Use of new peritoneal dialysis solutions in children.

Standard peritoneal dialysis (PD) solutions with low pH and containing high concentrations of lactate and glucose have been demonstrated to negatively affect the peritoneal membrane, mesothelial cell viability, residential peritoneal cells, and also to inhibit phagocytic functions. An increasing body of experimental evidence supports the idea that the peritoneal hypervascularization and fibrosis observed in long-term PD are causally related to the acute and chronic toxicity of conventional PD solutions. A Physioneal (lactate/bicarbonate mixed buffer pH 7-7.4), Physioneal, Extraneal (7.5% icodextrin), Nutrineal (1.1% amino-acid-containing solution) regimen, for example, offers a significant reduction in carbohydrate load (approximately 40-50%), lower exposure to and absorption of glucose degradation products, reduced oxidative stress, and improved volume control when compared with a first-generation DDDD (4 x Dianeal) regimen. The positive aspects of each solution that we have observed in our patients allow a recommendation on the potential benefit of using these solutions in children treated with PD. In fact, data from the literature as well as the results of the studies reported in this paper show that in children the application of neutral pH bicarbonate/lactate-buffered solution for the standard nighttime APD prescription, icodextrin solution for a long daytime dwell, and AA-based solution in malnourished patients is safe and effective. Extended clinical trials should be encouraged to better define the PD schedules for the combined use of these solutions that may be associated with the best clinical efficacy and the highest level of biocompatibility.

Prospective monitoring of polyomavirus BK replication and impact of pre-emptive intervention in pediatric kidney recipients.

Polyoma BK virus (BKV)-associated nephropathy (PVAN) is a relevant cause of poor renal allograft survival. In a prospective analysis, we monitored BKV DNA in blood and urine samples from 62 consecutive pediatric kidney recipients. In patients with BKV replication, we analyzed the impact of reduction of maintenance immunosuppression on viral load kinetics and PVAN in patients with BKV replication. BKV-specific immunity was concomitantly evaluated on blood samples of viremic patients, by measuring the frequency of BKV-specific interferon-gamma-producing and cytotoxic T cells, and BKV IgG antibody levels. At a median follow-up of 24 months, BK viruria was observed in 39 of 62 patients, while BK viremia developed in 13 patients (21%). In all viremic patients, immunosuppression reduction resulted in the clearance of viremia, and prevented development of PVAN, without increasing the rate of acute rejection or causing graft dysfunction. As a consequence of immunosuppression adjustment, an expansion of BKV-specific cellular immunity was observed that coincided with viral clearance. We conclude that treating pediatric kidney transplant patients pre-emptively with immunosuppression reduction guided by BKV DNA in blood is safe and effective to prevent onset of PVAN. BKV-specific cellular immunity may be useful to guide this intervention.

Podocin-related mechanisms in posttransplant [corrected] recurrence of focal segmental glomerulosclerosis [corrected].

Posttransplantation recurrence of focal segmental glomerulosclerosis (FSGS) is one of the most disarming events in human pathology with important social and psychological consequences. It usually occurs in 30% to 50% of patients affected by the primary form of the disease with an abrupt onset in the majority of cases occurring within 1 month of the transplantation. Prediction of recurrent cases and early therapy with plasmapheresis are the main goals of the therapy. Although the mechanism of posttransplantation recurrence is still obscure, it has been proposed to be of a multifactorial origin, in which plasma factors determine the shedding of proteins of the slit-diaphragm, such as nephrin and podocin, with structural alterations of the ultra-filtering unit of the glomerulus. Low resynthesis of podocin and/or haplo-insufficiency due to heterozygous mutations should represent significant predisposing factors to proteinuria. In this review, the role of podocin in posttransplantation recurrence will be evaluated focusing on the possibility that resynthesis of the protein could represent a key step also for stable normalization of the renal filter. The recent characterization of the podocin promoter cis- and trans- acting elements and the possibility to characterize low- and high-podocin producer haplotypes offer opportunities to evaluate the capacity for podocin resynthesis in the donor kidney. A review of the literature on posttransplantation recurrence of FSGS in patients originally carrying homozygous and/or heterozygous NPHS2 mutations supports the general idea of a multifactorial origin of the primary disease that can be extended to the pathogenesis of posttransplantation recurrence.

