Long-term Effects of Kidney Transplantation Compared With Dialysis on Intima-media Thickness in Children-Results From the 4C-T Study

BACKGROUND

Children requiring kidney replacement therapy experience high burden of cardiovascular (CV) disease leading to increased mortality. Intima-media thickness (IMT) indicating atherosclerosis is a validated surrogate marker for future CV events.

METHODS

We investigated the effect of different treatment modalities (dialysis, preemptive kidney transplantation (KTx), late KTx after dialysis) on IMT by multivariable linear mixed-effect modeling. Patients were enrolled in a prospective cohort study.

RESULTS

A total of 261 analyzed children had a mean follow-up of 3 y. Children after preemptive and late KTx had lower levels of IMT when compared with dialysis. Using an interaction term, a significant progression of IMT over time was seen during dialysis (β = 0.0053 mm/y, P   =  0.004). IMT before the start of therapy was the most influential determinant in all models. Low IMT was associated with maintenance steroid treatment after preemptive KTx. High IMT on dialysis was associated with higher systolic blood pressure, lower body mass index, lower serum albumin, and lower bicarbonate.

CONCLUSIONS

IMT remained rather stable in children several years after KTx. In contrast, children on dialysis had higher IMT values, which increased over time. In these children, blood pressure control, calorie and protein intake, and acid-base homeostasis seem important. Taken together, children might profit from early transplantation to limit accumulation of CV risk.

Factors predicting kidney replacement therapy in pediatric earthquake victims with crush syndrome in the first week following rescue

Crush syndrome due to traumatic rhabdomyolysis is one of the most significant problems to occur following earthquakes. On February 6, 2023, millions of people in Turkey were affected by two consecutive Kahramanmaraş earthquakes. The present study reports the analysis of clinical and laboratory findings of crush syndrome in pediatric earthquake victims admitted to our hospital from our region where the earthquake had a devastating effect. Clinical and laboratory findings concerning earthquake victims with crush syndrome were analyzed within the first week to determine what factors are predictive of kidney replacement therapy (KRT). The data of patients were retrospectively collected from medical records. A total of 310 children were admitted as earthquake victims to the pediatric emergency department. Ninety-seven (31%) of these patients had crush syndrome. Fifty-three (55%) of those with crush syndrome were female. The mean age was 10.9 ± 4.7 years, and the mean time under the rubble was 30.6 ± 23.8 h. Twenty-two patients (23%) required KRT. Hemodialysis was applied to 16 (73%) of them, and hemodiafiltration was applied to the other six (27%) in the pediatric intensive care unit. Regarding creatine kinase (CK) levels, the area under the receiver operating characteristic (ROC) curve (AUC) for predicting KRT was 0.905 (95% confidence interval [CI] 0.848-0.963; p < 0.001). The optimal cut-off value was 40,000 U/L with a sensitivity of 86% and a specificity of 83%. In terms of the percentage of body area crushed, the AUC for predicting KRT was 0.907 (95% CI 0.838-0.976; p < 0.001). The optimal cut-off value was 30% with a sensitivity of 86% and a specificity of 88%. Multiple logistic regression analysis showed that each 10% increase in body area crushed (OR 4.16, 95% CI 1.58-10.93, p = 0.004) and 1 mg/dl increase in the serum phosphorus level (OR 4.19, 95% CI 1.71-10.28, p = 0.002) were significant risk factors for dialysis treatment.

CONCLUSIONS

Crush syndrome and kidney problems are common following disasters like earthquakes. Clinical and laboratory findings at admission can predict dialysis requirement in earthquake victims. While CK elevation, body area crushed percentage, and increased phosphorus level were predictive of dialysis treatment, time under the rubble was not. Even if the patients were under the rubble for a short time, acute kidney injury (AKI) may develop as a result of severe hypovolemia due to crush injuries, and patients may need KRT.

WHAT IS KNOWN

•Crush syndrome after earthquakes needs to be treated carefully in victims and can cause AKI and mortality when not treated timely and appropriately.

WHAT IS NEW

•CK level elevation, body area crushed percentage, and increased phosphorus level are predictive of dialysis treatment. •The time under the rubble may not be predictive of dialysis requirement.

Insights from the 4C-T Study suggest increased cardiovascular burden in girls with end stage kidney disease before and after kidney transplantation

Mortality in children with kidney failure is higher in girls than boys with cardiovascular complications representing the most common causes of death. Pulse wave velocity (PWV), a measure of vascular stiffness, predicts cardiovascular mortality in adults. Here, PWV in children with kidney failure undergoing kidney replacement therapy was investigated to determine sex differences and potential contributing factors. Two-hundred-thirty-five children (80 girls; 34%) undergoing transplantation (150 pre-emptive, 85 with prior dialysis) having at least one PWV measurement pre- and/or post-transplantation from a prospective cohort were analyzed. Longitudinal analyses (median/maximum follow-up time of 6/9 years) were performed for PWV z-scores (PWVz) using linear mixed regression models and further stratified by the categories of time: pre-kidney replacement therapy and post-transplantation. PWVz significantly increased by 0.094 per year and was significantly higher in girls (PWVz +0.295) compared to boys, independent of the underlying kidney disease. During pre-kidney replacement therapy, an average estimated GFR decline of 4ml/min/1.73m² per year was associated with a PWVz increase of 0.16 in girls only. Higher diastolic blood pressure and low density lipoprotein were independently associated with higher PWVz during pre-kidney replacement therapy in both sexes. In girls post-transplantation, an estimated GFR decline of 4ml/min/1.73m² per year pre-kidney replacement therapy and a longer time (over 12 months) to transplantation were significantly associated with higher PWVz of 0.22 and of 0.57, respectively. PWVz increased further after transplantation and was positively associated with time on dialysis and diastolic blood pressure in both sexes. Thus, our findings demonstrate that girls with advanced chronic kidney disease are more susceptible to develop vascular stiffening compared to boys, this difference persist after transplantation and might contribute to higher mortality rates seen in girls with kidney failure.

More than tubular dysfunction: cystinosis and kidney outcomes

BACKGROUND

Cystinosis is a lysosomal storage disease that affects many tissues. Its prognosis depends predominantly on kidney involvement. Cystinosis has three clinical forms: nephropathic infantile, nephropathic juvenile and non-nephropathic adult. Proximal tubular dysfunction is prominent in the infantile form, whereas a combination of glomerular and tubular alterations are observed in the juvenile form.

METHODS

Thirty-six children with nephropathic cystinosis were included in the study. Clinical features, molecular genetic diagnoses, and kidney outcomes of the patients were evaluated.

RESULTS

Twenty-one children (58.3%) were male. The median age at diagnosis was 18.5 months. Twenty-eight patients (77.8%) had infantile nephropathic cystinosis, while eight (22.2%) had juvenile nephropathic cystinosis. An acute rapid deterioration of the kidney function with proteinuria, hypoalbuminemia, and nephrotic syndrome, was observed in 37.5% of patients with the juvenile form. The mean estimated glomerular filtration rate (eGFR) was 82.31 ± 37.45 ml/min/1.73m² at diagnosis and 63.10 ± 54.60 ml/min/1.73m² at the last visit (p = 0.01). Six patients (16.6%) had kidney replacement therapy (KRT) at the last visit. The median age of patients with kidney failure was 122 months. Patients with a spot urine protein/creatinine ratio < 6 mg/mg at the time of diagnosis had better kidney outcomes (p = 0.01). The most common allele was c.451A>G (32.6%). The patients with the most common mutation tended to have higher mean eGFR and lower leukocyte cystine levels than patients with other mutations.

CONCLUSION

Glomerulonephritis may be a frequent finding in addition to the well-known tubular dysfunction in patients with cystinosis. Furthermore, our results highlight that the presence of severe proteinuria at the time of diagnosis is a relevant prognostic factor for kidney survival.

