[Childhood ureteropelvic junction obstruction in a regional treatment center: spectrum and therapy]

BACKGROUND

Ureteropelvic junction obstruction is the most frequent malformation of the upper urinary tract and treatment with conservative or operative management remains controversial. In this study we present the retrospective analysis of 129 children with ureteropelvic junction obstruction who underwent conservative or operative management.

MATERIAL AND METHODS

A total of 129 children with ureteropelvic junction obstruction, who were treated in the department of pediatric nephrology at the University of Essen from 1998-2005, were included into the analysis. Clinical charts were reviewed for the parameters urinary tract infections (total number, severity, bacteriology), antibiotics, ultrasound, Tc-99 diuresis renography, and management (conservative or operative). Statistical analysis was performed using the SPSS software (Version 11.0) RESULTS: A total of 89 urinary tract infections was observed in 52 children. The mean width of renal pelvis was 3.04 ± 1.33 cm in the operative group and 1.98 ± 1.2 cm in the conservative group (p=0.001, ANOVA test). Tc-99 diuresis renography was performed in 70 children of which 46 children received primarily conservative management and 24 children were operated. In the conservative group 6 children underwent pyeloplasty later on due to aggravation of renal function. In 59 out of 129 cases diuresis nephrography was not performed due to only mild ectasia.

CONCLUSIONS

This study demonstrates that conservative management is safe in children with ureteropelvic junction obstruction with no or only little constricted renal function, if a close-meshed surveillance protocol is followed and parental compliance is given.

Peripherally circulating CD4⁺ FOXP3⁺ CXCR3⁺ T regulatory cells correlate with renal allograft function

Peripheral immunoregulation depends on T regulatory cell trafficking into the allograft to modulate the local alloresponse. Little is known about the relevance of trafficking receptors for Tregs after solid organ transplantation in humans. In this study, expression of the peripheral chemokine receptors CXCR3 and CCR5 on CD4⁺ FOXP3⁺ Treg cells was analysed and correlated with allograft function in renal transplant recipients. Flow cytometry analysis of peripheral blood mononuclear cells of 54 renal transplant recipients receiving a calcineurin inhibitor-based immunosuppression was performed for CD4, CD25, FOXP3, CXCR3 and CCR5 within the first 18 months post-transplantation. Correlation analysis of chemokine receptor expression and glomerular filtration rate as calculated by MDRD (eGFR) was performed. Expression of the peripheral homing receptors CXCR3 (r = 0.44, P < 0.05) and CCR5 (r = 0.45, P < 0.05) on FOXP3⁺ Tregs correlated with renal allograft function (eGFR) in patients receiving tacrolimus (n = 28), but not cyclosporine A (CsA) (n = 26). CsA but not tacrolimus reduced surface expression of CXCR3 on FOXP3⁺ Tregs in renal transplant recipients as correlated to trough levels (r = -0.42, P < 0.05). In contrast to CD4⁺ CXCR3⁺ CD25(lo) T cells, flow-sorted CD4⁺ CXCR3⁺ CD25(hi) Tregs isolated from healthy individuals did not produce IFNγ or IL-17 ex vivo and expressed high levels of GARP mRNA both at baseline as well as after TCR activation indicating functional regulatory activity. Expression of the peripheral trafficking receptors CXCR3 and CCR5 on FOXP3⁺ Tregs is associated with renal allograft function. These results suggest that Treg trafficking may also depend on the interaction of CXCR3 or CCR5 and their respective ligands.

Cyclosporin but not everolimus inhibits chemokine receptor expression on CD4+ T cell subsets circulating in the peripheral blood of renal transplant recipients

The peripheral chemokine receptors chemokine receptor 3 (CXCR3) and CC chemokine receptor 5 (CCR5) have been reported to be associated with allograft rejection. The impact of the expression of immunosuppressive drugs on peripherally circulating CD4(+) T cell subsets after renal transplantation is unknown. Expression of CXCR3 and CCR5 was investigated by flow cytometry in 20 renal allograft recipients participating in a prospective, randomized trial (NCT00514514). Initial immunosuppression consisted of basiliximab, cyclosporin A (CsA), mycophenolate sodium and corticosteroids. After 3 months, patients were treated either with CsA, mycophenolate sodium (MPA) plus corticosteroids (n = 6), CsA and everolimus plus corticosteroids (n =8) or CsA-free (CsA(free)) receiving everolimus, MPA and corticosteroids (n = 6). After initial reduction of CD4(+) forkhead box protein 3 (FoxP3)(+) and CD4(+) CD25(hi) FoxP3(+) regulatory T cells (T(regs)) (P < 0.05; P < 0.01), 3-month post-transplant percentages of T(regs) were reconstituted in CsA(free) and CsA(lo) arms compared to CsA(reg) 12 months post transplant. Expression of CCR5 and CXCR3 on CD4(+) FoxP3(+) and CD4(+) FoxP3(-) T cells 12 months post transplant was increased in CsA(free) versus CsA(reg). Increase in CCR5(+) CXCR3(+) co-expressing CD4(+) FoxP3(-) cells between 3 and 12 months correlated negatively with the glomerular filtration rate (GFR) slope/year [modification of diet in renal disease (MDRD); r = -0.59, P < 0.01]. CsA, but not everolimus, inhibits both T(reg) development and expression of CXCR3 and CCR5 on CD4(+) T cell subsets. Increase in CCR5(+) CXCR3(+) co-expressing CD4(+) FoxP3(-) T cells is associated with early loss in allograft function.

