Growth, Congo Red agar colony morphotypes and antibiotic susceptibility testing of Mycobacterium avium subspecies paratuberculosis

OBJECTIVE

Mycobacterium avium subspecies (subsp.) paratuberculosis (MAP) is the causative agent of Johne's disease in ruminants and has been associated with Crohn's disease in humans. We sought to test growth rates and susceptibilities of various strains of MAP in two available growth media.

DESIGN

Paired comparison design.

METHODS

Using the BACTEC macrobroth radiometric growth system and Congo Red-staining agar media, we determined inherent differences in growth characteristics of three bovine and two human strains of MAP and compared susceptibility results obtained in each growth system.

RESULTS

Significant differences were observed in growth rate as well as mycobactin J dependence between strains and between a laboratory-adapted isolate of the same strain in the macrobroth system. Similarly, colonial morphology and Congo Red staining on agar media were observed. Two strains, one human and one bovine, demonstrated a 100% rough transparent colony with white coloration on Congo Red agar, while one bovine isolate exclusively grew as a smooth opaque colony with red coloration on Congo Red agar. The remaining strains exhibited mixtures of these two colonial morphotypes on agar media. Comparative susceptibility results between the BACTEC radiometric macrobroth method and the agar proportionality method showed good correlation for most antibiotics/inhibitors tested. However, erratic or poor growth in the macrobroth system prevented minimal inhibitory concentration determinations for two bovine strains by this method.

CONCLUSION

This study demonstrates the variability in the colonial morphology of MAP on Congo Red agar as well as the correlation of antibiotic susceptibility results between the BACTEC macro broth method and the agar proportionality method. This study also emphasizes the need for the development of improved, standardized culture and susceptibility test methods for MAP.

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.

Lymphocytic colitis: a retrospective clinical study of 199 Swedish patients

BACKGROUND

Lymphocytic colitis is characterised by chronic diarrhoea and specific microscopic changes in a macroscopically normal colonic mucosa. We report clinical features and treatment outcome in a large patient cohort.

METHODS

Patients were searched for in 24 Swedish gastroenterology clinics. The biopsy material was reassessed using strict histopathological criteria. Clinical data were obtained from medical notes.

RESULTS

Lymphocytic colitis was diagnosed in 199 cases. The female:male ratio was 2.4:1. Median age at diagnosis was 59 (48-70) years. The most frequent symptoms were diarrhoea (96%), abdominal pain (47%), and weight loss (41%). The course was chronic intermittent in 30% of patients, chronic continuous in 7%, and a single attack in 63%, and in these cases the disease duration was 6 (4-11) months. Seventy nine (40%) patients reported associated diseases, of which thyroid disorders, coeliac disease, and diabetes mellitus were the most common. In 34 first or second degree relatives of 24 (12%) patients, a family history of ulcerative colitis, Crohn's disease, collagenous colitis, or coeliac disease was reported. Drug induced disease was suspected in 19 (10%) patients. A non-significant peak of disease onset was seen in December-January. More than 80% of treated patients improved on corticosteroids, including budesonide.

CONCLUSIONS

A family history of other bowel disorders is a new finding. The sudden onset and single attack of limited duration may support a possible infectious cause in some cases. Drugs may cause lymphocytic colitis.

Is inflammatory bowel disease an independent and disease specific risk factor for thromboembolism?

BACKGROUND

Patients with inflammatory bowel disease (IBD) are thought to be at increased risk of venous thromboembolism (TE). However, the extent of this risk is not known. Furthermore, it is not known if this risk is specific for IBD or if it is shared by other chronic inflammatory diseases or other chronic bowel diseases.

AIMS

To compare the risk of TE in patients with IBD, rheumatoid arthritis, and coeliac disease with matched control subjects.

PATIENTS AND METHODS

Study subjects answered a questionnaire assessing the history of TE, any cases of which had to be confirmed radiologically. A total of 618 patients with IBD, 243 with rheumatoid arthritis, 207 with coeliac disease, and 707 control subjects were consecutively included. All three patient groups were compared with control subjects matched to the respective group by age and sex.

RESULTS

Thirty eight IBD patients (6.2%) had suffered TE. This was significantly higher compared with the matched control population with only 10 cases reported (1.6%) (p<0.001; odds ratio (OR) 3.6 (95% confidence interval (CI) 1.7-7.8)). Five patients with rheumatoid arthritis (2.1%) had suffered TE compared with six subjects (2.5%) in the control population matched to patients with rheumatoid arthritis (NS; OR 0.7 (95% CI 0.2-2.9)). TE had occurred in two patients with coeliac disease (1%) compared with four subjects (1.9%) in the control population matched to the coeliac disease group (NS; OR 0.4 (95% CI 0.1-2.5)). In 60% of TE cases in the IBD group, at least one IBD specific factor (active disease, stenosis, fistula, abscess) was present at the time TE occurred.

CONCLUSIONS

IBD is a risk factor for TE. It seems that TE is a specific feature of IBD as neither rheumatoid arthritis, another chronic inflammatory disease, nor coeliac disease, another chronic bowel disease, had an increased risk of TE.

Increased antigen and bacterial uptake in follicle associated epithelium induced by chronic psychological stress in rats

BACKGROUND

Chronic stress affects the course of inflammatory bowel disease and experimental colitis, and may also initiate intestinal inflammation in rats.

