concomitant significant decrease of the helper to suppressor T-cell ratio (using either percentages or absolute numbers of cells) in tissues from patients with CD, but not with UC as compared with the control group. These results suggest that the imbalance of T-cell subpopulations in the intestinal lamina propria may play a role in the pathogenesis of CD.

Antibodies, Monoclonal↗

Lymphocyte glycogen content in various diseases.

The lymphocyte glycogen content has been measured semi-quantitatively by staining peripheral blood films by the periodic-acid-Schiff (P.A.S.) technique. The high values reported in chronic lymphatic leukaemia, lymphosarcoma, Hodgkin's disease, and infectious mononucleosis have been confirmed. High values have also been found in cases with chronic suppuration, ulcerative colitis, myelomatosis, and epithelial malignancies. Our results suggest that a high lymphocyte glycogen content may be produced by several different mechanisms and that the test is of little value in differential diagnosis.

Colitis, Ulcerative↗

The subpopulations of circulating white blood cells in inflammatory bowel disease.

A detailed analysis of the species of lymphocytes was carried out in 58 patients with inflammatory bowel disease (IBD). These individuals were further divided into 31 with Crohn's disease (CD) and 27 with ulcerative colitis (UC). There were 13 CD patients with only small bowel involvement called "regional enteritis" and 18 who had some degree of colonic involvement called "ileocolitis". Similarly, the UC group was subdivided into 9 patients with disease confined to the rectosigmoid area called "proctosigmoiditis" and 18 with more extensive involvement called "universal colitis". We also studied 13 patients who had undergone previous colectomy and ileostomy and 78 healthy age- and sex-matched controls. Although there was no increase in the absolute number of lymphocytes in patients with ileocolitis and universal colitis, the percentage of these cells was decreased because of an increase in both polymorphonuclear leukocytes and monocytes. In IBD and its subgroups, mean T lymphocytes, determined by the sheep red blood cell rosette technique, were not significantly different from the controls either in percentage or absolute number. Furthermore, no difference was noted between UC and CD. However, there seems to be a subpopulation of patients with UC or CD whose T cells are reduced below 1 SD of the mean. There was also no difference in the number of immunoglobulin-bearing B cells in both diseases; however, when the B cells were enumerated by their ability to rosette with antibody-complement-coated sheep cells (EAC), we found a marked decrease in percentage (P less than 0.001) and absolute number (P less than 0.0005) relative to the control population. The decrease bore a direct relation to the severity of the disease process and, although more marked in patients with UC, was present in CD also.

B-Lymphocytes↗

Antifolate actions of sulfasalazine on intact lymphocytes.

SASP, the drug most widely used for the treatment of Crohn's disease and ulcerative colitis, is a competitive inhibitor of intestinal folate metabolism and transport. Some of the therapeutic effects of the drug could be related to antifolate actions on lymphocytes, which predominate in the inflammatory reaction in inflammatory bowel diseases. Experiments were designed to examine the effect of SASP on folate-dependent systems in cultured lymphocytes. In rat spleen lymphocytes, THF-dependent conversion of glycine to serine was inhibited by SASP, with 50% inhibition occurring at 0.1 mM. Further evidence of folate antagonism was obtained with the dU suppression test, which depends on the function of a folate-dependent pathway in the de novo synthesis of DNA. Folate antagonists like methotrexate or folate depletion reduces the incorporation of dU into DNA and thus favors incorporation of [3H]thymidine into DNA by an alternate pathway. SASP inhibited the folate-dependent pathway in proliferating virally transformed human lymphocytes (Raji cells). To confirm that SASP acts as a folate antagonist in this system, THF was demonstrated to partly reverse the action of SASP. The significance of this antifolate action by SASP in intact lymphocytes deserves further study in relation to the actions of SASP in patients with inflammatory bowel disease.

Animals↗

Histopathological evaluation of colonic mucosal biopsy specimens in chronic inflammatory bowel disease: diagnostic implications.

