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Background: The pathophysiological mechanisms crucial in the development of nephrotic syndrome (NS) in the pediatric population are still not fully understood. This study aimed to investigate the relationship between hypertension, oxidative stress, and inflammation in pediatric patients during the acute phase of the disease. Methods: The study included 33 children, aged 2 to 9 years, with nephrotic syndrome. Blood samples were collected during the acute phase and remission. Parameters of oxidative status were determined, including total oxidative status (TOS), advanced oxidation protein products (AOPP), prooxidant-antioxidant balance (PAB), sulfhydryl groups (-SH), paraoxonase 1 (PON1), and total antioxidant status (TAS) in serum, measured spectrophotometrically. Inflam - matory parameters such as pentraxin 3 (PTX3), leptin, program med cell death ligand 1 (PD-L1), and E-cadherin were determined using enzyme-linked immunosorbent assay (ELISA). Results: Patients with nephrotic syndrome and hypertension had significantly higher levels of advanced oxidation protein products and total antioxidant status (p=0.029 and p=0.003, respectively). During the acute phase of the disease, lower activity of sulfhydryl groups and paraoxonase 1 was observed compared to remission (p

Introduction. Recently, inactivation mutations of CYP24A1, the gene encoding vitamin D 24-hydroxylase, were identified in hypercalciuric nephrolithiasis and nephrocalcinosis. Here, we describe а long-term follow-up of a patient with hypercalciuric nephrolithiasis caused by CYP24A1 mutations. Case outline. A male Montenegro patient first presented with microhematuria at the age of five years. Hypercalciuria had been documented and for some time he had been treated by hydrochlorothiazide. After 12 years, the patient presented with macrohematuria and left-sided nephrolithiasis. He was found to have intermittent borderline hypercalcemia, suppressed parathyroid hormone, hypercalciuria, and increased plasma 25-hydroxy vitamin D [25(OH)D3]. The patient denied any vitamin D supplementation and all other causes of hypercalcemia were ruled out. Positive family history for nephrolithiasis (both parents and grandmother) and similar biochemical abnormalities detected in father and son pointed to an inherited disorder. A homozygous mutation in CYP24A1 (E143del) was found in the patient and his father, while mother is heterozygous. During the follow-up of two years, the patient underwent four extracorporeal shockwave lithotripsies, he was advised to increase water intake, and to avoid sunlight exposure. At the end of follow-up he was asymptomatic, and his renal ultrasound was normal, as well as his renal function, but hypercalciuria and low parathyroid hormone levels persisted. Conclusion. Hypervitaminosis D should be considered in children with idiopathic hypercalciuria, nephrolithiasis and nephrocalcinosis of unknown etiology. Recognition of CYP24A1 mutations in these patients may help to decrease the serious consequences by avoiding vitamin D supplements and excessive sun exposure. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. 175079]

Introduction/Objective. Jeune syndrome (JS) is a rare hereditary ciliopathy characterized by asphyxiating thoracic dystrophy, shortened limbs and brachydactyly. Extraskeletal anomalies such as chronic renal failure (CRF), hepatic fibrosis, and retinitis pigmentosa may be a part of the JATD phenotype. The aim of this study is to present long-term follow-up of JS patients with early progressive kidney disease. Methods. This is a retrospective study of pediatric patients with JS and CRF who were treated at the University Children’s Hospital between January 1980 and December 2014. The patients’ data were retrospectively reviewed from the medical records. Results. There were thirteen patients from 11 families, five girls and eight boys mean aged 4.3 years at the time of diagnosis. All of the patients had characteristic skeletal findings, retinal degeneration and an early onset of CRF at age range from 1.5 to 7 years. Five patients had neonatal respiratory distress and congenital liver fibrosis was diagnosed in five patients. One patient died due to complications of CRF, while others survived during follow-up of mean 11 years. IFT140 mutations were found in four genetically tested patients. Conclusion. The average incidence rate of JS with renal phenotype in Serbia was about 0.2 per one million of child population. Long-term survival of JS patients depends on renal replacement therapy, while skeletal dysplasia, growth failure, respiratory and eyes problems have impact on the patients’ quality of life.