AIM

To investigate the effects of stress on the M cell containing follicle associated epithelium, specialised in antigen uptake.

SUBJECTS AND METHODS

Wistar rats were submitted to acute water avoidance stress for one hour or chronic water avoidance stress for 1 hour/day for 10 consecutive days. Permeability to (51)Cr-EDTA, horseradish peroxidase, and chemically killed Escherichia coli K-12 was studied in both villus and follicle associated epithelium in Ussing chambers. Segments were further examined by light, electron, and confocal microscopy.

RESULTS

Acute stress increased horseradish peroxidase flux in villus as well as in follicle associated epithelium. Chronic stress further increased permeability to horseradish peroxidase in villus and follicle associated epithelium, in the latter by almost fourfold. Moreover, chronic stress induced over 30 times increased E coli passage in follicle associated epithelium whereas there was no significant increase in villus epithelium. Bacterial uptake was confirmed by confocal microscopy showing fluorescent bacteria penetrating and passing through the epithelial surface.

CONCLUSIONS

These results show that the barrier function of follicle associated epithelium can be modulated, and that chronic stress enhances the uptake of luminal antigens and bacteria via the follicle associated epithelium. This can increase antigen exposure in Peyer's patches thereby having implications in the initiation of proinflammatory immune responses within the intestinal mucosa.

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.

Malignant peritoneal mesothelioma in a pediatric patient mimicking inflammatory bowel disease

Malignant peritoneal mesothelioma is a rare malignancy of the serosal membranes that is difficult to diagnose and carries a poor prognosis. Progression of presenting symptoms is slow and nonspecific. Diffuse peritoneal seeding by the neoplasm can present silently so that physical abnormalities may not be detected until the disease is far advanced. Standard laboratory and radiographic studies can also be inconclusive. We report a case of an adolescent female whose clinical presentation and initial response to management were consistent with inflammatory bowel disease (IBD) but who was ultimately diagnosed with malignant peritoneal mesothelioma.

Lymphocyte homing in the pathogenesis of extra-intestinal manifestations of inflammatory bowel disease

Inflammatory bowel disease is associated with extra-intestinal manifestations which occur either at the same time as flares of bowel inflammation (skin and eye disease) or run a course that is independent to inflammation in the bowel (liver and some joint syndromes). It has been suggested that the skin and eye complications occur as a consequence of the recruitment of activated effector cells released from the gut into the circulation to extra-intestinal site where they cause acute damage. However, this does not explain how patients can develop primary sclerosing cholangitis many years after having their colon removed for colitis. We propose that long-lived populations of memory lymphocytes arise as a consequence of bowel inflammation and that these cells express homing receptors that direct their subsequent migration not only to the gut but also to the liver. These long-lived cells may recirculate to the liver for many years and, in the absence of a local activating stimulus, will not cause damage. However, if they are subsequently activated in the liver this will lead to the development of inflammation and tissue damage which promotes the recruitment of more mucosal lymphocytes resulting in persistent inflammation and disease. The recent findings that MAdCAM-1 and CCL25, previously thought to be restricted to the gut, are up-regulated in the liver during inflammatory liver diseases that complicate IBD support the concept that common mechanisms control lymphocyte recruitment to the inflamed liver and gut.

Modulating the intestinal immune system: the role of lymphotoxin and GALT organs

The gut associated immune system fences off potentially harmful intestinal antigens from the systemic circulation and induces systemic tolerance against luminal antigens. Intestinal immune responses against luminal antigens include IgA secretion and induction of regulatory cells. Unlike few other cytokines, lymphotoxin alpha/beta regulates the development of intestinal lymphoid organs. The embryonic development of Peyer's patches, postnatal lamina propria B cell development, and isolated lymphoid follicle development all depend on lymphotoxin beta receptor interactions. Lymphotoxin alpha/beta signalling also contributes to the development of mesenteric lymph nodes. In addition, intestinal inflammation is suppressed by inhibition of lymphotoxin beta signalling, an observation which has initiated clinical studies using this treatment principal. Intestinal follicular lymphoid organs are sites of antigen presentation. Antigen presenting cells tune the delicate balance between intestinal immune tolerance and inflammation. Therefore, gut associated lymphatic organs and factors regulating their development are critical for the prevention of adverse immune reactions to intestinal antigens. This review provides an overview on the role of lymphotoxin and the gut associated lymphatic organs in the regulation of oral tolerance and intestinal inflammation.

Hip fractures in patients with inflammatory bowel disease and their relationship to corticosteroid use: a population based cohort study

BACKGROUND

Inflammatory bowel disease (IBD) is known to be associated with reduced bone density but the extent to which this results in an increased risk of fracture and the contribution of corticosteroid therapy are unclear. We have conducted a large cohort study to address these issues.

METHODS

We selected subjects within the General Practice Research Database (GPRD) with a diagnosis of IBD and up to five matched controls for each patient. We derived dates of recorded hip fractures and also information on smoking, use of corticosteroids, and a number of other drugs. We calculated the absolute risk of fracture and the relative risk as a hazard ratio corrected for available confounders by Cox regression.

RESULTS

Seventy two hip fractures were recorded in 16 550 IBD cases and 223 in 82 917 controls. Cox modelling gave an unadjusted relative risk of hip fracture of 1.62 (95% confidence interval (CI) 1.24-2.11) for all IBD, 1.49 (1.04-2.15) for ulcerative colitis (UC) and 2.08 (1.36-3.18) for Crohn's disease (CD). Multivariate modelling showed that both current and cumulative use of corticosteroids and use of opioid analgesics confounded this relationship. After adjusting for confounding, the relative risk was 1.41 (0.94-2.11) for UC and 1.68 (1.01-2.78) for CD.

