Changying Xing

Effects of coupled plasma filtration adsorption on immune function of patients with multiple organ dysfunction syndrome.

Objective To investigate the effects of coupled plasma filtration adsorption (CPFA) on the immune function of patients with multiple organ dysfunction syndrome (MODS). Methods This study was a prospective, pilot, before-and-after self-crossover, clinical trial. Seven patients diagnosed with MODS and severe infection were randomly allocated to both 10 hours of CPFA and 10 hours of high-volume hemofiltration (HVHF) with a 12-hour interval and in random order. Serum concentrations of 7 cytokines including tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), interleukin-1β (IL-1β), interleukin-10 (IL-10), interleukin-1 receptor antagonist (IL-1Ra), and soluble tumor necrosis factor receptors 1 and 2 (sTNFR1 and sTNFR2) were measured during each treatment. The HLA-DR expression by the blood monocytes and the TNF-α production by the patients’ blood (both spontaneous and lipopolysaccharide stimulated) were tested before and after the treatment. TNF-α production of normal human monocytes (THP-1 cells) incubated in vitro with the patient plasma was also measured. Results During CPFA, the fall in serum TNF-α and rise in serum IL-1Ra coincided with the rise in ratios of sTNFR2/TNF-α and IL-1Ra/IL-1β (p<0.05), which were different from those seen within HVHF (p<0.05). HLA-DR expression increased after CPFA (84.32% ± 4.63% vs. 73.65% ± 11.52%, p=0.037), but there was no change after HVHF (p>0.05). Spontaneous and lipopolysaccharide-induced TNF-α production increased over time with CPFA (p=0.038, p=0.034, respectively), but did not change with HVHF (p>0.05). Patient plasma suppressed the production of TNF-α by cultured normal monocytes. This effect decreased over time with CPFA (p=0.041), but there was no effect with HVHF (p>0.05). Conclusions CPFA was superior to HVHF in increasing the ratios of antiinflammatory to proinflammatory mediators, improving antigen presentation ability, and restoring leukocyte responsiveness. These findings suggest a potential role for CPFA in the treatment of MODS.

The roles of oxidative stress, endoplasmic reticulum stress, and autophagy in aldosterone/mineralocorticoid receptor-induced podocyte injury.

Podocytes play an important role in the pathogenesis and progression of glomerulosclerosis. Recent studies indicate that aldosterone/mineralocorticoid receptor (MR) is a major contributor of chronic kidney disease (CKD) progression. Aldosterone/MR induces glomerular podocyte injury, causing the disruption of the glomerular filtration barrier and proteinuria. The present study investigated the mechanisms by which aldosterone/MR mediated podocyte injury, focusing on the involvement of oxidative stress, endoplasmic reticulum (ER) stress, and autophagy. We observed that aldosterone/MR induced ER stress and podocyte injury both in vivo and in vitro. Blockade of ER stress significantly reduced aldosterone/MR-induced podocyte injury. In addition, we found that ER stress-induced podocyte injury was mediated by CCAAT/enhancer-binding protein (C/EBP) homologous protein (Chop). Interestingly, autophagy was also enhanced by aldosterone/MR. Pharmacological inhibition of autophagy resulted in increased apoptosis. Inhibition of ER stress significantly reduced aldosterone/MR-induced autophagy. In addition, the activation of ER stress increased the formation of autophagy, which protected podocytes from apoptosis. Moreover, we observed that the addition of ROS scavenger, N-acetyl cystein (NAC), blocked both ER stress and autophagy by aldosterone/MR. Collectively, these results suggest that oxidant stress-mediated aldosterone/MR-induced podocyte injury via activating ER stress, which then triggers both Chop-dependent apoptosis and autophagy to cope with the injury. These findings may guide us to therapeutic strategies for glomerular diseases.

P53 Contributes to Cisplatin Induced Renal Oxidative Damage via Regulating P66shc and MnSOD.

Background/Aims: Cisplatin is widely used to treat malignancies. However, its major limitation is the development of dose-dependent nephrotoxicity. The precise mechanisms of cisplatin-induced kidney damage remain unclear. Previous study demonstrated the central role of mitochondrial ROS (mtROS) in the pathogenesis of cisplatin nephrotoxicity. The purpose of this study was to explore the mechanism of mtROS regulation in cisplatin nephrotoxicity. Methods: p53, MnSOD and p66shc were detected at mRNA and protein levels by qPCR and western blot in HK2 cells. mtROS levels were determined by DCFDA and MitoSOX staining. Cell viability and cell apoptosis were accessed by CCK-8 assay, TUNEL assay and flow cytometry, respectivesly. siRNAs were used to knock down p53 and p66shc expression and subsequent changes were observed. In vivo assays using a mouse model of cisplatin-induced acute kidney injury were used to validate the in vitro results. Results: In HK2 cells, cisplatin exposure decreased the MnSOD and increased the expression of p53 and p66shc. MnTBAP, a MnSOD mimic, blocked cisplatin-induced the generation of mtROS and cell injury. P66shc and p53 siRNAs rendered renal cells resistant to cisplatin-induced mtROS production and cell death. Furthermore, knockdown of p53 restored MnSOD and inhibiting p66shc. Consistent with these results, we revealed that p53 inhibitor reduced cisplatin-induced oxidative stress and apoptosis by regulating MnSOD and p66shc in the kidney of cisplatin-treated mice. Conclusion: Our study identifies activation of p53 signalling as a potential strategy for reducing the nephrotoxicity associated with cisplatin treatments and, as a result, broadens the therapeutic window of this chemotherapeutic agent.

