Disease Activity Patterns, Mortality, and Colorectal Cancer Risk in Microscopic Colitis: A Danish Nationwide Cohort Study, 2001 to 2016.

BACKGROUND AND AIMS: The disease course of microscopic colitis [MC], encompassing collagenous colitis [CC] and lymphocytic colitis [LC], is not well known. In a Danish nationwide cohort, we evaluated the disease activity patterns as well as the risk of colorectal cancer [CRC] and mortality based on disease severity. METHODS: All incident MC patients [n = 14 302] with a recorded diagnosis of CC [n = 8437] or LC [n = 5865] in the Danish Pathology Register, entered between 2001 and 2016, were matched to 10 reference individuals [n = 142 481]. Incident cases of CRC after the index date were captured from the Danish Cancer Registry. Mortality data were ascertained from the Danish Registry of Causes of Death, and information about treatment was obtained from the Danish National Prescription Registry. The risk of CRC and mortality analyses were investigated by Cox regression and Kaplan-Meier estimates. RESULTS: We identified a self-limiting or transient disease course in 70.6% of LC patients and in 59.9% of CC patients, p <0.001. Less than 5% of MC patients experienced a budesonide-refractory disease course and were treated with immunomodulators or biologic treatment. A total of 2926 [20.5%] MC patients and 24 632 [17.3%] reference individuals died during the study period. MC patients with a severe disease had a relative risk [RR] of mortality of 1.41 (95% confidence interval [CI]: 1.32-1.50) compared with reference individuals. Only 90 MC patients were diagnosed with CRC during follow-up, corresponding to an RR of 0.48 [95% CI: 0.39-0.60]. CONCLUSIONS: A majority of MC patients experience an indolent disease course with a lower risk of developing CRC compared with the background population.

Proteomics dataset: The colon mucosa from inflammatory bowel disease patients, gastrointestinal asymptomic rheumatoid arthritis patients, and controls.

The datasets presented in this article are related to the research articles entitled "Neutrophil Extracellular Traps in Ulcerative Colitis: A Proteome Analysis of Intestinal Biopsies" (Bennike et al., 2015 [1]), and "Proteome Analysis of Rheumatoid Arthritis Gut Mucosa" (Bennike et al., 2017 [2]). The colon mucosa represents the main interacting surface of the gut microbiota and the immune system. Studies have found an altered composition of the gut microbiota in rheumatoid arthritis patients (Zhang et al., 2015; Vaahtovuo et al., 2008; Hazenberg et al., 1992) [5], [6], [7] and inflammatory bowel disease patients (Morgan et al., 2012; Abraham and Medzhitov, 2011; Bennike, 2014) [8], [9], [10]. Therefore, we characterized the proteome of colon mucosa biopsies from 10 inflammatory bowel disease ulcerative colitis (UC) patients, 11 gastrointestinal healthy rheumatoid arthritis (RA) patients, and 10 controls. We conducted the sample preparation and liquid chromatography mass spectrometry (LC-MS/MS) analysis of all samples in one batch, enabling label-free comparison between all biopsies. The datasets are made publicly available to enable critical or extended analyses. The proteomics data and search results, have been deposited to the ProteomeXchange Consortium via the PRIDE partner repository with the dataset identifiers PXD001608 for ulcerative colitis and control samples, and PXD003082 for rheumatoid arthritis samples.

Proteome Analysis of Rheumatoid Arthritis Gut Mucosa.

Rheumatoid arthritis (RA) is an inflammatory joint disease leading to cartilage damage and ultimately impaired joint function. To gain new insight into the systemic immune manifestations of RA, we characterized the colon mucosa proteome from 11 RA-patients and 10 healthy controls. The biopsies were extracted by colonoscopy and analyzed by label-free quantitative proteomics, enabling the quantitation of 5366 proteins. The abundance of dihydrofolate reductase (DHFR) was statistically significantly increased in RA-patient biopsies compared with controls and correlated with the administered dosage of methotrexate (MTX), the most frequently prescribed immunosuppressive drug for RA. Additionally, our data suggest that treatment with Leflunomide, a common alternative to MTX, increases DHFR. The findings were supported by immunohistochemistry with confocal microscopy, which furthermore demonstrated that DHFR was located in the cytosol of the intestinal epithelial and interstitial cells. Finally, we identified 223 citrullinated peptides from 121 proteins. Three of the peptides were unique to RA. The list of citrullinated proteins was enriched in extracellular and membrane proteins and included known targets of anticitrullinated protein antibodies (ACPAs). Our findings support that the colon mucosa could trigger the production of ACPAs, which could contribute to the onset of RA. The MS data have been deposited to ProteomeXchange with identifiers PXD001608 and PXD003082.

Neutrophil Extracellular Traps in Ulcerative Colitis: A Proteome Analysis of Intestinal Biopsies.

BACKGROUND: The etiology of the inflammatory bowel diseases, including ulcerative colitis (UC), remains incompletely explained. We hypothesized that an analysis of the UC colon proteome could reveal novel insights into the disease etiology. METHODS: Mucosal colon biopsies were taken by endoscopy from noninflamed tissue of 10 patients with UC and 10 controls. The biopsies were either snap-frozen for protein analysis or prepared for histology. The protein content of the biopsies was characterized by high-throughput gel-free quantitative proteomics, and biopsy histology was analyzed by light microscopy and confocal microscopy. RESULTS: We identified and quantified 5711 different proteins with proteomics. The abundance of the proteins calprotectin and lactotransferrin in the tissue correlated with the degree of tissue inflammation as determined by histology. However, fecal calprotectin did not correlate. Forty-six proteins were measured with a statistically significant differences in abundances between the UC colon tissue and controls. Eleven of the proteins with increased abundances in the UC biopsies were associated with neutrophils and neutrophil extracellular traps. The findings were validated by microscopy, where an increased abundance of neutrophils and the presence of neutrophil extracellular traps by extracellular DNA present in the UC colon tissue were confirmed. CONCLUSIONS: Neutrophils, induced neutrophil extracellular traps, and several proteins that play a part in innate immunity are all increased in abundance in the morphologically normal colon mucosa from patients with UC. The increased abundance of these antimicrobial compounds points to the stimulation of the innate immune system in the etiology of UC.

[Microscopic colitis is a common cause of chronic diarrhoea]. / Mikroskopisk kolitis er en hyppig årsag til kronisk diarré.

Microscopic colitis (MC) is a common cause of chronic, non-bloody diarrhoea in the elderly population. In Denmark the incidence has been rising for the last decades. Sufficient biopsy material from colon mucosa is essential for the diagnosis. Treatment is important to improve the patient's quality of life, which is significantly impaired in active MC. This paper reviews newly published data regarding epidemiology, diagnostic criteria and a new European treatment guideline and also includes updates on ongoing and future studies in MC.