Acquired Renal Cystic Disease After Liver Transplantation in Children

Glomerular filtration rate in liver transplant for unresectable hepatoblastoma

Most children with hepatoblastoma manifest, at the time of LT, a decrease in renal function due to chemotherapy that could be further deteriorated by the use of calcineurin inhibitors. The purpose of this work was to examine the long-term follow-up of renal function in a cohort of children transplanted for unresectable hepatoblastoma. We present a retrospective observational study of 10 pediatric patients who received a LT for unresectable hepatoblastoma between 1996 and 2016. All patients included in this study were followed up on a regular basis and were assessed for GFR before transplantation and at least once a year during follow-up. All patients received standardized chemotherapy treatment for hepatoblastoma and immunosuppression according to hospital protocols. There was a marked decrease in GFR at the time of the LT in five patients presenting renal complications during the pretransplant cycles of chemotherapy. Three patients, one of them with prior kidney involvement, presented complications after LT, namely acute kidney failure and decrease in GFR. Those patients who presented with the lowest GFR at the time of LT eventually recovered renal function at levels similar to the rest of the group on follow-up. Chemotherapy-induced nephrotoxicity is a concern in patients treated for hepatoblastoma. Some individuals will develop low GFR after chemotherapy; therefore, strict follow-up is recommended, as low GFR may affect the doses of subsequent chemotherapy and immunosuppression. Stabilization of GFR levels and occasional improvement can be observed in the post-transplant period.

[Kidney Cysts and Cystic Nephropathies in Children - A Consensus Guideline by 10 German Medical Societies]

This consensus-based guideline was developed by all relevant German pediatric medical societies. Ultrasound is the standard imaging modality for pre- and postnatal kidney cysts and should also exclude extrarenal manifestations in the abdomen and internal genital organs. MRI has selected indications. Suspicion of a cystic kidney disease should prompt consultation of a pediatric nephrologist. Prenatal management must be tailored to very different degrees of disease severity. After renal oligohydramnios, we recommend delivery in a perinatal center. Neonates should not be denied renal replacement therapy solely because of their age. Children with unilateral multicystic dysplastic kidney do not require routine further imaging or nephrectomy, but long-term nephrology follow-up (as do children with uni- or bilateral kidney hypo-/dysplasia with cysts). ARPKD (autosomal recessive polycystic kidney disease), nephronophthisis, Bardet-Biedl syndrome and HNF1B mutations cause relevant extrarenal disease and genetic testing is advisable. Children with tuberous sclerosis complex, tumor predisposition (e. g. von Hippel Lindau syndrome) or high risk of acquired kidney cysts should have regular ultrasounds. Even asymptomatic children of parents with ADPKD (autosomal dominant PKD) should be monitored for hypertension and proteinuria. Presymptomatic diagnostic ultrasound or genetic examination for ADPKD in minors should only be done after thorough counselling. Simple cysts are very rare in children and ADPKD in a parent should be excluded. Complex renal cysts require further investigation.

Juvenile erythrocytosis in children after liver transplantation: prevalence, risk factors and outcome

Most reports of post-transplant erythrocytosis have involved kidney recipients and, so far, there have been no large studies of onset of erythrocytosis after orthotopic liver transplantation (OLT) in children. We present a long-term survey of pediatric liver recipients, evaluating prevalence, outcome and the main potential causes of erythrocytosis, including a comprehensive mutational analysis of commonly related genes (mutations of HBB and HBA, JAK2, EPOR, VHL, EPAS1 and EGLN1). Between 2000 and 2015, 90 pediatric OLT recipients were observed for a median period of 8.7 years (range 1–20.4 [IQR 4.9–13.6] years). Five percent of the study population (4 males and 1 female) developed erythrocytosis at 8.5 years post OLT (range 4.1–14.9 [IQR 4.7–14.7]) at a median age of 16.6 years (range 8.2–18.8 [IQR 11.7–17.7]). Erythrocytosis-free survival after OLT was 98.6% at 5 years, 95% at 10 years, and 85% at 15 years, with an incidence rate of 6/1000 person-years. No cardiovascular events or thrombosis were reported. No germinal mutation could be clearly related to the development of erythrocytosis. One patient, with high erythropoietin levels and acquired multiple bilateral renal cysts, developed clinical hyper-viscosity symptoms, and was treated with serial phlebotomies. In conclusion, this prospective longitudinal study showed that erythrocytosis is a rare complication occurring several years after OLT, typically during adolescence. Erythrocytosis was non-progressive and manageable. Its pathogenesis is still not completely understood, although male gender, pubertal age, and renal cysts probably play a role.

