Fecal S100A12 and fecal calprotectin as noninvasive markers for inflammatory bowel disease in children

Gut Microbiota and Autism Spectrum Disorder: A Neuroinflammatory Mediated Mechanism of Pathogenesis?

Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by impairments in social communication and behavior, frequently accompanied by restricted and repetitive patterns of interests or activities. The gut microbiota has been implicated in the etiology of ASD due to its impact on the bidirectional communication pathway known as the gut-brain axis. However, the precise involvement of the gut microbiota in the causation of ASD is unclear. This study critically examines recent evidence to rationalize a probable mechanism in which gut microbiota symbiosis can induce neuroinflammation through intermediator cytokines and metabolites. To develop ASD, loss of the integrity of the intestinal barrier, activation of microglia, and dysregulation of neurotransmitters are caused by neural inflammatory factors. It has emphasized the potential role of neuroinflammatory intermediates linked to gut microbiota alterations in individuals with ASD. Specifically, cytokines like brain-derived neurotrophic factor, calprotectin, eotaxin, and some metabolites and microRNAs have been considered etiological biomarkers. We have also overviewed how probiotic trials may be used as a therapeutic strategy in ASD to reestablish a healthy balance in the gut microbiota. Evidence indicates neuroinflammation induced by dysregulated gut microbiota in ASD, yet there is little clarity based on analysis of the circulating immune profile. It deems the repair of microbiota load would lower inflammatory chaos in the GI tract, correct neuroinflammatory mediators, and modulate the neurotransmitters to attenuate autism. The interaction between the gut and the brain, along with alterations in microbiota and neuroinflammatory biomarkers, serves as a foundational background for understanding the etiology, diagnosis, prognosis, and treatment of autism spectrum disorder.

Daily Vitamin D3 Versus Stoss Vitamin D3 for Correction of 25OHD Deficiency in Children with Inflammatory Bowel Disease, a Randomised Controlled Trial

INTRODUCTION

Vitamin D deficiency is common in Paediatric Inflammatory Bowel Disease (PIBD) and has been implicated in disease pathogenesis and disease exacerbation. Current guidelines recommend oral vitamin D supplementation when 25OHD levels are below 50 nmol/L. Supplementation comes in two forms: either a daily supplement of a low dose of vitamin D3 (2000 IU) for several months or a single high dose of oral vitamin D3-termed 'stoss' therapy, with no consensus regarding optimum treatment.

METHODS

A randomised controlled trial was conducted in children with a prior diagnosis of PIBD with 25OHD deficiency (< 50 nmol/L), comparing 2000 IU oral D3 daily to a stoss protocol (oral D3 dosage 400,000 IU for 3-12 years of age or 800,000 IU for > 12 years). Children were followed for 12 months, with biochemistry (25OHD, calcium, magnesium, phosphate, parathyroid hormone, haemoglobin, haematocrit, platelets, albumin), stool markers (calprotectin, S100A12), anthropometrics (weight, height, body mass index) as well as clinical disease indices (Paediatric Crohn's Disease Activity Index, Paediatric Ulcerative Colitis Activity Index) and medication use collected at 3, 6, 9 and 12 months.

RESULTS

74 children aged 5-18 years completed the study. Both 2000 IU daily and stoss protocol significantly increased 25OHD from baseline values at 3, 6, 9 and 12 months. One patient randomised to stoss protocol had a 25OHD level of 263 nmol/L with normal serum calcium. There was no difference in biochemical, stool or clinical markers between groups at any time point, nor was there any correlation between 25OHD level and calprotectin or 25OHD level and clinical disease activity scores.

CONCLUSION

Stoss protocol was non-inferior to 2000 IU daily vitamin D3 in raising 25OHD levels at 12 months. There was also no difference between 25OHD levels at 3, 6 and 9 months between groups.

Treatment success in cats with chronic enteropathy is associated with a decrease in fecal calprotectin concentrations

Feline chronic enteropathies (FCE) are challenging to diagnose and monitor for progression and response to treatment. Fecal calprotectin might be a useful non-invasive marker to evaluate clinical endpoints of therapeutic monitoring in FCE. We evaluated fecal calprotectin concentrations in cats with FCE before and after initiation of treatment comprised of immunomodulation and/or dietary intervention. Included were 17 cats with FCE and 18 healthy controls. Clinical investigation of FCE cases included clinical severity grading (feline chronic enteropathy activity index, FCEAI) in all cats, abdominal ultrasonography in 15 cats, and gastrointestinal biopsies in 6 cats. Fecal calprotectin was measured in samples from 12 cats with FCE before treatment, all 17 FCE cats ≥6 weeks after treatment initiation, and all healthy controls. Fecal calprotectin concentrations in FCE cases before treatment (median: 61 μg/g) were significantly higher than after treatment initiation (median: 15 μg/g; p = 0.0098) and compared to controls (median: 6 μg/g; p = 0.0235) and correlated with the FCEAI scores (ρ = 0.54, p = 0.0316). Fecal calprotectin concentrations after treatment initiation were higher with more severe duodenal/proximal jejunal pathology (ρ = 0.83, p = 0.0427) and shorter intervals between sampling time points (ρ = -0.54, p = 0.0250). Relevant decreases in initially increased fecal calprotectin concentrations are seen in cats with FCE on varying treatment strategies that significantly improve or have remission of clinical signs. This supports the utility of fecal calprotectin as a surrogate biomarker to assess disease severity in FCE cases. Further studies need to evaluate fecal calprotectin concentrations longitudinally in relation to mucosal healing vs. clinical response.

Performance of fecal S100A12 as a novel non-invasive diagnostic biomarker for pediatric inflammatory bowel disease: a systematic review and meta-analysis

OBJECTIVE

The incidence and prevalence of inflammatory bowel disease (IBD) in pediatric patients are increasing. Currently, the diagnostic method for IBD is inconvenient, expensive, and difficult. S100A12, a type of calcium-binding protein, detected in the feces of patients with IBD has recently been suggested as a promising diagnostic tool. Hence, the authors aimed to evaluate the accuracy of fecal S100A12 in diagnosing IBD in pediatric patients by performing a meta-analysis.

METHODS

The authors performed a systematic literature search in five electronic databases for eligible studies up to July 15, 2021. Pooled diagnostic accuracies of fecal S100A12 were analyzed as the primary outcomes. Secondary outcomes were standardized mean difference (SMD) of fecal S100A12 levels between IBD and non-IBD groups and a comparison of diagnostic accuracies between fecal S100A12 and fecal calprotectin.

RESULTS

Seven studies comprising 712 children and adolescents (474 non-IBD controls and 238 IBD cases) were included. Fecal S100A12 levels were higher in the IBD group than in the non-IBD group (SMD = 1.88; 95% confidence interval [CI] = 1.19-2.58; p < 0.0001). Fecal S100A12 could diagnose IBD in pediatric patients with a pooled sensitivity of 95% (95% CI = 88%-98%), specificity of 97% (95% CI = 95%-98%), and area under the receiver operating summary characteristics (AUSROC) curve of 0.99 (95% CI = 0.97-0.99). Fecal S100A12 specificity and AUSROC curve values were higher than those of fecal calprotectin (p < 0.05).

CONCLUSION

Fecal S100A12 may serve as an accurate and non-invasive tool for diagnosing pediatric IBD.

Pediatric Ulcerative Colitis in Siblings

This case report discusses a nine-year-old female that presented with abdominal pain, diarrhea, and weight loss, suggestive of inflammatory bowel disease (IBD). She had an older brother previously diagnosed with ulcerative colitis (UC), which raised suspicion that she may have the same condition. CT scan of the abdomen/pelvis showed signs of bowel thickening. Stool studies revealed elevated inflammatory markers including lactoferrin and calprotectin, as well as occult blood. She underwent a colonoscopy and rectal biopsy which further confirmed the diagnosis of ulcerative colitis. This article aims to discuss the clinical presentation, role of genetic factors, diagnostic workup, and therapeutic management of ulcerative colitis in the pediatric population.

Fecal S100A12 concentrations in cats with chronic enteropathies

OBJECTIVES

The aim of this study was to compare fecal S100A12 concentrations in cats diagnosed with chronic enteropathy (CE) with healthy control cats.

