Project description:Restorative proctocolectomy with ileal pouch-anal anastomosis is a surgical procedure in patients with ulcerative colitis refractory to medical therapies. Pouchitis, the most common complication, is inflammation of the pouch of unknown etiology. To define how the intestinal immune system is distinctly organized in response to inflammation and to develop mechanistic hypotheses of pouchitis, we analyzed tissues from patients with and without pouchitis and from patients with ulcerative colitis using single-cell RNA sequencing. We examined pouch lamina propria CD45+ hematopoietic cells from intestinal tissues of ulcerative colitis patients with (n=15) and without an ileal pouch-anal anastomosis (n=11). Further in silico meta-analysis was performed to generate transcriptional interaction networks and identify drug targets for patients with inflamed pouches. We identified a population of IL1B+ antimicrobial macrophages and FOXP3+/BATF+ T cells that are expanded in inflamed tissues, which we further validated in other single cell RNA-seq datasets from IBD patients. Cell type specific markers obtained from single-cell RNA-sequencing was used to infer representation from bulk RNA sequencing datasets, which further implicated antimicrobial macrophages expressing IL1B with S100A8/A9 calprotectin as being associated with inflammation, and Bacteroidiales and Clostridiales bacterial taxa. We found that non-responsiveness to anti-integrin biologic therapies in ulcerative colitis patients was associated with the signature of this antimicrobial macrophage population in a subset of patients. This study identified conserved and distinct features of intestinal inflammation between parts of the small and large intestine undergoing similar inflammation conditions. Specifically, we relate inflammation of the pouch, a surgically constructed organ, to other inflammatory contexts throughout the gastrointestinal tract.
Project description:Pouchitis is a common complication for ulcerative colitis (UC) patients with ileal pouch-anal anastomosis (IPAA) surgery. Similarly to IBD, both innate host factors such as genetics, and environmental stimuli including the tissue-associated microbiome have been implicated in the pathogenesis. In this study, we make use of the IPAA model of inflammatory bowel disease (IBD) to carry out a study associating mucosal host gene expression with the microbiome and corresponding clinical outcomes. In order to determine how host gene expression might influence, or be influenced by the tissue associated microbiome, we analyzed 205 IPAA patients with biopsies collected from the pouch and afferent limb for host transcriptomics and 16S rDNA gene sequencing. Metadata included antibiotic use, inflammation score, and clinical classification. To achieve power for a genome-wide microbiome-transcriptome association study, we used principal component analysis to reduce OTUs and host transcripts to eigengenes and eigenclades explaining 50% of observed variance. These were subsequently tested for significant covariation with one another and/or outcome using multivariate linear modeling.
Project description:Gut dysbiosis and host genetics are implicated as causative factors in inflammatory bowel disease, yet mechanistic insights are lacking. Longitudinal analysis of ulcerative colitis patients following total colectomy with ileal anal anastomosis (IPAA) where >50% develop pouchitis, offers a unique setting to examine cause vs. effect. To recapitulate human IPAA, we employed a mouse model of surgically-created blind self-filling (SFL) and self-emptying (SEL) ileal loops. SFL exhibit fecal stasis due to directional peristalsis motility oriented towards away from the loop end, whereas SEL remain empty. In wild type mice, SFL, but not SEL, develop pouch-like microbial communities without accompanying active inflammation. However, in genetically susceptible IL-10-/- deficient mice, SFL, but not SEL, exhibit severe inflammation and mucosal transcriptomes resembling human pouchitis. Germ-free IL10-/- mice conventionalized with wild type SFL, but not SEL, microbiota, develop severe colitis. These data demonstrate an essential role for fecal stasis, gut dysbiosis, and genetic susceptibility and offer insights into human pouchitis and ulcerative colitis.
Project description:Total proctocolectomy with ileal pouch anal anastomosis (IPAA) is the standard treatment for patients with severe treatment resistant ulcerative colitis (UC). Despite significant improvements in patient outcomes, up to 50% of patients will develop inflammation of the pouch (pouchitis) within 1-2 years following surgery. The pathogenesis of pouchitis is not well understood. Functionalization of UC pouches is associated with histological changes, whether these reflect changes in cellular identity and metaplasia remains unclear. To address this question, we generated cellular atlases of single-cell transcriptomes and accessible chromatin to assess the cellular composition, transcriptomic and epigenetic profiles in UC pouches.
Project description:Total proctocolectomy with ileal pouch anal anastomosis (IPAA) is the standard treatment for patients with severe treatment resistant ulcerative colitis (UC). Despite significant improvements in patient outcomes, up to 50% of patients will develop inflammation of the pouch (pouchitis) within 1-2 years following surgery. The pathogenesis of pouchitis is not well understood. Functionalization of UC pouches is associated with histological changes, whether these reflect changes in cellular identity and metaplasia remains unclear. To address this question, we generated cellular atlases of single-cell transcriptomes and accessible chromatin to assess the cellular composition, transcriptomic and epigenetic profiles in UC pouches.
