Predicting complicated Crohn's disease and surgery: phenotypes, genetics, serology and psychological characteristics of a population-based cohort

Review article: Measuring disease severity in inflammatory bowel disease - Beyond treat to target

BACKGROUND

Inflammatory bowel disease (IBD) follows a heterogenous disease course and predicting a patient's prognosis is challenging. There is a wide burden of illness in IBD and existing tools measure disease activity at a snapshot in time. Comprehensive assessment of IBD severity should incorporate disease activity, prognosis, and the impacts of disease on a patient. This review investigates the concept of disease severity in adults with IBD to highlight key components contributing to this.

METHODS

To perform this narrative review, a Medline search was conducted for full-text articles available at 1st March 2024 using search terms which encompassed disease activity assessment, disease severity, prognosis, natural history of Crohn's disease (CD) and ulcerative colitis (UC), and the burden of IBD.

RESULTS

Current methods of disease assessment in IBD have evolved from a focus on the burden of symptoms to one that includes inflammatory targets, genetic, serological, and proteomic profiles, and assessments of quality-of-life (QoL), disability, and psychosocial health. Longitudinal studies of IBD suggest that the burden of illness is driven by disease phenotype, clinical markers of complicated disease course (previous intestinal resection, corticosteroid use, perianal disease in CD, recent hospitalisations in UC), gut inflammation, and the impact of IBD on the patient.

CONCLUSIONS

Disease severity in IBD can be difficult to conceptualise due to the multitude of factors that contribute to IBD outcomes. Measurement of IBD severity may better encapsulate the full burden of illness rather than gut inflammation alone at a single timepoint and may be associated with longitudinal outcomes.

Serum amyloid A for predicting prognosis in patients with newly diagnosed Crohn's disease

OBJECTIVE

Serum amyloid A (SAA) was found to be positively correlated with the activity of Crohn's disease (CD); however, its prognostic value remains uncertain. Here, we examined its predictive ability in newly diagnosed CD and explored genetic association.

METHODS

This retrospective cohort study included patients newly diagnosed as CD at the First Affiliated Hospital of Sun Yat-sen University between June 2010 and March 2022. We employed receiver operating characteristic curve, Cox proportional hazard regression models and restricted cubic splines to investigate the prognostic performance of SAA for surgery and disease progression. To assess possible causality, a two-sample Mendelian randomisation (MR) of published genome-wide association study data was conducted.

RESULTS

During 2187.6 person-years (median age, 28 years, 72.4% male), 87 surgery and 153 disease progression events were documented. A 100-unit increment in SAA level generated 14% higher risk for surgery (adjusted HR (95% CI): 1.14 (1.05-1.23), p=0.001) and 12% for disease progression (1.12 (1.05-1.19), p<0.001). Baseline SAA level ≥89.2 mg/L led to significantly elevated risks for surgery (2.08 (1.31-3.28), p=0.002) and disease progression (1.72 (1.22-2.41), p=0.002). Such associations were assessed as linear. Adding SAA into a scheduled model significantly improved its predictive performances for surgery and disease progression (p for net reclassification indexes and integrated discrimination indexes <0.001). Unfortunately, no genetic causality between SAA and CD was observed in MR analysis. Sensitivity analyses showed robust results.

CONCLUSION

Although causality was not found, baseline SAA level was an independent predictor of surgery and disease progression in newly diagnosed CD, and had additive benefit to existing prediction models.

Mucosal Immunity to Gut Fungi in Health and Inflammatory Bowel Disease

The gut microbiome is a diverse microbial community composed of bacteria, viruses, and fungi that plays a major role in human health and disease. Dysregulation of these gut organisms in a genetically susceptible host is fundamental to the pathogenesis of inflammatory bowel disease (IBD). While bacterial dysbiosis has been a predominant focus of research for many years, there is growing recognition that fungal interactions with the host immune system are an important driver of gut inflammation. Candida albicans is likely the most studied fungus in the context of IBD, being a near universal gut commensal in humans and also a major barrier-invasive pathogen. There is emerging evidence that intra-strain variation in C. albicans virulence factors exerts a critical influence on IBD pathophysiology. In this review, we describe the immunological impacts of variations in C. lbicans colonisation, morphology, genetics, and proteomics in IBD, as well as the clinical and therapeutic implications.

Fecal fungal microbiota alterations associated with clinical phenotypes in Crohn's disease in southwest China

Although previous studies reported that gut fungal microbiota was associated with Crohn's disease (CD), only a few studies have focused on the correlation between gut fungi and clinical phenotypes of CD. Here, we aimed to analyze the association between intestinal fungi and the occurrence of CD, disease activity, biological behaviors, and perianal lesions. Stool samples from subjects meeting the inclusion and exclusion criteria were collected for running internal transcribed spacer 2 (ITS2) high-throughput sequencing. Then, correlation analysis was conducted between intestinal fungi and different clinical groups. There were 45 patients with CD and 17 healthy controls (HCs) enrolled. Results showed that two phyla, Rozellomycota and Mortierellomycota, were not present in patients with CD compared to HCs. At the same time, there was a higher abundance of fungal genera and species belonging to the phylum Ascomycota in patients with CD. SparCC network analysis showed fewer interactions among the fungal communities in patients with CD compared to HCs. Exophiala dermatitidis was positively associated with the clinical active stage and platelet count. The genus Candida was with significantly higher abundance in the non-B1 CD group based on the Montreal classification. Clonostachys, Humicola, and Lophiostoma were significantly enriched in patients with CD with perianal lesions. Our results demonstrated that the composition of the intestinal fungal microbiota in patients with CD and HCs was markedly different, some of which might play a pathogenic role in the occurrence of CD and perianal lesions. Exophiala dermatitidis and genus Candida might be associated with active disease stage and type non-B1 CD (CD with intestinal stenosis or penetrating lesions, or both), respectively.

Clinical and Genetic Factors Impact Time to Surgical Recurrence After Ileocolectomy for Crohn's Disease

OBJECTIVE

The aim of this study was to evaluate factors associated with time to surgical recurrence after Crohn's ileocolectomy.

SUMMARY BACKGROUND DATA

The most common surgery performed for Crohn's disease is ileocolectomy. Identifying patients at high risk for surgical recurrence may assist with medical and surgical decision-making.

METHODS

Data were obtained from 409 patients with Crohn's disease (CD) who had undergone ≥1 ileocolectomies at Penn State Hershey Medical Center. Six single-nucleotide polymorphisms (SNPs) associated with CD were evaluated in these patients: rs2076756, rs2066844, and rs2066845 in NOD2, rs4958847 and rs13361189 in IRGM, and rs2241880 in ATG16L1. Genotype and clinical factors were analyzed to determine associations with time to recurrent ileocolectomy. A subgroup analysis was performed on 241 patients naïve to biologics before initial ileocolectomy to assess the effect of biologic therapy on time to recurrent surgery.

RESULTS

There were 286 patients who underwent a single ileocolectomy, whereas 123 required multiple ileocolectomies. Ileocolonic involvement [hazard ratio (HR) 1.90, 95% confidence interval (CI) 1.21-3.00, P = 0.006] and rs2066844 in NOD2 (HR 1.8, 95% CI 1.17-2.77, P = 0.007) were associated with decreased time to surgical recurrence by multivariate analysis. In patients naïve to preoperative biologics, the initiation of postoperative biologics was associated with a 40% decreased incidence of surgical recurrence (HR 0.60, CI 0.39-0.93, P = 0.02) over time.

CONCLUSIONS

Ileocolonic distribution of disease and the rs2066844 SNP in NOD2 are associated with shorter time to recurrent ileocolectomy. The initiation of postoperative biologics in naïve patients was associated with a reduced incidence of recurrence over time.

Prognostic biomarkers to identify patients likely to develop severe Crohn's disease: a systematic review

BACKGROUND

Identification of biomarkers that predict severe Crohn's disease is an urgent unmet research need, but existing research is piecemeal and haphazard.

OBJECTIVE

To identify biomarkers that are potentially able to predict the development of subsequent severe Crohn's disease.

DESIGN

This was a prognostic systematic review with meta-analysis reserved for those potential predictors with sufficient existing research (defined as five or more primary studies).

DATA SOURCES

PubMed and EMBASE searched from inception to 1 January 2016, updated to 1 January 2018.