METHODS

This was a prospective, cross-sectional study. Forty-nine cats that had gastrointestinal signs for >3 weeks and a complete diagnostic work-up, including bloodwork, abdominal ultrasound and upper and/or lower gastrointestinal endoscopic biopsies, were enrolled into the CE group. Nineteen cats from the CE group were diagnosed with inflammatory bowel disease (IBD) or chronic inflammatory enteropathy (CIE) and 30 with alimentary lymphoma (LSA), based on histopathology results and additional testing with immunohistochemistry or molecular clonality testing with PCR if indicated. Nineteen apparently healthy control cats were included in the study. One fecal sample was collected from each cat and S100A12 concentrations were quantified by an analytically validated in-house ELISA.

RESULTS

Fecal S100A12 concentrations differed between cats with LSA (median 110 ng/g; interquartile range [IQR] 18-548) and control cats (median 4 ng/g; IQR 2-25 [P <0.001]) and between cats with IBD (median 34 ng/g; IQR 15-973) and control cats (P <0.003). S100A12 concentrations in CE cats (median 94 ng/g; IQR 16-548) were statistically significantly higher compared with control cats (P <0.001). The area under the receiver operating characteristic curve (AUROC) to separate healthy cats from CE cats was 0.81 (95% confidence interval [CI] 0.70-0.92) and was statistically significant (P <0.001). The AUROC to separate cats with IBD from cats with LSA was 0.51 (95% CI 0.34-0.68) and was not statistically significant (P = 0.9).

CONCLUSIONS AND RELEVANCE

Fecal S100A12 concentrations at the time of diagnostic investigation were higher in cats with CIE and LSA than in healthy controls but did not differ between cats with LSA and those with CIE/IBD. This study is an initial step toward evaluating a novel non-invasive marker of feline CIE. Further studies are needed to determine the diagnostic utility of fecal S100A12 concentrations in cats with CE, including comparing cats with IBD/CIE and LSA, and to compare them with cats with extra-gastrointestinal disease.

The use of calgranulin-C (S100A12) and fecal zonulin as possible non-invasive markers in children with inflammatory bowel disease: a clinical study

Calgranulin-C (S100A12) and zonulin are considered markers of intestinal inflammation. Our aim was to evaluate fecal S100A12 (f-S100A12) and fecal zonulin (f-zonulin) in children with inflammatory bowel disease (IBD), compared to fecal calprotectin (FC) and serum inflammatory markers. We enrolled children with a previous diagnosis of Crohn's disease (CD) and ulcerative colitis (UC). F-S100A12, f-zonulin, and FC were determined by enzyme-linked immunosorbent assay (ELISA). Endoscopic examination was considered in the patients who underwent ileocolonoscopy within 2 weeks from the enrollment. One hundred seventeen children, 39.3% with CD and 60.7% with UC were enrolled. In both CD and UC, there was a significant direct correlation between FC and f-S100A12 levels. In children with CD and UC, both FC and f-S100A12 correlated with markers of serum inflammation. We found difference in FC and f-S100A12 levels between patients in clinical relapse and remission (FC: mean 1027 ± 818 mcg/ml vs 580 ± 695 mcg/ml respectively, p = 0.028; f-S100A12: mean 66.4 ± 48.2 mcg/ml vs 42.7 ± 40 mcg/ml, respectively p = 0.02). Moreover, we found difference in FC between children with endoscopic inflammation and remission (mean 825 ± 779 mcg/ml vs 473.3 ± 492 mcg/ml, respectively p = 0.048), as well as for f-S100A12 (53 ± 43 mcg/ml vs mean 31 ± 33 mcg/ml vs, respectively p = 0.019). No significant results were found for f-zonulin.

CONCLUSION

Our data suggest that f-S100A12 and FC are both useful non-invasive biomarkers in the management of pediatric IBD in follow up and in monitoring endoscopic and clinical relapse.

WHAT IS KNOWN

• Fecal calprotectin (FC), fecal S100A12 (f- S100A12), and fecal zonulin represent potential noninvasive markers of gut inflammation. • Since S100A12 is predominantly expressed by granulocytes, high levels of f-S100A12 should be more specific for inflammation than FC.

WHAT IS NEW

• FC and f-S100A12 were correlated to each other and despite the lack of correlation with disease location, they were associated with endoscopic inflammation and clinical relapse in children with IBD. • No significant correlations were found between f-zonulin and the inflammatory parameters.

Fecal Calprotectin, Chitinase 3-Like-1, S100A12 and Osteoprotegerin as Markers of Disease Activity in Children with Crohn’s Disease

Fecal calprotectin (FC), chitinase 3-like-1 protein (CHI3L1), S100A12 and osteoprotegerin (OPG) are biomarkers of intestinal inflammation. This cross-sectional study aimed to evaluate these biomarkers in a cohort of children with Crohn’s disease (CD) and compare them with other measures of disease activity. Stool samples from children with CD were used to measure FC, CHI3L1, S100A12 and OPG by enzyme-linked immunosorbent assay. Serum inflammatory markers were measured and pediatric CD disease activity index (PCDAI) scores calculated. The simple endoscopic score for CD (SES-CD) was reported for a subgroup who underwent ileocolonoscopy corresponding with the stool samples. Sixty-five children were recruited. Children in clinical remission had lower FC and CHI3L1 levels than those with active disease (FC: 277 vs. 1648 µg/g, p = 0.012; CHI3L1: 23 vs. 227 ng/g, p = 0.013). FC levels differed between patients with clinically active or inactive isolated ileal CD. Although FC and CHI3L1 levels correlated strongly (r = 0.83), none of the fecal markers correlated well with serum markers. Only FC and OPG correlated with SES-CD scores (r = 0.57 and r = 0.48, respectively). In conclusion, FC correlated with both endoscopic and clinical disease activity and was the only biomarker that differentiated between active and inactive ileal CD. CHI3L1 also predicted clinical disease activity and correlated highly with FC. Further investigation of the role of CHI3L1 is required.

Carboxylesterase-1 Assisted Targeting of HDAC Inhibitors to Mononuclear Myeloid Cells in Inflammatory Bowel Disease

BACKGROUND AND AIMS

Histone deacetylase inhibitors [HDACi] exert potent anti-inflammatory effects. Because of the ubiquitous expression of HDACs, clinical utility of HDACi is limited by off-target effects. Esterase-sensitive motif [ESM] technology aims to deliver ESM-conjugated compounds to human mononuclear myeloid cells, based on their expression of carboxylesterase 1 [CES1]. This study aims to investigate utility of an ESM-tagged HDACi in inflammatory bowel disease [IBD].

METHODS

CES1 expression was assessed in human blood, in vitro differentiated macrophage and dendritic cells, and Crohn's disease [CD] colon mucosa, by mass cytometry, quantitative polymerase chain reaction [PCR], and immunofluorescence staining, respectively. ESM-HDAC528 intracellular retention was evaluated by mass spectrometry. Clinical efficacy of ESM-HDAC528 was tested in dextran sulphate sodium [DSS]-induced colitis and T cell transfer colitis models using transgenic mice expressing human CES1 under the CD68 promoter.

RESULTS

CES1 mRNA was highly expressed in human blood CD14+ monocytes, in vitro differentiated and lipopolysaccharide [LPS]-stimulated macrophages, and dendritic cells. Specific hydrolysis and intracellular retention of ESM-HDAC528 in CES1+ cells was demonstrated. ESM-HDAC528 inhibited LPS-stimulated IL-6 and TNF-α production 1000 times more potently than its control, HDAC800, in CES1high monocytes. In healthy donor peripheral blood, CES1 expression was significantly higher in CD14++CD16- monocytes compared with CD14+CD16++ monocytes. In CD-inflamed colon, a higher number of mucosal CD68+ macrophages expressed CES1 compared with non-inflamed mucosa. In vivo, ESM-HDAC528 reduced monocyte differentiation in the colon and significantly improved colitis in a T cell transfer model, while having limited potential in ameliorating DSS-induced colitis.