Active vitamin D is cardioprotective in experimental uraemia but not in children with CKD Stages 3-5

BACKGROUND

Uraemic cardiac remodelling is associated with vitamin D and Klotho deficiency, elevated fibroblast growth factor 23 (FGF23) and activation of the renin-angiotensin system (RAS). The cardioprotective properties of active vitamin D analogues in this setting are unclear.

METHODS

In rats with 5/6 nephrectomy (5/6Nx) treated with calcitriol, the cardiac phenotype and local RAS activation were investigated compared with controls. A nested case-control study was performed within the Cardiovascular Comorbidity in Children with Chronic Kidney Disease (4C) study, including children with chronic kidney disease (CKD) Stages 3-5 [estimated glomerular filtration rate (eGFR) 25 mL/min/1.73 m2] treated with and without active vitamin D. Echocardiograms, plasma FGF23 and soluble Klotho (sKlotho) were assessed at baseline and after 9 months.

RESULTS

In rats with 5/6Nx, left ventricular (LV) hypertrophy, LV fibrosis and upregulated cardiac RAS were dose-dependently attenuated by calcitriol. Calcitriol further stimulated FGF23 synthesis in bone but not in the heart, and normalized suppressed renal Klotho expression. In the 4C study cohort, treatment over a mean period of 9 months with active vitamin D was associated with increased FGF23 and phosphate and decreased sKlotho and eGFR compared with vitamin D naïve controls, whereas LV mass index did not differ between groups.

CONCLUSIONS

Active vitamin D ameliorates cardiac remodelling and normalizes renal Klotho expression in 5/6Nx rats but does not improve the cardiac phenotype in children with CKD Stages 3-5. This discrepancy may be due to further enhancement of circulating FGF23 and faster progression of CKD associated with reduced sKlotho and higher serum phosphate in vitamin D-treated patients.

CDH12 as a Candidate Gene for Kidney Injury in Posterior Urethral Valve Cases: A Genome-wide Association Study Among Patients with Obstructive Uropathies

Background

Posterior urethral valves (PUVs) and ureteropelvic junction obstruction (UPJO) are congenital obstructive uropathies that may impair kidney development.

Objective

To identify genetic variants associated with kidney injury in patients with obstructive uropathy.

Design, setting, and participants

We included 487 patients born in 1981 or later who underwent pyeloplasty or valve resection before 18 yr of age in the discovery phase, 102 PUV patients in a first replication phase, and 102 in a second replication phase.

Outcome measurements and statistical analysis

Signs of kidney injury were defined as dialysis, nephrectomy, kidney transplantation, estimated glomerular filtration rate (eGFR) <60 ml/min/1.73 m², high blood pressure, antihypertensive medication use, proteinuria, and/or one kidney functioning at <45%. We used χ² tests to calculate p values and odds ratios for >600 000 single-nucleotide polymorphisms (SNPs) in the discovery sample comparing patients with and without signs of kidney injury within 5 yr after surgery. We performed stratified analyses for PUV and UPJO and Kaplan-Meier and Cox regression analyses in the discovery and two replication samples for the associated SNPs, and RNA and protein expression analyses for the associated gene in fetal tissues.

Results and limitations

Despite the small and nonhomogeneous sample, we observed suggestive associations for six SNPs in three loci, of which rs6874819 in the CDH12 gene was the most clear (p = 7.5 × 10^–7). This SNP also seemed to be associated with time to kidney injury in the PUV discovery and replication samples. RNA expression analyses showed clear CDH12 expression in fetal kidneys, which was confirmed by protein immunolocalization.

Conclusions

This study identified CDH12 as a candidate gene for kidney injury in PUV.

Patient summary

We found that variants of the CDH12 gene increase the risk of kidney injury in patients with extra flaps of tissue in the urethra (posterior urethral valves). This is the first report on this gene in this context. Our study provides interesting new information about the pathways involved and important leads for further research for this condition.

Evaluation of phenotypic and genotypic features of children with distal kidney tubular acidosis

BACKGROUND

The present study aimed to assess genotype-phenotype correlations with long-term prognosis in children with distal kidney tubular acidosis (dKTA). The kidney function of children with dKTA could be impaired in the long-term.

METHODS

Thirty-one children with dKTA from 23 families were included in the present study. Demographic features, growth parameters, clinical manifestations, follow-up results, and genetic analysis results of the patients were recorded.

RESULTS

Eighteen children (58.1%) were male. The median age at diagnosis was 3 months. The median follow-up period was 77 months and the longest was 23.5 years. Eight (28.8%) patients had chronic kidney disease (CKD) stage 2 or 3. Three patients aged 24, 23, and 19 years had CKD stage 3 with an estimated glomerular filtration rate of 54, 57, and 48 mL/min/1.73 m², respectively. Thirteen patients had mutations in the ATP6V0A4 gene, eight had mutations in the ATP6V1B1 gene, and three had mutations in the SLC4A1 gene. There was no significant correlation between molecular diagnosis and CKD. Growth retardation with a height below a standard deviation (SD) score of - 2 was found in 14 patients (45.1%) at the time of diagnosis. The mean height SD score at the last visit was significantly higher in patients who had adequate metabolic control at > 75% of all visits as compared with that in patients who did not.

CONCLUSION

Patients with dKTA usually have a good clinical prognosis in childhood with appropriate treatment; however, dRTA is characterized by deterioration of kidney function in adulthood, particularly after puberty.

Serum indoxyl sulfate concentrations associate with progression of chronic kidney disease in children

The uremic toxins indoxyl sulfate (IS) and p-cresyl sulfate (pCS) accumulate in patients with chronic kidney disease (CKD) as a consequence of altered gut microbiota metabolism and a decline in renal excretion. Despite of solid experimental evidence for nephrotoxic effects, the impact of uremic toxins on the progression of CKD has not been investigated in representative patient cohorts. In this analysis, IS and pCS serum concentrations were measured in 604 pediatric participants (mean eGFR of 27 ± 11 ml/min/1.73m2) at enrolment into the prospective Cardiovascular Comorbidity in Children with CKD study. Associations with progression of CKD were analyzed by Kaplan-Meier analyses and Cox proportional hazard models. During a median follow up time of 2.2 years (IQR 4.3-0.8 years), the composite renal survival endpoint, defined as 50% loss of eGFR, or eGFR <10ml/min/1.73m2 or start of renal replacement therapy, was reached by 360 patients (60%). Median survival time was shorter in patients with IS and pCS levels in the highest versus lowest quartile for both IS (1.5 years, 95%CI [1.1,2.0] versus 6.0 years, 95%CI [5.0,8.4]) and pCS (1.8 years, 95%CI [1.5,2.8] versus 4.4 years, 95%CI [3.4,6.0]). Multivariable Cox regression disclosed a significant association of IS, but not pCS, with renal survival, which was independent of other risk factors including baseline eGFR, proteinuria and blood pressure. In this exploratory analysis we provide the first data showing a significant association of IS, but not pCS serum concentrations with the progression of CKD in children, independent of other known risk factors. In the absence of comorbidities, which interfere with serum levels of uremic toxins, such as diabetes, obesity and metabolic syndrome, these results highlight the important role of uremic toxins and accentuate the unmet need of effective elimination strategies to lower the uremic toxin burden and abate progression of CKD.

Discontinuation of RAAS Inhibition in Children with Advanced CKD

BACKGROUND AND OBJECTIVES

Although renin-angiotensin-aldosterone system inhibition (RAASi) is a cornerstone in the treatment of children with CKD, it is sometimes discontinued when kidney function declines. We studied the reasons of RAASi discontinuation and associations between RAASi discontinuation and important risk markers of CKD progression and on eGFR decline in the Cardiovascular Comorbidity in Children with CKD study.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

In this study, 69 children with CKD (67% male, mean age 13.7 years, mean eGFR 27 ml/min per 1.73 m²) who discontinued RAASi during prospective follow-up were included. Initial change in BP, albuminuria, and potassium after discontinuation were assessed (median time 6 months). Rate of eGFR decline (eGFR slope) during a median of 1.9 years before and 1.2 years after discontinuation were estimated using linear mixed effects modeling.

