Prevalence and Risk Factors for Liver Involvement in Individuals with PiZZ-related Lung Disease

Liver disease progression in patients with alpha-1 antitrypsin deficiency and protease inhibitor ZZ genotype with or without lung disease

BACKGROUND

Alpha-1 antitrypsin deficiency (AATD) is caused by mutations in SERPINA1, which encodes alpha-1 antitrypsin, a protease inhibitor (Pi). Individuals with AATD and the homozygous Pi*ZZ genotype have variable risk of progressive liver disease but the influence of comorbid lung disease is poorly understood.

AIMS

To characterise patients with AATD Pi*ZZ and liver disease (AATD-LD-Pi*ZZ) with or without lung disease and describe liver disease-related clinical events longitudinally.

METHODS

This was an observational cohort study of patients in the Mayo Clinic Healthcare System (January 2000-September 2021). Patients were identified using diagnosis codes and natural language processing. Fibrosis stage (F0-F4) was assessed using a hierarchical approach at baseline (90 days before or after the index date) and follow-up. Clinical events associated with liver disease progression were assessed.

RESULTS

AATD-LD-Pi*ZZ patients with lung disease had a longer median time from AATD diagnosis to liver disease diagnosis versus those without lung disease (2.2 vs. 0.2 years, respectively). Compared to those without lung disease, patients with lung disease had a longer time to liver disease-related clinical events (8.5 years and not reached, respectively). AATD-LD-Pi*ZZ patients without lung disease were more likely to undergo liver transplantation compared with those with lung disease.

CONCLUSION

In patients with AATD and lung disease, there is a delay in the diagnosis of comorbid liver disease. Our findings suggest that liver disease may progress more rapidly in patients without comorbid lung disease.

Alpha1-antitrypsin deficiency: An updated review

Alpha1-antitrypsin deficiency (AATD) is a rare autosomal recessive disease associated with the homozygous Z variant of the SERPINA1 gene. Clinical expression of AATD, reported 60 years ago associate a severe deficiency, pulmonary emphysema and/or liver fibrosis. Pulmonary emphysema is due to the severe alpha1-antitrypsin deficiency of the ZZ homozygous status and is favored by smoking. Liver fibrosis is due to the ZZ homozygous status and is favored by obesity and excessive chronic alcohol intake, with a risk of liver cancer. Diagnosis is based on serum level and either isoelectric focusing determination of the biochemical phenotype or PCR detection of some variants. SERPINA1 gene sequencing is necessary in case of discrepancies between the results of these tests. No treatment is available for the liver disease in AATD. Although no specific trial has been performed, COPD in AATD should be treated as per COPD recommendations. Based on a randomized clinical trial, augmentation therapy is indicated in non-smoking adults less than 70 years of age with emphysema at chest CT, confirmed homozygous AATD, and FEV1 between 35% and 70% of predicted. In contrast Z heterozygosis (MZ or SZ) brings a risk of lung or liver disease only in association with further risk factors. Early detection, in all patients with COPD and chronic liver disease, is critical for the correct information of Z variant carriers. News ways of correcting the liver production of alpha1-antitrypsin will modify the care of AATD patients.

Wilson Disease and Alpha1-Antitrypsin Deficiency: A Review of Non-Invasive Diagnostic Tests

Wilson disease and alpha1-antitrypsin deficiency are two rare genetic diseases that may impact predominantly the liver and/or the brain, and the liver and/or the lung, respectively. The early diagnosis of these diseases is important in order to initiate a specific treatment, when available, ideally before irreversible organ damage, but also to initiate family screening. This review focuses on the non-invasive diagnostic tests available for clinicians in both diseases. These tests are crucial at diagnosis to reduce the potential diagnostic delay and assess organ involvement. They also play a pivotal role during follow-up to monitor disease progression and evaluate treatment efficacy of current or emerging therapies.

[Alpha 1-antitrypsin deficiency]

INTRODUCTION

Pulmonary emphysema and liver disease are the clinical expressions of alpha 1-antitrypsin deficiency, an autosomal recessive genetic disease.

STATE OF THE ART

Alpha 1-antitrypsin deficiency is usually associated with the homozygous Z variant of the SERPINA1 gene. Its clinical expression always consists in a substantial reduction of alpha 1-antitrypsin serum concentration and its variants are analyzed by isoelectric focalization or molecular techniques. Assessed by CO transfer alteration and CT scan, risk of pulmonary emphysema is increased by tobacco consumption. Assessed by transient elastography and liver ultrasound, risk of liver disease is increased by alcohol consumption or obesity. Treatment of COPD-associated alpha 1-antitrypsin deficiency does not differ from that of other forms of COPD. In patients presenting with severe deficiency, augmentation therapy with plasma-derived alpha 1-antitrypsin reduces the progression of emphysema, as shown in terms of CT-based lung density metrics. Patients with alpha 1-antitrypsin deficiency with a ZZ genotype should refrain from alcohol or tobacco consumption, and watch their weight; so should their close relatives.

PERSPECTIVES

Modulation of alpha 1-antitrypsin liver production offers an interesting new therapeutic perspective.

CONCLUSION

Homozygous (Z) variants of the SERPINA1 gene confer an increased risk of pulmonary emphysema and liver disease, particularly among smokers, drinkers and obese persons.

