MCP-1 and EGF renal expression and urine excretion in human congenital obstructive nephropathy

Psoralen Alleviates Renal Fibrosis by Attenuating Inflammasome-Dependent NLRP3 Activation and Epithelial-Mesenchymal Transition in a Mouse Unilateral Ureteral Obstruction Model

The role of psoralen (PS), a major active component extracted from Psoralea corylifolia L. seed, in renal fibrosis is still unclear. Thus, the objective of this study was to evaluate the effects of PS on the development and progression of renal fibrosis induced by unilateral ureteral obstruction (UUO) in a mouse model. Mice were divided into four groups: PS (20 mg/kg, i.g., n = 5), PS + sham (n = 5), UUO (n = 10), and PS + UUO (n = 10). PS was intragastrically administered 24 h before UUO and continued afterwards for 7 days. All mice were killed 7 days post UUO. Severe tubular atrophy, tubular injury, and tubulointerstitial fibrosis (TIF) were significantly developed in UUO mice. A higher expression of transforming growth factor-β1 (TGF-β1) was accompanied by elevated levels of α-smooth muscle actin (α-SMA) and phosphorylated Smad2/3 (pSmad2/3) at 7 days post UUO. However, PS treatment reduced tubular injury, interstitial fibrosis, and the expression levels of TGF-β1, α-SMA, and pSmad2/3. Furthermore, the levels of macrophages (represented by F4/80 positive cells) and the inflammasome, reflected by inflammasome markers such as nucleotide-binding and oligomerization domain-like receptors protein 3 (NLRP3) and cleaved caspase1 (cCASP-1), were significantly decreased by PS treatment. These results suggest that PS merits further exploration as a therapeutic agent in the management of chronic kidney disease (CKD).

Diagnostic and prognostic biomarkers for tubulointerstitial fibrosis

Renal fibrosis is the final common pathophysiological pathway in chronic kidney disease (CKD) regardless of the underlying cause of kidney injury. Tubulointerstitial fibrosis (TIF) is considered to be the key pathological predictor of CKD progression. Currently, the gold-standard tool to identify TIF is kidney biopsy, an invasive method that carries risks. Non-invasive diagnostics rely on an estimation of glomerular filtration rate and albuminuria to assess kidney function, but these fail to diagnose early CKD accurately or to predict progressive decline in kidney function. In this review, we summarize the current and emerging molecular biomarkers that have been studied in various clinical settings and in animal models of kidney disease and that are correlated with the degree of TIF. We examine the potential of these biomarkers to diagnose TIF non-invasively and to predict disease progression. We also examine the potential of new technologies and non-invasive diagnostic approaches in assessing TIF. Limitations of current and potential biomarkers are discussed and knowledge gaps identified.

Urinary epidermal growth factor and monocyte chemotactic protein-1 as biomarkers of renal injury in patients with obstructed nephropathy

OBJECTIVE

To evaluate the role of urinary Monocyte Chemotactic Protein-1 (MCP1) and urinary epidermal growth factor (EGF) in diagnosing of upper urinary tract obstruction (UUTO).

PATIENT AND METHODS

Over a period of 6 months (January 2022 to June 2022) this prospective case control comparative study was conducted on 120 participants, 60 of them with UUTO and 60 healthy controls. A morning urine sample of all participants was tested for EGF and MCP-1. after taking a detailed history taking and laboratory and radiological evaluation.

RESULTS

Urinary MCP-1(uMCP-1) was significantly (p-value = 0.000) increased in UUTO group showing a mean ± SD of 518.10 ± 51.19 ng/L compared to a mean ± SD of 143.32 ± 58.03 ng/L in the controls, whereas a significantly (p-value = 0.000) decrease of urinary EGF (uEGF) was observed in patients with UUTO compared to control group. A significant difference of uEGF level and uEGF/uMCP1 ratio was observed between mild compared to moderate/severe UUTO.

CONCLUSIONS

Utilization of the urinary biomarker MCP1, EGF and uEGF/uMCP1 ratio in patients with UUTO can adequately be used as a simple, efficacious and noninvasive way in diagnosis of UUTO.

Role of urinary Neutrophil Gelatinase-Associated Lipocalin (NGAL), Monocyte Chemoattractant Protein-1(MCP-1), and Interleukin-6(IL-6) as biomarkers in pediatric patients with hydronephrosis

OBJECTIVES

The decision to surgically intervene in a hydronephrotic kidney in children is based on many debatable guidelines, some requiring repeated ultrasounds or renal scans. Urinary proteins have the potential to reflect renal disorders and hence can be the alternatives to such scans. Here, we aim to assess the role of urinary Neutrophil Gelatinase-Associated Lipocalin, Monocyte Chemoattractant Protein-1, and Interleukin-6 (IL-6) in such patients.

METHODS

Seventeen children had obstructive hydronephrosis requiring pyeloplasty (UPJO), while seven were kept on conservative management in view of non-obstructive dilation (NOD). Urine samples were measured for the three urinary proteins at the time of presentation and following pyeloplasty using commercially available ELISA kits.

RESULTS

The levels of all three urinary proteins were significantly higher in patients with UPJO children compared to the NOD group. Cut-off values to differentiate obstructive from non-obstructive hydronephrosis were obtained. A significant fall in the post-operative value of urinary IL-6 was also observed.

CONCLUSION

This study highlights the potentiality of urinary proteins as biomarkers in identifying children with hydronephrosis and picking out the ones with obstructive hydronephrosis who will require pyeloplasty. The drop in levels after pyeloplasty can be employed to evaluate the effectiveness of pyeloplasty when sent serially.

Comparing accuracy of urinary biomarkers in differentiation of ureteropelvic junction obstruction from nonobstructive dilatation in children

Multiple urinary biomarkers have been reported in differentiation of nonobstructive dilatation (NOD) from ureteropelvic junction obstruction (UPJO). In this meta-analysis, we compared the accuracy of common urinary biomarkers applicable to UPJO. A systematic literature review of electronic databases was conducted for: (UPJO) OR (NOD) AND (urinary biomarkers) AND (children) for articles published in the last decade. PRISMA guidelines were used to exclude duplicate and erroneous articles. Meta-analysis involved risk of bias analysis, heterogeneity assessment, and comparison of sensitivity/specificity by forest plot analysis using MetaXL 5.3. Among the 264 articles analyzed, 19 articles met the inclusion criteria and reported the following: neutrophil gelatinase-associated lipocalin (NGAL), monocyte chemotactic protein-1 (MCP1), carbohydrate antigen 19-9 (CA 19-9), kidney injury molecule (KIM1), epidermal growth factor (EGF), and interferon gamma induced protein-10 (IP10). There was substantial heterogeneity among articles. There was wide variation in applied cut-offs among studies. Overall sensitivity was highest at 87% for CA 19-9 while overall specificity was highest at 76% for NGAL. Overall accuracy was highest at 78% for CA 19-9 followed by 77% for NGAL and 75% for KIM1. In this meta-analysis, the overall accuracy was highest for CA 19-9 followed by NGAL and KIM1. The small number of studies for CA 19-9 and considerable heterogeneity for all should be considered while interpreting these findings. Based on the current meta-analysis, we support a panel of biomarkers combining NGAL, KIM, and CA 19-9 for the best diagnostic accuracy of UPJO in children.

A systematic review of underlying genetic factors associated with ureteropelvic junction obstruction in stenotic human tissue

OBJECTIVE

Genetic factors are implicated in the development of ureteropelvic junction obstruction (UPJO). The aims of this study were: 1) condense and examine the existing data in studies containing information regarding differential gene expression in tissues from patients with UPJO and 2) investigate associations between genetic markers and their related pathways.

MATERIALS AND METHODS

A systematic review of studies published between January 2000 and September 2021 was conducted using the following databases: Ovid/Medline, PubMed, Wiley Cochrane Central Register of Controlled Trials, Web of Science, and Scopus. Of 249 studies, 10 were included in the final analysis. The search was performed using the terms "ureteropelvic junction obstruction", "genetic", "gene", and "gene expression". Literature pertaining to differential gene expression in UPJO patients as compared to healthy controls was identified. Studies containing gene expression and quantification of molecular data carried out directly on stenotic tissue samples were selected for analysis. Gene network connections and functional analyses were then determined using MetaScape software.

RESULTS

From the ten studies identified for analysis, fifteen genes were noted as differentially expressed. In UPJO patients, nine genes were upregulated (ET1, ACTA2, MCP-1, TGFB1, NFKB1, IL-6, HIF1A, S100A1, SYP) and six were downregulated (ADM, NOS2, EGF, PDGFRA, UCHL1, NGFR). These genes were principally involved in HIF-1 signaling pathway, blood vessel development, positive regulation of signaling receptor activity, and Ras signaling pathway.

CONCLUSIONS

A potential link exists between genes related to hypoxia, excessive fibrous tissue formation, and inflammation in the development of UPJO, and these connections merit more detailed, tissue level investigations in UPJO patients. The outcomes of this systematic review may lay the groundwork for the development of future targeted therapies and novel biomarker detection for treatments, early detection, and possible prediction and prevention of development of UPJO.

