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

Unravelling metabolite-microbiome interactions in inflammatory bowel disease through AI and interaction-based modelling

Inflammatory Bowel Diseases (IBDs) are chronic inflammatory disorders of the gastrointestinal tract and colon affecting approximately 7 million individuals worldwide. The knowledge of specific pathology and aetiological mechanisms leading to IBD is limited, however a reduced immune system, antibiotic use and reserved diet may initiate symptoms. Dysbiosis of the gut microbiome, and consequently a varied composition of the metabolome, has been extensively linked to these risk factors and IBD. Metagenomic sequencing and liquid-chromatography mass spectrometry (LC-MS) of N = 220 fecal samples by Fransoza et al., provided abundance data on microbial genera and metabolites for use in this study. Identification of differentially abundant microbes and metabolites was performed using a Wilcoxon test, followed by feature selection of random forest (RF), gradient-boosting (XGBoost) and least absolute shrinkage operator (LASSO) models. The performance of these features was then validated using RF models on the Human Microbiome Project 2 (HMP2) dataset and a microbial community (MICOM) model was utilised to predict and interpret the interactions between key microbes and metabolites. The Flavronifractor genus and microbes of the families Lachnospiraceae and Oscillospiraceae were found differential by all models. Metabolic pathways commonly influenced by such microbes in IBD were CoA biosynthesis, bile acid metabolism and amino acid production and degradation. This study highlights distinct interactive microbiome and metabolome profiles within IBD and the highly potential pathways causing disease pathology. It therefore paves way for future investigation into new therapeutic targets and non-invasive diagnostic tools for IBD.

Utility of the Endoscopic Healing Index in Identifying Active Inflammation in Patients with Crohn's Disease: Real World Data from a Tertiary Center

BACKGROUND

The Endoscopic Healing Index (EHI) analyzes biomarkers in a patient's peripheral blood to assess mucosal healing. We aimed to characterize the effectiveness of the EHI as a predictor of disease activity in a real world clinical setting.

METHODS

This retrospective study looked at patients treated and followed up at the University of Chicago Medicine IBD center who had EHI tests done as part of routine clinical care. The results of the EHI were compared with radiological imaging or endoscopy performed within 3 months of the EHI in order to determine accuracy at diagnosing active inflammation.

RESULTS

Fifty-five patients with CD and with an available EHI were included in this study. Four (50%) patients with an EHI of < 20 (n = 8) had evidence of objective inflammation. A cutoff of ≤ 20 had a sensitivity of 89% and specificity of 23.5% for predicting no evidence of any objective inflammation with an AUROC of 0.69. This score had a negative predictive value (NPV) of 50% and positive predictive value (PPV) of 72.3%. A cutoff EHI of 30 tended to classify patients as either having objective evidence of inflammation or not more often than FCAL (Correctly classifying inflammation: 89% vs 64%, respectively; p = 0.32).

CONCLUSION

In this real world analysis, the EHI showed poor predictive value for the absence of active inflammation as assessed by imaging or endoscopy, has limited utility in confirming deep remission and should be used with another objective modality.

Application of clinical decision support tools for predicting outcomes with vedolizumab therapy in patients with inflammatory bowel disease: A KASID multicentre study

BACKGROUND/AIM

We aimed to validate clinical decision support tools (CDSTs) to predict real-life effectiveness of vedolizumab (VDZ) in patients with inflammatory bowel disease.

METHODS

We retrospectively enrolled patients with Crohn's disease (CD) or ulcerative colitis (UC) treated with VDZ at 10 tertiary referral centres in Korea between January 2017 and November 2021. We assessed clinical remission (CREM) and response (CRES), corticosteroid-free clinical remission (CSF-CREM) and response (CSF-CRES), biochemical response based on C-reactive protein (BioRES[CRP]) and faecal calprotectin (BioRES[FC]), endoscopic healing (EH), and the need to optimise or switch drugs based on CDST-defined response groups. Additionally, the area under the receiver operating characteristics curve (AUC) for the CDSTs was calculated.

RESULTS

We included 143 patients with CD and 219 with UC. We observed incremental trends on CSF-CRES at week 14 (W14) (ptrend = 0.004) and decreasing trends for the need to optimise or switch drugs (ptrend = 0.016) in CD from the low to high probability groups. Except for CSF-CREM at W54, we noticed incremental trends for all clinical responses at W14, W26 and W54 (ptrend <0.001) in UC. W26 and W54 BioRES[CRP] and W14 EH also showed increasing trends (ptrend <0.05) in UC. With increasing probabilities of response, drug optimisation or switching was less frequently required in UC (ptrend = 0.013). With 26 points cut-off, CDSTs effectively identified W14 CSF-CRES, W26 BioRES[CRP], BioRES[FC] and W54 BioRES[CRP] in UC, all with AUCs >0.600, whereas CDSTs showed poor accuracy in CD.

CONCLUSIONS

CDSTs for VDZ had acceptable accuracy in predicting effectiveness outcomes including clinical and biochemical outcomes in UC. However, their utility in CD was limited.

Fecal Calprotectin in Patients with Crohn's Disease: A Study Based on the History of Bowel Resection and Location of Disease

Fecal calprotectin (FC) is commonly used to assess Crohn's disease (CD) activity. However, standardized cut-off values accounting for bowel resection history and disease location are lacking. In this study, we analyzed data from patients with CD who underwent magnetic resonance enterography, ileocolonoscopy, and FC measurements from January 2017 to December 2018. In 267 cases from 254 patients, the FC levels in the 'operated' patients were higher when the disease was active compared with those who were in the remission group (178 vs. 54.7 μg/g; p < 0.001), and similar findings were obtained for the 'non-operated' patients (449.5 vs. 40.95 μg/g; p < 0.001). The FC levels differed significantly according to the location of inflammation, with lower levels in the small bowel compared to those in the colon. The FC cut-off levels of 70.8 μg/g and 142.0 μg/g were considered optimal for predicting active disease for operated and non-operated patients, respectively. The corresponding FC cut-off levels of 70.8 μg/g and 65.0 μg/g were observed for patients with disease only in the small bowel. In conclusion, different FC cut-off values would be applicable to patients with CD based on their bowel resection history and disease location. Tight control with a lower FC target may benefit those with a history of bowel resection or small-bowel-only disease.