Diagnosis and management of secondary causes of steatohepatitis

The term non-alcoholic fatty liver disease (NAFLD) was originally coined to describe hepatic fat deposition as part of the metabolic syndrome. However, a variety of rare hereditary liver and metabolic diseases, intestinal diseases, endocrine disorders and drugs may underlie, mimic, or aggravate NAFLD. In contrast to primary NAFLD, therapeutic interventions are available for many secondary causes of NAFLD. Accordingly, secondary causes of fatty liver disease should be considered during the diagnostic workup of patients with fatty liver disease, and treatment of the underlying disease should be started to halt disease progression. Common genetic variants in several genes involved in lipid handling and metabolism modulate the risk of progression from steatosis to fibrosis, cirrhosis and hepatocellular carcinoma development in NAFLD, alcohol-related liver disease and viral hepatitis. Hence, we speculate that genotyping of common risk variants for liver disease progression may be equally useful to gauge the likelihood of developing advanced liver disease in patients with secondary fatty liver disease.

Utility of Transient Elastography for the Screening of Liver Disease in Patients with Alpha1-Antitrypsin Deficiency

Screening of liver disease in alpha-1 antitrypsin deficiency (AATD) is usually carried out with liver enzymes, with low sensitivity. We conducted a multicenter cross-sectional study aiming to describe the utility of transient elastography for the identification of liver disease in patients with AATD. A total of 148 AATD patients were included. Among these, 54.7% were Pi*ZZ and 45.3% were heterozygous for the Z allele. Between 4.9% and 16.5% of patients had abnormal liver enzymes, without differences among genotypes. Liver stiffness measurement (LSM) was significantly higher in Pi*ZZ individuals than in heterozygous Z (5.6 vs. 4.6 kPa; p = 0.001). In total, in 8 (5%) individuals LSM was >7.5 kPa, considered significant liver fibrosis, and ≥10 kPa in 3 (1.9%) all being Pi*ZZ. Elevated liver enzymes were more frequently observed in patients with LSM > 7.5 kPa, but in 5 out of 8 of these patients all liver enzymes were within normal range. In patients with AATD, the presence of abnormal liver enzymes is frequent; however, most of these patients do not present significant liver fibrosis. Transient elastography can help to identify patients with liver fibrosis even with normal liver enzymes and should be performed in all Z-allele carriers to screen for liver disease.

Development of an RNAi therapeutic for alpha-1-antitrypsin liver disease

The autosomal codominant genetic disorder alpha-1 antitrypsin (AAT) deficiency (AATD) causes pulmonary and liver disease. Individuals homozygous for the mutant Z allele accumulate polymers of Z-AAT protein in hepatocytes, where AAT is primarily produced. This accumulation causes endoplasmic reticulum (ER) stress, oxidative stress, damage to mitochondria, and inflammation, leading to fibrosis, cirrhosis, and hepatocellular carcinoma. The magnitude of AAT reduction and duration of response from first-generation intravenously administered RNA interference (RNAi) therapeutic ARC-AAT and then with next-generation subcutaneously administered ARO-AAT were assessed by measuring AAT protein in serum of the PiZ transgenic mouse model and human volunteers. The impact of Z-AAT reduction by RNAi on liver disease phenotypes was evaluated in PiZ mice by measuring polymeric Z-AAT in the liver; expression of genes associated with fibrosis, autophagy, apoptosis, and redox regulation; inflammation; Z-AAT globule parameters; and tumor formation. Ultrastructure of the ER, mitochondria, and autophagosomes in hepatocytes was evaluated by electron microscopy. In mice, sustained RNAi treatment reduced hepatic Z-AAT polymer, restored ER and mitochondrial health, normalized expression of disease-associated genes, reduced inflammation, and prevented tumor formation. RNAi therapy holds promise for the treatment of patients with AATD-associated liver disease. ARO-AAT is currently in phase II/III clinical trials.

Rate and risk factors for rehospitalisation in sepsis survivors: systematic review and meta-analysis

PURPOSE

Sepsis survivors have a higher risk of rehospitalisation and of long-term mortality. We assessed the rate, diagnosis, and independent predictors for rehospitalisation in adult sepsis survivors.

METHODS

We searched for non-randomized studies and randomized clinical trials in MEDLINE, Cochrane Library, Web of Science, and EMBASE (OVID interface, 1992-October 2019). The search strategy used controlled vocabulary terms and text words for sepsis and hospital readmission, limited to humans, and English language. Two authors independently selected studies and extracted data using predefined criteria and data extraction forms.

RESULTS

The literature search identified 12,544 records. Among 56 studies (36 full and 20 conference abstracts) that met our inclusion criteria, all were non-randomised studies. Studies most often report 30-day rehospitalisation rate (mean 21.4%, 95% confidence interval [CI] 17.6-25.4%; N = 36 studies reporting 6,729,617 patients). The mean (95%CI) rehospitalisation rates increased from 9.3% (8.3-10.3%) by 7 days to 39.0% (22.0-59.4%) by 365 days. Infection was the most common rehospitalisation diagnosis. Risk factors that increased the rehospitalisation risk in sepsis survivors were generic characteristics such as older age, male, comorbidities, non-elective admissions, hospitalisation prior to index sepsis admission, and sepsis characteristics such as infection and illness severity, with hospital characteristics showing inconsistent associations. The overall certainty of evidence was moderate for rehospitalisation rates and low for risk factors.

CONCLUSIONS

Rehospitalisation events are common in sepsis survivors, with one in five rehospitalisation events occurring within 30 days of hospital discharge following an index sepsis admission. The generic and sepsis-specific characteristics at index sepsis admission are commonly reported risk factors for rehospitalisation.

REGISTRATION

PROSPERO CRD 42016039257, registered on 14-06-2016.

The Alpha-1 Antitrypsin Polymer Load Correlates With Hepatocyte Senescence, Fibrosis Stage and Liver-Related Mortality

Background

Alpha-1 antitrypsin deficiency (AATD) is an important, inherited cause of chronic liver disease. Marked variation in fibrosis stages in patients with homozygous deficiency and those factors that determine whether heterozygous carriers develop liver fibrosis, remain unexplained. Murine studies implicate polymerized alpha-1 antitrypsin (AAT) within hepatocytes as pathogenic.

