Degree Of Renal Interstitial Fibrosis Research Articles

Microvesicles from Mesenchymal Stem CellsOverexpressing MiR-34a Ameliorate Renal Fibrosis In Vivo.

We recently discovered that microvesicles (MVs) derived from mesenchymal stem cells (MSCs) overexpressing miRNA-34a can alleviate experimental kidney injury in mice. In this study, we further explored the effects of miR34a-MV on renal fibrosis in the unilateral ureteral obstruction (UUO) models. Methods. Bone marrow MSCs were modified by lentiviruses overexpressing miR-34a, and MVs were collected from the supernatants of MSCs. C57BL6/J mice were divided into control, unilateral ureteral obstruction (UUO), UUO + MV, UUO + miR-34aMV and UUO + miR-34a-inhibitor-MV groups. MVs were injected to mice after surgery. The mice were then euthanized on day 7 and 14 of modeling, and renal tissues were collected for further analyses by Hematoxylin and eosin, Masson's trichrome, and Immunohistochemical (IHC) staining. Results. The UUO + MV group exhibited a significantly reduced degree of renal interstitial fibrosis with inflammatory cell infiltration, tubular epithelial cell atrophy, and vacuole degeneration compared with the UUO group. Surprisingly, overexpressing miR-34a enhanced these effects of MSC-MV on the UUO mice. Conclusion. Our study demonstrates that miR34a further enhances the effects of MSC-MV on renal fibrosis in mice through the regulation of epithelial-to-mesenchymal transition (EMT) and Notch pathway. miR-34a may be a candidate molecular therapeutic target for the treatment of renal fibrosis. DOI: 10.52547/ijkd.7673.

Sinomenine improves renal fibrosis by regulating mesenchymal stem cell-derived exosomes and affecting autophagy levels.

This study attempts to investigate the therapeutic effect of sinomenine on renal fibrosis and its mechanism. The 8-week-old C57BL/6 male mice were randomly divided into sham group, UUO model group, UUO sinomenine group (UUO + Sino 50), UUO + sinomenine group (UUO + Sino 100), UUO + exosome group (exo), and UUO + exo-inhibitor. The pathological changes of kidney were observed by H&E staining, the degree of renal interstitial fibrosis was detected by MASSON and Sirius red staining, and the expressions of fibrosis and autophagy markers were detected by real-time fluorescence quantitative PCR and WB. NTA and electron microscopy were used to analyze exo secretion after sinomenine treatment. Sinomenine could improve the progression of renal fibrosis without causing tissue damage including heart, lungs and liver. Sinomenine could promote autophagosome formation. It could promote the secretion of exosomes from bone marrow mesenchymal stem cells (BMSCs). Sinomine regulates the PI3K-AKT pathway through BMSC-exo carrying miR-204-5p, affecting autophagy level and alleviating the process of renal fibrosis. Our study suggests that sinomine could improve the progression of renal fibrosis by influencing the expression of miR-204-5p in BMSC-exo and regulating the PI3K-AKT pathway.

The Effect of Body Mass Index on the Degree of Renal Interstitial Fibrosis and Tubular Atrophy - A Retrospective Case-Control Study

IntroductionThe degree of interstitial fibrosis and tubular atrophy (IFTA) seen on kidney biopsy has long been used to judge the chronicity of kidney disease to predict renal disease outcomes and prognosis. It is an essential component incorporated in many renal disease prognostic classification systems on the native and renal allograft. The impact of increased body mass index on the body metabolism, and the human vascular system, including the functional unit of the kidney, the nephron, is well-addressed in the literature. In this study, we focus on evaluating the degree of IFTA concerning the patient's body mass index (BMI).MethodAll the specimens of nephrectomies performed in King Abdulaziz University Hospital for adults from January 2010 to February 2021 were evaluated for this study. A total of 125 cases were selected for the study. The glass slides were pulled and assessed for the degree of IFTA. The demographic data, and the patient's BMI, were collected from the hospital records.ResultsSubjects with high BMI showed a 1.62 (OR: 1.62, 95% CI: 0.62, 4.22) and 1.52 (AOR: 1.52, 95% CI: 0.56, 4.13) increased risk of high IFTA score compared with those with normal BMI. This study has proved that only at a BMI of 25 or more will there be a measurable, independent effect on the degree of IFTA.ConclusionAlthough a small number of hospital-based populations limits this study, it could prove the increased severity of IFTA in patients with high BMI. Its result may act as a spark that will drive extensive population-based studies that more precisely delineate the relationship between BMI and the degree of IFTA on different levels.

