Antibiotic Prophylaxis in Infants with Grade III, IV, or V Vesicoureteral Reflux.

BACKGROUND: The efficacy of continuous antibiotic prophylaxis in preventing urinary tract infection (UTI) in infants with grade III, IV, or V vesicoureteral reflux is controversial. METHODS: In this investigator-initiated, randomized, open-label trial performed in 39 European centers, we randomly assigned infants 1 to 5 months of age with grade III, IV, or V vesicoureteral reflux and no previous UTIs to receive continuous antibiotic prophylaxis (prophylaxis group) or no treatment (untreated group) for 24 months. The primary outcome was the occurrence of the first UTI during the trial period. Secondary outcomes included new kidney scarring and the estimated glomerular filtration rate (GFR) at 24 months. RESULTS: A total of 292 participants underwent randomization (146 per group). Approximately 75% of the participants were male; the median age was 3 months, and 235 participants (80.5%) had grade IV or V vesicoureteral reflux. In the intention-to-treat analysis, a first UTI occurred in 31 participants (21.2%) in the prophylaxis group and in 52 participants (35.6%) in the untreated group (hazard ratio, 0.55; 95% confidence interval [CI], 0.35 to 0.86; P = 0.008); the number needed to treat for 2 years to prevent one UTI was 7 children (95% CI, 4 to 29). Among untreated participants, 64.4% had no UTI during the trial. The incidence of new kidney scars and the estimated GFR at 24 months did not differ substantially between the two groups. Pseudomonas species, other non-Escherichia coli organisms, and antibiotic resistance were more common in UTI isolates obtained from participants in the prophylaxis group than in isolates obtained from those in the untreated group. Serious adverse events were similar in the two groups. CONCLUSIONS: In infants with grade III, IV, or V vesicoureteral reflux and no previous UTIs, continuous antibiotic prophylaxis provided a small but significant benefit in preventing a first UTI despite an increased occurrence of non-E. coli organisms and antibiotic resistance. (Funded by the Italian Ministry of Health and others; PREDICT ClinicalTrials.gov number, NCT02021006; EudraCT number, 2013-000309-21.).

Urinary DKK3 as a biomarker for short-term kidney function decline in children with chronic kidney disease: an observational cohort study.

BACKGROUND: Childhood-onset chronic kidney disease is a progressive condition that can have a major effect on life expectancy and quality. We evaluated the usefulness of the kidney tubular cell stress marker urinary Dickkopf-related protein 3 (DKK3) in determining the short-term risk of chronic kidney disease progression in children and identifying those who will benefit from specific nephroprotective interventions. METHODS: In this observational cohort study, we assessed the association between urinary DKK3 and the combined kidney endpoint (ie, the composite of 50% reduction of the estimated glomerular filtration rate [eGFR] or progression to end-stage kidney disease) or the risk of kidney replacement therapy (ie, dialysis or transplantation), and the interaction of the combined kidney endpoint with intensified blood pressure reduction in the randomised controlled ESCAPE trial. Moreover, urinary DKK3 and eGFR were quantified in children aged 3-18 years with chronic kidney disease and urine samples available enrolled in the prospective multicentre ESCAPE (NCT00221845; derivation cohort) and 4C (NCT01046448; validation cohort) studies at baseline and at 6-monthly follow-up visits. Analyses were adjusted for age, sex, hypertension, systolic blood pressure SD score (SDS), BMI SDS, albuminuria, and eGFR. FINDINGS: 659 children were included in the analysis (231 from ESCAPE and 428 from 4C), with 1173 half-year blocks in ESCAPE and 2762 in 4C. In both cohorts, urinary DKK3 above the median (ie, >1689 pg/mg creatinine) was associated with significantly greater 6-month eGFR decline than with urinary DKK3 at or below the median (-5·6% [95% CI -8·6 to -2·7] vs 1·0% [-1·9 to 3·9], p<0·0001, in ESCAPE; -6·2% [-7·3 to -5·0] vs -1·5% [-2·9 to -0·1], p<0·0001, in 4C), independently of diagnosis, eGFR, and albuminuria. In ESCAPE, the beneficial effect of intensified blood pressure control was limited to children with urinary DKK3 higher than 1689 pg/mg creatinine, in terms of the combined kidney endpoint (HR 0·27 [95% CI 0·14 to 0·55], p=0·0003, number needed to treat 4·0 [95% CI 3·7 to 4·4] vs 250·0 [66·9 to ∞]) and the need for kidney replacement therapy (HR 0·33 [0·13 to 0·85], p=0·021, number needed to treat 6·7 [6·1 to 7·2] vs 31·0 [27·4 to 35·9]). In 4C, inhibition of the renin-angiotensin-aldosterone system resulted in significantly lower urinary DKK3 concentrations (least-squares mean 12 235 pg/mg creatinine [95% CI 10 036 to 14 433] in patients not on angiotensin-converting enzyme inhibitors or angiotensin 2 receptor blockers vs 6861 pg/mg creatinine [5616 to 8106] in those taking angiotensin-converting enzyme inhibitors or angiotensin 2 receptor blockers, p<0·0001). INTERPRETATION: Urinary DKK3 indicates short-term risk of declining kidney function in children with chronic kidney disease and might allow a personalised medicine approach by identifying those who benefit from pharmacological nephroprotection, such as intensified blood pressure lowering. FUNDING: None.

