Ingrid Arijs

Mucosal healing predicts long‐term outcome of maintenance therapy with infliximab in Crohn's disease

Background: Infliximab (IFX) treatment induces mucosal healing (MH) in patients with Crohns disease (CD) but the impact of MH on the long‐term outcome of IFX treatment in CD is still debated. Methods: We studied MH during long‐term treatment with IFX in 214 CD patients. A total of 183 patients (85.5%) responded to induction therapy and 31 patients (14.5%) were primary nonresponders. They underwent lower gastrointestinal (GI) endoscopy within a median of 0.7 months (interquartile range [IQR] 0.1–6.8) prior to first IFX and after a median of 6.7 months (IQR 1.4–24.6) after start of IFX and were further analyzed. The relationship between the outcome of IFX treatment long‐term and MH was studied. Results: MH was observed in 67.8% of the 183 initial responders (n = 124), with 83 patients having complete healing (45.4%) and 41 having partial healing (22.4%). Scheduled IFX treatment from the start resulted in MH more frequently (76.9% MH rate) than episodic treatment (61.0% MH rate; P = 0.0222, odds ratio [OR] 2.14, 95% confidence interval [CI] 1.11–4.12). Concomitant treatment with corticosteroids (CS) had a negative impact on MH (37.9% in patients with CS versus 63.2% in patients without CS; P = 0.021, OR 0.36, 95% CI 0.16–0.80). MH was associated with a significantly lower need for major abdominal surgery (MAS) during long‐term follow‐up (14.1% of patients with MH needed MAS versus 38.4% of patients without MH; P < 0.0001). Conclusions: MH induced by long‐term maintenance IFX treatment is associated with an improved long‐term outcome of the disease especially with a lower need for major abdominal surgeries. (Inflamm Bowel Dis 2009;)

Long-term outcome of treatment with infliximab in 614 patients with Crohn's disease: results from a single-centre cohort

Background and aims: This observational study assessed the long-term clinical benefit of infliximab (IFX) in 614 consecutive patients with Crohn’s disease (CD) from a single centre during a median follow-up of 55 months (interquartile range (IQR) 27–83). Methods: The primary analysis looked at the proportion of patients with initial response to IFX who had sustained clinical benefit at the end of follow-up. The long-term effects of IFX on the course of CD as reflected by the rate of surgery and hospitalisations and need for corticosteroids were also analysed. Results: 10.9% of patients were primary non-responders to IFX. Sustained benefit was observed in 347 of the 547 patients (63.4%) receiving long-term treatment. In 68.3% of these, treatment with IFX was ongoing and in 31.7% IFX was stopped, with the patient being in remission. Seventy patients (12.8%) had to stop IFX due to side effects and 118 (21.6%) due to loss of response. Although the yearly drop-out rates of IFX in patients with episodic (10.7%) and scheduled treatment (7.1%) were similar, the need for hospitalisations and surgery decreased less in the episodic than in the scheduled group. Steroid discontinuation also occurred in a higher proportion of patients in the scheduled group than in the episodic group. Conclusions: In this large real-life cohort of patients with CD, long-term treatment with IFX was very efficacious to maintain improvement during a median follow-up of almost 5 years and changed disease outcome by decreasing the rate of hospitalisations and surgery.

A decrease of the butyrate-producing species Roseburia hominis and Faecalibacterium prausnitzii defines dysbiosis in patients with ulcerative colitis

Objective Bacteria play an important role in the onset and perpetuation of intestinal inflammation in inflammatory bowel disease (IBD). Unlike in Crohns disease (CD), in which dysbiosis has been better characterised, in ulcerative colitis (UC), only small cohorts have been studied and showed conflicting data. Therefore, we evaluated in a large cohort if the microbial signature described in CD is also present in UC, and if we could characterise predominant dysbiosis in UC. To assess the functional impact of dysbiosis, we quantified the bacterial metabolites. Design The predominant microbiota from 127 UC patients and 87 age and sex-matched controls was analysed using denaturing gradient gel electrophoresis (DGGE) analysis. Differences were quantitatively validated using real-time PCR. Metabolites were quantified using gas chromatography–mass spectrometry. Results Based on DGGE analysis, the microbial signature previously described in CD was not present in UC. Real-time PCR analysis revealed a lower abundance of Roseburia hominis (p<0.0001) and Faecalibacterium prausnitzii (p<0.0001) in UC patients compared to controls. Both species showed an inverse correlation with disease activity. Short-chain fatty acids (SCFA) were reduced in UC patients (p=0.014), but no direct correlation between SCFA and the identified bacteria was found. Conclusions The composition of the fecal microbiota of UC patients differs from that of healthy individuals: we found a reduction in R hominis and F prausnitzii, both well-known butyrate-producing bacteria of the Firmicutes phylum. These results underscore the importance of dysbiosis in IBD but suggest that different bacterial species contribute to the pathogenesis of UC and CD.