Introduction. Congenital nephrotic syndrome (CNF) is manifested at birth or within the first three months of life. The Finnish-type of CNF is caused by the mutation of the NPHS1 gene, which encodes nephrin in the podocyte slit diaphragm. It is a very severe disease, for which immunosuppressive therapy is not advised. Here we describe a patient with CNF who responded to CsA by partial remission. Case outline. A girl aged 2.5 months presented with severe non-syndromic steroid-resistant nephrotic syndrome. She needed aggressive support including daily albumin infusions and diuretics. Substitution of vitamin D, thyroxin, and anticoagulants were regularly administered. She was also treated with angiotensin converting enzyme inhibitor, without clear benefits regarding proteinuria. In addition, she received intravenous gamma-globulin replacement therapy and antibiotics during frequent infections. While waiting for the results of genetic analyses and faced with many problems related to daily albumin infusions, infections, and thromboembolic complications, cyclosporine A (CsA) was introduced as an alternative to early nephrectomy and consequent renal failure. The patient responded by partial remission and CsA treatment continued at home without the albumin infusions. After almost five years since the beginning of the treatment, the patient’s renal function remains unreduced. Conclusion. Our case demonstrates that CsA can induce partial remission in patients with genetic forms of steroid-resistant nephrotic syndrome without influencing the glomerular filtration rate. However, its long-term effect and safety should carefully be monitored. [Project of the Ministry of Education, Science and Technological Development of Republic of Serbia, Grant No. 175079]

Introduction. The causes of acute tubulointerstitial nephritis can be grouped into four broad categories: medications, infections, immunologic diseases, or idiopathic processes. Here we report a 17-year-old female who developed acute kidney injury (AKI) due to granulomatous interstitial nephritis (GIN) associated with influenza A: H1N1 infection. Case Outline. The illness presented after two weeks of respiratory tract infection, skin rash and hypermenorrhea. On admission the patient was febrile, with bilateral pedal edema, macular skin rash, and auscultatory finding that suggested pneumonia. Laboratory investigations showed normocytic anemia, azotemia, hematuria and proteinuria. Renal ultrasound was normal. Antinuclear antibodies, antineutrophil cytoplasmic antibodies, lupus anticoagulant, antiphospholipid antibodies were negative with normal complement. Urine cultures including analysis for Mycobacterium tuberculosis were negative. The diagnosis of influenza A: H1N1 infection was made by positive serology. A kidney biopsy showed interstitial nephritis with peritubular granulomas. Glomeruli were normal. Staining for immunoglobulins A, M, G, and E was negative. The girl was treated with oseltamivir phosphate (Tamiflu; Genentech, Inc., South San Francisco, CA, USA) for five days, as well as with tapered prednisone after a starting dose of 2 mg/kg. The treatment resulted in a complete remission during two years of follow-up. Conclusion. We present a severe but reversible case of GIN and AKI associated with influenza A: H1N1 infection. Although a causal effect cannot be confirmed, this case suggests that influenza A: H1N1 should be considered in the differential diagnosis of GIN manifested with AKI in children. [Projekat Ministarstva nauke Republike Srbije, br. 175079]

A normal development of lower urinary tract function control evolves from involuntary bladder empting (incontinence) during infancy to daytime urinary continence, and finally a successful day and night continence that is generally achieved by the 5th to 7th year of age. This gradual process primarily depends on the progressive maturation of the neural control of the lower urinary tract, but it is also influenced by behavioral training that evolves through social support. Functional voiding disorders (bladder dysfunction) are common problems during childhood. They are present in 5-15 % of general pediatric population, and in one-fifth of school-age children or in over one-third of patients of the pediatric urologist or nephrologist. More than half of children with bladder dysfunction have vesicoureteral reflux, and more than two-thirds have recurrent urinary tract infections. There is also a frequent association of bladder dysfunction with constipation and encopresis (dysfunctional elimination syndrome). Bladder dysfunction may cause a permanent damage to the upper urinary tract and kidneys. In addition, urinary incontinence, as the most common manifestation of bladder dysfunction can be the cause of major stress in schoolage children and have a negative effect on the child’s feeling of self-esteem. Thus, a timely detection and treatment of this group of disorders in children is highly significant.

