The relationship between extreme inter-individual variation in macrophage gene expression and genetic susceptibility to inflammatory bowel disease

The differentiation of resident intestinal macrophages from blood monocytes depends upon signals from the macrophage colony-stimulating factor receptor (CSF1R). Analysis of genome-wide association studies (GWAS) indicates that dysregulation of macrophage differentiation and response to microorganisms contributes to susceptibility to chronic inflammatory bowel disease (IBD). Here, we analyzed transcriptomic variation in monocyte-derived macrophages (MDM) from affected and unaffected sib pairs/trios from 22 IBD families and 6 healthy controls. Transcriptional network analysis of the data revealed no overall or inter-sib distinction between affected and unaffected individuals in basal gene expression or the temporal response to lipopolysaccharide (LPS). However, the basal or LPS-inducible expression of individual genes varied independently by as much as 100-fold between subjects. Extreme independent variation in the expression of pairs of HLA-associated transcripts (HLA-B/C, HLA-A/F and HLA-DRB1/DRB5) in macrophages was associated with HLA genotype. Correlation analysis indicated the downstream impacts of variation in the immediate early response to LPS. For example, variation in early expression of IL1B was significantly associated with local SNV genotype and with subsequent peak expression of target genes including IL23A, CXCL1, CXCL3, CXCL8 and NLRP3. Similarly, variation in early IFNB1 expression was correlated with subsequent expression of IFN target genes. Our results support the view that gene-specific dysregulation in macrophage adaptation to the intestinal milieu is associated with genetic susceptibility to IBD.

Comparative genomics and phenotypic studies to determine site-specificity of Escherichia coli in the lower gastrointestinal tract of humans

Escherichia coli (E. coli) is an important commensal in the human gut; however, it is unknown whether strains show site-specificity in the lower gut. To investigate this, we assessed genotypic and phenotypic differences in 37 clone pairs (two strains with very similar multiple locus variable-number-tandem-repeat analysis [MLVA] profiles) of E. coli isolated from mucosal biopsies of two different gut locations (terminal ileum and rectum). The clone pairs varied at the genomic level; single nucleotide polymorphisms (SNPs) were common, multiple nucleotide polymorphisms (MNPs) were observed but less common, and few indels (insertions and deletions) were detected. The variation was higher in clone pairs that are associated with non-human-associated sequence types (ST) compared to human-associated STs, such as ST95, ST131, and ST73. No gene(s) with non-synonymous mutations were found to be commonly associated with either the terminal ileum or the rectal strains. At the phenotypic level, we identified the metabolic signatures for some STs. Rectum strains of some STs showed consistently higher metabolic activity with particular carbon sources. Clone pairs belonging to specific STs showed distinct growth patterns under different pH conditions. Overall, this study showed that E. coli may exhibit genomic and phenotypic variability at different locations in the gut. Although genomics did not reveal significant information suggesting the site-specificity of strains, some phenotypic studies have suggested that strains may display site-specificity in the lower gut. These results provide insights into the nature and adaptation of E. coli in the lower gut of humans. To the best of our knowledge, no study has investigated or demonstrated the site-specificity of commensal E. coli in the human gut.

Quality of care in inflammatory bowel disease: actual health service experiences fall short of the standards

BACKGROUND

Quality of care in inflammatory bowel disease (IBD) has received much attention internationally; however, the available surveys focus on health professionals rather than patients.

AIMS

To assess the experiences of healthcare for people living with IBD against established Australian IBD Standards.

METHODS

An online cross-sectional survey was conducted with Australians ≥16 years old recruited via Crohn's & Colitis Australia membership, public and private clinics and the Royal Flying Doctor Service. Participants completed a questionnaire incorporating items addressing the Australian IBD Standards 2016, the Picker Patient Experience Questionnaire, IBD Control Survey and the Manitoba Index.

RESULTS

Complete data were provided by 731 respondents (71.5% female, median age 46 years, ranging from 16 to 84 years). While the majority (74.8%) were satisfied with their IBD healthcare, the care reported did not meet the Australian IBD Standards. Overall, 32.4% had access to IBD nurses, 30.9% to a dietician and 12% to a psychologist in their treating team. Participants managed by public IBD clinics were most likely to have access to an IBD nurse (83.7%), helpline (80.7%) and research trials (37%). One third of respondents reported waiting >14 days to see a specialist when their IBD flared. Participants received enough information, mostly from medical specialists (88.8%) and IBD nurses (79.4%). However, 51% wanted to be more involved in their healthcare.

CONCLUSIONS

These data show discordance between expectations of patients and national standards with current levels of service provision, which fail to deliver equitable and comprehensive IBD care.

