51
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Yano K, Yamaguchi K, Seko Y, Okishio S, Ishiba H, Tochiki N, Takahashi A, Kataoka S, Okuda K, Liu Y, Fujii H, Umemura A, Moriguchi M, Okanoue T, Itoh Y. Hepatocyte-specific fibroblast growth factor 21 overexpression ameliorates high-fat diet-induced obesity and liver steatosis in mice. J Transl Med 2022; 102:281-289. [PMID: 34732847 DOI: 10.1038/s41374-021-00680-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2021] [Revised: 09/11/2021] [Accepted: 09/15/2021] [Indexed: 11/09/2022] Open
Abstract
Fibroblast growth factor (FGF) 21 is an endocrine growth factor mainly secreted by the liver in response to a ketogenic diet and alcohol consumption. FGF21 signaling requires co-receptor β-klotho (KLB) co-acting with FGF receptors, which has pleiotropic metabolic effects, including induced hepatic fatty acid oxidation and ketogenesis, in human and animal models of obesity. We examined the hepatocyte-specific enhancer/promoter of FGF21 expression plasmids in high-fat diet-fed mice for 12 weeks. Hydrodynamic injection for FGF21 delivery every 6 weeks sustained high circulating levels of FGF21, resulting in marked reductions in body weight, epididymal fat mass, insulin resistance, and liver steatosis. FGF21-induced lipolysis in the adipose tissue enabled the liver to be flooded with fat-derived FFAs. The hepatic expression of Glut2 and Bdh1 was upregulated, whereas that of gluconeogenesis-related genes, G6p and Pepck, and lipogenesis-related genes, Srebp-1 and Srebp-2, was significantly suppressed. FGF21 induced the phosphorylation of AMPK at Thr172 and Raptor at ser792 and suppressed that of mTOR at ser2448, which downregulated mTORC1 signaling and reduced IRS-1 phosphorylation at ser1101. Finally, in the skeletal muscle, FGF21 increased Glut4 and Mct2, a membrane protein that acts as a carrier for ketone bodies. Enzymes for ketone body catabolism (Scot) and citrate cycle (Cs, Idh3a), and a marker of regenerating muscle (myogenin) were also upregulated via increased KLB expression. Thus, FGF21-induced lipolysis was continuously induced by a high-fat diet and fat-derived FFAs might cause liver damage. Hepatic fatty acid oxidation and ketone body synthesis may act as hepatic FFAs' disposal mechanisms and contribute to improved liver steatosis. Liver-derived ketone bodies might be used for energy in the skeletal muscle. The potential FGF21-related crosstalk between the liver and extraliver organs is a promising strategy to prevent and treat metabolic syndrome-related nonalcoholic steatohepatitis.
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Affiliation(s)
- Kota Yano
- Molecular Gastroenterology and Hepatology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Kanji Yamaguchi
- Molecular Gastroenterology and Hepatology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan.
| | - Yuya Seko
- Molecular Gastroenterology and Hepatology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Shinya Okishio
- Molecular Gastroenterology and Hepatology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Hiroshi Ishiba
- Molecular Gastroenterology and Hepatology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Nozomi Tochiki
- Molecular Gastroenterology and Hepatology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Aya Takahashi
- Molecular Gastroenterology and Hepatology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Seita Kataoka
- Molecular Gastroenterology and Hepatology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Keiichiroh Okuda
- Molecular Gastroenterology and Hepatology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Yu Liu
- Molecular Gastroenterology and Hepatology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Hideki Fujii
- Molecular Gastroenterology and Hepatology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Atsushi Umemura
- Molecular Gastroenterology and Hepatology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Michihisa Moriguchi
- Molecular Gastroenterology and Hepatology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Takeshi Okanoue
- Department of Gastroenterology & Hepatology, Saiseikai Suita Hospital, Osaka, Japan
| | - Yoshito Itoh
- Molecular Gastroenterology and Hepatology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
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52
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Gallego-Durán R, Albillos A, Ampuero J, Arechederra M, Bañares R, Blas-García A, Berná G, Caparrós E, Delgado TC, Falcón-Pérez JM, Francés R, Fernández-Barrena MG, Graupera I, Iruzubieta P, Nevzorova YA, Nogueiras R, Macías RIR, Marín F, Sabio G, Soriano G, Vaquero J, Cubero FJ, Gracia-Sancho J. Metabolic-associated fatty liver disease: from simple steatosis towards liver cirrhosis and potential complications. Proceedings of the Third Translational Hepatology Meeting, endorsed by the Spanish Association for the Study of the Liver (AEEH). GASTROENTEROLOGIA Y HEPATOLOGIA 2022; 45:724-734. [DOI: 10.1016/j.gastrohep.2022.02.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Accepted: 02/21/2022] [Indexed: 11/28/2022]
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53
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Important Functions and Molecular Mechanisms of Mitochondrial Redox Signaling in Pulmonary Hypertension. Antioxidants (Basel) 2022; 11:antiox11030473. [PMID: 35326123 PMCID: PMC8944689 DOI: 10.3390/antiox11030473] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Revised: 02/23/2022] [Accepted: 02/24/2022] [Indexed: 12/13/2022] Open
Abstract
Mitochondria are important organelles that act as a primary site to produce reactive oxygen species (ROS). Additionally, mitochondria play a pivotal role in the regulation of Ca2+ signaling, fatty acid oxidation, and ketone synthesis. Dysfunction of these signaling molecules leads to the development of pulmonary hypertension (PH), atherosclerosis, and other vascular diseases. Features of PH include vasoconstriction and pulmonary artery (PA) remodeling, which can result from abnormal proliferation, apoptosis, and migration of PA smooth muscle cells (PASMCs). These responses are mediated by increased Rieske iron–sulfur protein (RISP)-dependent mitochondrial ROS production and increased mitochondrial Ca2+ levels. Mitochondrial ROS and Ca2+ can both synergistically activate nuclear factor κB (NF-κB) to trigger inflammatory responses leading to PH, right ventricular failure, and death. Evidence suggests that increased mitochondrial ROS and Ca2+ signaling leads to abnormal synthesis of ketones, which play a critical role in the development of PH. In this review, we discuss some of the recent findings on the important interactive role and molecular mechanisms of mitochondrial ROS and Ca2+ in the development and progression of PH. We also address the contributions of NF-κB-dependent inflammatory responses and ketone-mediated oxidative stress due to abnormal regulation of mitochondrial ROS and Ca2+ signaling in PH.
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54
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Ragavan M, McLeod MA, Rushin A, Merritt ME. Detecting de novo Hepatic Ketogenesis Using Hyperpolarized [2- 13C] Pyruvate. Front Physiol 2022; 13:832403. [PMID: 35197867 PMCID: PMC8859440 DOI: 10.3389/fphys.2022.832403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Accepted: 01/14/2022] [Indexed: 11/28/2022] Open
Abstract
The role of ketones in metabolic health has progressed over the past two decades, moving from what was perceived as a simple byproduct of fatty acid oxidation to a central player in a multiplicity of disease states. Previous work with hyperpolarized (HP) 13C has shown that ketone production can be detected when using precursors that labeled acetyl-CoA at the C1 position, often in tissues that are not normally recognized as ketogenic. Here, we assay metabolism of HP [2-13C]pyruvate in the perfused mouse liver, a classic metabolic testbed where nutritional conditions can be precisely controlled. Livers perfused with long-chain fatty acids or the medium-chain fatty acid octanoate showed no evidence of ketogenesis in the 13C spectrum. In contrast, addition of dichloroacetate, a potent inhibitor of pyruvate dehydrogenase kinase, resulted in significant production of both acetoacetate and 3-hydroxybutyrate from the pyruvate precursor. This result indicates that ketones are readily produced from carbohydrates, but only in the case where pyruvate dehydrogenase activity is upregulated.
