Faecal chitinase 3-like-1: a novel biomarker of disease activity in paediatric inflammatory bowel disease

Brown-Kurume Exchange Programs Have Developed Through Many Unexpected Encounters and Relationships

In July 1992, my 24 years of studying abroad in the US as a researcher at Harvard Medical School started. During this period, I met many outstanding scholars who conducted some of the world's leading research projects. In particular, the opportunity to collaborate with Dr. Jack A. Elias, Professor and Dean Emeritus of the Faculty of Medicine at Brown University, on a project focusing on a molecule called Chitinase 3-like 1 was very helpful to my career, and eventually led to my current position as Professor in charge of international medical exchange at Kurume University School of Medicine. By strengthening the foundation of our exchange programs and actively promoting international joint research projects, I would like to raise the global name recognition of Kurume University.

Recently Updated Role of Chitinase 3-like 1 on Various Cell Types as a Major Influencer of Chronic Inflammation

Chitinase 3-like 1 (also known as CHI3L1 or YKL-40) is a mammalian chitinase that has no enzymatic activity, but has the ability to bind to chitin, the polymer of N-acetylglucosamine (GlcNAc). Chitin is a component of fungi, crustaceans, arthropods including insects and mites, and parasites, but it is completely absent from mammals, including humans and mice. In general, chitin-containing organisms produce mammalian chitinases, such as CHI3L1, to protect the body from exogenous pathogens as well as hostile environments, and it was thought that it had a similar effect in mammals. However, recent studies have revealed that CHI3L1 plays a pathophysiological role by inducing anti-apoptotic activity in epithelial cells and macrophages. Under chronic inflammatory conditions such as inflammatory bowel disease and chronic obstructive pulmonary disease, many groups already confirmed that the expression of CHI3L1 is significantly induced on the apical side of epithelial cells, and activates many downstream pathways involved in inflammation and carcinogenesis. In this review article, we summarize the expression of CHI3L1 under chronic inflammatory conditions in various disorders and discuss the potential roles of CHI3L1 in those disorders on various cell types.

Potential Role of Macrophage Polarization in the Progression of Hunner-Type Interstitial Cystitis

BACKGROUND

Hunner-type interstitial cystitis (HIC) is a chronic inflammatory condition of the bladder. However, it remains unclear whether there is a causal relationship between the presence of Hunner lesions and seemingly normal-appearing areas in the bladder (non-Hunner lesions). This study aimed to investigate the fundamental aspects of HIC by examining potential genetic differences between Hunner and non-Hunner lesions and elucidate their role as potential markers in the progression and suppression of the disease.

METHODS

This cross-sectional study enrolled patients with HIC (n = 10) who underwent supratrigonal cystectomy along with augmentation cystoplasty. Full-thickness bladder tissue was collected from Hunner and non-Hunner lesions in the same patient. Normal bladder tissue biopsies were also obtained as controls. Whole transcriptome analysis was performed to analyze the gene expression patterns and immune cell populations.

RESULTS

The mucosal layers of patients exhibited similar pathway dysregulation across Hunner and non-Hunner lesions, with immunerelated pathways being prominently affected. In the mucosal layer, genes related to anti-inflammatory and immune suppression were downregulated in Hunner lesions compared to non-Hunner lesions. Moreover, in Hunner lesions, genes related to macrophage differentiation and polarization, such as VSIG4, CD68, MAFB, and LIRB4, were downregulated. The cell fraction of M2 macrophages was found to decrease in Hunner lesions. Immunohistochemical staining revealed an elevated fraction of M1 macrophages and a reduced fraction of M2 macrophages in Hunner lesions compared to those in non-Hunner lesions. In the muscular layer, transcriptomic evidence of muscle thickness was observed in both Hunner and non-Hunner lesions; however, the difference was not significant.

CONCLUSION

Hunner lesions showed a reduced expression of anti-inflammatory and immunosuppressive factors compared to non-Hunner lesions, along with alterations in immune cell populations. This study suggests the possibility that macrophage polarization is related to the progression from non-Hunner lesions to Hunner lesions, suggesting its relevance to the characteristics of autoimmune diseases.

Location-based prediction model for Crohn's disease regarding a novel serological marker, anti-chitinase 3-like 1 autoantibodies

BACKGROUND

Defective neutrophil regulation in inflammatory bowel disease (IBD) is thought to play an important role in the onset or manifestation of IBD, as it could lead to damage of the intestinal mucosal barrier by the infiltration of neutrophils in the inflamed mucosa and the accumulation of pathogens. Like neutrophils in the context of innate immune responses, immunoglobulin A (IgA) as an acquired immune response partakes in the defense of the intestinal epithelium. Under normal conditions, IgA contributes to the elimination of microbes, but in connection with the loss of tolerance to chitinase 3-like 1 (CHI3L1) in IBD, IgA could participate in CHI3L1-mediated improved adhesion and invasion of potentially pathogenic microorganisms. The tolerance brake to CHI3L1 and the occurrence of IgA autoantibodies to this particular target, the exact role and underlying mechanisms of CHI3L1 in the pathogenesis of IBD are still unclear.