Australia IBD Microbiome (AIM) Study: protocol for a multicentre longitudinal prospective cohort study

INTRODUCTION

Crohn's disease and ulcerative colitis are common chronic idiopathic inflammatory bowel diseases (IBD), which cause considerable morbidity. Although the precise mechanisms of disease remain unclear, evidence implicates a strong multidirectional interplay between diet, environmental factors, genetic determinants/immune perturbations and the gut microbiota. IBD can be brought into remission using a number of medications, which act by suppressing the immune response. However, none of the available medications address any of the underlying potential mechanisms. As we understand more about how the microbiota drives inflammation, much interest has focused on identifying microbial signals/triggers in the search for effective therapeutic targets. We describe the establishment of the Australian IBD Microbiota (AIM) Study, Australia's first longitudinal IBD bioresource, which will identify and correlate longitudinal microbial and metagenomics signals to disease activity as evaluated by validated clinical instruments, patient-reported surveys, as well as biomarkers. The AIM Study will also gather extensive demographic, clinical, lifestyle and dietary data known to influence microbial composition in order to generate a more complete understanding of the interplay between patients with IBD and their microbiota.

METHODS

The AIM Study is an Australian multicentre longitudinal prospective cohort study, which will enrol 1000 participants; 500 patients with IBD and 500 healthy controls over a 5-year period. Assessment occurs at 3 monthly intervals over a 24-month period. At each assessment oral and faecal samples are self-collected along with patient-reported outcome measures, with clinical data also collected at baseline, 12 and 24 months. Intestinal tissue will be sampled whenever a colonoscopy is performed. Dietary intake, general health and psychological state will be assessed using validated self-report questionnaires. Samples will undergo metagenomic, transcriptomic, proteomic, metabolomic and culturomic analyses. Omics data will be integrated with clinical data to identify predictive biomarkers of response to therapy, disease behaviour and environmental factors in patients with IBD.

ETHICS AND DISSEMINATION

Ethical approval for this study has been obtained from the South Eastern Sydney Local Health District Research Ethics Committee (HREC 2019/ETH11443). Findings will be reported at national and international gastroenterology meetings and published in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

ACTRN12619000911190.

Vedolizumab in combined immune checkpoint therapy-induced infliximab-refractory colitis in a patient with metastatic melanoma: A case report

BACKGROUND

Dual checkpoint inhibition improves response rates in treatment naïve patients with metastatic melanoma compared to monotherapy. However, it confers a higher rate of toxicity, including immune-related colitis. Steroids may not resolve symptoms in all cases. The use of vedolizumab, a humanized monoclonal antibody against α4β7 integrin has proven effective in cases refractory to standard treatment.

CASE SUMMARY

We report the case of a 27-year-old female with Stage IVd metastatic melanoma treated with ipilimumab and nivolumab. She developed severe colitis refractory to methylprednisolone, infliximab and mycophenolate mofetil but responded to vedolizumab.

CONCLUSION

This case report supports vedolizumab use in severe immune related colitis refractory to standard immunosuppression.

Psychological distress is highly prevalent in inflammatory bowel disease: A survey of psychological needs and attitudes

Background and Aim

Data on patient needs and access to psychological services in inflammatory bowel disease (IBD) are scarce. This study aimed to describe the levels of distress and the needs, attitudes, and access to psychological services for people within Australia against established Australian IBD Standards.

Methods

An online cross‐sectional survey was conducted with Australians ≥16 years old recruited via Crohn's & Colitis Australia membership, public and private clinics, and the Royal Flying Doctor Service. K10 was used to measure psychological distress. The Chi‐square test was used to compare those with and without distress on key variables.

Results

Overall, 731 respondents provided complete data (71.5% female, mean age 46.5 years). Overall, 50% of respondents reported distress; only 15.2% were currently seeing a mental health practitioner; only 16.1% were asked about their mental health by their IBD specialist or IBD nurse; and only 12.2% reported access to a mental health practitioner as part of their IBD service. Those with psychological distress were significantly less satisfied with their IBD care; more commonly hospitalized; had an active disease, fistula or perianal disease, pain, or fatigue; and were receiving steroids, opioids, or antidepressants (all P < 0.05). As many as 68.2% of those with severe distress were not seeing a mental health practitioner.

Conclusions

The integrated biopsychosocial model of health care, with regular mental health screening and good access to mental health professionals, is requested by people living with IBD to improve their outcomes.

Inflammatory bowel disease-related fatigue is correlated with depression and gender

OBJECTIVES

Fatigue is a common and disabling problem in inflammatory bowel disease. We sought to explore the possible determinants of inflammatory bowel disease-associated fatigue including demographic, psychological and disease variables.

METHODS

Surveys were distributed to 100 patients undergoing infliximab infusion for inflammatory bowel disease in an infusion lounge, assessing attachment style (Experiences in Close Relationships Revised scale), fatigue (Functional Assessment of Chronic Illness Therapy Fatigue - Fatigue Subscore), and depression and anxiety (Hospital Anxiety and Depression Scale). Disease severity was assessed via file review through an independent gastroenterologist rating (Harvey-Bradshaw Index).

RESULTS

There were 67 responses. Depression, as measured by the Hospital Anxiety and Depression Scale, was found to be highly correlated with fatigue (Functional Assessment of Chronic Illness Therapy Fatigue - Fatigue Subscore). Anxiety, insecure attachment, disease severity and female gender were moderately correlated with fatigue. In a hierarchical regression model, depression and female gender emerged as significant predictors of variance in fatigue scores.