In a prospective blind evaluation of multiple colonic mucosal biopsy specimens, 45 clinically well defined patients with chronic inflammatory bowel disease (21 Crohn's disease and 24 ulcerative colitis) and 16 control subjects (seven normal subjects and nine patients with diverticular disease) were studied to identify reproducible histopathological features which could distinguish chronic inflammatory bowel disease (CIBD) from non-CIBD and Crohn's disease from ulcerative colitis. Using kappa statistics 16 of 41 histological features were sufficiently reproducible for further stepwise discriminant analysis to differentiate between CIBD and non-CIBD, and between Crohn's disease and ulcerative colitis. Using the combination of three features (an increase of lymphocytes and plasma cells in the lamina propria, the presence of branching of crypts, and neutrophils in the crypt epithelium) we were able to distinguish CIBD from non-CIBD in 89% of the cases with high probability (p greater than 0.85). To separate Crohn's disease from ulcerative colitis three features (an excess of histiocytes in combination with a villous or irregular aspect of the mucosal surface and granulomas) had a high predictive value. Using these features 70% of Crohn's disease patients and 75% of ulcerative colitis patients were correctly classified with a high probability (p greater than 0.85). These findings indicate that the pathologist is dependent on the presence of only a few histological features for a reliable classification of Crohn's disease and ulcerative colitis.

Adult↗

[Incidence of intestinal gamma/delta T cells in children with celiac disease and ulcerative colitis].

Authors studied the numbers of T-cell receptor-alpha/beta, gamma/delta positive lymphocytes and the proportion of gamma/delta positive cells with a non-disulfide linked form of gamma/delta receptor in jejunal mucosa from 19 coeliatic children, in rectal specimens from 14 children with ulcerative colitis, as well as in specimens of 23 healthy controls. Monoclonal antibodies and a sensitive indirect peroxidase method were used. In the lamina propria and epithelium of a normal jejunum and rectum, as well as in the rectal and colonic mucosae of patients with ulcerative colitis only low numbers of gamma/delta positive cells were seen. In the lamina propria, in the surface epithelium, as well as, in the epithelium of the Lieberkühn crypts the number of gamma/delta positive cells were significantly higher than in the controls before treatment, during gluten free diet and after the gluten challenge. In the epithelium the absolute numbers of these cells remained constant during gluten elimination and provocation. The constantly elevated population of gamma/delta positive T-cells in coeliac disease might show their primary pathogenetic role in this disorder. The detection of elevated number of intraepithelial gamma/delta T-cells may have significance in the diagnosis of coeliac disease.

Biopsy↗

Mucosal IL-7-mediated immune responses in chronic colitis-IL-7 transgenic mouse model.

We have demonstrated that intestinal epithelial cells produce interleukin-7 (IL-7) and IL-7 serves as a regulatory factor for proliferation of mucosal lymphocytes. To clarify the mechanism by which locally produced IL-7 regulates mucosal lymphocytes and the role of mucosal IL-7 in colonic inflammation, we investigated IL-7 transgenic (IL-7 Tg) mice and demonstrated that IL-7 Tg mice developed acute and chronic colitis with histopathological similarity to ulcerative colitis in humans. In concert with our recent findings that IL-7 stimulates the proliferation of inactivated mucosal lymphocytes but eliminates activated lymphocytes in the inflamed mucosa of human ulcerative colitis. These findings suggest that chronic inflammation in the colonic mucosa is mediated by dysregulation of epithelial cell-derived IL-7 system.

Animals↗

Chronic intestinal inflammatory condition generates IL-10-producing regulatory B cell subset characterized by CD1d upregulation.

B cells possess a variety of immune functions that are involved in normal and abnormal immune responses, including autoimmune disorders. Through murine models of intestinal inflammation, we here demonstrate a B cell subset that is induced in gut-associated lymphoid tissues and is characterized by CD1d upregulation. This B cell subset appears under a chronic inflammatory environment, produces IL-10, and suppresses progression of intestinal inflammation by downregulating inflammatory cascades associated with IL-1 upregulation and STAT3 activation rather than by altering polarized T helper responses. This study indicates that B cells, by producing cytokines such as IL-10, can act as regulatory cells in immunologically mediated inflammatory reactions.

Animals↗

CD4+CD25bright T cells in human intestinal lamina propria as regulatory cells.

