Proteomic analysis of inhibitory protein profiles in the urine of children with nephrolithiasis: implication for disease prevention.

PURPOSE: In this study we aimed to screen for the presence of biomarkers that are downregulated in children with nephrolithiasis (RS) compared to healthy controls (HC) using a proteomic approach. We hypothesized that RS and HC would display unique inhibitory protein profiles that could be used for comparative pathway analysis. METHODS: This is a prospective, controlled, pilot study of pooled urine from RS (N = 30, 24 females, mean age 12.95 ± 4.03 years) versus age- and gender-matched HC, using liquid chromatography-mass spectrometry. The criteria for protein selection were: (1) patient/control abundance ratio of < 0.5; and (2) ≤ 0.05 p-value for the Fisher's Exact Test. Results were confirmed by ELISA testing in individual samples. RESULTS: 67 proteins were downregulated in RS group, and 17 of those were significantly different compared to controls. Of those seventeen proteins, five (two actins, annexin A5, keratin 6B, and serpin B4) were completely absent in the urine of stone patients but were found in controls. The remaining twelve proteins were significantly less abundant in the patient's urine compared to healthy controls. Protein-protein interaction modeling of significant proteins identified syndecan-1 as the key node, a protein associated with adhesion pathways. ELISA analysis by subgroups showed statistically significant difference in the urinary excretion of osteopontin (5.1 ± 3.22 ng/mg creatinine vs 14.1 ± 9.5 ng/mg creatinine, p = 0.046) between stone patients with hypocitraturia and controls. Urinary osteopontin concentration was positively correlated with urinary citrate excretion (r = 0.417, p = 0.03). CONCLUSIONS: Children with RS have a different urinary inhibitory polypeptide profile compared to HC. Decreased urinary excretion of these proteins indicates their potential inhibitory role in renal stone formation, especially of the adhesion phase. Lower concentration of urinary osteopontin in children with nephrolithiasis and hypocitraturia suggests its potential involvement in the pathogenesis of this disease. Further characterization of these proteins in a larger sample is imperative.

Diagnosis and Management of Nephrolithiasis in Children.

The incidence of kidney stones in children is increasing. Approximately two-thirds of pediatric cases have a predisposing cause. Children with recurrent kidney stones have an increased higher risk of developing chronic kidney. A complete metabolic workup should be performed. Ultrasound examination is the initial imaging modality recommended for all children with suspected nephrolithiasis. A general dietary recommendation includes high fluid consumption, dietary salt restriction, and increased intake of vegetables and fruits. Depending on size and location of the stone, surgical intervention may be necessary. Multidisciplinary management is key to successful treatment and prevention.

Cystatin C, Neutrophil Gelatinase-associated Lipocalin, and Lysozyme C: Urinary Biomarkers for Detection of Early Kidney Dysfunction in Children With Urolithiasis.

OBJECTIVE: To screen for the presence of biomarkers involved in tubular injury and kidney damage in children with urolithiasis (RS), and to validate these proteins by ELISA. METHODS: Prospective-controlled pilot study of children with urolithiasis and their age- and gender-matched controls (HC). Initial screening test was done by quantitative proteomic comparison of pooled urine from RS versus HC, using liquid chromatography-mass spectrometry. Proteins of interest were selected using the following criteria: (1) ≥5 spectral counts; (2) ≥2-fold difference in spectral counts; and (3) ≤.05 P value for the Fisher's Exact Test. Validation was performed by ELISA testing. Statistical analysis was performed by Student t-test and Mann-Whitney U test. RESULTS: Proteomic analysis identified 3 proteins of interest, Cystatin C (CYTC), neutrophil gelatinase-associated lipocalin (NGAL) and lysozyme C that were significantly over-represented in RS group versus HC. ELISA analysis revealed significantly increased urinary levels of CYTC and NGAL, and nearly significantly increased urinary levels of lysozyme C in RS group (N = 24) compared to controls (N = 13). Subgroup analysis showed significantly higher urinary levels of CYTC in both hypercalciuria (N = 14) and hypocitraturia (N = 10) versus HC (P <.05). CONCLUSION: Children with urolithiasis showed significant increase in urinary CYTC and NGAL irrespective of their normal serum creatinine. These biomarkers indicate tubular injury and early kidney damage and represent valid tools for early screening when traditional tests are normal.