RESULTS

Physician-reported reasons for RAASi discontinuation were increase in serum creatinine, hyperkalemia, and symptomatic hypotension. After discontinuation of RAASi, BP and albuminuria increased, whereas potassium decreased. eGFR declined more rapidly after discontinuation of RAASi (-3.9 ml/min per 1.73 m² per year; 95% confidence interval, -5.1 to -2.6) compared with the slope during RAASi treatment (-1.5 ml/min per 1.73 m² per year; 95% confidence interval, -2.4 to -0.6; P=0.005). In contrast, no change in eGFR slope was observed in a matched control cohort of patients in whom RAASi was continued.

CONCLUSIONS

Discontinuation of RAASi in children with CKD is associated with an acceleration of kidney function decline, even in advanced CKD.

Association between timing of dialysis initiation and clinical outcomes in the paediatric population: an ESPN/ERA-EDTA registry study

BACKGROUND

There is no consensus regarding the timing of dialysis therapy initiation for end-stage kidney disease (ESKD) in children. As studies investigating the association between timing of dialysis initiation and clinical outcomes are lacking, we aimed to study this relationship in a cohort of European children who started maintenance dialysis treatment.

METHODS

We used data on 2963 children from 21 different countries included in the European Society of Pediatric Nephrology/European Renal Association-European Dialysis and Transplant Association Registry who started renal replacement therapy before 18 years of age between 2000 and 2014. We compared two groups according to the estimated glomerular filtration rate (eGFR) at start: eGFR ≥8 mL/min/1.73 m2 (early starters) and eGFR <8 mL/min/1.73 m2 (late starters). The primary outcomes were patient survival and access to transplantation. Secondary outcomes were growth and cardiovascular risk factors. Sensitivity analyses were performed to account for selection- and lead time-bias.

RESULTS

The median eGFR at the start of dialysis was 6.1 for late versus 10.5 mL/min/1.73 m2 for early starters. Early starters were older [median: 11.0, interquartile range (IQR): 5.7-14.5 versus 9.4, IQR: 2.6-14.1 years]. There were no differences observed between the two groups in mortality and access to transplantation at 1, 2 and 5 years of follow-up. One-year evolution of height standard deviation scores was similar among the groups, whereas hypertension was more prevalent among late initiators. Sensitivity analyses resulted in similar findings.

CONCLUSIONS

We found no evidence for a clinically relevant benefit of early start of dialysis in children with ESKD. Presence of cardiovascular risk factors, such as high blood pressure, should be taken into account when deciding to initiate or postpone dialysis in children with ESKD, as this affects the survival.

Neutral pH and low-glucose degradation product dialysis fluids induce major early alterations of the peritoneal membrane in children on peritoneal dialysis

The effect of peritoneal dialysates with low-glucose degradation products on peritoneal membrane morphology is largely unknown, with functional relevancy predominantly derived from experimental studies. To investigate this, we performed automated quantitative histomorphometry and molecular analyses on 256 standardized peritoneal and 172 omental specimens from 56 children with normal renal function, 90 children with end-stage kidney disease at time of catheter insertion, and 82 children undergoing peritoneal dialysis using dialysates with low-glucose degradation products. Follow-up biopsies were obtained from 24 children after a median peritoneal dialysis of 13 months. Prior to dialysis, mild parietal peritoneal inflammation, epithelial-mesenchymal transition and vasculopathy were present. After up to six and 12 months of peritoneal dialysis, blood microvessel density was 110 and 93% higher, endothelial surface area per peritoneal volume 137 and 95% greater, and submesothelial thickness 23 and 58% greater, respectively. Subsequent peritoneal changes were less pronounced. Mesothelial cell coverage was lower and vasculopathy advanced, whereas lymphatic vessel density was unchanged. Morphological changes were accompanied by early fibroblast activation, leukocyte and macrophage infiltration, diffuse podoplanin presence, epithelial mesenchymal transdifferentiation, and by increased proangiogenic and profibrotic cytokine abundance. These transformative changes were confirmed by intraindividual comparisons. Peritoneal microvascular density correlated with peritoneal small-molecular transport function by uni- and multivariate analysis. Thus, in children on peritoneal dialysis neutral pH dialysates containing low-glucose degradation products induce early peritoneal inflammation, fibroblast activation, epithelial-mesenchymal transition and marked angiogenesis, which determines the PD membrane transport function.

Effects of Hemodiafiltration versus Conventional Hemodialysis in Children with ESKD: The HDF, Heart and Height Study

BACKGROUND

Hypertension and cardiovascular disease are common in children undergoing dialysis. Studies suggest that hemodiafiltration (HDF) may reduce cardiovascular mortality in adults, but data for children are scarce.

METHODS

The HDF, Heart and Height study is a nonrandomized observational study comparing outcomes on conventional hemodialysis (HD) versus postdilution online HDF in children. Primary outcome measures were annualized changes in carotid intima-media thickness (cIMT) SD score and height SD score.

RESULTS

We enrolled 190 children from 28 centers; 78 on HD and 55 on HDF completed 1-year follow-up. The groups were comparable for age, dialysis vintage, access type, dialysis frequency, blood flow, and residual renal function. At 1 year, cIMT SD score increased significantly in children on HD but remained static in the HDF cohort. On propensity score analysis, HD was associated with a +0.47 higher annualized cIMT SD score compared with HDF. Height SD score increased in HDF but remained static in HD. Mean arterial pressure SD score increased with HD only. Factors associated with higher cIMT and mean arterial pressure SD-scores were HD group, higher ultrafiltration rate, and higher β2-microglobulin. The HDF cohort had lower β2-microglobulin, parathyroid hormone, and high-sensitivity C-reactive protein at 1 year; fewer headaches, dizziness, or cramps; and shorter postdialysis recovery time.

CONCLUSIONS

HDF is associated with a lack of progression in vascular measures versus progression with HD, as well as an increase in height not seen in the HD cohort. Patient-related outcomes improved among children on HDF correlating with improved BP control and clearances. Confirmation through randomized trials is required.

Low renal but high extrarenal phenotype variability in Schimke immuno-osseous dysplasia

Schimke immuno-osseous dysplasia (SIOD) is a rare multisystem disorder with early mortality and steroid-resistant nephrotic syndrome (SRNS) progressing to end-stage kidney disease. We hypothesized that next-generation gene panel sequencing may unsurface oligosymptomatic cases of SIOD with potentially milder disease courses. We analyzed the renal and extrarenal phenotypic spectrum and genotype-phenotype associations in 34 patients from 28 families, the largest SMARCAL1-associated nephropathy cohort to date. In 11 patients the diagnosis was made unsuspectedly through SRNS gene panel testing. Renal disease first manifested at median age 4.5 yrs, with focal segmental glmerulosclerosis or minimal change nephropathy on biopsy and rapid progression to end-stage kidney disease (ESKD) at median age 8.7 yrs. Whereas patients diagnosed by phenotype more frequently developed severe extrarenal complications (cerebral ischemic events, septicemia) and were more likely to die before age 10 years than patients identified by SRNS-gene panel screening (88 vs. 40%), the subgroups did not differ with respect to age at proteinuria onset and progression to ESKD. Also, 10 of 11 children diagnosed unsuspectedly by Next Generation Sequencing were small at diagnosis and all showed progressive growth failure. Severe phenotypes were usually associated with biallelic truncating mutations and milder phenotypes with biallelic missense mutations. However, no genotype-phenotype correlation was observed for the renal disease course. In conclusion, while short stature is a reliable clue to SIOD in children with SRNS, other systemic features are highly variable. Our findings support routine SMARCAL1 testing also in non-syndromic SRNS.

