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Della Torre S. Non-alcoholic Fatty Liver Disease as a Canonical Example of Metabolic Inflammatory-Based Liver Disease Showing a Sex-Specific Prevalence: Relevance of Estrogen Signaling. Front Endocrinol (Lausanne) 2020; 11:572490. [PMID: 33071979 PMCID: PMC7531579 DOI: 10.3389/fendo.2020.572490] [Citation(s) in RCA: 52] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2020] [Accepted: 08/20/2020] [Indexed: 12/11/2022] Open
Abstract
There is extensive evidence supporting the interplay between metabolism and immune response, that have evolved in close relationship, sharing regulatory molecules and signaling systems, to support biological functions. Nowadays, the disruption of this interaction in the context of obesity and overnutrition underlies the increasing incidence of many inflammatory-based metabolic diseases, even in a sex-specific fashion. During evolution, the interplay between metabolism and reproduction has reached a degree of complexity particularly high in female mammals, likely to ensure reproduction only under favorable conditions. Several factors may account for differences in the incidence and progression of inflammatory-based metabolic diseases between females and males, thus contributing to age-related disease development and difference in life expectancy between the two sexes. Among these factors, estrogens, acting mainly through Estrogen Receptors (ERs), have been reported to regulate several metabolic pathways and inflammatory processes particularly in the liver, the metabolic organ showing the highest degree of sexual dimorphism. This review aims to investigate on the interaction between metabolism and inflammation in the liver, focusing on the relevance of estrogen signaling in counteracting the development and progression of non-alcoholic fatty liver disease (NAFLD), a canonical example of metabolic inflammatory-based liver disease showing a sex-specific prevalence. Understanding the role of estrogens/ERs in the regulation of hepatic metabolism and inflammation may provide the basis for the development of sex-specific therapeutic strategies for the management of such an inflammatory-based metabolic disease and its cardio-metabolic consequences.
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Affiliation(s)
- Sara Della Torre
- Department of Pharmaceutical Sciences, University of Milan, Milan, Italy
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Rescue of Hepatic Phospholipid Remodeling Defectin iPLA2β-Null Mice Attenuates Obese but Not Non-Obese Fatty Liver. Biomolecules 2020; 10:biom10091332. [PMID: 32957701 PMCID: PMC7565968 DOI: 10.3390/biom10091332] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Revised: 09/15/2020] [Accepted: 09/15/2020] [Indexed: 12/19/2022] Open
Abstract
Polymorphisms of group VIA calcium-independent phospholipase A2 (iPLA2β or PLA2G6) are positively associated with adiposity, blood lipids, and Type-2 diabetes. The ubiquitously expressed iPLA2β catalyzes the hydrolysis of phospholipids (PLs) to generate a fatty acid and a lysoPL. We studied the role of iPLA2β on PL metabolism in non-alcoholic fatty liver disease (NAFLD). By using global deletion iPLA2β-null mice, we investigated three NAFLD mouse models; genetic Ob/Ob and long-term high-fat-diet (HFD) feeding (representing obese NAFLD) as well as feeding with methionine- and choline-deficient (MCD) diet (representing non-obese NAFLD). A decrease of hepatic PLs containing monounsaturated- and polyunsaturated fatty acids and a decrease of the ratio between PLs and cholesterol esters were observed in all three NAFLD models. iPLA2β deficiency rescued these decreases in obese, but not in non-obese, NAFLD models. iPLA2β deficiency elicited protection against fatty liver and obesity in the order of Ob/Ob › HFD » MCD. Liver inflammation was not protected in HFD NAFLD, and that liver fibrosis was even exaggerated in non-obese MCD model. Thus, the rescue of hepatic PL remodeling defect observed in iPLA2β-null mice was critical for the protection against NAFLD and obesity. However, iPLA2β deletion in specific cell types such as macrophages may render liver inflammation and fibrosis, independent of steatosis protection.
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Barchetta I, Cimini FA, Chiappetta C, Bertoccini L, Ceccarelli V, Capoccia D, Gaggini M, Di Cristofano C, Della Rocca C, Silecchia G, Leonetti F, Lenzi A, Gastaldelli A, Cavallo MG. Relationship between hepatic and systemic angiopoietin-like 3, hepatic Vitamin D receptor expression and NAFLD in obesity. Liver Int 2020; 40:2139-2147. [PMID: 32510837 DOI: 10.1111/liv.14554] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 05/26/2020] [Accepted: 05/29/2020] [Indexed: 02/06/2023]
Abstract
BACKGROUND & AIMS Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disease worldwide and an independent risk factor for cardiovascular mortality. Angiopoietin-like proteins (ANGPTLs) are targets for vitamin D receptor (VDR)-mediated gene transcription and this axis may promote NAFLD. ANGPTL3 is a hepatokine which inhibits lipoprotein lipase and its experimentally induced inactivation reduces hepatosteatosis. Little is known on ANGPTL3 in human NAFLD and no data exist on its relationship with hepatic VDR/VD-related genes. The aim of this research was to investigate hepatic ANGPTLs and VDR/VD-related gene expression in human obesity in relation to NAFLD. METHODS We conducted a cross-sectional investigation on forty obese subjects with/without NAFLD. We evaluated hepatic ANGPTL3, ANGPTL4, ANGPTL8, LPL, VDR, CYP27A1 and CYP2R1 mRNA expression in liver biopsies by RT-PCR; VDR expression was further investigated by immunohistochemistry; circulating ANGPTL3 was measured by Milliplex assay. RESULTS Compared to non-NAFLD, NAFLD individuals had significantly higher hepatic VDR, ANGPTL3 and LPL expression. ANGPTL3 correlated with steatosis grade, LPL, VDR, CYP27A1 and CYP2R1 expression. Plasma ANGPTL3 concentrations were positively associated with clinical/histological markers of NAFLD/NASH and with hepatic ANGPTL3 expression. Greater hepatic VDR expression was the main determinant of hepatic ANGPTL3 after adjusting for multiple confounders. CONCLUSIONS Hepatic ANGPTL3 expression correlates with greater VDR expression, presence and severity of NAFLD and translates in increased circulating ANGPTL3, likely as a result of its modulation by up-regulated hepatic VDR in NAFLD. This study provides novel insights to potential mechanisms underlying ANGPTLs-mediated ectopic fat accumulation and NAFLD development in obesity.
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Affiliation(s)
- Ilaria Barchetta
- Department of Experimental Medicine, Sapienza University of Rome, Rome, Italy
| | - Flavia A Cimini
- Department of Experimental Medicine, Sapienza University of Rome, Rome, Italy
| | - Caterina Chiappetta
- Department of Medical-Surgical Sciences and Biotechnologies, Sapienza University of Rome, Rome, Italy
| | - Laura Bertoccini
- Department of Experimental Medicine, Sapienza University of Rome, Rome, Italy
| | | | - Danila Capoccia
- Department of Medical-Surgical Sciences and Biotechnologies, Sapienza University of Rome, Rome, Italy
| | - Melania Gaggini
- Cardiometabolic Risk Unit, Institute of Clinical Physiology, CNR, Pisa, Italy
| | - Claudio Di Cristofano
- Department of Medical-Surgical Sciences and Biotechnologies, Sapienza University of Rome, Rome, Italy
| | - Carlo Della Rocca
- Department of Medical-Surgical Sciences and Biotechnologies, Sapienza University of Rome, Rome, Italy
| | - Gianfranco Silecchia
- Department of Medical-Surgical Sciences and Biotechnologies, Sapienza University of Rome, Rome, Italy
| | - Frida Leonetti
- Department of Medical-Surgical Sciences and Biotechnologies, Sapienza University of Rome, Rome, Italy
| | - Andrea Lenzi
- Department of Experimental Medicine, Sapienza University of Rome, Rome, Italy
| | - Amalia Gastaldelli
- Cardiometabolic Risk Unit, Institute of Clinical Physiology, CNR, Pisa, Italy
| | - Maria G Cavallo
- Department of Experimental Medicine, Sapienza University of Rome, Rome, Italy
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Yang M, Liu Q, Huang T, Tan W, Qu L, Chen T, Pan H, Chen L, Liu J, Wong CW, Lu WW, Guan M. Dysfunction of estrogen-related receptor alpha-dependent hepatic VLDL secretion contributes to sex disparity in NAFLD/NASH development. Theranostics 2020; 10:10874-10891. [PMID: 33042259 PMCID: PMC7532682 DOI: 10.7150/thno.47037] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Accepted: 08/04/2020] [Indexed: 12/12/2022] Open
Abstract
Rationale: Men and postmenopausal women are more prone to developing non-alcoholic fatty liver disease/steatohepatitis (NAFLD/NASH) than premenopausal women. However, the pathological links and underlying mechanisms of this disparity are still elusive. The sex-difference in hepatic very low-density lipoprotein (VLDL) assembly and secretion may contribute to NAFLD development. Estrogen-related receptor alpha (ERRα) is a key regulator of several metabolic processes. We hypothesized that ERRα plays a role contributing to the sex-difference in hepatic VLDL assembly and secretion. Methods: VLDL secretion and essential genes governing said process were assessed in male and female mice. Liver-specific ERRα-deficient (ERRαLKO) mice were generated to assess the rate of hepatic VLDL secretion and alteration in target gene expression. Overexpression of either microsomal triglyceride transfer protein (Mttp) or phospholipase A2 G12B (Pla2g12b) by adenovirus was performed to test if the fatty liver phenotype in male ERRαLKO mice was due to defects in hepatic VLDL secretion. Female ERRαLKO mice were put on a diet high in saturated fat, fructose and cholesterol (HFHC) to promote NASH development. Wild type female mice were either ovariectomized or treated with tamoxifen to induce a state of estrogen deficiency or disruption in estrogen signaling. Adenovirus was used to overexpress ERRα in these mice to test if ERRα was sufficient to rescue the suppressed VLDL secretion due to estrogen dysfunction. Finally, wild type male mice on a high-fat diet (HFD) were treated with an ERRα inverse agonist to assess if suppressing ERRα activity pharmacologically would lead to fatty liver development. Results: ERRα is an indispensable mediator modulating hepatic triglyceride-rich very low-density lipoprotein (VLDL-TG) assembly and secretion through coordinately controlling target genes apolipoprotein B (Apob), Mttp and Pla2g12b in a sex-different manner. Hepatic VLDL-TG secretion is blunted in ERRαLKO mice, leading to hepatosteatosis which exacerbates endoplasmic reticulum stress and inflammation paving ways for NASH development. Importantly, ERRα acts downstream of estrogen/ERα signaling in contributing to the sex-difference in hepatic VLDL secretion effecting hepatic lipid homeostasis. Conclusions: Our results highlight ERRα as a key mediator which contributes to the sex disparity in NAFLD development, suggesting that selectively restoring ERRα activity in the liver may be a novel strategy for treating NAFLD/NASH.
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Affiliation(s)
- Meng Yang
- Center for Human Tissues and Organs Degeneration, Institute of Biomedicine and Biotechnology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, Guangdong, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Qingli Liu
- Center for Human Tissues and Organs Degeneration, Institute of Biomedicine and Biotechnology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, Guangdong, China
| | - Tongling Huang
- Center for Human Tissues and Organs Degeneration, Institute of Biomedicine and Biotechnology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, Guangdong, China
| | - Wenjuan Tan
- School of Life Sciences, Faculty of Science, The Chinese University of Hong Kong, Hong Kong, China
| | - Linbing Qu
- Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou 510530, Guangdong, China
| | - Tianke Chen
- Center for Human Tissues and Organs Degeneration, Institute of Biomedicine and Biotechnology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, Guangdong, China
| | - Haobo Pan
- Center for Human Tissues and Organs Degeneration, Institute of Biomedicine and Biotechnology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, Guangdong, China
| | - Ling Chen
- Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou 510530, Guangdong, China
| | - Jinsong Liu
- Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou 510530, Guangdong, China
| | - Chi-Wai Wong
- NeuMed Pharmaceuticals Limited, Yuen Long, Hong Kong, China
| | - William W. Lu
- Department of Orthopaedics and Traumatology, The University of Hong Kong, Hong Kong, China
| | - Min Guan
- Center for Human Tissues and Organs Degeneration, Institute of Biomedicine and Biotechnology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, Guangdong, China
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Gender-specific differences in clinical and metabolic variables associated with NAFLD in a Mexican pediatric population. Ann Hepatol 2020; 18:693-700. [PMID: 31151875 DOI: 10.1016/j.aohep.2019.04.012] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Revised: 04/05/2019] [Accepted: 02/08/2019] [Indexed: 02/04/2023]
Abstract
INTRODUCTION AND OBJECTIVES Non-alcoholic fatty liver disease (NAFLD) is the most common liver disease in children and it is more prevalent in Hispanic males. The gender differences can be explained by body fat distribution, lifestyle, or sex hormone metabolism. We evaluated anthropometric and metabolic differences by gender in children with and without NAFLD. METHODS We included 194 participants (eutrophic, overweight, and individuals with obesity). The presence of NAFLD was determined using ultrasonography, and we evaluated the association between this disease with metabolic and anthropometric variables by gender. RESULTS The mean age was 10.64±2.54 years. The frequency of NAFLD in boys was 24.51% and in girls was 11.96% (OR=2.39; 95%CI=1.10-5.19; p=0.025). For girls, NAFLD was significantly associated with triglycerides (p=0.012), homeostatic model assessment of insulin resistance (HOMA-IR) (p=0.048), and the visceral adiposity index (VAI) (p=0.024). The variables related to NAFLD in a gender-specific manner were body mass index (BMI) (p=0.001), waist circumference (WC) (p<0.001), HDL cholesterol (p=0.021), alanine aminotransferase (ALT) (p<0.001), and aspartate aminotransferase (AST) (p=0.002). CONCLUSIONS In our study NAFLD is more frequent in boys, only ALT, and no other clinical or metabolic variables, were associated with NAFLD in these patients. HOMA-IR, VAI, triglyceride levels, and ALT were associated with NAFLD only in girls. The ALT cut-off points for the development of NAFLD in our study were 28.5U/L in females and 27.5U/L in males. Our findings showed that NAFLD should be intentionally screened in patients with obesity, particularly in boys.
