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Rieman-Klingler MC, Jung J, Tesfai K, Loomba R, Non AL. Integrating genetic and socioeconomic data to predict the progression of nonalcoholic fatty liver disease. AMERICAN JOURNAL OF BIOLOGICAL ANTHROPOLOGY 2024; 184:e24979. [PMID: 38778456 DOI: 10.1002/ajpa.24979] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Revised: 04/25/2024] [Accepted: 05/08/2024] [Indexed: 05/25/2024]
Abstract
OBJECTIVES Nonalcoholic fatty liver disease (NAFLD) is the leading cause of chronic liver disease globally, with an estimated prevalence exceeding 25%. Variants in the PNPLA3 and HSD17B13 genes have been a focus of investigations surrounding the etiology and progression of NAFLD and are believed to contribute to a greater burden of disease experienced by Hispanic Americans. However, little is known about socioeconomic factors influencing NAFLD progression or its increased prevalence among Hispanics. MATERIALS AND METHODS We cross-sectionally analyzed 264 patients to assess the role of genetic and socioeconomic variables in the development of advanced liver fibrosis in individuals at risk for NAFLD. RESULTS Adjusting for age, sex, body mass index, and PNPLA3 genotype, lacking a college degree was associated with 3.3 times higher odds of advanced fibrosis (95% confidence interval [CI]: 1.21-8.76, p = 0.019), an effect comparable to that of possessing the major PNPLA3 risk variant. Notably, the effect of PNPLA3 genotype on advanced fibrosis was attenuated to nonsignificance following adjustment for education and other socioeconomic markers. The effect of the protective HSD17B13 variant, moreover, diminished after adjustment for education (odds ratio [OR]: 0.39 [95% CI: 0.13-1.16, p = 0.092]), while lower education continued to predict advanced fibrosis following multivariable adjustment with an OR of 8.0 (95% CI: 1.91-33.86, p = 0.005). DISCUSSION Adjusting for education attenuated the effects of genotype and Hispanic ethnicity on liver fibrosis, suggesting that social factors-rather than genes or ethnicity-may be driving disease severity within some populations. Findings reveal the importance of including socioenvironmental controls when considering the role of genetics or ethnicity in complex disease.
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Affiliation(s)
- Maria C Rieman-Klingler
- Department of Anthropology, University of California, San Diego, La Jolla, California, USA
- School of Medicine, University of California, San Diego, La Jolla, California, USA
- Medical Scientist Training (MD/PhD) Program, University of California, San Diego, La Jolla, California, USA
| | - Jinho Jung
- NAFLD Research Center, Division of Gastroenterology and Hepatology, Department of Medicine, University of California, San Diego, La Jolla, California, USA
| | - Kaleb Tesfai
- NAFLD Research Center, Division of Gastroenterology and Hepatology, Department of Medicine, University of California, San Diego, La Jolla, California, USA
| | - Rohit Loomba
- NAFLD Research Center, Division of Gastroenterology and Hepatology, Department of Medicine, University of California, San Diego, La Jolla, California, USA
- Division of Epidemiology, Department of Family Medicine and Public Health, University of California, San Diego, La Jolla, California, USA
| | - Amy L Non
- Department of Anthropology, University of California, San Diego, La Jolla, California, USA
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Wakabayashi SI, Tamaki N, Kimura T, Umemura T, Kurosaki M, Izumi N. Natural history of lean and non-lean metabolic dysfunction-associated steatotic liver disease. J Gastroenterol 2024; 59:494-503. [PMID: 38570344 DOI: 10.1007/s00535-024-02093-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Accepted: 02/29/2024] [Indexed: 04/05/2024]
Abstract
BACKGROUND Conflicting evidence regarding the prognosis of lean metabolic dysfunction-associated steatotic liver disease (MASLD) has raised substantial questions. AIM This study aimed to elucidate the prognosis of lean MASLD by conducting a comprehensive analysis of a vast Asian cohort. METHODS This study used a nationwide, population-based database and analyzed 2.9 million patients. The primary endpoints were liver-related events (LREs) and cardiovascular events (CVEs) in patients with lean MASLD, non-lean MASLD, and normal liver control groups. RESULTS The median observation period was 4.2 years. The 5-year incidence values of LREs in the lean MASLD, non-lean MASLD, and normal liver control groups were 0.065%, 0.039%, and 0.006%, respectively. The LRE risk of lean MASLD was significantly higher than that of normal liver control (adjusted hazard ratio [aHR]: 5.94, 95% confidence interval [CI]: 3.95-8.92) but comparable to that of non-lean MASLD (aHR: 1.35, 95% CI: 0.87-2.08). By contrast, for CVEs, the non-lean MASLD group exhibited a higher 5-year cumulative incidence rate (0.779%) than the lean MASLD (0.600%) and normal liver control (0.254%) groups. The lean MASLD group had a reduced risk of CVEs compared with the non-lean MASLD group (aHR, 0.73; 95% CI: 0.64-0.84), and comparable risk of CVEs to the normal liver control group (aHR, 0.99; 95% CI: 0.88-1.12). CONCLUSION Lean MASLD exhibits a similar LRE risk and a lower CVE risk to non-lean MASLD. Therefore, follow-up and treatment strategies should be tailored to the specific MASLD condition.
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Affiliation(s)
- Shun-Ichi Wakabayashi
- Division of Gastroenterology, Department of Medicine, Shinshu University School of Medicine, Nagano, Japan
| | - Nobuharu Tamaki
- Department of Gastroenterology and Hepatology, Musashino Red Cross Hospital, 1-26-1 Kyonan-Cho, Musashino-Shi, Tokyo, 180-8610, Japan
| | - Takefumi Kimura
- Division of Gastroenterology, Department of Medicine, Shinshu University School of Medicine, Nagano, Japan
| | - Takeji Umemura
- Division of Gastroenterology, Department of Medicine, Shinshu University School of Medicine, Nagano, Japan
| | - Masayuki Kurosaki
- Department of Gastroenterology and Hepatology, Musashino Red Cross Hospital, 1-26-1 Kyonan-Cho, Musashino-Shi, Tokyo, 180-8610, Japan.
