Superiority of Cystatin C over Creatinine for Early Diagnosis of Acute Kidney Injury in Pediatric Acute Lymphoblastic Leukemia/Lymphoblastic Lymphoma.

The exact incidence of acute kidney injury (AKI) during chemotherapy for acute lymphoblastic leukemia (ALL)/lymphoblastic lymphoma (LBL) is unknown. Furthermore, childhood cancer survivors are at risk of AKI-chronic kidney disease transition. Thus, early diagnosis of AKI is crucial. This study aimed to elucidate the incidence of AKI in patients undergoing chemotherapy for pediatric ALL/LBL and to compare the usefulness of serum cystatin C (CysC)- and creatinine (Cr)-based estimated glomerular filtration rate (eGFR) as diagnostic measures. Data of 16 patients with ALL/LBL treated with a total of 75 courses of chemotherapy were retrospectively analyzed. CysC- and Cr-based eGFR were measured before and three times per week during therapy. To calculate the eGFR, an equation for Japanese children was used. AKI was diagnosed when eGFR dropped by ≥ 25% from the highest eGFR value obtained during the latest 2 weeks since the start of chemotherapy. AKI was graded based on the pediatric Risk, Injury, Failure, Loss, End Stage Renal Disease scale. All patients developed AKI during chemotherapy; however, more than 90% of the cases were mild and eventually recovered. No significant differences were found in the incidence of AKI between CysC- and Cr-based eGFR (p = 0.104). The median time to AKI diagnosis was significantly shorter in the CysC-based eGFR than in the Cr-based eGFR (8 vs. 17 days, p < 0.001). In this study, all patients with pediatric ALL/LBL could develop mild AKI during treatment. CysC-based eGFR is a more effective measure than Cr-based eGFR for the early diagnosis of AKI.

Desmopressin response in nocturnal enuresis without nocturnal polyuria in Japanese children.

OBJECTIVES: To evaluate whether the efficacy of desmopressin differs between patients with and without nocturnal polyuria. METHODS: A total of 65 treatment-naïve children with monosymptomatic nocturnal enuresis were enrolled (45 boys; median age 8.9 years). Patients received desmopressin as their first-line treatment. Four different standards were used (Akashi and Hoashi >0.9 mL/kg/sleeping hour; Hamano >[age + 2] × 25 × 130% mL; the International Children's Continence Society >[age + 1] × 30 × 130% mL; and Rittig >[age + 9] × 20 mL) to assess nocturnal polyuria. The effectiveness of desmopressin was compared between patients with and without nocturnal polyuria according to each standard. A response was defined as a reduction in wet nights of >50%. RESULTS: The desmopressin treatment efficacy rate was 54% for polyuria and 67% for non-polyuria patients (P = 0.20), 45% for polyuria and 68% for non-polyuria patients (P = 0.08), 54% for polyuria and 59% for non-polyuria patients (P = 0.80), and 52% for polyuria and 61% for non-polyuria patients (P = 0.61), for the Akashi and Hoashi's, Hamano's, International Children's Continence Society and Rittig's standards, respectively. CONCLUSIONS: No difference was observed in the short-term clinical efficacy of desmopressin regardless of the presence of nocturnal polyuria. Thus, this might be a feasible treatment option for patients with nocturnal enuresis without nocturnal polyuria.

Reduced urinary excretion of neutrophil gelatinase-associated lipocalin as a risk factor for recurrence of febrile urinary tract infection in children.

BACKGROUND: This study aimed to test the hypothesis that reduced urinary excretions of neutrophil gelatinase-associated lipocalin (NGAL) predispose children to recurrence of febrile urinary tract infection (fUTI). METHODS: Subjects were 38 children diagnosed with fUTI. To examine risk factors for recurrence of fUTI, the subjects were divided into a non-recurrent group and a recurrent group according to the presence or absence of fUTI over 3 years since the first episode. We measured the urinary NGAL levels in patients with fUTI at the non-infected stage in addition to age-matched healthy control children. RESULTS: In a multiple logistic regression analysis, significant differences between the groups were not observed for age, sex, the prevalence of kidney scarring and bladder bowel dysfunction, urinary ß2-microglobulin/creatinine (Cr) level, and serum levels of Cr and Cystatin C, while the recurrent group had significantly more cases with grade III or higher vesicoureteral reflux (p < 0.01). Furthermore, the urinary NGAL/Cr in the recurrent group (median, 3.60 µg/gCr) was significantly lower than that in the non-recurrent group (median, 16.47 µg/gCr; p < 0.01), and age-matched healthy control children (median, 14.14 µg/gCr; p < 0.05). The area under the receiver operating characteristic curve of NGAL/Cr was 0.86 for predicting recurrence of fUTI. A cut-off value of 11.59 µg/gCr had the best accuracy to predict recurrent fUTI yielding a specificity of 78% and a sensitivity of 93%. CONCLUSIONS: Reduced levels of urinary NGAL, which protects against urinary infection, are a risk factor for recurrence of fUTI and could serve as a biomarker.