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Affiliation(s)
| | | | | | - Matthew E. Merritt
- Department of Biochemistry and Molecular Biology, College of Medicine, University of Florida, Gainesville, FL, United States
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55
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Pindozzi F, Socci C, Bissolati M, Marchi M, Devecchi E, Saibene A, Conte C. Role of nutritional ketosis in the improvement of metabolic parameters following bariatric surgery. World J Diabetes 2022; 13:54-64. [PMID: 35070059 PMCID: PMC8771267 DOI: 10.4239/wjd.v13.i1.54] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2021] [Revised: 06/29/2021] [Accepted: 01/05/2022] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Ketone bodies (KB) might act as potential metabolic modulators besides serving as energy substrates. Bariatric metabolic surgery (BMS) offers a unique opportunity to study nutritional ketosis, as acute postoperative caloric restriction leads to increased lipolysis and circulating free fatty acids.
AIM To characterize the relationship between KB production, weight loss (WL) and metabolic changes following BMS.
METHODS For this retrospective study we enrolled male and female subjects aged 18-65 years who underwent BMS at a single Institution. Data on demographics, anthropometrics, body composition, laboratory values and urinary KB were collected.
RESULTS Thirty-nine patients had data available for analyses [74.4% women, mean age 46.5 ± 9.0 years, median body mass index 41.0 (38.5; 45.4) kg/m2, fat mass 45.2% ± 6.2%, 23.1% had diabetes, 43.6% arterial hypertension and 74.4% liver steatosis]. At 46.0 ± 13.6 d post-surgery, subjects had lost 12.0% ± 3.6% of pre-operative weight. Sixty-nine percent developed ketonuria. Those with nutritional ketosis were significantly younger [42.9 (37.6; 50.7) years vs 51.9 (48.3; 59.9) years, P = 0.018], and had significantly lower fasting glucose [89.5 (82.5; 96.3) mg/dL vs 96.0 (91.0; 105.3) mg/dL, P = 0.025] and triglyceride levels [108.0 (84.5; 152.5) mg/dL vs 152.0 (124.0; 186.0) mg/dL, P = 0.045] vs those with ketosis. At 6 mo, percent WL was greater in those with postoperative ketosis (-27.5% ± 5.1% vs 23.8% ± 4.3%, P = 0.035). Urinary KBs correlated with percent WL at 6 and 12 mo. Other metabolic changes were similar.
CONCLUSION Our data support the hypothesis that subjects with worse metabolic status have reduced ketogenic capacity and, thereby, exhibit a lower WL following BMS.
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Affiliation(s)
- Fioralba Pindozzi
- Unità di Chirurgia Generale Provinciale, Ospedale del Delta, Lagosanto (FE) 44023, Italy
| | - Carlo Socci
- Transplant and Metabolic/Bariatric Surgery Unit, IRCCS Ospedale San Raffaele, Milan 20132, Italy
| | - Massimiliano Bissolati
- Transplant and Metabolic/Bariatric Surgery Unit, IRCCS Ospedale San Raffaele, Milan 20132, Italy
| | - Monica Marchi
- Department of General Medicine, Diabetes and Endocrinology, IRCCS Ospedale San Raffaele, Milan 20132, Italy
| | - Elisabetta Devecchi
- Department of General Medicine, Diabetes and Endocrinology, IRCCS Ospedale San Raffaele, Milan 20132, Italy
| | - Alessandro Saibene
- Department of General Medicine, Diabetes and Endocrinology, IRCCS Ospedale San Raffaele, Milan 20132, Italy
| | - Caterina Conte
- Department of Human Sciences and Promotion of the Quality of Life, San Raffaele Open University, Rome 00166, Italy
- Department of Endocrinology, Nutrition and Metabolic Diseases, IRCCS MultiMedica, Milan 20099, Italy
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56
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Rahim M, Ragavan M, Deja S, Merritt ME, Burgess SC, Young JD. INCA 2.0: A tool for integrated, dynamic modeling of NMR- and MS-based isotopomer measurements and rigorous metabolic flux analysis. Metab Eng 2022; 69:275-285. [PMID: 34965470 PMCID: PMC8789327 DOI: 10.1016/j.ymben.2021.12.009] [Citation(s) in RCA: 35] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Revised: 12/17/2021] [Accepted: 12/22/2021] [Indexed: 01/03/2023]
Abstract
Metabolic flux analysis (MFA) combines experimental measurements and computational modeling to determine biochemical reaction rates in live biological systems. Advancements in analytical instrumentation, such as nuclear magnetic resonance (NMR) spectroscopy and mass spectrometry (MS), have facilitated chemical separation and quantification of isotopically enriched metabolites. However, no software packages have been previously described that can integrate isotopomer measurements from both MS and NMR analytical platforms and have the flexibility to estimate metabolic fluxes from either isotopic steady-state or dynamic labeling experiments. By applying physiologically relevant cardiac and hepatic metabolic models to assess NMR isotopomer measurements, we herein test and validate new modeling capabilities of our enhanced flux analysis software tool, INCA 2.0. We demonstrate that INCA 2.0 can simulate and regress steady-state 13C NMR datasets from perfused hearts with an accuracy comparable to other established flux assessment tools. Furthermore, by simulating the infusion of three different 13C acetate tracers, we show that MFA based on dynamic 13C NMR measurements can more precisely resolve cardiac fluxes compared to isotopically steady-state flux analysis. Finally, we show that estimation of hepatic fluxes using combined 13C NMR and MS datasets improves the precision of estimated fluxes by up to 50%. Overall, our results illustrate how the recently added NMR data modeling capabilities of INCA 2.0 can enable entirely new experimental designs that lead to improved flux resolution and can be applied to a wide range of biological systems and measurement time courses.
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Affiliation(s)
- Mohsin Rahim
- Department of Chemical and Biomolecular, Nashville, TN, 37212, USA
| | - Mukundan Ragavan
- Department of Biochemistry and Molecular Biology, University of Florida College of Medicine, Gainesville, FL, USA
| | - Stanislaw Deja
- Center for Human Nutrition, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Matthew E Merritt
- Department of Biochemistry and Molecular Biology, University of Florida College of Medicine, Gainesville, FL, USA
| | - Shawn C Burgess
- Center for Human Nutrition, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Jamey D Young
- Department of Chemical and Biomolecular, Nashville, TN, 37212, USA; Department of Molecular Physiology and Biophysics, Vanderbilt University, School of Engineering, Nashville, TN, 37212, USA.
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57
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Zhang XJ, She ZG, Wang J, Sun D, Shen LJ, Xiang H, Cheng X, Ji YX, Huang YP, Li PL, Yang X, Cheng Y, Ma JP, Wang HP, Hu Y, Hu F, Tian S, Tian H, Zhang P, Zhao GN, Wang L, Hu ML, Yang Q, Zhu LH, Cai J, Yang J, Zhang X, Ma X, Xu Q, Touyz RM, Liu PP, Loomba R, Wang Y, Li H. Multiple omics study identifies an interspecies conserved driver for nonalcoholic steatohepatitis. Sci Transl Med 2021; 13:eabg8117. [PMID: 34910546 DOI: 10.1126/scitranslmed.abg8117] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
[Figure: see text].
