Proteomics reveals defective peroxisomal fatty acid oxidation during the progression of acute kidney injury and repair.

Acute kidney injury (AKI) is characterized by a rapid decrease in renal function with high mortality and risk of progression to chronic kidney disease (CKD). Ischemia and reperfusion injury (IRI) is one of the major causes of AKI. However, the cellular and molecular responses of the kidney to IRI are complex and not fully understood. Herein, we conducted unbiased proteomics and bioinformatics analyses in an IRI mouse model on days 3, 7, and 21, and validated the results using IRI, unilateral ureteral obstruction (UUO), and biopsies from patients with AKI or CKD. The results indicated an obvious temporal expression profile of differentially expressed proteins and highlighted impaired lipid metabolism during the progression of AKI to CKD. Acyl-coenzyme A oxidase 1 (Acox1), the first rate-limiting enzyme of peroxisomal fatty acid beta-oxidation, was then selected, and its disturbed expression in the two murine models validated the proteomic findings. Accordingly, Acox1 expression was significantly downregulated in renal biopsies from patients with AKI or CKD, and its expression was negatively correlated with kidney injury score. Furthermore, in contrast to the decreased Acox1 expression, lipid droplet accumulation was remarkably increased in these renal tissues, suggesting dysregulation of fatty acid oxidation. In conclusion, our results suggest that defective peroxisomal fatty acid oxidation might be a common pathological feature in the transition from AKI to CKD, and that Acox1 is a promising intervention target for kidney injury and repair.

Decoy receptor 2 mediates the apoptosis-resistant phenotype of senescent renal tubular cells and accelerates renal fibrosis in diabetic nephropathy.

Apoptotic resistance leads to persistent accumulation of senescent cells and sustained expression of a senescence-associated secretory phenotype, playing an essential role in the progression of tissue fibrosis. However, whether senescent renal tubular epithelial cells (RTECs) exhibit an apoptosis-resistant phenotype, and the role of this phenotype in diabetic nephropathy (DN) remain unclear. Our previous study was the first to demonstrate that decoy receptor 2 (DcR2) is associated with apoptotic resistance in senescent RTECs and renal fibrosis. In this study, we aimed to further explore the mechanism of DcR2 in apoptosis-resistant RTECs and renal fibrosis in DN. DcR2 was co-localized with fibrotic markers (α-SMA, collagen IV, fibronectin), senescent marker p16, and antiapoptotic proteins FLIP and Bcl2 but rarely co-localized with caspase 3 or TUNEL. DcR2 overexpression promoted renal fibrosis in mice with streptozotocin (STZ)-induced DN, as evidenced by augmented Masson staining and upregulated expression of fibrotic markers. DcR2 overexpression also enhanced FLIP expression while reducing the expression of pro-apoptotic proteins (caspases 8 and 3) in senescent RTECs, resulting in apoptotic resistance. In contrast, DcR2 knockdown produced the opposite effects in vitro and in vivo. Moreover, quantitative proteomics and co-immunoprecipitation experiments demonstrated that DcR2 interacted with glucose-related protein 78 kDa (GRP78), which has been shown to promote apoptotic resistance in cancer. GRP78 exhibited co-localization with senescent and antiapoptotic markers but was rarely co-expressed with caspase 3 or TUNEL. Additionally, GRP78 knockdown decreased the apoptosis resistance of HG-induced senescent RTECs with upregulated cleaved caspase 3 and increased the percentage of apoptotic RTECs. Mechanistically, DcR2 mediated apoptotic resistance in senescent RTECs by enhancing GRP78-caspase 7 interactions and promoting Akt phosphorylation. Thus, DcR2 mediated the apoptotic resistance of senescent RTECs and renal fibrosis by interacting with GRP78, indicating that targeting the DcR2-GRP78 axis represents a promising therapeutic strategy for DN.

The nitrate transporter OsNPF7.9 mediates nitrate allocation and the divergent nitrate use efficiency between indica and japonica rice.