AIM

To determine the predictive potential of Ig subtypes of a novel serological marker, anti-CHI3L1 autoantibodies (aCHI3L1) in determining the disease phenotype, therapeutic strategy and long-term disease course in a prospective referral cohort of adult IBD patients.

METHODS

Sera of 257 Crohn's disease (CD) and 180 ulcerative colitis (UC) patients from a tertiary IBD referral center of Hungary (Division of Gastroenterology, Department of Internal Medicine, Faculty of Medicine, University of Debrecen) were assayed for IgG, IgA, and secretory IgA (sIgA) type aCHI3L1 by enzyme-linked immunosorbent assay using recombinant CHI3L1, along with 86 healthy controls (HCONT).

RESULTS

The IgA type was more prevalent in CD than in UC (29.2% vs 11.1%) or HCONT (2.83%; P < 0.0001 for both). However, sIgA subtype aCHI3L1 positivity was higher in both CD and UC patients than in HCONT (39.3% and 32.8% vs 4.65%, respectively; P < 0.0001). The presence of both IgA and sIgA aCHI3L1 antibodies was associated with colonic involvement (P < 0.0001 and P = 0.038, respectively) in patients with CD. Complicated disease behavior at sample procurement was associated with aCHI3L1 sIgA positivity (57.1% vs 36.0%, P = 0.009). IgA type aCH3L1 was more prevalent in patients with frequent relapse during the disease course in the CD group (46.9% vs 25.7%, P = 0.005). In a group of patients with concomitant presence of pure inflammatory luminal disease and colon involvement at the time of diagnosis, positivity for IgA or sIgA type aCH3L1 predicted faster progression towards a complicated disease course in time-dependent models. This association disappeared after merging subgroups of different disease locations.

CONCLUSION

CHI3L1 is a novel neutrophil autoantigenic target in IBD. The consideration of antibody classes along with location-based prediction may transform the future of serology in IBD.

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.

Children With Cystic Fibrosis Have Elevated Levels of Fecal Chitinase-3-like-1

Although chitinase-3-like-1 (CHI3L1), predominately produced by epithelial cells and macrophages, is relevant to pulmonary disease in cystic fibrosis (CF), fecal levels have not yet been assessed in children with CF. Fecal CHI3L1 was measured with a commercial immunoassay using fecal samples provided by children with CF and healthy control (HC) children. Higher median (interquartile range) fecal CHI3L1 levels were seen in the 52 children with CF than in the 35 controls: 15.97 (3.34-50.53) ng/g versus 2.93 (2.13-9.27) ng/g ( P = 0.001). Fecal CHI3LI did not differ according to sex. In the children with CF, fecal CHI3L1 levels did not correlate with growth parameters nor were the levels affected by pancreatic insufficiency. Children with CF had higher fecal CHI3L1 levels, suggesting underlying gut inflammation. Further work is required to confirm the current findings and to ascertain the longer-term significance of elevated CHI3L1.

Salmonella enterica serovar Typhimurium chitinases modulate the intestinal glycome and promote small intestinal invasion

Salmonella enterica serovar Typhimurium (S. Typhimurium) is one of the leading causes of food-borne illnesses worldwide. To colonize the gastrointestinal tract, S. Typhimurium produces multiple virulence factors that facilitate cellular invasion. Chitinases have been recently emerging as virulence factors for various pathogenic bacterial species, and the S. Typhimurium genome contains two annotated chitinases: STM0018 (chiA) and STM0233. However, the role of these chitinases during S. Typhimurium pathogenesis is unknown. The putative chitinase STM0233 has not been studied previously, and only limited data exists on ChiA. Chitinases typically hydrolyze chitin polymers, which are absent in vertebrates. However, chiA expression was detected in infection models and purified ChiA cleaved carbohydrate subunits present on mammalian surface glycoproteins, indicating a role during pathogenesis. Here, we demonstrate that expression of chiA and STM0233 is upregulated in the mouse gut and that both chitinases facilitate epithelial cell adhesion and invasion. S. Typhimurium lacking both chitinases showed a 70% reduction in invasion of small intestinal epithelial cells in vitro. In a gastroenteritis mouse model, chitinase-deficient S. Typhimurium strains were also significantly attenuated in the invasion of small intestinal tissue. This reduced invasion resulted in significantly delayed S. Typhimurium dissemination to the spleen and the liver, but chitinases were not required for systemic survival. The invasion defect of the chitinase-deficient strain was rescued by the presence of wild-type S. Typhimurium, suggesting that chitinases are secreted. By analyzing N-linked glycans of small intestinal cells, we identified specific N-acetylglucosamine-containing glycans as potential extracellular targets of S. Typhimurium chitinases. This analysis also revealed a differential abundance of Lewis X/A-containing glycans that is likely a result of host cell modulation due to the detection of S. Typhimurium chitinases. Similar glycomic changes elicited by chitinase deficient strains indicate functional redundancy of the chitinases. Overall, our results demonstrate that S. Typhimurium chitinases contribute to intestinal adhesion and invasion through modulation of the host glycome.