Circulatory resistin levels in inflammatory bowel disease: a systematic review and meta-analysis

BACKGROUND

Inflammatory bowel disease (IBD), including ulcerative colitis (UC) and Crohn's disease (CD), is a chronic relapsing-remitting systemic disease of the gastrointestinal tract with rising incidence. Studies have shown that adipocytes play a crucial role in patients with IBD by actively participating in systemic immune responses. The present study was designed to investigate the correlation between the circulatory levels of resistin, as an adipokine, and active and remission phases of IBD in comparison with healthy controls.

METHODS

Relevant articles were retrieved from PubMed, Embase, the Web of Science, and Scopus from inception until June 2023. Estimation of the standardized mean difference (SMD) and 95% confidence interval (CI) for comparison of plasma/serum resistin levels between IBD patients, patients in remission, and healthy controls were conducted through random-effect meta-analysis.

RESULTS

A total of 19 studies were included, assessing 1836 cases. Meta-analysis indicated that generally, serum/plasma resistin levels were higher in IBD patients in comparison with healthy controls (SMD 1.33, 95% CI 0.58 to 2.08, p-value < 0.01). This was true for each of the UC and CD separate analyses, as well. Moreover, it was shown that higher serum/plasma resistin levels were detected in the active phase of IBD than in the remission phase (SMD 1.04, 95% CI 0.65 to 1.42, p-value = 0.01). Finally, higher serum/plasma resistin levels were found in the remission phase compared to healthy controls (SMD 0.60, 95% CI 0.15 to 1.06, p-value < 0.01).

CONCLUSION

The results of this systematic review and meta-analysis support the conclusion that circulating resistin levels are increased in IBD (both UC and CD). Also, higher resistin levels were recorded in the remission phase of IBD in comparison with healthy controls. This indicates that further studies may provide valuable insights into the role of resistin in the pathogenesis of IBD.

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.

Combination of leucine-rich alpha-2 glycoprotein and fecal markers detect Crohn's disease activity confirmed by balloon-assisted enteroscopy

BACKGROUND/AIMS

Endoscopic activity confirmed by enteroscopy is associated with poor clinical outcome in Crohn's disease (CD). We investigated which of the existing biomarkers best reflects endoscopic activity in CD patients including the small bowel, and whether their combined use can improve accuracy.

METHODS

One hundred and four consecutive patients with ileal and ileocolonic type CD who underwent balloon-assisted enteroscopy (BAE) from October 2021 to August 2022 were enrolled, with clinical and laboratory data prospectively collected and analyzed.

RESULTS

Hemoglobin, platelet count, C-reactive protein, leucine-rich alpha-2 glycoprotein (LRG), fecal calprotectin, and fecal hemoglobin all showed significant difference in those with ulcers found on BAE. LRG and fecal calprotectin showed the highest areas under the curve (0.841 and 0.853) for detecting ulcers. LRG showed a sensitivity of 78% and specificity of 80% at a cutoff value of 13 μg/mL, whereas fecal calprotectin showed a sensitivity of 91% and specificity of 67% at a cutoff value of 151 μg/g. Dual positivity for LRG and fecal calprotectin, as well as LRG and fecal hemoglobin, both predicted ulcers with an improved specificity of 92% and 100%. A positive LRG or fecal calprotectin/hemoglobin showed an improved sensitivity of 96% and 91%. Positivity for LRG and either of the fecal biomarkers was associated with increased risk of hospitalization, surgery, and relapse.

CONCLUSIONS

The biomarkers LRG, fecal calprotectin, and fecal hemoglobin can serve as noninvasive and accurate tools for assessing activity in CD patients confirmed by BAE, especially when used in combination.

Serum food specific IgG antibodies are associated with small bowel inflammation in patients with Crohn's disease

BACKGROUND/AIMS

Food antigens are thought to play a vital role in the initiation and perpetuation of Crohn's disease (CD). The main purpose of this study was to evaluate the potential association of serum food specific IgG antibodies and small bowel (SB) inflammation in CD patients.

METHODS

We conducted a prospective observational study with 96 CD patients. Demographic, disease-related data and inflammatory parameters were collected. Serum food IgG antibodies were measured using enzyme-linked immunosorbent assay (ELISA). Capsule endoscopy was performed to detect SB inflammation quantified by the Lewis Score.

RESULTS

Seventy-eight of (81.3%) CD patients were detected positive for at least one food-specific antibody. The five most prevalent food antibodies in CD patients were tomato, egg, corn, rice, and soybean. Patients with SB inflammation had a higher positive rate of food IgG antibodies (P = 0.010) and more IgG-positive food items (P = 0.010) than those without. Specifically, patients with SB inflammation were more likely to have positive food-specific IgG against egg (P = 0.014), corn (P = 0.014), and wheat (P = 0.048). Additionally, the number of positive food IgGs ≥ 3 and elevated ESR were independently associated with concurrent SB inflammation (P = 0.015 and P = 0.013, respectively).

CONCLUSION

Our study confirmed that CD patients with SB inflammation had a higher positive rate of food IgG antibodies and more IgG-positive food items. The number of food positive IgGs ≥ 3 and elevated ESR were independently associated with concurrent SB inflammation.

