Morbidity from congenital hepatic fibrosis after renal transplantation for autosomal recessive polycystic kidney disease

Short-Term Outcome of Isolated Kidney Transplantation in Children with Autosomal Recessive Polycystic Kidney Disease: A Case Series and Literature Review

Autosomal recessive polycystic kidney disease (ARPKD) is often associated with hepatobiliary disease in the form of hepatic fibrosis and/or Caroli disease. Combined liver-kidney transplantation (CLKT) is a transplant modality of choice in children with both end-stage renal disease (ESRD) and severe hepatic disease. However, there is no consensus on whether children with ARPKD-associated ESRD without severe hepatic disease can be treated with isolated kidney transplantation (KT) without the need for CLKT. We retrospectively studied the efficacy of isolated KT in children with ARPKD without severe hepatic disease, and followed the course of hepatic disease post KT. This is a single-center study of three children with ARPKD and ESRD who underwent isolated KT. None of them had severe hepatic disease at the time of KT. All children were clinically diagnosed with ARPKD in the immediate postnatal period. All had hepatic fibrosis of varying degrees and two had intrahepatic biliary duct (IHBD) dilatation. None had gastrointestinal (GI) bleed, portal hypertension or cholangitis. Two children had preemptive KT. Pre-transplant unilateral or bilateral native nephrectomy were performed for two children, and one underwent unilateral native nephrectomy at the time of KT. The median creatinine clearance at a median post-KT follow-up of 24 months was 60.3 mL/min/1.73 m2. The two-year graft and patient survival were both 100%. Post KT, all three patients continued to demonstrate evidence of hepatic fibrosis and IHBD on sonogram; however, none of them were either evaluated for or required liver transplantation given normal synthetic liver function and absence of portal hypertension or other severe hepatobiliary disease. There were no adverse events observed such as cholangitis, GI bleed, or multiorgan failure. Hence, an excellent short-term graft and patient survival was demonstrated in this study of children with ARPKD and mild to moderate hepatic disease who received isolated KT. Long-term follow-up and larger studies are important to assess the efficacy of isolated KT in this subset of children with ARPKD.

Phenotypic Variability in Siblings with Autosomal Recessive Polycystic Kidney Disease

Introduction

Autosomal recessive polycystic kidney disease (ARPKD) is a rare monogenic disorder characterized by early onset fibrocystic hepatorenal changes. Previous reports have documented pronounced phenotypic variability even among siblings in terms of patient survival. The underlying causes for this clinical variability are incompletely understood.

Methods

We present the longitudinal clinical courses of 35 sibling pairs included in the ARPKD registry study ARegPKD, encompassing data on primary manifestation, prenatal and perinatal findings, genetic testing, and family history, including kidney function, liver involvement, and radiological findings.

Results

We identified 70 siblings from 35 families with a median age of 0.7 (interquartile range 0.1–6.0) years at initial diagnosis and a median follow-up time of 3.5 (0.2–6.2) years. Data on PKHD1 variants were available for 37 patients from 21 families. There were 8 patients from 7 families who required kidney replacement therapy (KRT) during follow-up. For 44 patients from 26 families, antihypertensive therapy was documented. Furthermore, 37 patients from 24 families had signs of portal hypertension with 9 patients from 6 families having substantial hepatic complications. Interestingly, pronounced variability in the clinical course of functional kidney disease was documented in only 3 sibling pairs. In 17 of 20 families of our cohort of neonatal survivors, siblings had only minor differences of kidney function at a comparable age.

Conclusion

In patients surviving the neonatal period, our longitudinal follow-up of 70 ARPKD siblings from 35 families revealed comparable clinical courses of kidney and liver diseases in most families. The data suggest a strong impact of the underlying genotype.

Long-term kidney and liver outcome in 50 children with autosomal recessive polycystic kidney disease

BACKGROUND

Autosomal recessive polycystic kidney disease (ARPKD) is a rare ciliopathy characterized by congenital hepatic fibrosis and cystic kidney disease. Lack of data about long-term follow-up makes it difficult to discuss timing and type of organ transplantation. Our objectives were to evaluate long-term evolution and indications for transplantation, from birth to adulthood.

METHODS

Neonatal survivors and patients diagnosed in postnatal period with ARPKD between 1985 January and 2017 December from 3 French pediatric centers were retrospectively enrolled in the study.

RESULTS

Fifty patients with mean follow-up 12.5 ± 1 years were enrolled. ARPKD was diagnosed before birth in 24%, and at mean age 1.8 years in others. Thirty-three patients were < 1 year of age at first symptoms, which were mostly kidney-related. These most often presented high blood pressure during follow-up. Portal hypertension was diagnosed in 29 patients (58%), 4 of them with bleeding from esophageal varices. Eight patients presented cholangitis (> 3 episodes in three children). Liver function was normal in all patients. Nine children received a kidney transplant without liver complications. A 20-year-old patient received a combined liver-kidney transplant (CLKT) for recurrent cholangitis, and a 15-year-old boy an isolated liver transplant for uncontrollable variceal bleeding despite portosystemic shunt.

CONCLUSIONS

Long-term outcome in patients with ARPKD is heterogeneous, and in this cohort did not depend on age at diagnosis except for blood pressure. Few patients required liver transplantation. Indications for liver or combined liver-kidney transplantation were limited to recurrent cholangitis or uncontrollable portal hypertension. Liver complications after kidney transplantation were not significant.

Combined liver and kidney transplantation in children and long-term outcome

Combined liver-kidney transplantation (CLKT) is a rarely performed complex surgical procedure in children and involves transplantation of kidney and either whole or part of liver donated by the same individual (usually a cadaver) to the same recipient during a single surgical procedure. Most common indications for CLKT in children are autosomal recessive polycystic kidney disease and primary hyperoxaluria type 1. Atypical haemolytic uremic syndrome, methylmalonic academia, and conditions where liver and renal failure co-exists may be indications for CLKT. CLKT is often preferred over sequential liver-kidney transplantation due to immunoprotective effects of transplanted liver on renal allograft; however, liver survival has no significant impact. Since CLKT is a major surgical procedure which involves multiple and complex anastomosis surgeries, acute complications are not uncommon. Bleeding, thrombosis, haemodynamic instability, infections, acute cellular rejections, renal and liver dysfunction are acute complications. The long-term outlook is promising with over 80% 5-year survival rates among those children who survive the initial six-month postoperative 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.

