Epithelioid granulomas, pattern recognition receptors, and phenotypes of Crohn's disease

INTRODUCTION

Crohn's disease is a chronic inflammatory disorder of the gut. It is assumed that a defective interaction between the bacterial flora of the gut and the innate immune system plays a key role in the pathogenesis of the disease. This may lead to specific histological lesions. The epithelioid granuloma is particularly interesting in this regard as it is also observed in several bacterial infections of the gut.

AIMS AND METHODS

We hypothesised that genetic or environmental factors with a known influence on inflammation or immunity would lead to an increased prevalence of granulomas. Therefore, surgical specimens from 161 patients were evaluated for the presence of granulomas. Patients were genotyped for the three single nucleotide polymorphisms in caspase recruitment domain 15 (CARD15)/NOD2 associated with CD and for Asp299Gly in Toll-like receptor 4 (TLR4).

RESULTS

The overall prevalence of granulomas was 68.9%. We did not find a significant correlation between granulomas and TLR4 or CARD15 variants. The frequency of granulomas increased with more distal disease (63% small bowel, 72% right colon, 88% left colon, 90% rectum; p=0.01). Granulomas were more frequent in younger patients (odds ratio 0.95 (95% confidence interval 0.92-0.98) p=0.007).

CONCLUSION

In this study of 161 well documented CD patients, we found no significant association between CARD15 and TLR4 variants and granulomas. This finding seems to refute our initial hypothesis. However, it may be that additional factors are needed for granuloma development. Granulomas may develop only when specific bacterial components are present. Therefore, future research on granuloma pathogenesis should be orientated towards detection and identification of bacterial components in these lesions.

Frequency and significance of granulomas in a cohort of incident cases of Crohn's disease

BACKGROUND AND AIMS

Epithelioid granulomas is one of the best histological criterion for distinguishing Crohn's disease (CD) from other inflammatory bowel diseases. Few data are available on the time of occurrence of epithelioid granulomas, and the value of epithelioid granulomas in predicting outcome has been determined only in cohorts of prevalent CD cases. Our objective was to evaluate epithelioid granuloma occurrence in incident CD cases and to examine the associations between epithelioid granulomas and outcome.

PATIENTS AND METHODS

We reviewed the histological reports of endoscopic and surgical specimens in a cohort of 188 consecutive incident CD cases seen in 1994 and 1995, and recorded the occurrence of epithelioid granulomas, isolated giant cells, and microgranulomas. Kaplan-Meier curves were plotted for time from CD diagnosis to immunosuppressive treatment or surgery, and associations between epithelioid granulomas and outcome were evaluated in a multivariate analysis. Follow up was at least five years.

RESULTS

Granulomas were found in 69 (37%) patients, including 46 (25%) at presentation. Median time from CD diagnosis to epithelioid granuloma detection was 0.16 (0-63) months overall, and 9.59 (0.1-63) months in 23 patients who became epithelioid granuloma positive during follow up. Isolated giant cells were found in 6% of patients and microgranulomas in 12%. Epithelioid granuloma detection increased with the number of endoscopic sampling procedures; sampling site had no influence. By multivariate analysis, epithelioid granulomas were associated with surgical resection but not immunosuppressive therapy.

CONCLUSIONS

Epithelioid granulomas may separate CD into two pathological subsets and may indicate aggressive disease.

Impact of the increasing use of immunosuppressants in Crohn's disease on the need for intestinal surgery

BACKGROUND/AIM

Immunosuppressants are now used much earlier in the course of Crohn's disease; however their effect on the natural history of the disease, especially on the need for surgery, is not known. The aim of this study was to assess the evolution of the need for surgery in Crohn's disease during the last 25 years.

PATIENTS AND METHODS

The medical charts of 2573 patients were reviewed retrospectively. The use of immunosuppressants (azathioprine or methotrexate), the need for intestinal resection, and the occurrence of intestinal complications were assessed using Kaplan-Meier analysis in five consecutive cohorts of patients defined by the date of diagnosis of Crohn's disease (1978-82; 1983-87; 1988-92; 1993-97; 1998-2002).

RESULTS

In 565 patients seen in the authors' unit within the first three months after diagnosis, characteristics of Crohn's disease at diagnosis did not differ from one cohort to another. The five year cumulative probability to receive immunosuppressants increased from 0 in the 1978-82 cohort to 0.13, 0.25, 0.25, and 0.56 in the 1983-87, 1988-92, 1993-97, and 1998-2002 cohorts, respectively (p<0.001). Concomitantly, the cumulative risk of intestinal resection remained unchanged (from 0.35 to 0.34 at five years; p=0.81). The cumulative risk of developing a stricturing or a penetrating intestinal complication remained also unchanged. Similar results were obtained in the 2008 patients seen during the same period who were referred to us more than three months after diagnosis.

CONCLUSION

Although immunosuppressants have been used more frequently over the last 25 years, there was no significant decrease of the need for surgery, or of intestinal complications of Crohn's disease.

Trichuris suis therapy in Crohn's disease

BACKGROUND

Crohn's disease is common in highly industrialised Western countries where helminths are rare and uncommon in less developed areas of the world where most people carry worms. Helminths diminish immune responsiveness in naturally colonised humans and reduce inflammation in experimental colitis. Thus exposure to helminths may help prevent or even ameliorate Crohn's disease.

AIMS

The aim of the study was to determine the safety and possible efficacy of the intestinal helminth Trichuris suis in the treatment of patients with active Crohn's disease.

PATIENTS

Twenty nine patients with active Crohn's disease, defined by a Crohn's disease activity index (CDAI) > or =220 were enrolled in this open label study.

METHODS

All patients ingested 2500 live T suis ova every three weeks for 24 weeks, and disease activity was monitored by CDAI. Remission was defined as a decrease in CDAI to less than 150 while a response was defined as a decrease in CDAI of greater than 100.

RESULTS

At week 24, 23 patients (79.3%) responded (decrease in CDAI >100 points or CDAI <150) and 21/29 (72.4%) remitted (CDAI <150). Mean CDAI of responders decreased 177.1 points below baseline. Analysis at week 12 yielded similar results. There were no adverse events.

CONCLUSIONS

This new therapy may offer a unique, safe, and efficacious alternative for Crohn's disease management. These findings also support the premise that natural exposure to helminths such as T suis affords protection from immunological diseases like Crohn's disease.