Amplification of an Electrochemiluminescence-Emissive Aptamer into DNA Nanotags for Sensitive Fecal Calprotectin Determination

The precision additive manufacturing and tessellated multitasking out of the structural DNA nanotechnology enable a configurable expression of densified electrochemiluminescent (ECL) complexes, which would streamline the bioconjugation while multiplying signals. Herein, a completely DNA-scaffold ECL "polyploid" was replicated out via the living course of rolling circle amplification. The amplicon carried the aptameric sequences of ZnPPIX/TSPP porphyrin as photoreactive centers that rallied at periodical intervals of the persistent extension into a close-packed nanoflower, ZnPDFI/II. Both microscopies and electrophoresis proved the robust nesting of guests at their deployed gene loci, while multispectral comparisons among cofactor substituents pinpointed the pivotal roles of singlet seclusion and Zn2+-chelation for the sake of intensive ECL irradiation. The adversity-resilient hydrogel texture made lipoidal filmogens as porphyrinic ECL prerequisites to be of no need at all, thus not only simplifying assay flows but also inspiring an in situ labeling plan. Upon bioprocessing optimization, an enriched probe ZnPDFIII was further derived that interpolated the binding motif related to calprotectin as validated by molecular docking and affinity titration. With it being a strongly indicative marker of inflammatory bowel disease (IBD), a competitive ECL aptasensing strategy was contrived, managing a signal-on and sensitive detection in mild conditions with a subnanogram-per-milliliter limit of detection by 2 orders of magnitude lower than the standard method as well as a comparable accuracy in clinical stool sample testing. Distinct from those conventional chemophysical rebuilding routes, this de novo biosynthetic fusion demonstrated a promising alternative toward ECL-source bioengineering, which may intrigue vibrant explorations of other ECL-shedding fabrics and, accordingly, a new bioanalytic mode downstream.

AGA Clinical Practice Guideline on the Role of Biomarkers for the Management of Crohn's Disease

BACKGROUND & AIMS

Biomarkers are used frequently for evaluation and monitoring of patients with Crohn's disease (CD). This American Gastroenterological Association (AGA) guideline is intended to support practitioners in decisions about the use of biomarkers for the management of CD.

METHODS

A multidisciplinary panel of content experts and guideline methodologists used the Grading of Recommendations Assessment, Development and Evaluation framework to formulate patient-centered clinical questions and review evidence on the performance of fecal calprotectin, serum C-reactive protein (CRP), and Endoscopic Healing Index in patients with established CD who were asymptomatic, had symptoms of varying severity, or were in surgically induced remission. Biomarker performance was assessed against the gold standard of endoscopic activity, defined as a Simple Endoscopic Score for Crohn's Disease ≥3. The panel used the Grading of Recommendations Assessment, Development and Evaluation Evidence-to-Decision framework to develop recommendations for use of biomarkers in various settings. Implementation considerations were formulated for each recommendation to inform clinical practice.

RESULTS

The guideline panel made 11 conditional recommendations. In patients with CD in symptomatic remission, the panel suggests use of a biomarker- and symptom-based monitoring strategy over symptoms alone. In patients in symptomatic remission, a fecal calprotectin <150 μg/g and normal CRP rules out active inflammation, avoiding endoscopic evaluation for assessment of disease activity. However, elevated biomarkers in this setting merit confirmation with endoscopy before treatment adjustment. In patients with CD with mild symptoms, neither normal nor elevated biomarkers alone are sufficiently accurate to determine endoscopic activity. In patients with CD with moderate to severe symptoms, elevated fecal calprotectin or serum CRP suggests endoscopic activity, precluding routine endoscopic assessment for disease activity. In patients with CD in surgically induced remission in low-risk patients on pharmacologic prophylaxis, a normal fecal calprotectin reliably rules out endoscopic recurrence. In other postoperative settings, the panel suggests endoscopic assessment for establishing postoperative recurrence.

CONCLUSIONS

In patients with CD, fecal calprotectin and serum CRP can inform disease management in both asymptomatic and symptomatic disease. Discordance between symptom assessment and biomarker value may merit endoscopic evaluation for confirmation of status of disease activity.

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.

Fecal immunochemical test for hemoglobin versus fecal calprotectin to monitor endoscopic activity in inflammatory bowel disease

AIM

endoscopy identifies inflammatory activity, however, it is an unpleasant test and is not always accessible. The aim of the study was to compare the usefulness of quantitative fecal immunochemical test (FIT) versus fecal calprotectin (FC) to determine endoscopic activity in patients with inflammatory bowel disease (IBD).

METHODS

cross-sectional prospective observational study. The stool samples were collected within three days before starting the preparation for the colonoscopy. We used the Mayo index for ulcerative colitis (UC) and the simplified endoscopic index for Crohn's disease (CD). Mucosal healing (MH) was defined as the score 0 points in each of the endoscopic indices.

RESULTS

eighty-four patients were included, 40 (47.6 %) with UC. In patients with IBD, FIT and FC showed a significant correlation with the presence of inflammatory activity/MH on endoscopy, with no statistically significant differences between the two receiver-operating characteristic (ROC) curves. Both tests improved their diagnostic performance when assessing patients with UC; the Spearman correlations between FIT and FC and endoscopic inflammatory activity were r = 0.6 (p = 0.0001) and r = 0.7 (p = 0.0001), respectively. In Crohn's disease, the diagnostic utility of both tests was lower.

CONCLUSIONS

FIT is an alternative to monitor endoscopic activity among ulcerative colitis patients. In Crohn's disease, more studies are needed to determine the role of fecal biomarkers.

