Indoxyl Sulfate Aggravates Podocyte Damage through the TGF-ß1/Smad/ROS Signalling Pathway.

INTRODUCTION: Hyperglycaemia induces the production of a large quantity of reactive oxygen species (ROS) and activates the transforming growth factor ß1 (TGF-ß1)/Smad signalling pathway, which is the main initiating factor in the formation of diabetic nephropathy. Indoxyl sulphate (IS) is a protein-binding gut-derived uraemic toxin that localizes to podocytes, induces oxidative stress, and inflames podocytes. The involvement of podocyte damage in diabetic nephropathy through the TGF-ß1 signalling pathway is still unclear. METHODS: In this study, we cultured differentiated rat podocytes in vitro and measured the expression levels of nephrin, synaptopodin, CD2AP, SRGAP2a, and α-SMA by quantitative real-time PCR (qRT-PCR) and Western blotting after siRNA-mediated TGF-ß1 silencing, TGF-ß1 overexpression, and the presence of the ROS inhibitor acetylcysteine. We detected the expression levels of nephrin, synaptopodin, CD2AP, SRGAP2a, small mother against decapentaplegic (Smad)2/3, phosphorylated-Smad2/3 (p-Smad2/3), Smad7, NADPH oxidase 4 (NOX4), and ROS levels under high glucose (HG) and IS conditions. RESULTS: The results indicated that nephrin, synaptopodin, CD2AP, and SRGAP2a expressions were significantly upregulated, and α-SMA expression was significantly downregulated in the presence of HG under siRNA-mediated TGF-ß1 silencing or after the addition of acetylcysteine. However, in the presence of HG, the expressions of nephrin, synaptopodin, CD2AP, and SRGAP2a were significantly downregulated, and the expression of α-SMA was significantly upregulated with the overexpression of TGF-ß1. IS supplementation under HG conditions further significantly reduced the expressions of nephrin, synaptopodin, CD2AP, and SRGAP2a; altered the expressions of Smad2/3, p-Smad2/3, Smad7, and NOX4; and increased ROS production in podocytes. CONCLUSION: This study suggests that IS may modulate the expression of nephrin, synaptopodin, CD2AP, and SRGAP2a by regulating the ROS and TGF-ß1/Smad signalling pathways, providing new theoretical support for the treatment of diabetic nephropathy.

Assessment of urinary podocalyxin as an alternative marker for urinary albumin creatinine ratio in early stage of diabetic kidney disease in older patients.

This study's objective is to evaluate the correlation relationship between Podocalyxin (PCX), an urinary marker of podocytes, urinary albumin-creatinine ratio (ACR) and the predictive value of PCX in the routine screen of early diabetic kidney disease (DKD) among older people. We also aimed to explore its prediction value despite of other metabolic factor and how PCX alters in the predictive power for early stage of diabetic nephropathy. In retrospective, 320 cases of older patients diagnosed with type 2 diabetes mellitus who met both inclusion and exclusion criteria were collected and divided with levels of urinary albumin, that is, normal albuminuria group, microalbuminuria group and healthy group. The correlation coefficient between PCX and ACR, and the odds ratio of PCX were gauged in the study. Area under the receiver operating characteristic (ROC) curve was also calculated. There were 188 patients in the normal group with urine ACR<30mg/g, and 132 patients in the microproteinuria group with urine ACR 30-300mg/g. 132 cases of DKD diagnosed with ACR, among them, 104 cases of DKD were predicted by PCX. The percentage correction value was 78.8%. The following parameters such as gender, age, course of disease, glycated hemoglobin, triglyceride, total cholesterol, BMI, blood pressure, uric acid, and eGFR were used as variables for adjustment to establish the prediction model of urine PCX and ACR. Multiple logistic regression test was carried out to evaluate against the predictive ability of the model. The area under the ROC curve corresponding to the regression model after adjustment is 0.952. Although factors such as the course of disease, HbA1C, UA, and eGFR could influence on the predictive ability of PCX, PCX still has a good ability to predict early DKD in older patients. Therefore, it could be used as a diagnostic indicator for early-stage DKD in older patients.

Fibrinogen-to-albumin ratio is related to the severity of coronary artery disease in chronic kidney disease patients undergoing coronary angiography.

OBJECTIVES: This study was to explore the potential relationship between the fibrinogen-to-albumin ratio (FAR) and the presence and severity of coronary artery disease (CAD) in stage 3-5 predialysis chronic kidney disease (CKD) patients. DESIGN: This study included 978 patients undergoing coronary angiography (CAG). CAD was defined as the presence of obstructive stenosis>50% of the lumen diameter in any of the four main coronary arteries. Gensini scores (GSs), left main coronary artery (LMCA) and three-vessel coronary artery disease (TVD) were used to elevate the severity of CAD. RESULTS: The adjusted odds ratios of CAD were 3.059 (95% CI: 1.859-5.032) and 2.670 (95% CI: 1.605-4.441) in the third and fourth quartiles of FAR compared with the first quartile, respectively. Among 759 patients diagnosed with CAD, multivariate logistic regression analysis showed that FAR (at the 0.01 level) was significantly positively associated with the presence of LMCA (adjusted OR=1.177, 95% CI 1.067-1.299, P=0.001) or TVD (adjusted OR=1.154, 95% CI 1.076-1.238, P<0.001), and a higher GS (adjusted OR=1.152, 95% CI 1.073-1.238, P<0.001). CONCLUSIONS: FAR levels were independently associated with the presence and severity of CAD in stage 3-5 predialysis CKD patients.