CONCLUSIONS

Depression was the strongest predictor of variance in fatigue scores. Gender as a cause of fatigue in inflammatory bowel disease requires further exploration. Attachment style, however, may still help clinicians to conceptualise help-seeking behaviour and clinician-patient relationships in medically unexplained symptoms.

Prevalence of Yersinia Species in the Ileum of Crohn's Disease Patients and Controls

Yersinia are common contaminants of food products, but their prevalence in the human gut is poorly documented. Yersinia have been implicated in Crohn's Disease (CD, an inflammatory bowel disease) however their role in CD is controversial. We performed highly sensitive PCR assays of specific sequences for the gyrB gene of Y. aldovae, Y. bercovieri, Y. enterocolitica, Y. intermedia, Y. mollaretii and the inv gene of Y. pseudotuberculosis. We analyzed a total of 470 ileal samples taken from 338 participants (262 CD patients and 76 controls) belonging to three independent cohorts. All patients and controls were phenotyped and genotyped for the main CD susceptibility variants: NOD2, ATG16L1, and IRGM. Yersinia were found in 7.7% of ileal samples (respectively 7.9 and 7.6% in controls and CD patients) corresponding to 10% of participants (respectively 11.8 and 9.5% in controls and CD patients). Y. enterocolitica, Y. pseudotuberculosis and Y. intermedia were the most frequently identified species. The bacteria were more frequent in resected specimens, lymph nodes and Peyer's patches. Yersinia were no more likely to be detected in CD tissues than tissues from inflammatory and non-inflammatory controls. CD patients treated with immunosuppressants were less likely to be Yersinia carriers. In conclusion, this work shows that Yersinia species are frequently found at low levels in the human ileum in health and disease. The role of Yersinia species in this ecosystem should now be explored.

The role of inflammation in temporal shifts in the inflammatory bowel disease mucosal microbiome

Studies of the human intestinal microbiome in patients with inflammatory bowel disease (IBD) consistently show that there are differences (an abnormal or unbalanced microbiome, "dysbiosis") when compared to healthy subjects. We sought to describe changes in the microbiome in individual patients over time, and determine the clinical factors that are associated with significant alteration. Forty-two mucosal biopsies were collected from 20 patients that were spaced an average of 2.4 years apart. These were analysed using bacterial 16S rRNA gene high-throughput sequencing methods. Presence of active inflammation was determined endoscopically and histologically. Inferred metagenomics analysis was conducted using the PICRUSt package. We found that the differences in the microbiome over time in individual patients were greatest in the presence of ongoing intestinal inflammation, as determined by the Yue and Clayton theta distance between sample pairs (adjusted p = 0.00031). Samples from patients with previous abdominal surgery had lower alpha (within sample) diversity compared with those with no prior operations (mean Shannon index 2.083, 2.510 respectively, p = 0.017). There were no changes in the inferred bacterial metagenomic profile. The microbiome in IBD undergoes considerable fluctuation over time. These changes are greatest when there is histologically confirmed inflammation at both time-points.

Genital Granulomatosis in Male and Female Patients With Crohn's Disease: Clinical Presentation and Treatment Outcomes

BACKGROUND

Genital granulomatosis [GG] is a metastatic form of Crohn's disease [CD], characterised by granulomatous inflammation of the genital skin without contact with the gastrointestinal tract. Little is known about GG, as most publications are case reports or small series, and only sporadic in male cases.

METHODS AND AIMS

Cases of GG were retrospectively collected through the Collaborative Network For Exceptionally Rare case reports project of the European Crohn's and Colitis Organisation.

RESULTS

A total of 43 patients [9 males, 34 females] were diagnosed as having GG, mostly as oedema and/or ulcers. Histological confirmation of granulomas was obtained in 70% of the cases. CD location was colonic or ileocolonic in 97% and perianal disease was documented in 57%. There was no significant difference between males and females in CD phenotype or genital lesions. GG was the first manifestation of inflammatory bowel disease [IBD] in one-third of the patients; these patients were younger at the time of GG occurrence and they all were non-smokers. GG occurred in the absence of gastrointestinal disease activity in 30% of the cases. Ten out of 11 patients [91%] responded to systemic corticosteroid treatment, 5/9 patients responded to immunomodulators, and 9/11 patients responded to anti-tumour necrosis factor alpha [TNF-α] agents.

CONCLUSIONS

GG is a rare extraintestinal manifestation of CD. It mainly occurs among women, in the setting of colonic involvement of CD, and perianal disease is often associated. Most cases are successfully managed with systemic corticosteroids or anti-TNF agents.

Within-host evolution versus immigration as a determinant of Escherichia coli diversity in the human gastrointestinal tract

When a human host harbors two or more strains of Escherichia coli, the second strain is more likely to be a member of the same phylogroup rather than a different phylogroup. This outcome may be the consequence of a within host evolution event or an independent immigration/establishment event. To determine the relative importance of these two events in determining E. coli diversity in a host, a collection of multiple E. coli isolates recovered from each of 67 patients undergoing colonoscopies was used. Whole genome sequence data were available for one example of every REP-fingerprint type identified in a patient. Sequence type (ST) and single-nucleotide polymorphism (SNP) analyses revealed that 83% of strains observed in the host population were a consequence of immigration/establishment events. Restricting the analysis to hosts harboring two or more strains belonging to the same phylogroup revealed that in about half of these cases, the presence of a second strain belonging to the same phylogroup was the consequence of an independent immigration/establishment event. Thus, the results of this study show that despite hosts being exposed to a diversity of E. coli via their food, factors related to the host also determine what E. coli strains succeed in establishing.

