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

Serum proteome signatures associated with ileal and colonic ulcers in Crohn's disease

At a clinical level, ileal and colonic Crohn's disease (CD) are considered as separate entities. These subphenotypes need to be better supported by biological data to develop personalised medicine in CD. To this end, we combined different technologies (proximity extension assay, selected reaction monitoring, and high-sensitivity turbidimetric immunoassay (hsCRP)) to measure 207 immune-related serum proteins in CD patients presenting no endoscopic lesions (endoscopic remission) (n = 23), isolated ileal ulcers (n = 17), or isolated colonic ulcers (n = 16). We showed that isolated ileal ulcers and isolated colonic ulcers were specifically associated with 6 and 18 serum proteins, respectively: (high level: JUN, CNTNAP2; low level: FCRL6, LTA, CLEC4A, NTF4); (high level: hsCRP, IL6, APCS, CFB, MBL2, IL7, IL17A, CCL19, CXCL10, CSF3, IL10, CLEC4G, MMP12, VEGFA; low level: CLEC3B, GSN, TNFSF12, TPSAB1). Isolated ileal ulcers and isolated colonic ulcers were detected by hsCRP with an area under the receiver operating characteristics curve of 0.64 (p-value = 0.07) and 0.77 (p-value = 0.001), respectively. We highlighted distinct serum proteome profiles associated with ileal and colonic ulcers in CD, this finding might support the development of therapeutics and biomarkers tailored to disease location. SIGNIFICANCE: Although ileal and colonic Crohn's disease present important clinical differences (eg, progression, response to treatment and reliability of biomarkers), these two entities are managed with the same therapeutic strategy. The biological specificities of ileal and colonic Crohn's disease need to be better characterised to develop more personalised approaches. The present study used robust technologies (selected reaction monitoring, proximity extension assays and turbidimetric immunoassay) to quantify precisely 207 serum immune-related proteins in three groups of Crohn's disease patients presenting: 1) no endoscopic lesions (endoscopic remission) (n = 23); 2) isolated ileal ulcers (n = 17); 3) isolated colonic ulcers (n = 16). We found distinct serum proteome signatures associated with ileal and colonic ulcers. Our findings could foster the development of biomarkers and treatments tailored to Crohn's disease location.

Fecal calprotectin in pediatric gastrointestinal diseases: Pros and cons

BACKGROUND

Fecal calprotectin is a valuable biomarker for assessing intestinal inflammation in pediatric gastrointestinal diseases. However, its role, pros, and cons in various conditions must be comprehensively elucidated.

AIM

To explore the role of fecal calprotectin in pediatric gastrointestinal diseases, including its advantages and limitations.

METHODS

A comprehensive search was conducted on PubMed, PubMed Central, Google Scholar, and other scientific research engines until February 24, 2024. The review included 88 research articles, 56 review articles, six meta-analyses, two systematic reviews, two consensus papers, and two letters to the editors.

RESULTS

Fecal calprotectin is a non-invasive marker for detecting intestinal inflammation and monitoring disease activity in pediatric conditions such as functional gastrointestinal disorders, inflammatory bowel disease, coeliac disease, coronavirus disease 2019-induced gastrointestinal disorders, gastroenteritis, and cystic fibrosis-associated intestinal pathology. However, its lack of specificity and susceptibility to various confounding factors pose challenges in interpretation. Despite these limitations, fecal calprotectin offers significant advantages in diagnosing, monitoring, and managing pediatric gastrointestinal diseases.

CONCLUSION

Fecal calprotectin holds promise as a valuable tool in pediatric gastroenterology, offering insights into disease activity, treatment response, and prognosis. Standardized protocols and guidelines are needed to optimize its clinical utility and mitigate interpretation challenges. Further research is warranted to address the identified limitations and enhance our understanding of fecal calprotectin in pediatric gastrointestinal diseases.

Tight control using fecal calprotectin and early disease intervention increase the rates of transmural remission in Crohn's disease

BACKGROUND

Increasing evidence supports the use of transmural remission as a treatment target in Crohn's disease (CD), but it is seldom achieved in clinical practice. Tight monitoring of inflammation using fecal calprotectin with reactive treatment escalation may potentially improve these results.

AIMS

To evaluate if treatment escalation based on fecal calprotectin can improve the rates of transmural remission in CD. The influence of the timing of intervention on this strategy was also evaluated.

METHODS

Retrospective cohort study including 256 CD patients with 2 consecutive assessments by MRI-enterography and colonoscopy and with regular monitoring using fecal calprotectin. For each occurrence of an elevated fecal calprotectin (≥250 μg/g), we evaluated whether a reactive adjustment of medical treatment was performed. The ratio of treatment escalation/elevated fecal calprotectin was correlated with the chances of reaching transmural remission. Early disease was defined as disease duration <18 months without previous exposure to immunomodulators and biologics.

RESULTS

After a median follow-up of 2 years (IQR 1-4), 61 patients (23.8%) reached transmural remission. Ratios of escalation ≥50% resulted in higher rates of transmural remission (34.2% vs. 15.1%, p < 0.001). The effect was more pronounced in patients with early disease (50.0% vs. 12.0%, p = 0.003). In multivariate analysis, a treatment escalation ratio ≥50% (OR 3.46, 95% CI 1.67-7.17, p = 0.001) and early disease intervention (OR 3.24, 95% CI 1.12-9.34, p = 0.030) were independent predictors of achieving transmural remission.

CONCLUSION

Tight-monitoring and reactive treatment escalation increase the rates of transmural remission in CD. Intervention in early disease further improves these results.

Inflammatory bowel disease: recent developments

Paediatric-onset inflammatory bowel disease (IBD) is a complex and heterogenous condition. Incidence of disease in those aged <18 years has doubled over the last 25 years, with concurrent increased prevalence and no decrease in disease severity. The tools available at diagnosis for investigation have developed over the last 10 years, including better utilisation of faecal calprotectin, improved small bowel imaging and video capsule endoscopy. Alongside this, management options have increased and include biological and small molecule therapies targeting alternative pathways (such as interleukin 12/23, integrins and Janus kinase/signal transducers and activators of transcription, JAK-STAT pathways) and better understanding of therapeutic drug monitoring for more established agents, such as infliximab. Dietary manipulation remains an interesting but contentious topic.This review summarises some of the recent developments in the diagnosis, investigation and management of IBD in children and young people. IBD is increasingly recognised as a continuum of disease, with a proportion of patients presenting with classical Crohn's disease or ulcerative colitis phenotypes. Future implementation of personalisation and stratification strategies, including clinical and molecular biomarkers, implementation of predictors of response and outcome and use of additional therapies, will continue to require working within clinical networks and multiprofessional teams.

Quantification of Enteric Dysfunction in Cystic Fibrosis: Inter- and Intraindividual Variability

OBJECTIVES

To test the utility of various biomarkers as indicators of gut dysfunction in cystic fibrosis (CF) and determine whether intraindividual variations in these measures are repeatable over short intervals and whether interindividual variations correlate with clinical outcomes.

STUDY DESIGN

We performed a cross-sectional, limited longitudinal study of children with CF aged 1-21 years who provided blood and stool samples at 2 or 3 visits, 2 weeks and 3 months apart, which were assayed for markers of intestinal inflammation (fecal calprotectin [fCal], lipocalin-2 [fLcn2], neopterin), and permeability (plasma lipopolysaccharide [LPS] antibodies, LPS-binding protein) by enzyme immunoassays. Control specimens were obtained from children without CF who had undergone esophagogastroduodenoscopy and had no evidence of gut inflammation.

