Long-term results of pre-emptive liver transplantation in primary hyperoxaluria type 1

Distinguishing characteristics of pediatric patients with primary hyperoxaluria type 1 in PEDSnet

BACKGROUND

Primary hyperoxaluria type 1 (PH1) is an autosomal recessive inborn error of metabolism that causes oxalate deposition, leading to recurrent calcium oxalate kidney stones, chronic kidney disease and systemic oxalosis, which produces a broad range of serious life-threatening complications. Patients with PH1 have delayed diagnosis due to the rarity of the disease and the overlap with early-onset kidney stone disease not due to primary hyperoxaluria.

OBJECTIVE

The objective of this study was to determine the clinical features of individuals <21 years of age with PH1 that precede its diagnosis. We hypothesized that a parsimonious set of features could be identified that differentiate patients with PH1 from patients with non-primary hyperoxaluria-associated causes of early-onset kidney stone disease.

STUDY DESIGN

We determined the association between clinical characteristics and PH1 diagnosis in a case-control study conducted between 2009 and 2021 in PEDSnet, a clinical research network of eight US pediatric health systems. Each patient with genetically confirmed PH1 was matched by sex and PEDSnet institution to up to 4 control patients with kidney stones without PH of any type. We obtained patient characteristics and diagnostic test results occurring before to less than 6 months after study entrance from a centralized database query and from manual chart review. Differences were examined using standardized differences and multivariable regression.

RESULTS

The study sample included 37 patients with PH1 and 147 controls. Patients with PH1 were younger at diagnosis (median age of 3 vs 13.5 years); 75 % of children with PH1 were less than 8 years-old. Patients with PH1 were more likely to have combinations of nephrocalcinosis on ultrasound or CT (43 % vs 3 %), lower eGFR at diagnosis (median = 52 mL/min/1.73 m2 vs 114 mL/min/1.73 m2), and have normal mobility. Patients with PH1 had higher proportion of calcium oxalate monohydrate kidney stones than controls (median = 100 % vs 10 %). There were no differences in diagnosis of failure to thrive, stone size, or echocardiography results.

CONCLUSIONS

Children with PH1 are characterized by presentation before adolescence, nephrocalcinosis, decreased eGFR at diagnosis, and calcium oxalate monohydrate stone composition. If externally validated, these characteristics could facilitate earlier diagnosis and treatment of children with PH1.

Effect of liver transplantation with primary hyperoxaluria type 1: Five case reports and review of literature

BACKGROUND

Primary hyperoxaluria type 1 (PH1) is a rare autosomal recessive disease stemming from a deficiency in liver-specific alanine-glyoxylate aminotransferase, resulting in increased endogenous oxalate deposition and end-stage renal disease. Organ transplantation is the only effective treatment. However, its approach and timing remain controversial.

CASE SUMMARY

We retrospectively analyzed 5 patients diagnosed with PH1 from the Liver Transplant Center of the Beijing Friendship Hospital from March 2017 to December 2020. Our cohort included 4 males and 1 female. The median age at onset was 4.0 years (range: 1.0-5.0), age at diagnosis was 12.2 years (range: 6.7-23.5), age at liver transplantation (LT) was 12.2 years (range: 7.0-25.1), and the follow-up time was 26.3 mo (range: 12.8-40.1). All patients had delayed diagnosis, and 3 patients had progressed to end-stage renal disease by the time they were diagnosed. Two patients received preemptive LT; their estimated glomerular filtration rate was maintained at > 120 mL/min/1.73 m², indicating a better prognosis. Three patients received sequential liver and kidney transplantation. After transplantation, serum and urinary oxalate decreased, and liver function recovered. At the last follow-up, the estimated glomerular filtration rates of the latter 3 patients were 179, 52 and 21 mL/min/1.73 m².

CONCLUSION

Different transplantation strategies should be adopted for patients based on their renal function stage. Preemptive-LT offers a good therapeutic approach for PH1.

PHYOX2: a pivotal randomized study of nedosiran in primary hyperoxaluria type 1 or 2

Nedosiran is an investigational RNA interference agent designed to inhibit expression of hepatic lactate dehydrogenase, the enzyme thought responsible for the terminal step of oxalate synthesis. Oxalate overproduction is the hallmark of all genetic subtypes of primary hyperoxaluria (PH). In this double-blind, placebo-controlled study, we randomly assigned (2:1) 35 participants with PH1 (n = 29) or PH2 (n = 6) with eGFR ≥30 mL/min/1.73 m² to subcutaneous nedosiran or placebo once monthly for 6 months. The area under the curve (AUC) of percent reduction from baseline in 24-hour urinary oxalate (Uox) excretion (primary endpoint), between day 90-180, was significantly greater with nedosiran vs placebo (least squares mean [SE], +3507 [788] vs -1664 [1190], respectively; difference, 5172; 95% CI 2929-7414; P < 0.001). A greater proportion of participants receiving nedosiran vs placebo achieved normal or near-normal (<0.60 mmol/24 hours; <1.3 × ULN) Uox excretion on ≥2 consecutive visits starting at day 90 (50% vs 0; P = 0.002); this effect was mirrored in the nedosiran-treated PH1 subgroup (64.7% vs 0; P < 0.001). The PH1 subgroup maintained a sustained Uox reduction while on nedosiran, whereas no consistent effect was seen in the PH2 subgroup. Nedosiran-treated participants with PH1 also showed a significant reduction in plasma oxalate versus placebo (P = 0.017). Nedosiran was generally safe and well tolerated. In the nedosiran arm, the incidence of injection-site reactions was 9% (all mild and self-limiting). In conclusion, participants with PH1 receiving nedosiran had clinically meaningful reductions in Uox, the mediator of kidney damage in PH.

Improving Treatment Options for Primary Hyperoxaluria

The primary hyperoxalurias are three rare inborn errors of the glyoxylate metabolism in the liver, which lead to massively increased endogenous oxalate production, thus elevating urinary oxalate excretion and, based on that, recurrent urolithiasis and/or progressive nephrocalcinosis. Frequently, especially in type 1 primary hyperoxaluria, early end-stage renal failure occurs. Treatment possibilities are scare, namely, hyperhydration and alkaline citrate medication. In type 1 primary hyperoxaluria, vitamin B₆, though, is helpful in patients with specific missense or mistargeting mutations. In those vitamin B₆ responsive, urinary oxalate excretion and concomitantly urinary glycolate is significantly decreased, or even normalized. In patients non-responsive to vitamin B₆, RNA interference medication is now available. Lumasiran^® is already available on prescription and targets the messenger RNA of glycolate oxidase, thus blocking the conversion of glycolate into glyoxylate, hence decreasing oxalate, but increasing glycolate production. Nedosiran blocks liver-specific lactate dehydrogenase A and thus the final step of oxalate production. Similar to vitamin B₆ treatment, where both RNA interference urinary oxalate excretion can be (near) normalized and plasma oxalate decreases, however, urinary and plasma glycolate increases with lumasiran treatment. Future treatment possibilities are on the horizon, for example, substrate reduction therapy with small molecules or gene editing, induced pluripotent stem cell-derived autologous hepatocyte-like cell transplantation, or gene therapy with newly developed vector technologies. This review provides an overview of current and especially new and future treatment options.

