Serum soluble LYVE1 is a promising non-invasive biomarker of renal fibrosis: a population-based retrospective cross-sectional study.

Diagnosis of renal fibrosis can only be verified by kidney biopsy, but biomarkers for non-invasive evaluation remain unsatisfactory. Patients with fibrosis often have abnormalities of the lymphatic vascular system and associated immune function. We describe here a lymphatic marker as a candidate biomarker for fibrosis. After assessing and grading the fibrosis scores, testing serum soluble lymphatic vessel endothelial hyaluronan receptor1 (sLYVE1) level, and collecting clinical information, the association between sLYVE1 and renal fibrosis was analyzed. Logistic regression analysis was used to screen variables. Diagnosis models with or without sLYVE1 were built, and nomograms were plotted. Calibration curve, C-index, and DCA were performed to assess the models. A total of 298 patients were enrolled in the study, of which 199 were included in the training cohort and 99 patients in the validation cohort. Serum sLYVE1 levels markedly elevated with increasing fibrosis grade (p<0.05). ROC analysis of sLYVE1 showed an AUC of 0.791 and 0.846 with optimal cut-off value of 405.25 ng/mL and 498.55 ng/mL for the prediction of moderate-to-severe renal fibrosis (MSF) and severe renal fibrosis (SF), respectively. The diagnostic nomogram model without sLYVE1 (model 1) included traditional clinical determinants (C-index: 0.658 for MSF; 0.603 for SF). A combination of model 1 and sLYVE1 (model 2) improved predictive performance (C-index: 0.847 for MSF; 0.856 for SF). Calibration curve and DCA demonstrated a better consistency accuracy and clinical benefit of model 2 than model 1. Serum sLYVE1 may be identified as a potential biomarker of renal fibrosis. Models incorporating sLYVE1 may be beneficial for a more accurate non-invasive diagnosis of renal fibrosis.

A case of Podocytic Infolding Glomerulopathy with SLE and literature review.

BACKGROUND: Podocytic infolding glomerulopathy (PIG) is a rare pathological change which was characterized by the microspheres or microtubular structures in the thickened glomerular basement membrane (GBM). Only a few dozen cases have been reported worldwide so far. Here we present a case of PIG with systemic lupus erythematosus. CASE PRESENTATION: A 61-year-old Chinese female was diagnosed with systemic lupus erythematosus with clinical manifestations of proteinuria, pleural effusion, seroperitoneum, anemia, leukopenia, thrombocytopenia, antinuclear antibody positive, and hypocomplementemia. She also had benign ovarian tumor and Epstein-Barr virus infection. Renal biopsy immunofluorescent staining showed IgM and C3 were granularly deposited along the capillary wall instead of typical "full house" features. Electron microscopy showed lots of microspheres structures were seen in the thickened GBM. CONCLUSION: We present a case of PIG in a patient with systemic lupus erythematosus. The mechanisms of PIG are unknown, but may be associated with connective tissue disease and podocyte injury.

Serum Lysyl Oxidase Is a Potential Diagnostic Biomarker for Kidney Fibrosis.

