Candidate mucosal and surrogate biomarkers of inflammatory bowel disease in the era of new technology

Skin damage caused by scale loss modifies the intestine of chronically stressed gilthead sea bream (Sparus aurata, L.)

The present study was designed to test if the damage caused by scale loss provokes a change in other innate immune barriers such as the intestine and how chronic stress affects this response. Sea bream (Sparus aurata) were kept in tanks at low density (16 kg m^-3, LD) or exposed to a chronic high density (45 kg m^-3, HD) stress for 4 weeks. Scales were then removed (approximately 50%) from the left flank in the LD and HD fish. Intestine samples (n = 8/group) were examined before and at 12 h, 3 days and 7 days after scale removal. Changes in the morphology of the intestine revealed that chronic stress and scale loss was associated with intestinal inflammation. Specifically, enterocyte height and the width of the lamina propria, submucosa and muscle layer were significantly increased (p < 0.05) 3 days after skin damage in fish under chronic stress (HD) compared to other treatments (LDWgut3d or HDgut0h). This was associated with a significant up-regulation (p < 0.05) in the intestine of gene transcripts for cell proliferation (pcna) and anti-inflammatory cytokine tgfβ1 and down-regulation of gene transcripts for the pro-inflammatory cytokines tnf-α and il1β (p < 0.05) in HD and LD fish 3 days after scale removal compared to the undamaged control (LDgut0h). Furthermore, a significant up-regulation of kit, a marker of mast cells, in the intestine of HDWgut3d and LDWgut3d fish suggests they may mediate the crosstalk between immune barriers. Skin damage induced an increase in cortisol levels in the anterior intestine in HDWgut12 h fish and significant (p < 0.05) down-regulation of mr expression, irrespective of stress. These results suggest glucocorticoid levels and signalling in the intestine of fish are modified by superficial cutaneous wounds and it likely modulates intestine inflammation.

Intestinal inflammatory profile shows increase in a diversity of biomarkers in irritable bowel syndrome

Background: It has been proposed that irritable bowel syndrome (IBS) is a low-grade mucosal inflammatory disease.Objective: To characterize the intestinal inflammatory profile in IBS patients with or without fructose intolerance.Design: Patients referred to colonoscopy with IBS complaints were screened for participation. IBS patients diagnosed according to the Rome II criteria and with no organic gastrointestinal disease were included in the study. One subgroup was patients included in a fructose-reduced diet study for 2 months with effects based on VAS symptom scores. Healthy controls were subjects under investigation of colorectal cancer screening with no IBS or other gastrointestinal diseases. All patients included had normal histology from rectum. Mucosal cytokines, chemokines and growth factors were measured by multiplex technology.Results: Of 27 inflammatory markers tested in the mucosal tissue, 13 were significantly increased and none was significantly decreased in IBS as compared to controls. Significantly increased were the proinflammatory cytokines tumor necrosis factor, the typical TH1 markers IFNγ, IL-1β, IL-2 and RANTES, the typical TH2 markers IL-5 and IL-9, the TH17 marker IL-17, TNF, the pleiotropic IL-15, and the growth factors bFGF and GM-CSF. In IBS patients with fructose intolerance only IL-5 was significantly increased compared to patients without fructose intolerance.Conclusions: A dysregulated mucosal inflammatory profile with an increased level of TH1, TH2 and TH17 markers, and growth factors were observed in bowel mucosa in of IBS patients when compared to healthy controls.

Preclinical evaluation of EPHX2 inhibition as a novel treatment for inflammatory bowel disease

Epoxyeicosatrienoic acids (EETs) are signaling lipids produced by cytochrome P450 epoxygenation of arachidonic acid, which are metabolized by EPHX2 (epoxide hydrolase 2, alias soluble epoxide hydrolase or sEH). EETs have pleiotropic effects, including anti-inflammatory activity. Using a Connectivity Map (CMAP) approach, we identified an inverse-correlation between an exemplar EPHX2 inhibitor (EPHX2i) compound response and an inflammatory bowel disease patient-derived signature. To validate the gene-disease link, we tested a pre-clinical tool EPHX2i (GSK1910364) in a mouse disease model, where it showed improved outcomes comparable to or better than the positive control Cyclosporin A. Up-regulation of cytoprotective genes and down-regulation of proinflammatory cytokine production were observed in colon samples obtained from EPHX2i-treated mice. Follow-up immunohistochemistry analysis verified the presence of EPHX2 protein in infiltrated immune cells from Crohn's patient tissue biopsies. We further demonstrated that GSK2256294, a clinical EPHX2i, reduced the production of IL2, IL12p70, IL10 and TNFα in both ulcerative colitis and Crohn's disease patient-derived explant cultures. Interestingly, GSK2256294 reduced IL4 and IFNγ in ulcerative colitis, and IL1β in Crohn's disease specifically, suggesting potential differential effects of GSK2256294 in these two diseases. Taken together, these findings suggest a novel therapeutic use of EPHX2 inhibition for IBD.

