Masahiro Ohsuga

Interleukin 15 activity in the rectal mucosa of inflammatory bowel disease

BACKGROUND & AIMS Interleukin (IL)-15 has been found to share many immunoregulatory activities in lymphocytes with IL-2. The aim of this study was to investigate IL-15 activity in organ cultures, localization of IL-15 messenger RNA (mRNA), and proliferation of lamina propria mononuclear cells (LPMCs) in response to recombinant IL-15 using the mucosal tissues obtained from patients with inflammatory bowel disease (IBD). METHODS The contents of IL-15, tumor necrosis factor alpha, and IL-2 in the culture supernatant of the rectal mucosal tissues were determined by an enzyme-linked immunosorbent assay. Expression of IL-15 mRNA was analyzed by in situ hybridization, and proliferative response of LPMCs to recombinant IL-15 was determined by [3H]thymidine incorporation into DNA. RESULTS Significantly greater IL-15 activity was detected in active IBD, and this elevation was also observed in inactive ulcerative colitis. In contrast, greater tumor necrosis factor alpha activity was observed only in active IBD, and IL-2 was not detected in organ cultures. In situ hybridization showed IL-15 mRNA in macrophages and epithelial cells in active IBD specimens, and recombinant IL-15 induced a dose-dependent proliferative response in LPMCs. CONCLUSIONS Mucosal IL-15 may be involved in the pathogenesis of IBD as one of the important mediators in activation of mucosal immune cells.

Interleukin‐6 and soluble interleukin‐6 receptor in the colonic mucosa of inflammatory bowel disease

Background : Interleukin‐6 (IL‐6) has multiple immunological effects on a wide variety of cells and tissues. The expression of IL‐6 and IL‐6 receptor (IL‐6R) may be important to the pathogenesis of inflammatory bowel disease (IBD).

Mucosal Chemokine Activity in helicobacter pylori Infection

We examined secretion, mRNA expression, and histologic localization of interleukin-8 (IL-*) and growth-related gene product-alpha (GRO alpha) in the Helicobacter pylori-infected gastric antral mucosa. Antral biopsies were obtained from an area of endoscopically intact mucosa. Significantly higher levels of IL-8 and GRO alpha were secreted in organ cultures from patients with H. pylori infection, and their elevation was prominent in patients with duodenal ulcer. There was a significant association between these alpha-chemokine levels and histologic grades of activity, inflammation, and H. pylori density. In fresh antral biopsies, IL-8 and GRO alpha mRNA expression was detected more frequently in H. pylori-infected patients compared with those without infection. Immunofluorescence microscopy showed localization of IL-8 and GRO alpha proteins in gastric epithelial cells and infiltrating CD68+ macrophages. In the chemotaxis assay, a significant positive correlation was found between neutrophil migration induced by the organ culture supernatants and their contents of IL-8 and GRO alpha. After H. pylori eradication, a significant decrease was observed in IL-8 and GRO alpha levels detected in organ cultures. In conclusion, mucosal alpha-chemokine activity correlates well with histologic severity of H. pylori-associated antral gastritis and can be used to predict the effects of H. pylori eradication therapy.

Mucosal macrophage inflammatory protein‐1α activity in Helicobacter pylori infection

Mucosal chemokines are considered to be important in the pathogenesis of Helicobacter pylori‐associated gastritis. The aims of this study are to examine the levels of macrophage inflammatory protein‐1α (MIP‐1α) in organ cultures, the expression of MIP‐1α mRNA and the cellular source of MIP‐1α, using the antral mucosal specimens obtained from H. pylori‐positive and ‐negative patients. Enzyme‐linked immunosorbent assay was used to measure the levels of MIP‐1α in organ cultures of mucosal tissues and cell cultures of fractionated mucosal cells. The expression of MIP‐1α mRNA and protein was analysed in fresh biopsy tissues with reverse transcriptase–polymerase chain reaction (RT‐PCR) and double immunofluorescence microscopy, respectively. The mucosal specimens obtained from H. pylori‐positive patients exhibited significantly higher values of MIP‐1α activity in organ cultures with increased numbers of CD68+ macrophages, myeloperoxidase+ neutrophils and mononuclear cells in the lamina propria compared with those from H. pylori‐negative patients. The RT‐PCR analysis detected MIP‐1α mRNA in more than 50% of the specimens with H. pylori infection, but not in those without infection. In cell cultures, the macrophage fraction contained substantially higher amounts of MIP‐1α on a per cell basis than the lymphocyte fraction and MIP‐1α activity was not detected in cultures of gastric epithelial cells. This observation was also confirmed by a double immunofluorescence microscopic study in which most (> 90%) MIP‐1α‐positive infiltrating cells were CD68+ macrophages. This study indicates that synthesis and secretion of MIP‐1α are increased in H. pylori‐infected antral mucosa and that mucosal macrophages are the main cell type responsible for this phenomenon.