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.

Chitinases and Chitinase-Like Proteins as Therapeutic Targets in Inflammatory Diseases, with a Special Focus on Inflammatory Bowel Diseases

Chitinases belong to the evolutionarily conserved glycosyl hydrolase family 18 (GH18). They catalyze degradation of chitin to N-acetylglucosamine by hydrolysis of the β-(1-4)-glycosidic bonds. Although mammals do not synthesize chitin, they possess two enzymatically active chitinases, i.e., chitotriosidase (CHIT1) and acidic mammalian chitinase (AMCase), as well as several chitinase-like proteins (YKL-40, YKL-39, oviductin, and stabilin-interacting protein). The latter lack enzymatic activity but still display oligosaccharides-binding ability. The physiologic functions of chitinases are still unclear, but they have been shown to be involved in the pathogenesis of various human fibrotic and inflammatory disorders, particularly those of the lung (idiopathic pulmonary fibrosis, chronic obstructive pulmonary disease, sarcoidosis, and asthma) and the gastrointestinal tract (inflammatory bowel diseases (IBDs) and colon cancer). In this review, we summarize the current knowledge about chitinases, particularly in IBDs, and demonstrate that chitinases can serve as prognostic biomarkers of disease progression. Moreover, we suggest that the inhibition of chitinase activity may be considered as a novel therapeutic strategy for the treatment of IBDs.

A Review of Selected IBD Biomarkers: From Animal Models to Bedside

Inflammatory bowel disease (IBD) is a dysregulated inflammatory condition induced by multiple factors. The etiology of IBD is largely unknown, and the disease progression and prognosis are variable and unpredictable with uncontrolled disease behavior. Monitoring the status of chronic colitis closely is challenging for physicians, because the assessment of disease activity and severity require invasive methods. Using laboratory biomarkers may provide a useful alternative to invasive methods in the diagnosis and management of IBD. Furthermore, patients with ulcerative colitis or Crohn’s disease are also at risk of developing cancer. Annual colonoscopies can help lower the risk for developing colorectal cancer. However, laboratory biomarkers may also be helpful as non-invasive indicators in predicting treatment responses, improving prognosis, and predicting possible tumors. This review addresses selected laboratory biomarkers (including ANCA, chitinase 3-like 1, S100A12/RAGE, calprotectin, and TNF/TNFR2), which are identified by utilizing two well-accepted animal models of colitis, dextran sodium sulfate-induced and T cell receptor alpha knockout colitis models. In addition to being useful for monitoring disease severity, these biomarkers are associated with therapeutic strategies. The factors may regulate the initiation and perpetuation of inflammatory factors in the gut.

Laboratory Assessment of Disease Activity in Pediatric Patients with Inflammatory Bowel Disease: What’s New?

Laboratory tests are an integral part of both the diagnostic and follow-up algorithm of patients with inflammatory bowel disease (IBD). Their advantages over other non-invasive methods for assessing disease activity are greater objectivity than clinical activity indices and imaging studies. This review aims to analyze shortly the most common laboratory tests used to assess disease activity in pediatric patients with IBD. In addition to the conventional blood and serum markers that are not specific for gut inflammation, although routinely used, we also reviewed the established fecal markers such as calprotectin, lactoferrin, M2-pyruvate kinase, osteoprotegerin, HMGB1, chitinase 3-like 1, and the promising non-coding microRNA. In conclusion, neither marker is unique to the pediatric IBD. More clinical data are required to assess biomarkers’ full potential for diagnosis, management, and follow-up of pediatric IBD patients.

Biomarkers of Inflammation in Inflammatory Bowel Disease: How Long before Abandoning Single-Marker Approaches?

BACKGROUND

Inflammatory bowel disease (IBD) is a chronically relapsing disease with a continuous need for proactive monitoring to decide appropriate treatments and follow-up strategies. To date, gastrointestinal endoscopy with histologic examination of biopsies and contrast-enhanced imaging are mandatory techniques for the diagnosis and the activity assessment of IBD.