DNMT3a negatively regulates PTEN to activate the PI3K/AKT pathway to aggravate renal fibrosis

BackgroundRenal fibrosis has become one of the major diseases threatening global public health and harming human life and health. PTEN methylation plays an important role in fibrotic diseases of many organs. However, the relationship between PTEN methylation and renal fibrosis is still elusive. MethodsIn the present study, we established a unilateral ureteral obstruction (UUO) mouse model in vivo and a transforming growth factor β1 (TGF-β1)-stimulated renal tubular epithelial cell (HK−2) model in vitro. The degree of renal interstitial fibrosis was detected by haematoxylin-eosin (HE) staining and Masson's trichrome staining. Western blot (WB), qRT–PCR, immunohistochemistry (IHC) and methylation-specific PCR (MSP) analyses were used to determine the mechanism by which PTEN methylation regulates renal fibrosis. The α-SMA fibrosis marker was detected by immunofluorescence (IF). Additionally, the relationship of PTEN and DNMT3a in UUO was determined by ChIP-qRT–PCR. ResultsOur results showed that the promoter region of PTEN was methylated in UUO. Compared to the sham group, the expression of PTEN was significantly reduced in the UUO group. However, the demethylation reagent significantly inhibited epithelial-mesenchymal transition (EMT), which showed increased expression of E-cadherin and decreased expression of α-SMA and fibronectin. Moreover, treatment of HK-2 cells with 5-aza-dc reversed the activation of the TGF-β1-induced PI3K/AKT signalling pathway, which inhibited renal fibrosis. WB analysis demonstrated that TGF-β1 inhibited the PTEN protein expression level and DNMT3a knockdown reversed the inhibitory effect of TGF-β1 on PTEN expression. Furthermore, ChIP-qRT–PCR showed that DNMT3a interacted with PTEN. Finally, we found that DNMT3a negatively regulated PTEN to activate the PI3K/AKT signalling pathway and aggravate renal fibrosis in vitro and in vivo. ConclusionIn summary, these results indicated that renal fibrosis is related to the downregulation of PTEN. Additionally, DNMT3a negatively regulates PTEN to activate the PI3K/AKT signalling pathway and induce EMT in renal tubular epithelial cells, thereby aggravating renal fibrosis.

Urinary sediment CCL5 messenger RNA as a potential prognostic biomarker of diabetic nephropathy

ABSTRACTBackgroundUrinary sediment messenger RNAs (mRNAs) have been shown as novel biomarkers of kidney disease. We aimed to identify targeted urinary mRNAs in diabetic nephropathy (DN) based on bioinformatics analysis and clinical validation.MethodsMicroarray studies of DN were searched in the GEO database and Nephroseq platform. Gene modules negatively correlated with estimated glomerular filtration rate (eGFR) were identified by informatics methods. Hub genes were screened within the selected modules. In validation cohorts, a quantitative polymerase chain reaction assay was used to compare the expression levels of candidate mRNAs. Patients with renal biopsy–confirmed DN were then followed up for a median time of 21 months. End-stage renal disease (ESRD) was defined as the primary endpoint. Multivariate Cox proportional hazards regression was developed to evaluate the prognostic values of candidate mRNAs.ResultsBioinformatics analysis revealed four chemokines (CCL5, CXCL1, CXLC6 and CXCL12) as candidate mRNAs negatively correlated with eGFR, of which CCL5 and CXCL1 mRNA levels were upregulated in the urinary sediment of patients with DN. In addition, urinary sediment mRNA of CXCL1 was negatively correlated with eGFR (r = −0.2275, P = 0.0301) and CCL5 level was negatively correlated with eGFR (r = −0.4388, P < 0.0001) and positively correlated with urinary albumin:creatinine ratio (r = 0.2693, P = 0.0098); also, CCL5 and CXCL1 were upregulated in patients with severe renal interstitial fibrosis. Urinary sediment CCL5 mRNA was an independent predictor of ESRD [hazard ratio 1.350 (95% confidence interval 1.045–1.745)].ConclusionsUrinary sediment CCL5 and CXCL1 mRNAs were upregulated in DN patients and associated with a decline in renal function and degree of renal interstitial fibrosis. Urinary sediment CCL5 mRNA could be used as a potential prognostic biomarker of DN.

