Peritoneal fibrosis and high transport are induced in mildly pre-injured peritoneum by 3,4-dideoxyglucosone-3-ene in mice.

Peritoneal dialysis (PD) solution contains high concentrations of glucose and glucose degradation products (GDPs). One of several GDPs--3,4-dideoxyglucosone-3-ene (3,4-DGE)--was recently identified as the most reactive and toxic GDP in PD fluids. In vitro, 3,4-DGE has been shown to induce mesothelial cell damage; however, its role in peritoneal fibrosis in vivo remains unclear. In the present study, we intraperitoneally administered chlorhexidine gluconate (CG) for mild peritoneal injury, and we then injected 3,4-DGE [38 µmol/L (low concentration) or 145 µmol/L (high concentration)] 5 times weekly for 4 weeks. Significant thickening of the parietal peritoneal membrane was observed only when treatment with low or high concentrations of 3,4-DGE occurred after CG administration, but not when either CG or 3,4-DGE alone was given. The combination of CG and 3,4-DGE also caused upregulation of messenger RNA expression of transforming growth factor ß1, connective tissue growth factor, fibronectin, collagen type 1 α1 chain, alpha smooth muscle actin (α-SMA), vascular endothelial growth factor 164, NADPH oxidase 1 and 4, p22phox, p47phox, and gp91phox in peritoneal tissue. Treatment with CG alone was sufficient to cause significant F4/80-positive macrophage infiltration, appearance of α-SMA-positive cells, and vessel formation in the submesothelial layer. Addition of 3,4-DGE markedly enhanced those changes and induced apoptosis, mainly in leukocytes. The concentration of 3,4-DGE in the abdominal cavity declined more rapidly in CG-treated mice than in PBS-treated mice. Peritoneal membrane permeability determined by peritoneal equilibration test showed high transport conditions in peritoneum treated with both CG and 3,4-DGE. These results indicate that, when mild peritoneal damage is already present, 3,4-DGE causes peritoneal thickening and fibrosis, resulting in deterioration of peritoneal membrane function.

Glutathione depletion as a mechanism of 3,4-dideoxyglucosone-3-ene-induced cytotoxicity in human peritoneal mesothelial cells: role in biocompatibility of peritoneal dialysis fluids.

BACKGROUND: The potential detrimental effects of glucose degradation products (GDPs) contained in peritoneal dialysis fluids (PDFs) on peritoneal mesothelial cells (PMCs) may impair intraperitoneal homeostasis in patients undergoing continuous ambulatory peritoneal dialysis (CAPD). A recent study showed that 3,4-dideoxyglucosone-3-ene (3,4-DGE) was the most strongly cytotoxic among all identified GDPs in PDFs. The present study examined the effects of clinically relevant concentrations of 3,4-DGE on the proliferative capacity of PMCs and oxidative injury to them. METHOD: The concentrations of eight GDPs in commercially available PDFs were determined by HPLC. The effect of cell growth media spiked with GDPs on the proliferation capacity of PMCs was evaluated. As a marker of the cellular redox status, total cellular glutathione (tGSH) was determined in PMCs incubated with GDPs. The reaction of 3,4-DGE with GSH under nonenzymatic conditions was analysed by liquid chromatography-electrospray ionization-mass spectrometry (LC-ESI-MS). RESULT: The concentrations of 3,4-DGE in a heat-sterilized single-compartment standard-type PDF (S-PDF) and in a heat-sterilized dual-chamber-type PDF (N-PDF) were 16 microM and 1.7 microM, respectively. The most cytotoxic GDP was 3,4-DGE, and the concentration at which it causes 50% inhibition of cell growth was 35 microM. A significant decrease in the cellular tGSH levels was observed in the cells treated with 10 microM 3,4-DGE. 3,4-DGE disappeared on incubation with GSH under nonenzymatic conditions for 1 h, and the 3,4-DGE-GSH conjugate was confirmed by accurate mass measurement using LC-ESI-MS. These data demonstrated that the change in the cellular redox status by GSH depletion might be a contributory factor in 3,4-DGE-induced cytotoxicity. CONCLUSION: 3,4-DGE is a highly reactive GDP and is responsible for the depletion of the total intracellular glutathione. 3,4-DGE has an intense impact on PMC growth at concentrations found in standard PDFs. It is desired that the amount of 3,4-DGE in PDFs should be minimized.

Clinical application of computer-aided diagnostic system for harmonious introduction of complementary dialysis therapy.

In chronic peritoneal dialysis (PD) therapy, peritoneal permeability is gradually enhanced over the duration of the therapeutic course, leading to a grave decline in the therapeutic efficiency. In recent years, a novel therapy (CD therapy), which integrates PD therapy with hemodialysis therapy, is being applied to end-stage PD patients to complement the decline of therapeutic efficiency caused by the grave degeneration of the peritoneal tissue. To realize a harmonious introduction of the CD therapy, this study developed a useful index (KAu/c), which evaluates both therapeutic efficiency and degeneration of peritoneal tissue. Using a mathematical model and KAu/c, we were able to validate the therapeutic efficiency in the PD patients, and, in one case, propose a better prescription for the patient by employing the CD therapy. The clinical implementation of this methodology is indispensable with regard to expanding the therapeutic monitoring system for renal replacement therapy.