SUMMARY

In recent decades, many research efforts in the IBD field have been placed on finding non-invasive and reliable biomarkers of disease burden that can be easily tested in body fluids without impacting the quality of life of patients. Unfortunately, the ideal biomarker is yet to be discovered and recent studies have investigated the possibility to increase the accuracy of such measurements by combining different markers. In this review, we provide an update about the current knowledge on biomarkers of intestinal inflammation in IBD, focussing on disease diagnosis, correlation with endoscopic findings, and prediction of relapse. We also summarize composite scores of clinical and laboratory markers that have been recently proposed in various scenarios of disease activity. Key Messages: To date, only C-reactive protein and faecal calprotectin can be considered reliable markers of disease activity with demonstrated utility in IBD management. The combination of different parameters has recently shown higher accuracy and might substitute single-marker approaches in the future of research and clinical practice.

Chitinase-3 like-protein-1 function and its role in diseases

Non-enzymatic chitinase-3 like-protein-1 (CHI3L1) belongs to glycoside hydrolase family 18. It binds to chitin, heparin, and hyaluronic acid, and is regulated by extracellular matrix changes, cytokines, growth factors, drugs, and stress. CHI3L1 is synthesized and secreted by a multitude of cells including macrophages, neutrophils, synoviocytes, chondrocytes, fibroblast-like cells, smooth muscle cells, and tumor cells. It plays a major role in tissue injury, inflammation, tissue repair, and remodeling responses. CHI3L1 has been strongly associated with diseases including asthma, arthritis, sepsis, diabetes, liver fibrosis, and coronary artery disease. Moreover, following its initial identification in the culture supernatant of the MG63 osteosarcoma cell line, CHI3L1 has been shown to be overexpressed in a wealth of both human cancers and animal tumor models. To date, interleukin-13 receptor subunit alpha-2, transmembrane protein 219, galectin-3, chemo-attractant receptor-homologous 2, and CD44 have been identified as CHI3L1 receptors. CHI3L1 signaling plays a critical role in cancer cell growth, proliferation, invasion, metastasis, angiogenesis, activation of tumor-associated macrophages, and Th2 polarization of CD4⁺ T cells. Interestingly, CHI3L1-based targeted therapy has been increasingly applied to the treatment of tumors including glioma and colon cancer as well as rheumatoid arthritis. This review summarizes the potential roles and mechanisms of CHI3L1 in oncogenesis and disease pathogenesis, then posits investigational strategies for targeted therapies.

The Ulcerative Colitis Response Index for Detection of Mucosal Healing in Patients Treated With Anti-tumour Necrosis Factor

BACKGROUND

Surrogate markers that accurately detect mucosal healing [MH] in patients with ulcerative colitis [UC] are urgently needed. Several stool neutrophil-related proteins are currently used as biomarkers for MH. However, the sensitivity and specificity are not sufficient to avoid unnecessary endoscopic evaluations.

METHODS

Novel serum neutrophil-related markers (neutrophil gelatinase B-associated lipocalin and matrix metalloproteinase-9 [NGAL-MMP-9 complex], cathelicidin LL-37 and chitinase 3-like 1 [CHI3L1]), together with C-reactive protein [CRP] and neutrophil counts were studied. Serum samples were obtained from 176 anti-tumour necrosis factor [anti-TNF]-treated UC patients (145 infliximab [IFX] and 31 adalimumab [ADM]) at baseline and after a median of 9.5 weeks. All patients had active disease prior to treatment (Mayo endoscopic subscore [MES] ≥ 2), and MH was defined as MES ≤ 1. Serum was also obtained from 75 healthy controls. Binary logistic regression analysis was used to generate the Ulcerative Colitis Response Index [UCRI]. The performance of individual markers and UCRI was tested with receiver operating characteristic analysis.

RESULTS

All neutrophil-related markers were significantly higher in active UC patients compared to healthy controls. In the IFX cohort, CRP, NGAL-MMP-9, CHI3L1 and neutrophil count decreased significantly after treatment and all marker levels were significantly lower in healers compared to non-healers following IFX. In the ADM cohort, CRP, NGAL-MMP-9, CHI3L1 and neutrophil count decreased significantly only in healers. UCRI [including CRP, CHI3L1, neutrophil count and LL-37] accurately detected MH in both IFX-treated (area under the curve [AUC] = 0.83) and ADM-treated [AUC = 0.79] patients.

CONCLUSIONS

The new UCRI index accurately detects MH after treatment with IFX and ADM. This panel is useful for monitoring MH in UC patients under anti-TNF treatment.

PODCAST

This article has an associated podcast which can be accessed at https://academic.oup.com/ecco-jcc/pages/podcast.