CONCLUSIONS

We demonstrate that monocytes and inflammatory macrophages specifically express CES1, and can be preferentially targeted by ESM-HDAC528 to achieve therapeutic benefit in IBD.

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.

Gut Microbiota Is a Potential Biomarker in Inflammatory Bowel Disease

Inflammatory bowel disease (IBD), which includes ulcerative colitis (UC) and Crohn's disease (CD), is characterized by relapse and remission alternately. It remains a great challenge to diagnose and assess disease activity during IBD due to the lack of specific markers. While traditional biomarkers from plasma and stool, such as C-reactive protein (CRP), fecal calprotectin (FC), and S100A12, can be used to measure inflammation, they are not specific to IBD and difficult to determine an effective cut-off value. There is consensus that gut microbiota is crucial for intestinal dysbiosis is closely associated with IBD etiopathology and pathogenesis. Multiple studies have documented differences in the composition of gut microbiota between patients with IBD and healthy individuals, particularly regarding microbial diversity and relative abundance of specific bacteria. Patients with IBD have higher levels of Proteobacteria and lower amounts of Bacteroides, Eubacterium, and Faecalibacterium than healthy individuals. This review summarizes the pros and cons of using traditional and microbiota biomarkers to assess disease severity and treatment outcomes and addresses the possibility of using microbiota-focused interventions during IBD treatment. Understanding the role of microbial biomarkers in the assessment of disease activity and treatment outcomes has the potential to change clinical practice and lead to the development of more personalized therapies.

Gastrointestinal manifestations and their relation to faecal calprotectin in children with autism

Introduction

A common comorbidity in autism spectrum disorder (ASD) children is gastrointestinal problems, and a possible link between active gastrointestinal inflammation and autism has been suggested. Faecal calprotectin (FC) is a non-invasive marker for of gastrointestinal inflammation.

Aim

To study the level of FC as a marker of bowel inflammation in children with ASD and its possible relation to gastrointestinal manifestations.

Material and methods

Calprotectin levels were assessed in stool samples of 40 ASD children. Autism severity was assessed by the Childhood Autism Rating Scale (CARS). Severity of gastrointestinal symptoms was assessed using a modified version of the 6-Item Gastrointestinal Severity Index (6-GSI) questionnaire. A control group of 40 healthy children matched for age and sex with the cases was also included to compare their levels of FC.

Results

Gastrointestinal symptoms were present in 82.5% of children with autism; the most reported offensive stool odour (70%) and the least diarrhoea (17.5%), and a high 6-GSI score was observed in 35% of ASD children. FC levels were elevated in 35% of the cases and in 25% of the control group. The mean levels of FC of cases were significantly elevated compared to levels of controls. FC levels positively correlated with severity of gastrointestinal symptoms (6-GSI) in autistic patients. There was positive correlation between CARS and 6-GSI.

Conclusions

Gastrointestinal manifestations are a common comorbidity in autistic patients. ASD patients have significantly higher FC levels than healthy controls. FC levels are strongly correlated with the severity of gastrointestinal manifestations in ASD children. So, gastrointestinal manifestations among autistic patients could be caused by gastrointestinal inflammation.

Fecal Lactoferrin and Other Putative Fecal Biomarkers in Crohn's Disease: Do They Still Have a Potential Clinical Role?

INTRODUCTION

The need for noninvasive markers of disease activity is mandatory in the assessment of Crohn's disease (CD). The most widely fecal biomarker in CD, despite several limits, is fecal calprotectin. This review aims to elucidate the role, if any, of all other fecal biomarkers, as alternative tools for assessing clinical and endoscopic disease activity, and predict capsule endoscopy findings, response to therapy, disease relapse, and postoperative recurrence. These fecal biomarkers included lactoferrin, S100A12, high mobility group box 1, neopterin, polymorphonuclear neutrophil elastase, fecal hemoglobin, alpha1-antitrypsin, lysozyme, human beta-defensin-2, neutrophil gelatinase-associated lipocalin, matrix metalloproteinase-9, chitinase 3-like-1, M2-pyruvate kinase, myeloperoxidase, and eosinophil proteins.

METHODS

A systematic electronic search in the medical literature was performed up to April 2020. Seventy eligible studies were identified out of 859 citations. Data were grouped according to the assessment of clinical and endoscopic disease activity, capsule endoscopy findings, response to therapy, prediction of relapse, and postoperative recurrence.

RESULTS

The overall correlation between lactoferrin and clinical indexes is poor, while performance is good with endoscopic scores. Lactoferrin seems to represent a reasonably good surrogate marker of response to therapy and to be potentially useful in identifying patients at high risk for endoscopic relapse or postoperative recurrence. The evaluation of the performance of all other fecal markers is limited by the lack of adequate data.

CONCLUSIONS

None of the fecal markers so far represents an acceptable alternative to calprotectin in clinical practice. Fecal lactoferrin is the only possible exception, but a more extensive investigation is still required.

Characterization and engineering of S100A12-heparan sulfate interactions

S100A12, an EF-hand calcium-binding protein, can be secreted by a variety of cell types and plays proinflammatory roles in a number of pathological conditions. Although S100A12 has been shown to interact with heparan sulfate (HS), the molecular detail of the interaction remains unclear. Here we investigate the structural basis of S100A12-HS interaction and how the interaction is regulated by the availability of divalent cations and the oligomeric states of S100A12. We discovered that S100A12-HS interaction requires calcium, while zinc can further enhance binding by inducing S100A12 hexamerization. In contrast, the apo form and zinc-induced tetramer form were unable to bind HS. Guided by the crystal structures of S100A12, we have identified the HS-binding site of S100A12 by site-directed mutagenesis. Characterization of the HS-binding site of S100A12 allowed us to convert the non-HS-binding apo and tetramer forms of S100A12 into a high affinity HS-binding variant by engineering a single-point mutation. Using a HS oligosaccharide microarray, we demonstrated that the N43K mutant displayed markedly enhanced selectivity toward longer HS oligosaccharides compared to the WT S100A12, likely due to the expanded dimension of the reengineered HS-binding site in the mutant. This unexpected finding strongly suggests that HS-binding sites of proteins might be amenable for engineering.

Differential expression and role of S100 proteins in chronic rhinosinusitis

PURPOSE OF REVIEW

Immune system modulators have been under investigation to help elucidate the underlying pathophysiologies of chronic rhinosinusitis (CRS). Psoriasin (S100A7) and calgranulins (S100A8, S100A9, and S100A12) are S100 proteins that have been studied for their immune-mediating responses to pathogens within the context of CRS. This review highlights the expression patterns and proposed roles of S100 proteins in CRS with (CRSwNP) and without (CRSsNP) nasal polyps.

RECENT FINDINGS

Elevated levels of S100A7 and S100A12 were measured in the sinonasal tissues of patients with CRSsNP compared with CRSwNP and controls. S100A12 expression in CRSsNP was significantly correlated to disease severity. Contrastingly, increased S100A8, S100A9, and S100A8/A9 levels were demonstrated in the nasal polyp tissues of patients with CRSwNP compared with those in inferior turbinate and uncinate tissues of patients with CRSsNP and controls.

SUMMARY

The reported differential expression patterns and activities of psoriasin and calgranulins suggest that S100 proteins exert unique and concerted roles in mediating immunity in different subtypes of CRS. These studies will enable further investigations focused on understanding the immune-modulating mechanisms of S100 proteins in different inflammatory signaling pathways and disease phenotypes of CRS toward the pursuit of identifying new biomarkers and targets for improved outcomes.

Comparison of 18F-FDG PET-MR and fecal biomarkers in the assessment of disease activity in patients with ulcerative colitis

OBJECTIVE

To compare the diagnostic performance of fecal biomarkers and ¹⁸F-fludeoxyglucose (¹⁸F-FDG) positron emmision tomography-MR (PET-MR) in the assessment of disease activity in patients with ulcerative colitis.