Nitrate allocation in Arabidopsis (Arabidopsis thaliana) represents an important mechanism for mediating plant environmental adaptation. However, whether this mechanism occurs or has any physiological/agronomic importance in the ammoniphilic plant rice (Oriza sativa L.) remains unknown. Here, we address this question through functional characterization of the Nitrate transporter 1/Peptide transporter Family (NPF) transporter gene OsNPF7.9. Ectopic expression of OsNPF7.9 in Xenopus oocytes revealed that the gene encodes a low-affinity nitrate transporter. Histochemical and in-situ hybridization assays showed that OsNPF7.9 expresses preferentially in xylem parenchyma cells of vasculature tissues. Transient expression assays indicated that OsNPF7.9 localizes to the plasma membrane. Nitrate allocation from roots to shoots was essentially decreased in osnpf7.9 mutants. Biomass, grain yield, and nitrogen use efficiency (NUE) decreased in the mutant dependent on nitrate availability. Further analysis demonstrated that nitrate allocation mediated by OsNPF7.9 is essential for balancing rice growth and stress tolerance. Moreover, our research identified an indica-japonica divergent single-nucleotide polymorphism occurring in the coding region of OsNPF7.9, which correlates with enhanced nitrate allocation to shoots of indica rice, revealing that divergent nitrate allocation might represent an important component contributing to the divergent NUE between indica and japonica subspecies and was likely selected as a favorable trait during rice breeding.

Relationships among the Dosage of Erythropoiesis-Stimulating Agents, Erythropoietin Resistance Index, and Mortality in Maintenance Hemodialysis Patients.

BACKGROUND: Erythropoiesis-stimulating agents (ESAs) constitute an important treatment option for anemia in hemodialysis (HD) patients. We investigated the relationships among the dosage of ESA, erythropoietin resistance index (ERI) scores, and mortality in Chinese MHD patients. METHODS: This multicenter observational retrospective study included MHD patients from 16 blood purification centers (n = 824) who underwent HD in 2011-2015 and were followed up until December 31, 2016. We collected demographic variables, HD parameters, laboratory values, and ESA dosages. Patients were grouped into quartiles according to ESA dosage to study the effect of ESA dosage on all-cause mortality. The ERI was calculated as follows: ESA (IU/week)/weight (kg)/hemoglobin levels (g/dL). We also compared outcomes among the patients stratified into quartiles according to ERI scores. We used the Cox proportional hazards model to measure the relationships between the ESA dosage, ERI scores, and all-cause mortality. Using propensity score matching, we compared mortality between groups according to ERI scores, classified as either > or ≤12.80. RESULTS: In total, 824 patients were enrolled in the study; 200 (24.3%) all-cause deaths occurred within the observation period. Kaplan-Meier analyses showed that patients administered high dosages of ESAs had significantly worse survival than those administered low dosages of ESAs. A multivariate Cox regression identified that high dosages of ESAs could significantly predict mortality (ESA dosage >10,000.0 IU/week, HR = 1.59, 95% confidence intervals (CIs) (1.04, 2.42), and p = 0.031). Our analysis also indicated a significant increase in the risk of mortality in patients with high ERI scores. Propensity score matching-analyses confirmed that ERI > 12.80 could significantly predict mortality (HR = 1.56, 95% CI [1.11, 2.18], and p = 0.010). CONCLUSIONS: Our data suggested that ESA dosages >10,000.0 IU/week in the first 3 months constitute an independent predictor of all-cause mortality among Chinese MHD patients. A higher degree of resistance to ESA was related to a higher risk of all-cause mortality.

Impaired perfusion in the myocardial microcirculation in asymptomatic patients with Stages 1-4 chronic kidney disease with intrarenal arterial lesions.