RESULTS

Twenty-six of 29 participants with CF completed the study. Sixty-nine stools (57 case/12 control) and 76 plasmas (60 case/16 control) were analyzed. LPS antibody had reliable intraindividual stability. fCal, fLcn2, and neopterin were significantly greater in CF than in control samples. fCal was negatively correlated with 3-month interval change (Δ) in weight-for-age z-score, body mass index/weight-for-length z-score, and forced expiratory volume in 1 second. fLcn2 was negatively correlated with FEV1 but not with anthropometrics. No marker correlated with Δbody mass index/weight-for-length z-score or ΔFEV1.

CONCLUSIONS

fLcn2 is elevated in people with CF and might predict worse interval pulmonary function. Expanded studies are warranted to test if fLcn2 correlates with changes in additional outcomes.

Clinical Value of Detecting Fecal Calprotectin by Using Colloidal Gold Assay in Screening or Diagnosing Crohn's Disease

Background

Crohn's disease (CD) is a chronic inflammatory disease, and its incidence is gradually increasing. Thus, the use of a simple and convenient examination method to detect CD in the natural population as early as possible is crucial. This study is aimed at using the colloidal gold semiquantitative assay to detect fecal calprotectin (FCP) and determine whether it is helpful in screening or diagnosing CD.

Methods

Using a prospectively maintained database, 59 patients with CD were analyzed using FCP measurement. Subsequently, 76 patients and 89 healthy individuals were assigned to the gastrointestinal dysfunction and control groups, respectively. To aid in the screening or diagnosis of CD, the receiver operating characteristic curve was used to determine the diagnostic efficacy of FCP thresholds. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were presented with 95% confidence intervals (CIs).

Results

Patients with CD showed significantly higher FCP levels. Compared with the healthy population, when the FCP level cut-off was 15 μg/g and 60 μg/g, the sensitivity, specificity, PPV, and NPV for CD diagnosis were 98.3% (CI, 95.0%-100%) and 78.0% (CI, 67.4-88.6%), 84.3% (CI, 76.7%-91.8%) and 98.9% (CI, 96.7%-100%), 80.6% (CI, 71.5%-89.7%) and 97.9% (CI, 93.7%-100%), and 98.7% (CI, 96.2%-100%) and 87.1% (CI, 80.6%-93.6%), respectively. The AUCs were 0.969 (CI, 0.941-0.997). Compared with the gastrointestinal dysfunction group, using the same FCP level cut-off, the sensitivity, specificity, PPV, and NPV for CD diagnosis were 98.3% (CI, 95.0%-100%) and 78.0% (CI, 67.4%-88.6%), 71.1% (CI, 60.9%-81.3%) and 89.5% (CI, 82.3%-96.7%), 72.5% (CI, 62.7%-82.3%) and 85.2% (CI, 75.7%-94.7%), and 98.1% (CI, 94.5%-100%) and 84.0% (CI, 76.0%-92.0%), respectively. The AUCs were 0.908 (CI, 0.856-0.960).

Conclusion

Detecting FCP by using the colloidal gold semiquantitative assay can be effective in screening and adjunct diagnosing of CD.

Defining Biological Remission in Crohn's Disease: Interest, Challenges and Future Directions

In Crohn's disease, the treat-to-target strategy has been greatly encouraged and has become a standard of care. In this context, defining the target [remission] constitutes a major stake and is fuelling the literature. Currently, clinical remission [symptom control] is no longer the only objective of treatments since it does not allow to closely control inflammation-induced tissue damage. The introduction of endoscopic remission as a therapeutic target clearly represented progress but this examination remains invasive, costly, not well accepted by patients and does not allow tight control of disease activity. More fundamentally, morphological techniques [e.g. endoscopy, histology, ultrasonography] are limited since they do not evaluate the biological activity of the disease but only its consequences. Besides, emerging evidence suggests that biological signs of disease activity could better guide treatment decisions than clinical parameters. In this context, we stress the necessity to define a novel treatment target: biological remission. Based on our previous work, we propose a conceptual definition of biological remission which goes beyond the classical normalization of inflammatory markers [C-reactive protein and faecal calprotectin]: absence of biological signs associated with the risk of short-term relapse and mid-/long-term relapse. The risk of short-term relapse seems essentially to be characterized by a persistent inflammatory state while the risk of mid-/long-term relapse implies a more heterogeneous biology. We discuss the value of our proposal [guiding treatment maintenance, escalation or de-escalation] but also the fact that its clinical implementation would require overcoming major challenges. Finally, future directions are proposed to better define biological remission.

Development of a multimodal machine-learning fusion model to non-invasively assess ileal Crohn's disease endoscopic activity

BACKGROUND AND OBJECTIVE

Recurrent attentive non-invasive observation of intestinal inflammation is essential for the proper management of Crohn's disease (CD). The goal of this study was to develop and evaluate a multi-modal machine-learning (ML) model to assess ileal CD endoscopic activity by integrating information from Magnetic Resonance Enterography (MRE) and biochemical biomarkers.

METHODS

We obtained MRE, biochemical and ileocolonoscopy data from the multi-center ImageKids study database. We developed an optimized multimodal fusion ML model to non-invasively assess terminal ileum (TI) endoscopic disease activity in CD from MRE data. We determined the most informative features for model development using a permutation feature importance technique. We assessed model performance in comparison to the clinically recommended linear-regression MRE model in an experimental setup that consisted of stratified 2-fold validation, repeated 50 times, with the ileocolonoscopy-based Simple Endoscopic Score for CD at the TI (TI SES-CD) as a reference. We used the predictions' mean-squared-error (MSE) and the receiver operation characteristics (ROC) area under curve (AUC) for active disease classification (TI SEC-CD≥3) as performance metrics.

RESULTS

121 subjects out of the 240 subjects in the ImageKids study cohort had all required information (Non-active CD: 62 [51%], active CD: 59 [49%]). Length of disease segment and normalized biochemical biomarkers were the most informative features. The optimized fusion model performed better than the clinically recommended model determined by both a better median test MSE distribution (7.73 vs. 8.8, Wilcoxon test, p<1e-5) and a better aggregated AUC over the folds (0.84 vs. 0.8, DeLong's test, p<1e-9).

CONCLUSIONS

Optimized ML models for ileal CD endoscopic activity assessment have the potential to enable accurate and non-invasive attentive observation of intestinal inflammation in CD patients. The presented model is available at https://tcml-bme.github.io/ML_SESCD.html.

Saudi Arabia consensus guidance for the diagnosis and management of adults with inflammatory bowel disease

Optimal management of inflammatory bowel disease (IBD) relies on a clear understanding and tailoring evidence-based interventions by clinicians in partnership with patients. This article provides concise guidelines for the management of IBD in adults, based on the most up-to-date information at the time of writing and will be regularly updated. These guidelines were developed by the Saudi Ministry of Health in collaboration with the Saudi Gastroenterology Association and the Saudi Society of Clinical Pharmacy. After an extensive literature review, 78 evidence-and expert opinion-based recommendations for diagnosing and treating ulcerative colitis and Crohn's disease in adults were proposed and further refined by a voting process. The consensus guidelines include the finally agreed on statements with their level of evidence covering different aspects of IBD diagnosis and treatment.

Fecal Calprotectin for Small Bowel Crohn's Disease: Is It a Cutoff Issue?

