Urinary Concentration of Renal Biomarkers in Healthy Term Neonates: Gender Differences in GST-pi Excretion

BACKGROUND Serum creatinine, the criterion standard in assessment of renal function, is not reliable for the neonatal period because of its dependence on renal immaturity and maternal creatinine levels. Thus, it is important to study other biomarkers of renal function in neonates. The present study aimed to measure the urinary concentration of renal biomarkers: calbindin, clusterin, GST-pi (glutathione-S-transferase-alpha), KIM-1 (kidney injury molecule 1), MCP-1 (monocyte chemoattractant protein-1), and B2M (beta 2-microglobulin) in healthy term neonates. MATERIAL AND METHODS In the study, we included 80 healthy term neonates - 40 females and 40 males. We collected the neonates' urine on their first day of life. Urinary concentrations of calbindin, clusterin, KIM-1, MCP-1, and B2M were assessed using an immunoassay for kidney toxicology research. Because dilution of the urine affects the concentrations of urinary biomarkers, we normalized them to the concentration of urinary creatinine (Cr) and present them as biomarker/Cr ratios. RESULTS We obtained the following values of the assessed biomarker/Cr ratios (median [Q1-Q3]): calbindin/Cr.: 197.04 (56.25-595.17), KIM-1/Cr: 0.09 (0.04-0.18), MCP-1/Cr: 0.05 (0.02-0.14), B2M/Cr: 126.12 (19.03-342.48), GST-pi/Cr in boys: 1.28 (0.46-3.77), GST-pi/Cr in girls: 8.66 (2.51-27.82), clusterin/Cr: 4.55 (1.79-12.97) ng/mg Cr. CONCLUSIONS We showed the urinary levels of calbindin, clusterin, GST-pi, KIM-1, MCP-1, B2M in white, West Slavic, healthy term neonates. We found that in there is an association between female sex and a higher urinary GST-pi excretion, but urinary excretion of calbindin, clusterin, KIM-1, MCP-1, and B2M is sex-independent. The urinary levels of the assessed biomarkers do not depend on the method of delivery.

Current Status of Protein Biomarkers in Urolithiasis-A Review of the Recent Literature

Urolithiasis is an increasingly common clinical problem worldwide. The formation of stones is a combination of metabolic status, environmental factors, family history and many other aspects. It is important to find new ways to quickly detect and assess urolithiasis because it causes sudden, severe pain and often comes back. One way to do this is by exploring new biomarkers. Current advances in proteomic studies provide a great opportunity for breakthroughs in this field. This study focuses on protein biomarkers and their connection to kidney damage and inflammation during urolithiasis.

The Outcome of Childhood Immunoglobulin A Nephropathy with Acute Kidney Injury at the Onset of the Disease-National Study