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Affiliation(s)
- Xiao-Jing Zhang
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan 430060, China.,Institute of Model Animal of Wuhan University, Wuhan 430071, China.,School of Basic Medical Sciences, Wuhan University, Wuhan 430071, China
| | - Zhi-Gang She
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan 430060, China.,Institute of Model Animal of Wuhan University, Wuhan 430071, China
| | - Junyong Wang
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan 430060, China.,Institute of Model Animal of Wuhan University, Wuhan 430071, China
| | - Dating Sun
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan 430060, China.,Institute of Model Animal of Wuhan University, Wuhan 430071, China
| | - Li-Jun Shen
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan 430060, China.,Institute of Model Animal of Wuhan University, Wuhan 430071, China
| | - Hui Xiang
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan 430060, China.,Institute of Model Animal of Wuhan University, Wuhan 430071, China
| | - Xu Cheng
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan 430060, China.,Institute of Model Animal of Wuhan University, Wuhan 430071, China
| | - Yan-Xiao Ji
- Institute of Model Animal of Wuhan University, Wuhan 430071, China.,School of Basic Medical Sciences, Wuhan University, Wuhan 430071, China
| | - Yong-Ping Huang
- Institute of Model Animal of Wuhan University, Wuhan 430071, China.,College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Peng-Long Li
- Institute of Model Animal of Wuhan University, Wuhan 430071, China.,School of Basic Medical Sciences, Wuhan University, Wuhan 430071, China
| | - Xia Yang
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan 430060, China.,Institute of Model Animal of Wuhan University, Wuhan 430071, China
| | - Yanjie Cheng
- Institute of Model Animal of Wuhan University, Wuhan 430071, China.,Medical Science Research Center, Zhongnan Hospital of Wuhan University, Wuhan 430071, China
| | - Jun-Peng Ma
- Institute of Model Animal of Wuhan University, Wuhan 430071, China.,School of Basic Medical Sciences, Wuhan University, Wuhan 430071, China
| | - Hai-Ping Wang
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan 430060, China.,Institute of Model Animal of Wuhan University, Wuhan 430071, China
| | - Yufeng Hu
- Institute of Model Animal of Wuhan University, Wuhan 430071, China.,Medical Science Research Center, Zhongnan Hospital of Wuhan University, Wuhan 430071, China
| | - Fengjiao Hu
- Institute of Model Animal of Wuhan University, Wuhan 430071, China.,Medical Science Research Center, Zhongnan Hospital of Wuhan University, Wuhan 430071, China
| | - Song Tian
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan 430060, China.,Institute of Model Animal of Wuhan University, Wuhan 430071, China
| | - Han Tian
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan 430060, China.,Institute of Model Animal of Wuhan University, Wuhan 430071, China
| | - Peng Zhang
- Institute of Model Animal of Wuhan University, Wuhan 430071, China.,School of Basic Medical Sciences, Wuhan University, Wuhan 430071, China
| | - Guang-Nian Zhao
- Institute of Model Animal of Wuhan University, Wuhan 430071, China.,Medical Science Research Center, Zhongnan Hospital of Wuhan University, Wuhan 430071, China
| | - Lin Wang
- Department of Hepatic Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, China
| | - Man-Li Hu
- Institute of Model Animal of Wuhan University, Wuhan 430071, China.,Medical Science Research Center, Zhongnan Hospital of Wuhan University, Wuhan 430071, China
| | - Qin Yang
- Institute of Model Animal of Wuhan University, Wuhan 430071, China.,Medical Science Research Center, Zhongnan Hospital of Wuhan University, Wuhan 430071, China
| | - Li-Hua Zhu
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan 430060, China.,Institute of Model Animal of Wuhan University, Wuhan 430071, China
| | - Jingjing Cai
- Department of Cardiology, The Third Xiangya Hospital, Central South University, Changsha 410013, China
| | - Juan Yang
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan 430060, China.,Institute of Model Animal of Wuhan University, Wuhan 430071, China
| | - Xin Zhang
- Institute of Model Animal of Wuhan University, Wuhan 430071, China
| | - Xinliang Ma
- Department of Emergency Medicine, Thomas Jefferson University, Philadelphia, PA 19004, USA
| | - Qingbo Xu
- Centre for Clinic Pharmacology, The William Harvey Research Institute, Queen Mary University of London, London SE5 9NU, UK
| | - Rhian M Touyz
- British Heart Foundation Chair in Cardiovascular Medicine, and Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow G12 8TA, UK
| | - Peter P Liu
- Division of Cardiology, Department of Medicine, University of Ottawa Heart Institute, Ottawa, Ontario K1Y 4W7, Canada
| | - Rohit Loomba
- NAFLD Research Center, Division of Gastroenterology and Epidemiology, University of California, San Diego, San Diego, CA 92093, USA
| | - Yibin Wang
- Department of Anesthesiology, Cardiovascular Research Laboratories, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Hongliang Li
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan 430060, China.,Institute of Model Animal of Wuhan University, Wuhan 430071, China.,School of Basic Medical Sciences, Wuhan University, Wuhan 430071, China.,Medical Science Research Center, Zhongnan Hospital of Wuhan University, Wuhan 430071, China
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58
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Fernández-Verdejo R, Malo-Vintimilla L, Gutiérrez-Pino J, López-Fuenzalida A, Olmos P, Irarrazaval P, Galgani JE. Similar Metabolic Health in Overweight/Obese Individuals With Contrasting Metabolic Flexibility to an Oral Glucose Tolerance Test. Front Nutr 2021; 8:745907. [PMID: 34869522 PMCID: PMC8637191 DOI: 10.3389/fnut.2021.745907] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Accepted: 10/13/2021] [Indexed: 01/14/2023] Open
Abstract
Background: Low metabolic flexibility (MetF) may be an underlying factor for metabolic health impairment. Individuals with low MetF are thus expected to have worse metabolic health than subjects with high MetF. Therefore, we aimed to compare metabolic health in individuals with contrasting MetF to an oral glucose tolerance test (OGTT). Methods: In individuals with excess body weight, we measured MetF as the change in respiratory quotient (RQ) from fasting to 1 h after ingestion of a 75-g glucose load (i.e., OGTT). Individuals were then grouped into low and high MetF (Low-MetF n = 12; High-MetF n = 13). The groups had similar body mass index, body fat, sex, age, and maximum oxygen uptake. Metabolic health markers (clinical markers, insulin sensitivity/resistance, abdominal fat, and intrahepatic fat) were compared between groups. Results: Fasting glucose, triglycerides (TG), and high-density lipoprotein (HDL) were similar between groups. So were insulin sensitivity/resistance, visceral, and intrahepatic fat. Nevertheless, High-MetF individuals had higher diastolic blood pressure, a larger drop in TG concentration during the OGTT, and a borderline significant (P = 0.05) higher Subcutaneous Adipose Tissue (SAT). Further, compared to Low-MetF, High-MetF individuals had an about 2-fold steeper slope for the relationship between SAT and fat mass index. Conclusion: Individuals with contrasting MetF to an OGTT had similar metabolic health. Yet High-MetF appears related to enhanced circulating TG clearance and enlarged subcutaneous fat.
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Affiliation(s)
- Rodrigo Fernández-Verdejo
- Carrera de Nutrición y Dietética, Departamento de Ciencias de la Salud, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile.,Laboratorio de Fisiología del Ejercicio y Metabolismo (LABFEM), Escuela de Kinesiología, Facultad de Medicina, Universidad Finis Terrae, Santiago, Chile
| | - Lorena Malo-Vintimilla
- Departamento de Nutrición, Diabetes y Metabolismo, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Juan Gutiérrez-Pino
- Departamento de Nutrición, Diabetes y Metabolismo, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Antonio López-Fuenzalida
- Carrera de Kinesiología, Departamento de Ciencias de la Salud, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile.,Disciplinary Department of Kinesiology, Faculty of Health Science, Universidad de Playa Ancha, Valparaíso, Chile
| | - Pablo Olmos
- Departamento de Nutrición, Diabetes y Metabolismo, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Pablo Irarrazaval
- Departamento de Ingeniería Eléctrica e Instituto de Ingeniería Biológica y Médica, Escuelas de Ingeniería, Medicina y Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Jose E Galgani
- Carrera de Nutrición y Dietética, Departamento de Ciencias de la Salud, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile.,Departamento de Nutrición, Diabetes y Metabolismo, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
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59
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Hoene M, Kappler L, Kollipara L, Hu C, Irmler M, Bleher D, Hoffmann C, Beckers J, Hrabě de Angelis M, Häring HU, Birkenfeld AL, Peter A, Sickmann A, Xu G, Lehmann R, Weigert C. Exercise prevents fatty liver by modifying the compensatory response of mitochondrial metabolism to excess substrate availability. Mol Metab 2021; 54:101359. [PMID: 34695608 PMCID: PMC8671118 DOI: 10.1016/j.molmet.2021.101359] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 10/07/2021] [Accepted: 10/15/2021] [Indexed: 02/06/2023] Open
Abstract
Objective Liver mitochondria adapt to high-calorie intake. We investigated how exercise alters the early compensatory response of mitochondria, thus preventing fatty liver disease as a long-term consequence of overnutrition. Methods We compared the effects of a steatogenic high-energy diet (HED) for six weeks on mitochondrial metabolism of sedentary and treadmill-trained C57BL/6N mice. We applied multi-OMICs analyses to study the alterations in the proteome, transcriptome, and lipids in isolated mitochondria of liver and skeletal muscle as well as in whole tissue and examined the functional consequences by high-resolution respirometry. Results HED increased the respiratory capacity of isolated liver mitochondria, both in sedentary and in trained mice. However, proteomics analysis of the mitochondria and transcriptomics indicated that training modified the adaptation of the hepatic metabolism to HED on the level of respiratory complex I, glucose oxidation, pyruvate and acetyl-CoA metabolism, and lipogenesis. Training also counteracted the HED-induced glucose intolerance, the increase in fasting insulin, and in liver fat by lowering diacylglycerol species and c-Jun N-terminal kinase (JNK) phosphorylation in the livers of trained HED-fed mice, two mechanisms that can reverse hepatic insulin resistance. In skeletal muscle, the combination of HED and training improved the oxidative capacity to a greater extent than training alone by increasing respiration of isolated mitochondria and total mitochondrial protein content. Conclusion We provide a comprehensive insight into the early adaptations of mitochondria in the liver and skeletal muscle to HED and endurance training. Our results suggest that exercise disconnects the HED-induced increase in mitochondrial substrate oxidation from pyruvate and acetyl-CoA-driven lipid synthesis. This could contribute to the prevention of deleterious long-term effects of high fat and sugar intake on hepatic mitochondrial function and insulin sensitivity. High-energy diet promotes mitochondrial respiration in liver independent of training. High-energy diet combined with training disconnects substrate oxidation from lipid synthesis. High-energy diet combined with training reduces complex I formation in the liver. Trained skeletal muscle unburdens the liver from substrate overload. Comprehensive resource of mitochondrial adaptations to high-energy diet and training.