CONCLUSION

The risk of hip fracture is increased approximately 60% in IBD patients. Corticosteroid use is a contributor to this, both in the long term as previously recognised and also in an acute reversible manner. The majority of hip fracture risk in IBD patients however cannot be attributed to steroid use.

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.

Dysbiosis in inflammatory bowel disease

Abundant data have incriminated intestinal bacteria in the initiation and amplification stages of inflammatory bowel diseases. However, the precise role of intestinal bacteria remains elusive. One theory has suggested a breakdown in the balance between putative species of "protective" versus "harmful" intestinal bacteria--this concept has been termed "dysbiosis". Arguments in support of this concept are discussed.

Systemic antibodies towards mucosal bacteria in ulcerative colitis and Crohn's disease differentially activate the innate immune response

BACKGROUND AND AIMS

The mucosa in ulcerative colitis (UC) is replete with antibody producing plasma B cells and polymorphonuclear leucocytes (PMN). This combination of effector cells requires a crosslinking antigen to evoke an antibody driven PMN inflammatory response via their Fc receptors. The stimulus for activation is thought to be commensal bacteria colonising the gut mucosa. The aim of this investigation was to compare the principal culturable bacterial populations on the rectal mucosa of UC patients, and to determine whether specific antibodies towards these bacteria can activate infiltrating PMN through opsonisation. This would provide an explanation for this chronic inflammatory condition.

METHODS

Bacteria colonising rectal tissue were characterised using chemotaxonomic techniques. Systemic antibody responses were measured against total antigens and surface antigens of these organisms in UC and Crohn's disease (CD) patients, together with healthy controls. Antibody enhancement of the respiratory burst in PMN was also investigated, against a range of mucosal isolates.

RESULTS

Distinct differences were observed in some bacterial populations in UC biopsies, which were generally reflected in antibody responses towards these organisms. UC patients had higher IgG responses to surface antigens, primarily IgG1, whereas the response in CD was mainly IgG2. Antibodies from UC patients greatly enhanced the respiratory burst in PMN, in response to individual bacterial species.

CONCLUSIONS

Changes in mucosal bacteria, and a switch from internal to surface antigen/antibody reactivity of a predominantly IgG1 type, leads to greater opsonisation of the respiratory burst in PMN, providing a mechanism for maintaining the inflammatory state in UC.

Concurrent infection with Schistosoma mansoni attenuates inflammation induced changes in colonic morphology, cytokine levels, and smooth muscle contractility of trinitrobenzene sulphonic acid induced colitis in rats

BACKGROUND AND AIMS

Crohn's disease, characterised by chronic T helper 1 (Th1) inflammation and dysmotility of the gut, is most prevalent in developed countries. Parasitic infections are most prevalent in developing countries and induce a T helper 2 (Th2) immune response. We hypothesised that this Th2 immune response protects against Th1 gut inflammation.

METHODS

The parasite Schistosoma mansoni induces a transient Th2 immune response in the semipermissive rat host. 2,4,6-Trinitrobenzene sulphonic acid (TNBS) induced colitis is an experimental model of Th1-like gut inflammation. The effect of concurrent infection with S mansoni on the course of TNBS induced colitis was assessed using macroscopic and microscopic damage scores, histology, myeloperoxidase (MPO) activity assay, cytokine production assay, and by studying in vitro contractility of longitudinal and circular colonic muscle strips.

RESULTS

TNBS induced colitis that spontaneously healed after four weeks. Concurrent infection with S mansoni significantly reduced the duration of TNBS induced colitis to two weeks, as shown by macroscopic and microscopic damage scores and by a faster decrease in colonic MPO activity. TNBS increased colonic interleukin 2 (IL-2) production whereas S mansoni increased splenic IL-4 and IL-2 levels. Contractility of longitudinal and circular muscle strips was maximally inhibited one week after TNBS and normalised after three weeks. After four weeks, longitudinal muscle strip contractility was significantly increased. Concurrent infection with S mansoni normalised longitudinal muscle contractility after one week whereas circular muscle contractility remained inhibited.

CONCLUSIONS

Concurrent infection with S mansoni significantly attenuates TNBS induced colitis in the rat. Inflammation induced disturbances in contractility of longitudinal and circular colonic muscle strips may outlast the inflammatory reaction.

Aetiology of colorectal cancer and relevance of monogenic inheritance

BACKGROUND AND AIMS

Although diet and lifestyle are associated with the development of colorectal malignancies, the only clearly identified aetiological factors in colorectal cancer are inheritance (hereditary non-polyposis colorectal cancer (HNPCC) and familial polyposis), inflammatory bowel diseases, papillomavirus, and acquired immunodeficiency syndrome (AIDS). Our aim was to determine what proportion of colorectal neoplasms could be attributed to these specific factors.

PATIENTS AND METHODS

Data from a colorectal cancer registry were analysed over a 15 year period, during which nearly 2500 cases were recorded. In patients with suspected HNPCC, microsatellite instability and immunohistochemical expression of proteins encoded by the main DNA mismatch repair genes were assessed. In families with unstable neoplasms, constitutional mutations of the mismatch repair genes hMSH2, hMLH1, and hMSH6 were evaluated by single strand conformation polymorphism analysis and sequencing.