Approach to the Child with Hematuria

The causes of macroscopic and microscopic hematuria overlap; both are often caused by urinary tract infections or urethral/bladder irritation. Coexistent hypertension and proteinuria should prompt investigation for glomerular disease. The most common glomerulonephritis in children is postinfectious glomerulonephritis. In most patients, and especially with isolated microscopic hematuria, the diagnostic workup reveals no clear underlying cause. In those cases whereby a diagnosis is made, the most common causes of persistent microscopic hematuria are thin basement membrane nephropathy, immunoglobulin A nephropathy, or idiopathic hypercalciuria. Treatment and long-term prognosis varies with the underlying disease.

Imaging of Kidney Cysts and Cystic Kidney Diseases in Children: An International Working Group Consensus Statement

Kidney cysts can manifest as focal disease (simple and complex kidney cysts), affect a whole kidney (eg, multicystic dysplastic kidney or cystic dysplasia), or manifest as bilateral cystic disease (eg, autosomal recessive polycystic kidney disease [ARPKD] or autosomal dominant polycystic kidney disease [ADPKD]). In children, as opposed to adults, a larger proportion of kidney cysts are due to genetic diseases (eg, HNF1B nephropathy, various ciliopathies, and tuberous sclerosis complex), and fewer patients have simple cysts or acquired cystic kidney disease. The purpose of this consensus statement is to provide clinical guidance on standardization of imaging tests to evaluate kidney cysts in children. A committee of international experts in pediatric nephrology, pediatric radiology, pediatric US, and adult nephrology prepared systematic literature reviews and formulated recommendations at a consensus meeting. The final statement was endorsed by the European Society of Pediatric Radiology, the European Federation of Societies for Ultrasound in Medicine and Biology, the European Society of Pediatric Nephrology, and reviewed by the European Reference Network for Rare Kidney Diseases. Main recommendations are as follows: US is the method of choice when assessing pediatric kidney cysts, with selected indications for MRI and contrast-enhanced US. CT should be avoided whenever possible because of ionizing radiation. Renal US yields essential diagnostic information in many cases. In patients with ARPKD or other ciliopathies, abdominal US is needed for diagnosis and screening of portal hypertension. US is usually sufficient for follow-up kidney imaging, but MRI can be valuable for clinical trials in patients with ADPKD or in older children with tuberous sclerosis complex to evaluate both kidney cysts and angiomyolipomas.

Long-term outcome of liver transplantation in childhood: A study of 20-year survivors

We report the results of a study of survival, liver and kidney functions, and growth with a median follow-up of 24 years following liver transplantation in childhood. From 1988 to 1993, 128 children underwent deceased donor liver transplantation (median age: 2.5 years). Twenty-year patient and graft survival rates were 79% and 64%, respectively. Raised serum aminotransferase and/or γ-glutamyl transferase activities were present in 42% of survivors after a single transplantation. Graft histology (35 patients) showed signs of chronic rejection in 11 and biliary obstruction in 5. Mean total fibrosis scores were 4.5/9 and 3/9 in patients with abnormal and normal serum liver tests, respectively. Glomerular filtration rate was <90 mL·min^-1 in 35 survivors, including 4 in end-stage renal disease who were undergoing dialysis or had undergone renal transplantation. Median final heights were 159 cm for women and 172 cm for men; final height was below the target height in 37 patients. Twenty-year survival after childhood liver transplantation may be close to 80%, and final height is within the normal range for most patients. However, chronic kidney disease or altered liver biochemistries are present in over one third of patients, which is a matter of concern for the future.

Acquired cystic kidney disease: an under-recognized condition in children with end-stage renal disease

Acquired cystic kidney disease (ACKD) is a condition that occurs predominantly in patients with end-stage renal disease (ESRD). In contrast to hereditary cystic kidney disease, ACKD is characterized by the presence of multiple small cysts in bilaterally small kidneys. Limited pediatric data suggest a high incidence (21.6-45.8%) of ACKD in children on dialysis, comparable to that in adults, with an increased frequency associated with a longer duration of dialysis. Recent research has shed light on the pathogenesis of ACKD, such as activation of proto-oncogenes. Although most patients with ACKD are asymptomatic, the condition can be complicated by renal cell carcinoma. Routine surveillance should therefore be considered in at-risk populations.