Successful in vitro priming of EBV-specific CD8+ T cells endowed with strong cytotoxic function from T cells of EBV-seronegative children.

Epstein-Barr virus (EBV)-seronegative transplant recipients are at high risk of developing EBV-associated post-transplant lymphoproliferative disorder (PTLD), and would maximally benefit from an EBV-directed T-cell therapy for prevention or treatment of PTLD. So far, efforts to activate CD8+ EBV-specific cytotoxic T lymphocytes (CTL) endowed with high specific cytotoxicity from EBV-seronegative children have failed. We compared the CD8+ CTL priming efficiency of three different modified activation protocols, based on lymphoblastoid cell lines (LCL) stimulation potentially enhanced by either LCL presentation through dendritic cells, or selection of IFN-gamma+ cultured cells, or culture in the presence of rhIL-12 and rhIL-7, according to the standard protocol for reactivation of EBV-specific CTL. We found that only specific LCL stimulation in the presence of rhIL-12 and rhIL-7 was able to reproducibly expand EBV-specific CD8+ CTL endowed with strong cytotoxic activity from truly EBV-seronegative children. The lines thus activated, which included specificities toward EBV latent and lytic proteins, showed high percentage CD8+ T cells, with <10% naïve CD8+/CCR7+/CD45RA+ cells. Overall, the total number of CD8+ central memory cells, and of CCR7 T-cell effectors was comparable to that observed in healthy EBV-seropositive controls. In conclusion, it is feasible to activate EBV-specific CD8+ CTL with suitable characteristics for in vivo employment from EBV-seronegative children.

Posttransplant recurrence of proteinuria in a case of focal segmental glomerulosclerosis associated with WT1 mutation.

Posttransplant recurrence of inherited focal segmental glomerulosclerosis (FSGS) is still an enigma owing to the evident paradox of the molecular origin of proteinuria. A young girl with FSGS for WT1 mutation (IVS9+4C>T) and Frasier syndrome received a renal transplant at the age of 11 years. After an initial good outcome with recovery of renal function, proteinuria re-appeared after 7 days and steadily increased up to a nephrotic range. Determination of plasma permeability activity showed concomitant high Palb (0.7). At this point, plasmapheresis was started and after nine cycles with 1500 mL exchange and albumin re-infusion, proteinuria decreased to normal range and is still normal after 3 years. This is the first description of posttransplant recurrence of proteinuria in Frasier syndrome that should be included in potential outcome of renal transplant in this category of patients. This observation confirms the concept that recurrence of proteinuria may occur in inherited forms of FSGS so far reported only for patients carrying NPHS2 mutations and reinforces the idea on multifactorial origin of the disease.

Circulating anti-actin and anti-ATP synthase antibodies identify a sub-set of patients with idiopathic nephrotic syndrome.

Idiopathic nephrotic syndrome (iNS) with resistance or dependence to steroids is a common disease in children but in spite of an increasing clinical impact its pathogenesis is unknown. We screened for the presence of circulating antibodies against glomerular (podocytes, mesangium) and tubular cells (tubular epithelia) a cohort of 60 children with iNS including 8 patients with a familial trait of iNS or with proven mutation of NPHS1-NPHS2 and 12 with good sensitivity to steroids. Positive sera were found in 8 cases, all belonging to the category without familial trait/molecular defects. The targets of antibodies were characterized with Western blot and MALDI-Mass utilizing beta-hexyl cell extracts separated with two-dimensional electrophoresis. In all cases antibodies of the IgM class were directed against ATP synthase beta chain alone (4 cases) or in combination with actin (3 cases); one child presented IgG against aldose reductase. The clinical picture was nephrotic syndrome with steroid resistance or dependence and variable cyclosporin sensitivity; 3 patients developed end stage renal failure. The basic pathology picture was focal segmental glomerulosclerosis (FSGS) in 4 cases and mesangial proliferative glomerulonephrites with deposition of IgM in 2. Overall, patients with circulating auto-antibodies could not be readely differentiated on clinical grounds with the exception of 3 children who developed positivity for antinuclear antibodies during the follow-up. Affinity-purified IgM from one patient who underwent plasmapheresis for therapeutical pourposes (but not from a normal pool) induced proteinuria in Sprague-Dawley rats and concomitant human IgM deposition within glomeruli. This is the first report of circulating anti-actin/ATP synthase beta chain antibodies in a subset of patients with iNS. Both pathological significance and clinical impact given by the presence of these antibodies and the relationship with other conditions such as lupus-erythematosus, characterized by their presence, must be defined.

