Disturbed carnitine metabolism is independently correlated with sarcopenia and prognosis in patients on hemodialysis.

BACKGROUND & AIMS: Sarcopenia is frequent in hemodialysis patients and associated with an increased likelihood of adverse outcomes. Early identification of the risk of sarcopenia and effective intervention are of great importance for dialysis patients. However, little research has been carried out on potential biomarkers of sarcopenia in hemodialysis patients. The aim of this study was to investigate whether serum carnitine or acylcarnitine levels are biomarkers of sarcopenia in hemodialysis patients, and whether these are prognostic factors for occurrence of complications. METHODS: This prospective clinical pilot study enrolled patients (n = 259) who were treated in the Blood Purification Center from May 2021 to July 2022, all participants were followed-up for 1- year. Serum carnintine and acylcarnitine (AC) were measured using our previously reported targeted liquid chromatography tandem mass spectrometry (LC-MS/MS) method. The correlations between carnitine or acylcarnitine levels with sarcopenia and prognosis in patients were analysed. RESULTS: The C0 (Free carnitine, FC) and total carnitine (TC) levels were significantly lower in the sarcopenia group than in the nonsarcopenia group [nonsarcopenia vs. sarcopenia: 20.97 (16.96, 25.83) vs. 17.77 (14.30, 22.78); p = 0.002] and [nonsarcopenia vs. sarcopenia: 30.12 (24.76, 36.62) vs. 26.03 (21.30, 32.01); p = 0.003]. Besides, significant difference between the groups were noted in low free carnitine (C0 < 20 µmol/L) patients (nonsarcopenia vs. sarcopenia: 72 (42.4%) vs. 56 (62.9%); p = 0.002) and high C2/C0 ratio (>0.4) patients (nonsarcopenia vs. sarcopenia: 36 (21.2%) vs. 30 (33.7%); p = 0.028). By multivariable analysis, the disturbed CM defined as C0 deficient and/or C2/C0 carnitine ratio abnormal rise was independently and significantly correlated with the prevalence of sarcopenia after adjusting for some confounding factors, such as age, gender and dialysis duration (P values for trend <0.05). Hemodialysis patients with sarcopenia [OR: 3.214 (1.307,7.904)] and disturbed CM [OR: 3.217 (1.112,9.305)] both had a 3-fold increased risk of falling and fracture after one year follow up. In addition, age and sarcopenia [OR: 2.883 (1.321, 6.289)] were independently and positively associated with incidence of Cardio- and cerebro-vascular events. CONCLUSION: Disturbed carnitine metabolism is independently correlated with sarcopenia and prognosis in patients with hemodialysis. Serum carnitine level and C0/C2 ratio has the potential to be a simple, objective, and quick test for sarcopenia assessment whether such an intervention should be carried out for dialysis patients.

Dipeptidase 1 promotes ferroptosis in renal tubular epithelial cells in diabetic nephropathy via inhibition of the GSH/GPX4 axis.

Renal tubular injury is an important pathological change associated with diabetic nephropathy (DN), in which ferroptosis of renal tubular epithelial cells is critical to its pathogenesis. Inhibition of the glutathione/glutathione peroxidase 4 (GSH/GPX4) axis is the most important mechanism in DN tubular epithelial cell ferroptosis, but the underlying reason for this is unclear. Our biogenic analysis showed that a zinc-dependent metalloproteinase, dipeptidase 1 (DPEP1), is associated with DN ferroptosis. Here, we investigated the role and mechanism of DPEP1 in DN tubular epithelial cell ferroptosis. DPEP1 upregulation was observed in the renal tubular epithelial cells of DN patients and model mice, as well as in HK-2 cells stimulated with high glucose. Furthermore, the level of DPEP1 upregulation was associated with the degree of tubular injury in DN patients and HK-2 cell ferroptosis. Mechanistically, knocking down DPEP1 expression could alleviate the inhibition of GSH/GPX4 axis and reduce HK-2 cell ferroptosis levels in a high glucose environment. HK-2 cells with stable DPEP1 overexpression also showed GSH/GPX4 axis inhibition and ferroptosis, but blocking the GSH/GPX4 axis could mitigate these effects. Additionally, treatment with cilastatin, a DPEP1 inhibitor, could ameliorate GSH/GPX4 axis inhibition and relieve ferroptosis and DN progression in DN mice. These results revealed that DPEP1 can promote ferroptosis in DN renal tubular epithelial cells via inhibition of the GSH/GPX4 axis.

