Heat sterilization of peritoneal dialysis solutions influences ingestive behavior in non-uremic rats

Systemic and local impact of glucose and glucose degradation products in peritoneal dialysis solution

The main osmotic agent used in the peritoneal dialysis (PD) solution is glucose because of its great osmotic power, simple metabolism, and safety. Once into the systemic circulation, however, glucose can be a cause for metabolic complications including hyperglycemia, obesity, and dyslipidemia. The glucose absorbed from peritoneal cavity leads to insulin resistance and hyperglycemia, which is associated with oxidative stress. Long-term exposure of peritoneal membrane to glucose in PD solution also has local effects such as functional and structural changes leading to peritoneal membrane failure. Moreover, the intraperitoneal glucose absorption induces conditions similar to postprandial hyperglycemia, which is a proven independent risk factor of coronary artery disease in patients with type 2 diabetes. Though speculative, glucose toxicity might explain a higher mortality of PD patients after the first few years compared with those on hemodialysis. Glucose degradation products (GDPs) induce apoptosis of peritoneal mesothelial cells (PMCs), renal tubular epithelial cells, and endothelial cells, and facilitating epithelial mesenchymal transition of PMCs. GDPs provide a stronger reactivity than glucose in the formation of advanced glycation end-products, a known cause for microvascular complications and arteriosclerosis. Unfortunately, clinical studies using a low-GDP PD solution have provided mixed results on the residual renal function, peritonitis, peritoneal membrane function, and mortality; consistent outcome data are not readily available at present.

Comparison of warm and cold contrast media for hysterosalpingography: a prospective, randomized study

OBJECTIVE

To compare the use of warm medium and cold medium for alleviating pain and side effects during hysterosalpingography (HSG).

DESIGN

Prospective randomized study.

SETTING

University hospital.

PATIENT(S)

Two hundred infertile women who needed HSG were recruited from January 2010 to June 2011. The exclusion criteria were acute low reproductive duct infection, known hypersensitivity to iodine, genital bleeding, or malignancy.

INTERVENTION(S)

Subjects were randomized to undergo HSG using a medium prewarmed to 37°C or a medium at room temperature.

MAIN OUTCOME MEASURE(S)

Incidence of vasovagal episodes and visual analog scale (VAS) pain scores during HSG.

RESULT(S)

Patients' VAS pain scores during HSG were significantly lower in the warm media group initially but showed no statistical difference at 30 minutes after injection. Medium temperature showed a linear association with VAS score. The total number of vasovagal episodes was higher in the cold medium group.

CONCLUSION(S)

Warm contrast medium alleviates the pain associated with HSG and decreases the incidence of vasovagal episodes during HSG.

CLINICAL TRIALS REGISTRATION NUMBER

NCT01339338.

Bicarbonate-Based Peritoneal Dialysis Solution has Less Effect on Ingestive Behavior than Lactate-Based Peritoneal Dialysis Solution

Objective

The anorexia seen in peritoneal dialysis (PD) patients may be due partially to factors of dialysis solutions, such as pH and buffering agent. We tested the effects of different PD solutions in an experimental rat model for appetite.

Design

The intraoral intake of a sucrose solution from an implanted intraoral cannula in freely moving male Wistar rats was used to evaluate appetite at 30 minutes and 120 minutes after intraperitoneal (IP) infusion of bicarbonate (25 mmol/L)/lactate (15 mmol/L)-based PD solution (P) and conventional lactate (40 mmol/L)-based PD solution (D) with different concentrations of glucose. We also tested different buffer solutions containing lactate and bicarbonate with different pH but with no glucose.

Results

The IP infusion as such and the 30 mL volume did not inhibit appetite; however, appetite was significantly less inhibited by P than by D in the 1.36%, 2.27%, and 3.86% solutions ( p < 0.05). Furthermore, intraoral intake was significantly higher in rats receiving IP solution with bicarbonate buffer (pH 7.4) than with lactate buffer ( p < 0.05), whereas there was no significant difference in intraoral intake for lactate with pH 5.5, pH 6.6, or pH 7.4.