METHODS

This study was conducted under the framework of a single-center clinical trial (clinicaltrials.gov [NCT03781284]). N = 50 participants were enrolled. Fecal samples were collected before bowel preparation. All patients underwent whole-body ¹⁸F-FDG PET-MR followed by ileocolonoscopy within 24 h. Diagnostic performance of five fecal biomarkers (calprotectin, lactoferrin, polymorphonuclear leukocyte elastase, S100A12 and eosinophil-derived neurotoxin), MR morphological parameters (MRmorph), diffusion-weighted imaging and PET in detecting active disease determined by Rachmilewitz endoscopic activity index (EAI) were evaluated and compared with each other. Correlations between fecal biomarkers, PET and endoscopy were calculated.

RESULTS

According to EAI, n = 38 patients presented with endoscopically active disease (16 mild, 19 moderate and 3 severe). All five biomarkers, PET and MRmorph could differentiate endoscopically active disease from endoscopic remission without significant difference regarding their operating characteristics (accuracies between 0.673 for calprotectin and 0.898 for lactoferrin). In predicting endoscopically moderate to severe disease, PET showed the highest diagnostic performance (accuracy = 0.857) compared to calprotectin and lactoferrin (accuracy = 0.633 and 0.735). PET had also the strongest correlation with endoscopy (ρ = 0.685, p < 0.001), while within fecal biomarkers the levels of lactoferrin and eosinophil-derived neurotoxin correlated significantly with EAI (ρ = 0.423 and 0.528, both p < 0.05).

CONCLUSION

Both fecal biomarkers and PET-MR were excellent non-invasive diagnostic tools in the assessment of disease activity in ulcerative colitis.

ADVANCES IN KNOWLEDGE

Both fecal biomarkers and PET-MR parameters are able to predict endoscopically active disease with comparable diagnostic performance. PET had the highest correlation with endoscopy and outperformed fecal biomarkers in differentiating moderate to severe from mild disease.

Fecal Markers of Inflammation and Disease Activity in Pediatric Crohn Disease: Results from the ImageKids Study

BACKGROUND

Noninvasive and accurate methods to monitor inflammatory bowel disease are required. As a planned ancillary study of the prospective ImageKids cohort, we aimed to assess the performance of fecal calprotectin (FC) with comparison to 3 fecal inflammatory markers; S100A12 (FA12), tumor pyruvate kinase isoenzyme type M2 (FM2PK) and fecal osteoprotegerin (FOPG) as indicators of a number of disease characteristics.

METHODS

The ImageKids study was a multicenter study designed to develop 2 magnetic resonance enterography-based measures for children with Crohn disease (6-18 years old). All patients underwent magnetic resonance enterography, a complete ileocolonoscopic evaluation and provided a fecal sample. Fecal samples were assay for FC, FA12, FM2PK, and FOPG by ELISA.

RESULTS

One-hundred fifty-six children provided 190 fecal samples. Median (interquartile range) for fecal makers were FC, 602 (181-1185) μg/g; FA12, 21 (3-109) μg/g; FM2PK, 16 (2-20) U/mL; and FOPG, 125 (125-312) μg/g. All markers correlated with simple endoscopic severity index for Crohn disease and with other constructs of disease activity, but FC had the highest overall correlations. FA12, however, predicted mucosal healing with significantly higher specificity (87% vs 70%, P = 0.004) and equivalent sensitivity (91% vs 90%) compared to FC.

CONCLUSION

This study has confirmed that FC is useful, and overall best, marker to monitor mucosal inflammation in inflammatory bowel disease. FA12, however, appears to be a more suitable maker for prediction of mucosal healing in children.

Enzyme-Linked Immunosorbent Assay to Measure S100A12 in Fecal Samples of Children and Adults

In recent years there have been numerous attempts to establish reliable and consistent noninvasive biomarkers of gut inflammation. Here we describe the development of an enzyme-linked immunoassay for the measurement of the pro-inflammatory, calcium-binding protein S100A12 in fecal samples.

Damage-associated molecular patterns in inflammatory bowel disease: From biomarkers to therapeutic targets

The chronic inflammatory process underlying inflammatory bowel disease (IBD), comprising Crohn's disease and ulcerative colitis, derives from the interplay of several components in a genetically susceptible host. These components include environmental elements and gut microbiota a dysbiosis. For decades, immune abnormalities have been investigated as critically important in IBD pathogenesis, and attempts to develop effective therapies have predominantly targeted the immune system. Nevertheless, immune events represent only one of the constituents contributing to IBD pathogenesis within the context of the complex cellular and molecular network underlying chronic intestinal inflammation. These factors need to be appreciated within the milieu of non-immune components. Damage-associated molecular patterns (DAMPs), which are essentially endogenous stress proteins expressed or released as a result of cell or tissue damage, have been shown to act as direct pro-inflammatory mediators. Excessive or persistent signalling mediated by such molecules can underlie several chronic inflammatory disorders, including IBD. The release of endogenous DAMPs amplifies the inflammatory response driven by immune and non-immune cells and promotes epigenetic reprogramming in IBD. The effects determine pathologic changes, which may sustain chronic intestinal inflammation and also underlie specific disease phenotypes. In addition to highlighting the potential use of DAMPs such as calprotectin as biomarkers, research on DAMPs may reveal novel mechanistic associations in IBD pathogenesis and is expected to uncover putative therapeutic targets.

Molecular diagnosis and classification of inflammatory bowel disease

INTRODUCTION

Traditional diagnosis and classification of inflammatory bowel diseases (IBDs) have been based on clinical evaluation, laboratory testing, endoscopy, imaging, and histological examinations. With the advancement of medical technology, an increasing number of molecular surrogates are playing a key role in diagnosis, differential diagnosis, assessment of disease activity, prediction of clinical course, and therapeutic response of IBD. Areas covered: The authors review roles of both existing and emerging surrogates including genetic, serological, histologic, and fecal markers in diagnosis and classification of IBD. Comparisons in advantages and disadvantages of different markers have also been discussed. In addition, this review underscores controversial and unclear aspects which need further study. Expert commentary: IBD is characteristic of chronicity, relapse-remission and destructiveness. It is of great importance for clinicians to make an accurate diagnosis and classification. Current and new molecular markers perform well with acceptable sensitivity and specificity. The use of molecular markers in clinical practice needs to be further explored and then generalized. More work is warranted to identify novel useful markers and elucidate how to apply them together with current markers in clinical settings.

Calgranulin C (S100A12) Is Differentially Expressed in Subtypes of Chronic Rhinosinusitis

Background Calgranulin C (S100A12) is an innate immune peptide at the air-mucosal interface associated with neutrophil involvement, which when overexpressed has been implicated as a biomarker of inflammatory diseases. Decreased epithelial expression of certain innate immune peptides has been reported in chronic rhinosinusitis (CRS). We hypothesized that S100A12 is differentially expressed in the sinonasal mucosa of patients with CRS compared to controls and that S100A12 is a potential biomarker of CRS-specific quality of life (QOL) and disease severity. Methods A prospective observational study was conducted which included 70 patients: 17 controls, 28 having CRS without (CRSsNP), and 25 with (CRSwNP) nasal polyps. The expression of S100A12 and human neutrophil elastase (HNE) was assessed in the anterior ethmoid tissues from all patients using enzyme-linked immunosorbent assay (ELISA) and immunohistochemical (IHC) analyses. Disease-specific QOL (Rhinosinusitis Disability Index) and disease severity (computed tomography [CT] and endoscopy) were evaluated and correlated to the expression levels of S100A12. Results S100A12 and HNE were significantly elevated in patients with CRSsNP compared to normal controls ( P < .05 and P < .001, respectively) and patients with CRSwNP ( P < .05 and P < .001, respectively), as measured by ELISA and IHC analyses. Patients with CRS exhibited worse CRS-specific disease severity compared to normal controls ( P < .05), and the increased protein levels of S100A12 were significantly correlated to disease severity, represented by CT scores ( P < .05). Conclusions S100A12 is differentially expressed in CRS subtypes and is significantly elevated in patients with CRSsNP and associated with CRS-specific disease severity.