Risk factors for sodium valproate-induced renal tubular dysfunction.

OBJECTIVE: To explore the risk factors for the development of sodium valproate (VPA)-induced renal tubular dysfunction for early diagnosis and treatment. STUDY DESIGN: The subjects were selected from patients who were diagnosed with epilepsy and administered VPA. Blood and spot urine samples were collected and measured the concentration of VPA, the level of serum phosphorus, serum uric acid, serum free carnitine, serum cystatin-c, and urine ß2-microglobulin (BMG). Patients with urine BMG/creatinine levels above 219.2 were treated as renal proximal tubular dysfunction (RTD), with all others treated as non-RTD. RESULTS: Eighty-seven patients, 4-48 years, 53 men and 34 women, were studied. RTD group is 17 patients and non-RTD group is 70 patients. Univariate analyses revealed that the RTD patients were more likely to be bedridden, receiving enteral tube feeding, taking more anticonvulsants, and demonstrating significantly lower serum levels of free carnitine, uric acid, and phosphorus. Among them, bedridden, free serum carnitine, and phosphorus levels were associated with the development of RTD by multivariate analysis. CONCLUSIONS: Bedridden patients receiving VPA are susceptible to hypocarnitinemia, which can cause RTD and may lead to FS. Therefore, urinary BMG should be measured regularly in all patients receiving VPA to assess renal tubular function. An additional measurement of serum free carnitine level should be considered in patients who developed RTD. Supplementation of carnitine for those patients to prevent such complication deserves for further study.

Urinary C-megalin for screening of renal scarring in children after febrile urinary tract infection.

BackgroundFebrile urinary tract infection (fUTI) in children may cause renal scarring. This study aimed to investigate the usefulness of urinary biomarkers for diagnosing renal scarring after fUTI.MethodsThirty-seven children (median age: 1.36 years, range: 0.52-12.17 years, 25 boys) with a history of fUTI, who underwent renal scintigraphy for 4 months or longer after the last episode of fUTI, were analyzed. A spot urine sample was obtained on the day of renal scintigraphy to measure levels of total protein, N-acetyl-ß-D-glucosaminidase (NAG), ß2-microglobulin (BMG), neutrophil gelatinase-associated lipocalin (NGAL), liver-type fatty acid binding protein (L-FABP), and C-megalin (full-length megalin). Results were corrected for urinary creatinine (Cr) and compared between the group with renal scarring (n=23) and that without scarring (n=14). Urinary levels of C-megalin were also measured in healthy control subjects.ResultsNo significant differences in total protein, NGAL, L-FABP, NAG, and BMG levels were found between the groups. However, C-megalin levels were significantly higher in the renal scarring group than in the non-renal scarring group and healthy controls (P<0.001). A cutoff value of 6.5 pmol/nmol of urinary C-megalin/Cr yielded 73.9% of specificity and 92.9% of sensitivity.ConclusionUrinary C-megalin is useful for diagnosing renal scarring caused by fUTI.

Decreased urinary excretion of the ectodomain form of megalin (A-megalin) in children with OCRL gene mutations.