Individualized concept for the treatment of autosomal recessive polycystic kidney disease with end-stage renal disease

Management of children with autosomal recessive polycystic kidney disease (ARPKD) who develop end-stage renal disease (ESRD) remains challenging because of concomitant liver disease. Patients with recurrent cholangitis are candidates for liver-kidney transplantation, while the treatment for patients with splenomegaly and pancytopenia due to portal hypertension is controversial. Herein, we report 7 children who were treated using an individualized treatment strategy stratified by liver disease. Two patients with recurrent cholangitis underwent sequential liver-kidney transplantation, while 4 patients with splenomegaly and pancytopenia but without recurrent cholangitis underwent splenectomy followed by isolated kidney transplantation. The remaining patient, who did not have cholangitis and pancytopenia, underwent isolated kidney transplantation. Blood cell counts were normalized after splenectomy was performed at the median age of 8.7 (range, 7.4-11.7) years. Kidney transplantation was performed at the median age of 8.8 (range, 1.9-14.7) years in all patients. Overwhelming post-splenectomy infections and cholangitis did not occur during the median follow-up period of 6.3 (range, 1.0-13.2) years. The estimated glomerular filtration rate at the last follow-up was 53 (range, 35-107) mL/min/1.73 m² . No graft loss occurred. Our individualized treatment strategy stratified by recurrent cholangitis and pancytopenia can be a feasible strategy for children with ARPKD who develop ESRD and warrants further evaluation.

Living donor liver transplantation for congenital hepatic fibrosis in children

Congenital hepatic fibrosis (CHF) often accompanies autosomal recessive polycystic kidney disease (ARPKD), which stems from a PKHD1 gene mutation. The aim of this study was to clarify the prognosis of children with CHF who received living donor liver transplantation (LDLT) from donors who might be heterozygous carriers of a hepatorenal fibrocystic disease. Fourteen children with CHF who underwent LDLT at our center were enrolled. Eight and two patients had ARPKD and nephronophthisis, respectively. Eight of the donors were the recipients' fathers, and six donors were their mothers. We examined the histological and radiological findings of the donor livers and complications in the recipients following the liver transplantation. Seven of the donor livers presented morphological abnormalities of the bile ducts. Abdominal computed tomography revealed liver cysts in eight donors. One recipient underwent re-LT for graft failure due to rejection. Three patients presented with rejection, and one presented with sepsis. The overall survival rate was 100% and the original graft survival rate was 93%. In conclusion, the prognosis of recipients who received a LDLT from their parents for CHF was excellent. However, the morphology of half the donor livers was abnormal. Careful follow-up is needed to ensure long-term graft survival.

Neonatal polycystic kidney disease, a potential life-threatening condition at this age: A case report

RATIONALE

Autosomal recessive polycystic kidney disease (ARPKD) is a severe rare genetic condition, with high mortality rates and autosomal recessive pattern of transmission similar to most early onset cystic kidney diseases. The mortality rates can reach up to 30% during the neonatal period.

PATIENT CONCERNS

We report a case of a 27-day-old male neonate admitted in our clinic for fever, foul-smelling urine, and diarrhea. A previous abdominal ultrasound at the age of 2 weeks revealed enlarged, hyperechoic kidneys, no abnormalities of the urinary exam. Clinical examination revealed poor general status, ill-looking face, diminished cutaneous turgor, distended abdomen, and palpable kidneys. Laboratory tests pointed out leukopenia, anemia, border-line platelet count, elevated inflammatory biomarker level, hyponatremia, hypoalbuminemia, proteinuria, leukocyturia, and hematuria. Both urine and blood cultures were positive for E. coli.

DIAGNOSES

Abdominal ultrasound revealed bilateral nephromegaly, diminished parenchymatous index, with the absence of differentiation between the cortex and medulla. Abdominal MRI described bilateral nephromegaly, the hypertrophy comprising especially the structures of Malpighi pyramids, with multiple cystic lesions disseminated within both kidneys, projected also in Malpighi pyramids, their diameters ranging between 2 and 7 mm. Thus, our final diagnoses were polycystic kidney disease and sepsis due to urinary tract infection with E. coli.

INTERVENTIONS

After treating the infection, the patient was referred to a more experienced center for appropriate management of polycystic kidney disease.

OUTCOMES

The progress of the patient until the age of 1 year and 2 months has been remarkably favorable, presenting first-degree chronic kidney disease, with normal blood parameters and controlled blood pressure values, no other episodes of urinary infection, and without supplementary pathological changes in ultrasound.

LESSONS

Despite the poor prognosis of PKD reported in the literature, our case had an outstandingly favorable evolution during the first 2 years of life most-likely due to the early diagnosis and treatment, but also proper monitoring.

Ruptured intracranial aneurysm in a patient with autosomal recessive polycystic kidney disease

Aneurysmal rupture can result in devastating neurological consequences and can be complicated by comorbid disease processes. Patients with autosomal recessive polycystic kidney disease (ARPKD) have a low rate of reported aneurysms, but this may be due to the relative high rate of end-stage illnesses early in childhood. Authors here report the case of a 10-year-old boy with ARPKD who presented with a Hunt and Hess grade V subarachnoid hemorrhage requiring emergency ventriculostomy, embolization, and decompressive craniectomy. Despite initial improvements in his neurological status, the patient succumbed to hepatic failure. Given the catastrophic outcomes of subarachnoid hemorrhage in young patients, early radiographic screening in those with ARPKD may be warranted.

Successful long-term outcome of pediatric liver-kidney transplantation: a single-center study

INTRODUCTION

Liver-kidney transplantation is a rare procedure in children, with just ten to 30 cases performed annually worldwide. The main indications are autosomal recessive polycystic liver-kidney disease and primary hyperoxaluria. This study aimed to report outcomes of liver-kidney transplantation in a cohort of pediatric patients.

METHODS

We retrospectively analyzed all pediatric liver-kidney transplantations performed in our center between September 2000 and August 2015. Patient data were obtained by reviewing inpatient and outpatient medical records and our transplant database.

RESULTS

A total of 14 liver-kidney transplants were performed during the study period, with a median patient age and weight at transplant of 144.4 months (131.0-147.7) and 27.3 kg (12.0-45.1), respectively. The indications for liver-kidney transplants were autosomal recessive polycystic liver-kidney disease (8/14), primary hyperoxaluria -1 (5/14), and idiopathic portal hypertension with end-stage renal disease (1/14). Median time on waiting list was 8.5 months (5.7-17.3). All but two liver-kidney transplants were performed simultaneously. Patients with primary hyperoxaluria-1 tended to present a delayed recovery of renal function compared with patients transplanted for other indications (62.5 vs 6.5 days, respectively, P 0.076). Patients with liver-kidney transplants tended to present a lower risk of acute kidney rejection than patients transplanted with an isolated kidney transplant (7.2% vs 32.7%, respectively; P < 0.07). Patient and graft survival at 1, 3, and 5 years were 100%, 91.7%, 91.7%, and 91.7%, 83.3%, 83.3%, respectively. No other grafts were lost.

