Wouter T. van Haaften

Fragments of Citrullinated and MMP-degraded Vimentin and MMP-degraded Type III Collagen Are Novel Serological Biomarkers to Differentiate Crohn’s Disease from Ulcerative Colitis

BACKGROUND AND AIMS A hallmark of inflammatory bowel disease [IBD] is chronic inflammation, which leads to excessive extracellular matrix [ECM] remodelling and release of specific protein fragments, called neoepitopes. We speculated that the biomarker profile panel for ulcerative colitis [UC] and Crohns disease [CD] represent a heterogeneous expression pattern, and may be applied as a tool to aid in the differentiation between UC and CD. METHODS Serum biomarkers of degraded collagens I, III-IV [C1M, C3M, and C4M], collagen type 1 and IV formation [P1NP, P4NP], and citrullinated and MMP-degraded vimentin [VICM] were studied with a competitive ELISA assay system in a cohort including 164 subjects [CD n = 72, UC n = 60, and non-IBD controls n = 32] and a validation cohort of 61 subjects [CD n = 46, and UC n = 15]. Receiver operating characteristic curve analysis and logistic regression modelling were carried out to evaluate the discriminative power of the biomarkers. RESULTS All biomarkers were corrected for confounding factors. VICM and C3M demonstrated the highest diagnostic power, alone, to differentiate CD from UC with an area under the curve [AUC] of 0.77 and 0.69, respectively. Furthermore, the biomarkers C1M [AUC = 0.81], C3M [AUC = 0.83], VICM [AUC = 0.83], and P1NP [AUC = 0.77] were best to differentiate UC from non-IBD. The best combinations of biomarkers to differentiate CD from UC and UC from non-IBD were VICM, C3M, C4M [AUC = 0.90] and VICM, C3M [AUC = 0.98] respectively. CONCLUSIONS Specific extracellular matrix degradation markers are elevated in IBD and can discriminate CD from UC and UC from non-IBD controls with a high diagnostic accuracy.

Precision‐cut rat, mouse, and human intestinal slices as novel models for the early‐onset of intestinal fibrosis

Intestinal fibrosis (IF) is a major complication of inflammatory bowel disease. IF research is limited by the lack of relevant in vitro and in vivo models. We evaluated precision‐cut intestinal slices (PCIS) prepared from human, rat, and mouse intestine as ex vivo models mimicking the early‐onset of (human) IF. Precision‐cut intestinal slices prepared from human (h), rat (r), and mouse (m) jejunum, were incubated up to 72 h, the viability of PCIS was assessed by ATP content and morphology, and the gene expression of several fibrosis markers was determined. The viability of rPCIS decreased after 24 h of incubation, whereas mPCIS and hPCIS were viable up to 72 h of culturing. Furthermore, during this period, gene expression of heat shock protein 47 and plasminogen activator inhibitor 1 increased in all PCIS in addition to augmented expression of synaptophysin in hPCIS, fibronectin (Fn2) and TGF‐β1 in rPCIS, and Fn2 and connective tissue growth factor (Ctgf) in mPCIS. Addition of TGF‐β1 to rPCIS or mPCIS induced the gene expression of the fibrosis markers Pro‐collagen1a1, Fn2, and Ctgf in both species. However, none of the fibrosis markers was further elevated in hPCIS. We successfully developed a novel ex vivo model that can mimic the early‐onset of fibrosis in the intestine using human, rat, and mouse PCIS. Furthermore, in rat and mouse PCIS, TGF‐β1 was able to even further increase the gene expression of fibrosis markers. This indicates that PCIS can be used as a model for the early‐onset of IF.

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.

The oxysterol synthesizing enzyme CH25H contributes to the development of intestinal fibrosis

Intestinal fibrosis and stenosis are common complications of Crohn’s disease (CD), frequently requiring surgery. Anti-inflammatory strategies can only partially prevent fibrosis; hence, anti-fibrotic therapies remain an unmet clinical need. Oxysterols are oxidized cholesterol derivatives, with important roles in various biological processes. The enzyme cholesterol 25-hydroxylase (CH25H) converts cholesterol to 25-hydroxycholesterol (25-HC), which modulates immune responses and oxidative stress. In human intestinal samples from CD patients we found a strong correlation of CH25H mRNA expression with the expression of fibrosis markers. We demonstrate reduced intestinal fibrosis in mice deficient for the CH25H enzyme using the sodium dextran sulfate (DSS)-induced chronic colitis model. Additionally, using a heterotopic transplantation model of intestinal fibrosis, we demonstrate reduced collagen deposition and lower concentrations of hydroxyproline in CH25H knockouts. In the heterotopic transplant model, CH25H was expressed in fibroblasts. Taken together, our findings indicate an involvement of oxysterol synthesis in the pathogenesis of intestinal fibrosis.

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 Crohns 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.