Introduction: IgA nephropathy (IgAN) is the most common glomerulonephritis worldwide. Decreased glomerular filtration rate is a known risk factor for disease progression. Aim: We aimed to examine factors that may contribute to disease progression in children that present with impaired eGFR at the onset of IgAN. Materials and methods: Of the 175 patients with IgAN from the Polish Registry of Children with IgAN and IgAVN, 54 (31%) patients with IgAN who had an onset of renal function impairment (GFR < 90 mL/min) were eligible for the study. All of them were analyzed for initial symptoms (GFR according to Schwartz formula, creatinine, proteinuria, IgA, C3), renal biopsy result with assessment by Oxford classification, treatment used (R-renoprotection, P-prednisone+R, Aza-azathioprine+P+R, Cyc-cyclophosphamide+P+R, CsA-cyclosporine+P+R, MMF-mycophenolate mofetil+P+R), and distant follow-up. Based on the GFR score obtained at the end, patients were divided into two groups: A-GFR > 90 mL/min and B-GFR < 90 mL/min. Results: In the study group, the mean age of onset was 12.87 ± 3.57 years, GFR was 66.1 ± 17.3 mL/min, and proteinuria was 18.1 (0-967) mg/kg/d. Renal biopsy was performed 0.2 (0-7) years after the onset of the disease, and MESTC score averaged 2.57 ± 1.6. Treatment was R only in 39% of children, P+R in 20%, Aza+P+R in 28%, Cyc+P+R in 9%, CsA+P+R in 7%, and MMF+P+R in 3%. The length of the observation period was 2.16 (0.05-11) years. At the follow-up, Group A had 30 patients (56%) and Group B had 24 patients (44%). There were no significant differences in any of the other biochemical parameters (except creatinine) or proteinuria values between the groups and the frequency of the MESTC score ≥ 2 and <2 was not significantly different between Groups A and B. Patients with normal GFR at the follow-up (Group A) were significantly more likely to have received prednisone and/or immunosuppressive treatment than those in Group B (p < 0.05) Conclusions: In a population of Polish children with IgAN and decreased renal function at the onset of the disease, 56% had normal GFR in remote observation. The use of immunosuppressive/corticosteroids treatment in children with IgAN and impaired glomerular filtration rate at the beginning of the disease may contribute to the normalization of GFR in the outcome, although this requires confirmation in a larger group of pediatric patients.

The Urinary Concentration of Trefoil Factor 3 (TFF3) in the Term and Preterm Neonates

BACKGROUND

Distinguishing between a pathologic state and renal development is important in neonatology. Because the assessment of serum creatinine in neonates is not reliable, better biomarkers are needed. Trefoil factor 3 (TFF3) is proposed as a biomarker of kidney injury. The study aimed to assess its urinary concentration in healthy term and stable preterm neonates.

MATERIAL AND METHODS

The study included 80 term and 20 preterm neonates born in the Department of Perinatology of the University Clinical Hospital in Bialystok. Urine was obtained from the term neonates on the 1st day of life and from the preterm neonates on the 1st, 8th, 15th and 22nd day of life. The urinary concentration of TFF3 was determined using a commercially available immunoassay and was normalized for the urinary creatinine concentration (cr.).

RESULTS

The values of TFF3/cr. were higher in the preterm than in the term neonates (p < 0.05) (median (Q1-Q3): 1486.85 (614.92-3559.18) and 317.29 (68.07-671.40) ng/mg cr.). They did not differ in the subsequent days of the preterm neonates' lives. The ROC curve for TFF3/cr. in the preterm and term neonates showed AUC = 0.751 (cut-off value = 1684.25 ng/mg cr.).

CONCLUSIONS

Prematurity is associated with higher urinary excretion of TFF3. Male gender is associated with an increased urinary TFF3 excretion in term neonates.

The Role of Complement Component C3 Activation in the Clinical Presentation and Prognosis of IgA Nephropathy-A National Study in Children

The aim of the study was to evaluate the influence of the intensity of mesangial C3 deposits in kidney biopsy and the serum C3 level on the clinical course and outcomes of IgAN in children. The study included 148 children from the Polish Pediatric IgAN Registry, diagnosed based on kidney biopsy. Proteinuria, creatinine, IgA, C3 were evaluated twice in the study group, at baseline and the end of follow-up. Kidney biopsy was categorized using the Oxford classification, with a calculation of the MEST-C score. The intensity of IgA and C3 deposits were rated from 0 to +4 in immunofluorescence microscopy. The intensity of mesangial C3 > +1 deposits in kidney biopsy has an effect on renal survival with normal GFR in children with IgAN. A reduced serum C3 level has not been a prognostic factor in children but perhaps this finding should be confirmed in a larger group of children.

Urinary excretion of renin and angiotensinogen in hypertensive children and adolescents

INTRODUCTION

In recent years hypertension has become an emerging condition in the young population. It has been proposed that the renin-angiotensin system plays an important role in regulation of blood pressure. We assessed whether activation of the intrarenal renin-angiotensin system occurs in hypertensive children and adolescents and what better reflects its activity: urine angiotensinogen (AGT) or urine renin (REN).