Indeterminate colitis

Indeterminate colitis (IC) originally referred to those 10-15% of cases of inflammatory bowel disease (IBD) in which there was difficulty distinguishing between ulcerative colitis (UC) and Crohn's disease (CD) in the colectomy specimen. However, IC is increasingly used when a definitive diagnosis of UC or CD cannot be made at colonoscopy, in colonic biopsies or at colectomy. The diagnostic difficulties may explain the variably reported prevalence of IC. Clinically, most patients with IC evolve to a definite diagnosis of UC or CD on follow up. The role of ancillary tests in the distinction of UC from CD is reviewed. The low sensitivity of serological markers limits their usefulness. Other tests include upper endoscopy and magnetic resonance imaging. The definition of IC may not be a purely histological one derived from resected specimens, but rather a clinicopathological one. This review offers some personal observations and viewpoints, and proposes an approach to some of the relatively more esoteric combinations of findings.

Increased epithelial uptake of protein antigens in the ileum of Crohn's disease mediated by tumour necrosis factor alpha

BACKGROUND AND AIMS

The exact nature of the epithelial barrier defect in Crohn's disease remains to be elucidated. Previously we showed increased permeability to proteins in ileal Crohn's disease. Our aims were to study if this barrier defect (a) involves endocytotic uptake of antigens and (b) is related to low grade inflammation not detectable by histology.

METHODS

Macroscopically normal segments of distal ileum of Crohn's disease patients (n = 10) were subgrouped into non-inflamed (histologically unaffected) and slightly inflamed tissues and studied in Ussing chambers, with normal ileal specimens from colon cancer patients (n = 9) as controls. Endocytotic uptake into enterocytes of the protein antigen horseradish peroxidase was assessed by measuring the area of horseradish peroxidase containing endosomes in electron photomicrographs. Mucosal tumour necrosis factor alpha (TNF-alpha) mRNA was quantified using real time polymerase chain reaction. For comparison, the effects of low doses of TNF-alpha on endosomal uptake of horseradish peroxidase were studied in cultured T84 cells grown on filter supports.

RESULTS

The area of horseradish peroxidase containing endosomes was increased (p<0.001) in enterocytes of non-inflamed ileum of Crohn's disease (2.8 (0.7) mum(2)/300 mum(2)) compared with control ileum (0.6 (0.06)). In non-inflamed mucosa, a significant association between endosomal uptake and mucosal expression of TNF-alpha mRNA (p = 0.03) was found. Low concentrations of TNF-alpha (0.25-1.0 ng/ml) enhanced the endosomal uptake of horseradish peroxidase in polarised T84 cells, without affecting transepithelial electrical resistance.

CONCLUSIONS

Our findings suggest increased endosomal uptake of antigens in ileal Crohn's disease that may be mediated by TNF-alpha. These data highlight the transcellular route of antigen uptake in barrier dysfunction and implicate the interaction between epithelial cells and the innate immune system in the development of mucosal inflammation.

NOD2 (CARD15) mutations in Crohn's disease are associated with diminished mucosal alpha-defensin expression

BACKGROUND

Mutations in NOD2, a putative intracellular receptor for bacterial peptidoglycans, are associated with a subset of Crohn's disease but the molecular mechanism linking this protein with the disease pathogenesis remains unclear. Human alpha defensins (HD-5 and HD-6) are antibiotic effector molecules predominantly expressed in Paneth cells of the ileum. Paneth cells also express NOD2. To address the hypothesis that the function of NOD2 may affect expression of Paneth cell defensins, we compared their expression levels with respect to NOD2 mutations in Crohn's disease.

METHODS

Forty five Crohn's disease patients (24 with NOD2 mutations, 21 with wild-type NOD2) and 12 controls were studied. Real time reverse transcription-polymerase chain reaction was performed with mucosal mRNA for HD-5, HD-6, lysozyme, secretory phospholipase A2 (sPLA2), tumour necrosis factor alpha, interleukin 8, and human hypoxanthine phosphoribosyltransferase (housekeeping gene). Immunohistochemistry with anti-HD-5 and histological Paneth cell staining were performed in 10 patients with NOD2 mutations or wild-type genotypes.

RESULTS

Ileal expression of HD-5 and HD-6, but not sPLA2 or lysozyme, were diminished in affected ileum, and the decrease was significantly more pronounced in patients with NOD2 mutations. In the colon, HD-5, HD-6, and sPLA2 were increased during inflammation in wild-type but not in NOD2 mutated patients. In both the colon and ileum, proinflammatory cytokines and lysozyme were unaffected by NOD2 status. Immunohistochemistry identified Paneth cells as the sole source of HD-5.

CONCLUSION

As alpha defensins are important in the mucosal antibacterial barrier, their diminished expression may explain, in part, the bacterial induced mucosal inflammation and ileal involvement of Crohn's disease, especially in the case of NOD2 mutations.

Divergent cell cycle kinetics underlie the distinct functional capacity of mucosal T cells in Crohn's disease and ulcerative colitis

BACKGROUND

Different abnormalities of T cell effector function distinguish Crohn's disease (CD) from ulcerative colitis (UC). Because cell cycling determines effector function, pathogenic events in CD and UC may depend on cell cycle changes unique to each condition.

METHODS

Cell cycle kinetics, cycle regulatory molecule expression, apoptosis, caspase and telomerase activity, and cellular expansion were evaluated in CD2 and CD3 activated control, CD, and UC lamina propria T cells.

RESULTS

Compared with normal cells, CD T cells cycle faster, express increased phosphorylated Rb and decreased phosphorylated p53 levels, display less caspase activity but more telomerase activity, die less, and undergo vigorous cellular expansion. In contrast, UC T cells cycle slower, express normal levels of phosphorylated Rb and p53, display more caspase activity but have no telomerase activity, die more, and have a limited capacity to expand.

CONCLUSIONS

T cell cycle abnormalities in CD indicate a state of hyperreactivity compatible with loss of tolerance, but a hyporeactive state compatible with anergy in UC. Thus distinct and divergent T cell cycle characteristics underlie the pathogenesis of the two main forms of inflammatory bowel disease.

Induction of T lymphocyte apoptosis by sulphasalazine in patients with Crohn's disease

BACKGROUND

Lamina propria T lymphocytes (LPL) of the intestinal mucosa are chronically activated in Crohn's disease (CD). Defective apoptosis of activated LPL was proposed as a key pathogenic mechanism. In fact, increased expression of antiapoptotic molecules was observed in CD LPL. In the present work, we aimed to analyse the effects and underlying molecular mechanisms of 5-amino salicylic acid (5-ASA) and derivatives on apoptosis of LPL and peripheral blood lymphocytes (PBL) in patients with CD compared with ulcerative colitis (UC) and in non-inflammatory controls.