Plasma FGF23 levels and heart rate variability in patients with stage 5 CKD

SummaryFibroblast growth factor 23(FGF23) is a bone-derived hormone which regulates mineral homeostasis but may also have a role in cardiovascular disease. Here, we found that higher plasma FGF23 was independently associated with decreased heart rate variability in stage 5 CKD patients and parathyroidectomy may reverse these abnormal indicators.IntroductionLower heart rate variability (HRV) in patients with chronic kidney disease (CKD) compared with healthy controls is associated with increased risk of cardiovascular disease (CVD). Higher levels of plasma FGF23 also predict higher risk of CVD. Here, we aimed to evaluate the relationship between plasma FGF23 levels and HRV in patients with stage 5 CKD and to investigate longitudinal changes of them together with the correlation between their changes in two severe secondary hyperparathyroidism (SHPT) subgroups with successful parathyroidectomy (PTX) and persistent SHPT.MethodsThis cross-sectional study included 100 stage 5 CKD patients, 78 controls, and a prospective study in two PTX subgroups classified as successful PTX (n = 24) and persistent SHPT (n = 4) follow-up. Blood examination and 24-h Holter monitoring for HRV were measured.ResultsMost HRV indices were lower in stage 5 CKD patients than in healthy controls, and plasma FGF23 levels were higher. In multivariate stepwise regression models, levels of plasma FGF23 and serum parathyroid hormone (PTH) were correlated with HRV. The successful PTX subgroup had significant improvements over baseline in HRV indices. Persistent SHPT subgroup had numerically similar changes in HRV indices. However, plasma FGF23 levels decreased in both subgroups.ConclusionsPlasma FGF23 levels were higher in CKD patients than in controls, much higher in patients with severe SHPT. FGF23 was independently associated with decreased HRV in stage 5 CKD. Successful PTX may reverse these abnormal indicators and contribute to decreases in the risk of cardiovascular disease.

High-glucose-based peritoneal dialysis solution induces the upregulation of VEGF expression in human peritoneal mesothelial cells: The role of pleiotrophin.

The aim of the present study was to investigate the effect of a high-glucose-based peritoneal dialysis solution (HGPDS) on the expression of pleiotrophin (PTN) and vascular endothelial growth factor (VEGF) in human peritoneal mesothelial cells (HPMCs) and the mechanisms through which fluvastatin (Flu) protects the peritoneal membrane in continuous ambulatory peritoneal dialysis (CAPD). HPMCs were cultured with HGPDS, Flu (10-8‑10-6 mol/l) and PTN (10‑30 nmol/l). The expression of PTN and VEGF was examined at the mRNA and protein level. To define the role of PTN in the regulation of VEGF expression, HPMCs were cultured with HGPDS in the presence or absence of the blocking peptide of PTN. The signaling pathways involved in PTN synthesis induced by HGPDS were also characterized. The phenotypic characteristics of HPMCs were observed under a light microscope. Cell viability was measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) colorimetry and the mRNA and protein expression of PTN, VEGF and ERK1/2 was assessed by RT‑PCR and the western blot analysis, respectively. Following incubation with HGPDS for 48 h, the morphology of the HPMCs changed from a typical cobblestone‑like appearance to a fibroblast‑like phenotype. The same alteration in the morphology of the HPMCs also occurred following incubation with 20 nmol/l PTN. Flu (10-6 mol/l), GSK650394 [a competitive inhibitor of serum/glucocorticoid-regulated kinase 1 (SGK1), 10-5 mol/l] and PD98059 (a competitive inhibitor of ERK1/2, 10-5 mol/l) improved the negative changes in cell morphology induced by HGPDS. The results of MTT assay revealed that the reduction in HPMC viability occurred in the groups treated with HGPDS and this reduction was partially restored by Flu, GSK650394 and PD98059. A significant improvement in cell viability, which had been decreased by HGPDS, was observed following treatment with Flu (10-6 mol/l), PD98059 (10-5 mol/l) or GSK650394 (10-5 mol/l) (P<0.05). Compared with the control, the mRNA and protein expression of PTN and VEGF significantly increased in the HPMCs treated with HGPDS (P<0.05). GSK650394 and PD98059 significantly decreased the high mRNA and protein expression levels of PTN and VEGF induced by HGPDS (P<0.05) and Flu had the same inhibitory effect as GSK650394 and PD98059 in a dose‑dependent manner (P<0.05). The mRNA and protein expression of VEGF increased following the incubation of HPMCs with 20 nmol/l PTN. By contrast, the mRNA and protein expression levels of VEGF in the HPMCs decreased in the presence of the blocking peptide of PTN. The results from the present study indicated that HGPDS increased the expression of PTN and VEGF in the HPMCs, and this increase was attenuated by Flu, GSK650394 and PD98059. The protein expression of phosphorylated ERK1/2 (p-ERK1/2) was decreased by GSK650394 in the HPMCs treated with HGPDS. Taken together, the protective effects of Flu in HPMCs may be partially achieved through the SGK1‑ERK1/2 signaling pathway.