MATERIAL AND METHODS

The study was conducted on a sample of 58 subjects with primary hypertension (HT) and 29 normotensive children and adolescents. We measured urine REN and AGT excretion and assessed the values in relation to blood pressure (BP) and other clinical parameters. Both REN and AGT values were calculated by urine creatinine: REN/cr. and AGT/cr., respectively.

RESULTS

We observed higher urine REN/cr. values in hypertensive subjects in comparison to the reference group (6.99 vs. 2.93, p = 0.003). Hypertensive participants showed positive correlations between urine REN/cr. and diastolic 24-hour BP (r = 0.42, p = 0.002) as well as between urine REN/cr. and urine AGT/cr. (r = 0.266, p = 0.044, respectively).

CONCLUSIONS

Increased urine REN/cr. in hypertensive children and adolescents and its positive correlation with BP may indicate its important role in the pathogenesis of HT. Perhaps urine REN/cr. could be a marker of intrarenal renin-angiotensin system activity. Nevertheless, further research should be undertaken to confirm this observation.

Health-related quality of life in children with immunoglobulin A nephropathy - results of a multicentre national study

INTRODUCTION

Immunoglobulin A nephropathy (IgAN) may lead to end stage renal disease and severely affect patient functioning and wellbeing. The aim of the study was to evaluate health-related quality of life (HRQoL) in children and adolescents with IgAN, and compare HRQoL in relation to the disease course, social status and psychological factors, such as expressing anger and perceived personal competence.

MATERIAL AND METHODS

The multicentre cross-sectional study included 51 patients ≥ 8 years from 7 paediatric nephrology centres in Poland. Psychometric analysis was performed using the Kidscreen-52 questionnaire to evaluate HRQoL, the Anger Expression Scale to evaluate the severity of anger and the Personal Competence Scale to measure general perception of personal competence.

RESULTS

Mean age of patients was 14.54 ±3.69 years; duration since the diagnosis of IgAN was 4.98 ±3.9 years. Patients with IgAN rated their psychological wellbeing as significantly worse compared to healthy peers (p < 0.05). The presence of proteinuria was associated with significantly worse physical wellbeing (58.72 ±18.45 vs. 74.44 ±22.97; p < 0.05). Current therapy (steroids/immunosuppressive drugs) had no effect on HRQoL in the study group. Perceived personal competence was rated high by 49% of children in the study group. Children with IgAN were characterized by lower intensity of expressed anger (p < 0.001) and significantly higher intensity of suppressed anger (p < 0.01) compared to reference ranges. Severity of expressed anger correlated positively with the parent relations and school environment dimensions of HRQoL.

CONCLUSIONS

We found lower HRQoL in regard to physical and psychological wellbeing in a group of Polish children with IgAN compared to healthy peers. HRQoL should be monitored in this patient group.

[Liddle syndrome as a rare cause of hypertension - a case report]

Liddle syndrome is an uncommon genetic disorder featuring hypertension, hypokalemia, metabolic alcalosis, decreased rennin and aldosterone secretion. It is caused by a point mutation of a gene encoding one of the three subunits of the epithelial sodium channel (ENaC). Because of its rarity, the availability of the literature on the diagnosis of this syndrome is limited.

A CASE REPORT

The 14 years old adolescent with resistant hypertension was analyzed genetically, because of the family history. The significance of it and biochemical findings in recognition of Liddle Syndrome was discussed. It has been concluded that performing a genetic test at the suspicion of monogenic background of hypertension allows for accurate and effective treatment.

The Possible Impact of Hyperuricemia on Serum Soluble Receptor for Advanced Glycation end Products (sRAGE) Levels in Teenagers: A Case Control Study

BACKGROUND

Dietary advanced glycation end products (AGEs) and their interactions with the soluble receptors for AGEs (RAGE) play a crucial role in the pathogenesis of cardiovascular diseases.