METHODS

PBL and LPL were isolated by Ficoll-Hypopaque gradient centrifugation and the EGTA-collagenase method, respectively. PBL/LPL were stimulated with FasL, 5-ASA, sulphapyridine, and sulphasalazine for 24/48 hours and apoptosis was quantified by flow cytometry (annexin V- propidium iodide method) and immunofluorescence. The molecular mechanisms of drug induced apoptosis were analysed in wild-type and FADD-/- Jurkat T cells using western blots and caspase assays.

RESULTS

While PBL displayed a normal apoptosis pattern after Fas stimulation in patients with active CD, LPL from inflammatory areas were highly resistant. Comparable resistance to apoptosis was observed in LPL of UC patients. In contrast with 5-ASA, which did not induce apoptosis in lymphocytes, sulphasalazine proved to be a potent proapoptotic agent. Sulphasalazine induced T lymphocyte apoptosis was independent of the Fas pathway but associated with marked downregulation of antiapoptotic bcl-xl and bcl2, activation of the mitochondrial apoptosis signalling pathway, and subsequent activation of caspase-9 and caspase-3.

CONCLUSION

The beneficial effect of sulphasalazine in treating inflammatory bowel disease is at least in part attributable to its proapoptotic effects on LPL which allows potent downregulation of lymphocyte activation.

Oral contrast enhanced bowel ultrasonography in the assessment of small intestine Crohn's disease. A prospective comparison with conventional ultrasound, x ray studies, and ileocolonoscopy

BACKGROUND/ AIM: Although ultrasound (US) has proved to be useful in intestinal diseases, barium enteroclysis (BE) remains the gold standard technique for assessing patients with small bowel Crohn's disease (CD). The ingestion of anechoic non-absorbable solutions has been recently proposed in order to distend intestinal loops and improve small bowel visualisation. The authors' aim was to evaluate the accuracy of oral contrast US in finding CD lesions, assessing their extent within the bowel, and detecting luminal complications, compared with BE and ileocolonoscopy.

METHODS

102 consecutive patients with proven CD, having undergone complete x ray and endoscopic evaluation, were enrolled in the study. Each US examination, before and after the ingestion of a polyethylene glycol (PEG) solution (500-800 ml), was performed independently by two sonographers unaware of the results of other diagnostic procedures. The accuracy of conventional and contrast enhanced US in detecting CD lesions and luminal complications, as well as the extent of bowel involvement, were determined. Interobserver agreement between sonographers with both US techniques was also estimated.

RESULTS

After oral contrast, satisfactory distension of the intestinal lumen was obtained in all patients, with a mean time to reach the terminal ileum of 31.4 (SD 10.9) minutes. Overall sensitivity of conventional and oral contrast US in detecting CD lesions were 91.4% and 96.1%, respectively. The correlation coefficient between US and x ray extent of ileal disease was r1 = 0.83 (p<0.001) before and r2 = 0.94 (p<0.001) after PEG ingestion; r1 versus r2 p<0.01. Sensitivity in detecting strictures was 74% for conventional US and 89% for contrast US. Overall interobserver agreement for bowel wall thickness and disease location within the small bowel was already good before but significantly improved after PEG ingestion.

CONCLUSIONS

Oral contrast bowel US is comparable with BE in defining anatomic location and extension of CD and superior to conventional US in detecting luminal complications, as well as reducing interobserver variability between sonographers. It may be therefore regarded as the first imaging procedure in the diagnostic work up and follow up of small intestine CD.

CDP571, a humanised monoclonal antibody to tumour necrosis factor alpha, for moderate to severe Crohn's disease: a randomised, double blind, placebo controlled trial

BACKGROUND

Targeting tumour necrosis factor alpha (TNF-alpha) has demonstrated efficacy in Crohn's disease.

AIM

To evaluate CDP571, a humanised antibody to TNF-alpha, for treating active Crohn's disease.

PATIENTS

A total of 396 patients with moderate to severe Crohn's disease.

METHODS

In a 28 week, randomised, double blind, placebo controlled trial, patients received intravenous CDP571 (10 mg/kg) or placebo every eight weeks to week 24. The primary outcome measure was clinical response (a decrease in the Crohn's disease activity index (CDAI) to > or =100 points or remission (CDAI score < or =150 points)) at week 28. A secondary outcome measure was clinical response (using the same definition) at week 2.

RESULTS

Clinical response occurred at week 28 in 80/263 (30.4%) CDP571 patients and 31/132 (23.5%) placebo patients (p = 0.102). Clinical response at week 2 occurred in 90/263 (34.2%) CDP571 patients and 28/132 (21.2%) placebo patients (p = 0.011). Post hoc exploratory subgroup analysis of 159 patients with baseline C reactive protein (CRP) > or =10 mg/l demonstrated significant differences between CDP571 and placebo in clinical response rates at weeks 2 (CDP571, 50/101 (49.5%); placebo, 9/58 (15.5%); p<0.001) and 28 (CDP571, 29/101 (28.7%); placebo, 7/58 (12.1%); p = 0.018). Adverse events occurred at similar frequencies in both treatment groups.

CONCLUSIONS

CDP571 is modestly effective for short but not long term treatment of unselected patients with moderate to severe Crohn's disease. The clinical relevance of this short term effect is unclear. Post hoc analysis suggests both short and long term efficacy of CDP571 in patients with elevated baseline CRP (> or =10 mg/l). CDP571 is well tolerated.

Cost of illness of inflammatory bowel disease in the UK: a single centre retrospective study

BACKGROUND AND AIMS

The potentially high costs of care associated with inflammatory bowel disease (IBD) are recognised but we have little knowledge of the scale, profile, or determinants of these costs in the UK. This study aimed to describe costs of illness for a group of IBD patients and determine factors associated with increased healthcare costs.

SETTING

A university hospital serving a target population of approximately 330 000.

PATIENTS AND METHODS

A six month cohort of IBD patients receiving any form of secondary care was identified, comprising 307 cases of ulcerative (or indeterminate) colitis and 172 cases of Crohn's disease. Demographic and clinical data were abstracted from clinical records and individual resource use was itemised for all attributable costs (including extraintestinal manifestations). Item costs were derived from national and local sources. Cost data were expressed as mean six month costs per patient (with 95% confidence interval (CI)) obtained using non-parametric bootstrapping. Determinants of cost were analysed using generalised linear regression modelling. A postal survey of patients was undertaken to examine indirect costs, out of pocket expenses, and primary care visits.

RESULTS

Inpatient services (medical and/or surgical) were required by 67 patients (14%) but accounted for 49% of total secondary care costs. Drug costs accounted for less than a quarter of total costs. Individual patient costs ranged from 73 to 33,254 UK pounds per six months. Mean (95% CI) six month costs per patient were 1256 UK pounds ( 988 pounds, 1721 pounds) for colitis and 1652 UK pounds (1221 pounds, 2239 pounds) for Crohn's disease. Hospitalisation, disease severity grade, and disease extent correlated positively with cost of illness but costs were independent of age or sex. Compared with quiescent cases of IBD, disease relapse was associated with a 2-3-fold increase in costs for non-hospitalised cases and a 20-fold increase in costs for hospitalised cases. Survey data suggested average six month costs were < 30 UK pounds per patient for primary care visits (both diseases) and median loss of earnings were 239 UK pounds for colitis and 299 UK pounds for Crohn's disease.