RESULTS

Inflammatory bowel diseases, familial polyposis, and AIDS were rare causes of colorectal cancer (three, three, and one case, respectively). Anal squamous carcinoma developed in 27 patients (1.0%) and could be attributed to papillomavirus infection. In 58 patients (from 34 families) a clinical diagnosis of HNPCC was established (2.4%). In total, cases with a known aetiology were 92 (3.7% of all patients). Microsatellite instability was detected in 15 cancers from HNPCC families, and germline mutations in six families (12 patients, 0.5% of the total). Families with unstable tumours, with or without mutations, were clinically similar, suggesting the involvement of the mismatch repair system even when mutations were not detected.

CONCLUSIONS

The study suggests that the aetiology of colorectal malignancies remains elusive in the large majority of cases. Among specific causes, HNPCC represents the most frequent. However, with a population based approach, constitutional mutations of the main genes involved in HNPCC can be detected in only 20% of cases.

Dark lumen magnetic resonance colonography: comparison with conventional colonoscopy for the detection of colorectal pathology

BACKGROUND

The purpose of this study was to assess the feasibility and usefulness of a new magnetic resonance (MR) colonography technique for the detection of colorectal pathology in comparison with conventional colonoscopy as the standard of reference.

PATIENTS AND METHODS

A total of 122 subjects with suspected colorectal disease underwent "dark lumen" MR colonography. A contrast enhanced T1w three dimensional VIBE sequence was collected after rectal administration of water. The presence of colorectal masses and inflammatory lesions were documented. Results were compared with those of a subsequently performed colonoscopy.

RESULTS

MR colonography was found to be accurate regarding detection of clinically relevant colonic lesions exceeding 5 mm in size, with sensitivity and specificity values of 93%/100%.

CONCLUSION

Dark lumen MR colonography can be considered as a promising alternative method for the detection of colorectal disease. In addition, it allows assessment of extraluminal organs.

Activated platelets are the source of elevated levels of soluble CD40 ligand in the circulation of inflammatory bowel disease patients

BACKGROUND

The CD40/CD40L system, a key regulator and amplifier of immune reactivity, is activated in inflammatory bowel disease (IBD) mucosa.

AIMS

To determine whether plasma levels of sCD40L are elevated in Crohn's disease (CD) and ulcerative colitis (UC) patients compared with normal controls, to investigate the cellular source of sCD40L, and to explore CD40L induction mechanisms.

PATIENTS

CD, UC, and normal control subjects were studied.

METHODS

The concentration of sCD40L in plasma and supernatants of freshly isolated platelets and autologous peripheral blood T cells (PBT) was measured by ELISA. Surface CD40L expression level was measured by flow cytometry in resting and thrombin activated platelets, and unstimulated and CD3/CD28 stimulated PBT before and after coculture with human intestinal microvascular endothelial cells (HIMEC).

RESULTS

Compared with normal controls, plasma sCD40L levels were significantly higher in both CD and UC patients and proportional to the extent of mucosal inflammation. Platelets from IBD patients displayed a significantly higher surface CD40L expression than those from control subjects, and released greater amounts of sCD40L than autologous PBT. Contact with IL-1beta activated HIMEC induced significant upregulation of CD40L surface expression and release by platelets.

CONCLUSIONS

Elevated levels of sCD40L in the circulation of IBD patients reflect enhanced surface expression and release of CD40L by platelets. This phenomenon translates to an increased platelet activation state apparently induced by passage through an inflamed mucosal microvascular bed, a conclusion supported by the positive correlation of plasma sCD40L levels with the extent of anatomical involvement by IBD. These results suggest that platelet-endothelial interactions critically contribute to activation of the CD40 pathway in IBD.

Evaluation of new therapies for inflammatory bowel disease

The pathophysiology of inflammatory bowel disease (IBD) is gradually being unravelled and new therapies are being developed to target the disturbed biological processes. This article outlines the clinical features of IBD, its current therapy and pathogenesis. The difficulties for clinical pharmacologists and gastroenterologists associated with designing, executing and interpreting clinical trials in IBD are then discussed. The final section reviews methods that can used to demonstrate the pharmacological actions of new treatments in patients with IBD. It is emphasized that proof of the therapeutic efficacy of a novel agent with a specific mechanism of action yields not only clinical benefit to patients with IBD, but also indicates the importance of the targeted biochemical pathway in the pathogenesis of the disease.

The dendritic cell: its role in intestinal inflammation and relationship with gut bacteria

Dendritic cells are antigen presenting cells that are likely to be pivotal in the balance between tolerance and active immunity to commensal microorganisms that is fundamental to inflammatory conditions, including Crohn's disease and ulcerative colitis. Interactions between dendritic cells and microbial products are discussed and how they contribute to regulation of immune responses. The concept that interactions between dendritic cells and commensal organisms may be responsible for maintaining intestinal immune homeostasis is also explored.

Changing pattern of paediatric inflammatory bowel disease in northern Stockholm 1990-2001

BACKGROUND

An increased incidence of paediatric Crohn's disease was reported recently by our group.

AIMS

To assess the incidence and characteristics of inflammatory bowel disease (IBD) in northern Stockholm between 1990 and 2001.