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Affiliation(s)
- Miriam Hoene
- Institute for Clinical Chemistry and Pathobiochemistry, Department for Diagnostic Laboratory Medicine, University Hospital Tuebingen, Tuebingen, Germany
| | - Lisa Kappler
- Institute for Clinical Chemistry and Pathobiochemistry, Department for Diagnostic Laboratory Medicine, University Hospital Tuebingen, Tuebingen, Germany
| | - Laxmikanth Kollipara
- Leibniz-Institut für Analytische Wissenschaften - ISAS - e.V., Dortmund, Germany
| | - Chunxiu Hu
- CAS Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, China
| | - Martin Irmler
- Helmholtz Center Munich, German Research Center for Environmental Health (GmbH), 85764, Neuherberg, Germany
| | - Daniel Bleher
- Institute for Clinical Chemistry and Pathobiochemistry, Department for Diagnostic Laboratory Medicine, University Hospital Tuebingen, Tuebingen, Germany
| | - Christoph Hoffmann
- Institute for Clinical Chemistry and Pathobiochemistry, Department for Diagnostic Laboratory Medicine, University Hospital Tuebingen, Tuebingen, Germany
| | - Johannes Beckers
- Helmholtz Center Munich, German Research Center for Environmental Health (GmbH), 85764, Neuherberg, Germany; Technische Universität München, Chair of Experimental Genetics, 85354, Freising, Germany; German Center for Diabetes Research (DZD), Germany
| | - Martin Hrabě de Angelis
- Helmholtz Center Munich, German Research Center for Environmental Health (GmbH), 85764, Neuherberg, Germany; Technische Universität München, Chair of Experimental Genetics, 85354, Freising, Germany; German Center for Diabetes Research (DZD), Germany
| | - Hans-Ulrich Häring
- German Center for Diabetes Research (DZD), Germany; Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the University of Tuebingen, Tuebingen, Germany
| | - Andreas L Birkenfeld
- German Center for Diabetes Research (DZD), Germany; Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the University of Tuebingen, Tuebingen, Germany; Department of Internal Medicine IV, University Hospital Tuebingen, Tuebingen, Germany
| | - Andreas Peter
- Institute for Clinical Chemistry and Pathobiochemistry, Department for Diagnostic Laboratory Medicine, University Hospital Tuebingen, Tuebingen, Germany; German Center for Diabetes Research (DZD), Germany; Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the University of Tuebingen, Tuebingen, Germany
| | - Albert Sickmann
- Leibniz-Institut für Analytische Wissenschaften - ISAS - e.V., Dortmund, Germany; Medizinische Fakultät, Medizinische Proteom-Center (MPC), Ruhr-Universität Bochum, Bochum, Germany; Department of Chemistry, College of Physical Sciences, University of Aberdeen, Aberdeen, Scotland, United Kingdom
| | - Guowang Xu
- CAS Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, China
| | - Rainer Lehmann
- Institute for Clinical Chemistry and Pathobiochemistry, Department for Diagnostic Laboratory Medicine, University Hospital Tuebingen, Tuebingen, Germany; German Center for Diabetes Research (DZD), Germany; Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the University of Tuebingen, Tuebingen, Germany
| | - Cora Weigert
- Institute for Clinical Chemistry and Pathobiochemistry, Department for Diagnostic Laboratory Medicine, University Hospital Tuebingen, Tuebingen, Germany; German Center for Diabetes Research (DZD), Germany; Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the University of Tuebingen, Tuebingen, Germany.
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60
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β-RA Targets Mitochondrial Metabolism and Adipogenesis, Leading to Therapeutic Benefits against CoQ Deficiency and Age-Related Overweight. Biomedicines 2021; 9:biomedicines9101457. [PMID: 34680574 PMCID: PMC8533582 DOI: 10.3390/biomedicines9101457] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Revised: 10/01/2021] [Accepted: 10/09/2021] [Indexed: 11/17/2022] Open
Abstract
Primary mitochondrial diseases are caused by mutations in mitochondrial or nuclear genes, leading to the abnormal function of specific mitochondrial pathways. Mitochondrial dysfunction is also a secondary event in more common pathophysiological conditions, such as obesity and metabolic syndrome. In both cases, the improvement and management of mitochondrial homeostasis remain challenging. Here, we show that beta-resorcylic acid (β-RA), which is a natural phenolic compound, competed in vivo with 4-hydroxybenzoic acid, which is the natural precursor of coenzyme Q biosynthesis. This led to a decrease in demethoxyubiquinone, which is an intermediate metabolite of CoQ biosynthesis that is abnormally accumulated in Coq9R239X mice. As a consequence, β-RA rescued the phenotype of Coq9R239X mice, which is a model of primary mitochondrial encephalopathy. Moreover, we observed that long-term treatment with β-RA also reduced the size and content of the white adipose tissue (WAT) that is normally accumulated during aging in wild-type mice, leading to the prevention of hepatic steatosis and an increase in survival at the elderly stage of life. The reduction in WAT content was due to a decrease in adipogenesis, an adaptation of the mitochondrial proteome in the kidneys, and stimulation of glycolysis and acetyl-CoA metabolism. Therefore, our results demonstrate that β-RA acted through different cellular mechanisms, with effects on mitochondrial metabolism; as such, it may be used for the treatment of primary coenzyme Q deficiency, overweight, and hepatic steatosis.
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Abstract
Ketone bodies play significant roles in organismal energy homeostasis, serving as oxidative fuels, modulators of redox potential, lipogenic precursors, and signals, primarily during states of low carbohydrate availability. Efforts to enhance wellness and ameliorate disease via nutritional, chronobiological, and pharmacological interventions have markedly intensified interest in ketone body metabolism. The two ketone body redox partners, acetoacetate and D-β-hydroxybutyrate, serve distinct metabolic and signaling roles in biological systems. We discuss the pleiotropic roles played by both of these ketones in health and disease. While enthusiasm is warranted, prudent procession through therapeutic applications of ketogenic and ketone therapies is also advised, as a range of metabolic and signaling consequences continue to emerge. Organ-specific and cell-type-specific effects of ketone bodies are important to consider as prospective therapeutic and wellness applications increase.
