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Abreu N, Pereira VM, Pestana M, Jasmins L. Future Perspectives in the Diagnosis and Treatment of Liver Disease Associated with Alpha-1 Antitrypsin Deficiency. GE PORTUGUESE JOURNAL OF GASTROENTEROLOGY 2023; 30:327-335. [PMID: 37868641 PMCID: PMC10586215 DOI: 10.1159/000528809] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Accepted: 11/15/2022] [Indexed: 10/24/2023]
Abstract
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.
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Affiliation(s)
- Nélia Abreu
- Department of Gastroenterology, Hospital Central Do Funchal, Madeira, Portugal
| | - Vítor Magno Pereira
- Department of Gastroenterology, Hospital Central Do Funchal, Madeira, Portugal
| | - Madalena Pestana
- Department of Gastroenterology, Hospital Central Do Funchal, Madeira, Portugal
| | - Luís Jasmins
- Department of Gastroenterology, Hospital Central Do Funchal, Madeira, Portugal
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Strnad P, San Martin J. RNAi therapeutics for diseases involving protein aggregation: fazirsiran for alpha-1 antitrypsin deficiency-associated liver disease. Expert Opin Investig Drugs 2023; 32:571-581. [PMID: 37470509 DOI: 10.1080/13543784.2023.2239707] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Revised: 06/23/2023] [Accepted: 07/19/2023] [Indexed: 07/21/2023]
Abstract
INTRODUCTION Therapeutic agents that prevent protein misfolding or promote protein clearance are being studied to treat proteotoxic diseases. Among them, alpha-1 antitrypsin deficiency (AATD) is caused by mutations in the alpha-1 antitrypsin (SERPINA1) gene. Fazirsiran is a small interfering RNA (siRNA) that is intended to address the underlying cause of liver disease associated with AATD through the RNA interference (RNAi) mechanism. AREAS COVERED This article describes the role of misfolded proteins and protein aggregates in disease and options for therapeutic approaches. The RNAi mechanism is discussed, along with how the siRNA therapeutic fazirsiran for the treatment of AATD was developed. We also describe the implications of siRNA therapeutics in extrahepatic diseases. EXPERT OPINION Using RNAi as a therapeutic approach is well suited to treat disease in conditions where an excess of a protein or the effect of an abnormal mutated protein causes disease. The results observed for the first few siRNA therapeutics that were approved or are in development provide an important promise for the development of future drugs that can address such conditions in a specific and targeted way. Current developments should enable the use of RNAi therapeutics outside the liver, where there are many more possible diseases to address.
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Affiliation(s)
- Pavel Strnad
- Department of Internal Medicine III, University Hospital RWTH (Rheinisch-Westfälisch Technische Hochschule) Aachen, Aachen, Germany
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Association of Alpha-1 Antitrypsin Pi*Z Allele Frequency and Progressive Liver Fibrosis in Two Chronic Hepatitis C Cohorts. J Clin Med 2022; 12:jcm12010253. [PMID: 36615054 PMCID: PMC9821389 DOI: 10.3390/jcm12010253] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Revised: 12/13/2022] [Accepted: 12/27/2022] [Indexed: 12/31/2022] Open
Abstract
(1) Background: The inherited alpha-1 antitrypsin (A1AT) deficiency variant 'Pi*Z' emerged as a genetic modifier of chronic liver disease. Controversial data exist on the relevance of heterozygous Pi*Z carriage ('Pi*MZ' genotype) as an additional risk factor in patients with chronic viral hepatitis C to develop progressive liver fibrosis. (2) Methods: Two prospectively recruited cohorts totaling 572 patients with therapy-naïve chronic viral hepatitis C (HCV) were analyzed. The Frankfurt cohort included 337 patients and a second cohort from Leipzig included 235 patients. The stage of liver fibrosis was assessed by liver biopsy, AST-to-platelet ratio index (APRI) score and Fibrosis-4 (FIB-4) score (Frankfurt) as well as liver stiffness measurement (LSM) via transient elastography (Leipzig). All patients were genotyped for the Pi*Z variant (rs28929474) of the SERPINA1 gene. (3) Results: In the Frankfurt cohort, 16/337 (4.7%) patients carried the heterozygous Pi*Z allele while 10/235 (4.3%) in the Leipzig cohort were Pi*Z carriers. In both cohorts, there was no higher proportion of Pi*Z heterozygosity in patients with cirrhosis compared to patients without cirrhosis or patients with cirrhosis vs. no liver fibrosis. Accordingly, Pi*Z frequency was not different in histological or serological stages of liver fibrosis (F0-F4) and showed no clear association with LSM. (4) Conclusions: Evaluation in two representative HCV cohorts does not indicate Pi*Z heterozygosity as a clinically relevant disease modifier in chronic HCV infection. However, validation in even larger cohorts with longitudinal follow-up is warranted.
