Liver transplantation for alpha-1-antitrypsin deficiency in children

Lung and liver transplantation in patients with alpha-1 antitrypsin deficiency

Alpha-1 antitrypsin (AAT) augmentation is effective in slowing the progression of emphysema due to AAT deficiency (AATD) but cannot prevent eventual progression to end-stage lung disease and complete respiratory failure, which is the leading cause of death for individuals with severe AATD. When patients develop end-stage lung disease, lung transplantation is the only treatment option available, and this can improve lung physiology and patient health status. The available data suggest that survival rates for lung transplantation are significantly higher for patients with AATD-related chronic obstructive pulmonary disease (COPD) compared with non-AATD-related COPD, but, conversely, there is a higher risk of common post-lung transplant complications in patients with AATD versus non-AATD COPD. Nevertheless, lung transplantation (single and bilateral) is favorable for patients with AATD. After respiratory failure, the second leading cause of death in patients with AATD is liver disease, for example, cirrhosis and hepatocellular carcinoma, caused by the accumulation of mutant forms of AAT retained within the liver. As with lung disease, the only treatment option for end-stage liver disease is liver transplantation. Survival rates for patients with AATD undergoing liver transplantation are also favorable, and patients, particularly pediatric patients, have benefitted from advancements in peri-/post-surgical care. As the majority of AAT is produced by the liver, the AAT phenotype of the recipient becomes that of the donor, meaning that AAT serum levels should be normalized (if the donor is AAT-replete), halting further lung and liver disease progression. However, post-liver transplant respiratory function may continue to decline in line with normal age-related lung function decline. In the most severe cases, where patients have simultaneous end-stage lung and liver disease, combined lung and liver transplantation is a treatment option with favorable outcomes. However, there is very little information available on this procedure in patients with AATD.

Alpha1-Antitrypsin Deficiency: Transition of Care for the Child With AAT Deficiency into Adulthood

IMPORTANCE

Alpha1-antitrypsin (AAT) deficiency is a common, but an underdiagnosed genetic condition, affecting 1 in 1500 individuals. It can present insidiously with liver disease in children. Although clinical practice guidelines exist for the management of AAT deficiency, especially with regards to pulmonary involvement, there are no published recommendations that specifically relate to the management of the liver disease and monitoring for lung disease associated with this condition, particularly in children.

OBJECTIVE

To review the literature on the management of AAT deficiency-associated liver disease in adults and children.

EVIDENCE REVIEW

A systematic search for articles indexed in PubMed and published was undertaken. Some earlier selected landmark references were included in the review. Search terms included: "alpha1-antitrypsin deficiency"; "liver disease"; "end-stage liver disease"; "liver transplantation" and "preventative management". Recommendations for the management of children with suspected or confirmed AAT deficiency were made according to the Strength of Recommendation Taxonomy scale.

FINDINGS

Liver complications arising from AAT deficiency result from the accumulation of mutated AAT protein within hepatocytes. Liver disease occurs in 10% of children, manifested by cholestasis, pruritus, poor feeding, hepatomegaly, and splenomegaly, but the presentation is highly variable. A diagnostic test for AAT deficiency is recommended for these children. Baseline liver function tests should be obtained to assess for liver involvement; however, the only curative treatment for AAT deficiency-associated liver disease is organ transplantation. Conclusion and Relevance: There should be a greater vigilance for AAT deficiency testing among pediatricians. Diagnosis should prompt assessment of liver involvement. Children with AATdeficiency- associated liver disease should be referred to a liver specialist and monitored throughout their lifetimes for the symptoms of AAT-deficiency-related pulmonary involvement.

Systematic review: the natural history of alpha-1 antitrypsin deficiency, and associated liver disease

BACKGROUND

Alpha-1 antitrypsin deficiency (AATD) is estimated to affect three million people worldwide. It causes liver disease in a proportion of carriers of the PiS and PiZ allele due to the formation and retention of polymers within the endoplasmic reticulum of hepatocytes. The reason for this selective penetrance is not known. Although clinical trials are underway, liver transplantation is the only effective treatment for liver disease due to AATD.

AIMS

To report the prevalence and natural history of liver disease among individuals with AATD, and assess the outcomes of liver transplantation through systematic review.

METHODS

A comprehensive search was conducted across multiple databases. Two independent authors selected the articles and assessed bias using the Newcastle-Ottawa Scale. Data were pooled for analysis, where comparable outcomes were reported.

RESULTS

Thirty-five studies were identified related to disease progression and 12 for the treatment of AATD. Seven per cent of children were reported to develop liver cirrhosis, with 16.5% of individuals presenting in childhood requiring liver transplantation. Of those surviving to adulthood, 10.5% had liver cirrhosis and 14.7% required transplantation. Liver transplantation was the only effective treatment reported and outcomes compare favourably to other indications, with 5-year survival reported as over 90% in children and over 80% in adults.

DISCUSSION

The clinical course of liver disease in individuals with AATD remains poorly understood, but affects about 10% of those with AATD. More research is required to identify those patients at risk of developing liver disease at an early stage, and to provide alternative treatments to liver transplantation.