Randomized Clinical Trial on the Long-Term Efficacy and Safety of Lumasiran in Patients With Primary Hyperoxaluria Type 1

Introduction

Primary hyperoxaluria type 1 (PH1) is a rare genetic disease caused by hepatic overproduction of oxalate, leading to kidney stones, nephrocalcinosis, kidney failure, and systemic oxalosis. In the 6-month double-blind period (DBP) of ILLUMINATE-A, a phase 3, randomized, placebo-controlled trial in patients with PH1 ≥6 years old, treatment with lumasiran, an RNA interference therapeutic, led to substantial reductions in urinary oxalate (UOx) levels.

Methods

We report data to month 12 in the extension period (EP) of ILLUMINATE-A, including patients who continued lumasiran (lumasiran/lumasiran) or crossed over from placebo to lumasiran (placebo/lumasiran).

Results

In the lumasiran/lumasiran group (n = 24), the reduction in 24-hour UOx level was sustained to month 12 (mean reduction from baseline, 66.9% at month 6; 64.1% at month 12). The placebo/lumasiran group (n = 13) had a similar time course and magnitude of 24-hour UOx reduction (mean reduction, 57.3%) after 6 months of lumasiran. Kidney stone event rates seemed to be lower after 6 months of lumasiran in both groups compared with the 12 months before consent, and this reduction was maintained at month 12 in the lumasiran/lumasiran group. At study start, 71% of patients in the lumasiran/lumasiran group and 92% in the placebo/lumasiran group had nephrocalcinosis. Nephrocalcinosis grade improved after 6 months of lumasiran in the lumasiran/lumasiran and placebo/lumasiran groups (13% and 8% of patients, respectively). After an additional 6 months of lumasiran, 46% of patients had improvement in nephrocalcinosis grade within the lumasiran/lumasiran group. Estimated glomerular filtration rate (eGFR) remained stable during the course of lumasiran treatment. The most common adverse events (AEs) related to lumasiran were mild, transient injection-site reactions (ISRs).

Conclusion

Long-term lumasiran treatment enabled sustained lowering of UOx levels with acceptable safety and encouraging results on clinical outcomes.

Novel therapeutic approaches for the primary hyperoxalurias

Loss-of-function mutations in three genes, involved in the metabolic pathway of glyoxylate, result in increased oxalate production and its crystallization in the form of calcium oxalate. This leads to three forms of primary hyperoxaluria-an early-onset inherited kidney disease with wide phenotypic variability ranging from isolated kidney stone events to stage 5 chronic kidney disease in infancy. This review provides a description of metabolic processes resulting in oxalate overproduction and summarizes basic therapeutic approaches. Unfortunately, current treatment of primary hyperoxaluria does not allow the prevention of loss of kidney function or to substantially diminish other symptoms in most patients. However, latest breakthroughs in biotechnology provide new promising directions for drug development. Some of them have already progressed to the level of clinical trials; others are just at the stage of proof of concept. Here we review the most advanced technologies including those that have been harnessed as possible therapeutic modalities.

Transplantation outcomes in patients with primary hyperoxaluria: a systematic review

BACKGROUND

Primary hyperoxaluria type 1 (PH1) is characterized by hepatic overproduction of oxalate and often results in kidney failure. Liver-kidney transplantation is recommended, either combined (CLKT) or sequentially performed (SLKT). The merits of SLKT and the place of an isolated kidney transplant (KT) in selected patients are unsettled. We systematically reviewed the literature focusing on patient and graft survival rates in relation to the chosen transplant strategy.

METHODS

We searched MEDLINE and Embase using a broad search string, consisting of the terms 'transplantation' and 'hyperoxaluria'. Studies reporting on at least four transplanted patients were selected for quality assessment and data extraction.

RESULTS

We found 51 observational studies from 1975 to 2020, covering 756 CLKT, 405 KT and 89 SLKT, and 51 pre-emptive liver transplantations (PLT). Meta-analysis was impossible due to reported survival probabilities with varying follow-up. Two individual high-quality studies showed an evident kidney graft survival advantage for CLKT versus KT (87% vs. 14% at 15 years, p<0.05) with adjusted HR for graft failure of 0.14 (95% confidence interval: 0.05-0.41), while patient survival was similar. Three other high-quality studies reported 5-year kidney graft survival rates of 48-89% for CLKT and 14-45% for KT. PLT and SLKT yielded 1-year patient and graft survival rates up to 100% in small cohorts.

CONCLUSIONS

Our study suggests that CLKT leads to superior kidney graft survival compared to KT. However, evidence for merits of SLKT or for KT in pyridoxine-responsive patients was scarce, which warrants further studies, ideally using data from a large international registry.

Lumasiran, an RNAi Therapeutic for Primary Hyperoxaluria Type 1

BACKGROUND

Primary hyperoxaluria type 1 (PH1) is a rare genetic disease caused by hepatic overproduction of oxalate that leads to kidney stones, nephrocalcinosis, kidney failure, and systemic oxalosis. Lumasiran, an investigational RNA interference (RNAi) therapeutic agent, reduces hepatic oxalate production by targeting glycolate oxidase.

METHODS

In this double-blind, phase 3 trial, we randomly assigned (in a 2:1 ratio) patients with PH1 who were 6 years of age or older to receive subcutaneous lumasiran or placebo for 6 months (with doses given at baseline and at months 1, 2, 3, and 6). The primary end point was the percent change in 24-hour urinary oxalate excretion from baseline to month 6 (mean percent change across months 3 through 6). Secondary end points included the percent change in the plasma oxalate level from baseline to month 6 (mean percent change across months 3 through 6) and the percentage of patients with 24-hour urinary oxalate excretion no higher than 1.5 times the upper limit of the normal range at month 6.