Introduction: Childhood obesity is related to cardiovascular diseases and diabetes mellitus type 2 in later life. Resistin, an adipokine primarily secreted by monocytes and tissue macrophages in humans, is considered to be associated with these conditions. The Aim: To examine the correlations between resistin concentration and anthropometric parameters, lipid status, inflammatory markers and parameters of insulin resistance in obese children and adolescents. Material and Methods: The study included 66 patients (40 boys, 26 girls), which underwent anthropometric measuring and laboratory testing (glucose level, total cholesterol, high-density lipoprotein cholesterol (HDL-cholesterol), low-density lipoprotein cholesterol (LDL-cholesterol), triglycerides, uric acid, high-sensitivity C-reactive protein (hsCRP) and glycosylated hemoglobin (HbA1c). Insulin resistance was estimated with HOMA-IR (homeostasis model assessment of insulin resistance). Results: We determined that 63.3% of our patients had dyslipidemia, while hsCRP and uric acid levels suggested an ongoing inflammation. We established that there was a correlation between resistin concentration and waist to hip ratio (WHR) (r=0.294, p

Introduction. Post-transplant lymphoproliferative disorder (PTLD) is a heterogeneous group of diseases, characterized by abnormal lymphoid proliferation following transplantation. It is a disease of the immunosuppressed state, and its occurrence is mostly associated with the use of T-cell depleting agents, and also intensification of immunosuppressive regimens. In the majority of cases, PTLD is a consequence of Epstein-Barr virus (EBV) infection and is a B-cell hyperplasia with CD-20 positive lymphocytes. The 2008 World Health Organization classification for lymphoid malignancies divides PTLD into four major categories: early lesions, polymorphic PTLD, monomorphic PTLD and Hodgkin PTLD. The treatment and prognosis depend on histology. The cornerstone of PTLD therapy includes reduction/withdrawal of immunosuppression, monoclonal anti CD-20 antibody (rituximab) and chemotherapy. Outline of Cases. We reported here our experiences with three patients, two girls aged 7.5 and 15 and a 16-year old boy. They had different organ involvement: brain, combined spleen-liver and intestines, respectively. Even though EBV was a trigger of lymphoid proliferation as it was confirmed by histopathology or in cerebrospinal fluid, qualitative EBV-PCR was positive only in one patient at disease presentation. Reduction of immunosuppression therapy was applied in treatment of all three patients, while two of them received rituximab and ganciclovir. They had an excellent outcome besides many difficulties in diagnosis and management of disease. Conclusion. Qualitative EBV-PCR is not useful marker in pediatric transplant recipients. Our suggestion is that patients with the risk factors like T-cell depleting agents, immunosuppressant protocol or increasing immunosuppressive therapy and EBV miss-match with donor must be more accurately monitored with quantitative EBV PCR. [Projekat Ministarstva nauke Republike Srbije, br. 175085]

Introduction. Frasier syndrome (FS) is a genetic form of glomerulopathy, which results from mutations in the Wilms’ tumour suppressor gene (WT1). Proteinuria in FS has been traditionally considered unresponsive to any medication and FS inevitably progresses to end stage renal failure. Case Outline. We present a patient with FS who had atypical clinical manifestation and unusual beneficial antiproteinuric response to renin-angiotensin system (RAS) inhibitors given in combination with indomethacin. After 13 years of follow-up, the patient is now 17-year old with normal renal functions and no proteinuria. Conclusion. RAS inhibitors combined with indomethacin showed beneficial effect in our patient. Thus, this combination might be the initial treatment of patients with FS. If this treatment strategy was not satisfied for at least 3 months, then CsA would be considered to be administered taking account of the nephrotoxicity and the increased risk of malignancy. Further prospective study is required to clarify this issue. [Projekat Ministarstva nauke Republike Srbije, br. OI175079]