Comparative genomics of Crohn's disease-associated adherent-invasive Escherichia coli

OBJECTIVE

Adherent-invasive Escherichia coli (AIEC) are a leading candidate bacterial trigger for Crohn's disease (CD). The AIEC pathovar is defined by in vitro cell-line assays examining specific bacteria/cell interactions. No molecular marker exists for their identification. Our aim was to identify a molecular property common to the AIEC phenotype.

DESIGN

41 B2 phylogroup E. coli strains were isolated from 36 Australian subjects: 19 patients with IBD and 17 without. Adherence/invasion assays were conducted using the I-407 epithelial cell line and survival/replication assays using the THP-1 macrophage cell line. Cytokine secretion tumour necrosis factor ((TNF)-α, interleukin (IL) 6, IL-8 and IL-10) was measured using ELISA. The genomes were assembled and annotated, and cluster analysis performed using CD-HIT. The resulting matrices were analysed to identify genes unique/more frequent in AIEC strains compared with non-AIEC strains. Base composition differences and clustered regularly interspaced palindromic repeat (CRISPR) analyses were conducted.

RESULTS

Of all B2 phylogroup strains assessed, 79% could survive and replicate in macrophages. Among them, 11/41 strains (5 CD, 2 UCs, 5 non-IBD) also adhere to and invade epithelial cells, a phenotype assigning them to the AIEC pathovar. The AIEC strains were phylogenetically heterogeneous. We did not identify a gene (or nucleic acid base composition differences) common to all, or the majority of, AIEC. Cytokine secretion and CRISPRs were not associated with the AIEC phenotype.

CONCLUSIONS

Comparative genomic analysis of AIEC and non-AIEC strains did not identify a molecular property exclusive to the AIEC phenotype. We recommend a broader approach to the identification of the bacteria-host interactions that are important in the pathogenesis of Crohn's disease.

Escherichia coli diversity in the lower intestinal tract of humans

Previous studies examining the clonal diversity of Escherichia coli populations within humans have been based on faecal isolates. In this study E. coli were isolated from biopsies taken from the terminal ileum, ascending, transverse and descending colon, and rectum of 69 individuals. Multiple isolates from each biopsy were characterized using Rep-PCR. An average of 3.5 genotypes were recovered per host, and in hosts with two or more strains, the phylogroup membership of the second most abundant strain was significantly more likely to be the same as the dominant strain. There was no indication of a non-random distribution of E. coli phylogroups among the regions of the lower intestine. In hosts with multiple genotypes, as defined by Repetitive extragenic palindromic-PCR, genotypes were non-randomly distributed among gut regions in over half the individuals. The phylogroup membership of an individual's numerically dominant strain explained some of the variation in the extent to which strains within an individual were heterogeneously distributed, with most heterogeneity observed when the numerically dominant strain belonged to phylogroups E or F, and the least when the dominant strain belonged to phylogroup B2. The results of this study support previous studies on pigs that demonstrated faecal sampling underestimates the genotype diversity present within a host.

Gut feelings 1. Mind, mood and gut in irritable bowel syndrome: approaches to psychiatric care

OBJECTIVE

Psychiatrists are likely to encounter patients with irritable bowel syndrome (IBS). We aim to provide a clinically-focused summary of psychiatric comorbidities and management.

CONCLUSIONS

IBS affects up to 15% of the population. Antidepressants and brief psychotherapy can reduce symptom severity and improve coping. These treatments are effective for patients without comorbid mental illness, as well as those with increased somatisation, health-care seeking and sexual abuse histories.

Gut feelings 2. Mind, mood and gut in inflammatory bowel disease: approaches to psychiatric care

OBJECTIVES

The authors aim to provide a clinically-focused summary of psychiatric complications of inflammatory bowel disease (IBD), and give treatment recommendations.A narrative review of literature drawn from PubMed and Medline.

CONCLUSIONS

IBD is a chronic, debilitating and potentially body integrity altering condition with significant morbidity and a slight increase in mortality. Co-morbidity with anxiety and depression is common. Onset in the younger years can disturb development. Psychotherapy may be most useful for addressing fatigue, pain and assisting with coping. There is a lack of evidence to guide treatment of depression in this population.

Infliximab reverses inflammatory muscle wasting (sarcopenia) in Crohn's disease

BACKGROUND

Muscle wasting or sarcopenia arising from chronic inflammation is found in 60% of patients with Crohn's disease. Transcriptional protein NF-κB reduces muscle formation through MyoD transcription and increases muscle breakdown by proteolysis.

AIM

As TNF is a potent activator of NF-κB, and anti-TNF agent infliximab (IFX) prevents NF-κB activation, to determine whether or not Crohn's patients treated with IFX gain muscle volume and strength.