Functional and total IGFBP3 for the assessment of disorders of the GH/IGF1 axis in children with chronic kidney disease, GH deficiency, or short stature after SGA status at birth

OBJECTIVE

IGFBP3 immunoreactivity may appear elevated in patients with chronic kidney disease (CKD), in part due to accumulation of low molecular fragments. The importance of these IGFBP3 variants for binding and inactivation of IGF1 and their relevance for the impaired growth of uremic children are unclear. Nevertheless, IGFBP3, measured as total (t-)IGFBP3, is frequently used as a diagnostic parameter in pediatric CKD patients. A new assay for functional (f-)IGFBP3 exclusively detects IGFBP3 capable of IGF binding. The aim of the study was to evaluate the significance of f-IGFBP3 measurements for the assessment of uremic abnormalities of the GH/IGF1 axis.

DESIGN

Prospective cross-sectional study.

METHODS

t-IGFBP3, f-IGFBP3, and IGF1 were measured in pediatric CKD patients, including patients with CKD stage 3-4 not on dialysis (CKD, n=33), on dialysis treatment (DT, n=26), patients after renal transplantation (RTx, n=89), healthy children (n=29), children with GH deficiency (GHD, n=42), and small for gestational age (SGA) children (SGA, n=34).

RESULTS

Mean t-IGFBP3 SDS was elevated in CKD, DT, and RTx children compared with controls and GHD patients (P≤0.0004). Highest values were reached in DT (P<0.0001 vs all groups). In contrast, mean f-IGFBP3 was similar in all groups (P=0.30).

CONCLUSIONS

Pediatric CKD patients displayed elevated serum concentrations of t-IGFBP3 but not f-IGFBP3, supporting the hypothesis that IGFBP3 fragments not binding IGF1 accumulate during uremia. f-IGFBP3 is an indicator of IGFBP3 fragmentation and seems to reflect IGF1 binding in CKD better than t-IGFBP3. However, the role of f-IGFBP3 for the diagnosis of disturbances of the GH/IGF hormonal axis appears to be limited.

Primary HHV 6 infection after liver transplantation with acute graft rejection and multi-organ failure: successful treatment with a 2.5-fold dose of cidofovir and reduction of immunosuppression

HHV type 6 has been reported with enhanced pathogenicity in immunocompromised patients. Herein, we report about a two-yr-old girl who experienced primary HHV 6 infection after liver transplantation. She clinically presented with graft rejection and necrotic hepatitis as well as high fever, pneumonitis with respiratory failure and a rash. Therapy with cidofovir of 5 mg/kg per wk did not show improvement, so that a full pharmacokinetic profile of cidofovir was performed. It demonstrated enhanced body weight normalized clearance of cidofovir and cidofovir dosage was augmented to 12 mg/kg per wk to reach adequate drug exposure. With additional reduction of immunosuppression, the patient dramatically improved and liver function stabilized.

Pharmacokinetics, pharmacodynamics, safety, and tolerability of single-dose fingolimod (FTY720) in adolescents with stable renal transplants

Oral fingolimod signals the sphingosine 1-phosphate receptor and this in turn mediates immunomodulatory activity. No data of fingolimod in any pediatric population existed before this study. We put our study results in perspective against data from adult renal transplant patients. We investigated pharmacokinetics and pharmacodynamics of single-dose fingolimod (0.07 mg/kg) and its effects on lymphocytes and heart rate in seven adolescents (14.1 ± 1.6 yr) with stable renal transplants. Blood samples for pharmacokinetics and lymphocytes were collected at screening, baseline, and up to 28 days post-dosing. Cardiac monitoring included 12-lead ECG, 24-h Holter monitoring, and echocardiography. A fingolimod dose of 0.07 mg/kg resulted in mean AUC of 731 ± 240 ng·h/mL and C(max) of 3.6 ± 0.6 ng/mL. Drug exposure was nearly identical to adults receiving the same dose. Absolute lymphocyte count decreased 85% from baseline; average nadir occurred by six h post-dose. Heart rate decreased from 74 bpm (predose mean) to 53 bpm (nadir) three h post-dose. Mean heart rates recovered by Day 14 (75 bpm). Weight-adjusted doses of fingolimod in adolescents resulted in drug exposure similar to adults. Adolescents and adults shared comparable negative chronotropic effects and decreased lymphocyte count. Recovery trajectories of these parameters back to baseline were similar between age groups.