Secreted frizzled-related protein 5 protects against renal fibrosis by inhibiting Wnt/ß-catenin pathway.

Renal fibrosis (RF) is an important pathogenesis for renal function deterioration in chronic kidney disease. Secreted frizzled-related protein 5 (SFRP5) is an anti-fibrotic adipokine but its direct role on RF remains unknown. It was aimed to study the protective effect of SFRP5 against RF and interference with Wnt/ß-catenin signaling pathway for the first time. First, the therapeutic efficacy of SFRP5 was evaluated by adenovirus overexpression in rats with unilateral ureteral obstruction (UUO) in vivo. Thirty-six rats were randomly divided into the sham, UUO, and SFRP5 (UUO + Ad-SFRP5) groups. Half rats in each group were selected at random for euthanasia at 7 days and the others until 14 days. Then, the transforming growth factor (TGF)-ß1-induced epithelial-mesenchymal transition (EMT) was established in HK-2 cells in vitro. The cells were divided into four groups: the control group, the TGF-ß1 group, the TGF-ß1 + SFRP5 group, and the TGF-ß1 + SFRP5 + anti-SFRP5 group. The makers of EMT and Wnt/ß-catenin pathway proteins were investigated. In the UUO model, expression of SFRP5 showed compensatory upregulation, and adenoviral-mediated SFRP5 over-expression remarkably attenuated RF, as demonstrated by maintenance of E-cadherin and suppression of α-smooth muscle actin (SMA). In vitro, SFRP5 was shown to inhibit TGF-ß1-mediated positive regulation of α-SMA, fibronectin, collagen I but negative regulation of E-cadherin. Furthermore, SFRP5 abrogated activation of Wnt/ß-catenin, which was the essential pathway in EMT and RF pathogenesis. The changes after a neutralizing antibody to SFRP5 confirmed the specificity of SFRP5 for inhibition. These findings suggest that SFRP5 can directly ameliorate EMT and protect against RF by inhibiting Wnt/ß-catenin pathway.

Pericyte activation accompanied by peritubular capillaries dysfunction and pericyte-to-myofibroblast transition is associated with renal fibrosis in diabetic nephropathy.

Background: Tubulointerstitial renal fibrosis is an essential feature of diabetic nephropathy (DN). Pericytes play a critical role in microvascular diseases and renal fibrogenesis. However, the role of pericytes in DN remains unclear. Herein, we aimed to explore the properties and possible mechanisms of pericytes in renal fibrosis in DN. Methods: We used multiplex immunofluorescence staining to evaluate the location and expression of activated pericytes and to assess capillary dilation and interstitial fibrosis in the kidneys of db/db mice. Pericytes were co-stained for alpha-smooth muscle actin (α-SMA) to determine which ones differentiate into myofibroblasts in db/db mice. Expression of CD34 and platelet-derived growth factor receptor beta (PDGFR-ß) was assessed in kidney tissue from patients with DN by immunohistochemical staining. Results: We found that cell staining for nerve/glial antigen 2 (NG2)+ and PDGFR-ß+ was greater in the kidneys of db/db mice than in those of db/m mice. There was impaired pericyte coverage of blood vessels and capillary dilation in the renal interstitium. These changes were accompanied by increased collagen I staining and an increase in the number of pericytes with profibrotic phenotypes, as identified by increased NG2+/PDGFR-ß+/α-SMA+ and decreased NG2+/PDGFR-ß+/α-SMA- staining. In DN patients, expression of PDGFR-ß was stronger and there was loss of CD34 compared with the findings in control patients with minor glomerular lesions. Conclusion: In this study, we demonstrated that pericyte activation accompanied by peritubular capillary dysfunction and pericytemyofibroblast transition is associated with renal fibrosis in DN.

Renomegaly and acute kidney injury as primary manifestations of non-Hodgkin's lymphoma: a report of three cases.

