Association of Ischemia-Modified Albumin (IMA) in Saliva, Serum, and Urine with Diagnosis of Chronic Kidney Disease (CKD) in Children: A Case-Control Study

BACKGROUND Ischemia-modified albumin (IMA) is a secreted biomarker for ischemic oxidative stress. This case-control study aimed to evaluate the association of ischemia-modified albumin (IMA) in saliva, serum, and urine with diagnosis of chronic kidney disease (CKD) in 24 children. MATERIAL AND METHODS The study involved 24 children with CKD. CKD was defined according to the Kidney Disease Improving Global Outcomes (KDIGO) diagnostic criteria. The control group consisted of 24 healthy children who were matched for age and gender to the experimental group. The concentration of IMA was determined by the colorimetric method in non-stimulated whole saliva (NWS), stimulated whole saliva (SWS), serum, and urine of children with CKD. The Mann-Whitney U test was used for inter-group comparisons. RESULTS IMA levels were significantly higher in NWS (P=0.0082) and SWS (P=0.0014) of children with CKD than in the control group. The concentration of IMA in NWS was correlated with standard indicators of kidney function, including the estimated glomerular filtration rate (r=-0.798, P≤0.0001), stage of CKD (r=0.814, P≤0.0001), and serum creatinine (r=0.711, P≤0.0001) and urea levels (r=0.738, P≤0.0001). CONCLUSIONS Salivary IMA concentration depends on renal function in children. Salivary IMA discriminates children with end-stage kidney disease from children with mild and moderate CKD and healthy children with high sensitivity and specificity. Further research is required, including assessment of the diagnostic usefulness and validation of the biomarker in a clinical diagnostic study.

Antibiotic Prophylaxis in Infants with Grade III, IV, or V Vesicoureteral Reflux

BACKGROUND

The efficacy of continuous antibiotic prophylaxis in preventing urinary tract infection (UTI) in infants with grade III, IV, or V vesicoureteral reflux is controversial.

METHODS

In this investigator-initiated, randomized, open-label trial performed in 39 European centers, we randomly assigned infants 1 to 5 months of age with grade III, IV, or V vesicoureteral reflux and no previous UTIs to receive continuous antibiotic prophylaxis (prophylaxis group) or no treatment (untreated group) for 24 months. The primary outcome was the occurrence of the first UTI during the trial period. Secondary outcomes included new kidney scarring and the estimated glomerular filtration rate (GFR) at 24 months.

RESULTS

A total of 292 participants underwent randomization (146 per group). Approximately 75% of the participants were male; the median age was 3 months, and 235 participants (80.5%) had grade IV or V vesicoureteral reflux. In the intention-to-treat analysis, a first UTI occurred in 31 participants (21.2%) in the prophylaxis group and in 52 participants (35.6%) in the untreated group (hazard ratio, 0.55; 95% confidence interval [CI], 0.35 to 0.86; P = 0.008); the number needed to treat for 2 years to prevent one UTI was 7 children (95% CI, 4 to 29). Among untreated participants, 64.4% had no UTI during the trial. The incidence of new kidney scars and the estimated GFR at 24 months did not differ substantially between the two groups. Pseudomonas species, other non-Escherichia coli organisms, and antibiotic resistance were more common in UTI isolates obtained from participants in the prophylaxis group than in isolates obtained from those in the untreated group. Serious adverse events were similar in the two groups.

CONCLUSIONS

In infants with grade III, IV, or V vesicoureteral reflux and no previous UTIs, continuous antibiotic prophylaxis provided a small but significant benefit in preventing a first UTI despite an increased occurrence of non-E. coli organisms and antibiotic resistance. (Funded by the Italian Ministry of Health and others; PREDICT ClinicalTrials.gov number, NCT02021006; EudraCT number, 2013-000309-21.).

Association Between Salivary Cytokines, Chemokines and Growth Factors and Salivary Gland Function in Children with Chronic Kidney Disease

Introduction

Chronic kidney disease (CKD) is a systemic inflammatory disease that leads to multiple organ complications not only in the kidneys and the cardiovascular system, but also in the oral cavity. CKD children experience reduced saliva secretion (hyposalivation), which leads to increased incidence of dental caries and significant impairment of patients' quality of life. However, the causes of salivary gland dysfunction in children with CKD are unknown. The present study is the first to evaluate the inflammatory and anti-inflammatory profile in the saliva of children with CKD at different stages of renal failure with normal and reduced salivary gland function.

Methods

Thirty children with CKD (age 9-16) and thirty age- and gender-matched healthy children were classified for the study. Salivary inflammatory and anti-inflammatory profile were assayed using the multiplex ELISA assay.

Results

We demonstrated statistically significant changes in salivary pro-inflammatory (↑TNF-α, ↓IL-7), anti-inflammatory (↑IL-10), Th1 (↑INF-γ, ↑IL-15), Th2 (↑IL-4, ↑IL-5, ↑IL-6, ↑IL-9) and Th17 (IL-17) cytokines as well as chemokines (↑MCP-1/CCL-2, ↑MIP-1α/CCL3, ↓MIP-1β/CCL4, ↓EOTAXIN/CCL11) and growth factors (↑G-CSF, ↑FGF) in unstimulated saliva of children with CKD compared to the controls. Although the evaluation of the salivary inflammatory profile does not indicate a particular dominance of any of the branches of the immune system, we observed a statistically significant increase in the concentration of all Th2 cytokines assayed. The multivariate regression analysis showed that the content of salivary cytokines, chemokines and growth factors depends on the secretory function of the salivary glands, ie, salivary flow, total protein concentration and amylase activity in the saliva. Salivary MIP-1α/CCL3 was the most effective to differentiate children with CKD and hyposalivation from patients with normal saliva secretion.

Discussion

Inflammation is involved in salivary gland dysfunction in children with CKD, although further studies on in vitro and in vivo models are necessary to confirm this hypothesis.

Genome-wide association study in patients with posterior urethral valves

Congenital lower urinary tract obstructions (LUTO) are most often caused by posterior urethral valves (PUV), a male limited anatomical obstruction of the urethra affecting 1 in 4,000 male live births. Little is known about the genetic background of PUV. Here, we report the largest genome-wide association study (GWAS) for PUV in 4 cohorts of patients and controls. The final meta-analysis included 756 patients and 4,823 ethnicity matched controls and comprised 5,754,208 variants that were genotyped or imputed and passed quality control in all 4 cohorts. No genome-wide significant locus was identified, but 33 variants showed suggestive significance (P < 1 × 10^-5). When considering only loci with multiple variants residing within < 10 kB of each other showing suggestive significance and with the same effect direction in all 4 cohorts, 3 loci comprising a total of 9 variants remained. These loci resided on chromosomes 13, 16, and 20. The present GWAS and meta-analysis is the largest genetic study on PUV performed to date. The fact that no genome-wide significant locus was identified, can be explained by lack of power or may indicate that common variants do not play a major role in the etiology of PUV. Nevertheless, future studies are warranted to replicate and validate the 3 loci that yielded suggestive associations.