Conclusions

The bicarbonate/lactate solution inhibited appetite less than the lactate solution; this was due partially to the use of bicarbonate. The results show possible benefit on appetite of reducing the lactate concentration in PD solutions.

Impact of dialysis duration and glucose absorption on nutritional indices in stable continuous ambulatory peritoneal dialysis patients

OBJECTIVE

The presence of comorbidity is a risk factor for both poor nutrition and poor outcome in continuous ambulatory peritoneal dialysis (CAPD) patients. In CAPD specifically, peritoneal glucose load is associated with a possible suppression of appetite, contributing to protein malnutrition. This study sought to explore the factors associated with malnutrition indices in stable peritoneal dialysis patients without significant comorbidity, and to assess the impact of peritoneal glucose absorption on nutrition parameters.

DESIGN

This was a cross-sectional observational study.

SETTING

This study took place in the peritoneal dialysis department of a university hospital, and involved outpatients.

PATIENTS

There were 23 stable, comorbidity-free CAPD patients (9 women), aged 54 +/- 12 years, with a CAPD duration of 28 +/- 25 months (values are mean +/- SD unless otherwise noted).

METHODS

Nutritional status was evaluated by means of anthropometric and serum measurements. A peritoneal equilibration test was performed, and daily glucose absorption was measured. Lean body mass (LBM) was assessed through creatinine kinetics.

RESULTS

A significant impact of CAPD duration was found. Patients in the upper quartile of CAPD duration had worse nutritional parameters compared with the rest of the group: their mid-upper-arm surface area and fat surface area were lower (65 +/- 9 cm(2) vs. 78 +/- 6.2 cm(2) and 16 +/- 5.3 cm(2) vs. 26 +/- 9.5 cm(2), respectively, P < .05), their albumin concentration was lower (36 +/- 0.5 g/L vs. 42 +/- 4 g/L, P < .05), and their cholesterol and triglycerides were lower (3.5 +/- 0.5 vs. 5.2 +/- 1 mmol/L and 1.3 +/- 0.6 vs. 2.3 +/- 1.1 mmol/L, respectively, P < .05). No significant correlations between peritoneal glucose absorption and these indices were found.

CONCLUSION

The duration of dialysis treatment, but not peritoneal glucose absorption, is a predictor of malnutrition in stable, comorbidity-free CAPD patients.

3,4-Dideoxyglucosone-3-ene induces apoptosis in renal tubular epithelial cells

Diabetes complications are caused by hyperglycemia. Hyperglycemia results in increased concentrations of glucose degradation products. The study of peritoneal dialysis solution biocompatibility has highlighted the adverse effects of glucose degradation products. Recently, 3,4-dideoxyglucosone-3-ene (3,4-DGE) has been identified as the most toxic glucose degradation product in peritoneal dialysis fluids. Its role in renal pathophysiology has not been addressed. 3,4-DGE induces apoptosis in murine renal tubular epithelial cells in a dose- and time-dependent manner. Peak apoptosis is observed after 72 h of culture. The lethal concentration range is 25-50 micromol/l. 3,4-DGE results in Bax oligomerization, release of cytochrome c from mitochondria, activation of caspases-9 and -3, and Bid proteolysis. Apoptosis induced by 3,4-DGE is caspase dependent and could be prevented by the broad-spectrum caspase inhibitor zVAD-fmk (Z-Val-Ala-DL-Asp-fluoromethylketone) and by specific inhibitors of caspases-2, -8, and -9. However, caspase inhibition did not prevent eventual cell death. In contrast, antagonism of Bax by a Ku-70-derived peptide or antisense oligonucleotides prevented both apoptosis and cell death. In conclusion, 3,4-DGE promotes apoptosis of cultured renal parenchymal cells by a Bax- and caspase-dependent mechanism. A role for 3,4-DGE in diabetes complications in the kidney and in the modulation of residual renal function in peritoneal dialysis should be further explored.