Predicting inflammatory bowel disease in children with abdominal pain and diarrhoea: calgranulin-C versus calprotectin stool tests

OBJECTIVE

Calgranulin-C (S100A12) is a new faecal marker of inflammation that is potentially more specific for inflammatory bowel disease (IBD) than calprotectin, since it is only released by activated granulocytes. We compared calgranulin-C and calprotectin to see which of the two tests best predicted IBD in children with chronic abdominal pain and diarrhoea.

DESIGN

Delayed-type cross-sectional diagnostic study.

SETTING AND PATIENTS

Previously undiagnosed patients aged 6-17 years, who were seen in paediatric clinics in the Netherlands and Belgium, sent in a stool sample for analysis. Patients with a high likelihood of IBD underwent upper and lower endoscopy (ie, preferred reference test), while those with a low likelihood were followed for 6 months for latent IBD to become visible (ie, alternative reference test). We used Bayesian modelling to correct for differential verification bias.

MAIN OUTCOME MEASURES

Primary outcome was the specificity for IBD using predefined test thresholds (calgranulin-C: 0.75 µg/g, calprotectin: 50 µg/g). Secondary outcome was the test accuracy with thresholds based on receiver operating characteristics (ROC) analysis.

RESULTS

IBD was diagnosed in 93 of 337 patients. Calgranulin-C had significantly better specificity than calprotectin when predefined thresholds were used (97% (95% credible interval (CI) 94% to 99%) vs 71% (95% CI 63% to 79%), respectively). When ROC-based thresholds were used (calgranulin-C: 0.75 µg/g, calprotectin: 400 µg/g), both tests performed equally well (specificity: 97% (95% CI 94% to 99%) vs 98% (95% CI 95% to 100%)).

CONCLUSIONS

Both calgranulin-C and calprotectin have excellent test characteristics to predict IBD and justify endoscopy.

TRIAL REGISTRATION NUMBER

NCT02197780.

The Host Antimicrobial Protein Calgranulin C Participates in the Control of Campylobacter jejuni Growth via Zinc Sequestration

Campylobacter jejuni is a leading cause of bacterially derived gastroenteritis worldwide. Campylobacter is most commonly acquired through the consumption of undercooked poultry meat or through drinking contaminated water. Following ingestion, Campylobacter adheres to the intestinal epithelium and mucus layer, causing toxin-mediated inflammation and inhibition of fluid reabsorption. Currently, the human response to infection is relatively unknown, and animal hosts that model these responses are rare. As such, we examined patient fecal samples for the accumulation of the neutrophil protein calgranulin C during infection with Campylobacter jejuni In response to infection, calgranulin C was significantly increased in the feces of humans. To determine whether calgranulin C accumulation occurs in an animal model, we examined disease in ferrets. Ferrets were effectively infected by C. jejuni, with peak fecal loads observed at day 3 postinfection and full resolution by day 12. Serum levels of interleukin-10 (IL-10) and tumor necrosis factor alpha (TNF-α) significantly increased in response to infection, which resulted in leukocyte trafficking to the colon. As a result, calgranulin C increased in the feces of ferrets at the time when C. jejuni loads decreased. Further, the addition of purified calgranulin C to C. jejuni cultures was found to inhibit growth in a zinc-dependent manner. These results suggest that upon infection with C. jejuni, leukocytes trafficked to the intestine release calgranulin C as a mechanism for inhibiting C. jejuni growth.

S100A12 concentrations and myeloperoxidase activities are increased in the intestinal mucosa of dogs with chronic enteropathies

Background

Intestinal mucosal S100A12 and myeloperoxidase (MPO) are inflammatory biomarkers in humans with inflammatory bowel disease (IBD). However, these biomarkers have not been studied in the intestinal mucosa of dogs with chronic enteropathies (CE), even though dogs with CE have increased S100A12 concentrations in feces and serum. This study investigated mucosal S100A12 concentrations and MPO activities in both dogs with CE and healthy Beagles. ELISA (S100A12 concentrations) and spectrophotometric methods (MPO activity) were used. The associations of both biomarkers with canine IBD activity index (CIBDAI), histopathologic findings, clinical outcome, and serum albumin concentrations were also investigated. We studied intestinal mucosal samples originating from different intestinal regions of 40 dogs with CE and 18 healthy Beagle dogs (duodenum, ileum, colon, and cecum).

Results

Compared with healthy Beagles, mucosal S100A12 concentrations in dogs with CE were significantly higher in the duodenum (p < 0.0001) and colon (p = 0.0011), but not in the ileum (p = 0.2725) and cecum (p = 0.2194). Mucosal MPO activity of dogs with CE was significantly higher in the duodenum (p < 0.0001), ileum (p = 0.0083), colon (p < 0.0001), and cecum (p = 0.0474). Mucosal S100A12 concentrations in the duodenum were significantly higher if the inflammatory infiltrate consisted mainly of neutrophils (p = 0.0439) or macrophages (p = 0.037). Mucosal S100A12 concentrations also showed a significant association with the severity of total histopathological injury and epithelial injury in the colon (p < 0.05). Mucosal MPO activity showed a significant association (p < 0.05) with the severity of total histopathological injury, epithelial injury, and eosinophil infiltration in the duodenum. There was no significant association of both biomarkers with CIBDAI or clinical outcome.

Conclusions

This study showed that both mucosal S100A12 concentrations and MPO activities are significantly increased in the duodenum and colon of dogs with CE; mucosal MPO was also increased in the ileum and cecum. Future research should focus on assessing the clinical utility of S100A12 and MPO as diagnostic markers in dogs with CE.

Fecal Calprotectin

Calprotectin is a 36kDa member of the S100 family of proteins. It is derived predominantly from neutrophils and has direct antimicrobial effects and a role within the innate immune response. Calprotectin is found in various body fluids in proportion to the degree of any existing inflammation and its concentration in feces is about six times that of plasma. Measurement of fecal calprotectin is a useful surrogate marker of gastrointestinal inflammation. It has a high negative predictive value in ruling out inflammatory bowel disease (IBD) in undiagnosed, symptomatic patients and a high sensitivity for diagnosing the disease making it useful as a tool for prioritising endoscopy. In patients with known IBD, fecal calprotectin can be a useful tool to assist management, providing evidence of relapse or mucosal healing to enable therapy to be intensified or reduced. There are a number of commercial calprotectin assays with marked difference in performance as judged by external quality assessment and at present no standardised reference material exists. Various factors may affect results including age, medication and day to day variation. Laboratories should therefore be mindful of the characteristics of their own assay and factors that may affect results.

Surrogate Fecal Biomarkers in Inflammatory Bowel Disease: Rivals or Complementary Tools of Fecal Calprotectin?

BACKGROUND

Current noninvasive methods for assessing intestinal inflammation in inflammatory bowel disease (IBD) remain unsatisfactory. Along with C-reactive protein and erythrocyte sedimentation rate, fecal calprotectin (FC) is the standard test for assessing IBD activity, even though its specificity and accuracy are not optimal and it lacks a validated cutoff. Over the past few decades, several fecal markers released from intestinal inflammatory cells have been investigated in IBD; they are the subject of this systematic review.

METHODS

A systematic electronic search of the English literature up to April 2017 was performed using Medline and the Cochrane Library. Only papers written in English that analyzed fecal biomarkers in IBD were included. In vitro studies, animal studies, studies on blood/serum samples, and studies analyzing FC or fecal lactoferrin alone were excluded.

RESULTS

Out of 1023 citations, 125 eligible studies were identified. Data were grouped according to each fecal marker including S100A12, high-mobility group box 1, neopterin, polymorphonuclear neutrophil elastase, fecal hemoglobin, alpha1-antitrypsin, human neutrophil peptides, neutrophil gelatinase-associated lipocalin, chitinase 3-like-1, matrix metalloproteinase 9, lysozyme, M2-pyruvate kinase, myeloperoxidase, fecal eosinophil proteins, human beta-defensin-2, and beta-glucuronidase. Some of these markers showed a high sensitivity and specificity and correlated with disease activity, response to therapy, and mucosal healing. Furthermore, they showed a potential utility in the prediction of clinical relapse.

CONCLUSIONS

Several fecal biomarkers have the potential to become useful tools complementing FC in IBD diagnosis and monitoring. However, wide variability in their accuracy in assessment of intestinal inflammation suggests the need for further studies.

