Clinical and genetic characterization of children with cubilin variants.

BACKGROUND: Cubilin is one of the receptor proteins responsible for reabsorption of albumin in proximal tubules and is encoded by the CUBN gene. We aimed to evaluate clinical and genetic characterization of six patients with proteinuria who had CUBN mutations. METHODS: Patients' characteristics, serum creatinine, albumin, vitamin B12 levels, urine analysis, spot urine protein/creatinine, microalbumin/creatinine, beta-2 microglobulin/creatinine ratios, estimated glomerular filtration rates (eGFR), treatments, kidney biopsies, and genetic analyses were evaluated. RESULTS: Six patients (2 female, 4 male) with an incidental finding of proteinuria were evaluated. Mean admission age and follow-up time were 7.3 ± 2.9 and 6.5 ± 5.6 years, respectively. Serum albumin, creatinine, and eGFR were normal; urine analysis revealed no hematuria, and C3, C4, ANA, and anti-DNA were negative; kidney ultrasonography was normal for all patients. Urine protein/creatinine was 0.9 ± 0.3 mg/mg, and microalbumin was high in all patients. Serum vitamin B12 was low in two patients and normal in four. Kidney biopsy was performed in four patients, three demonstrated normal light microscopy, and there was one focal segmental glomerulosclerosis (FSGS). Genetic tests revealed four homozygous and two compound heterozygous mutations in the C-terminal part of cubilin. All patients had normal eGFR and still had non-nephrotic range proteinuria at last visit. CONCLUSIONS: CUBN gene mutations should be considered in patients with isolated non-nephrotic range proteinuria and normal kidney function. Diagnosing these patients, who are thought to have a better prognosis, is important in terms of avoiding unnecessary treatment and predicting prognosis. CUBN gene mutations may also present as FSGS which extends the spectrum of renal manifestation of these patients. A higher resolution version of the Graphical abstract is available as Supplementary information.

Is hepcidin related with anemia and bone mineral metabolism in children with non-dialysis chronic kidney disease?

AIM: Functional iron deficiency seco ndary to inflammation and increased serum hepcidin lead to erythropoietin-resistant anemia in children with chronic kidney disease. Vitamin D deficiency, parathyroid hormone, and phosphate can also participate in chronic inflammation and anemia. The aim of this study was to evaluate the association between hepcidin, bone mineral metabolism, and anemia in non-dialysis pediatric patients with chronic kidney disease. MATERIAL AND METHODS: Thirty-five patients with stage 2-4 chronic kidney disease and 35 healthy subjects were enrolled in the study. Serum creatinine, blood urea nitrogen, uric acid, C-reactive protein, interleukin-6, hepcidin, complete blood count, ferritin, calcium, phosphorus, parathyroid hormone, 25-hydroxyvitamin D, 1,25-dihydroxyvitamin D, and fibroblast growth factor-23 levels were compared between the groups. RESULTS: Ferritin, C-reactive protein, interleukin-6, blood urea nitrogen, creatinine, uric acid levels, and percentages of reticulocytes were significantly higher than in the controls (p<0.05). The mean serum hepcidin levels in the chronic kidney disease and control groups were 9.6±5.2 (range, 2.15-25.3) and 9.7±4.3 (range, 3.4-22.2) ng/mL and were not significantly different in either group. There were no differences in terms of serum phosphorus, 25-hydroxyvitamin D, 1,25-dihydroxyvitamin D and fibroblast growth factor-23 levels between the groups (p>0.05). Serum hepcidin levels were not correlated with anemia parameters, serum fibroblast growth factor-23, phosphorus, uric acid, C-reactive protein, parathyroid hormone, and 25-hydroxyvitamin D levels (p>0.05). However, serum hepcidin levels were correlated with 1,25-dihydroxyvitamin D and interleukin-6 levels (p=0.013 and p=0.002, respectively). CONCLUSION: Serum hepcidin levels may not increase significantly in non-dialysis pediatric patients with chronic kidney disease despite high levels of inflammatory markers such as C-reactive protein and interleukin-6. The increase of serum hepcidin levels may be inhibited by effective treatment of anemia with iron supplementation and erythropoietin, and the treatment of secondary hyperparathyroidism with phosphate binders and the active form of vitamin D, which decrease serum parathyroid hormone and fibroblast growth factor-23 levels, and control inflammation to some extent.

