Limitations of fecal calprotectin at diagnosis in untreated pediatric Crohn's disease

RNA Expression of MMP12 Is Strongly Associated with Inflammatory Bowel Disease and Is Regulated by Metabolic Pathways in RAW 264.7 Macrophages

Macrophage metalloelastase or matrix metalloproteinase-12 (MMP12) is a macrophage-specific proteolytic enzyme involved in the physiopathology of many inflammatory diseases, including inflammatory bowel disease. Although previously published data suggested that the modulation of MMP12 in macrophages could be a determinant for the development of intestinal inflammation, scarce information is available on the mechanisms underlying the regulation of MMP12 expression in those phagocytes. Therefore, in this study, we aimed to delineate the association of MMP12 with inflammatory bowel disease and the molecular events leading to the transcriptional control of this metalloproteinase. For that, we used publicly available transcriptional data. Also, we worked with the RAW 264.7 macrophage cell line for functional experiments. Our results showed a strong association of MMP12 expression with the severity of inflammatory bowel disease and the response to relevant biological therapies. In vitro assays revealed that the inhibition of mechanistic target of rapamycin complex 1 (mTORC1) and the stimulation of the AMP-activated protein kinase (AMPK) signaling pathway potentiated the expression of Mmp12. Additionally, AMPK and mTOR required a functional downstream glycolytic pathway to fully engage with Mmp12 expression. Finally, the pharmacological inhibition of MMP12 abolished the expression of the proinflammatory cytokine Interleukin-6 (Il6) in macrophages. Overall, our findings provide a better understanding of the mechanistic regulation of MMP12 in macrophages and its relationship with inflammation.

The search for gastrointestinal inflammation in autism: a systematic review and meta-analysis of non-invasive gastrointestinal markers

BACKGROUND

Gastrointestinal symptoms and inflammatory gastrointestinal diseases exist at higher rates in the autistic population. It is not clear however whether autism is associated with elevated gastrointestinal inflammation as studies examining non-invasive faecal biomarkers report conflicting findings. To understand the research landscape and identify gaps, we performed a systematic review and meta-analysis of studies measuring non-invasive markers of gastrointestinal inflammation in autistic and non-autistic samples. Our examination focused on faecal biomarkers as sampling is non-invasive and these markers are a direct reflection of inflammatory processes in the gastrointestinal tract.

METHODS

We extracted data from case-control studies examining faecal markers of gastrointestinal inflammation. We searched PubMed, Embase, Cochrane CENTRAL, CINAHL, PsycINFO, Web of Science Core Collection and Epistemonikos and forward and backwards citations of included studies published up to April 14, 2023 (PROSPERO CRD42022369279).

RESULTS

There were few studies examining faecal markers of gastrointestinal inflammation in the autistic population, and many established markers have not been studied. Meta-analyses of studies examining calprotectin (n = 9) and lactoferrin (n = 3) were carried out. A total of 508 autistic children and adolescents and 397 non-autistic children and adolescents were included in the meta-analysis of calprotectin studies which found no significant group differences (ROM: 1.30 [0.91, 1.86]). Estimated differences in calprotectin were lower in studies with siblings and studies which did not exclude non-autistic controls with gastrointestinal symptoms. A total of 139 autistic participants and 75 non-autistic controls were included in the meta-analysis of lactoferrin studies which found no significant group differences (ROM: 1.27 [0.79, 2.04]).

LIMITATIONS

All studies included in this systematic review and meta-analysis examined children and adolescents. Many studies included non-autistic controls with gastrointestinal symptoms which limit the validity of their findings. The majority of studies of gastrointestinal inflammation focused on children under 12 with few studies including adolescent participants. Most studies that included participants aged four or under did not account for the impact of age on calprotectin levels. Future studies should screen for relevant confounders, include larger samples and explore gastrointestinal inflammation in autistic adolescents and adults.

CONCLUSIONS

There is no evidence to suggest higher levels of gastrointestinal inflammation as measured by calprotectin and lactoferrin are present in autistic children and adolescents at the population level. Preliminary evidence suggests however that higher calprotectin levels may be present in a subset of autistic participants, who may be clinically characterised by more severe gastrointestinal symptoms and higher levels of autistic traits.

Identification of FCN1 as a novel macrophage infiltration-associated biomarker for diagnosis of pediatric inflammatory bowel diseases

BACKGROUND

The incidence of pediatric inflammatory bowel disease (PIBD) has been steadily increasing globally. Delayed diagnosis of PIBD increases the risk of complications and contributes to growth retardation. To improve long-term outcomes, there is a pressing need to identify novel markers for early diagnosis of PIBD.

METHODS

The candidate biomarkers for PIBD were identified from the GSE117993 dataset by two machine learning algorithms, namely LASSO and mSVM-RFE, and externally validated in the GSE126124 dataset and our PIBD cohort. The role of ficolin-1 (FCN1) in PIBD and its association with macrophage infiltration was investigated using the CIBERSORT method and enrichment analysis of the single-cell dataset GSE121380, and further validated using immunoblotting, qRT-PCR, and immunostaining in colon biopsies from PIBD patients, a juvenile murine DSS-induced colitis model, and THP-1-derived macrophages.