METHODS

All records of individuals 0-15 years of age with suspected IBD in the population based catchment area of 180000 individuals were scrutinised using defined diagnostic criteria. Patient files were searched for relatives with IBD, and for concomitant autoimmune diseases.

RESULTS

A total of 152 children were diagnosed with IBD, corresponding to an overall incidence (per 100000) of IBD of 7.4. The incidence of Crohn's disease (CD) was 4.9, ulcerative colitis (UC) 2.2, and indeterminate colitis 0.2. Between 1990 and 2001, there was a marked increase in the incidence of CD while the incidence of UC was almost unchanged, leading to a net increase in the overall occurrence of IBD. There was a male dominance of CD. Fourteen per cent and 11% of patients with CD and UC, respectively, had a first or second degree relative with IBD. Eighteen per cent and 10% of patients with CD and UC, respectively, had a concomitant autoimmune disease. Ten patients with CD (10%) underwent surgery.

CONCLUSIONS

The incidence of CD has increased in northern Stockholm. The current incidence is higher than that reported from other areas. Our results suggest a shift in presentation and diagnosis from UC towards CD, but also a net increase in IBD. Concomitant autoimmune disorders and family history are common in paediatric IBD.

Inducible CD40 expression mediates NFkappaB activation and cytokine secretion in human colonic fibroblasts

BACKGROUND

CD40 has been shown to be a functional activation antigen on a variety of cell types involved in immune responses. As intestinal fibroblasts and myofibroblasts may play a role during mucosal inflammation, we investigated the functional consequences of CD40 induction in primary cultures of human colonic fibroblasts.

METHODS

Primary colonic lamina propria fibroblasts (PCLF) were isolated from endoscopic biopsies and surgical specimens. Cultures were used between passages 3 and 9. CD40 surface display was determined by FACS analysis and mRNA expression by reverse transcription-polymerase chain reaction. Secretion of cytokines was determined by ELISA. Nuclear factor kappaB (NFkappaB) activation was shown by electrophoretic mobility shift assay (EMSA).

RESULTS

After priming with interferon gamma (IFN-gamma) (200 U/ml) for 72 hours, five of eight tested PCLF cultures showed induction of CD40 surface display (up to 10-fold). Induction of CD40 mRNA expression was demonstrated by semiquantitative polymerase chain reaction. In the responder-PCLF cultures, IFN-gamma alone caused a 1.5-5-fold increase in interleukin (IL)-8 secretion. Addition of 1 ng/ml CD40L was sufficient to achieve a further increase in IL-8, IL-6, or monocyte chemotactic protein 1 (MCP-1) secretion (2.5-18-fold of controls). Incubation with CD40L alone without priming with IFN-gamma had no effect. The proteasome inhibitor N-acetyl-leucinyl-leucinyl-norleucinal (ALLN 100 microM) reduced IFN-gamma/CD40L mediated cytokine induction, suggesting participation of NFkappaB, which was directly demonstrated by EMSA. CD4+ T cells induced MCP-1 secretion by PCLF, which was prevented by addition of an excess of CD40-IgG fusion protein. CD40 expression on PCLF could also be demonstrated in vivo by immunohistochemistry.

CONCLUSION

The CD40-CD40L pathway augments mucosal inflammatory responses via mucosal PCLF. CD40-CD40L mediated T cell/PCLF interactions could play an important role during intestinal mucosal inflammation.

Interferon beta-1a in ulcerative colitis: a placebo controlled, randomised, dose escalating study

BACKGROUND

and aims: Administration of interferon (IFN)-beta may represent a rational approach to the treatment of ulcerative colitis through its immunomodulatory and anti-inflammatory effects. The present study was performed to evaluate the efficacy and tolerability of IFN-beta-1a.

METHODS

Patients (n=18) with moderately active ulcerative colitis were randomised to receive IFN-beta-1a or placebo. IFN-beta-1a was started at a dose of 22 micro g three times a week subcutaneously, and the dose was increased at two week intervals to 44 micro g and then to 88 micro g if no response was observed. The maximum duration of treatment was eight weeks. End points were clinical treatment response, defined as a decrease of at least 3 points from baseline in the ulcerative colitis scoring system (UCSS) symptoms score and induction of endoscopically confirmed remission.

RESULTS

Baseline characteristics and disease severity were similar in both groups. Data from 17 patients are included in this report (10 patients in the IFN-beta-1a group and seven patients in the placebo group). Clinical response was achieved in five patients (50%) in the IFN-beta-1a group and in one (14%) in the placebo group (P=0.14). Remission was achieved in three patients in the IFN-beta-1a group and in none in the placebo group (p=0.02). Most adverse reactions associated with IFN-beta-1a were influenza-like symptoms or injection site reactions, and were mild or moderate in severity.

CONCLUSIONS

IFN-beta-1a may represent a promising novel treatment approach in ulcerative colitis.

Infliximab in moderately severe glucocorticoid resistant ulcerative colitis: a randomised controlled trial

BACKGROUND

Tumour necrosis factor production is increased in the mucosa of patients with active ulcerative colitis. The benefits of infliximab in Crohn's disease are established. We investigated its efficacy in ulcerative colitis.

METHODS

We conducted a randomised placebo controlled trial of infliximab (5 mg/kg) in the treatment of glucocorticoid resistant ulcerative colitis. Infusions were given at weeks 0 and 2. Disease activity and quality of life were recorded over eight weeks of follow up. Remission was defined as an ulcerative colitis symptom score (UCSS) of < or =2 and/or Baron score of 0 at week 6. Patients not in remission were offered open label infliximab 10 mg/kg and reviewed two weeks later.