REVIEW METHODS

Eligible studies were studies that compared biomarkers in patients who did or did not subsequently develop severe Crohn's disease. We excluded biomarkers that had insufficient research evidence. A clinician and two statisticians independently extracted data relating to predictors, severe disease definitions, event numbers and outcomes, including odds/hazard ratios. We assessed risk of bias. We searched for associations with subsequent severe disease rather than precise estimates of strength. A random-effects meta-analysis was performed separately for odds ratios.

RESULTS

In total, 29,950 abstracts yielded just 71 individual studies, reporting 56 non-overlapping cohorts. Five clinical biomarkers (Montreal behaviour, age, disease duration, disease location and smoking), two serological biomarkers (anti-Saccharomyces cerevisiae antibodies and anti-flagellin antibodies) and one genetic biomarker (nucleotide-binding oligomerisation domain-containing protein 2) displayed statistically significant prognostic potential. Overall, the strongest association with subsequent severe disease was identified for Montreal B2 and B3 categories (odds ratio 4.09 and 6.25, respectively).

LIMITATIONS

Definitions of severe disease varied widely, and some studies confounded diagnosis and prognosis. Risk of bias was rated as 'high' in 92% of studies overall. Some biomarkers that are used regularly in daily practice, for example C-reactive protein, were studied too infrequently for meta-analysis.

CONCLUSIONS

Research for individual biomarkers to predict severe Crohn's disease is scant, heterogeneous and at a high risk of bias. Despite a large amount of potential research, we encountered relatively few biomarkers with data sufficient for meta-analysis, identifying only eight biomarkers with potential predictive capability.

FUTURE WORK

We will use existing data sets to develop and then validate a predictive model based on the potential predictors identified by this systematic review. Contingent on the outcome of that research, a prospective external validation may prove clinically desirable.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42016029363.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 25, No. 45. See the NIHR Journals Library website for further project information.

Classifying Crohn's disease into colon-involving versus non-colon-involving groups is a better predictor of clinical outcomes than the Montreal classification

BACKGROUND

A suitable disease classification is essential for individualized therapy in patients with Crohn's disease (CD). Although a potential mechanistic classification of colon-involving and non-colon-involving disease was suggested by recent genetic and microbiota studies, the clinical implication has seldom been investigated. We aimed to explore the association of this colonic-based classification with clinical outcomes in patients with CD compared with the Montreal classification.

METHODS

This was a retrospective study of CD patients from a tertiary referral center. Patients were categorized into colon-involving and non-colon-involving disease, and according to the Montreal classification. Clinico-demographic data, medications, and surgeries were compared between the two classifications. The primary outcome was the need for major abdominal surgery.

RESULTS

Of 934 patients, those with colonic involvement had an earlier median (interquartile range) age of onset [23.0 (17.0-30.0) versus 26.0 (19.0-35.0) years, p = 0.001], higher frequency of perianal lesions (31.2% versus 14.5%, p < 0.001) and extraintestinal manifestations (21.8% versus 14.5%, p = 0.010), but lower frequency of stricture (B2) (16.3% versus 24.0%, p = 0.005), than those with non-colon-involving disease. Colon-involving disease was a protective factor against major abdominal surgery [hazard ratio, 0.689; 95% confidence interval (CI), 0.481-0.985; p = 0.041]. However, patients with colon-involving CD were more prone to steroids [odds ratio (OR), 1.793; 95% CI, 1.206-2.666; p = 0.004] and azathioprine/6-mercaptopurine (AZA/6-MP) treatment (OR, 1.732; 95% CI, 1.103-2.719; p = 0.017) than were patients with non-colon-involving disease. The Montreal classification was not predictive of surgery or steroids and AZA/6-MP treatment.

CONCLUSION

This study supports the rationale for disease classification based on the involvement of colon. This new classification of CD is a better predictor of clinical outcomes than the Montreal classification.

Bowel Damage at Diagnosis Using the Lémann Index Score in Saudi Arabian Patients With Crohn's Disease

Background

Advanced bowel damage caused by Crohn’s disease (CD) in the form of strictures and penetrating lesions has been associated with future surgical resection. However, in general, the degree of bowel damage in patients with CD is not examined at the time of diagnosis, and the natural history of CD may differ phenotypically between patients from Arabic countries as compared to patients from Europe and North America. Thus, we aimed to assess the degree of structural bowel damage in Saudi Arabian CD patients at diagnosis. We used the Lémann Index (LI) score, an instrument that measures cumulative digestive tissue damage by magnetic resonance enterography (MRE) and endoscopy, to establish any possible association between the duration of symptoms and the degree of bowel damage.

Method

This retrospective study was conducted by reviewing the data of all CD patients following up at King Abdulaziz University Hospital (KAUH) that were investigated by endoscopy and MRE at baseline. MRE-LI was calculated by scoring previous surgery, disease location and extension, and intestinal complications. A LI score of >2.0 was set as the cut-off point for bowel damage. Descriptive statistics were used to provide an overview of demographic and clinical characteristics, and hypothesis testing was applied to identify associations.

Result

Eighty-three patients with CD were included in this study. Fifty point six percent (50.6%) of the cohort comprised females and the median age was 27 years. With regards to CD location and extension, 34.9% showed ileal disease (L1), 9.6% showed colonic CD (L2), whereas 55.4% had ileocolonic involvement (L3). Moreover, 48.2% of patients presented with non-complicated behavior (B1), 25.3% had at least one stricture (B2), and 26.5% showed a penetrating phenotype (B3). Perianal CD was observed in 2.4% of subjects and 62.7% had undergone bowel resection. Mean LI was 2.4 (±2.6) with 34 patients (39.8%) exhibiting an LI score indicative of advanced bowel damage at the time of diagnosis. The duration of symptoms did not correlate with the degree of bowel damage according to the LI score.

Conclusion

A significant proportion of patients with CD presented with advanced bowel damage at the time of diagnosis, suggesting that a severe form of CD may be endemic in Saudi Arabia.

Serum biomarkers of fibrostenotic Crohn's disease: Where are we now?

Intestinal fibrosis and subsequent stricture formation are major clinical challenges in inflammatory bowel disease, resulting in an increased rate of operation and poor prognosis compared with those without. With the changing perception that intestinal fibrosis is irreversible to the point of view that it is reversible in recent years, various candidate serum biomarkers have been studied over the past decades, which may stratify patients based on their risks of developing stenosis and enable the detection of early stages of fibrosis. However, reliable and accurate biomarkers are still unavailable due to conflicting results and the lack of high-quality evidence. In this review we summarized the serum biomarkers that have been proposed for intestinal fibrosis in recent years, which includes gene polymorphisms or variants, epigenetic markers, extracellular matrix components, growth factors, and antibodies, aiming to provide clues for future research.

Identifying Patients With Inflammatory Bowel Diseases at High vs Low Risk of Complications

People with Crohn's disease and ulcerative colitis have varying presentations and clinical consequences of their disease. Patients commonly ask about their prognosis, and what this diagnosis means for them. They are asking their clinicians to predict the future. The importance of predicting the course of any disease is to guide patient expectations and to guide treatment decisions. In the past decade the strategy of inflammatory bowel disease (IBD) treatment has shifted to treat patients earlier in the course of their disease, before irreversible damage occurs. Treatment approaches for disease categorized as mild, moderate or severe has most often been based on a current assessment of symptoms or disease activity without including a longitudinal assessment of a patient's disease course including past disease complications and surgeries. While a patient's current disease activity most typically drives these treatment decisions, optimally, treatment decisions would be made accounting for past disease activity and complications and the predicted future disease course. When developing a treatment plan for an individual patient, the immediate goal is to treat the current disease activity for relief of symptoms, and the long-term goal is to prevent progression of their disease due to complications. Since not all patients will progress to a complicated disease course, it is important to be able to select the right patients for the right therapy. Therefore, developing methods of stratifying patients into low-risk versus high-risk of complications will be an important aspect of treating IBD now and in the future.

Variation of Gut Mucosal Microbiome With Anti-Saccharomyces cerevisiae Antibody Status in Pediatric Crohn Disease

OBJECTIVES

Crohn disease (CD) is a chronic relapsing condition possibly caused by a dysbiotic microbiome. Approximately 30% to 60% of patients with CD have anti-Saccharomyces cerevisiae antibody (ASCA), but any association with gut microbiota is unexplored. We hypothesized that ASCA positivity would predict a signature microbial status and clinical phenotype.

METHODS

Ileocolonic mucosal biopsies were obtained from children with CD (n = 135), and controls without inflammatory bowel disease (n = 45). Comparison was made between ASCA status, microbial diversity, and clinical characteristics.