BACKGROUND: In adults with non-Hodgkin's lymphoma, renal enlargement and acute kidney injury occur infrequently at first presentation, especially in T lymphocytic lymphomas. CASE PRESENTATION: We report three cases of non-Hodgkin's lymphoma with acute renal injury and bilateral renal enlargement. At diagnosis, one patient presented with an adrenal mass, one patient's lymph node biopsy was consistent with a renal biopsy, and one patient had primary renal lymphoma with no extrarenal disease. Assessment of renal pathology in Case 2 and Case 3 showed interstitial lymphocyte infiltration; the pathological types were non-Hodgkin's diffuse large B lymphoma originating from activated B cells outside germinal centers and non-Hodgkin's T-lymphoblastic lymphoma/leukemia, respectively. Case 1 did not receive anti-lymphoma therapy and died from infection and multiple organ failure within 1 month of hospitalization. Case 2 received eight courses of R-CHOP; her lymphoma recurred 2 years after diagnosis and she died from severe pulmonary infection 3 years after diagnosis. Case 3 received hyper-CVAD regularly and achieved stable renal function; this patient remains under follow-up. CONCLUSIONS: Renal lymphoma may have diverse manifestations, especially primary renal lymphoma without extrarenal involvement. Nephrologists should pay careful attention to these manifestations to ensure accurate diagnosis.

Frailty and Adverse Outcomes After SARS-CoV-2 Infection in Elderly Patients on Maintenance Hemodialysis: A Cohort Study.

Purpose: Frailty is an important geriatric syndrome associated with aging and adverse events, especially in patients with severe infection. To help guide prognosis for elderly patients undergoing maintenance hemodialysis (MHD) who experience acute infection, this study investigated whether baseline (pre-infection) frailty may be associated with adverse outcomes in elderly patients undergoing MHD who suffer SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) infection. Patients and Methods: Patients (aged ≥60 y) receiving MHD had been assessed for overall frailty and the 5 frailty components based on the Fried Frailty Phenotype scale within 3 months prior to SARS-CoV-2 infection. Results: There were 59 and 98 patients in the frail and non-frail groups, respectively. Three months after SARS-CoV-2 infection, 21 (13.4%) and 45 (28.7%) patients had died or were in hospital. The multivariate COX proportional risk model suggested that the all-cause mortality rate in patients judged overall frail or with low activity was significantly higher compared with that of the non-frail (P = 0.049; 0.003). The multivariate logistic regression analysis showed that hospitalization 3 months after SARS-CoV-2 infection was associated with both overall frailty and low activity (OR 2.276, 95% CI: 1.034-5.010, P = 0.041; OR 2.809, 95% CI: 1.311-6.020, P = 0.008, respectively). Conclusion: Overall frailty and specifically low activity were significantly associated with all-cause mortality and hospitalization in this elderly MHD population after SARS-CoV-2 infection. Early assessment of frailty and effective interventions are recommended to improve the prognosis of patients receiving MHD who are at higher risk of acute infection.

Nirmatrelvir/ritonavir use in patients with COVID-19 on hemodialysis: a case series.

Patients undergoing hemodialysis (HD) are particularly vulnerable to coronavirus disease 2019 (COVID-19) and are at increased risk of developing severe infection. However, given the exclusion of such patients from clinical trials, there are limited data regarding the effectiveness of the antiviral drug nirmatrelvir/ritonavir (N/R) in patients on HD. We prescribed N/R to 4 patients on HD with COVID-19 after obtaining informed consent. Their clinical symptoms were improved at approximately 3 days after N/R administration. The viral load was reduced after approximately 10 days. The main adverse effects were nausea and vomiting. Rational dosage adjustment obtained good tolerance but did not influence the efficacy. These results suggest that N/R may be a promising agent for patients on HD with COVID-19.

Epidemiological analysis of death among patients on maintenance hemodialysis: results from the beijing blood purification quality Control and Improvement Center.

BACKGROUND: China has the largest number of patients on maintenance hemodialysis (MHD) worldwide. Despite continuous improvements in hemodialysis techniques, patients on MHD have a higher mortality rate than the general population. Understanding the characteristics of death in this population can better promote clinical practice, thereby improving patients' survival. METHODS: We collected demographic and clinical data for patients on MHD registered in the Beijing Blood Purification Quality Control and Improvement Center database from 2014 to 2020. The annual mortality rate was calculatedand the primary cause of end-stage renal disease (ESRD), dialysis vintage, and cause of death among deceased patients were analyzed. RESULTS: (1) 24,363 patients on MHD were included, of which 6,065 patients died from 2014 to 2020. The annual mortality rate fluctuated between 7.4% and 8.0%. The median age of death was 70.0 (60.8-79.0) years and the male to female ratio was 1.27:1 (2). The top three primary causes of ESRD in deceased patients were chronic glomerulonephritis (CGN), diabetic nephropathy (DN), and hypertensive nephropathy (HN). Comparison of the annual mortality rate showed DN > HN > CGN (3). The median dialysis vintage of deceased patients was 3.7 (1.8-6.9) years, which slowly increased annually. Patients with diabetes had a shorter dialysis vintage than patients without diabetes (3.4 vs. 4.1 years, Z = 8.3, P < 0.001) (4). The major causes of death were cardiovascular disease (20.2%), sudden death (18.1%), infection (17.9%), and cerebrovascular disease (12.6%). Proportions of death from cardiovascular disease, infection, and sudden death were higher in patients with diabetes (22.2%, 20.2%, and 20.0%) than patients without diabetes (18.4%, 15.8%, and 16.3%). Sudden death was the leading cause of death in young (18-44 years; 27.0%) and middle aged (45-64 years; 20.8%) patients, whereas infection was the leading cause of death in patients aged ≥ 75 years (24.5%). CONCLUSION: The annual mortality rate of patients on MHD in Beijing was relatively stable from 2014 to 2020. Sudden death was more likely to occur in young and middle-aged patients, and more patients aged ≥ 75 years died from infections.