Cyclosporin in idiopathic glomerular disease associated with the nephrotic syndrome : workshop recommendations

Management of idiopathic glomerular disease associated with nephrotic syndrome (INS) remains controversial and one of the most complex areas relates to utilization of the drug cyclosporin. This is despite its demonstrated effectiveness in several histologic types of the INS in randomized controlled trials. Cyclosporin is effective in inducing remission of proteinuria in approximately 80% of steroid-sensitive cases of minimal change disease (MCD). Cyclosporin is also effective in both the induction of remission and long-term preservation of renal function in steroid-dependent/-resistant MCD and steroid-resistant focal segmental glomerulosclerosis (FSGS). The overall response rate in FSGS is lower than in MCD, and long-term therapy (>12 months) may be required to both achieve remission and sustain it. Cyclosporin therapy is also of benefit in reducing proteinuria in 70-80% of patients with steroid-resistant membranous nephropathy (MGN). In MGN, the maximum benefit is often delayed compared to MCD (>12 weeks). Cyclosporin is generally well tolerated and safe. The major concern remains the nephrotoxicity, but with careful monitoring of the patient's renal function; minimizing the maintenance dose and utilizing repeat renal biopsy in those receiving long-term therapy, this risk can be minimized. The algorithms have been developed derived from the best evidence in the literature in each of the histologic types to help provide a guide to the integration of cyclosporin into the management of INS for the practicing nephrologist.

Immigrating progenitor cells contribute to human podocyte turnover

Podocyte depletion is a critical event in glomerular diseases in general and in the development of focal segmental glomerulosclerosis in particular. Progenitor cell immigration is a possible mechanism of podocyte replacement for the preservation of nephron function since, with rare exception, mature podocytes are thought to be incapable of replication. We examined eight paraffin-embedded renal biopsies from six male recipients of female transplant kidneys for receiver-derived podocytes. Fluorescent in situ hybridization for the Y chromosome was combined with immunofluorescence for the podocyte marker, Wilms tumor-1 antigen. Recipient-derived podocytes were found in 4 of 8 biopsies representing 3 of the 6 patients. Overall, 5 of the 740 podocytes examined in the female-donated kidneys were male derived. Our study suggests that immigrating progenitor cells are able to replace podocytes in humans; however, the importance of this process in physiologic and pathologic conditions is unknown.

Clearance and removal of oxalate in children on intensified dialysis for primary hyperoxaluria type 1

Patients with end-stage renal failure owing to primary hyperoxaluria type 1 (PH1) receive dialysis while waiting for transplantation. So far, dialysis has not been shown to overcome the problem of ongoing oxalate production and deposition at extrarenal sites. We report on six children with PH1 who had to be dialyzed for a median period of 2.5 years while awaiting liver transplantation. Aiming at preventing oxalate tissue accretion, oxalate mass transfer was studied and dialysis intensified accordingly. Mean plasma oxalate concentration was between 51 and 137 micromol/l. In three of the six patients with a urinary output between 630 and 3140 ml, urinary removal of oxalate was between 5.6 and 12.4 mmol/week/1.73 m2. Hemodialysis (HD) in five of the six patients demonstrated a mean oxalate dialysance between 158 and 444 l/week/1.73 m2. Peritoneal dialysis (PD) in two of the six patients showed mean oxalate clearances of 66 and 103 l/week/1.73 m2. One patient received HD and PD. By adding all modes of elimination, a mean total oxalate mass between 10.1 and 24.1 mmol/week/1.73 m2 was removed. Dialysis is still necessary as a temporary therapy for a number of patients with PH1. Dialysis should be instituted pre-emptively and maximally exploited by intensified HD/PD treatment protocols, without, however, cutting back urinary output.

[Obstructive nephropathy]

Congenital anomalies of the kidney and urinary tract (CAKUT) are regarded as a single entity. The degree of obstruction may have an additional influence on the parenchymal malfunction. Congenital dilatation of the upper urinary tract associated with symptomatic urinary tract infection must be treated early with intensive antibiotic therapy. In some cases temporary urinary diversion is also required. Further diagnostic procedures are then postponed in such cases. In all other cases of dilatation of the upper urinary tract diagnosed prenatally or early in the postnatal period, diuresis renography is still the cornerstone of diagnosis, even though it has definite limitations in young infants and in babies with poor kidney function. Functional gadolinum MR-urography will become the method of choice in the near future, since it combines good functional and excellent morphological presentation. When an obstruction hampering function is definitely present surgical correction is indicated: open and endoscopic surgery yield similarly good results. Molecular markers in CAKUT may soon be used as prognostic indicators. Examination of the molecular alterations that occur in renal and urinary tract anomalies may also lead to medicamentous protection of renal function.