Inhibition of PI3K/AKT/mTOR Signalling Pathway Activates Autophagy and Suppresses Peritoneal Fibrosis in the Process of Peritoneal Dialysis.

Peritoneal dialysis (PD) is an important part of replacement therapy for kidney failure. However, long-term PD treatment can cause peritoneal fibrosis. Autophagy may be involved in the pathological mechanism of peritoneal fibrosis (PF). Although autophagy is currently known to be involved in course of PF, its specific effects still lack in-depth research. In this experiment, a high-glucose (HG)-induced peritoneal fibrosis rat model was successfully established via intraperitoneal injection of HG peritoneal dialysate, and the phosphatidylinositol 3-kinase (PI3K) inhibitor LY294002 and the mechanistic target of rapamycin (mTOR) inhibitor rapamycin were used to treat peritoneal fibrosis rats. In addition, in vitro studies of high glucose-induced peritoneal fibrosis were performed using rat peritoneal mesothelial cells (PMCs). In vivo and in vitro experiments showed that LY294002 and rapamycin effectively inhibited the process of PF induced by high glucose. In addition, LY294002 and rapamycin were found to alleviate fibrosis by eliminating intracellular reactive oxygen species (ROS) levels, promoting the expression of the epithelial mesenchymal transdifferentiation proteins zonula occludens-1 (ZO-1) and E-cadherin, and inhibiting the expression of p-PI3K, PI3K, p-mTOR, mTOR, the fibroblast-specific proteins ferroptosis suppressor protein 1 (FSP1), and alpha-smooth muscle actin (α-SMA). Moreover, LY294002 and rapamycin promoted expression of autophagy-related proteins LC3-II/I, p62, and beclin-1. The current data indicated that inhibition of PI3K/AKT/mTOR signalling pathway activated autophagy and suppressed PF in the process of PD. Therefore, intervention in this signalling pathway may become a research goal for the prevention and treatment of PF, which has important clinical significance.

Treatment Effect of Regional Sodium Citrate Anticoagulation in Elderly Patients With High-Risk Bleeding Receiving Continuous Renal Replacement Therapy.

OBJECTIVE: To investigate the safety and efficacy of regional citrate anticoagulation (RCA) on elderly patients at high risk of bleeding after continuous renal replacement therapy (CRRT). METHODS: A total of 31 patients at high risk of bleeding who received CRRT in the intensive care unit were collected. The patients were divided into RCA group (n = 17) and no anticoagulation group (NA, n = 14) according to whether RCA was used or not. The levels of creatinine (Cr), blood urea nitrogen (BUN), prothrombin time (PT), activated partial thromboplastin time (APTT), total calcium (tCa), ionized calcium ion (iCa2+), sodium ion (Na+), bicarbonate ion (HCO3-), tCa/iCa2+ ratio, and pH were observed after treatment. The filter use time, number of filters used, filter obstruction events, clinical outcomes, and safety evaluation indexes were compared post-treatment. RESULTS: After treatment, serum Cr and BUN levels, APTT and PT levels in the RCA group were significantly lower than the NA group. The tCa, iCa2+, HCO3-, tCa/iCa2+, and pH were within the normal range after RCA treatment while Na+ levels saw a significant increase. In the RCA group, the filter using time was significantly longer, with significantly reduced numbers of filter use within 72 h and filter disorder events. Additionally, patients in the RCA group showed significant recovery of renal function and a significant reduction in bleeding events and in-hospital mortality. CONCLUSION: RCA treatment significantly improves clinical outcome of patients at high risk of bleeding after CRRT, safely and effectively prolongs the filter life and avoids coagulation incidences.

ScAOC1, an allene oxide cyclase gene, confers defense response to biotic and abiotic stresses in sugarcane.

KEY MESSAGE: An allene oxide cyclase gene which is involved in defense against biotic and abiotic stresses was cloned and characterized in sugarcane. Allene oxide cyclase (AOC), a key enzyme in jasmonate acid (JA) biosynthesis, affects the stereoisomerism and biological activity of JA molecules, and plays an important role in plant stress resistance. In this study, four SsAOC alleles (SsAOC1-SsAOC4), which shared similar gene structure and were located on Chr1A, Chr1B, Chr1C, and Chr1D, respectively, were mined from sugarcane wild species Saccharum spontaneum, and a homologous gene ScAOC1 (GenBank Accession Number: MK674849) was cloned from sugarcane hybrid variety Yacheng05-179 inoculated with Sporisorium scitamineum for 48 h. ScAOC1 and SsAOC1-SsAOC4 were alkaline, unstable, hydrophilic, and non-secretory proteins, which possess the same set of conserved motifs and were clustered into one group in the phylogenetic analysis. ScAOC1 was expressed in all sugarcane tissues, but with different levels. After infection by S. scitamineum, the transcripts of ScAOC1 were increased significantly both in the smut-susceptible (ROC22) and resistant (Yacheng05-179) varieties, but its transcripts were more accumulated and lasted for a longer period in the smut-resistant variety than in the smut-susceptible one. ScAOC1 was down-regulated under MeJA and NaCl treatments, but up-regulated under SA, ABA, PEG, and cold stresses. Transiently overexpressing ScAOC1 gene into Nicotiana benthamiana leaves regulated the responses of N. benthamiana to two pathogens Ralstonia solanacearum and Fusarium solani var. coeruleum. Furthermore, prokaryotic expression analysis showed overexpression of ScAOC1 in Escherichia coli BL21 could enhance its tolerance to NaCl, mannitol, and cold stimuli. These results indicated that ScAOC1 may play an active role in response to biotic and abiotic stresses in sugarcane.