CONCLUSIONS

This study represents the first detailed characterisation of the scale and determinants of costs of illness for IBD in a British hospital. Hospitalisation affected a minority of sufferers but accounted for half of the total direct costs falling on the healthcare system.

T-bet upregulation and subsequent interleukin 12 stimulation are essential for induction of Th1 mediated immunopathology in Crohn's disease

BACKGROUND AND AIMS

Many lines of evidence suggest that T helper cell type 1 (Th1) immune responses predominate in Crohn's disease (CD). Recently, a novel transcription factor T-box expressed in T cells (T-bet) has been reported as the master regulator of Th1 development. This study was designed to investigate the role of T-bet and proinflammatory cytokines in Th1 mediated immunopathology in CD.

MATERIALS

CD4+ lamina propria mononuclear cells (LPMCs) were isolated from surgically resected specimens (CD, n = 10; ulcerative colitis (UC), n = 10; normal controls (NL), n = 5).

METHODS

(1) T-bet expression of CD4+ LPMCs was examined by quantitative real time polymerase chain reaction and western blotting. (2) T-bet expression of LPMCs stimulated by interleukin (IL)-12/IL-18 was analysed by western blotting. (3) Interferon gamma (IFN-gamma) production and T-bet expression of CD4+ peripheral blood mononuclear cells (PBMCs) were examined with or without stimulation by anti-CD3/CD28 monoclonal antibodies and/or IL-12.

RESULTS

(1) T-bet expression of CD4+ LPMCs was increased in CD compared with UC and NL. (2) Synergistically, augmentation of IFN-gamma production by IL-12/IL-18 was independent of T-bet expression in LPMCs. (3) T-bet was induced by T cell receptor stimulation in CD4+ PBMCs. T-bet induction correlated with IFN-gamma production and with augmentation of surface expressed IL-12 receptor beta2.

CONCLUSIONS

T-bet induction by antigenic stimulation and subsequent stimulation by macrophage derived IL-12/IL-18 are important for establishing Th1 mediated immunopathology in CD.

Downregulation of epithelial apoptosis and barrier repair in active Crohn's disease by tumour necrosis factor alpha antibody treatment

BACKGROUND AND AIMS

Barrier dysfunction is an important feature contributing to inflammation and diarrhoea in Crohn's disease (CD). Recently, tumour necrosis factor alpha (TNF-alpha) antibodies were recognised as effective in steroid refractory CD. The aim of this study was to characterise the effects of this therapy on the epithelial barrier.

PATIENTS AND METHODS

Forceps biopsies were obtained from the sigmoid colon before and 14 days after TNF-alpha antibody therapy in 11 patients treated for chronic active CD (Crohn's disease activity index >150). Epithelial apoptoses were measured after terminal deoxynucleotidyl transferase mediated deoxyuridine triphosphate nick end labelling (TUNEL) and 4',6-diamidino-2-phenylindole staining. Epithelial resistance was determined by alternating current impedance analysis in miniaturised Ussing chambers. Occludin, claudin 1, and claudin 4 expression was quantified in immunoblots.

RESULTS

The epithelial apoptotic ratio was 2.1 (0.2)% in controls and increased to 5.3 (1.0)% in CD. TNF-alpha antibody therapy decreased the apoptotic ratio to 2.9 (1.0)% (normalised in 10 of 11 patients). In parallel, epithelial resistance was lower in CD than in controls (24 (3) v 42 (3) Omegaxcm(2)) and improved to 34 (3) Omegaxcm(2) after therapy. Occludin, claudin 1, and claudin 4 were not affected by TNF-alpha antibody therapy. In support of a functional role of epithelial apoptoses in CD, a similar decrease in resistance of -40% was observed when the apoptotic rate was selectively upregulated from 2.6% to 5.4% with camptothecin in HT-29/B6 cells.

CONCLUSIONS

Epithelial apoptoses were upregulated in the colon in CD and restored to normal in 10 of 11 patients by TNF-alpha antibody therapy. This is the structural correlate of epithelial barrier dysfunction measured as epithelial resistance while expression of tight junction proteins did not contribute to this therapeutic effect.

Chronic hepatitis B reactivation following infliximab therapy in Crohn's disease patients: need for primary prophylaxis

BACKGROUND

There is little information about the effect of infliximab on the clinical course of liver disease in Crohn's disease patients with concomitant hepatitis B virus (HBV) infection. Theoretically, immunosuppression induced by infliximab will facilitate viral replication which could be followed by a flare or exacerbation of disease when therapy is discontinued. There are no specific recommendations on surveillance and treatment of HBV before infliximab infusion. Two cases of severe hepatic failure related to infliximab infusions have been described in patients with rheumatic diseases.

PATIENTS AND METHODS

Hepatitis markers (C and B) and liver function tests were prospectively determined to 80 Crohn's disease patients requiring infliximab infusion in three hospitals in Spain.

RESULTS

Three Crohn's disease patients with chronic HBV infection were identified. Two of the three patients with chronic HBV infection suffered severe reactivation of chronic hepatitis B after withdrawal of infliximab therapy and one died. A third patient, who was treated with lamivudine at the time of infliximab therapy, had no clinical or biochemical worsening of liver disease during or after therapy. From the remaining 80 patients, six received the hepatitis B vaccine. Three patients had antibodies to both hepatitis B surface antigen (anti-HBs) and hepatitis B core protein (anti-HBc) with normal aminotransferase levels, and one patient had positive anti-hepatitis C virus (HCV) antibodies, negative HCV RNA, and normal aminotransferase levels. Except for the patients with chronic HBV infection, no significant changes in hepatic function were detected.

CONCLUSIONS

Patients with Crohn's disease who are candidates for infliximab therapy should be tested for hepatitis B serological markers before treatment and considered for prophylaxis of reactivation using antiviral therapy if positive.

Morphological characterisation of Crohn's disease fistulae

BACKGROUND

Fistulae are a common complication in up to 35% of all patients with Crohn's disease. Their therapy is difficult and frequently unsatisfactory. To date, no histological comparison of Crohn's disease fistulae with non-inflammatory bowel disease fistulae has been performed. In addition, Crohn's disease fistulae have not been well characterised morphologically.