Investigation into the effect and mechanism of dapagliflozin against renal interstitial fibrosis based on transcriptome and network pharmacology

BACKGROUND

Renal interstitial fibrosis (RIF) is the final pathway for chronic kidney diseases (CKD) to end-stage renal disease (ESRD). Dapagliflozin, a selective inhibitor of the sodium glucose co-transporter 2, reduced the risk of renal events in non-diabetic CKD patients in the DAPA-CKD trial. However, the effect and mechanism of dapagliflozin on RIF are not very clear. Currently, we evaluate the effects of dapagliflozin on RIF and systematically explore its mechanism.

METHODS AND RESULTS

Firstly, unilateral ureteral obstruction (UUO) mouse model was established to evaluate effects of dapagliflozin on RIF, and results demonstrated dapagliflozin improved renal function and RIF of UUO mice independent of blood glucose control. Subsequently, transcriptome analysis was performed to explore the potential mechanism of dapagliflozin against RIF, which exhibited the therapeutic effect of dapagliflozin on RIF may be achieved through multiple pathways regulation. Then we verified the potential mechanisms with molecular biology methods, and found that dapagliflozin treatment significantly alleviated inflammation, apoptosis, oxidative stress and mitochondrial injury in kidneys of UUO mice. Furthermore, network pharmacology analysis was used to investigate the potential targets of dapagliflozin against RIF. Moreover, we also applied molecular docking and molecular dynamics simulation to predict the specific binding sites and binding capacity of dapagliflozin and hub target.

CONCLUSIONS

Dapagliflozin had therapeutic effect on RIF independent of blood glucose control, and the protective effects probably mediated by multiple pathways and targets regulation.

Early detection of ureteropelvic junction obstruction in neonates with prenatal diagnosis of renal pelvis dilatation using 1H NMR urinary metabolomics

Renal pelvis dilatation (RPD) is diagnosed in utero on prenatal ultrasonography (US) and can resolve spontaneously. However, isolated RPD can also reflect ureteropelvic junction obstruction (UPJO), which requires surgical treatment to prevent progressive renal deterioration. The diagnosis of UPJO can only be confirmed after birth with repeat US and renal isotope studies. ¹H Nuclear Magnetic Resonance spectroscopy (NMR) was performed on urine of newborns with prenatally diagnosed unilateral RPD and healthy controls to identify specific urinary biomarkers for UPJO. The original combination of EigenMS normalization and sparse partial-least-squares discriminant analysis improved selectivity and sensitivity. In total, 140 urine samples from newborns were processed and 100 metabolites were identified. Correlation network identified discriminant metabolites in lower concentrations in UPJO patients. Two main metabolic pathways appeared to be impaired in patients with UPJO i.e. amino acid and betaine metabolism. In this prospective study, metabolic profiling of urine samples by NMR clearly distinguishes patients who required surgery for UPJO from patients with transient dilatations and controls. This study will pave the way for the use of metabolomics for the diagnosis of prenatal hydronephrosis in clinical routine.

Hypercalciuria switches Ca2+ signaling in proximal tubular cells, induces oxidative damage to promote calcium nephrolithiasis

Proximal tubule (PT) transports most of the renal Ca2+, which was usually described as paracellular (passive). We found a regulated Ca2+ entry pathway in PT cells via the apical transient receptor potential canonical 3 (TRPC3) channel, which initiates transcellular Ca2+ transport. Although TRPC3 knockout (-/-) mice were mildly hypercalciuric and displayed luminal calcium phosphate (CaP) crystals at Loop of Henle (LOH), no CaP + calcium oxalate (CaOx) mixed urine crystals were spotted, which are mostly found in calcium nephrolithiasis (CaNL). Thus, we used oral calcium gluconate (CaG; 2%) to raise the PT luminal [Ca2+]o further in TRPC3 -/- mice for developing such mixed stones to understand the mechanistic role of PT-Ca2+ signaling in CaNL. Expectedly, CaG-treated mice urine samples presented with numerous mixed crystals with remains of PT cells, which were pronounced in TRPC3 -/- mice, indicating PT cell damage. Notably, PT cells from CaG-treated groups switched their mode of Ca2+ entry from receptor-operated to store-operated pathway with a sustained rise in intracellular [Ca2+] ([Ca2+]i), indicating the stagnation in PT Ca2+ transport. Moreover, those PT cells from CaG-treated groups demonstrated an upregulation of calcification, inflammation, fibrotic, oxidative stress, and apoptotic genes; effects of which were more robust in TRPC3 ablated condition. Furthermore, kidneys from CaG-treated groups exhibited fibrosis, tubular injury and calcifications with significant reactive oxygen species generation in the urine, thus, indicating in vivo CaNL. Taken together, excess PT luminal Ca2+ due to escalation of hypercalciuria in TRPC3 ablated mice induced surplus CaP crystal formation and caused stagnation of PT [Ca2+]i, invoking PT cell injury, hence mixed stone formation.

The use of biomarkers in the diagnosis and treatment of obstruction of the upper urinary tract in children

Antenatal hydronephrosis, dilatation of the upper urinary tract (UUTD), is a common finding on prenatal ultrasound. One of the most common causes is ureteropelvic junction (UPJ) obstruction. Although such prenatally diagnosed UUTD resolves spontaneously in most newborns, further examination of these children is advocated to prevent possible irreversible kidney damage, and ultrasound is mainly used for this. If the dilatation persists or becomes symptomatic, it is necessary to proceed to other relatively demanding and invasive diagnostic examinations for these small patients, where the question of the right timing of indications for possible surgical solutions is still unclear. For this reason, various biomarkers have been investigated in a number of clinical trials as potential mini-invasive diagnostic tools for determining when upper urinary tract dilatation in such children poses a threat to the developing kidneys and they should be operated on, and vice versa, when to proceed conservatively. The aim of this article is to review the findings on and current issues with the use of biomarkers in the diagnosis and treatment of UPJ obstruction in children.

Urinary biomarkers can identify the need for pyeloplasty in presence of supranormal differential renal function in antenatally diagnosed unilateral hydronephrosis

INTRODUCTION

Decision for surgery can be challenging in children with AH (Antenatal Hydronephrosis) especially in the setting of supranormal differential renal function (SnDRF).

OBJECTIVE

Aim of this study is to investigate whether IP-10 (interferon gamma-induced protein 10), MCP-1 (monocyte chemotactic protein-1), NGAL (neutrophil gelatinase-associated lipocalin), CA 19-9 (carbohydrate antigen 19-9), and KIM-1 (kidney injury molecule-1) can identify the need for pyeloplasty in presence of SnDRF in antenatally diagnosed unilateral hydronephrosis.

STUDY DESIGN

A prospectively collected urinary biomarker database was used for the study. There was a total of 53 patients in the AH group. Nineteen children with no history of AH and a normal urinary ultrasonography were taken as controls. Patients with initial ipsilateral DRF (Differential Renal Function) over 50% were included in the SnDRF group while the remaining were named as non-SnDRF. Patients that didn't undergo surgery were classified as non-obstructive dilation (NOD) in both groups.

RESULTS

Pyeloplasty was performed in 6/20 patients in SnDRF group, and in 19/33 patients in non-SnDRF group. Biomarker levels in the pyeloplasty and NOD groups were not affected by the presence or absence of SnDRF (p = 1.00, for both). Urinary NGAL, and CA 19-9 could determine the need for surgery in SnDRF group with 83% and 100% sensitivity, 86% and 79% specificity, respectively whereas urinary IP-10 and KIM-1 could with 84% and 83% sensitivity, 57% and 71% specificity, respectively. Urinary MCP-1 could differentiate patients who underwent surgery with 83% sensitivity and 50% specificity in SnDRF groups.

CONCLUSION

Our results showed that biomarker levels were not affected whether the kidney has SnDRF. Furthermore, in patients with SnDRF, NGAL and CA 19-9 appear to better estimate requirement for surgical correction before deterioration of renal function.

Prognostic Significance of Urinary Biomarkers in Patients Hospitalized With COVID-19

RATIONALE & OBJECTIVE

Acute kidney injury (AKI) is common in patients with coronavirus disease 2019 (COVID-19) and associated with poor outcomes. Urinary biomarkers have been associated with adverse kidney outcomes in other settings and may provide additional prognostic information in patients with COVID-19. We investigated the association between urinary biomarkers and adverse kidney outcomes among patients hospitalized with COVID-19.

STUDY DESIGN

Prospective cohort study.

SETTING & PARTICIPANTS

Patients hospitalized with COVID-19 (n=153) at 2 academic medical centers between April and June 2020.

EXPOSURE

19 urinary biomarkers of injury, inflammation, and repair.

OUTCOME

Composite of KDIGO (Kidney Disease: Improving Global Outcomes) stage 3 AKI, requirement for dialysis, or death within 60 days of hospital admission. We also compared various kidney biomarker levels in the setting of COVID-19 versus other common AKI settings.

ANALYTICAL APPROACH

Time-varying Cox proportional hazards regression to associate biomarker level with composite outcome.