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Affiliation(s)
- Patrycja Puchalska
- Department of Medicine, Division of Molecular Medicine, University of Minnesota, Minneapolis, Minnesota 55455, USA; ,
| | - Peter A Crawford
- Department of Medicine, Division of Molecular Medicine, University of Minnesota, Minneapolis, Minnesota 55455, USA; , .,Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, Minnesota 55455, USA
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62
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Semmler G, Datz C, Reiberger T, Trauner M. Diet and exercise in NAFLD/NASH: Beyond the obvious. Liver Int 2021; 41:2249-2268. [PMID: 34328248 PMCID: PMC9292198 DOI: 10.1111/liv.15024] [Citation(s) in RCA: 66] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Revised: 07/06/2021] [Accepted: 07/10/2021] [Indexed: 12/12/2022]
Abstract
Lifestyle represents the most relevant factor for non-alcoholic fatty liver disease (NAFLD) as the hepatic manifestation of the metabolic syndrome. Although a tremendous body of clinical and preclinical data on the effectiveness of dietary and lifestyle interventions exist, the complexity of this topic makes firm and evidence-based clinical recommendations for nutrition and exercise in NAFLD difficult. The aim of this review is to guide readers through the labyrinth of recent scientific findings on diet and exercise in NAFLD and non-alcoholic steatohepatitis (NASH), summarizing "obvious" findings in a holistic manner and simultaneously highlighting stimulating aspects of clinical and translational research "beyond the obvious". Specifically, the importance of calorie restriction regardless of dietary composition and evidence from low-carbohydrate diets to target the incidence and severity of NAFLD are discussed. The aspect of ketogenesis-potentially achieved via intermittent calorie restriction-seems to be a central aspect of these diets warranting further investigation. Interactions of diet and exercise with the gut microbiota and the individual genetic background need to be comprehensively understood in order to develop personalized dietary concepts and exercise strategies for patients with NAFLD/NASH.
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Affiliation(s)
- Georg Semmler
- Division of Gastroenterology and HepatologyDepartment of Internal Medicine IIIMedical University of ViennaViennaAustria
| | - Christian Datz
- Department of Internal MedicineGeneral Hospital OberndorfTeaching Hospital of the Paracelsus Medical University SalzburgSalzburgAustria
| | - Thomas Reiberger
- Division of Gastroenterology and HepatologyDepartment of Internal Medicine IIIMedical University of ViennaViennaAustria
| | - Michael Trauner
- Division of Gastroenterology and HepatologyDepartment of Internal Medicine IIIMedical University of ViennaViennaAustria
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63
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Lu Q, Tian X, Wu H, Huang J, Li M, Mei Z, Zhou L, Xie H, Zheng S. Metabolic Changes of Hepatocytes in NAFLD. Front Physiol 2021; 12:710420. [PMID: 34526911 PMCID: PMC8437340 DOI: 10.3389/fphys.2021.710420] [Citation(s) in RCA: 48] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2021] [Accepted: 08/04/2021] [Indexed: 12/17/2022] Open
Abstract
Nonalcoholic fatty liver disease (NAFLD) is often accompanied by systemic metabolic disorders such as hyperglycemia, insulin resistance, and obesity. The relationship between NAFLD and systemic metabolic disorders has been well reviewed before, however, the metabolic changes that occur in hepatocyte itself have not been discussed. In NAFLD, many metabolic pathways have undergone significant changes in hepatocyte, such as enhanced glycolysis, gluconeogenesis, lactate production, tricarboxylic acid (TCA) cycle, and decreased ketone body production, mitochondrial respiration, and adenosine triphosphate (ATP) synthesis, which play a role in compensating or exacerbating disease progression, and there is close and complex interaction existed between these metabolic pathways. Among them, some metabolic pathways can be the potential therapeutic targets for NAFLD. A detailed summary of the metabolic characteristics of hepatocytes in the context of NAFLD helps us better understand the pathogenesis and outcomes of the disease.
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Affiliation(s)
- Qianrang Lu
- Division of Hepatobiliary and Pancreatic Surgery, Department of Surgery, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.,NHC Key Laboratory of Combined Multi-organ Transplantation, Hangzhou, China
| | - Xinyao Tian
- Division of Hepatobiliary and Pancreatic Surgery, Department of Surgery, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.,NHC Key Laboratory of Combined Multi-organ Transplantation, Hangzhou, China
| | - Hao Wu
- Division of Hepatobiliary and Pancreatic Surgery, Department of Surgery, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.,NHC Key Laboratory of Combined Multi-organ Transplantation, Hangzhou, China
| | - Jiacheng Huang
- Division of Hepatobiliary and Pancreatic Surgery, Department of Surgery, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.,NHC Key Laboratory of Combined Multi-organ Transplantation, Hangzhou, China
| | - Mengxia Li
- Division of Hepatobiliary and Pancreatic Surgery, Department of Surgery, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.,NHC Key Laboratory of Combined Multi-organ Transplantation, Hangzhou, China
| | - Zhibin Mei
- Division of Hepatobiliary and Pancreatic Surgery, Department of Surgery, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.,NHC Key Laboratory of Combined Multi-organ Transplantation, Hangzhou, China
| | - Lin Zhou
- Division of Hepatobiliary and Pancreatic Surgery, Department of Surgery, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.,NHC Key Laboratory of Combined Multi-organ Transplantation, Hangzhou, China
| | - Haiyang Xie
- Division of Hepatobiliary and Pancreatic Surgery, Department of Surgery, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.,NHC Key Laboratory of Combined Multi-organ Transplantation, Hangzhou, China
| | - Shusen Zheng
- Division of Hepatobiliary and Pancreatic Surgery, Department of Surgery, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.,NHC Key Laboratory of Combined Multi-organ Transplantation, Hangzhou, China.,Department of Hepatobiliary and Pancreatic Surgery & Liver Transplantation, Shulan (Hangzhou) Hospital, Hangzhou, China
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64
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Tsilingiris D, Tzeravini E, Koliaki C, Dalamaga M, Kokkinos A. The Role of Mitochondrial Adaptation and Metabolic Flexibility in the Pathophysiology of Obesity and Insulin Resistance: an Updated Overview. Curr Obes Rep 2021; 10:191-213. [PMID: 33840072 DOI: 10.1007/s13679-021-00434-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 03/30/2021] [Indexed: 12/27/2022]
Abstract
PURPOSE OF REVIEW The term "metabolic flexibility" denotes the dynamic responses of the cellular oxidative machinery in order to adapt to changes in energy substrate availability. A progressive loss of this adaptive capacity has been implicated in the development of obesity-related comorbidities. Mitochondria are dynamic intracellular organelles which play a fundamental role in energy metabolism, and the mitochondrial adaptation to environmental challenges may be viewed as the functional component of metabolic flexibility. Herein, we attempt to comprehensively review the available evidence regarding the role of mitochondrial adaptation and metabolic flexibility in the pathogenesis of obesity and related morbidities, namely insulin resistance states and non-alcoholic fatty liver disease (NAFLD). RECENT FINDINGS Overall, there is a concrete body of evidence to support the presence of impaired mitochondrial adaptation as a principal component of systemic metabolic inflexibility in conditions related to obesity. There are still many unresolved questions regarding the relationship between the gradual loss of mitochondrial adaptability and the progression of obesity-related complications, such as causality issues, the timely appearance and reversibility of the described disturbances, and the generalizability of the findings to the mitochondrial content of every affected tissue or organ. The evidence regarding the causality between the observed associations remains inconclusive, although most of the available data points towards a bidirectional, potentially mutually amplifying relationship. The spectrum of NAFLD is of particular interest, since functional and pathological changes in the course of its development closely mirror the progression of dysmetabolism, if not constituting a dynamic component of the latter.
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Affiliation(s)
- Dimitrios Tsilingiris
- First Department of Propaedeutic Internal Medicine, School of Medicine, Laiko General Hospital, National and Kapodistrian University of Athens, Athens, Greece.