(1) Background: Fecal calprotectin (FC) correlates well with colonic inflammatory activity of Crohn’s disease (CD); data about relation of FC and small bowel (SB) lesions are still contradictory. The main aim was to analyze the relationship between FC levels and SB inflammatory activity in patients with established or suspected Crohn’s disease, assessed by small bowel capsule endoscopy (SBCE) or magnetic resonance enterography (MRE). (2) Methods: Two cohorts of patients were included: 1. Prospective data were collected from patients with established or suspected CD who underwent SBCE and FC (Cohort A); 2. A retrospective cohort of patients who underwent MRE and FC determination (Cohort B). Different cutoffs for FC were tested in both cohorts. (3) Results: 83 patients were included and 66 were finally analyzed. A total of 69.6% had SB lesions seen by SBCE (n = 25) or MRE (n = 21). FC mean levels were 605.74 + 607.07 μg/g (IQ range: 99.00−878.75), being significantly higher in patients with SB lesions compared to patients without lesions (735.91 + 639.70 μg/g (IQ range: 107.75−1366.25) vs. 306.35 + 395.26 μg/g (IQ range: 78.25−411.0), p < 0.005). For cohort A, 25 out of 35 patients had SB lesions and a significant correlation between Lewis Score and FC levels was achieved (R2: 0.34; p = 0.04). FC sensitivity (S), specificity (E), positive predictive value (PPV), and negative predictive values (NPV) for predicting SB lesions were 80%, 50%, 80%, and 50%, respectively, for FC > 100 µg/g. For cohort B, inflammatory SB activity, measured by MaRIA score, was detected in 21 out of 31 patients (67.7%). Patients with positive findings in MRE had significantly higher values of FC than those with no lesions (944.9 + 672.1 µg/g vs. 221 + 212.2 µg/g, p < 0.05). S, E, PPV, and NPV of FC were 89%, 50%, 77.2%, and 71.4% for FC levels > 100 µg/g. The higher sensitivity and specificity of the FC levels for the detection of SB lesions with SBCE and MRE was obtained for an FC cutoff >265 μg/g and >430 μg/g, respectively. (4) Conclusions: FC has a good correlation with the presence of SB lesions, assessed by SBCE and MRE, in patients with established or suspected Crohn’s disease. However, the ideal cutoff is here proven to be higher than previously reported. Multicenter and large prospective studies are needed in order to establish definitive FC cutoff levels.

Ultrasonographic scores for ileal Crohn's disease assessment: Better, worse or the same as contrast-enhanced ultrasound?

BACKGROUND

Intestinal ultrasound (IUS) is an increasingly used non-invasive tool to evaluate Crohn's disease (CD) activity. Recently, two IUS scores that evaluate inflammatory activity have emerged: the Simple Ultrasound Activity Score for CD (SUS-CD) and the International Bowel Ultrasound Segmental Activity Score (IBUS-SAS). We aimed to compare the accuracy of SUS-CD, IBUS-SAS and contrast-enhanced ultrasound (CEUS) in predicting inflammatory activity in the terminal ileum in ileocolonoscopy in CD patients.

METHODS

Retrospective study including all consecutive CD patients submitted to IUS with CEUS directed to the terminal ileum performed by a single operator between April 2016 and March 2020. Segmental SUS-CD and IBUS-SAS were calculated. A time-intensity curve of the contrast bowel wall enhancement was created with measurement of peak intensity using CEUS. The CD endoscopic activity in ileocolonoscopy was graded by Simple Endoscopic Score for CD (SES-CD) as inactive (SES-CD < 7) or active (SES-CD ≥ 7).

RESULTS

Fifty patients were included, 54.0% were female, with mean age of 34 ± 12 years, and most had isolated ileal disease (60.0%), and a nonstricturing, nonpenetrating behaviour (44.0%). Most of the patients (60.0%) had active endoscopic disease (SES-CD ≥ 7). SUS-CD and IBUS-SAS were not different between patients with active or inactive endoscopic disease (p = 0.15; 0.57, respectively), having a poor accuracy to correlate endoscopic activity (area under de curve (AUC) 0.62; 0.55, respectively). Peak intensity in CEUS was significantly different in patients with active or inactive endoscopic disease (p = 0.004), having a good accuracy to correlate endoscopic activity (AUC 0.80).

CONCLUSION

Unlike CEUS, SUS-CD and IBUS-SAS were not able to accurately correlate endoscopic activity in terminal ileum in CD. Therefore, CEUS is a non-invasive emerging method that should be increasingly integrated in the ultrasonographic evaluation of CD patients.

Clinical features of 44 patients with small bowel Crohns disease

OBJECTIVES

At present, there are many studies on Crohn's disease of terminal ileum and colon, but few studies on Crohn's disease of small intestine alone. This study aims to analyze the clinical features and therapeutic effect of small bowel in adult patients with Crohn's disease so as to strengthen the diagnosis and treatment for this disease.

METHODS

From July 1, 2015 to October 31, 2018, patients with small bowel Crohn's disease at Department of Gastroenterology, Third Xiangya Hospital of Central South University, were enrolled. At the same time, patients' demographics and clinical data were collected.

RESULTS

A total of 44 patients were small bowel Crohn's disease. Among them, 40 patients were male. The age at diagnosis was (35.8±10.3) years old and disease duration was (35.2±59.5) months. The subtypes included 29(65.9%) of ileum, 7(15.9%) of jejunum, 8(18.2%) of ileum with jejunum. There were 27(61.4%) of stricture behavior, 4(9.1%) of penetrating behavior, and 13(29.5%) of non-stricture and non-penetrating behavior. Endoscopic visible stricture (29/85, 34.1%) was common, followed by longitudinal ulcers (27/85, 31.8%). Non-caseate granulomatous were found in 2 cases (4.5%). The score of Crohn's disease activity index was correlated to hemoglobin, hematocrit, and erythrocyte sedimentation rate (all P<0.05). Among the most common symptom of abdominal pain (34/44, 77.3%), 11 patients (25.0%) developed complications (eg. intestinal obstruction) during the follow-up, and 66.7% of patients treated with mesalazine had complications.

CONCLUSIONS

Patients with ileum account for a large proportion in patients with small bowel Crohn's disease. Stricture is more common in small bowel Crohn's disease. Stricture and longitudinal ulcer are more common under enteroscopy. Crohn's disease activity index is correlated to hemoglobin, red blood cell specific volume, and erythrocyte sedimentation rate. The most common complication is intestinal obstruction. Mesalazine is less effective on small bowel Crohn's disease.

Diagnostic Accuracy of Fecal Calprotectin for the Detection of Small Bowel Crohn's Disease through Capsule Endoscopy: An Updated Meta-Analysis and Systematic Review

Background/Aims

The diagnosis of small bowel Crohn's disease with negative ileocolonoscopic findings has been challenging. Fecal calprotectin (FC) has been used to detect colonic inflammation, but its efficacy for detecting small bowel inflammation is less established. We performed an updated meta-analysis to evaluate the diagnostic accuracy of FC to detect active small bowel inflammation observed during capsule endoscopy.

Methods

We conducted a systematic literature search for studies that evaluated the correlation between small bowel inflammation and FC in patients with suspected/established Crohn's disease. We calculated the pooled sensitivity, specificity, and diagnostic odds ratios (DORs) and constructed hierarchical summary receiver operating characteristic curves for FC cutoffs of 50, 100, and 200 μg/g.

Results

Fourteen studies were eligible for the final analysis. The DORs of all FC cutoffs were significant. The highest DOR was observed at 100 μg/g (sensitivity, 0.73; specificity, 0.73; and DOR, 7.89) and was suggested as the optimal diagnostic cutoff. If we analyzed only studies that included patients with suspected Crohn's disease, the DOR was 8.96. If we analyzed only studies that included patients with a Lewis score ≥135 as a diagnostic criterion for active disease, the DOR was 10.90.

Conclusions

FC has significant diagnostic accuracy for detecting small bowel inflammation, and an FC cutoff of 100 μg/g can be used as a tool to screen for small bowel Crohn's disease.

