SMN haploinsufficiency promotes ischemia/ reperfusion-induced AKI-to-CKD transition by endoplasmic reticulum stress activation.

Acute kidney injury (AKI) and chronic kidney disease (CKD) are interconnected syndromes that represent a global public health challenge. Here, we identified a specific role of survival of motor neuron (SMN) in ischemia/reperfusion (I/R)-induced kidney injury and progression of CKD. SMN was an essential protein in all cell type and was reported to play important roles in multiple fundamental cellular homeostatic pathways. However, the function of SMN in experimental models of I/R-induced kidney fibrosis has not extensively studied. Genetic ablation of SMN or small interfering RNA-base knockdown of SMN expression aggravated the tubular injury and interstitial fibrosis. Administration of scAAV9-CB-SMN or epithelial cell overexpression of SMN reduced I/R-induced kidney dysfunction and attenuated AKI-to-CKD transition, indicating that SMN is vital for the preservation and recovery of tubular phenotype. Our data showed that the endoplasmic reticulum stress (ERS) induced by I/R was persistent and became progressively more severe in the kidney without SMN. On the contrary, overexpression of SMN prevented against I/R-induced ERS and tubular cell damage. In summary, our data collectively substantiate a critical role of SMN in regulating the ERS activation and phenotype of AKI-to-CKD transition that may contribute to renal pathology during injury and repair.

ASH2L Controls Ureteric Bud Morphogenesis through the Regulation of RET/GFRA1 Signaling Activity in a Mouse Model.

SIGNIFICANCE STATEMENT: Causes of congenital anomalies of the kidney and urinary tract (CAKUT) remain unclear. The authors investigated whether and how inactivation of Ash2l -which encodes a subunit of the COMPASS methyltransferase responsible for genome-wide histone H3 lysine K4 (H3K4) methylation-might contribute to CAKUT. In a mouse model, inactivation of Ash2l in the ureteric bud (UB) lineage led to CAKUT-like phenotypes. Removal of ASH2L led to deficient H3K4 trimethylation, which slowed cell proliferation at the UB tip, delaying budding and impairing branching morphogenesis. The absence of ASH2L also downregulated the expression of Ret , Gfra1 , and Wnt11 genes involved in RET/GFRA1 signaling. These findings identify ASH2L-mediated H3K4 methylation as an upstream epigenetic regulator of signaling crucial for UB morphogenesis and indicate that deficiency or dysregulation of these processes may lead to CAKUT. BACKGROUND: Ureteric bud (UB) induction and branching morphogenesis are fundamental to the establishment of the renal architecture and are key determinants of nephron number. Defective UB morphogenesis could give rise to a spectrum of malformations associated with congenital anomalies of the kidney and urinary tract (CAKUT). Signaling involving glial cell line-derived neurotrophic factor and its receptor rearranged during transfection (RET) and coreceptor GFRA1 seems to be particularly important in UB development. Recent epigenome profiling studies have uncovered dynamic changes of histone H3 lysine K4 (H3K4) methylation during metanephros development, and dysregulated H3K4 methylation has been associated with a syndromic human CAKUT. METHODS: To investigate whether and how inactivation of Ash2l , which encodes a subunit of the COMPASS methyltransferase responsible for genome-wide H3K4 methylation, might contribute to CAKUT, we inactivated Ash2l specifically from the UB lineage in C57BL/6 mice and examined the effects on genome-wide H3K4 methylation and metanephros development. Genes and epigenome changes potentially involved in these effects were screened using RNA-seq combined with Cleavage Under Targets and Tagmentation sequencing. RESULTS: UB-specific inactivation of Ash2l caused CAKUT-like phenotypes mainly involving renal dysplasia at birth, which were associated with deficient H3K4 trimethylation. Ash2l inactivation slowed proliferation of cells at the UB tip, delaying budding and impairing UB branching morphogenesis. These effects were associated with downregulation of Ret , Gfra1 , and Wnt11 , which participate in RET/GFRA1 signaling. CONCLUSIONS: These experiments identify ASH2L-dependent H3K4 methylation in the UB lineage as an upstream epigenetic regulator of RET/GFRA1 signaling in UB morphogenesis, which, if deficient, may lead to CAKUT.

Genome-Wide Association Analysis of Protein-Coding Variants in IgA Nephropathy.