Multitarget therapy with a corticosteroid, cyclosporine and mycophenolate mofetil for idiopathic membranous nephropathy: a prospective randomized controlled trial.

BACKGROUND: The effectiveness of multitarget combination therapy with a corticosteroid, cyclosporine and mycophenolate mofetil for idiopathic membranous nephropathy (IMN) is unclear. In the present study, we aimed to compare the efficacy and safety of multitarget therapy with a cyclical corticosteroid-cyclophosphamide regimen in patients with IMN. METHODS: This was a single-centre, prospective, randomized, controlled trial. We randomly assigned patients with IMN to receive multitarget therapy (a combination of prednisone, cyclosporine and mycophenolate mofetil) or 6-month cyclical treatment with a corticosteroid and cyclophosphamide. The study patients were followed up for 12 months. The primary outcome was a composite of complete or partial remissions at 12 months. Adverse events were also assessed. RESULTS: The study cohort comprised 78 patients, 39 of whom received multitarget therapy and the other 39 cyclical alternating treatment with a corticosteroid and cyclophosphamide. At 12 months, 31 of 39 patients (79%) in the multitarget therapy group and 34 of 39 (87%) in the corticosteroid-cyclophosphamide group had achieved complete or partial remissions (relative risk 0.93; 95% confidence interval 0.72-1.21; P = .85; log-rank test). The prevalence of adverse events was significantly lower in the multitarget therapy group than in the corticosteroid-cyclophosphamide group [46% (18 of 39) vs 74% (29 of 39); P < .05]. CONCLUSIONS: Multitarget therapy for IMN patients is noninferior to cyclical alternating treatment with corticosteroid and cyclophosphamide in inducing proteinuria remission and has a better safety profile than the corticosteroid-cyclophosphamide combination.

Effect of dialytic phosphate reduction rate on mortality in maintenance hemodialysis patients: a matched case-control study.

BACKGROUND: Phosphates, similar to urea, are small molecular substances that can be cleared during dialysis. Dialytic phosphate reduction rate (PRR) may, to some extent, be related to the relative amount of phosphates cleared during dialysis. However, few studies have evaluated the associations between PRR and mortality in maintenance hemodialysis (MHD) patients. In this study, we investigated the association between PRR and clinical outcomes in MHD patients. METHODS: This was a retrospective, matched case-control study. Data were collected from the Beijing Hemodialysis Quality Control and Improvement Center. Patients were divided into four groups according to PRR quartile. Age, sex, and diabetes were matched between the groups. The primary outcome was all-cause death, and the secondary outcome was cardiocerebrovascular death. RESULTS: The study cohort comprised 4063 patients who were divided into four groups according to the PRR quartile: group PRR1 (< 48.35%), group PRR2 (48.35% - 54.14%), group PRR3 (54.14% - 59.14%), and group PRR4 (≥ 59.14%). We enrolled 2172 patients (543 in each study group) by case-control matching. The all-cause death rates were as follows: group PRR1: 22.5% (122/543), group PRR2: 20.1% (109/543), group PRR3: 19.3% (105/543), and group PRR4: 19.3% (105/543). No significant differences in all-cause and cardiocerebrovascular death rates according to the Kaplan-Meier survival curves were found between the groups (log-rank test, P > 0.05). Multivariable Cox regression analysis revealed no significant differences in all-cause and cardiocerebrovascular death rates between the four groups (P = 0.461; adjusted hazard ratio, 0.99; 95% confidence interval, 0.97 - 1.02 versus P = 0.068; adjusted hazard ratio, 0.99; 95% confidence interval, 0.97 - 1.00, respectively). CONCLUSIONS: Dialytic PRR was not significantly associated with all-cause death and cardiocerebrovascular death in MHD patients.