Aims and Methods

The relationship between the quantity of polymerized AAT within hepatocytes (polymer load), stage of hepatic fibrosis and liver-related clinical outcomes (death, evolution to hepatocellular carcinoma, or need for liver transplantation) were investigated using liver tissue from 92 patients at first presentation with either homozygous or heterozygous AATD. Further tissue-based studies were undertaken to determine if polymerized AAT was associated with failure of cell cycle progression, accelerated aging or hepatocyte senescence by immunohistochemical analysis.

Results

The AAT polymer load correlated closely with hepatic fibrosis stage and long-term clinical outcome, independent of homozygous or heterozygous status. AAT polymers within hepatocytes correlated closely with failure of cell cycle progression assessed using cell cycle phase markers, accelerated aging manifest as shortened telomeres and other markers consistent with hepatocyte senescence manifest as the presence of nuclear p21 expression and enlarged nuclei. The proportion of p21 positive hepatocytes or hepatocytes with enlarged nuclei correlated with hepatic fibrosis stage and the long-term clinical outcome.

Conclusion

These data suggest that accumulation of AAT polymers within hepatocytes drives senescence. Quantitation of both the AAT polymer load or hepatocyte senescence markers correlated with hepatic fibrosis stage and the long-term clinical outcome. Either or both could be considered markers of disease severity and treatment response in clinical trials.

Liver Fibrosis and Metabolic Alterations in Adults With alpha-1-antitrypsin Deficiency Caused by the Pi*ZZ Mutation

BACKGROUND & AIMS

Alpha-1 antitrypsin deficiency (AATD) is among the most common genetic disorders. Severe AATD is caused by a homozygous mutation in the SERPINA1 gene that encodes the Glu342Lys substitution (called the Pi*Z mutation, Pi*ZZ genotype). Pi*ZZ carriers may develop lung and liver diseases. Mutation-associated lung disorders have been well studied, but less is known about the effects in liver. We assessed the liver disease burden and associated features in adults with this form of AATD.

METHODS

We collected data from 554 Pi*ZZ adults (403 in an exploratory cohort, 151 in a confirmatory cohort), in 9 European countries, with AATD who were homozygous for the Pi*Z mutation, and 234 adults without the Pi*Z mutation (controls), all without pre-existing liver disease. We collected data on demographic parameters, comorbidities, lung- and liver-related health, and blood samples for laboratory analysis. Liver fibrosis was assessed non-invasively via the serum tests Aspartate Aminotransferase to Platelet Ratio Index and HepaScore and via transient elastography. Liver steatosis was determined via transient elastography-based controlled attenuation parameter. We performed histologic analyses of livers from transgenic mice that overexpress the AATD-associated Pi*Z variant.

RESULTS

Serum levels of liver enzymes were significantly higher in Pi*ZZ carriers vs controls. Based on non-invasive tests for liver fibrosis, significant fibrosis was suspected in 20%-36% of Pi*ZZ carriers, whereas signs of advanced fibrosis were 9- to 20-fold more common in Pi*ZZ carriers compared to non-carriers. Male sex; age older than 50 years; increased levels of alanine aminotransferase, aspartate aminotransferase, or γ-glutamyl transferase; and low numbers of platelets were associated with higher liver fibrosis burden. We did not find evidence for a relationship between lung function and liver fibrosis. Controlled attenuation parameter ≥280 dB/m, suggesting severe steatosis, was detected in 39% of Pi*ZZ carriers vs 31% of controls. Carriers of Pi*ZZ had lower serum concentrations of triglyceride and low- and very-low-density lipoprotein cholesterol than controls, suggesting impaired hepatic secretion of lipid. Livers from Pi*Z-overexpressing mice had steatosis and down-regulation of genes involved in lipid secretion.

CONCLUSIONS

In studies of AATD adults with the Pi*ZZ mutation, and of Pi*Z-overexpressing mice, we found evidence of liver steatosis and impaired lipid secretion. We identified factors associated with significant liver fibrosis in patients, which could facilitate hepatologic assessment and counseling of individuals who carry the Pi*ZZ mutation. ClinicalTrials.gov Number NCT02929940.

Liver disease related to alpha1-antitrypsin deficiency in French children: The DEFI-ALPHA cohort

BACKGROUND & AIMS

To identify prognostic factors for liver disease in children with alpha-1 antitrypsin deficiency, irrespective of phenotype, using the DEFI-ALPHA cohort.

METHODS

Retrospective, then prospective from 2010, multicentre study including children known to have alpha-1 antitrypsin blood concentration below 0.8 g/L, born in France since 1989. Clinical and biological data were collected. Liver disease was classified as "severe" (portal hypertension, liver failure, liver transplantation or death); "moderate" (persistent abnormal liver biology without portal hypertension); and "mild/none" (normal or almost normal liver biology and native liver). Prognostic factors for severe liver disease were evaluated using a Cox semiparametric model.

RESULTS

In January 2017, 153 patients from 19 centres had been included; genotypes were PIZZ in 81.9%, PISZ in 8.1%, other in 10.0%. Mean ± SD follow-up was 4.7 ± 2.1 years. Half of patients had moderate liver disease. Twenty-eight children (18.3%) had severe liver disease (mean age 2.5 years, range: 0-11.6): diagnosis of alpha-1 antitrypsin deficiency was made before two months of age in 65.4%, genotypes were PIZZ in 25 (89.3%), PISZ in 2, PIM_like Z in 1, 15 children underwent liver transplantation, 1 child died at 3 years of age. Neonatal cholestasis was significantly associated with severe liver disease (P = 0.007).