Application of Diffusion Tensor Imaging in Obstructive Nephropathy

Background: Obstructive nephropathy is a common clinical disease. Objectives: To explore the value of diffusion tensor imaging (DTI) in obstructive nephropathy. Materials and Methods: Forty healthy Sprague-Dawley (SD) rats were examined in this study. Thirty-two animals underwent complete obstruction of the left ureter, while eight animals underwent a sham surgery. Magnetic resonance imaging (MRI) was performed before surgery and within different intervals after surgery. Eight rats from the experimental group and two rats from the sham group were used in each interval. Following MRI, the animals were sacrificed and sent for medical examinations. The scanning sequences included positioning, transverse T2-weighted (T2W), coronal, and coronal DTI sequences. Image postprocessing was performed after DTI to measure DTI parameters, including apparent diffusion coefficient (ADC) and fractional anisotropy (FA), and to reconstruct DTI fiber traces. One-way analysis of variance was used to compare the parameters between the cortex and medulla and between different intervals. Results: The fiber tracing showed that the obstructed renal fiber bundles were sparse and disordered. The ADC and FA values of the renal cortex, extrarenal medulla, and inner medulla decreased with prolonged hydrops and were negatively correlated with the expression of alpha-smooth muscle actin (α-SMA) and the renal tubulointerstitial lesion grade (r &lt; 0, P &lt; 0.001). Comparison of the cortex, extrarenal medulla, and inner medulla showed the following trends for the ADC and FA values: cortex &gt; extrarenal medulla &gt; inner medulla and cortex &lt; extrarenal medulla &lt; inner medulla, respectively. Conclusions: DTI in obstructive nephropathy not only can reflect the degree of renal interstitial fibrosis and accurately indicate the renal function, but also can provide information regarding renal blood perfusion, water metabolism, and ultrastructural changes.

A Novel Urinary Proteomics Classifier for Non-Invasive Evaluation of Interstitial Fibrosis and Tubular Atrophy in Chronic Kidney Disease.

Non-invasive urinary peptide biomarkers are able to detect and predict chronic kidney disease (CKD). Moreover, specific urinary peptides enable discrimination of different CKD etiologies and offer an interesting alternative to invasive kidney biopsy, which cannot always be performed. The aim of this study was to define a urinary peptide classifier using mass spectrometry technology to predict the degree of renal interstitial fibrosis and tubular atrophy (IFTA) in CKD patients. The urinary peptide profiles of 435 patients enrolled in this study were analyzed using capillary electrophoresis coupled with mass spectrometry (CE-MS). Urine samples were collected on the day of the diagnostic kidney biopsy. The proteomics data were divided into a training (n = 200) and a test (n = 235) cohort. The fibrosis group was defined as IFTA ≥ 15% and no fibrosis as IFTA < 10%. Statistical comparison of the mass spectrometry data enabled identification of 29 urinary peptides with differential occurrence in samples with and without fibrosis. Several collagen fragments and peptide fragments of fetuin-A and others were combined into a peptidomic classifier. The classifier separated fibrosis from non-fibrosis patients in an independent test set (n = 186) with area under the curve (AUC) of 0.84 (95% CI: 0.779 to 0.889). A significant correlation of IFTA and FPP_BH29 scores could be observed Rho = 0.5, p < 0.0001. We identified a peptidomic classifier for renal fibrosis containing 29 peptide fragments corresponding to 13 different proteins. Urinary proteomics analysis can serve as a non-invasive tool to evaluate the degree of renal fibrosis, in contrast to kidney biopsy, which allows repeated measurements during the disease course.