Clinical and Epidemiological Analysis of Children's Urinary Tract Infections in Accordance with Antibiotic Resistance Patterns of Pathogens

The study was conducted to analyze urinary tract infections (UTI) in children by considering epidemiology and antibiotic resistance patterns of pathogens in accordance with inflammatory parameters. The research included 525 patients who demonstrated 627 episodes of UTI. The increasing resistance of bacteria was observed over the years covered by the study (p < 0.001). There was a significant increase of resistance to amoxicillin with clavulanic acid (p = 0.001), gentamicin (p = 0.017) and ceftazidime (p = 0.0005). According to the CART method, we managed to estimate C-reactive protein (CRP), procalcitonin (PCT) and white blood cell (WBC) values, in which antibiotic sensitivity was observed. In children with CRP > 97.91 mg/L, there was a high percentage of sensitive cases to amoxicillin with clavulanic acid (87.5%). Values of WBC above 14.45 K/µL were associated with E. coli more sensitivity to ampicillin. 100% of children with CRP > 0.42 mg/L and PCT ≤ 6.92 ng/mL had confirmed sensitivity to cefuroxime. Concerning sensitivity to gentamicin, the most optimal cut-off point of WBC was >7.80 K/µL, while in the case of nitrofurantoin, it was CRP value > 0.11 mg/L (which was presented in 98.50% of children). These results may guide us with antibiotic therapy and help to inhibit increasing antibiotic resistance.

Genome-Wide Survey for Microdeletions or -Duplications in 155 Patients with Lower Urinary Tract Obstructions (LUTO)

Lower urinary tract obstruction (LUTO) is, in most cases, caused by anatomical blockage of the bladder outlet. The most common form are posterior urethral valves (PUVs), a male-limited phenotype. Here, we surveyed the genome of 155 LUTO patients to identify disease-causing CNVs. Raw intensity data were collected for CNVs detected in LUTO patients and 4.392 healthy controls using CNVPartition, QuantiSNP and PennCNV. Overlapping CNVs between patients and controls were discarded. Additional filtering implicated CNV frequency in the database of genomic variants, gene content and final visual inspection detecting 37 ultra-rare CNVs. After, prioritization qPCR analysis confirmed 3 microduplications, all detected in PUV patients. One microduplication (5q23.2) occurred de novo in the two remaining microduplications found on chromosome 1p36.21 and 10q23.31. Parental DNA was not available for segregation analysis. All three duplications comprised 11 coding genes: four human specific lncRNA and one microRNA. Three coding genes (FBLIM1, SLC16A12, SNCAIP) and the microRNA MIR107 have previously been shown to be expressed in the developing urinary tract of mouse embryos. We propose that duplications, rare or de novo, contribute to PUV formation, a male-limited phenotype.

Galectin-3-A New Player of Kidney Damage or an Innocent Bystander in Children with a Single Kidney?

The aim of this study was to evaluate the galectin-3 (Gal-3) level in children with a congenital solitary functioning kidney (cSFK) and determine its association with common renal function parameters. The study consisted of 68 children (49 males) with cSFK. We demonstrated that children with cSFK had a lower level of galectin-3 than that of healthy subjects (p < 0.001). No significant differences in serum cystatin C (Cys C) levels between the cSFK children and the reference group were found. The subjects with cSFK and reduced estimated glomerular filtration rate (eGFR) had significantly higher levels of Gal-3 and Cys C compared to those with normal eGFR (p < 0.05). Children with eGFR <60 mL/min/1.73 m² showed significant statistical differences between the values of area under ROC curve (AUC) for Gal-3 (AUC 0.91) and Cys C (AUC 0.96) compared to that for creatinine level (AUC 0.76). Similar analyses carried out among cSFK children with eGFR <90 mL/min/1.73 m² revealed an AUC value of 0.69 for Gal-3, 0.74 for Cys C, and 0.64 for creatinine; however, no significant superiority was shown for any of them. The receiver operating characteristic (ROC) analyses for identifying the SFK children among all participants based on the serum levels of Gal-3 and Cys C did not show any diagnostic profile (AUCs for Gal-3 and Cys C were 0.22 and 0.59, respectively). A positive correlation between the Gal-3 and Cys C concentrations was found (r = 0.39, p = 0.001). We demonstrated for the first time that Gal-3 might play an important role in the subtle kidney damage in children with cSFK. However, further prospective studies are required to confirm the potential applicability of Gal-3 as an early biomarker for kidney injury and possible progression to CKD.

Urine NGAL and KIM-1-Tubular Injury Biomarkers in Long-Term Survivors of Childhood Solid Tumors: A Cross-Sectional Study

The deterioration of renal function after childhood solid tumors treatment is the result of using the intensive multimodal therapy. In recent years, urinary kidney injury molecule-1 (KIM-1) and urinary neutrophil gelatinase-associated lipocalin (NGAL) have been introduced as potential promising biomarkers of early kidney damage. The aim of the present study was to determine whether anticancer treatment has any effect on the concentration of KIM-1 and NGAL and its association with renal impairment in survivors of childhood solid tumors. Sixty patients previously treated for solid tumors were involved in this study. The median time after end of treatment was 8.35 years. Urine KIM-1 and NGAL levels were measured using immunoenzymatic ELISA commercial kits. Higher levels of urine NGAL, KIM-1/cr. (creatinine), and NGAL/cr. ratios were found in comparison with healthy controls (p < 0.0001). Among all subjects, 23% were found to have decreased estimated glomerular filtration rate (eGFR). A strong correlation between KIM-1/cr. and a cumulative dose of ifosfamide was observed (r = 0.865, p < 0.05). In addition, a moderate correlation between NGAL/cr. and a cumulative dose of cisplatin was identified (r = 0.534, p < 0.05). The AUC for KIM-1/cr. was 0.52, whereas NGAL/cr. showed a diagnostic profile describing the AUC of 0.67. Univariable regression showed significant associations between NGAL/cr. ratio and subjects after unilateral nephrectomy (coeff. 63.8, p = 0.007), cumulative dose of cisplatin (coeff. 0.111, p = 0.033), and age at diagnosis (coeff. 3.75, p = 0.023). The multivariable model demonstrated only cumulative dose of cisplatin as an independent factor influence on NGAL/cr. ratio. The results of our study showed increased levels of urine KIM-1 and NGAL many years after completion of the childhood solid tumors treatment, which correlated positively with a cumulative dose of ifosfamide and cisplatin. This study also suggests that unilateral nephrectomy could affect the concentration of the studied biomarkers.

Low-Dose Antibiotic Prophylaxis Induces Rapid Modifications of the Gut Microbiota in Infants With Vesicoureteral Reflux

Background and Objectives: Maturation of the gut microbiota (GM) in infants is critically affected by environmental factors, with potential long-lasting clinical consequences. Continuous low-dose antibiotic prophylaxis (CAP) is the standard of care for children with vesicoureteral reflux (VUR), in order to prevent recurrent urinary tract infections. We aimed to assess short-term GM modifications induced by CAP in infants. Methods: We analyzed the GM structure in 87 infants (aged 1-5 months) with high-grade VUR, previously exposed or naïve to CAP. Microbial DNA was extracted from stool samples. GM profiling was achieved by 16S rRNA gene-based next-generation sequencing. Fecal levels of short- and branched-chain fatty acids were also assessed. Results: 36/87 patients had been taking daily CAP for a median time of 47 days, while 51/87 had not. In all patients, the GM was predominantly composed by Bifidobacteriaceae and Enterobacteriaceae. Subgroup comparative analysis revealed alterations in the GM composition of CAP-exposed infants at phylum, family and genus level. CAP-exposed GM was enriched in members of Enterobacteriaceae and Bacteroidetes, especially in the genera Bacteroides and Parabacteroides, and showed a trend toward increased Klebsiella, often associated with antibiotic resistance. In contrast, the GM of non-CAP children was mostly enriched in Bifidobacterium. No differences were found in fatty acid levels. Conclusions: In infants with VUR, even a short exposure to CAP definitely alters the GM composition, with increased relative abundance of opportunistic pathogens and decreased proportions of health-promoting taxa. Early low-dose antibiotic exposure might bear potential long-term clinical risks.

