Serum levels of nitric oxide and endothelin-1 in patients treated with continuous ambulatory peritoneal dialysis

The Behavior of the Type of Peritoneal Transport in the Inflammatory and Oxidative Status in Adults Under Peritoneal Dialysis

Peritoneal dialysis (PD) is an alternative for managing the end-stage renal disease (ESRD). The peritoneal membrane (PM) is not just a membrane that passively responds to diffusion and convection. The characteristics of PM result in the peritoneal equilibrium test (PET) and with this test is possible to obtain the type of peritoneal transport (PT). The patient on PD can be classified in different types of PT as; Low, Low Average, High Average, and High. The aim of the study was to compare the inflammatory cytokines, oxidants, antioxidants, and oxidative DNA damage markers in the different types of PT. A cross-sectional analytical study of 77 adult PD patients was performed. Levels of lipoperoxides (LPO) were higher in all types of PT vs. healthy volunteer controls (HC) (p < 0.0001). Nitric oxide (NO) levels were found significantly down-regulated in all types of PT (p < 0.0001). The activity of the superoxide dismutase enzyme (SOD) was found to be significantly increased in all types of PT vs. the HC (p < 0.0001). The levels of the DNA repair enzyme were found to be decreased in all types of PT. The levels of the pro-inflammatory cytokines TNF-α, IL-6, the marker of oxidative DNA damage, 8-IP and the total antioxidant capacity (TAC) were all significantly decreased, contrary to the levels in HC, possibly by the clearance in the dialysis fluid in all types of PT or due to down-regulation of their expression. In conclusion, we found significant changes in markers of inflammation, oxidative stress, and oxidative damage to DNA in all types of PT; Low, low average, high average, and high PT in the values of D/P creatinine at 4 h compared to HC.

The relationship between brain-derived neurotrophic factor levels, oxidative and nitrosative stress and depressive symptoms: a study on peritoneal dialysis

BACKGROUND

Depression is one of the most commonly encountered psychiatric problems in peritoneal dialysis (PD) patients. Our aim was to investigate the associations between oxidative and nitrosative stress (O&NS) and brain-derived neurotrophic factor (BDNF) in PD patients with elevated depressive symptoms (EDS).

METHODS

Eighty-three patients with PD and 84 healthy controls were enrolled in this study. In PD patients, two subgroups were formed: 28 with and 55 without EDS. EDS were defined as a Beck Depression Inventory (BDI) score ≥17 in patients. Serum malondialdehyde (MDA) erythrocyte, glutathione (GSH) levels measured spectrophotometrically. Serum superoxide dismutase (SOD) activity, nitric oxide (NO) and BDNF levels were determined by ELISA.

RESULTS

While MDA and NO levels were higher, levels of SOD, GSH and BDNF were lower in PD patients compared to controls (p < 0.001). The patients with EDS had higher levels of MDA and lower levels of BDNF as compared to those without EDS (p < 0.005). In linear regression analysis, the BDNF levels were dependently associated with SOD levels in PD patients (B: 0.274, p: 0.043). In addition, while a negative correlation existed between BDI scores with BDNF levels (r = -0.312, p = 0.004), a positive correlation was present between BDI scores and MDA levels (r = 0.320, p = 0.005) in PD patients.

CONCLUSION

Our results suggest the presence of high O&NS and low antioxidant capacity accompanied with decreased levels of BDNF in PD patients, especially those with EDS were deeper. These may represent the risk factors for cellular injury and might reveal part of the mechanism causing the depressive state in PD patients.