Increased IL-17A/IL-17F expression ratio represents the key mucosal T helper/regulatory cell-related gene signature paralleling disease activity in ulcerative colitis

BACKGROUND

T helper (T_h) and regulatory T (T_reg) cell-related cytokines are implicated in inflammatory bowel diseases, including ulcerative colitis (UC). While these cytokines are generally upregulated in inflamed mucosae, the key cytokine profile explaining disease severity has not been determined.

METHODS

The Rachmilewitz endoscopic index (REI) was assessed in 61 UC patients undergoing colonoscopy. Biopsies obtained from inflamed (REI 3-12) and noninflamed (REI 0-2) areas were analyzed by quantitative PCR for expression of mRNAs encoding cytokines and transcription factors related to Th1 (TNF-α, IFN-γ, IL-12p35, IL-12p40, and T-bet), Th2 (IL-4, IL-13, IL-33, and GATA3), Th17 (IL-17A, IL-17F, IL-21, IL-22, IL-23p19, IL-6, and RORC), Th9 (IL-9, IRF4, and PU.1), and Treg (TGF-β and Foxp3). Expression patterns associated with higher REI were determined by univariate and multivariate analyses.

RESULTS

Despite general upregulation, none of these mRNAs showed univariate correlation with REI in inflamed samples. Multiple regression analysis, however, found that joint expression of IL-17A, IL-17F, IL-21, RORC, and TGF-β was significantly predictive of REI (P < 0.0002, R² = 0.380), with major individual contributions by IL-17A (P < 0.0001) and IL-17F (P < 0.0001), which were associated with increased and decreased REI, respectively. Partial correlation analysis, validating this model, indicated differences between IL-17A and IL-17F in correlating with other targets. The IL-17A/IL-17F ratio showed a significant correlation with REI (r = 0.5124, P < 0.0001), whereas no other mRNAs were essentially predictive of REI.

CONCLUSIONS

Mucosal IL-17A/IL-17F ratio significantly correlates with endoscopic score in UC patients, accompanied by their disparate interactions with other T_h/T_reg-related genes.

Alterations in cytokine gene expression profile in colon mucosa of Inflammatory Bowel Disease patients on different therapeutic regimens

Inflammatory bowel disease (IBD) is assumed to be caused by genetic and environmental factors that interact together in promoting intestinal immune dysregulation where cytokines have validated role. However, the underlying intimate mechanisms in the human IBD involving cytokines still needs to be supplemented especially in the clinical context. The aim of this study was to investigate the expression of some inflammatory and regulatory cytokines (IL-17A, IL-23, IL-6, TGFβ1, and IL-10) as well as of the transcription factor FoxP3 in mucosal samples of IBD and non-IBD patients. We assessed the mRNA relative quantities (RQ) of the above-mentioned cytokines and the transcription factor FoxP3 in paired colonic samples (inflamed and adjacent normal mucosa) from 37 patients with IBD and in normal mucosal tissue in 12 persons without IBD by performing a qRT-PCR assay and tested the protein levels of target cytokines in serum samples. The patients were divided into three groups: without any therapy (n=10), on 5-ASA (n=11) and on immunosuppressants (Azathioprine±5-ASA/corticosteroids) (n=16) in order to compare the RQ values for each therapeutic group. All investigated genes were found upregulated in the inflamed mucosa of IBD patients in the following order: IL-6>FoxP3>TGFβ1>IL-23>IL-17A>IL-10. We also observed that the gene expression of FoxP3 and IL-6 were substantially higher in the inflamed mucosal tissue of the IBD patients than the adjacent normal mucosa (p=0.035, p=0.03 respectively). Differences between higher mRNA expression of FoxP3 and IL-6 in inflamed tissue were considered significant in patients with ulcerative colitis (UC) (p=0.011, p=0.000 respectively) and with Crohn's disease (CD) (p=0.008, p=0.000 respectively) in comparison to the normal mucosa of non-IBD persons and we found increased TGFβ1 in CD patients alone (p=0.041). Furthermore, IL-6 and TGFβ1 were overexpressed (RQ>10) in non-inflamed mucosa from IBD patients compared to the normal mucosa from the controls. When we compared the gene expression for paired mucosa in the immunosuppressive treated group with the 5-ASA treated group we observed opposite changes in IL-6 and TGFβ1 expression. Additionally, we found higher serum levels of IL-23 (p=0.008), TGFβ1 and IL-6 in IBD patients compared to non-IBD patients. The obtained specific expression profile consisting of IL-6, TGFβ1, IL-10 and FoxP3 may represent a transcriptional hallmark for IBD. Furthermore, we found that treatment with immunosuppressive therapy was more beneficial for driving cytokine expression to restore immune regulation in patients with IBD, unlike the 5-ASA therapy.