CONCLUSION

Alpha-1 antitrypsin-deficient patients presenting with neonatal cholestasis were likely to develop severe liver disease. Some patients with non-homozygous ZZ genotype can develop severe liver disease, such as PISZ and M variants, when associated with predisposing factors. Further genetic studies will help to identify other factors involved in the development of liver complications.

Portuguese consensus document for the management of alpha-1-antitrypsin deficiency

Alpha-1-antitrypsin deficiency (AATD) is a genetic autosomal codominant disorder caused by mutations in SERPINA1 gene. It is one of the most prevalent genetic disorders, although it remains underdiagnosed. Whereas at international level there are several areas of consensus on this disorder, in Portugal, inter-hospital heterogeneity in clinical practice and resources available have been adding difficulties in reaching a diagnosis and in making therapeutic decisions in this group of patients. This raised a need to draft a document expressing a national consensus for AATD. To this end, a group of experts in this field was created within the Portuguese Pulmonology Society - Study group on AATD, in order to elaborate the current manuscript. The authors reviewed the existing literature and provide here general guidance and extensive recommendations for the diagnosis and management of AATD that can be adopted by Portuguese clinicians from different areas of Medicine. This article is part of a supplement entitled "Portuguese consensus document for the management of alpha-1-antitrypsin deficiency" which is sponsored by Sociedade Portuguesa de Pneumologia.

Assessment of liver fibrosis by transient elastography (Fibroscan®) in patients with A1AT deficiency

BACKGROUND

Alpha-1-antitrypsin deficiency (A1ATD) is a common genetic condition which predisposes to emphysema and liver disorders. It is estimated that 10-15% of homozygous individuals for the Z allele (PiZZ) may develop liver fibrosis. The optimal modalities to detect liver disease in PiZZ adult patients need to be defined. The aim of this prospective study was to perform a systematic non-invasive evaluation of the liver fibrosis by elastometry using Fibroscan^® in a cohort of A1ATD patients with emphysema.

METHODS

Patients followed in our respiratory unit were enrolled in this prospective study and underwent on the same day a physical examination, a biochemical profiling, an abdominal ultrasound (US) and a Fibroscan^®.

RESULTS

Twenty-nine PiZZ adults (19 male) were included. Median age was 50.4 yrs (21.5-67.2). Median serum A1AT level was 0.20 g/L (0.15-0.33). Liver Function Tests (LFT) were not normal in 2 patients and US was abnormal in 6 patients. Two patients had both abdnormal LFT and US. Fibroscan^® was technically feasible in 28/29 (97%) patients. Median liver stiffness was 4.5 kPa (2.8-32.8), and was > 7.2 kPa in 5/28 (18%) and > 14 kPa in 2/28 (7%) patients. Liver stiffness was increased in 2/2 (100%) patients with abnormal LFT and US, in 1/4 (25%) with abnormal LFT or US and in 2/22 (10%) patients with normal LFT and US.

CONCLUSIONS

Fibroscan^® is an easy and repeatable tool which can be used in PiZZ patients to screen for the presence of significant liver fibrosis and to identify patients at higher risk to develop liver complications in the future and who may benefit from a closer surveillance.

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.

Clinical and histologic features of adults with alpha-1 antitrypsin deficiency in a non-cirrhotic cohort

BACKGROUND & AIMS

Alpha-1 antitrypsin deficiency (AATD) is an uncommonly recognized cause of liver disease in adults, with descriptions of its natural history limited to case series and patient-reported data from disease registries. Liver pathology is limited to selected patients or unavailable. Therefore, we aimed to determine the prevalence and severity of liver fibrosis in an adult AATD population who were not known to have cirrhosis, while defining risk factors for fibrosis and testing non-invasive markers of disease.

METHODS

A total of 94 adults with classic genotype 'PI*ZZ' AATD were recruited from North America and prospectively enrolled in the study. Liver aminotransferases and markers of synthetic function, transient elastography, and liver biopsy were performed.

RESULTS

The prevalence of clinically significant liver fibrosis (F ≥ 2) was 35.1%. Alanine aminotransferase, aspartate aminotransferase and gamma-glutamyltransferase values were higher in the F ≥ 2 group. Metabolic syndrome was associated with the presence of clinically significant fibrosis (OR 14.2; 95% CI 3.7-55; p <0.001). Additionally, the presence of accumulated abnormal AAT in hepatocytes, portal inflammation, and hepatocellular degeneration were associated with clinically significant fibrosis. The accuracy of transient elastography to detect F ≥ 2 fibrosis was fair, with an AUC of 0.70 (95% CI 0.58-0.82).

CONCLUSIONS

Over one-third of asymptomatic and lung affected adults with 'PI*ZZ' AATD have significant underlying liver fibrosis. Liver biopsies demonstrated variable amounts of accumulated Z AAT. The risk of liver fibrosis increases in the presence of metabolic syndrome, accumulation of AAT in hepatocytes, and portal inflammation on baseline biopsy. The results support the hypothesis that liver disease in this genetic condition may be related to a "toxic gain of function" from accumulation of AAT in hepatocytes.

LAY SUMMARY

Individuals diagnosed with classic alpha-1 antitrypsin deficiency (ZZ) are at risk of liver injury and scarring, because of the accumulation of abnormal alpha-1 antitrypsin in the liver. A liver biopsy in ZZ individuals can demonstrate the accumulation of alpha-1 antitrypsin within the liver and identify if any associated liver scarring is present. Indviduals with large amounts of alpha-1 antitrypsin on biopsy may be at risk of liver injury and fibrosis. Additional common medical conditions of diabetes, obesity, high cholesterol, and hypertension (known as metabolic syndrome) are associated with a greater degree of liver injury. CLINICAL TRIAL NUMBER: clinicaltrials.gov NCT01810458.