RESULTS

Out of 153 patients, 24 (15.7%) experienced the primary outcome. Twofold higher levels of neutrophil gelatinase-associated lipocalin (NGAL) (HR, 1.34 [95% CI, 1.14-1.57]), monocyte chemoattractant protein (MCP-1) (HR, 1.42 [95% CI, 1.09-1.84]), and kidney injury molecule 1 (KIM-1) (HR, 2.03 [95% CI, 1.38-2.99]) were associated with highest risk of sustaining primary composite outcome. Higher epidermal growth factor (EGF) levels were associated with a lower risk of the primary outcome (HR, 0.61 [95% CI, 0.47-0.79]). Individual biomarkers provided moderate discrimination and biomarker combinations improved discrimination for the primary outcome. The degree of kidney injury by biomarker level in COVID-19 was comparable to other settings of clinical AKI. There was evidence of subclinical AKI in COVID-19 patients based on elevated injury biomarker level in patients without clinical AKI defined by serum creatinine.

LIMITATIONS

Small sample size with low number of composite outcome events.

CONCLUSIONS

Urinary biomarkers are associated with adverse kidney outcomes in patients hospitalized with COVID-19 and may provide valuable information to monitor kidney disease progression and recovery.

Bioinformatic Analysis Combined With Experimental Validation Reveals Novel Hub Genes and Pathways Associated With Focal Segmental Glomerulosclerosis

Background: Focal segmental glomerulosclerosis (FSGS) is a type of nephrotic syndrome leading to end-stage renal disease, and this study aimed to explore the hub genes and pathways associated with FSGS to identify potential diagnostic and therapeutic targets.

Methods: We downloaded the microarray datasets GSE121233 and GSE129973 from the Gene Expression Omnibus (GEO) database. The datasets comprise 25 FSGS samples and 25 normal samples. The differential expression genes (DEGs) were identified using the R package “limma”. Gene Ontology (GO) function and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were performed using the database for Annotation, Visualization and Integrated Discovery (DAVID) to identify the pathways and functional annotation of the DEGs. The protein–protein interaction (PPI) was constructed based on the Search Tool for the Retrieval of Interacting Genes (STRING) database and visualized using Cytoscape software. The hub genes of the DEGs were then evaluated using the cytoHubba plugin of Cytoscape. The expression of the hub genes was validated by quantitative real-time polymerase chain reaction (qRT-PCR) using the FSGS rat model, and receiver operating characteristic (ROC) curve analysis was performed to validate the accuracy of these hub genes.

Results: A total of 45 DEGs including 18 upregulated and 27 downregulated DEGs, were identified in the two GSE datasets (GSE121233 and GSE129973). Among them, five hub genes with a high degree of connectivity were selected. From the PPI network, of the top five hub genes, FN1 was upregulated, while ALB, EGF, TTR, and KNG1 were downregulated. The qRT-PCR analysis of FSGS rats confirmed that the expression of FN1 was upregulated and that of EGF and TTR was downregulated. The ROC analysis indicated that FN1, EGF, and TTR showed considerable diagnostic efficiency for FSGS.

Conclusion: Three novel FSGS-specific genes were identified through bioinformatic analysis combined with experimental validation, which may promote our understanding of the molecular underpinning of FSGS and provide potential therapeutic targets for the clinical management.

Can urinary biomarkers be used in the outcome assessment of pyeloplasty in children?

Background

To compare the urinary biomarkers—beta 2-microglobulin (β2M), monocyte chemotactic peptide-1 (MCP-1), and transforming growth factor-beta (TGF-β1)—in the outcome assessment of children with pelviureteric junction obstruction (PUJO) undergoing pyeloplasty.

Methods

A prospective study was conducted on children with PUJO who had pyeloplasty in a tertiary care center from July 2016 to March 2018. Urine samples were obtained from freshly voided urine samples before surgery and after 6 months of pyeloplasty. Ratio between the levels of biomarkers and urinary creatinine before and after surgery were compared.

Results

A total of 72 patients had pyeloplasty during this period. The mean levels of standardized urinary β2M, MCP-1 and TGF-β1 before surgery were 3.94 ± 4.06, 96.63 ± 117.68 and 310.65 ± 423.87, respectively, which was significantly higher than the corresponding values in the postoperative period, obtained after 6 months of surgery; postoperative mean values were 3.12 ± 3.95, 25.28 ± 32.06, 109.95 ± 118.72 (P < 0.001), respectively. Using Wilcoxon signed-rank test, fall of MCP-1 and TGF-β1 was more significant compared to β2M.

Conclusion

Urinary biomarkers (β2M, MCP-1 and TGF-β) offer an effective way of outcome assessment of pyeloplasty for PUJO in children, especially MCP-1 and TGF-β1.

Urinary EGF and MCP-1 and risk of CKD after cardiac surgery

BACKGROUNDAssessment of chronic kidney disease (CKD) risk after acute kidney injury (AKI) is based on limited markers primarily reflecting glomerular function. We evaluated markers of cell integrity (EGF) and inflammation (monocyte chemoattractant protein-1, MCP-1) for predicting long-term kidney outcomes after cardiac surgery.METHODSWe measured EGF and MCP-1 in postoperative urine samples from 865 adults who underwent cardiac surgery at 2 sites in Canada and the United States and assessed EGF and MCP-1's associations with the composite outcome of CKD incidence or progression. We used single-cell RNA-Seq (scRNA-Seq) of AKI patient biopsies to perform transcriptomic analysis of programs corregulated with the associated genes.RESULTSOver a median (IQR) follow-up of 5.8 (4.2-7.1) years, 266 (30.8%) patients developed the composite CKD outcome. Postoperatively, higher levels of urinary EGF were protective and higher levels of MCP-1 were associated with the composite CKD outcome (adjusted HR 0.83, 95% CI 0.73-0.95 and 1.10, 95% CI 1.00-1.21, respectively). Intrarenal scRNA-Seq transcriptomes in patients with AKI-defined cell populations revealed concordant changes in EGF and MCP-1 levels and underlying molecular processes associated with loss of EGF expression and gain of CCL2 (encoding MCP-1) expression.CONCLUSIONUrinary EGF and MCP-1 were each independently associated with CKD after cardiac surgery. These markers may serve as noninvasive indicators of tubular damage, supported by tissue transcriptomes, and provide an opportunity for novel interventions in cardiac surgery.TRIAL REGISTRATIONClinicalTrials.gov NCT00774137.FUNDINGThe NIH funded the TRIBE-AKI Consortium and Kidney Precision Medicine Project. Yale O'Brien Kidney Center, American Heart Association, Patterson Trust Fund, Dr. Adam Linton Chair in Kidney Health Analytics, Canadian Institutes of Health Research, ICES, Ontario Ministry of Health and Long-Term Care, Academic Medical Organization of Southwestern Ontario, Schulich School of Medicine & Dentistry, Western University, Lawson Health Research Institute, Chan Zuckerberg Initiative Human Cell Atlas Kidney Seed Network.

CDH12 as a Candidate Gene for Kidney Injury in Posterior Urethral Valve Cases: A Genome-wide Association Study Among Patients with Obstructive Uropathies

Background

Posterior urethral valves (PUVs) and ureteropelvic junction obstruction (UPJO) are congenital obstructive uropathies that may impair kidney development.

Objective

To identify genetic variants associated with kidney injury in patients with obstructive uropathy.

Design, setting, and participants

We included 487 patients born in 1981 or later who underwent pyeloplasty or valve resection before 18 yr of age in the discovery phase, 102 PUV patients in a first replication phase, and 102 in a second replication phase.

Outcome measurements and statistical analysis

Signs of kidney injury were defined as dialysis, nephrectomy, kidney transplantation, estimated glomerular filtration rate (eGFR) <60 ml/min/1.73 m², high blood pressure, antihypertensive medication use, proteinuria, and/or one kidney functioning at <45%. We used χ² tests to calculate p values and odds ratios for >600 000 single-nucleotide polymorphisms (SNPs) in the discovery sample comparing patients with and without signs of kidney injury within 5 yr after surgery. We performed stratified analyses for PUV and UPJO and Kaplan-Meier and Cox regression analyses in the discovery and two replication samples for the associated SNPs, and RNA and protein expression analyses for the associated gene in fetal tissues.

Results and limitations

Despite the small and nonhomogeneous sample, we observed suggestive associations for six SNPs in three loci, of which rs6874819 in the CDH12 gene was the most clear (p = 7.5 × 10^–7). This SNP also seemed to be associated with time to kidney injury in the PUV discovery and replication samples. RNA expression analyses showed clear CDH12 expression in fetal kidneys, which was confirmed by protein immunolocalization.

Conclusions

This study identified CDH12 as a candidate gene for kidney injury in PUV.

Patient summary

We found that variants of the CDH12 gene increase the risk of kidney injury in patients with extra flaps of tissue in the urethra (posterior urethral valves). This is the first report on this gene in this context. Our study provides interesting new information about the pathways involved and important leads for further research for this condition.

Urinary epidermal growth factor as a marker for lupus nephritis: clinical, laboratory, and histopathological study

Background

Lupus nephritis can be seen in up to 60% of all SLE patients with 10–15% of nephritis patients progressing to end-stage renal disease; late diagnosis of lupus nephritis is correlated with a higher frequency of renal insufficiency. The study aim is determination of the value of urinary human epidermal growth factor (urinary EGF) as an early biomarker of lupus nephritis in SLE patients and its relevance to disease activity and renal histopathology.