BACKGROUND: Kidney fibrosis is the ultimate consequence of advanced stages of chronic kidney disease (CKD); however, there are currently no reliable biomarkers or noninvasive diagnostic tests available for the detection of kidney fibrosis. Lysyl oxidase (LOX) promotes collagen cross-linking, and serum LOX levels have been shown to be elevated in patients with fibrosis of the heart, lungs, and liver. However, serum LOX levels have not been reported in patients with kidney fibrosis. We explored whether serum LOX levels are associated with kidney fibrosis. METHOD: Overall, 202 patients with kidney disease underwent renal biopsy, scoring of kidney fibrosis, and determination of the area of kidney fibrosis. LOX levels were measured in serum and in kidney tissues. We analyzed the association of circulating LOX and tissue LOX levels with the scores and areas of kidney fibrosis. LOX expression was also investigated with in vitro and in vivo kidney fibrosis models. RESULTS: Serum LOX levels were higher in patients with kidney fibrosis than in those without kidney fibrosis (p < 0.001) and higher in patients with moderate-severe kidney fibrosis than in patients with mild kidney fibrosis (p < 0.001). Both serum LOX and renal tissue LOX levels correlated with the area of kidney fibrosis (r = 0.748, p < 0.001; r = 0.899, p < 0.001, respectively). Receiver operating characteristic curve analysis of serum LOX levels showed an area under the curve of 0.80 (95% CI: 0.74-0.86). The optimal serum LOX level cutoff point was 253.34 pg/mL for the prediction of kidney fibrosis and 306.56 pg/mL for the prediction of moderate-severe kidney fibrosis. LOX expression levels were significantly upregulated (2.3-2.6 and 6-fold, respectively) in in vitro and in vivo interstitial fibrosis models. CONCLUSIONS: Both serum LOX and tissue LOX levels correlated with the presence and degree of kidney fibrosis in patients with CKD. These results suggest that serum LOX levels could potentially serve as a noninvasive diagnostic biomarker for kidney fibrosis and may further potentially serve as a stratified biomarker for the identification of mild and moderate-severe kidney fibrosis.

Long noncoding RNA-GAS5 retards renal fibrosis through repressing miR-21 activity.

BACKGROUND/AIMS: Long noncoding RNA (lncRNA) is a large and diverse class of RNA molecules, and has received widespread attention for its role in the regulation of various biological processes, including stem cell transformation, neurological disease, and tumorigenesis. However, the role of lncRNA in renal fibrosis remains unclear. METHODS: We investigated the expression of lncRNA-GAS5 by quantitative real-time polymerase chain reaction (PCR) or fluorescence in situ hybridization in chronic kidney disease (CKD) by designing both in vivo and in vitro experiments. With over-expression of GAS5 or knockdown GAS5, miR-21 and its downstream target genes were tested using quantitative real-time PCR or western blots. Mutants of miR-21 were designed and transfected in cells. GAS5 in the plasma and urine of patients with CKD was measured by quantitative real-time PCR. RESULTS: In normal rats, GAS5 was predominantly expressed in renal tubular epithelial cells. GAS5 induction was significantly reduced in obstructive kidneys at 7 days after unilateral ureteral obstruction. In vitro, GAS5 was inhibited in cultured normal rat renal proximal tubular cells (NRK-52E) after incubation with transforming growth factor ß at 24 h. Ectopic over-expression of GAS5 repressed extracellular matrix (ECM) levels such as collagen type III and fibronectin 1. Conversely, knockdown GAS5 augmented ECM accumulation in NRK-52E cells. GAS5 suppressed miR-21 activity in a direct and mechanistic manner. It subsequently turned off the expression of miR-21 downstream target genes, matrix metallopeptidase 2 and 9, which resulted in excessive ECM synthesis and deposition. Of note, plasma GAS5 was positively correlated with estimated glomerular filtration rate levels in CKD patients with different etiologies while urine GAS5 was negatively correlated. CONCLUSION: Activation of lncRNA-GAS5 attenuates kidney fibrosis by modulating miR-21 activity and may serve as a surrogate biomarker in monitoring CKD progression.

Effects of polyethylene glycol 2 L alone or with ascorbic acid compared with polyethylene glycol 4 L alone for bowel preparation before colonoscopy: protocol for a systematic review and network meta-analysis.

INTRODUCTION: Colonoscopy has been regarded as a standard method of detecting and removing gastrointestinal lesions early, while adequate bowel preparation is the prerequisite of determining the diagnostic accuracy and treatment safety of this process. Polyethylene glycol (PEG) based bowel preparation regimens remain the first recommendation, but the optimal option is still uncertain. The aim of this systematic review and network meta-analysis of randomised controlled trials (RCTs) is to determine the optimal PEG based bowel preparation regimen before colonoscopy. METHODS AND ANALYSIS: We will assign two investigators to independently search all potential citations, screen records, abstract essential information and appraise the risk of bias accordingly. Then, random effects pairwise and network meta-analyses of RCTs comparing PEG 2 L alone or with ascorbic acid with PEG 4 L alone will be performed using RevMan 5.3 (Copenhagen, Denmark: The Nordic Cochrane Centre, The Cochrane Collaboration, 2013), Stata 14 (StataCorp, Texas, USA) and WinBUGS 1.4 (Imperial College School of Medicine, St Mary's, London, UK) from January 2000 to April 2017. The surface under the cumulative ranking curve will also be calculated in order to rank the regimens. ETHICS AND DISSEMINATION: Ethics approval and patient written informed consent will not be required because all of the analyses in the present study will be performed based on data from published studies. We will submit our systematic review and network meta-analysis to a peer reviewed scientific journal for publication. SYSTEMATIC REVIEW REGISTRATION: PROSPERO: CRD42017068957.