Identification of Chitinase-3-Like Protein 1 as a Novel Neutrophil Antigenic Target in Crohn's Disease

BACKGROUND AND AIMS

There is an increasing incidence of inflammatory bowel disease [IBD]. Autoimmune responses are involved in the pathophysiology of IBD, but their underlying pathways and target antigens have not yet been fully elucidated.

METHODS

Autoantigenic targets in IBD were identified after separation of whole cell proteins isolated from neutrophils using two-dimensional electrophoresis and matrix assisted laser desorption ionization - time of flight mass spectrometry-based protein identification of the spots that displayed Western blotting signals with anti-neutrophil cytoplasmic antibody-positive sera. The prevalence of IgG, IgA and secretory IgA [sIgA] to chitinase 3-like protein 1 [CHI3L1] was analysed by enzyme-linked immunosorbent assays using recombinant CHI3L1 in 110 patients with Crohn's disease [CD], 95 with ulcerative colitis [UC], 126 with coeliac disease [CeD] and 86 healthy controls [HCs].

RESULTS

The 18-glycosylhydrolase family member CHI3L1 was identified as a neutrophil autoantigenic target. CD patients displayed significantly higher levels of IgG to CHI3L1 than patients with UC and CeD (p < 0.0001, respectively). IgA and sIgA to CHI3L1 was significantly higher in CD than in UC, CeD and HCs [p < 0.0001, respectively]. IgA and sIgA to CHI3L1 demonstrated the highest prevalence in CD [25.5%, 28/110; and 41.8%%, 46/110] compared to HCs [2.3%, 2/86; and 4.7%%, 4/86; p = 0.0015 and p < 0.0001] and are associated with a more complicated progression of CD.

CONCLUSION

CHI3L1 is a novel neutrophil autoantigenic target in CD. IgA and sIgA to CHI3L1 may serve as novel markers for CD and may facilitate the serological diagnosis of IBD.

Quantitative Proteomic Analysis Reveals the Deregulation of Nicotinamide Adenine Dinucleotide Metabolism and CD38 in Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) has become a major health challenge worldwide. However, the precise etiological and pathophysiological factors involved in IBD remain unclear. Proteomics can be used for large-scale protein identification analysis. In the current study, using tandem mass tag- (TMT-) based shotgun proteomics, proteomic differences between intestinal tissue from health controls, patients with Crohn's disease (CD), and patients with ulcerative colitis (UC) were compared. Proteins with fold change >2 or <0.5 and P value < 0.05 between groups were considered differentially expressed. ProteinAtlas was used to analyze the tissue specificity of differentially expressed proteins (DEPs). Reactome pathway analysis was applied to cluster functional pathways. A total of 4786 proteins were identified, with 59 proteins showing higher levels and 43 showing lower levels in patients with IBD than in controls. Seventeen proteins, including angiotensin converting enzyme 2 (ACE2) and angiotensin converting enzyme 1 (ACE), showed higher levels in CD than in UC. Several novel proteins such as CD38, chitinase 3-like 1 (CHI3L1), olfactomedin 4 (OLFM4), and intelectin 1 were screened out between patients with IBD and controls. When proteins with fold change >1.2 or <0.84 and P value < 0.05 between groups were considered differentially expressed, the expression of 10 proteins, including CD38, involved in the nicotinamide adenine dinucleotide (NAD) metabolism and signaling pathway showed significant changes in IBD. Using the NCBI GEO database, we confirmed increased CD38 mRNA expression in patients with UC and in mouse colitis models. Protein CD38 expression was higher in CD and UC than in normal controls. CD38 expression was higher in inflamed tissues than in noninflamed tissues, and CD38 was located in F4/80-positive cells. Our study may provide novel insights into the molecular pathogenesis of IBD. Further studies are required on the role of NAD metabolism and CD38 in intestinal inflammation.

Usefulness of fecal calprotectin by monoclonal antibody testing in adult Japanese with inflammatory bowel diseases: a prospective multicenter study

Background/Aims

Noninvasive objective monitoring is advantageous for optimizing treatment strategies in patients inflammatory bowel disease (IBD). Fecal calprotectin (FCP) is superior to traditional biomarkers in terms of assessing the activity in patients with IBD. However, there are the differences among several FCP assays in the dynamics of FCP. In this prospective multicenter trial, we investigated the usefulness of FCP measurements in adult Japanese patients with IBD by reliable enzyme immunoassay using a monoclonal antibody.

Methods

We assessed the relationship between FCP levels and disease or endoscopic activity in patients with ulcerative colitis (UC, n=64) or Crohn’s disease (CD, n=46) compared with healthy controls (HCs, n=64).