Effect of bisphosphonates on the crystallization of stone-forming salts in synthetic urine.

Purpose: We investigated the inhibitory effect of bisphosphonates (BPs) on the crystallization of calcium oxalate monohydrate (COM), calcium phosphate (CaP), and magnesium ammonium phosphate (MAP) in synthetic urine, aiming to see 1) which specific BPs work best on a particular type of crystal and 2) what is the lowest concentration of BPs that inhibits crystal formation. Materials and Methods: Crystals from synthetic urine were exposed to different concentrations of BPs. Urinary turbidity was used as a marker of crystallization and was measured by spectrophotometry by use of a validated method in our laboratory. The percent inhibitory activity (IA) was calculated by using the formula: (a-b )/a×100, where a is baseline maximal turbidity and b is maximal turbidity with various concentrations of medication. Potassium citrate and magnesium citrate were used as positive controls. Results: At the lowest dose of 0.001 mg/mL, risedronate induced the highest IA of 37% on CaP, whereas ibandronate had the strongest IA on COM (24%). To initiate the inhibition of MAP crystallization, risedronate required a two-fold higher concentration (0.002 mg/mL) to reach 30% IA, whereas etidronate required a four-fold higher concentration (0.004 mg/mL) to reach 42% IA. Conclusions: BPs are good inhibitors of crystallization in synthetic urine, with risedronate and ibandronate being the most potent. At a low clinically acceptable dose, their highest inhibitory action was on CaP and COM crystals. Higher doses were needed to prevent MAP crystallization. Further investigation of the use of BPs in kidney stone prevention is warranted.

Management and treatment of nocturnal enuresis-an updated standardization document from the International Children's Continence Society.

BACKGROUND: Enuresis is an extremely common condition, which, although somatically benign, poses long-term psychosocial risks if untreated. There are still many misconceptions regarding the proper management of these children. AIM: A cross-professional team of experts affiliated with the International Children's Continence Society (ICCS) undertook to update the previous guidelines for the evaluation and treatment of children with enuresis. METHODS: The document used the globally accepted ICCS terminology. Evidence-based literature served as the basis, but in areas lacking in primary evidence, expert consensus was used. Before submission, a full draft was made available to all ICCS members for additional comments. RESULTS: The enuretic child does, in the absence of certain warning signs (i.e., voiding difficulties, excessive thirst), not need blood tests, radiology or urodynamic assessment. Active therapy is recommended from the age of 6 years. The most important comorbid conditions to take into account are psychiatric disorders, constipation, urinary tract infections and snoring or sleep apneas. Constipation and daytime incontinence, if present, should be treated. In nonmonosymptomatic enuresis, it is recommended that basic advice regarding voiding and drinking habits be provided. In monosymptomatic enuresis, or if the above strategy did not make the child dry, the first-line treatment modalities are desmopressin or the enuresis alarm. If both these therapies fail alone or in combination, anticholinergic treatment is a possible next step. If the child is unresponsive to initial therapy, antidepressant treatment may be considered by the expert. Children with concomitant sleep disordered breathing may become dry if the airway obstruction is removed.

Comorbid monosymptomatic nocturnal enuresis and snoring exhibit an additive effect on impairments in health-related quality of life.