| | - Namiki Izumi
- Department of Gastroenterology and Hepatology, Musashino Red Cross Hospital, 1-26-1 Kyonan-Cho, Musashino-Shi, Tokyo, 180-8610, Japan
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Rosso C, Caviglia GP, Birolo G, Armandi A, Pennisi G, Pelusi S, Younes R, Liguori A, Perez-Diaz-Del-Campo N, Nicolosi A, Govaere O, Castelnuovo G, Olivero A, Abate ML, Ribaldone DG, Fariselli P, Valenti L, Miele L, Petta S, Romero-Gomez M, Anstee QM, Bugianesi E. Impact of PNPLA3 rs738409 Polymorphism on the Development of Liver-Related Events in Patients With Nonalcoholic Fatty Liver Disease. Clin Gastroenterol Hepatol 2023; 21:3314-3321.e3. [PMID: 37149016 DOI: 10.1016/j.cgh.2023.04.024] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Revised: 04/12/2023] [Accepted: 04/20/2023] [Indexed: 05/08/2023]
Abstract
BACKGROUND AND AIMS Nonalcoholic fatty liver disease (NAFLD) is a complex disease, resulting from the interplay between environmental determinants and genetic variations. Single nucleotide polymorphism rs738409 C>G in the PNPLA3 gene is associated with hepatic fibrosis and with higher risk of developing hepatocellular carcinoma. Here, we analyzed a longitudinal cohort of biopsy-proven NAFLD subjects with the aim to identify individuals in whom genetics may have a stronger impact on disease progression. METHODS We retrospectively analyzed 756 consecutive, prospectively enrolled biopsy-proven NAFLD subjects from Italy, United Kingdom, and Spain who were followed for a median of 84 months (interquartile range, 65-109 months). We stratified the study cohort according to sex, body mass index (BMI) ≥30 kg/m2) and age (≥50 years). Liver-related events (hepatic decompensation, hepatic encephalopathy, esophageal variceal bleeding, and hepatocellular carcinoma) were recorded during the follow-up and the log-rank test was used to compare groups. RESULTS Overall, the median age was 48 years and most individuals were men (64.7%). The PNPLA3 rs738409 genotype was CC in 235 (31.1%), CG in 328 (43.4%), and GG in 193 (25.5%) patients. At univariate analysis, the PNPLA3 GG risk genotype was associated with female sex and inversely related to BMI (odds ratio, 1.6; 95% confidence interval, 1.1-2.2; P = .006; and odds ratio, 0.97; 95% confidence interval, 0.94-0.99; P = .043, respectively). Specifically, PNPLA3 GG risk homozygosis was more prevalent in female vs male individuals (31.5% vs 22.3%; P = .006) and in nonobese compared with obese NAFLD subjects (50.0% vs 44.2%; P = .011). Following stratification for age, sex, and BMI, we observed an increased incidence of liver-related events in the subgroup of nonobese women older than 50 years of age carrying the PNPLA3 GG risk genotype (log-rank test, P = .0047). CONCLUSIONS Nonobese female patients with NAFLD 50 years of age and older, and carrying the PNPLA3 GG risk genotype, are at higher risk of developing liver-related events compared with those with the wild-type allele (CC/CG). This finding may have implications in clinical practice for risk stratification and personalized medicine.
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Affiliation(s)
- Chiara Rosso
- Division of Gastroenterology and Hepatology, Department of Medical Sciences, University of Turin, Turin, Italy
| | - Gian Paolo Caviglia
- Division of Gastroenterology and Hepatology, Department of Medical Sciences, University of Turin, Turin, Italy
| | - Giovanni Birolo
- Division of Gastroenterology and Hepatology, Department of Medical Sciences, University of Turin, Turin, Italy
| | - Angelo Armandi
- Division of Gastroenterology and Hepatology, Department of Medical Sciences, University of Turin, Turin, Italy; Metabolic Liver Disease Research Program, I. Department of Medicine, University Medical Center of the Johannes Gutenberg-University, Mainz, Germany
| | - Grazia Pennisi
- Sezione di Gastroenterologia, PROMISE, Università di Palermo, Palermo, Italy
| | - Serena Pelusi
- Precision Medicine, Department of Transfusion Medicine, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Ramy Younes
- Boehringer Ingelheim International, GmbH, Ingelheim, Germany
| | - Antonio Liguori
- Dipartimento Universitario Medicina e Chirurgia Traslazionale, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Nuria Perez-Diaz-Del-Campo
- Division of Gastroenterology and Hepatology, Department of Medical Sciences, University of Turin, Turin, Italy
| | - Aurora Nicolosi
- Division of Gastroenterology and Hepatology, Department of Medical Sciences, University of Turin, Turin, Italy
| | - Olivier Govaere
- Newcastle Liver Research Group, Translational & Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Gabriele Castelnuovo
- Division of Gastroenterology and Hepatology, Department of Medical Sciences, University of Turin, Turin, Italy
| | - Antonella Olivero
- Division of Gastroenterology and Hepatology, Department of Medical Sciences, University of Turin, Turin, Italy
| | - Maria Lorena Abate
- Division of Gastroenterology and Hepatology, Department of Medical Sciences, University of Turin, Turin, Italy
| | - Davide Giuseppe Ribaldone
- Division of Gastroenterology and Hepatology, Department of Medical Sciences, University of Turin, Turin, Italy
| | - Piero Fariselli
- Division of Gastroenterology and Hepatology, Department of Medical Sciences, University of Turin, Turin, Italy
| | - Luca Valenti
- Precision Medicine, Department of Transfusion Medicine, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy; Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy
| | - Luca Miele
- Dipartimento Universitario Medicina e Chirurgia Traslazionale, Università Cattolica del Sacro Cuore, Rome, Italy; Dipartimento di Scienze Mediche e Chirurgiche, Fondazione Policlinico Gemelli IRCCS, Rome, Italy
| | - Salvatore Petta
- Sezione di Gastroenterologia, PROMISE, Università di Palermo, Palermo, Italy
| | - Manuel Romero-Gomez
- UCM Digestive Diseases and SeLiver Group, Virgen del Rocío University Hospital, Institute of Biomedicine of Seville, University of Seville, Seville, Spain
| | - Quentin M Anstee
- Newcastle Liver Research Group, Translational & Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom; Newcastle NIHR Biomedical Research Centre, Newcastle upon Tyne Hospitals NHS Trust, Newcastle upon Tyne, United Kingdom
| | - Elisabetta Bugianesi
- Division of Gastroenterology and Hepatology, Department of Medical Sciences, University of Turin, Turin, Italy.
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Luukkonen PK, Porthan K, Ahlholm N, Rosqvist F, Dufour S, Zhang XM, Lehtimäki TE, Seppänen W, Orho-Melander M, Hodson L, Petersen KF, Shulman GI, Yki-Järvinen H. The PNPLA3 I148M variant increases ketogenesis and decreases hepatic de novo lipogenesis and mitochondrial function in humans. Cell Metab 2023; 35:1887-1896.e5. [PMID: 37909034 DOI: 10.1016/j.cmet.2023.10.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Revised: 06/26/2023] [Accepted: 10/12/2023] [Indexed: 11/02/2023]
Abstract
The PNPLA3 I148M variant is the major genetic risk factor for all stages of fatty liver disease, but the underlying pathophysiology remains unclear. We studied the effect of this variant on hepatic metabolism in homozygous carriers and non-carriers under multiple physiological conditions with state-of-the-art stable isotope techniques. After an overnight fast, carriers had higher plasma β-hydroxybutyrate concentrations and lower hepatic de novo lipogenesis (DNL) compared to non-carriers. After a mixed meal, fatty acids were channeled toward ketogenesis in carriers, which was associated with an increase in hepatic mitochondrial redox state. During a ketogenic diet, carriers manifested increased rates of intrahepatic lipolysis, increased plasma β-hydroxybutyrate concentrations, and decreased rates of hepatic mitochondrial citrate synthase flux. These studies demonstrate that homozygous PNPLA3 I148M carriers have hepatic mitochondrial dysfunction leading to reduced DNL and channeling of carbons to ketogenesis. These findings have implications for understanding why the PNPLA3 variant predisposes to progressive liver disease.