Mucosal gene signatures to predict response to infliximab in patients with ulcerative colitis

Background and aims: Infliximab is an effective treatment for ulcerative colitis with over 60% of patients responding to treatment and up to 30% reaching remission. The mechanism of resistance to anti-tumour necrosis factor α (anti-TNFα) is unknown. This study used colonic mucosal gene expression to provide a predictive response signature for infliximab treatment in ulcerative colitis. Methods: Two cohorts of patients who received their first treatment with infliximab for refractory ulcerative colitis were studied. Response to infliximab was defined as endoscopic and histological healing. Total RNA from pre-treatment colonic mucosal biopsies was analysed with Affymetrix Human Genome U133 Plus 2.0 Arrays. Quantitative RT-PCR was used to confirm microarray data. Results: For predicting response to infliximab treatment, pre-treatment colonic mucosal expression profiles were compared for responders and non-responders. Comparative analysis identified 179 differentially expressed probe sets in cohort A and 361 in cohort B with an overlap of 74 probe sets, representing 53 known genes, between both analyses. Comparative analysis of both cohorts combined, yielded 212 differentially expressed probe sets. The top five differentially expressed genes in a combined analysis of both cohorts were osteoprotegerin, stanniocalcin-1, prostaglandin-endoperoxide synthase 2, interleukin 13 receptor alpha 2 and interleukin 11. All proteins encoded by these genes are involved in the adaptive immune response. These markers separated responders from non-responders with 95% sensitivity and 85% specificity. Conclusion: Gene array studies of ulcerative colitis mucosal biopsies identified predictive panels of genes for (non-)response to infliximab. Further study of the pathways involved should allow a better understanding of the mechanisms of resistance to infliximab therapy in ulcerative colitis. ClinicalTrials.gov number, NCT00639821.

Predictors of early response to infliximab in patients with ulcerative colitis.

Background Our objective is to report the outcome of infliximab (IFX) in ulcerative colitis (UC) patients from a single center and to identify predictors of early clinical response. Methods The first 100 UC patients (45 female; median age, 37.9 years) who received IFX at a single center were included. Eighty‐four patients received 5 mg/kg IFX, and 37 patients received a 3‐dose IFX induction at weeks 0, 2, and 6. The Mayo endoscopic subscore, assessed by sigmoidoscopy before inclusion, was 1, 2, and 3 in 5%, 52%, and 43% of patients, respectively. Sixty percent had pancolitis, 63% were on concomitant immunosuppressive therapy, 9% were active smokers, 64% had C‐reactive protein ≥5 mg/dL, and 44% were pANCA+/ASCA−. Five patients received IFX because of severe acute colitis refractory to intravenous corticosteroids. Results Early complete and partial clinical responses were observed in 41% and 24% of patients. Patients with early clinical response were significantly younger than nonresponders (median age, 35.7 versus 41.6 years, P = 0.041). Patients who were pANCA+/ASCA− had a significantly lower early clinical response (55% versus 76%; odds ratio [OR] = 0.40 (0.16–0.99), P = 0.049). Concomitant immunosuppressive therapy and the use of an IFX induction scheme did not influence early clinical response. Only 1 of 5 patients who received IFX for acute steroid‐refractory colitis required colectomy within 2 months. Conclusions IFX is an efficient therapy in UC, as shown by 65% early clinical response. A pANCA+/ASCA− serotype and an older age at first IFX infusion are associated with a suboptimal early clinical response. (Inflamm Bowel Dis 2006)

Mucosal Gene Expression of Antimicrobial Peptides in Inflammatory Bowel Disease Before and After First Infliximab Treatment