Unusual Manifestation of Posttransplant Lymphoproliferative Disorder in the Esophagus

Early manifestations of posttransplant lymphoproliferative disorders (PTLD) are mainly associated with a primary Epstein-Barr virus (EBV) infection. Rapid increases in peripheral blood EBV DNA load are supposed to reliably predict PTLD. We report a boy who 6 months after living-related kidney transplantation presented with an extranodal esophageal manifestation of PTLD. Despite a primary EBV infection with tonsillitis, the peripheral blood EBV DNA remained low, hiding the progression to PTLD.

Medical and surgical aspects of pediatric renal transplantation using living donors

The outcomes of 19 consecutive living-donor renal transplants (LD-RTx) was compared with 41 cadaveric grafts (CD-RTx) performed at our institution using basiliximab, cyclosporine, and prednisone as standard immunosuppression. LD-RTx significantly shortened the waiting time on dialysis. However, patient survival (100% in both groups), 1-year graft survival (94.7% vs 90%), and rejection-free graft survival (76.9% vs 73.5%) was not significantly different. LD-RTx showed better glomerular filtration rates in the early phase after transplantation, a difference that faded with time. Graft function was similar after 1 and 2 years. LD grafts with double renal arteries were used successfully in four cases; heparin therapy was administered to avoid graft thrombosis. A significantly greater number of lymphoceles was observed with LD grafts (7/19 vs 1/41, P < .01). In conclusion with improved immunosuppression producing better results with CD grafts, the advantages of LD-RTx have vanished. LD grafts with double arteries may be used successfully and LD-RTx allows a shorter dialysis period. The high incidence of lymphoceles in our series awaits further evaluation.

The impact of cyclosporine on the development of immunosuppressive therapy—pediatric transplantation using cyclosporine

Cyclosporine A (CsA) was introduced to pediatric renal transplantation more than 20 years ago, and it has greatly improved graft survival and made transplantation the treatment of choice for children with end-stage renal failure. Exposure to CsA was shown to be highly variable among transplant recipients. Therefore, major efforts have been employed to monitor CsA blood levels. The widely used trough levels had never been formally validated, and every center had defined its own target values. With the advanced microemulsion formula of CsA, drug exposure became more predictable, but scientifically evaluated monitoring concepts are still lacking. Monitoring the absorption phase using single time points (eg, 2 hours after ingestion) is promising, as shown in adult trials. In pediatric transplant recipients, randomized clinical trials have to be implemented urgently to fully exploit the potential of CsA in the prevention of graft rejection while minimizing toxicity. Although newer immunosuppressive drugs have been developed, further studies should be undertaken to define the role of CsA in combination protocols.

[Occurrence, diagnostics and therapeutic management of hydronephrosis in pediatric patients in Germany]

As urinary tract obstruction in children may impair renal function, the early detection and evaluation of the degree of obstruction using adequate diagnostic tools is necessary for the choice of the optimal therapeutic procedure. This study describes diagnostic and therapeutic standards in relation to the quality of management of pediatric hydronephrosis in Germany in the first 6 months of the year 2000. In our study 407 of 711 (57.2%) children with a hydronephrotic condition were detected by routine ultrasound. This, and the fact that 25% of the patients, who were prenatally detected, had a diagnosis of vesicoureteral reflux, underlines the importance of this routine procedure. Our study illustrates the panel of diagnostic and therapeutic procedures used in the management of pediatric hydronephrosis in Germany.

Single-dose pharmacokinetics and tolerability of everolimus in stable pediatric renal transplant patients

Everolimus (Certican; RAD), a novel macrolide with potent immunosuppressive and anti-proliferative activities, prevents acute rejection in adult recipients of renal transplantation. This phase I trial conducted in stable pediatric renal transplant patients examined the single-dose pharmacokinetics, safety, and tolerability of everolimus in combination with cyclosporin A (CsA; Neoral) and corticosteroids, with or without azathioprine. Nineteen pediatric patients were enrolled and received a single 1.2 mg/m2 dose of everolimus. Everolimus was safe and well tolerated, with a low incidence of adverse events reported and none judged to be related to the study medication. Everolimus administration did not increase infection rates or produce clinically significant changes in vital signs or changes in electrocardiograms. Apparent clearance and volume of distribution of everolimus increased with age, weight, and body surface area in a generally linear manner across the pediatric demographic ranges. Compared with adults from a previous study, apparent clearance (L/h) and distribution volume (L) were lower in pediatric patients, whereas the elimination half-life was similar. Single-dose everolimus co-administration did not affect the steady-state pharmacokinetics of CsA. Based on this information, pediatric patients will need a dose scaled down for body size, but can probably maintain the same twice-daily dosing schedule used in adults.