It is well known that immune responses in the intestine remain in a state of controlled inflammation, suggesting that not only active suppression by regulatory T cells plays an important role in the normal intestinal homeostasis, but also its dysregulation leads to the development of inflammatory bowel disease. In this study, we demonstrate that the CD4(+)CD25(bright) T cells reside in the human intestinal lamina propria (LP) and functionally retain regulatory activities. All human LP CD4(+) T cells regardless of CD25 expression constitutively expressed CTLA-4, glucocorticoid-induced TNFR family-related protein, and Foxp3 and proliferate poorly. Although LP CD4(+)CD25(-) T cells showed an activated and anergic/memory phenotype, they did not retain regulatory activity. In LP CD4(+)CD25(+) T cells, however, cells expressing CD25 at high levels (CD4(+)CD25(bright)) suppressed the proliferation and various cytokine productions of CD4(+)CD25(-) T cells. LP CD4(+)CD25(bright) T cells by themselves produced fewer amounts of IL-2, IFN-gamma, and IL-10. Interestingly, LP CD4(+)CD25(bright) T cells with regulatory T activity were significantly increased in patients with active inflammatory bowel disease. These results suggest that CD4(+)CD25(bright) T cells found in the normal and inflamed intestinal mucosa selectively inhibit the host immune response and therefore may contribute to the intestinal immune homeostasis.

Antigens, CD↗

[Oxidative injury and its defense system in vivo].

We and other researchers verified that excessively produced free radicals by neutrophils induce various diseases such as Behçet's disease, MCLS, SLE (neutrophil-stimulated lymphocytes), RA (synovial fluid neutrophils), Crohn's disease, colitis ulcerosa, and dermatitis herpetiformis (Dühring). Recently, it was reported that environmental toxic agents including herbicides such as paraquat, insecticides, nitrogen oxide, and ultraviolet radiation produce free radicals. Nitrogen oxide, a main product of the combustion of petroleum, is a prominent component of exhaust from automobiles. Generation of 1O2 by ultraviolet radiation has also increased by breaks in the earth's ozone layer induced by halogenated hydrocarbon gas. Various diseases have been induced by these agents such as malignancies, severe adult atopic dermatitis, complication of cataract and retinolysis with atopic dermatitis, skin cancer, male infertility, severe collagen diseases, and lung fibrosis. It was also found that PCB, methyl-Hg and Mn, Cd induce neuropathic diseases through the increase in free radical production. On the other hand, a self-defense system exists against oxidative injuries; high-molecular-weight antioxidants such as SOD, catalase, and GSH-Px, and low-molecular-weight antioxidants such as vitamin C, E, A, polyphenols, flavonoids, and catechin. As protection from oxidative injury, various antioxidant products have been developed, however, the development of SOD injection was given up by all the pharmaceutical companies in the world on account of ineffectiveness due to rapid excretion from the kidney, low affinity to the receptor and weak penetration into the cell. A.M. Michelson, a French biochemist succeeded in developing an effective bovine liposomal-encapsulated SOD solving these problems, however, he also gave it up since French government prohibited bovine products due to the prion virus. Regarding low-molecular-weight antioxidants, synthetic products generally show low affinity to human cell receptors, however, natural products also has demerits that abundant low-molecular-weight compounds with antioxidant activity that exist in the native materials as repeating subunits of high-molecular-weight polymers resulting in inactive forms. We have developed effective natural antioxidant by a unique treating procedure that includes heating with far infrared radiation of 4-14 microns wavelength, brewing with the fungus Aspergillus oryzae, and emulsification with similarly heated sesame oil. This formulation is based on our hypothesis that treatment of natural plant products with heating and brewing results in the liberation of abundant low-molecular-weight compounds with antioxidant activity that exist in an inactive form as repeating polymers as described above.

Adult↗

CD4+ CD25+ regulatory T lymphocytes inhibit microbially induced colon cancer in Rag2-deficient mice.