Review article: distinctions between ileal and colonic Crohn's disease: from physiology to pathology

BACKGROUND

Ileal and colonic Crohn's disease seem to be two separate entities.

AIMS

To describe the main physiological distinctions between the small and the large intestine and to analyse the differences between ileal and colonic Crohn's disease.

METHODS

The relevant literature was critically examined and synthesised.

RESULTS

The small and large intestine have fundamental distinctions (anatomy, cellular populations, immune defence, microbiota). The differences between ileal and colonic Crohn's disease are highlighted by a heterogeneous body of evidence including clinical features (natural history of the disease, efficacy of treatments, and monitoring), epidemiological data (smoking status, age, gender) and biological data (genetics, microbiota, immunity, mesenteric fat). However, the contribution of these factors to disease location remains poorly understood.

CONCLUSION

The classification of ileal and colonic Crohn's disease as distinct subphenotypes is well supported by the literature. Understanding of these differences could be exploited to develop more individualised patient care.

Role of capsule endoscopy in inflammatory bowel disease: Anything new?

Capsule endoscopy (CE) is a recently developed diagnostic method for diseases of the small bowel that is non-invasive, safe, and highly tolerable. Its role in patients with inflammatory bowel disease has been widely validated in suspected and established Crohn’s disease (CD) due to its ability to assess superficial lesions not detected by cross-sectional imaging and proximal lesions of the small bowel not evaluable by ileocolonoscopy. Because CE is a highly sensitive but less specific technique, differential diagnoses that can simulate CD must be considered, and its interpretation should be supported by other clinical and laboratory indicators. The use of validated scoring systems to characterize and estimate lesion severity (Lewis score, Capsule Endoscopy Crohn’s Disease Activity Index), as well as the standardization of the language used to define the lesions (Delphi Consensus), have reduced the interobserver variability in CE reading observed in clinical practice, allowing for the optimization of diagnoses and clinical management strategies. The appearance of the panenteric CE, the incorporation of artificial intelligence, magnetically-guided capsules, and tissue biopsies are elements that contribute to CE being a promising, unique diagnostic tool in digestive tract diseases.

Experimental infectious challenge in pigs leads to elevated fecal calprotectin levels following colitis, but not enteritis

BACKGROUND

Fecal calprotectin is largely applied as a non-invasive intestinal inflammation biomarker in human medicine. Previous studies in pigs investigated the levels of fecal calprotectin in healthy animals only. Thus, there is a knowledge gap regarding its application during infectious diarrhea. This study investigated the usefulness of fecal calprotectin as a biomarker of intestinal inflammation in Brachyspira hyodysenteriae and Salmonella Typhimurium infected pigs.

RESULTS

Fecal samples from pigs with colitis (n = 18) were collected from animals experimentally inoculated with B. hyodysenteriae (n = 8) or from sham-inoculated controls (n = 3). Fecal samples from pigs with enteritis (n = 14) were collected from animals inoculated with Salmonella enterica serovar Typhimurium (n = 8) or from sham-inoculated controls (n = 4). For both groups, fecal samples were scored as: 0 = normal; 1 = soft, wet cement; 2 = watery feces; 3 = mucoid diarrhea; and 4 = bloody diarrhea. Fecal calprotectin levels were assayed using a sandwich ELISA, a turbidimetric immunoassay and a point-of-care dipstick test. Fecal calprotectin levels were greater in colitis samples scoring 4 versus ≤ 4 using ELISA, and in feces scoring 3 and 4 versus ≤ 1 using immunoturbidimetry (P < 0.05). No differences were found in calprotectin concentration among fecal scores for enteritis samples, regardless of the assay used. All samples were found below detection limits using the dipstick method.

CONCLUSIONS

Fecal calprotectin levels are increased following the development of colitis, but do not significantly change due to enteritis. While practical, the use of commercially available human kits present sensitivity limitations. Further studies are needed to validate the field application of calprotectin as a marker of intestinal inflammation.

Predicting disease course in ulcerative colitis using stool proteins identified through an aptamer-based screen

In the search for improved stool biomarkers for inflammatory bowel disease (IBD), an aptamer-based screen of 1129 stool proteins was conducted using stool samples from an IBD cohort. Here we report that of the 20 proteins subsequently validated by ELISA, stool Ferritin, Fibrinogen, Haptoglobin, Hemoglobin, Lipocalin-2, MMP-12, MMP-9, Myeloperoxidase, PGRP-S, Properdin, Resistin, Serpin A4, and TIMP-1 are significantly elevated in both ulcerative colitis (UC) and Crohn's disease (CD) compared to controls. When tested in a longitudinal cohort of 50 UC patients at 4 time-points, fecal Fibrinogen, MMP-8, PGRP-S, and TIMP-2 show the strongest positive correlation with concurrent PUCAI and PGA scores and are superior to fecal calprotectin. Unlike fecal calprotectin, baseline stool Fibrinogen, MMP-12, PGRP-S, TIMP-1, and TIMP-2 can predict clinical remission at Week-4. Here we show that stool proteins identified using the comprehensive aptamer-based screen are superior to fecal calprotectin alone in disease monitoring and prediction in IBD.

Faecal Biomarkers in Inflammatory Bowel Diseases: Calprotectin Versus Lipocalin-2-a Comparative Study

BACKGROUND AND AIMS

Faecal biomarkers, particularly calprotectin [FCAL], have become important diagnostic and monitoring tools in inflammatory bowel diseases [IBD]. As FCAL is mainly produced by neutrophils, we hypothesised that faecal lipocalin-2 [FLCN2], also expressed by intestinal epithelial cells [IEC], could be beneficial in specific clinical situations.

METHODS

We compared clinical and endoscopic activity-related correlations between FCAL and FLCN2, assayed from the same sample, in a cohort of 132 patients (72 Crohn's disease [CD]) and 40 controls. A detailed analysis of cellular origins was done by confocal microscopy and flow cytometry. To evaluate the potential to detect low-grade inflammation, we studied faecal and tissue concentrations in a cohort with clinical, endoscopic, and histological remission.

RESULTS

There was an excellent correlation between FCAL and FLCN2 [rS = 0.87, p <0.001] and comparable sensitivity and specificity to predict clinical and endoscopic disease activity, with optimal thresholds for endoscopic activity of 73.4 and 1.98 µg/g in ulcerative colitis [UC] and 78.4 and 0.56 µg/g in Crohn's disease for FCAL and FLCN2, respectively. Strong co-expression of both proteins was observed in granulocytes and macrophages. IECs expressed LCN2 but not CAL. In our IBD cohort in deep remission neither FCAL nor FLCN2 was different from controls; yet mucosal LCN2 but not CAL expressions remained elevated in the rectum of UC and the ileum of CD patients.

CONCLUSIONS

This study corroborates the diagnostic equivalence of FLCN2 and FCAL in IBD. In remission, persistent mucosal overexpression renders LCN2 an attractive candidate for molecular inflammation warranting further investigation.