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Hodson L, Parry SA, Cornfield T, Charlton C, Low WS, Green CJ, Rosqvist F. Using total plasma triacylglycerol to assess hepatic de novo lipogenesis as an alternative to VLDL triacylglycerol. Ups J Med Sci 2020; 125:211-216. [PMID: 32208800 PMCID: PMC7446043 DOI: 10.1080/03009734.2020.1739789] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Revised: 03/02/2020] [Accepted: 03/04/2020] [Indexed: 12/22/2022] Open
Abstract
Background: Hepatic de novo lipogenesis (DNL) is ideally measured in very low-density lipoprotein (VLDL)-triacylglycerol (TAG). In the fasting state, the majority of plasma TAG typically represents VLDL-TAG; however, the merits of measuring DNL in total plasma TAG have not been assessed. This study aimed to assess the performance of DNL measured in VLDL-TAG (DNLVLDL-TAG) compared to that measured in total plasma TAG (DNLPlasma-TAG).Methods: Using deuterated water, newly synthesised palmitate was determined in fasting plasma VLDL-TAG and total TAG in 63 subjects taking part in multiple studies resulting in n = 123 assessments of DNL (%new palmitate of total palmitate). Subjects were split into tertiles to investigate if DNLPlasma-TAG could correctly classify subjects having 'high' (top tertile) and 'low' (bottom tertile) DNL. Repeatability was assessed in a subgroup (n = 16) with repeat visits.Results: DNLVLDL-TAG was 6.8% (IQR 3.6-10.7%) and DNLPlasma-TAG was 7.5% (IQR 4.0%-11.0%), and the correlation between the methods was rs = 0.62 (p < 0.0001). Bland-Altman plots demonstrated similar performance (mean difference 0.81%, p = 0.09); however, the agreement interval was wide (-9.6% to 11.2%). Compared to DNLVLDL-TAG, 54% of subjects with low DNL were correctly classified, whilst 66% of subjects with high DNL were correctly classified using DNLPlasma-TAG. Repeatability was acceptable (i.e. not different) at the group level, but the majority of subjects had an intra-individual variability over 25%.Conclusion: DNL in total plasma TAG performed similarly to DNL in VLDL-TAG at the group level, but there was large variability at the individual level. We suggest that plasma TAG could be useful for comparing DNL between groups.
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Affiliation(s)
- Leanne Hodson
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Churchill Hospital, University of Oxford, Oxford, UK
- National Institute for Health Research Oxford Biomedical Research Centre, Oxford University Hospitals Foundation Trust, Oxford, UK
| | - Sion A. Parry
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Churchill Hospital, University of Oxford, Oxford, UK
| | - Thomas Cornfield
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Churchill Hospital, University of Oxford, Oxford, UK
| | - Catriona Charlton
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Churchill Hospital, University of Oxford, Oxford, UK
| | - Wee Suan Low
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Churchill Hospital, University of Oxford, Oxford, UK
| | - Charlotte J. Green
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Churchill Hospital, University of Oxford, Oxford, UK
| | - Fredrik Rosqvist
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Churchill Hospital, University of Oxford, Oxford, UK
- Department of Public Health and Caring Sciences, Clinical Nutrition and Metabolism, Uppsala University, Uppsala, Sweden
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Bisaccia G, Ricci F, Mantini C, Tana C, Romani GL, Schiavone C, Gallina S. Nonalcoholic fatty liver disease and cardiovascular disease phenotypes. SAGE Open Med 2020; 8:2050312120933804. [PMID: 32612827 PMCID: PMC7307287 DOI: 10.1177/2050312120933804] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Accepted: 05/21/2020] [Indexed: 12/12/2022] Open
Abstract
Nonalcoholic fatty liver disease is increasingly recognized as a major global health problem. Intertwined with diabetes, metabolic syndrome, and obesity, nonalcoholic fatty liver disease embraces a spectrum of liver conditions spanning from steatosis to inflammation, fibrosis, and liver failure. Compared with the general population, the prevalence of cardiovascular disease is higher among nonalcoholic fatty liver disease patients, in whom comprehensive cardiovascular risk assessment is highly desirable. Preclinical effects of nonalcoholic fatty liver disease on the heart include both metabolic and structural changes eventually preceding overt myocardial dysfunction. Particularly, nonalcoholic fatty liver disease is associated with enhanced atherosclerosis, heart muscle disease, valvular heart disease, and arrhythmias, with endothelial dysfunction, inflammation, metabolic dysregulation, and oxidative stress playing in the background. In this topical review, we aimed to summarize current evidence on the epidemiology of nonalcoholic fatty liver disease, discuss the pathophysiological links between nonalcoholic fatty liver disease and cardiovascular disease, illustrate nonalcoholic fatty liver disease-related cardiovascular phenotypes, and finally provide a glimpse on the relationship between nonalcoholic fatty liver disease and cardiac steatosis, mitochondrial (dys)function, and cardiovascular autonomic dysfunction.
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Affiliation(s)
- Giandomenico Bisaccia
- Department of Neuroscience, Imaging and Clinical Sciences, Institute for Advanced Biomedical Technologies, "G. d'Annunzio" University of Chieti and Pescara, Chieti, Italy
| | - Fabrizio Ricci
- Department of Neuroscience, Imaging and Clinical Sciences, Institute for Advanced Biomedical Technologies, "G. d'Annunzio" University of Chieti and Pescara, Chieti, Italy.,Department of Clinical Sciences, Lund University, Malmö, Sweden
| | - Cesare Mantini
- Department of Neuroscience, Imaging and Clinical Sciences, Institute for Advanced Biomedical Technologies, "G. d'Annunzio" University of Chieti and Pescara, Chieti, Italy
| | - Claudio Tana
- Internal Medicine and Critical Subacute Care Unit, Medicine Geriatric-Rehabilitation Department, and Department of Medicine and Surgery, University Hospital of Parma, Parma, Italy
| | - Gian Luca Romani
- Department of Neuroscience, Imaging and Clinical Sciences, Institute for Advanced Biomedical Technologies, "G. d'Annunzio" University of Chieti and Pescara, Chieti, Italy
| | - Cosima Schiavone
- Department of Internistic Ultrasound, "G. d'Annunzio" University of Chieti and Pescara, Chieti, Italy
| | - Sabina Gallina
- Department of Neuroscience, Imaging and Clinical Sciences, Institute for Advanced Biomedical Technologies, "G. d'Annunzio" University of Chieti and Pescara, Chieti, Italy
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Report of a member-led meeting: how stable isotope techniques can enhance human nutrition research. Proc Nutr Soc 2020; 79:373-379. [PMID: 32495731 DOI: 10.1017/s0029665120007016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
A Nutrition Society member-led meeting was held on 9 January 2020 at The University of Surrey, UK. Sixty people registered for the event, and all were invited to participate, either through chairing a session, presenting a '3 min lightning talk' or by presenting a poster. The meeting consisted of an introduction to the topic by Dr Barbara Fielding, with presentations from eight invited speakers. There were also eight lightning talks and a poster session. The meeting aimed to highlight recent research that has used stable isotope tracer techniques to understand human metabolism. Such studies have irrefutably shaped our current understanding of metabolism and yet remain a mystery to many. The meeting aimed to de-mystify their use in nutrition research.
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Lau-Corona D, Bae WK, Hennighausen L, Waxman DJ. Sex-biased genetic programs in liver metabolism and liver fibrosis are controlled by EZH1 and EZH2. PLoS Genet 2020; 16:e1008796. [PMID: 32428001 PMCID: PMC7263639 DOI: 10.1371/journal.pgen.1008796] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 06/01/2020] [Accepted: 04/24/2020] [Indexed: 12/15/2022] Open
Abstract
Sex differences in the incidence and progression of many liver diseases, including liver fibrosis and hepatocellular carcinoma, are associated with sex-biased hepatic expression of hundreds of genes. This sexual dimorphism is largely determined by the sex-specific pattern of pituitary growth hormone secretion, which controls a transcriptional regulatory network operative in the context of sex-biased and growth hormone-regulated chromatin states. Histone H3K27-trimethylation yields a major sex-biased repressive chromatin mark deposited at many strongly female-biased genes in male mouse liver, but not at male-biased genes in female liver, and is catalyzed by polycomb repressive complex-2 through its homologous catalytic subunits, Ezh1 and Ezh2. Here, we used Ezh1-knockout mice with a hepatocyte-specific knockout of Ezh2 to investigate the sex bias of liver H3K27-trimethylation and its functional role in regulating sex-differences in the liver. Combined hepatic Ezh1/Ezh2 deficiency led to a significant loss of sex-biased gene expression, particularly in male liver, where many female-biased genes were increased in expression while male-biased genes showed decreased expression. The associated loss of H3K27me3 marks, and increases in the active enhancer marks H3K27ac and H3K4me1, were also more pronounced in male liver. Further, Ezh1/Ezh2 deficiency in male liver, and to a lesser extent in female liver, led to up regulation of many genes linked to liver fibrosis and liver cancer, which may contribute to the observed liver pathologies and the increased sensitivity of these mice to hepatotoxin exposure. Thus, Ezh1/Ezh2-catalyzed H3K27-trimethyation regulates sex-dependent genetic programs in liver metabolism and liver fibrosis through its sex-dependent effects on the epigenome, and may thereby determine the sex-bias in liver disease susceptibility. Sex-differences in the expression of genes in liver have a direct impact on liver diseases whose incidence and severity is sex-biased, and is controlled by hormones that regulate chemical alterations to histone proteins used to package chromosomal DNA. However, a direct demonstration of the functional importance of such sex differences in histone protein modifications has been elusive. Here, we address this question using a mouse model deficient in two enzymes, Ezh1/Ezh2, which generate the histone repressive mark H3K27me3. Remarkably, although H3K27me3 marks are formed by Ezh1/Ezh2 throughout the genome, loss of liver Ezh1/Ezh2 preferentially disrupts the control of sex-biased genes, with expression increasing in male mouse liver for many female-biased genes and decreasing for many male-biased genes. Sex-biased H3K27me3 repressive marks were abolished, and there was a gain of active histone marks at gene enhancers. We also found increased expression of many genes associated with liver fibrosis and hepatocellular carcinoma, which may help explain the increased sensitivity of Ezh1/Ezh2-deficient livers to hepatotoxic chemicals whose exposure may lead to sex differences in liver disease incidence and susceptibility. Thus, our findings highlight the potential role of sex differences in histone modifications catalyzed by Ezh1/Ezh2 in widespread sex differences in liver diseases.
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Affiliation(s)
- Dana Lau-Corona
- Department of Biology and Bioinformatics Program, Boston University, Boston, Massachusetts, United States of America
| | - Woo Kyun Bae
- Laboratory of Genetics and Physiology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
- Department of Internal Medicine, Chonnam National University Medical School, Gwangju, Korea
| | - Lothar Hennighausen
- Laboratory of Genetics and Physiology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - David J. Waxman
- Department of Biology and Bioinformatics Program, Boston University, Boston, Massachusetts, United States of America
- * E-mail:
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Fappi A, Mittendorfer B. Different physiological mechanisms underlie an adverse cardiovascular disease risk profile in men and women. Proc Nutr Soc 2020; 79:210-218. [PMID: 31340878 PMCID: PMC7583670 DOI: 10.1017/s0029665119001022] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
CVD affect about one-third of the population and are the leading cause of mortality. The prevalence of CVD is closely linked to the prevalence of obesity because obesity is commonly associated with metabolic abnormalities that are important risk factors for CVD, including insulin resistance, pre-diabetes, and type-2 diabetes, atherosclerotic dyslipidaemia, endothelial dysfunction and hypertension. Women have a more beneficial traditional CVD risk profile (lower fasting plasma glucose, less atherogenic lipid profile) and a lower absolute risk for CVD than men. However, the relative risk for CVD associated with hyperglycaemia and dyslipidaemia is several-fold higher in women than in men. The reasons for the sex differences in CVD risk associated with metabolic abnormalities are unclear but could be related to differences in the mechanisms that cause hyperglycaemia and dyslipidaemia in men and women, which could influence the pathogenic processes involved in CVD. In the present paper, we review the influence of a person's sex on key aspects of metabolism involved in the cardiometabolic disease process, including insulin action on endogenous glucose production, tissue glucose disposal, and adipose tissue lipolysis, insulin secretion and insulin plasma clearance, postprandial glucose, fatty acid, and triglyceride kinetics, hepatic lipid metabolism and myocardial substrate use. We conclude that there are marked differences in many aspects of metabolism in men and women that are not all attributable to differences in the sex hormone milieu. The mechanisms responsible for these differences and the clinical implications of these observations are unclear and require further investigation.
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Affiliation(s)
- Alan Fappi
- Center for Human Nutrition, Washington University School of Medicine, St. Louis, MO, USA
| | - Bettina Mittendorfer
- Center for Human Nutrition, Washington University School of Medicine, St. Louis, MO, USA
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Excessive early-life cholesterol exposure may have later-life consequences for nonalcoholic fatty liver disease. J Dev Orig Health Dis 2020; 12:229-236. [PMID: 32290895 DOI: 10.1017/s2040174420000239] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The in utero and immediate postnatal environments are recognized as critical windows of developmental plasticity where offspring are highly susceptible to changes in the maternal metabolic milieu. Maternal hypercholesterolemia (MHC) is a pathological condition characterized by an exaggerated rise in maternal serum cholesterol during pregnancy which can program metabolic dysfunction in offspring, including dysregulation of hepatic lipid metabolism. Although there is currently no established reference range MHC, a loosely defined cutoff point for total cholesterol >280 mg/dL in the third trimester has been suggested. There are several unanswered questions regarding this condition particularly with regard to how the timing of cholesterol exposure influences hepatic lipid dysfunction and the mechanisms through which these adaptations manifest in adulthood. Gestational hypercholesterolemia increased fetal hepatic lipid concentrations and altered lipid regulatory mRNA and protein content. These early changes in hepatic lipid metabolism are evident in the postweaning environment and persist into adulthood. Further, changes to hepatic epigenetic signatures including microRNA (miR) and DNA methylation are observed in utero, at weaning, and are evident in adult offspring. In conclusion, early exposure to cholesterol during critical developmental periods can predispose offspring to the early development of nonalcoholic fatty liver disease (NAFLD) which is characterized by altered regulatory function beginning in utero and persisting throughout the life cycle.