Results

The study included 58 SLE patients and 30 healthy controls; a significant difference was noticed between SLE and controls in urinary protein, creatinine, protein/creatinine ratio, and urinary EGF. The mean level of urinary EGF was less in classes IV and V renal nephritis than in classes I, II, and III.

There is a significant difference in urinary EGF (33±29, 27±16, P = 0.04) between class II and class III lupus nephritis, with no significant differences in urinary protein, creatinine, protein/creatinine ratio, and SLEDAI. On the other hand, the comparison between classes II and IV showed significant difference not only in urinary EGF (33±29, 11.7±4.9 m, P=0.003), but also in SLEDAI (37.4±8, 70.5±27, P= 0.007), and protein/creatinine ratio (0.98±0.62, 3±1.8, P=0.006).

Conclusion

This study raises the attention to test the sensitivity of urinary EGF in detecting the early and the subsequent changes in renal pathology of SLE patients as an easy, non-invasive, accurate, cheap marker that could help in following up the nephritis progression and adjusting the plan of treatment; also, it can be used to guide the time of biopsy or as an alternative in cases where renal biopsy is contraindicated.

Can serum Neutrophil Gelatinase Associated Lipocalin and Kidney Injury Molecule-1 help in decision making for surgery in antenatally dedected hydronephrosis

INTRODUCTION

Congenital obstructive uropathies are among leading reasons for renal failure in children. Answers to questions such as what the critical threshold of obstruction is or which degree of obstruction disrupts the development of the kidney still remain unclear. Several biomarkers such as Kidney Injury Molecule 1 (KIM-1) and Neutrophil Gelatinase Associated Lipocalin (NGAL) may help clinicians in the clinical evaluation and appropriate planning of the disease.

OBJECTIVE

This study aimed to investigate whether serum and urinary KIM-1 and NGAL levels contribute to conventional methods in decision-making for surgery in the postnatal period of infants with antenatal hydronephrosis.

STUDY DESIGN

34 patients with the diagnosis of antenatal hydronephrosis were evaluated prospectively. Renal pelvis diameters of all patients were above 10 mm in the ultrasonography (USG). Patients underwent diuretic renal scintigraphy after neonatal period. Patients were divided into two groups as surgery or follow-up based on USG and scintigraphy findings. Blood and urine samples were collected at first visits in both groups and again at the 3. Postoperative month in the surgery group. Serum and urinary NGAL and KIM-1 levels were measured by ELISA method. Study data were compared through the Mann-Whitney U and Wilcoxon Signed-Ranks test.

RESULTS

There were 10 patients in the surgery group and 24 patients in the follow-up group. The age and gender did not differ between the groups. The surgery group had significantly higher median serum NGAL values (259.2 ng/mL) than that in the follow-up group (46.8 ng/mL, p = 0.028). The postoperative reduction of the median serum NGAL to 68.1 ng/mL compared to preoperative level was also found to be significant (p = 0.037) in the surgery group. Between the groups and within the surgery group no statistically significant difference was detected in terms of median urinary NGAL, and serum and urine KIM-1 levels.

DISCUSSION

USG and renal scintigraphy are frequently used in determining whether patients with antenatal hydronephrosis need surgical intervention in the postnatal period. Several new biomarkers might help clinicians in decision making for surgery. KIM-1 and NGAL levels can be measured both in urine and serum. To our knowledge, this is the only study where serum NGAL and KIM-1 levels were measured in patients with antenatal diagnosis. Small sample size, lack of long term findings and control group are limitations of our study.

CONCLUSION

Serum NGAL levels of patients with antenatal hydronephrosis may help in decision making on the surgical intervention.

Roles Played by Biomarkers of Kidney Injury in Patients with Upper Urinary Tract Obstruction

Partial or complete obstruction of the urinary tract is a common and challenging urological condition caused by a variety of conditions, including ureteral calculi, ureteral pelvic junction obstruction, ureteral stricture, and malignant ureteral obstruction. The condition, which may develop in patients of any age, induces tubular and interstitial injury followed by inflammatory cell infiltration and interstitial fibrosis, eventually impairing renal function. The serum creatinine level is commonly used to evaluate global renal function but is not sensitive to early changes in the glomerular filtration rate and unilateral renal damage. Biomarkers of acute kidney injury are useful for the early detection and monitoring of kidney injury induced by upper urinary tract obstruction. These markers include levels of neutrophil gelatinase-associated lipocalin (NGAL), monocyte chemotactic protein-1, kidney injury molecule 1, N-acetyl-b-D-glucosaminidase, and vanin-1 in the urine and serum NGAL and cystatin C concentrations. This review summarizes the pathophysiology of kidney injury caused by upper urinary tract obstruction, the roles played by emerging biomarkers of obstructive nephropathy, the mechanisms involved, and the clinical utility and limitations of the biomarkers.

Biomarkers in vesicoureteral reflux: an overview

Aim: This article aimed to review the role of cytokines, chemokines, growth factors and cellular adhesion molecules as biomarkers for vesicoureteral reflux (VUR) and reflux nephropathy (RN). Methods: We reviewed articles from 1979 onward by searching PubMed and Scopus utilizing the combination of words: 'VUR' or 'RN' and each one of the biomarkers. Results: Genetic, inflammatory, fibrogenic, environmental and epigenetic factors responsible for renal scarring need to be better understood. TGF-β, IL-10, IL-6, IL-8 and TNF seem to exert a role in VUR particularly in RN based on the current literature. Serum levels of procalcitonin have been also associated with high-grade VUR and RN. These molecules should be more intensively evaluated as potential biomarkers for renal scarring in VUR. Conclusion: Further studies are necessary to define which molecules will really be of utility in clinical decisions and as therapeutic targets for VUR and RN.

Association between epidermal growth factor (EGF) and EGF receptor gene polymorphisms and end-stage renal disease and acute renal allograft rejection in a Korean population

Purpose

Epidermal growth factor (EGF) has been found to be associated with the development and repair mechanisms of several renal diseases. In this study, we hypothesized that single nucleotide polymorphisms (SNPs) in EGF or its receptor genes might have an association with end-stage renal disease (ESRD) or acute renal allograft rejection (AR) in a Korean population.

Methods

Three-hundred and forty seven recipients of the first renal transplants for ESRD, including 63 AR patients along with 289 healthy adults were included in the study. Five EGF gene SNPs (rs11568835, rs11568943, rs2237051, rs11569017, and rs3756261) and four EGFR gene SNPs (rs1140475, rs2293347, rs1050171, and rs6965469) were analyzed. The genotypes of these SNPs were analyzed using the AxiomTM genome-wide human assay. Statistical analysis was performed using SNPStats and Haploview version 4.2 software. Multiple logistic regression models (codominant, dominant, recessive, and Log-additive) were used to estimate the odds ratio (OR), 95% confidence interval (CI), and P value.

Results

One SNP (rs11569017) in the EGF gene showed significant association with ESRD but not with AR. Another SNP (rs11568835) in the EGF gene showed significant association with susceptibility to AR but not with ESRD. One SNP (rs1050171) in the EGFR gene showed significant association with susceptibility to AR but not with ESRD.

Conclusion

Our findings suggest that SNPs in the EGF and EGFR gene may be associated with the risk of ESRD and AR development in the Korean population.

Biomarkers of Acute and Chronic Kidney Disease

The current unidimensional paradigm of kidney disease detection is incompatible with the complexity and heterogeneity of renal pathology. The diagnosis of kidney disease has largely focused on glomerular filtration, while assessment of kidney tubular health has notably been absent. Following insult, the kidney tubular cells undergo a cascade of cellular responses that result in the production and accumulation of low-molecular-weight proteins in the urine and systemic circulation. Modern advancements in molecular analysis and proteomics have allowed the identification and quantification of these proteins as biomarkers for assessing and characterizing kidney diseases. In this review, we highlight promising biomarkers of kidney tubular health that have strong underpinnings in the pathophysiology of kidney disease. These biomarkers have been applied to various specific clinical settings from the spectrum of acute to chronic kidney diseases, demonstrating the potential to improve patient care.

