Non-TGFß profibrotic signaling in ulcerative colitis after in vivo experimental intestinal injury in humans.

Although impaired regeneration is important in many gastrointestinal diseases including ulcerative colitis (UC), the dynamics of mucosal regeneration in humans are poorly investigated. We have developed a model to study these processes in vivo in humans. Epithelial restitution (ER) and extracellular matrix (ECM) regulation after an experimental injury of the sigmoid colonic mucosa was assessed by repeated high-resolution endoscopic imaging, histological assessment, RNA sequencing, deconvolution analysis, and 16S rDNA sequencing of the injury niche microbiome of 19 patients with UC in remission and 20 control subjects. Human ER had a 48-h lag before induction of regenerative epithelial cells [wound-associated epithelial (WAE) and transit amplifying (TA) cells] along with the increase of fibroblast-derived stem cell growth factor gremlin 1 mRNA (GREM1). However, UC deconvolution data showed rapid induction of inflammatory fibroblasts and upregulation of major structural ECM collagen mRNAs along with tissue inhibitor of metalloproteinase 1 (TIMP1), suggesting increased profibrotic ECM deposition. No change was seen in transforming growth factor ß (TGFß) mRNA, whereas the profibrotic cytokines interleukin 13 (IL13) and IL11 were upregulated in UC, suggesting that human postinjury responses could be TGFß-independent. In conclusion, we found distinct regulatory layers of regeneration in the normal human colon and a potential targetable profibrotic dysregulation in UC that could lead to long-term end-organ failure, i.e., intestinal damage.NEW & NOTEWORTHY The study reveals the regulatory dynamics of epithelial regeneration and extracellular matrix remodeling after experimental injury of the human colon in vivo and shows that human intestinal regeneration is different from data obtained from animals. A lag phase in epithelial restitution is associated with induction of stromal cell-derived epithelial growth factors. Postinjury regeneration is transforming growth factor ß-independent, and we find a profibrotic response in patients with ulcerative colitis despite being in remission.

Identification, isolation and analysis of human gut-associated lymphoid tissues.

Gut-associated lymphoid tissues (GALTs) comprise key intestinal immune inductive sites, including the Peyer's patches of the small intestine and different types of isolated lymphoid follicle (ILF) found along the length of the gut. Our understanding of human GALT is limited due to a lack of protocols for their isolation. Here we describe a technique that, uniquely among intestinal cell isolation protocols, allows identification and isolation of all human GALT, as well as GALT-free intestinal lamina propria (LP). The technique involves the mechanical separation of intestinal mucosa from the submucosa, allowing the identification and isolation of submucosal ILF (SM-ILF), LP-embedded mucosal ILF (M-ILF) and LP free of contaminating lymphoid tissue. Individual SM-ILF, M-ILF and Peyer's patch follicles can be subsequently digested for downstream cellular and molecular characterization. The technique, which takes 4-10 h, will be useful for researchers interested in intestinal immune development and function in health and disease.

Altered Structural Expression and Enzymatic Activity Parameters in Quiescent Ulcerative Colitis: Are These Potential Normalization Criteria?

Mucosal healing determined by endoscopy is currently the remission standard for ulcerative colitis (UC). However, new criteria for remission are emerging, such as histologic normalization, which appears to correlate better to the risk of relapse. Here, we study mucosal healing on a molecular and functional level in quiescent UC. We obtained endoscopic biopsies from 33 quiescent UC patients and from 17 controls. Histology was assessed using Geboes score. Protein and mRNA levels were evaluated for the tight junction proteins claudin-2, claudin-4, occludin, and tricellulin, as well as Cl-/HCO3- exchanger DRA, and cyclo-oxygenase enzymes (COX-1, COX-2). The mucosal activity of COX-1 and COX-2 enzymes was assessed in modified Ussing chambers, measuring electrogenic ion transport (short-circuit current, SCC). Chronic inflammation was present in most UC patients. The protein level of claudin-4 was reduced, while mRNA-levels of claudin-2 and claudin-4 were upregulated in UC patients. Surprisingly, the mRNA level of COX-1 was downregulated, but was unaltered for COX-2. Basal ion transport was not affected, while COX-2 inhibition induced a two-fold larger decrease in SCC in UC patients. Despite being in clinical and endoscopic remission, quiescent UC patients demonstrated abnormal mucosal barrier properties at the molecular and functional level. Further exploration of mucosal molecular signature for revision of current remission standards should be considered.

Dual Inhibition of EGFR and VEGF in Heavily Pretreated Patients with Metastatic Colorectal Cancer.