SIGNIFICANCE STATEMENT: Genome-wide association studies have identified nearly 20 IgA nephropathy susceptibility loci. However, most nonsynonymous coding variants, particularly ones that occur rarely or at a low frequency, have not been well investigated. The authors performed a chip-based association study of IgA nephropathy in 8529 patients with the disorder and 23,224 controls. They identified a rare variant in the gene encoding vascular endothelial growth factor A (VEGFA) that was significantly associated with a two-fold increased risk of IgA nephropathy, which was further confirmed by sequencing analysis. They also identified a novel common variant in PKD1L3 that was significantly associated with lower haptoglobin protein levels. This study, which was well-powered to detect low-frequency variants with moderate to large effect sizes, helps expand our understanding of the genetic basis of IgA nephropathy susceptibility. BACKGROUND: Genome-wide association studies have identified nearly 20 susceptibility loci for IgA nephropathy. However, most nonsynonymous coding variants, particularly those occurring rarely or at a low frequency, have not been well investigated. METHODS: We performed a three-stage exome chip-based association study of coding variants in 8529 patients with IgA nephropathy and 23,224 controls, all of Han Chinese ancestry. Sequencing analysis was conducted to investigate rare coding variants that were not covered by the exome chip. We used molecular dynamic simulation to characterize the effects of mutations of VEGFA on the protein's structure and function. We also explored the relationship between the identified variants and the risk of disease progression. RESULTS: We discovered a novel rare nonsynonymous risk variant in VEGFA (odds ratio, 1.97; 95% confidence interval [95% CI], 1.61 to 2.41; P = 3.61×10 -11 ). Further sequencing of VEGFA revealed twice as many carriers of other rare variants in 2148 cases compared with 2732 controls. We also identified a common nonsynonymous risk variant in PKD1L3 (odds ratio, 1.16; 95% CI, 1.11 to 1.21; P = 1.43×10 -11 ), which was associated with lower haptoglobin protein levels. The rare VEGFA mutation could cause a conformational change and increase the binding affinity of VEGFA to its receptors. Furthermore, this variant was associated with the increased risk of kidney disease progression in IgA nephropathy (hazard ratio, 2.99; 95% CI, 1.09 to 8.21; P = 0.03). CONCLUSIONS: Our study identified two novel risk variants for IgA nephropathy in VEGFA and PKD1L3 and helps expand our understanding of the genetic basis of IgA nephropathy susceptibility.

A novel role of BK potassium channel activity in preventing the development of kidney fibrosis.

Kidney fibrosis is a common characteristic of chronic kidney disease and while the large conductance voltage and calcium-activated potassium channel (BK) is widely expressed in kidneys, its role in kidney fibrosis is unknown. To evaluate this, we found that BK protein expression was decreased in the fibrotic kidneys. Accompanying this was increased fibrotic marker protein expression of fibronectin, vimentin and α-smooth muscle actin and increased mRNA expressions of fibronectin, α-smooth muscle actin, collagen III and collagen I. These changes occurred in the unilateral ureteral obstruction and folic acid models of fibrosis and were more pronounced in BK knockout than in wild-type mice. Activation of BK activity by chemical NS1619 or BMS191011 channel openers attenuated kidney fibrosis in these two models while protecting kidney function in wild-type mice. BK deficiency up-regulated transforming growth factor-ß (TGF-ß)/transcription factor Smad2/3 signaling in the fibrotic kidney, whereas activation of BK activity inhibited this signaling pathway both in vivo and in vitro. BK channel activation increased the degradation of TGF-ß receptors induced by TGF-ß1 in vivo and in vitro. Furthermore, in cell lines HK-2, NRK49, and NRK-52E, BK channel activation by NS1619 led to increased caveolae formation and facilitated localization of TGF-ß receptors in the microdomains of lipid rafts. Thus, our data demonstrated that BK activation has an anti-fibrotic effect on kidney fibrosis by inhibiting the TGF-ß signaling pathway through accelerating TGF-ß receptor degradation via the caveolae route. Hence, our study provides innovative insight into BK as a potential therapeutic target for the treatment of kidney fibrosis.

Roxadustat Treatment for Anemia in Patients Undergoing Long-Term Dialysis.