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Tucker B, McClelland RL, Allison MA, Budoff MJ, Wu BJ, Barter PJ, Rye KA, Ong KL. Relationship of fibroblast growth factor 21 levels with inflammation, lipoproteins and non-alcoholic fatty liver disease. Atherosclerosis 2020; 299:38-44. [DOI: 10.1016/j.atherosclerosis.2020.03.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Revised: 02/29/2020] [Accepted: 03/11/2020] [Indexed: 01/14/2023]
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63
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Tramunt B, Smati S, Grandgeorge N, Lenfant F, Arnal JF, Montagner A, Gourdy P. Sex differences in metabolic regulation and diabetes susceptibility. Diabetologia 2020; 63:453-461. [PMID: 31754750 PMCID: PMC6997275 DOI: 10.1007/s00125-019-05040-3] [Citation(s) in RCA: 413] [Impact Index Per Article: 103.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2019] [Accepted: 09/23/2019] [Indexed: 12/14/2022]
Abstract
Gender and biological sex impact the pathogenesis of numerous diseases, including metabolic disorders such as diabetes. In most parts of the world, diabetes is more prevalent in men than in women, especially in middle-aged populations. In line with this, considering almost all animal models, males are more likely to develop obesity, insulin resistance and hyperglycaemia than females in response to nutritional challenges. As summarised in this review, it is now obvious that many aspects of energy balance and glucose metabolism are regulated differently in males and females and influence their predisposition to type 2 diabetes. During their reproductive life, women exhibit specificities in energy partitioning as compared with men, with carbohydrate and lipid utilisation as fuel sources that favour energy storage in subcutaneous adipose tissues and preserve them from visceral and ectopic fat accumulation. Insulin sensitivity is higher in women, who are also characterised by higher capacities for insulin secretion and incretin responses than men; although, these sex advantages all disappear when glucose tolerance deteriorates towards diabetes. Clinical and experimental observations evidence the protective actions of endogenous oestrogens, mainly through oestrogen receptor α activation in various tissues, including the brain, the liver, skeletal muscle, adipose tissue and pancreatic beta cells. However, beside sex steroids, underlying mechanisms need to be further investigated, especially the role of sex chromosomes, fetal/neonatal programming and epigenetic modifications. On the path to precision medicine, further deciphering sex-specific traits in energy balance and glucose homeostasis is indeed a priority topic to optimise individual approaches in type 2 diabetes prevention and treatment.
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Affiliation(s)
- Blandine Tramunt
- Institut des Maladies Métaboliques et Cardiovasculaires (I2MC), UMR1048, Team 9, INSERM/UPS, Université de Toulouse, 1 avenue Jean Poulhès, BP 84225, 31432, Toulouse Cedex 4, France
- Service de Diabétologie, Maladies Métaboliques et Nutrition, CHU de Toulouse, Toulouse, France
| | - Sarra Smati
- Institut des Maladies Métaboliques et Cardiovasculaires (I2MC), UMR1048, Team 9, INSERM/UPS, Université de Toulouse, 1 avenue Jean Poulhès, BP 84225, 31432, Toulouse Cedex 4, France
- Institut National de la Recherche Agronomique (INRA), Toxalim UMR 1331, Toulouse, France
| | - Naia Grandgeorge
- Service de Diabétologie, Maladies Métaboliques et Nutrition, CHU de Toulouse, Toulouse, France
| | - Françoise Lenfant
- Institut des Maladies Métaboliques et Cardiovasculaires (I2MC), UMR1048, Team 9, INSERM/UPS, Université de Toulouse, 1 avenue Jean Poulhès, BP 84225, 31432, Toulouse Cedex 4, France
| | - Jean-François Arnal
- Institut des Maladies Métaboliques et Cardiovasculaires (I2MC), UMR1048, Team 9, INSERM/UPS, Université de Toulouse, 1 avenue Jean Poulhès, BP 84225, 31432, Toulouse Cedex 4, France
| | - Alexandra Montagner
- Institut des Maladies Métaboliques et Cardiovasculaires (I2MC), UMR1048, Team 9, INSERM/UPS, Université de Toulouse, 1 avenue Jean Poulhès, BP 84225, 31432, Toulouse Cedex 4, France
| | - Pierre Gourdy
- Institut des Maladies Métaboliques et Cardiovasculaires (I2MC), UMR1048, Team 9, INSERM/UPS, Université de Toulouse, 1 avenue Jean Poulhès, BP 84225, 31432, Toulouse Cedex 4, France.
- Service de Diabétologie, Maladies Métaboliques et Nutrition, CHU de Toulouse, Toulouse, France.
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64
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Cebola I. Liver gene regulatory networks: Contributing factors to nonalcoholic fatty liver disease. WILEY INTERDISCIPLINARY REVIEWS-SYSTEMS BIOLOGY AND MEDICINE 2020; 12:e1480. [PMID: 32020788 DOI: 10.1002/wsbm.1480] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2019] [Revised: 01/02/2020] [Accepted: 01/03/2020] [Indexed: 12/17/2022]
Abstract
Metabolic diseases such as nonalcoholic fatty liver disease (NAFLD) result from complex interactions between intrinsic and extrinsic factors, including genetics and exposure to obesogenic environments. These risk factors converge in aberrant gene expression patterns in the liver, which are underlined by altered cis-regulatory networks. In homeostasis and in disease states, liver cis-regulatory networks are established by coordinated action of liver-enriched transcription factors (TFs), which define enhancer landscapes, activating broad gene programs with spatiotemporal resolution. Recent advances in DNA sequencing have dramatically expanded our ability to map active transcripts, enhancers and TF cistromes, and to define the 3D chromatin topology that contains these elements. Deployment of these technologies has allowed investigation of the molecular processes that regulate liver development and metabolic homeostasis. Moreover, genomic studies of NAFLD patients and NAFLD models have demonstrated that the liver undergoes pervasive regulatory rewiring in NAFLD, which is reflected by aberrant gene expression profiles. We have therefore achieved an unprecedented level of detail in the understanding of liver cis-regulatory networks, particularly in physiological conditions. Future studies should aim to map active regulatory elements with added levels of resolution, addressing how the chromatin landscapes of different cell lineages contribute to and are altered in NAFLD and NAFLD-associated metabolic states. Such efforts would provide additional clues into the molecular factors that trigger this disease. This article is categorized under: Biological Mechanisms > Metabolism Biological Mechanisms > Regulatory Biology Laboratory Methods and Technologies > Genetic/Genomic Methods.
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Affiliation(s)
- Inês Cebola
- Department of Metabolism, Digestion and Reproduction, Section of Genetics and Genomics, Imperial College London, London, UK
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65
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Marjot T, Moolla A, Cobbold JF, Hodson L, Tomlinson JW. Nonalcoholic Fatty Liver Disease in Adults: Current Concepts in Etiology, Outcomes, and Management. Endocr Rev 2020; 41:5601173. [PMID: 31629366 DOI: 10.1210/endrev/bnz009] [Citation(s) in RCA: 123] [Impact Index Per Article: 30.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Accepted: 10/14/2019] [Indexed: 02/06/2023]
Abstract
Nonalcoholic fatty liver disease (NAFLD) is a spectrum of disease, extending from simple steatosis to inflammation and fibrosis with a significant risk for the development of cirrhosis. It is highly prevalent and is associated with significant adverse outcomes both through liver-specific morbidity and mortality but, perhaps more important, through adverse cardiovascular and metabolic outcomes. It is closely associated with type 2 diabetes and obesity, and both of these conditions drive progressive disease toward the more advanced stages. The mechanisms that govern hepatic lipid accumulation and the predisposition to inflammation and fibrosis are still not fully understood but reflect a complex interplay between metabolic target tissues including adipose and skeletal muscle, and immune and inflammatory cells. The ability to make an accurate assessment of disease stage (that relates to clinical outcome) can also be challenging. While liver biopsy is still regarded as the gold-standard investigative tool, there is an extensive literature on the search for novel noninvasive biomarkers and imaging modalities that aim to accurately reflect the stage of underlying disease. Finally, although no therapies are currently licensed for the treatment of NAFLD, there are interventions that appear to have proven efficacy in randomized controlled trials as well as an extensive emerging therapeutic landscape of new agents that target many of the fundamental pathophysiological processes that drive NAFLD. It is highly likely that over the next few years, new treatments with a specific license for the treatment of NAFLD will become available.
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Affiliation(s)
- Thomas Marjot
- Translational Gastroenterology Unit, NIHR Oxford Biomedical Research Centre, University of Oxford, John Radcliffe Hospital, Oxford, UK.,Oxford Centre for Diabetes, Endocrinology and Metabolism, NIHR Oxford Biomedical Research Centre, University of Oxford, Churchill Hospital, Oxford, UK
| | - Ahmad Moolla
- Oxford Centre for Diabetes, Endocrinology and Metabolism, NIHR Oxford Biomedical Research Centre, University of Oxford, Churchill Hospital, Oxford, UK
| | - Jeremy F Cobbold
- Translational Gastroenterology Unit, NIHR Oxford Biomedical Research Centre, University of Oxford, John Radcliffe Hospital, Oxford, UK
| | - Leanne Hodson
- Oxford Centre for Diabetes, Endocrinology and Metabolism, NIHR Oxford Biomedical Research Centre, University of Oxford, Churchill Hospital, Oxford, UK
| | - Jeremy W Tomlinson
- Oxford Centre for Diabetes, Endocrinology and Metabolism, NIHR Oxford Biomedical Research Centre, University of Oxford, Churchill Hospital, Oxford, UK
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66
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Lonardo A, Nascimbeni F, Ballestri S, Fairweather D, Win S, Than TA, Abdelmalek MF, Suzuki A. Sex Differences in Nonalcoholic Fatty Liver Disease: State of the Art and Identification of Research Gaps. Hepatology 2019; 70:1457-1469. [PMID: 30924946 PMCID: PMC6766425 DOI: 10.1002/hep.30626] [Citation(s) in RCA: 561] [Impact Index Per Article: 112.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2018] [Accepted: 03/19/2019] [Indexed: 12/11/2022]
Abstract
Despite tremendous research advancements in nonalcoholic fatty liver disease (NAFLD), our understanding of sex differences in NAFLD remains insufficient. This review summarizes the current knowledge on sex differences in NAFLD, identifies gaps, and discusses important considerations for future research. The prevalence and severity of NAFLD are higher in men than in women during the reproductive age. However, after menopause, NAFLD occurs at a higher rate in women, suggesting that estrogen is protective. Sex differences also exist for the major risk factors of NAFLD. In general, animal models of NAFLD recapitulate the sex differences observed in patients, with more severe steatosis and steatohepatitis, more proinflammatory/profibrotic cytokines, and a higher incidence of hepatic tumors in male than female subjects. Based on computer modeling, female and male livers are metabolically distinct with unique regulators modulating sex-specific metabolic outcomes. Analysis of the literature reveals that most published clinical and epidemiological studies fail to examine sex differences appropriately. Considering the paucity of data on sex differences and the knowledge that regulators of pathways relevant to current therapeutic targets for NAFLD differ by sex, clinical trials should be designed to test drug efficacy and safety according to sex, age, reproductive stage (i.e., menopause), and synthetic hormone use. Conclusion: Sex differences do exist in the prevalence, risk factors, fibrosis, and clinical outcomes of NAFLD, suggesting that, while not yet incorporated, sex will probably be considered in future practice guidelines; adequate consideration of sex differences, sex hormones/menopausal status, age, and other reproductive information in clinical investigation and gene association studies of NAFLD are needed to fill current gaps and implement precision medicine for patients with NAFLD.
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Affiliation(s)
- Amedeo Lonardo
- Azienda Ospedaliero-Universitaria di Modena, Modena, Italy
| | | | | | - DeLisa Fairweather
- Department of Cardiovascular Medicine, Mayo Clinic, Jacksonville, Florida, USA
| | - Sanda Win
- University of Southern California Research Center for Liver Diseases, Keck School of Medicine, University of Southern California, Los Angeles, USA
| | - Tin A. Than
- University of Southern California Research Center for Liver Diseases, Keck School of Medicine, University of Southern California, Los Angeles, USA
| | - Manal F. Abdelmalek
- Division of Gastroenterology, Duke University Medical Center, Durham, North Carolina, USA
| | - Ayako Suzuki
- Division of Gastroenterology, Duke University Medical Center, Durham, North Carolina, USA,Division of Gastroenterology, Durham VA Medical Center, Durham. North Carolina, USA,Corresponding author: Ayako Suzuki, MD, PhD, MSc, Gastroenterology, Duke University, 40 Duke Medicine Circle, Suite 03107, Durham, NC, 27710, TEL: 919-684-6211, FAX: 919-684-8857,
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67
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Hodson L, Karpe F. Hyperinsulinaemia: does it tip the balance toward intrahepatic fat accumulation? Endocr Connect 2019; 8:R157-R168. [PMID: 31581129 PMCID: PMC6826170 DOI: 10.1530/ec-19-0350] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Accepted: 09/26/2019] [Indexed: 12/12/2022]
Abstract
In health, the liver is metabolically flexible over the course of the day, as it undertakes a multitude of physiological processes including the regulation of intrahepatic and systemic glucose and lipid levels. The liver is the first organ to receive insulin and through a cascade of complex metabolic processes, insulin not only plays a key role in the intrahepatic regulation of glucose and lipid metabolism, but also in the regulation of systemic glucose and lipid concentrations. Thus, when intrahepatic insulin signalling becomes aberrant then this may lead to perturbations in intrahepatic metabolic processes that have the potential to impact on metabolic health. For example, obesity is associated with intrahepatic fat accumulation (known as nonalcoholic liver disease (NAFLD)) and hyperinsulinaemia, the latter as a result of insulin hypersecretion or impaired hepatic insulin extraction. Although insulin signalling directly alters intra- and extrahepatic metabolism, the regulation of hepatic glucose and fatty acid metabolism is also indirectly driven by substrate availability. Here we discuss the direct and indirect effects of insulin on intrahepatic processes such as the synthesis of fatty acids and peripherally regulating the flux of fatty acids to the liver; processes that may play a role in the development of insulin resistance and/or intrahepatocellular triacylglycerol (IHTAG) accumulation in humans.
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Affiliation(s)
- Leanne Hodson
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, University of Oxford and National Institute for Health Research (NIHR) Oxford Biomedical Research Centre (BRC), Oxford University Hospital Trusts, Oxford, UK
| | - Fredrik Karpe
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, University of Oxford and National Institute for Health Research (NIHR) Oxford Biomedical Research Centre (BRC), Oxford University Hospital Trusts, Oxford, UK
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68
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Luukkonen PK, Nick A, Hölttä-Vuori M, Thiele C, Isokuortti E, Lallukka-Brück S, Zhou Y, Hakkarainen A, Lundbom N, Peltonen M, Orho-Melander M, Orešič M, Hyötyläinen T, Hodson L, Ikonen E, Yki-Järvinen H. Human PNPLA3-I148M variant increases hepatic retention of polyunsaturated fatty acids. JCI Insight 2019; 4:127902. [PMID: 31434800 PMCID: PMC6777808 DOI: 10.1172/jci.insight.127902] [Citation(s) in RCA: 92] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Accepted: 07/16/2019] [Indexed: 12/14/2022] Open
Abstract
The common patatin-like phospholipase domain-containing protein 3 (PNPLA3) variant I148M predisposes to nonalcoholic liver disease but not its metabolic sequelae. We compared the handling of labeled polyunsaturated fatty acids (PUFAs) and saturated fatty acids (SFA) in vivo in humans and in cells harboring different PNPLA3 genotypes. In 148M homozygous individuals, triglycerides (TGs) in very low-density lipoproteins (VLDL) were depleted of PUFAs both under fasting and postprandial conditions compared with 148I homozygotes, and the PUFA/SFA ratio in VLDL-TGs was lower relative to the chylomicron precursor pool. In human PNPLA3-148M and PNPLA3-KO cells, PUFA but not SFA incorporation into TGs was increased at the expense of phosphatidylcholines, and under lipolytic conditions, PUFA-containing diacylglycerols (DAGs) accumulated compared with PNPLA3-148I cells. Polyunsaturated TGs were increased, while phosphatidylcholines (PCs) were decreased in the human liver in 148M homozygous individuals as compared with 148I homozygotes. We conclude that human PNPLA3-I148M is a loss-of-function allele that remodels liver TGs in a polyunsaturated direction by impairing hydrolysis/transacylation of PUFAs from DAGs to feed phosphatidylcholine synthesis.
