John N. Gordon

Matrix metalloproteinase-3 production by gut IgG plasma cells in chronic inflammatory bowel disease.

Background: In both ulcerative colitis (UC) and Crohns disease (CD) there is a marked increase in mucosal IgG plasma cells (PC), although their precise role is not well established. In this study we isolated gut PCs from patients with IBD and normal controls and analyzed cytokine production, matrix metalloproteinase (MMP)‐3 and tissue inhibitor of metalloproteinase (TIMP)‐1 production, and PC longevity ex vivo. Methods: Lamina propria mononuclear cells (LPMCs) were isolated from patients with CD (n = 19), UC (n = 27), and normal controls (n = 42). PCs were further selected by immunomagnetic isolation using CD138 microbeads. Cytokine, MMP‐3, and TIMP‐1 expression was investigated by Taqman polymerase chain reaction (PCR), enzyme‐linked immunosorbent assay (ELISA), Western blotting, and confocal microscopy. PC lifespan in vitro was studied by ELISpot analysis. Results: PCs from both controls and IBD patients contained high levels of transcripts for TGF&bgr;, whereas they did not contain significant transcripts for IL‐4, IL‐5, IL‐10, IFN&ggr;, TNF, or IL‐12p40. PCs from patients with CD and UC expressed significantly higher levels of MMP‐3 protein and transcripts than controls (P < 0.0001). The vast majority of MMP‐3‐expressing PCs were IgG+ve. In culture, IgA PCs from both IBD patients and controls persisted for only a few days, but IgG PCs from IBD patients persisted for at least 3 weeks. Conclusions: We have demonstrated that IgG PCs from patients with IBD express large amounts of MMP‐3 and that they appear to be long‐lived. These results identify a new pathway by which IgG PCs may damage the gut.

Immunopathogenesis of Crohn's disease.

This review highlights the huge advances made in the understanding of Crohns disease in the last 15 years. The pathogenic immune response in the gut wall is a highly polarised T helper cell type 1 response, probably directed against antigens of the commensal flora. There is marked over-expression of pro-inflammatory cytokines such as tumor necrosis factor (TNF)-alpha and increased production of matrix degrading enzymes by fibroblasts and macrophages, which are probably responsible for ulceration and fistula formation. Crohns disease runs in families and the susceptibility genes identified so far are associated with innate recognition of microbial products (Nod2) or epithelial barrier function (OCTN cation transporter genes and DLG5). Endogenous healing pathways mediated by transforming growth factor (TGF)-beta1 are inhibited because mucosal inflammatory cells express Smad7, the endogenous intracellular inhibitor of TGF-beta signalling. This makes it unlikely that enteral feeds containing TFG-beta are therapeutic by means of direct anti-inflammatory effects, however TGF-beta may still be involved because it is a well known epithelial motogen and may promote mucosal healing, in synergy with changes in mucosal bacterial populations as a result of the change in the diet.

CC-10004 but not thalidomide or lenalidomide inhibits lamina propria mononuclear cell TNF-α and MMP-3 production in patients with inflammatory bowel disease

BACKGROUND Thalidomide, one of whose activities is to inhibit Tumour Necrosis Factor (TNF)-α production, has been reported to be an effective treatment for refractory inflammatory bowel disease (IBD). TNF-α driven production of matrix metalloproteinase (MMP)-3 by gut lamina propria mononuclear cells (LPMCs) is a major pathway of tissue injury in IBD; however the effect of thalidomide and newer more potent immunomodulatory derivatives on this pathway has not been studied. AIM To investigate the effect of thalidomide, CC-4047 (pomalidomide), CC-5013 (lenalidomide), and CC-10004 (apremilast) on gut LPMC TNFα and MMP-3 production in patients with IBD. METHODS Gut LPMCs and myofibroblasts were isolated from patients with IBD, and cultured with thalidomide, CC-4047, CC-5013, and CC-10004. MMP-3 and TIMP-1 levels were determined by western blotting and real-time PCR, and TNF-α levels by ELISA. RESULTS CC-10004 significantly reduced both TNF-α production and MMP-3 production by cultured LPMCs. Thalidomide and CC-4047 and CC-5013 had no significant effect on the production of TNF-α or MMP-3 by LPMCs. CONCLUSION These results provides a mechanistic rationale for both the failure of lenalidomide (CC-5013) in a recent randomised controlled trial in Crohns disease, and for the evaluation of CC-10004 as a novel oral therapy in the treatment of CD and UC.

Stromelysin-1 and macrophage metalloelastase expression in the intestinal mucosa of Crohn's disease patients treated with infliximab.

Background and aims The mechanism by which anti-tumor necrosis factor (TNF)-&agr; therapy promotes rapid closure of fistulas and mucosal wound healing in Crohns disease (CD) remains unclear. An ex-vivo model of gut T-cell mediated injury indicated that TNF-&agr; blockade prevents tissue damage concomitant with matrix metalloproteinase (MMP) inhibition. We, therefore, hypothesized that the chimeric anti-TNF-&agr; antibody infliximab facilitates wound healing in CD by downregulating tissue degrading MMPs. We focused on MMP-3 (stromelysin-1) and MMP-12 (macrophage metalloelastase) as these two enzymes have been linked to connective tissue destruction in CD. Methods Endoscopic biopsies were taken from 10 CD patients immediately before and after 10 weeks of treatment with infliximab. Before treatment, biopsies were taken from macroscopically inflamed areas, and after treatment were collected from the same locations as before treatment. The degree of mucosal damage was assessed by using a histological scoring system. MMP transcripts were detected by in-situ hybridization on paraffin sections. MMP proteins were determined by immunoblotting on mucosal homogenates. Results Six out of 10 patients had a clinical response to infliximab. MMP-3 and MMP-12 transcripts and proteins, which were highly expressed in CD inflamed mucosa, decreased after treatment in those patients who responded to infliximab. MMP-3 and MMP-12 downregulation was accompanied by a concomitant improvement of the histologic score. No change in MMP expression was found in nonresponders. Conclusion The downregulation of tissue degrading MMPs in CD mucosa may explain the wound repair capacity of infliximab in healing fistulas and ulcers.