Anti-CagA Immunoglobulin G Responses Correlate with Interleukin-8 Induction in Human Gastric Mucosal Biopsy Culture

ABSTRACT Helicobacter pylori persists in the human stomach despite eliciting both cellular and humoral immune responses and inducing proinflammatory cytokines. To determine whether local humoral and cytokine responses are related to each other and to histologic responses, we studied 66 Japanese patients who underwent gastroscopy. Using specific enzyme-linked immunosorbent assays, we examined gastric antral mucosal-organ biopsy culture supernatants to assess interleukin-6 (IL-6) and interleukin-8 (IL-8) levels and antibody responses to H. pylori whole-cell antigens CagA, HspA, and HspB. Of the patients studied, 11 were H. pylori negative and 55 were H. pylori positive; by PCR, all strains werecagA+. As expected, compared to H. pylori-negative patients, H. pylori-positive patients had significantly higher humoral responses to all H. pyloriantigens and had higher IL-8 (47.8 ± 3.5 versus 10.1 ± 4.3 ng/mg of biopsy protein; P < 0.001) and IL-6 levels (2.8 ± 0.3 versus 0.26 ± 0.2 ng/mg of protein;P < 0.001). Among the H. pylori-positive patients, supernatant anti-CagA immunoglobulin G (IgG) levels were significantly associated with H. pylori density (P < 0.005) and neutrophil infiltration (P < 0.005) scores. Anti-CagA immunoglobulin A levels were correlated with intestinal metaplasia (P < 0.05). Mononuclear cell infiltration scores were significantly associated with supernatant IL-6 levels (P < 0.005) and with IgG responses to whole-cell antigens (P < 0.05). Supernatant IL-8 levels were significantly associated with anti-CagA IgG (r = 0.75, P < 0.001). Anti-CagA responses correlated with neutrophil infiltration, intestinal metaplasia, H. pylori density, and IL-8 levels, suggesting that the absolute levels of these antibodies may be markers for gastric inflammation and premalignant changes in individual hosts.

Mucosal Macrophage Inflammatory Protein-1α Levels Are Increased in Helicobacter pylori Infection

We examined the relationship between the levels of macrophage inflammatory protein 1alpha (MIP-1alpha) and interleukin-8 (IL-8) in organ cultures of antral mucosal tissues, background gastroduodenal diseases, and grades of histologic gastritis. Significantly higher levels of MIP-1alpha and IL-8 were detected in patients with H. pylori infection than in those without infection. In H. pylori-positive patients, mucosal specimens from patients with peptic ulcer disease showed higher levels of MIP-1alpha and IL-8 than the specimens obtained from patients with erosive gastritis or those from endoscopically normal mucosa, and this was particularly pronounced in patients with duodenal ulcer. There were positive correlations between MIP-1alpha and IL-8 levels and histologic grades of activity, inflammation, and H. pylori density as defined by the Sydney system. However, the degree of association with the inflammatory cell count was different between these two chemokines. MIP-1alpha levels had a stronger association with mononuclear cells than with neutrophils, whereas IL-8 levels showed an association with neutrophils and mononuclear cells to an almost equal degree. These results suggest that MIP-1alpha and IL-8 may play important roles as inflammatory mediators in the pathogenesis of histologically proven H. pylori-associated gastritis.

Production of anti-CagA IgG correlates with IL-8 induction in human gastric mucosal organ culture

The frequency of gastric acid breakthrough and accompanying esophageal reflux in patients with GERD is not known. Aim: To determine the prevalence of noctumal gastric acid breakthrough and associated distal esophageal reflux in patients with GERD who are treated with PPI. Methods: Records from the esophageal lab from 1989-1997 were reviewed to determine the number of patients having pH metry while on PPI BID. Fifteen patients with Barretts (13 males; mean age 53 yr, range 29-73 yr) and 60 patients with GERD but no Barretts (25 males; mean age 47 yr, range 20-81 yr) were studied by ambulatory dual electrode (esophageal and gastric) pH testing on PPI BID. Supine gastric acid breakthrough defined as pH 1 hour in supine position, and esophageal reflux defined as > 0% time supine distal esophageal pH < 4 during breakthrough period. Results: The prevalence of nocturnal supine gastric acid breakthrough and accompanying esophageal acid reflux is shown below.