RESULTS

FCN1 showed great diagnostic performance for PIBD in an independent clinical cohort with the AUC of 0.986. FCN1 expression was upregulated in both colorectal biopsies and blood samples from PIBD patients. Functionally, FCN1 was associated with immune-related processes in the colonic mucosa of PIBD patients, and correlated with increased proinflammatory M1 macrophage infiltration. Furthermore, single-cell transcriptome analysis and immunostaining revealed that FCN1 was almost exclusively expressed in macrophages infiltrating the colonic mucosa of PIBD patients, and these FCN1⁺ macrophages were related to hyper-inflammation. Notably, proinflammatory M1 macrophages derived from THP-1 expressed high levels of FCN1 and IL-1β, and FCN1 overexpression in THP-1-derived macrophages strongly promoted LPS-induced activation of the proinflammatory cytokine IL-1β via the NLRP3-caspase-1 axis.

CONCLUSIONS

FCN1 is a novel and promising diagnostic biomarker for PIBD. FCN1⁺ macrophages enriched in the colonic mucosa of PIBD exhibit proinflammatory phenotypes, and FCN1 promotes IL-1β maturation in macrophages via the NLRP3-caspase-1 axis.

Diagnostic Value of Quantitative Contrast-Enhanced Ultrasound in Comparison to Endoscopy in Children With Crohn's Disease

OBJECTIVE

Quantitative contrast-enhanced US (CEUS) provides objective evaluation of bowel wall perfusion and has been reported as a useful method for evaluating Crohn's disease (CD) activity in children. We tested its' diagnostic accuracy in comparison to endoscopy and evaluated its' usefulness in comparison to Pediatric Crohn's Disease Activity Index (PCDAI) and fecal Calprotectin (FC).

MATERIALS AND METHODS

Children with CD and thickened bowel wall on abdominal US were prospectively enrolled. Disease activity was evaluated with quantitative CEUS, PCDAI and FC and compared to a simple endoscopic score for Crohn's disease (SES-CD). Spearman's correlation and Cohen's kappa statistic between the SES-CD and other disease activity measures were performed and diagnostic accuracies calculated.

RESULTS

36 children 3.5-18 years old (mean age 14 years) were included. The quantitative CEUS had 78.57% sensitivity (95%CI 0.59-0.92), 100% specificity (95%CI 0.63-1.0) and 83.33% diagnostic accuracy (95% CI 0.67-0.94). The concordance remission agreement with endoscopy was substantial for quantitative CEUS and PCDAI (quantitative CEUS: κ = 0.62; 95% CI 0.363-0.877; PCDAI: κ = 0.615; 95% CI 0.311-0.920), but only fair for FC (κ = 0.389; 95% CI 0.006-0.783). Correlation between all measures and endoscopy was moderate and statistically significant (quantitative CEUS: r_s  = 0.535, PCDAI: r_s  = 0.543, FC: r_s  = 0.497).

CONCLUSIONS

Quantitative CEUS has a potential of becoming a complementary method for evaluation of CD activity in children due to its' high specificity in comparison to endoscopy. Lower sensitivity makes it deficient as a single measure and further management should be guided by PCDAI and FC results as well.

Evaluation of Fecal Calprotectin, Serum C-Reactive Protein, Erythrocyte Sedimentation Rate, Seromucoid and Procalcitonin in the Diagnostics and Monitoring of Crohn's Disease in Children

Background: The development of diagnostic and monitoring algorithms for Crohn’s disease based on non-invasive methods is of particular importance in children and is the subject of many studies. Objectives: Evaluate the usefulness of fecal calprotectin, serum C-reactive protein, erythrocyte sedimentation rate, seromucoid and procalcitonin in the differential diagnosis of non-inflammatory gastrointestinal tract diseases and Crohn’s disease in children and their usefulness in determining the phenotype of Crohn’s disease. Material and methods: Forty-seven children with non-inflammatory gastrointestinal tract diseases and fifty-four with Crohn’s disease were enrolled. Clinical and endoscopic activity was evaluated based on the Pediatric Crohn’s Disease Activity Index (PCDAI) and the Simple Endoscopic Score for Crohn’s Disease (SES-CD). Results: Fecal calprotectin, C-reactive protein, erythrocyte sedimentation rate and seromucoid were significantly higher in children with Crohn’s disease than in controls (p < 0.001). Fecal calprotectin correlated with clinical and endoscopic activity according to the Pediatric Crohn’s Disease Activity Index (r = 0.338; p = 0.012) and the Simple Endoscopic Score for Crohn’s Disease (r = 0.428; p = 0.001). Non-invasive biomarkers did not correlate with the location and clinical manifestation of Crohn’s disease. Conclusions: Fecal calprotectin, C-reactive protein, erythrocyte sedimentation rate and seromucoid are useful in the differentiation of Crohn’s disease from non-inflammatory gastrointestinal tract diseases in children and in monitoring the clinical course of Crohn’s disease, but not in evaluating activity and phenotype of the disease.

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.