BACKGROUND: Even mild renal disease is a powerful cardiovascular risk factor. However, the association between these pathophysiologic processes (especially in the early asymptomatic stage) is not known. METHODS: We recruited 243 asymptomatic patients with Stages 1-4 chronic kidney disease (CKD) without obstructive coronary artery disease (CAD). We distinguished different degrees of severity of intrarenal arterial lesions (IALs) according to the Oxford classification. Myocardial microcirculation perfusion was measured using single-photon emission computed tomography (SPECT). Summed scores of 17 stress and rest image segments produced the summed stress score (SSS) and summed rest score (SRS), respectively. The summed difference score (SDS) was calculated as the difference between the SSS and SRS. Coronary microvascular disease (CMD) was defined as abnormal SPECT (SSS ≥4 or SDS ≥2) in the absence of obstructive CAD. RESULTS: Participants showed a stepwise increase in CMD severity with IAL aggravation. SSS of no/mild/moderate/severe IALs was 1.64 ± 1.08, 2.56 ± 1.35, 4.42 ± 2.17 and 6.48 ± 3.52, respectively (P < 0.05 for all). SDS of no/mild/moderate/severe IALs was 1.29 ± 0.49, 1.75 ± 0.56, 3.06 ± 1.12 and 4.16 ± 1.85, respectively (P < 0.05 for all). The percentage of subclinical CMD in CKD patients with IALs was significantly higher than in those without IALs (69.57% versus 14.71%; P = 0.01). Multiple regression analysis showed that renal arteriolar hyalinization (odds ratio = 1.578, P = 0.009) was associated independently with subclinical CMD. CONCLUSIONS: We demonstrated, for the first time, that impaired perfusion in the myocardial microcirculation in asymptomatic patients with Stages 1-4 CKD with IALs. Renal arteriolar hyalinization may be a useful marker of CMD in CKD.

Efficacy and safety of Shenyankangfu Tablet, a Chinese patent medicine, for primary glomerulonephritis: A multicenter randomized controlled trial.

BACKGROUND: Shenyankangfu Tablet (SYKFT) is a Chinese patent medicine that has been used widely to decrease proteinuria and the progression of chronic kidney disease. OBJECTIVE: This trial compared the efficacy and safety of SYKFT, for the control of proteinuria in primary glomerulonephritis patients, against the standard drug, losartan potassium. DESIGN, SETTING, PARTICIPANTS AND INTERVENTION: This was a multicenter, double-blind, randomized, controlled clinical trial. Primary glomerulonephritis patients, aged 18-70 years, with blood pressure ≤ 140/90 mmHg, estimated glomerular filtration rate (eGFR) ≥ 45 mL/min per 1.73 m2, and 24-hour proteinuria level of 0.5-3.0 g, were recruited in 41 hospitals across 19 provinces in China and were randomly divided into five groups: SYKFT, losartan potassium 50 mg or 100 mg, SYKFT plus losartan potassium 50 mg or 100 mg. MAIN OUTCOME MEASURES: The primary outcome was change in the 24-hour proteinuria level, after 48 weeks of treatment. RESULTS: A total of 735 participants were enrolled. The percent decline of urine protein quantification in the SYKFT group after 48 weeks was 8.78% ± 2.56% (P = 0.006) more than that in the losartan 50 mg group, which was 0.51% ± 2.54% (P = 1.000) less than that in the losartan 100 mg group. Compared with the losartan potassium 50 mg group, the SYKFT plus losartan potassium 50 mg group had a 13.39% ± 2.49% (P < 0.001) greater reduction in urine protein level. Compared with the losartan potassium 100 mg group, the SYKFT plus losartan potassium 100 mg group had a 9.77% ± 2.52% (P = 0.001) greater reduction in urine protein. With a superiority threshold of 15%, neither was statistically significant. eGFR, serum creatinine and serum albumin from the baseline did not change statistically significant. The average change in TCM syndrome score between the patients who took SYKFT (-3.00 [-6.00, -2.00]) and who did not take SYKFT (-2.00 [-5.00, 0]) was statistically significant (P = 0.003). No obvious adverse reactions were observed in any group. CONCLUSION: SYKFT decreased the proteinuria and improved the TCM syndrome scores of primary glomerulonephritis patients, with no change in the rate of decrease in the eGFR. SYKFT plus losartan potassium therapy decreased proteinuria more than losartan potassium therapy alone. TRIAL REGISTRATION NUMBER: NCT02063100 on ClinicalTrials.gov.

Development and Preliminary Validation of a Depression Assessment Tool for Maintenance Hemodialysis Patients.

Patients undergoing maintenance hemodialysis (MHD) are subject to a higher-than-usual prevalence of depressive disorders. However, the lack of consensus regarding the best assessment method remains an important problem. Thus, there is a clear need for more effective screening tools and an easily administered, disease-specific self-report measure of depression in MHD patients. After we developed and administered an initial depression inventory for MHD patients (I-DI-MHD), we created the DI-MHD and administered the DI-MHD and the Beck Depression Inventory (BDI) to 354 patients from four hospitals. Reliability, construct validity and receiver operator characteristic curves were assessed. The 17-item DI-MHD instrument displayed good internal consistency (Cronbach's alpha =0.893), provided excellent convergent validity, and correlated with the BDI scale (kappa =0.785, P <0.001). A factor analysis pattern matrix analysis showed that a four-factor model provided the best account of the data. Finally, the DI-MHD cutoff yielded a sensitivity of 0.97 and a specificity of 0.86, which were slightly better than the corresponding values for the BDI. The DI-MHD scale shows reasonable validity and reliability for assessing depression in MHD patients.