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Affiliation(s)
- Panu K. Luukkonen
- Minerva Foundation Institute for Medical Research, Helsinki, Finland
- Department of Medicine, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Auli Nick
- Minerva Foundation Institute for Medical Research, Helsinki, Finland
- Faculty of Medicine, Department of Anatomy, University of Helsinki, Helsinki, Finland
| | - Maarit Hölttä-Vuori
- Minerva Foundation Institute for Medical Research, Helsinki, Finland
- Faculty of Medicine, Department of Anatomy, University of Helsinki, Helsinki, Finland
| | | | - Elina Isokuortti
- Minerva Foundation Institute for Medical Research, Helsinki, Finland
- Department of Medicine, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Susanna Lallukka-Brück
- Minerva Foundation Institute for Medical Research, Helsinki, Finland
- Department of Medicine, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - You Zhou
- Minerva Foundation Institute for Medical Research, Helsinki, Finland
- Systems Immunity Research Institute, Cardiff University, Cardiff, United Kingdom
- Division of Infection and Immunity, Cardiff University School of Medicine, Cardiff, United Kingdom
| | - Antti Hakkarainen
- Department of Radiology, HUS Medical Imaging Center, Helsinki University Hospital and University of Helsinki, Helsinki, Finland
- Department of Neuroscience and Biomedical Engineering, Aalto University School of Science, Espoo, Finland
| | - Nina Lundbom
- Department of Radiology, HUS Medical Imaging Center, Helsinki University Hospital and University of Helsinki, Helsinki, Finland
| | - Markku Peltonen
- Department of Public Health Solutions, National Institute for Health and Welfare, Helsinki, Finland
| | | | - Matej Orešič
- Turku Centre for Biotechnology, University of Turku and Åbo Akademi University, Turku, Finland
- School of Medical Sciences and
| | | | - Leanne Hodson
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Oxford, United Kingdom
| | - Elina Ikonen
- Minerva Foundation Institute for Medical Research, Helsinki, Finland
- Faculty of Medicine, Department of Anatomy, University of Helsinki, Helsinki, Finland
| | - 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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69
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Raghow R, Dong Q, Elam MB. Phosphorylation dependent proteostasis of sterol regulatory element binding proteins. Biochim Biophys Acta Mol Cell Biol Lipids 2019; 1864:1145-1156. [DOI: 10.1016/j.bbalip.2019.04.015] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Revised: 02/19/2019] [Accepted: 04/28/2019] [Indexed: 12/17/2022]
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Moore MP, Cunningham RP, Kelty TJ, Boccardi LR, Nguyen NY, Booth FW, Rector RS. Ketogenic diet in combination with voluntary exercise impacts markers of hepatic metabolism and oxidative stress in male and female Wistar rats. Appl Physiol Nutr Metab 2019; 45:35-44. [PMID: 31116955 DOI: 10.1139/apnm-2019-0042] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Ketogenic diets (KDs) are shown to benefit hepatic metabolism; however, their effect on the liver when combined with exercise is unknown. We investigated the effects of a KD versus a "western" diet (WD) on markers of hepatic lipid metabolism and oxidative stress in exercising rats. Male and female Wistar rats with access to voluntary running wheels were randomized to 3 groups (n = 8-14 per group): standard chow (SC; 17% fat), WD (42% fat), or KD (90.5% fat) for 7 weeks. Body fat percentage (BF%) was increased in WD and KD versus SC, although KD females displayed lower BF% versus WD (p ≤ 0.05). Liver triglycerides were higher in KD and WD versus SC but were attenuated in KD females versus WD (p ≤ 0.05). KD suppressed hepatic markers of de novo lipogenesis (fatty acid synthase, acetyl coenzyme A carboxylase) and increased markers of mitochondrial biogenesis/content (peroxisome proliferator activated receptor-1α, mitochondrial transcription factor A (TFAM), and citrate synthase activity). KD also increased hepatic glutathione peroxidase 1 and lowered oxidized glutathione. Female rats exhibited elevated hepatic markers of mitochondrial biogenesis (TFAM), mitophagy (light chain 3 II/I ratio, autophagy-related protein 12:5), and cellular energy homeostasis (phosphorylated 5'AMP-activated protein kinase/5'AMP-activated protein kinase) versus males. These data highlight that KD and exercise beneficially impacts hepatic metabolism and oxidative stress and merits further investigation. Novelty KD feeding combined with exercise improved hepatic oxidative stress, suppressed markers of de novo lipogenesis, and increased markers of mitochondrial content versus WD feeding. Males and females responded similarly to combined KD feeding and exercise. Female rats exhibited elevated hepatic markers of autophagy/mitophagy and energy homeostasis compared with male rats.
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Affiliation(s)
- Mary P Moore
- Research Service, Harry S Truman Memorial Veterans Medical Center, Columbia, MO 65201, USA.,Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, MO 65203, USA
| | - Rory P Cunningham
- Research Service, Harry S Truman Memorial Veterans Medical Center, Columbia, MO 65201, USA.,Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, MO 65203, USA
| | - Taylor J Kelty
- Biomedical Sciences, University of Missouri, Columbia, MO 65211, USA
| | - Luigi R Boccardi
- Research Service, Harry S Truman Memorial Veterans Medical Center, Columbia, MO 65201, USA.,Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, MO 65203, USA.,Division of Gastroenterology and Hepatology, University of Missouri, Columbia, MO 65212, USA
| | - Nhu Y Nguyen
- Research Service, Harry S Truman Memorial Veterans Medical Center, Columbia, MO 65201, USA.,Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, MO 65203, USA
| | - Frank W Booth
- Biomedical Sciences, University of Missouri, Columbia, MO 65211, USA
| | - R Scott Rector
- Research Service, Harry S Truman Memorial Veterans Medical Center, Columbia, MO 65201, USA.,Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, MO 65203, USA.,Division of Gastroenterology and Hepatology, University of Missouri, Columbia, MO 65212, USA
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Abstract
Non-alcoholic fatty liver disease encompasses a spectrum of conditions from hepatic steatosis through to cirrhosis; obesity is a known risk factor. The liver plays a major role in regulating fatty acid metabolism and perturbations in intrahepatic processes have potential to impact on metabolic health. It remains unclear why intra-hepatocellular fat starts to accumulate, but it likely involves an imbalance between fatty acid delivery to the liver, fatty acid synthesis and oxidation within the liver and TAG export from the liver. As man spends the majority of the day in a postprandial rather than postabsorptive state, dietary fatty acid intake should be taken into consideration when investigating why intra-hepatic fat starts to accumulate. This review will discuss the impact of the quantity and quality of dietary fatty acids on liver fat accumulation and metabolism, along with some of the potential mechanisms involved. Studies investigating the role of dietary fat in liver fat accumulation, although surprisingly limited, have clearly demonstrated that it is total energy intake, rather than fat intake per se, that is a key mediator of liver fat content; hyperenergetic diets increase liver fat whilst hypoenergetic diets decrease liver fat content irrespective of total fat content. Moreover, there is now, albeit limited evidence emerging to suggest the composition of dietary fat may also play a role in liver fat accumulation, with diets enriched in saturated fat appearing to increase liver fat content to a greater extent when compared with diets enriched in unsaturated fats.
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72
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Emerging awareness on the importance of skeletal muscle in liver diseases: time to dig deeper into mechanisms! Clin Sci (Lond) 2019; 133:465-481. [DOI: 10.1042/cs20180421] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Revised: 01/09/2019] [Accepted: 01/23/2019] [Indexed: 02/07/2023]
Abstract
Abstract
Skeletal muscle is a tissue that represents 30–40% of total body mass in healthy humans and contains up to 75% of total body proteins. It is thus the largest organ in non-obese subjects. The past few years have seen increasing awareness of the prognostic value of appreciating changes in skeletal muscle compartment in various chronic diseases. Hence, a low muscle mass, a low muscle function and muscle fatty infiltration are linked with poor outcomes in many pathological conditions. In particular, an affluent body of evidence links the severity, the complications and mortality of chronic liver disease (CLD) with skeletal muscle depletion. Yet it is still not clear whether low muscle mass is a cause, an aggravating factor, a consequence of the ongoing disease, or an epiphenomenon reflecting general alteration in the critically ill patient. The mechanisms by which the muscle compartment influences disease prognosis are still largely unknown. In addition, whether muscle alterations contribute to liver disease progression is an unanswered question. Here, we first review basic knowledge about muscle compartment to draw a conceptual framework for interpreting skeletal muscle alteration in CLD. We next describe recent literature on muscle wasting in cirrhosis and liver transplantation. We then discuss the implication of skeletal muscle compartment in non-alcoholic fatty liver disease (NAFLD)/non-alcoholic steatohepatitis (NASH), focusing on plausible metabolic disruption in muscle compartment that might participate in NAFLD progression. Finally, we discuss shortcomings and challenges we need to address in the near future prior to designate the muscle compartment as a therapeutic target in CLD.
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73
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Rosqvist F, McNeil CA, Pramfalk C, Parry SA, Low WS, Cornfield T, Fielding BA, Hodson L. Fasting hepatic de novo lipogenesis is not reliably assessed using circulating fatty acid markers. Am J Clin Nutr 2019; 109:260-268. [PMID: 30721918 PMCID: PMC6367991 DOI: 10.1093/ajcn/nqy304] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Accepted: 10/03/2018] [Indexed: 12/18/2022] Open
Abstract
Background Observational studies often infer hepatic de novo lipogenesis (DNL) by measuring circulating fatty acid (FA) markers; however, it remains to be elucidated whether these markers accurately reflect hepatic DNL. Objectives We investigated associations between fasting hepatic DNL and proposed FA markers of DNL in subjects consuming their habitual diet. Methods Fasting hepatic DNL was assessed using 2H2O (deuterated water) in 149 nondiabetic men and women and measuring the synthesis of very low-density lipoprotein triglyceride (VLDL-TG) palmitate. FA markers of blood lipid fractions were determined by gas chromatography. Results Neither the lipogenic index (16:0/18:2n-6) nor the SCD index (16:1n-7/16:0) in VLDL-TG was associated with isotopically assessed DNL (r = 0.13, P = 0.1 and r = -0.08, P = 0.35, respectively). The relative abundances (mol%) of 14:0, 16:0, and 18:0 in VLDL-TG were weakly (r ≤ 0.35) associated with DNL, whereas the abundances of 16:1n-7, 18:1n-7, and 18:1n-9 were not associated. When the cohort was split by median DNL, only the abundances of 14:0 and 18:0 in VLDL-TG could discriminate between subjects having high (11.5%) and low (3.8%) fasting hepatic DNL. Based on a subgroup, FA markers in total plasma TG, plasma cholesteryl esters, plasma phospholipids, and red blood cell phospholipids were generally not associated with DNL. Conclusions The usefulness of circulating FAs as markers of hepatic DNL in healthy individuals consuming their habitual diet is limited due to their inability to discriminate clearly between individuals with low and high fasting hepatic DNL.
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Affiliation(s)
- Fredrik Rosqvist
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, United Kingdom
- Department of Public Health and Caring Sciences, Clinical Nutrition and Metabolism, Uppsala University, Uppsala, Sweden
| | - Catriona A McNeil
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, United Kingdom
| | - Camilla Pramfalk
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, United Kingdom
- Division of Clinical Chemistry, Department of Laboratory Medicine, Karolinska Institute at Karolinska University Hospital Huddinge, Stockholm, Sweden
| | - Sion A Parry
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, United Kingdom
| | - Wee Suan Low
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, United Kingdom
| | - Thomas Cornfield
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, United Kingdom
| | - Barbara A Fielding
- Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom
| | - Leanne Hodson
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, United Kingdom
- Oxford NIHR Biomedical Research Centre, Churchill Hospital, Oxford, United Kingdom
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74
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Young KA, Maturu A, Lorenzo C, Langefeld CD, Wagenknecht LE, Chen YDI, Taylor KD, Rotter JI, Norris JM, Rasouli N. The triglyceride to high-density lipoprotein cholesterol (TG/HDL-C) ratio as a predictor of insulin resistance, β-cell function, and diabetes in Hispanics and African Americans. J Diabetes Complications 2019; 33:118-122. [PMID: 30522790 PMCID: PMC6331279 DOI: 10.1016/j.jdiacomp.2018.10.018] [Citation(s) in RCA: 62] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Revised: 10/29/2018] [Accepted: 10/29/2018] [Indexed: 01/01/2023]
Abstract
OBJECTIVE The TG/HDL-C ratio is used as a marker of insulin resistance (IR) in Caucasians; however, there is limited data in other ethnic groups. We hypothesized that the TG/HDL-C ratio is associated with IR in Hispanics and African Americans (AA). RESEARCH DESIGN AND METHODS Data from the Insulin Resistance Atherosclerosis Family Study was examined for associations between TG/HDL-C ratio and IR, β-cell function and incident diabetes in non-diabetic Hispanics (n = 872, 63% female) and AA (n = 371, 61% female). Insulin sensitivity index (SI) and disposition index (DI) from frequently-sampled intravenous glucose tolerance tests were used as markers of IR and β-cell function respectively. Incident type 2 diabetes was determined by fasting glucose ≥ 126 mg/dl or initiation of anti-hyperglycemia agents over 5 year follow-up. RESULTS Higher TG/HDL-C ratio was associated with IR in Hispanic and AA men and women (P < 0.0002), as well as β-cell function in Hispanic women and AA men and women (P < 0.02). TG/HDL-C predicted incident type 2 diabetes in women (area under the curves 0.703 and 0.795 for Hispanics and AA respectively). CONCLUSIONS Similar to Caucasians, the TG/HDL-C ratio can be used to identify IR in Hispanics and AA, and may predict type 2 diabetes in women.