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Affiliation(s)
- Panu K Luukkonen
- Department of Medicine, Yale School of Medicine, New Haven, CT, USA; Minerva Foundation Institute for Medical Research, Helsinki, Finland; Department of Medicine, University of Helsinki and Helsinki University Hospital, Helsinki, Finland; Abdominal Center, Helsinki University Hospital, Helsinki, Finland.
| | - Kimmo Porthan
- Minerva Foundation Institute for Medical Research, Helsinki, Finland; Department of Medicine, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Noora Ahlholm
- Minerva Foundation Institute for Medical Research, Helsinki, Finland; Department of Medicine, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Fredrik Rosqvist
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford & NIHR Oxford Biomedical Research Centre, Oxford University Hospitals Foundation Trust, Oxford, UK; Department of Public Health and Caring Sciences, Clinical Nutrition and Metabolism, Uppsala University, Uppsala, Sweden
| | - Sylvie Dufour
- Department of Medicine, Yale School of Medicine, New Haven, CT, USA; Yale Diabetes Research Center, Yale School of Medicine, New Haven, CT, USA
| | - Xian-Man Zhang
- Department of Medicine, Yale School of Medicine, New Haven, CT, USA; Yale Diabetes Research Center, Yale School of Medicine, New Haven, CT, USA
| | - Tiina E Lehtimäki
- Department of Radiology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Wenla Seppänen
- Department of Radiology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Marju Orho-Melander
- Department of Clinical Sciences, Diabetes and Endocrinology, University Hospital Malmö, Lund University, Malmö, Sweden
| | - Leanne Hodson
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford & NIHR Oxford Biomedical Research Centre, Oxford University Hospitals Foundation Trust, Oxford, UK
| | - Kitt Falk Petersen
- Department of Medicine, Yale School of Medicine, New Haven, CT, USA; Yale Diabetes Research Center, Yale School of Medicine, New Haven, CT, USA
| | - Gerald I Shulman
- Department of Medicine, Yale School of Medicine, New Haven, CT, USA; Yale Diabetes Research Center, Yale School of Medicine, New Haven, CT, USA; Department of Cellular & Molecular Physiology, Yale School of Medicine, New Haven, CT, USA
| | - Hannele Yki-Järvinen
- Minerva Foundation Institute for Medical Research, Helsinki, Finland; Department of Medicine, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
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Caddeo A, Spagnuolo R, Maurotti S. MBOAT7 in liver and extrahepatic diseases. Liver Int 2023; 43:2351-2364. [PMID: 37605540 DOI: 10.1111/liv.15706] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2023] [Revised: 07/28/2023] [Accepted: 08/10/2023] [Indexed: 08/23/2023]
Abstract
MBOAT7 is a protein anchored to endomembranes by several transmembrane domains. It has a catalytic dyad involved in remodelling of phosphatidylinositol with polyunsaturated fatty acids. Genetic variants in the MBOAT7 gene have been associated with the entire spectrum of non-alcoholic fatty liver (NAFLD), recently redefined as metabolic dysfunction-associated fatty liver disease (MAFLD) and, lately, steatotic liver disease (SLD), and to an increasing number of extrahepatic conditions. In this review, we will (a) elucidate the molecular mechanisms by which MBOAT7 loss-of-function predisposes to MAFLD and neurodevelopmental disorders and (b) discuss the growing number of genetic studies linking MBOAT7 to hepatic and extrahepatic diseases. MBOAT7 complete loss of function causes severe changes in brain development resulting in several neurological manifestations. Lower MBOAT7 hepatic expression at both the mRNA and protein levels, due to missense nucleotide polymorphisms (SNPs) in the locus containing the MBOAT7 gene, affects specifically metabolic and viral diseases in the liver from simple steatosis to hepatocellular carcinoma, and potentially COVID-19 disease. This body of evidence shows that phosphatidylinositol remodelling is a key factor for human health.
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Affiliation(s)
- Andrea Caddeo
- Department of Biomedical Sciences, Unit of Oncology and Molecular Pathology, University of Cagliari, Cagliari, Italy
| | - Rocco Spagnuolo
- Department of Health Sciences, University Magna Graecia, Catanzaro, Italy
| | - Samantha Maurotti
- Department of Experimental and Clinical Medicine, Magna Graecia University, Catanzaro, Italy
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Zhang Z, Ji G, Li M. Glucokinase regulatory protein: a balancing act between glucose and lipid metabolism in NAFLD. Front Endocrinol (Lausanne) 2023; 14:1247611. [PMID: 37711901 PMCID: PMC10497960 DOI: 10.3389/fendo.2023.1247611] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Accepted: 08/14/2023] [Indexed: 09/16/2023] Open
Abstract
Non-alcoholic fatty liver disease (NAFLD) is a common liver disease worldwide, affected by both genetics and environment. Type 2 diabetes (T2D) stands as an independent environmental risk factor that precipitates the onset of hepatic steatosis and accelerates its progression to severe stages of liver damage. Furthermore, the coexistence of T2D and NAFLD magnifies the risk of cardiovascular disease synergistically. However, the association between genetic susceptibility and metabolic risk factors in NAFLD remains incompletely understood. The glucokinase regulator gene (GCKR), responsible for encoding the glucokinase regulatory protein (GKRP), acts as a regulator and protector of the glucose-metabolizing enzyme glucokinase (GK) in the liver. Two common variants (rs1260326 and rs780094) within the GCKR gene have been associated with a lower risk for T2D but a higher risk for NAFLD. Recent studies underscore that T2D presence significantly amplifies the effect of the GCKR gene, thereby increasing the risk of NASH and fibrosis in NAFLD patients. In this review, we focus on the critical roles of GKRP in T2D and NAFLD, drawing upon insights from genetic and biological studies. Notably, prior attempts at drug development targeting GK with glucokinase activators (GKAs) have shown potential risks of augmented plasma triglycerides or NAFLD. Conversely, overexpression of GKRP in diabetic rats improved glucose tolerance without causing NAFLD, suggesting the crucial regulatory role of GKRP in maintaining hepatic glucose and lipid metabolism balance. Collectively, this review sheds new light on the complex interaction between genes and environment in NAFLD, focusing on the GCKR gene. By integrating evidence from genetics, biology, and drug development, we reassess the therapeutic potential of targeting GK or GKRP for metabolic disease treatment. Emerging evidence suggests that selectively activating GK or enhancing GK-GKRP binding may represent a holistic strategy for restoring glucose and lipid metabolic balance.