- Department of Internal Medicine I and Clinical Chemistry, University of Heidelberg, Heidelberg, Germany.
| | - Evangelia Tzeravini
- First Department of Propaedeutic Internal Medicine, School of Medicine, Laiko General Hospital, National and Kapodistrian University of Athens, Athens, Greece
| | - Chrysi Koliaki
- First Department of Propaedeutic Internal Medicine, School of Medicine, Laiko General Hospital, National and Kapodistrian University of Athens, Athens, Greece
| | - Maria Dalamaga
- Department of Biological Chemistry, School of Medicine, National and Kapodistrian University of Athens, Mikras Asias 75, 11527, Athens, Greece
| | - Alexander Kokkinos
- First Department of Propaedeutic Internal Medicine, School of Medicine, Laiko General Hospital, National and Kapodistrian University of Athens, Athens, Greece
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65
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Bence KK, Birnbaum MJ. Metabolic drivers of non-alcoholic fatty liver disease. Mol Metab 2021; 50:101143. [PMID: 33346069 PMCID: PMC8324696 DOI: 10.1016/j.molmet.2020.101143] [Citation(s) in RCA: 101] [Impact Index Per Article: 33.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Revised: 12/02/2020] [Accepted: 12/11/2020] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND The incidence of non-alcoholic fatty liver disease (NAFLD) is rapidly increasing worldwide parallel to the global obesity epidemic. NAFLD encompasses a range of liver pathologies and most often originates from metabolically driven accumulation of fat in the liver, or non-alcoholic fatty liver (NAFL). In a subset of NAFL patients, the disease can progress to non-alcoholic steatohepatitis (NASH), which is a more severe form of liver disease characterized by hepatocyte injury, inflammation, and fibrosis. Significant progress has been made over the past decade in our understanding of NASH pathogenesis, but gaps remain in our mechanistic knowledge of the precise metabolic triggers for disease worsening. SCOPE OF REVIEW The transition from NAFL to NASH likely involves a complex constellation of multiple factors intrinsic and extrinsic to the liver. This review focuses on early metabolic events in the establishment of NAFL and initial stages of NASH. We discuss the association of NAFL with obesity as well as the role of adipose tissue in disease progression and highlight early metabolic drivers implicated in the pathological transition from hepatic fat accumulation to steatohepatitis. MAJOR CONCLUSIONS The close association of NAFL with features of metabolic syndrome highlight plausible mechanistic roles for adipose tissue health and the release of lipotoxic lipids, hepatic de novo lipogenesis (DNL), and disruption of the intestinal barrier in not only the initial establishment of hepatic steatosis, but also in mediating disease progression. Human genetic variants linked to NASH risk to date are heavily biased toward genes involved in the regulation of lipid metabolism, providing compelling support for the hypothesis that NASH is fundamentally a metabolic disease.
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Affiliation(s)
- Kendra K Bence
- Internal Medicine Research Unit, Pfizer Worldwide Research, Development, and Medical, Cambridge, MA, USA.
| | - Morris J Birnbaum
- Internal Medicine Research Unit, Pfizer Worldwide Research, Development, and Medical, Cambridge, MA, USA
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66
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Di Ciaula A, Calamita G, Shanmugam H, Khalil M, Bonfrate L, Wang DQH, Baffy G, Portincasa P. Mitochondria Matter: Systemic Aspects of Nonalcoholic Fatty Liver Disease (NAFLD) and Diagnostic Assessment of Liver Function by Stable Isotope Dynamic Breath Tests. Int J Mol Sci 2021; 22:7702. [PMID: 34299321 PMCID: PMC8305940 DOI: 10.3390/ijms22147702] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Revised: 07/08/2021] [Accepted: 07/14/2021] [Indexed: 02/07/2023] Open
Abstract
The liver plays a key role in systemic metabolic processes, which include detoxification, synthesis, storage, and export of carbohydrates, lipids, and proteins. The raising trends of obesity and metabolic disorders worldwide is often associated with the nonalcoholic fatty liver disease (NAFLD), which has become the most frequent type of chronic liver disorder with risk of progression to cirrhosis and hepatocellular carcinoma. Liver mitochondria play a key role in degrading the pathways of carbohydrates, proteins, lipids, and xenobiotics, and to provide energy for the body cells. The morphological and functional integrity of mitochondria guarantee the proper functioning of β-oxidation of free fatty acids and of the tricarboxylic acid cycle. Evaluation of the liver in clinical medicine needs to be accurate in NAFLD patients and includes history, physical exam, imaging, and laboratory assays. Evaluation of mitochondrial function in chronic liver disease and NAFLD is now possible by novel diagnostic tools. "Dynamic" liver function tests include the breath test (BT) based on the use of substrates marked with the non-radioactive, naturally occurring stable isotope 13C. Hepatocellular metabolization of the substrate will generate 13CO2, which is excreted in breath and measured by mass spectrometry or infrared spectroscopy. Breath levels of 13CO2 are biomarkers of specific metabolic processes occurring in the hepatocyte cytosol, microsomes, and mitochondria. 13C-BTs explore distinct chronic liver diseases including simple liver steatosis, non-alcoholic steatohepatitis, liver fibrosis, cirrhosis, hepatocellular carcinoma, drug, and alcohol effects. In NAFLD, 13C-BT use substrates such as α-ketoisocaproic acid, methionine, and octanoic acid to assess mitochondrial oxidation capacity which can be impaired at an early stage of disease. 13C-BTs represent an indirect, cost-effective, and easy method to evaluate dynamic liver function. Further applications are expected in clinical medicine. In this review, we discuss the involvement of liver mitochondria in the progression of NAFLD, together with the role of 13C-BT in assessing mitochondrial function and its potential use in the prevention and management of NAFLD.
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Affiliation(s)
- Agostino Di Ciaula
- Clinica Medica “A. Murri”, Department of Biomedical Sciences & Human Oncology, University of Bari Medical School, 70124 Bari, Italy; (A.D.C.); (H.S.); (M.K.); (L.B.)
| | - Giuseppe Calamita
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari “Aldo Moro”, 70100 Bari, Italy;
| | - Harshitha Shanmugam
- Clinica Medica “A. Murri”, Department of Biomedical Sciences & Human Oncology, University of Bari Medical School, 70124 Bari, Italy; (A.D.C.); (H.S.); (M.K.); (L.B.)
| | - Mohamad Khalil
- Clinica Medica “A. Murri”, Department of Biomedical Sciences & Human Oncology, University of Bari Medical School, 70124 Bari, Italy; (A.D.C.); (H.S.); (M.K.); (L.B.)
| | - Leonilde Bonfrate
- Clinica Medica “A. Murri”, Department of Biomedical Sciences & Human Oncology, University of Bari Medical School, 70124 Bari, Italy; (A.D.C.); (H.S.); (M.K.); (L.B.)
| | - David Q.-H. Wang
- Marion Bessin Liver Research Center, Einstein-Mount Sinai Diabetes Research Center, Department of Medicine and Genetics, Division of Gastroenterology and Liver Diseases, Albert Einstein College of Medicine, Bronx, NY 10461, USA;
| | - Gyorgy Baffy
- Department of Medicine, VA Boston Healthcare System and Brigham and Women’s Hospital, Harvard Medical School, Boston, MA 02130, USA;
| | - Piero Portincasa
- Clinica Medica “A. Murri”, Department of Biomedical Sciences & Human Oncology, University of Bari Medical School, 70124 Bari, Italy; (A.D.C.); (H.S.); (M.K.); (L.B.)