METHODS

Eighty four fistulae from Crohn's disease patients were compared with 13 fistulae from controls. Haematoxylin-eosin staining, electron microscopy, and immunohistochemistry for panCytokeratin (epithelial cells), CD20 (B cells), CD45R0 (T cells), and CD68 (macrophages) were performed according to standard techniques. In addition, histopathological findings were compared with clinical and laboratory data.

RESULTS

In 31.0% of controls and 27.4% of Crohn's disease specimens, fistulae had a lining of flattened intestinal epithelium without goblet cells or, in the case of cutaneous/perianal disease, narrow squamous epithelium. Non-epithelialised fistulae were covered by a thin layer of (myo)fibroblasts, focally forming a new basement membrane, as demonstrated by electron microscopy. All fistulae were surrounded by granulation tissue. Crohn's disease fistulae presented with central infiltration by CD45R0+ T cells, followed by a small band of CD68+ macrophages and dense accumulation of CD20+ B cells. In contrast, in controls, there was dense infiltration by CD68+ macrophages with only few CD20+ B cells and CD45R0+ T lymphocytes.

CONCLUSIONS

Fistulae in Crohn's disease differ markedly from non-Crohn's disease fistulae with regard to their cellular composition. The presence of an epithelial lining in a subgroup of fistulae may be important for the therapeutic approach and healing process.

Divergent patterns of total and cancer mortality in ulcerative colitis and Crohn's disease patients: the Florence IBD study 1978-2001

BACKGROUND AND AIMS

Two divergent patterns of mortality for smoking related diseases in ulcerative colitis and Crohn's disease patients were suggested in a previous population based study in Florence, Italy. Long term follow up (median 15 years) was completed to re-evaluate mortality in this Mediterranean cohort.

PATIENTS AND METHODS

Overall, 920 patients with inflammatory bowel disease were followed until December 2001 or death, with seven patients (0.8%) lost to follow up. A total of 14 040 person years were available for analysis; 118 deaths were observed (81/689 in ulcerative colitis and 37/231 in Crohn's disease). Expected deaths were estimated using age, sex, and calendar specific national and local mortality rates; standardised mortality ratios (SMR) and 95% confidence interval (CI) were calculated.

RESULTS

Among Crohn's disease patients, mortality was strongly increased for gastrointestinal diseases (SMR 4.49 (95% CI 1.80-9.25)), all cancers (SMR 2.10 (95% CI 1.22-3.36)), and lung cancer (SMR 4.00 (95% CI 1.60-8.24)), leading to a significant 50% excess total mortality. Ulcerative colitis patients showed a significantly reduced total mortality because of lower cardiovascular (SMR 0.67 (95% CI 0.45-0.95)) and lung cancer (SMR 0.32 (95% CI 0.07-0.95)) mortality. No significant excess for colorectal cancer mortality was evident in this extended follow up.

CONCLUSIONS

These clearly divergent patterns of mortality correlate with documented differences in smoking habits between Crohn's disease and ulcerative colitis patients. Family doctors and gastroenterologists should consider stopping cigarette smoking a specific priority for Crohn's disease patients; the latter should be offered free participation in structured programmes for smoking cessation, with the aim of reducing smoking related excess mortality. Overall, no evidence of an increased mortality for large bowel cancer emerged in this series.

Measurement of vitamin D levels in inflammatory bowel disease patients reveals a subset of Crohn's disease patients with elevated 1,25-dihydroxyvitamin D and low bone mineral density

OBJECTIVES

Many patients with Crohn's disease (CD) have low bone mineral density (BMD) that may not be solely attributable to glucocorticoid use. We hypothesised that low BMD in patients with CD is associated with elevated circulating levels of the active form of vitamin D, 1,25-dihydroxyvitamin D (1,25(OH)(2)D). We further hypothesised that this was secondary to increased synthesis of 1,25(OH)(2)D by inflammatory cells in the intestine. The aim of this study was to examine the relationship between 1,25(OH)(2)D levels and BMD in patients with CD.

METHODS

An IRB approved retrospective review of medical records from patients with CD (n = 138) or ulcerative colitis (UC, n = 29). Measurements of vitamin D metabolites and immunoreactive parathyroid hormone (iPTH) were carried out. BMD results were available for 88 CD and 20 UC patients. Immunohistochemistry or real time reverse transcription-polymerase chain reaction (RT-PCR) for the enzyme 1alpha-hydroxylase was performed on colonic biopsies from patients with CD (14) or UC (12) and normal colons (4).

RESULTS

Inappropriately high levels of serum 1,25(OH)(2)D (>60 pg/ml) were observed in 42% of patients with CD compared with only 7% in UC, despite no differences in mean iPTH. Serum 1,25(OH)(2)D levels were higher in CD (57 pg/ml) versus UC (41 pg/ml) (p = 0.0001). In patients with CD, there was a negative correlation between 1,25(OH)(2)D levels and lumbar BMD (r = -0.301, p = 0.005) independent of therapeutic glucocorticoid use. 1,25(OH)(2)D levels also correlated with CD activity. Lastly, immunohistochemistry and RT-PCR demonstrated increased expression of intestinal 1alpha-hydroxylase in patients with CD.

CONCLUSIONS

These data demonstrate that elevated 1,25(OH)(2)D is more common in CD than previously appreciated and is independently associated with low bone mineral density. The source of the active vitamin D may be the inflamed intestine. Treatment of the underlying inflammation may improve metabolic bone disease in this subgroup of patients.

Anti-Saccharomyces cerevisiae antibody (ASCA) positivity is associated with increased risk for early surgery in Crohn's disease

BACKGROUND

Anti-Saccharomyces cerevisiae antibodies (ASCA) are a specific but only moderately sensitive diagnostic marker for Crohn's disease. We sought to explore the role of ASCA as a prognostic marker for aggressive disease phenotype in Crohn's disease.

AIMS

To determine the role of ASCA status as a risk factor for early surgery in Crohn's disease.

SUBJECTS

We performed a case control study in a cohort of patients, newly diagnosed with Crohn's disease, between 1991 and 1999. All patients were followed for at least three years. Case subjects (n = 35) included those who had major surgery for Crohn's disease within three years of diagnosis. Controls (n = 35) included patients matched to cases for age, sex, disease location, and smoking status, and who did not undergo major surgery for Crohn's disease within three years of diagnosis.

METHODS

Blinded assays were performed on serum for ASCA (immunoglobulin (Ig)A and IgG). A paired analysis of cases-controls was performed to test for the association between ASCA status and risk of early surgery.