A novel biomarker of chronic allograft dysfunction in renal transplant recipients (serum calreticulin and CD47)

BackgroundChronic allograft dysfunction (CAD) is considered the leading cause of late allograft loss. The cluster of differentiation 47 (CD47) and calreticulin (CRT) are involved in many and diverse cellular processes. The present study was designed to study the role of the pro-phagocytic CRT and anti-phagocytic CD47 signals in patients with renal transplantation in relation to graft function.Thirty renal transplantation recipients (RTR) for more than 6 months [15 with stable renal function and 15 with chronic allograft dysfunction (CAD)] and 15 healthy controls were enrolled in the study. Quantification of CRT, CD47, and high-sensitivity C-reactive protein (hsCRP) levels in serum was done using standardized enzyme-linked immunosorbent assay (ELISA) kits. Measurement of renal function and urinary alkaline phosphatase (U.ALP) was done. Renal interstitial fibrosis (IF) was graded in renal biopsies of CAD.ResultsSerum CRT and urinary ALP levels were statistically significant higher (P < 0.001) while serum CD47 level was statistically significant lower (P < 0.001) in patients with CAD than patients with stable graft function and controls. There was statistically insignificant difference between controls and patients with stable graft function. Serum CRT and serum CD47 levels were positively correlated with each other and with worsening renal and tubular function, serum hsCRP in RTR and with degree of renal IF in patients with CAD (P < 0.05).ConclusionsThe activation and dysregulation of CRT and CD47 could play a role in the development of CAD and could be a potential biomarker for renal allograft dysfunction.

Increased macrophage activation marker soluble CD163 is associated with graft dysfunction and metabolic derangements in renal transplant recipients

BackgroundRenal allograft is vulnerable to numerous insults and is associated with metabolic derangements. Macrophages are regulators of inflammation and play a role in obesity, lipid metabolism and insulin resistance (IR). The present study was designed to assess macrophage activation, reflected by serum soluble CD163 (sCD163), in renal transplant recipients (RTR) and its relation to chronic allograft dysfunction (CAD) and metabolic derangements. MethodsFifty recipients of renal transplantation (RT) [22 with stable renal function and 28 with CAD] and 20 age- and sex-matched healthy controls were enrolled in the study. Serum sCD163 and high sensitivity C-reactive protein (hsCRP) were measured using enzyme-linked immunosorbent assay. Anthropometric measurements, renal function, lipid profile and homeostatic model assessment of IR (HOMA-IR) were estimated. Renal interstitial fibrosis (IF) was graded in renal biopsies of CAD. ResultsRTR mean age was 38.84 ± 9.28 years and 83% of them were males. Post-transplant dyslipidemia, diabetes and IR (HOMA-IR >2) were present in 42%, 24% and 86% of RTR respectively. Serum sCD163 levels were significantly higher in RTR with stable renal function and CAD than in healthy controls (814.41 ± 59.62 ng/ml and 1021.21 ± 120.82 ng/ml vs. 602.90 ± 114.98 ng/ml respectively) and in RTR with CAD than in patients with stable renal function (p < 0.001). Serum sCD163 levels were positively correlated with body mass index, waist-to-hip ratio, worsening renal function, dyslipidemia, HOMA-IR and serum hsCRP in RTR and with the degree of renal IF in RTR with CAD (p < 0.05). ROC curve showed that serum sCD163 was superior to serum hsCRP in detecting CAD after RT (AUC = 0.972 vs. 0.753 respectively, p = 0.001). ConclusionMacrophage activation, reflected by increased circulating sCD163, may play a role in the development of CAD and metabolic derangements after RT. Serum sCD163 could be a potential biomarker for renal allograft dysfunction.

ADAM10 mediates ectopic proximal tubule development and renal fibrosis through Notch signalling.

Disturbed intrauterine development increases the risk of renal disease. Various studies have reported that Notch signalling plays a significant role in kidney development and kidney diseases. A disintegrin and metalloproteinase domain 10 (ADAM10), an upstream protease of the Notch pathway, is also reportedly involved in renal fibrosis. However, how ADAM10 interacts with the Notch pathway and causes renal fibrosis is not fully understood. In this study, using a prenatal chlorpyrifos (CPF) exposure mouse model, we investigated the role of the ADAM10/Notch axis in kidney development and fibrosis. We found that prenatal CPF‐exposure mice presented overexpression of Adam10, Notch1 and Notch2, and led to premature depletion of Six2+ nephron progenitors and ectopic formation of proximal tubules (PTs) in the embryonic kidney. These abnormal phenotypic changes persisted in mature kidneys due to the continuous activation of ADAM10/Notch and showed aggravated renal fibrosis in adults. Finally, both ADAM10 and NOTCH2 expression were positively correlated with the degree of renal interstitial fibrosis in IgA nephropathy patients, and increased ADAM10 expression was negatively correlated with decreased kidney function evaluated by serum creatinine, cystatin C, and estimated glomerular filtration rate. Regression analysis also indicated that ADAM10 expression was an independent risk factor for fibrosis in IgAN. © 2020 The Authors. The Journal of Pathology published by John Wiley & Sons, Ltd. on behalf of The Pathological Society of Great Britain and Ireland.