Mild X-linked Alport syndrome due to the COL4A5 G624D variant originating in the Middle Ages is predominant in Central/East Europe and causes kidney failure in midlife

A study of 269 children enrolled into a National Registry for children with persistent glomerular hematuria identified 131 individuals with genetically confirmed X-linked Alport Syndrome. A single variant c.1871G>A p.Gly624Asp (G624D) in COL4A5 was predominant and accounted for 39% of X-linked Alport Syndrome in unrelated Polish families (44 of 113). To evaluate its origins, the genetic variation in a 2.79 Mb segment encompassing the COL4A5 locus on chromosome X was assessed. All G624D alleles were found on the same rare haplotype background, indicating a founder effect dating back to the 12-13th century. The phenotypic data of 131 children with X-linked Alport Syndrome and their 195 affected adult relatives revealed that the G624D variant was associated with a significantly milder clinical course in comparison to other pathogenic COL4A5 variants. Furthermore the clinical course of this genetically uniform cohort was milder than that observed in individuals with other COL4A5 missense mutations. In spite of the benign clinical manifestation throughout childhood and early adulthood, the G624D variant confers significant risk for both kidney failure and deafness in males, albeit 20-30 years later than that observed in individuals with other COL4A5 pathogenic variants (50% cumulative risk of starting dialysis at 54 years (95% confidence interval: 50-62) v. 26 years (95% confidence interval: 22-30)). Thus, males with G624D are candidates for existing and emerging therapies for Alport Syndrome.

Tumour necrosis factor-like weak inducer of apoptosis (TWEAK) in kidney disease: a biomarker or therapeutic target?

Kidney disease is a significant public health problem that is increasing worldwide. Tumour necrosis factor superfamily molecules have recently been shown to be actively involved in renal pathophysiology. According to current reports, one of these molecules has significant clinical implications: TWEAK, a tumour necrosis factor-like weak inducer of apoptosis. TWEAK is a cytokine with important functions. By binding to induced fibroblast growth factor 14 (Fn14), its only receptor, TWEAK activates various biological processes, including cell growth, migration or death, angiogenesis and production of proinflammatory cytokines. TWEAK and Fn14 expression is relatively low in healthy tissues. Experimental studies have confirmed the important role of TWEAK/Fn14 pathway activation in physiological tissue repair and regeneration, while its excessive activation leads to acute and/or chronic damage. TWEAK production takes place in various inflammatory diseases of the kidneys with the participation of immune cells. In the case of inflammatory diseases characterised by increased chemokine production, TWEAK presents with apoptotic effects. In non-immune diseases, TWEAK stimulates renal tubular proliferation. The dualism of the TWEAK effect is multifactorial. TWEAK was proliferative in healthy kidneys and in a compensatory overgrowth model after nephrectomy in which inflammatory cytokine expression was low. Data obtained from experimental and clinical studies are useful for developing future diagnostic and therapeutic strategies focused on the role of TWEAK in kidney damage.

Severe neurological outcomes after very early bilateral nephrectomies in patients with autosomal recessive polycystic kidney disease (ARPKD)

To test the association between bilateral nephrectomies in patients with autosomal recessive polycystic kidney disease (ARPKD) and long-term clinical outcome and to identify risk factors for severe outcomes, a dataset comprising 504 patients from the international registry study ARegPKD was analyzed for characteristics and complications of patients with very early (≤ 3 months; VEBNE) and early (4–15 months; EBNE) bilateral nephrectomies. Patients with very early dialysis (VED, onset ≤ 3 months) without bilateral nephrectomies and patients with total kidney volumes (TKV) comparable to VEBNE infants served as additional control groups. We identified 19 children with VEBNE, 9 with EBNE, 12 with VED and 11 in the TKV control group. VEBNE patients suffered more frequently from severe neurological complications in comparison to all control patients. Very early bilateral nephrectomies and documentation of severe hypotensive episodes were independent risk factors for severe neurological complications. Bilateral nephrectomies within the first 3 months of life are associated with a risk of severe neurological complications later in life. Our data support a very cautious indication of very early bilateral nephrectomies in ARPKD, especially in patients with residual kidney function, and emphasize the importance of avoiding severe hypotensive episodes in this at-risk cohort.

Salivary Gland Dysfunction, Protein Glycooxidation and Nitrosative Stress in Children with Chronic Kidney Disease

This study is the first to evaluate protein glycooxidation products, lipid oxidative damage and nitrosative stress in non-stimulated (NWS) and stimulated whole saliva (SWS) of children with chronic kidney disease (CKD) divided into two subgroups: normal salivary secretion (n = 18) and hyposalivation (NWS flow < 0.2 mL min-1; n = 12). Hyposalivation was observed in all patients with severe renal failure (4-5 stage CKD), while saliva secretion > 0.2 mL/min in children with mild-moderate CKD (1-3 stage) and controls. Salivary amylase activity and total protein content were significantly lower in CKD children with hyposalivation compared to CKD patients with normal saliva secretion and control group. The fluorescence of protein glycooxidation products (kynurenine, N-formylkynurenine, advanced glycation end products), the content of oxidative damage to lipids (4-hydroxynonneal, 8-isoprostanes) and nitrosative stress (peroxynitrite, nitrotyrosine) were significantly higher in NWS, SWS, and plasma of CKD children with hyposalivation compared to patients with normal salivary secretion and healthy controls. In CKD group, salivary oxidation products correlated negatively with salivary flow rate, -amylase activity and total protein content; however, salivary oxidation products do not reflect their plasma level. In conclusion, children with CKD suffer from salivary gland dysfunction. Oxidation of salivary proteins and lipids increases with CKD progression and deterioration of salivary gland function.

A Case-Control Study of Salivary Redox Homeostasis in Hypertensive Children. Can Salivary Uric Acid be a Marker of Hypertension?

Oxidative stress plays a critical role in the pathogenesis of hypertension; however, there are no data on salivary redox homeostasis and salivary gland function in children with hypertension. A total of 53 children with hypertension and age- and sex-matched controls were classified for the study. The antioxidant barrier and oxidative/nitrosative stress were evaluated in non-stimulated (NWS) and stimulated (SWS) whole saliva, plasma, and erythrocytes, with Student's t-test and Mann-Whitney U-test used for statistical analysis. We demonstrated that the activities of superoxide dismutase, catalase, and peroxidase were significantly higher in NWS, SWS, and erythrocytes of children with hypertension, similar to oxidative damage in proteins (advanced glycation end products) and lipids (malondialdehyde) as well as nitrosative stress markers (peroxynitrite and nitrotyrosine). The level of uric acid (UA) was significantly higher in NWS, SWS, and plasma of children with hypertension. UA concentration in SWS correlated positively with systolic and diastolic blood pressure and UA content in plasma. This parameter differentiates children with hypertension from healthy controls (AUC = 0.98) with a high degree of sensitivity (94%) and specificity (94%). Stimulated salivary flow was significantly lower in the hypertension group, similar to total protein content and salivary amylase activity. In summary, childhood hypertension is associated with hyposalivation as well as disturbances in antioxidant defense and enhanced oxidative/nitrosative damage both in the plasma/erythrocytes as well as saliva. Salivary UA may be a potential biomarker of hypertension in children.