RESULTS

A total of 39 patients underwent randomization; 26 were assigned to the lumasiran group and 13 to the placebo group. The least-squares mean difference in the change in 24-hour urinary oxalate excretion (lumasiran minus placebo) was -53.5 percentage points (P<0.001), with a reduction in the lumasiran group of 65.4% and an effect seen as early as month 1. The between-group differences for all hierarchically tested secondary end points were significant. The difference in the percent change in the plasma oxalate level (lumasiran minus placebo) was -39.5 percentage points (P<0.001). In the lumasiran group, 84% of patients had 24-hour urinary oxalate excretion no higher than 1.5 times the upper limit of the normal range at month 6, as compared with 0% in the placebo group (P<0.001). Mild, transient injection-site reactions were reported in 38% of lumasiran-treated patients.

CONCLUSIONS

Lumasiran reduced urinary oxalate excretion, the cause of progressive kidney failure in PH1. The majority of patients who received lumasiran had normal or near-normal levels after 6 months of treatment. (Funded by Alnylam Pharmaceuticals; ILLUMINATE-A ClinicalTrials.gov number, NCT03681184.).

Liver Transplantation Outcome in Iranian Patients with Primary Hyperoxaluria; Risks and Perspectives

Background: Primary hyperoxaluria (PH) is an autosomal genetic disorder characterized by abnormal glycosylate metabolism. Objectives: The aim of the present study was to assess post-transplant complications and survival of patients with PH who underwent either liver transplantation (LT) or simultaneous liver-kidney transplantation. Methods: 18 patients with established PH diagnosis who underwent LT or simultaneous liver-kidney transplantation in the Transplantation Center of Shiraz, Iran, were included. Demographic and clinical data were collected by reviewing clinical documents and interviews by the patients. The patients were prospectively followed up for the occurrence of the intended outcomes. The data was analyzed by SPSS 18 software. Results: 12 patients (66.7%) were male, and six patients (33.3%) were female with the age range of 3 to 32 years (mean age, 18.89 ± 7.42 years). The patients’ weight ranged from 13 to 73 kg (mean weight, 47.39 ± 17.18 kg). Polyuria was the most common clinical presentation (11/18), and end-stage renal disease and hemodialysis were noted in 13 and 12 patients pre-transplantation, respectively. Hepatic arterial thrombosis, biliary complications, infections, and graft rejection comprised the most frequent post-transplant complications. Of 18 patients, seven patients (38.9%) died due to various complications during one year after transplant. Based on the Kaplan-Meier analysis, the survival rate was 61.1% at the end of the study. The mean survival time was 46.25 ± 18.6 months. The patients succumbed to the disease died within 3 to 320 days (mean, 61.57 days) post-surgery. Conclusions: LT seems an effective intervention in prevention of kidney failure in patients with PH.

Liver Transplant for Primary Hyperoxaluria Type 1: Results of Sequential, Combined Liver and Kidney, and Preemptive Liver Transplant

OBJECTIVES

Primary hyperoxaluria type 1 is an autosomal recessive disorder that causes overproduction and urinary excretion of oxalate. Liver transplant has been suggested as a treatment for primary hyperoxaluria type 1 since the defective enzyme is expressed in the liver. This study aimed to investigate results of combined liver and kidney, sequential, and preemptive livertransplantin patients with primary hyperoxaluria type 1.

MATERIALS AND METHODS

In this cohort study, we followed patients with primary hyperoxaluria type 1 who underwent liver transplant at our centerin Shiraz, Iran. Clinical and laboratory data of patients were gathered, and major outcomes, including renal failure after liver transplant, rejection, and mortality were recorded. Survival of patients was analyzed by the Kaplan-Meier method.

RESULTS

Our study included 24 patients. There were 16 male (66.6%) and 8 female (33.33%) patients. Thirteen patients were in the pediatric age group (age < 18 y), and 11 patients were adults (age ≥ 18 y). Thirteen patients underwent sequential transplant, 8 patients underwent combined liver and kidney transplant, and 3 patients underwent preemptive transplant. All patients received organs from deceased donors. There were no statistically significant differences in mortality, rejection, and hemodialysis after transplant between those with sequential transplant and those with combined liver and kidney transplant (P > .05).

CONCLUSIONS

Liver transplant can be considered a treatment for patients with primary hyperoxaluria type 1. Combined liver and kidney transplant and preemptive liver transplant could be proper options for these patients.

Bilateral native nephrectomy reduces systemic oxalate level after combined liver-kidney transplant: A case report

Primary hyperoxaluria type 1 (PH1) is a rare liver enzymatic defect that causes overproduction of plasma oxalate. Accumulation of oxalate in the kidney and subsequent renal failure are fatal to PH1 patients often in pediatric age. Combined liver and kidney transplantation is the therapy of choice for end-stage renal disease due to PH1. Levels of plasma oxalate remain elevated for several months after liver transplantation, as the residual body oxalate is slowly excreted. Patients with persistent hyperoxaluria after transplant often require hemodialysis, and accumulation of residual oxalate in the kidney can induce graft dysfunction. As the native kidneys are the main target of calcium oxalate accumulation, we postulated that removal of native kidneys could drastically decrease total body oxalate levels after transplantation. Here, we report a case of bilateral nephrectomy at the time of combined liver-kidney transplantation in a pediatric PH1 patient. Bilateral nephrectomy induced a rapid decrease in plasma oxalate to normal levels in less than 20 days, compared to the several months reported in the literature. Our results suggest that removal of native kidneys could be an effective strategy to decrease the need for hemodialysis and the risk of renal dysfunction after combined liver-kidney transplantation in patients with PH1.

An institutional experience of pre-emptive liver transplantation for pediatric primary hyperoxaluria type 1

Primary hyperoxaluria type 1 (PH1) is an inherited metabolic disease that culminates in ESRF. Pre-emptive liver transplantation (pLTx) treats the metabolic defect and avoids the need for kidney transplantation (KTx). An institutional experience of pediatric PH1 LTx is reported and compared to the literature. Between 2004 and 2015, eight children underwent pLTx for PH1. Three underwent pLTx with a median GFR of 40 (30-46) mL/min/1.73 m(2) and five underwent sequential combined liver-kidney transplantation (cLKTx); all were on RRT at the time of cLKTx. In one case of pLTx, KTx was required eight and a half yr later. pLTx was performed in older (median 8 vs. 2 yr) and larger children (median 27 vs. 7.75 kg) that had a milder PH1 phenotype. In pediatric PH1, pLTx, ideally, should be performed before renal and extrarenal systemic oxalosis complications have occurred, and pLTx can be used "early" or "late." Early is when renal function is preserved with the aim to avoid renal replacement. However, in late (GFR < 30 mL/min/1.73 m(2) ), the aim is to stabilize renal function and delay the need for KTx. Ultimately, transplant strategy depends on PH1 phenotype, disease stage, child size, and organ availability.