RESULTS

ASCA was highly specific but poorly sensitive for the diagnosis of CD. In patients with CD, ASCA positivity was associated with older age (≥10 years), ileocolonic disease, and long-term risk of surgery. Microbial alpha and beta diversity were similar in patients with CD with or without ASCA, but significantly less when compared to noninflammatory bowel disease controls. Microbial richness was similar across all 3 groups. Fourteen bacterial species were associated with ASCA-positive patients with CD and 14 species with ASCA-negative patients (P < 0.05). After using a false discovery rate correction Ruminococcus torques and bacterium Yersinia enterocolitica 61 remained significantly associated with CD ASCA positivity (P = 0.0178), whereas Enterobacter cloacae and Faecalibacterium prausnitzii were significantly associated with CD ASCA negativity (P = 0.0178 and 0.0342).

CONCLUSION

ASCA-positive and ASCA-negative patients with CD have significant differences in gut microbiome composition, which could possibly be influencing the phenotype of the disease.

Impact of Genes and the Environment on the Pathogenesis and Disease Course of Inflammatory Bowel Disease

Crohn's disease and ulcerative colitis constitute two major subgroups of inflammatory bowel diseases (IBD), a group of complex polygenic diseases characterized by chronic and progressive inflammation in the gastrointestinal tract. In recent years, methodological advances in genetic analysis have greatly expanded our understanding of the genetic background of IBD. So far, more than 240 genetic risk loci have been identified for IBD. However, these risk alleles explain less than 30% of the susceptibility to disease development, suggesting that environmental factors contribute considerably. The increasing occurrence of IBD in Eastern countries following their 'westernization', as well as the increased risk of disease among those who migrate to high-incidence regions, also suggest that the environment is key in the pathogenesis of IBD. In this review, we summarize the current evidence on the role of genetic and environmental factors in the susceptibility to, and disease course of, IBD, and we suggest how these findings might be applied to clinical practice.

Reappraisal of antibodies against Saccharomyces cerevisiae (ASCA) as persistent biomarkers in quiescent Crohn's disease

A clear correlation exists between microbiota and the dysregulation of the immune response in Inflammatory Bowel Diseases (IBD), which comprise Crohn's disease (CD) and ulcerative colitis (UC). These unbalanced reactions also involve humoral responses, with antibodies against Saccharomyces cerevisiae. Thus, here we aimed to quantify IgA and IgG specific to S. cerevisiae (ASCA) in quiescent CD and UC, to correlate the production of these antibodies with patient's inflammatory response and disease clinical presentation. Twenty-nine subjects (16 CD and 13 UC) and 45 healthy controls were enrolled in this study and had plasma samples tested for ASCA and cytokines (IL-2, IL-4, IL-6, IL-10, IFN-γ, TNF-α), besides clinical evaluation. IBD patients had increase IgA and IgG ASCA, especially those with colonic (L2) and fistulizing (B3) CD. Similarly, patients who dropped out the treatment had augmented ASCA, while IgG was reduced in those receiving sulfasalazine treatment. Furthermore, the quiescent CD patients had elevated IL-6 on plasma, especially in the absence of treatment, together with increased counter regulatory response of IL-10. There was a positive correlation between IgA and IgG on CD but not UC, as well as between IgA and TNF in total IBD patients. In addition, the levels of IgG x TNF, IgA x IL-10 and IgG x IL-10 were also correlated in CD, indicating that ASCA production may be influenced by the inflammatory response. Finally, we concluded that ASCA could be pointed as relevant biomarker of CD presentation and residual inflammation, even in clinical remission patients.

Biologics Delay Progression of Crohn's Disease, but Not Early Surgery, in Children

BACKGROUND & AIMS

Up to 30% of patients with Crohn's disease (CD) require surgery within the first 5 years from diagnosis. We investigated the recent risk of bowel surgery in an inception cohort of pediatric patients with CD and whether early use of biologics (tumor necrosis factor antagonists) alters later disease course.

METHODS

We collected data from the Pediatric Inflammatory Bowel Disease Collaborative Research Group registry on 1442 children (age, ≤16 y) diagnosed with CD from January 2002 through December 2014. Data were collected at diagnosis, 30 days following diagnosis, and then quarterly and during hospitalizations for up to 12 years. Our primary aim was to determine the 10-year risk for surgery in children with CD. Our secondary aim was to determine whether early use of biologics (<3 mo of diagnosis) affected risk of disease progression.

RESULTS

The 10-year risk of first bowel surgery was 26%. The 5-year risk of bowel surgery did not change from 2002 through 2014, and remained between 13% and 14%. Most surgeries occurred within 3 years from diagnosis. The only predictor of surgery was disease behavior at diagnosis. CD with inflammatory behavior had the lowest risk of surgery compared to stricturing disease, penetrating disease, or both. We associated slowing of disease progression to stricturing or penetrating disease (but not surgery) with early use of biologics, but this effect only became evident after 5 years of disease. Our results indicate that biologics slow disease progression over time (hazard ratio, 0.85; 95% CI, 0.76-0.95).

CONCLUSIONS

In an analysis of data from a registry of pediatric patients with CD, we found that among those with significant and progressing disease at or shortly after presentation, early surgery is difficult to prevent, even with early use of biologics. Early use of biologics (<3 mo of diagnosis) can delay later disease progression to stricturing and/or penetrating disease, but this affect could become evident only years after initial management decisions are made.

Lémann Index at Diagnosis Predicts the Risk of Early Surgery in Crohn's Disease

BACKGROUND

Identifying patients with Crohn's disease with rapid disease progress or high risk of early surgery is crucial to clinical decision making.

OBJECTIVE

The aim was to evaluate the correlation between the Lémann index at diagnosis and abdominal surgery in the first year after Crohn's disease diagnosis and to find the risk factors for early surgery.

DESIGN

This was a retrospective cohort study.

SETTINGS

The study was conducted at a single tertiary hospital.

PATIENTS

Patients diagnosed with Crohn's disease between 2013 and 2015 in our center were included.

MAIN OUTCOME MEASURES

The outcome of interest was the need for an abdominal surgery within 1 year after the Lémann index evaluation at diagnosis.

RESULTS

Of 212 eligible patients, 48 patients underwent abdominal surgery during follow-up. Lémann index was much higher in the surgery group (5.3 vs 2.6; p < 0.001). On tertiles of the Lémann index, the frequency of surgery grew (2.8%, 9.9%, and 55.7%; p < 0.001) as the Lémann index increased. The receiver operating characteristic curve was constructed taking into account the Lémann index for selecting patients with a high risk of surgery. Specificity, sensitivity, and area under receiver operating characteristic curve were 84.8%, 81.3%, and 0.89 of the Lémann Index at a cutoff level of 3.7. Patients with Lémann index ≥3.7 carried a higher risk of abdominal surgery (OR = 18.6; p < 0.001). Stricturing and penetrating disease were predictors for abdominal surgery, whereas antitumor necrosis factor treatment was associated with a significant reduction of surgical requirements.

LIMITATIONS

This study was limited by its retrospective design. The ability of the Lémann index to predict the long-term risk of surgery was unknown.

CONCLUSIONS

Lémann index at diagnosis is a reliable index to predict the risk of abdominal surgery in the first year after diagnosis of Crohn's disease. Patients with a high Lémann index might need closer follow-up or aggressive medical therapy. See Video Abstract at http://links.lww.com/DCR/A518.

Risk Stratification for Surgery in Stricturing Ileal Crohn's Disease: The BACARDI Risk Model

BACKGROUND AND AIM

Transmural inflammation in Crohn's disease [CD] leads to stricturing or penetrating complications. Factors impacting on the need and timing of surgery in ileal stricturing CD [IS-CD] are understudied. Our aim was to identify risk factors in IS-CD associated with the need for surgery over time.

METHODS

All cross-sectional imaging [XSI] performed for CD between 2006 and 2015 in a tertiary referral centre was analysed. The electronic charts of patients with IS-CD were reviewed for demographic, clinical, biochemical, imaging, genetic, and endoscopic factors. An independent cohort was used for validation.