Acquired Multiple Cysts of the Kidney in Neuroblastoma Survivors

Cystic kidney disease includes a wide range of hereditary, developmental, and acquired conditions of the kidneys. Some of the inherited causes of cystic kidney disease include autosomal dominant polycystic kidney diseases (caused by mutations in PKD1 or PKD2), autosomal recessive polycystic kidney disease, tuberous sclerosis complex, von Hippel-Lindau disease, oral-facial-digital syndrome type I, and Hadju-Cheney syndrome. Acquired cystic kidney disease has been reported in patients receiving long-term hemodialysis or peritoneal dialysis and in children after liver transplantation. Acute kidney injury can occur in patients with neuroblastoma, usually as a result of thrombotic microangiopathy associated with bone marrow transplantation. End-stage renal disease is described in long-term survivors. However, in this case report, we provide what is to our knowledge the first description of multiple kidney cysts in long-term survivors of stage IV neuroblastoma. None of the 7 patients we describe with neuroblastoma and multiple kidney cysts had a family history of autosomal dominant polycystic kidney disease. Also, all lacked stigmata of tuberous sclerosis complex, von Hippel-Lindau disease, or Hadju-Cheney syndrome. Two patients progressed to end-stage renal disease; in addition, one of them developed an oncocytoid renal cell carcinoma.

The kidney in pediatric liver transplantation: an updated perspective

CKD continues to detract from the success of improved survival in pediatric liver transplantation, and its presence is likely under recognized. Here we review the literature regarding the prevalence, etiology, and management of renal dysfunction in pediatric liver transplant recipients. Long-term studies suggest the prevalence of CKD to be 25-38% by 5-10 yr post-transplant. While important, sole use of serum creatinine overestimates renal function in this population. Screening for and treatment of persistent proteinuria and hypertension as well as minimization of nephrotoxic insults are the mainstays to delay or prevent CKD progression. Office-based blood pressure measures are less sensitive than ABPM, which is specifically recommended by the American Heart Association for its ability to diagnose masked hypertension in pediatric liver transplant recipients. Long-term risk of CKD is predominantly secondary to CNI toxicity. CNI minimization protocols have shown promise in slowing progression of CKD while maintaining graft function, but large-scale randomized control trials with long-term follow-up are needed.

Cyclic nucleotide signaling in polycystic kidney disease

Increased levels of 3'-5'-cyclic adenosine monophosphate (cAMP) stimulate cell proliferation and fluid secretion in polycystic kidney disease. Levels of this molecule are more sensitive to inhibition of phosphodiesterases (PDEs), whose activity far exceeds the rate of cAMP synthesis by adenylyl cyclase. Several PDEs exist, and here we measured the activity and expression of PDE families, their isoforms, and the expression of downstream effectors of cAMP signaling in the kidneys of rodents with polycystic kidney disease. We found a higher overall PDE activity in kidneys from mice as compared with rats, as well as a higher contribution of PDE1, relative to PDE4 and PDE3, to total PDE activity of kidney lysates and lower PDE1, PDE3, and PDE4 activities in the kidneys of cystic as compared with wild-type mice. There were reduced amounts of several PDE1, PDE3, and PDE4 proteins, possibly due to increased protein degradation despite an upregulation of their mRNA. Increased levels of cGMP were found in the kidneys of cystic animals, suggesting in vivo downregulation of PDE1 activity. We found an additive stimulatory effect of cAMP and cGMP on cystogenesis in vitro. Cyclic AMP-dependent protein kinase subunits Ialpha and IIbeta, PKare, the transcription factor CREB-1 mRNA, and CREM, ATF-1, and ICER proteins were upregulated in the kidneys of cystic as compared with wild-type animals. Our study suggests that alterations in cyclic nucleotide catabolism may render cystic epithelium particularly susceptible to factors acting on Gs-coupled receptors. This may account, in part, for increased cyclic nucleotide signaling in polycystic kidney disease and contribute substantially to disease progression.

Acquired renal cysts after pediatric liver transplantation: association with cyclosporine and renal dysfunction

ACKD has been observed in children on dialysis and with chronic renal insufficiency. In one report, ACKD was observed in 30% of pediatric liver transplant recipients after 10 yr. We retrospectively reviewed all renal imaging and measurements of GFR of 235 childhood liver transplant recipients with no known risk for renal cyst formation, no evidence of renal cyst(s) at the time of transplantation and renal imaging at least one yr post-transplant. Twenty-six patients (11%) developed one or more cyst(s). Mean GFR was significantly lower in patients with renal cyst(s). Two (1.4%) of the 146 patients treated with tacrolimus and 24 (27%) of the 89 patients treated with CsA acquired renal cyst(s) (p < 0.001). CsA-treated patients had significantly lower GFR. Multivariate analysis identified CsA as the only independent variable associated with ACKD. These results confirm that ACKD can be a late complication of pediatric liver transplantation. Those at most risk are at least 10-yr post-liver transplantation, have been treated with CsA and have impaired renal function. We speculate that ACKD in these patients is the result of calcineurin inhibitor nephrotoxicity. Whether patients with ACKD will be prone to develop solid renal tumors is unknown.