Resistin, Elastase, and Lactoferrin as Potential Plasma Biomarkers of Pediatric Inflammatory Bowel Disease Based on Comprehensive Proteomic Screens

Inflammatory bowel disease (IBD) is an immune-mediated chronic inflammation of the intestine, which can present in the form of ulcerative colitis (UC) or as Crohn's disease (CD). Biomarkers are needed for reliable diagnosis and disease monitoring in IBD, especially in pediatric patients. Plasma samples from a pediatric IBD cohort were interrogated using an aptamer-based screen of 1322 proteins. The elevated biomarkers identified using the aptamer screen were further validated by ELISA using an independent cohort of 76 pediatric plasma samples, drawn from 30 CD, 30 UC, and 16 healthy controls. Of the 1322 proteins screened in plasma from IBD patients, 129 proteins were significantly elevated when compared with healthy controls. Of these 15 proteins had a fold change greater than 2 and 28 proteins had a fold change >1.5. Neutrophil and extracellular vesicle signatures were detected among the elevated plasma biomarkers. When seven of these proteins were validated by ELISA, resistin was the only protein that was significantly higher in both UC and CD (p < 0.01), with receiver operating characteristic area under the curve value of 0.82 and 0.77, respectively, and the only protein that exhibited high sensitivity and specificity for both CD and UC. The next most discriminatory plasma proteins were elastase and lactoferrin, particularly for UC, with receiver operating characteristic area under the curve values of 0.74 and 0.69, respectively. We have identified circulating resistin, elastase, and lactoferrin as potential plasma biomarkers of IBD in pediatric patients using two independent diagnostic platforms and two independent patient cohorts.

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.

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.

Fecal calprotectin predicts endoscopic activity and mucosal healing of small bowel Crohn's disease evaluated by double-balloon endoscopy

PURPOSE

Fecal calprotectin (FC) levels can reflect the level of intestinal inflammation. Crohn's disease (CD), which affects the small bowel, has not been linked to FC levels. We determined if FC levels and endoscopic activity were related by performing double-balloon endoscopy (DBE).

METHODS

Herein, patients with small bowel CD diagnosed by DBE between January 2020 and January 2022 were prospectively observed. Feces and blood samples of patients were collected before performing DBE and checked for the levels of FC and serological biomarkers. The endoscopic activity and mucosal healing (MH) were evaluated using the partial simple endoscopic score (pSES-CD).

RESULTS

In all 254 CD patients, FC levels were correlated with pSES-CD (r = 0.775, P < 0.001). Even in patients with isolated small bowel CD, FC levels were strongly correlated with pSES-CD (r = 0.753, P < 0.001). In all patients, FC as an endoscopic remission indicator was found to have an area under the curve (AUC) of 0.872, with a cut-off value of 156.09 µg/g. In patients with isolated small bowel CD, FC yielded a high AUC of 0.865 for predicting endoscopic remission, with a cut-off value of 211.48 µg/g, sensitivity of 73.95%, and specificity of 91.30%. FC was optimally cut-off at 76.99 µg/g to predict MH in accordance with the AUC of 0.877.

CONCLUSIONS

Using DBE findings, FC was found to be significantly correlated with pSES-CD. Even in isolated small bowel CD, FC may be a more reliable marker of accurately predicting endoscopic remission and MH.

Intestinal fatty acid binding protein is a disease biomarker in paediatric coeliac disease and Crohn's disease

Background

There is a clinical need to develop biomarkers of small bowel damage in coeliac disease and Crohn’s disease. This study evaluated intestinal fatty acid binding protein (iFABP), a potential biomarker of small bowel damage, in children with coeliac disease and Crohn’s disease.

Methods

The concentration iFABP was measured in plasma and urine of children with ulcerative colitis, coeliac disease, and Crohn’s disease at diagnosis and from the latter two groups after treatment with gluten free diet (GFD) or exclusive enteral nutrition (EEN), respectively. Healthy children (Controls) were also recruited.

Results

138 children were recruited. Plasma but not urinary iFABP was higher in patients with newly diagnosed coeliac disease than Controls (median [Q1, Q3] coeliac disease: 2104 pg/mL 1493, 2457] vs Controls: 938 pg/mL [616, 1140], p = 0.001). Plasma or urinary iFABP did not differ between patients with coeliac on GFD and Controls. Baseline iFABP in plasma decreased by 6 months on GFD (6mo GFD: 1238 pg/mL [952, 1618], p = 0.045). By 12 months this effect was lost, at which point 25% of patients with coeliac disease had detectable gluten in faeces, whilst tissue transglutaminase IgA antibodies (TGA) continued to decrease. At diagnosis, patients with Crohn’s disease had higher plasma iFABP levels than Controls (EEN Start: 1339 pg/mL [895, 1969] vs Controls: 938 pg/mL [616, 1140], p = 0.008). iFABP did not differ according to Crohn’s disease phenotype. Induction treatment with EEN tended to decrease (p = 0.072) iFABP in plasma which was no longer different to Controls (EEN End: 1114 pg/mL [689, 1400] vs Controls: 938 pg/mL [616, 1140], p = 0.164). Plasma or urinary iFABP did not differ in patients with ulcerative colitis from Controls (plasma iFABP, ulcerative colitis: 1309 pg/mL [1005, 1458] vs Controls: 938 pg/mL [616, 1140], p = 0.301; urinary iFABP ulcerative colitis: 38 pg/mg [29, 81] vs Controls: 53 pg/mg [27, 109], p = 0.605).

Conclusions

Plasma, but not urinary iFABP is a candidate biomarker with better fidelity in monitoring compliance during GFD than TGA. The role of plasma iFABP in Crohn’s disease is promising but warrants further investigation.

Trial registration: Clinical Trials.gov, NCT02341248. Registered on 19/01/2015.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12876-022-02334-6.

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.