Usefulness of Testing for Fecal Calprotectin in Pediatric Gastroenterology Clinical Practice

Gastrointestinal tract symptoms such as abdominal pain, constipation, diarrhea, and fever are common reasons for which parents take children to the pediatrician. An increasing prevalence of chronic diseases of the gastrointestinal tract and a decrease in the median age of their onset indicate the need to search for new diagnostic methods for differentiating inflammatory bowel diseases (IBDs) from other gastrointestinal tract diseases. An example of a novel biomarker is fecal calprotectin (FC), which is considered a noninvasive and useful marker of intestinal inflammation. This review summarizes currently available information on the use of FC in the diagnosis and monitoring of IBD in children. Additionally, it attempts to determine the course of action depending on the concentration of FC. Application of FC determination within the framework of primary medical care can decrease the number of children unnecessarily referred either to endoscopic or radiologic examination. There is a double advantage of calprotectin screening; for patients, it reduces delays in diagnosis and unnecessary exposure to endoscopy, and for doctors, it reduces pressure on endoscopy testing and facilitates decision-making. We emphasize the role of FC as a noninvasive marker, primarily in patients with IBD, in monitoring disease activity, predicting relapse, monitoring therapy efficacy, and monitoring postoperative relapses.

Ileal Transcriptomic Analysis in Paediatric Crohn's Disease Reveals IL17- and NOD-signalling Expression Signatures in Treatment-naïve Patients and Identifies Epithelial Cells Driving Differentially Expressed Genes

BACKGROUND AND AIMS

Crohn's disease [CD] arises through host-environment interaction. Abnormal gene expression results from disturbed pathway activation or response to bacteria. We aimed to determine activated pathways and driving cell types in paediatric CD.

METHODS

We employed contemporary targeted autoimmune RNA sequencing, in parallel to single-cell sequencing, to ileal tissue derived from paediatric CD and controls. Weighted gene co-expression network analysis [WGCNA] was performed and differentially expressed genes [DEGs] were determined. We integrated clinical data to determine co-expression modules associated with outcomes.

RESULTS

In all, 27 treatment-naive CD [TN-CD], 26 established CD patients and 17 controls were included. WGCNA revealed a 31-gene signature characterising TN-CD patients, but not established CD, nor controls. The CSF3R gene is a hub within this module and is key in neutrophil expansion and differentiation. Antimicrobial genes, including S100A12 and the calprotectin subunit S100A9, were significantly upregulated in TN CD compared with controls [p = 2.61 x 10-15 and p = 9.13 x 10-14, respectively] and established CD [both p = 0.0055]. Gene-enrichment analysis confirmed upregulation of the IL17-, NOD- and Oncostatin-M-signalling pathways in TN-CD patients, identified in both WGCNA and DEG analyses. An upregulated gene signature was enriched for transcripts promoting Th17-cell differentiation and correlated with prolonged time to relapse [correlation-coefficient-0.36, p = 0.07]. Single-cell sequencing of TN-CD patients identified specialised epithelial cells driving differential expression of S100A9. Cell groups, determined by single-cell gene expression, demonstrated enrichment of IL17-signalling in monocytes and epithelial cells.

CONCLUSIONS

Ileal tissue from treatment-naïve paediatric patients is significantly upregulated for genes driving IL17-, NOD- and Oncostatin-M-signalling. This signal is driven by a distinct subset of epithelial cells expressing antimicrobial gene transcripts.

Treat-to-Target in Pediatric Inflammatory Bowel Disease: What Does the Evidence Say?

The traditional management of inflammatory bowel disease, based on treatment intensification guided by clinical activity alone, has been revised in the last 10 years and a treat-to-target approach has been proposed and is currently under evaluation as a disease-modifying strategy. Treat-to-target focuses on objective and scheduled measures to monitor intestinal damage, with consequent therapeutic adjustments in case of failure to achieve pre-defined targets. Identification of targets has been set out by the Selecting Therapeutic Targets in Inflammatory Bowel Disease (STRIDE) committee in 2015. Mucosal healing is universally accepted as the main target both in Crohn's disease and ulcerative colitis, given its proven association with better long-term outcomes than clinical remission alone. Equally important is to ensure patients' clinical remission and improve patient-reported outcomes. Transmural healing (for Crohn's disease) and histological remission (for ulcerative colitis), listed as adjunctive targets, are likely to become primary targets in the near future. The ultimate goal of this approach is to modify the natural history of inflammatory bowel diseases by trying to block bowel damage progression, with interventions in the pre-clinical stage. In this review, we will discuss the current recommended therapeutic targets, as well as those that are considered adjunctive targets, with a focus on the limited pediatric literature available. Prospective long-term trials are warranted in order to identify the most appropriate target for the pediatric population and its specific issues. Identification of reliable predictors of disease course, outcome, and response to treatment will help to individually adapt each step of this monitoring algorithm and consequent therapeutic decision.

Biochemical Biomarkers of Mucosal Healing for Inflammatory Bowel Disease in Adults

Mucosal healing (MH) is the key therapeutic target of inflammatory bowel disease (IBD). The evaluation of MH remains challenging, with endoscopy being the golden standard. We performed a comprehensive overview of the performance of fecal-, serum-, and urine-based biochemical markers in colonic IBD to find out whether we are ready to replace endoscopy with a non-invasive but equally accurate instrument. A Pubmed, Web of Knowledge, and Scopus search of original articles as potential MH markers in adults, published between January 2009 and March 2020, was conducted. Finally, 84 eligible studies were identified. The most frequently studied fecal marker was calprotectin (44 studies), with areas under the curves (AUCs) ranging from 0.70 to 0.99 in ulcerative colitis (UC) and from 0.70 to 0.94 in Crohn`s disease (CD), followed by lactoferrin (4 studies), matrix metalloproteinase-9 (3 studies), and lipocalin-2 (3 studies). The most frequently studied serum marker was C-reactive protein (30 studies), with AUCs ranging from 0.60 to 0.96 in UC and from 0.64 to 0.93 in CD. Fecal calprotectin is an accurate MH marker in IBD in adults; however, it cannot replace endoscopy and the application of calprotectin is hampered by the lack of standardization concerning the cut-off value. Other markers are either not sufficiently accurate or have not been studied extensively enough.

Biomarkers of disease activity and other factors as predictors of adalimumab pharmacokinetics in inflammatory bowel disease

Inflammatory bowel disease (IBD) is commonly treated with adalimumab. The main objective of the study was to develop a population pharmacokinetic model of adalimumab in IBD patients evaluating the potential biomarkers of disease activity and other factors and its implications in adalimumab dosing. A prospective observational study was performed in adult patients diagnosed with Crohn's disease and ulcerative colitis treated with adalimumab and following a proactive therapeutic drug monitoring of serum concentrations. Adalimumab serum concentrations (ASC) were quantified mainly prior the administration using an enzyme-linked immunosorbent assay (ELISA). A population pharmacokinetic model was developed based on 303 ASC data of 104 IBD patients using non-linear mixed effect modelling approach. Sixty-five ASC from 20 additional patients were randomly selected as an external validation group. A one-compartment model with first order absorption and elimination best describe the ASC time course. Body mass index (BMI), faecal calprotectin (FCP), unexplained decline in ASC and the specific administration pen device exhibited significant influence on apparent clearance (p-value < 0.001). FCP was the inflammatory activity biomarker showing the most relevant impact on adalimumab exposure, higher than C-reactive protein and albumin, and may be useful for adalimumab dosing adjustment. The population-based pharmacokinetic model developed adequately characterized adalimumab exposure in IBD patients. The unexplained decline in ASC, FCP, BMI and the specific administration pen device were identified as meaningful variables significantly influencing adalimumab pharmacokinetics.