Effects of Niaoduqing Particles () on Delaying Progression of Renal Dysfunction: A Post-trial, Open-Label, Follow-up Study.

OBJECTIVE: To follow up the participants of the randomized clinical trial "Efficacy and Safety of Niaoduqing Particles () for Delaying Moderate-to-Severe Renal Dysfunction", and assess the long-term effects of Niaoduqing Particles on delaying the progression of renal dysfunction. METHODS: Participants, who had previously been randomly assigned to receive Niaoduqing Particles or placebo for 24 weeks (146 cases in each group), were invited to follow-up and all were administered Niaoduqing Particles 5 g thrice daily and 10 g before bedtime for 24 weeks. The primary endpoints were changes in baseline serum creatinine (Scr) and estimated glomerular filtration rate (eGFR) after completion of the open-label treatment period. RESULTS: After the double-blind period, the median (interquartile range) changes in Scr were 1.1 (-13.0-24.1) and 11.7 (-2.6-42.9) µmol/L for the Niaoduqing Particle and placebo groups, respectively (P=0.008), and the median changes in eGFRs were-0.2 (-4.3-2.7) and-2.21 (-5.7-0.8) mL•min-1•1.73 m-2, respectively (P=0.016). There were significant differences in the double-blind period changes in renal function between groups. After the open-label period, the median changes in Scr were 9.0 (-10.0-41.9) and 17.5 (-6.0-50.0) µmol/L for the Niaoduqing Particle and placebo groups according to baseline grouping, respectively (P=0.214), and the median changes in eGFRs were-2.3 (-6.4-1.9) and-3.7 (-7.5-1.1) mL•min-1•1.73 m-2, respectively (P=0.134). There were no statistical differences in the open-label period changes in renal function between groups. The eGFR reduction of participants who accepted Niaoduqing Particle treatment for 48 weeks was projected to 2.5 mL•min-1•1.73 m-2 per year. CONCLUSION: Niaoduqing Particles appear to have long-term efficacy for patients with moderate-to-severe renal dysfunction. Although there was no statistical difference, the early use of Niaoduqing Paticles seems to ameliorate the worsening of renal function. (Trial registration No. ChiCTR-TRC-12002448).

Safety, Effectiveness, and Manipulability of Peritoneal Dialysis Machines Made in China: A Randomized, Crossover, Multicenter Clinical Study.

BACKGROUND: Automated peritoneal dialysis (APD) can cater to individual needs, provide treatment while asleep, take into account the adequacy of dialysis, and improve the quality of life. Currently, independent research and development of APD machines made in China are more conducive to patients. A randomized, multicenter, crossover study was conducted by comparing an APD machine made in China with an imported machine. The safety, effectiveness, and manipulability of the two machines were compared. METHODS: Two hundred and sixty patients who underwent peritoneal dialysis (PD) on a regular basis in 18 centers between August 2015 and February 2016 were included. The inclusion criteria include age ≥18 years and PD ≥30 days. The exclusion criteria were as follows: hemodialysis; exit site or tunnel infection; and peritonitis ≤30 days. The patients were randomly divided into Group A, who were first treated with a FM machine made in China, then changed to an imported machine; and Group B, who were treated using the reverse sequence. APD treatment was performed with 10 L/10 h and 5 cycles of exchange. After 72 h, the daily peritoneal Kt/V, the accuracy of the injection rate, accuracy of the injection temperature, safety, and manipulability of the machine were assessed. Noninferiority test was conducted between the two groups. RESULTS: The daily peritoneal Kt/V in the APD machine made in China and the imported APD machine were 0.17 (0.14, 0.25) and 0.16 (0.13, 0.23), respectively. There was no significant difference between the groups (Z = 0.15, P = 0.703). The lower limit of the daily Kt/V difference between the two groups was 0.0069, which was greater than the noninferiority value of -0.07 in this study. The accuracy of the injection rate and injection temperature was 89.7% and 91.5%, respectively, in the domestic APD machine, which were both slightly better than the accuracy rates of 84.0% and 86.8% in the imported APD machine (89.7% vs. 84.0%, P = 0.2466; 91.5% vs. 86.8%, P = 0.0954). Therefore, the APD machine made in China was not inferior to the imported APD machine. The fuselage of the imported APD machine was space-saving, while the APD machine made in China was superior with respect to body mobility, man-machine dialog operation, alarm control, and patient information recognition. CONCLUSIONS: The FM machine made in China was not inferior to the imported APD machine. In addition, the FM machine made in China had better operability. TRIAL REGISTRATION: Clinicaltrials.gov, NCT02525497; https://clinicaltrials.gov/ct2/results?cond=&term=NCT02525497&cntry=& state=&city=&dist=.