INTRODUCTION/BACKGROUND: Health-related quality of life (HRQOL) is a relatively new concept in pediatrics, but it has shown to be extremely important in terms of clinical care, treatment planning, and compliance with medical and behavioral recommendations. Two groups of children who are at risk for impairments in HRQOL are those who have bed-wetting and those who snore or have sleep apnea. OBJECTIVE: The present study sought to determine whether the combination of monosymptomatic nocturnal enuresis (MNE) and sleep-disordered breathing (SDB) results in diminished HRQOL in a pediatric sample. STUDY DESIGN: A retrospective chart review was conducted in an outpatient pediatric urology clinic and in an outpatient pulmonology clinic. Parents of the patients completed the Pediatric Sleep Questionnaire (PSQ) to assess the presence of SDB and snoring, and HRQOL was assessed using the Obstructive Sleep Apnea Syndrome-18-item (OSAS-18) scale, both validated measures, as part of the child's clinical workup. RESULTS: One hundred fifty-two (85 males and 67 females ) patients were included and were categorized into any of the following four groups: (1) MNE only, (2) SDB only, (3) MNE + SDB, or (4) healthy control. Patients in the SDB-only group had significantly more severe SDB than those in the other groups. As such, severity of SDB was controlled for in analyses. Results revealed that the four groups significantly differed on all subscales of the OSAS-18, which are Sleep Disturbance, Physical Symptoms, Emotional Symptoms, Daytime Functioning, and Caregiver Concerns. Post hoc analyses revealed the MNE + SDB group had more impairments on each subscale. Analysis of the total impairments revealed that children with only one condition (MNE or SDB) reported similar levels of impairments in HRQOL and patients with MNE + SBD reported significantly higher levels of impairments, as it appears that these comorbid conditions have an additive effect on HRQOL. DISCUSSION: Children with comorbid MNE and SDB are at significantly higher risk for reporting impairments in their HRQOL than children who have only one of these conditions. While it is already known that children with MNE are at risk for emotional, behavioral, and social difficulties and children with SDB are at risk for neurobehavioral difficulties, it is possible that children with both conditions are at risk for a multitude of negative consequences. CONCLUSION: These data emphasize the importance of urologist screening for SDB and pulmonologist screening for MNE as part of their routine clinical practice.

Urine proteomic profiling in patients with nephrolithiasis and cystinuria.

PURPOSE: The purpose of the study was to assess the differences in the concentration and function of urinary proteins between patients with cystine stones (CYS) and healthy controls (HC). We postulated that CYS and HC groups would demonstrate different proteomic profiles. METHODS: A pilot study was performed comparing urinary proteomes of 10 patients with CYS and 10 age- and gender-matched HC, using liquid chromatography-mass spectrometry. Proteins which met the selection criteria (i) ≥ 2 unique peptide identifications; (ii) ≥ twofold difference in protein abundance; and (iii) ≤ 0.05 p value for the Fisher's Exact Test were analyzed using Gene Ontology classifications. RESULTS: Of the 2097 proteins identified by proteomic analysis, 398 proteins were significantly different between CYS and HC. Of those, 191 were involved in transport processes and 61 in inflammatory responses. The majority were vesicle-mediated transport proteins (78.5%), and 1/3 of them were down-regulated; of those, 12 proteins were involved in endosomal transport (including 6 charged multivesicular body proteins (CHMP) and 3 vacuolar sorting-associated proteins) and 9 in transmembrane transport. Myosin-2 and two actin-related proteins were significantly up-regulated in the vesicle-mediated transport group. CONCLUSION: We provide proteomic evidence of impaired endocytosis, dysregulation of actin and myosin cytoskeleton, and inflammation in CYS. Endosomal transport proteins were down-regulated mainly through defective CHMP. These findings may contribute to further understanding of the pathogenesis of CYS, potentially affecting its management.

Urinary proteomics reveals association between pediatric nephrolithiasis and cardiovascular disease.