Pink1/Parkin-mediated mitophagy play a protective role in cisplatin induced renal tubular epithelial cells injury

ABSTRACT Cisplatin often causes acute kidney injury (AKI) in the treatment of a wide variety of malignancies. Mitochondrial dysfunction is one of the main reasons for cisplatin nephrotoxicity. Previous study showed that Pink1 and Parkin play central roles in regulating the mitophagy, which is a key protective mechanism by specifically eliminating dysfunctional or damaged mitochondria. However, the mechanisms that modulate mitophagy in cisplatin induced nephrotoxicity remain to be elucidated. The purpose of this study was to investigate the effects of Pink1/Parkin pathway in mitophagy, mitochondrial dysfunction and renal proximal tubular cells injury during cisplatin treatment. In cultured human renal proximal tubular cells, we found that knockdown of Pink1/Parkin induced the aggravation of mitochondrial function, leading to the increase of cell injury through inhibition of mitophagy. Additionally, the overexpression of Pink1/Parkin protected against cisplatin‐induced mitochondrial dysfunction and cell injury by promoting mitophagy. Our results provide clear evidence that Pink1/Parkin‐dependent mitophagy has identified potential targets for the treatment of cisplatin‐induced AKI.

Different effect of cyclosporine and tacrolimus on renal expression of P-glycoprotein in human kidney transplantation.

OBJECTIVE To investigate the differential effects of cyclosporine (CsA) and tacrolimus (TAC) on renal expression of P-glycoprotein (P-gp) in a cohort of kidney transplant recipients. METHODS We enrolled 78 cadaveric kidney transplant recipients recurring basal immunosuppressive protocol with prednisone + mycophenolate mofetil + calcineurin inhibitor (CsA or TAC). RESULTS We performed a 3-year analysis of 60 patients. There was no difference in age, gender, or cold ischemic time between two groups, Serum creatinine, urine protein, and blood fat levels of the CsA group were significantly higher than the TAC group (P < .05), while the creatinine clearance was remarkably lower than the TAC group (P < .05). The incidence of tubular atrophy, arteriohyalinosis, and interstitial fibrosis and nephrotoxic lesions among the CsA group were higher than the TAC group, as well as the chronic allograft nephropathy (CAN) Banff score (P < .05). P-gp was predominantly present in the a tubular apical membrane, basal membrane, and cytoplasm. The intensity and extent of tubular staining score in the CsA group were lower compared with the TAC group (P < .01 and P < .05, respectively). CONCLUSION Less P-gp expression in the CsA group than the TAC group may be the molecular action pathway of the high incidence of CsA nephrotoxicity and CsA-induced CAN. This study perhaps unraveled a novel interpretation that the differences of CsA and TAC on long-term allograft survival were due to increases dynamic effects of CsA at the exposures employed in this study.

Low-Site Peritoneal Catheter Implantation Decreases Tip Migration and Omental Wrapping