Background Antimicrobial peptides (AMPs) protect the host intestinal mucosa against microorganisms. Abnormal expression of defensins was shown in inflammatory bowel disease (IBD), but it is not clear whether this is a primary defect. We investigated the impact of anti-inflammatory therapy with infliximab on the mucosal gene expression of AMPs in IBD. Methodology/Principal Findings Mucosal gene expression of 81 AMPs was assessed in 61 IBD patients before and 4–6 weeks after their first infliximab infusion and in 12 control patients, using Affymetrix arrays. Quantitative real-time reverse-transcription PCR and immunohistochemistry were used to confirm microarray data. The dysregulation of many AMPs in colonic IBD in comparison with control colons was widely restored by infliximab therapy, and only DEFB1 expression remained significantly decreased after therapy in the colonic mucosa of IBD responders to infliximab. In ileal Crohns disease (CD), expression of two neuropeptides with antimicrobial activity, PYY and CHGB, was significantly decreased before therapy compared to control ileums, and ileal PYY expression remained significantly decreased after therapy in CD responders. Expression of the downregulated AMPs before and after treatment (DEFB1 and PYY) correlated with villin 1 expression, a gut epithelial cell marker, indicating that the decrease is a consequence of epithelial damage. Conclusions/Significance Our study shows that the dysregulation of AMPs in IBD mucosa is the consequence of inflammation, but may be responsible for perpetuation of inflammation due to ineffective clearance of microorganisms.

Mucosal gene expression of cell adhesion molecules, chemokines, and chemokine receptors in patients with inflammatory bowel disease before and after infliximab treatment

OBJECTIVES:Inflammatory bowel disease (IBD) is characterized by a continuous influx of leukocytes into the gut wall. This migration is regulated by cell adhesion molecules (CAMs), and selective antimigration therapies have been developed. This study investigated the effect of infliximab therapy on the mucosal gene expression of CAMs in IBD.METHODS:Mucosal gene expression of 69 leukocyte/endothelial CAMs and E-cadherin was investigated in 61 IBD patients before and after first infliximab infusion and in 12 normal controls, using Affymetrix gene expression microarrays. Quantitative reverse transcriptase-PCR (qRT-PCR), immunohistochemistry, and western blotting were used to confirm the microarray data.RESULTS:When compared with control colons, the colonic mucosal gene expression of most leukocyte/endothelial adhesion molecules was upregulated and E-cadherin gene expression was downregulated in active colonic IBD (IBDc) before therapy, with no significant colonic gene expression differences between ulcerative colitis and colonic Crohns disease. Infliximab therapy restored the upregulations of leukocyte CAMs in IBDc responders to infliximab that paralleled the disappearance of the inflammatory cells from the colonic lamina propria. Also, the colonic gene expression of endothelial CAMs and of most chemokines/chemokine receptors returned to normal after therapy in IBDc responders, and only CCL20 and CXCL1-2 expression remained increased after therapy in IBDc responders vs. control colons. When compared with control ileums, the ileal gene expression of MADCAM1, THY1, PECAM1, CCL28, CXCL1, -2, -5, -6, and -11, and IL8 was increased and CD58 expression was decreased in active ileal Crohns disease (CDi) before therapy, and none of the genes remained dysregulated after therapy in CDi responders vs. control ileums. This microarray study identified a number of interesting targets for antiadhesion therapy including PECAM1, IL8, and CCL20, besides the currently studied α4β7 integrin–MADCAM1 axis.CONCLUSIONS:Our data demonstrate that many leukocyte/endothelial CAMs and chemokines/chemokine receptors are upregulated in inflamed IBD mucosa. Controlling the inflammation with infliximab restores most of these dysregulations in IBD. These results show that at least part of the mechanism of anti-tumor necrosis factor-α therapy goes through downregulation of certain adhesion molecules.

Predictive value of epithelial gene expression profiles for response to infliximab in Crohn's disease.

Background: Infliximab (IFX) has become the mainstay of therapy of refractory Crohns disease (CD). However, a subset of patients shows incomplete or no response to this agent. In this study we investigated whether we could identify a mucosal gene panel to predict (non)response to IFX in CD. Methods: Mucosal biopsies were obtained during endoscopy from 37 patients with active CD (19 Crohns colitis [CDc] and 18 Crohns ileitis [CDi]) before and after first IFX treatment. Response was defined based on endoscopic and histologic findings. Total RNA was analyzed with Affymetrix Human Genome U133 Plus 2.0 Arrays. Quantitative real‐time reverse‐transcription polymerase chain reaction (RT‐PCR) was used to confirm microarray data. Results: At baseline, significant gene expression differences were found between CDc and CDi. For predicting response in CDc, comparative analysis of CDc pretreatment expression profiles identified 697 significant probe sets between CDc responders (n = 12) and CDc nonresponders (n = 7). Class prediction analysis of CDc top 20 and top 5 significant genes allowed complete separation between CDc responders and CDc nonresponders. The CDc top 5 genes were TNFAIP6, S100A8, IL11, G0S2, and S100A9. Only one patient with CDi completely healed the ileal mucosa. Even using less stringent response criteria, we could not identify a predictive gene panel for IFX responsiveness in CDi. Conclusions: This study identified a 100% accurate predictive gene signature for (non)response to IFX in CDc, whereas no such a predictive gene set could be identified for CDi. Inflamm Bowel Dis 2010