Urinary biomarkers in pelvic-ureteric junction obstruction: a systematic review

Antenatal hydronephrosis is a common finding detected on prenatal ultrasound. Although hydronephrosis will spontaneously resolve in the majority of newborns, there is a significant amount of cases that will worsen with the risk of a progressive and permanent loss of renal function. There is an increasing concern among experts that the current criteria for evaluation of clinically significant obstructions are limited. Our aim is to provide a systematic review of the available literature on biomarkers of renal injury, potential targets for diagnosis and prognosis of children with hydronephrosis. The main search was conducted in the electronic databases from inception through March 2019 using various combinations of the keywords: pelvic-ureteric [All Fields] AND junction [All Fields] AND obstruction [All Fields] AND “biomarkers” [MeSH Terms] OR “biomarkers” [All Fields] OR “biomarker” [All Fields]. To broaden the research, additional articles were identified through hand-searching review of the references reported in each study previously selected. Histopathological studies, studies with no control group or with participants suffering from concomitant urological diseases and articles published in language other than English were excluded. Data on study design, sample size, average patient age, hydronephrosis definition used, surgical indication, duration and pattern of follow-up, details on biomarker studied, diagnostic test characteristics, area under the curve (AUC) on receiver operating characteristic (ROC) analysis with the best cut-off (BCO) values, sensitivity, specificity and outcomes were all collected. 38 articles analysing 41 biomarkers were selected. The most frequent proteins investigated were neutrophil gelatinase-associated lipocalin (NGAL) (n=9; 23.7%), monocyte chemotactic peptide-1 (MCP1) (n=8; 21.1%), transforming growth factor β1 (TGFβ1) (n=7; 18.4%), epidermal growth factor (EGF) (n=6; 15.8%) and kidney injury molecule 1 (KIM 1) (n=6; 15.8%). Twenty-seven (71.1%) studies evaluated the effect of pyeloplasty on voided urine biomarker concentrations, comparing their values before and after surgery. Twelve (31.6%) studies investigated the correlation between preoperative biomarker concentration and the anterior posterior renal pelvis diameter (DAP) while 20 (52.6%) studies investigated the correlation between preoperative biomarker concentration with the split renal function (SRF) measured on nuclear medicine assessments. ROC curves were used to investigate the performance of urinary biomarkers in the total patient data set in 27 (71.1%) studies. Some biomarkers offer promising results. However, a critic analysis of the published studies demonstrates bias and lack of consistency suggesting that larger multicentre and carefully designed prospective studies are still needed to evaluate the clinical usefulness of urinary biomarkers in the diagnosis and follow-up of children with congenital obstructive hydronephrosis.

Urinary prostaglandin E2 is a biomarker of early adaptive hyperfiltration in solitary functioning kidney

INTRODUCTION

Hyperfiltration is a major contributor to progression of chronic kidney disease (CKD) in diabetes, obesity and in individuals with solitary functioning kidney (SFK). We have proposed hyperfiltration-induced injury as a continuum of overlapping glomerular changes caused by increased biomechanical forces namely, fluid flow shear stress (FFSS) and tensile stress. We have shown that FFSS is elevated in animals with SFK and, it upregulates prostaglandin E₂ (PGE₂), cyclooxygenase-2 and PGE₂ receptor EP2 in cultured podocytes and in uninephrectomized mice. We conceptualized urinary PGE₂ as a biomarker of early effects of hyperfiltration-induced injury preceding microalbuminuria in individuals with SFK. We studied children with SFK to validate our hypothesis.

METHODS

Urine samples from children with SFK and controls were analyzed for PGE₂, albumin (glomerular injury biomarker) and epidermal growth factor (EGF, tubular injury biomarker). Age, gender, and Z-scores for height, weight, BMI, and blood pressure were obtained.

RESULTS

Children with SFK were comparable to controls except for lower BMI Z-scores. The median values were elevated in SFK compared to control for urine PGE₂ [9.1 (n = 57) vs. 5.7 (n = 72), p = 0.009] ng/mgCr and albumin [7.6 (n = 40) vs. 7.0 (n = 41), p = 0.085] μg/mgCr, but not for EGF [20098 (n = 44) vs. 18637 (n = 44), p = 0.746] pg/mgCr. Significant increase in urinary PGE₂ (p = 0.024) and albumin (p = 0.019) but not EGF (p = 0.412) was observed using additional regression modeling. These three urinary analytes were independent of each other.

CONCLUSION

Increased urinary PGE₂ from elevated SNGFR and consequently increased FFSS during early stage of CKD precedes overt microalbuminuria and is a biomarker for early hyperfiltration-induced injury in individuals with SFK.

Value of urinary carbohydrate antigen 19-9 to predict failure of conservative management in children with ureteropelvic junction obstruction

OBJECTIVE

To assess the role of urinary carbohydrate antigen 19-9 (CA19-9) measurement in determining optimal management of ureteropelvic junction obstruction (UPJO) and predicting failure of conservative management.

PATIENTS AND METHODS

Children with UPJO diagnosed between December 2012 and April 2015 were included. Depending on clinical and para-clinical findings, patients were divided into three groups: Group 1 consisted of patients who were considered for non-operative management with improvement of the condition during the course of follow-up. Group 2 were suitable for observation; however due to deterioration of condition pyeloplasty was indicated after a period of observation. Group 3 patients required immediate pyeloplasty. Urinary CA19-9 was measured in all patients at baseline and compared between the study groups.

RESULTS

A total of 112 children (115 affected kidneys) with UPJO and mean age of 18.6 ± 3.3 months were assessed. Group 1, 2, and 3 consisted of 54(48.2%), 24(21.4%), and 34(30.4%) patients, respectively. Mean baseline urinary CA19-9 was 37.83 ± 5.20, 145.45 ± 18.38 and 244.62 ± 41.42 in groups 1, 2 and 3, respectively. Multivariate analysis showed that both CA19-9 and APD are independent predictors of need for surgery in patients on observation. ROC curve analysis revealed that urinary CA19-9 level at cut off value of 52.6 U/mL had sensitivity of 92.0% and specificity of 70.9% in predicting failure of non-operative management.

CONCLUSION

Higher urinary CA19-9 level is associated with failure of non-operative management in patients with UPJO. Such patients may require close follow-up and assessments to prevent irreversible damage to the kidney.

TYPE OF STUDY

Study of Diagnostic Test.

LEVEL OF EVIDENCE

Level II.

Biomarkers of Chronic Renal Tubulointerstitial Injury

Progression of renal parenchyma injury is characterized by increasing interstitial fibrosis and tubular atrophy, irrespective of the cause. Histopathologic assessment of renal tissue obtained by biopsy remains the gold standard for determining the presence and extent of tubulointerstitial scarring. Discovery of robust non-invasive means for capturing a snapshot and for longitudinal monitoring of parenchymal deterioration has been the focus of intense multimodal effort by investigators within the renal community and beyond. Research in this field has included the use of in vitro and in vivo experimental models and has fostered the development and evaluation of tissue and biofluid assays for novel analytes with potential translation to the diagnosis and prognosis of kidney disease. Here, we examine recent advances in the search of "biomarkers" for detection of renal tubulointerstitial scarring and prediction of renal outcome in human renal disease.

Epidermal growth factor and its influencing variables in healthy children and adults

Background & objective

Epidermal growth factor (EGF) stimulates cell proliferation and differentiation after binding to its receptor. Next to its role in magnesium homeostasis, EGF disturbances have been described in oncology, diabetes and autism spectrum disorders. The aim of this study was to determine EGF serum and urine values for both healthy children and adults. Next, we investigated the relation between several variables and urinary and serum EGF concentrations.

Methods

Both healthy adults (n = 50) and children (n = 78) were included. Serum and urinary EGF concentrations were measured with ELISA technology.

Results

Serum EGF was inversely correlated with age (r = —0.873; p<0.001) and positively correlated with serum magnesium (r = 0.597; p<0.001). The urinary EGF was also inversely correlated with age (r = -0.855; p<0.001). In adults and children older than 13 years of age, the urinary EGF significantly differed between sexes (p = 0.001). Urinary EGF was positively correlated with serum magnesium (r = 0.583; p<0.001) and creatinine clearance (r = 0.524; p<0.001) and negatively correlated with the fractional excretion of magnesium (r = 0.248; p = 0.014). In a multivariate model, age and serum magnesium remained independently related to serum EGF while age, serum EGF and serum magnesium remained independently related to urinary EGF.

Conclusions

This study provides valuable insights in urinary and serum EGF patterns in healthy subjects. By systematically correcting EGF for body surface, significant correlations with age, gender and magnesium were observed.

Abnormal Expression of miR-21 in Kidney Tissue of Dogs With X-Linked Hereditary Nephropathy: A Canine Model of Chronic Kidney Disease

MicroRNAs (miRNAs) are a group of small noncoding RNAs that act as regulators of posttranslational gene/protein expression and are known to play a key role in physiological and pathological processes. The objective of our study was to compare expression of miR-21 in renal tissue from dogs affected with chronic kidney disease (CKD) caused by X-linked hereditary nephropathy (XLHN), a disease equivalent to human Alport syndrome, to that from unaffected dogs. Additionally, we sought to characterize changes in relative mRNA expression of various genes associated with miR-21 function. miRNA was isolated from kidney tissue collected from both affected dogs and unaffected, age-matched littermates at defined milestones of disease progression, including end-stage renal disease (ESRD). Additionally, autopsy samples from affected dogs at ESRD and corresponding unaffected dogs were evaluated. Samples were scored based on histological changes, and relative expression of miR-21 and kidney disease-related genes was determined using quantitative real-time polymerase chain reaction. In affected dogs, significant upregulation of kidney miR-21 was first detected at the milestone corresponding with increased serum creatinine. Furthermore, miR-21 expression correlated significantly with urine protein: urine creatinine ratio, serum creatinine concentration, glomerular filtration rate, and histologic lesions (glomerular damage, tubular damage, chronic inflammation, and fibrosis). At end-stage disease, COL1A1, TGFB1 and its receptor, TGFB2, and Serpine1 were upregulated, while PPARA, PPARGC1A, ACADM, SOD1, and EGF were downregulated. In conclusion, miR-21 is abnormally upregulated in the kidneys of dogs with CKD caused by XLHN, which may play an important pathologic role in the progression of disease by dysregulating multiple pathways.