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Affiliation(s)
| | | | - Meng Li
- Institute of Digestive Diseases, Longhua Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, China
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Agyapong G, Dashti F, Banini BA. Nonalcoholic liver disease: Epidemiology, risk factors, natural history, and management strategies. Ann N Y Acad Sci 2023; 1526:16-29. [PMID: 37400359 PMCID: PMC10524684 DOI: 10.1111/nyas.15012] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/05/2023]
Abstract
Nonalcoholic fatty liver disease (NAFLD) is now the most common chronic liver disease worldwide and a leading indication for liver transplantation in the United States. NAFLD encompasses a heterogeneous clinicopathologic spectrum, ranging from nonalcoholic fatty liver (NAFL) to nonalcoholic steatohepatitis, and progressive fibrosis, which can lead to end-stage liver disease including cirrhosis and hepatocellular cancer. Predictive models suggest that over 100 million adults in the United States will have NAFLD by 2030, representing over a third of the population. In this manuscript, we provide an overview of NAFLD risk factors, natural history (including hepatic and extra-hepatic outcomes), diagnosis, and current management strategies.
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Affiliation(s)
- George Agyapong
- Section of Digestive Diseases, Yale University School of Medicine, New Haven, Connecticut, USA
- Department of Medicine, Yale School of Medicine, New Haven, Connecticut, USA
| | - Farzaneh Dashti
- Section of Digestive Diseases, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Bubu A Banini
- Section of Digestive Diseases, Yale University School of Medicine, New Haven, Connecticut, USA
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Ajmera V, Loomba R. Advances in the genetics of nonalcoholic fatty liver disease. Curr Opin Gastroenterol 2023; 39:150-155. [PMID: 37144531 PMCID: PMC10167543 DOI: 10.1097/mog.0000000000000927] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
PURPOSE OF REVIEW Nonalcoholic fatty liver disease (NAFLD) is the most common cause of liver disease in the United States and has a strong heritable component. Advances in understanding the genetic underpinnings of NAFLD have revealed important insights into NAFLD pathogenesis, prognosis, and potential therapeutic targets. The purpose of this review is to summarize data on common and rare variants associated with NAFLD, combining risk variants into polygenic scores to predict NAFLD and cirrhosis as well as emerging evidence on using gene silencing as a novel therapeutic target in NAFLD. RECENT FINDINGS Protective variants in HSD17B13, MARC1 and CIDEB have been identified and a confer 10-50% lower risk of cirrhosis. Together, these as well as other NAFLD risk variants, including those in PNPLA3 and TM6SF2, can be combined to create polygenic risk scores associated with liver fat, cirrhosis, and hepatocellular carcinoma. Genomic analysis of extreme phenotypes including patients with lean NAFLD without visceral adiposity may uncover rare monogenic disorders with pathogenic and therapeutic implications and gene silencing strategies targeting HSD17B13 and PNPLA3 are being evaluated in early phase human studies as treatments for NAFLD. SUMMARY Advances in our understanding of the genetics of NAFLD will enable clinical risk stratification and yield potential therapeutic targets.
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Affiliation(s)
- Veeral Ajmera
- NAFLD Research Center, Division of Gastroenterology. University of California at San Diego, La Jolla, CA, USA
- Division of Gastroenterology and Hepatology, University of California at San Diego, La Jolla, CA, USA
| | - Rohit Loomba
- NAFLD Research Center, Division of Gastroenterology. University of California at San Diego, La Jolla, CA, USA
- Division of Gastroenterology and Hepatology, University of California at San Diego, La Jolla, CA, USA
- School of Public Health, University of California at San Diego, La Jolla, CA, USA
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Ajmera V, Wang N, Xu H, Liu CT, Long MT. Longitudinal association between overweight years, polygenic risk and NAFLD, significant fibrosis and cirrhosis. Aliment Pharmacol Ther 2023; 57:1143-1150. [PMID: 36924053 PMCID: PMC10178778 DOI: 10.1111/apt.17452] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Revised: 11/06/2023] [Accepted: 02/23/2023] [Indexed: 03/18/2023]
Abstract
BACKGROUND Adiposity amplifies the genetic risk of non-alcoholic fatty liver disease (NAFLD). AIM We evaluated the association between overweight-years, a cumulative exposure based on the product of the duration and severity of excess body weight (body mass index (BMI) ≥ 25 kg/m2 ), and genetic risk on liver fat and fibrosis. METHODS This is a longitudinal analysis derived from a prospective cohort of adults in the Framingham Heart Study who underwent genotyping and vibration-controlled-transient-elastography with controlled attenuation parameter. Univariable and multivariable linear and logistic regression analyses were used to assess the association between overweight-years and liver fat and fibrosis. The association between genetic variants of liver fat (PNPLA3, TM6SF2, GCKR) and fibrosis (PNPLA3, TM6SF2, HSD17B13) was also assessed using a polygenic risk score. RESULTS Our sample included 2478 participants (54% women) with mean age and BMI of 40 (±8.5) years and 26.5(±5.1) kg/m2 , respectively. The mean follow-up was 14(±0.9) years, and each participant underwent three study visits. The prevalence of NAFLD was 28.3% (n = 700), and 207 (8.4%) had clinically significant fibrosis. In age-, sex- and diabetes-adjusted multivariable analyses, overweight-years (per SD) had a strong association with NAFLD (aOR 3.53 [95% CI: 3.10-4.02], p < 0.001), clinically significant fibrosis (aOR 1.60 [95% CI: 1.40-1.84], p < 0.001) and cirrhosis (aOR 1.81 [95% CI: 1.38-2.37], p < 0.001). High-polygenic risk was significantly associated with liver fat and clinically significant fibrosis (p < 0.05). CONCLUSION Overweight-years is strongly associated with NAFLD and clinically significant fibrosis and combined with polygenic risk may assist in defining the trajectory of NAFLD.