Mycophenolate mofetil pharmacokinetic monitoring in pediatric kidney transplant recipients.

This open-label, longitudinal, long-term study of de novo pediatric renal transplant recipients was designed to investigate the pharmacokinetics (PK) of mycophenolic acid (MPA) and its possible interaction with cyclosporine (CsA). Thirty-four children on an immunosuppressive regimen of CsA, prednisone, and mycophenolate mofetil (MMF, 300-400 mg/m2 twice daily) were investigated at 6, 30, 180, and 360 days after transplantation. Considerable interindividual variability in the areas under the concentration curve (AUC(0-12)) of MPA was observed during the follow-up, although the dose of MMF remained the same over the same time. Predose levels (C0) increased significantly during the first 6 months after transplantation: C0 at 6 and 180 days after transplantation was 0.8 +/- 0.6 and 1.9 +/- 1.1 microg/mL (P < .0001). A significant time-dependent increase in the AUC of MPA was also observed during the first 6 posttransplant months: AUC(0-12) at 6 and 180 days after transplantation was 23.3 +/- 10.8 and 40 +/- 11.6 mg*h/L (P = .003). MPA concentrations 3 and 4 hours after MMF intake were the individual time points that best correlated with the full MPA AUC (r = 0.8 and 0.79; P < .001). The abbreviated MPA AUC (0-4 hours) correlated reasonably with the full AUC (r = 0.87; P < .001). Finally, a significant reduction in CsA dose during the first 6 posttransplant months (P < .001) matched the significant increases in both MPA C0 and full MPA AUC, thus demonstrating the interaction of the 2 immunosuppressive drugs. These observations suggest the need for therapeutic drug monitoring when adjusting the dose of MMF in children.

Lupus nephritis in children.

In systemic lupus erythematosus renal involvement is more frequent in children than in adults. Overall, 60-80% of children with systemic lupus erythematosus have urinary or renal function abnormalities early in the disease course. In 90% of patients, renal disease occurs within two years from disease onset. Clinically significant renal involvement ranges from asymptomatic urinary findings to nephrotic syndrome and renal failure. Long-term prognosis is similar to that observed in adults. Treatment aspects that are peculiar to children include drug side-effects, such as growth inhibition induced by steroids, the need to consider morbidity-related issues with respect to the very long life expectancy of patients and the problems related to the impact of disease in adolescents. The recent availability of a childhood SLE definition of improvement and the presence of large international paediatric rheumatology networks should, in the future, facilitate the implementation of controlled clinical trials devoted to paediatric SLE.

Preliminary report on impact of pretransplant dialysis on early graft function: peritoneal versus hemodialysis.

Delayed graft function and acute renal failure after kidney transplant negatively influence graft outcome. It has been reported that pretransplantation peritoneal dialysis (PD) instead of hemodialysis (HD) correlated with better short-term graft outcome in adult kidney recipients. In this study the impact of PD versus HD was evaluated among pediatric kidney recipients. This study suggested that different forms of dialysis pretransplantation did not affect early graft function among pediatric kidney recipients.

Severe rhabdomyolysis and acute renal failure in a kidney transplant patient treated with tacrolimus and chimaeric CD25 monoclonal antibody.

Recently observations of rhabdomyolysis in patients treated with tacrolimus have been reported. The authors present a kidney transplant patient who had an epileptic seizures, severe rhabdomyolysis, and acute renal failure. The patient was initially immunosuppressed with tacrolimus and chimeric CD25 monoclonal antibody. After intensive therapy with plasmapheresis, CVVH, and dialysis, the patient completely recovered at 11/2 year his serum creatinine is 1.2 mg/dL.