Low-Dose Antibiotic Prophylaxis Induces Rapid Modifications of the Gut Microbiota in Infants With Vesicoureteral Reflux.

Background and Objectives: Maturation of the gut microbiota (GM) in infants is critically affected by environmental factors, with potential long-lasting clinical consequences. Continuous low-dose antibiotic prophylaxis (CAP) is the standard of care for children with vesicoureteral reflux (VUR), in order to prevent recurrent urinary tract infections. We aimed to assess short-term GM modifications induced by CAP in infants. Methods: We analyzed the GM structure in 87 infants (aged 1-5 months) with high-grade VUR, previously exposed or naïve to CAP. Microbial DNA was extracted from stool samples. GM profiling was achieved by 16S rRNA gene-based next-generation sequencing. Fecal levels of short- and branched-chain fatty acids were also assessed. Results: 36/87 patients had been taking daily CAP for a median time of 47 days, while 51/87 had not. In all patients, the GM was predominantly composed by Bifidobacteriaceae and Enterobacteriaceae. Subgroup comparative analysis revealed alterations in the GM composition of CAP-exposed infants at phylum, family and genus level. CAP-exposed GM was enriched in members of Enterobacteriaceae and Bacteroidetes, especially in the genera Bacteroides and Parabacteroides, and showed a trend toward increased Klebsiella, often associated with antibiotic resistance. In contrast, the GM of non-CAP children was mostly enriched in Bifidobacterium. No differences were found in fatty acid levels. Conclusions: In infants with VUR, even a short exposure to CAP definitely alters the GM composition, with increased relative abundance of opportunistic pathogens and decreased proportions of health-promoting taxa. Early low-dose antibiotic exposure might bear potential long-term clinical risks.

Genetic loci associated with renal function measures and chronic kidney disease in children: the Pediatric Investigation for Genetic Factors Linked with Renal Progression Consortium.

