Z Ren

University of Münster, Muenster, North Rhine-Westphalia, Germany

Are you Z Ren?

Claim your profile

Publications (9)25.54 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Phagocyte-derived S100 proteins are endogenous activators of innate immune responses. S100A12 binds to the receptor for advanced glycation end-products, while complexes of S100A8/S100A9 (myeloid-related proteins, MRP8/14; calprotectin) are ligands of toll-like receptor 4. These S100 proteins can be detected in stool. In the present study we analyse the release of S100A12 and MRP8/14 from intestinal tissue. Specimens from patients with Crohn's disease (CD; n = 30), ulcerative colitis (UC; n = 30), irritable bowel syndrome (IBS; n = 30) or without inflammation (n = 30) were obtained during endoscopy. After 24 h culture, S100A12 and MRP8/14 were analysed in supernatants. Endoscopic, histological, laboratory and clinical disease activity measures were documented. We found an increased spontaneous release of S100A12 from tissue in inflammatory bowel disease (IBD). The release of S100A12 into the supernatants was 28-fold enhanced in inflamed tissue when compared to non-inflamed tissue (mean 46.9 vs. 1.7 ng/ml, p < 0.0001). In active CD, release of S100A12 and MRP8/14 was strongly dependent on localization, with little release from sites of active ileal inflammation compared to colonic inflammation. This difference was more pronounced for S100A12 than for MRP8/14. S100A12 and MRP8/14 provoked up-regulation of adhesion molecules and chemokines on human intestinal microvascular endothelial cells (HIMECs) isolated from normal colonic tissue. The direct release of phagocyte-derived S100 proteins from inflamed tissues may reflect secretion from infiltrating neutrophils (S100A12) and also monocytes or epithelial cells (MRP8/14). Via activation of pattern recognition receptors, these proteins promote inflammation in intestinal tissue. The enhanced mucosal release can explain the correlation of fecal markers with disease activity in IBD.
    The Journal of Pathology 10/2008; 216(2):183-92. · 7.59 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Support for a role of Mycobacterium avium subspecies paratuberculosis in Crohn's disease is largely based on epidemiological evidence, as no data on mechanisms linking the presence of M. avium subspecies paratuberculosis with gut damage is available. To determine whether the presence of M. avium subspecies paratuberculosis contributes to the pathogenesis of Crohn's disease by promoting cytokine secretion within gut mucosa. A total of 235 subjects were recruited: 63 with Crohn's disease, 53 with ulcerative colitis, 45 with irritable bowel syndrome and 74 normal controls. M. avium subspecies paratuberculosis status was defined by nested PCR using IS900 sequence. Gut mucosal organ cultures were established to detect cytokine secretion patterns. Significantly higher tumour necrosis factor-alpha concentrations were found in culture supernatants for Crohn's disease compared to ulcerative colitis (p<0.05), irritable bowel syndrome (p<0.01) and controls (p<0.0001). When tumour necrosis factor-alpha levels were correlated with the presence of M. avium subspecies paratuberculosis, significantly greater concentrations were only found in M. avium subspecies paratuberculosis-positive Crohn's disease patients (p<0.05). Tumour necrosis factor-alpha levels in M. avium subspecies paratuberculosis-positive Crohn's disease were significantly higher than in M. avium subspecies paratuberculosis-positive ulcerative colitis (p<0.01), M. avium subspecies paratuberculosis-positive irritable bowel syndrome (p<0.05) and M. avium subspecies paratuberculosis-positive controls (p<0.01) and all M. avium subspecies paratuberculosis-negative specimens. The data link M. avium subspecies paratuberculosis with a pathogenic mechanism in Crohn's disease and is consistent with abnormal macrophage handling of M. avium subspecies paratuberculosis.
    Digestive and Liver Disease 05/2007; 39(5):445-51. · 3.16 Impact Factor
  • Journal of Crohn's and Colitis Supplements. 01/2007; 1(1):45-45.
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Atherosclerosis is an inflammatory response, probably to a range of initiating causes. Chronic infection with Chlamydia pneumoniae (C.pn) has been suggested as one cause, but the nature of the association is controversial, in large part due to lack of an identified mechanism to link infection with the atherosclerotic process in man. This study examined 139 consecutive subjects with stable chest pain, with the aim of correlating the serological status of C.pn infection with the pattern of secretion of cytokines from CD4(+) T lymphocytes. C.pn seropositive subjects secreted significantly more interleukin (IL)-4 than did those who were C.pn seronegative (P = 0.02). No significant difference was noted for secreted interferon (IFN)-gamma. The amount of secreted IL-4, but not of secreted IFN-gamma, correlated positively with the extent of coronary artery disease (P = 0.006). A similar correlation with secreted IL-4 was not identified with Helicobacter pylori infection. These results support the hypothesis that C.pn infection contributes to the inflammatory process responsible for coronary artery atherosclerosis. The method used to detect cytokine secretion involves ligation of CD40L on blood CD4(+) T cells, which may have relevance to tissue events.