PURPOSE: To study (1) the differences in the relative abundance of urinary proteins between children with kidney stones (RS) and hypercalciuria, hypocitraturia, normal metabolic work-up, and healthy controls (HC); (2) the association of these proteins with various diseases. METHODS: Quantitative proteomic comparison of pooled urine from RS (N = 30, 24 females, mean age 12.95 ± 4.03 years) versus age- and gender-matched HC, using mass spectrometry. Relative protein abundance was estimated using spectral counting. Proteins of interest were selected using the following criteria: (1) ≥ 5 spectral counts; (2) ≥ twofold difference in spectral counts; and (3) ≤ 0.05 p value for the Fisher's Exact Test. RESULTS: Of the 1813 proteins identified, 229 met the above criteria, with 162 proteins up-regulated in the RS group and 67 up-regulated in HC. The largest group of proteins (30 out of 229) was found to be associated with cardiovascular disease (CVD). Of those, 16 were involved in coagulation, fibrinolysis, and adhesion, 10 in inflammation, 5 in lipid transport and metabolism, and 4 in oxidative stress. All except two were exclusively found in children with hypercalciuria and hypocitraturia, and were not seen in children with normal metabolic work-up. CONCLUSION: Using a proteomic approach, we found a significant association between hypercalciuric and hypocitraturic nephrolithiasis and CVD in children. The shared risk factors among both diseases are endothelial dysfunction and atherosclerosis caused by abnormal coagulation, adhesion, disturbance of lipid transport and metabolism, oxidative stress and inflammation. Further understanding of the pathophysiological link between nephrolithiasis and CVD is necessary for developing new therapeutic targets.

Children with nocturnal enuresis and attention deficit hyperactivity disorder: A separate entity?

INTRODUCTION: There is ongoing debate about whether nocturnal enuresis (NE) is affected by the presence of attention deficit hyperactivity disorder (ADHD) in children. Clarifying this relationship could categorize them as a separate entity, potentially requiring a different management from enuretic children without ADHD. AIMS: To study whether (1) children with ADHD exhibited greater severity of enuresis and associated voiding symptoms compared with children without ADHD, (2) whether there was a difference in enuretic response to treatment between children with/without ADHD, (3) whether previously prescribed medication for ADHD affected severity of enuresis or voiding symptoms, and response to treatment. METHODS: Data on all consecutive children seen with primary NE and ADHD and age- and gender-matched children with NE without ADHD over the course of 2 years were extracted from our database. Controls were identified using a random number generator to choose patients within each age/gender group. Changes in Dysfunctional Voiding Scoring System (DVSS) and Bristol scores were assessed before and after treatment for NE using repeated measures ANOVAs. Number of weekly wet nights was compared between the groups before and after the treatment of enuresis. Children with more than a 50% decrease in number of wet nights per week were categorized as responding to treatment. RESULTS: Compared with controls, ADHD children (N = 95) had significantly more severe voiding symptoms, NE and constipation (Table). No significant differences were found between children on ADHD medication (63.2%) and those who were not on ADHD medication (36.8%) on any of the demographic and pre-treatment clinical parameters. Similar enuretic response rates to behavioral modification alone were seen in both study (13.5%) and control (12.8%) groups (p = 0.73). Response to pharmacological treatment was seen in nine patients with ADHD (42.9%) and in six (20.7%) controls, with pharmacological intervention being significantly more effective than behavioral modification for patients with ADHD (p = 0.012). Additionally, no difference was found between ADHD patients on and off ADHD medication in terms of response to enuresis treatment. CONCLUSION: In children with primary NE, the presence of ADHD was associated with more severe NE, voiding symptoms and constipation. The severity of voiding symptoms and/or NE was unrelated to the use of stimulant medication. The response to behavioral modification was comparable in both groups. However, patients with ADHD were significantly more responsive to medication for NE compared with behavioral modification, indicating a possible benefit for earlier pharmacological treatment for enuresis in this population subgroup.

24 Hour urine metabolic differences between solitary and multiple stone formers: Results of the Collaboration on Urolithiasis in Pediatrics (CUP) working group.

