Guangxi Zhou

ASCA, ANCA, ALCA and Many More: Are They Useful in the Diagnosis of Inflammatory Bowel Disease?

Background: Inflammatory bowel disease (IBD) is characterized by excessive immune responses to altered intestinal microbiota in genetically susceptible individuals. The diagnosis of IBD depends on clinical, endoscopic, histological, radiological and biochemical criteria, which may be invasive, time consuming and usually not accepted by patients with IBD. Key Messages: Serological biomarkers have been demonstrated to be a series of rapid, non-invasive approaches for assessments of early diagnosis, disease activity and prognosis for IBD. Importantly, serum antibodies against microbial antigens or auto-antigens have been used as biomarkers in predicting disease course, complications and responses to medications and surgery. Moreover, they have been demonstrated to be useful in distinguishing patients with Crohns disease (CD) from those with ulcerative colitis (UC). Recently, a great number of new serum biomarkers (e.g., anti-glycoprotein 2, anti-granulocyte macrophage colony-stimulating factor, anti-neutrophil cytoplasmic antibody, anti-Saccharomyces cerevisiae antibody, anti-laminaribioside carbohydrate IgG antibody, anti-mannobioside carbohydrate IgG antibody, antibody to the outer membrane protein of Escherichia coli, anti-CBir1) have been found to be present in patients with IBD and are potentially used in the diagnosis and prediction. The presence of these antibodies in the sera is due to the disruption of intestinal mucosa barrier and they may reflect a possibly genetic loss of immunological tolerance toward microbiota-derived antigens. Due to their non-invasive, easily accessible, repetitive and economical characteristics, these biomarkers have been found to serve as precious supplementary means in the diagnosis and disease evaluation of IBD. Conclusions: Currently, the most important utility of serological biomarkers is to evaluate the aggressive risks of disease phenotype, complications or surgery requirement, predict prognosis of the disease and distinguish CD from UC. However, they have limited values in making initially definite diagnosis for IBD. Therefore, more effective biomarkers with high sensitivity and specificity need to be further explored in the future.

CD177+ neutrophils as functionally activated neutrophils negatively regulate IBD

Background Neutrophils are accumulated in inflamed mucosa of IBD and play an important role in the pathogenesis. CD177 is expressed in neutrophils specifically and upregulated during inflammation. However, the role of CD177+ neutrophils in pathogenesis of IBD remains elusive. Materials and methods Expression of CD177 was analysed in peripheral blood and intestinal mucosa from patients with IBD using quantitative RT-PCR, flow cytometry and immunohistochemistry. CD177+ and CD177− neutrophils were isolated to determine gene differences by RNA sequencing. Colitis was established in CD177−/− and wild-type mice in response to dextran sulfate sodium (DSS) insults to determine the role of CD177+ neutrophils in IBD. Results CD177+ neutrophils were markedly increased in peripheral blood and inflamed mucosa from patients with active IBD compared with healthy controls. RNA sequencing revealed that differential gene expression between CD177+ and CD177− neutrophils from patients with IBD was associated with response to bacterial defence, hydrogen peroxide and reactive oxygen species (ROS). CD177+ neutrophils produced lower levels of proinflammatory cytokines (ie, interferon-γ, interleukin (IL)-6, IL-17A), but higher levels of IL-22 and transforming growth factor-β, and exhibited increased bactericidal activities (ie, ROS, antimicrobial peptides, neutrophil extracellular trap) compared with CD177− subset. CD177−/− mice developed more severe colitis on DSS insults compared with wild-type mice. Moreover, CD177 deficiency led to compromised intestinal barrier and impaired antibacterial immunity through decreased production of IL-22 by CD177− neutrophils. Conclusions CD177+ neutrophils represent functionally activated population and play a protective role in IBD through increased bactericidal activity and IL-22 production. Targeting CD177+ neutrophils may be beneficial for treatment of IBD.