    Clinical & Experimental Immunology 12/2006; 146(2):197-202. · 3.41 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The performance of commercial Helicobacter pylori diagnostic kits developed for particular geographic regions has often been found to be of poor diagnostic value when applied to other regions, possibly because of infections being caused by different H. pylori strains in different regions. To evaluate the performance of an IgG2 anti-H. pylori enzyme-linked immunoassay test (Helirad Alert) for detection of H. pylori infection in both Australian and Hong Kong (Chinese) subjects. Serum samples were tested for H. pylori specific IgG2 and IgG antibodies by enzyme-linked immunoassay kits using identical antigen preparation in 168 Australian and 160 Hong Kong (Chinese) subjects diagnosed with dyspepsia. Using a cut-off value determined by analysis of H. pylori-negative Australian samples, the sensitivity, specificity and accuracy of the IgG2 assay were 77.8, 97.4 and 91.1%, respectively, for the Australian samples and 96.3, 83.8 and 90% for Hong Kong samples. For the IgG assay, sensitivity, specificity and accuracy were 87.0, 99.1 and 95.2% for Australian samples and 97.5, 75 and 86.3% for Hong Kong samples respectively. Receiver-operating characteristic analysis showed better discrimination of H. pylori status when the IgG2 assay was applied to Hong Kong samples, while the IgG assay was better in the Australian samples. These data demonstrate that the Helirad Alert enzyme-linked immunoassay could provide a reliable method for screening H. pylori infection in both western and Chinese populations.
    Alimentary Pharmacology & Therapeutics 02/2005; 21(1):83-9. · 4.55 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The etiology and pathophysiology of stomach carcinoma is complex, and the mechanism whereby H. pylori directly or indirectly induces carcinoma remains unclear. In this study, interleukin (IL)-8, IL-4 and interferon (IFN)-gamma were measured in the tissue culture supernatant of gastric organ cultures from subjects with chronic gastritis with or without H. pylori infection, and with or without gastric cancer and gastric dysplasia. Interleukin-8 levels were higher in cancer- and H. pylori-infected gastritis subjects than in H. pylori-negative subjects (12.95 +/- 3.16, 10.48 +/- 1.55 and 4.49 +/- 1.28 ng/mL, respectively). Elevated levels of IFN-gamma were detected in both H. pylori-infected and non-infected subjects with uncomplicated gastritis (72.23 +/- 19.0 and 34.61 +/- 5.30 pg/mL) and in non-infected dysplasia subjects (88 +/- 20.5 pg/mL). Background levels of IL-4 (< or = 9.4 pg/mL) in uncomplicated gastritis subjects and relatively high levels of IL-4 in dysplasia subjects (25.8 +/- 7.3 pg/mL) were detected. In contrast, trace amounts of IFN-gamma (16.01 +/- 0.35 pg/mL) and high levels of IL-4 (42.81 +/- 8.49 pg/mL) in gastric biopsy culture supernatants were found in cancer subjects. Mucosal IL-4 levels (but not IL-8 levels) correlated with infection and mucosal anti-H. pylori immunoglobulin G antibody. The significant differences between gastritis with and without cancer and dysplasia indicated a shift from a Th1 to a Th2 helper cell pattern of cytokine secretion. This study has identified a local mucosal defect in gastric cancer. The near absence of IFN-gamma production from the mucosa at the margins of the tumor may be a critical factor in promoting growth of neoplastic cells.
    Journal of Gastroenterology and Hepatology 02/2001; 16(2):142-8. · 3.33 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Helicobacter pylori infection is the commonest cause of gastritis. Different patterns of immune response to H. pylori infection and characteristics of bacteria are considered to contribute to clinical outcomes. To determine characteristics of the host H. pylori relationship in subjects with non-ulcer dyspepsia and a histological diagnosis of gastritis. Thirty-five subjects with chronic gastritis undergoing endoscopy (mean age 53 years, range 24-82, 14 male and 21 female) were studied, none of whom was on nonsteroidal anti-inflammatory drugs or antibiotics. H. pylori infection was determined by rapid urease test (CLOtest), culture, antibody