Niao Du Kang Mixture Increases the Expression of mir-129-5p to Relieve Renal Fibrosis.

Objective To investigate the efficacy of Niao Du Kang (NDK) mixture in renal fibrosis of rats and to explore the mechanism underlying the effect of NDK on renal fibrosis. Methods Unilateral ureteral obstruction (UUO) was used to replicate a rat renal interstitial fibrosis model. The drug-administered groups were given 20 ml/kg (NDK-H), 10 ml/kg (NDK-M), and 5 ml/kg (NDK-L) NDK mixture once a day for 21 days beginning 48 hours after surgery. The 24-hour urine protein and serum creatinine (CR) levels in the sham group rats, UUO rats, and NDK mixture-treated rats were measured after the last administration. The pathological changes of rat kidney tissue were observed by HE staining. The degree of fibrosis was observed by Masson's staining and scored. The expression levels of TGF-β, α-SMA mRNA, and mir-129-5p in kidney were detected by qRT-PCR. HK-2 cells were treated with 5 ng/ml TGF-β to induce HK-2 cell fibrosis. The expression levels of TGF-β, α-SMA mRNA, and mir-129-5p in HK-2 cells were detected by qRT-PCR. TargetScan predicted the target gene of mir-129-5p, HK-2 cells were transfected with mir-129-5p mimic, and an overexpressed mir-129-5p HK-2 cell model was constructed. qRT-PCR was used to detect the expression of PDPK1 mRNA. Western blot was used to detect the expression of PDPK1, AKT, and p-AKT in HK-2 cells induced by TGF-β and in UUO rats. Results NDK mixture significantly reduced the 24-hour urine protein and CR levels of UUO rats. HE staining showed that the NDK mixture group exhibited a significantly reduced degree of renal interstitial fibrosis. NDK mixture also reduced the expression of TGF-β and α-SMA, and the middle-dose group showed a better therapeutic effect. In vitro studies showed that NDK mixture-containing serum increased the expression of mir-129-5p to reduce renal fibrosis. In addition, NDK mixture increased the expression of mir-129-5p in vivo. Further studies indicated that mir-129-5p could target PDPKl to reduce its expression. The NDK-containing serum group also exhibited reduced expression of PDPK1. Conclusion NDK mixture can significantly improve renal function and improve renal fibrosis in UUO model rats. Furthermore, NDK mixture can inhibit the expression of PDPK1 by upregulating the expression of mir-129-5p and then inhibiting the PI3K/AKT pathway to improve renal fibrosis.

Protein Phosphatase 2A Inhibiting β-Catenin Phosphorylation Contributes Critically to the Anti-renal Interstitial Fibrotic Effect of Norcantharidin.

Norcantharidin (NCTD) is a potential anti-renal interstitial fibrotic drug. However, the underlying molecular mechanism of how NCTD works remains unclear. In this study, using both in vivo and in vitro models, we report that the level of β-catenin is positively correlated to the degree of renal interstitial fibrosis (RIF). Protein phosphatase 2A (PP2A) binds to β-catenin and suppresses its phosphorylation, thereby increasing the total β-catenin expression. Additionally, NCTD dramatically elevates the level of phosphorylated β-catenin and decreases total β-catenin expression in a dose-dependent manner, consequently leading to the reduction of RIF. Mechanistically, PP2A-mediated suppression of β-catenin phosphorylation is an essential target for the anti-renal interstitial fibrotic effect of NCTD. Therefore, we report a potential theoretical basis for clinical application of NCTD in treating RIF.