Results

FCP levels in UC patients strongly correlated with the Disease Activity Index (r_s=0.676, P<0.0001) and Mayo endoscopic subscore (MES; r_s=0.677, P<0.0001). FCP levels were significantly higher even in patients with inactive UC or CD compared with HCs (P=0.0068, P<0.0001). The optimal cutoff value between MES 1 and 2 exhibited higher sensitivity (94.1%). FCP levels were significantly higher in active UC patients than in inactive patients (P<0.001), except those with proctitis. The Crohn’s Disease Activity Index tended to correlate with the FCP level (r_s=0.283, P=0.0565).

Conclusions

Our testing method using a monoclonal antibody for FCP was well-validated and differentiated IBD patients from HCs. FCP may be a useful biomarker for objective assessment of disease activity in adult Japanese IBD patients, especially those with UC.

Chitin, chitinases, and chitin lectins: Emerging roles in human pathophysiology

Chitin is a simple β-linked repeating sugar polymer prominent in the building block structures of a wide variety of organisms, from the yeast cell wall to the exoskeleton and shells of arthropods and other forms of invertebrate life. It had previously been assumed that vertebrates did not contain chitins. However, chitin and chitinases are now documented to occur in vertebrate tissues. Chitin, chitinases and particularly chitinase-like proteins are involved in important human pathologies, though the mechanisms by which these function is unknown. These chitinase-like proteins bind to chitin and function as chitin lectins in that they bind to chitin but have lost the ability to degrade it. Emphasis is placed on one of the chitinase-like proteins, CHI3L1, that has acquired wide clinical importance. The purpose of this review is to place an array of bewildering observations associated with various human disorders into a framework, particularly the pathologies of the human gastro-intestinal tract. A reasonably cohesive story may eventually emerge.

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.

An update on diagnostic and prognostic biomarkers in inflammatory bowel disease

INTRODUCTION

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.

Novel Biomarkers and the Future Potential of Biomarkers in Inflammatory Bowel Disease

There is increasing importance placed upon noninvasive assessment of gut inflammation. These tools are likely to be the key in differentiating intestinal inflammatory disease from functional disorders and in monitoring the response to intervention in individuals with known inflammatory conditions. Although various noninvasive markers are currently available, they have limitations and do not provide ideal utility. This review focuses on emerging markers of gut inflammation, highlighting the potential of specific markers.

Chitinase 3-like 1 induces survival and proliferation of intestinal epithelial cells during chronic inflammation and colitis-associated cancer by regulating S100A9

Many host-factors are inducibly expressed during the development of inflammatory bowel disease (IBD), each having their unique properties, such as immune activation, bacterial clearance, and tissue repair/remodeling. Dysregulation/imbalance of these factors may have pathogenic effects that can contribute to colitis-associated cancer (CAC). Previous reports showed that IBD patients inducibly express colonic chitinase 3-like 1 (CHI3L1) that is further upregulated during CAC development. However, little is known about the direct pathogenic involvement of CHI3L1 in vivo. Here we demonstrate that CHI3L1 (aka Brp39) knockout (KO) mice treated with azoxymethane (AOM)/dextran sulphate sodium (DSS) developed severe colitis but lesser incidence of CAC as compared to that in wild-type (WT) mice. Highest CHI3L1 expression was found during the chronic phase of colitis, rather than the acute phase, and is essential to promote intestinal epithelial cell (IEC) proliferation in vivo. This CHI3L1-mediated cell proliferation/survival involves partial downregulation of the pro-apoptotic S100A9 protein that is highly expressed during the acute phase of colitis, by binding to the S100A9 receptor, RAGE (Receptor for Advanced Glycation End products). This interaction disrupts the S100A9-associated expression positive feedback loop during early immune activation, creating a CHI3L1^hi S100A9^low colonic environment, especially in the later phase of colitis, which promotes cell proliferation/survival of both normal IECs and tumor cells.

Faecal chitinase 3-like 1 is a reliable marker as accurate as faecal calprotectin in detecting endoscopic activity in adult patients with inflammatory bowel diseases

BACKGROUND

Faecal biomarkers are emerging tools in the assessment of mucosal healing in inflammatory bowel diseases (IBDs).

AIM

To evaluate the accuracy of faecal chitinase 3-like 1(CHI3L1) compared to calprotectin in detecting endoscopic activity in IBD.

METHODS

Overall, 86 IBD adults underwent colonoscopy consecutively and prospectively, with Crohn's disease Endoscopic Index of Severity (CDEIS) or Mayo endoscopic subscore calculation for ulcerative colitis, and stool collection. Faecal calprotectin was measured using quantitative immunochromatographic testing. Faecal CHI3L1 was quantified by ELISA. CHI3L1 cut-off value was determined using a receiver-operating curve.