Metabolic acidosis is common and associates with disease progression in children with chronic kidney disease

Recent studies in adult chronic kidney disease (CKD) suggest that metabolic acidosis is associated with faster decline in estimated glomerular filtration rate (eGFR). Alkali therapies improve the course of kidney disease. Here we investigated the prevalence and determinants of abnormal serum bicarbonate values and whether metabolic acidosis may be deleterious to children with CKD. Associations between follow-up serum bicarbonate levels categorized as under 18, 18 to under 22, and 22 or more mmol/l and CKD outcomes in 704 children in the Cardiovascular Comorbidity in Children with CKD Study, a prospective cohort of pediatric patients with CKD stages 3-5, were studied. The eGFR and serum bicarbonate were measured every six months. At baseline, the median eGFR was 27 ml/min/1.73m² and median serum bicarbonate level 21 mmol/l. During a median follow-up of 3.3 years, the prevalence of metabolic acidosis (serum bicarbonate under 22 mmol/l) was 43%, 60%, and 45% in CKD stages 3, 4, and 5, respectively. In multivariable analysis, the presence of metabolic acidosis as a time-varying covariate was significantly associated with log serum parathyroid hormone through the entire follow-up, but no association with longitudinal growth was found. A total of 211 patients reached the composite endpoint (ESRD or 50% decline in eGFR). In a multivariable Cox model, children with time-varying serum bicarbonate under 18 mmol/l had a significantly higher risk of CKD progression compared to those with a serum bicarbonate of 22 or more mmol/l (adjusted hazard ratio 2.44; 95% confidence interval 1.43-4.15). Thus, metabolic acidosis is a common complication in pediatric patients with CKD and may be a risk factor for secondary hyperparathyroidism and kidney disease progression.

Infants Requiring Maintenance Dialysis: Outcomes of Hemodialysis and Peritoneal Dialysis

BACKGROUND

The impact of different dialysis modalities on clinical outcomes has not been explored in young infants with chronic kidney failure.

STUDY DESIGN

Cohort study.

SETTING & PARTICIPANTS

Data were extracted from the ESPN/ERA-EDTA Registry. This analysis included 1,063 infants 12 months or younger who initiated dialysis therapy in 1991 to 2013.

FACTOR

Type of dialysis modality.

OUTCOMES & MEASUREMENTS

Differences between infants treated with peritoneal dialysis (PD) or hemodialysis (HD) in patient survival, technique survival, and access to kidney transplantation were examined using Cox regression analysis while adjusting for age at dialysis therapy initiation, sex, underlying kidney disease, and country of residence.

RESULTS

917 infants initiated dialysis therapy on PD, and 146, on HD. Median age at dialysis therapy initiation was 4.5 (IQR, 0.7-7.9) months, and median body weight was 5.7 (IQR, 3.7-7.5) kg. Although the groups were homogeneous regarding age and sex, infants treated with PD more often had congenital anomalies of the kidney and urinary tract (CAKUT; 48% vs 27%), whereas those on HD therapy more frequently had metabolic disorders (12% vs 4%). Risk factors for death were younger age at dialysis therapy initiation (HR per each 1-month later initiation, 0.95; 95% CI, 0.90-0.97) and non-CAKUT cause of chronic kidney failure (HR, 1.49; 95% CI, 1.08-2.04). Mortality risk and likelihood of transplantation were equal in PD and HD patients, whereas HD patients had a higher risk for changing dialysis treatment (adjusted HR, 1.64; 95% CI, 1.17-2.31).

LIMITATIONS

Inability to control for unmeasured confounders not included in the Registry database and missing data (ie, comorbid conditions). Low statistical power because of relatively small number of participants.

CONCLUSIONS

Despite a widespread preconception that HD should be reserved for cases in which PD is not feasible, in Europe, we found 1 in 8 infants in need of maintenance dialysis to be initiated on HD therapy. Patient characteristics at dialysis therapy initiation, prospective survival, and time to transplantation were very similar for infants initiated on PD or HD therapy.

ADCK4-Associated Glomerulopathy Causes Adolescence-Onset FSGS

Hereditary defects of coenzyme Q10 biosynthesis cause steroid-resistant nephrotic syndrome (SRNS) as part of multiorgan involvement but may also contribute to isolated SRNS. Here, we report 26 patients from 12 families with recessive mutations in ADCK4. Mutation detection rate was 1.9% among 534 consecutively screened cases. Patients with ADCK4 mutations showed a largely renal-limited phenotype, with three subjects exhibiting occasional seizures, one subject exhibiting mild mental retardation, and one subject exhibiting retinitis pigmentosa. ADCK4 nephropathy presented during adolescence (median age, 14.1 years) with nephrotic-range proteinuria in 44% of patients and advanced CKD in 46% of patients at time of diagnosis. Renal biopsy specimens uniformly showed FSGS. Whereas 47% and 36% of patients with mutations in WT1 and NPHS2, respectively, progressed to ESRD before 10 years of age, ESRD occurred almost exclusively in the second decade of life in ADCK4 nephropathy. However, CKD progressed much faster during adolescence in ADCK4 than in WT1 and NPHS2 nephropathy, resulting in similar cumulative ESRD rates (>85% for each disorder) in the third decade of life. In conclusion, ADCK4-related glomerulopathy is an important novel differential diagnosis in adolescents with SRNS/FSGS and/or CKD of unknown origin.

Aortic Pulse Wave Velocity in Healthy Children and Adolescents: Reference Values for the Vicorder Device and Modifying Factors

BACKGROUND

Aortic pulse wave velocity (PWV), an indicator of arterial stiffness, independently predicts cardiovascular mortality risk in adults. Arterial stiffening advances with age and seems accelerated in children with certain disease conditions such as chronic kidney disease or diabetes. The Vicorder, an oscillometric device to measure PWV, has been validated in children, but reference values in a large pediatric cohort, association to carotid stiffness and influence of individual and family risk factors have not been determined.

METHODS

Pulse waves were captured in 1,003 healthy children (aged 6-18 years) in 6 centers and gender-specific reference data normalized to age/height were constructed. In 589 children carotid distensibility and intima media thickness were measured. Gestational and family history was reported.

RESULTS

PWV correlated with age (r = 0.57, P < 0.0001) with significant gender-related differences starting at age 9. Further significant correlations were seen for height, weight, body mass index, blood pressure, pulse pressure, and heart rate. Independent predictors for PWV in a multivariate regression analysis were gender, age, height, weight, mean arterial pressure, and heart rate. Risk factors for higher PWV included small for gestational age at birth, secondhand smoking, parental hypertension, and obesity. PWV showed weak correlations with 2 of the carotid distensibility measures, but not with intima media thickness.

CONCLUSION

This study defines reference values for PWV captured by the Vicorder device in children and adolescents and reveals associations with potential cardiovascular risk factors in a healthy population. Gender-specific percentiles for age/height will allow for the assessment of pediatric cohorts using this oscillometric method.

Urinary tract effects of HPSE2 mutations

Urofacial syndrome (UFS) is an autosomal recessive congenital disease featuring grimacing and incomplete bladder emptying. Mutations of HPSE2, encoding heparanase 2, a heparanase 1 inhibitor, occur in UFS, but knowledge about the HPSE2 mutation spectrum is limited. Here, seven UFS kindreds with HPSE2 mutations are presented, including one with deleted asparagine 254, suggesting a role for this amino acid, which is conserved in vertebrate orthologs. HPSE2 mutations were absent in 23 non-neurogenic neurogenic bladder probands and, of 439 families with nonsyndromic vesicoureteric reflux, only one carried a putative pathogenic HPSE2 variant. Homozygous Hpse2 mutant mouse bladders contained urine more often than did wild-type organs, phenocopying human UFS. Pelvic ganglia neural cell bodies contained heparanase 1, heparanase 2, and leucine-rich repeats and immunoglobulin-like domains-2 (LRIG2), which is mutated in certain UFS families. In conclusion, heparanase 2 is an autonomic neural protein implicated in bladder emptying, but HPSE2 variants are uncommon in urinary diseases resembling UFS.