Hepatic-targeted RNA interference provides robust and persistent knockdown of alpha-1 antitrypsin levels in ZZ patients

BACKGROUND & AIMS

Alpha-1 antitrypsin deficiency (AATD) is a genetic disorder causing pulmonary and liver disease. The PiZ mutation in AAT (SERPINA1) results in mis-folded AAT protein (Z-AAT) accumulating in hepatocytes, leading to fibrosis and cirrhosis. RNAi-based therapeutics silencing production of hepatic Z-AAT might benefit patients with AATD-associated liver disease. This study evaluated an RNAi therapeutic to silence production of AAT.

METHODS

Part A of this double-blind first-in-human study randomized 54 healthy volunteers (HVs) into single dose cohorts (two placebo: four active), receiving escalating doses of the investigational agent ARC-AAT from 0.38 to 8.0 mg/kg or placebo. Part B randomized 11 patients with PiZZ (homozygous for Z-AAT) genotype AATD, who received up to 4.0 mg/kg of ARC-AAT or placebo. Patients with baseline FibroScan® >11 kPa or forced expiratory volume in one second (FEV1) <60% were excluded. Assessments included safety, pharmacokinetics, and change in serum AAT concentrations.

RESULTS

A total of 36 HVs received ARC-AAT and 18 received placebo (part A). Seven PiZZ individuals received ARC-AAT and four received placebo (part B). A dose response in serum AAT reduction was observed at doses ≥4 mg/kg with similar relative reductions in PiZZ patients and HVs at 4 mg/kg and a maximum reduction of 76.1% (HVs) vs. 78.8% (PiZZ) at this dose. The time it took for serum AAT to return to baseline was similar for HV and PiZZ. There were no notable differences between HV and PiZZ safety parameters. The study was terminated early because of toxicity findings related to the delivery vehicle (ARC-EX1) seen in a non-human primate study.

CONCLUSION

PiZZ patients and HVs responded similarly to ARC-AAT. Deep and durable knockdown of hepatic AAT production based on observed reduction in serum AAT concentrations was demonstrated.

LAY SUMMARY

Accumulation of abnormal proteins in the livers of patients with alpha-1 antitrypsin deficiency may lead to decreased liver function and potentially liver failure. Therapeutics targeting the production of these abnormal proteins may be used to prevent or treat liver disease in patients with alpha-1 antitrypsin deficiency.

CLINICAL TRIAL REGISTRATION NUMBER

NCT02363946.

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 disease in adults with α1-antitrypsin deficiency

Background

The natural history of adult liver disease due to α1-antitrypsin deficiency (A1AD) remains poorly understood.

Objective

We investigated whether heterozygosity for the Z-allele predisposes for the development of clinically significant portal hypertension (CSPH). Moreover, we aimed to non-invasively assess the prevalence of liver fibrosis and hepatic steatosis in adults with A1AD treated by pulmonologists.

Methods

SERPINA1 rs28929474 (Z-allele) was genotyped in 315 patients with CSPH (hepatic venous pressure gradient ≥10 mmHg; cases) and 248 liver donors (controls). In addition, 31 adults with A1AD (Pi*ZZ/Pi*SZ) and 11 first-degree relatives (Pi*MZ/Pi*MS) underwent liver stiffness and controlled attenuation parameter (CAP) measurement.

Results

Heterozygosity for the Z-allele was observed in 6.7% of patients with CSPH and 2.8% of liver donors. Thus, harboring the Z-allele was associated with increased odds of CSPH (odds ratio: 2.47; 95% confidence interval: 1.03-5.9; P = 0.042). Among Pi*ZZ/Pi*SZ patients, 23%/3% had liver stiffness values indicative of liver fibrosis ( ≥F2/ ≥F3). Interestingly, 65%/52% of Pi*ZZ/Pi*SZ patients had CAP values indicative of hepatic steatosis ( ≥S1/ ≥S2).

Conclusions

Heterozygosity for the Z-allele predisposes for the development of CSPH, confirming its role as a genetic (co)factor in liver disease. Pi*ZZ/SZ patients rarely develop liver fibrosis ≥F3 during adulthood; however, liver fibrosis ≥F2 is common. Elevated CAP values hint at underlying hepatic steatosis, which might promote liver fibrosis progression.

Survival Advantage of Both Human Hepatocyte Xenografts and Genome-Edited Hepatocytes for Treatment of α-1 Antitrypsin Deficiency

Hepatocytes represent an important target for gene therapy and editing of single-gene disorders. In α-1 antitrypsin (AAT) deficiency, one missense mutation results in impaired secretion of AAT. In most patients, lung damage occurs due to a lack of AAT-mediated protection of lung elastin from neutrophil elastase. In some patients, accumulation of misfolded PiZ mutant AAT protein triggers hepatocyte injury, leading to inflammation and cirrhosis. We hypothesized that correcting the Z mutant defect in hepatocytes would confer a selective advantage for repopulation of hepatocytes within an intact liver. A human PiZ allele was crossed onto an immune-deficient (NSG) strain to create a recipient strain (NSG-PiZ) for human hepatocyte xenotransplantation. Results indicate that NSG-PiZ recipients support heightened engraftment of normal human primary hepatocytes as compared with NSG recipients. This model can therefore be used to test hepatocyte cell therapies for AATD, but more broadly it serves as a simple, highly reproducible liver xenograft model. Finally, a promoterless adeno-associated virus (AAV) vector, expressing a wild-type AAT and a synthetic miRNA to silence the endogenous allele, was integrated into the albumin locus. This gene-editing approach leads to a selective advantage of edited hepatocytes, by silencing the mutant protein and augmenting normal AAT production, and improvement of the liver pathology.

