Metabolomics Reveals Metabolic Biomarkers of Crohn's Disease

The causes and etiology of Crohn''s disease (CD) are currently unknown although both host genetics and environmental factors play a role. Here we used non-targeted metabolic profiling to determine the contribution of metabolites produced by the gut microbiota towards disease status of the host. Ion Cyclotron Resonance Fourier Transform Mass Spectrometry (ICR-FT/MS) was used to discern the masses of thousands of metabolites in fecal samples collected from 17 identical twin pairs, including healthy individuals and those with CD. Pathways with differentiating metabolites included those involved in the metabolism and or synthesis of amino acids, fatty acids, bile acids and arachidonic acid. Several metabolites were positively or negatively correlated to the disease phenotype and to specific microbes previously characterized in the same samples. Our data reveal novel differentiating metabolites for CD that may provide diagnostic biomarkers and/or monitoring tools as well as insight into potential targets for disease therapy and prevention.     

Effect of enterocoated cholestyramine on bowel habit after ileal resection: a double blind crossover study.

Ileal resection causes malabsorption of bile acid; the increased load of bile acids in the colon induces increased secretion of salt and water and hence diarrhoea. A study was carried out to test the effect of an enterocoated cholestyramine tablet designed to disintegrate in the colon and sequester the bile acids there, thereby minimising diarrhoea induced by bile acids while having no effect on malabsorption of bile acid and jejunal fat absorption. The study comprised 14 patients who had undergone ileal resection of 40-150 cm for Crohn''s disease. A double blind crossover trial was performed with placebo and cholestyramine enterocoated with cellulose acetate phthalate. During treatment with cholestyramine the daily faecal output decreased, the number of defecations each week decreased, and the intestinal transit time increased. Acceptability of the tablets was high, in contrast with general clinical experience with cholestyramine powder. No change was observed in the total faecal output of bile acids or fat. Cholestyramine tablets caused a reduction in diarrhoea without noticeably interfering with the metabolism of fat or bile acid.     

Crohn's disease of the appendix

Granulomatous inflammation typifying Crohn''s disease was centred within or confined to appendices in six patients, two of whom developed lesions attributable to Crohn''s disease elsewhere in the gut. The remaining four patients have remained symptom-free for periods varying from two to six years. Histological evidence of Crohn''s disease was also present in five of 46 appendices available for re-examination in a survey of 63 cases of Crohn''s enterocolitis. It is adduced that appendiceal involvement in Crohn''s disease is not uncommon.     

Effect of Crohn's disease mesenteric mesenchymal stem cells and their extracellular vesicles on T‐cell immunosuppressive capacity

Crohn''s disease (CD) is a chronic inflammatory disease of the gastrointestinal intestinal tract and has characteristic hypertrophic adipose changes observed in the mesentery. To better understand the role of the mesentery in the pathophysiology of Crohn''s disease (CD), we evaluated the immunomodulatory potential of mesenchymal stem cells (MSCs) and their secreted extracellular vesicles (EVs) derived from Crohn''s patients. MSCs and EVs were isolated from the mesentery and subcutaneous tissues of CD patients and healthy individuals subcutaneous tissues, and were analysed for differentiation, cytokine expression, self‐renewal and proliferation. The varying capacity of these tissue‐derived MSCs and EVs to attenuate T‐cell activation was measured in in vitro and an in vivo murine model. RNA sequencing of inflamed Crohn''s disease mesentery tissue revealed an enrichment of T‐cell activation compared to non‐inflamed subcutaneous tissue. MSCs and MSC‐derived EVs isolated from Crohn''s mesentery lose their ability to attenuate DSS‐induced colitis compared to subcutaneous tissue‐derived cell or EV therapy. We found that treatment with subcutaneous isolated MSCs and their EV product compared to Crohn''s mesentery MSCs or EVs, the inhibition of T‐cell proliferation and IFN‐γ, IL‐17a production increased, suggesting a non‐inflamed microenvironment allows for T‐cell inhibition by MSCs/EVs. Our results demonstrate that Crohn''s patient‐derived diseased mesentery tissue MSCs lose their immunosuppressive capacity in the treatment of colitis by distinct regulation of pathogenic T‐cell responses and/or T‐cell infiltration into the colon.     

