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

Review article: New developments in biomarkers and clinical drug development in alpha-1 antitrypsin deficiency-related liver disease

BACKGROUND

Alpha-1 antitrypsin liver disease (AATLD) occurs in a subset of patients with alpha-1 antitrypsin deficiency. Risk factors for disease progression and specific pathophysiologic features are not well known and validated non-invasive assessments for disease severity are lacking. Currently, there are no approved treatments for AATLD.

AIMS

To outline existing understanding of AATLD and to identify knowledge gaps critical to improving clinical trial design and development of new treatments.

METHODS

This report was developed following a multi-stakeholder forum organised by the Alpha-1 Antitrypsin Deficiency Related Liver Disease Expert Panel in which experts presented an overview of the available literature on this topic.

RESULTS

AATLD results from a 'gain of toxic function' and primarily manifests in those with the homozygous Pi*ZZ genotype. Accumulation of misfolded 'Z' AAT protein in liver cells triggers intracellular hepatocyte injury which may ultimately lead to hepatic fibrosis. Male gender, age over 50 years, persistently elevated liver tests, concomitant hepatitis B or C virus infection, and metabolic syndrome, including obesity and type 2 diabetes mellitus, are known risk factors for adult AATLD. While the gold standard for assessing AATLD disease activity is liver histology, less invasive measures with low intra- and inter-observer variability are needed. Measurement of liver stiffness shows promise; validated thresholds for staging AATLD are in development. Such advances will help patients by enabling risk stratification and personalised surveillance, along with streamlining the development process for novel therapies.

CONCLUSIONS

This inaugural forum generated a list of recommendations to address unmet needs in the field of AATLD.

Interpretation, Reporting, and Clinical Applications of Liver MR Elastography

Chronic liver disease is highly prevalent and often leads to fibrosis or cirrhosis and complications such as liver failure and hepatocellular carcinoma. The diagnosis and staging of liver fibrosis is crucial to determine management and mitigate complications. Liver biopsy for histologic assessment has limitations such as sampling bias and high interreader variability that reduce precision, which is particularly challenging in longitudinal monitoring. MR elastography (MRE) is considered the most accurate noninvasive technique for diagnosing and staging liver fibrosis. In MRE, low-frequency vibrations are applied to the abdomen, and the propagation of shear waves through the liver is analyzed to measure liver stiffness, a biomarker for the detection and staging of liver fibrosis. As MRE has become more widely used in clinical care and research, different contexts of use have emerged. This review focuses on the latest developments in the use of MRE for the assessment of liver fibrosis; provides guidance for image acquisition and interpretation; summarizes diagnostic performance, along with thresholds for diagnosis and staging of liver fibrosis; discusses current and emerging clinical applications; and describes the latest technical developments.

Future Perspectives in the Diagnosis and Treatment of Liver Disease Associated with Alpha-1 Antitrypsin Deficiency

Alpha-1 antitrypsin deficiency (AATD) is one of the most common genetic diseases and is caused by mutations in the SERPINA1 gene. The homozygous Pi*Z variant is responsible for the majority of the classic severe form of alpha-1 antitrypsin deficiency, which is characterized by markedly decreased levels of serum alpha-1 antitrypsin (AAT) with a strong predisposition to lung and liver disease. The diagnosis and early treatment of AATD-associated liver disease are challenges in clinical practice. In this review, the authors aim to summarize the current evidence of the non-invasive methods in the assessment of liver fibrosis, as well as to elucidate the main therapeutic strategies under investigation that may emerge in the near future.

Meta-analysis: Prevalence of significant or advanced fibrosis in adults with alpha-1-antitrypsin deficiency

BACKGROUND

The prevalence of liver fibrosis detected by non-invasive imaging in alpha-1-antitrypsin (AAT) deficiency has not been systematically assessed.

AIMS

We conducted a systematic review and meta-analysis to determine the prevalence of significant fibrosis and advanced fibrosis in AAT deficiency based on non-invasive imaging.

METHODS

Medline and Embase electronic databases were searched for studies from inception to 13 November 2022 that provided data for the prevalence of fibrosis in adults with AAT deficiency. A generalised linear mixed model with Clopper-Pearson intervals was used to pool single-arm outcomes.