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Meng L, Treem W, Heap GA, Chen J. A stacking ensemble machine learning model to predict alpha-1 antitrypsin deficiency-associated liver disease clinical outcomes based on UK Biobank data. Sci Rep 2022; 12:17001. [PMID: 36220873 PMCID: PMC9554039 DOI: 10.1038/s41598-022-21389-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2022] [Accepted: 09/27/2022] [Indexed: 12/29/2022] Open
Abstract
Alpha-1 antitrypsin deficiency associated liver disease (AATD-LD) is a rare genetic disorder and not well-recognized. Predicting the clinical outcomes of AATD-LD and defining patients more likely to progress to advanced liver disease are crucial for better understanding AATD-LD progression and promoting timely medical intervention. We aimed to develop a tailored machine learning (ML) model to predict the disease progression of AATD-LD. This analysis was conducted through a stacking ensemble learning model by combining five different ML algorithms with 58 predictor variables using nested five-fold cross-validation with repetitions based on the UK Biobank data. Performance of the model was assessed through prediction accuracy, area under the receiver operating characteristic (AUROC), and area under the precision-recall curve (AUPRC). The importance of predictor contributions was evaluated through a feature importance permutation method. The proposed stacking ensemble ML model showed clinically meaningful accuracy and appeared superior to any single ML algorithms in the ensemble, e.g., the AUROC for AATD-LD was 68.1%, 75.9%, 91.2%, and 67.7% for all-cause mortality, liver-related death, liver transplant, and all-cause mortality or liver transplant, respectively. This work supports the use of ML to address the unanswered clinical questions with clinically meaningful accuracy using real-world data.
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Affiliation(s)
- Linxi Meng
- Florida State University, Tallahassee, USA
| | - Will Treem
- Takeda Development Center Americas, Inc., Cambridge, MA, USA
| | - Graham A Heap
- Takeda Development Center Americas, Inc., Cambridge, MA, USA
| | - Jingjing Chen
- Takeda Development Center Americas, Inc., Cambridge, MA, USA.
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Patel D, Teckman J. Liver disease with unknown etiology - have you ruled out alpha-1 antitrypsin deficiency? Ther Adv Chronic Dis 2021; 12_suppl:2040622321995684. [PMID: 34408828 PMCID: PMC8367207 DOI: 10.1177/2040622321995684] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Accepted: 01/12/2021] [Indexed: 01/13/2023] Open
Abstract
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.
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Affiliation(s)
- Dhiren Patel
- Department of Pediatrics, Division of Gastroenterology, Hepatology and Nutrition, St Louis University School of Medicine, St Louis, MO, USA
| | - Jeffrey Teckman
- Department of Pediatrics and Department of Biochemistry and Molecular Biology, St Louis University School of Medicine, St Louis, MO, USA
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Burbaum B, Fromme M, Strnad P. [Alpha-1 antitrypsin deficiency: cause and cofactor for liver disease]. Dtsch Med Wochenschr 2021; 146:714-718. [PMID: 34062584 DOI: 10.1055/a-1277-9066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Alpha-1-antitrypsin deficiency (AATD) is a genetic disorder arising due to mutation in alpha1-antitrypsin (AAT). AAT mutations interfere with the AAT production/secretion, cause decreased AAT serum levels and accumulation of AAT in the liver. The excess AAT leads to a proteotoxic liver disease, while the lack of AAT in systemic circulation predisposes to lung injury. While AATD related lung disease is well understood, liver disease needs further awareness. Non-invasive liver stiffness measurement constitutes a useful method to estimate the extent of liver fibrosis. Significant liver fibrosis occurs in 20-35 % of individuals with the classic, severe genotype Pi*ZZ. Genotype Pi*SZ, also known as the compound heterozygous form, confers an increased risk of both liver fibrosis and liver neoplasia. Even the heterozygous genotype Pi*MZ increases the odds of fibrosis in presence of further risk factors such as obesity, male sex, metabolic syndrome and diabetes mellitus. In individuals with non-alcoholic fatty liver disease or alcohol misuse it promotes the development of liver cirrhosis. While no drug treatment exists for AATD-related liver disease, there are several compounds in clinical phase II/III-trials. These either silence the AAT production via siRNA or facilitate the secretion of AAT from the liver due to an improved folding.
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Affiliation(s)
- Barbara Burbaum
- Medizinische Klinik III, Gastroenterologie, Stoffwechselerkrankungen und Intensivmedizin, Uniklinik Aachen, Aachen, Deutschland
| | - Malin Fromme
- Medizinische Klinik III, Gastroenterologie, Stoffwechselerkrankungen und Intensivmedizin, Uniklinik Aachen, Aachen, Deutschland
| | - Pavel Strnad
- Medizinische Klinik III, Gastroenterologie, Stoffwechselerkrankungen und Intensivmedizin, Uniklinik Aachen, Aachen, Deutschland
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Pons M, Núñez A, Esquinas C, Torres-Durán M, Rodríguez-Hermosa JL, Calle M, Tubio-Pérez R, Belmonte I, Rodríguez-Frías F, Rodríguez E, Genescà J, Miravitlles M, Barrecheguren M. Utility of Transient Elastography for the Screening of Liver Disease in Patients with Alpha1-Antitrypsin Deficiency. J Clin Med 2021; 10:jcm10081724. [PMID: 33923569 PMCID: PMC8073267 DOI: 10.3390/jcm10081724] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Revised: 04/12/2021] [Accepted: 04/13/2021] [Indexed: 02/07/2023] Open
Abstract
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.