Urinary diversion in infants with primary high-grade vesicoureteric reflux, urinary sepsis and renal function impairment.

INTRODUCTION: General consensus on the optimal treatment of septic infants with primary high-grade vesicoureteric reflux (VUR) and renal function impairment has not been reached. Our study aims at evaluating the role of temporary urinary diversion. MATERIALS AND METHODS: Twenty male infants, affected by sepsis and primary high-grade VUR, underwent urinary diversion in 1996-2001 because of estimated risk of renal function deterioration, due to non-compliance with the antibiotic treatment. Plasmatic creatinine clearance, ultrasonography, micturition cystography and scintigraphy were evaluated. RESULTS: Creatinine clearance was abnormal in 13 infants on admission, in 10 after urinary diversion and in 6 after second surgery. Renal damage (focal or diffuse) was evident in 16 patients, without modifications after surgery. No patient developed urinary tract infections (UTI). Vesicostomy was done in 12 cases, ureterostomy in 8. Nephrectomy was performed in 3 cases with poor renal function, and ureteroneocystostomy in 17. CONCLUSIONS: Urinary diversion in septic infants with high-grade VUR can represent an alternative approach to the conservative or surgical treatment in selected patients presenting risk of renal function impairment. This procedure allowed an easy management of UTI without worsening of renal function while waiting for a better anatomical status to perform reconstructive surgery.

Interfacial effect of extremely low frequency electromagnetic fields (EM-ELF) on the vaporization step of carbon dioxide from aqueous solutions of body simulated fluid (SBF).

Spontaneous processes in an aqueous solution of body simulated fluid (SBF) were monitored in closed vessel for a period of 1 month at 310 K, at atm pressure, and initial pH of 7.2, both with and without exposure to a square pulsed extremely low frequency electromagnetic fields (EM-ELF) of 250 microT, repeated at 75 Hz. The most important findings are that the SBF surface tension (gamma), evaluated under the EM-ELF field, is lower than the corresponding value measured without EM-ELF at any time. Furthermore, the pH of the exposed SBF is always more basic than that of the unexposed solution. As a consequence, when the EM-ELF is applied, calcium phosphate salts do not precipitate from the SBF solution for a period as long as 30 days. Behind all these experimental evidences there is only one mechanism: the vaporisation from the SBF-air interface of the CO(2)(aq) dissolved into the aqueous electrolyte solution. Thermodynamic analysis of these results establish that, at any given time, the difference, Delta, between the measured surface tensions with and without EM-ELF applied, gives the work of the electromagnetic forces to change the extent at which the CO(2)(aq) adsorbs at the liquid-air interface. It has been demonstrated that the work supply per second and per unit of area by the electromagnetic forces, 3.73 x 10(-10) mJ/s cm(2), is very near to the experimental slope in the plot Delta vs. t 1.7 x 10(-10) mJ/s cm(2). This leads to the conclusion that the EM-ELF fields have an interfacial effect on the concentration value of the CO(2) (aq) at the SBF-air interface. Because of that, the EM-ELF field is enhancing the CO(2) vaporisation rate; thus any other steps, which are a consequence of this mechanism, are changing. These results allow explanation of previous experiments concerning the precipitation of calcium carbonate from flowing hydrogen carbonate aqueous solution in the temperature range 353-373 K at a pressure of 0.1 MPa under the effect of static magnetic fields.

Polyomavirus BK infection in pediatric kidney-allograft recipients: a single-center analysis of incidence, risk factors, and novel therapeutic approaches.