RESULTS

Of the 214 records identified, 8 studies were included. Five studies assessed fibrosis using vibration-controlled transient elastography. The prevalence of significant fibrosis (defined as ≥7.1 kPA) in Z homozygosity, Z heterozygosity and non-carrier status was 22.10% (five studies, 95% CI: 17.07-28.12), 9.24% (three studies, 95% CI: 4.68-17.45) and 5.38% (one study, 95% CI: 3.27-8.73), respectively, p < 0.0001, and the prevalence of advanced fibrosis (defined as ≥9.5 kPa) was 8.13% (five studies, 95% CI: 4.60-13.96), 2.96% (three studies, 95% CI: 1.49-5.81) and 1.08% (one study, 95% CI: 0.35-3.28), respectively, p = 0.003. There were limited data regarding the use of magnetic resonance elastography or acoustic radiation force impulse to assess for fibrosis.

CONCLUSION

More than one in five adult individuals with AAT deficiency and Z homozygosity harbour significant fibrosis, and nearly 1 in 10 harbours advanced fibrosis. The risk of fibrosis increases incrementally with the frequency of Pi*Z mutations.

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: A re-surfacing adult liver disorder

Alpha-1 antitrypsin deficiency (AATD) arises from mutations in the SERPINA1 gene encoding alpha-1 antitrypsin (AAT) that lead to AAT retention in the endoplasmic reticulum of hepatocytes, causing proteotoxic liver injury and loss-of-function lung disease. The homozygous Pi∗Z mutation (Pi∗ZZ genotype) is responsible for the majority of severe AATD cases and can precipitate both paediatric and adult liver diseases, while the heterozygous Pi∗Z mutation (Pi∗MZ genotype) is an established genetic modifier of liver disease. We review genotype-related hepatic phenotypes/disease predispositions. We also describe the mechanisms and factors promoting the development of liver disease, as well as approaches to evaluate the extent of liver fibrosis. Finally, we discuss emerging diagnostic and therapeutic approaches for the clinical management of this often neglected disorder.

Non-invasive diagnosis and follow-up of rare genetic liver diseases

Rare genetic liver diseases can result in multi-systemic damage, which may compromise the patient's prognosis. Wilson's disease and alpha-1 antitrypsin deficiency must be investigated in any patient with unexplained liver disease. Cystic fibrosis screening of new-borns is now implemented in most high-prevalence countries. The diagnosis of these diseases can be strongly suggested with specific non-invasive tests. Molecular analysis gene for these diseases is long and tedious but is recommended to confirm the diagnosis and help for the family screening. Liver biopsy is not systematic and is discussed when it helps diagnosis. Currently, for these three diseases, non-invasive fibrosis markers could identify patients with risk of cirrhosis and complications. Rare genetic liver diseases can result in multi-systemic damage, which may compromise the patient's prognosis. Wilson's disease, must be investigated in any patient with unexplained liver disease and/or unexplained neurological or neuropsychiatric disorders. The diagnosis is based on a combination of clinical, biological features, including copper balance. The exchangeable copper/total copper ratio is a new sensible and specific biological marker, useful for the diagnosis of the disease. Timely diagnosis and treatment will prevent serious complications from the disease. Neurological evaluation and familial screening are essential in patients with Wilson's disease.

Liver disease with unknown etiology - have you ruled out alpha-1 antitrypsin deficiency?

Although a less well-known consequence of alpha-1 antitrypsin deficiency (AATD) liver disease is the second leading cause of death among patients with the condition. The alpha-1 antitrypsin (AAT) protein is produced by hepatocytes within the liver, which retain pathological variants of AAT instead of secreting the proteinase inhibitor into the systemic circulation. This intracellular retention is caused by inefficient folding and polymerization of mutant AAT and the accumulation of these AAT aggregates leads to diverse manifestations of liver disease, which can present differently in both children and adults. The progression from hepatocyte apoptosis to liver inflammation, fibrosis and cirrhosis, and liver failure is still not fully understood, but in older patients, liver disease can surpass lung disease as the principal cause of death. Liver function tests (LFTs) can measure plasma levels of liver enzymes to assess liver function but require careful interpretation. Non-invasive tests are being developed that can detect early liver disease, but liver biopsy is still the gold standard for assessing liver fibrosis once abnormal LFTs have been detected in a patient. Currently, there is no licensed treatment for AATD-related liver disease (intravenous AAT therapy is not indicated for this purpose), but liver transplantation is associated with positive outcomes and may even slow emphysema progression. Therefore, new strategies are being developed to address treatment of AATD-related liver disease, such as accelerating degradation of mutant AAT and assisting hepatocytes in the folding and secretion of mutant AAT, but these approaches remain at early stages of development.