Dihydromyricetin promotes autophagy and attenuates renal interstitial fibrosis by regulating miR-155-5p/PTEN signaling in diabetic nephropathy

Diabetic nephropathy (DN) is the most common complication of diabetes and is prone to kidney failure. Dihydromyricetin (DHM) has been reported to have a variety of pharmacological activities. This study aims to explore the effect of DHM on DN and the underlying molecular mechanism. An in vivo DN rat model was established. The degree of renal interstitial fibrosis (RIF) was detected by hematoxylin-eosin (HE) staining, Masson’s trichrome staining, and immunohistochemistry (IHC). In vitro, NRK-52E cells were divided into four groups: normal glucose (NG), high glucose (HG), HG+DHM, and HG+rapamycin (autophagy inhibitor). The levels of autophagy- and fibrosis-related proteins were analyzed by western blotting. The expression of miR-155-5p and phosphatase and tensin homolog deleted on chromosome ten (PTEN) and their relationship were assessed by quantitative reverse transcription (qRT)-PCR and dual luciferase reporter gene assay. Our results showed that RIF was increased in DN rat model and in HG-induced NRK-52E cells. DHM treatment attenuated the increased RIF and also increased autophagy. MiR-155-5p expression was increased, while PTEN expression was decreased in DN rat and cell model, and DHM reversed both effects. Dual luciferase assay showed that PTEN was the target gene of miR-155-5p. DHM inhibited HG-induced fibrosis and promoted autophagy by inhibiting miR-155-5p expression in NRK-52E cells. In addition, DHM promoted autophagy by inhibiting the PI3K/AKT/mTOR signaling pathway. In conclusion, DHM promotes autophagy and attenuates RIF by regulating the miR-155-5p/PTEN signaling and PI3K/AKT/mTOR signaling pathway in DN.

Identification of CD2, CCL5 and CCR5 as potential therapeutic target genes for renal interstitial fibrosis

We aimed to explore potential gene biomarkers of renal interstitial fibrosis (RIF) due to a lack of effective and non-invasive methods for diagnosis. Three data sets (GSE22459, GSE76882 and GSE57731) including 350 samples were acquired from Gene Expression Omnibus (GEO) database. We used bioconductor limma package to perform background adjustment. Cluster analysis was conducted by 'edgeR' package to identify the differentially expressed genes (DEGs). We generated heat maps with using heatmap package in R software. Function annotation of genes was performed by Gene Ontology (GO) enrichment analysis. STRING (Search Tool for the Retrieval of Interacting Genes) database was employed to construct the protein-protein interaction (PPI) network and the results were visualized by Cytoscape 3.6.1. At last, we applied Graphpad Prism 7.0. to explore the correlation between three hub genes and pathological degrees of RIF. By applying the "edgeR" package in R, we detected 116 DEGs with three data sets. These genes were enriched in 19 GO biological process categories. Three main hub genes (CD2, CCL5 and CCR5) were identified after construction of PPI network. In Pearson correlation coefficient, CD2, CCL5 and CCR5 was found to hold higher expression patterns in RIF samples based on independent data set GSE57731. Besides, their gene expression levels were found significantly positive correlation with the degree of RIF (CD2: P<0.05, r=0.29; CCL5: P<0.05, r=0.31; CCR5: P<0.05, r=0.38). CD2, CCL5 and CCR5 might serve as potential early biomarkers of RIF. The mechanism between these genes and RIF remains to be further studied.

Transplantation of Amniotic Fluid-Derived Stem Cells Preconditioned with Glial Cell Line-Derived Neurotrophic Factor Gene Alleviates Renal Fibrosis