Serum Levels of Lipopolysaccharide and 1,3-β-D-Glucan Refer to the Severity in Patients with Crohn’s Disease

Objectives. Interactions between the host and gut microbial community contribute to the pathogenesis of Crohns disease (CD). In this study, we aimed to detect lipopolysaccharide (LPS) and 1,3-β-D-glucan (BG) in the sera of CD patients and clarify the potential role in the diagnosis and therapeutic approaches. Materials and Methods. Serum samples were collected from 46 patients with active CD (A-CD), 22 CD patients at remission stage (R-CD), and 20 healthy controls, and the levels of LPS, BG, and TNF in sera were determined by ELISA. Moreover, sixteen patients with A-CD received anti-TNF monoclonal antibody therapy (infliximab, IFX) at a dose of 5 mg/kg body weight at weeks 0, 2, and 6, and the levels of LPS and BG were also tested at week 12 after the first intravenous infusion. Results. Serum levels of LPS and BG were found to be markedly increased in A-CD patients compared with R-CD patients and healthy controls (P < 0.05). They were also observed to be positively correlated with CDAI, ESR, and SES-CD, respectively (P < 0.05). Furthermore, the levels of TNF in sera had a significant correlation with LPS and BG, respectively. The concentrations of LPS and BG were demonstrated to be significantly downregulated in the sera of A-CD patients 12 weeks after IFX treatment (P < 0.05), suggesting that blockade of TNF could inhibit bacterial endotoxin absorption, partially through improving intestinal mucosal barrier. Conclusions. Serum levels of LPS and BG are significantly increased in A-CD patients and positively correlated with the severity of the disease. Blockade of intestinal mucosal inflammation with IFX could reduce the levels of LPS and BG in sera. Therefore, this study has shed some light on measurement of serum LPS and BG in the diagnosis and treatment of CD patients.

Hypoxia inducible factor-1α-induced interleukin-33 expression in intestinal epithelia contributes to mucosal homeostasis in inflammatory bowel disease

Intestinal epithelial cells (IECs), an important barrier to gut microbiota, are subject to low oxygen tension, particularly during intestinal inflammation. Hypoxia inducible factor‐1α (HIF‐1α) is expressed highly in the inflamed mucosa of inflammatory bowel disease (IBD) and functions as a key regulator in maintenance of intestinal homeostasis. However, how IEC‐derived HIF‐1α regulates intestinal immune responses in IBD is still not understood completely. We report here that the expression of HIF‐1α and IL‐33 was increased significantly in the inflamed mucosa of IBD patients as well as mice with colitis induced by dextran sulphate sodium (DSS). The levels of interleukin (IL)−33 were correlated positively with that of HIF‐1α. A HIF‐1α‐interacting element was identified in the promoter region of IL‐33, indicating that HIF‐1α activity regulates IL‐33 expression. Furthermore, tumour necrosis factor (TNF) facilitated the HIF‐1α‐dependent IL‐33 expression in IEC. Our data thus demonstrate that HIF‐1α‐dependent IL‐33 in IEC functions as a regulatory cytokine in inflamed mucosa of IBD, thereby regulating the intestinal inflammation and maintaining mucosal homeostasis.

Hypoxia inducible factor-1α-induced IL-33expression in intestinal epithelia contributes to mucosal homeostasis ininflammatory bowel disease

Intestinal epithelial cells (IECs), an important barrier to gut microbiota, are subject to low oxygen tension, particularly during intestinal inflammation. Hypoxia inducible factor‐1α (HIF‐1α) is expressed highly in the inflamed mucosa of inflammatory bowel disease (IBD) and functions as a key regulator in maintenance of intestinal homeostasis. However, how IEC‐derived HIF‐1α regulates intestinal immune responses in IBD is still not understood completely. We report here that the expression of HIF‐1α and IL‐33 was increased significantly in the inflamed mucosa of IBD patients as well as mice with colitis induced by dextran sulphate sodium (DSS). The levels of interleukin (IL)−33 were correlated positively with that of HIF‐1α. A HIF‐1α‐interacting element was identified in the promoter region of IL‐33, indicating that HIF‐1α activity regulates IL‐33 expression. Furthermore, tumour necrosis factor (TNF) facilitated the HIF‐1α‐dependent IL‐33 expression in IEC. Our data thus demonstrate that HIF‐1α‐dependent IL‐33 in IEC functions as a regulatory cytokine in inflamed mucosa of IBD, thereby regulating the intestinal inflammation and maintaining mucosal homeostasis.