Salivary FRAP as A Marker of Chronic Kidney Disease Progression in Children

Chronic kidney disease (CKD) is one of the most common modern-age diseases in children. Kidney failure does not reveal any symptoms for a long time; therefore, new biomarkers are sought, preferably those reflecting an early stage of CKD. The aim of our study was to evaluate total antioxidant potential as a biomarker differentiating the degree of CKD advancement. The study included 30 children with CKD and a control group matched by age and gender. Non-stimulated saliva (NWS), stimulated saliva (SWS), plasma and urine were used as study material. Total antioxidant potential was determined spectrophotometrically using the FRAP method (ferric ion reducing antioxidant parameter) by measuring total FRAP and uric acid (UA)-independent FRAP (FRAP-UA). We demonstrated that total FRAP, FRAP-UA and UA were significantly higher in stimulated saliva, as well as urine of CKD patients compared to the controls. These biomarkers increase with the progression of chronic kidney disease and their concentration in SWS reflects their content in urine. Interestingly, salivary FRAP and uric acid clearly differentiate between various stages of CKD as well as between healthy and ill children. Special attention should be paid to total FRAP which-measured in SWS-distinguishes patients with mildly to moderately decreased kidney function from those with severe renal impairment (AUC = 1, sensitivity = 100%, specificity = 100%). Although salivary FRAP may be a potential CKD biomarker in children, further studies are needed in a larger group of patients.

Rare Variants in BNC2 Are Implicated in Autosomal-Dominant Congenital Lower Urinary-Tract Obstruction

Congenital lower urinary-tract obstruction (LUTO) is caused by anatomical blockage of the bladder outflow tract or by functional impairment of urinary voiding. About three out of 10,000 pregnancies are affected. Although several monogenic causes of functional obstruction have been defined, it is unknown whether congenital LUTO caused by anatomical blockage has a monogenic cause. Exome sequencing in a family with four affected individuals with anatomical blockage of the urethra identified a rare nonsense variant (c.2557C>T [p.Arg853^∗]) in BNC2, encoding basonuclin 2, tracking with LUTO over three generations. Re-sequencing BNC2 in 697 individuals with LUTO revealed three further independent missense variants in three unrelated families. In human and mouse embryogenesis, basonuclin 2 was detected in lower urinary-tract rudiments. In zebrafish embryos, bnc2 was expressed in the pronephric duct and cloaca, analogs of the mammalian lower urinary tract. Experimental knockdown of Bnc2 in zebrafish caused pronephric-outlet obstruction and cloacal dilatation, phenocopying human congenital LUTO. Collectively, these results support the conclusion that variants in BNC2 are strongly implicated in LUTO etiology as a result of anatomical blockage.

Urinary procollagen III aminoterminal propeptide and β-catenin - New diagnostic biomarkers in solitary functioning kidney?

PURPOSE

We aimed at evaluating urinary levels of procollagen III aminoterminal propeptide (PIIINP) and β-catenin and the relationship between these markers and clinical and laboratory variables in children with a solitary functioning kidney (SFK).

PATIENTS AND METHODS

The study group consisted of 98 (M/F: 62/36) children with an SFK with a median age of 8 years. An age-matched control group contained 54 healthy peers. Urinary levels of procollagen III aminoterminal propeptide and β-catenin were measured using a commercially available immunoassay kit.

RESULTS

The urinary values of PIIINP (UPIIINP) were significantly increased in patients with SFK versus controls (p < 0.01). Our analysis revealed no significant differences in urinary β-catenin levels between the SFK patients and control subjects (p > 0.05). Only urinary PIIINP levels were correlated to renal function tests, such as serum creatinine, urea, uric acid, and estimated glomerular filtration rate (p<0.05).

CONCLUSIONS

An increased urinary level of PIIINP may indicate early kidney impairment in children with SFK. Urinary β-catenin does not seem to play any important role as a marker of renal function in children with SFK. Further long-term studies are required in order to evaluate the clinical usefulness of these markers and their predictive value of chronic kidney disease (CKD) progression.

Activity of lysosomal exoglycosidases in the urine of healthy normotensive and pre-hypertensive children

PURPOSE

We investigated the relationship between blood pressure (BP) and the activity of lysosomal exoglycosidases: N-acetyl-β-hexosaminidase (HEX), its isoenzymes A (HEX A) and B (HEX B), α-fucosidase (FUC), β-galactosidase (GAL), β-glucuronidase (GLU) and α-mannosidase (MAN) in pre-hypertensive (high normal blood pressure - HNBP) and normal blood pressure (NBP) children.

MATERIAL AND METHODS

The study was carried out with urine samples collected from 176 children, aged 6-17.9 years, divided into 2 groups: 42 HNBP and 134 NBP subjects. The children were stratified depending on systolic and diastolic BP (SBP; DBP): HNBP (SBP and/or DBP greater than or equal to the 90th percentile, but less than the 95th percentile) for sex, age, and height; and NBP (SBP and DBP less than the 90th centile). The activities of lysosomal exoglycosidases were determined by the colorimetric method, and expressed in pKat/mL and pKat/μgCr.

RESULTS

The activity of urinary HEX A in HNBP group was significantly higher than in NBP (p < 0.05). The HNBP group showed significant positive correlation between HEX, HEX A (pKat/mL) and SBP. AUC for HEX A was 0.616, cut-off value -29.351 pKat/mL (sensitivity 51.2%, specificity 71.8%), and 0.589, cut-off value -0.054 pKat/μgCr (sensitivity 31.7%, specificity 86.3%).

CONCLUSIONS

This is the first report of the relationship between BP and the activity of urinary lysosomal exoglycosidases: HEX, HEX A and HEX B, FUC, GAL, GLU, and MAN in healthy children and adolescents. It seems that HEX A (pKat/mL) can be used as a useful tool in identifying children with HNBP.

Urinary exoglycosidases, reference values in healthy children

PURPOSE

The purpose of the study was to determine the effect of age on lysosomal exoglycosidase activities: α-fucosidase, β-galactosidase, β-glucuronidase and α-mannosidase in healthy children and adolescents.

MATERIAL AND METHODS

Urine samples were collected from 203 healthy children and adolescents (girls = 99, boys = 104), aged six months to 17.9 years. The activities of α-fucosidase, β-galactosidase, β-glucuronidase and α-mannosidase were determined by colorimetric method and expressed in pKat/μg of creatine (pKat/μg Cr.).

RESULTS

Urinary α-fucosidase, β-galactosidase, β-glucuronidase and α-mannosidase activities (pKat/μg Cr.) were the highest in children below 3 years of age in comparison to the remaining age groups. There was a statistically significant negative correlation between urinary α-fucosidase, β-galactosidase, β-glucuronidase and α-mannosidase (pKat/μg Cr.) and age (r = -0.36; r = -0.36; r = -0.35; r = -0.35; at p < 0.0001, respectively). In addition, we constructed the reference values for urinary activity of α-fucosidase, β-galactosidase, β-glucuronidase and α-mannosidase (pKat/μg Cr.) in percentiles according to age in 3-year intervals.

CONCLUSIONS

Our study is the first to show reference values for urinary α-fucosidase, β-galactosidase, β-glucuronidase and α-mannosidase in children and adolescents.