Development of a computer-aided diagnosis system for continuous peritoneal dialysis: an availability of the simultaneous numerical optimization technique for kinetic parameters in the peritoneal dialysis model.

We developed a novel diagnostic system for continuous peritoneal dialysis, which evaluates the peritoneal permeability and hydraulic conductance (peritoneal function) by applying the kinetic model and a clinical test with minimum nursing time. Kinetic parameters for the peritoneal function were determined by the simultaneous numerical optimization techniques (SNOT). Furthermore dialysis outcome and ultrafiltration volume were estimated and predicted by using the kinetic model with a set of optimal kinetic parameters, which were in agreement with measured data (r(2)>0.82). The clinical implementation of the SNOT is very useful to explore the better prescriptions for each patient's clinical condition.

Impact of 3,4-dideoxyglucosone-3-ene (3,4-DGE) on cytotoxicity of acidic heat-sterilized peritoneal dialysis fluid.

Of the glucose degradation products (GDPs) in glucose-rich peritoneal dialysate, we investigated the influence of 3,4-dideoxyglucosone-3-ene (3,4-DGE) on the cytotoxicity of acidic heat-sterilized peritoneal dialysis fluid (L-H PDF) using human peritoneal mesothelial cells (HPMC). We prepared acidified filtration-sterilized PDF (glucose concentration 3.86%) containing eight types of added GDP [3,4-DGE, glyoxal (GO), methylglyoxal (MGO), 3-deoxyglucosone (3-DG), formaldehyde (FA), acetaldehyde (AA), 5-hydroxymethyl-2-furaldehyde (5-HMF), and furfural (FF)] or seven types of GDP (GO, MGO, 3-DG, FA, AA, 5-HMF, and FF). HPMC were exposed to these two types of solution and acidic heat-sterilized PDF (glucose concentration 3.86%, L-H 3.86) for 4 h. Cell viability was determined by 3,(4,5-dimethythiazol-2-yl)2,5-diphenyl-terazolium bromide (MTT) assay. MTT viability was decreased significantly compared with the control when treated with L-H 3.86 or acidified neutral filtration-sterilized PDF (glucose concentration 3.86%) containing eight GDPs. However, no significant decrease in MTT viability was observed when HPMC were treated with acidified neutral filtration-sterilized PDF (glucose concentration 3.86%) containing seven GDPs. Thus, 3,4-DGE strongly affects the cytotoxicity of L-H PDF. It is suggested that the cytotoxicity of L-H PDF is based on the presence of 3,4-DGE.

Development of a computer-aided diagnosis system for a new modality of renal replacement therapy: an integrated approach combining both peritoneal dialysis and hemodialysis.

The authors developed a computer-aided diagnosis system that includes a simple clinical test for the chronic renal disease patient who needs an integrated approach that combines both peritoneal dialysis and hemodialysis (PD-HD therapy). In this case study, the system simulated and estimated the dialysis outcome, the ultrafiltration volume and nutritional analysis by employing a pharmacokinetic model, and assessed the peritoneal permeable enhancement that can be a grave complication with peritoneal dialysis. This system requires only a minimum amount of nursing time and may be able to predict the optimal treatment schedule for PD-HD therapy and provide therapeutic monitoring in long-term peritoneal dialysis.

Synergistic cytotoxicity of acidity and 3,4-Dideoxyglucosone-3-ene under the existence of lactate in peritoneal dialysis fluid.

Of the non-physiological compounds in glucose-rich peritoneal dialysis fluid, we investigated the synergistic cytotoxicity of acidity and 3,4-Dideoxyglucosone-3-ene(3,4-DGE) under the existence of lactate using human peritoneal mesothelial cells (HPMC). The effect of pH on cell viability at various levels of pH (5.5, 6.7, 7.15), with or without lactate was examined by adding 1N-HCl to phosphate buffer solution. We also examined the cytotoxic effects of 3,4-DGE and pH (5.5, 6.7 or 7.15). Additionally, we compared the cytotoxic effects of 3,4-DGE and pH (5.5, 6.7 or 7.15) under existence of lactate (40 meq/L) or absence of lactate. The cells were exposed to these solutions for 2 or 4 h. Cell viability was determined by MTT (3-[4, 5-dimethylthiazol-2-yl]-2, 5-diphenylterazolium bromide) assay. 3,4-DGE or acidic solution alone had no significant effects on MTT viability under the absence of lactate. However, acidic solutions containing 3,4-DGE significantly decreased MTT viability under the existence of lactate. The MTT viability of HPMC was not decreased by 3,4-DGE or acidity alone under the absence of lactate. However, the combination of acidity and 3,4-DGE markedly decreased MTT viability under the existence of lactate, strongly suggesting the synergistic cytotoxicity of 3,4-DGE and acidity under the existence of lactate.