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.

Other types of diffuse liver disease: is there a way to do it?

There are a variety of less common diffuse liver diseases that can be asymptomatic or cause severe liver dysfunction. For the majority of them, the association of clinical, laboratory, and imaging findings are needed to narrow the differential diagnosis. In this article, we will review and describe the rarer diffuse liver diseases including drug-related liver disease, inflammatory and infectious diseases, and deposition disorders such as amyloidosis, glycogen storage disease, Wilson's disease, and alpha-1 antitrypsin deficiency. Abdominal radiologists should be familiar with the imaging features of different types of diffuse liver diseases to help the multidisciplinary team involved in the treatment of these patients. The data related to some of these conditions are scarce and sometimes experimental, but we want to demonstrate to the reader the value of imaging techniques in their analysis and introduce the potential of new imaging methods.

A Microbial Signature Identifies Advanced Fibrosis in Patients with Chronic Liver Disease Mainly Due to NAFLD

The presence of advanced fibrosis is an important measure of the severity of chronic liver disease. Prior works that have examined the gut microbiome as a novel biomarker for advanced fibrosis have only examined patients with nonalcoholic fatty liver disease. Therefore, our goal was to examine the gut microbiome across varying etiologies of liver disease to create a predictive model for liver fibrosis based upon a microbial signature. Stool samples were obtained from patients with chronic liver disease (n = 50) undergoing FibroScan (ultrasound elastography) at the VA Greater Los Angeles Healthcare System. Healthy control patients (n = 25) were also recruited as a reference population. Fecal samples underwent 16S ribosomal RNA sequencing. Using differentially abundant microbes, a random forest classifier model was created to distinguish advanced fibrosis from mild/moderate fibrosis. The findings were then validated in a separate cohort of chronic liver disease patients (n = 37). Etiologies for liver disease included non-alcoholic liver disease (58.0%), hepatitis C (26.0%), hepatitis B (10.0%), and alcohol (6.0%). Microbiome composition was distinct in liver patients with advanced fibrosis compared to those with minimal fibrosis and healthy controls (p = 0.003). In multivariate negative binomial modeling, 26 bacterial taxa were differentially abundant in patients with advanced fibrosis as compared to those with minimal/moderate fibrosis (q-value < 0.05). A random forests classifier based on these taxa had an AUROC of 0.90 to predict advanced fibrosis. Prevotella copri, which was enriched in patients with advanced fibrosis, was the most strongly predictive microbe in the classifier. The classifier had an AUROC of 0.82 for advanced fibrosis in the validation cohort and Prevotella copri remained the strongest predictive microbe for advanced fibrosis. There is a distinct microbial signature for patients with advanced fibrosis independent of liver disease etiology and other comorbidities. These results suggest that microbial profiles can be used as a non-invasive marker for advanced fibrosis and support the hypothesis that microbes and their metabolites contribute to hepatic fibrosis.

Genetic variants that associate with cirrhosis have pleiotropic effects on human traits

BACKGROUND AND AIMS

Cirrhosis is characterized by extensive fibrosis of the liver and is a major cause of liver-related mortality. Cirrhosis is partially heritable but genetic contributions to cirrhosis have not been systemically explored. Here, we carry out association analyses with cirrhosis in two large biobanks and determine the effects of cirrhosis associated variants on multiple human disease/traits.

METHODS

We carried out a genome-wide association analysis of cirrhosis as a diagnosis in UK BioBank (UKBB; 1088 cases vs. 407 873 controls) and then tested top-associating loci for replication with cirrhosis in a hospital-based cohort from the Michigan Genomics Initiative (MGI; 875 cases of cirrhosis vs. 30 346 controls). For replicating variants or variants previously associated with cirrhosis that also affected cirrhosis in UKBB or MGI, we determined single nucleotide polymorphism effects on all other diagnoses in UKBB (PheWAS), common metabolic traits/diseases and serum/plasma metabolites.