Risk Factors for Early Dialysis Dependency in Autosomal Recessive Polycystic Kidney Disease

OBJECTIVE

To identify prenatal, perinatal, and postnatal risk factors for dialysis within the first year of life in children with autosomal recessive polycystic kidney disease (ARPKD) as a basis for parental counseling after prenatal and perinatal diagnosis.

STUDY DESIGN

A dataset comprising 385 patients from the ARegPKD international registry study was analyzed for potential risk markers for dialysis during the first year of life.

RESULTS

Thirty-six out of 385 children (9.4%) commenced dialysis in the first year of life. According to multivariable Cox regression analysis, the presence of oligohydramnios or anhydramnios, prenatal kidney enlargement, a low Apgar score, and the need for postnatal breathing support were independently associated with an increased hazard ratio for requiring dialysis within the first year of life. The increased risk associated with Apgar score and perinatal assisted breathing was time-dependent and vanished after 5 and 8 months of life, respectively. The predicted probabilities for early dialysis varied from 1.5% (95% CI, 0.5%-4.1%) for patients with ARPKD with no prenatal sonographic abnormalities to 32.3% (95% CI, 22.2%-44.5%) in cases of documented oligohydramnios or anhydramnios, renal cysts, and enlarged kidneys.

CONCLUSIONS

This study, which identified risk factors associated with onset of dialysis in ARPKD in the first year of life, may be helpful in prenatal parental counseling in cases of suspected ARPKD.

Pediatric reference data on activity of urinary N-acetyl-β-D-hexosaminidase and its isoenzymes

PURPOSE

The objective of the study was to establish age - dependent values of the urinary lysosomal exoglycosidases activities: N-acetyl-β-D-hexosaminidase (HEX) and its isoenzyme A (HEX A) as well as isoenzyme B (HEX B) in healthy children and adolescents.

MATERIAL AND METHODS

The study was performed using a random sample of 203 healthy children and adolescents (girls=99, boys=104), aged six months to 17.9 years. The activities of HEX, HEX A and HEX B were determined by a colorimetric method. The activities of the urinary HEX and its isoenzymes were expressed in pKat/μg of creatinine (pKat/μg Cr).

RESULTS

Median concentrations of urinary HEX, and its HEX A, HEX B isoenzymes in particular age groups were analyzed using ANOVA. Urinary HEX, HEX A and HEX B activities (pKat/μg Cr) were the highest in children below 3 years, in comparison to remaining age groups. There were statistically significant negative correlations between urinary HEX, HEX A as well as HEX B and age (r=-0.24, p<0.001 (HEX); r=-0.20, p<0.01 (HEX A); r=-0.26, p<0.001 (HEX B), respectively. We constructed the reference values for urinary activity of HEX, HEX A and HEX B (pKat/μg Cr) in centiles according to age, in three-year intervals.

CONCLUSIONS

Reported data present, for the first time, reference values for urinary activities of HEX and its isoenzymes HEX A and HEX B in children and adolescent.

Determining normal values of urinary phosphorus excretion in 3913 healthy children aged 2-18 to aid early diagnosis and treatment for urolithiasis

AIM

This study determined the specific reference values for urinary phosphorus excretion in healthy children and adolescents aged 2-18 years and evaluated whether they changed with age during growth and were gender dependent.

METHODS

We enrolled 3913 healthy children and adolescents aged 2-18 years to this study. The study population was divided into age groups, and the analysis was performed in one-year periods, separately for boys and girls. Urinary phosphorus excretion was analysed using four categories: P1 in mmol/24 hour units, P2 in mmol/kg/24 hours, P3 in mmol/1.73 m² /24 hours and P4 in mmol/mmol creatinine.

RESULTS

Clear differences in urinary exertion for girls and boys were observed as well as systematic changes with age. The boys presented with significantly higher daily urinary phosphorus excretion independent of its manner of expression (p < 0.001). The median urinary phosphorus (P1) rose with age (p < 0.001). Percentile tables of phosphorous exertion are presented.

CONCLUSION

This was the largest study of urinary phosphate excretion based on a randomly selected sample of girls and boys aged 2-18 years. It highlights the importance of determining phosphorus reference values for children of different ages to provide early diagnosis and treatment for urolithiasis.

Renalase Levels in Children with Solitary Functioning Kidney

OBJECTIVE

To measure serum and urine renalase levels in children with a single kidney, and to compare with a reference group.

METHODS

Participants were: solitary kidney (n=36) and healthy children (n=57). Renalase levels were measured using the immunoenzymatic method.

RESULTS

Serum and urine renalase levels were significantly lower in patients with a solitary kidney compared to healthy children. Urine renalase/creatinine values were negatively related to serum creatinine and positively related to glomerular filtration rate. Significant correlations between renalase levels and blood pressure were not found.

CONCLUSION

Prognostic importance of reduced renalase levels in children with a single kidney can only be quantified by further longitudinal study.

Is urine intercellular adhesion molecule-1 a marker of renal disorder in children with ureteropelvic junction obstruction?

AIM

We aimed to investigate whether urine intercellular adhesion molecule-1 (ICAM-1) might serve as a marker of renal disorder in children with ureteropelvic junction obstruction.

MATERIAL AND METHODS

Twenty-nine children with severe hydronephrosis (HN) were compared with 23 participants with mild HN and with 19 healthy peers.

RESULTS

Urine ICAM-1/uCre levels were significantly higher in HN children than healthy controls (P<0.01), and in severe HN when compared with mild HN (p<0.05).

CONCLUSIONS

It seemed to us that uICAM-1 is a biomarker of renal disorder, and might have the potential to predict which patients will require surgery.

Urine exoglycosidases are potential markers of renal tubular injury in children with ureteropelvic junction obstruction

AIM

Hydronephrosis caused by ureteropelvic junction obstruction (UPJO) is an important problem in children and young adults. The aim of this pilot study was to determine the urine profiles of a number of lysosomal exoglycosidases to see whether they indicated tubular renal damage in children with UPJO.

METHODS

We measured lysosomal exoglycosidases urine activities in 32 patients with UPJO, dividing them into three groups. The surgical group comprised 16 children with severe hydronephrosis who required surgery, the nonsurgical group comprised 16 patients with mild hydronephrosis, and the reference group comprised 42 healthy children. The following indicators were measured: N-acetyl-β-hexosaminidase and its A and B isoenzymes, α-fucosidase, β-galactosidase, α-mannosidase and β-glucuronidase.

RESULTS

The urine activities of all exoglycosidases were significantly higher in children with UPJO than children in the reference group (p < 0.01). A strong positive correlation was also found between most of the urine exoglycosidases and the urine albumin/creatinine ratio (p < 0.01).

CONCLUSION

Our findings demonstrated that children with UPJO showed increased renal activities of assessed exoglycosidases, which correlated positively with the urine albumin/creatinine ratio. A larger multicentre study is required to confirm the clinical applications of these observations.

The effects of breastfeeding on serum asymmetric dimethylarginine levels and body composition in children

INTRODUCTION

The purpose of this work was to investigate the association of serum asymmetric dimethylarginine (ADMA) and high-sensitivity C-reactive protein (hs-CRP) levels with duration of breastfeeding and body composition in children.

PATIENTS AND METHODS

The study group consisted of 88 patients with a median age of 12 months (42 boys, 46 girls), classified as never breastfed or fully breastfed. ADMA and hs-CRP were measured by immunoenzymatic enzyme-linked immunosorbent assay commercial kits. Body composition analysis was performed by bioelectrical impedance.

