Interactions between cytokines, congenital anomalies of kidney and urinary tract and chronic kidney disease

Tubular and glomerular biomarkers of renal tissue function in the urine of fetuses with posterior urethral valves

INTRODUCTION

Posterior urethral valve (PUV) is a congenital malformation characterized by a membranous structure located in the prostatic portion of the male posterior urethra that obstructs the urinary flow. Efforts have been made to determine the degree of impairment of fetal kidney function in this condition.

OBJECTIVE

This study aimed to measure the levels of urinary biomarkers of glomerular and tubular functions in fetuses with PUV and to compare with the levels of the same molecules in healthy male premature newborns.

STUDY DESIGN

Urine samples from 43 fetuses with PUVs were collected and compared with urine samples from 40 healthy male newborns of the same gestational age (controls). Tubular and glomerular biomarkers levels were measured in urine samples by MILLIPLEX® assay kits. Levels of the molecules were related to creatinine (Cr) measurements at same urine samples and expressed as pg/mg Cr. Results were analysed with Graphpad Prism version 7.0 and SPSS version 20.0.

RESULTS

Fetuses with PUV showed a significant reduction in urine levels of Epidermal Growth Factor (EGF), Calbindin, Osteoactivin, Molecule Renal Injury 1 (KIM-1 and Factor of trefoil 3 (TFF-3) when compared to controls. On the other hand, urine levels of cystatin C and renin were higher in PUV fetuses. The levels of molecules also differed according to urine osmolality and grade of hydronephrosis.

DISCUSSION

Some urinary excreted molecules may indicate kidney damage in several segments along the nephron, while others may exert important functions. Mechanical and immunological mechanisms related to PUV might significantly modulate the synthesis of cytokines related to glomerular and tubular physiology, leading to alterations in urinary concentrations of those molecules. These biomarkers can be used as future diagnostic and prognostic markers in clinical practice.

CONCLUSION

Early kidney structural and functional impairment influenced the synthesis of glomerular and tubular molecules related to kidney physiological processes in fetuses with PUV.

Hemostasis and oxidative stress in chronic kidney disease in children and adolescents

Chronic kidney disease (CKD) can be defined as the progressive loss of renal function, characterized by decreased glomerular filtration rate (GFR). The etiology of CKD in childhood is mainly associated with congenital anomalies of the kidneys and urinary tract (CAKUT) and to glomerular diseases. The goal of this study was to investigate the hemostasis and oxidative stress in pediatric CKD of different etiologies. 54 CKD children and adolescents and 52 controls were enrolled in this study. The evaluation of hemostasis was carried out by determination of D-Dimer (D-Di) and plasminogen activator inhibitor (PAI-1) plasma levels, while oxidative stress by thiobarbituric acid reactive substances (TBARS) levels, protein carbonyl content, plasma antioxidant capacity (MTT) and ascorbate. The D-Di was increased in CAKUT stage 3 or 4 patients compared to those with glomerular disease. PAI-1 was increased in patients with glomerular disease compared to CAKUT. Carbonyl protein content was higher in the control group compared to glomerular disease stage 3 or 4 patients. Our findings showed that the reduction in GFR is associated with a state of hypercoagulability. The analysis of integrated networks showed an expansion of connections among hemostatic and oxidative stress markers in CKD children and adolescents comparing to controls.

2020 update on the renin-angiotensin-aldosterone system in pediatric kidney disease and its interactions with coronavirus

The last decade was crucial for our understanding of the renin-angiotensin-aldosterone system (RAAS) as a two-axis, counter-regulatory system, divided into the classical axis, formed by angiotensin-converting enzyme (ACE), angiotensin II (Ang II), and the angiotensin type 1 receptor (AT1R), and the alternative axis comprising angiotensin-converting enzyme 2 (ACE2), angiotensin-(1-7) (Ang-(1-7)), and the Mas receptor. Breakthrough discoveries also took place, with other RAAS endopeptides being described, including alamandine and angiotensin A. In this review, we characterize the two RAAS axes and the role of their components in pediatric kidney diseases, including childhood hypertension (HTN), pediatric glomerular diseases, congenital abnormalities of the kidney and urinary tract (CAKUT), and chronic kidney disease (CKD). We also present recent findings on potential interactions between the novel coronavirus, SARS-CoV-2, and components of the RAAS, as well as potential implications of coronavirus disease 2019 (COVID-19) for pediatric kidney diseases.