Blockade of PLD2 Ameliorates Intestinal Mucosal Inflammation of Inflammatory Bowel Disease

Background. Inflammatory bowel diseases (IBD), including Crohns disease (CD) and ulcerative colitis (UC), are chronically remittent and progressive inflammatory disorders. Phospholipase D2 (PLD2) is reported to be involved in the pathogenesis of several inflammatory diseases. However, the exact role of PLD2 in IBD is obscure. Methods. PLD2 expression was determined in peripheral blood cells and inflamed mucosa from patients with IBD by qRT-PCR. Colonic biopsies were also obtained from CD patients before and after infliximab (IFX) treatment to examine PLD2 expression. PLD2 selective inhibitor (CAY10594) was administrated daily by oral gavage in DSS-induced colitis mice. Bone marrow neutrophils from colitis mice were harvested to examine the migration using Transwell plate. Results. PLD2 was found to be significantly increased in peripheral blood cells and inflamed mucosa in patients with active IBD. Treatment with IFX could significantly decrease PLD2 expression in intestinal mucosa in patients with CD. Moreover, blockade of PLD2 with CAY10594 could markedly ameliorate DSS-induced colitis in mice and promote neutrophil migration. Conclusions. PLD2 plays a critical role in the pathogenesis of IBD. Blockade of PLD2 may serve as a new therapeutic approach for treatment of IBD.

CD177+ neutrophils suppress epithelial cell tumourigenesis in colitis-associated cancer and predict good prognosis in colorectal cancer

Neutrophils are found to be infiltrated in tumour tissues of patients with colitis-associated cancer (CAC) and colorectal cancer (CRC), and CD177 is mainly expressed in neutrophils. In our study, expression of CD177 in tumour tissues from patients with CAC or CRC was analysed byquantitative real-time polymerase chain reaction, flow cytometry and immunohistochemistry. We recruited 378 patients with CRC, determined CD177 expression in tumours and examined its correlation with clinicopathological features. Moreover, CAC model was induced in wild-type and CD177-/- mice by azoxymethane/dextran sodium sulphate. CD177+ neutrophils were significantly increased in colon tumour tissues from patients with CRC or CAC compared with controls. Expression of CD177 mRNA and percentages of CD177+ neutrophils were also markedly increased in tumour tissues from CRC patients compared with controls. Patients with high density of CD177+ neutrophils had better overall survival and disease-free survival compared with controls. Multivariate analyses revealed that the density of CD177+ neutrophils was an independent factor in predicting overall survival and disease-free survival. Consistently, CD177 depletion aggravated azoxymethane/dextran sodium sulphate-induced CAC in mice. Expression of Ki67 and proliferating cell nuclear antigen was increased in tumour tissues from CD177-/- mice compared with wild-type counterparts. Moreover, CD177-/- neutrophils failed to migrate in response to fMLP[AU: Please expand fMLP, DN, TNM and HIF-1α.] stimulation compared with wild-type controls. Our data indicate that CD177+ neutrophils suppress epithelial cell tumourigenesis and act as an independent factor in predicting the prognosis in patients with CRC. CD177+ neutrophils may serve as a novel therapeutic target in the treatment and predict the prognosis of CAC and CRC.