Fecal S100A12 is associated with future hospitalization and step-up of medical treatment in patients with Crohn's disease in clinical remission: a pilot study

BACKGROUND/AIMS

Fecal S100A12 (FS) and serum S100A12 (SS) have been reported as novel biomarkers that accurately reflect intestinal inflammation. We evaluated if FS and SS in comparison to fecal calprotectin (FC) are associated with poor future outcomes in clinically quiescent Crohn's disease (CD) patients.

METHODS

We prospectively enrolled 49 CD patients in clinical remission (Crohn's Disease Activity Index [CDAI] < 150 for the past 6 months). Patients were followed for a median period of 4.4 years (interquartile range [IQR], 4.3-4.5). The following outcomes were evaluated: clinical relapse, CD-related hospitalization, step-up of medical treatment, and CD-related intestinal resection. Cox proportional-hazard regression model was constructed to assess the association of baseline markers with time-to-event outcomes.

RESULTS

The median levels of baseline FS, FC, and SS were 0.042 mg/kg (IQR, 0.005-0.179), 486.8 mg/kg (IQR, 203.5-886.8) and 1,398.2 ng/mL (IQR, 791.8-2,759.9), respectively. FS correlated with FC (r = 0.689), erythrocyte sedimentation rate (r = 0.524), C-reactive protein (r = 0.499), and albumin (r = -0.446), but not with CDAI (r = 0.045). Interestingly, increased FS (top quartile) was associated with a 4.9-fold increased rate of future CD-related hospitalization (P= 0.009) and a 2.8-fold increased rate of step-up of medical treatment (P= 0.032), whereas increased FC and SS were not. These findings remained significant after adjusting for age, sex, disease duration, current smoking, C-reactive protein, serum albumin, CDAI, and FC, individually.

CONCLUSIONS

In this pilot study, increased FS and not FC or SS, was significantly associated with increased rates of future CD-related hospitalization and step-up of medical treatment among CD patients in clinical remission.

Intestinal ultrasonography and fecal calprotectin for monitoring inflammation of ileal Crohn's disease: two complementary tests

Background/Aims

Tight control of inflammation and adjustment of treatment if activity persists is the current strategy for the management of Crohn’s disease (CD). The usefulness of fecal calprotectin (FC) in isolated involvement of the small intestine in CD is controversial. To assess the usefulness of FC to determine the inflammatory activity detected by intestinal ultrasonography (IUS) in ileal CD.

Methods

Patients with exclusively ileal involvement CD who underwent IUS and an FC were prospectively included. Simple ultrasound index was used to determine inflammatory activity. The usual statistical tests for comparison of diagnostic techniques were used.

Results

One hundred and five patients were included, IUS showed inflammatory activity in 59% of patients and complications in 18.1%. FC showed a significant correlation with IUS in the weak range (Spearman coefficient r=0.502; P<0.001); the area under the receiver operating characteristic curve was 0.79 (95% confidence interval, 0.70–0.88; P<0.001). The FC value that best reflected the activity in IUS was 100 μg/g with sensitivity, specificity, and positive and negative predictive values of 73.0%, 71.4%, 79.3% and 63.8%, respectively. There were no differences in FC concentration between patients with or without transmural complications. The addition of serum C-reactive protein to FC did not improve the ability to assess IUS activity.

Conclusions

FC has a significant correlation with IUS to monitor ileal CD activity. This correlation is weak and it does not allow assessing the presence of CD complications. Both tests should be used in conjunction for tight control of ileal CD. More studies on noninvasive tests in this location are needed.

Fungi: Friend or Foe? A Mycobiome Evaluation in Children With Autism and Gastrointestinal Symptoms

ABSTRACT

Gastrointestinal (GI) symptoms often affect children with autism spectrum disorders (ASD) and GI symptoms have been associated with an abnormal fecal microbiome. There is limited evidence of Candida species being more prevalent in children with ASD. We enrolled 20 children with ASD and GI symptoms (ASD + GI), 10 children with ASD but no GI symptoms (ASD - GI), and 20 from typically developing (TD) children in this pilot study. Fecal mycobiome taxa were analyzed by Internal Transcribed Spacer sequencing. GI symptoms (GI Severity Index [GSI]), behavioral symptoms (Social Responsiveness Scale -2 [SRS-2]), inflammation and fungal immunity (fecal calprotectin and serum dectin-1 [ELISA]) were evaluated. We observed no changes in the abundance of total fungal species (alpha diversity) between groups. Samples with identifiable Candida spp. were present in 4 of 19 (21%) ASD + GI, in 5 of 9 (56%) ASD - GI, and in 4 of 16 (25%) TD children (overall P = 0.18). The presence of Candida spp. did not correlate with behavioral or GI symptoms (P = 0.38, P = 0.5, respectively). Fecal calprotectin was normal in all but one child. Finally, there was no significance in serum dectin-1 levels, suggesting no increased fungal immunity in children with ASD. Our data suggest that fungi are present at normal levels in the stool of children with ASD and are not associated with gut inflammation.

Efficacy of sigmoidoscopy for evaluating disease activity in patients with ulcerative colitis

Background

Endoscopic assessment of disease activity is a key parameter in the management of ulcerative colitis. Whether sigmoidoscopy alone is sufficient to evaluate the disease activity in ulcerative colitis lacks studies.

Methods

We retrospectively analyzed the medical records and endoscopic results of patients with ulcerative colitis followed by colonoscopy in seven tertiary hospitals between January 2012 and December 2018. Endoscopic disease activity was scored using the Mayo endoscopic subscore (MES) and Ulcerative Colitis Endoscopic Index of Severity (UCEIS) for each segment from the colonoscopy images. Concordance was evaluated by comparing the highest MES and UCEIS in the rectosigmoid and proximal regions to confirm the usefulness of sigmoidoscopy.