RESULTS

Unbiased genome-wide association study identified variants in/near PNPLA3 and HFE, and candidate variant analysis identified variants in/near TM6SF2, MBOAT7, SERPINA1, HSD17B13, STAT4 and IFNL4 that reproducibly affected cirrhosis. Most affected liver enzyme concentrations and/or aspartate transaminase-to-platelet ratio index. PheWAS, metabolic trait and serum/plasma metabolite association analyses revealed effects of these variants on lipid, inflammatory and other processes including new effects on many human diseases and traits.

CONCLUSIONS

We identified eight loci that reproducibly associate with population-based cirrhosis and define their diverse effects on human diseases and traits.

Non-Invasive Assessment and Management of Liver Involvement in Adults With Alpha-1 Antitrypsin Deficiency

Alpha-1 antitrypsin deficiency (AATD) is a systemic disorder affecting mainly the lung and the liver and is caused by mutations in SERPINA1, the AAT gene. A homozygous "Pi*Z" mutation (Pi*ZZ genotype) may cause liver fibrosis on its own independently of pulmonary AATD manifestation, while heterozygous Pi*Z carriage (Pi*MZ genotype) is considered a strong risk factor for development of liver cirrhosis in patients with concomitant liver disease such as alcoholic and non-alcoholic liver disease. In Pi*ZZ homozygotes, liver disease constitutes the second leading cause of death and is highly heterogeneous. About 35% of Pi*ZZ individuals display significant liver fibrosis on biopsy (i.e., fibrosis stage ≥ 2 on scale 0-4). Among non-invasive methods for liver fibrosis assessment, liver stiffness measurement (LSM) via vibration-controlled transient elastography (VCTE) has been most widely evaluated. Based on these data, Pi*ZZ adults have 20x increased odds of developing advanced liver fibrosis (i.e., fibrosis stage ≥ 3) than adults without AAT mutation. Risk factors for accelerated fibrosis progression are male sex, age ≥ 50 years, alcohol misuse, obesity, diabetes mellitus, or metabolic syndrome. Unlike VCTE, other ultrasound- and magnetic resonance-based elastography methods have been assessed in small cohorts of Pi*ZZ individuals and remain to be comprehensively validated. Among blood-based fibrosis tests, AST-to-platelet ratio index (APRI) correlates moderately with histologic fibrosis stage and LSM. Given APRI's wide availability, it can be used for risk stratification as an adjunct to LSM or when LSM is not at hand. Despite recent efforts, AATD-related liver disease, especially for genotypes other than Pi*ZZ, remains greatly understudied. AATD individuals should be offered liver biochemistry, liver ultrasound, and non-invasive fibrosis assessment at the time of diagnosis to detect potential complications and for proper risk stratification. If signs of AATD-related liver disease occur (i.e., pathologic fibrosis test or repeatedly elevated liver enzymes), patients should be referred to a health care center specialized in AATD-related liver disease and be screened for potentially treatable comorbidities. To exclude the latter, they may need a liver biopsy. Moreover, every health care provider of an AATD individual should be aware of the potential liver manifestation, counsel their patient on modifiable hepatic risk factors, and offer them regular liver check-ups.

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.

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.