RESULTS

ASCA IgA was strongly associated with early surgery (odds ratio (OR) 8.5 (95% confidence interval (CI) 2.0-75.9); p = 0.0013). ASCA IgG+ and ASCA IgG+/IgA+ patients were also at increased risk for early surgery (OR 5.5 (95% CI 1.2-51.1), p = 0.0265; and OR 5.0 (95% CI 1.1-46.9), p = 0.0433, respectively). The association between ASCA and early surgery was evident in patients requiring surgery for ileal or ileocolonic disease.

CONCLUSIONS

Patients with Crohn's disease who are positive for ASCA IgA, IgG, or both, may define a subset of patients with Crohn's disease at increased risk for early surgery.

Deficient host-bacteria interactions in inflammatory bowel disease? The toll-like receptor (TLR)-4 Asp299gly polymorphism is associated with Crohn's disease and ulcerative colitis

BACKGROUND AND AIMS

Elicitation of an innate immune response to bacterial products is mediated through pattern recognition receptors (PRRs) such as the toll-like receptors (TLRs) and the NODs. The recently characterised Asp299Gly polymorphism in the lipopolysaccharide (LPS) receptor TLR4 is associated with impaired LPS signalling and increased susceptibility to Gram negative infections. We sought to determine whether this polymorphism was associated with Crohn's disease (CD) and/or ulcerative colitis (UC).

METHODS

Allele frequencies of the TLR4 Asp299Gly polymorphism and the three NOD2/CARD15 polymorphisms (Arg702Trp, Gly908Arg, and Leu1007fsinsC) were assessed in two independent cohorts of CD patients (cohort 1, n = 334; cohort 2, n = 114), in 163 UC patients, and in 140 controls. A transmission disequilibrium test (TDT) was then performed on 318 inflammatory bowel disease (IBD) trios.

RESULTS

The allele frequency of the TLR4 Asp299Gly polymorphism was significantly higher in CD (cohort 1: 11% v 5%, odds ratio (OR) 2.31 (95% confidence interval (CI) 1.28-4.17), p = 0.004; and cohort 2: 12% v 5%, OR 2.45 (95% CI 1.24-4.81), p = 0.007) and UC patients (10% v 5%, OR 2.05 (95% CI 1.07-3.93), p = 0.027) compared with the control population. A TDT on 318 IBD trios demonstrated preferential transmission of the TLR4 Asp299Gly polymorphism from heterozygous parents to affected children (T/U: 68/34, p = 0.01). Carrying polymorphisms in both TLR4 and NOD2 was associated with a genotype relative risk (RR) of 4.7 compared with a RR of 2.6 and 2.5 for TLR4 and NOD2 variants separately.

CONCLUSION

We have reported on a novel association of the TLR4 Asp299Gly polymorphism with both CD and UC. This finding further supports the genetic influence of PRRs in triggering IBD.

Opposite evolution in incidence of Crohn's disease and ulcerative colitis in Northern France (1988-1999)

BACKGROUND

Northern France was characterised by a high incidence of Crohn's disease (CD) and a low incidence of ulcerative colitis (UC) according to the first inquiry undertaken in the late 1980s.

AIMS

To assess the trends in the incidence of inflammatory bowel disease (IBD) over a 12 year period (1988-1999) in the same area of Northern France.

PATIENTS

Patients living in Northern France (Nord, Pas-de-Calais, Somme, and Seine Maritime--total of 5,790,526 inhabitants) between 1988 and 1999 were included in the study. Case ascertainment was established according to methodology previously described.

METHODS

Trends in incidence were studied using a Poisson regression model in four three year periods (1988-90, 1991-93, 1994-96, and 1997-99) adjusted for age at diagnosis and sex. Incidence rates were standardised for age with the European standard population.

RESULTS

During 1988-99, 7066 cases of IBD were recorded (56.8% CD, 37.7% UC, and 5.5% indeterminate colitis). Mean annual incidence rate of CD increased from 5.2/100,000 inhabitants in 1988-90 to 6.4 in 1997-99 (adjusted p for trend <0.001). In contrast, the incidence of UC decreased from 4.2 to 3.5 (adjusted p for trend <0.001). The ileocolonic subtype of CD increased by 25% even though median age at diagnosis and frequency of digestive investigations were not different.

CONCLUSIONS

Contrary to what has been reported in other countries in Northern Europe, the incidence of CD increased by 23% in 12 years in Northern France while that of UC decreased by 17% during the same period. This indicates that some factors which influence IBD frequency (in both directions) are still at work in this area of Europe, and that further studies aimed at identifying these should be performed. The rising incidence of CD could enhance the burden of this disease on the public health system in France.

Balancing the risks and benefits of infliximab in the treatment of inflammatory bowel disease

Patients with moderate to severely active Crohn's disease treated with infliximab may have a small but real risk of developing severe infections, opportunistic infections, and non-Hodgkin's lymphoma.

Infliximab in inflammatory bowel disease: clinical outcome in a population based cohort from Stockholm County

BACKGROUND

Several placebo controlled studies have demonstrated the efficacy of infliximab in inflammatory bowel disease (IBD) but the potential toxicity of this new biological compound has been less studied.

AIM

To assess the use of infliximab in IBD in a population based cohort, with special emphasis on the occurrence of severe adverse events and mortality.

PATIENTS

All patients with IBD treated with infliximab between 1999 and 2001 in Stockholm County were evaluated.

METHODS

Prospective registration of clinical data was carried out. Retrospective analyses were made of possible adverse events occurring in relation to infliximab treatment. Adverse events requiring pharmacological treatment or hospitalisation were defined as severe. Clinical response was assessed as remission, response, or failure.

RESULTS

A cohort comprising 217 patients was assembled: 191 patients had Crohn's disease (CD), and infliximab was used off label for ulcerative colitis (UC) in 22 patients. Four patients were treated for indeterminate colitis (IC). Mean age was 37.6 (0.9) years (range 8-79). The mean number of infliximab infusions was 2.6 (0.1) (range 1-11). Forty two severe adverse events were registered in 41 patients (CD, n = 35). Eleven of the severe adverse events occurred postoperatively (CD, n = 6). Three patients with CD developed lymphoma (of which two were fatal), opportunistic infections occurred in two patients (one with UC, fatal), and two patients with severe attacks of IBD died due to sepsis (one with CD, one postoperatively with UC). One additional patient with UC died from pulmonary embolism after colectomy. Mean age in the group with fatal outcome was 62.7 years (range 25-79). The overall response rate was 75% and did not differ between the patient groups.

CONCLUSIONS

Infliximab was efficacious as an anti-inflammatory treatment when assessed in a population based cohort of patients with IBD. However, there appear to be a significant risk of deleterious and fatal adverse events, particularly in elderly patients with severe attacks of IBD. Off label use of infliximab in UC and IC should be avoided until efficacy is proven in randomised controlled trials. The underlying risk of developing malignancies among patients with severe or chronically active CD in need of infliximab treatment is not known but the finding of a 1.5% annual incidence of lymphoma emphasises the need for vigilant surveillance with respect to this malignant complication.