OBJECTIVE: The aim of this study was to evaluate the efficacy and safety of combining irinotecan, bevacizumab, and cetuximab/panitumumab as a 4th-line treatment in patients with metastatic colorectal cancer. METHODS: All patients had KRAS wild-type metastatic colorectal cancer and had previously received fluoropyrimidine, oxaliplatin, irinotecan, and cetuximab/panitumumab in a 1st, 2nd, and 3rd line setting. Most patients had previously received bevacizumab as well. All patients had progressed within 3 months after the last given treatment before starting the triple combination therapy every second week. RESULTS: Sixty-three patients were evaluated. The triple combination therapy was well tolerated. The median progression-free survival was 6.1 months, and the median overall survival was 11.9 months. Four patients (6%) obtained a partial response, and 40 (63%) had stable disease. CONCLUSION: The combination of irinotecan, bevacizumab, and cetuximab/panitumumab is safe and shows a toxicity profile corresponding to what is expected from the agents alone. The results indicate that the combination in the 4th line may result in a high rate of disease control in heavily pretreated patients with metastatic colorectal cancer.

F-calprotectin and Blood Markers Correlate to Quality of Life in Pediatric Inflammatory Bowel Disease.

OBJECTIVES: Our aim was to investigate predictors of health-related quality of life (HRQoL) with respect to changes in disease parameters over time in children with inflammatory bowel disease. METHODS: This was a prospective longitudinal study examining the association between HRQoL (IMPACT III) and symptom scores (Pediatric Crohn Disease Activity Index, abbreviated Pediatric Ulcerative Colitis Activity Index), fecal calprotectin measures and blood analyses (C-reactive protein, erythrocyte sedimentation rate, orosomucoid, albumin, hemoglobin, and vitamin-D) in a cohort of 10- to 17-year-old patients with inflammatory bowel disease. Data were collected prospectively at 3-month intervals during a 2-year period. Associations were analyzed using linear mixed-effect models. Patients were divided into 2 groups, which received nonbiological oral treatment or biological parenteral treatment. RESULTS: From 79 patients (39 Crohn disease/40 ulcerative colitis), representing a total of 43,132 days of observation, 572 IMPACT measurements were paired with variables. A decrease in the IMPACT III score was significantly associated with increased ulcerative colitis-symptom score in the biological group (P = 0.005), and a similar inverse tendency was found in the nonbiological group and for Crohn disease symptoms in both groups. We found in both treatment groups overall a significant (P < 0.05) inverse association between the IMPACT III and the levels of fecal calprotectin, erythrocyte sedimentation rate, and orosomucoid, whereas albumin, hemoglobin, and vitamin-D were directly significantly associated. CONCLUSIONS: The IMPACT score, already known to correlate with disease activity, has now been shown to be associated with disease markers in feces and blood. This emphasizes that objective markers of disease activity indirectly can predict the patient's HRQoL.

Transcriptional analysis of left-sided colitis, pancolitis, and ulcerative colitis-associated dysplasia.

BACKGROUND: It is unknown why patients with extensive ulcerative colitis (UC) have a higher risk of colorectal cancer compared with patients with left-sided UC. This study characterizes the inflammatory processes in left-sided UC, pancolitis, and UC-associated dysplasia at the transcriptional level to identify potential biomarkers and transcripts of importance for the carcinogenic behavior of chronic inflammation. METHODS: The Affymetrix GeneChip Human Genome U133 Plus 2.0 was applied on colonic biopsies from UC patients with left-sided UC, pancolitis, dysplasia, and controls. Reverse transcription polymerase chain reaction and immunohistochemistry were performed for validating selected transcripts in the initial cohort and in 2 independent cohorts of patients with UC. Microarray data were analyzed by principal component analysis, and reverse transcription polymerase chain reaction and immunohistochemistry data by the Wilcoxon's rank-sum test. RESULTS: The principal component analysis results revealed separate clusters for left-sided UC, pancolitis, dysplasia, and controls. Close clustering of dysplastic and pancolitic samples indicated similarities in gene expression. Indeed, 101 and 656 parallel upregulated and downregulated transcripts, respectively, were identified in specimens from dysplasia and pancolitis. Validation of selected transcripts hereof identified insulin receptor alpha (INSRA) and MAP kinase interacting serine/threonine kinase 2 (MKNK2) with an enhanced expression in dysplasia compared with left-sided UC and controls, whereas laminin γ2 (LAMC2) was found with a lower expression in dysplasia compared with the remaining 3 groups. CONCLUSIONS: This study demonstrates pancolitis and left-sided UC as distinct inflammatory processes at the transcriptional level, and identifies INSRA, MKNK2, and LAMC2 as potential critical transcripts in the inflammation-driven preneoplastic process of UC.