RESULTS

After two weeks, there was no statistically significant difference between the infliximab and placebo groups in the proportion of patients with a Baron score of 0 (13% (3/23) v 5% (1/19) (95% confidence interval (CI) -9% to 24%); p=0.74). After six weeks, remission (UCSS < or =2) rates were 39% (9/23) versus 30% (6/20) (95% CI -19 to 34%; p=0.76). The median improvement in UCSS was 3 for the infliximab group and 2.5 for the placebo group (p=0.82, Mann-Whitney U test). A Baron score of 0 was likely in either group (26% (6/23) v 30% (6/20) (95% CI -30% to 23%); p=0.96). Improvement in the IBDQ and EuroQol was not significantly different between the groups (p=0.22 and 0.3, respectively, Mann-Whitney U test). Twenty eligible patients were given open labelled infusions. Remission was achieved in 3/11 (27%) patients initially treated with infliximab and in 1/9 (11%) patients treated with placebo.

CONCLUSION

These data do not support the use of infliximab in the management of moderately active glucocorticoid resistant ulcerative colitis.

Absence of Mycobacterium avium subspecies paratuberculosis components from Crohn's disease intestinal biopsy tissues

BACKGROUND

Crohn's disease is a chronic human intestinal inflammatory disorder for which an etiologic agent has not been identified. Johne's disease is a similar chronic enteric granulomatous disease of ruminant species and has been used as a model of Crohn's disease. Johne's disease has been proven to be caused by Mycobacterium avium subspecies paratuberculosis (M. avium ss paratuberculosis). It has been proposed that M. avium ss paratuberculosis may also cause Crohn's disease. This is of particular concern because the organism may be spread to humans through inadequately pasteurized dairy products.

OBJECTIVE

We sought to determine whether M. avium ss paratuberculosis could be detected using identical techniques in paraffin-embedded tissue samples of bovine Johne's disease and human Crohn's, ulcerative colitis and diverticular diseases. Samples were obtained for analysis from national tissue banks.

DESIGN

Cross-species and cross-disease sample comparisons by multiple detection techniques.

METHODS

Histology, immunocytochemistry and polymerase chain reaction (PCR) were utilized to test and compare the presence of M. avium ss paratuberculosis components. Insertion sequence IS900, present in multiple copies and found only in M. avium ss paratuberculosis, was utilized in both PCR and immunocytochemical analyses.

RESULTS

The IS900 sequence was demonstrable in all samples of confirmed positive Johne's disease tissue. The sequence was not identified in the 35 Crohn's, 36 ulcerative colitis, and 21 diverticular disease samples.

CONCLUSION

M. avium ss paratuberculosis was not associated with the lesions in these Crohn's disease samples, using these methods.

Multidrug resistance 1 gene (P-glycoprotein 170): an important determinant in gastrointestinal disease?

The interface between luminal contents and intestinal epithelium constitutes the largest area of interaction between the host and the environment. There is now strong evidence that the gene product of the multidrug resistant pump (MDR) plays a critical role in host-bacterial interactions in the gastrointestinal tract and maintenance of intestinal homeostasis. This review highlights the efflux mechanism in the intestinal epithelium which is mediated by the multidrug resistant pump, also known as P-glycoprotein 170. Current studies promise to provide further insights into the contribution of the MDR1 gene in the pathogenesis of inflammatory and malignant disorders of the gastrointestinal tract.

Increases in free radicals and cytoskeletal protein oxidation and nitration in the colon of patients with inflammatory bowel disease

BACKGROUND

Overproduction of colonic oxidants contributes to mucosal injury in inflammatory bowel disease (IBD) but the mechanisms are unclear. Our recent findings using monolayers of intestinal cells suggest that the mechanism could be oxidant induced damage to cytoskeletal proteins. However, oxidants and oxidative damage have not been well characterised in IBD mucosa.

AIMS

To determine whether there are increases in oxidants and in tissue and cytoskeletal protein oxidation in IBD mucosa.

METHODS

We measured nitric oxide (NO) and markers of oxidative injury (carbonylation and nitrotyrosination) to tissue and cytoskeletal proteins in colonic mucosa from IBD patients (ulcerative colitis, Crohn's disease, specific colitis) and controls. Outcomes were correlated with IBD severity score.

RESULTS

Inflamed mucosa showed the greatest increases in oxidants and oxidative damage. Smaller but still significant increases were seen in normal appearing mucosa of patients with active and inactive IBD. Tissue NO levels correlated with oxidative damage. Actin was markedly (>50%) carbonylated and nitrated in inflamed tissues of active IBD, less so in normal appearing tissues. Tubulin carbonylation occurred in parallel; tubulin nitration was not observed. NO and all measures of oxidative damage in tissue and cytoskeletal proteins in the mucosa correlated with IBD severity. Disruption of the actin cytoarchitecture was primarily within the epithelial cells and paracellular area.

CONCLUSIONS

Oxidant levels increase in IBD along with oxidation of tissue and cytoskeletal proteins. Oxidative injury correlated with disease severity but is also present in substantial amounts in normal appearing mucosa of IBD patients, suggesting that oxidative injury does not necessarily lead to tissue injury and is not entirely a consequence of tissue injury. Marked actin oxidation (>50%)-which appears to result from cumulative oxidative damage-was only seen in inflamed mucosa, suggesting that oxidant induced cytoskeletal disruption is required for tissue injury, mucosal disruption, and IBD flare up.