RESULTS

A total of 1803 XSI were performed in 957 patients with CD. IS-CD was diagnosed in 235 patients, and 161 of these [69%] needed surgery. Prestenotic dilation (hazard ratio [HR] 2.05, 95% confidence interval [CI] 1.22-3.45, p = 0.007], C-reactive protein at diagnosis of IS-CD > 11 mg/L [HR 1.53, 95% CI 1.05-2.24, p = 0.026], Montreal B3 phenotype [HR 1.58, 95% CI 1.06-2.36, p = 0.023], previous/current anti-tumour necrosis factor [TNF] exposure [HR 1.44, 95% CI 1.00-2.06, p = 0.048], and presence of at least one NOD2 rs2066844 risk allele [HR 1.51, 95% CI 1.02-2.23, p = 0.038] significantly impacted on the need for surgery in multivariate analysis. The risk stratification model [BACARDI] yielded a surgery-free survival after 5 years of 77%, 38%,19%, and 0% for the low, medium, high, and all risk groups, respectively. Based on an independent cohort of 27 patients, the results were validated and demonstrated adequate performance.

CONCLUSIONS

This risk model can facilitate therapeutic decisions in IS-CD and suggest the correct time for surgery in daily clinical practice.

Development of Clinical Prediction Models for Surgery and Complications in Crohn's Disease

BACKGROUND AND AIMS

Crohn's disease-related complications account for a substantial proportion of inflammatory bowel disease-associated health care expenditure. Identifying patients at risk for complications may allow for targeted use of early therapeutic interventions to offset this natural course. We aimed to develop risk prediction models for Crohn's disease-related surgery and complications.

METHODS

Using data from the Randomised Evaluation of an Algorithm for Crohn's Disease cluster-randomised clinical Trial [REACT], which involved 1898 patients from 40 community practices, separate prediction models were derived and internally validated for predicting Crohn's disease-related surgery and disease-related complications [defined as the first disease-related surgery, hospitalisation, or complication within 24 months]. Model performance was assessed in terms of discrimination and calibration, decision curves, and net benefit analyses.

RESULTS

There were 130 [6.8%] disease-related surgeries and 504 [26.6%] complications during the 24-month follow-up period. Selected baseline predictors of surgery included age, gender, disease location, Harvey-Bradshaw Index [HBI] score, stool frequency, antimetabolite or 5-aminosalicylate use, and the presence of a fistula, abscess, or abdominal mass. Selected predictors of complications included those same factors for surgery, plus corticosteroid or anti-tumour necrosis factor use, but excluded 5-aminosalicylate use. Discrimination ability, as measured by validated c-statistics, was 0.70 and 0.62 for the surgery and complication models, respectively. Score charts and nomograms were developed to facilitate future risk score calculation.

CONCLUSIONS

Separate risk prediction models for Crohn's disease-related surgery and complications were developed using clinical trial data involving community gastroenterology practices. These models could be used to guide Crohn's disease management. External validation is warranted.

The SLC2A14 gene, encoding the novel glucose/dehydroascorbate transporter GLUT14, is associated with inflammatory bowel disease

Background: Variations in intestinal antioxidant membrane transporters are implicated in the initiation and progression of inflammatory bowel disease (IBD). Facilitated glucose transporter member 14 (GLUT14), encoded by the solute carrier family 2 member 14 (SLC2A14) gene, is a putative transporter for dehydroascorbic acid and glucose. Although information on the gene is limited, shorter and longer GLUT14 isoforms have been identified. We hypothesized that GLUT14 mediates glucose and dehydroascorbic acid uptake. If this function could be validated, then genetic variations may associate with IBD.Objective: This study aimed to determine the substrate(s) for the GLUT14 protein and interrogated genetic associations of SLC2A14 with IBD.Design: The uptake of radiolabeled substrates into Xenopus laevis oocytes expressing the 2 GLUT14 isoforms was assessed. Examination of gene-targeted genetic association in the Manitoba Inflammatory Bowel Disease Cohort Study was conducted through the genotyping of single nucleotide polymorphisms (SNPs) representing linkage blocks of the SLC2A14 gene.Results: Both GLUT14 isoforms mediated the uptake of dehydroascorbic acid and glucose into X. laevis oocytes. Three alleles in the SLC2A14 gene associated independently with IBD. The odds of having ulcerative colitis (UC) or Crohn disease (CD) were elevated in carriers of the SLC2A14 SNP rs2889504-T allele (OR: 3.60; 95% CI: 1.95, 6.64 and OR: 4.68; 95% CI: 2.78, 8.50, respectively). Similarly, the SNP rs10846086-G allele was associated with an increased risk of both UC and CD (OR: 2.91; 95% CI: 1.49, 5.68 and OR: 3.00; 95% CI: 1.55, 5.78, respectively). Moreover, the SNP rs12815313-T allele associated with increased susceptibility to CD and UC (OR: 2.12; 95% CI: 1.33, 3.36 and OR: 1.61; 95% CI: 1.01, 2.57, respectively).Conclusion: These findings strengthen the hypothesis that genetically determined local dysregulation of dietary vitamin C or antioxidants transport contributes to IBD development. These transporter proteins are targetable by dietary interventions, opening the avenue to a precision intervention for patients of specific genotypes with IBD. This trial was registered at clinicaltrials.gov as NCT03262649.

The value of serum antibodies in differentiating inflammatory bowel disease, predicting disease activity and disease course in the newly diagnosed patient

BACKGROUND

Data on serum antibodies in untreated adult inflammatory bowel disease (IBD) patients at diagnosis are scarcely available, and results on the stability of antibody presence over time are inconsistent. Our aim was to investigate antibodies in newly diagnosed, untreated IBD patients in relation to disease phenotype and course. Furthermore, we analyzed antibody presence over time.

METHODS

Baseline anti-Saccharomyces cerevisiae antibodies (ASCA), anti-chitobioside carbohydrate antibodies (ACCA), anti-laminaribioside carbohydrate antibodies (ALCA) and anti-mannobioside carbohydrate antibodies (AMCA) were measured with enzyme-linked immunosorbent assays and perinuclear anti-neutrophilic cytoplasmic antibodies (pANCA) was measured by indirect immunofluorescence in serum of 120 untreated IBD patients at diagnosis and 19 healthy controls. Antibodies were related to disease outcomes. Serial measurements were available in 71 patients.

RESULTS

The combination of pANCA and ASCA enabled good discrimination between UC and CD (p = .004). Antibody presence was relatively stable over time, even though there were significant changes in concentrations. There was a trend towards larger fluctuations in concentration with immunosuppressive medication. Baseline pANCA in UC patients correlated with calprotectin values (rho = .545, p = .019) and change in pANCA status over time was associated with disease activity at that moment. No associations were found with antibodies at diagnosis and disease outcomes.

CONCLUSION

Antibody profiles at diagnosis support the distinction between CD and UC. Anti-glycan antibodies are reasonably stable over time, but may fluctuate under the influence of immunosuppressive treatment which may explain the inconsistency in findings hitherto. The appearance or disappearance of pANCA antibodies during follow-up correlated with disease activity in UC and may be used in disease monitoring.

IBD血清学标志物的临床应用前景

炎症性肠病(inflammatory bowel disease, IBD)是一种病因不明的慢性非特异性肠道炎症性疾病, 包括溃疡性结肠炎(ulcerative colitis, UC)和克罗恩病(Crohn's disease, CD). 目前IBD的诊断及临床过程主要依据其临床表现、常规检验、影像学特征、内镜所见及组织病理综合判断, 但远未满足临床实践. 因此, 寻找一种简单、准确的诊断方法成为目前亟待解决的问题. 迄今, IBD相关血清学标志物的应用对IBD的诊断与鉴别诊断、疾病严重程度界定、疗效判断和预后评估均凸显出其临床优势. 本文就近年来IBD血清学标志物的研究及其临床应用前景作一述评.

Misbalance in type III collagen formation/degradation as a novel serological biomarker for penetrating (Montreal B3) Crohn's disease

BACKGROUND

Misbalances in extracellular matrix turnover are key factors in the development of stricturing (Montreal B2) and penetrating (Montreal B3) Crohn's disease.

AIM

To determine whether serological markers for collagen formation and degradation could serve as biomarkers for complications of Crohn's disease.

METHODS

Serum biomarkers for type I, III, V and VI collagen formation (P1NP, Pro-C3, Pro-C5, Pro-C6) and matrix metalloproteinase mediated degradation (C1M, C3M, C5M and C6M) were measured in a retrospective, single centre cohort of 112 patients with Crohn's disease in the terminal ileum (nonstricturing/nonpenetrating: n=40, stricturing: n=55, penetrating: n=17) and 24 healthy controls. Active inflammation was defined as CRP >5 mg/L.