Reference values of fecal calgranulin C (S100A12) in school aged children and adolescents

BACKGROUND

Calgranulin C (S100A12) is an emerging marker of inflammation. It is exclusively released by activated neutrophils which makes this marker potentially more specific for inflammatory bowel disease (IBD) compared to established stool markers including calprotectin and lactoferrin. We aimed to establish a reference value for S100A12 in healthy children and investigated whether S100A12 levels can discriminate children with IBD from healthy controls.

METHODS

In a prospective community-based reference interval study we collected 122 stool samples from healthy children aged 5-19 years. Additionally, feces samples of 41 children with suspected IBD (who were later confirmed by endoscopy to have IBD) were collected. Levels of S100A12 were measured with a sandwich enzyme-linked immunosorbent assay (ELISA) (Inflamark®). The limit of detection was 0.22 μg/g.

RESULTS

The upper reference limit in healthy children was 0.75 μg/g (90% confidence interval: 0.30-1.40). Median S100A12 levels were significantly higher in patients with IBD (8.00 μg/g [interquartile range (IQR) 2.5-11.6] compared to healthy controls [0.22 μg/g (IQR<0.22); p<0.001]). The best cutoff point based on receiver operating characteristic curve was 0.33 μg/g (sensitivity 93%; specificity 97%).

CONCLUSIONS

Children and teenagers with newly diagnosed IBD have significantly higher S100A12 results compared to healthy individuals. We demonstrate that fecal S100A12 shows diagnostic promise under ideal testing conditions. Future studies need to address whether S100A12 can discriminate children with IBD from non-organic disease in a prospective cohort with chronic gastrointestinal complaints, and how S100A12 performs in comparison with established stool markers.

Role of capsule endoscopy and fecal biomarkers in small-bowel Crohn's disease to assess remission and predict relapse

BACKGROUND AND AIMS

Capsule endoscopy (CE) is the most sensitive test to diagnose small-bowel Crohn's disease (CD). Conventional parameters poorly assess CD remission, and although fecal biomarkers assess colonic activity, their role in assessing remission is uncertain. We report CE findings in small-bowel CD patients in clinical remission compared with fecal biomarkers and standard clinical tools to determine mucosal remission and predict relapses.

METHODS

Forty-three adult small-bowel CD patients in clinical remission (Crohn's Disease Activity Index [CDAI] <150) were prospectively enrolled at 4 academic centers and followed clinically for 12 months. Baseline CE studies were scored using the Capsule Endoscopy Scoring Index (CESI or Lewis score). Baseline and endpoint fecal biomarkers were assayed.

RESULTS

CE findings were normal in 17 patients (40%), mild inflammation in 19 (44%), and moderate to severe inflammation in 7 (16%). Of the 26 patients (60%) with mucosal inflammation on CE, 85% had elevated baseline fecal calprotectin and 77% elevated lactoferrin level. Calprotectin and lactoferrin were normal in all patients without inflammation and elevated in all with moderate to severe inflammation. CESI correlated significantly with calprotectin, lactoferrin, and S100A12 levels but not either CDAI or C-reactive protein. During follow-up, 14% of patients exhibited a clinical flare; all had mucosal inflammation at CE and 83% had elevated baseline calprotectin and lactoferrin levels.

CONCLUSIONS

In small-bowel CD patients in clinical remission, many had ongoing mucosal inflammation assessed by CE and fecal biomarkers. Only some developed a clinical flare during medium-term follow-up. These findings suggest CE and fecal biomarkers are useful in monitoring small-bowel CD progress.

Use of Laboratory Markers in Addition to Symptoms for Diagnosis of Inflammatory Bowel Disease in Children: A Meta-analysis of Individual Patient Data

IMPORTANCE

Blood markers and fecal calprotectin are used in the diagnostic workup for inflammatory bowel disease (IBD) in pediatric patients. Any added diagnostic value of these laboratory markers remains unclear.

OBJECTIVE

To determine whether adding laboratory markers to evaluation of signs and symptoms improves accuracy when diagnosing pediatric IBD.

DATA SOURCES

A literature search of MEDLINE and EMBASE from inception through September 26, 2016. Studies were identified using indexing terms and free-text words related to child, target condition IBD, and diagnostic accuracy.

STUDY SELECTION

Two reviewers independently selected studies evaluating the diagnostic accuracy of more than 1 blood marker or fecal calprotectin for IBD, confirmed by endoscopy and histopathology or clinical follow-up, in pediatric patients with chronic gastrointestinal symptoms. Studies that included healthy controls and/or patients with known IBD were excluded.

DATA EXTRACTION AND SYNTHESIS

Individual patient data from each eligible study were requested from the authors. In addition, 2 reviewers independently assessed quality with Quality Assessment of Diagnostic Accuracy Studies-2.

MEAN OUTCOMES AND MEASURES

Laboratory markers were added as a single test to a basic prediction model based on symptoms. Outcome measures were improvement of discrimination by adding markers as a single test and improvement of risk classification of pediatric patients by adding the best marker.

RESULTS

Of the 16 eligible studies, authors of 8 studies (n = 1120 patients) provided their data sets. All blood markers and fecal calprotectin individually significantly improved the discrimination between pediatric patients with and those without IBD, when added to evaluation of symptoms. The best marker-fecal calprotectin-improved the area under the curve of symptoms by 0.26 (95% CI, 0.21-0.31). The second best marker-erythrocyte sedimentation rate-improved the area under the curve of symptoms by 0.16 (95% CI, 0.11-0.21). When fecal calprotectin was added to the model, the proportion of patients without IBD correctly classified as low risk of IBD increased from 33% to 91%. The proportion of patients with IBD incorrectly classified as low risk of IBD decreased from 16% to 9%. The proportion of the total number of patients assigned to the intermediate-risk category decreased from 55% to 6%.

CONCLUSIONS AND RELEVANCE

In a hospital setting, fecal calprotectin added the most diagnostic value to symptoms compared with blood markers. Adding fecal calprotectin to the diagnostic workup of pediatric patients with symptoms suggestive of IBD considerably decreased the number of patients in the group in whom challenges in clinical decision making are most prevalent.

An update on diagnostic and prognostic biomarkers in inflammatory bowel disease

Diagnosis of the chronic inflammatory bowel diseases relies upon initial recognition of an inflammatory condition, followed by definitive endoscopic, histological and radiological investigations. Various biomarkers are available to assist with initial elucidation of an inflammatory process: these also have important roles after diagnosis in monitoring and ongoing assessment of progress. Areas covered: Various inflammatory markers, serological tests and genetic analyses may be helpful in predicting the course of disease in the coming months. This review provides an update on the current understanding and knowledge about these markers. It also highlights key gaps and identifies aspects that require further study. Expert commentary: Our current approach to the application of non-invasive biomarkers is rudimentary. Further work is required to elucidate the roles of the various markers.

Effect of faecal calprotectin assay variability on the management of inflammatory bowel disease and potential role of faecal S100A12

Aims

To prospectively evaluate whether between-assay variability of different faecal calprotectin (f-Cp) assays influences diagnostic accuracy for inflammatory bowel disease (IBD) in a cohort of patients with confirmed IBD and irritable bowel syndrome (IBS). To also evaluate the diagnostic accuracy of faecal S100A12 (f-S100A12) against f-Cp in the same patient cohort and assess whether f-S100A12 offers additional diagnostic value.

Methods

F-Cp using four commercially available f-Cp assays, f-S100A12 and blood biomarkers were measured in patients, recruited from the local IBD clinic, who had established IBS or active ulcerative colitis (UC) and Crohn’s disease (CD). Diagnostic sensitivities and specificities for each assay and biomarker were calculated and compared.

Results

Median f-Cp levels in all assays were significantly higher in UC (347–884 µg/g; n=28) and CD (377–838 µg/g; n=15) compared with IBS (6–27 µg/g; n=17). Sensitivities and specificities at 50 µg/g were 94%–100% and 82%–100%, respectively. Median f-S100A12 levels were significantly higher in UC (81.0 µg/g; IQR 38.3–159.8) and CD (47.2 µg/g; IQR 5.3–108.9) compared with IBS (0.7 µg/g; IQR 0.5–0.8). At 2.8 µg/g, f-S100A12 had a sensitivity of 97% and specificity of 94%. The blood biomarkers demonstrated sensitivities and specificities of 44%–63% and 80%–92%, respectively.