Introduction. Urinary tract infection is common in childhood. Depending on the localization of the infection, severity of its clinical presentation and possible acute and long-term complications, it may be described as either acute cystitis or acute pyelonephritis. Objective. The aim of this study was to assess the resistance patterns of uropathogens during the last 5 years in newborns and young children with acute pyelonephritis. Methods. Uropathogens resistance to commonly usable anti-microbial agents (ampicillin, a combination of sulphamethoxasole and trimethoprim, cephalexin, ceftriaxone, cefotaxime, ceftazidime, gentamycin, amikacin, ciprofloxacin, imipenem and nalidixic acid) was retrospectively studied in newborns and young children treated during early (2005-2007) and late (2008-2009) study periods. Anti-bacterial susceptibility testing of the urine isolates was performed by the standard disc diffusion method. Results. 117 newborns and 294 children aged 9.3±0.7 months were treated during early (n=136) or late (n=275) study period due to the first episode of acute pyelonephritis. Escherichia coli was the most common bacterial pathogen (85.5%). Compared to children older than one month, newborns had higher degree of antibacterial resistance to 2nd and 3rd generation cephalosporins, aminoglycosides, and nalidixic acid during early, and to ceftazidime, aminoglycosides and nalidixic acid during late study period. Also, multidrug resistance was more common in newborns during the early study period. Conclusion. Newborns had higher rate of antibacterial resistance than young children. The progressive increase of anti-microbial resistance in children with acute pyelonephritis is of great concern.

Introduction. The choice of empiric therapy of acute pyelonephritis (APN) in children should be based on the knowledge of Escherichia coli (E. coli) as the most common uropathogen and its antibiotic sensitivities considering that nowadays ESBL-producing [ESBL (+)] E. coli is on the rise worldwide. Objective. To examine in vivo susceptibility of ESBL (+) E. coli to ceftriaxone (CTX), and to evaluate the options for empiric therapy for APN in children. Methods. Retrospective study of CTX empiric therapy of APN in children treated at the University Children΄s Hospital in Belgrade from January 2005 to December 2009. ESBL phenotypic confirmatory test with ceftazidime, CTX and cefotaxime was performed for all urine isolates by disc diffusion method on Mueller-Hinton agar plates. In vivo sensitivity of CTX documented by clinical response to empiric CTX therapy was compared between two groups of children: group I with ESBL (+) E. coli and group II with ESBL (-) E. coli APN. Results. Group I with ESBL (+) APN consisted of 94 patients and group II of 120 patients with ESBL (-) APN, respectively. All patients received CTX as empiric therapy at a mean dose of 66.9 mg during 7.2±2.6 days of therapy. Clinical effect of CTX was similar in patients with ESBL (+) compared to those with ESBL (-) APN. Conclusions. In vitro resistance of ESBL E. coli to CTX determined by standard methods is not sufficiently predictive for its in vivo sensitivity. Therefore CTX may be used as empiric therapy for acute pyelonephritis in children.

Introduction. Henoch-Schönlein purpura (HSP) is the most common vasculitis of childhood. It is characterized by symptoms including nonthrombocytopenic purpura, abdominal pain, haematuria/proteinuria, and arthralgia/arthritis. The pleiomorphism of clinical signs in HSP could be confused with other conditions or other vasculitis forms. Objective. Evaluation of HSP clinical presentation, the onset and severity of renal manifestation in affected children and their outcome. Methods. A retrospective study of 49 patients diagnosed with HSP was conducted from September 1999 to September 2009. Children with severe renal manifestations (nephrotic range proteinuria, with or without nephrotic or nephritic syndrome) have undergone kidney biopsy. Results. Twenty-five patients developed renal manifestations after onset of the disease. In our study child’s older age was a risk factor for association with HSP nephritis. Six of the patients required kidney biopsy. They were successfully treated with various immunosuppressive protocols, as well as three of nine patients with nephrotic range proteinuria. Two patients developed most severe form of HSP nephritis, nephrotic-nephritic syndrome with histology grade IIIb/IVb. During the study period (average follow-up 6 years), all patients had a normal global renal function with mild proteinuria in only two cases. The prognosis of renal involvement was better than reports from other patient series. Conclusion. Long-term morbidity of HSP is predominantly attributed to renal involvement. During the study period, no patient had renal insufficiency or end stage renal disease after various combinations of immunosuppressive treatment. It is recommended that patients with HSP nephritis are followed for longer periods of time with a regular measurement of renal function and proteinuria.