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.

Transforming Growth Factor-Beta 1 and Endoglin Levels in Congenital Solitary Functioning Kidney

Introduction:

Glomerular hyperfiltration leads to hypertension, microalbuminuria, and impaired renal function in children with congenital solitary functioning kidney (cSFK). The purpose of this study was to investigate the associations between serum transforming growth factor β-1 (TGF) and endoglin levels and hypertension, renal function or microalbuminuria in children with cSFK.

Materials and Methods:

63 patients and 36 controls were included in the study. Serum endoglin and TGF-β1 level was measured using ELISA commercial kits.

Results:

Serum TGF-β1 and endoglin levels were higher in patients than those of controls (P = 0.04 and P < 0.001, respectively). The prevalence of hypertension was found to be 45.6%. There was a positive association between endoglin levels and the presence of masked hypertension (odds ratio: 1.121, P = 0.04). TGF-β1 and endoglin levels were positively associated with microalbuminuria (OR: 1.17, P = 0.04; OR: 1.836, P = 0.01). ROC curve analysis showed that serum endoglin and TGF-β1 levels had predictive value for microalbuminuria (cut-off value: 4.86 ng/mL, sensitivity: 94.7%, specificity: 54.5%, area under the curve ± standard error [AUC ± SE]: 0.888 ± 0.025, P = 0.01 for endoglin; cut-off value 561.24 pg/mL, sensitivity: 89.5%, specificity: 73%, AUC ± SE: 0.995 ± 0.334, P = 0.02 for TGF-β1). There were no significant relationships between glomerular filtration rate and serum TGF-β1 or endoglin levels.

Conclusions:

Endoglin and TGF-β1 may play an important role in the pathophysiology of microalbuminuria in cSFK. Endoglin may have a role in the development of hypertension in children with cSFK.

Serum creatinine levels in cases of posterior urethral valve: 29 years experience of a pediatric urology reference center

OBJECTIVES

The aim of this retrospective study is to describe the importance of serum creatinine levels for the long-term renal outcome in cases of posterior urethral valve.

METHODS

Records of 94 patients who underwent cystoscopic valve ablation were evaluated retrospectively. Demographic variables, radiologic findings, and serum creatinine levels were recorded. Patients were grouped according to the serum creatinine levels in the first month of life. Twenty-four patients' serum creatinine levels were found to be above 1 mg/dL in group 1 and ≤1 mg/dL in 70 patients in group 2.

RESULTS

The initial findings of 74 patients were as follows: pyelonephritis in 24 (32.43%) patients, hydronephrosis in 20 (27.02%), and inability to urinate in 18 (24.32%). Prenatal hydronephrosis was present in 36 cases (38.29%). Of the 92 voiding cystograms, 53.26% had findings that included vesicoureteral reflux. The mean serum creatinine levels of the patients in group 1 increased above 1 mg/dL in the 2nd year, the significant difference between the two groups lasted up to 7 years of age, and no significant difference was observed at the age of 7. The mean serum creatinine levels of the patients in group 2 were observed to increase above 1 mg/dL by the 10th year.

CONCLUSIONS

In patients with posterior urethral valves, nadir creatinine, especially higher than 1 mg/dL, should be considered as high risk for end-stage renal disease. Therefore, clinicians should improve awareness about early detection and treatment of posterior urethral valves, and these patients should be monitored as early as possible for the risk of chronic kidney disease.

The protective arm of the renin-angiotensin system may counteract the intense inflammatory process in fetuses with posterior urethral valves

OBJECTIVE

Posterior urethral valve is the most common lower urinary tract obstruction in male children. A high percentage of patients with posterior urethral valve evolve to end-stage renal disease. Previous studies showed that cytokines, chemokines, and components of the renin-angiotensin system contribute to the renal damage in obstructive uropathies. The authors recently found that urine samples from fetuses with posterior urethral valve have increased levels of inflammatory molecules. The aim of this study was to measure renin-angiotensin system molecules and to investigate their correlation with previously detected inflammatory markers in the same urine samples of fetuses with posterior urethral valve.

METHODS

Urine samples from 24 fetuses with posterior urethral valve were collected and compared to those from 22 healthy male newborns at the same gestational age (controls). Renin-angiotensin system components levels were measured by enzyme-linked immunosorbent assay.