Liver Involvement in Patients With PiZZ-Emphysema, Candidates for Lung Transplantation

Information about the prevalence and nature of liver disorders in adults with alpha1-antitrypsin deficiency is scarce. At our center, systematic liver biopsy screening is part of the evaluation before lung transplantation (LT) in the emphysema patients with the PiZZ phenotype. Our aim was to report our experience with this prospective screening. Clinical, liver function, and imaging parameters as well as liver histology data were analyzed for 23 consecutive adult patients with PiZZ severe emphysema referred to our center for consideration of LT from 2006 to 2014. Overall 20 (87%) featured chronic liver disease characterized by a chronic inflammation and/or a significant portal fibrosis on histology. Two of the 23 patients (8.7%) had septal fibrosis according to the Metavir and Ishak scores and met our definition of severe chronic liver disease. They were both clinically asymptomatic with normal liver function tests. On abdominal ultrasonography, the liver appeared normal in one patient and with abnormal contours in the other. Our data indicate that in adults with PiZZ-related emphysema being evaluated for LT, most patients had some histologic involvement. The prevalence of severe liver dysfunction is <10%.

Therapeutic Options in Alpha-1 Antitrypsin Deficiency: Liver Transplantation

Alpha-1 antitrypsin deficiency is the commonest genetic condition leading to liver transplantation in childhood. It remains unclear why only a minority of individuals carrying homozygous PiZ phenotype has liver disease, but also why of those only about a quarter develops end stage liver disease, requiring liver transplantation. This intervention has now become routine worldwide with 1-year patient survival rates well above 90%. As for all autosomal recessive conditions liver donation from anonymous cadaveric sources is preferred to living related parental donors, due to their presumed heterozygous state.

Update on alpha-1 antitrypsin deficiency: New therapies

α1-Antitrypsin deficiency is characterised by the misfolding and intracellular polymerisation of mutant α1-antitrypsin within the endoplasmic reticulum of hepatocytes. The retention of mutant protein causes hepatic damage and cirrhosis whilst the lack of an important circulating protease inhibitor predisposes the individuals with severe α1-antitrypsin deficiency to early onset emphysema. Our work over the past 25years has led to new paradigms for the liver and lung disease associated with α1-antitrypsin deficiency. We review here the molecular pathology of the cirrhosis and emphysema associated with α1-antitrypsin deficiency and show how an understanding of this condition provided the paradigm for a wider group of disorders that we have termed the serpinopathies. The detailed understanding of the pathobiology of α1-antitrypsin deficiency has identified important disease mechanisms to target. As a result, several novel parallel and complementary therapeutic approaches are in development with some now in clinical trials. We provide an overview of these new therapies for the liver and lung disease associated with α1-antitrypsin deficiency.

Magnetic resonance elastography identifies fibrosis in adults with alpha-1 antitrypsin deficiency liver disease: a prospective study

BACKGROUND

Limited data exist on the clinical presentation and non-invasive detection of liver fibrosis in adults with homozygous Z genotype alpha-1 antitrypsin (AAT) deficiency.

AIMS

To compare demographic, biochemical, histological and imaging data of AAT deficient patients to normal-control and biopsy-proven non-alcoholic fatty liver disease (NAFLD) patients, and to assess the diagnostic accuracy of magnetic resonance elastography (MRE) in detecting fibrosis in AAT deficiency.

METHODS

Study includes 33 participants, 11 per group, who underwent clinical research evaluation, liver biopsy (AAT and NAFLD groups), and MRE. Histological fibrosis was quantified using a modified Ishak 6-point scale and liver stiffness by MRE. Diagnostic performance of MRE in detecting fibrosis was assessed by receiver operating characteristic (ROC) analysis.

RESULTS

Mean (±s.d.) of age and BMI of normal-control, AAT and NAFLD groups was 57 (±19), 57 (±18), and 57 (±13) years, and 22.7 (±2.5), 24.8 (±4.0) and 31.0 (±5.1) kg/m(2) respectively. Serum ALT [mean ± s.d.] was similar within normal-control [16.4 ± 4.0] and AAT groups [23.5 ± 10.8], but was significantly lower in AAT than NAFLD even after adjustment for stage of fibrosis (P < 0.05, P = 0.0172). For fibrosis detection, MRE-estimated stiffness had an area under the ROC curve of 0.90 (P < 0.0001); an MRE threshold of ≥3.0 kPa provided 88.9% accuracy, with 80% sensitivity and 100% specificity to detect presence of any fibrosis (stage ≥1).

CONCLUSIONS

This pilot prospective study suggests magnetic resonance elastography may be accurate for identifying fibrosis in patients with alpha-1 antitrypsin deficiency. Larger validation studies are warranted.

α1-Antitrypsin Deficiency

α1-Antitrypsin deficiency is an autosomal codominant condition that predisposes to emphysema and cirrhosis. The condition is common but grossly under-recognized. Identifying patients' α1-antitrypsin deficiency has important management implications (ie, smoking cessation, genetic and occupational counseling, and specific treatment with the infusion of pooled human plasma α1-antitrypsin). The weight of evidence suggests that augmentation therapy slows the progression of emphysema in individuals with severe α1-antitrypsin deficiency.