CONCLUSION

Long-term results of liver-kidney transplants in children are encouraging, being comparable with those obtained in isolated liver transplantation.

Combined and sequential liver-kidney transplantation in children

Combined and sequential liver-kidney transplantation (CLKT and SLKT) is a definitive treatment in children with end-stage organ failure. There are two major indications: - terminal insufficiency of both organs, or - need for transplanting new liver as a source of lacking enzyme or specific regulator of the immune system in a patient with renal failure. A third (uncommon) option is secondary end-stage renal failure in liver transplant recipients. These three clinical settings use distinct qualification algorithms. The most common indications include primary hyperoxaluria type 1 (PH1) and autosomal recessive polycystic kidney disease (ARPKD), followed by liver diseases associated with occasional kidney failure. Availability of anti-C5a antibody (eculizumab) has limited the validity of CLKT in genetic atypical hemolytic uremic syndrome (aHUS). The liver coming from the same donor as renal graft (in CLKT) is immunologically protective for the kidney and this provides long-term rejection-free follow-up. No such protection is observed in SLKT, when both organs come from different donors, except uncommon cases of living donation of both organs. Overall long-term outcome in CLKT in terms of graft survival is good and not different from isolated liver or kidney transplantation, however patient survival is inferior due to complexity of this procedure.

Risk Factors for Neurocognitive Functioning in Children with Autosomal Recessive Polycystic Kidney Disease

This mini review provides an overview of the issues and challenges inherent in autosomal recessive polycystic kidney disease (ARPKD), with a particular focus on the neurological factors and neurocognitive functioning of this population. ARPKD typically is discovered at the end of pregnancy or during the neonatal developmental period and occurs in approximately 1 in 20,000 live births. During the neonatal period, there is a relatively high risk of death, with many infants dying from respiratory failure. As the child ages, they experience progressive kidney disease and become increasingly vulnerable to liver disease, with many individuals eventually requiring dual organ transplants. This mini review provides a brief description of ARPKD and describes the various factors that place children with ARPKD at risk for neurological and neuropsychological impairment (e.g., a genetic condition leading to chronic kidney disease and eventual transplant; difficult-to-treat hypertension; eventual liver disease; possible dual transplantation of the kidneys and liver; chronic lung disease), including that these factors are present during a critical period of brain development. Further, the mini review discusses the available studies that have addressed the neurocognitive functioning in children with ARPKD. This paper concludes by providing the key clinical and research challenges that face the field of pediatric nephrology with respect to the clinical and scientific study of the neurocognitive functioning of children with ARPKD. Selected directions are offered in both the clinical and research arenas for this multiorgan chronic condition.

Kidney Versus Combined Kidney and Liver Transplantation in Young People With Autosomal Recessive Polycystic Kidney Disease: Data From the European Society for Pediatric Nephrology/European Renal Association-European Dialysis and Transplant (ESPN/ERA-EDTA) Registry

BACKGROUND

The choice for either kidney or combined liver-kidney transplantation in young people with kidney failure and liver fibrosis due to autosomal recessive polycystic kidney disease (ARPKD) can be challenging. We aimed to analyze the characteristics and outcomes of transplantation type in these children, adolescents, and young adults.

STUDY DESIGN

Cohort study.

SETTING & PARTICIPANTS

We derived data for children, adolescents, and young adults with ARPKD with either kidney or combined liver-kidney transplants for 1995 to 2012 from the ESPN/ERA-EDTA Registry, a European pediatric renal registry collecting data from 36 European countries.

FACTOR

Liver transplantation.

OUTCOMES & MEASUREMENTS

Transplantation and patient survival.

RESULTS

202 patients with ARPKD aged 19 years or younger underwent transplantation after a median of 0.4 (IQR, 0.0-1.4) years on dialysis therapy at a median age of 9.0 (IQR, 4.1-13.7) years. 32 (15.8%) underwent combined liver-kidney transplantation, 163 (80.7%) underwent kidney transplantation, and 7 (3.5%) were excluded because transplantation type was unknown. Age- and sex-adjusted 5-year patient survival posttransplantation was 95.5% (95% CI, 92.4%-98.8%) overall: 97.4% (95% CI, 94.9%-100.0%) for patients with kidney transplantation in contrast to 87.0% (95% CI, 75.8%-99.8%) with combined liver-kidney transplantation. The age- and sex-adjusted risk for death after combined liver-kidney transplantation was 6.7-fold (95% CI, 1.8- to 25.4-fold) greater than after kidney transplantation (P=0.005). Five-year death-censored kidney transplant survival following combined liver-kidney and kidney transplantation was similar (92.1% vs 85.9%; P=0.4).

LIMITATIONS

No data for liver disease of kidney therapy recipients.

CONCLUSIONS

Combined liver-kidney transplantation in ARPKD is associated with increased mortality compared to kidney transplantation in our large observational study and was not associated with improved 5-year kidney transplant survival. Long-term follow-up of both kidney and liver involvement are needed to better delineate the optimal transplantation strategy.

Combined liver and kidney transplantation and kidney after liver transplantation in children: Indication, postoperative outcome, and long-term results

CLKT and sequential KALT are decided on a case-by-case basis in children for special indications such as ARPKD or PH1. We report on 21 children who underwent CLKT or KALT at our hospital between 1998 and 2013. Eleven children were diagnosed with PH1 and six with ARPKD. Other diagnosis were Joubert syndrome (n = 1), nephronophthisis (n = 1), CF (n = 1), and hepatocellular carcinoma (n = 1). Children (12 males, nine females) were aged 7.8 ± 6.2 yr (range, 10 months to 18 yr) at time of transplantation. Average wait time was 1.9 ± 0.9 yr (range, four months to 2.3 yr). Fifteen patients received dialysis prior to transplantation. In PH1 patients, four children received CLKT, five received KALT, and two infants have received only an LTx, whereas all six patients with ARPKD received CLKT. In patients with other indications, CLKT was performed in three cases and KALT in one girl. Cumulative 10-yr survival of all 21 patients was 78.4%. At the time of transfer into adult care, 13 patients retained stable liver and kidney function. Regardless the underlying diagnosis, CLKT and KALT can be performed in children with good surgical outcomes and long-term survival.

Transplantation in autosomal recessive polycystic kidney disease: liver and/or kidney?