[Primary culture and identification of mouse renal proximal tubular epithelial cells].

The present study was aimed to establish a modified method for culturing mouse renal proximal tubular epithelial cells (TECs). Renal cortex was isolated from mouse kidney and scissored into pieces. TECs were separated by digesting scissored renal cortex in type II collagenase combined with strainer filtration, and then cultured in DMEM. The morphology of TECs was observed under inverted microscopy. The cell proliferative ability was assessed by flow cytometry, and cell viability was analyzed by CCK-8 assay. The purity of TECs was identified by immunofluorescence. Immunofluorescence observation showed that more than 95% cells were epithelial marker CK18 positive and more than 90% cells expressed renal proximal TECs marker proteins, Villin, AQP1, and SGLT2. The cells could be subcultured for about 5 times. The cell proliferative ability declined following the repeated passage. This study introduced a modified efficient method for culturing highly purified mouse renal proximal TECs.

High-dose HOOK effect in urinary DcR2 assay in patients with chronic kidney disease.

BACKGROUND: Urinary DcR2 (uDcR2) is a biomarker for the early detection the tubulointerstitial injury (TII) in patients with chronic kidney disease (CKD), but the high-dose hook effect may lead to falsely low or even negative results when using an enzyme-linked immunosorbent assay (ELISA). This study aimed to investigate if the high-dose hook effect exists with ELISA testing, and to uncover a potential approach for reducing this effect. METHODS: 72 CKD patients were recruited and categorized into four groups based on TII scores. uDcR2 was measured in undiluted and serially diluted (two-, four-, eight- and 16-fold dilutions) urine using an ELISA kit. The results from the assay were normalized to urinary creatinine. We evaluated the correlation between uDcR2/cre levels at different dilutions and renal histological parameters. Receiver operating characteristic (ROC) curves were generated to examine the value of uDcR2/cre for predicting TII. RESULTS: uDcR2/cre levels in the undiluted urine were significantly higher in patients with CKD than those in the control. However, higher TII scores did not yield higher levels of uDcR2/cre in the undiluted urine. After serial dilution, uDcR2/cre levels were highest with the four-fold dilution. A positive correlation was found between uDcR2/cre levels at different dilutions and TII scores, with the highest correlation coefficient and the largest AUC being observed at the four-fold dilution. CONCLUSIONS: The high-dose hook effect was apparent during ELISA testing of uDcR2 in CKD patients, yet dilution of the urine samples neutralized this effect. However, the use of a four-fold dilution of urine for uDcR2/cre testing may eliminate the high-dose hook effect and make it possible to effectively monitor the severity of TII in CKD patients.

Efficacy and Safety of Niaoduqing Particles for Delaying Moderate-to-severe Renal Dysfunction: A Randomized, Double-blind, Placebo-controlled, Multicenter Clinical Study.