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Affiliation(s)
- Kendra A Young
- Colorado School of Public Health, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, United States of America
| | - Amita Maturu
- OhioHealth, Columbus, OH 43235, United States of America
| | - Carlos Lorenzo
- Department of Medicine, University of Texas Health Sciences Center, San Antonio, TX 78229, United States of America
| | - Carl D Langefeld
- Center for Public Health Genomics and Department of Biostatistical Sciences, Wake Forest School of Medicine, Winston Salem, NC 27157, United States of America
| | - Lynne E Wagenknecht
- Center for Public Health Genomics and Department of Biostatistical Sciences, Wake Forest School of Medicine, Winston Salem, NC 27157, United States of America
| | - Yii-Der I Chen
- Institute for Translational Genomics and Population Sciences and Department of Pediatrics, Los Angeles Biomedical Research Institute at Harbor-University of California, Los Angeles, CA 90502, United States of America
| | - Kent D Taylor
- Institute for Translational Genomics and Population Sciences and Department of Pediatrics, Los Angeles Biomedical Research Institute at Harbor-University of California, Los Angeles, CA 90502, United States of America
| | - Jerome I Rotter
- Institute for Translational Genomics and Population Sciences and Department of Pediatrics, Los Angeles Biomedical Research Institute at Harbor-University of California, Los Angeles, CA 90502, United States of America
| | - Jill M Norris
- Colorado School of Public Health, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, United States of America
| | - Neda Rasouli
- Division of Endocrinology, Diabetes and Metabolism, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, United States of America; VA Eastern Colorado Health Care System, Denver, CO 80220, United States of America.
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75
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Beaudry KM, Devries MC. Sex-based differences in hepatic and skeletal muscle triglyceride storage and metabolism 1. Appl Physiol Nutr Metab 2019; 44:805-813. [PMID: 30702924 DOI: 10.1139/apnm-2018-0635] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Women and men store lipid differently within the body with men storing more fat in the android region and women storing more fat in the gynoid region. Fat is predominately stored in adipose tissue as triacylglycerides (TG); however, TG are also stored in other tissues including the liver and skeletal muscle. Excess hepatic TG storage, defined as a TG concentration >5% of liver weight and known as nonalcoholic fatty liver disease (NAFLD), is related to the metabolic syndrome. Similarly, elevated skeletal muscle TG, termed intramyocellular lipids (IMCL), are related to insulin resistance in obesity and type II diabetes. Men store more hepatic TG than women and, unsurprisingly, NAFLD is more prevalent in men than women. Women store more IMCL than men, yet type II diabetes risk is not greater, which is likely due to the manner in which women store TG within muscle. Sex-based differences in TG storage between men and women are underpinned by differences in messenger RNA expression, protein content, and enzyme activities of skeletal muscle and hepatic lipid metabolic pathways. Furthermore, women have a greater reliance on lipid during exercise because of upregulation of lipid oxidative pathways. The purpose of this review is to discuss the role of sex in mediating lipid storage and metabolism within skeletal muscle and the liver at rest and during exercise and its relationship with metabolic disease.
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Affiliation(s)
- Kayleigh M Beaudry
- Department of Kinesiology, Faculty of Applied Health Sciences, University of Waterloo, Waterloo, ON N2L 3G1, Canada.,Department of Kinesiology, Faculty of Applied Health Sciences, University of Waterloo, Waterloo, ON N2L 3G1, Canada
| | - Michaela C Devries
- Department of Kinesiology, Faculty of Applied Health Sciences, University of Waterloo, Waterloo, ON N2L 3G1, Canada.,Department of Kinesiology, Faculty of Applied Health Sciences, University of Waterloo, Waterloo, ON N2L 3G1, Canada
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76
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Martin GG, Landrock D, Dangott LJ, McIntosh AL, Kier AB, Schroeder F. Human Liver Fatty Acid Binding Protein-1 T94A Variant, Nonalcohol Fatty Liver Disease, and Hepatic Endocannabinoid System. Lipids 2019; 53:27-40. [PMID: 29488637 DOI: 10.1002/lipd.12008] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Revised: 10/26/2017] [Accepted: 10/31/2017] [Indexed: 12/16/2022]
Abstract
Hepatic endocannabinoids (EC) and their major binding/"chaperone" protein (i.e., liver fatty acid binding protein-1 [FABP1]) are associated with development of nonalcoholic fatty liver (NAFLD) in animal models and humans. Since expression of the highly prevalent human FABP1 T94A variant induces serum lipid accumulation, it is important to determine its impact on hepatic lipid accumulation and the EC system. This issue was addressed in livers from human subjects expressing only wild-type (WT) FABP1 T94T (TT genotype) or T94A variant (TC or CC genotype). WT FABP1 males had lower total lipids (both neutral cholesteryl esters, triacylglycerols) and phospholipids than females. WT FABP1 males' lower lipids correlated with lower levels of the N-acylethanolamide DHEA and 2-monoacylglycerols (2-MAG) (2-OG, 2-PG). T94A expression in males increased the hepatic total lipids (triacylglycerol, cholesteryl ester), which is consistent with their higher level of CB1-potentiating 2-OG and lower antagonistic EPEA. In contrast, in females, T94A expression did not alter the total lipids, neutral lipids, or phospholipids, which is attributable to the higher cannabinoid receptor-1 (CB1) agonist arachidonoylethanolamide (AEA) and its CB1-potentiator OEA being largely offset by reduced potentiating 2-OG and increased antagonistic EPEA. Taken together, these findings indicate that T94A-induced alterations in the hepatic EC system contribute at least in part to the hepatic accumulation of lipids associated with NAFLD, especially in males.
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Affiliation(s)
- Gregory G Martin
- Department of Physiology and Pharmacology, Texas A&M University, College Station, TX, 77843-4466, USA
| | - Danilo Landrock
- Department of Pathobiology, Texas A&M University, College Station, TX, 77843-4467, USA
| | - Lawrence J Dangott
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, 77843-2128, USA
| | - Avery L McIntosh
- Department of Physiology and Pharmacology, Texas A&M University, College Station, TX, 77843-4466, USA
| | - Ann B Kier
- Department of Pathobiology, Texas A&M University, College Station, TX, 77843-4467, USA
| | - Friedhelm Schroeder
- Department of Physiology and Pharmacology, Texas A&M University, College Station, TX, 77843-4466, USA
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77
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Pinnick KE, Gunn PJ, Hodson L. Measuring Human Lipid Metabolism Using Deuterium Labeling: In Vivo and In Vitro Protocols. Methods Mol Biol 2019; 1862:83-96. [PMID: 30315461 DOI: 10.1007/978-1-4939-8769-6_6] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Stable isotopes are powerful tools for tracing the metabolic fate of molecules in the human body. In this chapter, we focus on the use of deuterium (2H), a stable isotope of hydrogen, in the study of human lipid metabolism within the liver in vivo in humans and in vitro using hepatocyte cellular models. The measurement of de novo lipogenesis (DNL) will be focussed on, as the synthesis of fatty acids, specifically palmitate, has been gathering momentum as being implicated in cellular dysfunction, which may be involved in the development of non-alcoholic fatty liver disease (NAFLD). Therefore, this chapter focusses specifically on the use of 2H2O (heavy water) to measure hepatic DNL.
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Affiliation(s)
- Katherine E Pinnick
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Churchill Hospital, University of Oxford, Oxford, UK.
| | - Pippa J Gunn
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Churchill Hospital, University of Oxford, Oxford, UK
| | - Leanne Hodson
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Churchill Hospital, University of Oxford, Oxford, UK.
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78
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Hepatic fatty acid synthesis and partitioning: the effect of metabolic and nutritional state. Proc Nutr Soc 2018; 78:126-134. [PMID: 30457067 DOI: 10.1017/s0029665118002653] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
When we consume dietary fat, a series of complex metabolic processes ensures that fatty acids are absorbed, transported around the body and used/stored appropriately. The liver is a central metabolic organ within the human body and has a major role in regulating fat and carbohydrate metabolism. Studying hepatic metabolism in human subjects is challenging; the use of stable isotope tracers and measurement of particles or molecules secreted by the liver such as VLDL-TAG and 3-hydroxybutyrate offers the best insight into postprandial hepatic fatty acid metabolism in human subjects. Diet derived fatty acids are taken up by the liver and mix with fatty acids coming from the lipolysis of adipose tissue, and those already present in the liver (cytosolic TAG) and fatty acids synthesised de novo within the liver from non-lipid precursors (known as de novo lipogenesis). Fatty acids are removed from the liver by secretion as VLDL-TAG and oxidation. Perturbations in these processes have the potential to impact on metabolic health. Whether fatty acids are partitioned towards oxidation or esterification pathways appears to be dependent on a number of metabolic factors; not least ambient insulin concentrations. Moreover, along with the phenotype and lifestyle factors (e.g. habitual diet) of an individual, it is becoming apparent that the composition of the diet (macronutrient and fatty acid composition) may play pivotal roles in determining if intra-hepatic fat accumulates, although what remains to be elucidated is the influence these nutrients have on intra-hepatic fatty acid synthesis and partitioning.
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79
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Arisqueta L, Navarro-Imaz H, Labiano I, Rueda Y, Fresnedo O. High-fat diet overfeeding promotes nondetrimental liver steatosis in female mice. Am J Physiol Gastrointest Liver Physiol 2018; 315:G772-G780. [PMID: 30095299 DOI: 10.1152/ajpgi.00022.2018] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
High-fat diet (HFD) feeding or leptin-deficient mice are extensively used as models resembling features of human nonalcoholic fatty liver disease (NAFLD). The concurrence of experimental factors as fat content and source or total caloric intake leads to prominent differences in the development of the hepatic steatosis and related disturbances. In this work, we characterized the hepatic lipid accumulation induced by HFD in wild-type (WT) and ob/ ob mice with the purpose of differentiating adaptations to HFD from those specific of increased overfeeding due to leptin deficiency-associated hyperphagia. Given that most published works have been done in male models, we used female mice with the aim of increasing the body of evidence regarding NAFLD in female subjects. HFD promoted liver lipid accumulation only in the hyperphagic strain. Nevertheless, a decrease of lipid droplet-associated cholesteryl ester (CE) in both WT and obese animals was observed. These changes were accompanied by an improvement in the profile of lipoproteins that transport cholesterol and liver function markers in plasma from ob/ ob mice and a lower hepatic index. Using primary hepatocytes from female mice, overaccumulation of CE induced by 0.4 mM oleic acid reversed in the presence of a specific Takeda G protein-coupled bile acid receptor agonist. Nevertheless, hepatocytes from male mice were not responsive. This study suggests that enterohepatic circulation of bile acids might be one of the factors that can affect sex dimorphism in NAFLD development, which underlines the importance of including female models in the NAFLD research field. NEW & NOTEWORTHY This work provides new insight into the use of high-fat diet as a model to induce nonalcoholic fatty liver disease in wild-type and ob/ ob female mice. We show that high-fat diet induces steatosis only in ob/ ob mice while, surprisingly, several health indicators improve. Noteworthy, experiments with primary hepatocytes from male and female mice show that they express Takeda G protein-coupled bile acid receptor and that it and bile acid enterohepatic circulation might be accountable for sex dimorphism in nonalcoholic fatty liver disease development.
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Affiliation(s)
- Lino Arisqueta
- Facultad de Ciencias Naturales y Ambientales, Universidad Internacional SEK , Quito , Ecuador
| | - Hiart Navarro-Imaz
- Lipids and Liver Research Group, Department of Physiology, Faculty of Medicine and Nursing, University of the Basque Country UPV/EHU, Leioa, Spain
| | - Ibone Labiano
- Department of Liver and Gastrointestinal Diseases, Health Research Institute, Biodonostia, Spain
| | - Yuri Rueda
- Lipids and Liver Research Group, Department of Physiology, Faculty of Medicine and Nursing, University of the Basque Country UPV/EHU, Leioa, Spain
| | - Olatz Fresnedo
- Lipids and Liver Research Group, Department of Physiology, Faculty of Medicine and Nursing, University of the Basque Country UPV/EHU, Leioa, Spain
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80
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Lee J, Ha J, Jo K, Lim DJ, Lee JM, Chang SA, Kang MI, Cha BY, Kim MH. Male-specific association between subclinical hypothyroidism and the risk of non-alcoholic fatty liver disease estimated by hepatic steatosis index: Korea National Health and Nutrition Examination Survey 2013 to 2015. Sci Rep 2018; 8:15145. [PMID: 30310098 PMCID: PMC6181925 DOI: 10.1038/s41598-018-32245-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Accepted: 08/30/2018] [Indexed: 02/08/2023] Open
Abstract
Non-alcoholic fatty liver disease (NAFLD) is a prevalent liver disease encompassing a broad spectrum of pathologic changes in the liver. Metabolic derangements are suggested to be main causes of NAFLD. As thyroid hormone is a main regulator of energy metabolism, there may be a link between NAFLD and thyroid function. In previous studies, the association between NAFLD and thyroid function was not conclusive. The aim of this study was to clarify the relationship between NAFLD and thyroid function, focusing on subclinical hypothyroidism, using nationwide survey data representing the Korean population. NAFLD was defined as a hepatic steatosis index of 36 or higher. Based on the analysis of nationwide representative data, subclinical hypothyroidism was related to a high risk of NAFLD in males, but not in females. Our study showed that thyroid function might play a substantial role in the development of NAFLD, especially in males. Further study to elucidate the underlying mechanism of gender specific association of mild thyroid dysfunction and NAFLD would be required.
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Affiliation(s)
- Jeongmin Lee
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Jeonghoon Ha
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Kwanhoon Jo
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Dong-Jun Lim
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Jung-Min Lee
- Division of Endocrinology and Metabolism, Department of Internal Medicine, St. Paul's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Sang-Ah Chang
- Division of Endocrinology and Metabolism, Department of Internal Medicine, St. Paul's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Moo-Il Kang
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Bong-Yun Cha
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Min-Hee Kim
- Division of Endocrinology and Metabolism, Department of Internal Medicine, St. Paul's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea.