Primary hyperoxalurias: diagnosis and treatment

Primary hyperoxalurias (PH) comprise a group of three distinct metabolic diseases caused by derangement of glyoxylate metabolism in the liver. Recent years have seen advances in several aspects of PH research. This paper reviews current knowledge of the genetic and biochemical basis of PH, the specific epidemiology and clinical presentation of each type, and therapeutic approaches in different disease stages. Potential future specific therapies are discussed.

Monogenic diseases that can be cured by liver transplantation

While the prevalence of most diseases caused by single-gene mutations is low and defines them as rare conditions, all together, monogenic diseases account for approximately 10 in every 1000 births according to the World Health Organisation. Orthotopic liver transplantation (LT) could offer a therapeutic option in monogenic diseases in two ways: by substituting for an injured liver or by supplying a tissue that can replace a mutant protein. In this respect, LT may be regarded as the correction of a disease at the level of the dysfunctional protein. Monogenic diseases that involve the liver represent a heterogeneous group of disorders. In conditions associated with predominant liver parenchymal damage (i.e., genetic cholestatic disorders, Wilson's disease, hereditary hemochromatosis, tyrosinemia, α1 antitrypsin deficiency), hepatic complications are the major source of morbidity and LT not only replaces a dysfunctional liver but also corrects the genetic defect and effectively cures the disease. A second group includes liver-based genetic disorders characterised by an architecturally near-normal liver (urea cycle disorders, Crigler-Najjar syndrome, familial amyloid polyneuropathy, primary hyperoxaluria type 1, atypical haemolytic uremic syndrome-1). In these defects, extrahepatic complications are the main source of morbidity and mortality while liver function is relatively preserved. Combined transplantation of other organs may be required, and other surgical techniques, such as domino and auxiliary liver transplantation, have been attempted. In a third group of monogenic diseases, the underlying genetic defect is expressed at a systemic level and liver involvement is just one of the clinical manifestations. In these conditions, LT might only be partially curative since the abnormal phenotype is maintained by extrahepatic synthesis of the toxic metabolites (i.e., methylmalonic acidemia, propionic acidemia). This review focuses on principles of diagnosis, management and LT results in both paediatric and adult populations of selected liver-based monogenic diseases, which represent examples of different transplantation strategies, driven by the understanding of the expression of the underlying genetic defect.

Hyperoxaluria and systemic oxalosis: an update on current therapy and future directions

INTRODUCTION

The primary hyperoxalurias (PH) are rare, but underdiagnosed disorders where the loss of enzymatic activity in key compounds of glyoxylate metabolism results in excessive endogenous oxalate generation. Clinically, they are characterized by recurrent urolithiasis and/or nephrocalcinosis. PH type I is the most frequent and most devastating subtype often leading to early end-stage renal failure.

AREAS COVERED

Profound overview of clinical, diagnostic, and currently available treatment options with a focus on PH I at different stages of the disease. Discussion of future therapeutic avenues including pharmacological chaperones (small molecules rescuing protein function), gene therapy with safer adenoviral vectors, and potential application of cell-based transplantation strategies is provided.

EXPERT OPINION

Due to lack of familiarity with PH and its heterogeneous clinical expression, diagnosis is often delayed until advanced disease is present, a condition, requiring intensive hemodialysis and timely transplantation. Achieving the most beneficial outcome largely depends on the knowledge of the clinical spectrum, early diagnosis, and initiation of treatment before renal failure ensues. A number of preconditions required for substantial improvement in the care of orphan disease like PH have now been achieved or soon will come within reach, so new treatment options can be expected in the near future.

An update on primary hyperoxaluria

The autosomal recessive inherited primary hyperoxalurias types I, II and III are caused by defects in glyoxylate metabolism that lead to the endogenous overproduction of oxalate. Type III primary hyperoxaluria was first described in 2010 and further types are likely to exist. In all forms, urinary excretion of oxalate is strongly elevated (>1 mmol/1.73 m(2) body surface area per day; normal <0.5 mmol/1.73 m(2) body surface area per day), which results in recurrent urolithiasis and/or progressive nephrocalcinosis. All entities can induce kidney damage, which is followed by reduced oxalate elimination and consequent systemic deposition of calcium oxalate crystals. Systemic oxalosis should be prevented, but diagnosis is all too often missed or delayed until end-stage renal disease (ESRD) occurs; this outcome occurs in >30% of patients with primary hyperoxaluria type I. The fact that such a large proportion of patients have such poor outcomes is particularly unfortunate as ESRD can be delayed or even prevented by early intervention. Treatment options for primary hyperoxaluria include alkaline citrate, orthophosphate, or magnesium. In addition, pyridoxine treatment can be used to normalize or reduce oxalate excretion in about 30% of patients with primary hyperoxaluria type I. Time on dialysis should be short to avoid overt systemic oxalosis. Transplantation methods depend on the type of primary hyperoxaluria and on the particular patient, but combined liver and kidney transplantation is the method of choice in patients with primary hyperoxaluria type I and isolated kidney transplantation is the preferred method in those with primary hyperoxaluria type II. To the best of our knowledge, progression to ESRD has not yet been reported in any patient with primary hyperoxaluria type III.

Domino liver transplantation: how far can we push the paradigm?

Domino liver transplantation (DLT) has emerged as a strategy for increasing the number of liver grafts available: morphologically normal livers from donors with metabolic diseases can be used for select recipients with hepatocellular carcinoma (usually outside the Milan criteria). Familial amyloidotic polyneuropathy (FAP) is the most common indication for DLT. When FAP patients are involved in DLT, the indications and outcomes are clear and good, although de novo FAP development within various periods of time has been described in DLT recipients of FAP livers. With the increasing need for organs, livers explanted from patients with rare metabolic diseases, such as primary hyperoxaluria (PH), acute intermittent porphyria (AIP), maple syrup urine disease (MSUD), and homozygous familial hypercholesterolemia (HFHC), are being used for DLT. However, insufficient data about the use of livers from patients with these rare metabolic diseases are available. In this review, we focus on the latter disorders. PH is not a good indication for DLT because recipients of PH livers develop hyperoxaluria and early acute renal failure. AIP also seems to be a debatable indication for DLT because of the rapid development of neurotoxicity in AIP liver recipients. However, the outcomes of DLT with HFHC and MSUD liver grafts (which include the risk of the de novo development of these genetic diseases) are promising. For rare metabolic liver diseases to be established as indications for DLT, more reports and studies are needed.