BACKGROUND: Although a growing body of literature regarding polyoma BK virus (BKV) infection and associated interstitial nephritis in kidney-allograft recipients is becoming available, the impact of BKV infection in the pediatric population has not been fully evaluated. METHODS: In a retrospective analysis, we performed polymerase chain reaction (PCR) assays for BKV DNA in serum and urine samples from 100 pediatric kidney-allograft recipients referred to our institution in the last 5 years. RESULTS: BKV viruria was observed in 26 of 100 patients, whereas BKV viremia was demonstrated in 5 patients. Serum creatinine was significantly higher in recipients with positive BK viremia compared with BKV DNA-negative patients (mean 2.66 vs. 1.14 mg/100 mL). Renal biopsy performed in 3 of 5 patients showed graft damage consistent with interstitial nephropathy. In the univariate analysis, negative antibody status of the recipient and the presence of mycophenolate mofetil in baseline immunosuppression were the two factors predictive of active BKV infection. CONCLUSIONS: Our study shows that BKV-associated nephropathy is a relevant complication in the pediatric kidney transplantation setting also. Identification of patients at risk of developing virus-associated nephropathy, through prospective quantification of viral load, could improve clinical outcome by allowing the use of timely preemptive therapy guided by BKV DNA levels.

Clinical evaluation of oxidative stress and myocardial reperfusion injury in pediatric cardiac surgery.

BACKGROUND: To evaluate oxidative stress and myocardial damage after aortic crossclamping release (ACCR) during cardio pulmonary bypass (CPB) in children two parameters were investigated: total glutathione (GSH) and its oxidoreductive reactions (GSH/GSSG) as expression of oxidative stress, and plasmatic turnover of myocardial taurine (TAU) as expression of cell damage. METHODS: The study was divided in two periods: 1) first period: analysis of oxidative stress and myocardial damage in 18 children. 2) Second period: evaluation of myocardial cell protection by controlled anterograde low oxygen warm reperfusion (ALOWR) before declamping. Twenty-one children were divided in two groups: not receiving (Group 1, 9 patients) and receiving (Group 2, 12 patients) ALOWR. RESULTS: In the first period GSH values increased significantly after onset of mechanical ventilation (MV) in vein, after CPB start in artery and after ACCR in coronary sinus. Moreover TAU turnover in aortic and coronary sinus blood increased significantly after ACCR. In the second period, Group 2 showed a lower oxidative stress after ACCR, while no differences were observed in TAU turnover. CONCLUSIONS: 1) Assessment of TAU and GSH levels can be considered a good method to clinically evaluate myocardial injury during cardiac surgery. 2) MV and CPB can induce oxidative stress before aortic clamping and can decrease the physiologic scavengers. Therefore, to prevent that depletion, the strategy of these techniques must be adapted to the patient and to his cardiac disease. 3) Intramyocardial TAU turnover is not significantly modified by the reperfusion technique. 4) ALOWR can reduce myocardial oxidative stress and can improve heart recovery after the cardioplegic arrest.

A multicenter survey on automated peritoneal dialysis prescription in children.

Automated peritoneal dialysis (APD) is considered the first-choice chronic peritoneal dialysis modality for pediatric patients. Nighttime APD courses reduce the impact of PD treatment on a patient's and family's way of life, and the wide range of prescription options permit the dialysis schedule to be tailored to the needs of children of varying age and body size. We registered data concerning the dialytic regimens adopted in 12 pediatric dialysis centers for the treatment of 110 children on APD. Of the 110 children, 64 (aged 7.6 +/- 5.1 years) were on nightly intermittent peritoneal dialysis (NIPD); 29 (aged 9.2 +/- 4.3 years) were on tidal peritoneal dialysis (TPD); and 17 (aged 8.2 +/- 4.9 years) were on continuous cycling peritoneal dialysis (CCPD). The main prescription parameters for the various regimens (mean +/- standard deviation) were these: NIPD--exchanges: 13.0 +/- 5.8; duration: 10.0 +/- 1.1 hours; dwell volume: 36.5 +/- 6.2 mL/kg body weight (BW); glucose concentration: 1.69% +/- 0.41%. TPD--exchanges: 23.3 +/- 8.1; duration: 10.0 +/- 1.0 hours; dwell volume: 36.1 +/- 5.9 mL/kg BW; glucose concentration: 1.63% +/- 0.37%. CCPD--exchanges: 13.0 +/- 4.7; duration: 10.1 +/- 1.3 hours; dwell volume: 37.7 +/- 5.2 mL/kg BW; glucose concentration: 1.65% +/- 0.28%. Tidal volume was 52.2% +/- 9.0% of initial fill volume. Daytime dwell volume was 54.8% +/- 17.3% of night volume in CCPD patients, and 56.6% +/- 13.3% in 9 patients on continuous TPD. Because the patient population in this report varied in age, body size, and metabolic needs, the resulting range in prescription parameters was quite wide. Nevertheless, the duration of nightly PD sessions averaged 10 hours, fill volume averaged 36 mL per kilogram body weight, and daytime volume averaged 50% of nighttime fill volume.