The Use of Fecal Calprotectin Testing in Paediatric Disorders: A Position Paper of the European Society for Paediatric Gastroenterology and Nutrition Gastroenterology Committee

OBJECTIVES

The aim of the study was to review the evidence regarding the clinical use and value of fecal calprotectin (FC) measurements in different gastrointestinal disorders in children.

METHODS

A literature search was conducted in the PubMed, MEDLINE, EMBASE, and Cochrane databases until October 31, 2019. Subtopics were identified and each assigned to individual authors.

RESULTS

A total of 28 recommendations were voted on using the nominal voting technique. Recommendations are given related to sampling, measurement methods, and results interpretation. The 14 authors anonymously voted on each recommendation using a 9-point scale (1 strongly disagree to 9 fully agree). Consensus was considered achieved if at least 75% of the authors voted 6, 7, 8, or 9.

CONCLUSIONS

Consensus was reached for all recommendations. Limitations for the use of FC in clinical practice include variability in extraction methodology, performance of test kits as well as the need to establish local reference ranges because of the influence of individual factors, such as age, diet, microbiota, and drugs. The main utility of FC measurement at present is in the diagnosis and monitoring of inflammatory bowel disease (IBD) as well as to differentiate it from functional gastrointestinal disorders (FAPDs). FC, however, has neither utility in the diagnosis of infantile colic nor to differentiate between functional and organic constipation. A rise in FC concentration, may alert to the risk of developing necrotizing enterocolitis and help identifying gastrointestinal involvement in children with Henoch-Schönlein purpura. FC measurement is of little value in Cow's Milk Protein Allergy, coeliac disease (CD), and cystic fibrosis. FC does neither help to distinguish bacterial from viral acute gastroenteritis (AGE), nor to diagnose Helicobacter Pylori infection, small intestinal bacterial overgrowth (SIBO), acute appendicitis (AA), or intestinal polyps.

Fecal calprotectin in healthy children aged 4-16 years

Reference values of fecal calprotectin (fCP) have not been convincingly established in children. We aimed to investigate fCP concentrations in a larger population of healthy children aged 4–16 years to analyze more in depth the behavior of fCP in this age range and to determine if cut-off levels could be conclusively recommended. A prospective study was conducted to investigate fCP concentrations of healthy children aged 4–16 years. In 212 healthy children, the median and 95th percentile for fCP were 18.8 mg/kg and 104.5 mg/kg, respectively. We found a statistically significant association between the 95th percentile of fCP concentrations and age (p < 0.001). We propose a nomogram to facilitate the interpretation of fCP results in children aged 4–16 years. Further studies are required to validate the proposed values in clinical practice.

Fecal Calprotectin in Combination With Standard Blood Tests in the Diagnosis of Inflammatory Bowel Disease in Children

Introduction: Fecal calprotectin (FC) is a useful non-invasive screening test but elevated levels are not specific to inflammatory bowel disease (IBD). The study aimed to evaluate the sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of FC alone or FC in combination with other standard blood tests in the diagnosis of IBD. Methods: Children aged <17 years who had FC (normal range <50 μg/g) measured and underwent endoscopy over 33 months in Christchurch, New Zealand were identified retrospectively (consecutive sampling). Medical records were reviewed for patient final diagnoses. Results: One hundred and two children were included; mean age was 12.3 years and 53 were male. Fifty-eight (57%) of the 102 children were diagnosed with IBD: 49 with Crohn's disease, eight with ulcerative colitis and one with IBD-unclassified. FC of 50 μg/g threshold provided a sensitivity of 96.6% [95% confident interval (CI) 88.3-99.4%] and PPV of 72.7% (95% CI 61.9-81.4%) in diagnosing IBD. Two children with IBD however were found to have FC <50 μg/g. Sensitivity in diagnosing IBD was further improved to 98.3% (95% CI 90.7-99.1%) when including FC >50 μg/g or elevated platelet count. Furthermore, PPVs in diagnosing IBD improved when FC at various thresholds was combined with either low albumin or high platelet count. Conclusion: Although FC alone is a useful screening test for IBD, a normal FC alone does not exclude IBD. Extending FC to include albumin or platelet count may improve sensitivity, specificity, PPV and NPV in diagnosing IBD. However, prospective studies are required to validate this conclusion.

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.

Response to treatment is more important than disease severity at diagnosis for prediction of early relapse in new-onset paediatric Crohn's disease

BACKGROUND

Paediatric Crohn's disease is characteried by frequently relapsing disease which may lead to hospitalisations and complications.

AIM

To develop predictive models for early relapse following first remission.

METHODS

The GROWTH CD prospective inception cohort was designed to predict risk for early disease relapse and poor outcomes. Newly diagnosed children underwent endoscopies and imaging. They were phenotyped and followed at scheduled visits through 78 weeks for relapses. Twenty-eight dichotomous and continuous variables were assessed at baseline and week 12, including phenotype, inflammatory markers, disease activity (PCDAI) and other markers. Clinical relapses defined as PCDAI >10 after remission were recorded using a relapse form. Logistic regression & risk modelling was performed.