Autosomal recessive polycystic kidney disease (ARPKD) is characterized by enlarged kidneys with dilated collecting ducts and congenital hepatic fibrosis. There is a variable rate of progression of kidney and liver disease. Portal hypertension and Caroli's disease occur from liver involvement that contributes to morbidity and mortality. Approximately 40 % of patients have a severe disease phenotype leading to rapid onset of end-stage kidney disease (ESKD) and signs of portal hypertension and the rest may have predominant involvement of either the kidney or liver. It is important for the physician to establish the extent of organ involvement before deciding on the ultimate plan of management, especially when transplantation is required. Isolated renal transplantation can be considered when liver involvement is minimal. If hepatobiliary disease is prominent, and kidney function is preserved, management options are based on individual characteristics. In the presence of significant liver disease and ESKD, consideration should be given to combined liver kidney transplantation, which can be beneficial in eliminating the consequences of both kidney and liver disease. However, this is a complex surgical procedure that needs to be performed at experienced transplant centers. Improvement in surgical techniques has considerably improved short-term graft survival with the added advantage of the liver offering immunologic protection to the kidney allograft.

Kidney and liver transplantation in children with fibrocystic liver-kidney disease: data from the US Scientific Registry of Transplant Recipients: 1990-2010

The natural history and survival of children with fibrocystic liver-kidney disease undergoing solid organ transplantation have infrequently been described. We report outcomes in a cohort of US children with fibrocystic liver-kidney disease receiving solid organ transplants over 20 yr. Retrospective cohort study of pediatric transplant recipients with diagnoses of fibrocystic liver-kidney disease from 1/1990 to 3/2010, using data from the SRTR. Subjects were categorized by the first transplanted organ: LT, KT, or SLK. Primary outcomes were death, re-transplant, transplant of the alternate organ, or initiation of dialysis. Seven hundred and sixteen subjects were transplanted in this period. Median age at first transplant was 9.7 yr. Of the LT, 14 (19%) required a second liver transplant at median of 0.2 yr, and five (7%) required kidney transplant or dialysis at a median of 9.0 yr. Of the KT, 188 (31%) required a second kidney transplant or dialysis at a median of 5.9 yr. Twenty-nine (5%) subsequently received liver transplant at a median of 6.0 yr. Among patients in this registry, far more children underwent kidney than liver transplants. The risk of subsequently needing transplantation of an alternate organ was low.

Neonatal polycystic kidney disease

This article provides an up-to-date comprehensive review and summary on neonatal polycystic kidney disease (PKD) with emphasis on the differential diagnosis, clinical manifestations, diagnostic techniques, and potential therapeutic approaches for the major causes of neonatal PKD, namely hereditary disease, including autosomal recessive and autosomal dominant PKD and nonhereditary PKD, with particular emphasis on multicystic dysplastic kidney. A brief overview of obstructive cystic dysplasia and simple and complex cysts is also included.

Autosomal recessive polycystic kidney disease: a hepatorenal fibrocystic disorder with pleiotropic effects

Autosomal recessive polycystic kidney disease (ARPKD) is an important cause of chronic kidney disease in children. The care of ARPKD patients has traditionally been the realm of pediatric nephrologists; however, the disease has multisystem effects, and a comprehensive care strategy often requires a multidisciplinary team. Most notably, ARPKD patients have congenital hepatic fibrosis, which can lead to portal hypertension, requiring close follow-up by pediatric gastroenterologists. In severely affected infants, the diagnosis is often first suspected by obstetricians detecting enlarged, echogenic kidneys and oligohydramnios on prenatal ultrasounds. Neonatologists are central to the care of these infants, who may have respiratory compromise due to pulmonary hypoplasia and massively enlarged kidneys. Surgical considerations can include the possibility of nephrectomy to relieve mass effect, placement of dialysis access, and kidney and/or liver transplantation. Families of patients with ARPKD also face decisions regarding genetic testing of affected children, testing of asymptomatic siblings, or consideration of preimplantation genetic diagnosis for future pregnancies. They may therefore interface with genetic counselors, geneticists, and reproductive endocrinologists. Children with ARPKD may also be at risk for neurocognitive dysfunction and may require neuropsychological referral. The care of patients and families affected by ARPKD is therefore a multidisciplinary effort, and the general pediatrician can play a central role in this complex web of care. In this review, we outline the spectrum of clinical manifestations of ARPKD and review genetics of the disease, clinical and genetic diagnosis, perinatal management, management of organ-specific complications, and future directions for disease monitoring and potential therapies.

Liver disease in autosomal recessive polycystic kidney disease: clinical characteristics and management in relation to renal failure

OBJECTIVES

We correlated liver and kidney manifestations in a national cohort of patients with autosomal recessive polycystic kidney disease (ARPKD).

METHODS

A total of 27 consecutive patients with ARPKD were included. Hepatobiliary disorders were comparatively evaluated in 2 groups: children in group 1 (n = 10) displayed renal failure as infants and those in group 2 (n = 17) had normal kidney function through the first year of life.

RESULTS

Median follow-up time was 10.6 (range, 0.4-40) years. Portal hypertension was diagnosed in 13 patients (48%) at the median age 5.0 (1.5-27.9) years. Esophageal varices developed in 8 patients (30%) at age 8.0 (2.1-11.9) years; 4 patients (15%) had variceal bleeding, and hypersplenism/splenomegaly occurred in 52%, similarly in both groups. Biliary tract dilatation was detected at 2.8 years in group 1 and at 7.9 years in group 2, significantly more frequently in group 1 (60% vs 18%, P = 0.039), causing cholangitis in 2 (20%) versus none in group 2 (P = 0.055). A total of 10 patients (37%) underwent cadaveric liver transplantation (LT) at a median age of 6.6 (1.0-20.0) years. In 1 patient LT was performed because of hepatoblastoma. Nine of these were combined liver-kidney transplantations (CLKT). Patients in group 1 required LT earlier (4.1 years vs 18.2 years, P = 0.017) and more frequently (70% vs 18%, P = 0.01). Overall survival beyond neonatal period was 85%. Two patients died because of infectious complications after CLKT, and 1 patient because of recurrent hepatoblastoma.

CONCLUSIONS

Although correlation of renal and liver manifestations was variable, biliary dilatation was associated with early renal failure. CLKT may be a treatment for patients with ARPKD with marked hepatobiliary complications.

