Animal Model Of Peritoneal Dialysis Research Articles

A Mice Model of Chlorhexidine Gluconate-Induced Peritoneal Damage.

Peritoneal fibrosis is an important complication of peritoneal dialysis (PD). To investigate and address this problem, an appropriate animal model of PD is required. The present protocol establishes a chlorhexidine gluconate (CG) induced peritoneal fibrosis model that mimics the condition of a patient with PD. Peritoneal fibrosis was induced by intraperitoneal injection of 0.1% of CG in 15% ethanol for 3 weeks (administered every other day), for a total of nine times in male C57BL/6 mice. Peritoneal functional tests were then performed on day 22. After the mice were sacrificed, the parietal peritoneum of the abdominal wall and the visceral peritoneum of the liver were harvested. They were thicker and more fibrotic when analyzed microscopically after Masson's trichrome staining. The ultrafiltration rate decreased, and glucose mass transport indicated a CG-induced increase in peritoneal permeability. The PD model thus established may have applications in improving PD technology, dialysis efficacy, and prolonging patient survival.

Metformin ameliorates the Phenotype Transition of Peritoneal Mesothelial Cells and Peritoneal Fibrosis via a modulation of Oxidative Stress

Phenotype transition of peritoneum is an early mechanism of peritoneal fibrosis. Metformin, 5′-adenosine monophosphate-activated protein kinase (AMPK) activator, has recently received a new attention due to its preventive effect on organ fibrosis and cancer metastasis by inhibiting epithelial-to-mesenchymal transition (EMT). We investigated the effect of metformin on EMT of human peritoneal mesothelial cells (HPMC) and animal model of peritoneal dialysis (PD). TGF-β1-induced EMT in HPMC was ameliorated by metformin. Metformin alleviated NAPDH oxidase- and mitochondria-mediated ROS production with an increase in superoxide dismutase (SOD) activity and SOD2 expression. Metformin inhibited the activation of Smad2/3 and MAPK, GSK-3β phosphorylation, nuclear translocalization of β-catenin and Snail in HPMCs. Effect of metformin on TGF-β1-induced EMT was ameliorated by either AMPK inhibitor or AMPK gene silencing. Another AMPK agonist, 5-amino-1-β-D-ribofuranosyl-imidazole-4-carboxamide partially blocked TGF-β1-induced EMT. In animal model of PD, intraperitoneal metformin decreased the peritoneal thickness and EMT with an increase in ratio of reduced to oxidized glutathione and the expression of SOD whereas it decreased the expression of nitrotyrosine and 8-hydroxy-2′-deoxyguanosine. Therefore, a modulation of AMPK in peritoneum can be a novel tool to prevent peritoneal fibrosis by providing a favorable oxidant/anti-oxidant milieu in peritoneal cavity and ameliorating phenotype transition of peritoneal mesothelial cells.

Surgical Technique Using An Improvised Peritoneal Catheter In An Experimental Non-Uremic Rabbit Model Of Peritoneal Dialysis

Abstract Experimental models have strongly contributed to the comprehension of the processes of peritoneal damage that take place during peritoneal dialysis treatment in human patients. A variety of peritoneal dialysis models have been developed, mostly using rats and rabbits. In this study we present the successful development of a custom-made improvised peritoneal catheter for an experimental non-uremic rabbit model of peritoneal dialysis. A detailed description of the surgical technique of peritoneal catheter implantation, care and removal is provided. This innovative approach to constructing a peritoneal catheter in rabbit animal model of peritoneal dialysis is easy, reproducible and inexpensive. The surgical technique applied provided adequate tissue samples for both light and electron microscopy.

Twist Contributes to Proliferation and Epithelial-to-Mesenchymal Transition–Induced Fibrosis by Regulating YB-1 in Human Peritoneal Mesothelial Cells

Twist is overexpressed in high glucose (HG) damage of human peritoneal mesothelial cells (HPMCs) invitro. Herein, we further identified its precise function related to fibrosis of peritoneal membranes (PMs). The overexpression and activation of Twist and YB-1 (official name, YBX1) and a transformed fibroblastic phenotype of HPMCs were found to be positively related to epithelial-mesenchymal transition progress and PM fibrosis exvivo in 93 patients who underwent continuous ambulatory peritoneal dialysis (PD), and also in HG-induced immortal HPMCs and an animal model of PD. Evidence from chromatin immunoprecipitation and luciferase reporter assays supported that YBX1 is transcriptionally regulated by the direct binding of Twist to E-box. Overexpression of Twist and YB-1 led to an increase in epithelial-mesenchymal transition, proliferation, and cell cycle progress of HPMCs, which might contribute to PM fibrosis. In contrast, the silencing of Twist or YB-1 inhibited HG-induced growth and cell cycle progression of HPMCs; this led to a down-regulation in the expression of cyclin Ds and cyclin-dependent kinases, finally inhibiting PM fibrosis. Twist contributes to PM fibrosis during PD treatment, mainly through regulation of YB-1.

