Characterization of Epithelial-to-Mesenchymal Transition of Mesothelial Cells in a Mouse Model of Chronic Peritoneal Exposure to High Glucose Dialysate

Abstract

Animal models of peritoneal dialysis fluid (PDF) exposure are key tools in the study of mechanisms involved in alterations of the peritoneal membrane and in the design of therapies. We recently developed a mouse model of chronic peritoneal exposure to high glucose dialysate. Herein, we make a sequential analysis of the effects of glucose-based PDF on mouse peritoneal membrane and on mesothelium. We demonstrate that chronic exposure to PDF induces thickness and fibrosis of the peritoneal membrane in a time-dependent manner. We also show that mesothelial cells progressively detach and lose cytokeratin expression. In addition, we demonstrate that some mesothelial cells invade the submesothelial space, where they appear as cytokeratin- and alpha-smooth muscle actin-positive cells. These findings demonstrate that epithelial-to-mesenchymal transition (EMT) of mesothelial cells takes place in mouse peritoneum exposed to PDF, validating this model for the study of effects of drugs on the EMT process as a therapy for peritoneal deterioration.

Peritoneal Membrane Injury and Peritoneal Dialysis

“…Although we have provided substantial evidence for TGFB mediated peritoneal EMT using standard dual labeling studies along with electron microscopy [29], and this has been supported by studies from other groups using different stimuli [26,30,34,35], EMT as a prime mechanism of fibrosis has come under question recently. For example, EMT of renal tubular epithelial cells was once felt to be a major source of interstitial myofibroblasts and renal fibrosis [36].…”

“…In the setting of peritoneal fibrosis, EMT has been experimentally induced by a number of agents associated with PD including high glucose concentration [26], glucose degradation products (GDP) [27], and peritoneal inflammation [28]. We have identified TGFB as a direct mediator of EMT in the peritoneum [29].…”

AKT regulation of mesothelial-to-mesenchymal transition in peritoneal dialysis is modulated by smurf2 and deubiquitinating enzyme USP4

“…The mice were housed in standard conditions and with free access to food and water. A Peritoneal dialysis mouse model was established according to the report by Aroeira LS et al , as previously described [ 48 ]. Briefly, to prevent obstruction and proper drainage of fluid, catheters containing ten holes within 1 cm from the tip were used.…”

The Mechanism of Peritoneal Fibrosis in Peritoneal Dialysis

“…PMCs express epithelial markers such as E-cadherin, cytokeratin and intercellular adhesion molecule 1 (ICAM-1). During the process of EMT, these epithelial markers are downregulated and mesenchymal markers such as α-smooth muscle actin, vimentin and fibronectin are upregulated, leading to a change into mesenchymal-like PMCs [7][8][9][10][11]. The expression of type I collagen and the migratory capacity are enhanced in these transformed PMCs [9,12].…”