Renalase regulates renal tubular injury in diabetic nephropathy via the p38MAPK signaling pathway.

Diabetic nephropathy (DN) is an important complication of diabetes and the leading cause of end-stage renal disease globally. Renal tubular damage occurs to varying degrees in the early stages of DN prior to glomerular damage. Renalase (RNLS) is an amine oxidase, which is produced and secreted by the renal tubular epithelial cells. RNLS is reportedly closely related to renal tubular injury in acute and chronic kidney diseases. Herein, we aimed to evaluate the changes in tubular RNLS expression in DN and its correlation with DN-associated renal tubular injury. Conditional permanent renal tubular epithelial rat-cell line NRK-52E was transfected with pcDNA3-RNLS plasmid or administered recombinant rat RNLS protein and high glucose (HG) dose. A total of 22 adult Sprague-Dawley rats were randomly divided into the control (CON, n = 10) or diabetic nephrology (DN, n = 12) group. Random blood glucose levels of the rats were measured by sampling of the caudal vein weekly. After 8 weeks, the rat's body weight, 24-h urinary albumin concentration, and right kidney were evaluated. Our study suggested the decreased expression levels of RNLS in renal tissue and renal tubular epithelial cells in DN rats, accompanied by renal tubulointerstitial fibrosis, apoptosis of renal tubular epithelial cells, and activation of the p38MAPK signal pathway. Reversing the low RNLS expression can reduce the level of p38MAPK phosphorylation and delay renal tubular injury. Thus, the reduction of renal tubular RNLS expression in DN mediates tubulointerstitial fibrosis and cell apoptosis via the activation of the p38MAPK signal pathway. RNLS plays a key mediating role in DN-associated tubular injury via p38MAPK, which provides new therapeutic targets and a theoretical basis for early prevention and treatment of DN.

Characterization of Heterogeneity and Dynamics of Lysis of Single Bacillus subtilis Cells upon Prophage Induction During Spore Germination, Outgrowth, and Vegetative Growth Using Raman Tweezers and Live-Cell Phase-Contrast Microscopy.

A prophage comprises a bacteriophage genome that has integrated into a host bacterium's DNA, which generally permits the cell to grow and divide normally. However, the prophage can be induced by various stresses, or induction can occur spontaneously. After prophage induction, viral replication and production of endolysins begin until the cell lyses and phage particles are released. However, the heterogeneity of prophage induction and lysis of individual cells in a population and the dynamics of a cell undergoing lysis by prophage induction have not been fully characterized. Here, we used Raman tweezers and live-cell phase-contrast microscopy to characterize the Raman spectral and cell length changes that occur during the lysis of individual Bacillus subtilis cells from spores that carry PBSX prophage during spores' germination, outgrowth, and then vegetative growth. Major findings of this work are as follows: (i) After addition of xylose to trigger prophage induction, the intensities of Raman spectral bands associated with nucleic acids of single cells in induced cultures gradually fell to zero, in contrast to the much smaller changes in protein band intensities and no changes in nucleic acid bands in uninduced cultures; (ii) the nucleic acid band intensities from an individual induced cell exhibited a rapid decrease, following a long lag period; (iii) after the addition of nutrient-rich medium with xylose, single spores underwent a long period (228 ± 41.4 min) for germination, outgrowth, and vegetative growth, followed by a short period of cell burst in 1.5 ± 0.8 min at a cell length of 8.2 ± 5.5 µm; (iv) the latent time (Tlatent) between the addition of xylose and the start of cell burst was heterogeneous in cell populations; however, the period (ΔTburst) from the latent time to the completion of cell lysis was quite small; (v) in a poor medium with l-alanine alone, addition of xylose caused prophage induction following spore germination but with longer Tlatent and ΔTburst times and without cell elongation; (vi) spontaneous prophage induction and lysis of individual cells from spores in a minimal nutrient medium were observed without xylose addition, and cell length prior to cell lysis was ∼4.1 µm, but spontaneous prophage induction was not observed in a rich medium; (vii) in a rich medium, addition of xylose at a time well after spore germination and outgrowth significantly shortened the average Tlatent time. The results of this study provide new insights into the heterogeneity and dynamics of lysis of individual B. subtilis cells derived from spores upon prophage induction.