and RT-PCR for Ure C, Cag A and 26 kDa gene and histology. Cytokine production of mucosal IL-6 and IL-8 were measured by ELISA. Fifteen subjects were positive by CLOtest and/or bacterial culture. In these subjects histology showed numerous helical forms of H. pylori (Group I). Nine subjects were negative by CLOtest, bacterial culture, and mRNA for urease C fragment, but positive by PCR for the 26 kDa protein encoding gene. Histology in these subjects showed the presence of either coccoid forms (four), or scant helical forms (two), or mixed coccoid/helical forms (three) (Group II). Eleven subjects were negative by all methods of detection (Group III). IgG and IgA antibody levels in serum (p<0.05) and gastric tissue culture supernatant (p<0.001) were significantly higher in Group I than those in Group II or III. There were significant differences in the IgG serum and IgA supernatant antibody levels (p<0.01 and p<0.05) when Group II was compared to Group III. Supernatant IL-6 levels were significantly higher in Group I (p<0.01) than those from Groups II and III. IL-8 levels were higher in Group I (p<0.01) and Group II (p<0.05) when compared to Group III. 'H. pylori-negative' gastritis can be associated with a non-urease producing form of H. pylori, with a reduction in both local and systemic antibody levels and mucosal pro-inflammatory cytokines.
    Australian and New Zealand journal of medicine 10/2000; 30(5):578-84.
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Helicobacter pylori elicits a specific humoral and cellular immune response. There is increasing evidence that the type of T-cell response contributes to clinical outcome in H. pylori infection. The host response to H. pylori infection in 34 subjects with chronic gastritis was examined in terms of T-cell proliferation and cytokine production in whole-blood cultures stimulated or unstimulated with H. pylori acid-glycine extract antigens (AGE). The proliferative response in whole-blood cultures was similar for both H. pylori-positive and -negative subjects stimulated with H. pylori AGE. While an increase in interferon-gamma (IFN-gamma) production was observed from both H. pylori-positive and -negative subjects with gastritis, significantly higher levels of IFN-gamma were detected in the former when stimulated with H. pylori AGE. In contrast, interleukin 4 (IL-4) was undetectable regardless of antigen stimulation. However, if an in situ IL-4 antibody capture assay was used, antigen-independent production of IL-4 was detected, but there was no difference between H. pylori-positive and -negative subjects with gastritis. After eradication of H. pylori, antigen-induced production of IL-4 was increased, with no decrease in the levels of secretion of IFN-gamma. IL-4 production was dependent on CD4+ T cells, as addition of anti-CD4 but not anti-CD8 mouse monoclonal antibody or matched IgG isotype to the whole-blood culture inhibited the production of IL-4. The results suggest that a shift toward a balanced Th1-Th2 response due to an increase in antigen-induced IL-4 production from CD4+ T cells follows eradication. We suggest that the downregulation of mucosal inflammation consequent on reduction in antigen levels or removal of downregulation after eradication of H. pylori contributes to this shift in cytokine balance.
    Helicobacter 10/2000; 5(3):135-41. · 3.51 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Controversy exists as to whether the coccoid form of Helicobacter pylori can exist in a viable form. Conversion of helical to coccoid morphology occurs in culture over several days. In this study, the morphology was correlated with parameters of genetic integrity in the reference NCTC 11637 strain over 21 days of culture. The capacity to regrow colonies of helical form was demonstrated from a culture where the coccoid form constituted up to 95% and negligible urease activity could be detected. Urease enzyme activity and its mRNA decreased between day 0 and 10 while 26 kD mRNA and 16S rRNA were expressed unchanged for up to 14 and 21 days of culture, respectively. Expression of mRNA for the Cag A gene behaved in a similar fashion to that of urease. No evidence of DNA fragmentation was detected. These data suggest that a viable form of non-urease producing H. pylori exists after short to intermediate culture and that some if not all of these viable bacteria have coccoid morphology.
    Microbios 02/1999; 97(388):153-63.

Publication Stats

144 Citations
25.54 Total Impact Points

Institutions

  • 2008
    • University of Münster
      Muenster, North Rhine-Westphalia, Germany
    • John Hunter Hospital
      New Lambton, New South Wales, Australia
  • 1999–2006
    • University of Newcastle
      • Discipline of Immunology and Microbiology
      Newcastle, New South Wales, Australia