BACKGROUND: Roxadustat is an oral hypoxia-inducible factor prolyl hydroxylase inhibitor that stimulates erythropoiesis and regulates iron metabolism. Additional data are needed regarding the effectiveness and safety of roxadustat as compared with standard therapy (epoetin alfa) for the treatment of anemia in patients undergoing dialysis. METHODS: In a trial conducted in China, we randomly assigned (in a 2:1 ratio) patients who had been undergoing dialysis and erythropoiesis-stimulating agent therapy with epoetin alfa for at least 6 weeks to receive roxadustat or epoetin alfa three times per week for 26 weeks. Parenteral iron was withheld except as rescue therapy. The primary end point was the mean change in hemoglobin level from baseline to the average level during weeks 23 through 27. Noninferiority of roxadustat would be established if the lower boundary of the two-sided 95% confidence interval for the difference between the values in the roxadustat group and epoetin alfa group was greater than or equal to -1.0 g per deciliter. Patients in each group had doses adjusted to reach a hemoglobin level of 10.0 to 12.0 g per deciliter. Safety was assessed by analysis of adverse events and clinical laboratory values. RESULTS: A total of 305 patients underwent randomization (204 in the roxadustat group and 101 in the epoetin alfa group), and 256 patients (162 and 94, respectively) completed the 26-week treatment period. The mean baseline hemoglobin level was 10.4 g per deciliter. Roxadustat led to a numerically greater mean (±SD) change in hemoglobin level from baseline to weeks 23 through 27 (0.7±1.1 g per deciliter) than epoetin alfa (0.5±1.0 g per deciliter) and was statistically noninferior (difference, 0.2±1.2 g per deciliter; 95% confidence interval [CI], -0.02 to 0.5). As compared with epoetin alfa, roxadustat increased the transferrin level (difference, 0.43 g per liter; 95% CI, 0.32 to 0.53), maintained the serum iron level (difference, 25 µg per deciliter; 95% CI, 17 to 33), and attenuated decreases in the transferrin saturation (difference, 4.2 percentage points; 95% CI, 1.5 to 6.9). At week 27, the decrease in total cholesterol was greater with roxadustat than with epoetin alfa (difference, -22 mg per deciliter; 95% CI, -29 to -16), as was the decrease in low-density lipoprotein cholesterol (difference, -18 mg per deciliter; 95% CI, -23 to -13). Roxadustat was associated with a mean reduction in hepcidin of 30.2 ng per milliliter (95% CI, -64.8 to -13.6), as compared with 2.3 ng per milliliter (95% CI, -51.6 to 6.2) in the epoetin alfa group. Hyperkalemia and upper respiratory infection occurred at a higher frequency in the roxadustat group, and hypertension occurred at a higher frequency in the epoetin alfa group. CONCLUSIONS: Oral roxadustat was noninferior to parenteral epoetin alfa as therapy for anemia in Chinese patients undergoing dialysis. (Funded by FibroGen and FibroGen [China] Medical Technology Development; ClinicalTrials.gov number, NCT02652806.).

Hemoperfusion in Maintenance Hemodialysis Patients.

The accumulation of protein-bound uremic toxins and medium-large molecule toxins in maintenance hemodialysis (MHD) patients is one of the causes of long-term dialysis-related complications. Hemoperfusion can remove these uremic toxins and reduce the complications of MHD patients. Upon a review of the Chinese and international literature, combined with practical experience of clinical diagnosis and treatment, the Shanghai Medical Association Society of Nephrology reached a consensus on the clinical applications of hemoperfusion in MHD patients. This consensus included four aspects: selection of appropriate patients, treatment frequency, treatment methods, and adverse reactions and precautions and provided guidelines for the rational and standardized treatment of hemoperfusion in MHD patients.

Randomized Control Study on Hemoperfusion Combined with Hemodialysis versus Standard Hemodialysis: Effects on Middle-Molecular-Weight Toxins and Uremic Pruritus.

INTRODUCTION: Classic hemodialysis schedules present inadequate middle-molecular-weight toxin clearance due to limitations of membrane-based separation processes. Accumulation of uremic retention solutes may result in specific symptoms (e.g., pruritus) and may affect clinical outcome and patient's quality of life. Hemoperfusion (HP) is a blood purification modality based on adsorption that can overcome such limitations, and thus, it may be interesting to test the efficacy of at least one session per week of HP combined with hemodialysis. This is a randomized, open-label trial, controlled, multicenter clinical study to investigate the effect of long-term HP combined with hemodialysis on middle-molecular-weight toxins and uremic pruritus in maintenance hemodialysis (MHD) patients. METHODS: 438 MHD patients from 37 HD centers in China with end-stage kidney disease (63.9% males, mean age 51 years) suffering from chronic intractable pruritus were enrolled in the study. Eligible patients were randomized into four groups: low-flux hemodialysis (LFHD), high-flux hemodialysis (HFHD), HP + LFHD, and HP + HFHD at a 1:1:1:1 ratio. Beta-2 microglobulin (ß2M) and parathyroid hormone (PTH) were measured at baseline, 3-6, and 12 months. At the same time points, the pruritus score was evaluated. The primary outcome was the reduction of ß2M and PTH, while the secondary outcome was the reduction of the pruritus score. RESULTS: In the two groups HP + LFHD and HP + HFHD, there was a significant decrease of ß2M and PTH levels after 12 months compared to the control groups. No significant differences were noted between HP + LFHD and HP + HFHD. Pruritus score reduction was 63% in the HP + LFHD group and 51% in the HP + HFHD group, respectively. CONCLUSION: The long-term HP + HD can reduce ß2M and PTH levels and improve pruritus in MHD patients independently on the use of high- or low-flux dialyzers, showing that the results are linked to the effect of adsorption.