RESULTS

We enrolled 282 eligible patients of whom 178 (63.6%) patients achieved steroid free remission by week 12. Disease complications developed in 22/76(29%) of patients with relapse compared to 20/206 (9.7%) without relapse (P = 0.01). Multivariable analysis demonstrated that while variables from age/gender at diagnosis were not predictive, week 12 variables including PCDAI >5 (P = 0.02), CRP >20 mg/L (P = 0.02), and faecal calprotectin >400 µg/g (P = 0.03) as optimal cut-offs were associated with increased risk of relapse. A prediction model for patients in remission including gender, age, week 12 PCDAI, calprotectin and CRP had sensitivity 43%, specificity 92%, PPV 78%, NPV 71% for relapse.

CONCLUSIONS

Early relapses were associated with a higher risk for disease complications at followup. Relapse prediction based on week 12 disease activity or inflammation is superior to prediction using data from diagnosis.

Proteomic analysis of ascending colon biopsies from a paediatric inflammatory bowel disease inception cohort identifies protein biomarkers that differentiate Crohn's disease from UC

OBJECTIVE

Accurate differentiation between Crohn's disease (CD) and UC is important to ensure early and appropriate therapeutic intervention. We sought to identify proteins that enable differentiation between CD and UC in children with new onset IBD.

DESIGN

Mucosal biopsies were obtained from children undergoing baseline diagnostic endoscopy prior to therapeutic interventions. Using a super-stable isotope labeling with amino acids in cell culture (SILAC)-based approach, the proteomes of 99 paediatric control and biopsies of patients with CD and UC were compared. Multivariate analysis of a subset of these (n=50) was applied to identify novel biomarkers, which were validated in a second subset (n=49).

RESULTS

In the discovery cohort, a panel of five proteins was sufficient to distinguish control from IBD-affected tissue biopsies with an AUC of 1.0 (95% CI 0.99 to 1.0); a second panel of 12 proteins segregated inflamed CD from UC within an AUC of 0.95 (95% CI 0.86 to 1.0). Application of the two panels to the validation cohort resulted in accurate classification of 95.9% (IBD from control) and 80% (CD from UC) of patients. 116 proteins were identified to have correlation with the severity of disease, four of which were components of the two panels, including visfatin and metallothionein-2.

CONCLUSIONS

This study has identified two panels of candidate biomarkers for the diagnosis of IBD and the differentiation of IBD subtypes to guide appropriate therapeutic interventions in paediatric patients.

The prevalence of irritable bowel syndrome-type symptoms in inflammatory bowel disease patients in remission

OBJECTIVE

Symptoms of irritable bowel syndrome (IBS) are common in inflammatory bowel disease (IBD) and are believed to reflect ongoing inflammation. Consequently, a low prevalence of IBS-type symptoms in IBD patients with normal inflammatory markers is expected. We aimed to investigate the prevalence of IBS-type symptoms in IBD patients in biochemical remission (evidenced by low fecal calprotectin levels) and the relationship of these symptoms with fecal calprotectin levels.

PATIENTS AND METHODS

In this observational, cross-sectional study, we included all adults with a history of IBD who had calprotectin levels less than 200 µg/g during routine follow-up between August 2014 and May 2015 at our hospital. Patients were excluded if calprotectin was measured because of gastrointestinal complaints. All patients were approached by telephone to evaluate the presence of IBS-type symptoms using Rome III questionnaires. Patients fulfilling IBS criteria were subclassified according to bowel habits.

RESULTS

In total, 74 patients were included; 33 (45%, 95% confidence interval: 34-56%) fulfilled the IBS criteria. A larger proportion of Crohn's disease patients with IBS-type symptoms had ileal disease compared with Crohn's disease patients without IBS symptoms (55 vs. 24%; P=0.03). Other characteristics were similar between groups. No difference was found in calprotectin levels between patients with and without IBS-type symptoms (P=0.91). The majority of patients with IBS-type symptoms had diarrhea-predominant or mixed-type IBS (64 and 27% of patients with IBS-type symptoms, respectively).

CONCLUSION

The prevalence of IBS-type symptoms in IBD patients in biochemical remission is high. A significant proportion of IBS-type symptoms is unrelated to ongoing inflammation and probably reflects 'true IBS'.

Which PCDAI Version Best Reflects Intestinal Inflammation in Pediatric Crohn Disease?

INTRODUCTION

There is increasing interest in measuring mucosal inflammation in Crohn disease (CD), but there are minimal data correlating the Pediatric Crohn's Disease Activity Index (PCDAI) versions (PCDAI, weighted Pediatric Crohn's Disease Activity Index [wPCDAI], abbreviated Pediatric Crohn's Disease Activity Index [abbrPCDAI], and the short Pediatric Crohn's Disease Activity Index [shPCDAI]) with mucosal inflammation.

METHODS

We aimed to compare the 4 PCDAI versions head to head with endoscopic degree of inflammation as measured by the Simple Endoscopic Score for Crohn's Disease (SES-CD), fecal calprotectin, erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP) and to explore cut-off values that are associated with mucosal healing. We used the prospectively collected data from the ImageKids study on 100 children with CD undergoing colonoscopy and from the Growth Relapse and Outcomes with Therapy study (n = 222), in which 145 children had calprotectin data at week 12 after diagnosis.