BACKGROUND: Chronic kidney disease (CKD) in children is characterized by rapid progression and a high incidence of end-stage renal disease and therefore constitutes an important health problem. While unbiased genetic screens have identified common risk variants influencing renal function and CKD in adults, the presence and identity of such variants in pediatric CKD are unknown. METHODS: The international Pediatric Investigation for Genetic Factors Linked with Renal Progression (PediGFR) Consortium comprises three pediatric CKD cohorts: Chronic Kidney Disease in Children (CKiD), Effect of Strict Blood Pressure Control and ACE Inhibition on the Progression of CRF in Pediatric Patients (ESCAPE) and Cardiovascular Comorbidity in Children with CKD (4C). Clean genotype data from > 10 million genotyped or imputed single-nucleotide polymorphisms (SNPs) were available for 1136 patients with measurements of serum creatinine at study enrollment. Genome-wide association studies were conducted to relate the SNPs to creatinine-based estimated glomerular filtration rate (eGFR crea) and proteinuria (urinary albumin- or protein-to-creatinine ratio ≥ 300 and ≥ 500 mg/g, respectively). In addition, European-ancestry PediGFR patients (cases) were compared with 1347 European-ancestry children without kidney disease (controls) to identify genetic variants associated with the presence of CKD. RESULTS: SNPs with suggestive association P-values < 1 × 10(-5) were identified in 10 regions for eGFR crea, four regions for proteinuria and six regions for CKD including some plausible biological candidates. No SNP was associated at genome-wide significance (P < 5 × 10(-8)). Investigation of the candidate genes for proteinuria in adults from the general population provided support for a region on chromosome 15 near RSL24D1/UNC13C/RAB27A. Conversely, targeted investigation of genes harboring GFR-associated variants in adults from the general population did not reveal significantly associated SNPs in children with CKD. CONCLUSIONS: Our findings suggest that larger collaborative efforts will be needed to draw reliable conclusions about the presence and identity of common variants associated with eGFR, proteinuria and CKD in pediatric populations.

Face-to-face Sun Protection Training and Text Messages Improve Sun Protection Behaviour in Adolescent Organ Transplant Recipients: HIPPOlino Feasibility Study.

Adolescent organ transplant recipients have an increased risk of developing skin cancer. The aim of this study was to evaluate the technical feasibility and acceptability of short messaging service-based sun protection recommendations for adolescent patients. Sun-protective knowledge and behaviour were also evaluated using standardized questionnaires and telephone interviews. Twenty-six organ transplant recipients aged 13-22 years participated in face-to-face sun protection training. Subsequently, participants received sun protection reminders via text messages for 4 weeks. Of the participants 95% reported that they checked text messages on a regular basis. Of the 26 organ transplant recipients 19 completed questionnaires before sun protection training and 4 weeks later; 16% (3/19) knew the meaning of the UV-index before training. After training, 74% (14/19) remembered that the term UV-index describes the maximum daily level of local UV radiation. Text message-based sun protection recommendations are well accepted and technically feasible in adolescent organ transplant recipients.

Long-term growth hormone treatment in short children with CKD does not accelerate decline of renal function: results from the KIGS registry and ESCAPE trial.

BACKGROUND: Recombinant human (rh) growth hormone (GH) raises the glomerular filtration rate (GFR) in healthy individuals. Concern has been raised that long-term rhGH treatment in short children with chronic kidney disease (CKD) may accelerate the progression of CKD via induction of glomerular hyperfiltration. PATIENTS AND METHODS: We compared the decline in GFR in children with CKD enrolled in two large clinical studies with (KIGS registry) and without (ESCAPE trial) concomitant rhGH treatment and followed for up to 10 years. Estimated GFR (eGFR) was determined at yearly intervals. The annual decline in eGFR was analyzed cross-sectionally for up to 10 years and longitudinally for 5 years. RESULTS: In the KIGS registry 367 patients with CKD stages II-IV (mean age 8.0 years; 72% boys; mean eGFR 38.4 ml/min/1.73 m(2)) were treated with 0.33 mg rhGH/kg per week for at least 1 year. In the ESCAPE trial 274 non-rhGH-treated patients with CKD stages II-IV (mean age 11.6 years; 61% boys; mean GFR 47.3 ml/min/1.73 m(2)) were followed for at least 1 year. At the 5-year follow-up, the mean loss of eGFR in the KIGS children receiving continuous rhGH treatment (n = 97) did not differ significantly from that in the controls (n = 113) in the ESCAPE trial (-5.8 vs. -8.6 ml/5 years, respectively; p = 0.17). Absolute height and eGFR at baseline were significant correlates of the annual eGFR loss (model R (2) =0.121). CONCLUSIONS: Long-term rhGH-treatment does not accelerate the decline in GFR in short children with CKD. Height and baseline eGFR are significant predictors of the loss of GFR in CKD patients.