Candidate gene and mechanism investigations in congenital obstructive nephropathy based on bioinformatics analysis

The aim of the present study was to explore the candidate genes, chemicals and mechanisms of congenital obstructive nephropathy (CON). The gene expression profiles of GSE48041, including 24 kidney tissue samples from megabladder (mgb‑/‑) mouse were downloaded from the Gene Expression Omnibus database. Samples were divided into 4 groups: Control, mild, moderate and severe. Differentially expressed genes (DEGs), protein‑protein interaction network, Kyoto Encyclopedia of Genes and Genomes pathways and transcription factor (TF)‑target gene analyses were performed on Set 1 (mild, moderate and severe groups), while Gene Ontology (GO) function enrichment analysis and chemical investigation were performed on Set 2 (severe group). A total of 187 and 139 DEGs were obtained in Set 1 and Set 2, respectively. Chemical carcinogenesis [enriched by genes such as Carbonyl reductase 1 (CBR1)] was one of the most prominent pathways in Set 1. GO analysis for Set 2 revealed that DEGs were mainly assembled in functions such as cellular response to interleukin‑1 and cellular response to tumor necrosis. Furthermore, genes such as Fos Proto‑Oncogene (FOS) were co‑regulated by TFs including RNA polymerase II subunit A (Polr2a) and serum response factor (Srf). Chemical cyclosporine served the most important role in Set 2 by targeting several DEGs in Set 2. DEGs such as CBR1 and FOS, TFs including Polr2a and Srf, and pathways such as chemical carcinogenesis may serve important roles in the process of CON. Interleukin‑1 and tumor necrosis function may be novel targets for CON gene therapy. Furthermore, cyclosporine may be a promising option for future CON therapy.

Urinary epidermal growth factor predicts renal prognosis in antineutrophil cytoplasmic antibody-associated vasculitis

INTRODUCTION

The current study aimed to investigate the association between urinary epidermal growth factor (uEGF) and renal disease severity and outcomes in patients with antineutrophil cytoplasmic antibody-associated vasculitis (AAV).

METHODS

Intrarenal EGFmRNA expression was extracted from transcriptomic data of microdissected tubulointerstitial compartments of kidney biopsies of patients with AAV. uEGF was measured in 173 patients with AAV in active stage and 143 in remission, and normalised to urine creatinine excretion (uEGF/Cr). The association between uEGF/Cr (or EGFmRNA) and clinical-pathological parameters was tested using linear regression analysis. The ability of uEGF/Cr to predict renal outcomes was analysed using Cox's regression analysis.

RESULTS

In patients with AAV, intrarenal EGFmRNA expression was significantly associated with estimated glomerular filtration rate (eGFR)(log2) at time of biopsy (β=0.63, p<0.001). The level of uEGF/Cr was significantly higher in patients in remission than in patients with active disease, both when looking at patients with sequential measurements (2.75±1.03vs 2.08±0.98, p<0.001) and in cross-sectional comparison. uEGF/Cr level was positively associated with eGFR(log2) at time of sampling in both active and remission stage (β=0.60, p<0.001; β=0.74, p<0.001, respectively). Patients with resistant renal disease had significantly lower uEGF/Cr levels than responders (1.65±1.22vs 2.16±1.26, p=0.04). Moreover, after adjusting for other potential predictors, uEGF/Cr was independently associated with composite endpoint of end-stage renal disease or 30% reduction of eGFR (HR 0.61, 95% CI 0.45 to 0.83, p=0.001).

CONCLUSION

Lower uEGF/Cr levels are associated with more severe renal disease, renal resistance to treatment and higher risk of progression to composite outcome in patients with AAV.

Exosomal proteomic analysis reveals changes in the urinary proteome of rats with unilateral ureteral obstruction

Congenital urinary tract obstruction (UTO) is a commonly noted disorder with the potential to cause permanent loss of renal function. Due to the possibility of spontaneous resolution, postnatal management strategies require lengthy and invasive surveillance methods to monitor the status of renal function and severity of obstruction. Here, a quantitative proteome analysis of urinary exosomes from weanling rats with surgically introduced UTO identifies a number of candidate biomarkers with the potential to improve diagnostic and prognostic methods for this disease. Using gel-assisted digestion coupled to liquid chromatography/tandem mass spectrometry (LC–MS/MS), 318 proteins were identified. Relative protein quantitation by spectral counting showed 190 proteins with significant changes in abundance due to either partial or complete obstruction. Numerous proteins identified here have been shown to be similarly altered in abundance in other renal diseases that cause tubule apoptosis and interstitial fibrosis. Extrapolating the role of the proteins showing quantifiable changes in abundance here from other forms of renal disease suggests they have potential for clinical applicability as biomarkers of congenital UTO. Included in the list of identified proteins are markers of apoptosis, oxidative stress, fibrosis, inflammation, and tubular cell damage, which are commonly associated with UTO. This study therefore provides a number of candidate biomarkers that, following validation in children experiencing UTO, have the potential to improve postnatal management of this disease.

Identification of key microRNAs, transcription factors and genes associated with congenital obstructive nephropathy in a mouse model of megabladder

OBJECTIVE

The present study aimed to investigate the molecular mechanism underlying congenital obstructive nephropathy (CON).

METHODS

The microarray dataset GSE70879 was downloaded from the Gene Expression Omnibus, including 3 kidney samples of megabladder mice and 4 control kidneys. Using this dataset, differentially expressed miRNAs (DEMs) were identified between the kidney samples from megabladder mice and controls, followed by identification of the target genes for these DEMs and construction of a DEM and target gene interaction network. Additionally, the target genes were subjected to Gene Ontology and pathway enrichment analyses, and were used for construction of a protein-protein interaction (PPI) network. Finally, regulatory networks were constructed to analyze transcription factors for the key miRNAs.

RESULTS

From 17 DEMs identified between kidney samples of megabladder mice and controls, 3 key miRNAs were screened, including mmu-miR-150-5p, mmu-miR-374b-5p and mmu-miR-126a-5p. The regulatory networks identified vascular endothelial growth factor A (Vegfa) as the common target gene of mmu-miR-150-5p and five transcription factors, including nuclear receptor subfamily 4, group A, member 2 (Nr4a2), Jun dimerisation protein 2 (Jdp2), Kruppel-like factor 6 (Klf6), Neurexophilin-3 (Nxph3) and RNA binding motif protein 17 (Rbm17). The gene encoding phosphatase and tensin homolog (Pten) was found to be co-regulated by mmu-miR-374b-5p and high mobility group protein A1 (Hmga1), whereas the kirsten rat sarcoma viral oncogene (Kras) was identified as a common target gene of mmu-miR-126a-5p and paired box 6 (Pax6).

CONCLUSIONS

In summary, the above-listed key miRNAs, transcription factors and key genes may be involved in the development of CON.

Urinary epidermal growth factor as a prognostic marker for the progression of Alport syndrome in children

BACKGROUND

Alport syndrome is a rare hereditary kidney disease manifested with progressive renal failure. Considerable variation exists in terms of disease progression among patients with Alport syndrome. Identification of patients at high risk of rapid progression remains an unmet need. Urinary epidermal growth factor (uEGF) has been shown to be independently associated with risk of progression to adverse kidney outcome in multiple independent adult chronic kidney disease (CKD) cohorts. In this study, we aim to assess if uEGF is associated with kidney impairment and its prognostic value for children with Alport syndrome.

METHODS

One hundred and seventeen pediatric patients with Alport syndrome and 146 healthy children (3-18 years old) were included in this study. uEGF was measured in duplicates in baseline urine samples using ELISA (R&D) and concentration was normalized by urine creatinine (uEGF/Cr). In patients with longitudinal follow-up data (n = 38), progression was defined as deteriorated kidney function (CKD stage increase) during follow-up period (follow-up length is about 31 months in average). The association of baseline uEGF/Cr level with estimated glomerular filtration rate (eGFR) slope and Alport syndrome patients' progression to a more advanced CKD stage during the follow-up period was used to evaluate the prognostic value of the marker.

RESULTS

We found that uEGF/creatinine (uEGF/Cr) decreases with age in pediatric patients with Alport syndrome with a significantly faster rate than in healthy children of the same age group. uEGF/Cr is significantly correlated with eGFR (r = 0.75, p < 0.001), after adjustment for age. In 38 patients with longitudinal follow-up, we observed a significant correlation between uEGF/Cr and eGFR slope (r = 0.58, p < 0.001). Patients with lower uEGF/Cr level were at increased risk of progression to a higher CKD stage. uEGF/Cr was able to distinguish progressors from non-progressors with an AUC of 0.88, versus 0.77 by eGFR and 0.81 by 24-h urinary protein (24-h UP).

CONCLUSIONS

Our study suggests that uEGF/Cr is a promising biomarker for accelerated kidney function decline in pediatric patients with Alport syndrome. It may help to identify patients at high risk of progression for targeted clinical care and improve the patients' stratification in interventional trials.