Effects of nutritional vitamin D supplementation on markers of bone and mineral metabolism in children with chronic kidney disease.

Background: We investigated the effects of nutritional vitamin D supplementation on markers of bone and mineral metabolism, i.e. serum levels of fibroblast growth factor 23 (FGF23), Klotho, bone alkaline phosphatase (BAP) and sclerostin, in two cohorts with chronic kidney disease (CKD). Methods: In all, 80 vitamin D-deficient children were selected: 40 with mild to moderate CKD from the ERGO study, a randomized trial of ergocalciferol supplementation [estimated glomerular filtration rate (eGFR) 55 mL/min/1.73 m2], and 40 with advanced CKD from the observational Cardiovascular Comorbidity in Children with Chronic Kidney Disease (4C) study (eGFR 24 mL/min/1.73 m2). In each study, vitamin D supplementation was started in 20 children and 20 matched children not receiving vitamin D served as controls. Measures were taken at baseline and after a median period of 8 months. Age- and gender-related standard deviation scores (SDSs) were calculated. Results: Before vitamin D supplementation, children in the ERGO study had normal FGF23 (median 0.31 SDS) and BAP (-0.10 SDS) but decreased Klotho and sclerostin (-0.77 and -1.04 SDS, respectively), whereas 4C patients had increased FGF23 (3.87 SDS), BAP (0.78 SDS) and sclerostin (0.76 SDS) but normal Klotho (-0.27 SDS) levels. Vitamin D supplementation further increased FGF23 in 4C but not in ERGO patients. Serum Klotho and sclerostin normalized with vitamin D supplementation in ERGO but remained unchanged in 4C patients. BAP levels were unchanged in all patients. In the total cohort, significant effects of vitamin D supplementation were noted for Klotho at eGFR 40-70 mL/min/1.73 m2. Conclusions: Vitamin D supplementation normalized Klotho and sclerostin in children with mild to moderate CKD but further increased FGF23 in advanced CKD.

Changes in Bacterial Resistance Patterns of Pediatric Urinary Tract Infections and Rationale for Empirical Antibiotic Therapy.

BACKGROUND: The causative agent spectrum and resistance patterns of urinary tract infections in children are affected by many factors. AIMS: To demonstrate antibiotic resistance in urinary tract infections and changing ratio in antibiotic resistance by years. STUDY DESIGN: Retrospective cross-sectional study. METHODS: We analysed antibiotic resistance patterns of isolated Gram (-) bacteria during the years 2011-2014 (study period 2) in children with urinary tract infections. We compared these findings with data collected in the same centre in 2001-2003 (study period 1). RESULTS: Four hundred and sixty-five uncomplicated community-acquired Gram (-) urinary tract infections were analysed from 2001-2003 and 400 from 2011-2014. Sixty-one percent of patients were female (1.5 girls : 1 boy). The mean age of children included in the study was 3 years and 9 months. Escherichia coli was the predominant bacteria isolated during both periods of the study (60% in study period 1 and 73% in study period 2). Bacteria other than E. coli demonstrated a higher level of resistance to all of the antimicrobials except trimethoprim-sulfamethoxazole than E. coli bacteria during the years 2011-2014. In our study, we found increasing resistance trends of urinary pathogens for cefixime (from 1% to 15%, p<0.05), amikacin (from 0% to 4%, p<0.05) and ciprofloxacin (from 0% to 3%, p<0.05) between the two periods. Urinary pathogens showed a decreasing trend for nitrofurantoin (from 17% to 7%, p=0.0001). No significant trends were detected for ampicillin (from 69% to 71%), amoxicillin-clavulanate (from 44% to 43%), cefazolin (from 39% to 32%), trimethoprim-sulfamethoxazole (from 32% to 31%), cefuroxime (from 21% to 18%) and ceftriaxone (from 10% to 14%) between the two periods (p>0.05). CONCLUSION: In childhood urinary tract infections, antibiotic resistance should be evaluated periodically and empiric antimicrobial therapy should be decided according to antibiotic sensitivity results.