Excellent renal function and reversal of nephrocalcinosis 8 years after isolated liver transplantation in an infant with primary hyperoxaluria type 1

Primary hyperoxaluria type 1 (PH-1) is a rare autosomal recessive disease caused by the absence or deficiency of the liver-specific intermediary metabolic enzyme alanine glyoxylate aminotransferase. The prognosis of this metabolic disease is poor. Theoretically, the primary metabolic defect can be cured by liver transplantation. However, controversy exists around the age and stage of the disease that liver transplantation should be performed. We report on a patient who presented at the early age of 2 months with nephrocalcinosis. Isolated liver transplantation was performed at the age of 21 months. Eight years later, the estimated glomerular filtration rate was 85 ml/min/1.73 m(2), and imaging studies did not reveal nephrocalcinosis. This case report supports the strategy of early isolated liver transplantation in patients with PH-1.

Pre-emptive liver transplantation for primary hyperoxaluria (PH-I) arrests long-term renal function deterioration

BACKGROUND

Primary hyperoxaluria-I (PH-I) is a serious metabolic disease resulting in end-stage renal disease. Pre-emptive liver transplantation (PLT) for PH-I is an option for children with early diagnosis. There is still little information on its effect on long-term renal function in this situation.

METHODS

Long-term assessment of renal function was conducted using Schwartz's formula (estimated glomerular filtration rate-eGFR) in four children (Group A) undergoing PLT between 2002 and 2008, and a comparison was done with eight gender- and sex-matched controls (Group B) having liver transplantation for other indications.

RESULTS

All patients received a liver graft from a deceased donor. Median follow-up for the two groups was 64 and 94 months, respectively. One child in Group A underwent re-transplantation due to hepatic artery thrombosis, while acute rejection was seen in one. A significant difference was seen in eGFR at transplant (81 vs 148 mL/min/1.73 m(2)) with greater functional impairment seen in the study population. In Group A, renal function reduced by 21 and 11% compared with 37 and 35% in Group B at 12 and 24 months, respectively. At 2 years post-transplantation, there was no significant difference in eGFR between the two groups (72 vs 100 mL/min/1.73 m(2), respectively; P = 0.06).

CONCLUSIONS

Renal function remains relatively stable following pre-emptive LTx for PH-I. With early diagnosis of PH-I, isolated liver transplantation may prevent progression to end-stage renal disease and the need for renal transplantation.

Successful outcome after early combined liver and en bloc-kidney transplant in an infant with primary hyperoxaluria type 1: a case report

PH1 is a metabolic disorder characterized by urolithiasis and the accumulation of oxalate crystals in the kidneys and other organs. Although patients often first present with renal failure, PH1 results from a deficiency of the hepatic peroxisomal enzyme AGT. Ultimately only liver transplantation will cure the underlying metabolic defect. Herein, we report the case of a three-month-old male infant diagnosed with PH and treated using a combined liver and en bloc-kidney transplant from a single donor. At the time of transplant, the patient was 11 months old and weighed 7.9 kg. He received a full size liver graft and en bloc kidneys from a two-yr-old donor. At 36 months post-transplant, the patient is steadily growing with normal renal and hepatic function. This is one of the first reports of successful liver and en bloc-kidney transplantation with abdominal compartment expansion by PTFE for the infantile form of PH1 in a high risk child before one yr of age. Prompt diagnosis and early referral to a specialized center for liver and kidney replacement offer the best chance for survival for infants with this otherwise fatal disease.

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.

Two-step transplantation for primary hyperoxaluria: cadaveric liver followed by living donor related kidney transplantation

In PH, PLTX, although ideal in theory, is rarely achieved. Patients usually have reached end-stage kidney disease while requiring combined liver and kidney transplantation. In this combined procedure, the sudden high oxalates mobilization from blood and tissue stores jeopardizes the success of the kidney graft, with a high risk of post-transplant early kidney necrosis or chronic graft damage. Here, we report the case of a three-yr-old girl with PH and ESRF in whom we performed sequentially deceased donor liver transplantation followed four months later by living donor kidney transplant, after normalization of blood oxalate levels and improvement of urinary oxalate output. After this two-step transplantation, our patient showed normalization of renal function with good urinary output and maintained normal blood oxalate levels. This strategy seems to be a reasonable approach in order to avoid acute renal tubular injury because of oxalate excretion in these patients.

Transplantation procedures in children with primary hyperoxaluria type 1: outcome and longitudinal growth

BACKGROUND

Cure of the metabolic defect in primary hyperoxaluria type 1 (PH1) is possible with liver transplantation (LTx). Preemptive LTx (PLTx) was promoted to prevent chronic kidney disease due to nephrocalcinosis and urolithiasis. However, timing of this procedure is difficult in view of the heterogeneity of PH1 and effective conservative treatment. Combined liver-kidney transplantation (LKTx) is able to cure metabolic defect and replace renal function at the same time and is effective and indicated for patients with or approaching end-stage renal disease (ESRD). Sometimes a sequential approach for LKTx (first liver, then kidney) has been recommended.

METHODS

We report on 13 patients with PH1 since 1995 who underwent transplantation procedures in our center for PH1 at a median age of 4.7 (range 1.4-8.9) years.

RESULTS

The first two patients, planned for a sequential strategy, died early after LTx because of infectious complications. Four patients underwent PLTx at a median glomerular filtration rate of 65 (range 27-98) mL/min/1.73 m/day (Hoppe et al., Pediatr Nephrol 1996; 10: 488), and three patients still have sufficient residual renal function after a follow-up of median 11.6 years. Seven patients with ESRD received a combined LKTx, including four with infantile oxalosis, and three weighing less than 10 kg. There was no mortality and catch-up growth was observed in most patients.

CONCLUSION

In summary and conclusion, transplantation procedures are challenging in PH1, but our results including growth data are encouraging. PLTx remains an option despite the difficulties in timing the procedure. LKTx is indicated for patients with ESRD and is possible even in patients with infantile oxalosis and may improve longitudinal growth.

The primary hyperoxalurias

The primary hyperoxalurias (PHs) are rare disorders of glyoxylate metabolism in which specific hepatic enzyme deficiencies result in overproduction of oxalate. Due to the resulting severe hyperoxaluria, recurrent urolithiasis or progressive nephrocalcinosis are principal manifestations. End stage renal failure frequently occurs and is followed by systemic oxalate deposition along with its devastating effects. Due to the lack of familiarity with PHs and their heterogeneous clinical expressions, the diagnosis is often delayed until there is advanced disease. In recent years, improvements in medical management have been associated with better patient outcomes. Although there are several therapeutic options that can help prevent early kidney failure, the only curative treatment to date is combined liver-kidney transplantation in patients with type I PH. Promising areas of investigation are being identified. Knowledge of the spectrum of disease expression, early diagnosis, and initiation of treatment before renal failure are essential to realize a benefit for patients.