The molecular biology of pelvi-ureteric junction obstruction

Over recent years routine ultrasound scanning has identified increasing numbers of neonates as having hydronephrosis and pelvi-ureteric junction obstruction (PUJO). This patient group presents a diagnostic and management challenge for paediatric nephrologists and urologists. In this review we consider the known molecular mechanisms underpinning PUJO and review the potential of utilising this information to develop novel therapeutics and diagnostic biomarkers to improve the care of children with this disorder.

Urinary Biomarkers to Identify Autosomal Dominant Polycystic Kidney Disease Patients With a High Likelihood of Disease Progression

Introduction

The variable disease course of autosomal dominant polycystic kidney disease (ADPKD) makes it important to develop biomarkers that can predict disease progression, from a patient perspective and to select patients for renoprotective treatment. We therefore investigated whether easy-to-measure urinary biomarkers are associated with disease progression and have additional value over that of conventional risk markers.

Methods

At baseline, inflammatory, glomerular, and tubular damage markers were measured in 24-hour urine collections (albumin, IgG, kidney injury molecule−1 (KIM-1), N-acetyl-β-d-glucosaminidase (NAG), β2 microglobulin (β2MG), heart-type fatty acid binding protein (HFABP), macrophage migration inhibitory factor (MIF), neutrophil gelatinase-associated lipocalin (NGAL), and monocyte chemotactic protein−1 (MCP-1). Disease progression was expressed as annual change in estimated glomerular filtration rate (eGFR, Chronic Kidney Disease EPIdemiology equation), measured glomerular filtation rate (mGFR, using ¹²⁵I-iothalamate), or height-adjusted total kidney volume (htTKV). Multivariable linear regression was used to assess associations of these markers independent of conventional risk markers.

Results

A total of 104 ADPKD patients were included (40 ± 11 years, 39% female, eGFR 77 ± 30, mGFR 79 ± 30 ml/min per 1.73 m² and htTKV 852 [510−1244] ml/m). In particular, β2MG and MCP-1 were associated with annual change in eGFR, and remained associated after adjustment for conventional risk markers (standardized β = −0.35, P = 0.001, and standardized β = −0.29, P = 0.009, respectively). Adding β2MG and MCP-1 to a model containing conventional risk markers that explained annual change in eGFR significantly increased the performance of the model (final R² = 0.152 vs. 0.292, P = 0.001). Essentially similar results were obtained when only patients with an eGFR ≥ 60 ml/min per 1.73 m² were selected, or when change in mGFR was studied. Associations with change in htTKV were less strong.

Conclusion

Urinary β2MG and MCP-1 excretion were both associated with GFR decline in ADPKD, and had added value beyond that of conventional risk markers. These markers therefore have the potential to serve as predictive tools for clinical practice.

Urinary excretion of EGF and MCP-1 in children with vesicoureteral reflux

Purpose

The aim of this study was to investigate the urinary concentration of epidermal growth factor (EGF) and monocyte chemotactic protein-1 (MCP-1) as reflux nephropathy (RN) biomarkers before and after endoscopic treatment of moderate to severe vesico-ureteral reflux (VUR).

Materials and methods

A prospective study was carried out on 72 children with moderate to severe VUR. All patients underwent endoscopic treatment using Macroplastique® or Deflux®. Vesico-ureteral reflux resolution was tested by post-operative voiding cystourethrography after 3 months and 2 years. Follow-up urinary samples were collected at that time. Control samples were taken from healthy children with no clinical evidence of renal and bladder disease and no history of UTI.

Results

In VUR patients, pre-operative urinary EGF levels had a down-regulation when compared to controls. Following successful VUR repair, urinary EGF levels of VUR children progressively increased only at long term follow-up but without returning to normal levels. Urinary MCP-1 levels were highly expressed in pre-operative samples and decreased markedly during early post-operative measurements. Urinary MCP-1 levels did not further decreased in late post-operative follow-up. In fact, these levels remained significantly higher when compared to controls.

Conclusions

Urinary levels of EGF and MCP-1 may become useful markers for monitoring the response to surgical treatment in VUR patients. Although endoscopic VUR treatment is effective in reducing the inflammatory response, the persistence of significant abnormal levels of inflammatory cytokines (such as urinary MCP-1) at long term follow-up suggests that surgery alone may not completely treat the chronic renal inflammation evidenced in these children.

Mast Cells and MCPT4 Chymase Promote Renal Impairment after Partial Ureteral Obstruction

Obstructive nephropathy constitutes a major cause of pediatric renal progressive disease. The mechanisms leading to disease progression are still poorly understood. Kidney fibrotic lesions are reproduced using a model of partial unilateral ureteral obstruction (pUUO) in newborn mice. Based on data showing significant mast cell (MC) infiltration in patients, we investigated the role of MC and murine MCPT4, a MC-released chymase, in pUUO using MC- (W^sh/sh), MCPT4-deficient (Mcpt4^−/−), and wild-type (WT) mice. Measurement of kidney length and volume by magnetic resonance imaging (MRI) as well as postmortem kidney weight revealed hypotrophy of operated right kidneys (RKs) and compensatory hypertrophy of left kidneys. Differences between kidneys were major for WT, minimal for W^sh/sh, and intermediate for Mcpt4^−/− mice. Fibrosis development was focal and increased only in WT-obstructed kidneys. No differences were noticed for local inflammatory responses, but serum CCL2 was significantly higher in WT versus Mcpt4^−/− and W^sh/sh mice. Alpha-smooth muscle actin (αSMA) expression, a marker of epithelial–mesenchymal transition (EMT), was high in WT, minimal for W^sh/sh, and intermediate for Mcpt4^−/− RK. Supernatants of activated MC induced αSMA in co-culture experiments with proximal tubular epithelial cells. Our results support a role of MC in EMT and parenchyma lesions after pUUO involving, at least partly, MCPT4 chymase. They confirm the importance of morphologic impairment evaluation by MRI in pUUO.

The role of urinary KIM-1, NGAL, CA19-9 and β2-microglobulin in the assessment of ureteropelvic junction obstruction in adults

PURPOSE

The objective of this study is to evaluate the diagnostic properties of urinary biomarkers in adults with ureteropelvic junction obstruction: KIM-1, NGAL, CA19-9, and β2-microglobulin. We also assessed urinary biomarker concentrations following pyeloplasty.

MATERIAL AND METHODS

We prospectively studied adults from December 2013 to February 2015. We included 47 patients with a mean age of 38.6 ± 12.7 years. Each patient provided four samples of voided urine for biomarker measurement, one at pre-operative consultation and the others at 1, 3, and 6 months of post-operative follow-up. The control group consisted of 40 healthy individuals with no hydronephrosis on ultrasound evaluation.

RESULTS

KIM-1 had an area under the curve of 0.79 (95% CI 0.70-0.89), NGAL 0.71 (95% CI 0.61-0.83), CA19-9 0.70 (95% CI 0.60-0.81), and β2-microgloblin 0.61 (95% CI 0.50-0.73). KIM-1 was the most sensitive marker with a cut-off of 170.4 pg/mg creatinine (sensitivity 91.4%, specificity 59.1%), whereas CA19-9 was the most specific with a cut-off of 51.3 U/mg creatinine (sensitivity 48.9%, specificity 88.0%). Urinary concentrations of biomarkers decreased after pyeloplasty.

CONCLUSIONS

The evaluation of urinary biomarkers is useful in adults undergoing pyeloplasty. KIM-1, NGAL, and CA19-9 were elevated and significantly decreased after surgery.

Urinary biomarkers for renal tract malformations

INTRODUCTION

Renal tract malformations (RTMs) are congenital anomalies of the kidneys and urinary tract, which are the major cause of end-stage renal disease in children. Using immunoassay-based approaches (ELISA, western blot), individual urinary proteins including transforming growth factor β, tumor necrosis factor and monocyte attractant proteins 1 were found to be associated to RTMs. However, only mass spectrometry (MS) based methods leading to the identification of panels of protein-based markers composed of fragments of the extracellular matrix allowed the prediction of progression of RTMs and its complications. Areas covered: In this review, we summarized relevant studies identified in "Pubmed" using the keywords "urinary biomarkers" and "proteomics" and "renal tract malformations" or "hydronephrosis" or "ureteropelvic junction obstruction" or "posterior urethral valves" or "vesicoureteral reflux". These publications represent studies on potential protein-based biomarkers, either individually or combined in panels, of RTMs in human and animal models. Expert commentary: Successful use in the clinic of these protein-based biomarkers will need to involve larger scale studies to reach sufficient power. Improved performance will potentially come from combining immunoassay- and MS-based markers.