OBJECTIVE

This study was set out to assess, whether there was any association between serum sRAGE level and serum uric acid level in children with hyperuricemia.

METHODS

This case-control study involved 53 patients (12 girls, 41 boys) with hyperuricemia (defined as serum uric acid >4.8 and >5.5 mg/dl in girls and boys, respectively) aged (median [IQR]) (15.5 [13.5-15.5] years). Thirty-six healthy individuals with normal serum uric acid level were selected as a reference group. Additionally, the study group with hyperuricemia was divided into two groups: HU-HT (hypertensive n=25) and HU-NT (normotensive n=28) teenagers. The serum concentration of human sRAGE was measured using a commercially available enzyme-linked immunosorbent assay (ELISA) kit.

RESULTS

We found statistically significant differences in serum sRAGE levels between normotensive subjects with hyperuricemia (median [IQR]) (169.8 [148.3-231.1] pg/ml) and reference group (median [IQR]) (129 [107.4-175.3] pg/ml), p<0.01. Univariate analysis of the data revealed a positive correlation between serum sRAGE and serum uric acid in the study group (r=0.306, p<0.05).

CONCLUSION

Our data showed that serum soluble receptors for AGEs are increased in teenagers with hyperuricemia. In contrast, neither hypertension nor increased BMI had a significant influence on serum sRAGE concentration. Further studies are needed to discover the possible mechanism on the influence of uric acid on sRAGE levels and to assess its possible clinical significance.

[Influence of intensity, localization and type of deposits in renal biopsy for disease symptoms and follow up in children with IgA nephropathy]

IgA nephropathy is the most common glomerulonephritis in the world. For diagnosis kidney biopsy is necessary.

AIM

The aim of the study was assessment the significance of IgA, C3 and IgG deposits intensity and location in kidney childhood IgA nephropathy (IgAN) for the symptoms of the disease and the follow up.

MATERIALS AND METHODS

Study population consisted of 81 children, average 11,45±3,99 years. IgAN was recognized based on renal biopsy, performed 1,2±1,84, median 0,5 years after the onset. We used Oxford classification (OC) to assess the severity of histopatological lesions. In renal biopsy IgA and C3 deposits were found in immunofluorescence in mesangium or in vessels of glomeruli or both, and intensity was defined 0 to +4. We analyzed: proteinuria (mg/kg/day), hematuria, creatinine, GFR (according to Schwartz formula) two times, at the onset of the disease (OOD) and at the follow up (FU). Patients were treated with: ACEI/ARB or steroids alone or with imunossupresion drugs: azathioprine (AZA), cyclophosphamide (CYC), cyclosporine A (CsA), mycopnenolate mophetil (MMF). The follow up was 3,31±2,88 years. We divided the patients into two groups, depending on the intensity of IgA deposits: G1 n=29 (+1/+2), G2 n=52 (+3/+4); depending on the localizations of these deposits, we analyzed 3 groups: A n= 39 (mesangium), B n= 15 (glomeruli vessels), C n=27 (both) and depending on the kind of deposits we analyzed 4 groups: gr. a - n=30 (only IgA), gr. b - n=37 (IgA+C3), gr. c - n=5 (IgA+IgG) gr. d - n= 9 (IgA+IgG+C3).

RESULTS

At OOD and FU we not found any differences in G1 vs G2 for: age, proteinuria, GFR and OC in renal biopsy; at FU GFR<90 ml/ min/1,73 m2 FU was observed more frequently in G2 vs G1 (p=0,02). The differences in groups A,B,C and groups a,b,c,d were not found.

CONCLUSIONS

Poor prognosis in childhood IgAN may also depend on the intensity of the deposits, irrespective of their location.

Urine fibroblast growth factor 23 levels in hypertensive children and adolescents

Aim

To determine the correlation of urinary fibroblast growth factor 23 (FGF23) excretion with blood pressure and calcium-phosphorus metabolism.

