Unknown,Transcriptomics,Genomics,Proteomics

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Expression data from peritoneal biopsies of patients with encapsulating peritoneal sclerosis, patients undergoing first implantation of a peritoneal dialysis catheter, and patients undergoing abdominal surgery for non-peritoneal conditions

ABSTRACT: Expression data from peritoneal biopsies of patients with encapsulating peritoneal sclerosis (EPS), patients undergoing first implantation of a peritoneal dialysis catheter (PD), and patients undergoing abdominal surgery for non-peritoneal conditions (controls) We used microarrays to determine the transcriptional profiles of peritoneal membrane in patients with encapsulating peritoneal sclerosis (EPS), patients undergoing first insertion of a peritoneal dialysis cathetier (PD), and uremic patients without history of PD or EPS, undergoing abdominal surgery for non-peritoneal problems (CON) Encapsulating peritoneal sclerosis (EPS) is a devastating complication of peritoneal dialysis (PD), characterized by marked inflammation and severe fibrosis of the peritoneum, and associated with high morbidity and mortality. EPS can occur years after termination of PD and, in severe cases, leads to intestinal obstruction and ileus requiring surgical intervention. Despite ongoing research, the pathogenesis of EPS remains unclear. We performed a global transcriptome analysis of peritoneal tissue specimens from EPS patients, PD patients without EPS, and uremic patients without history of PD or EPS (Uremic). Unsupervised and supervised bioinformatics analysis revealed distinct transcriptional patterns that discriminated these three clinical groups. The analysis identified a signature of 219 genes expressed differentially in EPS as compared to PD and Uremic groups. Canonical pathway analysis of differentially expressed genes showed enrichment in several pathways, including antigen presentation, dendritic cell maturation, B cell development, chemokine signaling and humoral and cellular immunity (P value <0.05). Further interactive network analysis depicted effects of EPS-associated genes on networks linked to inflammation, immunological response, and cell proliferation. Gene expression changes were confirmed by qRT-PCR for a subset of the differentially expressed genes. EPS patient tissues exhibited elevated expression of genes encoding sulfatase1, thrombospondin 1, fibronectin 1 and alpha smooth muscle actin, among many others, while in EPS and PD tissues mRNAs encoding leptin and retinol-binding protein 4 were markedly down-regulated, compared to Uremic group patients. Immunolocalization of Collagen 1 alpha 1 revealed that Col1a1 protein was predominantly expressed in the submesothelial compact zone of EPS patient peritoneal samples, whereas PD patient peritoneal samples exhibited homogenous Col1a1 staining throughout the tissue samples. The results are compatible with the hypothesis that encapsulating peritoneal sclerosis is a distinct pathological process from the simple peritoneal fibrosis that accompanies all PD treatment. Total RNA was isolated from frozen peritoneal biopsy specimens obtained at time of surgery. RNA was hybridized to Affymetrix arrays, and analyzed. Select transcripts were subjected to validation by rt-pcr and by immunodetection.

ORGANISM(S): Homo sapiens

SUBMITTER: Manoj Bhasin

PROVIDER: E-GEOD-62928 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Project description:Expression data from peritoneal biopsies of patients with encapsulating peritoneal sclerosis (EPS), patients undergoing first implantation of a peritoneal dialysis catheter (PD), and patients undergoing abdominal surgery for non-peritoneal conditions (controls) We used microarrays to determine the transcriptional profiles of peritoneal membrane in patients with encapsulating peritoneal sclerosis (EPS), patients undergoing first insertion of a peritoneal dialysis cathetier (PD), and uremic patients without history of PD or EPS, undergoing abdominal surgery for non-peritoneal problems (CON) Encapsulating peritoneal sclerosis (EPS) is a devastating complication of peritoneal dialysis (PD), characterized by marked inflammation and severe fibrosis of the peritoneum, and associated with high morbidity and mortality. EPS can occur years after termination of PD and, in severe cases, leads to intestinal obstruction and ileus requiring surgical intervention. Despite ongoing research, the pathogenesis of EPS remains unclear. We performed a global transcriptome analysis of peritoneal tissue specimens from EPS patients, PD patients without EPS, and uremic patients without history of PD or EPS (Uremic). Unsupervised and supervised bioinformatics analysis revealed distinct transcriptional patterns that discriminated these three clinical groups. The analysis identified a signature of 219 genes expressed differentially in EPS as compared to PD and Uremic groups. Canonical pathway analysis of differentially expressed genes showed enrichment in several pathways, including antigen presentation, dendritic cell maturation, B cell development, chemokine signaling and humoral and cellular immunity (P value <0.05). Further interactive network analysis depicted effects of EPS-associated genes on networks linked to inflammation, immunological response, and cell proliferation. Gene expression changes were confirmed by qRT-PCR for a subset of the differentially expressed genes. EPS patient tissues exhibited elevated expression of genes encoding sulfatase1, thrombospondin 1, fibronectin 1 and alpha smooth muscle actin, among many others, while in EPS and PD tissues mRNAs encoding leptin and retinol-binding protein 4 were markedly down-regulated, compared to Uremic group patients. Immunolocalization of Collagen 1 alpha 1 revealed that Col1a1 protein was predominantly expressed in the submesothelial compact zone of EPS patient peritoneal samples, whereas PD patient peritoneal samples exhibited homogenous Col1a1 staining throughout the tissue samples. The results are compatible with the hypothesis that encapsulating peritoneal sclerosis is a distinct pathological process from the simple peritoneal fibrosis that accompanies all PD treatment.