Carotid artery intima-media thickness and distensibility in children and adolescents: reference values and role of body dimensions

Carotid intima-media thickness (cIMT) and carotid artery distensibility are reliable screening methods for vascular alterations and the assessment of cardiovascular risk in adult and pediatric cohorts. We sought to establish an international reference data set for the childhood and adolescence period and explore the impact of developmental changes in body dimensions and blood pressure (BP) on carotid wall thickness and elasticity. cIMT, the distensibility coefficient, the incremental modulus of elasticity, and the stiffness index β were assessed in 1155 children aged 6 to 18 years and sex-specific reference charts normalized to age or height were constructed from 1051 nonobese and nonhypertensive children. The role of body dimensions, BP, and family history, as well as the association between cIMT and distensibility, was investigated. cIMT increased and distensibility decreased with age, height, body mass index, and BP. A significant sex difference was apparent from the age of 15 years. Age- and height-normalized cIMT and distensibility values differed in children who are short or tall for their age. By stepwise multivariate analysis, standardized systolic BP and body mass index were independently positively associated with cIMT SD scores (SDS). Systolic BP SDS independently predicted all distensibility measures. Distensibility coefficient SDS was negatively and β SDS positively associated with cIMT SDS, whereas incremental modulus of elasticity was independent of cIMT. Morphological and functional aspects of the common carotid artery are particularly influenced by age, body dimensions, and BP. The reference charts established in this study allow to accurately compare vascular phenotypes of children with chronic conditions with those of healthy children.

Association of eNOS gene intron 4 a/b VNTR polymorphisms in children with nephrotic syndrome

To investigate the association of endothelial nitric oxide synthase gene intron 4 (eNOS4) polymorphisms with nephrotic syndrome, the eNOS4 genotypes were assessed in 161 children with nephrotic syndrome in comparison with 78 healthy subjects. We classified the children with nephritic syndrome into 2 groups: as steroid-sensitive nephrotic syndrome (SSNS) (n=125) and steroid-resistant nephrotic syndrome (SRNS) (n=36). The eNOS4 polymorphisms were analyzed by polymerase chain reaction. The frequencies of eNOS4 aa, ab and bb genotypes were 3%, 31%, and 66% in all the nephrotic syndrome groups, and 1%, 23%, and 76% in the control group (x(2)=2.87, p>0.05). In addition, the frequencies of eNOS4 aa, ab and bb genotypes were 2%, 33%, and 65% in SSNS group, and 5%, 28%, and 67% in the SRNS group (x(2)=1.13, p=0.567). The present study is the first to investigate eNOS4 gene polymorphisms in children with SSNS and SRNS. Our data show that the eNOS4 gene polymorphisms were not associated with the development, frequent relapse and response to steroid in nephritic syndrome.

The Cardiovascular Comorbidity in Children with Chronic Kidney Disease (4C) study: objectives, design, and methodology

BACKGROUND AND OBJECTIVES

Children and adolescents with chronic kidney disease (CKD) are at high risk for cardiovascular morbidity and mortality. A systemic arteriopathy and cardiomyopathy has been characterized in pediatric dialysis patients by the presence of morphologic and functional abnormalities.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

The Cardiovascular Comorbidity in Children with CKD (4C) Study is a multicenter, prospective, observational study aiming to recruit more than 600 children, aged 6 to 17 years, with initial GFR of 10 to 45 ml/min per 1.73 m(2). The prevalence, degree, and progression of cardiovascular comorbidity as well as its association with CKD progression will be explored through longitudinal follow-up. The morphology and function of the heart and large arteries will be monitored by sensitive noninvasive methods and compared with aged-matched healthy controls. Multiple clinical, anthropometric, biochemical, and pharmacologic risk factors will be monitored prospectively and related to the cardiovascular status. A whole-genome association study will be performed to identify common genetic variants associated with progression of cardiovascular alterations and/or renal failure. Monitoring will be continued as patients reach end-stage renal disease and undergo different renal replacement therapies.

RESULTS

While cardiovascular morbidity in adults is related to older age and additional risk factor load (e.g., diabetes), the role of CKD-specific factors in the initiation and progression of cardiac and vascular disease are likely to be characterized with greater sensitivity in the pediatric age group.

CONCLUSIONS

The 4C study is expected to provide innovative insight into cardiovascular and renal disease progression in CKD.

ACE Gene Polymorphism in Turkish Children with Nephrotic Syndrome

Since 1990, the role of angiotensin converting enzyme (ACE) gene polymorphism in various renal and cardiac diseases is still debated. This study comprised 71 pediatric patients with nephrotic syndrome, 47 males (66%) and 24 females (34%) with a mean age of 57.4 +/- 37.6 months, and a control group of 83 healthy males (59%) and 57 healthy females (41%) with a mean age of 505 +/- 160.5 months. The distribution of the ACE genotype in the control group was II, 11%; ID, 53%; and DD, 36%, and the nephrotic syndrome was II, 4%; ID, 78%; and DD, 18%. Angiotensin-converting enzyme genotypes were significantly different between patients and control groups (p<0.05). The study groups consisted of 52 (73%) with steroid-sensitive nephrotic syndrome (SNSS) and 19 (27%) with steroid-resistant nephrotic syndrome (SRNS). The distribution of the ACE genotype was II, 6%; ID, 75%; and DD, 19% in the SSNS population and ID, 84% and DD, 16% in the SRNS population. No statistically significant difference was found between steroid sensitivity and ACE genotypes (p=0.5). The results show that ACE I/D polymorphism does not contribute to the steroid resistance, even though this study indicates that the presence of the I/D genotype has a much higher risk--approximately 2.8 times--of having nephrotic syndrome. Further studies with a larger number of patients are needed.

Ambulatory blood pressure monitoring and serum nitric oxide concentration in type 1 diabetic children

Blood pressure can be determined more precisely with the use of 24 hours ambulatory measurement in type 1 diabetics. Nitric oxide (NO) has been suggested to be responsible for the vascular changes described in early diabetic nephropathy. We aimed to investigate serum NO concentration along with ambulatory blood pressure monitoring (ABPM) parameters in type 1 diabetic patients and to find out whether there are correlation between serum NO level and ABPM parameters. Forty type 1 diabetic subjects and 35 controls were enrolled. Diabetic subjects were grouped as microalbuminuric (n=16) and normalbuminuric (n=24). Casual and ambulatory blood pressure parameters and serum NO concentrations were measured in all study population. Microalbuminuric subjects had higher nighttime systolic blood pressure (SBP), 24 hours diastolic blood pressure (DBP) and 24 hours mean arterial pressure (MAP) than controls. Both microalbuminuric and normalbuminuric subjects had also significantly higher nighttime DBP and nighttime MAP than controls. Serum NO concentrations were higher in normalbuminuric and microalbuminuric subjects than controls. Serum NO concentrations were positively correlated with daytime DBP and MAP, nighttime SBP, DBP and MAP, and 24 hours DBP and MAP in microalbuminuric subjects. Serum NO concentrations were also positively correlated with nighttime DBP in normalbuminuric subjects. Multiple linear regression analysis revealed that serum NO(2)- + NO(3)- concentrations and 24 hours DBP were independently associated with the development of microalbuminuria. Albuminuria seems to be closely associated with serum NO concentrations and ABPM parameters in type 1 DM patients. A prospective follow-up study on diabetic patients with normo- and micro- albuminuria is needed to confirm the predictive values of increased NO concentrations and ABPM parameters on the development of albuminuria.