Immunotherapy of Crohn's disease.

Although the initiating events of Crohn''s disease are unknown, models of experimental colitis have provided new insights in the immunologically mediated pathways of mucosal inflammation. In Crohn''s disease activated mucosal T lymphocytes produce proinflammatory cytokines within the mucosal compartment. With this understanding, there has been a shift in past years from the use of unspecific anti-inflammatory agents (corticosteroids, aminosalicylates) to the use of immunomodulatory drugs (azathioprine, methotrexate). Moreover, novel strategies have been designed for specific targets in Crohn''s disease, in particular T lymphocytes and cytokines. In an open label study treatment of steroid-refractory Crohn''s disease with anti- CD4+ antibodies was well tolerated and showed clinical benefit. However, a sustained depletion of the CD4+ cells precluded further clinical trials. In controlled clinical studies, anti-tumour necrosis factor (TNF-alpha) antibodies induced complete remissions and few side effects were observed. One study suggested efficacy in active Crohn''s disease of recombinant interleukin-10. Long term treatment studies will have to answer questions about the indications for use, benefit and toxicity. Altogether, these results hold promise for future management of Crohn''s disease, where disease-modifying interventions and strategies that effectively maintain disease remission will play a key role.     

In-vitro Inhibition of Leucocyte Migration in Crohn's Disease by a Sarcoid Spleen Suspension

A Kveim suspension has been shown to inhibit the migration of leucocytes in vitro from 12 out of 18 patients with Crohn''s disease but to have no comparable effect on leucocytes from patients with ulcerative colitis or from a group of patients with other diseases. These findings provide further evidence of cross-reactivity or of a possible aetiological link between Crohn''s disease and sarcoidosis and suggest a further immunological distinction between Crohn''s disease and ulcerative colitis.     

Elemental diet as primary treatment of acute Crohn's disease: a controlled trial.

Acute exacerbations of Crohn''s disease are usually treated with prednisolone or potentially more toxic immunosuppressive drugs or by surgery. In pilot studies replacing the normal diet by a protein free elemental diet also induced remission. A controlled trial was therefore conducted in which 21 patients acutely ill with exacerbations of Crohn''s disease were randomised to receive either prednisolone 0.75 mg/kg/day or an elemental diet (Vivonex) for four weeks. Assessment at four and 12 weeks showed that the patients treated with the elemental diet had improved as much as and by some criteria more than the steroid treated group. Elemental diet is a safe and effective treatment for acute Crohn''s disease.     

Crohn's Disease and Pregnancy

This paper reports the outcome of 60 pregnancies in 40 women, all of whom had concomitant Crohn''s disease. Detailed analysis of pregnancy rates in Crohn''s disease supports in outline the hypothesis that some patients with bowel symptoms may be rendered temporarily subfertile by the activity of their bowel complaints. In contrast there is little or no evidence of any adverse effect during pregnancy on mother or child. Most pregnancies went normally to term and, if anything, Crohn''s disease tended to improve during the period of confinement.After delivery, however, over 40% of patients suffered a relapse of Crohn''s disease. Such a situation might well constitute a logical indication for the administration of corticosteroid therapy.     

Prioritisation and Network Analysis of Crohn's Disease Susceptibility Genes

Recent Genome-Wide Association Studies (GWAS) have revealed numerous Crohn''s disease susceptibility genes and a key challenge now is in understanding how risk polymorphisms in associated genes might contribute to development of this disease. For a gene to contribute to disease phenotype, its risk variant will likely adversely communicate with a variety of other gene products to result in dysregulation of common signaling pathways. A vital challenge is to elucidate pathways of potentially greatest influence on pathological behaviour, in a manner recognizing how multiple relevant genes may yield integrative effect. In this work we apply mathematical analysis of networks involving the list of recently described Crohn''s susceptibility genes, to prioritise pathways in relation to their potential development of this disease. Prioritisation was performed by applying a text mining and a diffusion based method (GRAIL, GPEC). Prospective biological significance of the resulting prioritised list of proteins is highlighted by changes in their gene expression levels in Crohn''s patients intestinal tissue in comparison with healthy donors.     