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67
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Abstract
The reactions of the tricarboxylic acid (TCA) cycle allow the controlled combustion of fat and carbohydrate. In principle, TCA cycle intermediates are regenerated on every turn and can facilitate the oxidation of an infinite number of nutrient molecules. However, TCA cycle intermediates can be lost to cataplerotic pathways that provide precursors for biosynthesis, and they must be replaced by anaplerotic pathways that regenerate these intermediates. Together, anaplerosis and cataplerosis help regulate rates of biosynthesis by dictating precursor supply, and they play underappreciated roles in catabolism and cellular energy status. They facilitate recycling pathways and nitrogen trafficking necessary for catabolism, and they influence redox state and oxidative capacity by altering TCA cycle intermediate concentrations. These functions vary widely by tissue and play emerging roles in disease. This article reviews the roles of anaplerosis and cataplerosis in various tissues and discusses how they alter carbon transitions, and highlights their contribution to mechanisms of disease. Expected final online publication date for the Annual Review of Nutrition, Volume 41 is September 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Melissa Inigo
- Center for Human Nutrition, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA;
| | - Stanisław Deja
- Center for Human Nutrition, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA; .,Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
| | - Shawn C Burgess
- Center for Human Nutrition, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA; .,Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
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Park S, Song J, Baek IJ, Jang KY, Han CY, Jun DW, Kim PK, Raught B, Jin EJ. Loss of Acot12 contributes to NAFLD independent of lipolysis of adipose tissue. Exp Mol Med 2021; 53:1159-1169. [PMID: 34285335 PMCID: PMC8333268 DOI: 10.1038/s12276-021-00648-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2021] [Revised: 05/11/2021] [Accepted: 06/03/2021] [Indexed: 12/20/2022] Open
Abstract
In this study, we hypothesized that deregulation in the maintenance of the pool of coenzyme A (CoA) may play a crucial role in the pathogenesis of nonalcoholic fatty liver disease (NAFLD). Specific deletion of Acot12 (Acot12-/-), the major acyl-CoA thioesterase, induced the accumulation of acetyl-CoA and resulted in the stimulation of de novo lipogenesis (DNL) and cholesterol biosynthesis in the liver. KEGG pathway analysis suggested PPARα signaling as the most significantly enriched pathway in Acot12-/- livers. Surprisingly, the exposure of Acot12-/- hepatocytes to fenofibrate significantly increased the accumulation of acetyl-CoA and resulted in the stimulation of cholesterol biosynthesis and DNL. Interaction analysis, including proximity-dependent biotin identification (BioID) analysis, suggested that ACOT12 may directly interact with vacuolar protein sorting-associated protein 33A (VPS33A) and play a role in vesicle-mediated cholesterol trafficking and the process of lysosomal degradation of cholesterol in hepatocytes. In summary, in this study, we found that ACOT12 deficiency is responsible for the pathogenesis of NAFLD through the accumulation of acetyl-CoA and the stimulation of DNL and cholesterol via activation of PPARα and inhibition of cholesterol trafficking.
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Affiliation(s)
- Sujeong Park
- Department of Biological Sciences, College of Natural Sciences, Wonkwang University, Iksan, Jeonbuk, Republic of Korea
| | - Jinsoo Song
- Department of Biological Sciences, College of Natural Sciences, Wonkwang University, Iksan, Jeonbuk, Republic of Korea
| | - In-Jeoung Baek
- Asan Institute for Life Sciences, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Kyu Yun Jang
- Department of Pathology, Jeonbuk National University Medical School, Jeonju, Republic of Korea
- Research Institute of Clinical Medicine of Jeonbuk National University-Biomedical Research Institute of Jeonbuk National University Hospital and Research Institute for Endocrine Sciences, Jeonju, Republic of Korea
| | - Chang Yeob Han
- School of Pharmacy, Jeonbuk National University, Jeonju, Jeonbuk, Republic of Korea
| | - Dae Won Jun
- Department of Internal Medicine, Hanyang University College of Medicine, Seoul, Republic of Korea
| | - Peter K Kim
- Department of Biochemistry, University of Toronto, Toronto, ON, Canada
- Program of Cell Biology, Hospital for Sick Children, Toronto, ON, Canada
| | - Brian Raught
- Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada
- Princess Margaret Cancer Center, University Health Network, Toronto, ON, Canada
| | - Eun-Jung Jin
- Department of Biological Sciences, College of Natural Sciences, Wonkwang University, Iksan, Jeonbuk, Republic of Korea.
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Mitochondrial Lipid Homeostasis at the Crossroads of Liver and Heart Diseases. Int J Mol Sci 2021; 22:ijms22136949. [PMID: 34203309 PMCID: PMC8268967 DOI: 10.3390/ijms22136949] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 06/19/2021] [Accepted: 06/25/2021] [Indexed: 12/16/2022] Open
Abstract
The prevalence of NAFLD (non-alcoholic fatty liver disease) is a rapidly increasing problem, affecting a huge population around the globe. However, CVDs (cardiovascular diseases) are the most common cause of mortality in NAFLD patients. Atherogenic dyslipidemia, characterized by plasma hypertriglyceridemia, increased small dense LDL (low-density lipoprotein) particles, and decreased HDL-C (high-density lipoprotein cholesterol) levels, is often observed in NAFLD patients. In this review, we summarize recent genetic evidence, proving the diverse nature of metabolic pathways involved in NAFLD pathogenesis. Analysis of available genetic data suggests that the altered operation of fatty-acid β-oxidation in liver mitochondria is the key process, connecting NAFLD-mediated dyslipidemia and elevated CVD risk. In addition, we discuss several NAFLD-associated genes with documented anti-atherosclerotic or cardioprotective effects, and current pharmaceutical strategies focused on both NAFLD treatment and reduction of CVD risk.
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70
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Western Diet Decreases the Liver Mitochondrial Oxidative Flux of Succinate: Insight from a Murine NAFLD Model. Int J Mol Sci 2021; 22:ijms22136908. [PMID: 34199098 PMCID: PMC8268937 DOI: 10.3390/ijms22136908] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 06/20/2021] [Accepted: 06/23/2021] [Indexed: 12/12/2022] Open
Abstract
Mitochondria play an essential role in the pathogenesis of nonalcoholic fatty liver disease (NAFLD). Previously, we found that succinate-activated respiration was the most affected mitochondrial parameter in mice with mild NAFLD. In this study, we focused on the role of succinate dehydrogenase (SDH) in NAFLD pathogenesis. To induce the progression of NAFLD to nonalcoholic steatohepatitis (NASH), C57BL/6J mice were fed a Western-style diet (WD) or control diet for 30 weeks. NAFLD severity was evaluated histologically and the expression of selected proteins and genes was assessed. Mitochondrial respiration was measured by high-resolution respirometry. Liver redox status was assessed using glutathione, malondialdehyde, and mitochondrial production of reactive oxygen species (ROS). Metabolomic analysis was performed by GC/MS. WD consumption for 30 weeks led to reduced succinate-activated respiration. We also observed decreased SDH activity, decreased expression of the SDH activator sirtuin 3, decreased gene expression of SDH subunits, and increased levels of hepatic succinate, an important signaling molecule. Succinate receptor 1 (SUCNR1) gene and protein expression were reduced in the livers of WD-fed mice. We did not observe signs of oxidative damage compared to the control group. The changes observed in WD-fed mice appear to be adaptive to prevent mitochondrial respiratory chain overload and massive ROS production.
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71
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Stagg DB, Gillingham JR, Nelson AB, Lengfeld JE, d'Avignon DA, Puchalska P, Crawford PA. Diminished ketone interconversion, hepatic TCA cycle flux, and glucose production in D-β-hydroxybutyrate dehydrogenase hepatocyte-deficient mice. Mol Metab 2021; 53:101269. [PMID: 34116232 PMCID: PMC8259407 DOI: 10.1016/j.molmet.2021.101269] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 05/28/2021] [Accepted: 06/03/2021] [Indexed: 12/20/2022] Open
Abstract
Objective Throughout the last decade, interest has intensified in intermittent fasting, ketogenic diets, and exogenous ketone therapies as prospective health-promoting, therapeutic, and performance-enhancing agents. However, the regulatory roles of ketogenesis and ketone metabolism on liver homeostasis remain unclear. Therefore, we sought to develop a better understanding of the metabolic consequences of hepatic ketone body metabolism by focusing on the redox-dependent interconversion of acetoacetate (AcAc) and D-β-hydroxybutyrate (D-βOHB). Methods Using targeted and isotope tracing high-resolution liquid chromatography-mass spectrometry, dual stable isotope tracer nuclear magnetic resonance spectroscopy-based metabolic flux modeling, and complementary physiological approaches in novel cell type-specific knockout mice, we quantified the roles of hepatocyte D-β-hydroxybutyrate dehydrogenase (BDH1), a mitochondrial enzyme required for NAD+/NADH-dependent oxidation/reduction of ketone bodies. Results Exogenously administered AcAc is reduced to D-βOHB, which increases hepatic NAD+/NADH ratio and reflects hepatic BDH1 activity. Livers of hepatocyte-specific BDH1-deficient mice did not produce D-βOHB, but owing to extrahepatic BDH1, these mice nonetheless remained capable of AcAc/D-βOHB interconversion. Compared to littermate controls, hepatocyte-specific BDH1 deficient mice exhibited diminished liver tricarboxylic acid (TCA) cycle flux and impaired gluconeogenesis, but normal hepatic energy charge overall. Glycemic recovery after acute insulin challenge was impaired in knockout mice, but they were not more susceptible to starvation-induced hypoglycemia. Conclusions Ketone bodies influence liver homeostasis. While liver BDH1 is not required for whole body equilibration of AcAc and D-βOHB, loss of the ability to interconvert these ketone bodies in hepatocytes results in impaired TCA cycle flux and glucose production. Therefore, through oxidation/reduction of ketone bodies, BDH1 is a significant contributor to hepatic mitochondrial redox, liver physiology, and organism-wide ketone body homeostasis. Exogenously administered acetoacetate is reduced to D-β-hydroxybutyrate, increasing hepatic NAD+/NADH ratio. Liver BDH1 is not required for whole body equilibration of acetoacetate and D-β-hydroxybutyrate. Hepatocyte-specific loss of BDH1 reduces hepatic TCA cycle flux, and TCA-cycle sourced gluconeogenesis. Hepatocyte-specific loss of BDH1 impairs glycemic recovery without provoking starvation-induced hypoglycemia.