RESULTS

C3M and Pro-C5 levels were higher in penetrating vs nonpenetrating/nonstricturing and stricturing disease (33.6±5 vs 25.8±2.2 [P=.004] and 27.2±2.3 [P=.018] nmol/L C3M, 1262.7±259.4 vs 902.9±109.9 [P=.005] and 953.0±106.4 [P=.015] nmol/L Pro-C5). C1M (71.2±26.1 vs 46.2±6.2 nmol/L [P<.001]), C3M (31.6±3.9 vs 26.1±1.6 nmol/L [P=.002] and Pro-C5 levels (1171.7±171.5 vs 909.6±80.4 nmol/L [P=.002]) were higher in patients with active inflammation vs without active inflammation. Pro-C3/C3M-ratios were best to differentiate between penetrating vs nonstricturing/nonpenetrating and stricturing disease with area under the curves of 0.815±0.109 (P<.001) and 0.746±0.114 (P=.002) respectively.

CONCLUSIONS

Serological biomarkers show that penetrating Crohn's disease is characterised by increased matrix metalloproteinase-9 degraded type III collagen and formation of type V collagen. Active inflammation in Crohn's disease is characterised by increased formation of type V collagen and increased matrix metalloproteinase mediated breakdown of type I, III collagen. Pro-C3/C3M ratios are superior in differentiating between penetrating Crohn's disease vs inflammatory and stricturing Crohn's disease.

Serologic antibodies in relation to outcome in postoperative Crohn's disease

BACKGROUND AND AIM

Disease recurs frequently after Crohn's disease resection. The role of serological antimicrobial antibodies in predicting recurrence or as a marker of recurrence has not been well defined.

METHODS

A total of 169 patients (523 samples) were prospectively studied, with testing peri-operatively, and 6, 12 and 18 months postoperatively. Colonoscopy was performed at 18 months postoperatively. Serologic antibody presence (perinuclear anti-neutrophil cytoplasmic antibody [pANCA], anti-Saccharomyces cerevisiae antibodies [ASCA] IgA/IgG, anti-OmpC, anti-CBir1, anti-A4-Fla2, anti-Fla-X) and titer were tested. Quartile sum score (range 6-24), logistic regression analysis, and correlation with phenotype, smoking status, and endoscopic outcome were assessed.

RESULTS

Patients with ≥ 2 previous resections were more likely to be anti-OmpC positive (94% vs 55%, ≥ 2 vs < 2, P = 0.001). Recurrence at 18 months was associated with anti-Fla-X positivity at baseline (49% vs 29%; positive vs negative, P = 0.033) and 12 months (52% vs 31%, P = 0.04). Patients positive (n = 28) for all four antibacterial antibodies (anti-CBir1, anti-OmpC, anti-A4-Fla2, and anti-Fla-X) at baseline were more likely to experience recurrence at 18 months than patients negative (n = 32) for all four antibodies (82% vs 18%, P = 0.034; odds ratio 6.4, 95% confidence interval 1.16-34.9). The baseline quartile sum score for all six antimicrobial antibodies was higher in patients with severe recurrence (Rutgeert's i3-i4) at 18 months, adjusted for clinical risk factors (odds ratio 1.16, 95% confidence interval 1.01-1.34, P = 0.039). Smoking affected antibody status.

CONCLUSIONS

Anti-Fla-X and presence of all anti-bacterial antibodies identifies patients at higher risk of early postoperative Crohn's disease recurrence. Serologic screening pre-operatively may help identify patients at increased risk of recurrence.

Serological Epithelial Component Proteins Identify Intestinal Complications in Crohn's Disease

Crohn's Disease (CD) is a relapsing inflammation of the gastrointestinal tract that affects a young working age population and is increasing in developing countries. Half of all sufferers will experience stricturing or fistulizing intestinal complications that require extensive surgical interventions and neither genes nor clinical risk factors can predict this debilitating natural history. We applied discovery and verification phase studies as part of an NCI-FDA modeled biomarker pipeline to identify differences in the low-mass (<25kDa) blood-serum proteome between CD behavioral phenotypes. A significant enrichment of epithelial component proteins was identified in CD patients with intestinal complications using quantitative proteomic profiling with label-free Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS). DAVID 6.7 (NIH) was used for functional annotation analysis of detected proteins and immunoblotting and multiple reaction monitoring (MRM) to verify a priori findings in a secondary independent cohort of complicated CD (CCD), uncomplicated inflammatory CD (ICD), Th1/17 pathway inflammation controls (rheumatoid arthritis), inflammatory bowel disease controls (ulcerative colitis), and healthy controls. Seventy-six high-confidence serum proteins were modulated in CCD versus ICD by LC-MS/MS (p < 0.05, FDR q<0.01), annotating to pathways of epithelial barrier homeostasis (p < 0.01). In verification phase, a putative serology panel developed from discovery proteomics data consisting of desmoglein-1, desmoplakin, and fatty acid-binding protein 5 (FABP5) distinguished CCD from all other groups (p = 0.041) and discriminated complication in CD (70% sensitivity and 72.5% specificity at score ≥1.907, AUC = 0.777, p = 0.007). An MRM assay secondarily confirmed increased FABP5 levels in CCD (p < 0.001). In a longitudinal subanalysis-cohort, FABP5 levels were stable over a two-month period with no behavioral changes (p = 0.099). These studies along the biomarker development pipeline provide substantial proof-of-principle that a blood test can be developed specific to transmural intestinal injury. Data are available via the PRIDE proteomics data repository under identifier PXD001821 and PeptideAtlas with identifier PASS00661.

Crohn's disease

Crohn's disease is a chronic inflammatory disease of the gastrointestinal tract, with increasing incidence worldwide. Crohn's disease might result from a complex interplay between genetic susceptibility, environmental factors, and altered gut microbiota, leading to dysregulated innate and adaptive immune responses. The typical clinical scenario is a young patient presenting with abdominal pain, chronic diarrhoea, weight loss, and fatigue. Assessment of disease extent and of prognostic factors for complications is paramount to guide therapeutic decisions. Current strategies aim for deep and long-lasting remission, with the goal of preventing complications, such as surgery, and blocking disease progression. Central to these strategies is the introduction of early immunosuppression or combination therapy with biologicals in high-risk patients, combined with a tight and frequent control of inflammation, and adjustment of therapy on the basis of that assessment (treat to target strategy). The therapeutic armamentarium for Crohn's disease is expanding, and therefore the need to develop biomarkers that can predict response to therapies will become increasingly important for personalised medicine decisions in the near future. In this Seminar, we provide a physician-oriented overview of Crohn's disease in adults, ranging from epidemiology and cause to clinical diagnosis, natural history, patient stratification and clinical management, and ending with an overview of emerging therapies and future directions for research.

Serological markers in diagnosis of pediatric inflammatory bowel disease and as predictors for early tumor necrosis factor blocker therapy

OBJECTIVE

To describe the prevalence of serological markers in newly diagnosed treatment-naïve pediatric inflammatory bowel disease (IBD), their utility in differentiating Crohn's disease (CD), ulcerative colitis (UC) and symptomatic non-IBD patients and whether serological markers are associated with early TNF blocker treatment.

MATERIAL AND METHODS

Ninety-six children and adolescents <18 years, 58 with IBD and 38 symptomatic non-IBD controls were included. At diagnosis and after 1-2 years, serological antibodies (anti-Saccharomyces cerevisiae antibodies (ASCA), perinuclear anti-neutrophil cytoplasmic antibody (pANCA), flagellin expressed by Clostridial phylum (anti-CBir1), outer membrane porin of Escherichia coli (anti-OmpC), Pseudomonas fluorescens-associated sequence (anti-I2), CRP, ESR and fecal calprotectin were analyzed. The choice of treatment was made at the discretion of the treating pediatrician.

RESULTS

Of the IBD patients, 20 (36%) and 26 (47%) were positive for ASCA and pANCA compared to 3(8%), p < .01 and 10 (27%), p = .04 of the controls. Thirteen (72%) of UC patients were pANCA positive, versus 13 (35%) of CD patients (p < .01). None of the UC patients was ASCA positive versus 20 (54%) of CD patients (p < .0001). Compared to conventionally treated patients, the 18 (49%) TNF blocker treated CD patients had higher presence of ASCA (p < .01), lower presence of pANCA (p = .02) and higher levels of fecal calprotectin, CRP and ESR at diagnosis. In multivariate analyses ASCA and pANCA status, but not CRP, ESR or calprotectin, were independently associated with early TNF blocker treatment.