Plasma calprotectin is superior to serum calprotectin as a biomarker of intestinal inflammation in ulcerative Colitis

Background and aims: Despite promising results, only a few studies have been published on serum calprotectin as a biomarker in IBD. Recently, plasma measurements of calprotectin have been shown to be more reliable than serum measurements. In this study, we aim to assess plasma and serum calprotectin measurements as biomarkers of disease activity in paediatric and adult ulcerative colitis.Methods: Paediatric (5-18 years) and adult (>18 years) patients scheduled for colonoscopy due to suspected or confirmed ulcerative colitis were included prospectively. Stool and blood samples were collected at time of colonoscopy and patient symptom scores were recorded. At colonoscopy the Ulcerative Colitis Endoscopic Index of Severity was recorded. Histology was graded according to the Geboes score.Results: 84 patients where included; 30 paediatric and 54 adult patients. Plasma calprotectin had a stronger correlation to all outcome variables than serum calprotectin. Plasma calprotectin correlated positively to disease extent (Rho = 0.53, p < .0001), symptoms scores (Rho = 0.54, p = .002, only in the paediatric cohort), endoscopic scores (Rho = 0.39, p = .0003), histological scores (Rho 0.28, p = .01) and, when using endoscopic assessment of severity as reference, could discriminate active disease from patients in remission (p = .03).Conclusions: While more studies are needed to assess if plasma calprotectin can discriminate healthy individuals from ulcerative colitis, this study indicates that plasma calprotectin can be used as a biomarker of disease activity, especially in cases where faecal calprotectin measurements are cumbersome either due to patient compliance or logistical requirements.

Faecal calprotectin delivers on convenience, cost reduction and clinical decision-making in inflammatory bowel disease: a real-world cohort study

BACKGROUND

Faecal calprotectin (FC) is an accurate biomarker of disease activity in inflammatory bowel disease (IBD), yet the cost/resource implications of incorporating FC into 'real-world' practice remain uncertain.

AIM

To evaluate the utility of FC in clinical decision-making and on healthcare costs in IBD.

METHODS

Retrospective data, including colonoscopy/other investigations, medication, admission and surgical data, were collected from hospital records and compared between two groups: pre-FC historical cohort (2005-2009) where colonoscopy was used to assess IBD activity versus the cohort where FC was used first instead (2010-2014). Post-test costs were also compared.

RESULTS

A total of 357 FC tests (246 patients, 2010-2014) and 450 colonoscopies (268 patients, 2005-2009) were performed. On subsequent review, both FC and colonoscopy (in their respective cohorts) were associated with changes in management in 50.7 versus 56.2% (P = 0.14), respectively, with similar proportions of subsequent IBD-related investigations within 6 months (21.8 vs 21.9%, P = 1.0). Prior to FC availability (2005-2009), a colonoscopy for disease reassessment cost AU$606 578 (cost per patient-year $1887.34) versus AU$282 048 (cost per patient-year $968.60) when FC ± colonoscopy was used (2010-2014). Within the FC cohort, 73.6% did not proceed to colonoscopy within 6 months post-FC, and 60.6% had not undergone colonoscopy post-FC by the end of follow up (median 1.8 years (0.1, 4.6) post-FC). Those with FC ≥ 250 were scoped earlier than those with FC < 100 μg/mL (median 0.49 vs 1.0 years, P = 0.03).

CONCLUSION

Introduction of FC into routine IBD care aided changes in clinical management in a similar proportion, yet at potentially half the total cost, compared to a historical colonoscopy-only cohort at the same centre.

Does fecal calprotectin equally and accurately measure disease activity in small bowel and large bowel Crohn's disease?: a systematic review

Fecal calprotectin (FC) is a highly sensitive disease activity biomarker in inflammatory bowel disease. However, there are conflicting reports on whether the diagnostic accuracy in Crohn's disease is influenced by disease location. The aim of this study was to undertake a systematic review of the published literature. Relevant databases were searched from inception to November 8, 2016 for cohort and case control studies which had data on FC in patients with isolated small bowel (SB) and large bowel (LB) Crohn's disease. Reference standards for disease activity were endoscopy, magnetic resonance imaging, computed tomography or a combination of these. The QUADAS-2 research tool was used to assess the risk of bias. There were 5,619 records identified at initial search. The 2,098 duplicates were removed and 3,521 records screened. Sixty-one full text articles were assessed for eligibility and 16 studies were included in the final review with sensitivities and specificities per disease location available from 8 studies. Sensitivities of FC at SB and LB locations ranged from 42.9% to 100% and 66.7% to 100% respectively while corresponding specificities were 50% to 100% and 28.6% to 100% respectively. The sensitivities and specificities of FC to accurately measure disease activity in Crohn's disease at different disease locations are diverse and no firm conclusion can be made. Better studies need to be undertaken to categorically answer the effect of disease location on the diagnostic accuracy of FC.

What is the role of C-reactive protein and fecal calprotectin in evaluating Crohn's disease activity?

Historically, the evaluation of patients with Crohn's disease (CD) has centered on use of subjective symptom-based assessment. However, patients with CD experience a broad spectrum of non-specific symptoms that may not directly correlate with objective measures of inflammation. Endoscopy has been the gold standard for evaluating the burden and severity of mucosal disease. However, use of ileocolonoscopy for disease monitoring in long-term follow-up is limited by considerations of cost, resource utilization, and invasiveness. As treatment goals in CD have shifted towards 'treat-to-target' paradigms that emphasize tight control of inflammation, it has become increasingly evident that sensitive, accurate, and reliable measures of disease activity are required. The use of non-invasive serum and fecal biomarkers such as C-reactive protein (CRP) and fecal calprotectin (FC) has been evaluated in patients with CD for categorizing disease activity, predicting treatment response, identifying patients at risk for disease relapse, and as a potential therapeutic target. In this review, we summarize the interpretation of CRP and FC in patients with CD within specific clinical contexts and according to assay performance characteristics.

Correlation of the endoscopic findings for small and large bowels in pediatric patients with established Crohn's disease

Small bowel capsule endoscopy can detect subtle mucosal lesions in pediatric patients with Crohn’s disease, and our aim was to evaluate its application in established ileocolonic Crohn’s disease. Colonic inflammation was evaluated with the colonic Simple Endoscopic Score for Crohn’s Disease (SES-CD) (excluding the score of the terminal ileum). Small bowel inflammation was evaluated with the Lewis score and/or Capsule Endoscopy Crohn’s Disease Activity Index (CECDAI). A Lewis score <135 was defined as small bowel inactive. A colonic SES-CD of 0 (colonic inactive group) was observed in 22/42 procedures (52.4%), and active small bowel lesions were observed in 11/22 procedures (50.0%). The Lewis score was lower in the colonic inactive group compared to the colonic active group. Correlations between the colonic SES-CD, the Lewis score and CECDAI were weak. The Lewis score and CECDAI in the colonic inactive group had significant correlation with fecal calprotectin levels. We suggest that Crohn’s disease patients without both colonic active lesions and elevation of fecal calprotectin levels may not need to receive small bowel capsule endoscopy due to low incidence of lesions in small bowel.

Fecal Calprotectin as a Selection Tool for Small Bowel Capsule Endoscopy in Suspected Crohn's Disease

BACKGROUND

Small bowel capsule endoscopy (SBCE) is a firstline examination in patients with suspected Crohn's disease (CD) after negative ileocolonoscopy. Fecal calprotectin (FC) is a noninvasive marker of intestinal inflammation. The aim of this study was to evaluate the predictive value of FC in inflammatory activity detected by SBCE in patients with suspected CD.

METHODS

This is a retrospective study including patients who underwent SBCE for suspected CD between March 2015 and October 2016. FC was measured within 1 week of SBCE. Inflammatory activity at SBCE was considered significant when the Lewis score (LS) was ≥135. FC correlation with LS was assessed using the Spearman correlation. The diagnostic accuracy of FC for significant inflammatory activity at SBCE was calculated by the area under the receiver operating characteristic curve (AUC).

