Project description:Background: CrohnM-bM-^@M-^Ys disease is presently an incurable inflammatory bowel disease. Fistulae are extensions of the intestinal tract that may form connections with other organs. These are a common complication of CrohnM-bM-^@M-^Ys disease affecting up to 50% of patients with the most common including perianal and rectovaginal fistulae. The dysregulated growth observed in fistulae shares several major characteristics seen in the development of tumours. These similarities include epithelial-to-mesenchymal transition (EMT), invasive cell growth, increased extracellular matrix production and remodelling, up-regulated local expression of growth factors such as IGF-1 and the down-regulation of apoptosis pathways. Although several susceptibility loci have been described within CrohnM-bM-^@M-^Ys disease there is no individual gene or mutation that identifies susceptibility or the subsequent formation of fistulae within all people. Copy-number variation (CNV) is one mechanism that may explain much of this genetic complexity. CNV may be caused by a variety of mechanisms such as cycles of chromosomal breakage/fusion/bridging that are typical within chronically inflamed tissue. Interestingly CNV shows locus-specific mutation rates between individuals higher than that of SNPs and has been associated with complex Mendelian traits including disease susceptibility. In this current study we performed array comparative genomic hybridisation (aCGH) analysis of active fistulae resected from patients as part of a previous surgical intervention. As the control for comparison we employed tissue taken from the same patient within the same surgery at an uninvolved site of the gastrointestinal tract. This matched control was employed to better investigate CNV specific to the fistula tissue of each individual avoiding complications associated with the large number of CNV present within the healthy population. Major question addressed by the work: What are the differences in genetic copy-number within localised intestinal fistula tissue of individuals with CrohnM-bM-^@M-^Ys disease compared to healthy intestinal tissue from the same individual? Samples were selected from patients presenting with CrohnM-bM-^@M-^Ys Disease fistulae at Eastern Health Department of Gastroenterology and Hepatology (Arnold Street, Box Hill, Victoria, Australia). The 8 samples used in this study were formalin-fixed paraffin-embedded (FFPE) specimens following a surgical intervention to remove fistula tissue. To focus on changes within the individual patient we used tissue taken from the same surgery at an uninvolved region of the intestine as the matched control for CNV analysis.

Project description:Background: Crohn’s disease is presently an incurable inflammatory bowel disease. Fistulae are extensions of the intestinal tract that may form connections with other organs. These are a common complication of Crohn’s disease affecting up to 50% of patients with the most common including perianal and rectovaginal fistulae. The dysregulated growth observed in fistulae shares several major characteristics seen in the development of tumours. These similarities include epithelial-to-mesenchymal transition (EMT), invasive cell growth, increased extracellular matrix production and remodelling, up-regulated local expression of growth factors such as IGF-1 and the down-regulation of apoptosis pathways. Although several susceptibility loci have been described within Crohn’s disease there is no individual gene or mutation that identifies susceptibility or the subsequent formation of fistulae within all people. Copy-number variation (CNV) is one mechanism that may explain much of this genetic complexity. CNV may be caused by a variety of mechanisms such as cycles of chromosomal breakage/fusion/bridging that are typical within chronically inflamed tissue. Interestingly CNV shows locus-specific mutation rates between individuals higher than that of SNPs and has been associated with complex Mendelian traits including disease susceptibility. In this current study we performed array comparative genomic hybridisation (aCGH) analysis of active fistulae resected from patients as part of a previous surgical intervention. As the control for comparison we employed tissue taken from the same patient within the same surgery at an uninvolved site of the gastrointestinal tract. This matched control was employed to better investigate CNV specific to the fistula tissue of each individual avoiding complications associated with the large number of CNV present within the healthy population. Major question addressed by the work: What are the differences in genetic copy-number within localised intestinal fistula tissue of individuals with Crohn’s disease compared to healthy intestinal tissue from the same individual?

Project description:Background: Although clinical outcome of arteriovenous fistula (AVF) as a preferred vascular access for hemodialysis has been inadequate, biological mechanisms of AVF maturation and failure is still poorly understood. Since our mouse AVF model recapitulates human AVF maturation and partial failure, we hypothesized that high throughput RNA sequencing (RNA-seq) analysis would identify early changes in gene expression that might predict AVF maturation and failure. Method: Aortocaval fistula creation (AVF group) or sham operation (sham group) was performed with C57BL/6 mice (10 wk). Ultrasound was performed to confirm the AVF patency and to measure hemodynamics. Venous limbs were collected on postoperative day 7 and total RNA was extracted. After Poly-A mRNA libraries were constructed, RNA-seq was performed. Differentially expressed genes (DEG) were identified, and subsequent enrichment analyses of gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways were performed with bioinformatics techniques. Results: 1057 DEG were identified between the AVF and sham groups. Genes in metabolic pathways were significantly downregulated in the AVF. Since gene expression patterns among the AVF group were significantly heterogenous, the AVF group was divided into 2 groups (‘normal’ AVF group; nAVF and ‘outliers’ group; OUT), and subgroup analyses were performed. Although physiological data of body weight change and hemodynamics were not different between the nAVF and OUT groups, 413 DEG were identified between them. Enrichment analyses showed significant overrepresentation of metabolism, immunity, and coagulation in the OUT group. Comparing the nAVF group with the sham group, 403 DEG were identified. Enrichment analyses showed increase of gene expression related to cell cycle, extracellular matrix, and immunity. Comparing these results with previously published data, the gene expression patterns of the nAVF group was consistent with AVF maturation and adaptive remodeling, whereas the OUT group showed attenuated difference, suggesting the heterogeneity of the AVF group reflects early gene expression changes in the process of AVF maturation and failure. Significant sex differences were not observed in the AVF group. Conclusions: A small subset of AVF undergoes aberrant biological processes in the early phase including diminished ECM remodeling, activated coagulation and upregulated metabolism, that could lead to fistula failure. Detection of these processes might be a viable translational strategy to predict fistula failure and reduce patient morbidity.

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Eguchipsammia fistula

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