RESULTS

All 4 PCDAI versions had fair correlation with the SES-CD (r = 0.42-0.45, all P < 0.001) and CRP (r = 0.32-0.45, all P < 0.01); the wPCDAI and PCDAI were superior to the shorter versions when comparing the blood tests. All versions had poor correlation with calprotectin, and only the wPCDAI reached significance (r = 0.26, P = 0.002 vs r = 0.15, P = 0.07 for PCDAI; r = 0.08, P = 0.37 for shPCDAI; r = 0.06, P = 0.5 for abbrPCDAI). The best cut-off to identify endoscopic mucosal healing was <12.5 points for the wPCDAI (sensitivity 58% and specificity 84%) and <10 for PCDAI (sensitivity 63% and specificity 77%).

CONCLUSIONS

The more feasible wPCDAI and the PCDAI had comparable correlation with measures of endoscopic inflammation. These were slightly superior to the other 2 shorter versions, but still none of the PCDAI versions can give a valid assessment of mucosal healing.

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.

Utility of surrogate markers for the prediction of relapses in inflammatory bowel diseases

Patients with diagnosed inflammatory bowel disease (IBD) will commonly experience a clinical relapse in spite of a prolonged therapy-induced period of clinical remission. The current methods of assessing subclinical levels of low-grade inflammation which predispose patients to relapse are not optimal when considering both cost and patient comfort. Over the past few decades, much investigation has discovered that proteins such as calprotectin that are released from inflammatory cells are capable of indicating disease activity. Along with C-reactive protein and erythrocyte sedimentation rate, calprotectin has now become part of the current methodology for assessing IBD activity. More recently, research has identified that other fecal and serum biomarkers such as lactoferrin, S100A12, GM-CSF autoantibodies, α1-antitrypsin, eosinophil-derived proteins, and cytokine concentrations have variable degrees of utility in monitoring gastrointestinal tract inflammation. In order to provide direction toward novel methods of predicting relapse in IBD, we provide an up-to-date review of these biomarkers and their potential utility in the prediction of clinical relapse, given their observed activities during various stages of clinical remission.

Relationship of clinical symptoms with biomarkers of inflammation in pediatric inflammatory bowel disease

In adult inflammatory bowel disease (IBD) patients, there is a strong discrepancy between symptoms and biomarkers of inflammation. Data on pediatric IBD patients are conflicting. Therefore, we aimed to investigate the relationship between clinical symptoms and biomarkers of inflammation in pediatric IBD. Patients aged <18 years with previously diagnosed Crohn's disease (CD) or ulcerative colitis (UC) were included. Clinical disease activity was determined using the abbreviated Pediatric CD Activity Index (aPCDAI) or Pediatric UC Activity Index (PUCAI). Biochemical disease activity was assessed using fecal calprotectin (FC) and C-reactive protein (CRP). In total, 127 patients (62 male; median age 14.9 years) were included (82 CD, 45 UC). FC correlated weakly with total aPCDAI score (r s = 0.32; 95 % CI 0.12-0.51; p = 0.003) and total PUCAI score (r s = 0.36; 95 % CI 0.07-0.62; p = 0.015). Only aPCDAI components abdominal examination and perirectal disease and PUCAI component activity level had a significant correlation with levels of FC. CRP correlated weakly with total aPCDAI score (r s = 0.28; 95 % CI 0.05-0.46; p = 0.012) and aPCDAI components abdominal examination and activity level. No significant correlation was observed between CRP and total PUCAI score (r s = 0.01; 95 % CI -0.34-0.29; p = 0.961) or individual PUCAI components.

CONCLUSION

There is a strong discrepancy between clinical symptoms and biomarkers of inflammation in children with IBD.

WHAT IS KNOWN

• A substantial proportion of asymptomatic pediatric inflammatory bowel disease (IBD) patients have elevated biomarkers of inflammation. • There is a strong discrepancy between symptoms and biomarkers of inflammation in adults with IBD. What is New: • Clinical symptoms are only weakly associated with levels of fecal calprotectin and serum C-reactive protein in children and adolescents with previously diagnosed IBD. • Similarly to adult IBD patients, there is a strong discrepancy between clinical symptoms and biomarkers of inflammation in children with IBD.

Disease monitoring in inflammatory bowel disease

The optimal method for monitoring quiescent disease in patients with Crohn’s disease (CD) and ulcerative colitis is yet to be determined. Endoscopic evaluation with ileocolonoscopy is the gold standard but is invasive, costly, and time-consuming. There are many commercially available biomarkers that may be used in clinical practice to evaluate disease status in patients with inflammatory bowel disease (IBD), but the most widely adopted biomarkers are C-reactive protein (CRP) and fecal calprotectin (FC). This review summarizes the evidence for utilizing CRP and FC for monitoring IBD during clinical remission and after surgical resection. Endoscopic correlation with CRP and FC is evaluated in each disease state. Advantages and drawbacks of each biomarker are discussed with special consideration of isolated ileal CD. Fecal immunochemical testing, traditionally used for colorectal cancer screening, is mentioned as a potential new alternative assay in the evaluation of IBD. Based on a mixture of information gleaned from biomarkers, clinical status, and endoscopic evaluation, the best treatment decisions can be made for the patient with IBD.