Results

A total of 500 colonoscopic examinations from 333 patients were enrolled. Only in 7.6% [k(kappa): 0.893, r(Spearman): 0.906, p < 0.001] and 8.6% [k(kappa): 0.890, r(Spearman): 0.914; p < 0.001] of cases, MES and UCEIS scored more severely in the proximal colon. Comparison of active disease (MES ≥ 2) in the rectosigmoid area and the entire colon showed a high concordance rate [k(kappa): 0.899, r(Spearman): 0.904, p < 0.001]. Endoscopic healing (MES = 0) also showed a high concordance rate [k(kappa): 0.882, r(Spearman): 0.887, p < 0.001]. In 38 cases (7.6%) of patients with a higher MES in the proximal area, it was significantly higher in patients with previous extensive colitis.

Conclusions

Sigmoidoscopy and colonoscopy showed a high concordance rate. Therefore, sigmoidoscopy is considered a sufficient substitute for colonoscopy. However, colonoscopy should be considered in patients with previous extensive colitis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12876-022-02178-0.

Usefulness of ultrasonography for small intestinal evaluations in pediatric Crohn's disease

BACKGROUND

Small bowel capsule endoscopy (SBCE) for Crohn's disease is useful; however, its use has some limitations, such as invasiveness when endoscopic assistance is required in patients who cannot swallow the capsule, and the burden of interpretation on a physician. In contrast, intestinal ultrasonography (IUS) is a non-invasive modality for children. The purpose of this study is to evaluate the accuracy of IUS for pediatric patients with established Crohn's disease.

METHODS

Small bowel capsule endoscopy and IUS findings from the same period in pediatric patients with established Crohn's disease were analyzed retrospectively. First, we compared the Lewis score (LS), small bowel endoscopic activity, and IUS findings by small bowel wall thickness (SBWT) and mesenteric lymph node size (MLNS). Second, we compared the performance of IUS findings with those of some biomarkers.

RESULTS

In 22 procedures, SBWT and MLNS were correlated with LS (r = 0.52, P < 0.05, and r = 0.45, P < 0.05, respectively). Small bowel wall thickness, erythrocyte sedimentation rate, and fecal calprotectin levels had the highest accuracy (81.8%, 81.8%, and 81.8%, respectively). The combination of SBWT and MLNS had the highest positive predictive value and negative predictive value (100% and 83.3%, respectively).

CONCLUSIONS

Intestinal ultrasonography findings, including SBWT and MLNS, are useful for monitoring small bowel lesions in pediatric patients with established Crohn's disease. We suggest first evaluating small bowel inflammation by IUS in pediatric patients with Crohn's disease before SBCE because IUS is less invasive than SBCE.

Anti-Microbial Antibody Response is Associated With Future Onset of Crohn's Disease Independent of Biomarkers of Altered Gut Barrier Function, Subclinical Inflammation, and Genetic Risk

BACKGROUND AND AIMS

Altered host immune reactivity to microbial antigens is hypothesized to trigger the onset of Crohn's disease (CD). We aimed to assess whether increased serum anti-microbial antibody response in asymptomatic first-degree relatives (FDRs) of CD patients is an independent risk factor for future CD development.

METHODS

We measured host serum antibody response to 6 microbial antigens at enrollment (Prometheus enzyme-linked immunosorbent assay test: anti-Saccharomyces cerevisiae antibodies immunoglobulin A/immunoglobulin G, anti-OmpC, anti-A4-Fla2, anti-FlaX, anti-CBir1) and derived the sum of positive antibodies (AS). We used samples at enrollment of prospectively followed healthy FDRs from a nested case-control cohort of the Crohn's and Colitis Canada Genetics Environment Microbial Project. Those who later developed CD (n = 77) were matched 1:4 by age, sex, follow-up duration, and geographic location with control FDRs remaining healthy (n = 307). To address our research aims, we fitted a multivariable conditional logistic regression model and performed causal mediation analysis.

RESULTS

High baseline AS (≥2) (43% of cases, 11% of controls) was associated with higher risk of developing CD (adjusted odds ratio, 6.5; 95% confidence interval, 3.4-12.7; P < .001). Importantly, this association remained significant when adjusted for markers of gut barrier function, fecal calprotectin, C-reactive protein, and CD-polygenic risk score, and in subjects recruited more than 3 years before diagnosis. Causal mediation analysis showed that the effect of high AS on future CD development is partially mediated (42%) via preclinical gut inflammation.

CONCLUSIONS

Our results suggest that increased anti-microbial antibody responses are associated with risk of future development of CD, independent of biomarkers of abnormal gut barrier function, subclinical inflammation, and CD-related genetic risks. This suggests that anti-microbial antibody responses are an early predisease event in the development of CD.

Diagnostic Accuracy of Non-Invasive Imaging for Detection of Colonic Inflammation in Patients with Inflammatory Bowel Disease: A Systematic Review and Meta-Analysis

Endoscopy is the gold standard for objective assessment of colonic disease activity in inflammatory bowel disease (IBD). Non-invasive colonic imaging using bowel ultrasound (US), computed tomography (CT), and magnetic resonance imaging (MRI) may have a role in quantifying colonic disease activity. We reviewed the diagnostic accuracy of these modalities for assessment of endoscopically or histopathologically defined colonic disease activity in IBD. We searched Embase, MEDLINE, and the Web of Science from inception to 20 September 2021. QUADAS-2 was used to evaluate the studies' quality. A meta-analysis was performed using a bivariate model approach separately for MRI and US studies only, and summary receiver operating characteristic (ROC) curves were obtained. CT studies were excluded due to the absence of diagnostic test data. Thirty-seven studies were included. The mean sensitivity and specificity for MRI studies was 0.75 and 0.91, respectively, while for US studies it was 0.82 and 0.90, respectively. The area under the ROC curves (AUC) was 0.88 (95% CI, 0.82 to 0.93) for MRI, and 0.90 (95% CI, 0.75 to 1.00) for US. Both MRI and US show high diagnostic accuracy in the assessment of colonic disease activity in IBD patients.