Pathogens causing urinary tract infections in infants: a European overview by the ESCAPE study group.

UNLABELLED: Knowledge of the distribution spectrum of causative organisms and their resistance patterns has become a core requirement for the rational and effective management of urinary tract infections. In the context of a prospective trial on the use of antibiotic prophylaxis in infants with underling kidney malformations, we conducted an online survey among paediatric nephrologists on positive urine cultures (July 2010-June 2012) from both hospitalized and non-hospitalized infants under 24 months of age. We collected 4745 urine cultures (UCs) at 18 units in 10 European countries. Escherichia coli was the most frequent bacterium isolated from UCs; however, in 10/16 hospitals and in 6/15 community settings, E. coli was isolated in less than 50% of the total positive UCs. Other bacterial strains were Klebsiella, Enterococcus, Proteus and Pseudomonas not only from hospital settings. E. coli showed a high resistance to amoxicillin and trimethoprim and variable to cephalosporin. Nitrofurantoin had a good rate of efficacy, with 11/16 hospitals and 11/14 community settings reporting a resistance lower than 5%. CONCLUSION: E. coli is the most common organism causing UTIs in infants; however, other bacterial strains are frequently isolated. As a result, antibiotic prophylaxis should be more elastic and adaptable over time in order to guarantee maximum efficacy.

Height gain in Ullrich-Turner syndrome after early and late growth hormone treatment start: results from a large retrospective German study and potential basis for an individualized treatment approach.

BACKGROUND: Ullrich-Turner syndrome (UTS) girls often present with short stature in adolescence to the endocrinologist when the efficacy of growth hormone (GH) to improve growth remains unknown and parameters to estimate individual GH responsiveness have yet to be determined. OBJECTIVE: Retrospective evaluation of adult height (AH) and predicted adult height at GH start (descriptive model of Ranke, Model PredAH) in early and late GH-treated German UTS patients. SUBJECTS/METHODS: 313 patients treated with GH, early [chronological age (CA) at GH start <12 years, n = 259] or late (CA at GH start ≥12 years, n = 54) who reached AH were selected from KIGS (Pfizer International Growth Database). RESULTS: AH (152.5 ± 5.9 vs. 151.1 ± 5.4 cm, p = n.s.) after GH treatment for 7.5 ± 2.12 years (GH start early) and for 5.2 ± 1.2 years (GH start late) were similar (p = n.s.) as Model PredAH (155.7 ± 4.8 vs. 154.7 ± 4.8 cm; p = n.s.) but higher (p < 0.001) than projected adult height (Ranke, ProjAH; 148.2 ± 5.5 vs. 145.2 ± 6.7 cm; p = 0.001). Total height gain over ProjAH was 4.3 ± 4.6 cm (GH start early) and 5.8 ± 4.7 cm (GH start late, p = 0.021), respectively. CONCLUSIONS: GH may improve AH in UTS patients even when started late. The individual growth response could be estimated by the descriptive Model PredAH independent of age at treatment start.

Growth hormone treatment after renal transplantation: a promising but underused chance to improve growth.

Growth retardation remains a clinical problem in children with chronic kidney disease (CKD) prior to and during end-stage renal disease. The growth of approximately 40 % of children on dialysis is stunted. Even so, growth hormone treatment (GH) is not used in the majority of small children prior to transplantation. Also, GH is effective in improving growth after transplantation, but again, it is only rarely used in this situation mainly for fear of triggering rejection episodes. In controlled studies, the number of patients who developed rejection episodes with GH was no greater than the number in untreated controls. However, patients with prior frequent rejection episodes developed further repeated subsequent rejection episodes. Many patients with repeated rejection episodes before GH treatment have reduced renal function and are expected to proceed to dialysis or retransplantation. We believe that in these patients, early individual decisions for or against GH treatment should be made as soon as other treatment strategies, such as steroid withdrawal, have failed or are not indicated. Decisions for GH treatment at a later pubertal age come too late for significant growth response and/or improvement of final height.