Intravesical hyaluronic acid treatment improves bacterial cystitis and reduces cystitis-induced hypercontractility in rats.

OBJECTIVE: To investigate the effect of intravesical hyaluronic acid on Escherichia coli-induced cystitis and cystitis-induced hypercontractility in rats. METHODS: Bacterial cystitis was induced in Wistar female rats by intravesical inoculation of E. coli. Isotonic saline was instilled in the control group (n = 6). The rats were either non-treated, treated with gentamycin (4 mg/kg, 5 days) or treated intravesically with hyaluronic acid (0.5 mL, 0.5%). On the eighth day, the bladder tissues were excised for histological examination, and the measurements of myeloperoxidase, superoxide dismutase and catalase activities. Contraction/relaxation responses to carbachol, isoprotrenol and papaverine were studied. RESULTS: Tissue myeloperoxidase activity was increased, but superoxide dismutase and catalase activities were decreased in bacterial cystitis, while hyaluronic acid treatment reversed these changes. In the hyaluronic acid-treated group, healing of the uroepithelium was observed, while decreased inflammatory cell infiltration was obvious in gentamycin-treated group. E. coli-induced cystitis in all rats resulted in increased contraction responses to carbachol compared with controls (P < 0.01). Treatment with hyaluronic acid, but not gentamycin, significantly (P < 0.05) depressed hypercontractility at maximum carbachol concentrations. In all rats with cystitis, papaverine-induced relaxation was increased, whereas isoproterenol-induced relaxation curves were not different between the studied groups. CONCLUSION: Gentamycin treatment, despite its ameliorative effect on inflammation, had no impact on the contractile dysfunction of the injured bladder. Intravesical hyaluronic acid, in addition to its supportive role in the healing of the epithelium, seems to lower the increased threshold for contraction and to reduce oxidative stress. These findings support a potential role for hyaluronic acid in the treatment of bacterial cystitis.

Are myelodysplastic children receiving sufficient health care in Turkey? An analysis of the problems in primary management and their impact on neuro-urological outcome.

OBJECTIVE: To investigate the problems in the primary care of children with spina bifida and to analyze their impact on neuro-urological outcome in Turkey. Information from mothers about the disease, difficulties in getting medical services, availability and efficacy of prenatal ultrasound, and folic acid intake was also assessed. PATIENTS: A retrospective review of 476 children registered in the pediatric urology section of our institutional multidisciplinary spina bifida clinic between 1996 and 2005 was made. All children were assessed for the time of primary repair, time to first neuro-urological visit, and compliance to follow up. A phone interview was made with 166 mothers to obtain data regarding their educational status, supplementary folic acid intake before/during gestation, compliance to obstetric follow up, prenatal diagnosis and counseling, information about the importance of neuro-urological surveillance, and difficulties in neuro-urological follow up. RESULTS: Two-thirds of the mothers had an educational status of elementary school or lower. Phone interviews revealed inadequate obstetric follow up in 42% and a low prenatal diagnosis rate (49%) in those under regular follow up. Chart review revealed a significant delay in timing of primary surgical closure (mean 3 months and 2.9 years for open and closed lesions, respectively) and first neuro-urological follow-up visit (mean 1.8 years and 9.7 months after primary repair for open and occult lesions, respectively). Reasons for delayed closure were misguided advice of the nurse/midwife involved in delivery and inability to obtain tertiary health care. Socioeconomic inadequacy of the families and inefficacy of the health insurance system were the most important factors impairing follow up. CONCLUSIONS: Serious problems exist in the prevention, prenatal diagnosis and primary management of children with myelodysplasia in Turkey. As a consequence, neuro-urological follow up starts relatively late, which adversely affects the urological prognosis.