Methods

The study included 42 hypertensive (17 girls) and 46 healthy children and adolescents (17 girls) aged 6-18 years admitted to the Department of Pediatrics and Nephrology, Medical University of Białystok between January 2013 and December 2013. FGF23 in urine was measured using Human Intact FGF-23 ELISA Kit.

Results

Hypertensive participants had significantly higher urine FGF23/creatinine values than the reference group (8.65 vs 5.59 RU/mg creatinine, P = 0.007). Urine FGF23/creatinine positively correlated with systolic blood pressure in all participants. In hypertensive patients, urine FGF23/creatinine positively correlated with serum calcium and negatively with serum 25(OH)D, urinary calcium, phosphorus, and magnesium.

Conclusion

This study found that FGF23 may play an important role in the pathogenesis of hypertension in children and adolescents, but our results should be confirmed by further studies.

Increased Serum IgA in Children with IgA Nephropathy, Severity of Kidney Biopsy Findings and Long-Term Outcomes

The aim of the study was to determine whether an elevated IgA level at the time of the diagnosis of IgA nephropathy has an effect on the severity of kidney biopsy findings and long-term outcomes in children. We retrospectively studied 89 children with IgA nephropathy who were stratified into Group 1- elevated serum IgA and Group 2 - normal serum IgA at baseline. The level of IgA, proteinuria, hematuria, glomerular filtration rate (GFR) and hypertension (HTN) were compared at baseline and after the end of the follow-up period of 4.0 ± 3.1 years. Kidney biopsy findings were evaluated using the Oxford classification. The evaluation of treatment included immunosuppressive therapy and renoprotection with angiotensin converting-enzyme inhibitor (ACEI) or angiotensin II receptor blocker (ARB), or no treatment. The elevated serum IgA was found in 46 (52 %) patients and normal serum IgA level was found in 43 (48 %) patients. No differences were found between the two groups regarding the mean age of patients, proteinuria, and the number of patients with reduced GFR or HTN at baseline. In kidney biopsy, mesangial proliferation and segmental sclerosis were significantly more common in Group 1 compared with Group 2 (p < 0.05). Immunosuppressive therapy was used in 67 % children in Group 1 and 75 % children in Group 2. The Kaplan-Meier survival curves for renal function (with normal GFR) and persistent proteinuria did not differ significantly depending on the serum IgA level at baseline. We conclude that in IgA nephropathy the elevated serum IgA at baseline may be associated with mesangial proliferation and segmental sclerosis contribute to glomerulosclerosis, but has no effect on the presence of proteinuria or on the worsening of kidney function during several years of disease course.

Predictors of Progression in IgA Nephropathy in Childhood

The aim of this retrospective study was to assess the usefulness of potential predictors of poor prognosis in IgA nephropathy in children. The study population consisted of 55 children aged 11 ± 4 years, diagnosed on the basis of the Oxford classification and MEST score of kidney biopsy findings. Proteinuria, glomerular filtration rate (GFR), and the IgA/C3 serum ratio were assessed in all patients twice: at onset and at follow-up. The patients were treated with steroids, immunosuppressive drugs, and/or angiotensin-converting enzyme inhibitors. Follow-up was at 3.9 ± 2.9 (median 2.7) years. The patients were subdivided into two groups: with GFR <90 and ≥90 mL/min at follow-up. ROC AUC curves and logistic regression were used to evaluate the power of prognostic factors. The two groups did not differ regarding the level of proteinuria, MEST score, and the IgA/C3 ratio at onset of disease. There was a significant association between GFR reductions at onset and follow-up (AUC = 0.660; p < 0.05). In patients with nephrotic range proteinuria at onset, proteinuria at follow-up was more frequent compared with other patients (AUC = 0.760; p < 0.05), MEST score ≥3 tended to be associated with reduced GFR (AUC = 0.650; p = 0.07) but not with proteinuria (AUC = 0.608; p = 0.47), and the IgA/C3 ratio was higher (p < 0.05) at follow-up. No significant associations were found between the IgA/C3 ratio at onset and reduced GFR (AUC = 0.565; p = 0.46) or proteinuria at follow-up (AUC = 0.263; p = 0.20). We conclude that predictors of poor outcome in childhood IgAN include the following: GFR reduction, nephrotic range proteinuria at onset of disease, and high MEST score in Oxford classification of kidney biopsy. Despite a higher serum IgA/C3 ratio in children with impaired renal function in long-term follow-up, we failed to demonstrate a significant association between this ratio at onset of disease and reduced GFR or persistent proteinuria at follow-up. Thus, IgA/C3 ratio is not a good foreteller of progression of IgA nephropathy in childhood.