Mineral and bone disorders in children with chronic kidney disease.

As children with chronic kidney disease (CKD) have a long lifespan, optimal control of bone and mineral homeostasis is essential not only for the prevention of debilitating skeletal complications and for achieving adequate growth but also for preserving long-term cardiovascular health. As the growing skeleton is highly dynamic and at particular risk of deterioration, close control of bone and mineral homeostasis is required in children with CKD. However, assessment of bone disease is hampered by the limited validity of biochemical parameters-major controversy exists on key issues such as parathyroid hormone target ranges and the lack of useful imaging techniques. The role of newly discovered factors in bone and mineral homeostasis, such as fibroblast growth factor 23, is not yet established. Even though scientific evidence is limited in children with CKD, ergocalciferol or cholecalciferol supplementation and the use of calcium-free phosphate binders is recommended. The new drug cinacalcet is highly promising; however, pediatric experience is still limited to observational data and the effect of cinacalcet on longitudinal growth and pubertal development is unknown. Randomized, controlled trials are underway, including studies of cinacalcet pharmacokinetics and pharmacodynamics in infants.

Different relationships between the first 2 years on growth hormone treatment and the d3-growth hormone receptor polymorphism in short small-for-gestational-age (SGA) children.

BACKGROUND: There has been controversy in recent years on whether the d3 polymorphism of the GH receptor is associated with a better growth response to GH in idiopathic short children born small for gestational age (SGA). METHODS: In this prospective study, we evaluated exon 3-GHR polymorphisms in 142 (62 f, 80 m) short prepubertal children born SGA (birth length and/or weight of ≤-2 SD for GA) and treated with rhGH (mean dose of 0·30 mg/kg/week) in 24 centres in Germany. A growth prediction for the first year of therapy was calculated for each child according to Ranke and co-workers. The index of responsiveness (IOR) was calculated by dividing the response (observed growth minus predicted growth) by the standard error of the prediction. All analyses were performed in one centre on samples collected and shipped on filter paper. The DNA fragment containing or missing exon 3 of the GHR was amplified by multiplex PCR. RESULTS: The fl-GHR isoform was most common with a frequency of 47·8%, followed by the d3/fl isoform with 38% and the d3-GHR isoform with 14·2%. There were no significant differences regarding gestational age, birth weight and birth length, mid parental height-SDS, chronological age at start of therapy, height-SDS, BMI-SDS, height velocity and GH dose between the different subgroups according to the genotype. After the first treatment year, height (H)-SDS (P < 0·05), height velocity (HV) (P < 0·01), HV-SDS (P < 0·001) and delta-H-SDS (P < 0·05) were significantly higher in patients with d3-GHR than in those with fl-GHR. The mean IOR was above 0 in children with at least one d3 allele, and highest, with 0·54, in those with the d3-GHR isoform. After the second year on GH, no differences between the different GHR-isoforms were found. CONCLUSIONS: According to our results, the exon 3-deleted GHR explains the better growth response to GH only for the first and not for the second year.

Growth and body composition in very young SGA children.

Infants with a very low birth weight are at risk of a reduced number of nephrons predisposing to kidney disorder, hypertension, and metabolic syndrome. Approximately 3% of infants are born small for gestational age (SGA), defined as birth weight and/or length at least 2 SD below the mean for gestational age (GA), independently of whether these children are born prematurely or at term. About 10% of these children do not show postnatal catch-up growth and remain of short stature during childhood. Most of these infants are not growth hormone (GH)-deficient, but may have GH resistance. Although GH-resistant, the majority of patients benefit from GH therapy, normalize height during childhood, maintain a normal growth velocity during puberty, and attain a normal adult height. To date, GH has been shown to be safe and no significant adverse effects have been demonstrated. Children with congenital chronic kidney disease (CKD) are born with subnormal birth weight and length and about 25% are born SGA. Shortness and need for GH treatment is highly correlated with weight at birth and gestational age. Primary renal disorders modify the response to GH treatment. Analysis of whether SGA is an additional risk factor for CKD regarding the development of hypertension, metabolic syndrome and cardiovascular complications is required.