Comparison of direct radionuclide cystography and voiding direct cystography in the detection of vesicoureteral reflux

PURPOSE

The aim of this study is to compare the results of direct radionuclide cystography (DRNC) and voiding cystourethrography (VCUG) in a group of children with a high suspicion of vesicoureteral reflux (VUR).

METHODS

For this purpose, 25 children were studied with both VCUG and DRNC. Among 50 ureter units able to be compared 39 ureter units did not show any VUR on either study. Eleven ureter units (10 children) had VUR either on one study or on both (VCUG and DRNC). In the children who had VUR on either study, a dimercaptosuccinic acid scintigraphy (DMSA) was performed to determine their cortical function.

RESULTS

We identified the following four patterns: 1) Five ureter units (five children) read positive on DRNC who were negative on VCUG and four of these children had positive findings on DMSA; 2) Four ureter units (four children) read positive on VCUG who were negative on DRNC, and two of them had positive findings on DMSA; 3) Two ureters (one child) read positive in both studies and also had abnormal DMSA findings; 4) Thirty-nine ureter units read as negative on both studies.

CONCLUSION

Although the results of these two methods did not show a significant difference, DRNC offers a high sensitivity in the younger age group whereas VCUG seems to be more sensitive in the older age group. DRNC also offers continuous recording during the study, ease of assessment and lower radiation dose to the gonads, which makes it a preferable method for the initial diagnosis and follow-up of VUR.

Urinary annexin V in children with nephrotic syndrome: a new prognostic marker?

Annexin V has a molecular weight of 32-35 kDa and has been reported to possess anticoagulant activity, inhibition of phospholipase A(2), regulation of membrane transport, proliferation and signal transduction. It is reported that urinary annexin V concentration may be an indicator of apoptosis and acute renal injury related to the urinary protein level. The aim of this study was to define the role of urinary annexin V excretion and serum annexin V concentrations as new prognostic tools and follow-up criteria in children with steroid-sensitive (SSNS) and steroid-resistant nephrotic syndrome (SRNS). Annexin V concentrations were measured in serum and 24-h urine samples in 23 SSNS patients in both relapse and remission periods of each patient and in 22 SRNS patients and 22 healthy controls. Total protein, albumin, blood urea nitrogen (BUN), creatinine, total cholesterol concentrations, and 24-h urinary excretion of protein and creatinine were also measured in each patient. In the SRNS group, median 24-h urinary annexin V levels were significantly higher than for all other groups (5,048.8 ng/g creatinine vs. 2,839.5 ng/g creatinine in SSNS relapse group; 2,500.0 ng/g creatinine in SSNS remission group, and 2,018.3 ng/g creatinine in healthy control group). No significant correlation was found between urinary protein excretion and 24-h urinary annexin V levels in all subjects. Twenty-four-hour urinary annexin V excretion may be a predictor in children with SRNS, and it may be a prognostic marker in children with NS.

Reno-vascular hypertension in childhood: a nationwide survey

Renovascular disease accounts for 8-10% of all cases of paediatric hypertension, whereas, in adults, its incidence is approximately 1%. The Turkish Paediatric Hypertension Group aimed to create the first registry database for childhood renovascular hypertension in Turkey. Twenty of the 28 paediatric nephrology centres in Turkey responded to the survey and reported 45 patients (27 girls, 18 boys) with renovascular hypertension between 1990 and 2005. The age at presentation ranged from 20 days to 17 years. The mean blood pressure at the diagnosis was 169/110 mmHg. Chief complaints of symptomatic patients were headache (38%), seizure (18%), epistaxis (4%), growth retardation (4%), cognitive dysfunction (4%), polyuria (2%), palpitation (2%), and hemiplegia (2%). Renovascular hypertension was found incidentally in 11 children. The diagnosis of renovascular hypertension was established with conventional angiography in 39 patients, MR angiography in three, CT angiography in two, and captopril diethylene triamine penta-acetic acid (DTPA) scintigraphy in one patient. Twenty-one children had bilateral renal artery stenosis and 24 had unilateral renal artery stenosis. Of these, 14 (31%) had fibromuscular dysplasia; 12 (27%) Takayasu's arteritis; six (13%) neurofibromatosis; two (5%) Williams syndrome; one (2%) Kawasaki disease; one (2%) mid-aortic syndrome; one (2%) extrinsic compression to the renal artery, and eight (18%) unspecified bilateral renal artery stenosis. Hypertension was controlled with antihypertensive drugs in 17 patients. Percutaneous transluminal angioplasty (PTRA) or surgery had to be performed in 28 patients: PTRA in 16 patients, PTRA + surgery in one patient and surgery in 11 patients (four nephrectomies). The importance of vasculitic disease, especially Takayasu's arteritis, should not be underestimated in children with renovascular hypertension.

Ambulatory blood pressure monitoring and renal functions in children with a solitary kidney

The aim of this study is to investigate the blood pressure (BP) profile, microalbuminuria, renal functions, and relations with remaining normal kidney size in children with unilateral functioning solitary kidney (UFSK). Sixty-six children with UFSK were equally divided into three groups: unilateral renal agenesis (URA), unilateral atrophic kidney (UAK), and unilateral nephrectomy (UNP). Twenty-two age-, weight-, and height-matched healthy children were considered as a control group. The serum creatinine level and first-morning urine microalbumin and creatinine concentrations were determined by the standard methods. Also, the BP profile was determined by ambulatory blood pressure monitoring (ABPM). We found that the serum creatinine level was higher and creatinine clearance was lower in each patient groups compared to those of the control group (p < 0.05). Compared with the controls, each group of patients had mean office, 24-h, daytime, and night-time systolic and diastolic BP values similar to those of the controls (p > 0.05). An inverse correlation was found between the renal size standard deviation scores (SDS) of normal kidneys and 24-h systolic and diastolic BP load SDS in all of the patients (p < 0.05; r = -0.372, r = -0.295, respectively). The observed relationship between renal size SDS and 24-h mean arterial pressure (MAP), systolic and diastolic BP load SDS suggests that children with UFSK should be evaluated by using ABPM for the risk of hypertension.

Endothelial nitric oxide synthase gene intron 4 a/b VNTR polymorphism in children with APSGN

The role of endothelial nitric oxide synthase gene intron 4 a/b (eNOS4a/b) variable number of tandem repeats (VNTR) polymorphism in various renal diseases was investigated. We investigated whether the eNOS4a/b VNTR polymorphism is associated with susceptibility to acute poststreptococcal glomerulonephritis (APSGN) and its clinical features. Endothelial NOS4a/b VNTR polymorphism is determined by the polymerase chain reaction in 60 children with APSGN, and 66 healthy controls. The genotype distribution of eNOS4 does not differ between the patients and the controls (X(2)=5.1, p=0.079). However, the frequency of eNOS4a (eNOS4a/a and eNOS4a/b) genotype is higher in the patients than in the controls (X(2)=4.5, p=0.046). In the APSGN group we performed renal biopsy on eight patients because of nephrotic syndrome accompanies acute nephritic syndrome or glomerular filtration rate (GFR) is lower than 50% of normal, and found that to carry a/a and a/b genotypes were a significant risk factor for this type presentation (OR=17.3, 95% CI:1.95-152.67, p=0.03). Mean serum creatinine values are found statistically significantly higher in a/a and a/b genotypes when compared with b/b genotypes (p=0.022). Children carrying the "aa" and "ab" genotype or "a" allele of eNOS4 have a greater tendency to develop and clinical presentation of APSGN.