Pediatric liver transplantation for metabolic liver disease: experience at King's College Hospital

AIMS

The aims of this article were to report a single-center experience of pediatric liver transplantation for liver-based metabolic disorders and to compare the outcome of cirrhotic versus noncirrhotic metabolic liver disease.

METHODS

The medical records of 96 patients younger than 18 years undergoing transplantation for liver-based metabolic disorders from 1989 to 2005 were reviewed.

RESULTS

Hundred twelve transplants were performed in 96 patients at a median age of 59.7 months (range, 0-208 months). The cumulative 1-, 5-, and 10-year graft and patient survival rates were 83%, 77%, and 62% and 91%, 86%, and 82%, respectively. Acute liver failure at first presentation (hazard ratio [HR] 3.0; 95% confidence interval [CI] 1.1-8.1), age less than 1 year at time of transplantation (HR 4.6; 95% CI 1.7-12.4) and hospitalization (HR 3.2; 95% CI 1.1-9.3) were significant predictors of worse patient survival. For noncirrhotic disorders, the long-term patient (100% vs. 100%, 90% vs. 100%, and 90% vs. 75%, P=0.87) and graft survivals (93% vs. 100%, 70% vs. 100%, and 70 vs. 75%, P=0.12) at 1, 5, and 7 years for auxiliary versus orthotopic transplantation were not significantly different.

CONCLUSIONS

Long-term patient survival after transplantation for metabolic disorders is excellent for both cirrhotic and noncirrhotic metabolic disorders. For noncirrhotic metabolic disorders, auxiliary transplantation has similar patient and graft survival compared with orthotopic transplantation, but further research is recommended.

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.

The primary hyperoxalurias

The primary hyperoxalurias (PHs) are rare autosomal-recessive inborn errors of metabolism. In the most severe form (type 1), recurrent kidney stones and progressive nephrocalcinosis lead to the loss of kidney function, accompanied by systemic oxalosis, and often requires dialysis and/or transplantation. The variety of genetic mutations leading to PH increasingly are being defined, resulting in the ability to diagnose most patients accurately via minimally invasive means. During and after definitive diagnosis, supportive therapies with pyridoxine supplementation, urinary crystallization inhibitors, and hydration should be used, but have varying success. Emerging information about the renal tubular and intestinal transport of oxalate is leading to increasing evidence to support the use of oxalate-degrading bacteria (probiotics) and enzymes in the treatment of PH. Organ transplantation historically has offered the only potential cure for PH, and may include kidney-alone, combined liver-kidney, or pre-emptive liver-alone transplantation. Exciting new approaches in the treatment of type 1 PH, however, are under investigation. These include the restoration of defective enzymatic activity through the use of chemical chaperones, hepatocyte cell transplantation, or enzyme replacement by recombinant gene therapy. These novel approaches illustrate the goal for the ideal treatment of PH: correcting the genetic defect without exposing patients to the life-long risks associated with organ transplantation.

Metabolic liver disease in children

The aim of this article is to provide essential information for hepatologists, who primarily care for adults, regarding liver-based inborn errors of metabolism with particular reference to those that may be treatable with liver transplantation and to provide adequate references for more in-depth study should one of these disease states be encountered.

Metabolic liver disease in children

The aim of this article is to provide essential information for hepatologists, who primarily care for adults, regarding liver-based inborn errors of metabolism with particular reference to those that may be treatable with liver transplantation and to provide adequate references for more in-depth study should one of these disease states be encountered.

Hyperoxaluria and systemic oxalosis: current therapy and future directions

Excessive urinary oxalate excretion, termed hyperoxaluria, may arise from inherited or acquired diseases. The most severe forms are caused by increased endogenous production of oxalate related to one of several inborn errors of metabolism, termed primary hyperoxaluria. Recurrent kidney stones and progressive medullary nephrocalcinosis lead to the loss of kidney function, requiring dialysis or transplantation, accompanied by systemic oxalate deposition that is termed systemic oxalosis. For most primary hyperoxalurias, accurate diagnosis leads to the use of therapies that include pyridoxine supplementation, urinary crystallisation inhibitors, hydration with enteral fluids and, in the near future, probiotic supplementation or other innovative therapies. These therapies have varying degrees of success, and none represent a cure. Organ transplantation results in reduced patient and organ survival when compared with national statistics. Exciting new approaches under investigation include the restoration of defective enzymatic activity through the use of chemical chaperones and hepatocyte cell transplantation, or recombinant gene therapy for enzyme replacement. Such approaches give hope for a future therapeutic cure for primary hyperoxaluria that includes correction of the underlying genetic defect without exposure to the life-long dangers associated with organ transplantation.

Presentation and role of transplantation in adult patients with type 1 primary hyperoxaluria and the I244T AGXT mutation: Single-center experience

Primary hyperoxaluria type 1 (PH1) is a rare genetic disorder characterized by allelic and clinical heterogeneity. We aim to describe the presentation and full single-center experience of the management of PH1 patients bearing the mutation described in our community (I244T mutation+polymorphism P11L). Since 1983, 12 patients with recurrent renal lithiasis have been diagnosed with PH1 and renal failure in the Canary Islands, Spain. Diagnostic confirmation was based on the presence of oxalosis in undecalcified bone or kidney allograft biopsy, reduced alanine:glyoxylate aminotransferase activity in liver biopsy, and blood DNA analysis. Patients underwent different treatment modalities depending on individual clinical circumstances and therapeutic possibilities at the time of diagnosis: hemodialysis, isolated kidney, simultaneous liver-kidney, or pre-emptive liver transplantation. In all cases, the presentation of advanced renal disease was relatively late (>13 years) and no cases were reported during lactancy or childhood. The eight patients treated with hemodialysis or isolated kidney transplantation showed unfavorable evolution leading to death over a variable period of time. In contrast, the four patients undergoing liver transplantation (three liver+kidney and one pre-emptive liver alone) showed favorable long-term allograft and patient survival (up to 12 years follow-up). In conclusion, in this PH1 population, all bearing the I244T mutation, the development of end-stage renal disease was distinctive during late adolescence or adulthood. Our long-term results support pre-emptive liver transplantation at early stages of renal failure, and kidney-liver transplantation for those with advanced renal disease.