Renalase Prevents Renal Fibrosis by Inhibiting Endoplasmic Reticulum Stress and Down-Regulating GSK-3ß/Snail Signaling.

Background: Treating renal fibrosis is crucial to delaying chronic kidney disease. The glycogen synthase kinase-3ß (GSK-3ß)/Snail pathway regulates renal fibrosis and Renalase can ameliorate renal interstitial fibrosis. However, it is not clear whether GSK-3ß/Snail signaling affects Renalase action. Here, we explored the role and mechanism of GSK-3ß/Snail in the anti-fibrosis action of Renalase. Materials and methods: We used mice with complete unilateral ureteral obstruction (UUO) and human proximal renal tubular epithelial (HK-2) cells with transforming growth factor-ß1 (TGF-ß1)-induced fibrosis to explore the role and regulatory mechanism of the GSK-3ß/Snail pathway in the amelioration of renal fibrosis by Renalase. Results: In UUO mice and TGF-ß1-induced fibrotic HK-2 cells, the expression of p-GSK-3ß-Tyr216/p-GSK-3ß-Ser9, GSK-3ß and Snail was significantly increased, and endoplasmic reticulum (ER) stress was activated. After Renalase supplementation, fibrosis was alleviated, ER stress was inhibited and p-GSK-3ß-Tyr216/p-GSK-3ß-Ser9, GSK-3ß and Snail were significantly down-regulated. The amelioration of renal fibrosis by Renalase and its inhibitory effect on GSK-3ß/Snail were reversed by an ER stress agonist. Furthermore, when an adeno-associated virus or plasmid was used to overexpress GSK-3ß, the effect of Renalase on delaying renal fibrosis was counteracted, although ER stress markers did not change. Conclusion: Renalase prevents renal fibrosis by down-regulating GSK-3ß/Snail signaling through inhibition of ER stress. Exogenous Renalase may be an effective method of slowing or stopping chronic kidney disease progression.

Bioinformatics analysis of potential key ferroptosis-related genes involved in tubulointerstitial injury in patients with diabetic nephropathy.

Diabetic nephropathy (DN) is the primary complication of diabetes mellitus. Ferroptosis is a form of cell death that plays an important role in DN tubulointerstitial injury, but the specific molecular mechanism remains unclear. Here, we downloaded the DN tubulointerstitial datasets GSE104954 and GSE30529 from the Gene Expression Omnibus database. We examined the differentially expressed genes (DEGs) between DN patients and healthy controls, and 36 ferroptosis-related DEGs were selected. Pathway-enrichment analyses showed that many of these genes are involved in metabolic pathways, phosphoinositide 3-kinase/Akt signaling, and hypoxia-inducible factor-1 signaling. Ten of the 36 ferroptosis-related DEGs (CD44, PTEN, CDKN1A, DPP4, DUSP1, CYBB, DDIT3, ALOX5, VEGFA, and NCF2) were identified as key genes. Expression patterns for six of these (CD44, PTEN, DDIT3, ALOX5, VEGFA, and NCF2) were validated in the GSE30529 dataset. Nephroseq data indicated that the mRNA expression levels of CD44, PTEN, ALOX5, and NCF2 were negatively correlated with the glomerular filtration rate (GFR), while VEGFA and DDIT3 mRNA expression levels were positively correlated with GFR. Immune infiltration analysis demonstrated altered immunity in DN patients. Real-time quantitative PCR (qPCR) analysis showed that ALOX5, PTEN, and NCF2 mRNA levels were significantly upregulated in high-glucose-treated human proximal tubular (HK-2) cells, while DDIT3 and VEGFA mRNA levels were significantly downregulated. Immunohistochemistry analysis of human renal biopsies showed positive staining for ALOX5 and NCF2 protein in DN samples but not the controls. These key genes may be involved in the molecular mechanisms underlying ferroptosis in patients with DN, potentially through specific metabolic pathways and immune/inflammatory mechanisms.

Lymphocyte-to-C reactive protein ratio as novel inflammatory marker for predicting outcomes in hemodialysis patients: A multicenter observational study.