BACKGROUND: Chronic kidney disease (CKD) with moderate-to-severe renal dysfunction usually exhibits an irreversible course, and available treatments for delaying the progression to end-stage renal disease are limited. This study aimed to assess the efficacy and safety of the traditional Chinese medicine, Niaoduqing particles, for delaying renal dysfunction in patients with stage 3b-4 CKD. METHODS: The present study was a prospective, randomized, double-blind, placebo-controlled, multicenter clinical trial. From May 2013 to December 2013, 300 CKD patients with an estimated glomerular filtration rate (eGFR) between 20 and 45 ml·min-1·1.73 m-2, aged 18-70 years were recruited from 22 hospitals in 11 Chinese provinces. Patients were randomized in a 1:1 ratio to either a test group, which was administered Niaoduqing particles 5 g thrice daily and 10 g before bedtime for 24 weeks, or a control group, which was administered a placebo using the same methods. The primary endpoints were changes in baseline serum creatinine (Scr) and eGFR after completion of treatment. The primary endpoints were analyzed using Student's t-test or Wilcoxon's rank-sum test. The present study reported results based on an intention-to-treat (ITT) analysis. RESULTS: A total of 292 participants underwent the ITT analysis. At 24 weeks, the median (interquartile range) change in Scr was 1.1 (-13.0-24.1) and 11.7 (-2.6-42.9) µmol/L for the test and control groups, respectively (Z = 2.642, P = 0.008), and the median change in eGFR was -0.2 (-4.3-2.7) and -2.2 (-5.7-0.8) ml·min-1·1.73 m-2, respectively (Z = -2.408, P = 0.016). There were no significant differences in adverse events between the groups. CONCLUSIONS: Niaoduqing particles safely and effectively delayed CKD progression in patients with stage 3b-4 CKD. This traditional Chinese medicine may be a promising alternative medication for patients with moderate-to-severe renal dysfunction. TRIAL REGISTRATION: Chinese Clinical Trial Register, ChiCTR-TRC-12002448; http://www.chictr.org.cn/showproj.aspx?proj=7102.

Tonoplast-localized nitrate uptake transporters involved in vacuolar nitrate efflux and reallocation in Arabidopsis.

A great proportion of nitrate taken up by plants is stored in vacuoles. Vacuolar nitrate accumulation and release is of great importance to nitrate reallocation and efficient utilization. However, how plants mediate nitrate efflux from vacuoles to cytoplasm is largely unknown. The current study identified NPF5.11, NPF5.12 and NPF5.16 as vacuolar nitrate efflux transporters in Arabidopsis. Histochemical analysis showed that NPF5.11, NPF5.12 and NPF5.16 were expressed preferentially in root pericycle cells and xylem parenchyma cells, and further analysis showed that these proteins were tonoplast-localized. Functional characterization using cRNA-injected Xenopus laevis oocytes showed that NPF5.11, NPF5.12 and NPF5.16 were low-affinity, pH-dependent nitrate uptake transporters. In npf5.11 npf5.12 npf5.16 triple mutant lines, more root-fed 15NO3- was translocated to shoots compared to the wild type control. In the NPF5.12 overexpression lines, proportionally less nitrate was maintained in roots. These data together suggested that NPF5.11, NPF5.12 and NPF5.16 might function to uptake nitrate from vacuoles into cytosol, thus serving as important players to modulate nitrate allocation between roots and shoots.

Isolation and identification of senescent renal tubular epithelial cells using immunomagnetic beads based on DcR2.

Cell senescence plays a major role in the progression of tumors and chronic conditions such as diabetes and chronic kidney disease. Senescent cells are an important model for the study of aging-related diseases, and there is currently no efficient method for sorting out senescent cells. Decoy receptor 2 (DcR2) is a transmembrane receptor of the tumor necrosis factor superfamily, which is specifically expressed in senescent cells. In this study, we used magnetic activated cell sorting (MACS) isolation of a highly-pure populations DcR2-positive renal tubular epithelial cells (RTECs) based on three senescent cell models including the fifth passage cells, advanced glycation end-products (AGEs)- and H2O2-induced cells. The percentages of DcR2 positive RTECs in G1 and S phases increased by 20% and 4%, respectively, as compared to that in the pre-sorted cells. The positivity rates of SA-ß-gal, p16, and senescence-associated heterochromatin foci (SAHF) in DcR2-positive RTECs were about 40%, 30%, and 44% higher than that prior to cell sorting. The levels of IL-6 and TGF-ß1 in the supernatant were increased by 1.7 and 1.5 folds, respectively, as compared to that observed prior to sorting. No significant cell death was observed after 5days of continuous culture. Ki-67 positive expression rate in DcR2 negative RTECs was significantly higher than that in DcR2 positive RTECs after MACS. We demonstrated the use of DcR2 to classify live, senescent RTECs with a high specificity and stability. Our findings lay the foundation for further study of senescent RTECs in the progression of chronic kidney disease.