Liver Fibrosis Quantification by Magnetic Resonance Imaging

Liver fibrosis is a hallmark of chronic liver disease characterized by the excessive accumulation of extracellular matrix proteins. Although liver biopsy is the reference standard for diagnosis and staging of liver fibrosis, it has some limitations, including potential pain, sampling variability, and low patient acceptance. Hence, there has been an effort to develop noninvasive imaging techniques for diagnosis, staging, and monitoring of liver fibrosis. Many quantitative techniques have been implemented on magnetic resonance imaging (MRI) for this indication. The most widely validated technique is magnetic resonance elastography, which aims to measure viscoelastic properties of the liver and relate them to fibrosis stage. Several additional MRI methods have been developed or adapted to liver fibrosis quantification. Diffusion-weighted imaging measures the Brownian motion of water molecules which is restricted by collagen fibers. Texture analysis assesses the changes in the texture of liver parenchyma associated with fibrosis. Perfusion imaging relies on signal intensity and pharmacokinetic models to extract quantitative perfusion parameters. Hepatocellular function, which decreases with increasing fibrosis stage, can be estimated by the uptake of hepatobiliary contrast agents. Strain imaging measures liver deformation in response to physiological motion such as cardiac contraction. T1ρ quantification is an investigational technique, which measures the spin-lattice relaxation time in the rotating frame. This article will review the MRI techniques used in liver fibrosis staging, their advantages and limitations, and diagnostic performance. We will briefly discuss future directions, such as longitudinal monitoring of disease, prediction of portal hypertension, and risk stratification of hepatocellular carcinoma.

Comparison of non-invasive assessment of liver fibrosis in patients with alpha1-antitrypsin deficiency using magnetic resonance elastography (MRE), acoustic radiation force impulse (ARFI) Quantification, and 2D-shear wave elastography (2D-SWE)

PURPOSE

Although it has been known for decades that patients with alpha1-antitrypsin deficiency (AATD) have an increased risk of cirrhosis and hepatocellular carcinoma, limited data exist on non-invasive imaging-based methods for assessing liver fibrosis such as magnetic resonance elastography (MRE) and acoustic radiation force impulse (ARFI) quantification, and no data exist on 2D-shear wave elastography (2D-SWE). Therefore, the purpose of this study is to evaluate and compare the applicability of different elastography methods for the assessment of AATD-related liver fibrosis.

METHODS

Fifteen clinically asymptomatic AATD patients (11 homozygous PiZZ, 4 heterozygous PiMZ) and 16 matched healthy volunteers were examined using MRE and ARFI quantification. Additionally, patients were examined with 2D-SWE.

RESULTS

A high correlation is evident for the shear wave speed (SWS) determined with different elastography methods in AATD patients: 2D-SWE/MRE, ARFI quantification/2D-SWE, and ARFI quantification/MRE (R = 0.8587, 0.7425, and 0.6914, respectively; P≤0.0089). Four AATD patients with pathologically increased SWS were consistently identified with all three methods-MRE, ARFI quantification, and 2D-SWE.

CONCLUSION

The high correlation and consistent identification of patients with pathologically increased SWS using MRE, ARFI quantification, and 2D-SWE suggest that elastography has the potential to become a suitable imaging tool for the assessment of AATD-related liver fibrosis. These promising results provide motivation for further investigation of non-invasive assessment of AATD-related liver fibrosis using elastography.

Acoustic radiation force impulse (ARFI) elastography in a cohort of alpha-1 antitrypsin-deficient individuals and healthy volunteers

Background

Acoustic radiation force impulse (ARFI) elastography has been used to assess liver stiffness non-invasively. However, its usefulness in alpha-1 antitripsin-deficient (AATD) individuals is unknown.

Purpose

To assess if liver fibrosis is present in a cohort of AATD individuals using ARFI elastography.

Material and Methods

Eighty-three participants aged 38–39 years, except for two who were aged 40 years, underwent ultrasound elastography of the liver with ARFI technique. Twenty-nine were homozygote ZZ genotype, PiZZ (14 men, 15 women); 12 were SZ genotype, Pi SZ (8 men, 4 women), and 42 were healthy volunteers, PiMM (16 men, 26 women). Three specific liver anatomical regions were examined: segments 2/3 (left lobe) in the subcostal plane, and 5/6 and 7/8 (right lobe) in the intercostal space. In each region, three measurements were registered.

Results

There was no statistically significant difference between ARFI-median in the AATD group and the control group (P value = 0.877) and neither between AATD groups (PiZZ and PiSZ) with a P value = 0.259. The ARFI-median was lower in the right liver lobe than in the left lobe in all groups and the difference between both lobes was statistically significant (P = 0.001). No statistically significant difference was found in ARFI-median of the right liver lobe between the AATD group and the control group (P = 0.759), nor between the AATD group (P = 0.384). No gender difference was found in ARFI-median.

