Urine soluble TLR4 levels may contribute to predict urinary tract infection in children: the UTILISE Study.

BACKGROUND: One of the most common bacterial infections in childhood is urinary tract infection (UTI). Toll-like receptors (TLRs) contribute to immune response against UTI recognizing specific pathogenic agents. Our aim was to determine whether soluble TLR4 (sTLR4), soluble TLR5 (sTLR5) and interleukin 8 (IL-8) can be used as biomarkers to diagnose UTI. We also aimed to reveal the relationship between urine Heat Shock Protein 70 (uHSP70) and those biomarkers investigated in this study. METHODS: A total of 802 children from 37 centers participated in the study. The participants (n = 282) who did not meet the inclusion criteria were excluded from the study. The remaining 520 children, including 191 patients with UTI, 178 patients with non-UTI infections, 50 children with contaminated urine samples, 26 participants with asymptomatic bacteriuria and 75 healthy controls were included in the study. Urine and serum levels of sTLR4, sTLR5 and IL-8 were measured at presentation in all patients and after antibiotic treatment in patients with UTI. RESULTS: Urine sTLR4 was higher in the UTI group than in the other groups. UTI may be predicted using 1.28 ng/mL as cut-off for urine sTLR4 with 68% sensitivity and 65% specificity (AUC = 0.682). In the UTI group, urine sTLR4 levels were significantly higher in pyelonephritis than in cystitis (p < 0.0001). Post-treatment urine sTLR4 levels in the UTI group were significantly lower than pre-treatment values (p < 0.0001). CONCLUSIONS: Urine sTLR4 may be used as a useful biomarker in predicting UTI and subsequent pyelonephritis in children with UTI. A higher resolution version of the Graphical abstract is available as Supplementary information.

The Clinical and Mutational Spectrum of Turkish Patients with Cystinosis.

BACKGROUND AND OBJECTIVES: Infantile nephropathic cystinosis is a severe disease that occurs due to mutations in the cystinosis gene, and it is characterized by progressive dysfunction of multiple organs; >100 cystinosis gene mutations have been identified in multiple populations. Our study aimed to identify the clinical characteristics and spectrum of cystinosis gene mutations in Turkish pediatric patients with cystinosis. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: We identified the clinical characteristics and spectrum of cystinosis gene mutations in Turkish patients with cystinosis in a multicenter registry that was established for data collection. The data were extracted from this registry and analyzed. RESULTS: In total, 136 patients (75 men and 61 women) were enrolled in the study. The most common clinical findings were growth retardation, polyuria, and loss of appetite. None of the patients had the 57-kb deletion, but seven novel mutations were identified. The most common mutations identified were c.681G>A (p.Glu227Glu; 31%), c.1015G>A (p.Gly339Arg; 22%), and c.18_21 del (p.Thr7Phefs*7; 14%). These mutations were associated with earlier age of disease onset than the other mutations. To understand the effects of these allelic variants on clinical progression, the mutations were categorized into two major groups (missense versus deletion/duplication/splice site). Although patients with missense mutations had a better eGFR at the last follow-up visit, the difference was not significant. Patients in whom treatment began at age <2 years old had later onset of ESRD (P=0.02). Time to ESRD did not differ between the patients with group 1 and group 2 mutations. CONCLUSIONS: The most common cystinosis gene mutations identified in Turkey were c.681G>A (p.Glu227Glu), c.1015G>A (p.Gly339Arg), and c.18_21 del (p.Thr7Phefs*7). Patients with less severe cystinosis gene mutations tend to have better kidney outcome.

Urinary Netrin-1: A New Biomarker for the Early Diagnosis of Renal Damage in Obese Children.

OBJECTIVE: Urinary netrin-1 is a new marker to demonstrate early tubular damage. The aim of this study was to determine whether urinary netrin-1 is increased in obese children. METHODS: A total of 68 normoalbuminuric and normotensive obese patients and 65 controls were included in the study. Urine samples were collected for assessment of urinary phosphorus, sodium, potassium, creatinine, albumin, and netrin-1. Blood samples were collected for measurements of fasting glucose, insulin, lipid, phosphorus, sodium, potassium, and creatinine levels. Homeostatic model assessment insulin resistance index was calculated. RESULTS: Gender and age were similar between obese and control groups (12.01±3.03 vs. 11.7±3.2 years, p=0.568 and 33 vs. 35 girls, p=0.543, respectively). Obese patients had significantly higher netrin-1 excretion than the controls (841.68±673.17 vs. 228.94±137.25 pg/mg creatinine, p=0.000). Urinary netrin-1 level was significantly higher in obese subjects with insulin resistance compared to those without insulin resistance (1142±1181 vs. 604.9±589.91 pg/mg creatinine, p=0.001). CONCLUSION: In normotensive and normoalbuminuric obese children, urinary netrin-1 level can increase before onset of albuminuria. Urinary netrin-1 excretion appears to be affected predominantly by insulin resistance and hyperinsulinemia. Urinary netrin-1 may be a new biomarker for determining early tubular injury in obese children.

Long-term results of children diagnosed with idiopathic nephrotic syndrome; single center experience.