RESULTS

Fetuses with posterior urethral valve presented increased urinary levels of angiotensin (Ang) I, Ang-(1-7) and angiotensin-converting enzyme 2 in comparison with controls. ACE levels were significantly reduced and Ang II levels were similar in fetuses with posterior urethral valve in comparison with controls.

CONCLUSIONS

Increased urinary levels of angiotensin-converting enzyme 2 and of Ang-(1-7) in fetuses with posterior urethral valve could represent a regulatory response to the intense inflammatory process triggered by posterior urethral valve.

Prognostic significance of maternal urinary carbohydrate antigen 19-9 for antenatal diagnosis of posterior urethral valve associated with fetal hydronephrosis

PURPOSE

To evaluate the predictive role of maternal urinary CA 19-9 as a non-invasive marker for diagnosing antenatal posterior urethral valve (PUV).

METHODS

A total of 40 women in the third pregnancy trimester were enrolled. Case group (group A) consisted of 20 women with a diagnosis of antenatal PUV. Twenty women with similar gestational age, fetal sex, normal US, and no history of congenital anomalies were chosen as a control group (group B). Maternal urine samples were collected and urinary CA 19-9 was measured in both groups. The correlations between maternal urinary CA 19-9 and APD (measured during pregnancy and the initial evaluation of the newborn) were assessed. CA 19-9 level in first urine of neonates was also evaluated.

RESULTS

The mean ± SD of maternal urine CA 19-9 was higher in PUV group compared to the control group (131.6 ± 23.8 vs. 13 ± 2.7 U/mL). In addition, there was a significant correlation between maternal urinary CA 19-9 and the APD measured at the third trimester (p < 0.001) and the initial evaluation of fetus after birth according to SFU grading system (p < 0.001). However, no significant difference was found between gestational age and urinary CA 19-9 level (p = 0.34). There was also a significant correlation between the CA 19-9 level in first urine of neonates and CA 19-9 level of maternal urine (p < 0.001).

CONCLUSIONS

This is the first time that maternal urinary CA 19-9 has been applied as a noninvasive and practical diagnostic marker in antenatal PUV.

Posterior urethral valve in fetuses: evidence for the role of inflammatory molecules

BACKGROUND

The aim of this cross-sectional study was to investigate inflammatory biomarkers in urine samples of 24 fetuses with posterior urethral valve (PUV) collected at 22 ± 4 weeks of gestation and to compare the findings with measurements in urine samples of 22 male healthy preterm neonates at 23 ± 4 weeks (control group).

METHODS

Inflammatory biomarkers in urine were measured using a cytometric bead array [interleukin (IL)-2, IL-4, IL-6, IL-10, interferon (IFN)-γ, soluable tumor necrosis factor receptor (TNFR) 1, sTNFR2, monocyte chemoattractant protein-1/chemokine ligand 2 (MCP-1/CCL2), eotaxin/CCL11 and interferon gamma-induced protein/10/C-X-C motif chemokine 10 (IP-10/CXCL10)] and ELISA assays [TNF, IL-8/CXCL8 and transforming growth factor-beta (TGF-β)]. The Mann-Whitney test was used to compare medians. Markers of glomerular (creatinine) and tubular [beta 2 (β₂)-microglobulin, uromodulin, osmolality] functions were correlated with inflammatory biomarkers (Spearman test).

RESULTS

An intense inflammatory profile was identified, with significantly increased concentrations of urinary IL-2, IL-4, IL-6, TNF, sTNFRI, sTNFRII, IFN-γ, MCP-1/CCL2, eotaxin/CCL11 and IL-8/CXCL8 in the PUV group compared to the controls. The same was observed for the anti-inflammatory cytokine IL-10 and for the fibrogenic mediator TGF-β. In the correlation analysis, β₂-microglobulin positively correlated with the presence of MCP-1/CCL2, sTNFRI and eotaxin/CCL11 and negatively correlated with the presence of creatinine.

CONCLUSIONS

This study shows that inflammatory molecules are already increased in fetuses with PUV at the mean gestational age of 22 weeks, suggesting a physiopathological role for inflammation just after the embryological formation of the urethral membrane.