METHODS

We performed a prospective, repeated-measures cohort study in adult Crohn's disease patients with an acute disease flare. Patients were instructed not to vary diet or activity. Concomitant medications were kept stable. At week 1 (pre-treatment), week 16 (post-IFX induction) and week 25 (post-first IFX maintenance dose), we assessed (i) MRI volume of quadriceps femoris at anatomical mid-thigh; (ii) maximal concentric quadriceps contractions strength at three specific speeds of contraction; (iii) physical activity by validated instrument (IPAQ); (iv) Three-day food record of intake and composition (food-weighing method); (v) Serum levels of IL6.

RESULTS

Nineteen patients (58% female; mean age 33.2 ± 10.7 years) were recruited. IFX increased muscle volume in both legs from baseline (right, 1505 cm(3) ) to week 25 (right, 1569 cm(3) ; P = 0.010). IFX also increased muscle strength in both legs from baseline (right 30°/s, 184.8 Nm) to week 25 (right 30°/s, 213.6 Nm; P = 0.002). Muscle volume gain correlated with male gender (P = 0.003). Significant gains in muscle volume and strength were unrelated to prednisolone use. Serum IL6 levels decreased by week 25 (P = 0.037).

CONCLUSION

The anti-TNF agent infliximab reverses inflammatory sarcopenia in patients with Crohn's disease.

Hepatosplenic T-cell lymphoma, immunosuppressive agents and biologicals: what are the risks?

We present three cases of the rare hepatosplenic T-cell lymphoma (HSTCL); two patients suffering from Crohn disease who developed HSTCL on azathioprine without exposure to biologicals, and a third patient who had psoriasis treated using etanercept, cyclosporine and methotrexate. The evidence for an association between HSTCL and immunosuppressive drugs and biologicals is reviewed. We argue for improved pharmacovigilance processes to help determine the benefit to risk ratios for the use of these and other new agents.

Detection of bacterial DNA in lymph nodes of Crohn's disease patients using high throughput sequencing

OBJECTIVE

Our aim was to determine whether or not specific microorganisms were transported selectively to lymph nodes in Crohn's disease (CD) by comparing node and mucosal microbial communities in patients and controls. We also sought evidence of dysbiosis and bacterial translocation.

DESIGN

Lymph nodes, and involved and uninvolved mucosal samples were obtained from resections of 58 patients (29 CD, eight 'other inflammatory bowel disease' (IBD) and 21 non-IBD). Universal primers targeting V1-V3 regions of bacterial 16S rRNA genes were used to amplify bacterial DNA and amplicons sequenced using high throughput sequencing. 20 patients (eight CD (28%), two other IBD (25%) and 10 non-IBD (48%)) had PCR positive nodes.

RESULTS

All samples from an individual were similar: there was no evidence of selective concentration of any microorganism in nodes. No specific microorganism was present in the nodes of all CD samples. Escherichia/Shigella were common in all patient groups but patients with ileal CD had a greater proportion of Escherichia coli reads in their nodes than other CD patients (p=0.0475). Campylobacter, Helicobacter and Yersinia were uncommon; Mycobacterium and Listeria were not detected. Dysbiosis was present in all groups but shifts were specific and no common pattern emerged.

CONCLUSIONS

It is unlikely that a single bacterium perpetuates inflammation in late stage CD; dysbiosis was common and we found no evidence of increased bacterial translocation. We believe that future studies should focus on early disease and viable bacteria in nodes, aphthous ulcers and granulomas, as they may be more relevant in the initiation of inflammation in CD.

Two rare cases of Epstein-Barr virus-associated lymphoproliferative disorders in inflammatory bowel disease patients on thiopurines and other immunosuppressive medications

The setting of chronic immunosuppression in inflammatory bowel disease (IBD) may promote the proliferation of Epstein-Barr virus-positive neoplastic clones. We report two rare cases of Epstein-Barr virus-associated lymphoproliferative disorder in IBD patients: one resembled lymphomatoid granulomatosis, and the other was a lymphoma resembling Hodgkin lymphoma. There are currently no guidelines for the prevention of lymphoproliferative disorder in IBD patients on immunosuppressive therapy.

Impact of colonoscopy bowel preparation on intestinal microbiota

The gut microbiota is important in maintaining human health, but numerous factors have the potential to alter its composition. Our aim was to examine the impact of a standard bowel preparation on the intestinal microbiota using two different techniques. Fifteen subjects undergoing colonoscopy consumed a bowel preparation comprised of 10 mg bisacodyl and 2 L polyethylene glycol. The microbiota of stool samples, collected one month before, one week before (pre-colonoscopy), and one week, one month, and three to six months after colonoscopy (post-colonoscopy) was evaluated. Two samples were taken three to six months apart from five healthy subjects who did not undergo colonoscopy. Universal primers targeting the V2-V3 region of the 16S rRNA gene were used to PCR amplify all samples for denaturing gradient gel electrophoresis (PCR-DGGE). Pre- and post-colonoscopy samples were compared using Dice's similarity coefficients. Three samples from ten subjects who underwent colonoscopy, and both samples from the five subjects who didn't, were used for high-throughput sequencing of the V1-V3 region of the 16S rRNA gene. Samples were curated and analysed in Mothur. Results of the DGGE analyses show that the fecal microbiota of a small number of subjects had short-term changes. High-throughput sequencing results indicated that the variation between the samples of subjects who underwent colonoscopy was no greater than the variation observed between samples from subjects who did not. We conclude that bowel preparation does not have a lasting effect on the composition of the intestinal microbiota for the majority of subjects.