Background: Patients undergoing hemodialysis experience inflammation, which is associated with a higher risk of mortality. The lymphocyte-to-C reactive protein ratio (LCR) is a novel marker of inflammation that has been shown to predict mortality in patients with malignant cancer. However, the utility of LCR has not been evaluated in patients undergoing hemodialysis. Methods: We performed a multi-center cohort study of 3,856 patients who underwent hemodialysis as part of the Beijing Hemodialysis Quality Control and Improvement Project between 1 January 2012 and December 2019. The relationship between LCR and all-cause mortality was assessed using a restricted cubic spline model and a multivariate Cox regression model. An outcome-oriented method was used to determine the most appropriate cut-off value of LCR. Subgroup analysis was also performed to evaluate the relationships of LCR with key parameters. Results: Of the 3,856 enrolled patients, 1,581 (41%) were female, and their median age was 62 (53, 73) years. Over a median follow-up period of 75.1 months, 1,129 deaths occurred. The mortality rate for the patients after 60 months was 38.1% (95% confidence interval (CI) 36%-40.1%), resulting in a rate of 93.41 events per 1,000 patient-years. LCR showed an L-shaped dose-response relationship with all-cause mortality. The optimal cut-off point for LCR as a predictor of mortality in hemodialysis patients was 1513.1. An LCR of ≥1513.1 could independently predict mortality (hazard ratio 0.75, 95% CI 0.66-0.85, P<0.001). Conclusions: Baseline LCR was found to be an independent prognostic biomarker in patients undergoing hemodialysis. Implying that it should be a useful means of improving patient prognosis and judging the timing of appropriate interventions in routine clinical practice.

Title: Bioinformatic Identification of Genes Involved in Diabetic Nephropathy Fibrosis and their Clinical Relevance.

Tubulointerstitial fibrosis is an important pathological feature of diabetic nephropathy that is associated with impaired renal function. However, the mechanism by which fibrosis occurs in diabetic nephropathy is unclear. Differentially expressed genes were identified from transcriptome profiles of renal tissue from diabetic patients and unilateral ureteral obstruction mice and intersected to obtain genes that may be involved in diabetic fibrosis. Biological function analysis and protein-protein interaction network analysis were performed. ROC curve and Pearson correlation analysis between hub genes were performed and glomerular filtration rate estimated. Finally, the RNA levels of hub genes were measured using real-time PCR. A total of 283 genes were identified as potentially involved in diabetic nephropathy fibrosis. TYROBP, CTSS, LCP2, LUM and TLR7 were identified as aberrantly expressed hub genes. Immune cell infiltration analysis demonstrated higher numbers of cytotoxic lymphocytes, B lineage cells, monocyte lineage cells, myeloid dendritic cells, neutrophils, and fibroblasts in the diabetic nephropathy group. The areas under ROC curves for TYROBP, CTSS, LCP2, LUM and TLR7 were 0.9167, 0.9583, 0.9917, 0.93333, and 0.9583, respectively (P < 0.001), and their correlation coefficients with estimated glomerular filtration rate were - 0.8332, - 0.752, - 0.7875, - 0.7567, and - 0.7136, respectively (P < 0.001). The RNA levels of TYROBP, CTSS, LUM and TLR7 were upregulated in high-glucose-treated human renal tubular epithelial cells (P < 0.005). Our study identified TYROBP, CTSS, LCP2, LUM and TLR7 as potentially involved in diabetic nephropathy fibrosis. Furthermore, TYROBP, CTSS, LUM and TLR7 may be associated with epithelial-mesenchymal transition of tubular epithelial cells.

Exosomes from high glucose-treated macrophages promote epithelial-mesenchymal transition of renal tubular epithelial cells via long non-coding RNAs.

BACKGROUND: Macrophages contribute to epithelial-mesenchymal transition (EMT) in diabetic nephropathy (DN). Exosomal long non-coding RNAs (lncRNAs) derived from macrophages play a major role in transmitting biological information, whereas related studies on DN are rare. Here we investigated the effects of exosomal lncRNAs from high glucose-treated macrophages on EMT. METHODS: High glucose-treated macrophage exosomes (HG-exos) were extracted by coprecipitation and stabilized. Then, mouse renal tubular epithelial cells were treated with HG-exos for 24 h. Expression of E-cadherin, α-smooth muscle actin (α-SMA), and fibronectin was detected by western blotting, qPCR, and immunofluorescence. High-throughput sequencing was then applied to analyze the bioinformatics of HG-exos. RESULTS: HG-exos inhibited the proliferation of tubular epithelial cells. Additionally, HG-exos markedly upregulated α-SMA and fibronectin expression and downregulated E-cadherin expression in tubular epithelial cells, indicating EMT induction. A total of 378 differentially expressed lncRNAs and 674 differentially expressed mRNAs were identified by high-throughput sequencing of HG-exos. Bioinformatics analysis and subsequent qPCR validation suggested 27 lncRNAs were enriched in the EMT-related MAPK pathway. Among them, ENSMUST00000181751.1, XR_001778608.1, and XR_880236.2 showed high homology with humans. CONCLUSION: Exosomes from macrophages induce EMT in DN and lncRNAs in exosomes enriched in the MAPK signaling pathway may be the possible mechanism.