AIM: The aim of this study was to determine the long-term results of children followed up with a diagnosis of nephrotic syndrome in a single center. MATERIALS AND METHOD: The medical data of 33 patients aged between 6 months and 10 years who were diagnosed with idiopathic nephrotic syndrome in our center between January 2000 and December 2012 and followed up for a period of 2-12 years were reviewed (Gulhane Military Medical Academy Ethics committee, 07.11.2012/10). RESULTS: The mean age of disease onset was 3.2±2.04 years (range: 0.5-10 years) and the mean follow-up period was 6±3.4 years (range: 2-12 years). Thirteen (39.4%) of the study group (or the patients) were female and 20 (60.6%) were male. Twenty seven (1.8%) of the patients were sensitive to steroid and 6 (18.1%) were resistant to steroid. Four (12.1%) of the steroid-resistant patients had steroid-dependent nephrotic syndrome, 5 (15.2%) had frequently relapsing nephrotic syndrome and 18 (54.5%) had rarely relapsing nephrotic syndrome. Histopathological diagnoses of six patients who underwent biopsy because of resistance to steroid were as follows: focal segmental glomerulosclerosis (n=3), C1q nephropathy (n=1), diffuse mesangial proliferation (n=1) and membraneous nephropathy (n=1). Fifteen (45.5%) patients entered into full remission and 2 (6%) patients developed chronic renal failure. Treatment complications including decreased bone mineral density in three patients (9%), short stature in 2 patients (6%) and cataract in 2 patients (6%) developed. CONCLUSIONS: Children with nephrotic syndrome carry a risk in terms of short stature, osteoporosis, cataract and renal failure in the long-term follow-up. It was observed that our rates of response to steroid were similar to the literature and the most common histopathological diagnosis was focal segmental glomerulosclerosis in our patients who underwent biopsy because of resistance to steroid. It was thought that multi-center studies should be conducted to demonstrate regional or national differences related with long-term results of childhood nephrotic syndrome.

Malondialdehyde, antioxidant enzymes, and renal tubular functions in children with iron deficiency or iron-deficiency anemia.

We aimed to investigate the effects of iron deficiency (ID) or iron-deficiency anemia (IDA) on oxidative stress and renal tubular functions before and after treatment of children. A total of 30 children with a diagnosis of IDA constituted the IDA group and 32 children with a diagnosis of ID constituted the ID group. Control group consisted 38 age-matched children. Serum ferritin, soluble transferrin receptor (sTfR), serum, and urinary sodium (Na), potassium (K), calcium (Ca), phosphorus (P), creatinine (Cr), uric acid (UA), urinary N-acetyl-ß-D-glucosaminidase (NAG) levels, and intra-erythrocyte malondialdehyde (MDA), catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px) levels were measured before and after iron therapy in the IDA and ID groups, whereas it was studied once in the control group. We have divided the study group in groups according to age (infants <2 years, children 3-9 years, and adolescents 10-15 years). Patients with IDA (infant, adolescent) and ID (infant, children, and adolescent) had a significantly high level of MDA in post-treatment period in comparison to those of healthy control. Patients with IDA (children, adolescent) and ID (infant, children) had a significantly high level of pre-treatment GSH-Px than controls. Post-treatment SOD was lower in IDA (children and adolescent) groups than control and post-treatment CAT was lower in IDA and ID (adolescent) groups than control. These findings show that ferrous sulfate used in the treatment of ID or IDA could lead to oxidative stress; however, a marked deterioration of in proximal renal tubular functions was not seen.

Evaluation of lipid peroxidation and antioxidant system in healthy iron-replete infants receiving iron prophylaxis.

OBJECTIVE: Iron supplementation is commonly recommended for infants; however, there are some reports that it causes oxidative damage. The aim of this study was to investigate the potential effects of iron supplementation at 4 mo of age, for a period of 2 mo, on lipid peroxidation and free radical scavenging enzymes. METHODS: Twenty-seven healthy 4-mo-old infants chosen randomly and given iron supplementation (ferrous sulfate, 10 mg of elemental iron per day) constituted the study group and 26 healthy 4-mo-old infants who were chosen randomly and not given iron supplementation constituted the control group. Weight, height, head circumference, complete blood cell count, serum ferritin level and intraerythrocytic zinc, iron, copper, malondialdehyde, catalase, superoxide dismutase, and glutathione peroxidase levels were measured in the two groups at 4 and 6 mo of life. RESULTS: Compared with controls at 6 mo of age, no significant differences were observed for intraerythrocytic zinc (0.5 ± 0.1 versus 0.6 ± 0.2 µg/mL, P > 0.05), copper (0.2 ± 0.1 versus 0.2 ± 0.2 µg/mL, P > 0.05), iron (130.8 ± 10.9 versus 127.4 ± 11.1 µg/mL, P > 0.05), malondialdehyde (21.4 ± 3.5 versus 22.4 ± 2.3 nmol/g of hemoglobin, P > 0.05), catalase (135.4 ± 23.9 versus 135.1 ± 23.3 MU/g of hemoglobin, P > 0.05), superoxide dismutase (1736.4 ± 141.1 versus 1701.3 ± 103.9 U/g of hemoglobin, P > 0.05), and glutathione peroxidase (8.9 ± 1.6 versus 8.4 ± 1.6 U/g of hemoglobin, P > 0.05) levels. CONCLUSION: Our study indicates that the supplemental use of elemental iron 10 mg/d for a period of 2 mo in healthy iron-replete infants did not cause lipid peroxidation or an impairment of antioxidant status.