Food-specific IgGs Are Highly Increased in the Sera of Patients with Inflammatory Bowel Disease and Are Clinically Relevant to the Pathogenesis

Objective Dietary antigens are common luminal antigens in the gastrointestinal tract and have been considered to contribute to the pathogenesis of inflammatory bowel disease (IBD). We analyzed the levels of food-specific IgGs against a variety of dietary antigens, explored the clinical relevance of food allergy to the pathogenesis of IBD, and investigated whether or not infliximab (IFX) treatment could regulate the immune responses induced by dietary antigens. Methods A total of 301 IBD patients, including 201 patients with Crohns disease (CD) and 100 patients with ulcerative colitis (UC), were recruited, and their serum food-specific IgGs against 14 food antigens were detected by a semi-quantitative enzyme linked immunosorbent assay (ELISA). Total serum IgG and IgE levels were measured by immunonephelometry and fluorescent enzyme immunoassay, respectively. Simultaneously, the relevant medical records and clinical data were collected for further analyses. Results Food-specific IgGs against egg, milk, wheat, corn, rice, tomato, codfish, and soybean antigens were found to be significantly increased in the sera of CD patients compared with UC patients and healthy controls (p<0.01). The levels of total serum IgG and IgE were also significantly higher in CD patients than in healthy controls (p<0.01). The titers of corn- and tomato-specific IgGs were found to be significantly correlated with total serum IgG in CD patients (p<0.05), while the titers of egg-, milk-, and wheat-specific IgGs were correlated with total serum IgE (p<0.05). Interestingly, IFX therapy was able to down-regulate the food-specific IgG-mediated immune response markedly in active CD patients. Conclusion Food-specific IgGs against egg, milk, wheat, corn, rice, tomato, codfish, and soybean are highly increased in the sera of CD patients. IFX treatment was able to down-regulate the levels of food-specific IgGs by suppressing intestinal inflammation and promoting mucosal healing. Therefore, food-specific IgGs may serve as an important approach in the diagnosis and management of food allergy in IBD.

Tripartite motif-containing (TRIM) 21 negatively regulates intestinal mucosal inflammation through inhibiting TH1/TH17 cell differentiation in patients with inflammatory bowel diseases

Background Tripartite motif‐containing (TRIM) 21 has been implicated in the pathogenesis of several types of autoimmune diseases. Objective We sought to elucidate TRIM21 expression in patients with inflammatory bowel diseases (IBDs) and its role in regulating intestinal mucosal inflammation. Methods TRIM21 expression was analyzed in the inflamed mucosa of patients with IBDs by means of quantitative RT‐PCR and immunohistochemistry. Peripheral blood CD4+ T cells were transfected with lentivirus‐expressing TRIM21 (LV‐TRIM21) or LV‐sh‐TRIM21, and cytokine expression was determined by using quantitative RT‐PCR and ELISA. TRIM21−/− mice were generated, and trinitrobenzene sulfonic acid– and CD45RBhighCD4+ T cell–induced colitis models were established to determine its role in induction of intestinal inflammation. Results TRIM21 was expressed predominantly in CD4+ T cells and decreased markedly in the inflamed mucosa of patients with IBDs compared with healthy control subjects. Ectopic expression of TRIM21 inhibited IBD CD4+ T cells to differentiate into TH1 and TH17 cells, whereas downregulation of TRIM21 had the opposite effects. TRIM21−/− mice had more severe colitis after administration of trinitrobenzene sulfonic acid compared with wild‐type mice, which was characterized by increased expression of IFN‐&ggr;, TNF‐&agr;, and IL‐17A in the colon. TRIM21−/−CD45RBhighCD4+ T cells reconstituted into recombination‐activating gene (Rag1)−/− mice induced more severe colitis than in wild‐type control mice. Mechanistically, interferon regulatory factor 3 was identified as a functional downstream target of TRIM21 in that silencing of interferon regulatory factor 3 suppressed TRIM21−/−CD4+ T‐cell differentiation into TH1 and TH17 cells. Conclusions TRIM21 plays a protective role in mucosal inflammation through inhibiting TH1 and TH17 cell differentiation. Thus TRIM21 might serve as a potential therapeutic target for the treatment of IBDs.