Measurement of blood pressure at home: survey among pediatric nephrologists

Recently, an international consensus paper was published for standardization of home self-blood pressure (BP) measurement in adults. However, few data exist regarding home BP measurement in children, although it is recommended for all pediatric patients on renal replacement therapy in Germany. Therefore, a survey was performed among German-speaking pediatric nephrologists (members of the Arbeitsgemeinschaft Pädiatrische Nephrologie) in order to study their opinions about home blood pressure measurements. Approximately 75% of German pediatric nephrology centers responded to the survey. More than 70% of the interviewees prescribed a blood pressure device for all children with renal diseases and hypertension or on renal replacement therapy. For children with antihypertensive medication, 2.8 daily measurements were recommended at mean and 2.2 measurements for children without therapy. Auscultation of Korotkoff sounds and oscillometric BP measurements were used in the same percentage for home BP recordings. The upper cut of level for home blood pressure values was rated by the pediatric nephrologists and compared to reference values of casual blood pressure. There was good agreement for upper systolic BP, but as many as 40 to 50% of the interviewees accepted upper diastolic BP values higher than the 97th percentile for casual BP. Home BP measurement was judged to be more important than office BP measurement by 64% of the nephrologists and less important than 24 h ambulatory blood pressure monitoring by 67%. The results of the survey showed wide discrepancies for standards of home BP measurement in children and adolescents, especially for the recommendations for upper diastolic BP. Before home blood pressure measurements can be recommended unrestrictedly in children and adolescents, we stress the need for standardization of blood pressure devices and measurement. Prospective studies in children are needed to demonstrate that these standards facilitate better prediction of cardiovascular outcome using home BP measurements compared to office BP recordings in children.

Incidence, impact on survival, and risk factors for multi-organ system failure in children following liver transplantation

Liver transplantation (LTx) in children currently offers long-term survival rates of more than 80%. Many causes for Tx failure have been identified. However, the incidence and impact of multi-organ system failure (MOSF) are, to date, unknown. Therefore, in this study the role of MOSF after LTx in children was investigated with regard to outcome. The data of 114 children (53 girls, 61 boys; median age 4.3 yr) after first LTx were evaluated retrospectively. The definition of MOSF, as used by Wilkinson et al. [Crit Care Med 1986: 14: 271-274], was modified with regard to age-adjusted values. The influence of MOSF on patient survival was investigated by Kaplan-Meier analysis and multivariate regression analysis. Thirty-one of 114 children with orthotopic LTx developed MOSF (involving two or more organs). In total, 18 children died (15.8%) during the hospitalization; 16 of these had MOSF. Mortality related to two-organ failure was 29.4% (n = 5), to three-organ failure 78% (n = 7), and to four-organ failure 80% (n = 4). The highest mortality rates were observed in children with central nervous system (CNS) and cardiovascular failure, leading to a decreased probability of survival of 0.40 (p < 0.0001). Multi-variate analysis showed that CNS and cardiovascular failure were the most important risk factors for survival (p < 0.0001 and 0.056, respectively). Respiratory and renal failure, in univariate analysis, were significant contributors to poor survival, but had no statistically significant influence on outcome in multivariate analysis. Bone marrow insufficiency was found to have no influence on survival in either analysis. In multivariate analysis, the risk of development of MOSF was significantly increased by high numbers of transfused units of fresh-frozen plasma (FFP), the absence of rejection episodes, or a high bilirubin level prior to Tx. Hence, MOSF is a major factor contributing to the death of children early after LTx. CNS and cardiovascular failure carried the highest risk for a poor outcome. Other risk factors associated with the development of MOSF were: numbers of transfused units of FFP, absence of rejection episodes, and a high pre-Tx bilirubin level.

Efficacy and tolerability of interleukin-2 receptor blockade with basiliximab in pediatric renal transplant recipients

Rejection remains a major threat in pediatric renal transplantation (Tx), causing graft failure and increased exposure to drugs. The new chimeric antibody, basiliximab, directed against the alpha-chain of the interleukin-2 receptor (IL-2R), has been shown to be effective in preventing rejection episodes in adult renal transplant recipients. In our single-center experience from Essen, Germany, we evaluated prospectively the efficacy and tolerability of basiliximab, in combination with cyclosporin A (CsA) and prednisone, in 38 unselected pediatric patients. Mean patient age at Tx was 10.1 yr. Twenty-eight children received a cadaveric organ and 10 children received living-related donor grafts. The 1-yr patient survival rate was 100% and the 1-yr graft survival rate was 95% (36/38 patients). No graft was lost as a result of immunological factors, and single rejection episodes were observed in eight patients (21%). Two of these rejections were steroid-resistant and responded to tacrolimus rescue therapy. The rate of infections was not enhanced; overt cytomegalovirus (CMV) disease was observed in two patients only. Malignancies have not been seen to date. The blockade of the alpha-chain of the IL-2R lasted for up to 6 weeks. We conclude that the addition of basiliximab to standard immunosuppression in pediatric renal transplant recipients is well tolerated and results in a low incidence of rejection. The simple mode of application and the lack of side-effects make basiliximab an especially useful adjunct in pediatric patients.