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Affiliation(s)
- Veeral Ajmera
- NAFLD Research Center, Division of Gastroenterology, University of California at San Diego, La Jolla, California, USA
- Division of Gastroenterology, University of California at San Diego, La Jolla, California, USA
| | - Na Wang
- Biostatistics and Epidemiology Data Analytics Center, Boston University School of Public Health, Boston, Massachusetts, USA
| | - Hanfei Xu
- Department of Biostatistics, Boston University School of Public Health, Boston, Massachusetts, USA
| | - Ching-Ti Liu
- Department of Biostatistics, Boston University School of Public Health, Boston, Massachusetts, USA
| | - Michelle T. Long
- Section of Gastroenterology, Boston Medical Center, Boston University School of Medicine, Boston, Massachusetts, USA
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Ajmera V. Editorial: "being normal weight each day keeps NAFLD and fibrosis away"-the importance of reducing cumulative exposure to overweight. Authors' reply. Aliment Pharmacol Ther 2023; 57:1168-1169. [PMID: 37094321 DOI: 10.1111/apt.17478] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 04/26/2023]
Affiliation(s)
- Veeral Ajmera
- NAFLD Research Center, Division of Gastroenterology, University of California at San Diego, La Jolla, California, USA
- Division of Gastroenterology and Hepatology, University of California at San Diego, La Jolla, California, USA
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Zheng M, Huang DQ, Konkwo C, Agrawal S, Khera AV, Loomba R, Vilarinho S, Ajmera V. Genomic analysis of lean individuals with NAFLD identifies monogenic disorders in a prospective cohort study. JHEP Rep 2023; 5:100692. [PMID: 36937991 PMCID: PMC10017416 DOI: 10.1016/j.jhepr.2023.100692] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 01/13/2023] [Accepted: 01/17/2023] [Indexed: 02/05/2023] Open
Abstract
Background & Aims Lean patients with non-alcoholic fatty liver disease (NAFLD) represent 10-20% of the affected population and may have heterogeneous drivers of disease. We have recently proposed the evaluation of patients with lean NAFLD without visceral adiposity for rare monogenic drivers of disease. Here, we aimed to validate this framework in a well-characterised cohort of patients with biopsy-proven NAFLD by performing whole exome sequencing. Methods This prospective study included 124 patients with biopsy-proven NAFLD and paired liver biopsies who underwent standardised research visits including advanced magnetic resonance imaging (MRI) assessment of liver fat and stiffness. Results Six patients with lean NAFLD were identified and underwent whole exome sequencing. Two lean patients (33%) were identified to have monogenic disorders. The lean patients with monogenic disorders had similar age, and anthropometric and MRI characteristics to lean patients without a monogenic disorder. Patient 1 harbours a rare homozygous pathogenic mutation in ALDOB (aldolase B) and was diagnosed with hereditary fructose intolerance. Patient 2 harbours a rare heterozygous mutation in apolipoprotein B (APOB). The pathogenicity of this APOB variant (p.Val1856CysfsTer2) was further validated in the UK Biobank and associated with lower circulating APOB levels (beta = -0.51 g/L, 95% CI -0.65 to -0.36 g/L, p = 1.4 × 10-11) and higher liver fat on MRI (beta = +10.4%, 95% CI 4.3-16.5%, p = 8.8 × 10-4). Hence, patient 2 was diagnosed with heterozygous familial hypobetalipoproteinaemia. Conclusions In this cohort of well-characterised patients with lean NAFLD without visceral adiposity, 33% (2/6) had rare monogenic drivers of disease, highlighting the importance of genomic analysis in this NAFLD subtype. Impact and Implications Although most people with non-alcoholic fatty liver disease (NAFLD) are overweight or obese, a subset are lean and may have unique genetic mutations that cause their fatty liver disease. We show that 33% of study participants with NAFLD who were lean harboured unique mutations that cause their fatty liver, and that these mutations had effects beyond the liver. This study demonstrates the value of genetic assessment of NAFLD in lean individuals to identify distinct subtypes of disease.
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Key Words
- ALT, alanine aminotransferase
- APOB, apolipoprotein B
- FHBL, familial hypobetalipoproteinaemia
- LOFHC, high-confidence predicted loss-of-function
- MRE, magnetic resonance elastography
- MRI, magnetic resonance imaging
- MRI-PDFF, magnetic resonance imaging proton density fat fraction
- NAFLD
- NAFLD, non-alcoholic fatty liver disease
- Non-obese
- Rare genetic variants
- UCSD, University of California San Diego
- WES, whole exome sequencing
- Whole exome sequencing
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Affiliation(s)
- Melanie Zheng
- Departments of Internal Medicine, Section of Digestive Diseases, and of Pathology, Yale School of Medicine, New Haven, CT, USA
| | - Daniel Q. Huang
- NAFLD Research Center, Division of Gastroenterology, University of California at San Diego, La Jolla, CA, USA
- Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Chigoziri Konkwo
- Departments of Internal Medicine, Section of Digestive Diseases, and of Pathology, Yale School of Medicine, New Haven, CT, USA
| | - Saaket Agrawal
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Amit V. Khera
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Verve Therapeutics, Cambridge, MA, USA
| | - Rohit Loomba
- NAFLD Research Center, Division of Gastroenterology, University of California at San Diego, La Jolla, CA, USA
| | - Sílvia Vilarinho
- Departments of Internal Medicine, Section of Digestive Diseases, and of Pathology, Yale School of Medicine, New Haven, CT, USA
- Department of Pathology, Yale School of Medicine, New Haven, CT, USA
| | - Veeral Ajmera
- NAFLD Research Center, Division of Gastroenterology, University of California at San Diego, La Jolla, CA, USA
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Ajmera V. Towards omics-based risk assessment in NAFLD. Nat Metab 2023; 5:534-535. [PMID: 37037944 DOI: 10.1038/s42255-023-00772-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
Affiliation(s)
- Veeral Ajmera
- NAFLD Research Center, Division of Gastroenterology, University of California at San Diego, La Jolla, CA, USA.
- Division of Gastroenterology and Hepatology, University of California at San Diego, La Jolla, CA, USA.
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Amangurbanova M, Huang DQ, Loomba R. Review article: the role of HSD17B13 on global epidemiology, natural history, pathogenesis and treatment of NAFLD. Aliment Pharmacol Ther 2023; 57:37-51. [PMID: 36349732 PMCID: PMC10047549 DOI: 10.1111/apt.17292] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Revised: 10/07/2022] [Accepted: 10/23/2022] [Indexed: 11/11/2022]
Abstract
BACKGROUND Non-alcoholic fatty liver disease (NAFLD) occurs in around a quarter of the global population and is one of the leading causes of chronic liver disease. The phenotypic manifestation and the severity of NAFLD are influenced by an interplay of environmental and genetic factors. Recently, several inactivating variants in the novel 17-Beta hydroxysteroid dehydrogenase 13 (HSD17B13) gene have been found to be associated with a reduced risk of chronic liver diseases, including NAFLD. AIMS To review the existing literature on the epidemiology of HSD17B13 and discuss its role in the natural history, disease pathogenesis and treatment of NAFLD. METHODS We extensively searched relevant literature in PubMed, Google Scholar, clinicaltrials.gov and the reference list of articles included in the review. RESULTS HSD17B13 is a liver-specific, lipid droplet (LD)-associated protein that has enzymatic pathways involving steroids, pro-inflammatory lipid mediators and retinol. The estimated prevalence of the best characterised HSD17B13 variant (rs72613567) ranges from 5% in Africa to 34% in East Asia. Loss-of-function variants in HSD17B13 are protective against the progression of NAFLD from simple steatosis to non-alcoholic steatohepatitis (NASH), liver fibrosis, cirrhosis and hepatocellular carcinoma. Emerging data from mechanistic and preclinical studies with RNA interference (RNAi) and small molecule agents indicate that inhibiting HSD17B13 activity may prevent NAFLD progression. CONCLUSIONS The loss-of-function polymorphisms of the newly identified HSD17B13 gene mitigate the progression of NAFLD. It is important to understand the exact mechanism by which these variants exert a protective effect and implement the gathered knowledge in the treatment of NAFLD.