CONCLUSIONS

ASCA and pANCA status were associated with having IBD and with early TNF blocker treatment in CD.

Genetic risk variants as therapeutic targets for Crohn's disease

INTRODUCTION

The pathogenesis of Inflammatory bowel diseases (IBD) is multifactorial, with interactions between genetic and environmental factors. Despite the existence of genetic factors being largely demonstrated by epidemiological data and several genetic studies, only a few findings have been useful in term of disease prediction, disease progression and targeting therapy. Areas covered: This review summarizes the results of genome-wide association studies in Crohn's disease, the role of epigenetics and the recent discovery by genetic studies of new pathogenetic pathways. Furthermore, it focuses on the importance of applying genetic data to clinical practice, and more specifically how to better target therapy and predict potential drug-related toxicity. Expert opinion: Some genetic markers identified in Crohn`s disease have allowed investigators to hypothesize about, and in some cases, prove the usefulness of new specific therapeutic agents. However, the heterogeneity and complexity of this disease has so far limited the daily clinical use of genetic information. Finally, the study of the implications of genetics on therapy, either to predict efficacy or avoid toxicity, is considered still to be in its infancy.

Radiologic Predictors of Surgery in Newly Diagnosed Pediatric Crohn Disease Patients

OBJECTIVES

The aim of the present study was to assess whether small bowel imaging conducted at the time of diagnosis could be used as a predictor of small bowel surgical intervention in a population of pediatric patients with Crohn disease (CD).

METHODS

A retrospective analysis of small bowel imaging within 30 days of diagnosis of pediatric CD was conducted. Patients were divided into 2 groups based on small bowel imaging: those with no or minor abnormalities (71%) and those with more extensive or obstructive abnormalities (29%). Medical records were reviewed for small bowel surgical intervention and clinic follow-up visits.

RESULTS

A total of 232 patients were included in the study group (average age at diagnosis 11.7 years). Twenty-seven patients (12%) underwent small bowel surgical intervention. The relative risk for small bowel surgical intervention was 2.91 in the group with more extensive imaging abnormalities. The majority of increased surgical risk occurred in the first year after diagnosis, when the normal-minor group had a 2% surgical risk and the more abnormal group had a 17% surgical risk. Both groups had a 2% to 3% surgical risk per year after the first year.

CONCLUSIONS

Small bowel imaging at the time of diagnosis in pediatric CD can help predict the risk of small bowel surgical intervention and should be recommended for all newly diagnosed patients. Nearly one third of our cohort underwent small bowel surgical intervention through 8 years of follow-up. Surgical complications of CD often occur in the small bowel, and counseling families about surgical risk is an integral part of pediatric CD management.

The genetic burden of inflammatory bowel diseases: implications for the clinic?

Inflammatory bowel diseases (IBD), which include Crohn's disease (CD) and ulcerative colitis (UC), are characterized by chronic intestinal inflammation. Their etiology is multifactorial, with complex interactions between genetic and environmental factors, which are still largely unclear. Areas covered: The influence of genetics is clearly demonstrated by important epidemiological data, including familial aggregation and concordance in twins. In 2001, the first genetic susceptibility gene for IBD, the NOD2 gene, was identified. Currently, thanks to genetic wide association studies, over 200 susceptibility genetic markers are know. Expert commentary: However, clinically highly relevant gene associations are still very limited and the usefulness of these information in the current clinical strategies for treatment and surveillance of IBD is weak. Nevertheless, the recent identification of some genetic risk variants has clarified some newbiological pathways of these diseases thus paving the way for the discoveries in the near future of new targeted therapies.

The diagnostic accuracy of faecal calprotectin and small bowel capsule endoscopy and their correlation in suspected isolated small bowel Crohn's disease

INTRODUCTION

Faecal calprotectin (FC) is less accurate at identifying inflammation in the small bowel than in the colon. Small bowel capsule endoscopy (SBCE) is a useful tool to detect small bowel inflammation. We investigated the diagnostic accuracy of FC and SBCE and their correlation in patients with suspected isolated small bowel Crohn's disease.

PATIENTS AND METHODS

This was performed as a prospective single centre study including patients attending for SBCE with suspected small bowel Crohn's disease. Patient demographics, symptoms, medications and blood parameters were collected. Capsule endoscopy findings were analysed against calprotectin values, final diagnosis and blood parameters.

RESULTS

A total of 146 patients were included (99 females and 47 males) with a mean age of 38±14 years. FC of more than 50 mg/kg was not significantly associated with clinically relevant capsule endoscopy findings (P=0.25), correlation coefficient was 0.11. Sensitivity, specificity, positive and negative predictive values for FC at a cut-off of more than 50 mg/kg were 88.9% [95% confidence interval (CI): 65.3-98.6], 25.0% (95% CI: 17.8-33.4), 14.3 (95% CI: 8.4-22.2) and 94.1% (95% CI: 80.3-99.3), respectively. A raised FC was not significantly associated with an elevated C-reactive protein or the presence of anaemia (P=0.19 and 0.10, respectively).

CONCLUSION

FC performs modestly as a screening test to exclude small bowel inflammation. However, we recommend interpretation within the overall clinical context to avoid overlooking the infrequent patient with small bowel inflammation and a negative FC.

Serologic microbial associated markers can predict Crohn's disease behaviour years before disease diagnosis

BACKGROUND

Patients with Crohn's disease (CD) have serologic responses to various microbial antigens. Serologic markers are associated with aggressive forms of disease and can be detected before onset of symptoms. Their utility in pre-clinical disease or prediction of complicated disease course before diagnosis is unclear.

AIM

To evaluate the pattern of serologic anti-microbial antibodies long prior to diagnosis and the subsequent risk of complicated Crohn's disease at diagnosis.

METHODS

Sera from 100 US military personnel with Crohn's disease were obtained from the Department of Defense Serum Repository. For each patient, four samples were obtained at different time points before and around diagnosis, and were tested for 6 microbiota-directed antibodies (ASCA-IgA, ASCA-IgG, anti-OmpC, anti-CBir1, anti-A4-Fla2 and anti-FlaX). Associations between the presence and accumulation of Crohn's disease anti-microbial antibodies before diagnosis and with the later development of complications were evaluated.

RESULTS

Overall, 65 patients were positive for at least one Crohn's disease associated anti-microbial antibody in the earliest available sample, at a median of 6 years before Crohn's disease diagnosis (interquartile range, 5.6-8.2). The number of positive anti-microbial antibodies increased up to the time of Crohn's disease diagnosis. Complicated disease developed around the time of diagnosis in 24 patients. The proportion of positive antimicrobial antibodies before diagnosis was higher in patients with complicated vs. noncomplicated Crohn's disease. There was an inverse relationship between the time to first complication and the magnitude of serologic response before diagnosis.

CONCLUSION

The presence and accumulation of circulating anti-microbial antibodies years before Crohn's disease diagnosis was associated with complicated Crohn's disease at or shortly after diagnosis.

Genetics and Pathogenesis of Inflammatory Bowel Disease

We are currently in an exciting time when our understanding of genetic underpinnings of inflammatory bowel disease (IBD) has undergone a revolution, based in large part on novel genotyping and sequencing technologies. With >160 susceptible loci identified for IBD, the goal is now to understand at a fundamental level the function of these susceptibility alleles. Determining the clinical relevance of how these susceptible genes shape the development of IBD is also a high priority. The main challenge is to understand how the environment and microbiome play a role in triggering disease in genetically susceptible individuals, as the interactions may be complex. To advance the field, novel in vitro and mouse models that are designed to interrogate complex genetics and functionally test hypotheses are needed. Ultimately, the goal of genetics studies will be to translate genetics to patients with IBD and improve their care.

Biomarkers of intestinal fibrosis - one step towards clinical trials for stricturing inflammatory bowel disease

Intestinal fibrosis, caused by an excessive deposition of extracellular matrix components, and subsequent stricture development are a common complication of inflammatory bowel disease. However, currently there are no biomarkers which reliably predict the risk of developing intestinal strictures or identify early stages of fibrosis prior to clinical symptoms. Candidate biomarkers of intestinal fibrosis, including gene variants (i.e. nucleotide-binding oligomerization domain-2 gene), serum microRNAs (miR-19, miR-29), serum extracellular matrix proteins (i.e. collagen, fibronectin) or enzymes (i.e. tissue inhibitor of matrix metalloproteinase-1), serum growth factors (i.e. basic fibroblast growth factor, YKL-40), serum anti-microbial antibodies (i.e. anti-Saccharomyces cerevisiae) and circulating cells (i.e. fibrocytes) have shown conflicting results on relatively heterogeneous patients' cohorts, and none of them was proven to be strictly specific for fibrostenosis, but rather predictive of a disease disabling course. In this review we critically reassess the diagnostic and prognostic value of serum biomarkers of intestinal fibrosis in inflammatory bowel disease.