Liver Transplantation in Alpha-1 Antitrypsin Deficiency

Alpha-1 antitrypsin (AAT) deficiency is a common inherited metabolic disorder caused by a point mutation in the SERPIN1A gene. A small portion of homozygous PI*ZZ individuals develop severe liver disease that requires liver transplantation. Posttransplant survival is excellent. The largest burden of advanced liver disease lies within the adult population rather than children. Evaluation of lung function in adults before transplant is essential because of the underlying risk for chronic obstructive pulmonary disease. Post-liver transplantation lung function should also be monitored for decline. Although uncommon, cases of simultaneous lung and liver transplant for AAT deficiency have been reported.

[Hepatic involvement in hereditary alpha-1-antitrypsin deficiency]

Apha-1-antitrypsin deficiency is an autosomal recessive genetic disorder seen in all races. The molecular defect is a specific mutation of the SERPINA1 gene leading to synthesis of an abnormal protein (alpha-1-antitrypsin Z) that cannot be secreted and polymerizes in the endoplasmic reticulum of hepatocytes. The inter-individual variability in the responses to intracellular stress induced by the accumulation of abnormal polymers and the mechanisms allowing their degradation is, without doubt, responsible for the different clinical manifestations of the disease. The disease affects the liver where the abnormal protein is synthesized and the lung, which is its place of action. Liver involvement is well recognized in homozygous infants of the phenotype ZZ. In this situation the disease may present a varying picture from neonatal cholestasis (about 15% of neonatal defects) to cirrhosis. However, evolution towards cirrhosis affects less than 3% of infants with the ZZ phenotype and it is preceded in 80% of cases by neonatal cholestasis. In adolescents or adults the manifestations associated with alpha-1-antitrypsin deficiency are usually limited to biochemical abnormalities but may lead to cirrhosis or hepatocellular carcinoma. The hepatic disorder and its complications are treated symptomatically though the pulmonary involvement may benefit from substitution treatment. More specific treatments targeting the molecular and cellular abnormalities are the subject of research.

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.

Diagnosis and management of patients with α1-antitrypsin (A1AT) deficiency

Alpha(1)-antitrypsin (A1AT) deficiency is an autosomal codominant disease that can cause chronic liver disease, cirrhosis, and hepatocellular carcinoma in children and adults and increases risk for emphysema in adults. The development of symptomatic disease varies; some patients have life-threatening symptoms in childhood, whereas others remain asymptomatic and healthy into old age. As a result of this variability, patients present across multiple disciplines, including pediatrics, adult medicine, hepatology, genetics, and pulmonology. This can give physicians the mistaken impression that the condition is less common than it actually is and can lead to fragmented care that omits critical interventions commonly performed by other specialists. We sought to present a rational approach for hepatologists to manage adult patients with A1AT deficiency.

Paediatric liver transplantation for metabolic disorders. Part 2: Metabolic disorders with liver lesions

Liver based metabolic disorders account for 10 to 15% of the indications for paediatric liver transplantation. In the last three decades, important progress has been made in the understanding of these diseases, and new therapies have emerged. Concomitantly, medical and surgical innovations have lead to improved results of paediatric liver transplantation, patient survival nowadays exceeding 80% 10 year after surgery with close to normal quality of life in most survivors. This review is a practical update on medical therapy, indications and results of liver transplantation, and potential future therapies, for the main liver based metabolic disorders in which paediatric liver transplantation may be considered. Part 1 focuses on metabolic based liver disorders without liver lesions, and part 2 on metabolic liver diseases with liver lesions.

Pulmonary diseases and the liver

Chronic liver disease is associated with many pulmonary complications. Several, including hepatopulmonary syndrome, portopulmonary hypertension, and hepatic hydrothorax have been extensively reviewed. However, hepatobiliary manifestations of primary pulmonary diseases have received less attention. This review focuses on hepatobiliary complications of respiratory failure, cystic fibrosis, α-1 antitrypsin deficiency, sarcoidosis, and tuberculosis.

Liver transplantation in children with metabolic diseases: the studies of pediatric liver transplantation experience

Metabolic diseases are the second largest indication for LT in children after BA. There are limited data on the long-term post-transplant outcome in this unique group of patients. Therefore, our aim was to assess post-liver transplant outcomes and to evaluate risk factors for mortality and graft loss in children with metabolic disorders in comparison to those with non-metabolic diagnoses. We reviewed all patients enrolled in the SPLIT registry. Between 1995 and 2008, 446 of 2997 (14.9%) children enrolled in SPLIT underwent liver transplant for metabolic diseases. One-yr and five-yr patient survival for children with metabolic diseases was 94.6% and 88.9% and for those with other diseases 90.7% and 86.1% (log-rank p = 0.05), respectively. One-yr and five-yr graft survival for children with metabolic disorders was 90.8% and 83.8%, and for those with other diseases 85.4% and 78.0% (log-rank p = 0.005), respectively. Children with metabolic diseases were less likely to experience gastrointestinal complications (5.6% vs. 10.7%, p = 0.001), portal vein thrombosis (2.9% vs. 5.2%, p = 0.04), and reoperations within 30 days post-transplant (33.4% vs. 37.8%, p = 0.05) than those with other indications. In conclusion, children who underwent liver transplant for metabolic disease had similarly excellent patient survival as, and better graft survival than, those who received a liver allograft for other indications.