Amniotic fluid-derived stem cells (AFSCs), which exhibit both embryonic and mesenchymal stem cell characteristics, have been shown to mitigate the degree of renal interstitial fibrosis. The aim of the present study was to determine whether transplantation of glial cell line-derived neurotrophic factor (GDNF)–modified AFSCs is more useful than transplantation of unmodified AFSCs for the treatment of renal interstitial fibrosis. Mice were randomly assigned to a sham-operation group (sham), a unilateral ureteral obstruction (UUO)-saline solution group (UUO), an AFSC transplantation group (AFSC) and a GDNF-modified AFSC transplantation group (GDNF-AFSC) and sacrificed at days 3 and 7 post-surgery (six in each group). We showed that GDNF-AFSCs noticeably suppressed oxidative stress and inflammation; additionally, GDNF-AFSCs positively regulated peritubular capillaries (PTCs), vascular endothelial growth factor (VEGF), hypoxia inducible factor-1α (HIF-1α), and transforming growth factor-β1 (TGF-β1) protein levels. Transmission electron microscopy (TEM) revealed that mitochondrial injury induced by the UUO model was significantly ameliorated after the mice were treated with GDNF-AFSCs. Therefore, we determined that GDNF gene promotes the abilities of AFSCs to inhibit inflammatory and oxidative stress effects, repair renal microvessels, relieve tissue hypoxia and mitochondrial damage, and, ultimately, alleviate renal interstitial fibrosis.

Virtual Touch Tissue Quantification for Assessing Renal Pathology in Idiopathic Nephrotic Syndrome

The aim of this study was to evaluate Virtual Touch tissue quantification in assessing renal interstitial fibrosis in patients with idiopathic nephrotic syndrome. Ninety patients with idiopathic nephrotic syndrome were assigned to mild, moderate and severe groups depending on the degree of renal interstitial fibrosis on histopathologic examination of renal biopsy specimens. Thirty healthy patients were also selected as the control group. Virtual Touch tissue quantification was performed to measure the shear wave velocity of the renal parenchyma. There was no statistically significant difference in shear wave velocity between the mild and control groups (p > 0.05); however, the moderate and severe groups did significantly differ compared with the control (p < 0.001). The area under the receiver operating characteristic curve value for the shear wave velocity of renal interstitial fibrosis in the moderate group versus the control and mild groups together was 0.869 (95% confidence interval: 0.791–0.947) and that in the severe group versus the control, mild and moderate groups together was 0.954 (95% confidence interval: 0.917–0.998). The corresponding best cutoff points were 2.41 and 2.77 m/s, with sensitivities of 91.7% and 86.8%, specificities of 78.0% and 92.0%, negative predictive values 0.907 and 0.907, positive predictive values 0.800 and 0.971 and Youden index values of 0.697 and 0.788, respectively. Virtual Touch tissue quantification may non-invasively and quantitatively estimate the degree of renal interstitial fibrosis in patients with idiopathic nephrotic syndrome as a baseline for monitoring progression and treatment response.

FGF23 promotes renal interstitial fibrosis by activating β-catenin.

To investigate the role and mechanism of fibroblast growth factor 23 (FGF23) in renal interstitial fibrosis. Rat renal tubular epithelial cell line (NRK-52E) was selected for in vitro experiments. Effect of FGF23 on extracellular matrix was observed. High expression of FGF23 was induced by injecting the plasmid into the caudal vein. The model of unilateral ureteral obstruction (UUO) was established for in vivo experiments. FGF23 increased the expression of extracellular matrix proteins FN, α-SMA and Type 1 collagen of NRK-52E induced by TGFβ1, while FGF23 increased the expression of p-β-catenin 675. In UUO model mice, fibrosis in the FGF23 high expression group increased significantly compared to that of the control group. Meanwhile, β-catenin signal was activated. FGF23 can promote the deposition of extracellular matrix of NRK-52E induced by TGFβ1 in vitro. It aggravated the degree of renal interstitial fibrosis in UUO model, which is related to the activation of β-catenin signaling pathway.

Connective tissue growth factor regulates fibrosis-associated renal lymphangiogenesis

Lymphangiogenesis is correlated with the degree of renal interstitial fibrosis. Pro-fibrotic transforming growth factorβ induces VEGF-C production, the main driver of lymphangiogenesis. Connective tissue growth factor (CTGF) is an important determinant of fibrotic tissue remodeling, but its possible involvement in lymphangiogenesis has not been explored. We found prominent lymphangiogenesis during tubulointerstitial fibrosis to be associated with increased expression of CTGF and VEGF-C in human obstructed nephropathy as well as in diabetic kidney disease. Using CTGF knockout mice, we investigated the involvement of CTGF in development of fibrosis and associated lymphangiogenesis in obstructive nephropathy. The increase of lymphatic vessels and VEGF-C in obstructed kidneys was significantly reduced in CTGF knockout compared to wild-type mice. Also in mouse kidneys subjected to ischemia-reperfusion injury, CTGF knockdown was associated with reduced lymphangiogenesis. Invitro, CTGF induced VEGF-C production in HK-2 cells, while CTGF siRNA suppressed transforming growth factor β1-induced VEGF-C upregulation. Furthermore, surface plasmon resonance analysis showed that CTGF and VEGF-C directly interact. Interestingly, VEGF-C-induced capillary-like tube formation by human lymphatic endothelial cells was suppressed by full-length CTGF but not by naturally occurring proteolytic CTGF fragments. Thus, CTGF is significantly involved in fibrosis-associated renal lymphangiogenesis through regulation of, and direct interaction with, VEGF-C.