Prophylactic atorvastatin prior to intra-arterial administration of iodinated contrast media for prevention of contrast-induced acute kidney injury: A meta-analysis of randomized trial data
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BACKGROUND: The efficacy of high-dose atorvastatin pretreatment in reducing the incidence of contrast-induced nephropathy in patients undergoing coronary angiography (CAG) or percutaneous coronary intervention (PCI) has been examined in some randomized studies. However, the results across the trials remain controversial. OBJECTIVE: This study sought to perform a meta-analysis to evaluate the effect of high-dose atorvastatin in the prevention of contrast-induced nephropathy (CIN) while undergoing CAG or PCI. MATERIALS AND METHODS: Comprehensive literature searches for randomized controlled trials (RCTs) comparing high-dose atorvastatin vs. low-dose statin or placebo pretreatment for prevention of contrast-induced acute kidney injury in patients undergoing CAG were performed using PubMed, Embase, and the Cochrane library updated to June 2017. The primary outcome was the incidence of CIN. RESULTS: A total of 11 RCTs were included in this analysis. The high-dose atorvastatin treatment can significantly reduce the incidence of CIN (OR 0.46, 95% CI 0.35 - 0.62, p < 0.00001). The benefit was consistent in comparison with the low-dose group (OR 0.41, 95% CI 0.25 - 0.66, p = 0.0003) and the placebo group (OR 0.50, 95% CI 0.26 - 0.98, p = 0.04). CONCLUSION: Our study demonstrates that high-dose statin pretreatment shows a benefit specifically in reducing the incidence of contrast-induced acute kidney injury in patients undergoing CAG, especially compared with low-dose statin pretreatment.

PGC-1α Protects from Notch-Induced Kidney Fibrosis Development.

Kidney fibrosis is the histologic manifestation of CKD. Sustained activation of developmental pathways, such as Notch, in tubule epithelial cells has been shown to have a key role in fibrosis development. The molecular mechanism of Notch-induced fibrosis, however, remains poorly understood. Here, we show that, that expression of peroxisomal proliferation g-coactivator (PGC-1α) and fatty acid oxidation-related genes are lower in mice expressing active Notch1 in tubular epithelial cells (Pax8-rtTA/ICN1) compared to littermate controls. Chromatin immunoprecipitation assays revealed that the Notch target gene Hes1 directly binds to the regulatory region of PGC-1α Compared with Pax8-rtTA/ICN1 transgenic animals, Pax8-rtTA/ICN1/Ppargc1a transgenic mice showed improvement of renal structural alterations (on histology) and molecular defect (expression of profibrotic genes). Overexpression of PGC-1α restored mitochondrial content and reversed the fatty acid oxidation defect induced by Notch overexpression in vitro in tubule cells. Furthermore, compared with Pax8-rtTA/ICN1 mice, Pax8-rtTA/ICN1/Ppargc1a mice exhibited improvement in renal fatty acid oxidation gene expression and apoptosis. Our results show that metabolic dysregulation has a key role in kidney fibrosis induced by sustained activation of the Notch developmental pathway and can be ameliorated by PGC-1α.

Meta-analysis of the efficacy and safety of nucleotide/nucleoside analog monotherapy for hepatitis B virus-associated glomerulonephritis.