Glatiramer acetate induced hepatotoxicity

INTRODUCTION

Glatiramer acetate (Copaxone), a polypeptide has been approved for treating patients with active relapsing-remitting multiple sclerosis.

CASE PRESENTATION

We report the first case of severe acute hepatitis after commencing treatment for multiple sclerosis with glatiramer acetate. A 31-year-old female with multiple sclerosis presented with anorexia, lethargy and jaundice five weeks after commencing glatiramer acetate. She had never received beta-interferon treatment. Investigations revealed a bilirubin of 0.109 mmol/L (0.002-0.02 mmoL/L) and prothrombin time of 21 secs (9-15 secs). Her liver function tests were normal before commencing glatiramer acetate. A liver biopsy performed approximately 6 weeks after commencement of glatiramer acetate showed predominantly centrilobular hepatocyte necrosis with portal-venous bridging, along with mild portal and interface hepatitis. The necrosis was not accompanied by an acute inflammatory or chronic inflammatory infiltrate. The features were not suggestive of autoimmune hepatitis but consistent with drug toxicity. The liver tests returned to normal within 2 months after cessation of glatiramer acetate.

CONCLUSION

Physicians should be aware that glatiramer acetate can be associated with uncommon but yet significantly severe liver toxicity.

Lymphoma and other lymphoproliferative disorders in inflammatory bowel disease: a review

The lymphoproliferative disorders (LDs) are a heterogeneous group of at least 70 conditions that result from the clonal proliferation of B, T, and NK cells. Inflammatory bowel disease (IBD)-associated lymphomas are typically B-cell LD, while T-cell or Hodgkin's lymphomas are rare. In IBD patients not on immunosuppression, the risk of LD seems to be similar or slightly higher than the background population risk. Thiopurine therapy is associated with an increased risk: the relative risk is increased four- to sixfold and the absolute risk varies between 1 in 4000-5000 for those aged 20-29 to 1 in 300-400 in those over 70. It is difficult to quantify the risk of anti- tumor necrosis factor (TNF) therapy alone; however, it appears to be less than for thiopurines alone. There is particular concern regarding the development of post-transplant-like LD in those with latent epstein-barr virus (EBV) infection exposed to immunosuppressives, the occurrence of hepatosplenic T cell lymphoma in patients treated with combination anti-TNF and thiopurine therapy, and the development of hemophagocytic lymphohistiocytosis in those who acquire a primary EBV or other infections while on immunosuppressive medication. There are currently no guidelines for monitoring EBV (or other virus) status in patients on immunosuppression, although it could be used to monitor those who have a prior history of lymphoma and are about to start a thiopurine or anti-TNF agent. In discussing the risks of lymphoproliferative disorders associated with agents used for the treatment of IBD, patients can often be reassured that the benefits of such therapy still outweigh the small, but real, risks.

Effects of bacterial products on enterocyte-macrophage interactions in vitro

We describe a coculture model of a human intestinal epithelial cell line and human peripheral blood monocytes in which monocytes differentiate into cells with features of resident intestinal macrophages. Caco-2 cells are grown on the lower surface of a semipermeable filter with pore size of 3 μm (Transwells) until they differentiate into enterocytes. Peripheral-blood monocytes are added and the co-culture incubated for two days. Monocytes migrate through the pores of the membrane, come into direct contact with the basolateral surfaces of the epithelial cell monolayer, and develop characteristics of resident intestinal macrophages including downregulation of CD14 expression and reduced pro-inflammatory cytokine responses (IL-8, TNF and IL-1β) to bacterial products. The apical application of lipopolysaccharide (LPS) and muramyl dipeptide (MDP) resulted in an increased number of integrated monocytes, but abrogated the downregulation of CD14 expression and the diminished cytokine responses. MDP also reduced tight-junctional integrity, whilst LPS had no effect. These data indicate that LPS and MDP have significant pathophysiological effects on enterocyte-monocyte interactions, and confirm other studies that demonstrate that enterocytes and their products influence monocyte differentiation. This model may be useful in providing insights into the interaction between monocytes, epithelial cells and intestinal bacteria in health and disease.

Advances in the management of inflammatory bowel disease

Our understanding of inflammatory bowel diseases (IBD) is constantly evolving, and many new treatment options have emerged recently. This review critically examines the evidence for these new developments and aims to provide an overview for medical professionals involved in the care of patients with IBD. Proposed changes in the use of aminosalicylates, immunosuppressants and biological agents are described, and the evidence for several promising novel agents is reviewed.

Rational investigation of upper abdominal pain

BACKGROUND

Upper abdominal pain is a common problem with an extraordinary diversity of possible causes. Many patients have no structural disease, and making the correct diagnosis can be a challenge. The roles of endoscopy, testing for Helicobacter pylori, and imaging techniques have been debated widely and continue to be a matter for discussion.