BACKGROUND: The oculocerebrorenal syndrome of Lowe gene (OCRL) is located on chromosome Xq25-26 and encodes an inositol polyphosphate-5-phosphatase (OCRL-1). Mutations in this gene cause Lowe syndrome (LS) or type 2 Dent disease, of which low-molecular-weight (LMW) proteinuria is a characteristic feature. Megalin is considered to play an important role in the development of renal tubular proteinuria. Two forms of megalin are excreted into the urine: full-length megalin (C-megalin) and megalin ectodomain (A-megalin). We have explored the role of megalin in the development of LMW proteinuria in patients with OCRL mutations by determining urinary megalin fractions. METHODS: We measured A- and C-megalin in spot urine samples from five male patients with OCRL mutations (median age 9 years), using sandwich enzyme-linked immunosorbent assays, and adjusted the obtained values for excreted creatinine. The results were compared with those of 50 control subjects and one patient with type 1 Dent disease (T1D). RESULTS: All patients demonstrated normal levels of urinary C-megalin. However, patients with OCRL mutations or T1D showed abnormally low levels of urinary A-megalin, with the exception of one 5-year-old boy with LS, who was the youngest patient enrolled in the study. CONCLUSIONS: Decreased excretion of urinary A-megalin in four out of five patients with OCRL mutations suggests that LMW proteinuria may be caused by impaired megalin recycling within the proximal tubular cells. Homologous enzymes, similar to inositol polyphosphate-5-phosphatase B in mice, may help to compensate for defective OCRL-1 function during early childhood.

Urinary 8-Hydroxy-2'-Deoxyguanosine: A Biomarker for Radiation-Induced Oxidative DNA Damage in Pediatric Cardiac Catheterization.

OBJECTIVE: To determine the utility of urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG) as a sensitive biomarker for radiation-induced cellular DNA damage in children undergoing cardiac catheterization. STUDY DESIGN: We enrolled pediatric patients with congenital heart diseases requiring cardiac catheterization in conjunction with healthy children and children under sedation as control. Demographic, clinical, laboratory and invasive hemodynamic data, urinary 8-OHdG levels, and radiation exposure measurements were collected prospectively. RESULTS: Nineteen patients, 10 healthy children and 9 children under sedation, were studied. In 19 patients who underwent cardiac catheterization, the median level of 8-OHdG in urine obtained at 24-48 hours after the procedure was significantly higher than at baseline (44.0 vs 17.3 ng/mg creatinine, P = .0001). Furthermore, the urinary 8-OHdG level after the procedure increased in 18 of the 19 study subjects. In contrast, there was no significant difference in 8-OHdG levels between the 2 spot urine samples obtained at arbitrary intervals of 24-48 hours in 10 healthy children (P = .7213), and at baseline and 24-48 hours following echocardiography in 9 children under sedation (P = .1097). Stepwise multiple regression analysis revealed that the cumulative air kerma during the cardiac catheterization was the variable which was strongly and significantly associated with the ratio of post- to precardiac catheterization urinary 8-OHdG levels among the evaluated variables (R(2) = 0.7179, F = 11.0256, P = .0007). CONCLUSIONS: Urinary 8-OHdG could be a useful biomarker for radiation-induced cellular DNA damage in children undergoing diagnostic cardiac catheterization.

Voiding cystourethrography is mandatory in infants with febrile urinary tract infection.

Vesicoureteral reflux (VUR) is common condition in infants with febrile urinary tract infections (UTIs). Both VUR and febrile UTIs are risk factors for renal scars, characterized by glomerular hypertrophy with global or segmental sclerosis as cardinal features in pathology. Because renal scars may cause hypertension or chronic kidney diseases in later life, voiding cystourethrography (VCUG) has been mandatory for infants following their first febrile UTIs to identify VUR. However, increasing evidence suggests that the presence of VUR may not represent a direct risk factor for renal scars, which has led to an increase in the use of a stratified approach, in which VCUG is not performed for all patients. This study was conducted to verify whether the stratified approach is justified to identify infants at risk for renal scarring. The medical records of 306 infants with first febrile UTIs (median age, 4 months; 0-72 months) were reviewed. VUR was detected in 40.4% (67/166) of patients by the non-stratified approach, in which VCUG was performed in all patients. In contrast, VUR was identified in only 27.1% (38/140) of patients by the stratified approach, in which VCUG was performed only in the patients with high risk of developing renal scars. This difference in the discovery rate was significant (p = 0.02). Renal bladder ultrasonography had the sensitivities of as low as 45.7% and 52.9% in detecting VUR and in predicting renal scarring assessed by renal scintigraphy, respectively. In conclusion, VCUG should be performed in all infants after their first febrile UTIs.