Imaging studies and biomarkers to detect clinically meaningful vesicoureteral reflux

The work-up of a febrile urinary tract infection is generally performed to detect vesicoureteral reflux (VUR) and its possible complications. The imaging modalities most commonly used for this purpose are renal-bladder ultrasound, voiding cystourethrogram and dimercapto-succinic acid scan. These studies each contribute valuable information, but carry individual benefits and limitations that may impact their efficacy. Biochemical markers are not commonly used in pediatric urology to diagnose or differentiate high-risk disease, but this is the emerging frontier, which will hopefully change our approach to VUR in the future. As it becomes more apparent that there is tremendous clinical variation within grades of VUR, the need to distinguish clinically significant from insignificant disease grows. The unfortunate truth about VUR is that recommendations for treatment may be inconsistent. Nuances in clinical decision-making will always exist, but opinions for medical versus surgical intervention should be more standardized, based on risk of injury to the kidney.

Estimation of the relationship between the polymorphisms of selected genes: ACE, AGTR1, TGFβ1 and GNB3 with the occurrence of primary vesicoureteral reflux

PURPOSE

Etiopathogenesis of VUR is composite and not fully understood. Many data indicate the importance of genetic predisposition. The aim of this study was to establish the relationship of selected polymorphisms: 14094 polymorphism of the ACE, polymorphism rs1800469 of TGFβ-1, rs5443 gene polymorphism of the GNB3 and receptor gene polymorphism rs5186 type 1 AGTR1 with the occurrence of the primary vesicoureteral reflux.

MATERIAL

The study included 190 children: 90 with the primary VUR confirmed with the voiding cystourethrogram and excluded secondary VUR and a control group of 100 children without a history of the diseases of the genitourinary tract.

METHODS

The study was planned in the scheme: "tested case versus control." Genomic DNA was isolated from the leukocytes of peripheral blood samples. The results were statistically analyzed in the Statistica 10 using χ ² test and analysis of the variance Anova.

RESULTS

Any of the four studied polymorphisms showed no difference in the distribution of genotypes between patients with primary vesicoureteral reflux and the control group. In patients with VUR and TT genotype polymorphism rs5443 GNB3 gene, the glomerular filtration rate was significantly higher than in patients with genotype CC or CT.

CONCLUSIONS

(1) No relationship was found between the studied polymorphisms (14094 ACE gene, rs1800469 gene TGFβ1, GNB3 gene rs5443, rs5186 AGTR1 gene) and the occurrence of primary vesicoureteral reflux. (2) TT genotype polymorphism rs5443 GNB3 gene may be a protective factor for the improved renal function in patients with primary vesicoureteral reflux in patients with genotype CC or CT.

Guggulsterone Attenuated Lipopolysaccharide-Induced Inflammatory Responses in Mouse Inner Medullary Collecting Duct-3 Cells

Guggulsterone (GS) is a phytosterol that has been used to treat inflammatory diseases such as colitis, obesity, and thrombosis. Although many previous studies have examined activities of GS, the effect of GS on lipopolysaccharide (LPS)-induced inflammatory responses in mouse inner medullary collecting duct-3 (mIMCD-3) cells have not been examined. Therefore, here, we investigated the anti-inflammatory action of GS on mIMCD-3 cells exposed to LPS. LPS treatment on mIMCD-3 cells produced pro-inflammatory molecules such as inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-α) significantly; however, GS treatment significantly inhibited the production of pro-inflammatory molecules. In addition, GS inhibited the degradation of Iκ-Bα and translocation of NF-κB on mIMCD-3 cells. These results suggest that GS could inhibit inflammatory responses in collecting duct cells which could contribute to kidney injury during systemic infection.

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.

Evaluation and management of hydronephrosis in the neonate

PURPOSE OF REVIEW

The prenatal detection of congenital anomalies of the kidney and urinary tract (CAKUT) has permitted the early management of these conditions. The aim of this review is to provide an overview of the management of neonates with antenatal hydronephrosis (ANH).

RECENT FINDINGS

In spite of the continuous advances in the understanding of the genetic basis, clinical course, and outcomes of CAKUT, there are still many controversies regarding the clinical significance, postnatal evaluation, and management of neonates with ANH. Mild ANH will often resolve spontaneously, whereas moderate to severe ANH is frequently associated with CAKUT.

SUMMARY

ANH is a surrogate marker of potential congenital renal anomalies, but usually cannot identify a specific disease. A multidisciplinary team approach is required to diagnose and treat these complex disorders. Currently nonsurgical management of CAKUT should be considered whenever possible for infants with ANH.