Decreased KLHL3 expression is involved in the activation of WNK-OSR1/SPAK-NCC cascade in type 1 diabetic mice.

Familial hyperkalemic hypertension (FHHt; also called pseudohypoaldosteronism type II) is a hereditary hypertensive disease which can be caused by mutations in four genes: WNK1 [with no lysine (K) 1], WNK4, Kelch-like3 (KLHL3), and cullin3 (CUL3). Decreased KLHL3 expression was identified as being involved in the pathogenesis of FHHt caused by cullin 3 disease mutations. Recent studies have revealed an increased WNK4 and hence Na-Cl cotransporter (NCC) activity in the db/db mice, resulting from PKC-mediated KLHL3 phosphorylation, which impairs the degradation of its substrate, WNK4. However, whether WNK4 and NCC were activated in type 1 diabetes still remains unclear. We created streptozotocin-induced type 1 diabetic mice and revealed that renal WNK-oxidative stress response kinase-1/STE20/SPS1-related proline alanine-rich kinase (OSR1/SPAK)-NCC cascade was activated, whereas KLHL3 expression was markedly decreased and CUL3 was heavily neddylated. Moreover, decreased KLHL3 was reversed and WNK1 and WNK4 abundance increased by MLN4924, a neddylation inhibitor. In vitro, our study also showed decreased KLHL3 abundance without any significant change in phosphorylated KLHL3 under high glucose exposure. These results indicate that decreased KLHL3 likely plays a role in the pathogenesis of renal sodium reabsorption in hyperglycemic conditions.

Efficacy and safety of a selective URAT1 inhibitor SHR4640 in Chinese subjects with hyperuricaemia: a randomized controlled phase II study.

OBJECTIVE: To evaluate the efficacy and safety of SHR4640, a highly selective urate transporter 1 inhibitor, in Chinese subjects with hyperuricaemia. METHODS: This was a randomized double-blind dose-ranging phase II study. Subjects whose serum uric acid (sUA) levels were ≥480 µmol/l with gout, ≥480 µmol/l without gout but with comorbidities, or ≥540 µmol/l were enrolled. Subjects were randomly assigned (1:1:1:1:1) to receive once daily 2.5 mg, 5 mg, 10 mg of SHR4640, 50 mg of benzbromarone or placebo, respectively. The primary end point was the proportion of subjects who achieved target sUA level of ≤360 µmol/l at week 5. RESULTS: 99.5% of subjects (n = 197) were male and 95.9% of subjects had gout history. The proportions of subjects who achieved target sUA at week 5 were 32.5%, 72.5% and 61.5% in the 5 mg, 10 mg SHR4640 and benzbromarone groups, respectively, significantly higher than the placebo group (0%; P < 0.05 for 5 mg and 10 mg SHR4640 group). The sUA was reduced by 32.7%, 46.8% and 41.8% at week 5 with 5 mg, 10 mg SHR4640 and benzbromarone, respectively, vs placebo (5.9%; P < 0.001 for each comparison). The incidences of gout flares requiring intervention were similar among all groups. Occurrences of treatment-emergent adverse events (TEAEs) were comparable across all groups, and serious TEAEs were not reported. CONCLUSIONS: The present study indicated a superior sUA-lowering effect and well tolerated safety profile after 5-week treatment with once-daily 5 mg/10 mg of SHR4640 as compared with placebo in Chinese subjects with hyperuricaemia. TRIAL REGISTRATION: ClinicalTrials.gov number, NCT03185793.

Dysfunction of Cullin 3 RING E3 ubiquitin ligase causes vasoconstriction and increased sodium reabsorption in diabetes.