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.

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 utility of faecal and urine biomarkers for small bowel diseases

PURPOSE OF REVIEW

Small bowel diseases pose a unique diagnostic and management challenge and often requires tertiary specialist referral. The use of biomarkers may provide a cheap, noninvasive tool to assess the small bowel in terms of diagnosis, offering a better way to triage referrals and select patients for early management. This review looks at the most recent evidence behind the use of several faecal and urine biomarkers for small bowel diseases.

RECENT FINDINGS

Faecal calprotectin shows the most promise, with evidence to support its role in predicting relapse postsurgery and monitoring treatment response in patients with Crohn's disease. A faecal calprotectin less than 50 μg/g may also be used as a cut-off to triage further investigation. Faecal lactoferrin also appears promising as a marker of small bowel inflammation. A positive faecal immunohistochemistry test precapsule may help to prioritize referrals for obscure bleeding.

SUMMARY

The use of biomarkers in the diagnosis and management of small bowel disease is still controversial and remains unclear. More studies are required to further develop their potential and before societal guidelines can be developed to direct their appropriate use in clinical practice.

Association between Fecal Calprotectin and Mucosal Healing in Pediatric Patients with Crohn's Disease Who Have Achieved Sustained Clinical Remission with Anti-Tumor Necrosis Factor Agents

Background/Aims

Although mucosal healing (MH) is acknowledged as the treatment target in the treat-to-target era, there are limitations on repeated endoscopic examinations, especially in pediatric patients. We aimed to investigate whether fecal calprotectin (FC) could serve as a surrogate marker for the assessment of MH in pediatric patients with Crohn’s disease (CD) who have achieved sustained clinical remission (CR) while treated with anti-tumor necrosis factor (TNF) agents.

Methods

This multicenter retrospective cross-sectional study included pediatric CD patients who had sustained a CR for at least 6 months with anti-TNF agents and who simultaneously underwent ileocolonoscopy and FC tests during follow-up. MH was defined as the absence of any ulcer on ileocolonoscopy.

Results

A total of 131 patients were included in this study. MH was observed in 87 patients (66.7%). The FC level was significantly lower in patients with MH than in those without MH (median 49.0 mg/kg vs 599.0 mg/kg; p<0.001). According to the multivariate logistic regression analysis, FC was the only factor associated with MH (odds ratio, 0.62; 95% confidence interval [CI], 0.52 to 0.73; p<0.001). According to the receiver operating characteristic curve analysis, the optimal cutoff value for FC for the association with MH was <140 mg/kg (area under the curve 0.890, 95% CI 0.829 to 0.951, sensitivity 78.2%, specificity 88.6%, p<0.001).

Conclusions

FC was associated with MH in pediatric patients with CD who had achieved a sustained CR for at least 6 months with anti-TNF agents. In these patients, FC can be used to stratify patients and guide decisions regarding ileocolonoscopy in the treat-to-target era.

A Practical Guide for Faecal Calprotectin Measurement: Myths and Realities

BACKGROUND AND AIMS

Faecal calprotectin [FC] is a valid and non-invasive marker of mucosal inflammation. It is widely used both in clinical trials and in daily clinical practice for patients with inflammatory bowel diseases, but currently no accepted standardization for FC testing is available. Our primary aim here was to provide a clinician's guide containing all the practical information on FC measurement in order to avoid any confounding factors, to minimize intra- and inter-individual variability in dosage, and to ensure a better and adequate interpretation of the results.

METHODS

We conducted a detailed search of the scientific literature in the PubMed/MEDLINE, EMBASE and Cochrane databases up to January 2020 to find all relevant and available articles on pre-analytical and analytical phases of FC measurement.

RESULTS

FC testing is a multi-step procedure consisting of a pre-analytical phase aimed to collect and process the stool sample and a subsequent analytical phase of FC measurement. Several factors can influence test results determining false positives or false negatives. Importantly, this faecal marker is mostly used for patient follow-up and as a predictor of treatment response. For this reason, any altered data may affect the physicians' decisions, negatively impacting on patient management.

CONCLUSIONS

This review provides for the first time practical advice to minimize dosage variability, although further dedicated studies are needed to compare commercially available tests and identify the best tools for the most precise and accurate FC measurement.

Multiomic features associated with mucosal healing and inflammation in paediatric Crohn's disease

BACKGROUND

The gastrointestinal microbiota has an important role in mucosal immune homoeostasis and may contribute to maintaining mucosal healing in Crohn's disease (CD).

AIM

To identify changes in the microbiota, metabolome and protease activity associated with mucosal healing in established paediatric CD METHODS: Twenty-five participants aged 3-18 years with CD, disease duration of over 6 months, and maintenance treatment with biological therapy were recruited. They were divided into a low calprotectin group (faecal calprotectin <100 μg/g, "mucosal healing," n = 11), and a high calprotectin group (faecal calprotectin >100 μg/g, "mucosal inflammation," n = 11). 16S gene-based metataxonomics, 1 H-NMR spectroscopy-based metabolic profiling and protease activity assays were performed on stool samples.

RESULTS

Relative abundance of Dialister species was six-times greater in the low calprotectin group (q = 0.00999). Alpha and beta diversity, total protease activity and inferred metagenomic profiles did not differ between groups. Pentanoate (valerate) and lysine were principal discriminators in a machine-learning model which differentiated high and low calprotectin samples using NMR spectra (R2 0.87, Q2 0.41). Mean relative concentration of pentanoate was 1.35-times greater in the low calprotectin group (95% CI 1.03-1.68, P = 0.036) and was positively correlated with Dialister. Mean relative concentration of lysine was 1.54-times greater in the high calprotectin group (95% CI 1.05-2.03, P = 0.028).