ß-Arrestin-biased AT1R stimulation promotes extracellular matrix synthesis in renal fibrosis.

The renin-angiotensin system plays a critical role in the progression of renal fibrosis. Angiotensin II type 1 receptor (AT1R) belongs to the B family of the G protein-coupled receptor (GPCR) family. ß-Arrestins are known as negative regulators of GPCRs. Recently, ß-arrestins have been found to regulate multiple intracellular signaling pathways independent of G proteins. In this study we investigated the role of ß-arrestins in regulating extracellular matrix (ECM) synthesis in renal fibrosis. The rat kidney fibroblast cell line (NRK-49F) was treated with the ß-arrestin biased agonist [1-sar, 4, 8-ile]angiotensin II (SII), which does not initiate AT1R-G protein signaling. The cells were transfected with recombinant adenoviruses expressing ß-arrestin-2 gene or small-interfering RNA (siRNA) targeting ß-arrestin-2. The unilateral ureteral obstruction (UUO) model was used in vivo. mRNA and protein levels of ß-arrestin-2, not ß-arrestin-1, were significantly upregulated in the UUO kidney tissues. SII induced the tight binding of ß-arrestin-2 with AT1R. SII increased the synthesis of collagen I and fibronectin in NRK-49F, which were abolished when pretreated with candesartan (AT1R blocker). Transfection of siRNA targeting ß-arrestin-2 decreased the effects of SII on ECM synthesis. Overexpression of ß-arrestin-2 enhanced SII-stimulated ECM synthesis. SII induced ERK1/2 phosphorylation in NRK-49F. Transfection of siRNA targeting ß-arrestin-2 inhibited ERK phosphorylation. Overexpression of ß-arrestin-2 increased ERK1/2 phosphorylation. Our study first showed that AT1R-ß-arrestin-2 pathway signaling plays an important role in renal fibrosis, although it was previously believed that the AT1R-G protein pathway plays a major role. Targeting ß-arrestin-2 may be a potential therapeutic agent for renal fibrosis.

Candesartan inhibits LPS-induced expression increase of toll-like receptor 4 and downstream inflammatory factors likely via angiotensin II type 1 receptor independent pathway in human renal tubular epithelial cells.

The present study was to determine whether candesartan, an angiotensin II type 1 receptor blocker (ARB), exerts anti-inflammatory effects through inhibiting the toll-like receptor 4 (TLR4) pathway in human renal tubular epithelial cells (HKCs). The experiments were carried on cultured HKCs. By means of flow cytometry, Western blot, RT-PCR and ELISA techniques, the TLR4 protein, angiotensin II type 1 receptor (AT1R) and phosphorylated nuclear factor-kappa B (NF-κB) p65 protein level, mRNA levels of macrophage chemoattractant protein-1 (MCP-1) and regulated upon expression normal T cell expressed and secreted (RANTES), as well as MCP-1 and RANTES protein concentrations in conditioned media were measured. The results showed that lipopolysaccharide (LPS) upregulated the TLR4 protein level in cultured HKCs. Application of LPS increased NF-κB activation and induced release of its downstream inflammatory factors including MCP-1 and RANTES. Candesartan reversed LPS-induced upregulation of TLR4 expression, inhibited NF-κB activation, and reduced MCP-1 and RANTES release. However, knockdown on AT1R by siRNA did not change those previous effects of candesartan. These results suggest that candesartan-induced anti-inflammatory effect may be through a novel pathway, independent of AT1R.