The use of oral topically acting glucocorticosteroids in the treatment of inflammatory bowel disease.

Glucocorticosteroids are the mainstay of treatment of active Crohn''s disease and ulcerative colitis. These drugs however carry important cosmetic short-term side effects and when used long-term they induce severe irreversible complications. Topically acting glucocorticosteroids, especially budesonide, have been designed to achieve local effect at the site of inflammation without systemic effects of the drug. The first results of clinical trials are promising and budesonide has been shown to have an improved safety with almost comparable efficacy in comparison with prednisolone. The optimal enema dose seems to be 2 mg/100 ml at night whereas 9 mg o.m. is the optimal dose to treat ileal or right ileocolonic Crohn''s disease. Topically acting GCS, like standard GCS are not effective for maintenance of remission of Crohn''s disease or recurrence prevention after resection of the involved Crohn''s segment.     

Colonic Crohn's disease and use of oral contraception.

The prevalence of use of oral contraception before the onset of disease was established in 100 consecutive women attending follow up clinics for inflammatory bowel disease. A significant excess of women with Crohn''s disease confined to the colon had taken oral contraceptives in the year before developing symptoms (10/16 (63%] compared with women with small-intestinal Crohn''s disease (12/49 (24%); p less than 0.02) and women with ulcerative colitis (3/35 (9%); p less than 0.0005). When the patient groups were matched for age and year of onset of disease usage of oral contraception before the onset of disease was still more common among women with isolated colonic Crohn''s disease (9/12, 75%) than among those with ulcerative colitis (2/12 (17%); p less than 0.02) and was also more common than would be expected from reported figures for oral contraception in England and Wales (31.4% of women aged under 41; p less than 0.005). A survey of current patient records showed that isolated colonic disease was at least twice as common among women with Crohn''s disease (63/218, 29%) compared with men (25/181, 14%; p less than 0.001). These data support the suggestion made previously that oral contraceptives may predispose to a colitis that resembles colonic Crohn''s disease.     

Persistent Tn polyagglutination syndrome during febrile neutropenia: a case report and review of the literature

Introduction

Crohn's disease is a chronic inflammatory bowel disease of unknown etiology which may affect any part of the bowel. Fistulas are a common and often serious complication of Crohn's disease. The treatment for fistulizing Crohn's disease can be medical, surgical or a combination of the two. Recently, adalimumab, a fully human anti-tumor necrosis factor monoclonal antibody, has been suggested as a safe and effective treatment for the induction and maintenance of remission in adult patients with moderate to severe Crohn's disease, who are refractory to conventional therapy or intolerant to infliximab. However, large studies focusing on evaluating the efficacy of adalimumab in fistulizing Crohn's disease have not yet been published.

Case presentation

We report the cases of three patients, of European Caucasian ethnicity and Greek nationality, with active luminal and fistulizing Crohn's disease. All of the cases were treated successfully with adalimumab. Patient 1 (a 44-year-old man) and patient 2 (an 18-year-old woman) developed early post-surgical enterocutaneous fistulas, while patient 3 (a 20-year-old woman) had peri-anal fistulizing Crohn's disease. Adalimumab treatment (160 mg subcutaneously at week zero, 80 mg at week two, and 40 mg every other week) was used for three different indications: (1) after the failure of other conservative medical treatments for Crohn's disease (patient 1); (2) as a monotherapy in treating a naive patient (patient 2); (3) after an intolerance to infliximab (patient 3). A remission of the active luminal and fistulizing disease was achieved soon after the initiation of adalimumab and sustained thereafter with maintenance doses. No further surgical intervention was required and no adverse effects were observed in any of the cases.