The Diagnosis and Management of Alpha-1 Antitrypsin Deficiency in the Adult

Background: The diagnosis and clinical management of adults with alpha-1 antitrypsin deficiency (AATD) have been the subject of ongoing debate, ever since the publication of the first American Thoracic Society guideline statement in 1989.¹ In 2003, the "American Thoracic Society (ATS)/European Respiratory Society (ERS) Statement: Standards for the Diagnosis and Management of Individuals with Alpha-1 Antitrypsin Deficiency" made a series of evidence-based recommendations, including a strong recommendation for broad-based diagnostic testing of all symptomatic adults with chronic obstructive pulmonary disease (COPD).² Even so, AATD remains widely under-recognized. To update the 2003 systematic review and clinical guidance, the Alpha-1 Foundation sponsored a committee of experts to examine all relevant, recent literature in order to provide concise recommendations for the diagnosis and management of individuals with AATD. Purpose: To provide recommendations for: (1) the performance and interpretation of diagnostic testing for AATD, and (2) the current management of adults with AATD and its associated medical conditions. Methods: A systematic review addressing the most pressing questions asked by clinicians (clinician-centric) was performed to identify citations related to AATD that were published since the 2003 comprehensive review, specifically evaluating publications between January 2002 and December 2014. Important, more recent publications were solicited from the writing committee members as well. The combined comprehensive literature reviews of the 2003 document and this current review comprise the evidence upon which the committee's conclusions and recommendations are based. Results: Recommendations for the diagnosis and management of AATD were formulated by the committee. Conclusions: The major recommendations continue to endorse and reinforce the importance of testing for AATD in all adults with symptomatic fixed airflow obstruction, whether clinically labeled as COPD or asthma. Individuals with unexplained bronchiectasis or liver disease also should be tested. Family testing of first-degree relatives is currently the most efficient detection technique. In general, individuals with AATD and emphysema, bronchiectasis, and/or liver disease should be managed according to usual guidelines for these clinical conditions. In countries where intravenous augmentation therapy with purified pooled human plasma-derived alpha-1 antitrypsin is available, recent evidence now provides strong support for its use in appropriate individuals with lung disease due to AATD.

Deficient and Null Variants of SERPINA1 Are Proteotoxic in a Caenorhabditis elegans Model of α1-Antitrypsin Deficiency

α1-antitrypsin deficiency (ATD) predisposes patients to both loss-of-function (emphysema) and gain-of-function (liver cirrhosis) phenotypes depending on the type of mutation. Although the Z mutation (ATZ) is the most prevalent cause of ATD, >120 mutant alleles have been identified. In general, these mutations are classified as deficient (<20% normal plasma levels) or null (<1% normal levels) alleles. The deficient alleles, like ATZ, misfold in the ER where they accumulate as toxic monomers, oligomers and aggregates. Thus, deficient alleles may predispose to both gain- and loss-of-function phenotypes. Null variants, if translated, typically yield truncated proteins that are efficiently degraded after being transiently retained in the ER. Clinically, null alleles are only associated with the loss-of-function phenotype. We recently developed a C. elegans model of ATD in order to further elucidate the mechanisms of proteotoxicity (gain-of-function phenotype) induced by the aggregation-prone deficient allele, ATZ. The goal of this study was to use this C. elegans model to determine whether different types of deficient and null alleles, which differentially affect polymerization and secretion rates, correlated to any extent with proteotoxicity. Animals expressing the deficient alleles, Mmalton, Siiyama and S (ATS), showed overall toxicity comparable to that observed in patients. Interestingly, Siiyama expressing animals had smaller intracellular inclusions than ATZ yet appeared to have a greater negative effect on animal fitness. Surprisingly, the null mutants, although efficiently degraded, showed a relatively mild gain-of-function proteotoxic phenotype. However, since null variant proteins are degraded differently and do not appear to accumulate, their mechanism of proteotoxicity is likely to be different to that of polymerizing, deficient mutants. Taken together, these studies showed that C. elegans is an inexpensive tool to assess the proteotoxicity of different AT variants using a transgenic approach.

Low serum levels of alpha1 anti-trypsin (α1-AT) and risk of airflow obstruction in non-primary α1-AT-deficient patients with compensated chronic liver disease

Background

Alpha₁ anti-trypsin (α₁-AT), a serine protease inhibitor synthesized in the liver, is a major circulating antiprotease that provides defense against proteolytic damage in several tissues. Its deficiency is associated with airflow obstruction. The present study aimed to explore the role of α₁-AT as a biomarker of airflow performance in chronic liver disease (CLD).

Material/Methods

Serum α₁-AT levels and lung function (spirometry) were evaluated in non-primary α₁-AT-deficient, alcoholic CLD patients without evident respiratory limitations.

Results

Thirty-four patients with airflow obstruction (n=11), airflow restriction (n=12), and normal airflow (n=11, age-matched controls) were eligible. α1-AT was decreased in the airflow obstruction group. ROC-cutoff α₁-AT=24 mg/dL effectively discriminated airflow obstruction (AUC=0.687) and was associated with a 10-fold higher risk (p=0.0007).

Conclusions

Lower α₁-AT increased the risk of airflow obstruction in CLD patients without primary α₁-AT deficiency.

Severe postoperative wound healing disturbance in a patient with alpha-1-antitrypsin deficiency: the impact of augmentation therapy

Wound healing disturbance is a common complication following surgery, but the underlying cause sometimes remains elusive. A 50-year-old Caucasian male developed an initially misunderstood severe wound healing disturbance following colon and abdominal wall surgery. An untreated alpha-1-antitrypsin (AAT) deficiency in the patient's medical history, known since 20 years and clinically apparent as a mild to moderate chronic obstructive pulmonary disease, was eventually found to be at its origin. Further clinical work-up showed AAT serum levels below 30% of the lower reference value; phenotype testing showed a ZZ phenotype and a biopsy taken from the wound area showed the characteristic, disease-related histological pattern of necrotising panniculitits. Augmentation therapy with plasma AAT was initiated and within a few weeks, rapid and adequate would healing was observed. AAT deficiency is an uncommon but clinically significant, possible cause of wound healing disturbances. An augmentation therapy ought to be considered in affected patients during the perioperative period.