OBJECTIVE

This article details the value of various investigations in the setting of specific presentations of upper abdominal pain.

DISCUSSION

Functional dyspepsia is a common cause of upper abdominal pain but the diagnosis should only be made after consideration of more serious pathology. The various organic causes of upper abdominal pain and the appropriate investigations are discussed. Early endoscopy is advisable in the presence of alarm symptoms and in patients over 55 years of age.

Aspiration in the context of upper gastrointestinal endoscopy

BACKGROUND

Pulmonary aspiration is a life-threatening complication of upper gastrointestinal endoscopy, the incidence of which has not been determined. Endoscopy-related aspiration has not been studied in procedures in which patients swallow a radiolabelled potential aspirate immediately before endoscopy and undergo nuclear scanning postprocedure.

METHODS

A pilot study was conducted in which 200 MBq of nonabsorbable technetium-99m phytate in 10 mL of water was administered orally to 50 patients who were about to undergo endoscopy. Gamma camera images were obtained to ensure that there had been no aspiration before endoscopy. After endoscopy, a repeat scan was performed. Fluid aspirated through the endoscope was also collected and analyzed for radioactivity using a hand-held radiation monitor.

RESULTS

No evidence of pulmonary aspiration was found in any of the patients studied. The mean estimated percentage of the initially administered radioactivity aspirated through the endoscope was 2.66% (range 0% to 10.3%).

CONCLUSION

The present pilot study confirms earlier observations that clinically significant aspiration in the context of upper gastrointestinal endoscopy is uncommon. The incidence of aspiration may, however, be different in acutely bleeding patients undergoing endoscopy. For logistic reasons, this group could not be studied.

Two-year combination antibiotic therapy with clarithromycin, rifabutin, and clofazimine for Crohn's disease

BACKGROUND & AIMS

Mycobacterium avium subspecies paratuberculosis has been proposed as a cause of Crohn's disease. We report a prospective, parallel, placebo-controlled, double-blind, randomized trial of 2 years of clarithromycin, rifabutin, and clofazimine in active Crohn's disease, with a further year of follow-up.

METHODS

Two hundred thirteen patients were randomized to clarithromycin 750 mg/day, rifabutin 450 mg/day, clofazimine 50 mg/day or placebo, in addition to a 16-week tapering course of prednisolone. Those in remission (Crohn's Disease Activity Index <or=150) at week 16 continued their study medications in the maintenance phase of the trial. Primary end points were the proportion of patients experiencing at least 1 relapse at 12, 24, and 36 months.

RESULTS

At week 16, there were significantly more subjects in remission in the antibiotic arm (66%) than the placebo arm (50%; P=.02). Of 122 subjects entering the maintenance phase, 39% taking antibiotics experienced at least 1 relapse between weeks 16 and 52, compared with 56% taking placebo (P=.054). At week 104, the figures were 26% and 43%, respectively (P=.14). During the following year, 59% of the antibiotic group and 50% of the placebo group relapsed (P=.54).

CONCLUSIONS

Using combination antibiotic therapy with clarithromycin, rifabutin, and clofazimine for up to 2 years, we did not find evidence of a sustained benefit. This finding does not support a significant role for Mycobacterium avium subspecies paratuberculosis in the pathogenesis of Crohn's disease in the majority of patients. Short-term improvement was seen when this combination was added to corticosteroids, most likely because of nonspecific antibacterial effects.

What may underlie recurrent purpura fulminans?

A woman presenting with recurrent purpura fulminans was eventually found to have inflammatory bowel disease. We suggest the inflammatory state resulted in a deficiency of functional protein C.

Perioperative acute upper gastrointestinal haemorrhage in older patients with hip fracture: incidence, risk factors and prevention

BACKGROUND

No specific preventive strategy exists for acute gastrointestinal haemorrhage in hip fracture patients.

AIMS

To determine the effectiveness of prophylactic use of proton pump inhibitors in patients with risk factors for acute gastrointestinal haemorrhage.

METHODS

Prospective two-stage study of 822 consecutive older (> or =60 years) hip fracture patients.

RESULTS

Acute gastrointestinal haemorrhage occurred in 16 (3.9%) of 407 patients and was associated with increased length of hospital stay (28.7 vs. 15.9; P = 0.0027) and mortality (18.8% vs. 4.3%; P = 0.043). Multiple analysis identified five independent risk factors for acute gastrointestinal haemorrhage: pre-existing peptic ulcer (OR 4.3; P = 0.043), current smoking (OR 3.1; P = 0.023), post-operative use of an antiplatelet agent (OR 6.5; P = 0.046), post-operative use of non-steroidal anti-inflammatory drug/cyclo-oxygenase-2 inhibitor (OR 4.9; P = 0.06) and blood group O (OR 1.7; P = 0.046). These risk factors were highly sensitive and had a negative predictive value of 99.8%. Prophylactic use of proton pump inhibitors in patients with risk factor for acute gastrointestinal haemorrhage significantly reduced the incidence of this complication (0.72% in treated patients vs. 13.4% in untreated; P < 0.001); the number needed to treat was 7.9. Conclusions In older hip fracture patients perioperative acute gastrointestinal haemorrhage occurs in 3.9% and is associated with poor outcome. Preventive proton pump inhibitor therapy in patients at risk of acute gastrointestinal haemorrhage is effective and safe.