INTRODUCTION: Specific factors associated with the risk of developing pediatric urinary stone disease remain unclear, especially those that may be associated with recurrent stone disease. OBJECTIVE: We compared the results of 24-h urine collections in children with a solitary stone episode to those with multiple stone episodes to determine if there is a difference that may be associated with multiple stone formation in children. STUDY DESIGN: A multi-institutional retrospective analysis was completed to assess 24-h urinary metabolic profiles in children with urolithiasis aged 2-18 years old. Differences in mean urine collections between the two groups were assessed using chi-square tests to test the associations among gender, stone type, and multiple stone status, as well as multivariate analyses using general linear models. RESULTS: We analyzed 142 solitary stone patients and 136 multiple stone patients from four centers were included. Multiple stone patients were older than solitary stone patients (mean 13.4 ± 3.6 years vs. 12 ± 3.9 years, p = 0.002). Females were more likely to have multiple stones (58% vs. 39%, p = 0.002). BMI was not associated with multiple stones (p = 0.8467). Multiple stone formers had lower urine volumes, although this did not reach statistical significance when compared with solitary stone formation (20.4 mL/kg/day ± 11.5 vs. 22.9 ± 13.0, p = 0.0880). Higher values for super-saturation of calcium oxalate were associated with multiple stone disease in univariate (p = 0.0485) and multivariate analysis (p = 0.0469) (Figure). Centers located in the Southeast of the United States saw a higher proportion of children with multiple stones (Tennessee 62.7%, Virginia 44.4%, Oregon 31.6%, Michigan 27.3%, p < 0.0001). DISCUSSION: In a large multi-institutional retrospective analysis we found that multiple stone disease was associated with higher super-saturations of calcium oxalate. Many urinary parameters changed with patient age, highlighting that the values should be interpreted with respect to patient age. The inability to comment on follow-up because of the nature of our dataset is a limitation of this study. CONCLUSION: Multiple stone disease in children is associated with higher super-saturation calcium oxalate, while lower urinary volume may also be associated with multiple stones; however, further study is required. Early metabolic evaluation may help risk stratify children likely to form multiple stones.

Marked increase in urinary excretion of apolipoproteins in children with nephrolithiasis associated with hypercalciuria.

BACKGROUND: Using a proteomic approach, we aimed to identify and compare the urinary excretion of proteins involved in lipid transport and metabolism in children with kidney stones and hypercalciuria (CAL), hypocitraturia (CIT), and normal metabolic work-up (NM), and in healthy controls (HCs). Additionally, we aimed to confirm these results using ELISA, and to examine the relationship between the urinary excretion of selected proteins with demographic, dietary, blood, and urinary parameters. METHODS: Prospective, controlled, pilot study of pooled urine from CAL, CIT, and NM versus age- and gender-matched HCs, using liquid chromatography-mass spectrometry. Relative protein abundance was estimated using spectral counting. Results were confirmed by ELISA performed on individual samples. RESULTS: Of the 1,813 proteins identified, 230 met the above criteria. Of those, 5 proteins (apolipoprotein A-II [APOA2]; apolipoprotein A-IV [APOA4]; apolipoprotein C-III [APOA3]; fatty acid-binding protein, liver [FABPL]; fatty acid-binding protein, adipocyte [FABP4]) involved in lipid metabolism and transport were found in the CAL group, with significant differences compared with HCs. ELISA analysis indicated statistically significant differences in the urinary excretion of APOC3, APOA4, and FABPL in the CAL group compared with HCs. Twenty-four-hour urinary calcium excretion correlated significantly with concentrations of ApoC3 (r = 0.77, p < 0.001), and FABPL (r = 0.80, p = 0.005). CONCLUSIONS: We provide proteomic data showing increased urinary excretion of lipid metabolism/transport-related proteins in children with kidney stones and hypercalciuria. These findings suggest that abnormalities in lipid metabolism might play a role in kidney stone formation.

Do Overweight and Obese Pediatric Stone Formers Have Differences in Metabolic Abnormalities Compared With Normal-weight Stone Formers?