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81
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Sex-specific differences in hepatic steatosis in obese spontaneously hypertensive (SHROB) rats. Biol Sex Differ 2018; 9:40. [PMID: 30201044 PMCID: PMC6131947 DOI: 10.1186/s13293-018-0202-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Accepted: 08/31/2018] [Indexed: 12/12/2022] Open
Abstract
Background Patients with metabolic syndrome, who are characterized by co-existence of insulin resistance, hypertension, hyperlipidemia, and obesity, are also prone to develop non-alcoholic fatty liver disease (NAFLD). Although the prevalence and severity of NAFLD is significantly greater in men than women, the mechanisms by which gender modulates the pathogenesis of hepatic steatosis are poorly defined. The obese spontaneously hypertensive (SHROB) rats represent an attractive model of metabolic syndrome without overt type 2 diabetes. Although pathological manifestation caused by the absence of a functional leptin receptor has been extensively studied in SHROB rats, it is unknown whether these animals elicited sex-specific differences in the development of hepatic steatosis. Methods We compared hepatic pathology in male and female SHROB rats. Additionally, we examined key biochemical and molecular parameters of signaling pathways linked with hyperinsulinemia and hyperlipidemia. Finally, using methods of quantitative polymerase chain reaction (qPCR) and western blot analysis, we quantified expression of 45 genes related to lipid biosynthesis and metabolism in the livers of male and female SHROB rats. Results We show that all SHROB rats developed hepatic steatosis that was accompanied by enhanced expression of SREBP1, SREBP2, ACC1, and FASN proteins. The livers of male rats also elicited higher induction of Pparg, Ppara, Slc2a4, Atox1, Skp1, Angptl3, and Pnpla3 mRNAs. In contrast, the livers of female SHROB rats elicited constitutively higher levels of phosphorylated JNK and AMPK and enhanced expression of Cd36. Conclusion Based on these data, we conclude that the severity of hepatic steatosis in male and female SHROB rats was mainly driven by increased de novo lipogenesis. Moreover, male and female SHROB rats also elicited differential severity of hepatic steatosis that was coupled with sex-specific differences in fatty acid transport and esterification. Electronic supplementary material The online version of this article (10.1186/s13293-018-0202-x) contains supplementary material, which is available to authorized users.
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82
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Sex Differences in Hepatic De Novo Lipogenesis with Acute Fructose Feeding. Nutrients 2018; 10:nu10091263. [PMID: 30205493 PMCID: PMC6164310 DOI: 10.3390/nu10091263] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Revised: 09/05/2018] [Accepted: 09/06/2018] [Indexed: 12/21/2022] Open
Abstract
Dietary free sugars have received much attention over the past few years. Much of the focus has been on the effect of fructose on hepatic de novo lipogenesis (DNL). Therefore the aim of the present study was to investigate the effects of meals high and low in fructose on postprandial hepatic DNL and fatty acid partitioning and dietary fatty acid oxidation. Sixteen healthy adults (eight men, eight women) participated in this randomised cross-over study; study days were separated by a 4-week wash-out period. Hepatic DNL and dietary fatty acid oxidation were assessed using stable-isotope tracer methodology. Consumption of the high fructose meal significantly increased postprandial hepatic DNL to a greater extent than consumption of the low fructose meal and this effect was evident in women but not men. Despite an increase in hepatic DNL, there was no change in dietary fatty acid oxidation. Taken together, our data show that women are more responsive to ingestion of higher amounts of fructose than men and if continued over time this may lead to changes in hepatic fatty acid partitioning and eventually liver fat content.
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83
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Green CJ, Parry SA, Gunn PJ, Ceresa CDL, Rosqvist F, Piché ME, Hodson L. Studying non-alcoholic fatty liver disease: the ins and outs of in vivo, ex vivo and in vitro human models. Horm Mol Biol Clin Investig 2018; 41:/j/hmbci.ahead-of-print/hmbci-2018-0038/hmbci-2018-0038.xml. [PMID: 30098284 DOI: 10.1515/hmbci-2018-0038] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Accepted: 06/22/2018] [Indexed: 02/07/2023]
Abstract
The prevalence of non-alcoholic fatty liver disease (NAFLD) is increasing. Determining the pathogenesis and pathophysiology of human NAFLD will allow for evidence-based prevention strategies, and more targeted mechanistic investigations. Various in vivo, ex situ and in vitro models may be utilised to study NAFLD; but all come with their own specific caveats. Here, we review the human-based models and discuss their advantages and limitations in regards to studying the development and progression of NAFLD. Overall, in vivo whole-body human studies are advantageous in that they allow for investigation within the physiological setting, however, limited accessibility to the liver makes direct investigations challenging. Non-invasive imaging techniques are able to somewhat overcome this challenge, whilst the use of stable-isotope tracers enables mechanistic insight to be obtained. Recent technological advances (i.e. normothermic machine perfusion) have opened new opportunities to investigate whole-organ metabolism, thus ex situ livers can be investigated directly. Therefore, investigations that cannot be performed in vivo in humans have the potential to be undertaken. In vitro models offer the ability to perform investigations at a cellular level, aiding in elucidating the molecular mechanisms of NAFLD. However, a number of current models do not closely resemble the human condition and work is ongoing to optimise culturing parameters in order to recapitulate this. In summary, no single model currently provides insight into the development, pathophysiology and progression across the NAFLD spectrum, each experimental model has limitations, which need to be taken into consideration to ensure appropriate conclusions and extrapolation of findings are made.
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Affiliation(s)
- Charlotte J Green
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, UK
| | - Siôn A Parry
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, UK
| | - Pippa J Gunn
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, UK
| | - Carlo D L Ceresa
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, UK
- Nuffield Department of Surgical Sciences, University of Oxford, Oxford, UK
| | - Fredrik Rosqvist
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, UK
- Department of Public Health and Caring Sciences, Clinical Nutrition and Metabolism, Uppsala University, Uppsala, Sweden
| | - Marie-Eve Piché
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, UK
- Quebec Heart and Lung Institute, Laval University, Quebec, Canada
| | - Leanne Hodson
- University of Oxford, Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, Churchill Hospital,Old Road Headington, Oxford OX3 7LE, United Kingdom of Great Britain and Northern Ireland
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84
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Mardinoglu A, Wu H, Bjornson E, Zhang C, Hakkarainen A, Räsänen SM, Lee S, Mancina RM, Bergentall M, Pietiläinen KH, Söderlund S, Matikainen N, Ståhlman M, Bergh PO, Adiels M, Piening BD, Granér M, Lundbom N, Williams KJ, Romeo S, Nielsen J, Snyder M, Uhlén M, Bergström G, Perkins R, Marschall HU, Bäckhed F, Taskinen MR, Borén J. An Integrated Understanding of the Rapid Metabolic Benefits of a Carbohydrate-Restricted Diet on Hepatic Steatosis in Humans. Cell Metab 2018; 27:559-571.e5. [PMID: 29456073 PMCID: PMC6706084 DOI: 10.1016/j.cmet.2018.01.005] [Citation(s) in RCA: 300] [Impact Index Per Article: 50.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Revised: 12/06/2017] [Accepted: 01/10/2018] [Indexed: 02/07/2023]
Abstract
A carbohydrate-restricted diet is a widely recommended intervention for non-alcoholic fatty liver disease (NAFLD), but a systematic perspective on the multiple benefits of this diet is lacking. Here, we performed a short-term intervention with an isocaloric low-carbohydrate diet with increased protein content in obese subjects with NAFLD and characterized the resulting alterations in metabolism and the gut microbiota using a multi-omics approach. We observed rapid and dramatic reductions of liver fat and other cardiometabolic risk factors paralleled by (1) marked decreases in hepatic de novo lipogenesis; (2) large increases in serum β-hydroxybutyrate concentrations, reflecting increased mitochondrial β-oxidation; and (3) rapid increases in folate-producing Streptococcus and serum folate concentrations. Liver transcriptomic analysis on biopsy samples from a second cohort revealed downregulation of the fatty acid synthesis pathway and upregulation of folate-mediated one-carbon metabolism and fatty acid oxidation pathways. Our results highlight the potential of exploring diet-microbiota interactions for treating NAFLD.
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Affiliation(s)
- Adil Mardinoglu
- Science for Life Laboratory, KTH Royal Institute of Technology, Stockholm, Sweden; Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | - Hao Wu
- Department of Molecular and Clinical Medicine, University of Gothenburg, and Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Elias Bjornson
- Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden; Department of Molecular and Clinical Medicine, University of Gothenburg, and Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Cheng Zhang
- Science for Life Laboratory, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Antti Hakkarainen
- HUS Medical Imaging Center, Radiology, Helsinki University Hospital, University of Helsinki, Helsinki, Finland
| | - Sari M Räsänen
- Research Programs Unit, Diabetes and Obesity, University of Helsinki and Department of Internal Medicine, Helsinki University Hospital, Helsinki, Finland
| | - Sunjae Lee
- Science for Life Laboratory, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Rosellina M Mancina
- Department of Molecular and Clinical Medicine, University of Gothenburg, and Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Mattias Bergentall
- Department of Molecular and Clinical Medicine, University of Gothenburg, and Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Kirsi H Pietiläinen
- Research Programs Unit, Diabetes and Obesity, University of Helsinki and Department of Internal Medicine, Helsinki University Hospital, Helsinki, Finland; Endocrinology, Abdominal Center, Helsinki University Hospital, Helsinki, Finland
| | - Sanni Söderlund
- Research Programs Unit, Diabetes and Obesity, University of Helsinki and Department of Internal Medicine, Helsinki University Hospital, Helsinki, Finland
| | - Niina Matikainen
- Research Programs Unit, Diabetes and Obesity, University of Helsinki and Department of Internal Medicine, Helsinki University Hospital, Helsinki, Finland; Endocrinology, Abdominal Center, Helsinki University Hospital, Helsinki, Finland
| | - Marcus Ståhlman
- Department of Molecular and Clinical Medicine, University of Gothenburg, and Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Per-Olof Bergh
- Department of Molecular and Clinical Medicine, University of Gothenburg, and Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Martin Adiels
- Department of Molecular and Clinical Medicine, University of Gothenburg, and Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Brian D Piening
- Department of Genetics, Stanford University, Stanford, CA 94305, USA
| | - Marit Granér
- Research Programs Unit, Diabetes and Obesity, University of Helsinki and Department of Internal Medicine, Helsinki University Hospital, Helsinki, Finland
| | - Nina Lundbom
- HUS Medical Imaging Center, Radiology, Helsinki University Hospital, University of Helsinki, Helsinki, Finland
| | - Kevin J Williams
- Department of Molecular and Clinical Medicine, University of Gothenburg, and Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Stefano Romeo
- Department of Molecular and Clinical Medicine, University of Gothenburg, and Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Jens Nielsen
- Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | - Michael Snyder
- Department of Genetics, Stanford University, Stanford, CA 94305, USA
| | - Mathias Uhlén
- Science for Life Laboratory, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Göran Bergström
- Department of Molecular and Clinical Medicine, University of Gothenburg, and Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Rosie Perkins
- Department of Molecular and Clinical Medicine, University of Gothenburg, and Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Hanns-Ulrich Marschall
- Department of Molecular and Clinical Medicine, University of Gothenburg, and Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Fredrik Bäckhed
- Department of Molecular and Clinical Medicine, University of Gothenburg, and Sahlgrenska University Hospital, Gothenburg, Sweden.
| | - Marja-Riitta Taskinen
- Research Programs Unit, Diabetes and Obesity, University of Helsinki and Department of Internal Medicine, Helsinki University Hospital, Helsinki, Finland
| | - Jan Borén
- Department of Molecular and Clinical Medicine, University of Gothenburg, and Sahlgrenska University Hospital, Gothenburg, Sweden.
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85
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Lee YH, Kim SH, Kim SN, Kwon HJ, Kim JD, Oh JY, Jung YS. Sex-specific metabolic interactions between liver and adipose tissue in MCD diet-induced non-alcoholic fatty liver disease. Oncotarget 2018; 7:46959-46971. [PMID: 27409675 PMCID: PMC5216916 DOI: 10.18632/oncotarget.10506] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Accepted: 06/30/2016] [Indexed: 02/06/2023] Open
Abstract
Higher susceptibility to metabolic disease in male exemplifies the importance of sexual dimorphism in pathogenesis. We hypothesized that the higher incidence of non-alcoholic fatty liver disease in males involves sex-specific metabolic interactions between liver and adipose tissue. In the present study, we used a methionine-choline deficient (MCD) diet-induced fatty liver mouse model to investigate sex differences in the metabolic response of the liver and adipose tissue. After 2 weeks on an MCD-diet, fatty liver was induced in a sex-specific manner, affecting male mice more severely than females. The MCD-diet increased lipolytic enzymes in the gonadal white adipose tissue (gWAT) of male mice, whereas it increased expression of uncoupling protein 1 and other brown adipocyte markers in the gWAT of female mice. Moreover, gWAT from female mice demonstrated higher levels of oxygen consumption and mitochondrial content compared to gWAT from male mice. FGF21 expression was increased in liver tissue by the MCD diet, and the degree of upregulation was significantly higher in the livers of female mice. The endocrine effect of FGF21 was responsible, in part, for the sex-specific browning of gonadal white adipose tissue. Collectively, these data demonstrated that distinctively female-specific browning of white adipose tissue aids in protecting female mice against MCD diet-induced fatty liver disease.
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Affiliation(s)
- Yun-Hee Lee
- College of Pharmacy, Yonsei University, Incheon, Republic of Korea
| | - Sou Hyun Kim
- College of Pharmacy, Pusan National University, Busan, Republic of Korea
| | - Sang-Nam Kim
- College of Pharmacy, Yonsei University, Incheon, Republic of Korea
| | - Hyun-Jung Kwon
- College of Pharmacy, Yonsei University, Incheon, Republic of Korea
| | - Jeong-Dong Kim
- College of Pharmacy, Yonsei University, Incheon, Republic of Korea
| | - Ji Youn Oh
- College of Pharmacy, Pusan National University, Busan, Republic of Korea
| | - Young-Suk Jung
- College of Pharmacy, Pusan National University, Busan, Republic of Korea
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86
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Ahn SH, Seo DH, Kim SH, Nam MS, Hong S. The relationship between fatty liver index and bone mineral density in Koreans: KNHANES 2010-2011. Osteoporos Int 2018; 29:181-190. [PMID: 29051986 DOI: 10.1007/s00198-017-4257-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Accepted: 10/05/2017] [Indexed: 12/28/2022]
Abstract
UNLABELLED Analyses using a nationally representative cohort have revealed that high fatty liver index (FLI) is associated with low bone mineral density (BMD) regardless of insulin resistance in men, thereby supporting the deteriorated bone metabolism in nonalcoholic fatty liver disease (NAFLD). INTRODUCTION NAFLD is linked to deteriorated bone health. We investigated the association of FLI, a scoring model for NAFLD, with BMD. METHODS This was a population-based, cross-sectional study from the Korea National Health and Nutrition Examination Surveys including 4264 Koreans (1908 men and 2356 women). FLI was calculated using body mass index, waist circumference, serum triglyceride, and gamma-glutamyltranspeptidase level. Insulin resistance was evaluated using the homeostasis model assessment-estimated insulin resistance (HOMA-IR) index. BMD was measured using dual-energy X-ray absorptiometry at the lumbar spine, total hip, femoral neck, and whole body. RESULTS Men had a higher FLI than women, while the HOMA-IR index was similar between men and women. The significant association between FLI and BMD was observed only in men, but not in women. FLI was negatively correlated with total hip, femoral neck, and whole body BMD in men after adjusting for all potential confounders, including HOMA-IR (P < 0.001 to 0.010). Lumbar spine, total hip, femoral neck, and whole body BMD in men showed a decreasing trend as the FLI tertile increased after adjusting for all potential confounders, including HOMA-IR (P for trends < 0.001 to 0.034). In men aged 50 years or older, odds ratios for combined osteopenia and osteoporosis increased across increasing FLI tertiles after adjusting for confounders (P for trends < 0.011 to 0.029). CONCLUSION NAFLD is associated with low bone density regardless of insulin resistance in men. These findings suggest an undiscovered direct link between liver and bone that increases the risk of osteoporosis in men with NAFLD.