Impaired endothelium-mediated vasodilation and/or increased sensitivity to vasoconstrictors lead to vascular smooth muscle cell (VSMC) dysfunction in individuals with diabetes. Diabetic nephropathy is associated with a considerably higher risk of cardiovascular disease and death than their nondiabetic counterparts. We studied the activity of Cullin 3 RING ubiquitin ligase (CRL3) and its substrates in mice using an intraperitoneal injection of streptozotocin (STZ) and db/db mice. The levels of CRL3 adaptors, including Kelch-like 2/3 (KLHL2/3) and Rho-related BTB domain-containing protein 1, were significantly decreased in the aortic tissues and heart of the STZ group, whereas the levels of Cullin 3 (CUL3) and its neddylated derivatives were substantially increased. Decreased KLHL3 expression and significantly increased expression of NEDD8 conjugates were observed in the kidneys of db/db mice. The neddylation inhibitor MLN4924 decreased the degradation of KLHL2/KLHL3 under high-glucose conditions with/without insulin, and transfection with KLHL2 promoted the degradation of its substrates with-no-lysine (WNK) kinases. Increased abundance of WNK3, RhoA/ROCK activity and phosphodiesterase 5 enhanced the sensibility to vasoconstrictors and impaired vasodilation. Moreover, WNK3 localized in VSMCs undergoing cell division, and high-glucose medium increased WNK3 signaling in VSMCs undergoing mitosis, which might explain the increased thickness of aortic tissues in subjects with diabetes. Increases in WNK4 abundance resulted in increased sodium reabsorption in the distal renal tubules. Thus, KLHL2/RhoBTB1/KLHL3 inactivation in the aortic tissues and kidney is a result of excessive activation of neddylation in hyperglycemia and hyperinsulinemia, which affects vascular tone and sodium reabsorption.

Genome-Wide Meta-Analysis Identifies Three Novel Susceptibility Loci and Reveals Ethnic Heterogeneity of Genetic Susceptibility for IgA Nephropathy.

BACKGROUND: Eighteen known susceptibility loci for IgAN account for only a small proportion of IgAN risk. METHODS: Genome-wide meta-analysis was performed in 2628 patients and 11,563 controls of Chinese ancestry, and a replication analysis was conducted in 6879 patients and 9019 controls of Chinese descent and 1039 patients and 1289 controls of European ancestry. The data were used to assess the association of susceptibility loci with clinical phenotypes for IgAN, and to investigate genetic heterogeneity of IgAN susceptibility between the two populations. Imputation-based analysis of the MHC/HLA region extended the scrutiny. RESULTS: Identification of three novel loci (rs6427389 on 1q23.1 [P=8.18×10-9, OR=1.132], rs6942325 on 6p25.3 [P=1.62×10-11, OR=1.165], and rs2240335 on 1p36.13 [P=5.10×10-9, OR=1.114]), implicates FCRL3, DUSP22.IRF4, and PADI4 as susceptibility genes for IgAN. Rs2240335 is associated with the expression level of PADI4, and rs6427389 is in high linkage disequilibrium with rs11264799, which showed a strong expression quantitative trail loci effect on FCRL3. Of the 24 confirmed risk SNPs, six showed significant heterogeneity of genetic effects and DEFA showed clear evidence of allelic heterogeneity between the populations. Imputation-based analysis of the MHC region revealed significant associations at three HLA polymorphisms (HLA allele DPB1*02, AA_DRB1_140_32657458_T, and AA_DQA1_34_32717152) and two SNPs (rs9275464 and rs2295119). CONCLUSIONS: A meta-analysis of GWAS data revealed three novel genetic risk loci for IgAN, and three HLA polymorphisms and two SNPs within the MHC region, and demonstrated the genetic heterogeneity of seven loci out of 24 confirmed risk SNPs.  These variants may explain susceptibility differences between Chinese and European populations.

Leflunomide plus low-dose prednisone in patients with progressive IgA nephropathy: a multicenter, prospective, randomized, open-labeled, and controlled trial.

BACKGROUND: Immunoglobulin A nephropathy (IgAN) is the most common cause of glomerulonephritis worldwide, and the optimal approach to its treatment remains a significant challenge. METHODS: We did a prospective, randomized, open-labeled, multicenter, controlled trial, comprised of 3-month run-in, 12-month treatment, and 12-month follow-up phases. After 3-month run-in phase, patients with biopsy-confirmed IgAN at risk of progression were randomly allocated to LEF plus low-dose prednisone (LEF + prednisone group) or conventionally accepted-dose prednisone [prednisone(alone) group] Our primary outcome was 24-h urine protein excretion (UPE) and secondary outcomes were serum albumin (sALB), serum creatinine (Scr), and eGFR. Safety was evaluated in all patients who received the trial medications. RESULTS: One hundred and eight patients [59 in LEF + prednisone group, 49 in prednisone (alone) group]were enrolled and finished their treatment and follow-up periods. There is no significant difference in the baseline level between the two groups. Compared with baseline, both groups showed a significant decrease in 24-h UPE (p < 0.01) and increase in sALB (p < 0.01), with stable Scr and eGFR throughout the 12-month treatment period. What's more, these effects were sustained through the 12-month follow-up period. However, there was no difference in 24-h UPE, sALB, Scr, and eGFR between the two groups (p > 0.05). At 12 months, a difference in overall response rate, relapsing rate, and incidence of adverse events between the two groups was not significant. CONCLUSIONS: The efficacy and safety of LEF plus low-dose prednisone and conventionally accepted-dose prednisone in the treatment of progressive IgAN are comparable.