Significance of twinkling artifact on ultrasound in the diagnosis of cystine urolithiasis.

Twinkling artifact (TA) refers to the finding characterized by both a high-echoic mass upon B-mode ultrasound (US) and turbulence-like signals over the entire mass without significant blood flow on color Doppler US. TA is a characteristic sign of urolithiasis, and there has been no previous report on this finding in the digestive tract. The authors recently encountered a 2-year 9-month-old boy with cystinuria presenting with an opacified abdominal mass. Although he was originally diagnosed as having calcified stool mass, the finding of TA upon US led to the correct diagnosis of huge urolith (4.2 cm in diameter) in the urinary bladder. Laparotomic stone removal was successfully conducted and the calculus was confirmed to be composed of cystine. The finding of TA upon US facilitates identification of the structure and location of the intra-abdominal mass.

Different phenotypes of HNF1ß deletion mutants in familial multicystic dysplastic kidneys.

Multicystic dysplastic kidney (MCDK) is one of the most common congenital abnormalities of the kidney and urinary tract (CAKUT), although its pathophysiology remains unknown. Familial occurrence of MCDK suggests that mutations in genes associated with nephrogenesis are involved in the pathogenesis in at least some cases. Hepatocyte nuclear factor 1ß (HNF1ß) is a member of the homeodomain-containing super family of transcription factors, and is known to regulate tissue-specific gene expression in a number of organs including the kidneys, pancreas and liver. It has been recently postulated to be associated with CAKUT, including MCDK. We recently encountered a family with a deletion mutant of HNF1ß, of which the 2nd son, the proband, developed bilateral MCDK resulting in renal loss of function in infancy while the 1st son developed unilateral MCDK. Their father has two normal kidneys. This family confirmed that mutations in the HNF1ß gene are strongly associated with the development of MCDK. Furthermore, the fact that no clear phenotype-genotype correlation exists suggests that gene(s) other than HNF1ß are also involved in nephrogenesis and the development of MCDK.

A child with Epstein-Barr Virus-associated hemophagocytic lymphohistiocytosis complicated by coronary artery lesion mimicking Kawasaki disease.

There is considerable overlap between hemophagocytic lymphohistiocytosis (HLH) and Kawasaki disease (KD) in terms of aberrant immune response though the etiology of KD remains unknown. We present a case fulfilling the criteria of both HLH and KD complicated by coronary artery dilatation: HLH was confirmed to be triggered by Epstein-Barr virus. This case alarms us the possibility that even patients with HLH may be complicated by coronary artery lesion, which is one of the hallmarks of KD. We would like to draw attention that if features of KD become apparent in patients with HLH, echocardiographic examinations should be performed not to miss coronary artery lesion.

A novel nuclear factor κB inhibitor, dehydroxymethylepoxyquinomicin, ameliorates puromycin aminonucleoside-induced nephrosis in mice.

BACKGROUND/AIMS: Minimal-change nephrotic syndrome (MCNS) is a kidney disease defined by selective proteinuria and hypoalbuminemia occurring in the absence of cellular glomerular infiltrates or immunoglobulin deposits. Recent observations suggest that nuclear factor κB (NF-κB) of podocyte is strongly associated with the development of proteinuria in MCNS. Dehydroxymethylepoxyquinomicin (DHMEQ) is a novel NF-κB inhibitor that potently inhibits DNA-binding activity of NF-κB, resulting in several therapeutic effects in various pathological conditions. We conducted this study to ask whether DHMEQ may ameliorate the nephrosis in mice induced by puromycin aminonucleoside (PAN), which is considered to be an animal model for MCNS. METHODS/RESULTS: Pretreatment with DHMEQ alleviated the proteinuria and reversed the serum abnormalities in mice nephrosis induced by 450 mg/kg of PAN. Increased serum interleukin-6 level in PAN-induced nephrosis was also completely suppressed by DHMEQ. Electron microscopic analyses of glo-meruli indicated that DHMEQ can inhibit the podocyte foot process effacement via blocking the translocation of podocyte NF-κB from cytoplasm to nucleus. CONCLUSIONS: These results suggest that DHMEQ can be a potential therapeutic agent for MCNS.