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Affiliation(s)
- Mònica Pons
- Liver Unit, Department of Internal Medicine, Hospital Universitari Vall d’Hebron, Vall d’Hebron Institut de Recerca (VHIR), Vall d’Hebron Barcelona Hospital Campus, 08035 Barcelona, Spain; (M.P.); (J.G.)
| | - Alexa Núñez
- Pneumology Department, Hospital Universitari Vall d’Hebron/Vall d’Hebron Institut de Recerca (VHIR), Vall d’Hebron Barcelona Hospital Campus, 08035 Barcelona, Spain; (A.N.); (C.E.); (I.B.); (E.R.); (M.B.)
- Department of Medicine, Universitat Autònoma de Barcelona, 08193 Barcelona, Spain
| | - Cristina Esquinas
- Pneumology Department, Hospital Universitari Vall d’Hebron/Vall d’Hebron Institut de Recerca (VHIR), Vall d’Hebron Barcelona Hospital Campus, 08035 Barcelona, Spain; (A.N.); (C.E.); (I.B.); (E.R.); (M.B.)
- Department of Medicine, Universitat Autònoma de Barcelona, 08193 Barcelona, Spain
| | - María Torres-Durán
- Pneumology Department, University Hospital Complex of Vigo, Instituto de Investigación Biomédica Galicia Sur, 36213 Vigo, Spain; (M.T.-D.); (R.T.-P.)
| | - Juan Luis Rodríguez-Hermosa
- Pneumology Department, Instituto de Investigación Sanitaria del Hospital Clínico San Carlos (IdISSC), Hospital Clínico de San Carlos, Departamento de Medicina, Facultad de Medicina, Universidad Complutense de Madrid, 28040 Madrid, Spain; (J.L.R.-H.); (M.C.)
| | - Myriam Calle
- Pneumology Department, Instituto de Investigación Sanitaria del Hospital Clínico San Carlos (IdISSC), Hospital Clínico de San Carlos, Departamento de Medicina, Facultad de Medicina, Universidad Complutense de Madrid, 28040 Madrid, Spain; (J.L.R.-H.); (M.C.)
| | - Ramón Tubio-Pérez
- Pneumology Department, University Hospital Complex of Vigo, Instituto de Investigación Biomédica Galicia Sur, 36213 Vigo, Spain; (M.T.-D.); (R.T.-P.)
| | - Irene Belmonte
- Pneumology Department, Hospital Universitari Vall d’Hebron/Vall d’Hebron Institut de Recerca (VHIR), Vall d’Hebron Barcelona Hospital Campus, 08035 Barcelona, Spain; (A.N.); (C.E.); (I.B.); (E.R.); (M.B.)
| | - Francisco Rodríguez-Frías
- Department of Clinical Biochemistry, Hospital Universitari Vall d’Hebron, Vall d’Hebron Barcelona Hospital Campus, 08035 Barcelona, Spain;
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBEREHD), 28029 Madrid, Spain
| | - Esther Rodríguez
- Pneumology Department, Hospital Universitari Vall d’Hebron/Vall d’Hebron Institut de Recerca (VHIR), Vall d’Hebron Barcelona Hospital Campus, 08035 Barcelona, Spain; (A.N.); (C.E.); (I.B.); (E.R.); (M.B.)
| | - Joan Genescà
- Liver Unit, Department of Internal Medicine, Hospital Universitari Vall d’Hebron, Vall d’Hebron Institut de Recerca (VHIR), Vall d’Hebron Barcelona Hospital Campus, 08035 Barcelona, Spain; (M.P.); (J.G.)
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBEREHD), 28029 Madrid, Spain
| | - Marc Miravitlles
- Pneumology Department, Hospital Universitari Vall d’Hebron/Vall d’Hebron Institut de Recerca (VHIR), Vall d’Hebron Barcelona Hospital Campus, 08035 Barcelona, Spain; (A.N.); (C.E.); (I.B.); (E.R.); (M.B.)
- Department of Medicine, Universitat Autònoma de Barcelona, 08193 Barcelona, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Respiratorias (CIBERES), 28029 Madrid, Spain
- Correspondence:
| | - Miriam Barrecheguren
- Pneumology Department, Hospital Universitari Vall d’Hebron/Vall d’Hebron Institut de Recerca (VHIR), Vall d’Hebron Barcelona Hospital Campus, 08035 Barcelona, Spain; (A.N.); (C.E.); (I.B.); (E.R.); (M.B.)
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