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Affiliation(s)
- S H Ahn
- Division of Endocrinology and Metabolism, Inha University Hospital, Inha University School of Medicine, Incheon, 22332, Republic of Korea
| | - D H Seo
- Division of Endocrinology and Metabolism, Inha University Hospital, Inha University School of Medicine, Incheon, 22332, Republic of Korea
| | - S H Kim
- Division of Endocrinology and Metabolism, Inha University Hospital, Inha University School of Medicine, Incheon, 22332, Republic of Korea
| | - M-S Nam
- Division of Endocrinology and Metabolism, Inha University Hospital, Inha University School of Medicine, Incheon, 22332, Republic of Korea
| | - S Hong
- Division of Endocrinology and Metabolism, Inha University Hospital, Inha University School of Medicine, Incheon, 22332, Republic of Korea.
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87
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Piché ME, Parry SA, Karpe F, Hodson L. Chylomicron-Derived Fatty Acid Spillover in Adipose Tissue: A Signature of Metabolic Health? J Clin Endocrinol Metab 2018; 103:25-34. [PMID: 29099975 PMCID: PMC5761493 DOI: 10.1210/jc.2017-01517] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Accepted: 10/27/2017] [Indexed: 12/29/2022]
Abstract
Context and Objectives Spillover of fatty acids (FAs) into the plasma nonesterified fatty acid (NEFA) pool, because of an inability of adipose tissue (AT) to accommodate sufficient fat uptake, has been suggested to contribute to obesity-related insulin resistance. Using specific labeling techniques, we compared the proportion of spillover-derived NEFA across a range of adiposity. Participants and Methods Seventy-one healthy men and women were fed a mixed meal (40 g fat) containing [U13C]palmitate to assess the contribution of chylomicron-derived spillover FAs. To investigate subcutaneous abdominal-specific spillover, arteriovenous difference and stable-isotope methodologies were used in substudy (six men, six women). Results Chylomicron-derived FA spillover was higher in individuals with a BMI <25 kg/m2 (n = 18) compared with those with a BMI ≥25 kg/m2 (n = 53) (22.2 ± 1.6% vs 18.6 ± 0.7%, P = 0.02). Women had higher chylomicron-derived FA spillover than age- and BMI-matched men (21.9 ± 1.1% vs 15.0 ± 1.6%, P = 0.001). Assessing spillover across subcutaneous abdominal AT showed higher proportions in women than in men (28.5 ± 6.1% vs 9.9 ± 1.3%, P = 0.01). Conclusion There is a considerable degree of spillover FA into the systemic NEFA pool in the postprandial state; this process is greater and more dynamic in lean individuals and women. Contrary to general perception, spillover of chylomicron-derived FA into systemic circulation is a physiologically normal feature most easily observed in people with a higher capacity for clearance of plasma triglycerides, but does not appear to be a pathway providing excess NEFA in obesity.
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Affiliation(s)
- Marie-Eve Piché
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford OX3 7LE, United Kingdom
- Quebec Heart and Lung Institute, Laval University, Quebec G1V 4G5, Canada
| | - Siôn A. Parry
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford OX3 7LE, United Kingdom
| | - Fredrik Karpe
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford OX3 7LE, United Kingdom
- National Institute for Health Research Oxford Biomedical Research Centre, Oxford University Hospital Trusts, Oxford OX3 9DU, United Kingdom
| | - Leanne Hodson
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford OX3 7LE, United Kingdom
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88
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Soares AF, Paz-Montoya J, Lei H, Moniatte M, Gruetter R. Sexual dimorphism in hepatic lipids is associated with the evolution of metabolic status in mice. NMR IN BIOMEDICINE 2017; 30:e3761. [PMID: 28661066 DOI: 10.1002/nbm.3761] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Revised: 05/16/2017] [Accepted: 05/16/2017] [Indexed: 05/28/2023]
Abstract
Ectopic lipid accumulation in the liver is implicated in metabolic disease in an age- and sex-dependent manner. The role of hepatic lipids has been well established within the scope of metabolic insults in mice, but has been insufficiently characterized under standard housing conditions, where age-related metabolic alterations are known to occur. We studied a total of 10 male and 10 female mice longitudinally. At 3, 7 and 11 months of age, non-invasive 1 H-magnetic resonance spectroscopy (1 H-MRS) was used to monitor hepatic lipid content (HLC) and fatty acid composition in vivo, and glucose homeostasis was assessed with glucose and insulin challenges. At the end of the study, hepatic lipids were comprehensively characterized by nuclear magnetic resonance (NMR) and liquid chromatography-mass spectrometric analyses of liver tissue samples. In males, HLC increased from 1.4 ± 0.1% at 3 months to 2.9 ± 0.3% at 7 months (p < 0.01) and 2.7 ± 0.3% at 11 months (p < 0.05), in correlation with fasting insulin levels (p < 0.01, r = 0.51) and parameters from the insulin tolerance test (ITT; p < 0.001, r = -0.69 versus area under the curve; p < 0.01, r = -0.57 versus blood glucose drop at 1 h post-ITT; p < 0.01, r = 0.55 versus blood glucose at 3 h post-ITT). The metabolic performance of females remained the same throughout the study, and HLC was higher than that of males at 3 months (2.7 ± 0.2%, p < 0.01), but comparable at 7 months (2.2 ± 0.2%) and 11 months (2.2 ± 0.1%). Strong sexual dimorphism in bioactive lipid species, including diacylglycerols (higher in males, p < 0.0001), phosphatidylinositols (higher in females, p < 0.001) and omega-3 polyunsaturated fatty acids (higher in females, p < 0.01), was found to be in good correlation with metabolic scores at 11 months. Therefore, in mice housed under standard conditions, sex-specific composition of bioactive lipids is associated with metabolic protection in females, whose metabolic performance was independent of hepatic cytosolic lipid content.
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Affiliation(s)
- Ana Francisca Soares
- École Polytechnique Fédérale de Lausanne, Laboratory for Functional and Metabolic Imaging (LIFMET), Lausanne, VD, Switzerland
| | - Jonathan Paz-Montoya
- École Polytechnique Fédérale de Lausanne, Proteomics Core Facility (PCF), Lausanne, VD, Switzerland
| | - Hongxia Lei
- Center for Biomedical Imaging (CIBM), Lausanne VD, Switzerland and University of Geneva, Department of Radiology, Geneva, Switzerland
| | - Marc Moniatte
- École Polytechnique Fédérale de Lausanne, Proteomics Core Facility (PCF), Lausanne, VD, Switzerland
| | - Rolf Gruetter
- École Polytechnique Fédérale de Lausanne, Laboratory for Functional and Metabolic Imaging (LIFMET), Lausanne, VD, Switzerland
- Center for Biomedical Imaging (CIBM), Lausanne VD, Switzerland and University of Geneva, Department of Radiology, Geneva, Switzerland
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89
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NAFL screening score: A basic score identifying ultrasound-diagnosed non-alcoholic fatty liver. Clin Chim Acta 2017; 475:44-50. [PMID: 28964832 DOI: 10.1016/j.cca.2017.09.020] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Revised: 07/09/2017] [Accepted: 09/26/2017] [Indexed: 12/25/2022]
Abstract
BACKGROUND Several non-invasive diagnostic scores for non-alcoholic fatty liver (NAFL) have been developed, but the clinical application is limited because of their complexity. AIM To develop and validate an easy-to-calculate scoring system to identify ultrasound-diagnosed NAFL. METHODS 48,489 patients from 2 centers were included in this study. Multivariable logistic regression models were employed for model development. Ultrasonography was applied to diagnose NAFL. The selected variables were assigned an integer score proportional to the estimated coefficient from the logistic regression analysis, namely NAFL Screening Score (NSS). The ability of the NSS to identify NAFL was assessed by analyzing the area under the receiver operating characteristic curve (AUROC) and was tested in an independent validation cohort. Additionally, the performance of NSS was compared with existing models. RESULTS NSS was developed as a basic score comprising of age, body mass index (BMI), triglyceride (TG), ALT/AST, fasting plasma glucose (FPG) and uric acid (UA) in both sexes. NSS showed a relatively good discriminative power (AUROC=0.825 for males, 0.861 for females in the validation cohort) in comparison with other models. The optimal cut-off point was 32 for males and 29 for females. CONCLUSION We developed and validated NSS, an easy-to-use score sheet identify ultrasound-diagnosed NAFL. NSS may be clinically useful for initial diagnosing NAFL.
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90
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Parry SA, Hodson L. Influence of dietary macronutrients on liver fat accumulation and metabolism. J Investig Med 2017; 65:1102-1115. [PMID: 28947639 PMCID: PMC5749316 DOI: 10.1136/jim-2017-000524] [Citation(s) in RCA: 88] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/08/2017] [Indexed: 02/07/2023]
Abstract
The liver is a principal metabolic organ within the human body and has a major role in regulating carbohydrate, fat, and protein metabolism. With increasing rates of obesity, the prevalence of non-alcoholic fatty liver disease (NAFLD) is growing. It remains unclear why NAFLD, which is now defined as the hepatic manifestation of the metabolic syndrome, develops but lifestyle factors such as diet (ie, total calorie and specific nutrient intakes), appear to play a key role. Here we review the available observational and intervention studies that have investigated the influence of dietary macronutrients on liver fat content. Findings from observational studies are conflicting with some reporting that relative to healthy controls, patients with NAFLD consume diets higher in total fat/saturated fatty acids, whilst others find they consume diets higher in carbohydrates/sugars. From the limited number of intervention studies that have been undertaken, a consistent finding is a hypercaloric diet, regardless of whether the excess calories have been provided either as fat, sugar, or both, increases liver fat content. In contrast, a hypocaloric diet decreases liver fat content. Findings from both hyper- and hypo-caloric feeding studies provide some suggestion that macronutrient composition may also play a role in regulating liver fat content and this is supported by data from isocaloric feeding studies; fatty acid composition and/or carbohydrate content/type appear to influence whether there is accrual of liver fat or not. The mechanisms by which specific macronutrients, when consumed as part of an isocaloric diet, cause a change in liver fat remain to be fully elucidated.
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Affiliation(s)
- Siôn A Parry
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, UK
| | - Leanne Hodson
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, UK
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91
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Gut-Liver Axis Derangement in Non-Alcoholic Fatty Liver Disease. CHILDREN-BASEL 2017; 4:children4080066. [PMID: 28767077 PMCID: PMC5575588 DOI: 10.3390/children4080066] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/13/2017] [Revised: 07/18/2017] [Accepted: 07/21/2017] [Indexed: 02/06/2023]
Abstract
Non-alcoholic fatty liver disease (NAFLD) is the most frequent type of chronic liver disease in the pediatric age group, paralleling an obesity pandemic. A “multiple-hit” hypothesis has been invoked to explain its pathogenesis. The “first hit” is liver lipid accumulation in obese children with insulin resistance. In the absence of significant lifestyle modifications leading to weight loss and increased physical activity, other factors may act as “second hits” implicated in liver damage progression leading to more severe forms of inflammation and hepatic fibrosis. In this regard, the gut–liver axis (GLA) seems to play a central role. Principal players are the gut microbiota, its bacterial products, and the intestinal barrier. A derangement of GLA (namely, dysbiosis and altered intestinal permeability) may promote bacteria/bacterial product translocation into portal circulation, activation of inflammation via toll-like receptors signaling in hepatocytes, and progression from simple steatosis to non-alcoholic steato-hepatitis (NASH). Among other factors a relevant role has been attributed to the farnesoid X receptor, a nuclear transcriptional factor activated from bile acids chemically modified by gut microbiota (GM) enzymes. The individuation and elucidation of GLA derangement in NAFLD pathomechanisms is of interest at all ages and especially in pediatrics to identify new therapeutic approaches in patients recalcitrant to lifestyle changes. Specific targeting of gut microbiota via pre-/probiotic supplementation, feces transplantation, and farnesoid X receptor modulation appear promising.
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92
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McCullough A, Previs S, Kasumov T. Stable isotope-based flux studies in nonalcoholic fatty liver disease. Pharmacol Ther 2017; 181:22-33. [PMID: 28720429 DOI: 10.1016/j.pharmthera.2017.07.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease and is associated with the worldwide epidemics of obesity, diabetes and cardiovascular diseases. NAFLD ranges from benign fat accumulation in the liver (steatosis) to non-alcoholic steatohepatitis (NASH), and cirrhosis which can progress to hepatocellular carcinoma and liver failure. Mass spectrometry and magnetic resonance spectroscopy-coupled stable isotope-based flux studies provide new insights into the understanding of NAFLD pathogenesis and the disease progression. This review focuses mainly on the utilization of mass spectrometry-based methods for the understanding of metabolic abnormalities in the different stages of NAFLD. For example, stable isotope-based flux studies demonstrated multi-organ insulin resistance, dysregulated glucose, lipids and lipoprotein metabolism in patients with NAFLD. We also review recent developments in the stable isotope-based technologies for the study of mitochondrial dysfunction, oxidative stress and fibrogenesis in NAFLD. We highlight the limitations of current methodologies, discuss the emerging areas of research in this field, and future directions for the applications of stable isotopes to study NAFLD and its complications.
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Affiliation(s)
- Arthur McCullough
- Department of Gastroenterology & Hepatology, Cleveland Clinic, Cleveland, OH, USA
| | | | - Takhar Kasumov
- Department of Gastroenterology & Hepatology, Cleveland Clinic, Cleveland, OH, USA; Department of Pharmaceutical Sciences, College of Pharmacy, Northeast Ohio Medical University, Rootstown, OH, USA.