IgA Nephropathy in Children: A Multicenter Study in Poland

IgA nephropathy (IgAN) is the most common form of glomerulonephritis in pediatric population. The clinical presentation of the disease in children ranges from microscopic hematuria to end-stage kidney disease. The aim of the study was to retrospectively assess clinical and kidney biopsy features in children with IgAN. We assessed a cohort of 140 children, 88 boys, 52 girls with the diagnosis of IgAN in the period of 2000-2015, entered into the national Polish pediatric IgAN registry. The assessment included the following: proteinuria, hematuria, glomerular filtration rate (GFR), arterial blood pressure, and the renal pathological changes according to the Oxford classification and crescents formation, as modifiable and unmodifiable risk factors. The incidence of IgAN in Poland was set at 9.3 new cases per year. The mean age at onset of IgAN was 11.9 ± 4.3 years, and the most common presentation of the disease was the nephritic syndrome, recognized in 52 % of patients. Kidney biopsy was performed, on average, 1.3 ± 2.0 years after onset of disease. Based on the ROC analysis, a cut-off age at onset of disease for GFR <90 mL/min/1.73 m² (risk factor of progression) was calculated as 13.9 years. Unmodifiable lesions: segmental sclerosis, tubular atrophy/interstitial fibrosis (S1, T1-2) in the Oxford classification and crescents in kidney biopsy were significantly more common in Gr 1 (>13.9 years) compared with Gr 2 (<13.9 years), despite a significantly shorter time to kidney biopsy in the former. We conclude that IgAN in children may be an insidious disease. A regular urine analysis, especially after respiratory tract infections, seems the best way for an early detection of the disease.

[FGF23 and Klotho protein--the role in the pathogenesis of hypertension]

Fibroblast growth factor 23 (FGF23) is a relatively new phosphatonin, which is produced mainly by bone cells. It is responsible for the regulation of calcium- phosphate homeostasis in the body. FGF23 is one of hormones with phosphaturic effect. It inhibits renal reabsorbtion of phosphate and increases its urinary excretion. Moreover, FGF23 decreases serum concentration of 1,25(OH)2D by inhibition of lα-hydroxylase and stimulation of 24-hydroxylase. The current knowledge on FGF23 and its cofactor-Klotho protein in disturbances of calcium-phosphate balance or in Chronic Kidney Disease is quite obvious. Still we need to know more about the influence of FGF23 on the cardiovascular system and its role in the pathogenesis of hypertension thus this will be the main aspect of our study.

Are oxidized low-density lipoprotein and C-reactive protein markers of atherosclerosis in nephrotic children?

BACKGROUND

Lipid disorders are known to be linked to disturbance in oxidative reactions and play an important role in the progression and complications of idiopathic nephrotic syndrome (INS).

AIMS

The aim of this study was to assess oxidized low-density lipoprotein (oxLDL), high-sensitive C-reactive protein (hs-CRP) serum concentrations and other parameters of lipid metabolism in children with INS during relapse and remission of proteinuria.

METHODS

The examination was performed on 23 children and adolescents diagnosed with INS. Reference group consisted of 22 participants. The study was carried out twice: in the relapse of INS (A) and in remission of proteinuria during glucocorticoid treatment (B).