Liver transplantation for non-hepatotoxic inborn errors of metabolism

Hepatic-based inborn errors of metabolism are targets for treatment with liver transplantation in children, in whom the metabolic defect causes irreversible damage to the liver. However, certain metabolic defects originate with enzyme deficiencies localized in the liver but then give rise to toxic intermediates that damage extrahepatic organs without any significant compromise of general liver function. Here, the rationale of using liver transplantation to replace an organ that is functioning normally except for a specific metabolic pathway raises difficult questions about indications for transplantation, timing, amount of replacement tissue needed to correct the defect, and whether heterozygote parents are suitable living donors for liver transplantation in their affected children. This review explores these questions and others, including the role of hepatocyte transplantation, in this select group of disorders. Until the promise of specific gene or enzyme replacement therapy is realized, liver and hepatocyte transplantation offers the best chance of achieving metabolic control in these challenging patients.

The role of preemptive liver transplantation in primary hyperoxaluria type 1

In primary hyperoxaluria the deficiency or mistargeting of hepatic alanine-glyoxylate aminotransferase (AGT) leads to the overproduction of oxalate resulting in hyperoxaluria and renal damage due to urolithiasis and/or nephrocalcinosis. Presently, the cure of the metabolic defect can be achieved only by liver transplantation. While for patients with end-stage renal disease combined hepatorenal transplantation is recommended, the concept of preemptive liver transplantation (PLTX), i.e. cure of the metabolic defect before renal damage occurs, has received considerable attention. Due to the heterogenous clinical course in PH1, optimal timing of PLTX is a matter of debate. Advocators of PLTX would consider a patient with a slowly declining GFR, reaching levels of 40-60 ml/min/1.73 m(2), as an ideal candidate, while others would continue medical treatment in these patients and opt for rapid combined liver-kidney transplantation if GFR reaches even lower levels. This review will discuss the background and rationale of PLTX and gives an update on 11 patients with PLTX who have been reported in the literature to date.

Renal function following liver transplantation in children

The literature regarding the etiology and incidence of short and long-term renal functional impairment in pediatric liver allograft recipients was reviewed. Most of the reports include recipients receiving cyclosporine as the primary immunosuppressant. Using calculated glomerular filtration rate (cGFR), creatinine clearance or the serum creatinine level will lead to an overestimation of GFR. In contrast to data in adults, there are a limited number of pediatric recipients whose renal dysfunction has progressed to chronic kidney disease or end-state renal disease. Calcineurin inhibitors minimization has proven effective in reversing or preventing progressive deterioration of GFR; however, rejection episodes and complications have limited efficacy of this approach. Future multicenter studies using optimal GFR measurements are required to delineate the magnitude of renal dysfunction in pediatric recipients.

A 20-year experience of combined liver/kidney transplantation for primary hyperoxaluria (PH1): the European PH1 transplant registry experience 1984-2004

Primary hyperoxaluria (PH1) is a condition caused by a hepatic-based enzyme defect which can lead to renal failure due to oxalate stone disease, obstructive uropathy and nephrocalcinosis. It has been shown that the underlying metabolic defect can be corrected by liver transplantation and in most cases (renal failure having already occurred) is accompanied by a kidney graft. This paper describes the current results of 127 liver transplants performed in 117 patients over a 20-year period from 1984 to 2004 in 35 European centres. The mean age at onset of symptoms was 5.6 +/- 7.8 years and the mean age at which a diagnosis was made was 8.8 +/- 9.5 years. The diagnosis was confirmed by liver biopsy proven decreased AGT activity in 68% of cases, hyperoxaluria in 74%, hyperglycolicaciduria in 37% and hyperoxalaemia in 50%. Patients were transplanted at a mean age of 16.5 +/- 11.4 years following a period of dialysis of 3.2 +/- 3.2 years (range 0-14.4 years). 1-, 5- and 10-year patient survival values were 86, 80 and 69%, respectively, and liver graft survival rates of 80, 72 and 60% at the same time intervals. There have been 27 deaths and 10 liver retransplants have been carried out. Patient outcomes are improved when prolonged periods on dialysis and the complications of systemic oxalosis have not occurred.

Intra-familial clinical heterogeneity: absence of genotype-phenotype correlation in primary hyperoxaluria type 1 in Israel

BACKGROUND/AIMS

Primary hyperoxaluria type 1 (PH1) is caused by the deficiency of the liver enzyme alanine:glyoxylate aminotransferase which results in increased synthesis and excretion of oxalate. The clinical manifestations of PH1 are heterogeneous with respect to the age of onset and rate of progression. The aim of this study was to investigate possible relationships between a given genotype, the biochemical profile and the clinical phenotype.

METHODS

We conducted a study of 56 patients from 22 families with PH1 from Israel. The clinical and biochemical data were compiled and the genotype was determined for each family.

RESULTS

The prevalent phenotype was of early onset with progression to end-stage renal disease during the first decade of life. Fifteen PH1-causing mutations were detected in 21 families: 10 were first described in this patient population. Marked intra-familial clinical heterogeneity was noted, meaning that there was no correlation between a given genotype and the phenotype.

CONCLUSIONS

The clinical course of patients with PH1 is not dictated primarily by its genotype. Other genetic and/or environmental factors play a role in determining the ultimate phenotype.

A United States survey on diagnosis, treatment, and outcome of primary hyperoxaluria

Primary hyperoxaluria (PH) is a heterogeneous disease with a variable age of onset and a variable progression into kidney failure. Early diagnosis is mandatory to avoid the damaging effects of systemic calcium oxalate deposition. In 1997, we initiated a nationwide survey of American nephrologists to ascertain epidemiological data and current practices. PH was reported in only 102 patients, with PH I in 79 and PH II in 9; 14 patients were not classified. Most patients were Caucasian (84%). Main symptoms at diagnosis were urolithiasis (54.4%) and nephrocalcinosis (30%). A significant delay of diagnosis was seen in 42% of patients and 30% of patients were diagnosed only at end-stage renal disease (ESRD). Diagnosis was usually based on history and urinary oxalate excretion. Glycolate and l-glyceric acid excretion were rarely determined. To determine the enzyme defect, a liver biopsy was performed in 40%. Even at ESRD, only 56% of patients received an adequate diagnostic work-up. Half of the patients showed 'good' or 'fair' pyridoxine sensitivity. In addition to B(6), most patients received either citrate or orthophosphate. Kidney transplantation (KTx) failed in 19 of 32 transplants ( n=27 patients) and was due to recurrent oxalosis in 8 transplants. Liver Tx was performed after KTx in 5 patients (1 patient died). Combined liver-kidney Tx in 21 patients (in 9 patients after failure of KTx) achieved good organ function in 13 patients; 7 patients, however, died shortly after transplantation. In conclusion, the time between first symptom and diagnosis of PH must be minimized, and the diagnostic procedures have to be improved. The cases of unclassified hyperoxaluria suggest the possibility of additional type(s) of PH. As isolated KTx failed in 59% of patients, combined liver-kidney Tx seems to be the better choice in place of isolated KTx as the primary transplant procedure.