Inflammatory bowel diseases, including ulcerative colitis and Crohn's disease, increase the risk of colorectal cancer in humans. It has been recently shown in humans and animal models that intestinal microbiota and host immunity are integral in the progression of large bowel diseases. Lymphocytes are widely believed to prevent bacterially induced inflammation in the bowel, and lymphocytes are also critical in protecting against primary tumors of intestinal epithelia in mice. Taken together, this raises the possibility that lymphocytes may inhibit colon carcinogenesis by reducing bacterially driven inflammation. To examine the role of bacteria, lymphocytes, and inflammatory bowel disease in the development of colon cancer, 129/SvEv Rag-2-deficient and congenic wild-type mice were orally inoculated with a widespread enteric mouse bacterial pathogen, Helicobacter hepaticus, or sham-dosed with media only. H. hepaticus-infected Rag2-/-, but not sham-dosed Rag2-/- mice, rapidly developed colitis and large bowel carcinoma. This demonstrated a link between microbially driven inflammation and cancer in the lower bowel and suggested that innate immune dysregulation may have an important role in inflammatory bowel disease and progression to cancer. H. hepaticus-infected wild-type mice did not develop inflammation or carcinoma showing that lymphocytes were required to prevent bacterially induced cancer at this site. Adoptive transfer with CD4+ CD45RBlo CD25+ regulatory T cells into Rag-deficient hosts significantly inhibited H. hepaticus-induced inflammation and development of cancer. These results suggested that the ability of CD4+ T cells to protect against intestinal cancer was correlated with their ability to reduce bacterially induced inflammatory bowel disease. Further, regulatory T cells may act directly on the innate immune system to reduce or prevent disease. These roles for T cells in protection against colon carcinoma may have implications for new modes of prevention and treatment of cancer in humans.

Adoptive Transfer↗

Chronic murine colitis is dependent on the CD154/CD40 pathway and can be attenuated by anti-CD154 administration.

BACKGROUND & AIMS: Experimental colitis in most animal models is caused by dysregulation of T lymphocytes that display a T helper 1 (Th1) phenotype. CD154 (CD40L/gp39), a member of the tumor necrosis factor (TNF) family, is up-regulated on T cells on activation and has been shown to play a key role in the induction of a Th1 response. We investigated whether chronic experimental colitis is dependent on the CD154/CD40 pathway and whether disease can be prevented by anti-CD154 antibody treatment. METHODS: Two models of chronic colitis were used: CD45Rb(hi) cell transfer into recombination activation gene-deficient (Rag(-/-)) mice and bone marrow transplant of tgepsilon26 animals. In both models, mice were reconstituted with cells from CD154-deficient animals. In another series of experiments, wild-type CD45Rb(hi) T cell-reconstituted recipients were treated with anti-CD154, either from the start of the experiment or after onset of disease. RESULTS: T cells deficient in CD154 induced a milder clinical disease, less weight loss, and fewer histologic signs of colitis than wild-type cells. The level of interleukin 12 in the serum of CD154-deficient T-cell recipients was 5-fold less than that of wild-type cell recipients. Nevertheless, no signs of deviation from a Th1 phenotype were observed. Treatment with anti-CD154 antibodies substantially impaired disease development, even when started after the onset of colitis. CONCLUSIONS: The CD154/CD40 pathway plays a critical role in Th1-induced chronic experimental colitis. Blocking CD154, even after the onset of disease, ameliorates colitis but does not induce a T helper 2 (Th2) phenotype.

Animals↗

[Immunohistochemical studies of ulcerative colitis--expression of HLA-DR antigen by colonic epithelium and the role of dendritic cells in the lamina propria].

In 27 patients with ulcerative colitis the colonic mucosa was analyzed by an immunohistochemical technique. A quantitative evaluation for lymphocyte subsets shows significantly-increased numbers of CD3+ cells, CD4+ cells, CD8+ cells and Leu7+ cells in ulcerative colitis cases of histological grades 4 and 5 by Matts's classification comparing to controls. However, CD4/CD8 ratio in each histological grade of ulcerative colitis was similar to that in normal controls. The HLA-DR antigen on the colonic epithelium was frequently expressed in patients with grades 3 to 5 (84.2%), and in active patients (88.9%). The antigens were also expressed on the lamina propria mononuclear cells, which coincided with the distribution of S-100+ dendritic cells. Moreover double staining for S-100 antigen and IL-2R antigen revealed that most of the S-100+ dendritic cells were also IL-2R positive. These findings seem to provide evidence for the important role of lamina propria dendritic cells in the immunological pathogenesis of ulcerative colitis.

Colitis, Ulcerative↗