Mucosal healing in inflammatory bowel disease: Maintain or de-escalate therapy

In the past decade, thanks to the introduction of biologic therapies, a new therapeutic goal, mucosal healing (MH), has been introduced. MH is the expression of an arrest of disease progression, resulting in minor hospitalizations, surgeries, and prolonged clinical remission. MH may be achieved with several therapeutic strategies reaching success rates up to 80% for both, ulcerative colitis (UC) and Crohn’s disease (CD). Various scoring systems for UC and for the transmural CD, have been proposed to standardize the definition of MH. Several attempts have been undertaken to de-escalate therapy once MH is achieved, thus, reducing the risk of adverse events. In this review, we analysed the available studies regarding the achievement of MH and the subsequent treatment de-escalation according to disease type and administered therapy, together with non-invasive markers proposed as predictors for relapse. The available data are not encouraging since de-escalation after the achievement of MH is followed by a high number of clinical relapses reaching up to 50% within one year. Unclear is also another question, in case of combination therapies, which drug is more appropriate to stop, in order to guarantee a durable remission. Predictors of unfavourable outcome such as disease extension, perianal disease, or early onset disease appear to be inadequate to foresee behaviour of disease. Further studies are warranted to investigate the role of histologic healing for the further course of disease.

Normalization of mucosal tumor necrosis factor-α: A new criterion for discontinuing infliximab therapy in ulcerative colitis

BACKGROUND

Biological agents such as anti-tumor necrosis factor (TNF) induce remission in ulcerative colitis. There is however no consensus regarding the discontinuation of this treatment.

AIM

The aim of this study is to assess whether clinical parameters and mucosal cytokine mRNAs in healed colonic mucosa can predict long-term remission in ulcerative colitis following discontinuation of infliximab (IFX) therapy.

METHODS

The prospective Tromsø Inflammatory Bowel Disease (IBD) Study is based on an intensified induction treatment algorithm with IFX to achieve disease remission. Following clinical and endoscopic remission, IFX treatment was discontinued, and follow-up until relapse was performed. Patients who achieved clinical and endoscopic remission following an induction course of IFX were included. Expression levels of TNF alpha (TNF), interferon gamma (IFNG), interleukin (IL) 6 (IL6), IL17A, IL23, and transforming growth factor beta (TGFB) were quantified by real-time PCR in mucosal biopsies obtained at colonoscopy. Remission was defined as Ulcerative Colitis Disease Activity Index (UCDAI) below 3, and an endoscopic sub-score of 0-1. Relapse was defined as UCDAI score >3 and endoscopic sub-score >1. Mucosal cytokine transcript levels from 20 non-IBD patients with a normal colonoscopy served as control group.

RESULTS

Of the 45 patients included, twenty patients (44%) had normalized levels of mucosal TNF expression at the time of mucosal healing, whereas 35 of 42 (83%) had normalized IL17A expression levels, and 31 of 36 (86%) had normalized IFNG expression levels. The median time to relapse was 8months (range 4-12). Normalization of TNF gene expression predicted 20months (1-39) relapse-free survival after withdrawal of IFX compared to 5months (3-7) in the group with elevated TNF expression. Mucosal expression levels of IL17A, IL23, IFNG, TGFB, IL6 did not predict long-term remission (>12months)

CONCLUSION

Normalization of mucosal TNF predicts long-term remission after discontinuation of IFX.