The monocyte chemoattractant protein-1 (MCP-1)/CCR2 system is involved in peritoneal dialysis-related epithelial–mesenchymal transition of peritoneal mesothelial cells

Epithelial–mesenchymal transition (EMT) of peritoneal mesothelial cells (PMCs) has a role in the process of peritoneal fibrosis (PF), a serious complication in peritoneal dialysis (PD) patients. Even though monocyte chemoattractant protein-1 (MCP-1) was demonstrated to directly increase extracellular matrix (ECM) synthesis, the role of the MCP-1/CCR2 system in PD-related EMT and ECM synthesis in cultured human PMCs (HPMCs) and in an animal model of PD has never been elucidated. In vitro, HPMCs were exposed to 5.6 mM glucose (NG), NG+MCP-1 (10 ng/ml) (NG+MCP-1), or 100 mM glucose (HG) with or without CCR2 inhibitor (RS102895) (CCR2i) or a dominant-negative mutant MCP-1-expressing lentivirus (LV-mMCP-1). In vivo, PD catheters were inserted into 60 Sprague-Dawley rats, and saline (Control, C) (N=30) or 4.25% PD solution (PD) (N=30) was infused for 4 weeks. Twenty rats from each group were treated with empty LV or LV-mMCP-1 intraperitoneally. Snail, E-cadherin, α-smooth muscle actin (α-SMA), and fibronectin protein expression in HPMCs and the peritoneum was evaluated by western blot analysis. Compared with NG cells, Snail, α-SMA, and fibronectin expression was significantly increased, while E-cadherin expression was significantly decreased in HPMCs exposed to HG and NG+MCP-1, and these changes were significantly abrogated by CCR2i (P<0.05). In addition, MCP-1-induced EMT was significantly attenuated by anti-TGF-β1 antibody. In PD rats, Snail and fibronectin expression was significantly increased in the peritoneum, whereas the ratios of E-cadherin/α-SMA protein expression were significantly decreased (P<0.05). The thickness of the peritoneum and the intensity of Masson's trichrome staining in the peritoneum were also significantly higher in PD rats than in C rats (P<0.05). These changes in PD rats were significantly abrogated by LV-mMCP-1. These findings suggest that the MCP-1/CCR2 system is directly involved in PD-related EMT and ECM synthesis and that this is mediated, at least in part, via TGF-β1.

HGF and BMP-7 Ameliorate High Glucose–Induced Epithelial-to-Mesenchymal Transition of Peritoneal Mesothelium

Over time, peritoneal dialysis results in functional and structural alterations of the peritoneal membrane, but the underlying mechanisms and whether these changes are reversible are not completely understood. Here, we studied the effects of high levels of glucose, which are found in the dialysate, on human peritoneal mesothelial cells (HPMCs). We found that high concentrations of glucose induced epithelial-to-mesenchymal transition (EMT) of HPMC, suggested by decreased expression of E-cadherin and increased expression of alpha-smooth muscle actin, fibronectin, and type I collagen and by increased cell migration. Normalization of glucose concentration on day 2 reversed the phenotypic transformation, but the changes were irreversible after 7 d of stimulation with high glucose. In addition, exposure of HPMC to high glucose resulted in a decreased expression of the antifibrotic cytokines, hepatocyte growth factor (HGF) and bone morphogenic protein 7 (BMP-7). Exogenous treatment with HGF resulted in a dosage-dependent prevention of high glucose-induced EMT. Both BMP-7 peptide and gene transfection with an adenoviral vector of BMP-7 also protected HPMCs from EMT. Furthermore, adenoviral BMP-7 transfection decreased peritoneal EMT and ameliorated peritoneal thickening in an animal model of peritoneal dialysis. In summary, high concentrations of glucose induce a reversible EMT of HPMCs, associated with decreased production of HGF and BMP-7. Treatment of HPMCs with HGF or BMP-7 blocks high glucose-induced EMT, and BMP-7 ameliorates peritoneal fibrosis in an animal model of peritoneal dialysis.