Curcumin, the major component of food flavour turmeric, reduces mucosal injury in trinitrobenzene sulphonic acid-induced colitis

1 Inflammmatory bowel disease (IBD) is characterized by oxidative and nitrosative stress, leucocyte infiltration and upregulation of proinflammatory cytokines. In this study, we have investigated the protective effects of curcumin, an anti-inflammatory and antioxidant food derivative, on 2,4,6- trinitrobenzene sulphonic acid-induced colitis in mice, a model for IBD. 2 Intestinal lesions (judged by macroscopic and histological score) were associated with neutrophil infiltration (measured as increase in myeloperoxidase activity in the mucosa), increased serine protease activity (may be involved in the degradation of colonic tissue) and high levels of malondialdehyde (an indicator of lipid peroxidation). 3 Dose-response studies revealed that pretreatment of mice with curcumin (50 mg kg(-1) daily i.g. for 10 days) significantly ameliorated the appearance of diarrhoea and the disruption of colonic architecture. Higher doses (100 and 300 mg kg(-1)) had comparable effects. 4 In curcumin-pretreated mice, there was a significant reduction in the degree of both neutrophil infiltration (measured as decrease in myeloperoxidase activity) and lipid peroxidation (measured as decrease in malondialdehyde activity) in the inflamed colon as well as decreased serine protease activity. 5 Curcumin also reduced the levels of nitric oxide (NO) and O(2)(-) associated with the favourable expression of Th1 and Th2 cytokines and inducible NO synthase. Consistent with these observations, nuclear factor-kappaB activation in colonic mucosa was suppressed in the curcumin-treated mice. 6 These findings suggest that curcumin or diferuloylmethane, a major component of the food flavour turmeric, exerts beneficial effects in experimental colitis and may, therefore, be useful in the treatment of IBD.

Analysis of the IBD5 locus and potential gene-gene interactions in Crohn's disease

BACKGROUND AND AIMS

Genetic variation in the chromosome 5q31 cytokine cluster (IBD5 risk haplotype) has been associated with Crohn's disease (CD) in a Canadian population. We studied the IBD5 risk haplotype in both British and Japanese cohorts. Disease associations have also been reported for CARD15/NOD2 and TNF variants. Complex interactions between susceptibility loci have been shown in animal models, and we tested for potential gene-gene interactions between the three CD associated loci.

METHODS

Family based association analyses were performed in 457 British families (252 ulcerative colitis, 282 CD trios) genotyped for the IBD5 haplotype, common CARD15, and TNF-857 variants. To test for possible epistatic interactions between variants, transmission disequilibrium test analyses were further stratified by genotype at other loci, and novel log linear analyses were performed using the haplotype relative risk model. Case control association analyses were performed in 178 Japanese CD patients and 156 healthy controls genotyped for the IBD5 haplotype.

RESULTS

The IBD5 haplotype was associated with CD (p=0.007), but not with UC, in the British Caucasian population. The CARD15 variants and IBD5 haplotype showed additive main effects, and in particular no evidence for epistatic interactions was found. Variants from the IBD5 haplotype were extremely rare in the Japanese.

CONCLUSIONS

The IBD5 risk haplotype is associated with British CD. Genetic variants predisposing to CD show heterogeneity and population specific differences.

Isolation of peptides useful for differential diagnosis of Crohn's disease and ulcerative colitis

BACKGROUND

Phage displayed random peptide technology has been utilised to identify binding epitopes of antibodies or receptor ligands.

AIM

To isolates peptides from a phage library which are specifically recognised by antibodies in serum from patients with Crohn's disease (CD).

METHODS

A phage displayed random peptide library composed of nine amino acids was established and sequentially screened using serum immunogloblin G obtained from CD patients.

RESULTS

Five different CD specific peptides were isolated from the phage library. No homology in amino acid sequences was observed among four (CDP-1, -3 to -5) of the five peptides exhibiting different binding characteristics with each CD patient's serum. In contrast, two peptides (CDP-1 and -2) had similar amino acid sequences and similar binding characteristics. Four multiple antigenic peptides (MAP, CDP-1, -3 to -5) were synthesised, and an enzyme linked immunosorbent assay (ELISA) using the four peptides was developed to detect serum antibodies against them. Fifty two of 92 CD patients (56.5%) were detected by ELISA, none of 20 ulcerative colitis (UC) patients, only one of 25 duodenal ulcer patients, and only three of 48 healthy subjects.

CONCLUSIONS

ELISA using the four peptides isolated in this study may be useful for the differential diagnosis of CD and UC.

Safety and efficacy of intravenous pulse cyclophosphamide in acute steroid refractory inflammatory bowel disease

BACKGROUND AND AIMS

One major problem in the management of steroid refractory attacks of patients with inflammatory bowel disease (IBD) is the establishment of a rapidly acting immunosuppressive regimen. Based on its well known efficacy in systemic vasculitis, intravenous cyclophosphamide pulse therapy was used in refractory IBD patients to evaluate both its efficacy and safety.

METHODS

Between December 1998 and May 2001, seven patients (Crohn's disease, n=5; indeterminate colitis, n=1) with severe steroid refractory IBD (Crohn's disease activity index (CDAI) 264-479 points) received 4-6 cycles of monthly treatment with intravenous cyclophosphamide (750 mg) in a prospective uncontrolled pilot study.