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.

Liver disease in alpha 1-antitrypsin deficiency: a review

Alpha 1-antitrypsin deficiency is an inherited metabolic disorder that predisposes the affected individual to chronic pulmonary disease, in addition to chronic liver disease, cirrhosis, and hepatocellular carcinoma. Just over one-third of genetically susceptible adult patients with the most severe phenotype, PiZZ, develop clinically significant liver injury. The clinical presentation of liver disease is variable, and the genetic and environmental factors that predispose some individuals to liver disease while sparing others are unknown. The mechanisms of liver and lung disease are distinct and unique. This article reviews the liver disease associated with alpha 1-antitrypsin deficiency, emphasizing the genetic defect, molecular pathogenesis, natural history, and promising therapies.

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.

Paediatric liver transplantation--a review based on 20 years of personal experience

The natural history of most liver diseases requiring liver replacement in children is well known, and the potential of this therapy has been ascertained regarding life expectancy, which currently exceeds 90% in the long term. The timing of liver transplantation must be anticipated, to reduce the physical, psychological and mental impact of chronic liver diseases. Several studies show evidence that the best long-term results with regard to patient and graft survival are obtained with grafts procured from relatively young donors. Since the shortage of post-mortem liver donors will most likely worsen, further development of live, related-donor transplantation can be expected. The main progress to come will concern immunosuppression, taking advantage of the immunological privilege of the liver. Protocols are under development for induction of operational tolerance.

Analyses of hepatocellular proliferation in a mouse model of alpha-1-antitrypsin deficiency

alpha-1-Antitrypsin (alpha1-AT) deficiency is the most common cause of metabolic pediatric liver disease. Hepatocellular injury is caused by toxicity of the mutant alpha-1-antitrypsin Z (alpha1-ATZ) molecule retained within hepatocytes. In these studies, we used the PiZ transgenic mouse model of alpha1-AT deficiency to examine hepatocellular proliferation in response to chronic liver injury resulting from this metabolic disease. The results showed increased hepatocellular proliferation and caspase 9 activation in male PiZ mice compared with female PiZ and wild-type mice. Hepatic alpha1-AT mRNA and protein expression also were increased in male PiZ mice, suggesting that greater hepatocellular proliferation and caspase activation in males results from increased hepatotoxicity associated with greater intracellular alpha1-ATZ accumulation. Testosterone treatment of female PiZ mice increased alpha1-ATZ expression and hepatocellular proliferation to a level comparable with that in males. In PiZ mice, hepatocytes devoid of intracellular alpha1-AT globules had a proliferative advantage compared with globule-containing hepatocytes. However, this advantage is relative because both globule-containing and globule-devoid hepatocytes exhibited comparable proliferation after partial hepatectomy. In conclusion, these data indicate that intracellular retention of mutant alpha1-ATZ is associated with a regenerative stimulus leading to increased hepatocellular proliferation, that gender-specific signals influence the degree of alpha1-AT expression and associated hepatic injury, and that hepatocytes devoid of alpha1-ATZ have a proliferative advantage over cells that accumulate the mutant protein. This selective proliferation suggests that hepatocellular transplantation may be applicable for treatment of this and other slowly progressive metabolic liver diseases.

Neonatal hepatitis syndrome

Conjugated hyperbilirubinaemia in an infant indicates neonatal liver disease. This neonatal hepatitis syndrome has numerous possible causes, classified as infective, anatomic/structural, metabolic, genetic, neoplastic, vascular, toxic, immune and idiopathic. Any infant who is jaundiced at 2-4 weeks old needs to have the serum conjugated bilirubin measured, even if he/she looks otherwise well. If conjugated hyperbilirubinaemia is present, a methodical and comprehensive diagnostic investigation should be performed. Early diagnosis is critical for the best outcome. In particular, palliative surgery for extrahepatic biliary atresia has the best chance of success if performed before the infant is 8 weeks old. Definitive treatments available for many causes of neonatal hepatitis syndrome should be started as soon as possible. Alternatively, liver transplantation may be life saving. Supportive care, especially with attention to nutritional needs, is important for all infants with neonatal hepatitis syndrome.

Metabolic liver disease

The discovery of novel metabolic pathways and the genetic basis for diseases of the liver continues to yield new insights into the pathogenesis of inherited metabolic diseases of the liver, whereas the application of new technologies to their treatment continues to advance therapeutic options. This review of selected articles covers a wide range of subjects, from the identification of novel proteins and transport pathways to disease diagnosis and treatment of acute liver failure. Four selected topics, Wilson disease, hemochromatosis and iron overload disorders, alpha-1 antitrypsin disease, and exciting new therapeutic options for lysosomal storage diseases are the focus of this review.