Project description:The pathophysiology of Crohn’s-like disease of the pouch (CDP) that develops after restorative proctocolectomy with ileal pouch-anal anastomosis (IPAA) for ulcerative colitis (UC) is unknown. We examined mucosal cells from patients with and without CDP using single cell analyses.
Project description:Gut dysbiosis and host genetics are implicated as causative factors in inflammatory bowel disease, yet mechanistic insights are lacking. Longitudinal analysis of ulcerative colitis patients following total colectomy with ileal anal anastomosis (IPAA) where >50% develop pouchitis, offers a unique setting to examine cause vs. effect. To recapitulate human IPAA, we employed a mouse model of surgically-created blind self-filling (SFL) and self-emptying (SEL) ileal loops. SFL exhibit fecal stasis due to directional peristalsis motility oriented towards away from the loop end, whereas SEL remain empty. In wild type mice, SFL, but not SEL, develop pouch-like microbial communities without accompanying active inflammation. However, in genetically susceptible IL-10-/- deficient mice, SFL, but not SEL, exhibit severe inflammation and mucosal transcriptomes resembling human pouchitis. Germ-free IL10-/- mice conventionalized with wild type SFL, but not SEL, microbiota, develop severe colitis. These data demonstrate an essential role for fecal stasis, gut dysbiosis, and genetic susceptibility and offer insights into human pouchitis and ulcerative colitis. All animal protocols were approved by IACUC at the University of Chicago. All animals were C57Bl/6 mice that were bred and housed under standard 12:12 light/dark conditions at the University of Chicago. Female mice aged 6-8 weeks were fed ad libitum gel diet 76A (Cat# 72-07-5022, Clear H20, Portland, ME) for 5-days prior to surgery to prevent obstruction at the anastomosis. Animals were anesthetized with ketamine/xylazine. Aseptic surgery was performed to resect 2.5cm of ileum 3cm proximal to the ileal-cecal value with anastomosis to the ileum using 8-0 suture (Figure 1a). The abdominal wall was closed with interrupted 4-0 silk suture and skin was closed with staples. Analgesics (betanorphine mg/kg BW) were provided post-operatively. After 5 weeks, mice were humanely euthanized. Intestinal loops were collected for RNA, protein, and histology. Loop, sham ileum, and sham colon contents were collected and snap frozen at −80°C for microbiota analysis. Human biopsies and stool samples were obtained under IRB approval and privacy protocols were followed. Our initial work demonstrated up regulation of TLR4 signaling in the mucosa of self-filling ileal loops. We hypothesized that TLR4 may be in-part responsible for mediating the metaplasia and inflammatory responses observed. Therefore, TLR4 KO mice were used to test this hypothesis and subsequently demonstrated attenuated responses in these parameters.
Project description:The aim of this study is to identify early pathogenic changes in ileal gene expression that precede the development of macroscopic disease in inflammatory bowel diseases (IBDs). We focused on two IBD phenotypes that were unlikely to overlap: 1) ileal Crohn’s disease (CD) patients undergoing initial ileocolic resection of diseased ileum; and 2) ulcerative colitis (UC) patients undergoing total colectomy. The Control patients were those patients without IBD undergoing initial right hemicolectomy or total colectomy. In order to identify early pathogenic changes in the human ileum in inflammatory bowel diseases, we analyzed 99 two-color whole human genome expression profiles (Agilent 4410A) of a test human ileal cRNA probe vs. a common reference human ileal RNA from a Control patient (N17). A minimum of four biopsies were taken from the macroscopically disease-unaffected proximal ileal margin of freshly resected specimens from 47 ileal Crohn's disease patients undergoing initial ileocolic resection, 27 ulcerative colitis patients undergoing total colectomy and 25 Control patients undergoing either right hemicolectomy or total colectomy. The test and common reference probes were synthesized using the Agilent Low Input Linear Amplification Kit. Hybridization was carried out in DNA hybridization chambers, washed and scanned on an Axon GenePix 4000B scanner. The preprocessing, filtering and normalization of the array data was carried out using the R package LIMMA.
Project description:The aim of this study is to identify early pathogenic changes in ileal gene expression that precede the development of macroscopic disease in inflammatory bowel diseases (IBDs). We focused on two IBD phenotypes that were unlikely to overlap: 1) ileal Crohn’s disease (CD) patients undergoing initial ileocolic resection of diseased ileum; and 2) ulcerative colitis (UC) patients undergoing total colectomy. The Control patients were those patients without IBD undergoing initial right hemicolectomy or total colectomy.
Project description:<p>This study involved evaluation of the tissue associated microbiome of the ileal pouch following surgery for ulcerative colitis (UC) or familial adenomatous polyposis (FAP). Individuals were recruited, with biopsies taken from the ileal pouch and the pre-pouch ileum, microbial DNA was extracted and sequenced using 454 pyrosequencing. Total bacterial community structure and abundance were evaluated to determine which changes were characteristic of inflammatory phenotypes including pouchitis (inflammation of the ileal pouch) and a Crohn's disease-like phenotype.</p>