RESULTS

All patients improved after two intravenous pulses of cyclophosphamide and six of seven patients achieved complete remission (CDAI <150 points). One patient with Crohn's disease of the small and large bowel showed an impressive clinical response but did not enter into remission. Tapering to low dose steroids was possible in all responders. Remission was maintained in all patients for 18 months (median) but required a second course of intravenous pulse cyclophosphamide in one patient. The drug was well tolerated except for two episodes of candida oesophagitis.

CONCLUSIONS

Intravenous pulse cyclophosphamide may be a safe and effective treatment in patients with severe IBD unresponsive to steroid treatment and merits evaluation in a controlled trial.

Insurance problems among inflammatory bowel disease patients: results of a Dutch population based study

BACKGROUND AND AIMS

The majority of patients with inflammatory bowel disease (IBD) have a normal life expectancy and therefore should not be weighted when applying for life assurance. There is scant literature on this topic. In this study our aim was to document and compare the incidence of difficulties in application for life and medical insurance in a population based cohort of IBD patients and matched population controls.

METHODS

A population based case control study of 1126 IBD patients and 1723 controls. Based on a detailed questionnaire, the frequency and type of difficulties encountered when applying for life and medical insurance in matched IBD and control populations were appraised.

RESULTS

In comparison with controls, IBD patients had an 87-fold increased risk of encountering difficulties when applying for life assurance (odds ratio (OR) 87 (95% confidence interval (CI) 31-246)), with a heavily weighted premium being the most common problem. Patients of high educational status, with continuous disease activity, and who smoked had the highest odds of encountering such problems. Medical insurance difficulties were fivefold more common in IBD patients compared with controls (OR 5.4 (95% CI 2.3-13)) although no specific disease or patient characteristics were identified as associated with such difficulties.

CONCLUSIONS

This is the first detailed case control study that has investigated insurance difficulties among IBD patients. Acquiring life and medical insurance constituted a major problem for IBD patients in this study. These results are likely to be more widely representative given that most insurance companies use international guidelines for risk assessment. In view of the recent advances in therapy and promising survival data on IBD patients, evidence based guidelines for risk assessment of IBD patients by insurance companies should be drawn up to prevent possible discriminatory practices.

Signal transducer and activator of transcription 6 gene G2964A polymorphism and inflammatory bowel disease

Signal transducer and activator of transcription 6 (STAT6) is a key transcription factor involved in interleukin 4 (IL-4) and IL-13-mediated Th2 response. The STAT6 gene is located on chromosome 12q13.3-14.1 (IBD2 region) and is therefore a positional and functional candidate gene for study in inflammatory bowel disease. We investigated the G2964A polymorphism in the 3' untranslated region of the STAT6 gene in Dutch patients with inflammatory bowel disease and healthy controls. The G2964A polymorphism in the STAT6 gene was genotyped in 141 unrelated Dutch Caucasian patients with ulcerative colitis, 183 patients with Crohn's disease and 173 healthy individuals by PCR and the amplification-created restriction site method. Patients with Crohn's disease were classified according to the Vienna classification and the patients with ulcerative colitis were classified with the age at onset, extent of disease and colectomy. We did not find significant differences in genotype and allele frequencies of the G2964A polymorphism in the STAT6 gene between ulcerative colitis, Crohn's disease and healthy controls. Subgroups of the patients with Crohn's disease classified according to the Vienna classification and those with ulcerative colitis classified according to age of onset, disease extension and colectomy did not differ in the distribution of this polymorphism. The STAT6 G2964A gene polymorphism is not involved in the overall susceptibility or in determining the phenotype of IBD.

Birth outcome in women exposed to 5-aminosalicylic acid during pregnancy: a Danish cohort study

BACKGROUND

5-Aminosalicylic acid (5-ASA) preparations are the firstline drugs in the treatment of inflammatory bowel disease. Data on the safety of these drugs in pregnancy are sparse.

AIMS

To examine the risk of adverse birth outcome in women who were prescribed 5-ASA drugs during pregnancy.

PATIENTS

Women were included in the study if they were prescribed 5-ASA drugs immediately before or during pregnancy. To examine the risk of malformations, we included 60 pregnancies exposed to 5-ASA drugs 30 days before pregnancy or in the first trimester. To examine stillbirths, preterm births, and low birth weight, we included 88 pregnancies exposed during the entire pregnancy. Outcomes were compared with those of 19 418 pregnancies in which no drugs were prescribed for mothers during the study period.

METHODS

We conducted a Danish cohort study based on data from a population based prescription registry, the Danish Birth Registry, and the Hospital Discharge Registry in North Jutland County.

RESULTS

Odds ratios for malformations, stillbirth, preterm birth, and low birth weight in women who received prescriptions for 5-ASA drugs were 1.9 (95% confidence interval 0.7-5.4), 6.4 (1.7-24.9), 1.9 (0.9-3.9), and 1.2 (0.4-3.3), respectively. The increased risk of stillbirth and preterm birth were found only in patients with ulcerative colitis.

CONCLUSIONS

We found an increased risk of stillbirth and preterm birth in women who had been prescribed 5-ASA drugs during pregnancy but no substantial increased risk of malformations. It was difficult to distinguish the specific effects of disease activity and 5-ASA drugs.