Hemodialysis induces p66(shc) gene expression in nondiabetic humans: correlations with oxidative stress and systemic inflammation

PTX3 in serum induces renal mesangial cell proliferation but has no effect on apoptosis

The present study aimed to investigate the effect of pentraxin 3 (PTX3) on the regulation of proliferation and apoptosis in human glomerular mesangial cells (HMCs). Small interfering (si)RNA was designed and synthesized to inhibit the expression of endogenous PTX3, and the effects on the proliferation and apoptosis of HMCs were detected by flow cytometry and an MTT assay. Western blot analysis was used to detect the activation of mitogen-activated protein kinase (MAPK) proteins in HMCs with PTX3 knockdown. Three siRNAs targeting PTX3 were individually transfected into HMCs for 48 h, and reverse-transcription quantitative PCR demonstrated that the relative mRNA expression of PTX3 was significantly decreased in all groups by up to 79.62% of that in the control group (P<0.05). Following transfection with PTX3-siRNA, the viability of an HMC line was significantly decreased in comparison with that of a control group transfected with scrambled siRNA. However, PTX3-siRNA did not significantly effect early and late apoptotic cell populations in HMCs compared with those in the control. Endogenous PTX3 interference was found to significantly decrease p38 MAPK, extracellular signal-regulated kinase 1/2 and c-Jun N-terminal kinase phosphorylation. In conclusion, silencing of PTX3, inhibited the proliferation of HMCs via MAPK pathways, but exerted no effect on the apoptosis of HMCs.

Contribution of monoamine oxidases to vascular oxidative stress in patients with end-stage renal disease requiring hemodialysis

Arteriovenous fistula (AVF) is the "lifeline" for patients with end-stage renal disease (ESRD) undergoing hemodialysis. AVF maturation failure is a poorly understood process, one of the contributors being endothelial dysfunction due to oxidative stress. Monoamine oxidases (MAOs) A and B were recently identified as novel sources of vascular oxidative stress. The aim of the present study was to assess the contribution of MAOs to the endothelial dysfunction in patients with ESDR with indication of hemodialysis. Fragments of brachial artery collaterals were harvested from ESRD patients during the surgical procedure aimed at creating the vascular access in the cubital fossa. The effect of increasing concentrations (10, 30, 100 μmol/L) of the irreversible MAO-A inhibitor, clorgyline, and MAO-B inhibitor, selegiline, on endothelial-dependent relaxation (EDR) in response to cumulative doses of acetylcholine was studied in isolated phenylephrine-preconstricted vascular rings. Hydrogen peroxide (H₂O₂) production was assessed using ferrous oxidation xylenol orange assay. We showed that incubation of brachial rings with MAO inhibitors significantly improved EDR and attenuated H₂O₂ generation in patients with ESRD. MAO-related oxidative stress might contribute to the primary dysfunction/non-maturation of the AVF and MAO inhibitors could improve maturation and long-term patency of the vascular access in dialysis patients.

Hemodialysis decreases serum brain-derived neurotrophic factor concentration in humans

In the present study we have evaluated the effect of a single hemodialysis session on the brain-derived neurotrophic factor levels in plasma [BDNF](pl) and in serum [BDNF](s) as well as on the plasma isoprostanes concentration [F(2) isoprostanes](pl), plasma total antioxidant capacity (TAC) and plasma cortisol levels in chronic kidney disease patients. Twenty male patients (age 69.8 ± 2.9 years (mean ± SE)) with end-stage renal disease undergoing maintenance hemodialysis on regular dialysis treatment for 15-71 months participated in this study. A single hemodialysis session, lasting 4.2 ± 0.1 h, resulted in a decrease (P = 0.014) in [BDNF](s) by ~42 % (2,574 ± 322 vs. 1,492 ± 327 pg ml(-1)). This was accompanied by an increase (P < 10(-4)) of [F(2)-Isoprostanes](pl) (38 ± 3 vs. 116 ± 16 pg ml(-1)), decrease (P < 10(-4)) in TAC (1,483 ± 41 vs. 983 ± 35 trolox equivalents, μmol l(-1)) and a decrease (P = 0.004) in plasma cortisol level (449.5 ± 101.2 vs. 315.3 ± 196.3 nmol l(-1)). No changes (P > 0.05) in [BDNF](pl) and the platelets count were observed after a single dialysis session. Furthermore, basal [BDNF](s) in the chronic kidney disease patients was significantly lower (P = 0.03) when compared to the age-matched control group (n = 23). We have concluded that the observed decrease in serum BDNF level after hemodialysis accompanied by elevated [F(2)-Isoprostanes](pl) and decreased plasma TAC might be caused by enhanced oxidative stress induced by hemodialysis.