CONCLUSIONS

This multiomic study identified an increase in Dialister species and pentanoate, and a decrease in lysine, in patients with "mucosal healing." It supports further investigation of these as potential novel therapeutic targets in CD.

Defining the Path Forward for Biomarkers to Address Unmet Needs in Inflammatory Bowel Diseases

Despite major advances in the inflammatory bowel diseases field, biomarkers to enable personalized and effective management are inadequate. Disease course and treatment response are highly variable, with some patients experiencing mild disease progression, whereas other patients experience severe or complicated disease. Periodic endoscopy is performed to assess disease activity; as a result, it takes months to ascertain whether a treatment is having a positive impact on disease progression. Minimally invasive biomarkers for prognosis of disease course, prediction of treatment response, monitoring of disease activity, and accurate diagnosis based on improved disease phenotyping and classification could improve outcomes and accelerate the development of novel therapeutics. Rapidly developing technologies have great potential in this regard; however, the discovery, validation, and qualification of biomarkers will require partnerships including academia, industry, funders, and regulators. The Crohn's & Colitis Foundation launched the IBD Biomarker Summit to bring together key stakeholders to identify and prioritize critical unmet needs; prioritize promising technologies and consortium approaches to address these needs; and propose harmonization approaches to improve comparability of data across studies. Here, we summarize the outcomes of the 2018 and 2019 meetings, including consensus-based unmet needs in the clinical and drug development context. We highlight ongoing consortium efforts and promising technologies with the potential to address these needs in the near term. Finally, we summarize actionable recommendations for harmonization, including data collection tools for improved consistency in disease phenotyping; standardization of informed consenting; and development of guidelines for sample management and assay validation. Taken together, these outcomes demonstrate that there is an exceptional alignment of priorities across stakeholders for a coordinated effort to address unmet needs of patients with inflammatory bowel diseases through biomarker science.

Clinical value of fecal calprotectin

Inflammatory bowel disease (IBD) denotes a group of chronic incurable disorders characterized by relapsing-remitting inflammation of the gastrointestinal tract. IBD represents a growing global burden with a prevalence exceeding 0.3% in the Western world and an accelerating incidence in newly industrialized countries. The target for treating IBD has shifted in recent years from symptom control to mucosal healing (MH), which has been shown to be associated with favorable long-term outcomes. The gold standard for ascertaining MH is endoscopic assessment, but endoscopy is limited by its invasive nature, high cost, and finite availability. Surrogate biomarkers are therefore of great utility. Calprotectin, a cytosolic protein derived predominantly from neutrophils, is now widely used in this capacity. Calprotectin is found in various bodily fluids at concentrations proportional to the degree of inflammation, including in feces at levels roughly six times higher than in the blood. Fecal calprotectin (FCP) therefore reflects intestinal inflammation. Various assays, including point-of-care and home-based tests, are now available for measuring FCP. FCP is used for screening purposes, to aid in distinguishing inflammatory from non-inflammatory gastrointestinal conditions like irritable bowel syndrome (IBS), as well as in the monitoring of known IBD. The aims of this review are to provide an overview of the methods used to measure FCP and to review the evidence supporting the use of FCP in IBD, particularly as it pertains to screening, monitoring and predicting disease relapse.

Nested case-control study on risk factors for opportunistic infections in patients with inflammatory bowel disease

BACKGROUND

When opportunistic infections occur, patients with inflammatory bowel disease (IBD) commonly display a significantly increased rate of morbidity and mortality. With increasing use of immunosuppressive agents and biological agents, opportunistic infections are becoming a hot topic in the perspective of drug safety in IBD patients. Despite the well-established role of opportunistic infections in the prognosis of IBD patients, there are few epidemiological data investigating the incidence of opportunis-tic infections in IBD patients in China. Besides, the risk factors for opportunistic infection in Chinese IBD patients remain unclear.

AIM

To predict the incidence of opportunistic infections related to IBD in China, and explore the risk factors for opportunistic infections.

METHODS

A single-center, prospective study of IBD patients was conducted. The patients were followed for up to 12 mo to calculate the incidence of infections. For each infected IBD patient, two non-infected IBD patients were selected as controls. A conditional logistic regression analysis was used to assess associations between putative risk factors and opportunistic infections, which are represented as odds ratios (OR) and 95% confidence intervals (CIs).

RESULTS

Seventy (28.11%) out of 249 IBD patients developed opportunistic infections. Clostridium difficile infections and respiratory syncytial virus infections were found in 24 and 16 patients, respectively. In a univariate analysis, factors such as the severity of IBD, use of an immunosuppressant or immunosuppressants, high levels of fecal calprotectin, and C-reactive protein or erythrocyte sedimentation rate were individually related to a significantly increased risk of opportunistic infection. Multivariate analysis indicated that the use of any immunosuppressant yielded an OR of 3.247 (95%CI: 1.128-9.341), whereas the use of any two immunosuppressants yielded an OR of 6.457 (95%CI: 1.726-24.152) for opportunistic infection. Interestingly, when immunosuppressants were used in combination with infliximab (IFX) or 5-aminosalicylic acid, a significantly increased risk of opportunistic infection was also observed. The relative risk of opportunistic infection was greatest in IBD patients with severe disease activity (OR = 9.090; 95%CI: 1.532-53.941, relative to the remission stage). However, the use of IFX alone did not increase the risk of opportunistic infection.

CONCLUSION

Factors such as severe IBD, elevated levels of fecal calprotectin, and the use of immunosuppressive medications, especially when used in combination, are major risk factors for opportunistic infections in IBD patients. The use of IFX alone does not increase the risk of opportunistic infection.