Combined liver and kidney transplantation in children

Simultaneous combined liver-kidney transplantation (CLKT) is a rare operation in pediatric patients so that annually only 10-30 operations are performed worldwide. The main indications for CLKT are primary hyperoxaluria type 1 and autosomal recessive polycystic kidney disease. In addition, CLKT is indicated in individual patients with metabolic or cirrhotic liver diseases and end-stage kidney disease. The surgery and immediate post-operative management of CLKT remain challenging in infants and small children. The patients should be operated on before they become severely ill or develop major systemic manifestations of their metabolic disorder. The liver allograft is immunologically protective of the kidney graft in simultaneous CLKT, often resulting in well-preserved kidney function. The long-term outcome after CLKT is nowadays comparable to that of isolated liver and kidney transplantations.

Phenotypic variation and long-term outcome in children with congenital hepatic fibrosis

BACKGROUND AND OBJECTIVE

Congenital hepatic fibrosis (CHF) and Caroli syndrome are frequently associated with renal cystic diseases. They have a variable clinical course, and the natural history is not well defined despite molecular advances. Our study describes the clinical manifestations and long-term outcome in children with this disorder.

METHODS

A retrospective case review of children with CHF at a single centre diagnosed on the basis of clinical features, radiological and endoscopic evidence of portal hypertension (PHT), and compatible histopathological findings. Children were categorised based on hepatic phenotype-group 1 (Caroli syndrome) and group 2 (CHF). Hepatobiliary as well as renal manifestations were recorded at presentation, and their evolution followed up until transplant or last follow-up.

RESULTS

There were 40 children (22 boys) with a median age of 1.3 years at clinical presentation. Fourteen of 40 (35%) children presented in the neonatal period with primarily renal disease, of whom 11 (78%) had Caroli syndrome (P = 0.02). Significant PHT with oesophageal varices was seen in 86%, with no difference in the incidence of gastrointestinal bleeding and varices between Caroli syndrome and CHF. Cholangitis developed in 10 of 40 (25%) and was more common in the Caroli syndrome group (P = 0.009). A higher proportion of children with Caroli syndrome developed chronic kidney disease (CKD) stage 3 and above as compared with CHF (85% vs 42%; P = 0.007). Twelve of 21 (57%) and 8 of 19 (42%) children in the Caroli syndrome and CHF groups required either combined liver-kidney or isolated liver transplant, with the most common indication for renal transplantation being end-stage renal disease (CKD5d) with or without advanced PHT or cholangitis. All 14 (100%) children with neonatal presentation developed CKD5d and required combined liver-kidney transplant before 14 years of age, whereas 77% of children presenting beyond the neonatal period survived without liver-kidney transplant (P < 0.001). Neonatal presentation was the best predictor of the need for transplant.

CONCLUSIONS

Caroli syndrome is more likely to present in the neonatal period and these patients are more likely to develop CKD5d. CKD stage 3 or above with recurrent cholangitis is more common in Caroli syndrome presenting beyond the neonatal period and adds to the significant morbidity in these patients. Children presenting in the neonatal period have a more severe phenotype and should be considered early for combined liver-kidney transplant.

New approaches to the autosomal recessive polycystic kidney disease patient with dual kidney-liver complications

Improved neonatal medical care and renal replacement technology have improved the long-term survival of patients with ARPKD. Ten-yr survival of those surviving the first year of life is reported to be 82% and is continuing to improve further. However, despite increases in overall survival and improved treatment of systemic hypertension and other complications of their renal disease, nearly 50% of survivors will develop ESRD within the first decade of life. In addition to renal pathology, patients with ARPKD develop ductal plate malformations with cystic dilation of intra- and extrahepatic bile ducts resulting in CHF and Caroli syndrome. Many patients with CHF will develop portal hypertension with resulting esophageal varices, splenomegaly, hypersplenism, protein losing enteropathy, and gastrointestinal bleeding. Management of portal hypertension may require EBL of esophageal varices or porto-systemic shunting. Complications of hepatic involvement can include ascending cholangitis, cholestasis with malabsorption of fat-soluble vitamins, and rarely benign or malignant liver tumors. Patients with ARPKD who eventually reach ESRD, and ultimately require kidney transplantation, present a unique set of complications related to their underlying hepato-biliary disease. In this review, we focus on new approaches to these challenging patients, including the indications for liver transplantation in ARPKD patients with severe chronic kidney disease awaiting kidney transplant. While survival in patients with ARPKD and isolated kidney transplant is comparable to that of age-matched pediatric patients who have received kidney transplants due to other primary renal diseases, 64-80% of the mortality occurring in ARPKD kidney transplant patients is attributed to cholangitis/sepsis, which is related to their hepato-biliary disease. Recent data demonstrate that surgical mortality among pediatric liver transplant recipients is decreased to <10% at one yr. The immunosuppressive regimen used for kidney transplant recipients is adequate for most liver transplant recipients. We therefore suggest that in a select group of ARPKD patients with recurrent cholangitis or complications of portal hypertension, combined liver-kidney transplant is a viable option. Although further study is necessary to confirm our approach, we believe that combined liver-kidney transplantation can potentially decrease overall mortality and morbidity in carefully selected ARPKD patients with ESRD and clinically significant CHF.

Combined liver-kidney transplantation for children with autosomal recessive polycystic kidney disease (ARPKD): indication and outcome

In ARPKD, mutations in the PKHD1 gene lead to remodeling of the kidneys and liver. These may result in progressive liver fibrosis with portal hypertension requiring combined liver and kidney transplantation (CLKT). There is currently no consensus on the indication for CLKT and data on long-term outcomes are scarce. We analyzed in detail the pretransplant liver symptomatology, laboratory and ultrasound data, histological studies, and genotypes in eight patients undergoing CLKT. The median age was 10.1 years (range 1.7-16) and median follow-up was 4.6 years (range 1.1-8.9). All patients had clinical signs of portal hypertension and abnormal ultrasound findings. Congenital hepatic fibrosis was present in all pretransplant biopsies (6 out of 8 patients) and in all explanted livers. All patients survived; liver and kidney graft survival was 72% and 88%, respectively. Liver and kidney function were stable in all patients with a median eGFR of 70 ml/min/1.73 m² (range 45-108 ml/min/1.73 m²). Height-SDS improved significantly after 12, 24, and 36 months (P = 0.016, 0.022 and 0.018 respectively). The indication for CLKT remains challenging and controversial. A favorable outcome for patients with ARPKD can be achieved by using the degree of portal hypertension, longitudinal ultrasound examinations, and preoperative liver histology as parameters for CLKT.

A complex case of congenital cystic renal disease

This case outlines the potential complexity of autosomal recessive polycystic kidney disease (ARPKD). It highlights the challenges involved in managing this condition, some of the complications faced and areas of uncertainty in the decision making process. With a paucity of published paediatric cases on this subject, this should add to the pool of information currently available.