Limitations of dual x-ray absorptiometry in children with chronic kidney disease.

Dual x-ray absorptiometry (DXA) is the most widely used densitometric method for diagnosing osteoporosis in adults. It has also been widely adopted as a diagnostic tool in the pediatric population. The most significant limitation of DXA is its reliance on areal rather than volumetric bone mineral density (BMD), which results in an artificial underestimation of bone density in short people. Poor longitudinal growth, however, is an eminent problem in children with chronic kidney disease (CKD). There is also no evidence in children that areal BMD is predictive of future fracture risk, which is the traditional rationale for measuring BMD in children with CKD. Therefore, the Kidney Disease Outcomes Quality Initiative guidelines and the current position of the International Society for Clinical Densitometry (ISCD) on pediatric patients, both of which are presented in this issue of Pediatric Nephrology, do not recommend the use of DXA in children with CKD. To date, there is no consensus on the best method to assess the degree of renal osteodystrophy in this patient population, and further collaborative efforts to correlate densitometric findings with clinical outcomes are warranted.

Predicting the response to growth hormone treatment in short children with chronic kidney disease.

CONTEXT: Short stature in children with chronic kidney disease (CKD) is due to various underlying congenital or acquired renal disorders resulting in variable impairment of renal function and variable response to GH treatment. OBJECTIVE: It was the aim to develop a mathematical model that allows the prediction of the individual growth response and to identify nonresponders. DESIGN: Data from 208 prepubertal children on conservative or dialysis treatment in a large pharmaco-epidemiological survey, the KIGS (Pfizer International Growth Database), were used for the model and data from 67 similar CKD patients registered at the Dutch Growth Research Foundation for validation. RESULTS: Annualized height velocity (centimeters per year) during the first year of GH treatment was best predicted by age at start, weight sd score, underlying renal disorder (hereditary kidney disorder), glomerular filtration rate (at baseline), and GH dosage. Using these parameters, the final model explained 37% of the overall variability of growth response. Standard error of the estimates was 1.6 cm. Age was the most important predictor of growth response (20.3% of variability) followed by weight sd score at start, and 27.2% of the variability of the second-year response could be predicted by the first-year response and glomerular filtration rate. Nonresponders of the validation group could be correctly identified. CONCLUSION: Based on simple clinical variables, a robust prediction model was developed that provides realistic expectations of individual growth response to GH in short children with CKD. The model will help in identifying nonresponders and to tailor treatment strategies.

Strict blood-pressure control and progression of renal failure in children.