Peritoneal dialysis reduces amyloid-beta plasma levels in humans and attenuates Alzheimer-associated phenotypes in an APP/PS1 mouse model.

Clearance of amyloid-beta (Aß) from the brain is an important therapeutic strategy for Alzheimer's disease (AD). Current studies mainly focus on the central approach of Aß clearance by introducing therapeutic agents into the brain. In a previous study, we found that peripheral tissues and organs play important roles in clearing brain-derived Aß, suggesting that the peripheral approach of removing Aß from the blood may also be effective for AD therapy. Here, we investigated whether peritoneal dialysis, a clinically available therapeutic method for chronic kidney disease (CKD), reduces brain Aß burden and attenuates AD-type pathologies and cognitive impairments. Thirty patients with newly diagnosed CKD were enrolled. The plasma Aß concentrations of the patients were measured before and after peritoneal dialysis. APP/PS1 mice were subjected to peritoneal dialysis once a day for 1 month from 6 months of age (prevention study) or 9 months of age (treatment study). The Aß in the interstitial fluid (ISF) was collected using microdialysis. Behavioural performance, long-term potentiation (LTP), Aß burden and other AD-type pathologies were measured after 1 month of peritoneal dialysis. Peritoneal dialysis significantly reduced plasma Aß levels in both CKD patients and APP/PS1 mice. Aß levels in the brain ISF of APP/PS1 mice immediately decreased after reduction of Aß in the blood during peritoneal dialysis. In both prevention and treatment studies, peritoneal dialysis substantially reduced Aß deposition, attenuated other AD-type pathologies, including Tau hyperphosphorylation, glial activation, neuroinflammation, neuronal loss, and synaptic dysfunction, and rescued the behavioural deficits of APPswe/PS1 mice. Importantly, the Aß phagocytosis function of microglia was enhanced in APP/PS1 mice after peritoneal dialysis. Our study suggests that peritoneal dialysis is a promising therapeutic method for AD, and Aß clearance using a peripheral approach could be a desirable therapeutic strategy for AD.

Analysis of Factors Associated with Death in Maintenance Hemodialysis Patients: A Multicenter Study in China.

BACKGROUND: Patients on hemodialysis have a high-mortality risk. This study analyzed factors associated with death in patients on maintenance hemodialysis (MHD). While some studies used baseline data of MHD patients, this study used the most recent data obtained from patients just prior to either a primary endpoint or the end of the study period to find the characteristics of patients preceding death. METHODS: Participants were selected from 16 blood purification centers in China from January 2012 to December 2014. Patients' data were collected retrospectively. Based on survival status, the participants were divided into two groups: survival group and the death group. Logistic regression analysis was performed to determine factors associated with all-cause mortality. RESULTS: In total, 4104 patients (57.58% male, median age 59 years) were included. Compared with the survival group, the death group had more men and more patients with diabetic nephropathy (DN) and hypertensive nephropathy. The patients preceding death also had lower levels of diastolic blood pressure, hemoglobin, serum albumin, serum calcium, serum phosphate, Kt/V, and higher age. Multivariate analysis revealed that male sex (odd ratio [OR]: 1.437, 95% confidence interval [CI]: 1.094-1.886), age (OR: 1.046, 95% CI: 1.036-1.057), and presence of DN (OR: 1.837, 95% CI: 1.322-2.552) were the risk factors associated with mortality. High serum calcium (OR: 0.585, 95% CI: 0.346-0.989), hemoglobin (OR: 0.974, 95% CI: 0.967-0.981), albumin (OR: 0.939, 95% CI: 0.915-0.963) levels, and dialysis with noncuffed catheter (OR: 0.165, 95% CI: 0.070-0.386) were protective factors based on a multivariate analysis. CONCLUSIONS: Hemodialysis patients preceding death had lower hemoglobin, albumin, and serum calcium levels. Multivariate analysis showed that male sex, age, DN, low hemoglobin, low albumin, and low serum calcium were associated with death in hemodialysis patients.

Urinary DcR2 is a novel biomarker for tubulointerstitial injury in patients with diabetic nephropathy.