Congenital hepatic fibrosis and autosomal recessive polycystic kidney disease

OBJECTIVES

The published natural history of congenital hepatic fibrosis (CHF) was examined to inform clinical decision making in autosomal recessive polycystic kidney disease (ARPKD).

METHODS

A systematic literature search of the data on CHF, ARPKD, Caroli disease, Caroli syndrome, and type V choledochal cyst was performed to extract data related to portal hypertension, infection, malignancy, mortality, and transplantation.

RESULTS

Information related to 1230 patients with CHF was extracted from 155 articles. Median and mean age at diagnosis were 2 and 11.2 years, respectively. Median and mean time followed after diagnosis were 5.0 and 7.5 years, respectively (range 0-38 years). Sequelae of portal hypertension (n = 409), cholangitis (n = 152), and malignancy (n = 21) were noted. The nature of the portal hypertension was similar to that in other pediatric conditions (164 with varices, 74 bleeding varices, 81 underwent portosystemic shunting). Documented cholangitis was fatal in 3 of 23 children who were infected after renal transplantation. Twenty-one patients developed hepatobiliary cancer, with the majority having cholangiocarcinoma (n = 19). Cholangiocarcinoma (CCA) was predominant in individuals older than 40 years with either Caroli syndrome or isolated CHF, not ARPKD (median and mean age at CCA diagnosis were 70.3 and 60.1 years, respectively; range 33-75 years). There was a relative paucity of data on combined liver-kidney transplantation.

CONCLUSIONS

Clinical decision making in ARPKD should reflect an understanding of the potential issues emanating from CHF. Accepted pediatric specific approaches to portal hypertension are warranted but must take into consideration the stage of renal insufficiency and potential plans for renal transplantation. Cholangitis is a major issue and necessitates anticipatory guidance and awareness. CCA, although a dreaded complication, does not appear to be a major issue during childhood. The indications for liver and combined liver-kidney transplantation are controversial and warrant further analysis.

Pediatric liver transplantation for fibropolycystic liver disease

Fibropolycystic liver disease includes CHF, Caroli's syndrome, and Caroli's disease. Patients with Caroli's disease and Caroli's syndrome have an increased risk of recurrent cholangitis, intrahepatic calculi, biliary cirrhosis, and cholangiocarcinoma. The aim of this study was to examine the post-transplantation outcomes of children with fibropolycystic liver disease. Of the 158 children transplanted at Seoul National University Hospital, there were four patients with Caroli's syndrome, two patients with CHF, and one patient with Caroli's disease. One patient underwent combined liver/kidney transplantation. Associated renal manifestations included ARPKD in three children and nephronophthisis in one child. The indications for LT were recurrent cholangitis, decompensated cirrhosis, and refractory complications of portal hypertension. Both graft and patient survival rates were 100% at a median follow-up period of two yr after LT. Three children with growth failure achieved catch-up growth after LT. In three patients with ARPKD, mean serum creatinine levels increased from 0.53 mg/dL at the time of LT to 0.91 mg/dL at the last follow-up (p = 0.01). LT is an excellent option for children with complications from fibropolycystic liver disease. Renal function should be monitored cautiously after LT in the patients with ARPKD.

Pediatric liver-kidney transplantation for hepatorenal fibrocystic disease from a living donor

The indications for and the timing of LT and/or KT for the patients with HRFCD are based on the severity of liver and kidney involvement. Most organs come from living donors, because the number of deceased donors is extremely low in Japan. Therefore, patients with HRFCD may need two organs from living donors. Four patients with HRFCD underwent living donor LT and KT from a single donor. The type of transplantation included combined LKT in one case, sequential LKT in two cases, and sequential KLT in one case. Although the case of combined LKT died because of sepsis, the other cases were doing well. Sequential LKT was successfully performed at the proper timing for each transplant; however, both of the donors suffered from a gastroduodenal ulcer after liver donation because of the psychological burden related to the relatively short period between two donations. In conclusion, living donation for LKT with cautious surgical procedures is not harmful for donors and recipients. However, changes in the allocation system established for deceased donors for HRFCD should be considered to avoid the need for two organ donations from the same living donor.

The spectrum of polycystic kidney disease in children

Autosomal dominant polycystic kidney disease (ADPKD) and autosomal recessive polycystic kidney disease (ARPKD) are important inherited kidney diseases with distinct clinical features and genetics. Although these diseases have classically been considered "adult" (ADPKD) or "infantile/pediatric" (ARPKD), it is now clear that both diseases can present in children and adults. ADPKD and ARPKD also share important pathophysiologic features, including cilia dysfunction. ADPKD is a systemic disease involving cysts in the kidneys and abdominal organs as well as abnormalities in the heart and vasculature. Although it typically presents in adults, ADPKD has been diagnosed in fetuses, infants, children, and adolescents. The majority of children diagnosed with ADPKD are asymptomatic. Those with symptoms typically present with hypertension or gross hematuria. Routine screening for renal cysts in asymptomatic children who have a parent with ADPKD is generally not recommended. ARPKD is a disorder confined to the kidneys (polycystic kidneys) and liver (a developmental biliary lesion called congenital hepatic fibrosis). Although most children with ARPKD present in infancy with large, echogenic kidneys, a subset present later in childhood and even adulthood, primarily with complications related to the liver disease. As more patients with ARPKD survive to adulthood, these liver complications are likely to become more prevalent.

End-stage renal disease due to ARPKD in the first months of life: transplantation or dialysis?--two case reports

ARPKD with renal insufficiency during the first months of life is a clinical challenge. We report on two children with ARPKD with massively enlarged kidneys requiring renal replacement therapy in early infancy. Patient 1 developed pulmonary insufficiency due to massively enlarged kidneys. At the age of six months the girl was listed for KT as "high urgency" on the Eurotransplant waiting list. A kidney from a deceased donor was pre-emptively transplanted and simultaneous nephrectomy performed. No postoperative complications were observed, and the patient was discharged from in-patient care 42 days after transplantation. Unexpectedly, she died at the age of one yr due to cerebral vascular spasms of unknown origin. Patient 2 was transferred at the age of three months to our clinic with life-threatening pulmonary insufficiency. Pre-emptive KT was not possible; therefore, bilateral nephrectomy was performed and PD begun. The boy is still doing well on PD one yr later. Pre-emptive KT and bilateral nephrectomy followed by PD are two options for infants with ARPKD and excessive kidney enlargement. PD could be complicated and in some cases become impossible by peritoneal damage during nephrectomy. On the other hand, KT covers a high risk of infections caused by immunosuppression. The decision, which method to choose, should be driven by the individual situation of the patient and the expertise of the center.