Regulatory macrophages induced by infliximab are involved in healing in vivo and in vitro.

Background: Regulatory macrophages play an important role in wound healing and gut homeostasis and have antiinflammatory properties. Induction of this cell type (M&psgr;ind) by the anti‐tumor necrosis factor (TNF) antibodies, infliximab and adalimumab, has recently been shown in vitro. Also, the superiority of infliximab/azathioprine combination therapy over infliximab or azathioprine monotherapy has recently been established, but the mechanism behind this remains unclear. The aim of this study was to examine the induction of regulatory macrophages in patients with and without mucosal healing in response to infliximab. In addition, we studied the effect of infliximab/azathioprine combination treatment on the differentiation and function of regulatory macrophages. Methods: Inflammatory bowel disease (IBD) patients (n = 10) underwent endoscopy before and after first infliximab treatment. Immunohistochemical staining of CD68 and CD206 was performed in all patients. Mixed lymphocyte reactions (MLRs) were treated with infliximab, azathioprine, or both. Macrophage phenotype was evaluated by flow cytometry and inhibition of T‐cell proliferation was measured in a secondary MLR containing macrophages and third‐party lymphocytes. Results: A significant induction of regulatory macrophages was observed in patients with mucosal healing after treatment with infliximab; this induction was absent in patients without mucosal healing. In addition, M&psgr;ind have the ability to induce wound healing in an in vitro model, further suggesting a key role for infliximab‐induced macrophages in mucosal healing. Upon infliximab/azathioprine combination treatment, an increased number of regulatory macrophages was observed. These macrophages also displayed stronger immunosuppressive properties than macrophages induced by infliximab monotherapy. Conclusions: These data show that regulatory macrophages may be involved in mucosal healing and provide a rationale for the superiority of infliximab/azathioprine combination treatment observed in the clinic. (Inflamm Bowel Dis 2012;)

Reciprocal changes of Foxp3 expression in blood and intestinal mucosa in IBD patients responding to infliximab.

Background: Immune therapies may act in inflammatory bowel diseases (IBD) by modulating regulatory T cells (Tregs). Therefore, we investigated the effect of infliximab (IFX) therapy on Forkhead box protein3 (Foxp3) T cells in blood and intestinal mucosa from Crohns disease (CD) and ulcerative colitis (UC). Methods: Forty patients with active IBD (23 CD / 17 UC) were treated with IFX 5 mg/kg intravenously at weeks 0, 2, 6, and each 8 weeks thereafter. Blood samples were obtained before every infusion and T‐lymphocyte subsets were characterized by flow cytometry. Foxp3 expression in intestinal biopsies from 43 patients with active IBD (19 CD / 24 UC) before and after IFX infusion and from 6 controls were assessed by quantitative reverse‐transcription polymerase chain reaction and immunohistochemistry. Plasma C‐reactive protein (CRP), clinical response, and endoscopic healing data were collected in parallel. Results: IFX therapy resulted in a significant and sustained relative increase of CD4+CD25+Foxp3+ Treg and of CD4+CD25−Foxp3+ Treg cells in peripheral blood (both P < 0.0001 compared to baseline), particularly in responders (both P < 0.05 compared to nonresponders). The change in CRP over time inversely correlated with the increase of CD25+Foxp3+ cells (P < 0.001, r = −0.39) and durable clinical response was associated with a sustained increase of circulating Foxp3+ cells. Surprisingly, IFX therapy downregulated mucosal mRNA and protein expression of Foxp3 in UC and CD responders (both P < 0.001) but not in nonresponders. Conclusions: IFX therapy has opposite effects in Foxp3+ Treg cells in blood and gut mucosa, which suggests a redistribution of this important T‐cell subset. Inflamm Bowel Dis 2010