α-1-Antitrypsin deficiency: clinical variability, assessment, and treatment

The recognition of α-1-antitrypsin deficiency, its function, and its role in predisposition to the development of severe emphysema was a watershed in our understanding of the pathophysiology of the condition. This led to the concept and development of intravenous replacement therapy used worldwide to protect against lung damage induced by neutrophil elastase. Nevertheless, much remained unknown about the deficiency and its impact, although in recent years the genetic and clinical variations in manifestation have provided new insights into assessing impact, efficacy of therapy, and development of new therapeutic strategies, including gene therapy, and outcome measures, such as biomarkers and computed tomography. The current article reviews this progress over the preceding 50 years.

Outcomes for recipients of liver transplantation for alpha-1-antitrypsin deficiency–related cirrhosis

Alpha-1-antitrypsin (AAT) deficiency is a rare genetic disease caused by an abnormal production of the serine protease inhibitor AAT. Liver transplantation (LT) cures cirrhosis caused by AAT deficiency and restores the normal production of AAT. There are few reports on the post-LT outcomes of patients with AAT deficiency. The aim of this study was to determine the characteristics and outcomes of patients undergoing LT for AAT deficiency at 3 large transplant centers. All patients undergoing LT at these 3 transplant centers from 1987 to 2012 for AAT deficiency (ZZ or SZ phenotype) were included. The most recent 50 patients with the MZ phenotype were also included for comparison. Data were collected retrospectively from internal databases and medical records. Seventy-three patients (50 with the ZZ phenotype and 23 with the SZ phenotype)underwent LT. The mean age was 52.8 years, and the majority of the patients (75.6%) were men. Before LT, serum AAT levels were lower for the ZZ patients versus the SZ patients (28.3 versus 58.0 mg/dL, P < 0.001). More than 40% of the SZ patients had an additional liver disease, whereas 8% in the ZZ group and 90% in the MZ group did. Before LT, there was no significant difference in pulmonary function between the ZZ and SZ groups. Seventeen patients (all with ZZ phenotype)had pulmonary function tests performed before and after LT. The forced expiratory volume in 1 second (FEV1) continued to decline for the majority. The 1-, 3-, 5-, and 10-year post-LT survival rates were 86%, 83%, 80%, and 72%, respectively, for the ZZ patients and 91%, 86%, 79%, and 79%, respectively, for the SZ patients. In conclusion, survival after LT for patients with ZZ or SZ AAT deficiency is excellent. Despite the normalization of AAT levels after LT, FEV1 continues to decline unexpectedly after LT in some ZZ and SZ patients.

Disease associations in alpha-1-antitrypsin deficiency

INTRODUCTION

In addition to emphysema alpha-1-antitrypsin deficiency (AATD) has been shown to be associated with several inflammatory conditions, including bronchiectasis, vasculitis, (in particular Wegener's granulomatosis), and panniculitis, suggesting neutrophil proteinases also play a role in their pathophysiology. However, it remains unknown whether other inflammatory diseases are also more prevalent in AATD than the general population. The current study describes the prevalence of other co-morbidities in AATD with particular emphasis on inflammatory bowel disease.

METHODS AND RESULTS

The case notes of 651 PiZZ or PiZnull patients attending the UK national centre for AATD between 1996 and 2011 were reviewed. The prevalence of inflammatory bowel disease (1.5%) was higher than that predicted in the UK (0.4%). Ten patients had a confirmed diagnosis of ulcerative colitis, and 1 had Crohn's disease. In 2 cases there was a family history of inflammatory bowel disease and all but 1 patient were ex or never smokers. There was also a higher prevalence of hypothyroidism in this patient group than expected for the UK population - 26 cases (7.2% of females and 1.3% of males).

CONCLUSIONS

The current study of the UK cohort of patients with AATD confirmed a higher prevalence of ulcerative colitis than would be expected in the general population, providing further evidence of a potential link between these 2 conditions. In addition, the data suggested a potential link between hypothyroidism and AATD.

The parallel lives of alpha1-antitrypsin deficiency and pulmonary alveolar proteinosis

In 1963, five cases of alpha1-antitrypsin deficiency were reported in the scientific literature, as well as an attempt to treat pulmonary alveolar proteinosis by a massive washing of the lung (whole lung lavage). Now, fifty years later, it seems the ideal moment not only to commemorate these publications, but also to point out the influence both papers had in the following decades and how knowledge on these two fascinating rare respiratory disorders progressed over the years. This paper is therefore not aimed at being a comprehensive review for both disorders, but rather at comparing the evolution of alpha1-antitrypsin, a rare disorder, with that of pulmonary alveolar proteinosis, an ultra-rare disease. We wanted to emphasize how all stakeholders might contribute to the dissemination of the awareness of rare diseases, that need to be chaperoned from the ghetto of neglected disorders to the dignity of recognizable and treatable disorders.

Pulmonary contraindications, indications and MELD exceptions for liver transplantation: a contemporary view and look forward

Pulmonary concerns in liver transplant candidates have intraoperative and outcome implications. Evolving MELD exception policies address transplant priority for problems such as hepatopulmonary syndrome, portopulmonary hypertension, and hemorrhagic hereditary telangiectasia. Other pulmonary issues such as refractory hepatic hydrothorax, advanced chronic obstructive lung disease (including alpha-1 antitrypsin deficiency) and indeterminate pulmonary nodules may affect liver transplant consideration. Herein, we discuss current pulmonary-related contraindications, indications and MELD exception policies for liver transplantation, suggesting future considerations.