Tissue transcriptome-driven identification of epidermal growth factor as a chronic kidney disease biomarker

Chronic kidney disease (CKD) affects 8 to 16% people worldwide, with an increasing incidence and prevalence of end-stage kidney disease (ESKD). The effective management of CKD is confounded by the inability to identify patients at high risk of progression while in early stages of CKD. To address this challenge, a renal biopsy transcriptome-driven approach was applied to develop noninvasive prognostic biomarkers for CKD progression. Expression of intrarenal transcripts was correlated with the baseline estimated glomerular filtration rate (eGFR) in 261 patients. Proteins encoded by eGFR-associated transcripts were tested in urine for association with renal tissue injury and baseline eGFR. The ability to predict CKD progression, defined as the composite of ESKD or 40% reduction of baseline eGFR, was then determined in three independent CKD cohorts. A panel of intrarenal transcripts, including epidermal growth factor (EGF), a tubule-specific protein critical for cell differentiation and regeneration, predicted eGFR. The amount of EGF protein in urine (uEGF) showed significant correlation (P < 0.001) with intrarenal EGF mRNA, interstitial fibrosis/tubular atrophy, eGFR, and rate of eGFR loss. Prediction of the composite renal end point by age, gender, eGFR, and albuminuria was significantly (P < 0.001) improved by addition of uEGF, with an increase of the C-statistic from 0.75 to 0.87. Outcome predictions were replicated in two independent CKD cohorts. Our approach identified uEGF as an independent risk predictor of CKD progression. Addition of uEGF to standard clinical parameters improved the prediction of disease events in diverse CKD populations with a wide spectrum of causes and stages.

Role of Urinary and Serum Carbohydrate Antigen 19-9 as a Biomarker in Diagnosis of Adult Giant Hydronephrosis

INTRODUCTION

The most common cause of adult Giant Hydronephrosis (GH) is congenital Uretero-Pelvic Junction (UPJ) obstruction. Conventional imaging modalities, like Intravenous Urography (IVU) and Computed Tomography Urography (CTU) and radionuclide renal scan can be fallacious. Serum carbohydrate antigen 19-9 (CA19-9) is a useful tumour marker for gastrointestinal and pancreatic cancer. Only a few studies and case reports have shown raised serum levels due to benign hydronephrosis and GH.

AIM

To investigate the prognostic role of urine and serum CA19-9 in the diagnosis and follow-up of adult GH due to UPJ obstruction.

MATERIALS AND METHODS

The present hospital based observational study was conducted on 24 adult patients (Group 1) with unilateral GH due to UPJ obstruction. Twenty four healthy adults were included as control (Group 2). Serum and voided urine samples were collected to evaluate Carbohydrate Antigen (CA) 19-9 in each group. During surgery, urine from the affected pelvis was collected to determine CA19-9 level. Patients were followed up after surgery at 3 and 9 months with serum and voided urine samples for CA19-9 level.

RESULTS

Preoperative Serum and voided urine CA19-9 were significantly greater in Group1 than in controls, which significantly correlated inversely with preoperative percentage renal function and glomerular filtration rate. Postoperative improvement in renal function significantly correlated inversely with serum and voided urine CA19-9 at 3 and 9 months.

CONCLUSION

Voided urine CA19-9 can be a non-invasive clinical marker in adult GH due to UPJ obstruction. The clinical implications of these data for diagnosis and follow-up of these patients are significant. Our findings suggest, significant decrease in urinary Ca19-9 level during follow-up is predictive of excellent surgical outcome and resolution of renal damage.

Prognostic factors and biomarkers of congenital obstructive nephropathy

Congenital obstructive nephropathy (CON) is the leading cause of chronic kidney disease (CKD) in children. Anomalies of the urinary tract are often associated with abnormal nephrogenesis, which is compounded by obstructive injury and by maternal risk factors associated with low birth weight. Currently available fetal and postnatal imaging and analytes of amniotic fluid, urine, or blood lack predictive value. For ureteropelvic junction obstruction, biomarkers are needed for optimal timing of pyeloplasty; for posterior urethral valves, biomarkers of long-term prognosis and CKD are needed. The initial nephron number may be a major determinant of progression of CKD, and most patients with CON who progress to renal failure reach this point in adulthood, presumably compounded by episodes of acute kidney injury. Biomarkers of tubular injury may be of particular value in predicting the need for surgical intervention or in tracking progression of CKD, and must be adjusted for patient age. Discovery of new biomarkers may depend on "unbiased" proteomics, whereby patterns of urinary peptide fragments from patients with CON are analyzed in comparison to controls. Most promising are the analysis of urinary exosomes (restricting biomarkers to relevant tubular cells) and quantitative magnetic resonance imaging techniques allowing precise determination of nephron number and tubular mass. The greatest need is for large prospective multicenter studies with centralized biomarker sample repositories to follow patients with CON from fetal life through adulthood.

Tubulointerstitial Fibrosis of Living Donor Kidneys Associates with Urinary Monocyte Chemoattractant Protein 1

BACKGROUND

Non-invasive biomarkers that detect occult pathology in patients with normal glomerular filtration rate (GFR) and normal urine albumin excretion may help identify patients at risk for chronic kidney diseases.

METHODS

Two promising biomarkers of interstitial fibrosis, urinary monocyte chemoattractant protein 1 (MCP-1) and collagen IV, were assayed among 634 living kidney donors from 2005 to 2011, who had both a frozen pre-donation spot urine sample and a core needle biopsy of their donated kidney at transplantation ('time zero biopsy'). The association of urine MCP-1 and collagen IV with kidney function (GFR and urine albumin excretion), kidney volume on computed tomographic imaging and histological findings was assessed.

RESULTS

The mean ± SD age was 45 ± 12 years, 24-hour urine albumin was 4 ± 7 mg and measured GFR (mGFR) was 102 ± 18 ml/min/1.73 m2. The median (25th-75th percentile) urine level of MCP-1 was 146 (54-258) pg/ml and of collagen IV was 2.0 (1.0-3.5) µg/l. Higher urine MCP-1 associated with higher 24-hour urine albumin excretion; higher urine collagen IV associated with male gender. On kidney biopsy, any interstitial fibrosis was present in 22% and fibrosis >5% in 4% of donors. The mean MCP-1/Cr ratio was 1.49 pg/mg for 0% fibrosis, 1.80 pg/mg for 1-5% fibrosis, 2.33 pg/mg for 6-10% fibrosis and 4.33 pg/mg for >10% fibrosis. After adjustment for age, sex, mGFR and 24-hour urine albumin, higher urine MCP-1 but not collagen IV associated with interstitial fibrosis and tubular atrophy.

CONCLUSION

Urine MCP-1 may detect early tubulointerstitial fibrosis in adults with normal kidney function.

The roles of serum and urinary carbohydrate antigen 19-9 in the management of patients with antenatal hydronephrosis

INTRODUCTION

Serum carbohydrate antigen (CA) 19-9 has been clinically applied as a valuable tumor marker for pancreatic and gastrointestinal carcinoma. CA 19-9 is expressed in normal excretory epithelium tissues. Increased CA 19-9 has also been observed in uroepithelial tumors as well as in nonmalignant conditions including hydronephrosis secondary to ureteral stones.

OBJECTIVE

The purpose of this article is to evaluate the role of urinary CA 19-9 as a non-invasive biomarker in the postnatal differentiation of obstructive and non-obstructive hydronephrosis in patients with unilateral antenatal hydronephrosis.

STUDY DESIGN

Infants with isolated renal pelvic dilatation, defined as the presence of anteroposterior pelvic diameter (APPD) equal to or greater than 7 mm based on antenatal ultrasound after 28 weeks' gestation, underwent systematic investigation for uropathies and were prospectively followed up. The pyeloplasty group consisted of 17 patients with ureteropelvic junction (UPJ) obstruction who had undergone pyeloplasty. The non-obstructive dilatation (NOD) group consisted of 17 patients with non-obstructive hydronephrosis, and the control group consisted of 21 healthy children. Commercial enzyme-linked immunosorbent assay (ELISA) kits were used to measure the urinary and serum CA 19-9 levels. In both hydronephrosis groups (pyeloplasty and non-obstructive dilatation), the correlations between urinary and serum CA 19-9 levels with the anteroposterior pelvic diameter measured at the third trimester and the postnatal initial evaluation and differential renal function were investigated.

RESULTS

The initial median urinary CA 19-9 levels were significantly greater in children who underwent pyeloplasty than in both the non-obstructive hydronephrosis (143 ± 38 vs. 68 ± 23, respectively; p = 0.007) and the healthy control groups (143 ± 38 vs. 13 ± 3, respectively; p = 0.001) (Figure). Three months after surgery, the urinary CA 19-9 levels had decreased significantly according to the preoperative levels in the pyeloplasty group (143 ± 38 vs. 55 ± 16, p = 0.039). In both the pyeloplasty and NOD groups, there was a correlation of urinary CA 19-9 levels with differential renal function and a correlation of serum CA 19-9 levels with the initial anteroposterior pelvic diameter. Receiver operator characteristic (ROC) analysis revealed a better diagnostic profile for the urinary CA 19-9 level than for the serum CA 19-9 level in terms of identifying obstruction in the hydronephrosis groups (areas under the curve = 0.8 and 0.7, respectively). The best cut-off value of for urinary CA 19-9 was 85.5 U/mL with 76% sensitivity, 85% specificity. The negative predictive value was 80%.

DISCUSSION

The results suggest that voided urine CA 19-9 levels seems to be a more useful marker than serum CA 19-9 in obstructive dilatation. An appropriate decrease in urinary CA 19-9 levels after pyeloplasty may be used as a predictor of surgical outcome. In addition, the results have a number of important diagnostic implications that should be further validated in a larger study population.

CONCLUSIONS

Based on these results, we suggest that a high urinary CA 19-9 level is a non-invasive clinically applicable marker for differentiating between obstruction and non-obstructive dilatation.