Lambda Light Chain Revision in the Human Intestinal IgA Response

Revision of Ab L chains by secondary rearrangement in mature B cells has the potential to change the specific target of the immune response. In this study, we show for the first time that L chain revision is normal and widespread in the largest Ab producing population in man: intestinal IgA plasma cells (PC). Biases in the productive and non-productive repertoire of λ L chains, identification of the circular products of rearrangement that have the characteristic biases of revision, and identification of RAG genes and protein all reflect revision during normal intestinal IgA PC development. We saw no evidence of IgH revision, probably due to inappropriately orientated recombination signal sequences, and little evidence of κ-chain revision, probably due to locus inactivation by the κ-deleting element. We propose that the λ L chain locus is available and a principal modifier and diversifier of Ab specificity in intestinal IgA PCs.

Osteopontin: a new addition to the constellation of cytokines which drive T helper cell type 1 responses in Crohn’s disease

Osteopontin, a cytokine which promotes Th1 immune responses, is overexpressed in the gut of patients with Crohn’s disease or ulcerative colitis. The main cellular source of this cytokine appears to be gut plasma cells. Crohn’s disease appears to be caused by an excessive CD4+ T helper cell type I response directed against undefined antigens of the commensal bacterial flora.1 T cells from affected areas of Crohn’s disease mucosa produce enhanced amounts of interferon γ (IFN-γ) and tumour necrosis factor α. Other markers of Th1 cells, such as expression of the transcription factor T-bet, the high affinity β2 chain of the interleukin 12 (IL-12) receptor, and activated STAT4, all indicate that the mucosal environment in Crohn’s disease favours Th1 polarisation.1 It is important to emphasise that CD4 T cells in normal bowel are also Th1 skewed and express T-bet, so that the differences seen in Crohn’s disease are quantitative rather than qualitative.2 Normal mucosal T cells are however susceptible to apoptosis, whereas this is not the case in Crohn’s disease,3 suggesting that it is the persistence and accumulation of Th1 cells which drives tissue injury. Factors which commit virgin T cells to the Th1 or Th2 pathway are still under investigation. T-bet appears to be of primary importance.4 It is induced by IFN-γ itself and is capable of promoting IFN-γ production, not only in Th1 cells, but also in Th2 cells. T-bet also increases expression of the IL-12Rβ2 chain. Macrophage and dendritic cell derived IL-12 is crucial in Th1 immune responses.5 The …

P618 The relationship between disease severity, quality of life and health care resource utilization among United Kingdom patients with ulcerative colitis

Conclusions: Urinary metabolic profiling has shown distinct differences in South Asian IBD patients and controls, as has been previously shown in Caucasian studies. However, no difference in urinary hippurate was found between South Asian Crohn’s disease and UC patients, contrary to findings in Caucasians. Nor could these groups be distinguished using multivariate analysis. Some changes in the discriminatory metabolites are similar to those in Caucasian IBD but some are different suggesting an effect of ethnicity on the metabolic profile, which will be further investigated.

Disease status, patient quality of life and healthcare resource use for ulcerative colitis in the UK: an observational study

Background Ulcerative colitis is a lifelong, chronic, relapsing-remitting disease. Objective To assess the relationship between ulcerative colitis disease status and patient quality of life, and to determine the impact of ulcerative colitis on healthcare costs and work productivity, in the UK. Methods Clinicians assessed 173 adult patients’ current disease status at a single study visit using the partial Mayo (pMayo) instrument. Patients completed the Euro Quality of Life 5-dimension, 5-level (EQ-5D-5L) questionnaire, the Work Productivity and Activity Impairment (WPAI) questionnaire. Healthcare resource use was determined from questionnaires and from patients’ medical charts. Results Patients in remission had a significantly higher EQ-5D-5L scores (mean (SD) 0.86 (0.15)) than patients with active disease (0.71 (0.20); p<0.001). Patients with mild disease had significantly higher mean (SD) EQ-5D-5L scores than patients with moderate/severe disease: 0.77 (0.11) and 0.66 (0.24), respectively (p<0.001). The mean percent productivity impairment was greater for patients with active disease than for patients in remission on all items of the WPAI questionnaire: 24.6% vs 1.8% for work time missed, 34.1% vs 12.9% for impairment while working, 40.8% vs 14.4% for overall work impairment and 42.7% vs 13.0% for activity impairment (p<0.001 for all comparisons). The mean (SD) total cost of healthcare for ulcerative colitis in the prior 3 months was £1211 (1588). Conclusions When compared with patients in remission, patients with active ulcerative colitis have significantly worse quality of life and significantly more work impairment. The healthcare costs of ulcerative colitis are considerable.