RESULTS

In 54 Crohn's disease patients, faecal CHI3L1 (ρ = 0.70, P < 0.001) and calprotectin (ρ = 0.74, P < 0.001) levels correlated with CDEIS and were significantly increased in patients with endoscopic ulceration. In patients with ileal Crohn's disease, faecal CHI3L1 seemed to be better correlated with CDEIS than faecal calprotectin (ρ = 0.78 vs. ρ = 0.62, P < 0.001 for both). CHI3L1 > 15 ng/g detected endoscopic ulceration in Crohn's disease with a sensitivity of 100% and a specificity of 63.6%, compared to faecal calprotectin > 250 μg/g showing a sensitivity of 90.5% and a specificity of 59.1%. In 32 ulcerative colitis patients, faecal CHI3L1 and calprotectin levels correlated with Mayo endoscopic subscore (ρ = 0.44 and 0.61, respectively, P < 0.001 for both) and were significantly increased in ulcerative colitis patients with endoscopic activity. In ulcerative colitis patients, faecal CHI3L1 > 15 ng/g predicted endoscopic activity with a sensitivity of 81.8% and a specificity of 80.0%, compared to faecal calprotectin>250 μg/g showing a sensitivity of 86.4% and a specificity of 80.0%.

CONCLUSION

Faecal CHI3L1 is a reliable biomarker in detecting endoscopic activity in IBD.

Implementation of the simple endoscopic activity score in crohn's disease

Simple Endoscopic Score for Crohn's Disease (SES-CD) was developed as an attempt to simplify Crohn's Disease Endoscopic Index of Severity (CDEIS). Since it was constructed from CDEIS, SES-CD performs comparably but also carries similar limitations. Several studies have utilized SES-CD scoring to describe disease severity or response to therapy. Some of them used SES-CD score as a continuous variable while others utilized certain cutoff values to define severity grades. All SES-CD cutoff values reported in published clinical trials were empirically selected by experts. Although in most of the studies that used SEC-CD scoring to define disease severity, a score <3 reflected inactive disease, no study is using score 0 to predefine inactivity. Studies applying SES-CD to define response to treatment used score 0. There is no optimal SES-CD cut-off for endoscopic remission. The quantification of mucosal healing using SES-CD scoring has not been standardized yet. As the definition of mucosal healing by SES-CD is unset, the concept of deep remission is also still evolving. Serum and fecal biomarkers as well as new radiologic imaging techniques are complementary to SES-CD. Current practice as well as important changes in endoscopy should be taken into consideration when defining SES-CD cutoffs. The optimal timing of SES-CD scoring to assess mucosal healing is not defined yet. To conclude, SES-CD represents a valuable tool. However, a consensus agreement on its optimal use is required.

Biomarkers of Inflammation in Inflammatory Bowel Disease

Recent observations suggest that subjective measures of disease activity in inflammatory bowel disease (IBD) are often misleading. Objective measures of inflammation are more closely associated with important long-term outcomes, but often depend upon invasive and costly procedures such as ileocolonoscopy and cross-sectional imaging by computed tomography or magnetic resonance imaging. Noninvasive, accurate, and inexpensive measures of intestinal inflammation would allow clinicians to adopt widely the paradigm of adjusting therapies with a goal of controlling inflammation. Blood, stool, and urine markers have all been explored as indicators of intestinal inflammation in IBD, and although none has been universally adopted, some have been well-characterized, and others hold great promise. Serum C-reactive protein and fecal calprotectin are among the best-studied noninvasive biomarkers of inflammation in IBD, and their test characteristics have been described in the setting of differentiating IBD from irritable bowel syndrome, for grading inflammation, to describe the response to therapy, and in demonstrating recurrent inflammation after medical or surgically induced remission. High-throughput research platforms, including gene expression arrays, metabolomics and proteomics, are also being applied to the discovery of novel biomarkers of inflammation. It is certain that biomarkers of inflammation will attain growing importance in the clinic as we strive for more effective and cost-effective strategies to treat patients with IBD.