OBJECTIVE: To determine if 24-hour urinary parameters in children with nephrolithiasis across 4 institutions were influenced by body mass index (BMI). MATERIALS AND METHODS: The 24-hour urinary parameters obtained from children with nephrolithiasis between 2000 and 2013 were stratified by BMI percentile ≥85th and <85th (overweight and obese patients vs healthy weight, respectively). A total of 206 children were included in the study. Exclusion criteria included patients with a history of spina bifida, neurogenic bladder, and cerebral palsy, and patients on medical treatment before the first 24-hour urine collection. RESULTS: Overweight and obese patients consisted of 35.4% of the cohort (n = 73). Metabolic abnormalities were present in 130 children (63.1%). The most common abnormality present in the <85th percentile was hypercalciuria (32.3%), and in the ≥85th percentile, hyperoxaluria (37.0%). Univariable and multivariable analyses revealed that overweight and obese children were more likely to have low urinary volume and elevated uric acid compared to normal-weight children. CONCLUSION: Although there is a link between stone formation and BMI in adults, no definitive conclusions have been proven in the pediatric literature. Our study indicates that stone-forming children who are overweight or obese have low urinary volume and elevated uric acid compared to normal-weight stone-forming children.

Renal Tubular Dysfunction in Pediatric Urolithiasis: Proteomic Evidence.

OBJECTIVE: To investigate whether inflammation, oxidation, and tubular injury are present in children with stones (RS) compared with healthy controls (HC) by measuring urinary proteins involved in these processes. METHODS: Quantitative proteomic comparison of pooled urine from RS (N = 30, 24 females, mean age 12.95 ± 4.03 years) versus age- and gender-matched HC (N = 30), using liquid chromatography-mass spectrometry. Relative protein abundance was estimated using spectral counting. Proteins of interest were selected using the following criteria: (1) ≥5 spectral counts; (2) ≥2-fold difference in spectral counts; and (3) P-value ≤.05 for Fisher's exact test. RESULTS: Of the 1813 proteins identified, 230 met the above criteria, with 163 proteins upregulated in the RS group and 67 upregulated in HC. Functional analysis revealed 19 inflammatory proteins, 5 proteins involved in oxidative stress, and 5 involved in tubular injury. Of those proteins, NADPH-oxidase, a major source of reactive oxygen species, was only found in the RS group, whereas glutathione S-transferase A2, an important antioxidant enzyme, was more abundant in controls. ELISA analysis confirmed statistically significant differences in the urinary excretion of retinol-binding protein 4, a marker of proximal tubular dysfunction, between stone patients with hypercalciuria and controls. CONCLUSION: We provide proteomic evidence of oxidative stress, inflammation, and tubular injury in children with renal stones. We speculate that inflammation and changes in the oxidant-antioxidant balance may cause tubular damage in these patients. Targeting these proteins may have therapeutic benefits.

Evidence of Need to Use Self-Report Measures of Psychosocial Functioning in Older Children and Adolescents with Voiding Dysfunction.

PURPOSE: Previous reports have revealed significantly higher rates of psychosocial difficulties in children and adolescents with voiding dysfunction compared to their healthy peers. However, these findings are based solely on parental reporting and do not include self-reporting of psychosocial problems in older pediatric patients. MATERIALS AND METHODS: We collected data from 200 consecutive patients 11 to 16 years old during outpatient clinic visits. Patients completed the Pediatric Symptom Checklist-Youth Report, parents completed the parental report of the same measure, and patients and parents collaboratively completed the Dysfunctional Voiding Scoring System. RESULTS: Of the patients 25.5% met the cutoff score for clinically significant levels of psychosocial difficulties. However, only a fourth of those patients met the cutoff on the parent and self-report measures. Additionally patient self-reports of internalizing and externalizing problems were significantly related to severity of voiding dysfunction. CONCLUSIONS: Screening for psychosocial problems in older children and adolescents with voiding dysfunction should include reports from the parent and the child. In our sample 37.3% of patients needing a mental health followup would have been missed if only 1 version of the measure had been administered.

Adenotonsillectomy Normalizes Hormones and Urinary Electrolytes in Children With Nocturnal Enuresis and Sleep-Disordered Breathing.