Predicting Endoscopic Crohn's Disease Activity Before and After Induction Therapy in Children: A Comprehensive Assessment of PCDAI, CRP, and Fecal Calprotectin

BACKGROUND

Mucosal healing (MH) is a vital early endpoint in management of Crohn's disease (CD). MH depends on endoscopic assessment and there is increasing interest in non-invasive proxies, Pediatric Crohn's Disease activity Index (PDCAI), C-reactive protein (CRP) and fecal calprotectin (FC). These proxies must be validated against endoscopic disease activity (SES-CD) at diagnosis and after induction therapy in well characterized cohorts of children with CD.

METHODS

A prospective cohort of 24 newly diagnosed children (<16 yr) with luminal CD quantifiable on complete ileo-colonoscopy had paired PCDAI, CRP, FC and SES-CD at diagnosis and after 8 weeks therapy with exclusive enteral nutrition or steroids.

RESULTS

At diagnosis: PCDAI had poor correlation (r = 0.33); CRP (r = 0.54) and FC (r = 0.46) had moderate correlation with SES-CD. After induction therapy: 11/24 had inactive disease (SES-CD 0-2); PCDAI (r = 0.34) and CRP (0.28) had poor correlation with SES-CD, many children with SES-CD ≥3 having normalization of both PCDAI and CRP. FC had good correlation (r = 0.50) but many with SES-CD 0-2 had FC >200 μg/gm stool. FC<500 (positive likelihood ratio, 3.2) and FC drop >50% (positive likelihood ratio, 3.8) had greater predictive value for inactive disease. Composite PCDAI (<10), CRP (<5 mg/dl) & FC <500 μg had excellent Negative LR (0.2) predicting inactive disease.

CONCLUSIONS

PCDAI is unreliable for endoscopic disease severity assessment. Only FC correlates with endoscopic activity after therapy but cut off <200 μg is too high for defining endoscopic recovery in children. Composite normalized PCDAI, CRP and FC <500 μg should be considered the non-invasive endpoint for treatment response in pediatric CD.

Fecal calprotectin in diagnosis and clinical assessment of inflammatory bowel disease

The fecal neutrophil-derived biomarker calprotectin has several features of an ideal noninvasive test for detecting intestinal inflammation: it is simple, reliable, and low in cost. Its utility in differentiating inflammatory bowel diseases (IBDs) from functional conditions such as irritable bowel syndrome is well documented. Fecal calprotectin (FC) correlates closely with endoscopic activity of IBD. Emerging evidence suggest its usefulness in serial monitoring of disease activity and of therapy success in IBD. A low FC concentration predicts persistence of clinical remission especially in non-symptomatic ulcerative colitis and Crohn's colitis. Here, an overview is given to the current role of FC in diagnosis and clinical assessment of IBD.

The role and utility of faecal markers in inflammatory bowel disease

Crohn's disease and ulcerative colitis are characterized by periods of symptomatic relapse and remission. Diagnosis and assessment of inflammatory bowel disease has so far been based on clinical evaluation, serum parameters, radiology and endoscopy. Faecal markers such as calprotectin or lactoferrin have emerged as new diagnostic tools to detect and monitor intestinal inflammation. This review focuses on their potential clinical applications and limitations in the management of inflammatory bowel disease.

ESPGHAN revised porto criteria for the diagnosis of inflammatory bowel disease in children and adolescents

BACKGROUND

The diagnosis of pediatric-onset inflammatory bowel disease (PIBD) can be challenging in choosing the most informative diagnostic tests and correctly classifying PIBD into its different subtypes. Recent advances in our understanding of the natural history and phenotype of PIBD, increasing availability of serological and fecal biomarkers, and the emergence of novel endoscopic and imaging technologies taken together have made the previous Porto criteria for the diagnosis of PIBD obsolete.

METHODS

We aimed to revise the original Porto criteria using an evidence-based approach and consensus process to yield specific practice recommendations for the diagnosis of PIBD. These revised criteria are based on the Paris classification of PIBD and the original Porto criteria while incorporating novel data, such as for serum and fecal biomarkers. A consensus of at least 80% of participants was achieved for all recommendations and the summary algorithm.

RESULTS

The revised criteria depart from existing criteria by defining 2 categories of ulcerative colitis (UC, typical and atypical); atypical phenotypes of UC should be treated as UC. A novel approach based on multiple criteria for diagnosing IBD-unclassified (IBD-U) is proposed. Specifically, these revised criteria recommend upper gastrointestinal endoscopy and ileocolonscopy for all suspected patients with PIBD, with small bowel imaging (unless typical UC after endoscopy and histology) by magnetic resonance enterography or wireless capsule endoscopy.

CONCLUSIONS

These revised Porto criteria for the diagnosis of PIBD have been developed to meet present challenges and developments in PIBD and provide up-to-date guidelines for the definition and diagnosis of the IBD spectrum.