Development of liver size and perfusion after reduced-size liver transplantation in children

The technique of segmental liver transplantation (s-LTx) provides a method to overcome the shortage of suitable livers for small recipients. Patient survival rates are parallel to those obtained with whole liver transplantation (w-LTx). For long-term rehabilitation, adaptive liver growth and adequate perfusion is crucial; however, morphometric and hemodynamic parameters in growing children with s-LTx are not available. Seventeen children who received a s-LTx and 25 with a w-LTx who had follow-up evaluation 1 and 2 yr after LTx were studied. Mean age at time of transplantation was 4.3 +/- 3.5 yr for s-LTx and 10.3 +/- 6.0 yr for w-LTx, mean height 98 +/- 21 cm and 122 +/- 30 cm respectively. At follow-up evaluation mean values for liver enzymes, bilirubin and prothrombin time were in the normal ranges for both groups. Liver dimensions were measured by gray scale ultrasound, and hemodynamic parameters by Doppler sonography in the portal vein and hepatic artery using an Acuson 128 machine. Maximal (Vmax), minimal (Vmin) and time-average velocity (TAV) were measured and the resistive index (RI) calculated. We found that 1 and 2 yr after LTx liver dimensions were at a mean in the upper normal range of healthy controls. Spleen size was above the normal range and did not show any tendency towards regression. Mean Vmax in the hepatic artery in s-LTx and w-LTx was 48 cm/sec vs. 28 cm/sec after 1 yr and 30 cm/sec vs. 35 cm/sec after 2 yr, the RI 0.66 vs. 0.55 and 0.59 vs. 0.73, respectively (p for all parameters > 0.05). Maximal portal vein flow was 25 cm/sec in s-LTx vs. 29 cm/sec in w-LTx. Blood flow calculated by vessel diameter and TAV showed no statistical difference between both groups. In conclusion, liver size after s-LTx and w-LTx was increased to the upper normal range, and portal vein blood flow velocities were within the normal range. Vmax in the hepatic artery was reduced in s-LTx; however, the reduction was to the same extent as in w-LTx. In the view of long-term functional adaptation, s-LTx is not inferior to w-LTx.

In-vivo studies do not support a major functional role for the Gly389Arg beta 1-adrenoceptor polymorphism in humans

beta 1-adrenoceptors play a pivotal role in regulating contractility and heart rate in the human heart. Recently, a polymorphism of the beta 1-adrenoceptor has been detected: at amino acid position 389 either Gly or Arg has been found with the Gly389 exhibiting reduced responsiveness upon agonist-induced stimulation in vitro. In order to find out whether the Gly389 polymorphism exhibits blunted responsiveness also in vivo we studied, in healthy volunteers, the effects of exercise on heart rate and heart rate-corrected duration of electromechanical systole (QS2c as a measure of inotropism) which, in humans, is mediated by beta 1-adrenoceptors stimulation. Twenty-four healthy volunteers (12 female, 12 male) homozygous for the Gly389 or Arg389 exercised on a bicycle in supine position (25, 50, 75 and 100 W for 5 min each), and heart rate and QS2c were assessed; in addition, plasma renin activity (PRA) was determined which is also regulated by beta 1-adrenoceptors in humans. Exercise caused work-load dependent increases in heart rate and PRA, and shortening of QS2c; however, these changes were not significantly different between the Gly389 and Arg389 polymorphism. Thus, these three beta 1-adrenoceptor responses did not differ between volunteers with the Arg389 versus the Gly389 polymorphism. Intragroup analysis, however, revealed that exercise induced increase in heart rate and shortening of QS2c were higher in female than in male volunteers. In conclusion, our data do not support the idea that the reduced responsiveness of Gly389 against agonist-induced stimulation observed in vitro is of major functional importance in vivo.

Platelet adenylyl cyclase signaling remains unaltered in children undergoing hemodialysis treatment

Patients with chronic renal failure exhibit multiple endocrine, gastrointestinal and cardiovascular abnormalities, many of which may be explained by alterations of adenylyl cyclase (AC) responsiveness and/or G-protein expression. Since such alterations were previously reported, e.g., for platelets of adult chronic renal failure patients undergoing hemodialysis treatment (HD), we have investigated whether children with chronic renal failure undergoing HD exhibit similar alterations. Eleven uremic children undergoing HD were compared with 11 age-matched healthy controls. Platelet AC activity was determined in the absence (basal) and presence of a receptor agonist, direct G-protein activators and direct AC stimulators. G-protein alpha-subunits were measured by quantitative immunoblotting. Basal and stimulated platelet AC and immunoreactivity for platelet G-protein alpha-subunits did not significantly differ between HD and control children. We conclude that HD in children is associated with much smaller, if any, abnormalities of blood cell signal transduction than in adult patients. We speculate that quality of dialysis, age, and underlying disease might differentially influence blood cell signal transduction cascades.

