Keratin 7 expression in different anatomical parts of colonic epithelium in inflammatory bowel diseases and its prognostic value: a 3-year follow-up study.

The diagnosis of inflammatory bowel diseases (IBD) may be challenging and their clinical course, characterized by relapses and spontaneous or drug-induced remissions, is difficult to predict. Novel prognostic biomarkers are needed. Keratin 7 (K7) is a cytoskeletal intermediate filament protein which is not normally expressed in the colonic epithelium. It was recently shown that K7 expression in the colonic epithelium is associated with ulcerative colitis and Crohn's disease, the two main subtypes of IBD. Here we investigated IBD associated K7 neo-expression in different regions of colon and terminal ileum. The correlation of the K7 expression with the inflammatory activity of the epithelium was analyzed in each region. The prognostic value of K7 was estimated by comparing the clinical disease activity after 3 years with the K7 expression at the time of enrollment. Our data shows that the level of K7 expression in inflamed epithelium varies depending on the anatomical region and it is the most pronounced in ascending and descending colon, but it did not predict the severity of IBD for the following 3 years. These results warrant future studies focusing on the biological role of K7 in colon and its utilization as potential IBD biomarker.

Colonocyte keratin 7 is expressed de novo in inflammatory bowel diseases and associated with pathological changes and drug-resistance.

The clinical course of IBD, characterized by relapses and remissions, is difficult to predict. Initial diagnosis can be challenging, and novel disease markers are needed. Keratin 7 (K7) is a cytoskeletal intermediate filament protein not expressed in the colonic epithelium but has been reported in IBD-associated colorectal tumors. Our aim was to analyze whether K7 is expressed in chronic colonic inflammatory diseases and evaluate its potential as a novel biomarker. K7 was analyzed in two patient cohorts using immunohistochemistry-stained colon samples and single-cell quantitative digital pathology methods. K7 was correlated to pathological changes and clinical patient characteristics. Our data shows that K7 is expressed de novo in the colonic epithelium of ulcerative colitis and Crohn's disease IBD patients, but not in collagenous or lymphocytic colitis. K7 mRNA expression was significantly increased in colons of IBD patients compared to controls when assessed in publicly available datasets. While K7 increased in areas with inflammatory activity, it was not expressed in specific crypt compartments and did not correlate with neutrophils or stool calprotectin. K7 was increased in areas proximal to pathological alterations and was most pronounced in drug-resistant ulcerative colitis. In conclusion, colonic epithelial K7 is neo-expressed selectively in IBD patients and could be investigated for its potential as a disease biomarker.

The value of combined positron emission tomography/magnetic resonance imaging to diagnose inflammatory bowel disease: a prospective study.

BACKGROUND: The clinical utility of positron emission tomography/magnetic resonance imaging (PET/MRI) in comparison to standard work-up with patients with known or suspected inflammatory bowel disease (IBD) is unknown. PURPOSE: To evaluate the value of 18F-fluorodeoxyglucose (18F-FDG) PET/MRI in the diagnostics of IBD and further compare the data obtained using PET/MRI to histological findings. MATERIALS AND METHODS: Ten patients with relapse in IBD or with symptoms of suspected IBD were recruited either from a gastroenterology outpatient clinic or from a hospital ward. Intestinal inflammation was assessed with histology and 18F-FDG PET/MRI. Maximum standard uptake values (SUVmax) were calculated in six regions of the intestine (small bowel, ascending, transverse, descending and sigmoid colon, and rectum) and compared to histological analysis of inflammation activity. RESULTS: The study showed that both the inflammation activity (P = 0.008) and the region of the biopsy in the intestine (P = 0.015) had a significant effect on SUV. SUVs obtained from severe inflammation activity emerged significantly from the background (P = 0.006). In addition, the SUVs obtained from moderate inflammation raised from background, but the difference was not statistically significant (P = 0.083), while SUVs of mild inflammation were at the same level with SUVs of normal bowel wall (P = 0.988). CONCLUSION: 18F-FDG PET/MRI is a promising method of detecting especially severe inflammatory bowel lesions. More data are required to define its sensitivity and specificity.