First identification of PODXL nonsense mutations in autosomal dominant focal segmental glomerulosclerosis.

Recently, a novel heterozygous missense mutation c.T1421G (p. L474R) in the PODXL gene encoding podocalyxin was identified in an autosomal dominant focal segmental glomerulosclerosis (AD-FSGS) pedigree. However, this PODXL mutation appeared not to impair podocalyxin function, and it is necessary to identify new PODXL mutations and determine their causative role for FSGS. In the present study, we report the identification of a heterozygous nonsense PODXL mutation (c.C976T; p. Arg326X) in a Chinese pedigree featured by proteinuria and renal insufficiency with AD inheritance by whole exome sequencing (WES). Total mRNA and PODXL protein abundance were decreased in available peripheral blood cell samples of two affected patients undergoing hemodialysis, compared with those in healthy controls and hemodialysis controls without PODXL mutation. We identified another novel PODXL heterozygous nonsense mutation (c.C1133G; p.Ser378X) in a British-Indian pedigree of AD-FSGS by WES. In vitro study showed that, human embryonic kidney 293T cells transfected with the pEGFP-PODXL-Arg326X or pEGFP-PODXL-Ser378X plasmid expressed significantly lower mRNA and PODXL protein compared with cells transfected with the wild-type plasmid. Blocking nonsense-mediated mRNA decay (NMD) significantly restored the amount of mutant mRNA and PODXL proteins, which indicated that the pathogenic effect of PODXL nonsense mutations is likely due to NMD, resulting in podocalyxin deficiency. Functional consequences caused by the PODXL nonsense mutations were inferred by siRNA knockdown in cultured podocytes and podocalyxin down-regulation by siRNA resulted in decreased RhoA and ezrin activities, cell migration and stress fiber formation. Our results provided new data implicating heterozygous PODXL nonsense mutations in the development of FSGS.

Outcomes and practice patterns with hemodiafiltration in Shanghai: a longitudinal cohort study.

BACKGROUND: Globally, there is increased clinical interest and uptake of hemodiafiltration (HDF) for increased removal of uremic toxins. To date, there has been no epidemiological analysis of HDF in China. We present HDF practice patterns and associated mortality risk in Shanghai. METHODS: This is an observational, prospectively collected, retrospective analysis of 9351 Chinese patients initiating hemodialysis in Shanghai from 2007 to 2014. The primary exposure was hemodialysis sub-modality at inception, classified into hemodiafiltration (HDF) and hemodialysis (HD), with adjustment for concommitant hemoperfusion. The primary outcome was patient mortality. We used Cox proportional hazards regression and Fine and Gray's proportional subhazards regression, with multiple imputation of missing co-variates by the chained equation method, adjusting for demographic and clinical variables. RESULTS: Overall, patients in the cohort were younger, with a more males, and with a lower body mass index when compared to corresponding non-Asian cohorts. Mortality rate was low although it doubled over the period of observation. HDF utilization increased from 7% of patients in 2007 to 42% of patients in 2014. The majority of patients received HDF once a week. The adjusted hazard ratio of death (95% confidence intervals) for HDF versus HD was 0.85 (0.71-1.03), and corresponding sub-hazard ratio 0.86 (0.71-1.03). There was strong effect modification by age. In those aged 40-60 years, the hazard ratio (95% confidence intervals) was 0.65 (0.45-0.94), and sub-hazard ratio also 0.65 (0.45-0.95). CONCLUSIONS: Our study has certain limitations resulting from the limited number of co-variates available for modelling, missing data for some co-variates, and the lack of verification of data against source documentation. Notwithstanding, there is evidence of clinical benefit from HDF in China, and potential to improve patient outcomes through the greater removal of middle and larger uremic solutes.

A Telemedicine-Based Registration System for the Management of Renal Anemia in Patients on Maintenance Hemodialysis: Multicenter Study.