RESULTS

Seventy-five patients were included: 52 females (69.3%), with a mean age of 37 years. SBCE detected significant inflammatory activity (LS ≥ 135) in 42 patients (56%), and FC was positively correlated to LS (rank correlation = 0.56; P < 0.001). The AUC of FC was 0.854 for significant inflammatory activity (LS ≥ 135). For values of FC ≥100 µg/g, an LS ≥135 was found in 33 of 37 patients (89.2%, P < 0.001), corresponding to a sensitivity, specificity, positive predictive value, and negative predictive value of 78.6%, 87.9%, 89.2%, and 76.3%, respectively.

CONCLUSIONS

FC has shown a good ability to predict significant inflammatory activity in SBCE in patients with suspected CD. Thus, FC proved to be a useful tool to select patients with suspected CD for SBCE.

Unsuspected Small-Bowel Crohn's Disease in Elderly Patients Diagnosed by Video Capsule Endoscopy

Background

Video capsule endoscopy (VCE) is increasingly performed among the elderly for obscure bleeding. Our aim was to report on the utility of VCE to uncover unsuspected Crohn's disease (CD) in elderly patients.

Methods

Retrospective review of VCE performed in elderly patients (≥70 y) at a tertiary hospital (2010-2015). All underwent prior negative bidirectional endoscopies. CD diagnosis was based on consistent endoscopic findings, exclusion of other causes, and a Lewis endoscopic score (LS) > 790 (moderate-to-severe inflammation). Those with lower LS (350-790) required histological confirmation. Known IBD cases were excluded.

Results

197 VCE were performed (mean age 78; range 70-93). Main indications were iron deficiency anemia (IDA), occult GI bleeding (OGIB), chronic abdominal pain, or diarrhea. Eight (4.1%) were diagnosed as CD based on the aforementioned criteria. Fecal calprotectin (FCP) was elevated in 7/8 (mean 580 μg/g). Mean LS was 1824. Small-bowel CD detected by VCE led to a change in management in 4/8. One patient had capsule retention secondary to NSAID induced stricture, requiring surgical retrieval.

Conclusions

VCE can be safely performed in the elderly. A proportion of cases may have unsuspected small-bowel CD despite negative endoscopies. FCP was the best screening test. Diagnosis frequently changed management.

Prognostic value of assessment of stool and serum IL-1β, IL-1ra and IL-6 concentrations in children with active and inactive ulcerative colitis

INTRODUCTION

Interleukin-1β (IL-1β), interleukin-1 receptor antagonist (IL-1ra) and interleukin-6 (IL-6) contribute to the pathogenesis of ulcerative colitis (UC). The aim of our study was to evaluate the serum and stool IL-1β, IL-1ra and IL-6 concentrations as potential prognostic factors in children with UC.

MATERIAL AND METHODS

Thirty-eight children with UC (20 active, 18 inactive) and 14 healthy controls were prospectively included in the study. IL-1β, IL-1ra and IL-6 concentrations were measured in serum and stool supernatants at inclusion to the study using ELISA immunoassays. The children were followed up over 5 years, and at each follow-up clinical disease activity, quantity and severity of relapses, nutritional status, endoscopic and histopathologic activity, disease complications and the treatment regimen were evaluated.

RESULTS

In children with active and inactive UC who had relapsed during a 5-year follow-up period compared to the non-relapse groups we found significantly increased serum IL-1β (1.34 vs. 0.98 pg/ml, p < 0.05, and 1.02 vs. 0.68 pg/ml, p < 0.01, respectively,) and IL-1ra (718.0 vs. 453.2 pg/ml, p < 0.05, and 567.4 vs. 365.1 pg/ml, p < 0.01, respectively). Additionally, in children who had experienced complications during a 5-year follow-up period we observed significantly increased serum and stool IL-1β (p < 0.05) and serum IL-1ra (p < 0.01) compared to the group without complications.

CONCLUSIONS

We concluded that serum IL-1β and IL-1ra and to a lesser extend stool IL-1β concentrations may be useful prognostic factors in children with active and inactive UC over a short-term follow-up period, which may help to identify children that require more aggressive therapy due to an increased risk of relapse or complications resulting from UC.

Infliximab and adalimumab drug levels in Crohn's disease: contrasting associations with disease activity and influencing factors

BACKGROUND

Discriminative drug level thresholds for disease activity endpoints in patients with Crohn's disease. have been consistently demonstrated with infliximab, but not adalimumab.

AIMS

To identify threshold concentrations for infliximab and adalimumab in Crohn's disease according to different disease endpoints, and factors that influence drug levels.

METHODS

We performed a cross-sectional service evaluation of patients receiving maintenance infliximab or adalimumab for Crohn's disease. Serum drug levels were at trough for infliximab and at any time point for adalimumab. Endpoints included Harvey-Bradshaw index, C-reactive protein and faecal calprotectin. 6-tioguanine nucleotide (TGN) concentrations were measured in patients treated with thiopurines.

RESULTS

A total of 191 patients (96 infliximab, 95 adalimumab) were included. Differences in infliximab levels were observed for clinical (P=.081) and biochemical remission (P=.003) and faecal calprotectin normalisation (P<.0001) with corresponding thresholds identified on ROC analysis of 1.5, 3.4 and 5.7 μg/mL. Adalimumab levels were similar between active disease and remission regardless of the endpoint assessed. Modelling identified that higher infliximab dose, body mass index and colonic disease independently accounted for 31% of the variation in infliximab levels, and weekly dosing, albumin and weight accounted for 23% of variation in adalimumab levels. TGN levels did not correlate with drug levels.

CONCLUSIONS

Infliximab drug levels are associated with the depth of response/remission in patients with Crohn's disease, but no such relationship was observed for adalimumab. More data are needed to explain the variation in drug levels.

Intra-patient variability in adalimumab drug levels within and between cycles in Crohn's disease

BACKGROUND

Whether therapeutic drug monitoring for adalimumab needs to be performed at trough has not been defined.

AIM

To determine intra-patient adalimumab drug-level variation and to identify modulating patient and disease factors.

METHODS

In this prospective observational study, adult patients with Crohn's disease established on maintenance adalimumab had drug levels measured repeatedly according to pre-defined schedules (visit 1: day 4-6, visit 2: day 7-9, trough: day 13-14) across two consecutive fortnightly cycles. Disease activity was assessed using Harvey-Bradshaw Index, C-reactive protein and faecal calprotectin. For this analysis, trough levels ≥4.9 μg/mL were considered therapeutic.

RESULTS

Nineteen patients underwent 111 evaluations. Mean intra-patient drug levels from paired visits between cycles did not differ (visit1 cycle1: 4.81, cycle2: 5.21 μg/mL, P = 0.24, visit2 cycle1: 4.86, cycle2: 4.82, P = 0.91 and trough cycle1: 3.95, cycle2: 3.95, P = 0.99), irrespective of disease activity. Drug levels were stable over the first 9 days (visit 1-2), but declined to trough by a mean 1.06 and 0.89 μg/mL between visit 1 or 2, respectively (P < 0.001). Models using nontemporal factors (smoking, syringe delivery device) and levels at earlier visits accounted for 66-80% of the variance in trough levels. On receiver-operating curve analysis, thresholds identified in the first 9 days that predicted a therapeutic trough level were similar to the trough threshold itself, with high sensitivity but modest specificity.

CONCLUSION

While therapeutic drug monitoring should be performed at trough, a drug level ≥4.9 μg/mL obtained during the first 9 days predicts a therapeutic trough drug level with reasonable confidence.

Trefoil factor-3 is not a useful marker of mucosal healing in Crohn's disease treated with anti-TNF-α antibodies

AIM

To evaluate whether repeated serum measurements of trefoil factor-3 (TFF-3) can reliably reflect mucosal healing (MH) in Crohn’s disease (CD) patients treated with anti-tumor necrosis factor-α (anti-TNF-α) antibodies.