Evidence for augmented oxidative stress in the subjects with type 1 diabetes and their siblings: a possible preventive role for antioxidants

BACKGROUND/OBJECTIVES

Oxidative stress (OS) is thought to be involved in both development of type 1 diabetes (T1D) and its further complications. In this study, certain biomarkers of OS were compared among the subjects with T1D, their non-diabetic siblings and unrelated healthy controls.

SUBJECTS/METHODS

Known cases of T1D from both sexes aged 5-25 years were enrolled in a case-control study (n(1)=60). There were two control groups; non-diabetic siblings (n(2)=60) and unrelated apparently healthy subjects (n(3)=60). Anthropometric, dietary and laboratory assessments were done.

RESULTS

There was no significant difference in dietary data among the groups. Total antioxidant capacity was significantly lower in T1D than both related and unrelated controls (1.6 ± 0.05, 1.7 ± 0.05 and 1.8 ± 0.06 mmol BSA equivalent/l, respectively, P=0.044). Both T1D subjects and their siblings showed lower glutathione peroxidase (GSH-px) levels (median (interquartile range): 22.2 (28.6), 29.9 (23) and 41.8 (73.6) U/ml, respectively, P=0.006). On the contrary, superoxide dismutase concentrations were significantly higher in T1D group and the siblings than unrelated healthy controls (243 (45.3), 157.8 (176.9) and 27.9 (8.7) U/l, respectively, P<0.001). Serum concentrations of GSH correlated with energy intake in the siblings (r=0.521, P<0.001) and unrelated controls (r=0.268, P=0.042) but not in T1D group. The associations remained significant after controlling for blood glucose (r=0.437, P=0.001 and r=0.420, P=0.011, respectively) in both the groups.

CONCLUSION

Augmented OS in the siblings may indicate an increased requirement for antioxidants in genetically diabetes-prone subjects.

Activation of AQP4, p66Shc and endoplasmic reticulum stress is involved in inflammation by carrageenan and is suppressed by argirein, a derivative of rhein

Objectives

We investigated the effect of argirein on acute inflammation edema and examined that aquaporin 4 (AQP4), p66Shc and activating transcription factor (ATF-6) might be involved in carrageenan-induced rat paw inflammation and be reversed by argirein, rhein and indometacin, but not l-arginine.

Methods

Inflammation was produced by carrageenan injected into rat paw and treated orally with argirein (100 mg/kg), rhein (100 mg/kg), l-arginine (100 mg/kg) or indometacin (5 mg/kg). Inflammatory oedema and biomarkers were examined.

Key findings

Swelling was reduced by argirein, rhein and indometacin; argirein was more effective than rhein at 1 h following medication. Activation of AQP4, p66Shc, ATF-6, NADPH oxidase subunits p22phox, gp91phox and matrix metalloproteinase 2 (P &lt; 0.01) was significant and was suppressed by arginine, rhein and indometacin but not by l-arginine.

Conclusions

Activated AQP4, endoplasmic reticulum stress and p66Shc were actively implicated in the inflammation and these were suppressed by argirein, and its activity is favorable due to synergism in combination with l-arginine.