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Affiliation(s)
- Maral Amangurbanova
- NAFLD Research Center, Division of Gastroenterology. University of California at San Diego, La Jolla, CA, United States
| | - Daniel Q. Huang
- NAFLD Research Center, Division of Gastroenterology. University of California at San Diego, La Jolla, CA, United States
- Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
- Division of Gastroenterology and Hepatology, Department of Medicine, National University Health System, Singapore
| | - Rohit Loomba
- NAFLD Research Center, Division of Gastroenterology. University of California at San Diego, La Jolla, CA, United States
- Division of Epidemiology, Department of Family Medicine and Public Health, University of California at San Diego, San Diego, CA, United States
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14
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Tamaki N, Ahlholm N, Luukkonen PK, Porthan K, Sharpton SR, Ajmera V, Kono Y, Dave S, Ahmed A, Sundaram V, Wilkinson MJ, Patton H, Gupta H, Cervantes V, Hernandez C, Lopez SJ, Loomba R, Baumgartner A, Richards L, Arkkila PE, Nemes K, Isoniemi H, Yki-Järvinen H, Loomba R. Risk of advanced fibrosis in first-degree relatives of patients with nonalcoholic fatty liver disease. J Clin Invest 2022; 132:e162513. [PMID: 36317632 PMCID: PMC9621132 DOI: 10.1172/jci162513] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Accepted: 09/08/2022] [Indexed: 01/05/2023] Open
Abstract
BACKGROUNDA pilot, single-center study showed that first-degree relatives of probands with nonalcoholic fatty liver disease (NAFLD) cirrhosis have a high risk of advanced fibrosis. We aimed to validate these findings using 2 independent cohorts from the US and Europe.METHODSThis prospective study included probands with NAFLD with advanced fibrosis, NAFLD without advanced fibrosis, and non-NAFLD, with at least 1 first-degree relative. A total of 396 first-degree relatives - 220 in a derivation cohort and 176 in a validation cohort - were enrolled in the study, and liver fibrosis was evaluated using magnetic resonance elastography and other noninvasive imaging modalities. The primary outcome was prevalence of advanced fibrosis in first-degree relatives.RESULTSPrevalence of advanced fibrosis in first-degree relatives of probands with NAFLD with advanced fibrosis, NAFLD without advanced fibrosis, and non-NAFLD was 15.6%, 5.9%, and 1.3%, respectively (P = 0.002), in the derivation cohort, and 14.0%, 2.6%, and 1.3%, respectively (P = 0.004), in the validation cohort. In multivariable-adjusted logistic regression models, age of ≥50 years (adjusted OR [aOR]: 2.63, 95% CI 1.0-6.7), male sex (aOR: 3.79, 95% CI 1.6-9.2), diabetes mellitus (aOR: 3.37, 95% CI 1.3-9), and a first-degree relative with NAFLD with advanced fibrosis (aOR: 11.8, 95% CI 2.5-57) were significant predictors of presence of advanced fibrosis (all P < 0.05).CONCLUSIONFirst-degree relatives of probands with NAFLD with advanced fibrosis have significantly increased risk of advanced fibrosis. Routine screening should be done in the first-degree relatives of patients with advanced fibrosis.FUNDINGSupported by NCATS (5UL1TR001442), NIDDK (U01DK061734, U01DK130190, R01DK106419, R01DK121378, R01DK124318, P30DK120515, K23DK119460), NHLBI (P01HL147835), and NIAAA (U01AA029019); Academy of Finland grant 309263; the Novo Nordisk, EVO, and Sigrid Jusélius Foundations; and the Innovative Medicines Initiative 2 Joint Undertaking under grant agreement 777377. This Joint Undertaking receives support from the European Union's Horizon 2020 research and innovation program and the EFPIA.
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Affiliation(s)
- Nobuharu Tamaki
- Nonalcoholic Fatty Liver Disease Research Center, Division of Gastroenterology and Hepatology, Department of Medicine, University of California San Diego, La Jolla, California, USA
- Department of Gastroenterology and Hepatology, Musashino Red Cross Hospital, Tokyo, Japan
| | - Noora Ahlholm
- Department of Medicine, University of Helsinki, Helsinki University Hospital, Helsinki, Finland
- Minerva Foundation Institute for Medical Research, Helsinki, Finland
| | - Panu K. Luukkonen
- Department of Medicine, University of Helsinki, Helsinki University Hospital, Helsinki, Finland
- Minerva Foundation Institute for Medical Research, Helsinki, Finland
- Department of Internal Medicine, Yale University, New Haven, Connecticut, USA
| | - Kimmo Porthan
- Department of Medicine, University of Helsinki, Helsinki University Hospital, Helsinki, Finland
- Minerva Foundation Institute for Medical Research, Helsinki, Finland
| | - Suzanne R. Sharpton
- Nonalcoholic Fatty Liver Disease Research Center, Division of Gastroenterology and Hepatology, Department of Medicine, University of California San Diego, La Jolla, California, USA
| | - Veeral Ajmera
- Nonalcoholic Fatty Liver Disease Research Center, Division of Gastroenterology and Hepatology, Department of Medicine, University of California San Diego, La Jolla, California, USA
| | - Yuko Kono
- Division of Gastroenterology and Hepatology, Department of Medicine, University of California San Diego, La Jolla, California, USA
| | - Shravan Dave
- Division of Gastroenterology and Hepatology, Department of Medicine, University of California San Diego, La Jolla, California, USA
| | - Aijaz Ahmed
- Division of Gastroenterology and Hepatology, Stanford University School of Medicine, Stanford, California, USA
| | - Vinay Sundaram
- Karsh Division of Gastroenterology and Comprehensive Transplant Center, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Michael J. Wilkinson
- Division of Cardiovascular Diseases, Department of Medicine, University of California San Diego, La Jolla, California, USA
| | - Heather Patton
- Gastroenterology Section, VA San Diego Healthcare System, San Diego, California, USA
| | - Hersh Gupta
- Nonalcoholic Fatty Liver Disease Research Center, Division of Gastroenterology and Hepatology, Department of Medicine, University of California San Diego, La Jolla, California, USA
| | - Vanessa Cervantes
- Nonalcoholic Fatty Liver Disease Research Center, Division of Gastroenterology and Hepatology, Department of Medicine, University of California San Diego, La Jolla, California, USA
| | - Christie Hernandez
- Nonalcoholic Fatty Liver Disease Research Center, Division of Gastroenterology and Hepatology, Department of Medicine, University of California San Diego, La Jolla, California, USA
| | - Scarlett J. Lopez
- Nonalcoholic Fatty Liver Disease Research Center, Division of Gastroenterology and Hepatology, Department of Medicine, University of California San Diego, La Jolla, California, USA
| | - Ria Loomba
- Nonalcoholic Fatty Liver Disease Research Center, Division of Gastroenterology and Hepatology, Department of Medicine, University of California San Diego, La Jolla, California, USA
| | - Amanda Baumgartner
- Nonalcoholic Fatty Liver Disease Research Center, Division of Gastroenterology and Hepatology, Department of Medicine, University of California San Diego, La Jolla, California, USA
| | - Lisa Richards
- Nonalcoholic Fatty Liver Disease Research Center, Division of Gastroenterology and Hepatology, Department of Medicine, University of California San Diego, La Jolla, California, USA
| | | | - Katriina Nemes
- Department of Medicine, University of Helsinki, Helsinki University Hospital, Helsinki, Finland