RESULTS

We found significantly higher serum ADMA levels but not serum hs-CRP levels in never breastfed compared with the fully breastfed group (p<0.05). Serum ADMA was inversely associated with high-density lipoprotein-cholesterol levels and breastfeeding duration (p<0.05). Positive correlation was found between ADMA and body fat mass (p<0.05).

CONCLUSIONS

In never breastfed children, increased ADMA is observed; however, further studies are needed to assess whether breastfeeding duration affects body fat and body composition at older ages.

[The role of early-life metabolic programming in the pathogenesis of lifestyle diseases]

In recent years, a blooming period of genomics brings a window of opportunity to assess predispositions to some diseases in individuals, even before the first symptoms appear. However, a risk of becoming ill is more complex, as the gene expression is modified by epigenetic and environmental factors. Fetal development and first months of life are periods of dynamic growth and significant sensitivity to external factors. According to the theory of early-life metabolic programming, adaptive changes in these stages have lasting health effects. Among many environmental factors, the youngest children's diet plays an important role. Breastfeeding of newborns and infants is an essential part of lifestyle diseases prevention. Constantly increasing number of reports link natural nutrition of the youngest children with less risk of obesity, hypertension, dyslipidemia and insulin resistance in future life. However, further long-term studies taking into account number of bias factors, explaining protective mechanisms of human milk, are needed.

Increased circulating inflammatory markers may indicate that formula-fed children are at risk of atherosclerosis

AIM

The aim of this study was to determine whether formula-fed children have higher serum monocyte chemoattractant protein-1 (MCP-1) and uric acid levels than breast-fed children and to evaluate the association between these inflammatory markers and breastfeeding duration.

METHODS

The study group consisted of 87 patients aged between five and 32 months. Participants were divided into breast-fed and formula-fed groups and into age groups of ≤12 months and >12 months. MCP-1 was measured by the commercial immunoenzymatic ELISA kit, and uric acid was assessed using the colorimetric method.

RESULTS

Children in the formula-fed group had statistically significant higher serum MCP-1 and uric acid levels than breast-fed children (p < 0.01 and p < 0.05, respectively). Anthropometric parameters were comparable in both groups. Serum MCP-1 and uric acid levels were negatively correlated with duration of breastfeeding (p < 0.01 and p < 0.05). There was a positive relationship between serum MCP-1 and uric acid concentrations (r = 0.27, p < 0.05).

CONCLUSION

Increased circulating inflammatory markers may indicate that formula-fed children are at risk of atherosclerosis. However, further studies are needed.

Is symmetric dimethylarginine a sensitive biomarker of subclinical kidney injury in children born with low birth weight?

OBJECTIVE

The aim of this study was to investigate if Symmetric Dimethylarginine (SDMA) is a sensitive biomarker of renal function and may predict subclinical kidney injury in low birth weight (LBW) children.

METHODS

We studied 68 LBW children and 20 children as reference group. An enzyme-linked immunosorbent assay was used to measure serum SDMA and Cystatin C (Cys C).

RESULTS

SDMA levels were higher in study groups compared to reference groups. There was a strong correlation between SDMA and Cys C, also SDMA negatively correlated with eGFR.

CONCLUSION

Elevated SDMA concentration may play an important role in pathogenesis of chronic kidney disease.

New tubular injury markers in children with a solitary functioning kidney

BACKGROUND

The present study aimed to assess whether the urinary profiles of the lysosomal exoglycosidases N‑acetyl‑β‑hexosaminidase (HEX) and its isoenzymes A (HEX A) and B (HEX B), α-fucosidase (FUC), β-galactosidase (GAL), α-mannosidase (MAN), and β- glucuronidase (GLU) are useful biomarkers of tubular dysfunction in children with a solitary functioning kidney (SFK).

METHODS

We measured the urinary activity of HEX, its isoenzymes HEX A, HEX B, and FUC, GAL, MAN, and GLU in 52 patients with SFK. Patients were subdivided into two groups: congenital SFK (cSFK)-unilateral renal agenesis and acquired SFK (aSFK)-unilateral nephrectomy. The reference group (RG) contained 60 healthy sex- and age-matched children.

RESULTS

Urinary activity of all exoglycosidases in SFK was significantly higher than in RG (p < 0.05). There were no differences in exoglycosidase activity between cSFK and aSFK (p > 0.05). HEX and its isoenzymes HEX A and HEX B correlated negatively with estimated glomerular filtration rate (eGFR), and all estimated parameters correlated positively with albumin/creatinine ratio (p < 0.001).

CONCLUSION

Urinary activity of HEX, its isoenzymes HEX A and HEX B, and FUC, GAL, MAN, and GLU is elevated in children with SFK. Long-term follow-up studies in larger groups of children with SFK may help us to better understand their clinical significance.

Childhood-onset dense deposit disease: a rare cause of proteinuria

Introduction

Dense deposit disease (DDD) is a rare renal disease related to the dysregulation of the alternative pathway of the complement cascade, caused by several factors including the presence of an autoantibody to C3 nephritic factor, mutations in factor H and autoantibodies to this protein. DDD is characterized by C3 accumulation with absent or scanty immunoglobulin deposition.

Case Presentation

Herein we report the case of a child with benign course of DDD, who presented with moderate proteinuria and lack of clinical symptoms without immunosuppressive treatment. Laboratory testing revealed moderate proteinuria, normal serum creatinine, total protein, and albumin levels, but significantly decreased serum C3 level. The results of renal biopsy were consistent with DDD. Genetic analysis revealed that the patient carried one copy of the H402 risk allele of factor H. The level of proteinuria did not change during the follow-up period and no nephrotic syndrome signs occurred. Renal function was stable.

Conclusion

In conclusion, a program of urine screening for asymptomatic proteinuria and hematuria to detect children with kidney disease before they experience loss of kidney functions should be considered. Children diagnosed with DDD should have the opportunity to get treatment early on and to be followed very closely.

Urinary angiotensinogen as a novel marker of obstructive nephropathy in children

AIM

Obstructive nephropathy due to congenital or acquired urinary tract obstruction is one of the most important causes of chronic renal failure in children. There is a need for identification of new noninvasive urinary biomarkers to provide the clinician with fast, specific and reliable diagnostic and prognostic tool. The aim of the study was to determine whether urinary angiotensinogen (uAGT) may be a useful marker of obstruction in children with hydronephrosis (HN) caused by ureteropelvic junction obstruction (UPJO).

METHODS

The study cohort consisted of surgical group (SG): 31 children with severe HN who required surgery; nonsurgical group (NSG): 20 patients with mild HN, and reference group (RG): 19 healthy children. Urinary concentrations of angiotensinogen were measured using immunoenzymatic ELISA commercial kit and were expressed in ng/mg Cre (uAGT/uCre).

RESULTS

uAGT/uCre level was higher in SG when compared to NSG (p < 0.01) and healthy participants (SG vs. RG: p < 0.01). The difference between the uAGT/uCre in NSG and RG was not statistically significant (p > 0.05). uAGT/uCre was correlated negatively with differential renal function (r = -0.46; p < 0.01).

CONCLUSION

The present pilot study has clearly demonstrated that children with UPJO showed increased uAGT levels, which correlated negatively with differential renal function in radionuclide scan.