METHODS

Serum TFF-3 was measured before and after anti-TNF-α induction therapy in 30 CD patients. The results were related to clinical, biochemical and endoscopic parameters. MH was defined as a ≥ 50% decrease in Simple Endoscopic Score for Crohn’s disease (SES-CD).

RESULTS

SES-CD correlated significantly with CD clinical activity and several standard biochemical parameters (albumin, leukocyte and platelet counts, C-reactive protein, erythrocyte sedimentation rate, fibrinogen). In contrast, SES-CD did not correlate with TFF-3 (P = 0.54). Moreover, TFF-3 levels did not change significantly after therapy irrespectively of whether the patients achieved MH or not. Likewise, TFF-3 did not correlate with changes in fecal calprotectin, which has been proposed as another biochemical marker of mucosal damage in CD.

CONCLUSION

Serum TFF-3 is not a convenient and reliable surrogate marker of MH during therapy with TNF-α antagonists in CD.

Fecal calprotectin for the prediction of small-bowel Crohn's disease by capsule endoscopy: a systematic review and meta-analysis

BACKGROUND AND AIMS

Fecal calprotectin is a well-established marker of mucosal inflammation. Although the correlation of elevated calprotectin levels with colonic inflammation has been confirmed repeatedly, it is less established for the small bowel. The aim of the current study was to assess the diagnostic accuracy of calprotectin for the prediction of active small-bowel disease on capsule endoscopy by performing a diagnostic test meta-analysis.

MATERIALS AND METHODS

A comprehensive search was performed using PubMed/Embase. Studies addressing patients with suspected/established Crohn's disease (CD) evaluated with calprotectin and videocapsule were included. A diagnostic meta-analysis was carried out; pooled diagnostic sensitivity, specificity, and diagnostic odds ratio (DOR) were calculated for each cut-off.

RESULTS

Seven studies (463 patients) were entered into the final analysis. The DOR was significant for all the evaluated FC cut-offs (50 μg/g: sensitivity 0.83, specificity 0.53, DOR-5.64; 100 μg/g: sensitivity 0.68, specificity 0.71, DOR-5.01; 200 μg/g: sensitivity 0.42, specificity 0.94, DOR-13.64). On sensitivity analyses, when only studies addressing suspected Crohn's or retrospective studies were included, the results did not change significantly. For studies including patients with suspected CD only, the overall accuracy for FC cut-off 50 μg/g was further increased (sensitivity 0.89, specificity 0.55, DOR-10.3), with a negative predictive value of 91.8%.

SUMMARY AND CONCLUSION

Fecal calprotectin has a significant diagnostic accuracy for the detection of small-bowel CD. Our results suggest that in patients with suspected CD with calprotectin <50 μg/g, the likelihood of positive diagnosis is very low.

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.

Association Between Fecal Calprotectin Levels and Small-bowel Inflammation Score in Capsule Endoscopy: A Multicenter Retrospective Study

BACKGROUND

Accurate inflammation reporting in capsule endoscopy (CE) is important for diagnosis and monitoring of treatment of inflammatory bowel disease (IBD). Fecal calprotectin (FC) is a highly specific biomarker of gut inflammation. Lewis score (LS) was developed to standardize quantification of inflammation in small-bowel (SB) CE images.

GOALS

Multicenter retrospective study aiming to investigate correlation between LS and FC in a large group of patients undergoing CE for suspected or known small-bowel IBD, and to develop a model for prediction of CE results (LS) based on FC levels.

STUDY

Five academic centers and a district general hospital offering CE in UK, Finland, Sweden, Canada, and Israel. In total, 333 patients were recruited. They had small-bowel CE and FC done within 3 months.

RESULTS

Overall, correlation between FC and LS was weak (r s: 0.232, P < 0.001). When two clinically significant FC thresholds (100 and 250 μg/g) were examined, the r s between FC and LS was 0.247 (weak) and 0.337 (moderate), respectively (P = 0.307). For clinically significant (LS ≥ 135) or negative (LS < 135) for SB inflammation, ROC curves gave an optimum cutoff point of FC 76 μg/g with sensitivity 0.59 and specificity 0.41.

LIMITATIONS

Retrospective design.

CONCLUSIONS

LS appears to show low correlation with FC as well as other serology markers of inflammation. FC does not appear to be a reliable biomarker for significant small-bowel inflammation. Nevertheless, FC level ≥ 76 μg/g may be associated with appreciable visual inflammation on small-bowel CE in patients with negative prior diagnostic workup.

Poor Correlation Between Clinical Disease Activity and Mucosal Inflammation, and the Role of Psychological Comorbidity, in Inflammatory Bowel Disease

OBJECTIVES

There is a move toward patient-reported outcome measures as end points in clinical trials of novel therapies for inflammatory bowel disease (IBD). However, the association between patient-reported symptoms and mucosal inflammation, and the influence of psychological factors, remains unclear. We examined this in a secondary care population.

METHODS

Validated patient-reported disease activity indices were used to define clinically active disease in a cohort of 356 patients with ulcerative colitis (UC) or Crohn's disease (CD). A fecal calprotectin ≥250 μg/g was used to define active mucosal inflammation. The hospital anxiety and depression scale (HADS) and patient health questionnaire (PHQ)-15 were used to assess for anxiety, depression, or somatization, respectively. Logistic regression analysis was performed to determine the association between symptoms, mucosal inflammation, and psychological comorbidity.

RESULTS

Clinical disease activity was associated with mucosal inflammation in UC (odds ratio (OR) 3.36; 95% confidence interval (CI) 1.34-8.47) but not in CD (OR 1.69; 95% CI 0.74-3.83). Depression in UC (OR 1.21 per 1-point increase in HADS; 95% CI 1.02-1.44) and somatization in UC (OR 1.17 per 1-point increase in PHQ-15; 95% CI 1.03-1.33) and CD (OR 1.31 per 1-point increase in PHQ-15; 95% CI 1.13-1.52) were associated with clinical disease activity. Overall, patient-reported symptoms yielded poor positive predictive values for mucosal inflammation in both CD and UC.

CONCLUSIONS

Patient-reported symptoms and the Harvey-Bradshaw index were poor predictors of mucosal inflammation in CD. Psychological comorbidity was associated with gastrointestinal symptom-reporting. A shift in the focus of IBD management toward one addressing both psychological and physical well-being is required.

Update on Orofacial Granulomatosis

Orofacial granulomatosis (OFG) is a condition manifesting clinically with chronic swelling of the mouth and/or face, notably with swelling of the lips and oral mucosa, a full-thickness, erythematous gingivitis and mucosal ulceration of various clinical types. Some patients may also present with neurological findings, for example facial palsy. Biopsy of affected tissue shows lymphoedema, with or without granulomatous inflammation. The oral lesions in OFG are histologically indistinguishable from the oral lesions in Crohn's disease (CD) and other systemic granulomatous disorders. It is a condition which may respond to the exclusion of certain food-related chemicals from the diet in up to 60% of patients and, as such, is distinct from gastrointestinal CD. CD is a relapsing systemic inflammatory disease which predominantly affects the gut, and patients suffering from this disease frequently present with abdominal pain, fever and altered bowel habit. A proportion of patients with clinical OFG (without other systemic disease) may have asymptomatic gastrointestinal involvement or go on to develop gut CD suggesting an association between the two diseases. It is estimated that 1% of CD sufferers may have a diagnosis of OFG, but the majority of patients in specialist OFG clinics do not have gut symptoms.