Conclusions

ARFI values in AATD individuals aged 38–39 years showed no difference compare to healthy participants.

Viral eradication reduces both liver stiffness and steatosis in patients with chronic hepatitis C virus infection who received direct-acting anti-viral therapy

BACKGROUND

Whether direct-acting anti-viral therapy can reduce liver fibrosis and steatosis in patients with chronic hepatitis C virus (HCV) infection is unclear.

AIMS

To evaluate changes in liver stiffness and steatosis in patients with HCV who received direct-acting anti-viral therapy and achieved sustained virological response (SVR).

METHODS

A total of 198 patients infected with HCV genotype 1 or 2 who achieved SVR after direct-acting anti-viral therapy were analysed. Liver stiffness as evaluated by magnetic resonance elastography, steatosis as evaluated by magnetic resonance imaging-determined proton density fat fraction (PDFF), insulin resistance, and laboratory data were assessed before treatment (baseline) and at 24 weeks after the end of treatment (SVR24).

RESULTS

Alanine aminotransferase and homeostatic model assessment-insulin resistance levels decreased significantly from baseline to SVR24. Conversely, platelet count, which is inversely associated with liver fibrosis, increased significantly from baseline to SVR24. In patients with high triglyceride levels (≥150 mg/dL), triglyceride levels significantly decreased from baseline to SVR24 (P = 0.004). The median (interquartile range) liver stiffness values at baseline and SVR24 were 3.10 (2.70-4.18) kPa and 2.80 (2.40-3.77) kPa respectively (P < 0.001). The PDFF values at baseline and SVR 24 were 2.4 (1.7-3.4)% and 1.9 (1.3-2.8)% respectively (P < 0.001). In addition, 68% (19/28) of patients with fatty liver at baseline (PDFF ≥5.2%; n = 28) no longer had fatty liver (PDFF <5.2%) at SVR24.

CONCLUSION

Viral eradication reduces both liver stiffness and steatosis in patients with chronic HCV who received direct-acting anti-viral therapy (UMIN000017020).

Correlating liver stiffness with disease severity scoring system (DS3) values in Gaucher disease type 1 (GD1) patients

Gaucher disease (GD) is an autosomal-recessive lysosomal storage disease caused by a deficiency of the enzyme, glucocerebrocidase, resulting in accumulation of lipid-laden storage cells in multiple organs such as bone marrow, liver, spleen, and lungs. Type 1 Gaucher disease is the most common form of this condition in which the brain and spinal cord (the central nervous system) are not affected. The Gaucher disease severity scoring system (GD-DS3) is typically used to assess disease severity accounting for skeletal, hematologic, and visceral disease. In addition to being time consuming for the clinician to calculate the scores, some of the assessments are subjective and may falsely increase or decrease disease severity. The purpose of this study was to determine if there is a correlation between liver stiffness values obtained from MR elastography (MRE) and the GD-DS3 score. An IRB approved, HIPAA compliant retrospective study was performed. All patients with type 1 GD imaged with MRE between 2011 and 2016 were included in this study. Clinical and imaging data was collected. Two pediatric radiologists analyzed MR images from abdomen and thigh studies independently to determine bone marrow involvement using a semi-quantitative scoring system with one reviewer analyzing a subset of studies to determine inter-observer reliability. The collected data was used to calculate a GD-DS3 score for all patients. GD-DS3 scores were compared with liver MRE stiffness values. Clinical MRE scores were plotted against GD-DS3 severity scores for 31 patients (15 males, 16 females; median age 27years, age range: 4-67years). The median GD-DS3 score was 4 (range: 1-10.1) and median MRE value was 2.43kPa (range: 1.30-5.20kPa). A significant positive correlation was found between MRE and GD-DS3 scores; Pearson's correlation coefficient value of r=0.47, p<0.001 for all scores, r=0.68, p<0.001 for complete scores and r=0.46, p<0.07 for incomplete scores. The inter-observer variation of bone marrow burden showed only fair agreement with a Kappa coefficient of 0.26. There is a significant positive correlation between increasing liver stiffness and increasing composite GD-DS3 scores. This supports the use of MRE, a non-invasive reproducible quantitative test, as both an additional assessment and independent marker for monitoring disease severity and progression in GD.

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.