Application of Comparative Transcriptional Genomics to Identify Molecular Targets for Pediatric IBD

Experimental models of colitis in mice have been used extensively for analyzing the molecular events that occur during inflammatory bowel disease (IBD) development. However, it is uncertain to what extent the experimental models reproduce features of human IBD. This is largely due to the lack of precise methods for direct and comprehensive comparison of mouse and human inflamed colon tissue at the molecular level. Here, we use global gene expression patterns of two sets of pediatric IBD and two mouse models of colitis to obtain a direct comparison of the genome signatures of mouse and human IBD. By comparing the two sets of pediatric IBD microarray data, we found 83 genes were differentially expressed in a similar manner between pediatric Crohn’s disease and ulcerative colitis. Up-regulation of the chemokine (C–C motif) ligand 2 (CCL2) gene that maps to 17q12, a confirmed IBD susceptibility loci, indicates that our comparison study can reveal known genetic associations with IBD. In comparing pediatric IBD and experimental colitis microarray data, we found common signatures amongst them including: (1) up-regulation of CXCL9 and S100A8; (2) cytokine–cytokine receptor pathway dysregulation; and (3) over-represented IRF1 and IRF2 transcription binding sites in the promoter region of up-regulated genes, and HNF1A and Lhx3 binding sites were over-represented in the promoter region of the down-regulated genes. In summary, this study provides a comprehensive view of transcriptome changes between different pediatric IBD populations in comparison with different colitis models. These findings reveal several new molecular targets for further study in the regulation of colitis.

Usefulness of a novel and rapid assay system for fecal calprotectin in pediatric patients with inflammatory bowel diseases

BACKGROUND AND AIM

Fecal calprotectin (FC) has become a reliable biomarker for intestinal inflammation in inflammatory bowel diseases (IBDs). However, a simple and rapid assay to replace conventional ELISA is necessary for wider use in clinical practice. In this study, we investigated the usefulness of a novel method for measuring FC using a colloidal gold aggregation (CGA) assay for assessing mucosal inflammation in pediatric IBDs.

METHODS

FC levels were determined by ELISA and CGA assay in 309 fecal samples (ulcerative colitis [UC]: 131; Crohn's disease [CD]: 121; healthy controls: 57). For endoscopic evaluation, the modified Matts' grading system for UC and the simple endoscopic score for CD were used.

RESULTS

A strong correlation was found between the FC values determined by the two methods (r = 0.98, P < 0.01). FC levels, determined by CGA assay, strongly correlated with the endoscopic score for UC (r = 0.70, P < 0.01) and CD (r = 0.58, P < 0.01). In the UC patients with endoscopic remission, the FC levels determined by CGA assay (median: 31.5 μg/g, n = 14) were as low as in healthy controls. For patients in clinical remission but showing an active status endoscopically, FC was more likely to be abnormal than commonly used laboratory markers.

CONCLUSIONS

Our simple and rapid assay system has excellent performance for assessing mucosal inflammation of IBDs and can be replaced for ELISA. Practical application of this assay system enables us to use FC measurement more widely in clinical practice.

Biomarkers of inflammatory bowel disease

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

From bacteria to human: a journey into the world of chitinases

Chitinases, the enzymes responsible for the biological degradation of chitin, are found in a wide range of organisms from bacteria to higher plants and animals. They participate in numerous physiological processes such as nutrition, parasitism, morphogenesis and immunity. Many organisms, in addition to chitinases, produce inactive chitinase-like lectins that despite lacking enzymatic activity are involved in several regulatory functions. Most known chitinases belong to families 18 and 19 of glycosyl hydrolases, however a few chitinases that belong to families 23 and 48 have also been identified in recent years. In this review, different aspects of chitinases and chi-lectins from bacteria, fungi, insects, plants and mammals are discussed.

Multicenter analysis of fecal microbiota profiles in Japanese patients with Crohn's disease

BACKGROUND

We analyzed the fecal microbiota profiles of patients with Crohn's disease (CD) at 4 inflammatory bowel disease (IBD) centers located in different districts in Japan.

METHODS

Terminal restriction fragment length polymorphism (T-RFLP) analysis was performed in 161 fecal samples from CD patients and 121 samples from healthy individuals. The bacterial diversity was evaluated by the Shannon diversity index (SDI).

RESULTS

There were no regional differences in the fecal microbiota profiles of the healthy individuals in Japan. A setting of similarity generated three major clusters of T-RFs: one included almost all the healthy individuals (118/121), and the other two clusters were mainly formed by CD patients at different stages of disease activity. The changes in simulated bacterial composition indicated that the class Clostridia, including the genus Faecalibacterium, was significantly decreased in CD patients with active disease and those in remission as compared with findings in the healthy individuals. In contrast, the genus Bacteroides was significantly increased in CD patients during the active phase as compared with findings in the healthy individuals. The genus Bifidobacterium was significantly decreased during the active phase of CD and increased to healthy levels during the remission phase. The bacterial diversity measured by the SDI was significantly reduced in CD patients during the active and remission phases as compared with findings in the healthy individuals. From the clinical data and T-RFLP analysis, we developed a logistic model to predict disease activity based on the fecal microbiota composition.

CONCLUSION

Dysbiosis in CD patients was shown by a multi-IBD center study. The feasibility of using the fecal microbiota profile as a predictive marker for disease activity is proposed.