Tubulointerstitial injury (TII) plays a crucial role in the progression of diabetic nephropathy (DN), but lack of specific and sensitive biomarkers for monitoring TII in DN management. This study is to investigate whether urinary decoy receptor 2 (uDcR2) could serve as a novel noninvasive biomarker for assessing TII in DN. We recruited 311 type 2 diabetics and 139 DN patients who were diagnosed by renal biopsy. uDcR2 levels were measured by ELISA, and renal DcR2 expression was detected immunohistochemically. Associations between uDcR2 and renal DcR2 and renal functional parameters were evaluated. Receiver operating characteristics (ROC) curve analyzed area under the curve (AUC) of uDcR2 for assessing TII. Double staining was undertaken for renal DcR2 with proximal and distal tubular markers; senescent markers p16, p21, and senescence-associated ß-galactosidase (SA-ß-gal); and fibrotic markers collagen I and IV. We found DcR2 was primarily expressed in renal proximal tubules; uDcR2 levels were elevated per albuminuria stratum and correlated with renal functional parameters in diabetics and were associated with percentage of tubular DcR2 and TII score in DN. The uDcR2 had an AUC of 0.909 for assessing TII in DN by ROC analysis. Almost all tubular DcR2 was coexpressed with p16 and p21, and nearly more than one-half of tubular DcR2 was positive for SA-ß-gal, primarily in collagen I- and IV-positive regions of DN. Our results indicate uDcR2 could potentially serve as a novel biomarker for TII and may reflect senescence of renal proximal tubular cells in DN pathogenesis.

Pure white-light and colour-tuning of Eu(3+)-Gd(3+)-containing metallopolymer.

Direct white-light (CIE coordinate of x = 0.333, y = 0.335, CCT of 5455 K and CRI of 82) with a high luminous efficiency (18.4%) was achieved in the first example of Eu(3+)-Gd(3+)-containing metallopolymer Poly(2-co-NVK-co-4), which also showed tunable purplish-blue to white to yellow-green photoluminescence.

Arabidopsis NRT1.5 Mediates the Suppression of Nitrate Starvation-Induced Leaf Senescence by Modulating Foliar Potassium Level.

Nitrogen deficiency induces leaf senescence. However, whether or how nitrate might affect this process remains to be investigated. Here, we report an interesting finding that nitrate-instead of nitrogen-starvation induced early leaf senescence in nrt1.5 mutant, and present genetic and physiological data demonstrating that nitrate starvation-induced leaf senescence is suppressed by NRT1.5. NRT1.5 suppresses the senescence process dependent on its function from roots, but not the nitrate transport function. Further analyses using nrt1.5 single and nia1 nia2 nrt1.5-4 triple mutant showed a negative correlation between nitrate concentration and senescence rate in leaves. Moreover, when exposed to nitrate starvation, foliar potassium level decreased in nrt1.5, but adding potassium could essentially restore the early leaf senescence phenotype of nrt1.5 plants. Nitrate starvation also downregulated the expression of HAK5, RAP2.11, and ANN1 in nrt1.5 roots, and appeared to alter potassium level in xylem sap from nrt1.5. These data suggest that NRT1.5 likely perceives nitrate starvation-derived signals to prevent leaf senescence by facilitating foliar potassium accumulation.

Impact of ER stress-regulated ATF4/p16 signaling on the premature senescence of renal tubular epithelial cells in diabetic nephropathy.

Premature senescence is an important event during diabetic nephropathy (DN) progression. Here, we investigated the role of endoplasmic reticulum (ER) stress-regulated activation of transcription factor 4 (ATF4)/p16 signaling in the premature senescence of renal tubular epithelial cells (RTECs) during DN development. In the renal tissues of Type 2 DN patients, we detected an increased number of senescent cells; elevated deposition of advanced glycation end products (AGEs); upregulated expression of ER stress marker, glucose-regulated protein 78; as well as overexpression of ATF4 and p16. Similarly, these phenomena were also observed in cultured mouse RTECs following AGE treatment. Interestingly, AGE-induced p16 expression and premature senescence were successfully attenuated by ER stress inhibitor and ATF4 gene silencing. Moreover, AGE-induced premature senescence was mimicked by ER stress inducers and ATF4 overexpression, while suppressed by p16 gene silencing. In addition, ER stress inducers can augment ATF4 expression. Therefore, our results demonstrate that the ER stress-regulated ATF4/p16 pathway is involved in the premature senescence of RTECs during DN progression.