Results of combined and sequential liver-kidney transplantation

Experience with combined liver-kidney transplantation (L-KTx) has increased, but controversy regarding this procedure continues because the indications are not clearly defined yet. Between 1984 and 2000, 38 patients underwent simultaneous L-KTx and 9 patients underwent sequential transplantation, receiving either a liver before a kidney or a kidney before a liver. Main indications for a simultaneous procedure were polycystic liver-kidney disease with cirrhosis and coincidental renal failure. The main indications for sequential procedure were cirrhosis caused by viral infection for the liver and glomerulonephritis for the kidneys. Outcomes in these patients were evaluated retrospectively. Regarding simultaneous transplantation, 28 (73.7%) long-term survivors were followed up for 0.7 to 12.5 years. Currently, 24 (63.2%) patients are alive with good liver function. Fourteen patients died; 10 patients died in the early postoperative phase because of septic complications, and most of them were cirrhotic with a poor preoperative clinical status. Currently, 2 of the surviving patients (8%) have returned to dialysis, 4 (17%) have reduced renal function, and 18 (75%) have good renal function. Five liver and 2 kidney retransplantations were performed during the follow-up. In cases of sequential grafting, patients undergoing kidney transplantation in the presence of a previously transplanted stable liver did better than those who underwent liver transplantation after kidney transplantation. When liver transplantation was performed early and electively before substantial worsening, combined L-KTx is a safe procedure offering excellent long-term palliation.

Liver transplantation in the UK

INTRODUCTION

This paper provides a review of the practice of liver transplantation with the main emphasis on UK practice and indications for transplantation.

REFERRAL AND ASSESSMENT

This section reviews the process of referral and assessment of patients with liver disease with reference to UK practice.

DONOR ORGANS

The practice of brainstem death and cadaveric organ donation is peculiar to individual countries and rates of donation and potential areas of improvement are addressed.

OPERATIVE TECHNIQUE

The technical innovations that have led to liver transplantation becoming a semi-elective procedure are reviewed. Specific emphasis is made to the role of liver reduction and splitting and living related liver transplantation and how this impacts on UK practice are reviewed. The complications of liver transplan-tation are also reviewed with reference to our own unit. Immunosuppression:The evolution of immunosuppression and its impact on liver transplantation are reviewed with some reference to future protocols.

RETRANSPLANTATION

The role of retransplantation is reviewed.

OUTCOME AND SURVIVAL

The results of liver transplantation are reviewed with specific emphasis on our own experience.

FUTURE

The future of liver transplantation is addressed.

Domino as a bridge to definitive liver transplantation in a neonate

An interim liver transplant was used to extend survival in a neonate. This was accomplished by the initial transplant of a left-lateral segment of a metabolically abnormal liver obtained from a 7-yr-old patient with primary oxalosis. This bridging strategy was required because our neonatal patient was dying of fulminant hepatic failure caused by hepatic vein thrombosis and a small liver or liver segment could not be found. Although problems with hyperoxaluria were encountered in the neonate post-transplant, the interim liver transplant enabled the baby to survive and grow until the age of 4 months. At that time, a definitive transplant was performed using the left-lateral segment of his mother's liver. This case represents the first reported use of a pediatric domino transplant where a metabolically abnormal liver was used to allow sufficient growth to permit a definitive liver transplantation.

Recent advances in pediatric liver transplantation

Pediatric liver transplantation has matured into a well-established, highly successful treatment for advanced pediatric liver disease. Recent 1-year success rates range from 85% to 95%. This unprecedented achievement is the result of careful selection criteria and optimal timing of transplantation, technical advances in surgical technique, and improved treatment following transplant. This report highlights many recent published findings representing advances that have led to current successful approaches.

Pediatric liver transplantation in metabolic disease: clinical decision making

Proper utilization of liver transplantation in the management of pediatric metabolic diseases requires a comprehensive understanding of both metabolic disease and the risk and benefits of transplantation. This brief review focuses on issues that pertain to the treatment of tyrosinemia type I, bile acid biosynthesis disorders, primary hyperoxaluria, Crigler-Najjar Type I, and mitochondrial diseases. These entities are used as prototypes to illustrate many of the principles that are applied in a more general sense to the management of metabolic diseases. The natural history of these disorders are considered in the context of the risks of liver transplantation. Indications, contraindications, and both current and future alternatives to transplantation, are considered.

Auxiliary partial orthotopic liver transplantation from living donors

Auxiliary liver transplantation was originally started in Western countries in the form of heterotopic auxiliary liver transplantation for end-stage liver disease. It thereafter developed into the form of auxiliary partial orthotopic liver transplantation for acute liver failure. In Japan, where living-donor liver transplantation is the main mode of liver transplantation, auxiliary partial orthotopic liver transplantation was initially used for patients with metabolic liver diseases and has since developed into an effective solution for small-for-size living donor grafts. Although there has been a reported case of successful auxiliary partial orthotopic liver transplantation from a living donor for the treatment of acute liver failure, wide application of this technique is made difficult at present by such unsolved problems as functional competition, small graft size, severe clinical status, and toxic liver syndrome. Auxiliary partial orthotopic liver transplantation from a living donor is an established procedure for small-for-size living-donor grafts and metabolic liver diseases, and the future establishment of its successful application to cases of acute liver failure is anticipated.

Liver transplantation in the UK

INTRODUCTION

This paper provides a review of the practice of liver transplantation with the main emphasis on UK practice and indications for transplantation.

REFERRAL AND ASSESSMENT

This section reviews the process of referral and assessment of patients with liver disease with reference to UK practice.

DONOR ORGANS

The practice of brainstem death and cadaveric organ donation is peculiar to individual countries and rates of donation and potential areas of improvement are addressed.

OPERATIVE TECHNIQUE

The technical innovations that have led to liver transplantation becoming a semi-elective procedure are reviewed. Specific emphasis is made to the role of liver reduction and splitting and living related liver transplantation and how this impacts on UK practice are reviewed. The complications of liver transplan-tation are also reviewed with reference to our own unit. Immunosuppression:The evolution of immunosuppression and its impact on liver transplantation are reviewed with some reference to future protocols.

RETRANSPLANTATION

The role of retransplantation is reviewed.

OUTCOME AND SURVIVAL

The results of liver transplantation are reviewed with specific emphasis on our own experience.

FUTURE

The future of liver transplantation is addressed.