Project description:Peritoneal dialysis (PD) is the worldwide recognized preferred dialysis treatment for children affected by end-stage kidney disease (ESKD). However, due to the unphysiological composition of PD fluids, the peritoneal membrane (PM) of these patients may undergo structural and functional alterations, which may cause fibrosis. Several factors may accelerate this process and primary kidney disease may have a causative role. In particular, patients affected by corticoresistant primary focal segmental glomerulosclerosis), a rare glomerular disease leading to nephrotic syndrome and ESKD, seem more prone to develop peritoneal fibrosis. The mechanism causing this predisposition is still unrecognized. To better define this condition, we carried out, for the first time, a new comprehensive comparative proteomic mass spectrometry analysis of mesothelial exosomes from peritoneal dialysis effluent (PDE) of 6 pediatric patients with focal segmental glomerular sclerosis (FSGS) versus 6 patients affected by other primary renal diseases (No FSGS). Our omic study demonstrated that, despite the high overlap in the protein milieu between the two study groups, machine learning allowed a complete distinction of the whole proteomic exosome mesothelial content of FSGS versus No FSGS (with 100% accuracy). Out of the 2490 identified proteins, 40% (995) were involved in epithelial-mesenchymal transition (EMT)/fibrosis and in the transforming growth factor-β pathway. Additionally, the Weight Gene Co-expression Network Analysis algorithm identified that some of the discriminative proteins (TIMP1, CTHRC1, SPARC, CHMP4B, COL5A2, ANXA13, FNC2 and CENP-E) were also highly correlated to PD vintage, fibrosis, EMT and non-neoplastic PM disease. All together our data demonstrated that mesothelial cells of FSGS patients are more prone to activate a pro-fibrotic machinery with exosomes having a primary role in this process. Moreover, they indicated that identified FSGS-associated elements in mesothelial exosome protein could be employed as potential new biomarkers of mesothelial integrity. Finally, our results highlighted that in FSGS patients particular attention should be paid to use more biocompatible dialysis solution, reduce the length of time on PD and personalize PD regimens to minimize the risk of rapid loss of PM function or development of encapsulating peritoneal sclerosis.

Project description:Loss of ultrafiltration capacity in peritoneal dialysis (PD) patients is often associated with peritoneal vascular changes, manifest as diabetes-like vasculopathy and angiogenesis. The endothelial monolayer lining the vessel lumen controls vessel barrier function and thereby influences peritoneal substrate transport and ultrafiltration. In this study, we first characterized the response to conventional PD fluids of endothelial cells isolated from peritoneal biopsies of children undergoing PD. 9 omental biopsies from the pediatric biopsy biobank (mean age 5.7 years) were included in this study. PD patients were treated with conventional PD fluid (mean PD vintage 12.5 months). Age-matched controls (n=5) with normal renal function undergoing elective surgery were also included. In patients on PD, the biopsy sampling site was at least 5 cm away from the PD catheter entry site. Written informed consent was obtained from parents, and from patients as appropriate. The study was performed according to the Declaration of Helsinki and registered at www.clinicaltrials.gov (NCT01893710). The study was part of the International Pediatric Dialysis Network (IPDN; www.pedpd.org). Patients with a BMI of >35 kg/m2 and with chronic inflammatory diseases were excluded. Specimens obtained during surgery were instantaneously frozen with liquid nitrogen and stored at -80°C. Arterioles macroscopically located within fat tissue and microscopically at least 1mm distant from the peritoneal surface were micro-dissected. Elastica van Gieson stainings of the arteriolar elastic lamina were used as templates for microdissection of arterioles from cresol violet–stained neighboring sections. 100 µm thick tissue slices were cut with a cryotome and 30 deep-frozen arteriolar rings per patient were micro-dissected using a stereo microscope and a microneedle. Arteriolar rings were lysed in 100 µl lysis buffer (30 mM Tris, pH 8.5, 7M urea, 2M thiourea, 4% 3-[(3-Cholamidopropyl) dimethylammonio]-1-propanesulfonate (CHAPS), 1 mM EDTA, 1 tablet of Complete Protease Inhibitor (Roche, Basel, Switzerland) and 1 tablet of phosphatase inhibitor (PhosSTOP, Roche) per 100 ml). The resulting lysates were stored at -80°C until further processing. Total protein concentration was determined with the 2D-Quant kit (GE). Quality control and verification of protein concentrations was performed by SDS-PAGE. We investigated the molecular mechanisms of endothelial cell pathology during in vivo and in vitro PD fluid exposure by proteomic and bioinformatic analysis of the endothelial cell response to hyperglycemic stress, integrating current understanding of PD-related cellular injury and stress responses (Bender et al., Nephrol Dial Transplant, 2011, doi:10.1093/ndt/gfq484; Kratochwill et al., BioMed research international, 2015, doi:10.1155/2015/628158; Kratochwill et al., J Proteome Res, 2009, doi:10.1021/pr800916s; Lechner et al., J Proteome Res, 2010, doi:10.1021/pr9011574).

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Expression data from peritoneal biopsies of patients with encapsulating peritoneal sclerosis, patients undergoing first implantation of a peritoneal dialysis catheter, and patients undergoing abdominal surgery for non-peritoneal conditions

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