Conclusions

Fistulizing Crohn's disease remains a challenge in clinical practice. Adalimumab seems to be an effective, well-tolerated and safe treatment option for the induction and maintenance of remission in patients with moderate to severe peri-anal fistulizing Crohn's disease. Furthermore, adalimumab seems to be a promising treatment option for patients with moderate to severe fistulizing Crohn's disease with enterocutaneous fistulas. However, this clinical observation needs to be investigated in further clinical trials.     

Association of IRGM Gene Mutations with Inflammatory Bowel Disease in the Indian Population

Background

Mutations in the IRGM gene have been associated with Crohn''s disease in several populations but have not been explored in Indian patients with this disease. This study examined the association of IRGM mutations with ulcerative colitis and Crohn''s disease in Indian patients with inflammatory bowel disease.

Methods

The IRGM gene was amplified in four segments and Sanger-sequenced in 101 participants (42 Crohn''s disease, 39 ulcerative colitis, and 20 healthy controls). Ten single nucleotide polymorphisms (SNP) were genotyped in 1200 participants (352 Crohn''s disease, 400 ulcerative colitis, and 448 healthy controls) using Sequenom MassARRAY iPLEX. Disease associations were evaluated for each of the ten SNPs.

Results

Thirty one mutations were identified in the IRGM gene, of which two had not hitherto been reported (150226250- ss947429272 & 150227858- ss947429273). Ten SNPs (6 from the above and 4 from the literature) were evaluated. Significant associations with Crohn''s disease were noted with the T allele of rs1000113 (OR 1.46, 95% CI 1.12–1.90), T allele of rs9637876 (OR 1.25, 95% CI 1.005–1.561) and C allele of rs 13361189 (OR 1.33, 95% CI 1.07–1.669). Two SNPs – rs11747270 and rs180802994 – did not exhibit Hardy-Weinberg equilibrium but were associated with both Crohn''s disease and ulcerative colitis in this population. The remaining SNPs did not show significant associations with either Crohn''s disease or ulcerative colitis.

Conclusions

Association of IRGM gene SNPs with Crohn''s disease is reported for the first time in Indian patients. We also report, for the first time, an association of rs 9637876 in the IRGM gene with Crohn''s disease.     

Immunoresponsiveness in Ulcerative Colitis and Crohn's Disease—Effect of Colectomy and Suppression of Disease Activity

We evaluated the effect of medically induced symptomatic disease improvement on in vitro tests of cell-mediated immune responses in 33 patients with Crohn''s disease. When results obtained in 17 patients with ulcerative colitis were compared with those of 10 patients with ulcerative colitis who had undergone a colectomy, no significant correlation was detected between individual clinical and laboratory variables or the Crohn''s disease activity index and in vitro tests of cell-mediated immunity. A different pattern emerged from the longitudinal tests of cell-mediated immunity: when these test results were initially abnormal in patients with Crohn''s disease, clinical improvement as assessed by the Crohn''s disease activity index was associated with normalizing cell-mediated immunity. In contrast, when the test results were initially normal, clinical improvement was not associated with any change in the immune response. Following colectomy in patients with ulcerative colitis, some abnormalities of suppressed immune responses remained, although patients were cured of their disease. Factors other than clinical disease activity may be responsible for the suppressed immunoresponsiveness in some patients with inflammatory bowel disease, and variable changes in cell-mediated immunity occur after both surgical and medical treatment.     

Finger clubbing in inflammatory bowel disease: its prevalence and pathogenesis.