The IBD international genetics consortium provides further evidence for linkage to IBD4 and shows gene-environment interaction

BACKGROUND AND AIMS

The inflammatory bowel diseases (IBDs) Crohn's disease (CD) and ulcerative colitis are complex disorders with an important genetic determinant. One gene associated with CD has been identified: NOD2/CARD15. Two independent genome-wide scans found significant evidence (logarithm of odds [LOD] 3.6) and suggestive evidence (LOD 2.8) for linkage on locus 14q11-12, also known as the IBD4 locus. To further characterize this locus, we assessed gene-environment interaction (IBD4 x smoking) and phenotypic heterogeneity in a large cohort of IBD-affected sibling pairs as part of an ongoing international collaborative effort.

PATIENTS AND METHODS

A total of 733 IBD families, comprising 892 affected sibling pairs, were genotyped for microsatellites D14S261, D14S283, D14S972, and D14S275, spanning the IBD4 locus. Information on gender, ethnicity, age at onset, smoking at diagnosis, extraintestinal manifestations, and disease location was available.

RESULTS

A significant distortion in the mean allele sharing (MAS) between affected siblings was observed for CD patients only at each of the four markers (54.6%, 52.8%, 50.4%, and 53.3%, respectively). Maximum linkage for CD was observed at marker D14S261 (multipoint nonparametric linkage score 2.36; P </= 0.01; MAS 54.6%). MAS was higher in CD families in which all siblings or at least one sibling smoked compared with nonsmoking CD families (MAS, 58.90%, 57.50%, and 52.80%, respectively).

CONCLUSIONS

The IBD International Genetics Consortium replicated the IBD4 locus on chromosome 14q for CD and also showed evidence for a gene-environment interaction at this locus. Further studies are needed to explore the mechanism by which smoking influences IBD4.

A macrophage colony-stimulating factor receptor-green fluorescent protein transgene is expressed throughout the mononuclear phagocyte system of the mouse

The c-fms gene encodes the receptor for macrophage colony-stimulating factor (CSF-1). The gene is expressed selectively in the macrophage and trophoblast cell lineages. Previous studies have indicated that sequences in intron 2 control transcript elongation in tissue-specific and regulated expression of c-fms. In humans, an alternative promoter was implicated in expression of the gene in trophoblasts. We show that in mice, c-fms transcripts in trophoblasts initiate from multiple points within the 2-kilobase (kb) region flanking the first coding exon. A reporter gene construct containing 3.5 kb of 5' flanking sequence and the downstream intron 2 directed expression of enhanced green fluorescent protein (EGFP) to both trophoblasts and macrophages. EGFP was detected in trophoblasts from the earliest stage of implantation examined at embryonic day 7.5. During embryonic development, EGFP highlighted the large numbers of c-fms-positive macrophages, including those that originate from the yolk sac. In adult mice, EGFP location was consistent with known F4/80-positive macrophage populations, including Langerhans cells of the skin, and permitted convenient sorting of isolated tissue macrophages from disaggregated tissue. Expression of EGFP in transgenic mice was dependent on intron 2 as no lines with detectable EGFP expression were obtained where either all of intron 2 or a conserved enhancer element FIRE (the Fms intronic regulatory element) was removed. We have therefore defined the elements required to generate myeloid- and trophoblast-specific transgenes as well as a model system for the study of mononuclear phagocyte development and function.

CARD15/NOD2 risk alleles in the development of Crohn's disease in the Australian population

We have previously reported strong evidence for linkage between IBD1 and Crohn's disease (CD) in Australian Crohn's disease families. Three risk alleles for Crohn's disease, (Arg702Trp (C/T), Gly908Arg (G/C) and 980fs981 (-/C), were recently identified in the CARD15/NOD2 gene on chromosome 16, implicating this as the IBD1 locus. Using a novel diagnostic PCR-RFLP, we have examined the frequency of these alleles in 205 multiplex IBD families, 107 sporadic Crohn's disease cases and 409 normal individuals. We demonstrate that the three risk alleles are more frequent in Crohn's disease, than in controls, with allelic frequencies of 0.11, 0.02 and 0.07 respectively. Heterozygosity for individual variants conferred a three-fold increase in risk for Crohn's disease while substantially higher risks were associated with being homozygous or compound heterozygous. Despite a significantly lower population allele frequency for the frameshift mutation than reported by other groups, we see a similar contribution by this allele to the risk of developing Crohn's disease. While the three risk alleles influence susceptibility to Crohn's disease in Australia, we show that these alleles do not fully explain the linkage evidence and suggest that there are very likely additional IBD1 susceptibility alleles yet to be described in Australian CD at the NOD2 locus. We also show a second linkage peak in Australian CD that provides some support for a second disease susceptibility locus on chromosome 16.