Renal amyloidosis in a child with sickle cell anemia

The kidney is frequently affected in patients with sickle cell syndrome, i.e., homozygous and heterozygous patients, with a consequently large spectrum of renal abnormalities that may range from minimal functional changes to chronic renal failure. Here, we present a 13-year-old boy with sickle cell anemia (SCA) (HbSS) who was referred to our unit with nephrotic syndrome. Renal biopsy revealed AA type amyloidosis on the basis of light microscopic findings, indicating Congo red staining and immunohistochemistry. He had neither a family history of familial Mediterranean fever (FMF) nor any complaint of recurrent abdominal pain, arthritis, and fever, but frequent painful vaso-occlusive crises. The patient was found to have no MEFV gene (Mediterranean feVer) mutations either. Painful episodic attacks might provoke recurrent acute inflammation, leading to repeated stimulation of acute phase responses and cause secondary amyloidosis. To our knowledge, this boy is the first case of SCA complicated by renal amyloidosis observed in childhood.

Intravenous pulse cyclophosphamide therapy in focal segmental glomerulosclerosis

AIMS

We herein report the results of intravenous pulse cyclophosphamide (IVCP) therapy of 5 patients with steroid-resistant focal segmental glomerulosclerosis (FSGS). All patients had been treated with oral and intravenous pulse methylprednisolone and failed to respond to steroids from onset and were considered as primary steroid-resistant. Before starting IVCP, all patients were also treated with other immunosuppressive drugs with or without steroids, but none of them responded to such therapies and no patient had any NPSH2 gene mutations.

METHODS

IVCP was given monthly at a dose of 500 mg/m2 for 6 months. At the end of 6 months, IVCP was discontinued in case there was no response. Otherwise, IVCP was continued for every 2 months. Oral prednisone was given concurrently at 60 mg/m2 daily for 6 weeks and then 40 mg/m2 on alternate days for 4 weeks. Prednisone was then tapered to 10 mg/m2 alternate days and continued during the therapy period.

RESULTS

Only 1 of these patients achieved remission after IVCP while 4 patients showed no response to IVCP. 2 patients who did not achieve remission progressed to end-stage renal disease (ESRD) and 2 others who had not been treated with cyclosporine before underwent cyclosporine therapy. None of our patients has suffered from adverse effects of IVCP.

CONCLUSION

We found that IVCP had a limited beneficial effect in treatment of steroid-resistant FSGS and it may be suggested that IVCP can be tried to treat steroid-resistant patients, also for patients with primary steroid resistance and those who do not respond to other immunosuppressive therapies.

Peritoneal clearance of biochemical markers of bone turnover in children with end stage renal failure on peritoneal dialysis

Renal osteodystrophy is one of the important complications in children with end stage renal disease. Non-invasive tools for evaluation of bone metabolism have been proposed in recent years. The aim of this study was to investigate the markers of metabolic bone disease and peritoneal clearance of these markers in children treated with continuous ambulatory peritoneal dialysis (CAPD). In this study, serum osteocalcin (OC) levels were found significantly higher in patients (107.98 +/- 99.99 ng/ml) than in the healthy control group (41.94 +/- 12.94 ng/ml; p<0.05). Mean peritoneal clearance (Clp) of OC was 0.87 +/- 0.91 ml/min. There was no correlation between serum OC and Clp-osteocalcin. There was a positive correlation between serum phosphorus (P) and OC (r=0.394, p=0.031), alkaline phosphatase (ALP) and OC (r=0.520, p=0.003), and parathyroid hormone (PTH) and OC (r=0.441, p=0.017), whereas no correlation was found between OC and calcium (Ca) and OC and magnesium (Mg). There was also a significant correlation between serum ALP and PTH (r=0.714, p=0.0001). A positive correlation was found between serum PTH and Clp of PTH (r=0.471, p=0.009). In conclusion, Clp-osteocalcin is of no interest as a non-invasive marker of metabolic bone disease in children treated with CAPD. But significant correlation between serum OC and PTH, P, and ALP shows that serum OC could be used as a valuable non-invasive biochemical marker of metabolic bone disease.

Aggressive angiomyxoma in a child with chronic renal failure

Aggressive angiomyxoma (AAM) is a rare and nonmetastasizing soft-tissue tumor predominantly found in the female pelvis and perineum. It has a high risk of local recurrence. We report the unusual case of a 15-year-old boy with an AAM presenting as a slowly enlarging scrotal mass. The patient had had chronic renal failure since 1997 and had needed hemodialysis for the previous 11 months. He presented with a 12-month history of a nontender soft mass in the right scrotum. Ultrasound examination revealed a solid mass in the scrotum. After surgical resection, pathological analysis disclosed spindle-shaped neoplastic cells widely separated by a myxoid stroma rich in collagen fibers and prominent irregularly shaped blood vessels; the histological examination confirmed an AAM.

Associated anomalies in children with congenital solitary functioning kidney

Congenital solitary functioning kidney (CSFK) is a relatively common renal malformation and in children is frequently complicated by anomalies of the ipsilateral genital organs and occasionally by anomalies of other organs. The aim of this study was to determine the incidence of associated urological, cardiac, gastrointestinal, hematological, neurological, skeletal, and other congenital malformations in children with CSFK. We retrospectively reviewed 87 consecutive cases of CSFK diagnosed at our hospital between 1995 and 2003. There were 45 boys and 42 girls, whose ages at diagnosis ranged from newborn to 16 years (mean 4.67+/-4.48 years). In all patients, CSFK was diagnosed by abdominal ultrasound and confirmed by radionuclide studies. In 46 patients (53%) the left kidney was absent, and in 41 patients (47%) the right kidney was absent. Overall associated anomalies were detected in 52 of the 87 children (60%) with CSFK. Urological anomalies were most common, with an incidence of 37% (32/87). Nonurological anomalies were detected in 38 children (44%) with CSFK; these included cardiac anomalies in 13, gastrointestinal anomalies in eight, hematological anomalies in five, neurological anomalies in three, and other organ anomalies in nine. In our study, more than half of the patients with CSFK had associated anomalies. For this reason we recommend abdominal ultrasound and voiding cystourethrogram for early recognition of urological anomalies and a careful physical examination for other organ anomalies in patients with CSFK.

Mitral annular calcification and brown tumor of the rib in a child with chronic renal failure

Mitral annular calcification and liquefaction necrosis of this lesion mimicking intracardiac tumor because of secondary hyperparathyroidism have been described in adult patients with chronic renal failure, but have not been reported in children. Chronic renal failure is one of the predisposing factors of this condition. We report the case of a 13-year-old patient with continuous ambulatory peritoneal dialysis with severe hyperparathyroidism who was found to have intracardiac and rib lesions considered to be brown tumors.

Glycosaminoglycan excretion in children with nephrotic syndrome

Although most childhood nephrotic syndromes respond to steroid treatment, steroid resistant nephrotic syndrome (SRNS) is also common and is particularly difficult to treat. This study investigated the role of glycosaminoglycans (GAG) in the pathogenesis and clinical course of nephrotic syndrome in children. Thirty-four children (21 males and 13 females, mean age 3.7+/-1.6 years) with steroid-sensitive nephrotic syndrome and 20 children with steroid-resistant nephrotic syndrome (12 males and 8 females, mean age 10.9+/-3.8 years; of the twenty, four had primary SRNS (FSGS) and the others had secondary SRNS) were included the study. Mean urine levels of GAG relative to creatinine (U(GAG)/U(Cr)) in patients with SRNS (n=20, 113.01+/-78.46 mg g(-1) Cr) and in patients experiencing the nephrotic period of steroid-sensitive nephrotic syndrome (n=34, 132.15+/-101.55 mg g(-1) Cr) were both significantly higher than mean U(GAG)/U(Cr) for control subjects (n=30, 51.83+/-47.66 mg g(-1) Cr) (P<0.01 for both). Patients excreted significantly more GAG during the nephrotic period of steroid-sensitive nephrotic syndrome than during remission (132.15+/-101.55 vs 39.11+/-42.73 mg g(-1) Cr, respectively; P<0.01). There was, however, no significant difference between U(GAG)/U(Cr) for patients with steroid-resistant nephrotic syndrome and U(GAG)/U(Cr) in the nephrotic period of steroid-sensitive nephrotic syndrome. Urine GAG excretion correlated significantly with the severity of proteinuria. The results suggest that GAG play a significant role in the pathogenesis of nephrotic syndrome but that GAG excretion is not a marker for response to steroid treatment in pediatric patients with this condition.