BACKGROUND: Although inhibition of the renin-angiotensin system delays the progression of renal failure in adults with chronic kidney disease, the blood-pressure target for optimal renal protection is controversial. We assessed the long-term renoprotective effect of intensified blood-pressure control among children who were receiving a fixed high dose of an angiotensin-converting-enzyme (ACE) inhibitor. METHODS: After a 6-month run-in period, 385 children, 3 to 18 years of age, with chronic kidney disease (glomerular filtration rate of 15 to 80 ml per minute per 1.73 m(2) of body-surface area) received ramipril at a dose of 6 mg per square meter of body-surface area per day. Patients were randomly assigned to intensified blood-pressure control (with a target 24-hour mean arterial pressure below the 50th percentile) or conventional blood-pressure control (mean arterial pressure in the 50th to 95th percentile), achieved by the addition of antihypertensive therapy that does not target the renin-angiotensin system; patients were followed for 5 years. The primary end point was the time to a decline of 50% in the glomerular filtration rate or progression to end-stage renal disease. Secondary end points included changes in blood pressure, glomerular filtration rate, and urinary protein excretion. RESULTS: A total of 29.9% of the patients in the group that received intensified blood-pressure control reached the primary end point, as assessed by means of a Kaplan-Meier analysis, as compared with 41.7% in the group that received conventional blood-pressure control (hazard ratio, 0.65; confidence interval, 0.44 to 0.94; P=0.02). The two groups did not differ significantly with respect to the type or incidence of adverse events or the cumulative rates of withdrawal from the study (28.0% vs. 26.5%). Proteinuria gradually rebounded during ongoing ACE inhibition after an initial 50% decrease, despite persistently good blood-pressure control. Achievement of blood-pressure targets and a decrease in proteinuria were significant independent predictors of delayed progression of renal disease. CONCLUSIONS: Intensified blood-pressure control, with target 24-hour blood-pressure levels in the low range of normal, confers a substantial benefit with respect to renal function among children with chronic kidney disease. Reappearance of proteinuria after initial successful pharmacologic blood-pressure control is common among children who are receiving long-term ACE inhibition. (ClinicalTrials.gov number, NCT00221845.)

Is the response to growth hormone in short children born small for gestational age dependent on genetic or maternal factors?

BACKGROUND/AIMS: We investigated whether genetic or maternal/environmental risk factors for being born small for gestational age (SGA), e.g. Silver-Russell syndrome, congenital heart defects, infections of mothers or smoking during pregnancy, explain the variation in the first-year growth response to GH therapy. METHODS: Secondary analysis was made of growth response in 135 short prepubertal German children (66% males) enrolled in a SGA phase III trial. Initial mean patient age was 6.8 +/- 2.6 years; mean patient height SDS -3.8 +/- 1.2, and GH treatment dose was 0.066 mg/kg body weight per day. RESULTS: Growth velocity increased by 4.5 +/- 2.0 cm/year and height SDS by 1.0 +/- 0.5 SDS. Although patient number was limited and variation was high, both growth response (cm/year) and change in height SDS did not appear to differ between subgroups which also did not differ in terms of Studentized residuals set up in the KIGS growth prediction model for SGA. Likewise, in a step-forward multivariate analysis, the variables Silver-Russell syndrome, congenital heart defects, infections of mothers and smoking were not identified as independent factors influencing growth velocity. CONCLUSION: The retrospectively analyzed genetic and maternal/environmental risk factors for SGA do not appear to explain the observed patient variance in response to GH. Larger prospective studies are needed, however, to substantiate these preliminary findings.

Functional analysis of BMP4 mutations identified in pediatric CAKUT patients.

Human congenital anomalies of the kidney and urinary tract (CAKUT) represent the major causes of chronic renal failure (CRF) in children. This set of disorders comprises renal agenesis, hypoplasia, dysplastic or double kidneys, and/or malformations of the ureter. It has recently been shown that mutations in several genes, among them BMP4, are associated with hereditary renal developmental diseases. In BMP4, we formerly identified three missense mutations (S91C, T116S, N150K) in five pediatric CAKUT patients. These BMP4 mutations were subsequently studied in a cellular expression system, and here we present functional data demonstrating a lower level of messenger RNA (mRNA) abundance in Bmp4 mutants that indicates a possible negative feedback of the mutants on their own mRNA expression and/or stability. Furthermore, we describe the formation of alternative protein complexes induced by the S91C-BMP4 mutation, which results in perinuclear endoplasmic reticulum (ER) accumulation and enhanced lysosomal degradation of Bmp4. This work further supports the role of mutations in BMP4 for abnormalities of human kidney development.

Salt restriction in kidney disease--a missed therapeutic opportunity?

The importance of salt restriction in the treatment of patients with renal disease has remained highly controversial. In the following we marshal the current evidence that salt plays a definite role in the genesis of hypertension and target organ damage, point to practical problems of salt restriction, and report on novel pathomechanisms of how salt affects blood pressure and causes target organ damage.