Plasma levels of soluble CD30 are increased in children with chronic renal failure and with primary growth deficiency and decrease during treatment with recombination human growth hormone.

BACKGROUND: Previous studies have suggested that in vivo Th2 lymphocyte activation is related to increased soluble CD30 (sCD30) plasma levels. As various hormones (dehydroepiandrosterone, glucocorticoids, progesterone) can regulate the Th1/Th2 balance, and because growth hormone (GH) enhances lymphocyte function, we measured sCD30 plasma levels, before and after treatment with recombinant human GH (rhGH), in children with growth failure due to chronic renal failure (CRF) or to isolated GH deficiency in order to evaluate the potential effects of rhGH treatment on Th1/Th2 balance. METHODS: sCD30 plasma levels were determined by ELISA assay in 30 children with CRF (mean age 10.7+/-3.7 years), in five children with isolated GH deficiency (mean age 11.4+/-2.6 years), and in 10 normal controls (mean age 10.1+/-3.5 years). RESULTS: sCD30 levels were higher in the 30 children with CRF than in the 10 controls (179.8+/-79.4 vs 11.3+/-10.9 U/ml, P<0.001) exhibiting an inverse correlation with glomerular filtration rate (GFR) (r=-0.7860, P<0.001). In 11 children with CRF, after 19.9+/-16.7 months of rhGH treatment, a decrease of sCD30 plasma level (170+/-50 vs 134+/-49 U/ml, P<0.01) was observed. The five children with primary GH deficiency had higher sCD30 plasma level than controls (mean 147+/-105 vs 11+/-10 U/ml, P<0.004) and sCD30 plasma levels decreased to 95.2+/-109.6 U/ml after rhGH treatment. CONCLUSIONS: The finding that rhGH treatment decreased sCD30 plasma levels in children with CRF, and that children with primary GH deficiency had higher sCD30 plasma levels than controls, suggest that GH may regulate CD30 expression and possibly the balance of Th1/Th2. Whether the uraemia-induced increase in sCD30 is due to decreased renal excretion, to overproduction or both, remains to be determined.

Inhibition of renal permeability towards albumin: a new function of apolipoproteins with possible pathogenetic relevance in focal glomerulosclerosis.

Focal segmental glomerulosclerosis (FSGS) is a degenerative renal disease characterized by the accumulation of extracellular matrix and lipids within the glomerular tuft. It has been proposed that an abnormal renal permeabilization towards proteins induced by a putative plasma factor is, in some way, involved in the pathogenesis of the disease. In this paper, we measured the plasma permeability activity (Palb) in several sera of patients with FSGS and found a mean activity of 0.82+/-0.03 which means a marked increase compared to a mean Palb of 0.16+/-0.03 in normal controls. Coincubation of FSGS and normal serum reduced the permeability activity within the normal range; normal serum added to the incubation medium after the glomeruli had already been exposed to the FSGS serum had no effect, suggesting the presence of inhibitory substances with a direct effect on a circulating substrate. Finally, the antipermeability activity was retained when heated to 60 degrees C but not to 100 degrees C. By serial fractionations of normal serum and reported activity measurements at each step, five natural occurring inhibitors of albumin permeabilization were purified and characterized by matrix assisted laser desorption/ionization-mass spectrometry (MALDI-MS), as components of apolipoproteins (apo) (apo E2 and E4, apo L, the high Mr apo J and a 28 kDa fragment of apo A-IV). Coincubation of each apolipoprotein with FSGS serum inhibited permeability, but only apo J and apo E2 and E4 were found to be crucial for the process. In conclusion, we have purified from normal serum five inhibitors of permeability induced by FSGS serum, all corresponding to apolipoproteins. An imbalance between permeability factors and apolipoproteins may play a pathogenetic role in FSGS.