Defining Disease Severity in Inflammatory Bowel Diseases: Current and Future Directions

Although most treatment algorithms in inflammatory bowel disease (IBD) begin with classifying patients according to disease severity, no formal validated or consensus definitions of mild, moderate, or severe IBD currently exist. There are 3 main domains relevant to the evaluation of disease severity in IBD: impact of the disease on the patient, disease burden, and disease course. These measures are not mutually exclusive and the correlations and interactions between them are not necessarily proportionate. A comprehensive literature search was performed regarding current definitions of disease severity in both Crohn's disease and ulcerative colitis, and the ability to categorize disease severity in a particular patient. Although numerous assessment tools for symptoms, quality of life, patient-reported outcomes, fatigue, endoscopy, cross-sectional imaging, and histology (in ulcerative colitis) were identified, few have validated thresholds for categorizing disease activity or severity. Moving forward, we propose a preliminary set of criteria that could be used to classify IBD disease severity. These are grouped by the 3 domains of disease severity: impact of the disease on the patient (clinical symptoms, quality of life, fatigue, and disability); measurable inflammatory burden (C-reactive protein, mucosal lesions, upper gastrointestinal involvement, and disease extent), and disease course (including structural damage, history/extension of intestinal resection, perianal disease, number of flares, and extraintestinal manifestations). We further suggest that a disease severity classification should be developed and validated by an international group to develop a pragmatic means of identifying patients with severe disease. This is increasingly important to guide current therapeutic strategies for IBD and to develop treatment algorithms for clinical practice.

Systematic review: predicting and optimising response to anti-TNF therapy in Crohn's disease - algorithm for practical management

BACKGROUND

Nonresponse and loss of response to anti-TNF therapies in Crohn's disease represent significant clinical problems for which clear management guidelines are lacking.

AIM

To review the incidence, mechanisms and predictors of primary nonresponse and secondary loss of response to formulate practical clinical algorithms to guide management.

METHODS

Through a systematic literature review, 503 articles were identified which fit the inclusion criteria.

RESULTS

Primary nonresponse to anti-TNF treatment affects 13-40% of patients. Secondary loss of response to anti-TNF occurs in 23-46% of patients when determined according to dose intensification, and 5-13% of patients when gauged by drug discontinuation rates. Recent evidence suggests that the mechanisms underlying primary nonresponse and secondary loss of response are multifactorial and include disease characteristics (phenotype, location, severity); drug (pharmacokinetic, pharmacodynamic or immunogenicity) and treatment strategy (dosing regimen) related factors. Clinical algorithms that employ therapeutic drug monitoring (using anti-TNF tough levels and anti-drug antibody levels) may be used to determine the underlying cause of primary nonresponse and secondary loss of response respectively and guide clinicians as to which patients are most likely to respond to anti-TNF therapy and help optimise drug therapy for those who are losing response to anti-TNF therapy.

CONCLUSIONS

Nonresponse or loss of response to anti-TNF occurs commonly in Crohn's disease. Clinical algorithms utilising therapeutic drug monitoring may establish the mechanisms for treatment failure and help guide the subsequent therapeutic approach.

A validated web-based tool to display individualised Crohn's disease predicted outcomes based on clinical, serologic and genetic variables

BACKGROUND

Early treatment for Crohn's disease (CD) with immunomodulators and/or anti-TNF agents improves outcomes in comparison to a slower 'step up' algorithm. However, there remains a limited ability to identify those who would benefit most from early intensive therapy.

AIM

To develop a validated, individualised, web-based tool for patients and clinicians to visualise individualised risks for developing Crohn's disease complications.

METHODS

A well-characterised cohort of adult patients with CD was analysed. Available data included: demographics; clinical characteristics; serologic immune responses; NOD2 status; time from diagnosis to complication; and medication exposure. Cox proportional analyses were performed to model the probability of developing a CD complication over time. The Cox model was validated externally in two independent CD cohorts. Using system dynamics analysis (SDA), these results were transformed into a simple graphical web-based display to show patients their individualised probability of developing a complication over a 3-year period.

RESULTS

Two hundered and forty three CD patients were included in the final model of which 142 experienced a complication. Significant variables in the multivariate Cox model included small bowel disease (HR 2.12, CI 1.05-4.29), left colonic disease (HR 0.73, CI 0.49-1.09), perianal disease (HR 4.12, CI 1.01-16.88), ASCA (HR 1.35, CI 1.16-1.58), Cbir (HR 1.29, CI 1.07-1.55), ANCA (HR 0.77, CI 0.62-0.95), and the NOD2 frameshift mutation/SNP13 (HR 2.13, CI 1.33-3.40). The Harrell's C (concordance index for predictive accuracy of the model) = 0.73. When applied to the two external validation cohorts (adult n = 109, pediatric n = 392), the concordance index was 0.73 and 0.75, respectively, for adult and pediatric patients.

CONCLUSIONS

A validated, web-based tool has been developed to display an individualised predicted outcome for adult patients with Crohn's disease based on clinical, serologic and genetic variables. This tool can be used to help providers and patients make personalised decisions about treatment options.

Childhood Maltreatment Is Associated with Ulcerative Colitis but Not Crohn's Disease: Findings from a Population-based Study

BACKGROUND

Previous research suggests a link between childhood adversities and inflammatory bowel disease (IBD); however, study limitations prevent generalization of findings. To address this, the current study uses a Canadian population-based sample to investigate the relationship between 3 childhood adversities and 2 types of IBD while controlling for a range of factors.

METHODS

Secondary data analysis of a subsample of the nationally representative 2012 Canadian Community Health Survey-Mental Health consisted of those with no missing data on any of the variables of interest (n = 21,852). The survey response rate was 68.9%. This study used logistic regression to estimate odds ratios of 3 types of childhood adversities (physical abuse, sexual abuse, and witnessing parental domestic violence) separately for ulcerative colitis and Crohn's disease, each compared with those without IBD. The final model controls for sociodemographics, health behaviors, and mental health. The exposure was assessed by retrospective self-report, and the outcome was by self-report of a health professional diagnosis.

RESULTS

In a fully adjusted model, those who are physically (odds ratio = 2.28; confidence interval, 1.39-3.75) or sexually abused (odds ratio = 2.64; confidence interval, 1.61-4.33) during childhood had significantly higher odds of ulcerative colitis than their non-maltreated peers. No relationship is found between witnessing parental domestic violence and ulcerative colitis. None of the early adversities are significantly related to Crohn's disease.

CONCLUSIONS

Childhood physical and sexual abuse are related to ulcerative colitis, but not Crohn's disease. Future research that can address epigenetic and neuroendocrine factors should investigate pathways through which early adversities may translate into one type of IBD but not another.

Diagnostic and Prognostic Microbial Biomarkers in Inflammatory Bowel Diseases

The microbiome plays multifaceted roles in the pathogenesis of inflammatory bowel diseases (IBD). Accordingly, the clinical challenge of patient heterogeneity in disease phenotype and response to treatment should in part be addressed by biomarkers that detect the host response to microbiota, and the levels of microbial taxa and products eliciting the host response in susceptible individuals. Molecular analysis has revealed much evidence for microbial taxonomic membership and microbial products in association with IBD, but their utility as clinical biomarkers is still in its infancy. A rich area of progress has been the development and validation of host serologic microbial biomarkers, which have achieved a distinctive position in the diagnosis and prognosis in IBD, and as a template for defining other categories of microbial biomarkers in disease state and phenotype.

Overcoming difficulty in diagnosis and differential diagnosis of Crohn's disease: the potential role of serological and genetic tests

Crohn's disease (CD) represents a heterogeneous group of chronic inflammatory disorders with various phenotypes. Establishing a definite diagnosis of CD should be based upon a combined assessment of clinical, endoscopic, radiological and pathological features. Although segmental disease distribution, transmural inflammation and non-caseating epithelioid granulomas have been considered as a 'hallmarks' for CD, clear diagnosis of CD in some patients has been challenging, due to overlapping endoscopic, radiographic and histologic features with other inflammatory bowel disease-like conditions. Laboratory markers (serological and genetic tests) may provide additional clues for the diagnosis and differential diagnosis of CD. This review focuses on the application of the currently available serological and genomic markers and in diagnosis and differential diagnosis of CD.