Conclusions

The diagnostic sensitivity of the calprotectin assays was similar despite inter-kit variability in absolute values. There is a need for f-Cp assay standardisation, but in its absence assay-specific cut-off values may optimise their diagnostic performance. F-S100A12 demonstrated comparable sensitivity and specificity to f-Cp and although a research tool at present, may have a future role to play in the diagnosis and management of these patients.

Selecting children with suspected inflammatory bowel disease for endoscopy with the calgranulin C or calprotectin stool test: protocol of the CACATU study

INTRODUCTION

The introduction of the faecal calprotectin (FC) test to screen children with chronic gastrointestinal complaints has helped the clinician to decide whether or not to subject the patient to endoscopy. In spite of this, a considerable number of patients without inflammatory bowel disease (IBD) is still scoped. Faecal calgranulin C (S100A12) is a marker of intestinal inflammation that is potentially more specific for IBD than FC, as it is exclusively released by activated granulocytes.

OBJECTIVE

To determine whether the specificity of S100A12 is superior to the specificity of FC without sacrificing sensitivity in patients with suspected IBD.

METHODS

An international prospective cohort of children with suspected IBD will be screened with the existing FC stool test and the new S100A12 stool test. The reference standard (endoscopy with biopsies) will be applied to patients at high risk of IBD, while a secondary reference (clinical follow-up) will be applied to those at low risk of IBD. The differences in specificity and sensitivity between the two markers will be calculated.

ETHICS AND DISSEMINATION

This study is submitted to and approved by the Medical Ethics Review Committee of the University Medical Center Groningen (the Netherlands) and the Antwerp University Hospital (Belgium). The results will be disseminated through a peer-reviewed publication, conference presentation and incorporation in the upcoming National Guideline on Diagnosis and Therapy of IBD in Children.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT02197780 .

Biomarkers and non-invasive tests for gastrointestinal mucositis

Gastrointestinal mucositis is a complex inflammatory reaction of the mucous membranes, a side effect of both chemotherapy and radiotherapy. Currently, assessment scales are used to diagnose mucositis. However, a biomarker which would determine whether there is mucositis and thereby establish the severity objectively would be very useful. This will give the opportunity to evaluate studies, to determine risk factors and incidence, and it will make it possible to compare studies. Moreover, this biomarker might improve clinical management for patients. In this paper, we reviewed studies concerning potential biomarkers in blood samples and fecal samples, and potential tests in breath samples and urine samples. We include biomarkers and tests studied in animal models and/or in clinical trials, and discuss the validity, diagnostic accuracy, and applicability.

Association of enteric parasitic infections with intestinal inflammation and permeability in asymptomatic infants of São Tomé Island

The cumulative effect of repeated asymptomatic enteric infections on intestinal barrier is not fully understood in infants. We aimed to evaluate the association between previous enteric parasitic infections and intestinal inflammation and permeability at 24-months of age, in asymptomatic infants of São Tomé Island. A subset of infants from a birth cohort, with intestinal parasite evaluations in at least four points of assessment, was eligible. Intestinal inflammatory response and permeability were assessed using fecal S100A12 and alpha-1-antitrypsin (A1AT), respectively. The cutoff <-1SD for weight-for-length and length-for-age was used to define wasting and stunting. Multivariable linear regression analysis explored if cumulative enteric parasitic infections explained variability of fecal biomarkers, after adjusting for potential confounders. Eighty infants were included. Giardia duodenalis and soil-transmitted helminths (STH) were the most frequent parasites. The median (interquartile range) levels were 2.87 μg/g (2.41-3.92) for S100A12 and 165.1 μg/g (66.0-275.6) for A1AT. Weak evidence of association was found between S100A12 levels and G. duodenalis (p = 0.080) and STH infections (p = 0.089), and between A1AT levels and parasitic infection of any etiology (p = 0.089), at 24-months of age. Significant associations between A1AT levels and wasting (p = 0.006) and stunting (p = 0.044) were found. Previous parasitic infections were not associated with fecal biomarkers at 24 months of age. To summarize, previous asymptomatic parasitic infections showed no association with intestinal barrier dysfunction. Notwithstanding, a tendency toward increased levels of the inflammatory biomarker was observed for current G. duodenalis and STH infections, and increased levels of the permeability biomarker were significantly associated with stunting and wasting.

Fecal biomarkers in inflammatory bowel disease

Over the last two decades, knowledge on fecal biomarkers has substantially increased. Nowadays, these non-invasive markers of inflammation have significant clinical utility in the management of inflammatory bowel disease. Their use informs the decision to perform endoscopy before diagnosis is made right through to influencing therapeutic choices and the need for interval endoscopic assessment. In this review, the roles of two S100 proteins, calprotectin, and S100A12 are described along with that of lactoferrin, in the context of inflammatory bowel disease.

Assessment of disease activity in pediatric ulcerative colitis

To date, we encounter more and more pediatric patients with ulcerative colitis (UC). For yet unclear reasons, UC in pediatric patients seems to be a more aggressive and extensive disease than in their adult counterparts. In the majority of pediatric patients, the disease presents as pancolitis. The severity of the disease is reflected in the high use of corticosteroids and immunosuppressants and a high rate of surgery for medically refractory patients. The means by which to assess disease activity or to accurately predict its course are far from optimal. This review summarizes the current knowledge on the means for assessing UC activity in children. Research for developing new tools by which to monitor and forecast disease activity, are needed in all areas including invasive endoscopy, clinical evaluation, and treatment follow-up.

Paediatric reference ranges for faecal calprotectin: a UK study

Background

Faecal calprotectin has been shown to be a useful non-invasive marker for the diagnosis and monitoring of inflammatory bowel disease in children and adults. Although there are well-established reference ranges for the diagnosis of inflammatory bowel disease in adults, these have been less well studied in children. The objective was to establish reference ranges in our local population.

Method

All faecal calprotectin results from 2011 to 2014 were retrospectively collated and grouped according to patient age. Probability plots were used to determine expected upper limit of normal for each age group, and Mann-Whitney test was used to determine statistical difference between groups.

Results

Upper limit of normal for age groups 1–3.9 years, 4–17.9 years and 18 years plus were 77, 62 and 61  µg/g, respectively. There was a significant difference ( P = 0.0013) between the median calprotectin concentration for the age group 1–3.9 years ( n = 87) and 4–17.9 years ( n = 636) and between the age group 1–3.9 years and 18 years plus ( n = 7953, P = 0.0001), but there was no significant difference between the age groups 4–17.9 years and 18 years plus ( P = 0.4206).

Conclusions

In our local population, faecal calprotectin varies with age. Children aged 1–3.9 years had higher concentrations of faecal calprotectin than adults, but there was no significant difference in faecal calprotectin between older children and adults. This is in agreement with other published studies; however, the faecal calprotectin upper limit of normal calculated for children aged 1–3.9 years was lower than has been observed elsewhere.

Osteoprotegerin: A novel biomarker for inflammatory bowel disease and gastrointestinal carcinoma

Osteoprotegerin (OPG) is a member of the tumor necrosis factor receptor superfamily of proteins. Although initial data illustrated the key role that OPG plays in bone turnover, numerous recent reports indicate that OPG is also an important factor in inflammatory pathways and tumor cell survival. OPG contributes directly to inflammatory processes and has been evaluated as a novel non-invasive biomarker of gut inflammation. Furthermore, OPG affects cell turn-over, differentiation, death, and survival via extracellular pathways, correlating with worse prognosis in inflammatory bowel diseases and several gastrointestinal carcinomas. It is now clear that OPG has multiple functions and characteristics. This review gives an overview of OPG, highlights its roles in different extracellular pathways, and outlines how OPG could be used as a novel non-invasive biological marker in inflammatory bowel diseases and gastrointestinal carcinomas.