Osteopontin and symmetric dimethylarginine plasma levels in solitary functioning kidney in children

AIM

The present study aimed to examine whether plasma osteopontin (pOPN) and symmetric dimethylarginine (pSDMA) are useful biomarkers of renal dysfunction in children with solitary functioning kidney (SFK).

METHODS

We measured circulating pOPN and pSDMA in 51 patients with SFK and no other urinary defects. Patients were subdivided into two groups: primary SFK (pSFK) - unilateral renal agenesis (URA), and secondary SFK (sSFK) - unilateral nephrectomy. The control group (C) contained 21 healthy children, with mean age 9.92 ± 4.85 years. Immunoenzymatic ELISA commercial kits were used to measure pOPN and pSDMA concentrations.

RESULTS

Plasma osteopontin and pSDMA levels in children with SFK were higher than those in healthy participants (p < 0.05). There was no difference in pOPN and pSDMA concentrations between patients with pSFK and those with sSFK (p > 0.05). Receiver operator characteristic analyses performed to define the diagnostic efficiency of serum creatinine, pOPN and pSDMA in identifying children with C(cr)  < 90 mL/min/1.73 m(2) among all examined children revealed no differences between all three AUCs (p > 0.05).

CONCLUSION

Increased pOPN and pSDMA levels were observed in children with SFK. Both pOPN and pSDMA correlated with eGFR; however, the sensitivity and specificity of those markers were not better than those of creatinine.

Markers of systemic inflammation in children with hyperuricemia

AIM

The purpose of the study was to investigate serum concentrations of the monocyte chemoattractant protein-1 (MCP-1) and high-sensitivity CRP (hs-CRP) in children with hyperuricemia and to evaluate its association with obesity.

PATIENTS AND METHODS

The study involved 52 hyperuricemic patients with mean age of 15.53 ± 1.7 years. Twenty-seven healthy individuals with normal serum uric acid (SUA) level were selected as the control group (C). Serum MCP-1 and hs-CRP were measured by enzyme-linked immunosorbent assay (ELISA) and immunonephelometry, respectively.

RESULTS

Hyperuricemic patients showed increased sMCP-1 (median: 69.58 pg/mL) and hs-CRP (median: 0.53 mg/L) vs. controls (48.39 pg/mL, 0.24 mg/L; respectively) (p < 0.01). The obese children also presented significantly higher levels of sMCP-1 and hs-CRP (median, 81.69 and 1.18 mg/L, respectively) in comparison with nonobese (median, 59.62 and 0.41 mg/L, respectively; p < 0.01). Only hs-CRP correlated positively with body mass index Z-score (r = 0.33, p < 0.05). Receiver operator characteristic analyses checking the sensitivity and specificity of examined markers for hyperuricemia revealed the higher area under the curve (AUC) for sMCP-1; however, the difference between AUC for sMCP-1 and for hs-CRP was not significant (p > 0.05).

CONCLUSION

Serum MCP-1 and hs-CRP are elevated in hyperuricemic patients, but the role of obesity in inflammation markers needs further investigation.

Is plasma symmetric dimethylarginine a suitable marker of renal function in children and adolescents?

OBJECTIVE

The purpose of this cross-sectional study was to identify whether plasma symmetric dimethylarginine (pSDMA) is a useful marker of renal function in children.

MATERIAL AND METHODS

The study group consisted of 35 patients with chronic kidney disease (CKD) stages 1-5 (median age 11.5 years), classified on the basis of estimated glomerular filtration rate (eGFR) and divided into three groups: group A, patients with CKD stages 1 and 2; group B, CKD stage 3; and group C, CKD stages 4 and 5. A control group included 42 age-matched healthy children. Commercial enzyme-linked immunosorbent assay kits were used to measure pSDMA and serum cystatin C (sCysC) concentrations.

RESULTS

The pSDMA and sCysC levels were significantly elevated in all CKD patients in comparison with healthy controls (p < 0.05). The pSDMA level in children was increased in the mild CKD (group A) (p < 0.01). There were also a significant difference in pSDMA concentration between groups A and B (p < 0.01). No differences in pSDMA levels were found between groups B and C. Receiver operating characteristics analyses showed that pSDMA was a better diagnostic tool than sCysC for identifying CKD stage among all the examined children and for detecting patients from group A (eGFR >60 ml/min/1.73 m(2)).

CONCLUSIONS

Increased pSDMA and sCysC levels were found in CKD children. Further studies are required to confirm potential applications of pSDMA and CysC as useful biomarkers for the diagnosis and progression of CKD.

[Serum and urinary concentration of selected metalloproteinases and their tissue inhibitors in children with vesicoureteral reflux]

Vesicoureteral reflux (VUR) in children may lead to the renal fibrosis and scarring due to the overproduction and accumulation of extracellular matrix proteins (ECM) in interstitial tissue. Metalloproteinases produced in the kidneys are called biological markers of fibrosis. THE AIM OF THE STUDY was to assess if the presence of VUR in children disturb the balance between the serum and urinary concentrations of matrix metalloproteinases 2 and 9 and their tissue inhibitors 1 (TIMP-1) and 2 (TIMP-2) and predispose to excessive renal fibrosis. MATERIAL AND METHODS. The study was performed in 88 children, median aged 5.5 years (0.08-16 yrs) with VUR confirmed by voiding cystouretrography (VCUG). In 95% of estimated children the pyelonephritis indicated for VCUG performance. Control group consisted of 30 healthy children at similar age. Concentrations of MMP-2, MMP-9, TIMP-1 and TIMP-2 were estimated using immunoenzymatic ELISA method in urine of all examined children, additionally all the mentioned parameters in children with high (ll-V) grade of VUR were assessed in serum. RESULTS revealed that the urinary and serum concentrations of TIMP-1 and TIMP-2 were higher in healthy controls (p < 0.05). MMP-9 levels were higher only in the urine (p < 0.05) and MMP-2 in serum (p < 0.05). Increase in TIMP concentrations was connected with parallel increase in MMP levels in children with I-V grades of VUR, what was confirmed by the normal values of MMP-2/TIMP-2 and MMP-9/TIMP-1 ratios (p > 0.05). Only children with Ill-rd grade of VUR revealed reduced values of MMP/TIMP ratios (p < 0.05). Children's with Ill-V grade VUR revealed higher increase in serum concentrations of TIMP than in MMP, it was also seen in decrease in MMP/TIMP ratios (p < 0.05). No correlation was found between serum and urinary results of estimated parameters (p > 0.05).

CONCLUSION

MMP-2 and MMP-9 and TIMP-1 and TIMP-2 play role in pathogenesis of VUR disturbances, what was confirmed by the change in their serum and urinary concentrations. In serum and urine of children with high (Ill-V) grade VUR the biggest disturbances were observed in MMPs: TIMPs system with the TIMP levels higher than MMP values, what indirectly indicated ECM degradation disturbances and increase in renal fibrosis.

Neutrophil gelatinase-associated lipocalin (NGAL): a new marker of cyclosporine nephrotoxicity?