Progressive familial intrahepatic cholestasis: partial biliary diversion normalizes serum lipids and improves growth in noncirrhotic patients

OBJECTIVES

Progressive familial intrahepatic cholestasis (PFIC) usually presents with pruritus, jaundice, hepatomegaly, and growth failure. A group of PFIC is recognized by marked elevation of total serum bile acids, decreased serum apolipoprotein A-1, and high-density lipoprotein, but normal gamma-glutamyltranspeptidase and cholesterol. Although medical therapy generally fails, partial external biliary diversion (DIV) has been used with promising results for cholestasis. However, little has been reported of its effect on linear growth, synthetic liver function, and lipid metabolism.

METHODS

DIV was performed on six noncirrhotic children with PFIC, all suffering from severe pruritus and cholestasis, refractory to medical treatment. Stature was below -1 (median, -2.3) standard deviation score (SDS) for height in all cases. All patients had markedly enhanced bile acids (307 +/- 72 microl/L), markedly decreased high-density lipoprotein (20 +/- 7 mg/dl), and apolipoprotein A-1 (58 +/- 37 mg/dl), but normal gamma-glutamyltranspeptidase and cholesterol. In addition, cholinesterase activity, monoethylglycinexylidide test, and Fischer's ratio indicated a significantly reduced synthetic liver function in all children but the youngest.

RESULTS

After DIV, all patients were consistently relieved of pruritus, and experienced normalization of all liver function tests, including cholinesterase activity, monoethylglycinexylidide test, and Fischer's ratio, as well as the serum lipid profile within 1 yr. In addition, a marked catch-up growth (median, +/- 1.3 SDS) was evident after 1 yr in all cases.

CONCLUSIONS

This report shows an excellent result of DIV in noncirrhotic PFIC patients and compares favorably with other reports. All patients experienced complete remission, including normalization of synthetic liver function and lipid metabolism. For the first time we have shown that DIV can also be associated with an accelerated growth in these patients.

Neonatal renal venous thrombosis in Germany between 1992 and 1994: epidemiology, treatment and outcome

Renal venous thrombosis (RVT) occurs mainly in the neonatal period and bears a dismal prognosis for individual kidney function. There is no generally accepted therapeutic regimen as controlled clinical trials are lacking. Over the last few years, thrombolytic therapy has been successfully employed by single centres. The present study set out to gather up-to-date information on the incidence, therapy and outcome of neonatal RVT as part of a prospective nation wide survey on neonatal thrombosis in Germany to serve as a basis for therapeutic trials in the future. Between 1992 and 1994 the minimum incidence of symptomatic neonatal RVT in Germany was 2.2 per 100,000 live births (95% confidence interval 1.4-3.3). Out of 35 cases, RVT occurred in 15 premature babies (incidence 13 per 100,000 live births (95% confidence interval 5.9-24.8). Ten babies had associated caval occlusion. Therapy was supportive in 8, low dose heparin was used in 14, full heparinization in 9 and thrombolytic therapy in 4 children. On follow-up after a median time of 11.5 months, renal atrophy was present in 26 out of 39 affected kidneys.

CONCLUSION

Neonatal renal venous thrombosis still leads to irreversible kidney damage in the majority of cases. Because of the low incidence a multi-national multi-centre therapeutic trial over a long period has to be considered in order to determine the optimal therapeutic approach.

Color Doppler energy--a new technique to study tissue perfusion in renal transplants

Information on renal tissue perfusion after transplantation remains important for renal allograft monitoring. Findings obtained by conventional Doppler sonography are limited to vascular resistance (RI). The new technique color Doppler energy (CDE) is Doppler angle independent, omits flow velocity and direction, and is proportional to the returning signal strength. The aim of our study was to standardize the application of this technique and to analyze the information obtained. Forty-six CDE studies were performed with an Acuson 128XP in 28 children (mean age 12.4+/-5.3 years) between 4 days and 10 years after renal transplantation. The most-reproducible information was obtained with a 5-MHz linear probe and a constant area of 2x3 cm (log compression 40 dB, filter 3). CDE provided a high-resolution cross-sectional display of perfused cortical tissue vessels. According to the density of signals, the perfusion could be grouped into six perfusion scores (PS). The interobserver concordance was more than 85%. No correlation was found between PS and RI or blood pressure. However, there was a significant correlation between PS and glomerular filtration rate (r=-0.78, P<0. 001). These first results demonstrate a significant relationship between PS and chronic rejection. Non-rejection-related functional impairment exhibited no decrease in PS. We conclude that our proposed standardized CDE renal study is observer independent. CDE is a promising new technique that provides information on renal allograft dysfunction that is different from classical color Doppler findings. Further studies will clarify its role in renal transplant monitoring and its ability to replace more-invasive techniques.