Long-term Outcomes and Risk Factors for Reoperation After Surgical Treatment for Gastrointestinal Crohn Disease According to Anti-tumor Necrosis Factor-α Antibody Use: 35 Years of Experience at a Single Institute in Korea

PURPOSE

Crohn disease is characterized by high rates of recurrence and reoperations. However, few studies have investigated long-term surgical outcomes in Asian populations. We investigated risk factors for reoperation, particularly those associated with anti-tumor necrosis factor-α (anti-TNF-α) antibody use, and long-term follow-up results.

METHODS

We reviewed the records of 148 patients (100 males and 48 females) who underwent surgery for gastrointestinal Crohn disease and retrospectively analyzed long-term outcomes and risk factors.

RESULTS

The mean age at diagnosis was 28.8 years. Thirty-eight patients (25.7%) received monoclonal antibody treatment before reoperation. A small bowel and colon resection was most commonly performed (83 patients, 56.1%). The median follow-up was 149 months, during which 47 patients underwent reoperation. The median interval between the primary and the secondary surgeries was 65 months, with accumulated reoperation rates of 16.5%, 31.8%, and 57.2% after 5, 10, and 15 years, respectively. Obstruction was the most common indication for reoperation (37 patients, 25.0%). In a multivariable analysis, age <17 years at diagnosis (A1) (odds ratio [OR], 2.20; P = 0.023), penetrating behavior (B3) (OR, 4.39; P < 0.001), and no azathioprine use (OR, 2.87; P = 0.003) were associated with reoperation. Anti-TNF-α antibody use did not affect the reoperation rate (P = 0.767).

CONCLUSION

We showed a high reoperation rate regardless of treatment with anti-TNF-α antibody, which indicates that recurrent surgery is still needed to cure patients with gastrointestinal Crohn diseases. Younger age at primary operation, penetrating behavior, and no azathioprine use were significant factors associated with reoperation for gastrointestinal Crohn disease.

Is faecal calprotectin equally useful in all Crohn's disease locations? A prospective, comparative study

INTRODUCTION

There are data suggesting that the diagnostic usefulness of faecal calprotectin (FC) may vary depending on the Crohn's disease (CD) location. The aim of the study was to compare the diagnostic usefulness of FC in CD patients with different disease locations.

MATERIAL AND METHODS

We prospectively enrolled 120 CD patients in the study. Disease activity was assessed by using Crohn's Disease Activity Index (CDAI), biochemical markers, and endoscopic and radiographic methods. Faecal calprotectin concentration was assessed in single stool samples by using the ELISA method.

RESULTS

Among all patients, 54 (45%) had ileocolonic CD location, 44 (36.5%) had isolated small bowel location, and 22 (18.5%) had colonic CD location. FC correlated significantly with C-reactive protein concentration and endoscopic and radiographic activity among patients with isolated small bowel CD (p = 0.03, r = 0.32; p < 0.0001, r = 0.78; p = 0.03, r = 0.35; respectively) and with C-reactive protein and endoscopic activity in isolated colonic CD (p = 0.0009, r = 0.7; p = 0.0002, r = 0.78; respectively). CDAI and inflammatory biochemical markers did not correlate with endoscopic and radiographic assessment in small bowel CD. In patients with ileocolonic CD, FC correlated significantly with endoscopy (p = 0.006, r = 0.5), radiographic assessment (p = 0.04, r = 0.3), CDAI (p = 0.0006, r = 0.5) and the majority of biochemical markers.

CONCLUSIONS

Faecal calprotectin is a useful diagnostic marker in all CD patients. Although its usefulness in small bowel CD seems to be the lowest, it should be utilized particularly in this disease location because of the lack of other reliable, non-invasive diagnostic methods.

Systematic review: new serological markers (anti-glycan, anti-GP2, anti-GM-CSF Ab) in the prediction of IBD patient outcomes

Traditionally, IBD diagnosis is based on clinical, radiological, endoscopic, and histological criteria. Biomarkers are needed in cases of uncertain diagnosis, or to predict disease course and therapeutic response. No guideline recommends the detection of antibodies (including ASCA and ANCA) for diagnosis or prognosis of IBD to date. However, many recent data suggest the potential role of new serological markers (anti-glycan (ACCA, ALCA, AMCA, anti-L and anti-C), anti-GP2 and anti-GM-CSF Ab). This review focuses on clinical utility of these new serological markers in diagnosis, prognosis and therapeutic monitoring of IBD. Literature review of anti-glycan, anti-GP2 and anti-GM-CSF Ab and their impact on diagnosis, prognosis and prediction of therapeutic response was performed in PubMed/MEDLINE up to June 2014. Anti-glycan, anti-GP2 and anti-GM-CSF Ab are especially associated with CD and seem to be correlated with complicated disease phenotypes even if results differ between studies. Although anti-glycan Ab and anti-GP2 Ab have low sensitivity in diagnosis of IBD, they could identify a small number of CD patients not detected by other tests such as ASCA. Anti-glycan Abs are associated with a progression to a more severe disease course and a higher risk for IBD-related surgery. Anti-GP2 Ab could particularly contribute to better stratify cases of pouchitis. Anti-GM-CSF Ab seems to be correlated with disease activity and could help predict relapses. These new promising biomarkers could particularly be useful in stratification of patients according to disease phenotype and risk of complications. They could be a valuable aid in prediction of disease course and therapeutic response but more prospective studies are needed.

Who should receive biologic therapy for IBD?: The rationale for the application of a personalized approach

The therapeutic approach in inflammatory bowel disease has evolved to target end-organ inflammation to heal intestinal mucosa and avoid structural damage. Objective therapeutic monitoring is required to achieve this goal. Earlier intervention with biologic therapy has been shown, indirectly, to be associated with higher clinical response and remission rates. A personalized approach to risk stratification with consideration of key clinical factors and inflammatory biomarker concentrations is recommended when deciding whether or not to start a patient on biologic therapy.

Single-nucleotide polymorphisms in SLC22A23 are associated with ulcerative colitis in a Canadian white cohort

BACKGROUND

SLC22A23 is an orphan gene in the SLC22 family of organic membrane transporters, and its single-nucleotide polymorphism rs17309827-T was recently nominally associated with intestinal inflammation in a genome-wide association study. Other polymorphisms in the SLC22A23 gene have been associated with diseases with an inflammatory component, and polymorphisms in related genes in the SLC22 family have been repeatedly associated with inflammatory bowel disease (IBD).

OBJECTIVE

In a candidate-gene study using a well-phenotyped, highly monitored, Manitoban white cohort, we investigated whether variations in SLC22A23 were associated with intestinal inflammation.

DESIGN

Selected genetic variations were genotyped by using fluorescent-based assays or a polymerase chain reaction-restriction fragment length polymorphism analysis in 160 individuals with Crohn disease, 149 individuals with ulcerative colitis, and 142 healthy control subjects to determine genetic associations.

RESULTS

Homozygocity for single-nucleotide polymorphisms rs4959235-TT and rs950318-GG was associated with IBD, whereby 6% of patients (18 of 311 cases) carried these genotypes, but they were not seen in healthy controls.

CONCLUSION

Associations reported in this article add to the emerging evidence that SLC22A23 variants could modify IBD risk. However, the biology of the gene and impact of variations on the gene's functions need to be tested to validate a causative role.

How will insights from genetics translate to clinical practice in inflammatory bowel disease?

Inflammatory bowel disease, consisting of Crohn's disease and ulcerative colitis, is a chronic inflammatory disease of the gut, which arises through an excessive immune response to the normal gut flora in a genetically susceptible host. The disease affects predominantly young adults and due to its chronic and relapsing nature gives rise to a high disease burden both financially, physically and psychologically. Current therapy still cannot prevent the need for surgical intervention in more than half of IBD patients. Consequently, advances in IBD therapy are of high importance. Recently, several new forms of targeted therapy have been introduced, which should improve surgery-free prognosis of IBD patients. Recent identification of genetic risk variants for IBD has led to new insights into the biological mechanisms of the disease, which will, in the future, lead to new targeted therapy. In the meantime repositioning of drugs from biologically similar diseases towards IBD might lead to new IBD therapies.