1. Akashi YJ, Springer J, lainscak M, Anker SD. Atrial natriuretic peptide and related peptides [review]. clin chem lab med 2007; 45:1259–67. 2. Zoccali C, Mallamaci F, Benedetto FA, Tripepi G, Parlongo S, Cataliotti A, et al. Cardiac natriuretic peptides are related to left ventricular mass and function and predict mortality in dialysis patients. J am Soc Nephrol 2001; 12: 1508–15. 3. Wang AY, lam CW, Yu CM, Wang M, Chan Ih, Zhang Y, et al. n-terminal pro-brain natriuretic peptide: an independent risk predictor of cardiovascular congestion, mortality, and adverse cardiovascular outcomes in chronic peritoneal dialysis patients. J am Soc Nephrol 2007; 18:321–30. 4. Martinez-rumayor A, richards AM, Burnett JC, Januzzi Jl Jr. Biology of the natriuretic peptides [review]. am J cardiol 2008; 101(3A):3–8. 5. Wahl hG, Graf S, renz h, Fassbinder W. elimination of the cardiac natriuretic peptides B-type natriuretic peptide (BnP) and n-terminal proBnP by hemodialysis. clin chem 2004; 50:1071–4. 6. Wu Ah, Packer M, Smith A, Bijou r, Fink D, Mair J, et al. Analytical and clinical evaluation of the Bayer ADVIA Centaur automated B-type natriuretic peptide assay in patients with heart failure: a multisite study. clin chem 2004; 50:867–73. 7. Seferian Kr, Tamm nn, Semenov AG, Mukharyamova KS, Tolstaya AA, Koshkina eV, et al. The brain natriuretic peptide (BnP) precursor is the major immunoreactive form of BnP in patients with heart failure. clin chem 2004; 50: 2052–8. 8. niederkofler ee, Kiernan UA, o’rear J, Menon S, Saghir S, Protter AA, et al. Detection of endogenous B-type natriuretic peptide at very low concentrations in patients with heart failure. circ heart Fail 2008; 1:258–64. doi:10.3747/pdi.2008.00279

Effect of coupled plasma filtration adsorption on endothelial cell function in patients with multiple organ dysfunction syndrome

Objective The purpose of our study was to investigate the effect of coupled plasma filtration adsorption (CPFA) on endothelial cell (EC) function in patients with multiple organ dysfunction syndrome (MODS). Methods Besides routine therapy, the 24 MODS patients underwent both CPFA and high volume hemofiltration (HVHF), scheduled randomly at intervals of 12 hours. Patient serum from 0, 5, and 10 hours of therapy was collected to measure soluble E-selectin (sE-selectin) and soluble thrombomodulin (sTM) by the ELISA method. Human umbilical vein endothelial cells (HUVEC) were incubated for 24 hours with the patient serum and the supernatant liquid was gathered to detect sTM and sE-selectin. The proliferation function of the ECs was detected by methyl thiazolyl tetrazolium (MTT) method. Results 1. The serum levels of sE-selectin and sTM were significantly higher in MODS patients than in controls; serum sE-selectin and sTM decreased remarkably after a single circulation in CPFA (p<0. 05) but not in HVHF (p>0. 05); the level of sE-selectin and sTM in systemic circulation had no change during CPFA or HVHF (p>0.05); 2. sTM in supernatant liquid incubated with serum from 5 hours of CPFA and 10 hours of HVHF decreased remarkably (p<0.05), while sE-selectin decreased significantly (p<0. 05) from 10 hours of CPFA, but there was no change from 5 hours and 10 hours of HVHF (p>0. 05); 3. when incubated with serum taken from the device pre- or post-CPFA, the optical density (OD) value of the latter was higher. The OD value increased gradually when incubated with serum from 0, 5, and 10 hours of CPFA (p<0.05), but changed little from HVHF. Conclusions CPFA can eliminate sE-selectin and sTM and improve the secretion function of ECs. CPFA was somewhat better and earlier than HVHF, while to a certain degree it can weaken the inhibitory effect of serum on the proliferation function of ECs.

A vital role for myosin-9 in puromycin aminonucleoside-induced podocyte injury by affecting actin cytoskeleton.

ABSTRACT Podocyte injury is an early pathological change of many kidney diseases. In particular, the actin cytoskeleton plays an important role in maintaining the normal function of podocytes. Disruption of the actin cytoskeleton is a feature of podocyte injury in proteinuric nephropathies. Recent studies showed that myosin-9 was localized in the podocyte foot processes and was necessary in maintaining podocyte structural homeostasis. However, it is unclear whether myosin-9 maintains podocyte structure by affecting actin cytoskleton. Here, the role of myosin-9 in puromycin aminonucleoside (PAN)-induced podocyte injury was explored both in vitro and in vivo. In cultured mouse podocytes (MPC5), it was determined that PAN downregulated myosin-9 expression, disrupted the actin cytoskeleton and reduced the adhesion ability. Reduced myosin-9 expression by siRNA precipitated podocyte cytoskeletal damage and accelerated PAN-induced podocyte detachment. Overexpression of myosin-9 protected against PAN-induced podocyte detachment. Furthermore, administration of an antioxidant Mn(III)tetrakis (4-benzoic acid) porphyrin (MnTBAP) inhibited PAN-induced podocyte cytoskeletal damage and podocyte detachment by restoring the expression of myosin-9. In the rat PAN nephropathy model, MnTBAP could also attenuate PAN-induced reduction of myosin-9 and podocyte loss. Taken together, these findings pinpointed that oxidative stress contributed to PAN-induced podocyte injury through the repression of a cytoskeletal protein myosin-9, which provided novel insights into a potential target for the treatment of podocyte injury-associated glomerulopathies.