Stanniocalcin 2 Is Upregulated by Calcium-Sensing Receptor and Protects Human Vascular Smooth Muscle Cells from High-Phosphate-Induced Apoptosis.

INTRODUCTION: Apoptosis of vascular smooth muscle cells induced by hyperphosphatemia is a critical mechanism of chronic kidney disease-related vascular disorders. The present study investigated whether extracellular calcium-sensing receptor (CaSR) regulates stanniocalcin 2 (STC2) expression in HAoSMCs and subsequently protects HAoSMCs from high-phosphate-induced apoptosis. METHODS: HAoSMCs were cultured, and STC2 expression was determined by qPCR. A calcimimetic (NPS R-568) or calcilytic (NPS-2143) was applied to HAoSMCs. STC2 mRNA and protein levels were measured by qPCR and Western blot, respectively, and confocal microscopy was employed to investigate subcellular localization. STC2 overexpression and silencing were induced to assess the effects of STC2 on high-phosphate-induced apoptosis, which was determined by caspase-3 levels and TUNEL staining. The anti-apoptotic effect of CaSR-induced STC2 was confirmed by interfering with STC2 expression in the presence of NPS R-568. RESULTS: The constitutive expression of STC2 was confirmed. STC2 mRNA and protein levels were increased by NPS R-568 with or without high phosphate. NPS-2143 resulted in decreased STC2 mRNA levels, but decreased STC2 protein levels were only found under the high-phosphate condition. Confocal microscopy demonstrated the colocalization of STC2 and plasma membrane or endoplasmic reticulum markers. STC2 overexpression reduced HAoSMCs apoptosis, which were reversed with STC2 silencing. NPS R-568 treatment reduced HAoSMCs apoptosis, but STC2 silencing abolished the protective effect. CONCLUSION: This is the first evidence that STC2 is regulated by CaSR in HAoSMCs. CaSR activation-induced STC2 has putative anti-apoptotic effects against high phosphate. Calcimimetics are promising agents to treat uremic vascular injury.

Low Parathyroid Hormone Versus Secondary Hyperparathyroidism and Survival in Patients Undergoing Hemodialysis: A Propensity-Matched Analysis.

Introduction: Low serum parathyroid hormone (PTH) and secondary hyperparathyroidism (SHPT) are very common in patients undergoing hemodialysis. However, it remains unclear which of these has a lower mortality. Objective: In this study, we compared outcomes between hemodialysis patients with low PTH and those with SHPT. Methods: This was a multi-center, retrospective, matched cohort study. Median intact PTH (iPTH) was used as the cutoff for allocating participants to low PTH (iPTH<100 pg/mL) and SHPT groups (iPTH ≥600 pg/mL). Sex, diabetes, age, and dialysis vintage were matched between the groups. The primary outcome was all-cause death at 72 months. Results: The study cohort comprised 2282 patients (1166 in each study group). Prior to matching, the primary outcome occurred in 429/1166 patients (36.79%) in the low PTH group and in 284/1116 (25.45%) in the SHPT group. There were no significant differences in all-cause death between the groups according to multivariable Cox regression (P=0.423). The hazard ratio for low PTH versus SHPT was 1.08 (95% confidence interval, 0.90-1.30). Propensity matching created 619 pairs of patients. Baseline characteristics, including age, sex, diabetes, and dialysis vintage were comparable between the groups. The primary outcome occurred in 195/619 patients (31.50%) in the low PTH group and in 193/619 (31.18%) in the SHPT group. There were no significant differences in all-cause death between the groups according to multivariable Cox regression (P=0.43). The adjusted hazard ratio for low PTH versus SHPT was 1.10 (95% confidence interval, 0.87-1.39). Conclusions: Hemodialysis patients with low PTH have similar all-cause death rates to the rates for those with SHPT.

Choroidal Vascularity Index Assessment: A Potential Noninvasive Technique for Diagnosing Diabetic Nephropathy.