Heat shock factor 2 levels are associated with the severity of ulcerative colitis

BACKGROUND AND AIMS

The morbidity of ulcerative colitis (UC) is increasing in China every year. In addition, there is a lack of accurate diagnostic indices with which to evaluate the activity of the disease. The aim of this study was to identify UC-associated proteins as biomarkers for the diagnosis, and objective assessment of disease activity.

METHODS

Differential expression of serum proteins from UC patients compared to normal controls was analyzed by two-dimensional electrophoresis (2-DE) and matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF-MS). The expression of heat shock factor 2(HSF2)in colonic mucosa in Crohn's disease, Behcet's disease, ulcerative colitis, intestinal tuberculosis, infective enteritis, intestinal lymphoma, and normal controls was investigated by immunohistochemistry (IHC). The expression of the HSF2 in colonic mucosa of UC subjects with varying severity of disease was measured by real time-PCR and Western Blots. The expression of HSF2 was inhibited by HSF2 small interfering RNA (siRNA) transfection in Caco-2 cells. The concentrations of HSF2, IL-1β, and TNF-α in serum and IL-1β, and TNF-α in the supernatants of transfected Caco-2 cells were determined by ELISA.

RESULTS

HSF2 was differentially expressed in UC patients compared to normal controls. HSF2 expression was significantly higher in the intestinal mucosa of UC patients compared to other six groups. The results of immunohistochemistry, real time-PCR, Western Blots, and ELISA showed that the expression of HSF2 increased in parallel with the severity of UC. The serum concentration of HSF2 also positively correlated with levels of IL-1β and TNF-α. After down-regulation expression of HSF2 in Caco-2 cells by RNA interference, the productions of IL-1β and TNF-α stimulated by lipopolysaccharide (LPS) increased dramatically.

CONCLUSIONS

HSF2 appears to be a potential novel molecular marker for UC activity, and may provide a basis for studies on the pathogenesis and novel therapeutic targets for UC.

Normalization of mucosal cytokine gene expression levels predicts long-term remission after discontinuation of anti-TNF therapy in Crohn's disease

OBJECTIVE

To investigate mucosal cytokine gene expression levels in healed mucosa after anti-tumor necrosis factor (TNF) therapy in patients with Crohn's disease (CD) as possible risk factors for relapse after discontinuation of therapy.

DESIGN

Thirty-seven CD patients treated with anti-TNF agents until complete mucosal healing, documented by endoscopy, discontinued anti-TNF treatment and entered a follow-up study. Levels of mRNA expression of interleukin (IL)17A (IL17A), IL23, interferon-gamma (IFNG), TNF-alpha (TNF), IL10 and Forkhead Box P3 (FOXP3) were measured in biopsies from healed mucosa and analyzed as possible risk factors of relapse. Mucosal cytokine transcript levels from patients without CD served as controls.

RESULTS

Patients were followed after therapy withdrawal until relapse. Median time to relapse was 20 and 68 weeks for patients with elevated and normalized IL17A and TNF expression levels, respectively (p = 0.02 for IL17A and p = 0.003 for TNF, log-rank). Expression levels of TNF, IL17A and FOXP3 were significantly higher in patients who relapsed before 26 weeks than in those who did not relapse, and also higher in patients with relapse before week 52 versus non-relapsers. Elevated expression levels of TNF and IL17A in healed mucosa significantly increased the risk of relapse (HR = 3.4, p = 0.03, sensitivity 80%, specificity 38% and HR = 4.1, p = 0.008, sensitivity 81%, specificity 61%, respectively).

CONCLUSIONS

Normalization of mucosal gene expression of cytokines after anti-TNF therapy does not occur in all patients with healed mucosa as judged by endoscopy. Normalization of TNF and/or IL17A expression predicts long-term remission.

The effect of adalimumab for induction of endoscopic healing and normalization of mucosal cytokine gene expression in Crohn's disease

OBJECTIVE

To investigate the effects of adalimumab on the induction of complete endoscopic healing and normalization of mucosal cytokine gene expression in patients with active Crohn's disease.

MATERIAL AND METHODS

A prospective, single-center study including 77 patients. All were examined by endoscopy before initiation of adalimumab induction therapy with a minimum of six adalimumab injections. Patients were treated until documentation of complete endoscopic healing. Biopsies for measurements of mRNA expression levels of interleukin(IL)-17A (IL17A), IL23, interferon-gamma (IFNG), tumor necrosis factor-alpha (TNF), IL10 and Forkhead Box P3 (FOXP3), as well as for immunohistochemistry (IHC) were sampled at pre- and post-treatment endoscopy, and from 17 control patients.