Finger clubbing, measured objectively by using the hyponychial angle, was present in 75 out of 200 (38%) patients with Crohn''s disease, 15 out of 103 (15%) with ulcerative colitis, and two out of 24 (8%) with proctitis. In Crohn''s disease and ulcerative colitis the hyponychial angle was significantly correlated with both disease activity and the extent of fibrosis in the resected specimens from 47 surgically treated patients. The prevalence of finger clubbing in patients with macroscopic disease within the area of the gut innervated by the vagus nerve was significantly higher than that in patients in whom the disease was confined to the distal colon and rectum. Finger clubbing in patients with Crohn''s disease tended to regress after resection of macroscopic disease. It is concluded that finger clubbing is significantly commoner in Crohn''s disease than ulcerative colitis. The focal stimuli for finger clubbing include mucosal inflammatory change and fibrosis mediated by the vagus and possibly other autonomic pathways acting as the afferent arc of a finger-clubbing reflex.     

Farnesoid X receptor (FXR) activation and FXR genetic variation in inflammatory bowel disease

Background

We previously showed that activation of the bile salt nuclear receptor Farnesoid X Receptor (FXR) protects against intestinal inflammation in mice. Reciprocally, these inflammatory mediators may decrease FXR activation. We investigated whether FXR activation is repressed in the ileum and colon of inflammatory bowel disease (IBD) patients in remission. Additionally, we evaluated whether genetic variation in FXR is associated with IBD.

Methods

mRNA expression of FXR and FXR target gene SHP was determined in ileal and colonic biopsies of patients with Crohn''s colitis (n = 15) and ulcerative colitis (UC; n = 12), all in clinical remission, and healthy controls (n = 17). Seven common tagging SNPs and two functional SNPs in FXR were genotyped in 2355 Dutch IBD patients (1162 Crohn''s disease (CD) and 1193 UC) and in 853 healthy controls.

Results

mRNA expression of SHP in the ileum is reduced in patients with Crohn''s colitis but not in patients with UC compared to controls. mRNA expression of villus marker Villin was correlated with FXR and SHP in healthy controls, a correlation that was weaker in UC patients and absent in CD patients. None of the SNPs was associated with IBD, UC or CD, nor with clinical subgroups of CD.

Conclusions

FXR activation in the ileum is decreased in patients with Crohn''s colitis. This may be secondary to altered enterohepatic circulation of bile salts or transrepression by inflammatory signals but does not seem to be caused by the studied SNPs in FXR. Increasing FXR activity by synthetic FXR agonists may have benefit in CD patients.     

Rapid and quantitative analysis of unconjugated C(27) bile acids in plasma and blood samples by tandem mass spectrometry

A subgroup of peroxisomal disorders, peroxisome biogenesis defects (PBD), can be differentiated by elevated levels of C(27) bile acids in plasma and bile. Patients with peroxisomal disorders, who lack the ability to chain-shorten the C(27) bile acid intermediates into C(24) bile acids, show elevated levels of C(27) bile acids, notably 3 alpha,7 alpha-dihydroxy-5 beta-cholest-26-oic acid and 3 alpha,7 alpha,12 alpha-trihydroxy-5 beta-cholestan-26-oic acid. C(27) bile acids are normally estimated against other bile acid standards, by time-consuming gas chromatography-mass spectrometry and liquid chromatography-tandem mass spectrometry methods, in plasma (minimum of 50 microl). In this article we describe the quantitation of unconjugated di- and trihydroxy C(27) bile acids in 5-microl plasma samples and 3-mm blood spots, using deuterium-labeled internal standards. The synthesis of (2)H(3)-labeled di- and trihydroxycoprostanic acids is described. The sample preparation and analysis by electrospray tandem mass spectrometry (ES-MS/MS) takes less than 1 h and features dimethylaminoethyl ester derivatives. The levels of the di- and trihydroxy bile acids are significantly higher in PBD patients than in age-matched control subjects for both plasma and blood spots collected at birth (some stored for up to 18 years). Excellent correlation is observed between the C(26:0)/C(22:0) very long chain fatty acid (VLCFA) ratio and the levels of trihydroxy C(27) bile acids in plasma from PBD patients.The ES-MS/MS method can be used to rapidly screen for PBD patients in plasma samples with elevated C(26:0)/C(22:0) VLCFA ratios and in archived collections of neonatal blood spots. - Johnson, D. W., H. J. ten Brink, R. C. Schuit, and C. Jakobs. Rapid and quantitative analysis of unconjugated C(27) bile acids in plasma and blood samples by tandem mass spectrometry. J. Lipid Res. 2001. 42: 9;-16.     