BACKGROUND: Renal anemia is one of the most important complications in patients on maintenance hemodialysis (MHD). Telehealth-based dialysis registration systems have the advantage of real-time monitoring and have gradually been applied to the management of chronic diseases. OBJECTIVE: The objective of our study was to evaluate the impact of a telehealth-based dialysis registration system on patients on MHD in terms of renal anemia control. METHODS: The Red China project aimed to develop a dialysis registration system based on the WeChat mobile platform. Demographic and baseline laboratory parameters such as age, gender, primary disease, dialysis age, and baseline creatinine levels were recorded using this system. In addition, the hemoglobin and hematocrit levels were recorded monthly. The platform then generated a hemoglobin and hematocrit statistics report for each hemodialysis center monthly, including the detection rate, target rate, and distribution of hemoglobin and released it to physicians via the WeChat mobile phone app. The physicians were then able to treat the individual's anemia appropriately by changing the doses of erythropoiesis-stimulating agents or iron use on the basis of this report. We analyzed the demographic and baseline laboratory parameters, detection rate, target rate, and average level and distribution of hemoglobin 28 months after the launch of the project. RESULTS: A total of 8392 patients on MHD from 28 hemodialysis centers in Shanghai were enrolled from June 2015 to October 2017. The detection rate of hemoglobin increased from 54.18% to 73.61% (P<.001), the target rate of hemoglobin increased from 47.55% to 56.07% (P<.001), and the mean level of hemoglobin increased from 10.83 (SD 1. 60) g/dL to 11.07 (SD 1.60) g/dL (P<.001). In addition, the proportion of patients with hemoglobin levels ≥11 g/dL but <13 g/dL increased from 40.40% to 47.48%. CONCLUSIONS: This telehealth-based dialysis registration system can provide timely reporting of the anemia status in patients on MHD, which may improve the awareness of anemia and the attention to and compliance with anemia monitoring.

Epigenetic regulation of RCAN1 expression in kidney disease and its role in podocyte injury.

Mounting evidence suggests that epigenetic modification is important in kidney disease pathogenesis. To determine whether epigenetic regulation is involved in HIV-induced kidney injury, we performed genome-wide methylation profiling and transcriptomic profiling of human primary podocytes infected with HIV-1. Comparison of DNA methylation and RNA sequencing profiles identified several genes that were hypomethylated with corresponding upregulated RNA expression in HIV-infected podocytes. Notably, we found only one hypermethylated gene with corresponding downregulated RNA expression, namely regulator of calcineurin 1 (RCAN1). Further, we found that RCAN1 RNA expression was suppressed in glomeruli in human diabetic nephropathy, IgA nephropathy, and lupus nephritis, and in mouse models of HIV-associated nephropathy and diabetic nephropathy. We confirmed that HIV infection or high glucose conditions suppressed RCAN1 expression in cultured podocytes. This suppression was alleviated upon pretreatment with DNA methyltransferase inhibitor 5-Aza-2'-deoxycytidine, suggesting that RCAN1 expression is epigenetically suppressed in the context of HIV infection and diabetic conditions. Mechanistically, increased expression of RCAN1 decreased HIV- or high glucose-induced nuclear factor of activated T cells (NFAT) transcriptional activity. Increased RCAN1 expression also stabilized actin cytoskeleton organization, consistent with the inhibition of the calcineurin pathway. In vivo, knockout of RCAN1 aggravated albuminuria and podocyte injury in mice with Adriamycin-induced nephropathy. Our findings suggest that epigenetic suppression of RCAN1 aggravates podocyte injury in the setting of HIV infection and diabetic nephropathy.

Clinical and Histological Features of Phospholipase A2 Receptor-Associated and Thrombospondin Type-I Domain-containing 7A-Associated Idiopathic Membranous Nephropathy: A Single Center Retrospective Study from China.

BACKGROUND M-type phospholipase A2 receptor (PLA2R) was identified as the major target antigen in idiopathic membranous nephropathy (IMN). Another target antigen, namely thrombospondin type-1 domain-containing 7A (THSD7A), was recently detected in approximately 10% of non-PLA2R-associated IMN. In this single center retrospective study, clinical and histological features of PLA2R-associated and THSD7A-associated IMN patients were evaluated. MATERIAL AND METHODS A total of 192 IMN patients, who were receiving no glucocorticoids or immunosuppressant before renal biopsy, were enrolled in this study and followed for a median duration of 25.5 months. IMN with enhanced glomerular PLA2R and THSD7A staining by immunohistochemistry (IHC) were designated as PLA2R-associated IMN and THSD7A-associated IMN respectively. Serum anti-PLA2R and anti-THSD7A antibodies levels were assessed by enzyme linked immunosorbent assay and indirect immunofluorescence testing in PLA2R-associated and THSD7A-associated IMN. RESULTS Of 192 IMN patients, 164 patients (85.4%) had PLA2R-associated IMN and 3 patients (1.6%) had THSD7A-associated IMN. Compared with non-PLA2R-associated IMN patients, the 24-hour urinary protein levels were significantly higher (P=0.008), whereas, the proteinuria remission rates were significantly lower (P=0.03) in PLA2R-associated IMN patients. No pathological differences were found between PLA2R-associated IMN and non-PLA2R-associated IMN. Among 3 THSD7A-associated IMN patients, 1 patient had elevated serum anti-THSD7A antibody levels, which was below detectable levels after achieving partial proteinuria remission with combined glucocorticoid and cyclosporine treatment. CONCLUSIONS Compared with non-PLA2R-associated IMN patients in our cohort, PLA2R-associated IMN patients presented with more severe proteinuria and lower remission rates after treatment, with no distinct histological differences. Glomerular expression of PLA2R could be a useful marker to indicate the severity, treatment response, and prognosis of IMN.

