The Citrullinated and MMP-degraded Vimentin Biomarker (VICM) Predicts Early Response to Anti-TNFα Treatment in Crohn's Disease.

BACKGROUND: In Crohn's disease (CD), 10% to 40% of patients do not respond to anti-tumor necrosis factor-α (TNFα) treatment. Currently, there are no biomarkers with adequate sensitivity to separate responders from nonresponders at an early stage. AIM: The aim of this study was to investigated whether early changes in the VICM (citrullinated and matrix metalloproteinase-degraded vimentin) biomarker were associated with response to anti-TNFα treatment in patients with CD. METHODS: Serum VICM levels were measured by ELISA in 2 independent cohorts of CD patients (n=42) treated with anti-TNFα (infliximab or adalimumab). Response was determined by achieving clinical remission (Harvey Bradshaw Index<5). RESULTS: Compared with baseline, VICM serum levels were reduced by anti-TNFα in the infliximab cohort (week 6 and 14) and in the adalimumab cohort (week 8). VICM was lower in the responders compared with the nonresponders [infliximab: week 6, P<0.05; area under the curve (AUC)=0.90; adalimumab: week 1, P<0.01 (AUC=0.91), and week 8, P<0.05 (AUC=0.86)], and were able to predict response to treatment after 1 week of treatment with an odds ratio of 42.5. CONCLUSIONS: The VICM biomarker was time dependently reduced in CD patients responding to anti-TNFα treatment. We suggest that VICM may be used as a marker for monitoring early response to anti-TNFα in patients with CD.

Serological Biomarkers of Tissue Turnover Identify Responders to Anti-TNF Therapy in Crohn's Disease: A Pilot Study.

INTRODUCTION: Anti-tumor necrosis factor (TNF) therapy is effective in inducing remission in Crohn's disease in 60% of patients. No serological biomarkers are available, which can predict response to anti-TNF. We aimed to investigate serological markers of collagen turnover reflecting tissue inflammation as predictors of response to anti-TNF. METHODS: In 2 retrospective observational cohorts, markers for matrix metalloproteinase-degraded type III and IV collagens (C3M and C4M, respectively) and for formation of type III and IV collagens (PRO-C3 and PRO-C4, respectively) were measured in serum and compared with standard C-reactive protein in patients with active Crohn's disease who started infliximab (IFX, n = 21) or adalimumab (ADA, n = 21). Disease activity was classified by the Harvey-Bradshaw index (active disease ≥5); response was defined as clinical remission. RESULTS: Seventeen patients (81%) treated with IFX were in remission at week 14; 15 patients (71%) treated with ADA were in remission at week 8. Serum C4M at baseline was increased in nonresponders compared with responders (IFX: 35.0 ± 2.4 vs 23.2 ± 2.6, P = 0.04, ADA: 53.0 ± 3.2 vs 34.1 ± 2.8, P = 0.006). C4M levels at baseline predicted response in both cohorts (IFX: odds ratio 39 [95% confidence interval, 2.4-523.9] P = 0.02, cutoff 35.2 nmol/L; ADA: odds ratio 26 [95% confidence interval, 1.8-332.5], P = 0.01, cutoff 46.9 nmol/L). C-reactive protein was not able to predict response to anti-TNF. DISCUSSION: Response to anti-TNF therapy within the first 14 weeks of treatment can be predicted based on baseline levels of basement membrane marker C4M. This marker could be used as biomarker for response to anti-TNF and could aid in early therapy decision making. Validation in larger well-defined cohorts is needed.

Long noncoding RNA H19X is a key mediator of TGF-ß-driven fibrosis.

TGF-ß is a master regulator of fibrosis, driving the differentiation of fibroblasts into apoptosis-resistant myofibroblasts and sustaining the production of extracellular matrix (ECM) components. Here, we identified the nuclear long noncoding RNA (lncRNA) H19X as a master regulator of TGF-ß-driven tissue fibrosis. H19X was consistently upregulated in a wide variety of human fibrotic tissues and diseases and was strongly induced by TGF-ß, particularly in fibroblasts and fibroblast-related cells. Functional experiments following H19X silencing revealed that H19X was an obligatory factor for TGF-ß-induced ECM synthesis as well as differentiation and survival of ECM-producing myofibroblasts. We showed that H19X regulates DDIT4L gene expression, specifically interacting with a region upstream of the DDIT4L gene and changing the chromatin accessibility of a DDIT4L enhancer. These events resulted in transcriptional repression of DDIT4L and, in turn, in increased collagen expression and fibrosis. Our results shed light on key effectors of TGF-ß-induced ECM remodeling and fibrosis.

Peribiliary Glands Are Key in Regeneration of the Human Biliary Epithelium After Severe Bile Duct Injury.