Faecal lactoferrin is a useful biomarker for mucosal healing in patients with ulcerative colitis during granulocyte and monocyte adsorptive apheresis therapy

AIM

The study investigated the value of faecal lactoferrin as a follow-up biomarker for mucosal healing of ulcerative colitis during granulocyte and monocyte adsorptive apheresis (GMA) therapy.

METHOD

Patients with ulcerative colitis exhibiting a moderate or severe disease activity with a partial Mayo Score (pMS) of over 4 were enrolled in this study. The patients received 10 courses of GMA therapy. The pMS value and faecal lactoferrin level were monitored and compared with the findings of endoscopy until 12 months after the last dose of GMA therapy.

RESULTS

Twenty patients (male:female 11:9) were enrolled in this study. Twelve had total colitis, while six had left-sided involvement and two had distal proctitis. Thirteen (65.0%) responded to GMA therapy. The faecal lactoferrin levels were significantly decreased in patients who responded to GMA therapy (P < 0.05), whereas the levels did not change in non-responders. Moreover, the faecal lactoferrin levels correlated with the endoscopic findings (r = 0.792, P < 0.01) and pMS scores (r = 0.529, P < 0.01). The correlation coefficients between the faecal lactoferrin levels and mucosal findings were higher than those observed between the pMS score and mucosal findings.

CONCLUSION

The faecal lactoferrin level is a useful biomarker of the mucosal findings in ulcerative colitis. Although endoscopy is the gold standard, the faecal lactoferrin level can be used as a biomarker during GMA therapy in patients with ulcerative colitis.

Calprotectin: Clinical Applications in Pediatrics

As seen over the past 20 years, calprotectin has evolved as a novel, non-invasive biomarker of gastrointestinal (GI) inflammation. We present this review of calprotectin in pediatrics. This article will focus on studies using calprotectin concentrations from different body fluids to monitor inflammation in different disease states and conditions. The ultimate goal of our group is to lay down a foundation as we consider using calprotectin prospectively as a marker of intestinal inflammation that could lead to further testing and possibly a marker of preparedness for feeding. We surveyed all published studies in English of calprotectin in neonates, infants, children, and adolescents through February 2014. We will discuss calprotectin's basic properties and analysis such as characteristics, identification, presence in body fluids, and maturational development. In addition, calprotectin's use in inflammatory diseases exploring both GI and non-GI conditions will be evaluated and compared with other serum markers presently available. Finally, a summary of our findings and discussion of future work that could be undertaken in order to render calprotectin as a more useful monitoring tool to the medical research community will complete the review.

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.

Fecal calprotectin: its scope and utility in the management of inflammatory bowel disease

Gastrointestinal symptoms such as abdominal pain, dyspepsia, and diarrhea are relatively nonspecific and a common cause for seeking medical attention. To date, it is challenging for physicians to differentiate between functional and organic gastrointestinal conditions and it involves the use of serological and endoscopic techniques. Therefore, a simple, noninvasive, inexpensive, and effective test would be of utmost importance in clinical practice. Fecal calprotectin (FC) is considered to be a reliable biomarker that fulfills these criteria. FC can detect intestinal inflammation, and its level correlates well with macroscopic and histological inflammation as detected by colonoscopy and biopsies, respectively. FC has a decent diagnostic accuracy for differentiating organic diseases and functional disorders because of its excellent negative predictive value in ruling out inflammatory bowel disease (IBD) in symptomatic undiagnosed patients. There is accumulating evidence that FC has been effectively used to monitor the natural course of IBD, to predict relapse, and to see the response to treatment. This novel biomarker has the ability to assess mucosal healing (MH), which is a therapeutic goal in IBD management. A literature search was carried out using PubMed with the keywords FC, IBD, intestinal inflammation, and MH. In our review, we provide an overview of the utility and scope of FC as a biomarker in patients with IBD as well as undiagnosed patients with lower gastrointestinal symptoms.

Gut mucosal DAMPs in IBD: from mechanisms to therapeutic implications

Endogenous damage-associated molecular patterns (DAMPs) are released during tissue damage and have increasingly recognized roles in the etiology of many human diseases. The inflammatory bowel diseases (IBD), ulcerative colitis (UC) and Crohn's disease (CD), are immune-mediated conditions where high levels of DAMPs are observed. DAMPs such as calprotectin (S100A8/9) have an established clinical role as a biomarker in IBD. In this review, we use IBD as an archetypal common chronic inflammatory disease to focus on the conceptual and evidential importance of DAMPs in pathogenesis and why DAMPs represent an entirely new class of targets for clinical translation.

Comparison of Fecal Inflammatory Markers in Crohn's Disease

BACKGROUND

Fecal biomarkers are used increasingly to monitor Crohn's disease (CD). However, the relative accuracy of different markers in identifying inflammation has been poorly evaluated. We evaluated fecal calprotectin (FC), lactoferrin (FL), and S100A12 (FS) using endoscopic validation in a prospective study of the progression of CD after intestinal resection.

METHODS

Data were collected from 135 participants in a prospective, randomized, controlled trial aimed at preventing postoperative CD recurrence. Three hundred nineteen stool samples were tested for FC, FL, and FS preoperatively and 6, 12, and 18 months after resection. Colonoscopy was performed at 6 and/or 18 months. Endoscopic recurrence was assessed blindly using the Rutgeerts score. C-reactive protein (CRP) and Crohn's Disease Activity Index (CDAI) were assessed.

RESULTS

FC, FL, and FS concentrations were elevated preoperatively (median: 1347, 40.9, and 8.4 μg/g, respectively). At 6 months postoperatively, marker concentrations decreased (166, 3.0, 0.9 μg/g) and were higher in recurrent disease than remission (275 versus 72 μg/g, P < 0.001; 5.7 versus 1.6 μg/g, P = 0.007; 2.0 versus 0.8 μg/g, P = 0.188). FC > 135 μg/g, FL > 3.4 μg/g, and FS > 10.5 μg/g indicated endoscopic recurrence (score ≥ i2) with a sensitivity, specificity, and negative predictive value (NPV) of 0.87, 0.66, and 91%; 0.70, 0.68, and 81%; 0.91, 0.12, and 71%, respectively. FC and FL correlated significantly with the presence and severity of endoscopic recurrence, whereas FS, CRP and CDAI did not.

CONCLUSIONS

FC was the optimal fecal marker for monitoring disease activity in postoperative CD and was superior to CRP and CDAI. FL offered modest sensitivity for detecting recurrent disease, whereas S100A12 was sensitive but had low specificity and NPV.

Systematic review with meta-analysis: mucosal healing is associated with improved long-term outcomes in Crohn's disease

BACKGROUND

Clinical manifestations of Crohn's disease (CD) do not reliably correlate with endoscopic activity. While treating to achieve clinical remission (CR) has neither proven to improve CD outcomes nor alter the natural disease course, it is unclear whether targeting objective measures like mucosal healing (MH) is associated with improved long-term outcomes.

AIM

To perform a systematic review and meta-analysis comparing long-term outcomes in active CD patients who achieve MH compared to those who do not.

METHODS

We performed a systematic literature search to identify studies with prospective cohorts of active CD patients that included outcomes of patients who achieved MH at first endoscopic assessment (MH1) compared to those who did not. The primary outcome was long-term (≥50 weeks) CR. Secondary outcomes included CD-related surgery-free rate, hospitalisation-free rate and long-term MH rate. Pooled odds ratio (OR) and 95% confidence intervals (CI) were calculated.

RESULTS

Twelve studies with 673 patients met inclusion criteria. Patients achieving MH1 had a pooled OR of 2.80 (95%CI, 1.91-4.10) for achieving long-term CR, 2.22 (95%CI, 0.86-5.69) for CD-related surgery-free rate, and 14.30 (95%CI, 5.57-36.74) for long-term MH. Sensitivity analyses suggested no difference in outcomes if MH1 was achieved on biologics vs. non-biologics. No significant publication bias or heterogeneity was detected.

CONCLUSIONS

Achieving MH1 is associated with increased rates of long-term clinical remission, and maintenance of mucosal healing in active Crohn's disease and may therefore be a reasonable therapeutic target.