AIMS: This study aimed to compare the accuracy of the choroidal vascularity index (CVI) and diabetic retinopathy (DR) in the diagnosis of diabetic nephropathy (DN). METHODS: We performed a cross-sectional study of 117 patients with proteinuria and diabetes mellitus (DM) in which 45 patients were diagnosed with DN by renal pathology. Demographic information, clinical features, and laboratory data were collected. A total of 234 eyes underwent evaluation of DR and the CVI using enhanced depth imaging-optical coherence tomography scans. We analyzed the association between the CVI and DN and compared the CVI and DR for diagnosing DN using area under receiver operating characteristic curves (AUROCs). RESULTS: The severe nonproliferative DR and proliferative DR groups showed a lower CVI than the no DR and mild/moderate nonproliferative DR groups (P < 0.01 or P < 0.001). There was a significantly lower CVI in patients with DN stage III (63.01% ± 1.47%) compared with those in DN stages IIa (62.1% ± 1.41%, P < 0.001) and IIb (59.85% ± 1.98%, P < 0.01). The sensitivity and specificity of the CVI for diagnosing DN were 84% (71%-94%) and 95% (88%-99%), respectively, which were preferable to those of DR. The AUROCs for the CVI and DR for diagnosing DN were 0.932 and 0.831, respectively. The CVI outperformed DR for diagnosing DN (P < 0.05). The cutoff value of the CVI was 63.13%. CONCLUSION: The CVI might be a reliable noninvasive technique for predicting the pathological stage of DN and is superior to DR in diagnosing DN.

The Efficacy of an Initial Prednisone Monotherapy Regimen on PLA2R-associated Idiopathic Membranous Nephropathy.

The aim of this study was to evaluate the efficacy and safety of prednisone monotherapy for phospholipase A2 receptor (PLA2R)-associated idiopathic membranous nephropathy (IMN). This was a retrospective cohort study involving 32 patients enrolled between January 2017 and June 2019 at Beijing Friendship Hospital, Capital Medical University, Beijing, China. Seventeen patients received prednisone monotherapy, and 15 received the Ponticelli regimen. The primary outcome was nephrotic syndrome remission at 12th month. The secondary outcomes were the incidence of adverse events and recurrence over the 12-month follow-up. At 12th month, 16/17 patients (94.1%) in the prednisone monotherapy group and 14/15 patients (93.3%) in the Ponticelli regimen group achieved remission (p = 0.19). The adverse events occurred in 9/17 and 9/15 of the patients receiving prednisone monotherapy and the Ponticelli regimen, respectively (p = 0.74). Four and three patients relapsed in the prednisone monotherapy and Ponticelli regimen groups, respectively (p = 0.99). Initial prednisone monotherapy had similar efficacy and safety compared with the Ponticelli regimen for PLA2R-associated IMN. Key Words: PLA2R-associated idiopathic membranous nephropathy, Ponticelli regimen, Prednisone monotherapy.

Bioinformatics analysis reveals the roles of cytoskeleton protein transgelin in occurrence and development of proteinuria.

BACKGROUND: Proteinuria is a sensitive hallmark for progressive renal dysfunction. Transgelin (TAGLN) has been demonstrated to participate in etiology of proteinuria and dynamics of podocyte foot process; however, the mechanism of TAGLN involvement in proteinuria is unknown. The present study aimed to explore the roles of TAGLN in the development of proteinuria. METHODS: Differentially expressed genes (DEGs) were detected from microarray expression profiling datasets from Gene Expression Omnibus, and analyzed by the short time series expression miner to cluster the DEGs in proteinuria progression. Kyoto Encyclopedia of Genes and Genomes pathway analysis was used to determine the top 20 enriched pathways, and construct a gene interaction network. RESULTS: In total, 2,409 DEGs for nephropathy and 10,612 DEGs for podocyte foot process and proteinuria were detected. Additionally, 76 common DEGs (25 upregulated and 41 downregulated) between nephropathy and podocyte foot process were primarily involved in innate immunity, positive regulation of transcription-DNA-templated, immunity and negative regulation of cell proliferation, enriched in cytokine-cytokine receptor interaction signaling pathway, Ras signaling pathway, axon guidance, tumor necrosis factor (TNF) signaling pathway and apoptosis. CONCLUSIONS: We discovered a TAGLN-mediated regulatory network involved in proteinuria progression. These findings provide novel insight to understand the molecular mechanisms underlying the pathogenesis of proteinuria.