Inhibition of Reticulon-1A-Mediated Endoplasmic Reticulum Stress in Early AKI Attenuates Renal Fibrosis Development.

Several animal studies have shown an important role for endoplasmic reticulum (ER) stress in AKI, whereas human studies are lacking. We recently reported that Reticulon-1A (RTN1A) is a key mediator of ER stress and kidney cell injury. Here, we investigated whether modulation of RTN1A expression during AKI contributes to the progression to CKD. In a retrospective study of 51 patients with AKI, increased expression of RTN1A and other ER stress markers were associated with the severity of kidney injury and with progression to CKD. In an inducible tubular cell-specific RTN1A-knockdown mouse model subjected to folic acid nephropathy (FAN) or aristolochic acid nephropathy, reduction of RTN1A expression during the initial stage of AKI attenuated ER stress and kidney cell injury in early stages and renal fibrosis development in later stages. Treatment of wild-type mice with tauroursodeoxycholic acid, an inhibitor of ER stress, after the induction of kidney injury with FA facilitated renoprotection similar to that observed in RTN1A-knockdown mice. Conversely, in transgenic mice with inducible tubular cell-specific overexpression of RTN1A subjected to FAN, induction of RTN1A overexpression aggravated ER stress and renal injury at the early stage and renal fibrosis at the late stage of FAN. Together, our human and mouse data suggest that the RTN1A-mediated ER stress response may be an important determinant in the severity of AKI and maladaptive repair that may promote progression to CKD.

Resveratrol attenuates skeletal muscle atrophy induced by chronic kidney disease via MuRF1 signaling pathway.

Skeletal muscle atrophy is an important clinical characteristic of chronic kidney disease (CKD); however, at present, the therapeutic approaches to muscle atrophy induced by CKD are still at an early stage of development. Resveratrol is used to attenuate muscle atrophy in other experimental models, but the effects on a CKD model are largely unknown. Here, we showed that resveratrol prevented an increase in MuRF1 expression and attenuated muscle atrophy in vivo model of CKD. We also found that phosphorylation of NF-κB was inhibited at the same time. Dexamethasone-induced MuRF1 upregulation was significantly attenuated in C2C12 myotubes by resveratrol in vitro, but this effect on C2C12 myotubes was abrogated by a knockdown of NF-κB, suggesting that the beneficial effect of resveratrol was NF-κB dependent. Our findings provide novel information about the ability of resveratrol to prevent or treat muscle atrophy induced by CKD.

Prognostic Value of the Delivery Dialysis Dose on Twice-Weekly Hemodialysis Patients.

BACKGROUND: Few studies have evaluated the prognostic value of dialysis dose in twice-weekly hemodialysis (HD). A single-pool Kt/V (spKt/V) over 1.70 may benefit patients receiving twice-weekly maintenance HD. METHODS: This is a multicenter randomized controlled trial performed on 163 patients from 17 dialysis centers in Shanghai who were allocated to high- (n = 98) and standard-dose groups (n = 65) and followed through 96 weeks of study period. Therapeutic approaches were given to increase spKt/V to over 1.70 in the high-dose group. Data were collected every 12-24 weeks. The primary outcomes were all-cause mortality and major adverse cardio-cerebrovascular events (MACEs) occurrence, and secondary outcomes included residual kidney function (RKF) and health-related quality of life (HR-QOL). RESULTS: The spKt/V in high-dose and standard-dose groups were 1.80 ± 0.23 and 1.55 ± 0.19, respectively, after an 8-week intervention (p < 0.001). At the end of the study, SF-36 physical function and total score in high-dose group were 82 (69-90) and 74 (47-84), respectively, both of which were higher than those in the standard-dose group. Decline in urine volume was observed in both groups with no significant difference (p = 0.431). No difference was found in overall survival between the 2 groups (p = 0.580). The 1-year MACE-free survival for high-dose group was 84.49%, better than 76.72% for standard-dose group (p = 0.029). CONCLUSIONS: Higher spKt/V is also associated with MACE-free survival and better HR-QOL, especially in physical function aspect for twice-weekly dialysis patients. Increasing spKt/V over 1.70 in twice-weekly HD population does not cause loss of RKF.