Expression and localisation of matrix metalloproteinases and their natural inhibitors in fistulae of patients with Crohn's disease

BACKGROUND

Fistulae are a troublesome complication of Crohn's disease but little is known of the final effector molecules responsible for matrix degradation. Although matrix metalloproteinases (MMPs) have been strongly implicated in tissue injury in Crohn's disease, their role in fistula formation is unknown.

AIM

To determine the expression pattern of MMPs and tissue inhibitors of metalloproteinases (TIMPs) in fistulae of patients with Crohn's disease.

PATIENTS AND METHODS

Resected fistula specimens were obtained from patients with Crohn's disease (n = 11) and classified according to the predominant histological features-that is, acute versus chronic inflammation. Patients with fistulae due to other diseases (n = 9) and normal colon (n = 5) served as controls. MMP and TIMP protein expression was measured by single or double labelled immunohistochemistry, and mRNA expression by in situ hybridisation. MMP activity was measured by gelatin zymography.

RESULTS

Compared with normal colon, strong MMP-3 expression was consistently observed in fistulae in Crohn's disease, irrespective of the stage of inflammatory activity. MMP-3 transcripts and protein were localised in large mononuclear cells and fibroblasts. MMP-9 transcripts and protein were expressed in granulocytes and only in fistulae with acute inflammation. Staining for MMP-1 and MMP-7 was weak and negative for MMP-10, whereas MMP-2 was equally expressed in normal colon and fistulae. TIMP-1, TIMP-2, and TIMP-3 expression was low in all samples. Similar expression patterns were found in fistulae of the disease control group. Fistulae also expressed active MMP-2 and MMP-9, as measured by gelatin zymography.

CONCLUSION

MMP-3 and MMP-9 are markedly upregulated in intestinal fistulae and may contribute to fistula formation through degradation of the extracellular matrix, irrespective of the underlying disease process.

Reduction in diversity of the colonic mucosa associated bacterial microflora in patients with active inflammatory bowel disease

BACKGROUND AND AIMS

The intestinal bacterial microflora plays an important role in the aetiology of inflammatory bowel disease (IBD). As most of the colonic bacteria cannot be identified by culture techniques, genomic technology can be used for analysis of the composition of the microflora.

PATIENTS AND METHODS

The mucosa associated colonic microflora of 57 patients with active inflammatory bowel disease and 46 controls was investigated using 16S rDNA based single strand conformation polymorphism (SSCP) fingerprint, cloning experiments, and real time polymerase chain reaction (PCR).

RESULTS

Full length sequencing of 1019 clones from 16S rDNA libraries (n = 3) revealed an overall bacterial diversity of 83 non-redundant sequences-among them, only 49 known bacterial species. Molecular epidemiology of the composition of the colonic microflora was investigated by SSCP. Diversity of the microflora in Crohn's disease was reduced to 50% compared with controls (21.7 v 50.4; p<0.0001) and to 30% in ulcerative colitis (17.2 v 50.4; p<0.0001). The reduction in diversity in inflammatory bowel disease was due to loss of normal anaerobic bacteria such as Bacteroides species, Eubacterium species, and Lactobacillus species, as revealed by direct sequencing of variable bands and confirmed by real time PCR. Bacterial diversity in the Crohn's group showed no association with CARD15/NOD2 status.

CONCLUSIONS

Mucosal inflammation in inflammatory bowel disease is associated with loss of normal anaerobic bacteria. This effect is independent of NOD2/CARD15 status of patients.

Thalidomide for treatment of severe intestinal bleeding

Apart from its anti-inflammatory activity, which has been used for the treatment of active Crohn's disease, thalidomide is also a potent inhibitor of angiogenesis. We therefore studied the effect of thalidomide in six patients with severe recurrent intestinal bleeding refractory to standard treatment (three patients with Crohn's disease (CD), three patients with obscure intestinal bleeding; mean of 56 blood transfusions within the last 24 months). Bleeding stopped within two weeks after the start of thalidomide in all patients. Haemoglobin normalised without further transfusions for the whole observation period (mean follow up 33 months) while patients needed a mean of 2.2 (CD) and 3.1 (obscure bleeding) blood units/month in the 12 months before treatment. After three months of thalidomide therapy, serum levels of vascular endothelial growth factor were strongly suppressed compared with pretreatment levels. (CD 818 (82) v 129 (86) pg/ml; obscure bleeding 264 (68) v 50 (25) pg/ml). All six patients reported transient fatigue. Peripheral neuropathy was observed in one patient with CD after nine months and was reversible after lowering the dose to 100 mg daily. These results indicate that thalidomide might be useful for patients with otherwise refractory intestinal bleeding.

An interleukin 12 p40-IgG2b fusion protein abrogates T cell mediated inflammation: anti-inflammatory activity in Crohn's disease and experimental colitis in vivo

BACKGROUND AND AIMS

Interleukin-12 (IL-12), a p35/p40 heterodimer, plays a pivotal role in the immune response in Crohn's disease (CD). Since IL-12 p40 dimers act as IL-12 antagonists, we assayed p40 dimer proteins to modulate chronic intestinal inflammation.

METHODS

We generated a fusion protein consisting of the IL-12(p40) subunit fused to the constant region of IgG2b. IL-12(p40)-IgG2b was tested in a murine 2,4,6,-trinitrobenzene sulphonic acid (TNBS) colitis model and in lamina propria mononuclear cells (LPMNC) from patients with CD in vitro.

RESULTS

Dimeric IL-12(p40)-IgG2b fusion protein bound specifically to the IL-12 receptor. In concentrations <10(-7) M, it acted as an IL-12 antagonist as it inhibited interferon gamma (IFN-gamma) secretion, suppressed proliferation, and increased apoptosis of LPMNC from patients with CD. However, in concentrations >10(-6) M, IL-12(p40)-IgG2b increased IFN-gamma secretion and lymphocyte proliferation thereby acting as an IL-12 agonist. In TNBS colitic mice, IL-12(p40)-IgG2b decreased mortality (10% v 68%), prevented body weight loss, reduced tumour necrosis factor alpha, and increased IL-10 secretion.

CONCLUSIONS

The IL-12(p40)-IgG2b fusion protein has dichotomic properties as a specific IL-12 antagonist and selective repressor of mucosal inflammation at low concentration and as an IL-12 agonist at high concentration.