RESULTS

Complete endoscopic healing was achieved in 27.3% after 10 weeks of treatment, documented by endoscopy at week 12. Cumulative endoscopic healing after 52 weeks was 44.2%. Complete endoscopic healing led to a significant reduction in mRNA expression levels for all cytokines except IL10. Elevated expression of TNF and IL-17A persisted in 52% and 76%, respectively, of patients with complete endoscopic remission. Pre-treatment cytokine gene expression levels did not predict response to adalimumab therapy.

CONCLUSIONS

Adalimumab induces accumulated complete endoscopic healing in 44% of patients after 52 weeks of therapy. Normalization of mucosal gene expression of cytokines does not occur in all patients with endoscopy-verified healed mucosa. Inclusion of normalized mucosal cytokine expression into the concept of mucosal healing could have an impact on long-term clinical outcome.

Construction of a eukaryotic expression plasmid encoding the human HSF2 gene and its expression in Caco-2 cells

AIM: To construct a eukaryotic expression plasmid encoding the human heat shock factor 2 (HSF2) gene and to examine its expression and localization in Caco-2 cells, a human colon adenocarcinoma cell line using FLAG tag as a reporter.

METHODS: The coding sequence of the HSF2 gene was amplified by PCR using human HSF2 cDNA as the template and subcloned into pCMV-Myc vector after digestion with EcoR I and Knp I. After the identity of recombinant plasmid was verified by direct sequencing, the plasmid was transfected into Caco-2 cells using Lipofectamine. Total RNA was extracted, reverse transcribed into cDNA, and tested by PCR. The expression of HSF2 and the recombinant fusion protein in Caco-2 cells was detected by Western blot. The expression and localization of HSF2 and the recombinant fusion protein in Caco-2 cells were observed by laser scanning confocal microscopy.

RESULTS: The coding sequence of the HSF2 gene was successfully inserted into the pCMV-Myc vector. Restriction enzyme digestion analysis showed that the length of the insert was 1557 bp, matching the expected size. The mRNA level of HSF2 in cells transfected with the recombinant plasmid was higher than those in non-transfected cells and cells transfected with empty vector. The expression of recombinant HSF2-FLAG fusion protein, which had a molecular weight of 70 kDa, was detected by Western blot. The expression of HSF2 in cells transfected with the recombinant plasmid increased dramatically in comparison with matched groups. The HSF2 and recombinant HSF2-FLAG protein were localized predominantly to the cytoplasm but partially aggregated around the nuclear envelope in Caco-2 cells.

CONCLUSION: The recombinant plasmid pCMV-HSF2-FLAG has been successfully constructed, which provides the basis for further study of possible roles of HSF2 in ulcerative colitis.

Mucosal cytokine gene expression profiles as biomarkers of response to infliximab in ulcerative colitis

OBJECTIVE

Mucosal cytokine profile determines T cell differentiation and may play an important role in the clinical course of inflammatory bowel disease (IBD). Cytokines from different T helper (Th) cell subsets are elevated in inflamed mucosa of patients with ulcerative colitis (UC), contributing to the inflammation. The aim of this study was to determine the predictive value of pre-treatment mucosal cytokine profile in response to therapy with the anti-TNF agent infliximab (IFX).

MATERIAL AND METHODS

The expression of Th1, Th17, Th2 and T-regulatory (Treg)-related cytokines was quantified by real-time PCR in mucosal biopsies from 74 UC patients before initiation of IFX induction therapy. Clinical and endoscopic effects were assessed after three infusions. Remission was defined as ulcerative colitis disease activity index (UCDAI) below 3.

RESULTS

Higher gene expression levels of IL-17A and IFN-γ were significantly associated with remission after three IFX infusions (OR = 5.4, p = 0.013 and OR = 5.5, p = 0.011, respectively). IL-17A and IFN-γ mRNA expression showed positive correlation. Th2 and Treg-related mediators were not significantly associated with clinical outcome, but were expressed at higher levels in UC patients compared with the controls. Immunohistochemistry (IHC) confirmed the presence of cells expressing both IL-17A and IFN-γ.

CONCLUSIONS

High expression of Th1- and Th17-related cytokines in the mucosa of UC patients can potentially predict a favorable outcome of IFX induction therapy. Th2 and Treg-related mediators do not appear useful as predictive markers.