OBJECTIVE: To assess (1) plasma levels of antidiuretic hormone (ADH) and brain natriuretic peptide (BNP) and urinary levels of electrolytes in children with sleep disordered breathing (SDB), with or without nocturnal enuresis (NE), and (2) the effect of adenotonsillectomy (T&A) on urinary electrolytes and the secretion of ADH and BNP in children with NE and SDB. We previously reported post-T&A improvements in plasma levels of BNP and ADH in children with SDB and NE. However, the differences in plasma concentration of these hormones in SDB children with and without NE, and their relationships with urinary electrolytes, have not yet been addressed. METHODS: This prospective study compared concentrations of urinary electrolytes and plasma ADH and BNP in (1) children with SDB and NE (study group) and an age- and sex-matched control group of children with SDB without NE, and (2) the study group before and 1-month after T&A. RESULTS: Compared with the control group (n = 31), the study group (n = 37) exhibited significantly lower ADH (P = .04) and higher BNP (P = .009) plasma levels. The differences in urinary electrolytes were not significant. Post-T&A, the study group showed significantly decreased BNP (P = .018), urinary sodium-to-creatinine ratio (P = .02), and urinary calcium-to-creatinine ratio (P = .007) compared with the pre-T&A values. Post-T&A changes in urinary calcium were significantly correlated with changes in sodium excretion (P = .002) and in plasma levels of BNP (P <.001). CONCLUSION: The presence of NE is associated with altered ADH and BNP levels in children with SDB. T&A led to normalization of ADH and BNP, probably through a calcium- and sodium-dependent mechanism.

National multi-institutional cooperative on urolithiasis in children: Age is a significant predictor of urine abnormalities.

INTRODUCTION: Pediatric nephrolithiasis is a growing problem and prior studies have shown the greatest increase in nephrolithiasis in the adolescent population. Metabolic abnormalities have historically been cited as the primary cause of pediatric nephrolithiasis; however, dietary and other factors such as obesity have also been studied with mixed results. OBJECTIVE: We reviewed the charts of pediatric patients with a history of nephrolithiasis to determine the number and types of metabolic abnormalities present on 24-h urine analysis. STUDY DESIGN: We retrospectively reviewed the charts of all pediatric patients with a history of nephrolithiasis from 1999-2013 across four different institutions. The subjects were excluded if they had a history of spina bifida, neurogenic bladder, cerebral palsy, isolated bladder stones, or if they were on medical therapy for nephrolithiasis before the first 24-h urine collection. RESULTS: There were 206 subjects included in the analysis with an average age of 13 (±3.9) years. The patients were stratified into two age groups based on an apparent bimodal distribution of metabolic abnormalities, ≤10 years and >10 years of age. Metabolic abnormalities were present in 130 children (63.1%) and there was a difference between the groups, with children ≤10 years more likely to have a metabolic abnormality compared with those >10 years of age (75% vs. 60.6%, p = 0.0443) on univariate analysis. In children ≤10 years hypercalciuria was the most common disorder present (48.4%), and in children >10 years hypocitraturia was the most common disorder present (26.1%). Children ≤10 years of age were more likely to have normal volume (p = 0.006), elevated urinary oxalate (p = 0.0351), elevated urinary calcium (p < 0.001), elevated supersaturation of calcium phosphate (p < 0.001), and elevated supersaturation of calcium oxalate (p = 0.002). On multivariate analysis, children ≤10 years of age were more likely to have normal volume, hyperoxaluria, elevated supersaturation of calcium phosphate and a trend towards hypercalciuria (Table). DISCUSSION: Our study reveals that younger children are more likely to have a metabolic abnormality present on 24-h urine analysis. This has important implications when deciding on treatment options, with younger children potentially requiring more aggressive management with medical therapy. Older children were more likely to have low urinary volume and their most common metabolic abnormality was hypocitraturia. Although dietary factors have not been established as the definitive reason behind the rising incidence of nephrolithiasis in the adolescent population, older children may benefit more from diet modification with a strong focus on increasing volume intake. CONCLUSION: We found differences in younger compared with older age groups in terms of the number and types of metabolic disorders present. Children ≤10 years of age were more likely to have a metabolic disorder including elevations in calcium, oxalate and supersaturation of calcium phosphate, while children >10 years of age were more likely to have low urinary volume. These differences have important implications for future investigative studies on the rising incidence as well as the best course of treatment for children with nephrolithiasis.