Renin-angiotensin system activation in congenital hepatic fibrosis in the PCK rat model of autosomal recessive polycystic kidney disease

OBJECTIVES

Congenital hepatic fibrosis (CHF) is an important cause of morbidity and mortality in patients with autosomal recessive polycystic kidney disease (ARPKD). The pathogenesis of CHF remains undefined. Several recent studies suggest that the renin-angiotensin system (RAS) is an important mediator of progressive hepatic fibrosis through activation of profibrotic mediators, such as transforming growth factor-beta (TGF-beta). RAS activation has not previously been studied in patients with CHF or in animal models. The aim of the present study was to characterize RAS expression during the course of CHF in the PCK rat.

MATERIALS AND METHODS

Studies were conducted in the PCK rat, an orthologous ARPKD/CHF model, and age-matched normal control Sprague-Dawley rats. Expression of the RAS components, renin, angiotensinogen, angiotensin-converting enzyme (ACE), and angiotensin II type 1 receptor (AT1R), as well as the profibrotic mediator TGF-beta, was examined in cystic PCK and control rat livers at 2, 4, and 6 months of age by quantitative real-time polymerase chain reaction (qRT-PCR). Angiotensin II (ANG II) was examined by immunohistochemistry (IHC). Fibrosis was assessed by IHC using reticulin staining and Masson trichrome. Collagen content was determined by hydroxyproline analysis.

RESULTS

Progressive fibrosis and increased hepatic collagen content occurred in PCK rats with age. In 4- and 6-month-old PCK rat livers, ACE gene expression was markedly increased, 8- and 17-fold, respectively, compared with age-matched control livers. Expression of the other RAS components, renin, angiotensinogen, and AT1R were not significantly different. IHC demonstrated prominent ANG II protein expression in periportal regions in PCK rats. In contrast, no expression was noted in control livers. TGF-beta expression was also increased in PCK rat livers with progressive disease.

CONCLUSIONS

The present study demonstrates, for the first time, RAS upregulation in an orthologous rat ARPKD/CHF model. Increases in ACE and ANG II, as well as the downstream target, the profibrotic mediator TGF-beta, suggest that RAS activation may be an important mediator of CHF disease progression. The findings also suggest that treatment with RAS inhibitors, specifically ACE inhibitors or AT1R blockers, could be therapeutic in slowing disease progression in CHF.

Indications for combined liver and kidney transplantation in children

A significant number of patients awaiting liver transplantation have associated renal failure and renal dysfunction is associated with increased morbidity and mortality after LT. There has been a recent increase in the number of CLKT in adults. The common indications for CLKT in children are different from those of adults and include metabolic diseases affecting the kidney with or without liver dysfunction and congenital developmental abnormalities affecting both organs. The results are generally encouraging among these groups of patients. Early evaluation and listing of patients before they become severely ill or have major systemic manifestations of their metabolic problem are important.

Combined liver-kidney transplantation in children: indications and outcome

Although it remains a relatively infrequent procedure in children, CLKT has become a viable option for a select group of pediatric patients with severe liver and kidney disease. Most are performed for rare primary diseases such as PH1, but a selected few are performed in the setting of concomitant hepatic and renal failure of uncertain etiology and prognosis. This article reviews the indications for and outcomes following CLKT in children. While it focuses on the specific primary diseases which impact liver and kidney function simultaneously, it addresses the indications based on concomitant hepatic and renal failure, such as seen in the hepatorenal syndrome, as well.

Rapid evolution of congenital hepatic fibrosis after liver transplantation for acute liver failure: the potential role of extrahepatic factors

A 9-year-old male underwent deceased donor liver transplantation for idiopathic fulminant hepatic failure. In the postoperative period, a review of perioperative biopsies of the donor liver revealed mild features of congenital hepatic fibrosis. Over the ensuing year, the recipient developed severe complications of congenital hepatic fibrosis including multiple episodes of cholangitis and progressive portal hypertension. After a second transplant, the patient had no further episodes of cholangitis and/or features of portal hypertension. Examination of the explanted liver revealed remarkable progression of the congenital hepatic fibrosis, suggesting that the phenotype of this disease may be dependent in part on extrahepatic factors.

Congenital cholestatic syndromes: what happens when children grow up?

Although advances in the management of children with congenital cholestasis have enabled many to survive into adulthood with their native livers, even the most common of these conditions remains rare in adult hepatology practice. Among four congenital cholestatic syndromes (biliary atresia, Alagille syndrome, Caroli disease and congenital hepatic fibrosis, and progressive familial intrahepatic cholestasis), the published data on outcomes of the syndromes into adulthood suggest that a spectrum of severity of liver disease can be expected, from cirrhosis (almost universal in adults with biliary atresia who have not required liver transplantation) to mild and subclinical (eg, in the previously undiagnosed affected parent of an infant with Alagille syndrome). Complications associated with portal hypertension and nutritional deficiencies are common, and other associated features of the cholestatic syndrome may require appropriate attention, such as congenital heart disease in Alagille syndrome. Indications for liver transplantation include synthetic failure, progressive encephalopathy, intractable pruritus, recurrent biliary sepsis and recurrent complications of portal hypertension. Improved understanding of biliary physiology will hopefully translate into improved therapy for children and adults with cholestasis.

Successful transplantation in a child with rapid progression of autosomal recessive polycystic kidney disease associated with a novel mutation

Autosomal recessive polycystic kidney disease (ARPKD) is the most common pediatric renal cystic disease with liver involvement. The vast majority of patients with ARPKD carry mutations in the recently characterized PKHD1 gene on chromosome 6p12. A Turkish female demonstrated rapid growth of both kidneys after delivery. Accelerated growth of both kidneys and increasing respiratory distress necessitated right-sided nephrectomy at the age of three months. Because of persistent dyspnea and ongoing growth of the remaining kidney, the second kidney also had to be removed one month later. Biopsies taken from the kidney and the liver confirmed the diagnosis of ARPKD histologically. Renal ultrasound of the patient's consanguineous parents and her older brother showed normal results. PKHD1 mutation analysis yielded a novel homozygous missense mutation (c.1116C >G, F372L) in exon 14, coding for an Ig-like domain (TIG), possibly involved in the increased growth of the kidneys. Peritoneal dialysis was performed for 12 months. The patient had successful transplantation at the age of 15 months and is doing well with actual immunosuppression with cyclosporine, mycophenolate mofetil, and prednisolone. In conclusion, the present case clearly demonstrates the favorable outcome of a child with severe ARPKD after bilateral nephrectomy, pre-emptive dialysis, and successful transplantation.