BACKGROUND/AIMS: Antiviral monotherapy is recommended for hepatitis B virus-associated glomerulonephritis (HBV-GN) treatment. Although considered superior to interferon-α in several respects, nucleotide/nucleoside analog (NA) monotherapy has not been studied. This metaanalysis evaluates the efficacy and safety of NA monotherapy for treating HBV-GN. METHODS: We searched for controlled clinical trials of NA monotherapy for HBVGN in the MEDLINE, Embase, Cochrane Library, Chinese BioMedical Literature on disc, Chinese National Knowledge Infrastructure, and Wanfang databases. Primary outcome measures were proteinuria remission, HBV-DNA negative conversion rate, and hepatitis B e-antigen (HBeAg) clearance. Secondary outcome measures were variations in proteinuria, serum albumin, alanine aminotransferase (ALT), and serum creatinine (Scr). RESULTS: Ten trials involving 325 patients were included: four randomized controlled trials, two cohort clinical trials, and four self-controlled studies. Based on the fixed-effects model, we found significant proteinuria remission rate improvement in the NA group (relative risk (RR): 3.60, 95% confidence interval (CI): 1.99 – 6.50), negative conversion rate of HBV-DNA (RR: 2.20, 95% CI: 1.55 – 3.13), and clearance of HBeAg (RR: 4.49, 95% CI: 1.29 – 15.67). Improvement in ALT (mean difference (MD): 56.60, 95% CI: 50.41 – 62.79) was found with the fixedeffects model, and a slight decrease in Scr (MD: 25.25, 95% CI: –17.11 – 67.61, p = 0.24) was shown. CONCLUSIONS: HBV-GN proteinuria remission with elevated serum albumin, decreased HBV replication, and improved HBeAg clearance could be achieved using NA monotherapy. Furthermore, NA monotherapy may protect renal function in HBV-GN patients by preventing Scr elevation.

Efficacy and safety of paricalcitol in patients undergoing hemodialysis: a meta-analysis.

BACKGROUND: The elevated calcium and phosphorus levels in patients undergoing hemodialysis may increase the risk of all-cause mortality. Paricalcitol, as a new vitamin D receptor activator (VDRA), seemed to be effective in reducing the calcium and phosphorus levels. OBJECTIVES: The aim of this study was to compare the efficacy and safety of paricalcitol with other VDRAs in patients undergoing hemodialysis. METHODS: PubMed, Embase, and Web of Science database were systematically reviewed. SELECTION CRITERIA: Studies that focused on the use of paricalcitol for hemodialysis patients were eligible for inclusion. DATA COLLECTION AND ANALYSIS: Two independent investigators performed the literature search, data extraction, and assessment of methodological quality. The outcomes were expressed with standard mean difference (SMD), HR, or risk ratio (RR) with 95% CI. RESULTS: Thirteen studies involving 112,695 patients were included in this meta-analysis. Among these studies, four studies were cohort studies and nine studies were randomized controlled trials (RCTs). For cohort studies, they were regarded as being of high quality; for RCTs, only one was classified as being at low risk of bias; and the remaining eight studies were at being unclear risk of bias. Compared with other VDRAs, paricalcitol significantly improved the overall survival (HR =0.86, 95% CI: 0.80, 0.92; P<0.001) and reduced the intact parathyroid hormone (iPTH) (SMD =-0.53, 95% CI: -0.90, -0.17; P=0.004). Paricalcitol offered similar effect with other VDRAs in the control of calcium (SMD =0.32, 95% CI: -0.04, 0.67; P=0.078) and phosphorus (SMD =0.06, 95% CI: -0.26, 0.37; P=0.727) levels. However, the serum change in calcium phosphate product was greater in the paricalcitol group than in the other VDRA group (SMD =2.13, 95% CI: 0.19, 4.07; P=0.031). There was no significant difference in the incidence of adverse events between the two groups (RR =1.02, 95% CI: 0.93, 1.12; P=0.674). CONCLUSION: Paricalcitol was crucial in reducing the mortality in patients undergoing hemodialysis. Moreover, both paricalcitol and other VDRAs were effective in control of the serum iPTH, calcium, and phosphorus levels. Given the potential limitations in this study, more prospective large-scale, well-conducted RCTs are needed to confirm these findings.

Efficacy of atorvastatin on the prevention of contrast-induced acute kidney injury: a meta-analysis.