Kidney transplanted children come of age

BACKGROUND

The aim of renal replacement therapy in children is to restore their potential for normal growth and development in order to reach mature adulthood. Because pediatric kidney transplantation started in the late 1960s, it is now possible to document the progress and outcome of these patients from transplantation in childhood to survival into adulthood.

METHODS

In this single-center study, all 150 children born before December 1977 and having received a kidney transplant between 1970 and 1993 were selected for long-term follow-up. The mean age at transplantation was 12.1 years (range 3.2 to 16.7), and the mean follow-up was 13.1 years (range 2.0 to 25.0). In December 1995, 124 grown-up patients with a mean age of 25.4 years (range 18.4 to 40.3) were alive, 89 with a functioning graft. Fifty had the first graft functioning longer than 10 years. The fate of all patients was traced, and those living were analyzed in regard to their somatic and socioeconomic states.

RESULTS

The actuarial 25-year survival rate for the patients was 81%, and for the first graft it was 31%. The best graft survival rates were observed after living related donation, preemptive transplantation, and immunosuppression with cyclosporine. The latter benefit, however, vanished after eight years. The mean creatinine clearance declined over the years from 76 to 45 ml/min/1.73 m2, and the incidence of hypertension increased to more than 80% of the patients. Malignancies occurred in 2.6%. Final height was stunted in 44% of noncystinotic patients, whereas all patients with cystinosis were extremely growth retarded. Twenty-seven percent suffered from additional disabilities. A majority of adult patients were rehabilitated in regard to education and socioeconomic status, and 14% were unemployed.

CONCLUSIONS

The results indicate that renal transplantation in children leads to a high degree of rehabilitation in adulthood. The life of a kidney transplant, however, is limited, which points out the need for more specific immunosuppression with fewer side-effects in order to reach the goal of lifelong graft function.

Prediction of survival in extrahepatic biliary atresia by hepatic duplex sonography

BACKGROUND

The clinical course of biliary atresia patients is extremely variable. To optimize conservative treatment and correctly schedule liver transplantation, noninvasive investigations that are predictive of individual survival and that can be performed regularly are needed. In this study, the prognostic value of Doppler sonography was investigated in these patients.

METHODS

Thirty biliary atresia patients (age range, 1 month to 15.2 years; mean, 4.0 years) and 38 control subjects underwent standardized Doppler sonography of liver and spleen. Biochemical tests of liver function and of fibrogenesis were performed in parallel. Individual clinical outcome was registered 1 and 2 years later.

RESULTS

In control subjects, maximum portal flow velocity (Vmax) was more than 16 cm/sec, and the hepatic vein flow pattern was triphasic. Among children with biliary atresia, those with diminished portal Vmax, a flattened hepatic vein flow curve, or a hepatic artery resistance index of 0.8 or more had significantly lower indices of hepatic protein synthesis (albumin, cholinesterase), higher bilirubin levels, and higher concentrations of markers of connective tissue turnover (procollagen peptides, laminin P1) than did those with normal Doppler sonography measurements. The rate of survival without transplantation during the following 2 years was significantly lower in children with abnormal Doppler findings. From portal and hepatic vein flow measurements, patient survival 2 years later could be predicted with an accuracy of 93%.

CONCLUSIONS

In children with extrahepatic biliary atresia, Doppler sonography of the hepatic blood flow is a noninvasive indicator of disease severity. Moreover, it allows a highly accurate prediction of patient survival for the following 2 years.

End-stage renal failure in children younger than 6 years: renal transplantation is the therapy of choice

Between 1975 and 1994, 46 children under 6 years of age received a total of 52 renal transplants. Obstructive uropathy and dysplasia accounted for most causes of terminal renal failure (17 and 12 cases respectively). Four patients required a second, 1 patient a third transplantation. Cadaveric organs were used on 33 occasions; 19 patients received a living-related donor kidney. Immunosuppression was performed with azathioprine in 5, with cyclosporine A in 21 and combined azathioprine/cyclosporine therapy in 20 cases. After 1 year, graft survival was 81%, and after 5 years 78%. Creatinine clearance declined slightly between 1 and 5 years from 69 to 56 ml/min per 1.73 m2. Main causes of graft failure were thrombotic complications in 6 cases and death with functioning graft in 5 cases. Graft thrombosis occurred only in grafts from young donors under the age of 7 years and after vascular anastomosis to the iliac vessels. Only two transplants were lost in rejection episodes. Patient survival was 94% after 1 and 90% after 5 years. Two patients died due to septiacemia, 1 died of a ruptured aortic aneurysm, 1 of cerebral ischaemia and 1 suddenly of unknown cause. Patient and graft survival was not different compared with 204 patients aged 6-16 years who received a renal transplantation during the same time period at our institution. After transplantation the patients receiving cyclosporine A showed a marked catch-up growth in the 1st year. The median standard deviation score (SDS) of body length improved from -2.63 to -1.39 standard deviations.

CONCLUSION

Renal transplantation is the treatment of choice in end-stage renal failure in children under 6 years.