Animal Models in Peritoneal Dialysis: More Questions than Answers?

The development of an adequate animal model for peritoneal research remains an object of concern. In vivo peritoneal dialysis (PD) research is hampered by the large variety of available models that make interpretation of results and comparison of studies very difficult. Species and strain of experimental animals, method of peritoneal access, study duration, measures of solutetransport and ultrafiltration, and sampling for histology differ substantially among the various research groups. A collective effort to discuss the shortcomings and merits of the different experimental models may lead to a consensus on a standardized animal model of PD.

Animal Models in Peritoneal Dialysis Research: A Need for Consensus

The development of an adequate animal model for peritoneal research remains an object of concern. In vivo peritoneal dialysis (PD) research is hampered by the large variety of available models that make interpretation of results and comparison of studies very difficult. Species and strain of experimental animals, method of peritoneal access, study duration, measures of solute transport and ultrafiltration, and sampling for histology differ substantially among the various research groups. A collective effort to discuss the shortcomings and merits of the different experimental models may lead to a consensus on a standardized animal model of PD.

Effects of intraperitoneal heparin on peritoneal transport in a chronic animal model of peritoneal dialysis.

Heparin has anti-inflammatory effects and is often added to the peritoneal dialysis fluid to prevent fibrin formation. Conjugation of heparin to the surface of biomaterials has been shown to improve its biocompatibility. In this study, we describe for the first time an experimental chronic peritoneal dialysis model with repeated dwell studies in non-uraemic rats and evaluate the effect of addition of heparin to glucose-based peritoneal dialysis fluid on peritoneal fluid and solute transport. Wistar male rats, weighing 340+/-15 g, with implanted peritoneal catheters were infused during 1 month, twice per day with 20 ml of Dianeal 1.36%+antibiotics (AB; n = 10) or Dianeal 1.36%+antibiotics+heparin 2500 U/l (HAB; n = 9). After 10 (DS 1) and 30 days (DS 2), a dwell study was performed in rats with free access to drinking water, by infusing 30 ml of Dianeal 3.86%. Dialysate samples were obtained at 0, 2, 30, 60, 120 and 240 min. Blood samples were drawn before and at the end of the dwell. Radiolabelled serum albumin was used as macromolecular volume marker. Peritoneal volumes during DS 1 were significantly greater for the HAB group as compared with the AB group. No differences in ultrafiltration were found during DS 2 for HAB vs AB. However, peritoneal volumes were significantly higher for DS 2 compared with DS 1 in the AB group. The amount of glucose absorbed over time did not differ between the solutions, while fluid absorption tended to be lower in the HAB group. Heparin may improve peritoneal fluid transport possibly due to better healing and reduced peritoneal inflammation as shown in this novel animal model of chronic peritoneal dialysis with repeated dwell studies.

Exit-site infection induced by Staphylococcus aureus (SA) and its intervention in Animal Model of Peritoneal Dialysis(PD)

Exit-site infection induced by Staphylococcus aureus (SA) and its intervention in Animal Model of Peritoneal Dialysis(PD)

Amphotericin selectively increases peritoneal ultrafiltration.

Because amphotericin B is known to affect transport rates across biologic membranes, the effects of this agent on transport parameters in an animal model of peritoneal dialysis were investigated. When amphotericin B in doses ranging from 0.5 to 25 mg/kg was instilled intraperitoneally with commercial dialysis solution, diffusive clearances of phosphate and urea did not differ from control values measured in the same animals, and only a modest increase in potassium clearance was detected. Ultrafiltration due to the osmotic gradient induced by the dextrose content of the dialysis solution increased significantly to 0.31 mL/kg/min with amphotericin B, compared with control values of 0.18 mL/kg/min. The drug did not affect dextrose transport and the osmotic gradient did not differ in the two groups. Hence, the ultrafiltration coefficient was higher with amphotericin B (14 microL/kg/min/mosm), than during control dialyses (6 microL/kg/min/mosm). Increased water flux was detected at the lowest dose and there was no dose relationship over the range studied. Amphotericin B may be the type of agent that will be clinically useful in patients with reduced peritoneal ultrafiltration capacity, and safer analogues should be explored.