Plasma analysis of di- and trihydroxycholestanoic acid diastereoisomers in peroxisomal alpha-methylacyl-CoA racemase deficiency

We identified a new peroxisomal disorder caused by a deficiency of the enzyme alpha-methylacyl-coenzyme A (CoA) racemase. Patients with this disorder show elevated plasma levels of pristanic acid and the bile acid intermediates di- and trihydroxycholestanoic acid (DHCA and THCA), which are all substrates for the peroxisomal beta-oxidation system. alpha-Methylacyl-CoA racemase plays an important role in the beta-oxidation of branched-chain fatty acids and fatty acid derivatives because it catalyzes the conversion of several (2R)-methyl-branched-chain fatty acyl-CoAs to their (2S)-isomers. Only stereoisomers with the 2-methyl group in the (S)-configuration can be degraded via beta-oxidation. In this study we used liquid chromatography/tandem mass spectrometry (LC-MS/MS) to analyze the bile acid intermediates that accumulate in plasma from patients with a deficiency of alpha-methylacyl-CoA racemase and, for comparison, in plasma from patients with Zellweger syndrome and patients with cholestatic liver disease.We found that racemase-deficient patients accumulate exclusively the (R)-isomer of free and taurine-conjugated DHCA and THCA, whereas in plasma of patients with Zellweger syndrome and patients with cholestatic liver disease both isomers were present. On the basis of these results we describe an easy and reliable method for the diagnosis of alpha-methylacyl-CoA racemase-deficient patients by plasma analysis. Our results also show that alpha-methylacyl-CoA racemase plays a unique role in bile acid formation. - Ferdinandusse, S., H. Overmars, S. Denis, H. R. Waterham, R. J. A. Wanders, and P. Vreken. Plasma analysis of di- and trihydroxycholestanoic acid diastereoisomers in peroxisomal alpha-methylacyl-CoA racemase deficiency. J. Lipid Res. 2001. 42: 137;-141.     

Integrated Metagenomics/Metaproteomics Reveals Human Host-Microbiota Signatures of Crohn's Disease

Crohn''s disease (CD) is an inflammatory bowel disease of complex etiology, although dysbiosis of the gut microbiota has been implicated in chronic immune-mediated inflammation associated with CD. Here we combined shotgun metagenomic and metaproteomic approaches to identify potential functional signatures of CD in stool samples from six twin pairs that were either healthy, or that had CD in the ileum (ICD) or colon (CCD). Integration of these omics approaches revealed several genes, proteins, and pathways that primarily differentiated ICD from healthy subjects, including depletion of many proteins in ICD. In addition, the ICD phenotype was associated with alterations in bacterial carbohydrate metabolism, bacterial-host interactions, as well as human host-secreted enzymes. This eco-systems biology approach underscores the link between the gut microbiota and functional alterations in the pathophysiology of Crohn''s disease and aids in identification of novel diagnostic targets and disease specific biomarkers.     

Smoking and Crohn's disease.

In a case-control study 82 patients with Crohn''s disease and matched controls drawn from general practice lists were questioned about their smoking habits. Patients with Crohn''s disease were significantly more likely to be smokers than the controls, and the association was stronger for smoking habit before the onset of the disease than for current smoking habit, the relative risks for smokers compared with non-smokers being 4.8 and 3.5 respectively. Taken in conjunction with earlier data showing an association between non-smoking and ulcerative colitis, these results suggest that smoking habit may be an important determinant of the type of inflammatory bowel disease that develops in predisposed subjects.