Clinical and molecular characterization defines a broadened spectrum of autosomal recessive polycystic kidney disease (ARPKD)

The autosomal recessive form of polycystic kidney disease (ARPKD) is generally considered an infantile disorder with the typical presentation of greatly enlarged echogenic kidneys detected in utero or within the neonatal period, often resulting in neonatal demise. However, there is an increasing realization that survivors often thrive into adulthood with complications of the ductal plate malformation, manifesting as congenital hepatic fibrosis and Caroli disease, becoming prominent. Previous natural history studies have concentrated almost exclusively on the infantile presenting group. However, developments in understanding the genetic basis of ARPKD, through identification of the disease gene, PKHD1, have allowed exploration of the etiology in patients with ARPKD-like disease or congenital hepatic fibrosis presenting later in childhood or as adults. In the current study we retrospectively reviewed the clinical records, and where possible performed PKHD1 mutation screening, in patients diagnosed with ARPKD or congenital hepatic fibrosis at the Mayo Clinic, Rochester, MN, from 1961 to 2004. Of a total of 133 cases reviewed, 65 were considered to meet the diagnostic criteria with an average duration of follow-up of 8.6 +/- 6.4 years. Fifty-five cases had ARPKD and 10 had isolated congenital hepatic fibrosis with no or minimal renal involvement. The patients were analyzed as 3 groups categorized by the age at diagnosis; <1 years (n = 22), 1-20 years (n = 23), and >20 years (n = 20). The presenting feature in the neonates was typically associated with renal enlargement, but in the older groups, more often involved manifestations of liver disease, including hepatosplenomegaly, hypersplenism, variceal bleeding, and cholangitis. During follow-up, 22 patients had renal insufficiency and 8 developed end-stage renal disease (ESRD), most from the neonatal group. Liver disease was evident on follow-up in all diagnostic groups but particularly prevalent in those diagnosed later in life. A total of 12 patients died, 6 in the neonatal period, but 86% of patients were alive at 40 years of age. The likelihood of being alive without ESRD differed significantly between the diagnostic groups with 36%, 80%, and 88% survival in the 3 diagnostic groups, respectively, 20 years after the diagnosis. Considerable evidence of intrafamilial phenotype variability was observed. Mutation analysis was performed in 31 families and at least 1 mutation was detected in 25 (81%), with 76% of mutant alleles detected in those cases. Consistent with the relatively mild disease manifestations in this population, the majority of changes were missense (79%) and no case had 2 truncating changes. Mutations were detected in all diagnostic groups, indicating that congenital hepatic fibrosis with minimal kidney involvement can result from PKHD1 mutation. The finding of 6 cases with no detected mutations may represent missed mutations or possible evidence of genetic heterogeneity. The current study indicates a broadened spectrum for the ARPKD phenotype and that later presenting cases with predominant liver disease should be considered part of ARPKD.

Liver disease in autosomal recessive polycystic kidney disease

Hepatic complications occur in a significant proportion of children with autosomal recessive polycystic kidney disease (ARPKD). PKHD1/fibrocystin, the defective gene in ARPKD, is expressed in the cilia of bile duct epithelium and leads to abnormalities in the rubric of the ductal plate malformation. Portal hypertension and biliary disease are the major liver problems seen in ARPKD. Complete blood counting, physical examination, ultrasonography and magnetic resonance (MR) cholangiography are indicated as screening procedures for hepatic disease in ARPKD. Medical and surgical interventions are potentially indicated for children with portal hypertension and/or biliary disease. A high index of suspicion for the diagnosis of cholangitis needs to be maintained in children with biliary disease. The implications of hepatic disease need to be considered in the decision-making regarding renal transplantation in ARPKD.

A mouse model for cystic biliary dysgenesis in autosomal recessive polycystic kidney disease (ARPKD)

Autosomal recessive polycystic kidney disease (ARPKD) is an important cause of liver- and renal-related morbidity and mortality in childhood. Recently, PKHD1, the gene encoding the transmembrane protein polyductin, was shown to be mutated in ARPKD patients. We here describe the first mouse strain, generated by targeted mutation of Pkhd1. Due to exon skipping, Pkhd1ex40 mice express a modified Pkhd1 transcript and develop severe malformations of intrahepatic bile ducts. Cholangiocytes maintain a proliferative phenotype and continuously synthesize TGF-beta1. Subsequently, mesenchymal cells within the hepatic portal tracts continue to synthesize collagen, resulting in progressive portal fibrosis and portal hypertension. Fibrosis did not involve the hepatic lobules, and we did not observe any pathological changes in morphology or function of hepatocytes. Surprisingly and in contrast to human ARPKD individuals, Pkhd1ex40 mice develop morphologically and functionally normal kidneys. In conclusion,our data indicate that subsequent to formation of the embryonic ductal plate, dysgenesis of terminally differentiated bile ducts occurs in response to the Pkhd1ex40 mutation. The role of polyductin in liver and kidney may be functionally divergent, because protein domains essential for bile duct development do not affect nephrogenesis in our mouse model.

Survival of childhood polycystic kidney disease following renal transplantation: the impact of advanced hepatobiliary disease

Childhood PKD encompasses the diagnoses of AR and ADPKD, glomerulocystic disease, and syndromes such as tuberous sclerosis or Jeune's syndrome. Given the fact that a majority of PKD children with ESRD carry the diagnosis of ARPKD, natural history studies assessing the long-term prognosis of PKD patients following renal transplantation must focus on morbidity and mortality issues related to complications from congenital hepatic fibrosis. Using the NAPRTCS registry, we analyzed the patient and graft survival rates of 203 PKD patients and 7044 non-PKD patients undergoing renal transplantation between 1987 and 2001. Deceased PKD patients, all with a diagnosis of ARPKD, were further identified and characterized using a special questionnaire submitted to the principal investigators. Overall graft and patient survival rates were not significantly different between PKD and non-PKD patients. No differences in rates of acute rejection or time to first rejection were noted between PKD and non-PKD patients. The relative risk of living longer than 3 yr in the PKD patients was not significantly different from non-PKD patients (RR = 0.70, p = 0.28). Sepsis was identified as a likely factor in the cause of death in nine (64%) ARPKD patients and was comfirmed with a positive blood culture in four patients. Despite similar graft and patient survival rates among PKD and non-PKD children following renal transplantation, our results suggest that ARPKD transplant recipients appear to be at increased risk for sepsis that may be related to hepatic fibrosis and ascending cholangitis. The utility of early liver transplantation in ARPKD patients with significant hepatobiliary disease is discussed.