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93
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Hodson L, Bhatia L, Scorletti E, Smith DE, Jackson NC, Shojaee-Moradie F, Umpleby M, Calder PC, Byrne CD. Docosahexaenoic acid enrichment in NAFLD is associated with improvements in hepatic metabolism and hepatic insulin sensitivity: a pilot study. Eur J Clin Nutr 2017; 71:973-979. [PMID: 28294174 PMCID: PMC5474320 DOI: 10.1038/ejcn.2017.9] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Revised: 01/13/2017] [Accepted: 01/17/2017] [Indexed: 12/12/2022]
Abstract
Background/Objective: Treatment of subjects with non-alcoholic fatty liver disease (NAFLD) with omega-3 polyunsaturated fatty acids (FAs) suggests high levels of docosahexaenoic acid (DHA) tissue enrichment decrease liver fat content. We assessed whether changes in erythrocyte DHA enrichment (as a surrogate marker of changes in tissue enrichment) were associated with alterations in hepatic de novo lipogenesis (DNL), postprandial FA partitioning and hepatic and peripheral insulin sensitivity in a sub-study of the WELCOME trial (Wessex Evaluation of fatty Liver and Cardiovascular markers in NAFLD (non-alcoholic fatty liver disease) with OMacor thErapy). Subjects/Methods: Sixteen participants were randomised to 4 g/day EPA+DHA (n=8) or placebo (n=8) for 15–18 months and underwent pre- and post-intervention measurements. Fasting and postprandial hepatic FA metabolism was assessed using metabolic substrates labelled with stable-isotope tracers (2H2O and [U13C]palmitate). Insulin sensitivity was measured by a stepped hyperinsulinaemic-euglycaemic clamp using deuterated glucose. Participants were stratified according to change in DHA erythrocyte enrichment (< or ⩾2% post intervention). Results: Nine participants were stratified to DHA⩾2% (eight randomised to EPA+DHA and one to placebo) and seven to the DHA<2% group (all placebo). Compared with individuals with erythrocyte <2% change in DHA abundance, those with ⩾2% enrichment had significant improvements in hepatic insulin sensitivity, reduced fasting and postprandial plasma triglyceride concentrations, decreased fasting hepatic DNL, as well as greater appearance of 13C from dietary fat into plasma 3-hydroxybutyrate (all P<0.05). Conclusions: The findings from our pilot study indicate that individuals who achieved a change in erythrocyte DHA enrichment ⩾2% show favourable changes in hepatic FA metabolism and insulin sensitivity, which may contribute to decreasing hepatic fat content.
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Affiliation(s)
- L Hodson
- Oxford Centre for Diabetes, Endocrinology and Metabolism (OCDEM), Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - L Bhatia
- Human Development and Health Academic Unit, Southampton, UK
| | - E Scorletti
- Human Development and Health Academic Unit, Southampton, UK.,NIHR Southampton Biomedical Research Centre, University Hospital Southampton NHS Foundation Trust and University of Southampton, Southampton, UK
| | - D E Smith
- Human Development and Health Academic Unit, Southampton, UK.,NIHR Southampton Biomedical Research Centre, University Hospital Southampton NHS Foundation Trust and University of Southampton, Southampton, UK
| | - N C Jackson
- Diabetes and Metabolic Medicine, Department of Nutritional Sciences, University of Surrey, Guildford, UK
| | - F Shojaee-Moradie
- Diabetes and Metabolic Medicine, Department of Nutritional Sciences, University of Surrey, Guildford, UK
| | - M Umpleby
- Diabetes and Metabolic Medicine, Department of Nutritional Sciences, University of Surrey, Guildford, UK
| | - P C Calder
- Human Development and Health Academic Unit, Southampton, UK.,NIHR Southampton Biomedical Research Centre, University Hospital Southampton NHS Foundation Trust and University of Southampton, Southampton, UK
| | - C D Byrne
- Human Development and Health Academic Unit, Southampton, UK.,NIHR Southampton Biomedical Research Centre, University Hospital Southampton NHS Foundation Trust and University of Southampton, Southampton, UK
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Mann JP, Feldstein AE, Nobili V. Update on lipid species and paediatric nonalcoholic fatty liver disease. Curr Opin Clin Nutr Metab Care 2017; 20:110-116. [PMID: 27906700 DOI: 10.1097/mco.0000000000000346] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
PURPOSE OF REVIEW To describe the recent advances in our understanding of fatty acids and lipids in paediatric nonalcoholic fatty liver disease (NAFLD) and their future implications. RECENT FINDINGS Data have been accumulated to suggest that ceramides are the main drivers of hepatic insulin resistance in NAFLD, and inhibition of ceramide synthesis improves histology in mice.Saturated fatty acids formed by de novo lipogenesis generate increased lipotoxicity compared with dietary-derived saturated fatty acids.Hepatic lipogenesis and associated insulin resistance have been found to be influenced by several novel proteins, including E2F1, cyclic AMP response element binding protein transcriptional coactivator 2, Raptor, and eukaryotic initiation factor 6. There are encouraging data from animal models that modulation of these could be therapeutic targets.Human and animal metabolomics and lipidomics data have been used to generate a lipid signature for NAFLD and nonalcoholic steatohepatitis. Serum lipidomics appears to correlate with hepatic lipidomics.Therapeutic trials of polyunsaturated fatty acids in children have had mixed results, with some reductions in noninvasive biomarkers. SUMMARY Multiple new pathways for drug targets have been identified, and use of lipidomics is likely to become a noninvasive method for assessing disease. However, much of the data for paediatric NAFLD are extrapolated from adult or animal studies.
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Affiliation(s)
- Jake P Mann
- aDepartment of Paediatrics, University of Cambridge, Cambridge, UK bDepartment of Pediatric Gastroenterology, University of California San Diego (UCSD) cRady Children's Hospital, San Diego, California, USA dHepatometabolic Unit eLiver Research Unit, Bambino Gesu Hospital, IRCCS, Rome, Italy
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95
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Abstract
Ketone body metabolism is a central node in physiological homeostasis. In this review, we discuss how ketones serve discrete fine-tuning metabolic roles that optimize organ and organism performance in varying nutrient states and protect from inflammation and injury in multiple organ systems. Traditionally viewed as metabolic substrates enlisted only in carbohydrate restriction, observations underscore the importance of ketone bodies as vital metabolic and signaling mediators when carbohydrates are abundant. Complementing a repertoire of known therapeutic options for diseases of the nervous system, prospective roles for ketone bodies in cancer have arisen, as have intriguing protective roles in heart and liver, opening therapeutic options in obesity-related and cardiovascular disease. Controversies in ketone metabolism and signaling are discussed to reconcile classical dogma with contemporary observations.
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Affiliation(s)
- Patrycja Puchalska
- Center for Metabolic Origins of Disease, Sanford Burnham Prebys Medical Discovery Institute, Orlando, FL 32827, USA
| | - Peter A Crawford
- Center for Metabolic Origins of Disease, Sanford Burnham Prebys Medical Discovery Institute, Orlando, FL 32827, USA.
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96
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Abstract
PURPOSE OF REVIEW Experimental evidences are strong for a role of long-chain saturated fatty acids in the development of insulin resistance and type 2 diabetes. Ectopic accretion of triglycerides in lean organs is a characteristic of prediabetes and type 2 diabetes and has been linked to end-organ complications. The contribution of disordered dietary fatty acid (DFA) metabolism to lean organ overexposure and lipotoxicity is still unclear, however. DFA metabolism is very complex and very difficult to study in vivo in humans. RECENT FINDINGS We have recently developed a novel imaging method using PET with oral administration of 14-R,S-F-fluoro-6-thia-heptadecanoic acid (FTHA) to quantify organ-specific DFA partitioning. Our studies thus far confirmed impaired storage of DFA per volume of fat mass in abdominal adipose tissues of individuals with prediabetes. They also highlighted the increased channeling of DFA toward the heart, associated with subclinical reduction in cardiac systolic and diastolic function in individuals with prediabetes. SUMMARY In the present review, we summarize previous work on DFA metabolism in healthy and prediabetic states and discuss these in the light of our novel findings using PET imaging of DFA metabolism. We herein provide an integrated view of abnormal organ-specific DFA partitioning in prediabetes in humans.
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Affiliation(s)
- Christophe Noll
- Division of Endocrinology, Department of Medicine, Centre de recherche du CHUS, Université de Sherbrooke, Sherbrooke, Quebec, Canada
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97
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Wesolowski SR, El Kasmi KC, Jonscher KR, Friedman JE. Developmental origins of NAFLD: a womb with a clue. Nat Rev Gastroenterol Hepatol 2017; 14:81-96. [PMID: 27780972 PMCID: PMC5725959 DOI: 10.1038/nrgastro.2016.160] [Citation(s) in RCA: 160] [Impact Index Per Article: 22.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Changes in the maternal environment leading to an altered intrauterine milieu can result in subtle insults to the fetus, promoting increased lifetime disease risk and/or disease acceleration in childhood and later in life. Particularly worrisome is that the prevalence of NAFLD is rapidly increasing among children and adults, and is being diagnosed at increasingly younger ages, pointing towards an early-life origin. A wealth of evidence, in humans and non-human primates, suggests that maternal nutrition affects the placenta and fetal tissues, leading to persistent changes in hepatic metabolism, mitochondrial function, the intestinal microbiota, liver macrophage activation and susceptibility to NASH postnatally. Deleterious exposures in utero include fetal hypoxia, increased nutrient supply, inflammation and altered gut microbiota that might produce metabolic clues, including fatty acids, metabolites, endotoxins, bile acids and cytokines, which prime the infant liver for NAFLD in a persistent manner and increase susceptibility to NASH. Mechanistic links to early disease pathways might involve shifts in lipid metabolism, mitochondrial dysfunction, pioneering gut microorganisms, macrophage programming and epigenetic changes that alter the liver microenvironment, favouring liver injury. In this Review, we discuss how maternal, fetal, neonatal and infant exposures provide developmental clues and mechanisms to help explain NAFLD acceleration and increased disease prevalence. Mechanisms identified in clinical and preclinical models suggest important opportunities for prevention and intervention that could slow down the growing epidemic of NAFLD in the next generation.
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Affiliation(s)
| | - Karim C. El Kasmi
- Department of Pediatrics, Section of Gastroenterology, Hepatology and Nutrition, University of Colorado
| | | | - Jacob E. Friedman
- Department of Pediatrics, Section of Neonatology, University of Colorado,Department of Medicine, Division of Endocrinology, Metabolism, and Diabetes, University of Colorado, Anschutz Medical Campus, 12801 East 17th Avenue, MS 8106, Aurora, Colorado 80045, USA
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98
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Paglialunga S, Dehn CA. Clinical assessment of hepatic de novo lipogenesis in non-alcoholic fatty liver disease. Lipids Health Dis 2016; 15:159. [PMID: 27640119 PMCID: PMC5027077 DOI: 10.1186/s12944-016-0321-5] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Accepted: 08/30/2016] [Indexed: 02/07/2023] Open
Abstract
Non-alcoholic fatty liver disease (NAFLD) is heralded as the next big global epidemic. Hepatic de novo lipogenesis (DNL), the synthesis of new fatty acids from non-lipid sources, is thought to play a pivotal role in the development of NAFLD. While there is currently no NAFLD-specific therapeutic agent available, pharmaceutical drugs aimed at reducing hepatic fat accretion may prove to be a powerful ally in the treatment and management of this disease. With a focus on NAFLD, the present review summarizes current techniques examining DNL from a clinical perspective, and describes the merits and limitations of three commonly used assays; stable-label isotope tracer studies, fatty acid indexes and indirect calorimetry as non-invasive measures of hepatic DNL. Finally, the application of DNL assessments in the pharmacological and nutraceutical treatment of NAFLD/NASH is summarized. In a clinical research setting, measures of DNL are an important marker in the development of anti-NAFLD treatments.
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Affiliation(s)
- Sabina Paglialunga
- Global Clinical Research, Celerion, 2420 West Baseline Road, Tempe, AZ, 85283, USA.
| | - Clayton A Dehn
- Global Clinical Research, Celerion, 2420 West Baseline Road, Tempe, AZ, 85283, USA.,Current affiliation: Umbrella Corporation, San Antonio, TX, USA
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99
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Pramfalk C, Pavlides M, Banerjee R, McNeil CA, Neubauer S, Karpe F, Hodson L. Fasting Plasma Insulin Concentrations Are Associated With Changes in Hepatic Fatty Acid Synthesis and Partitioning Prior to Changes in Liver Fat Content in Healthy Adults. Diabetes 2016; 65:1858-67. [PMID: 27207513 DOI: 10.2337/db16-0236] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Accepted: 04/12/2016] [Indexed: 11/13/2022]
Abstract
Resistance to the action of insulin affects fatty acid delivery to the liver, fatty acid synthesis and oxidation within the liver, and triglyceride export from the liver. To understand the metabolic consequences of hepatic fatty acid synthesis, partitioning, oxidation, and net liver fat content in the fasted and postprandial states, we used stable-isotope tracer methodologies to study healthy men and women with varying degrees of insulin resistance before and after consumption of a mixed meal. Subjects were classified as being normoinsulinemic (NI) (fasting plasma insulin <11.2 mU/L, n = 18) or hyperinsulinemic (HI) (fasting plasma insulin >11.2 mU/L, n = 19). Liver fat content was similar between HI and NI individuals, despite HI subjects having marginally more visceral fat. However, de novo lipogenesis was higher and fatty acid oxidation was lower in HI individuals compared with NI subjects. These data suggest that metabolic pathways promoting fat accumulation are enhanced in HI but, paradoxically, without any significant effect on liver fat content when observed in healthy people. This is likely to be explained by increased triglyceride secretion as observed by hypertriglyceridemia.
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Affiliation(s)
- Camilla Pramfalk
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, U.K
| | - Michael Pavlides
- Oxford Centre for Clinical Magnetic Resonance Research, University of Oxford, Oxford, U.K. Translational Gastroenterology Unit, John Radcliffe Hospital, Oxford, U.K
| | - Rajarshi Banerjee
- Oxford Centre for Clinical Magnetic Resonance Research, University of Oxford, Oxford, U.K
| | - Catriona A McNeil
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, U.K
| | - Stefan Neubauer
- Oxford Centre for Clinical Magnetic Resonance Research, University of Oxford, Oxford, U.K
| | - Fredrik Karpe
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, U.K. National Institute for Health Research Oxford Biomedical Research Centre, Oxford University Hospital Trusts, Oxford, U.K
| | - Leanne Hodson
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, U.K.
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