Adenotonsillectomy improves quality of life in children with sleep-disordered breathing regardless of nocturnal enuresis outcome.

BACKGROUND: Nocturnal enuresis (NE) and sleep-disordered breathing (SDB) have both been associated with impaired health-related quality of life (HRQoL). The following were investigated: (1) whether tonsillectomy and/or adenoidectomy (T&A) significantly affect the HRQoL in children with NE and SDB, and 2) differences in HRQoL between children with NE persistence versus resolution post-T&A. METHODS: This was a prospective study comparing the HRQoL of children with SDB and NE (study group) pre- and 4 weeks post-T&A, and the HRQoL of children with SDB without NE (control group) (independent t-tests). HRQol was assessed using the Obstructive Sleep Apnea Quality of Life 18 questionnaire (OSAS-18), a validated measure containing five subscales that combine to create a total score. Individual items were scored on a Likert-type scale ranging from 1 (none of the time) to 7 (all of the time). Symptoms of SDB were evaluated using the validated Pediatric Sleep Questionnaire (PSQ). Mixed ANOVA was conducted to evaluate changes in the measures between the wet and dry children post-T&A. Pre- and post-T&A change scores were calculated for both the PSQ and the OSAS-18. RESULTS: There were 30 children in the study group (18 male, mean age 9.07 years, SD 2.19), and 30 age-matched controls (16 male). There were no statistically significant differences between the two groups in regards to OSAS-18 total, PSQ total, BMI, diagnosis of snoring or OSAS on sleep study, or race. Overall, OSAS-18 and PSQ scores significantly improved in all children post-surgery (p < 0.001; p < 0.001, respectively), with no significant differences between dry and wet children post-T&A. The correlation between the pre- and post-T&A change scores on the OSAS-18 and PSQ was significant (r(29) = 0.58, p = 0.001), suggesting that a reduction in SDB symptoms post T&A is related to improved HRQoL. CONCLUSIONS: T&A significantly improved HRQoL in all children with SDB and NE, regardless of NE outcomes. These findings support recommendations for T&A in children with SDB with or without NE.

Urine proteomic analysis in cystinuric children with renal stones.

INTRODUCTION: The gene mutations responsible for cystinuria do not fully explain kidney stone activity, suggesting that specific proteins may serve as promoters of cystine precipitation, aggregation or epithelial adherence. In this study we assessed (1) the differences in the urinary proteins between children with cystinuria and kidney stones (CYS) and healthy controls (HC), with particular attention to the fibrosis-related proteins, and (2) the presence of diagnostic biomarkers for CYS. MATERIAL AND METHODS: We conducted a pilot study comparing individual urinary proteomes of 2 newly diagnosed children with CYS and 2 age- and gender-matched HC, using liquid chromatography-mass spectrometry. Relative protein abundance was estimated using spectral counting. Proteins of interest in both CYS and HC were selected using the following criteria: i) ≥5 spectral counts; ii) ≥2-fold difference in spectral counts; and iii) ≤0.05 p-value for the Fisher's Exact Test. DISCUSSION: This study demonstrates a different urinary polypeptide profile in two children with CYS compared to two HC. Of the 623 proteins identified by proteomic analysis, 180 exhibited at least a 2-fold increased relative abundance in CYS compared to HC. Of these, 39 were involved in response to stress, 26 in response to wounding, 21 in inflammatory response, 18 in immune response, and 4 in cellular response to oxidative stress. 133 proteins were found only in children with CYS, 33 of which met the selection criteria. Of these 33 unique proteins, six are known to be associated with fibrosis pathways (Table). The major limitation of this study is the small number of samples that were analyzed. Validation using highly specific methods such as ELISA is needed. CONCLUSION: We provide proteomic evidence of oxidative injury, inflammation, wound healing and fibrosis in two children with CYS. We speculate that oxidative stress and inflammation may cause remodeling via actin and vimentin pathways, leading to fibrosis. Additionally, we identified ITIH and MMP-9 as potential diagnostic biomarkers and novel therapeutic targets in CYS. These proteins merit further investigation.