Antibiotic use and the development of Crohn's disease

BACKGROUND

Few environmental determinants of Crohn's disease are well established. Some observational data exist to implicate antibiotic use as a risk factor but these are derived from studies using questionnaires to assess reported antibiotic use that were susceptible to recall bias. We have therefore explored this relationship in prospectively gathered data.

METHODS

We selected incident cases of Crohn's disease from the General Practice Research Database with at least five years of data prior to diagnosis. Controls with five years of complete data were randomly selected. Data were extracted on smoking, drug prescriptions, age, sex, and a variety of symptoms and diagnoses that might be indicative of occult Crohn's disease. Logistic regression was used to investigate the relationship between antibiotic use and Crohn's disease.

RESULTS

A total of 587 Crohn's disease cases and 1460 controls were available for analysis. We found that antibiotic use 2-5 years pre-diagnosis occurred in 71% of cases compared with 58% of controls (p<0.001), and the median number of courses was two in the cases and one in the controls (p<0.001). Adjusting for age, sex, smoking, and use of other drugs, antibiotic use had an odds ratio of 1.32 (1.05-1.65). We were unable to show specificity to any subgroup of antibacterials. Associations similar to that with antibiotics were also found with oral contraceptive, cardiovascular, and neurological drugs.

CONCLUSIONS

We found a statistically significant association between Crohn's disease and prior antibiotic use. This cannot be explained by recall bias, but due to lack of specificity it is unclear whether it is causal.

Proinflammatory cytokines increase glial fibrillary acidic protein expression in enteric glia

BACKGROUND

Enteric glia protect the integrity of the gut, as loss of enteric glial fibrillary acidic protein (GFAP) positive (+) glia leads to a haemorrhagic jejunoileitis. Crohn's disease (CD) and necrotising enterocolitis (NEC) show pathological changes in enteric glia. Therefore, factors controlling GFAP+ enteric glia are of great interest. The aim of the present study was to characterise enteric glia and determine the effect of interleukin 1beta (IL-1beta), interleukin 4 (IL-4), tumour necrosis factor alpha (TNF-alpha), and lipopolysaccharides (LPS) on cultured enteric glia.

METHODS

Dissected rat colon and cultured enteric glia cells were double labelled with anti-GFAP and anti-S-100 antibodies. For regulatory studies, enteric glia cells were treated with cytokines and LPS. Proliferation was assayed using bromodeoxyuridine (BrdU) and mitosis of enteric glia was blocked by demecolcine.

RESULTS

We were able to distinguish GFAP negative (-) from GFAP+ glia subtypes in situ and in primary cultures. Incubation of cells with IL-1beta, TNF-alpha, and LPS led to a significant increase in GFAP+ enteric glia while IL-4 had no effect on GFAP expression. After incubation with IL-1beta, total intracellular GFAP of enteric glia cells was increased. Upregulation of GFAP+ enteric glia could also be observed after stimulation with IL-1beta on blocking mitosis. BrdU uptake in stimulated enteric glia showed no increased proliferation rate.

CONCLUSIONS

Two different types of enteric glia based on GFAP expression exist in the gut. Proinflammatory cytokines and LPS cause a dramatic increase in GFAP+ enteric glia. This suggests that cytokines play an important role in controlling GFAP+ enteric glia which might in turn be involved in modulating the integrity of the bowel during inflammation.

Human ileal bile acid transporter gene ASBT (SLC10A2) is transactivated by the glucocorticoid receptor

BACKGROUND

Patients with Crohn's disease suffer from intestinal bile acid malabsorption. Intestinal bile acid absorption is mediated by the apical sodium dependent bile acid transporter ASBT/IBAT (SLC10A2). In rats, ASBT is induced by glucocorticoids.

AIMS

To study whether human ASBT is activated by glucocorticoids and to elucidate the mechanism of regulation.

PATIENTS AND METHODS

ASBT expression in ileal biopsies from patients with Crohn's disease and from healthy subjects was quantified by western blot. ASBT promoter function was studied in luciferase assays and by electrophoretic mobility shift assay.

RESULTS

In 16 patients with Crohn's disease, ASBT expression was reduced to 69 (7.5)% compared with healthy controls (mean (SEM); p = 0.01). In 10 healthy male volunteers, ASBT protein expression was increased 1.34 (0.11)-fold (mean (SEM); p<0.05) after 21 days' intake of budesonide (9 mg/day) whereas expression of the peptide transporter 1 was unaffected. Reporter constructs of the human ASBT promoter were activated 15-20-fold by coexpression of the glucocorticoid receptor (GR) and exposure to the GR ligands dexamethasone or budesonide. Two glucocorticoid response elements in the ASBT promoter, arranged as inverted hexanucleotide repeats (IR3 elements), conferred inducibility by GR and dexamethasone in a heterologous promoter context and were shown to bind GR in mobility shift assays.

CONCLUSIONS

Human ASBT is induced by glucocorticoids in vitro and in vivo. Induction of ASBT by glucocorticoids could be beneficial in patients with Crohn's disease who exhibit reduced ASBT expression. This study identifies ASBT as a novel target of glucocorticoid controlled gene regulation in the human intestine.

Reversal of abnormal collagen production in Crohn's disease intestinal biopsies treated with regenerating agents

BACKGROUND

Crohn's disease (CD) is characterised by inflammation, muscle layer overgrowth, and collagenous fibrosis of the intestinal tract, with no effective therapy against collagen accumulation.

AIMS

We quantified production of collagen in resection specimens from normal and CD patients and investigated the effect of regenerating agents (RGTAs) on collagen production. RGTAs are chemically substituted dextrans engineered to mimic the growth factor protecting effects of heparan sulphates. RGTAs have been shown to enhance tissue repair in various in vivo models and to modulate in vitro collagen phenotype differentially according to their structure.

PATIENTS

We studied intestinal biopsies from two groups of CD patients: treated with glucocorticoids (CD-GC group: 10 patients) or not treated (CD group: seven patients), and from seven control patients.

METHODS

After 24 hours of ex vivo incubation with (3H) proline, collagen I, III, and V were extracted by pepsin and quantitatively separated by sodium dodecyl sulphate-polyacrylamide gel electrophoresis. Biosynthesis of each collagen type was quantified on radiolabelled isolated collagen.

RESULTS

Total intestinal collagen production in CD patients compared with controls was increased up to 3.5-fold overall (p<0.001). In particular, collagen III biosynthesis was enhanced by 6.2-fold (p<0.001) in CD patients. In the CD-GC group, collagen production abnormalities were less marked. RGTAs added to the incubation medium in the CD group decreased total collagen production by 50% and decreased collagen III synthesis by 76%.

CONCLUSION

This finding offers a rationale for using RGTAs in the treatment of intestinal fibrosis in CD, thus opening up a potential new therapeutic field for this family of drugs.