BACKGROUND: Results of studies on the efficacy of atorvastatin pretreatment on reducing the prevalence of contrast-induced acute kidney injury (CIAKI) in patients undergoing coronary angiography (CAG) or percutaneous coronary intervention (PCI) have been controversial. OBJECTIVE: We undertook a meta-analysis to evaluate the efficacy of atorvastatin on contrast-induced nephropathy (CIN) after CAG or PCI. MATERIALS AND METHODS: We undertook a systematic search of electronic databases (PubMed, Embase, and the Cochrane Library) up to June 2017. A meta-analysis was carried out including randomized controlled trials (RCTs) that compared atorvastatin pretreatment with pretreatment with a low-dose statin or placebo for CIAKI prevention in patients undergoing CAG. The main endpoint was CIN prevalence. RESULTS: Nine RCTs were included in our meta-analysis. Atorvastatin pretreatment reduced the prevalence of CIN significantly (odds ratio [OR] 0.46; 95% confidence interval [95% CI] 0.27-0.79; p=0.004). The benefit of high-dose atorvastatin pretreatment was consistent when compared with the control group (OR 0.45; 95% CI 0.21-0.95; p=0.04). CONCLUSION: At high doses, atorvastatin pretreatment was associated with a significant reduction in the prevalence of CIAKI in patients undergoing CAG. Pretreatment with high-dose atorvastatin could be employed to prevent CIAKI.

p16ink4a Expression Is Increased through 12-Lipoxygenase in High Glucose-Stimulated Glomerular Mesangial Cells and Type 2 Diabetic Glomeruli.

BACKGROUND/AIMS: Arachidonic acid-metabolizing enzyme, 12-lipoxygenase (12-LO), is involved in the glomerular hypertrophy of diabetic nephropathy (DN), in which cyclin-dependent kinase inhibitors (CKIs) play important roles. However, it is unclear whether 12-LO regulates the expression of the CKI p16(ink4a) in DN. METHODS: Primary glomerular mesangial cells (MCs) and glomeruli isolated from rats were used in this study. The rats were fed a high-fat diet and given low-dose streptozotocin to induce type 2 diabetes. The 12-LO product, 12(S)-hydroxyeicosatetraenoic acid (12(S)-HETE), was infused through an osmotic minipump. Enzyme-linked immunosorbent assay, Western blot, and morphometric analyses were performed. RESULTS: High glucose (HG) increased the p16(ink4a) protein expression in MCs, but this increase was prevented by the 12-LO inhibitor, cinnamyl-3,​4-dihydroxy-α-cynanocinnamate (CDC). The levels of p-p38MAPK and p16(ink4a) in MCs were significantly elevated after the 12(S)-HETE treatment, whereas the p38MAPK inhibitor SB203580 prevented these increases. Compared with levels in control MCs, marked increases in p38MAPK activation and p16(ink4a) expression were observed in MCs plated on collagen IV, while the CDC treatment prevented these changes. Subcutaneous injection of CDC did not affect glucose levels, but completely attenuated the diabetes-related increases in the 12(S)-HETE content, p16(ink4a) expression, p-p38MAPK levels, glomerular volume, and the kidney/body weight ratio. Compared with levels in controls, p16(ink4a) and p-p38MAPK in the glomeruli derived from 12(S)-HETE-treated rats were significantly higher. CONCLUSIONS: 12-LO-p38MAPK mediates the upregulation of p16(ink4a) in HG-stimulated MCs and type 2-diabetic glomeruli, and new therapies aimed at 12-LO inhibition may prove beneficial in ameliorating diabetes-induced glomerular hypertrophy.

Unusual ceria dispersion formed in confined space: a stable and reusable adsorbent for aromatic sulfur capture.

An unusual ceria dispersion was achieved by using the confined space between template and silica walls in as-prepared mesoporous silica, for the first time. The new adsorbents exhibit high adsorptive desulfurization activity and, more importantly, excellent stability and reusability, which is impossible to realize with conventional adsorbents.