Introduction Familial hypomagnesaemia with hypercalciuria and nephrocalcinosis (FHHNC) is a rare autosomal recessive disease characterized by excessive renal magnesium and calcium wasting, bilateral nehrocalcinosis and progressive renal failure. This is the first report of FHHNC of four patients in Serbia. Outline of Cases The first three patients were siblings from the same family. The index case, a 9-yearold girl, presented with severe growth retardation, polyuria and polydipsia, while her brothers, 11 and 7 years old, were disclosed during family member screening. The father had a urolithiasis when aged 18 years, while intermittent microhaematuria and bilateral microlithiasis persisted later on. The fourth patient, a 16-year-old boy with sporadic FHHNC was discovered to have increased proteinuria at routine examination of urine before registration for secondary school. He was well grown up, normotensive, but had moderate renal failure (CKD 3 stage), mild hypomagnesaemia and severe hypercalciuria and nephrocalcinosis. Beside typical clinical and biochemical data, the diagnosis of FHHNC was confirmed by mutation analysis of the CLDN16 gene; in all four affected individuals a homozygous CLDN16 mutation (Leu151Phe) was found. Treatment with magnesium supplementation resulted in the normalization of serum magnesium levels only in one patient (patient 4), but hypercalciuria persisted and renal failure progressed in all patients. Conclusion FHHNC is a rare cause of chronic renal failure. The first four patients with FHHNC in Serbia have been here described. The diagnosis of FHNNC based on the findings of nephrocalcinosis with hypomagnesiaemia and hypercalciuria, was confirmed by homozygous paracellin1-mutation exhibiting a Leu151Phe. .

Introduction. Growth retardation is a hallmark of chronic illnesses such as chronic kidney disease in children, and it is associated with increased morbidity and mortality. The growth hormone (GH) resistance observed in uraemia can be overcome by supraphysiological doses of exogenous GH. Objective. We would like to present our first results of recombinant human growth hormone (rhGH) treatment, mainly in children on haemodialysis. Methods. Sixteen children, aged 4.5-17.1 years (mean age 11.25±3.57) with height below -2.0 standard deviation score (SDS) for age or height velocity below -2.0 SDS for age, were selected to receive rhGH therapy at our Nephrology and Haemodialysis Department. Most of them were on haemodialysis (14 children) with mean spent time 2.88±2.68 years (0-9 years) before the initiation of rhGH therapy. One half of patients were prepubertal (8 children) and the second half were in early puberty (testicular volume between 4 and 8 ml for boys and breast development B2 or B3 in girls). All patients received 28-30IU/m² rhGH per week by daily subcutaneous injection. The year before rhGH therapy served as a control period. Results. During the first year of treatment, mean height velocity in haemodialysis patients increased from 2.25 cm/year to 6.59 cm/year (p

Background/aim: Juvenile obesity is associated with several metabolic abnormalities, one of them being atherogenic dyslipidemia. Suboptimal fetal growth is associated with obesity risk in childhood, but also with increased rate of metabolic diseases in later life. This study investigated associations of neonatal data (Apgar score, birth weight and birth length) with low-density lipoprotein and high-density lipoprotein (LDL and HDL) subclasses in a group of obese children, as well as a possible impact of breastfeeding duration on obesity-associated lipoprotein subclasses distributions.Materials and methods: We included 42 obese children, aged 14.2 ± 2.1 years. LDL and HDL subfractions were separated by gradient gel electrophoresis and biochemical parameters were assessed by routine methods.Results: Compared with obese children with Apgar ≥ 9, the group with Apgar < 9 had significantly higher percentages of small, dense LDL particles (P < 0.05), due to reduced LDL I (P < 0.01) and increased LDL III subclasses (P < 0.05). Birth weight was positively associated with the proportions of LDL I particles (P < 0.001), whereas birth height positively correlated with the amount of HDL 2b subclasses (P < 0.05). The group of never or less than 3 months breastfed children had significantly smaller LDL size (P < 0.01) and lower proportion of HDL 2a particles (P < 0.05) than their ≥3 months breastfed peers.Conclusion: The results showed significant associations of neonatal characteristics with LDL and HDL particle distributions in obese children. In addition, our results point toward positive aspects of longer breastfeeding duration on lipoprotein particle distributions in obese children.