A child with Beckwith-Wiedemann syndrome and posterior urethral valves

Beckwith-Wiedemann syndrome is a somatic overgrowth syndrome characterized by a variable incidence of congenital anomalies, including hemihypertrophy, omphalocele, macroglossia and renal malformations. We report a child with Beckwith-Wiedemann syndrome and posterior urethral valves. Urethral valve resection was successfully performed under general anesthesia after voiding cystourethrography. This is the first report of Beckwith-Wiedemann syndrome associated with posterior urethral valves.

Mycophenolate mofetil in children with multidrug-resistant nephrotic syndrome

AIM

The aim of the present study is to report our clinical experiences with MMF in problematic children with chronic glomerulonephritis resistant to corticosteroids and/or other immunosuppressive drugs.

PATIENTS AND METHODS

Ten patients with chronic glomerulonephritis resistant to treatment with corticosteroids and other immunosuppressive drugs were treated with mycophenolate mofetil (MMF). Causes of chronic glomerulonephritis were mesangial proliferative glomerulonephritis (4), membranoproliferative glomerulonephritis (3), chronic sclerosing glomerulonephritis (1), focal segmental glomerulosclerosis (1), diffuse endo- and extracapillary proliferative glomerulonephritis (1). MMF 15 mg/kg was used in combination with low-dose corticosteroids and angiotensin-converting enzyme inhibitors.

RESULTS

During 24 weeks of MMF therapy, no significant changes were detected in mean serum creatinine, albumin and proteinuria. Severe leukopenia was seen in 1 patient. Additional adverse effects, including nausea and diarrhea, were observed in another patient when the dosage was increased to 20 mg/kg per day. During MMF treatment proteinuria decreased slightly without remission in 6 of 10 patients.

CONCLUSION

Further data and clinical trials are needed to evaluate the possible role of MMF in the treatment of chronic glomerulonephritis of similar etiologies in pediatric patients.

Urinary nephrocalcin excretion in children with urolithiasis

The aim of this study was to investigate the role of nephrocalcin in childhood urolithiasis. Forty-one patients with urinary stones and 25 age- and sex-matched healthy controls were admitted to the study. Blood and timed urine samples were taken from both patient and control groups for biochemical analysis. Serum and urine creatinine (Cr) and urinary nephrocalcin (NC) were measured. NC excretion was expressed as a NC/Cr (mg/g) ratio. NC-PreA/Cr and NC-D/Cr ratios were found to be significantly higher in patients than in the control group. No statistically significant differences were found in NC-A/Cr, NC-B/Cr, NC-C/Cr ratios between the patient and control groups. The high NC-PreA/Cr ratio (p = 0.012) observed in stone-forming patients indicates that this ratio may also be an important stimulatory factor for urinary stone disease.

Effect of the peritoneal dialysis prescription on pentosidine in children

Enhanced formation of advanced glycation end products (AGEs) by peritoneal dialysate containing high dextrose concentrations has been implicated as a source of peritoneal membrane toxicity and loss of viability in patients treated with peritoneal dialysis (PD). The goal of this project was to elucidate the relationship between the structurally defined AGE pentosidine accumulation on peritoneal and plasma proteins and peritoneal membrane function, and to identify clinical factors leading to alterations in these parameters. The study comprised 27 pediatric patients (14 continuous ambulatory PD, 13 chronic cycling PD) on PD for a mean duration of 37.0+/-22.8 months (range 1-120 months) and with a mean age of 13.3+/-4.4 years (range 2.4-20 years). The pentosidine contents of plasma and peritoneal proteins were significantly lower in patients with residual renal function than in patients who were anuric (plasma pentosidine 11.2+/-8.8 vs. 24.1+/-16.6, P=0.02, respectively, peritoneal pentosidine 14.9+/-11.9 vs. 31.1+/-3.7, P=0.01, respectively). There was no effect of treatment modality on plasma pentosidine (18.1+/-11.2, 18.8+/-19.3, CAPD vs. CCPD, P>0.05) or peritoneal pentosidine content (24.1+/-14.1, 24.9+/-19.6, CAPD vs. CCPD, P>0.05). There was no evidence that increased levels of pentosidine on peritoneal proteins reflect or affect peritoneal membrane function in these patients. Furthermore, there was no effect of peritonitis on the pentosidine content of peritoneal proteins or peritoneal function as measured by peritoneal equilibration test. In conclusion, PD represents a well-tolerated therapy in children with no evidence that current practice causes changes in peritoneal membrane function, or in the peritoneal clearance of plasma or peritoneal proteins rich in pentosidine.

Comparison of mycophenolate mofetil and azathioprine in obstructive nephropathy

The effect of mycophenolate mofetil (MMF) and azathioprine (AZA) in reducing renal interstitial fibrosis in rats with unilateral ureteral obstruction (UUO) was studied. Fifty-nine rats with surgically induced UUO received oral MMF (n=19), AZA (n=19), or no treatment (n=21). The obstructed kidneys were analyzed by histology and morphometry on days 21 and 60 post UUO. Fibronectin- and collagen-stained areas were significantly lower in both treatment groups when compared with the control group 21 days post surgery. Transforming growth factor (TGF)-beta expression was significantly lower in the MMF-treated group than in the AZA-treated (P<0.01) and the control (P<0.001) groups. There was no significant difference in TGF-beta expression between the AZA-treated and the control groups 21 days post surgery (P>0.05). No significant difference was found in TGF-beta and fibronectin expression between treated and untreated groups on the 60th day post surgery. However, collagen expression was significantly lower in both treated groups than in the untreated group on the 60th day (P<0.005). We observed that MMF is more effective in preventing fibrosis than AZA in the UUO model in the short term; however, there is a less significant anti-fibrotic effect of these drugs in long-term than in short-term obstruction.

Natural coagulation inhibitors (protein C, protein S, antithrombin) in patients with sickle cell anemia in a steady state

BACKGROUND

Patients with sickle cell anemia (SCA) run the risk of having decreased levels of natural coagulation inhibitors. This may be due to either hemostatic abnormalities or hepatic dysfunction. This study is designed to evaluate coagulation profiles of patients with SCA in a steady state and to determine whether hypercoagulable state is present or not.

METHODS

Seventeen children with SCA in a steady state were included in this study. The routine hematological evaluation was done with a coulter-counter. Reticulocyte percentage and blood coagulation tests were also determined. The coagulation inhibitors such as protein C (as activated partial thromboplastine time prolongation time), protein S (as Factor V inhibition) and antithrombin (colorimetric assay) were measured in all cases.

RESULTS

In the coagulation profile, mean euglobuline lysis time and mean fibrin degradation product levels were both significantly higher in the patient group than in the control group (P<0.05), although other parameters were within normal limits. The values for aspartate aminotransferase (AST), alanine aminotransferase (ALT) and indirect reacting bilirubin were significantly higher in the patient group than in the control group (P<0.001, P<0.005, P<0.0001, respectively). The serum protein levels were normal. Mean factor V level was significantly lower and mean factor VIII level was found significantly higher in the patient group than in the control group (P<0.05 and P<0.005, respectively). Protein C and AT levels were lower in patients with SCA than in control subjects (P<0.001). Protein S levels were also lower in the patient group than in the control group, but the difference between the two groups was not significant (P>0.05).

CONCLUSION

It is indicated that antithrombotic functions of patients with SCA are handicapped even in a steady state; and both hemostatic abnormalities and hepatic dysfunction contribute to low levels of natural coagulation inhibitors.