Peribiliary glands (PBG) are a source of stem/progenitor cells organized in a cellular network encircling large bile ducts. Severe cholangiopathy with loss of luminal biliary epithelium has been proposed to activate PBG, resulting in cell proliferation and differentiation to restore biliary epithelial integrity. However, formal evidence for this concept in human livers is lacking. We therefore developed an ex vivo model using precision-cut slices of extrahepatic human bile ducts obtained from discarded donor livers, providing an intact anatomical organization of cell structures, to study spatiotemporal differentiation and migration of PBG cells after severe biliary injury. Postischemic bile duct slices were incubated in oxygenated culture medium for up to a week. At baseline, severe tissue injury was evident with loss of luminal epithelial lining and mural stroma necrosis. In contrast, PBG remained relatively well preserved and different reactions of PBG were noted, including PBG dilatation, cell proliferation, and maturation. Proliferation of PBG cells increased after 24 hours of oxygenated incubation, reaching a peak after 72 hours. Proliferation of PBG cells was paralleled by a reduction in PBG apoptosis and differentiation from a primitive and pluripotent (homeobox protein Nanog+/ sex-determining region Y-box 9+) to a mature (cystic fibrosis transmembrane conductance regulator+/secretin receptor+) and activated phenotype (increased expression of hypoxia-inducible factor 1 alpha, glucose transporter 1, and vascular endothelial growth factor A). Migration of proliferating PBG cells in our ex vivo model was unorganized, but resulted in generation of epithelial monolayers at stromal surfaces. Conclusion: Human PBG contain biliary progenitor cells and are able to respond to bile duct epithelial loss with proliferation, differentiation, and maturation to restore epithelial integrity. The ex vivo spatiotemporal behavior of human PBG cells provides evidence for a pivotal role of PBG in biliary regeneration after severe injury.

Intestinal Activation of pH-Sensing Receptor OGR1 [GPR68] Contributes to Fibrogenesis.

BACKGROUND AND AIMS: pH-sensing ovarian cancer G-protein coupled receptor-1 [OGR1/GPR68] is regulated by key inflammatory cytokines. Patients suffering from inflammatory bowel diseases [IBDs] express increased mucosal levels of OGR1 compared with non-IBD controls. pH-sensing may be relevant for progression of fibrosis, as extracellular acidification leads to fibroblast activation and extracellular matrix remodelling. We aimed to determine OGR1 expression in fibrotic lesions in the intestine of Crohn's disease [CD] patients, and the effect of Ogr1 deficiency in fibrogenesis. METHODS: Human fibrotic and non-fibrotic terminal ileum was obtained from CD patients undergoing ileocaecal resection due to stenosis. Gene expression of fibrosis markers and pH-sensing receptors was analysed. For the initiation of fibrosis in vivo, spontaneous colitis by Il10-/-, dextran sodium sulfate [DSS]-induced chronic colitis and the heterotopic intestinal transplantation model were used. RESULTS: Increased expression of fibrosis markers was accompanied by an increase in OGR1 [2.71 ± 0.69 vs 1.18 ± 0.03, p = 0.016] in fibrosis-affected human terminal ileum, compared with the non-fibrotic resection margin. Positive correlation between OGR1 expression and pro-fibrotic cytokines [TGFB1 and CTGF] and pro-collagens was observed. The heterotopic animal model for intestinal fibrosis transplanted with terminal ileum from Ogr1-/- mice showed a decrease in mRNA expression of fibrosis markers as well as a decrease in collagen layer thickness and hydroxyproline compared with grafts from wild-type mice. CONCLUSIONS: OGR1 expression was correlated with increased expression levels of pro-fibrotic genes and collagen deposition. Ogr1 deficiency was associated with a decrease in fibrosis formation. Targeting OGR1 may be a potential new treatment option for IBD-associated fibrosis.

Histopathologic and molecular evaluation of the Organ Procurement and Transplantation Network selection criteria for intestinal graft donation.

BACKGROUND: The Organ Procurement and Transplantation Network (OPTN) has formulated criteria for the selection of donors for intestinal transplantation. To date, however, no study has correlated histologic findings of intestinal injury with the OPTN criteria. We aimed to describe histopathologic and molecular features of allograft injury in relation to donor conditions defined by the OPTN criteria. MATERIALS AND METHODS: Graft histology (Park Score), Claudin-3 staining, systemic inflammatory markers (C-reactive protein/lipopolysaccharide-binding protein) and expression of heat shock protein 70, heme oxygenase 1, and interleukin 6 were evaluated in multiorgan deceased donors (donation after brain death [DBD] and donation after cardiac death [DCD]). RESULTS: Ninety-seven samples (52 jejunum/45 ileum) were recovered from 59 donors (46 DBD/13 DCD). The OPTN criterion cold ischemia time correlated with histologic injury (Park score) to which the jejunum appeared more susceptible than the ileum. Claudin-3 staining was higher, and heat shock protein 70 expression lower in donors meeting the OPTN criteria compared with donors not meeting the criteria and in DBD versus DCD. In DBD donors, interleukin 6 expression was higher compared with DCD donors and inversely related to C-reactive protein. CONCLUSIONS: Our multiparameter analysis suggests that the OPTN criteria can be discriminative concerning intestinal graft quality. Our data suggest that DCD intestinal allografts are qualitatively inferior and that the jejunum is more sensitive to ischemia than the ileum.