- Transplantation and Liver Surgery Unit, Abdominal Center, University of Helsinki, Helsinki University Hospital, Helsinki, Finland
| | - Helena Isoniemi
- Transplantation and Liver Surgery Unit, Abdominal Center, University of Helsinki, Helsinki University Hospital, Helsinki, Finland
| | - Hannele Yki-Järvinen
- Department of Medicine, University of Helsinki, Helsinki University Hospital, Helsinki, Finland
- Minerva Foundation Institute for Medical Research, Helsinki, Finland
| | - Rohit Loomba
- Nonalcoholic Fatty Liver Disease Research Center, Division of Gastroenterology and Hepatology, Department of Medicine, University of California San Diego, La Jolla, California, USA
- Division of Gastroenterology and Hepatology, Department of Medicine, University of California San Diego, La Jolla, California, USA
- Division of Epidemiology, Department of Family Medicine and Public Health, University of California San Diego, La Jolla, California, USA
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15
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Kechagias S, Ekstedt M, Simonsson C, Nasr P. Non-invasive diagnosis and staging of non-alcoholic fatty liver disease. Hormones (Athens) 2022; 21:349-368. [PMID: 35661987 PMCID: PMC9464753 DOI: 10.1007/s42000-022-00377-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Accepted: 05/19/2022] [Indexed: 02/08/2023]
Abstract
Non-alcoholic fatty liver disease (NAFLD) is considered to be the hepatic manifestation of the metabolic syndrome and is characterized by ectopic accumulation of triglycerides in the cytoplasm of hepatocytes, i.e., steatosis. NAFLD has become the most common chronic liver disease, with an estimated global prevalence of 25%. Although the majority of NAFLD patients will never experience liver-related complications, the progressive potential of NAFLD is indisputable, with 5-10% of subjects progressing to cirrhosis, end-stage liver disease, or hepatocellular carcinoma. NAFLD patients with advanced fibrosis are at the highest risk of developing cardiovascular and cirrhosis-related complications. Liver biopsy has hitherto been considered the reference method for evaluation of hepatic steatosis and fibrosis stage. Given the limitations of biopsy for widescale screening, non-invasive tests (NITs) for assessment of steatosis and fibrosis stage, including serum-based algorithms and ultrasound- and magnetic resonance-based methods, will play an increasing role in the management of NAFLD patients. This comprehensive review presents the advantages and limitations of NITs for identification of steatosis and advanced fibrosis in NAFLD. The clinical implications of using NITs to identify and manage NAFLD patients are also discussed.
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Affiliation(s)
- Stergios Kechagias
- Department of Gastroenterology and Hepatology, University Hospital, Linköping, Sweden.
- Department of Health, Medical and Caring Sciences, Linköping University, Linköping, Sweden.
| | - Mattias Ekstedt
- Department of Gastroenterology and Hepatology, University Hospital, Linköping, Sweden
- Department of Health, Medical and Caring Sciences, Linköping University, Linköping, Sweden
| | - Christian Simonsson
- Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköping, Sweden
- Department of Biomedical Engineering, Linköping University, Linköping, Sweden
| | - Patrik Nasr
- Department of Gastroenterology and Hepatology, University Hospital, Linköping, Sweden
- Department of Health, Medical and Caring Sciences, Linköping University, Linköping, Sweden
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16
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Wajsbrot NB, Leite NC, Salles GF, Villela-Nogueira CA. Non-alcoholic fatty liver disease and the impact of genetic, epigenetic and environmental factors in the offspring. World J Gastroenterol 2022; 28:2890-2899. [PMID: 35978876 PMCID: PMC9280730 DOI: 10.3748/wjg.v28.i25.2890] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Revised: 03/20/2022] [Accepted: 05/14/2022] [Indexed: 02/06/2023] Open
Abstract
Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disease worldwide and is strongly associated with metabolic deregulation. More recently, a significant impact of parental NAFLD in the offspring was demonstrated and has been widely discussed. However, pathogenetic pathways implicated in the inheritance by the offspring and relatives are still under debate. Probably, multiple mechanisms are involved as well as in NAFLD pathogenesis itself. Among the multifactorial involved mechanisms, genetic, epigenetic and environmental backgrounds are strongly related to NAFLD development in the offspring. Thus, based on recent evidence from the available literature concerning genetic, epigenetic and environmental disease modifiers, this review aimed to discuss the relationship between parental NAFLD and its impact on the offspring.
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Affiliation(s)
- Natalia Balassiano Wajsbrot
- Division of Hepatology, Clementino Fraga Filho University Hospital, Federal University of Rio de Janeiro, Rio de Janeiro 20941-913, Brazil
| | - Nathalie Carvalho Leite
- Division of Hepatology, Clementino Fraga Filho University Hospital, Federal University of Rio de Janeiro, Rio de Janeiro 20941-913, Brazil
| | - Gil F Salles
- Department of Internal Medicine, Medical School, Federal University of Rio de Janeiro, Rio de Janeiro 22750-240, Brazil
| | - Cristiane A Villela-Nogueira
- Department of Internal Medicine, Medical School, Federal University of Rio de Janeiro, Rio de Janeiro 22750-240, Brazil
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Varadharajan V, Massey WJ, Brown JM. Membrane-bound O-acyltransferase 7 (MBOAT7)-driven phosphatidylinositol remodeling in advanced liver disease. J Lipid Res 2022; 63:100234. [PMID: 35636492 PMCID: PMC9240865 DOI: 10.1016/j.jlr.2022.100234] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 05/12/2022] [Accepted: 05/16/2022] [Indexed: 01/21/2023] Open
Abstract
Advanced liver diseases account for approximately 2 million deaths annually worldwide. Roughly, half of liver disease-associated deaths arise from complications of cirrhosis and the other half driven by viral hepatitis and hepatocellular carcinoma. Unfortunately, the development of therapeutic strategies to treat subjects with advanced liver disease has been hampered by a lack of mechanistic understanding of liver disease progression and a lack of human-relevant animal models. An important advance has been made within the past several years, as several genome-wide association studies have discovered that an SNP near the gene encoding membrane-bound O-acyltransferase 7 (MBOAT7) is associated with severe liver diseases. This common MBOAT7 variant (rs641738, C>T), which reduces MBOAT7 expression, confers increased susceptibility to nonalcoholic fatty liver disease, alcohol-associated liver disease, and liver fibrosis in patients chronically infected with viral hepatitis. Recent studies in mice also show that Mboat7 loss of function can promote hepatic steatosis, inflammation, and fibrosis, causally linking this phosphatidylinositol remodeling enzyme to liver health in both rodents and humans. Herein, we review recent insights into the mechanisms by which MBOAT7-driven phosphatidylinositol remodeling influences liver disease progression and discuss how rapid progress in this area could inform drug discovery moving forward.