Biomarkers of inflammatory bowel disease

Inflammatory bowel disease (IBD) is a chronic disease mostly involved with intestine with unknown etiology. Diagnosis, evaluation of severity, and prognosis are still present as challenges for physicians. An ideal biomarker with the characters such as simple, easy to perform, noninvasive or microinvasive, cheap, rapid, and reproducible is helpful for patients and clinicians. Currently biomarkers applied in clinic include CRP, ESR, pANCA, ASCA, and fecal calprotectin. However, they are far from ideal. Lots of studies are focused on seeking for ideal biomarker for IBD. Herein, the paper reviewed recent researches on biomarkers of IBD to get advances of biomarkers in inflammatory bowel disease.

The diagnostic accuracy of fecal calprotectin during the investigation of suspected pediatric inflammatory bowel disease: a systematic review and meta-analysis

OBJECTIVES

Fecal calprotectin (FC) is increasingly used during the diagnosis of inflammatory bowel disease (IBD), outperforming blood markers during investigation in children. Tests that reduce endoscopy rates in children with suspected gut inflammation would be beneficial. We aimed to determine the usefulness of FC in children undergoing their primary investigation for suspected IBD by systematic review and meta-analysis.

METHODS

An electronic search was performed with keywords relating to IBD and calprotectin in multiple electronic resources from 1946 to May 2012; a hand search was also performed. Inclusion criteria were studies that reported FC levels before the endoscopic investigation of IBD in patients less than 18 years old. Studies were evaluated using the Quality Assessment of Diagnostic Accuracy Studies tool, and a meta-analysis was performed using a hierarchical summary receiver operating curve model.

RESULTS

Eight papers met the inclusion criteria (six prospective and two retrospective case-control studies); methodological quality was determined in detail for each study. The 8 studies presented FC levels at presentation in 715 patients, 394 pediatric IBD patients, and 321 non-IBD controls. Pooled sensitivity and specificity for the diagnostic utility of FC during the investigation of suspected pediatric IBD were 0.978 (95% confidence interval (CI), 0.947-0.996) and 0.682 (95% CI, 0.502-0.863), respectively; the positive and negative likelihood ratios were 3.07 and 0.03, respectively.

CONCLUSIONS

FC has a high sensitivity and a modest specificity during the diagnosis of suspected pediatric IBD. Further work is required to determine the effect of FC levels on endoscopy rates and its role during the re-evaluation of those with confirmed disease.

The long-term outcome of anti-tumor necrosis factor-α therapy related to fecal calprotectin values during induction therapy in pediatric inflammatory bowel disease

OBJECTIVE

Monitoring fecal calprotectin (FC) could assist in the assessment of the therapeutic response of inflammatory bowel disease (IBD). There are few studies on long-term prognosis related to the FC value response to infliximab induction therapy, thus providing the aim of this study on pediatric patients.

METHODS

FC levels were measured during the induction and maintenance phase of infliximab therapy (5 mg/kg) in 76 pediatric IBD patients introduced to maintenance therapy. The long-term outcomes and clinical disease activity were retrospectively related to the FC response to induction.

RESULTS

The median pretreatment FC level of 817 μg/g stool (range <5-24,000) declined to 372 μg/g (range 5-2430) by week 6, with a low level (<100 μg/g) in 35% (pooled comparable data for ulcerative colitis and Crohn's). Clinical activity indices showed remission in 59% (pediatric Crohn's disease activity index: <10, n = 33; pediatric ulcerative colitis activity index: <10 n = 12). In 49 patients (64%), infliximab therapy was discontinued (inadequate effect/surgery = 27; remission/bridging to azathioprine = 12; adverse effect = 6; antibodies to infliximab n = 4) during the study period with a median follow up of 1.1 years (interquartile range [IQR]: 0.71-4.4). Those who discontinued the therapy within the first year due to an inadequate effect had higher median FC level during induction than the other patients (median 633 µg/g, IQR: 197-819 and median 219 µg/g, IQR: 71-508, respectively; p < 0.025) and were less frequently in clinical remission at week 6 (p < 0.01).

CONCLUSIONS

The long-term prognosis of infliximab therapy is related to the response to induction therapy in pediatric IBD and reflected in low FC values between weeks 2 and 6 and clinical remission.

Fecal calprotectin, MMP-9, and human beta-defensin-2 levels in pediatric inflammatory bowel disease

PURPOSE

Fecal MMP-9 and human beta-defensin-2 (HBD-2)levels, potential markers of intestinal inflammation, are in sufficiently explored in pediatric inflammatory bowel disease(IBD). The aim was to study fecal MMP-9 and HBD-2 in pediatric IBD to compare their performance to calprotectin and to study whether they would provide additional value in categorizing patients according to their disease subtype.

METHODS

Fecal calprotectin, MMP-9, and HBD-2 levels were measured with ELISA in 110 pediatric patients with IBD(Crohn’s disease, n = 68; ulcerative colitis (UC), n = 27; unclassified, n = 15; median age, 14). To compare the performance of the fecal markers, the area under the receiver operating characteristics curve (±95 % CI) was used. In addition,the best cut-off values of each measure to differentiate IBD patients and controls (n = 27 presenting with diarrhea, abdominal pain, and/or anemia) were derived by maximizing sensitivity and specificity.