Lefty1 alleviates renal tubulointerstitial injury in mice with unilateral ureteral obstruction.

Lefty is a member of the transforming growth factor (TGF) β superfamily, which is implicated in left‑right patterning during embryogenesis. Previous studies revealed that lefty attenuates the epithelial‑mesenchymal transition in tubular epithelial cells. In the present study, the protective effect of lefty1 on renal interstitial injury was further assessed. Mice with a unilateral ureteral obstruction (UUO) were sacrificed on days 3, 5 and 7 following surgery, and the association between the expression of lefty1 and the degree of interstitial fibrosis was investigated. Subsequently, mice with a UUO were administered recombinant lefty1 (300 µg/kg body weight) or vehicle (0.9% saline solution; 100 µl) through tail‑vein injection every other day for 6 days. The effects of lefty1 were assessed by measuring the degree of tubulointerstitial fibrosis, tubular injury and atrophy, and also by monitoring the expression levels of α‑smooth muscle actin (α‑SMA), TGF‑β1, phosphorylated (p)‑Smad2/3, kidney injury molecular‑1 and endogenous lefty1. The expression of lefty1 in the kidney decreased in a time‑dependent manner in mice with a UUO, which was inversely correlated with the degree of renal interstitial fibrosis. Furthermore, compared with vehicle treatment, lefty1 attenuated renal interstitial fibrosis. Ureteral ligation induced increased expression levels of α‑SMA, TGF‑β1 and p‑Smad2/3. However, these effects were reduced following treatment with lefty1. The UUO also induced tubular injury and atrophy, whereas lefty1 treatment exerted a marked suppressive effect on tubular injury. In addition, exogenous lefty1 administered to mice restored the endogenous expression levels of lefty1. The present study demonstrated that lefty1 attenuated renal interstitial injury by inhibiting the Smad‑dependent TGF‑β1 signaling pathway. Lefty1 may therefore by a putative therapeutic agent in the treatment of renal injury.

Effect of erythropoietin on the expression of dynamin-related protein-1 in rat renal interstitial fibrosis

This study aimed to observe the expression of dynamin-related protein-1 (Drp-1) in the renal interstitium in a rat model of renal interstitial fibrosis induced by unilateral ureteral obstruction (UUO). In addition, the renoprotective effect of erythropoietin in this model was investigated. A total of 81 rats were randomly assigned to sham surgery, UUO model and treatment groups. Following surgery, the rats in the treatment group were subcutaneously administered erythropoietin at a dose of 3,000 IU/kg once a week until the time of sacrifice. Rats in the sham surgery and UUO model groups were administered an identical volume of normal saline. In each group, nine rats were chosen randomly for sacrifice on days 7, 14 and 21 after surgery for histological examination of renal tissue. Renal tissue specimens were examined by hematoxylin and eosin and Masson's trichrome staining. Immunohistochemical analysis was performed to determine the expression of Drp-1 in the renal interstitium. Renal function damage, as evaluated by the measurement of serum creatinine (Cr) and blood urea nitrogen (BUN) levels, was less severe in the treatment group compared with that in the model group at day 21 (P<0.01). Compared with the UUO model group, the renal interstitial injury score and fibrotic area of the treatment group were decreased markedly at the three time points (P<0.05). The expression level of Drp-1 in the treatment group was decreased markedly at the three time points compared with that in the model group (P<0.05). In conclusion, the expression of Drp-1 is increased in rat renal interstitial fibrosis, and erythropoietin may alleviate the degree of renal interstitial fibrosis by downregulating the expression of Drp-1.