The aim of work was to investigate whether serum and urinary neutrophil gelatinase-associated lipocalin(sNGAL and uNGAL, respectively) are potential biomarkers of early cyclosporine A (CsA) nephrotoxicity in steroid-dependent nephrotic children (SDNS). The study group (I) consisted of 19 children with SDNS aged 9.46+/-5.52 years treated with CsA. The children were examined four times: at proteinuria relapse, prior to CsA treatment,then after 3, 6, and 12 months of CsA treatment. The control group (II) consisted of 18 healthy children aged 3-15 years. A commercial enzyme-linked immunosorbent assay method was used to measure NGAL concentration.The sNGAL level in SDNS children prior to the administration of CsA was similar to that in the healthy controls (p>0.05), but it increased significantly during the course of treatment (p<0.01). The uNGAL/creatinine (cr) ratio in SDNS patients was higher before the withdrawal of CsA therapy (p<0.05), and was also increased at the consecutive examinations (p<0.01). There was a positive correlation between both sNGAL and uNGAL levels and CsA serum level. However, based on the serum and urinary NGAL/cr receiver operating characteristic curve and area under the curve (AUC) analysis, it remains uncertain whether uNGAL is a good predictor of cyclosporine nephropathy. Both sNGAL and uNGAL concentrations increased during the course of CsA treatment. Further studies in larger groups of patients are therefore necessary to confirm our experimental data that increased NGAL levels may be a non-invasive marker for the early detection of tubulointerstitial damage in CsA nephrotoxicity.

Spontaneous urinary calcium oxalate crystallization in hypercalciuric children

Idiopathic hypercalciuria is the most important predisposing risk factor for calcium oxalate (CaOx) renal stone formation. We assessed the associations between spontaneous CaOx crystallization based on the Bonn Risk Index (BRI), urinary pH, calciuria, oxaluria, and citraturia in 140 Caucasian patients with hypercalciuria, aged 4-17 years, and compared the findings with those in 210 normocalciuric controls. Of the 140 hypercalciuric patients, 58 had renal stones, and 82 had recurrent erythrocyturia, renal colic, or urinary obstructive symptoms-but without stones. Urinary ionized calcium ([Ca(2+)]) levels were measured using a selective electrode, while the onset of crystallization was determined using a photometer and titration with 40 mmol/L ammonium oxalate (Ox(2-)). The calculation of the BRI was based on the [Ca(2+)]:Ox(2-) ratio. The BRI values were 12-fold higher in hypercalciuric children than in healthy controls, but no differences were found in the BRI between subjects with urinary stones and those with urolithiasis-like symptoms. An increased BRI suggested an association with hypercalciuria, lower urinary pH, hypocitraturia, and hypooxaluria. These data indicate that hypercalciuria is an important factor associated with increased urinary CaOx crystallization, although the causal pathways need further investigation. Determination of the BRI in children with hypercalciuria may improve the risk assessment of kidney stones.

[Matrix metalloproteinases 2 and 9 and their tissue inhibitors 1 and 2 in the urine of children with pyelonephritis]

In small children, pyelonephritis (PN) is an important cause of scarring in the renal and disturbed in the production and degradation of extracellulare matrix proteins (ECM). Aim of the study was to assess the urinary levels metalloproteinases 2 and 9 (MMP-2 and MMP-9) and their inhibitors 1 and 2 (TIMP-1 and TIMP-2) in children with pyelonephritis (PN).

MATERIALS AND METHODS

Study group (I) consisted of 42 children with PN, aged 1-15 years, examined twice: A--prior to treatment (1-3 days of fever), B--after antibacterial treatment (10-14 days). The control group (K) consisted of 30 healthy children. Enzyme-linked immunosorbent assay kits were used for measurements of total human MMP-2, MMP-9, TIMP-1 and TIMP-2 in first morning urine.

RESULTS

In children with PN (I) prior to treatment (A), urinary concentration of all parameters were increased as compared to the control (K) (p<0.05). After treatment (B), only the levels of TIMP-1 was still elevated (p = 0.02). In PN before (A) and after (B) treatment MMP-9/TIMP-1 ratio. However MMP-2/TIMP-2 ratio was normal.

CONCLUSION

In children with PN the balance MMP-9/TIMP-1 is disturbed, with the predominance of TIMP-1 production over MMP-9. It may lead to renal fibrosis.

[Urinary laminin and fibronectin level in children with nephritic syndrome]

Laminin (LN) and fibronectin (FN) are important extra cellular matrix (ECM) proteins. Disturbance between production and degradation of ECM proteins contributes to renal scarring. The aim of the study was evaluation the levels of urinary LN and FN in children with proteinuria in nephrotic syndrome (NS).

MATERIALS AND METHODS

Examinations were conducted on 71 children, 3-15 years old: (A)--44 children with NS (proteinuria above 50 mg/kg b.v./24 hours); (B)--27 children without proteinuria (remission NS). Control group (K)--30 healthy children. Concentration of LN and FN were determined by EIA.

RESULTS

In urine of children with NS (A) urinary concentration of LN significantly increased, in comparison to control (K) (p<0.05), but FN was normal (p>0.05). In children with remission of NS (B) urinary concentration of LN was unchanged (p>0.05), but concentration of FN significantly decreased (p<0.05). In renal biopsies majority children of A group presented minimal changes, but majority children of B group presented hyalinization of renal tubules.

CONCLUSION

Nephrotic proteinuria disturbs production of LN and increases its urinary excretion, but did not influence on urinary excretion of FN.

[Role of matrix metalloproteinases (MMP) and their tissue inhibitors (TIMP) in nephrology]

Metalloproteinases (MMP) and their tissue inhibitors (TIMP) play a crucial role to keep the balance between the synthesis and degradation of extracellular matrix protein. Balance disturbances of those two systems lead to abnormal tissue remodeling. There is evidence that matrix metalloproteinases activity changes in many pathological conditions, including inflammatory, degenerative disorders as well as tumor progression. Recent investigations indicate that MMPs and TIMPs play a pivotal role in pathogenesis of most of kidney diseases. Studies describing dysregulated activity of MMPs and/or their tissue inhibitors in various experimental and clinical models of kidney disease, including chronic kidney disease, glomerulonephritis, pyelonephritis, diabetic and hypertensive nephropathy, polycystic kidney disease and renal cancer are reviewed.

[Analysis of vesicoureteral reflux (VUR) course in children]

A small number of reports evaluating early effects of vesicoureteral reflux conservative therapy in children, based on antibacterial prophylaxis combined with correction of the of lower urinary tract function inspired us to perform the study. THE AIM OF THE STUDY was to assess the effects of vesicoureteral reflux (VUR) management in children according to grade, sex and way of treatment.

MATERIAL AND METHODS

The study group consisted of 108 children, who were treated in 2000-2007 due to VUR. There were 162 refluxing ureters (grades I-V) diagnosed by voiding cystourethrography (VCU). In 82 children cystometry and (or) uroflowmetry were additionally performed, which revealed lower urinary tract disorders in 41 (60 refluxing ureters), mostly detrusor hyperactivity or detrusor-sphincter dyscoordination. All children had conservative treatment, A - in 67 (102 refluxing ureters) only antibacterial prophylaxis, B - in 41 of children (60 refluxing ureters) in combination with pharmacological treatment of urodynamic abnormalities.

RESULTS

The check-up VCU was performed after 23+/-15 months on average. VUR was observed to subside in 44/162 (28%) of refluxing ureters, including 22/108 (22%) of those treated managed with method A and 22/60 (37%) with method B. Fifty three of refluxing ureters were qualified for further conservative therapy and 65/162 (40%) for surgery (especially endoscopic). Following 2-3 years medical and surgical treatment, 87/162 (54%) refluxing ureters resolved.

CONCLUSION

In the diagnostics of VUR in children we should take into consideration the assessment of lower urinary tract function, as treatment of these abnormalities increases the effects of VUR conservative management. However it should be confirmed on a larger group of patients.