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Affiliation(s)
- Venkateshwari Varadharajan
- Department of Cardiovascular and Metabolic Sciences, Lerner Research Institute Cleveland Clinic, Cleveland, OH, USA; Center for Microbiome and Human Health, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
| | - William J Massey
- Department of Cardiovascular and Metabolic Sciences, Lerner Research Institute Cleveland Clinic, Cleveland, OH, USA; Center for Microbiome and Human Health, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
| | - J Mark Brown
- Department of Cardiovascular and Metabolic Sciences, Lerner Research Institute Cleveland Clinic, Cleveland, OH, USA; Center for Microbiome and Human Health, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA.
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18
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Natarajan Y, Loomba R. Magnetic Resonance Elastography for the Clinical Risk Assessment of Fibrosis, Cirrhosis, and Portal Hypertension in Patients With NAFLD. J Clin Exp Hepatol 2022; 12:174-179. [PMID: 35068797 PMCID: PMC8766685 DOI: 10.1016/j.jceh.2021.08.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Accepted: 08/01/2021] [Indexed: 01/03/2023] Open
Abstract
Nonalcoholic fatty liver disease (NAFLD) is rapidly becoming one of the most common causes of liver disease. The progressive subtype of NAFLD, nonalcoholic steatohepatitis (NASH), leads to cirrhosis, hepatocellular carcinoma, and mortality. Fibrosis is the strongest predictor for complications. Due to the invasive nature of liver biopsy, noninvasive testing methods have emerged to detect fibrosis and predict outcomes. Of these modalities, magnetic resonance elastography (MRE) has demonstrated the highest accuracy to detect fibrosis. In this review, we will focus on the emerging data regarding MRE and liver fibrosis, cirrhosis, and portal hypertension in NAFLD.
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Affiliation(s)
- Yamini Natarajan
- Section of Gastroenterology and Hepatology, Department of Medicine, Baylor College of Medicine, USA,Clinical Epidemiology and Comparative Effectiveness Program, Section of Health Services Research (IQuESt), Michael E. DeBakey VA Medical Center and Baylor College of Medicine, Houston, TX, USA,Address for correspondence. Yamini Natarajan, MD, 2002 Holcombe Blvd (111-D), Houston, TX, 77030, USA.
| | - Rohit Loomba
- NAFLD Research Center, Division of Gastroenterology, Department of Medicine, University of California at San Diego, La Jolla, CA, USA,Address for correspondence. Rohit Loomba, MD, MHSc, 9500 Gilman Drive, ACTRI Building, 2W202, La Jolla, CA, 92093-0887, USA. http://fattyliver.ucsd.edu
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19
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Tamaki N, Ajmera V, Loomba R. Non-invasive methods for imaging hepatic steatosis and their clinical importance in NAFLD. Nat Rev Endocrinol 2022; 18:55-66. [PMID: 34815553 PMCID: PMC9012520 DOI: 10.1038/s41574-021-00584-0] [Citation(s) in RCA: 84] [Impact Index Per Article: 42.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 10/11/2021] [Indexed: 01/27/2023]
Abstract
Hepatic steatosis is a key histological feature of nonalcoholic fatty liver disease (NAFLD). The non-invasive quantification of liver fat is now possible due to advances in imaging modalities. Emerging data suggest that high levels of liver fat and its temporal change, as measured by quantitative non-invasive methods, might be associated with NAFLD progression. Ultrasound-based modalities have moderate diagnostic accuracy for liver fat content and are suitable for screening. However, of the non-invasive imaging modalities, MRI-derived proton density fat fraction (MRI-PDFF) has the highest diagnostic accuracy and is used for trial enrolment and to evaluate therapeutic effects in early-phase clinical trials in nonalcoholic steatohepatitis (NASH). In patients with NAFLD without advanced fibrosis, high levels of liver fat are associated with rapid disease progression. Furthermore, changes on MRI-PDFF (≥30% decline relative to baseline) are associated with NAFLD activity score improvement and fibrosis regression. However, an inverse association exists between liver fat and complications of cirrhosis. Liver fat decreases as liver fibrosis progresses towards cirrhosis, and the clinical importance of quantitative measurements of liver fat differs by NAFLD status. As such, patients with NAFLD should be stratified by fibrosis severity to investigate the utility of quantitative measurements of liver fat for assessing NAFLD progression and prognosis.
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Affiliation(s)
- Nobuharu Tamaki
- NAFLD Research Center, Division of Gastroenterology and Hepatology, Department of Medicine, University of California San Diego, La Jolla, CA, USA
- Department of Gastroenterology and Hepatology, Musashino Red Cross Hospital, Tokyo, Japan
| | - Veeral Ajmera
- NAFLD Research Center, Division of Gastroenterology and Hepatology, Department of Medicine, University of California San Diego, La Jolla, CA, USA
| | - Rohit Loomba
- NAFLD Research Center, Division of Gastroenterology and Hepatology, Department of Medicine, University of California San Diego, La Jolla, CA, USA.
- The Herbert Wertheim School of Public Health and Human Longevity Science, University of California San Diego, La Jolla, CA, USA.
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20
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Vilarinho S, Ajmera V, Zheng M, Loomba R. Emerging Role of Genomic Analysis in Clinical Evaluation of Lean Individuals With NAFLD. Hepatology 2021; 74:2241-2250. [PMID: 34233030 PMCID: PMC8463418 DOI: 10.1002/hep.32047] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 05/25/2021] [Accepted: 07/01/2021] [Indexed: 12/18/2022]
Abstract
Whereas the rising prevalence of nonalcoholic fatty liver disease (NAFLD) is closely related with the global obesity epidemic, up to 10–20% of individuals with NAFLD are lean as defined by a body mass index of < 25 kg/m2, or < 23 kg/m2 in Asians. This entity designated as “lean NAFLD” is estimated to affect 8 to 10 million individuals in the United States alone. Here, we review the emerging data on the epidemiology, natural history and prognosis of lean NAFLD and put forward a diagnostic approach that combines detailed clinical phenotyping with genomic analysis. We propose two subtypes of lean NAFLD referred to as type 1: individuals with visceral adiposity and insulin resistance but normal BMI; and type 2: lean individuals with hepatic steatosis secondary to a known or unknown monogenic disease. We envision that incorporation of genomic analysis in the diagnostic algorithm of lean patients with NAFLD will elucidate the contribution of common genetic variants through the calculation of NAFLD polygenic risk score and also characterize the diverse array of rare monogenic diseases that can lead to triglyceride accumulation in the cytoplasm of hepatocytes. Collectively, the integration of a molecular diagnosis in the clinical evaluation of patients with lean NAFLD will provide an accurate diagnosis, with possible targeted therapies and may uncover novel molecular mechanisms with potential broader therapeutic implications.
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Affiliation(s)
- Sílvia Vilarinho
- Departments of Internal Medicine, Section of Digestive Diseases, and of Pathology, Yale School of Medicine, New Haven, CT
| | - Veeral Ajmera
- NAFLD Research Center, Division of Gastroenterology. University of California at San Diego, La Jolla, CA, USA
| | - Melanie Zheng
- Departments of Internal Medicine, Section of Digestive Diseases, and of Pathology, Yale School of Medicine, New Haven, CT
| | - Rohit Loomba
- NAFLD Research Center, Division of Gastroenterology. University of California at San Diego, La Jolla, CA, USA
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