RESULTS

Of the fecal markers studied, calprotectin performed best for separation of IBD and non-IBD patients with the are a under curve (AUC) of 0.944 (95 % CI, 0.907 to 0.981). For MMP-9, AUC was 0.837 (95% CI, 0.766 to 0.909), the levels being significantly higher in active IBD and in UC compared with Crohn’s disease (p = 0.0013), but categorization of these patient groups did not take place. HBD-2 did not categorize any of the studied groups.

CONCLUSIONS

Calprotectin was the best fecal marker in pediatric IBD, but MMP-9 showed almost comparable performance in UC, suggesting applicability as a surrogate marker of inflammation. Fecal HBD-2 did not bring information to the disease characteristics of pediatric IBD patients.

A new rapid test for fecal calprotectin predicts endoscopic remission and postoperative recurrence in Crohn's disease

INTRODUCTION

Fecal calprotectin (FC), as determined by the enzyme-linked immunoassay (ELISA) test, has been proposed as a promising biomarker of endoscopic activity in Crohn's disease (CD). However data on its accuracy in predicting endoscopic remission according to location and postoperative recurrence (POR) is scarce. Our objective was to evaluate the ability of FC determined by a new quantitative point-of-care test (FC-QPOCT) to predict endoscopic remission and POR in CD patients.

METHODS

FC was determined simultaneously by an enzyme-linked immunoassay test (FC-ELISA) and a FC-QPOCT in CD patients undergoing colonoscopy. Clinical disease activity was assessed according to the Crohn's Disease Activity Index (CDAI). Endoscopic results were assessed according to the Crohn's Disease Endoscopic Activity Index of Severity (CDEIS) and postoperative recurrence according to the Rutgeerts' score.

RESULTS

A total of 115 ileocolonoscopies were performed (29 on patients with ileocolonic resection). FC levels correlated more closely with the CDEIS than leucocytes, platelets or CRP. The prediction of "endoscopic remission" (CDEIS<3), using FC-QPOCT (cut-off 272 μg/g) and FC-ELISA (cut-off 274 μg/g) presented an AUC of 0.933 and 0.935 respectively. FC-QPOCT results correlated better with endoscopic activity in the ileocolonic location (Pearson's correlation, r=0.879; P<0.001), than the colonic (r=0.725; P<0.001) or the ileal location (r=0.437; P=0.016). Median FC-QPOCT levels discriminated Rutgeerts' score i0-i1 from i2-i4 (98 (range 30-306) μg/g vs. 234.5 (range 100-612) μg/g respectively, P=0.012).

CONCLUSIONS

FC determined by rapid quantitative test predicts "endoscopic remission" and endoscopic postoperative recurrence in CD patients.

Fecal calprotectin and clinical disease activity in pediatric ulcerative colitis

Objective. To explore fecal calprotectin levels in pediatric ulcerative colitis (UC) in relation with the validated clinical activity index PUCAI. Methods. This study included all 37 children (median age 14 years) with UC who had calprotectin measured (PhiCal ELISA Test) by the time of PUCAI assessment at the Children's Hospital of Helsinki in a total of 62 visits. Calprotectin values <100 μg/g of stool were considered as normal. The best cut-off value of each measure to predict 3-month clinical outcome was derived by maximizing sensitivity and specificity. Results. In clinically active disease (PUCAI ≥ 10), calprotectin was elevated in 29/32 patients (91% sensitivity). When in clinical remission, 26% (8/30) of the children had normal calprotectin but 7 (23%) had an exceedingly high level (>1000 μg/g). The best cut-off value for calprotectin for predicting poor outcome was 800 μg/g (sensitivity 73%, specificity 72%; area under the ROC curve being 0.71 (95%CI 0.57–0.85)) and for the PUCAI best cut-off values >10 (sensitivity 62%, specificity 64%; area under the ROC curve 0.714 (95%CI 0.58–0.85)). Conclusion. The clinical relevance of somewhat elevated calprotectin during clinical remission in pediatric UC is not known and, until further evidence accumulates, does not indicate therapy escalation.

Clinical utility of calprotectin and lactoferrin in patients with inflammatory bowel disease: is there something new from the literature?

The identification of noninvasive biomarkers is still one of the major issue for gastroenterologists dealing with inflammatory bowel disease patients, due to the chronicity of these conditions and the early onset of symptoms in the majority of cases. Research attention has focused mainly on fecal proteins, especially calprotectin and lactoferrin, and most of the published data are reassuring about their applicability in the diagnosis and monitoring of these patients. However, there are still pending questions regarding the reliability of fecal proteins especially in the era of mucosal healing and biologics.

Effect of bowel cleansing for colonoscopy on fecal calprotectin levels in pediatric patients

The recent development of easily applicable fecal surrogate markers of intestinal inflammation, such as fecal calprotectin (FC), has provided a new means for objectively assessing disease activity in patients with chronic inflammatory bowel disease. Because the use of these markers is about to emerge, it is important to be aware of the possible limitations of measurements. We assessed levels of FC during bowel cleansing. In patients with high FC levels at baseline, the values measured during bowel cleansing varied considerably, remaining high or even returning to normal. Thus, stool sampling for FC assessment is not recommended during bowel preparation for colonoscopy.