RESULTS

OxLDL was higher in INS patients, in both examinations when compared with reference participants. hs-CRP showed no differences between nephrotic and healthy children. We found higher concentration of oxLDL in children, who where frequent relapsers. Cholesterol, triglycerides/high density lipoprotein cholesterol and platelets were higher in INS patients (both A and B) in comparison with healthy children.

CONCLUSIONS

We observed presence of pro-atherogenic lipid profile in INS. Elevation of oxLDL may reflect increased oxidative stress and higher risk of atherosclerosis in INS, therefore it seems to be relevant to find patients of risk of atherosclerosis to consider lipid lowering treatment with antioxidants.

Normal values for urine renalase excretion in children

BACKGROUND

The objective of this study was to establish age-dependent values for urinary renalase/creatinine (renalase/Cr) ratio in healthy children and adolescents.

METHODS

The study was conducted on a random sample of 157 healthy children and adolescents (0.1-17.9 years) divided into six age groups in 3-year intervals. Urine renalase concentration was measured using an enzyme-linked immunosorbent assay (ELISA) kit (Uscn Life Science, Wuhan, China).

RESULTS

We analyzed median urine renalase/Cr ratio in particular age groups with the use of analysis of variance (ANOVA). Renalase/Cr levels were significantly higher in the youngest children < 3 years in comparison with other age groups (4.07 ng/mg Cr, p < 0.05). There was a statistically significant negative correlation between urine renalase/Cr and body mass index (BMI) Z-score (r = -0.22, p < 0.05) and both systolic (r = -0.22, p < 0.05) and diastolic (r = -0.21, p < 0.05) blood pressure. We constructed the reference renalase/Cr percentiles according to age in 3-year intervals.

CONCLUSIONS

To the best of our knowledge, this study is the first to present reference values of urine renalase excretion in a healthy pediatric population. Further studies should concentrate on the influence of increased blood pressure or obesity on urine renalase excretion in children and teenagers.

Paediatric normative data for urine NGAL/creatinine ratio

AIM

The objective of this study was to establish age-dependent urine NGAL (neutrophil gelatinase-associated lipocalin)/creatinine ratio values in healthy children and adolescents.

METHODS

The study was performed using a random sample of 172 healthy children and adolescents (M-88, F-84), aged median 9.75 (0.2-17.9) years. Urine NGAL concentration was measured using a commercially available ELISA kit (R&D Systems, USA).

RESULTS

Median concentrations of urine NGAL/creatinine in particular age groups were analysed using anova. The differences between the youngest group of children under the age of 6 years and the rest of examined population were statistically significant. There were no differences in urine NGAL/creatinine between other age groups. Statistically significant negative correlation between urine NGAL/creatinine and age of subjects was found (r = -0.29, p < 0.05).

CONCLUSION

In the study, normative values of urine NGAL/creatinine for subjects aged 0.2-17.9 years have been established. These data may help clinicians and researchers to improve the interpretation of urine NGAL/creatinine ratio in children and adolescents. However, further studies using numerous data should be conducted to add reference values for urine NGAL partitioned by age and gender.

[WT1 mutation as a cause of progressive nephropathy in Frasier syndrome--case report]

Frasier syndrome is an uncommon genetic disorder featuring progressive glomerulopathy, male pseudohermaphroditism and gonadal dysgenesis. It is caused by mutations in intron 9 of the WT1 gene. Because of its rarity there is limited literature available on the diagnosis and treatment of this syndrome. The aim of the study was to present the clinicopathological findings and molecular analysis of phenotypically female adolescent presenting with severe proteinuria and primary amenorrhea. The significance of early recognition of Frasier syndrome and its differentiation from Denys-Drash syndrome was discussed. WT1 mutation analysis should be routinely done in females with steroid-resistant nephritic syndrome.

[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.