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Affiliation(s)
- David B Stagg
- Division of Molecular Medicine, Department of Medicine, University of Minnesota, Minneapolis, MN, USA; Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN, USA
| | - Jacob R Gillingham
- Division of Molecular Medicine, Department of Medicine, University of Minnesota, Minneapolis, MN, USA
| | - Alisa B Nelson
- Division of Molecular Medicine, Department of Medicine, University of Minnesota, Minneapolis, MN, USA; Bioinformatics and Computational Biology Program, University of Minnesota, Minneapolis, MN, USA
| | - Justin E Lengfeld
- Division of Molecular Medicine, Department of Medicine, University of Minnesota, Minneapolis, MN, USA
| | - D André d'Avignon
- Division of Molecular Medicine, Department of Medicine, University of Minnesota, Minneapolis, MN, USA
| | - Patrycja Puchalska
- Division of Molecular Medicine, Department of Medicine, University of Minnesota, Minneapolis, MN, USA
| | - Peter A Crawford
- Division of Molecular Medicine, Department of Medicine, University of Minnesota, Minneapolis, MN, USA; Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN, USA; Bioinformatics and Computational Biology Program, University of Minnesota, Minneapolis, MN, USA.
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72
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Abstract
PURPOSE OF REVIEW Nonalcoholic fatty liver disease (NAFLD) is defined as the abnormal accumulation of lipids in the liver, called hepatic steatosis, which occurs most often as a concomitant of the metabolic syndrome. Its incidence has surged significantly in recent decades concomitant with the obesity pandemic and increasing consumption of refined carbohydrates and saturated fats. This makes a review of the origins of NAFLD timely and relevant. RECENT FINDINGS This disorder, which shares histologic markers found in alcoholic fatty liver disease, was named NAFLD to distinguish it from the latter. Recently, however, the term metabolic-associated fatty liver disease (MAFLD) has been suggested as a refinement of NAFLD that should highlight the central, etiologic role of insulin resistance, obesity, and diabetes mellitus. The complexity of the pathways involved in the regulation of hepatic triglyceride synthesis and utilization have become obvious over the past 10 years, including the recent identification of monogenic causes of metabolic-associated fatty liver disease. These include PNPLA3, transmembrane 6 superfamily member 2, GCKR, membrane-bound O-acyltransferase 7 suggest targets for new therapies for hepatic steatosis. SUMMARY The current review can serve as a guide to the complex pathways involved in the maintenance of hepatic triglyceride levels as well as an introduction to the most recent discoveries, including those of key genes that have provided opportunities for new and novel therapeutics.
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Affiliation(s)
- Leinys S Santos-Baez
- Division of Preventive Medicine and Nutrition, Department of Medicine, Vagelos College of Physicians and Surgeons, Columbia University, New York, New York, USA
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73
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Bednarski TK, Rahim M, Young JD. In vivo 2H/ 13C flux analysis in metabolism research. Curr Opin Biotechnol 2021; 71:1-8. [PMID: 34048994 DOI: 10.1016/j.copbio.2021.04.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Revised: 03/29/2021] [Accepted: 04/26/2021] [Indexed: 12/12/2022]
Abstract
Identifying the factors and mechanisms that regulate metabolism under normal and diseased states requires methods to quantify metabolic fluxes of live tissues within their physiological milieu. A number of recent developments have expanded the reach and depth of isotope-based in vivo flux analysis, which have in turn challenged existing dogmas in metabolism research. First, minimally invasive techniques of intravenous isotope infusion and sampling have advanced in vivo metabolic tracer studies in animal models and human subjects. Second, recent breakthroughs in analytical instrumentation have expanded the scope of isotope labeling measurements and reduced sample volume requirements. Third, innovative modeling approaches and publicly available software tools have facilitated rigorous analysis of sophisticated experimental designs involving multiple tracers and expansive metabolomics datasets. These developments have enabled comprehensive in vivo quantification of metabolic fluxes in specific tissues and have set the stage for integrated multi-tissue flux assays.
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Affiliation(s)
- Tomasz K Bednarski
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, TN, USA
| | - Mohsin Rahim
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, TN, USA
| | - Jamey D Young
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, TN, USA; Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN, USA.
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74
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Di Ciaula A, Passarella S, Shanmugam H, Noviello M, Bonfrate L, Wang DQH, Portincasa P. Nonalcoholic Fatty Liver Disease (NAFLD). Mitochondria as Players and Targets of Therapies? Int J Mol Sci 2021; 22:ijms22105375. [PMID: 34065331 PMCID: PMC8160908 DOI: 10.3390/ijms22105375] [Citation(s) in RCA: 65] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2021] [Revised: 05/14/2021] [Accepted: 05/18/2021] [Indexed: 12/12/2022] Open
Abstract
Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease and represents the hepatic expression of several metabolic abnormalities of high epidemiologic relevance. Fat accumulation in the hepatocytes results in cellular fragility and risk of progression toward necroinflammation, i.e., nonalcoholic steatohepatitis (NASH), fibrosis, cirrhosis, and eventually hepatocellular carcinoma. Several pathways contribute to fat accumulation and damage in the liver and can also involve the mitochondria, whose functional integrity is essential to maintain liver bioenergetics. In NAFLD/NASH, both structural and functional mitochondrial abnormalities occur and can involve mitochondrial electron transport chain, decreased mitochondrial β-oxidation of free fatty acids, excessive generation of reactive oxygen species, and lipid peroxidation. NASH is a major target of therapy, but there is no established single or combined treatment so far. Notably, translational and clinical studies point to mitochondria as future therapeutic targets in NAFLD since the prevention of mitochondrial damage could improve liver bioenergetics.
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Affiliation(s)
- Agostino Di Ciaula
- Department of Biomedical Sciences & Human Oncology, Clinica Medica “A. Murri”, University of Bari Medical School, 70124 Bari, Italy; (A.D.C.); (H.S.); (M.N.); (L.B.)
| | - Salvatore Passarella
- School of Medicine, University of Bari Medical School, 70124 Bari, Italy
- Correspondence: (S.P.); (P.P.); Tel.: +39-328-468-7215 (P.P.)
| | - Harshitha Shanmugam
- Department of Biomedical Sciences & Human Oncology, Clinica Medica “A. Murri”, University of Bari Medical School, 70124 Bari, Italy; (A.D.C.); (H.S.); (M.N.); (L.B.)
| | - Marica Noviello
- Department of Biomedical Sciences & Human Oncology, Clinica Medica “A. Murri”, University of Bari Medical School, 70124 Bari, Italy; (A.D.C.); (H.S.); (M.N.); (L.B.)
| | - Leonilde Bonfrate
- Department of Biomedical Sciences & Human Oncology, Clinica Medica “A. Murri”, University of Bari Medical School, 70124 Bari, Italy; (A.D.C.); (H.S.); (M.N.); (L.B.)
| | - David Q.-H. Wang
- Department of Medicine and Genetics, Division of Gastroenterology and Liver Diseases, Marion Bessin Liver Research Center, Einstein-Mount Sinai Diabetes Research Center, Albert Einstein College of Medicine, Bronx, NY 10461, USA;
| | - Piero Portincasa
- Department of Biomedical Sciences & Human Oncology, Clinica Medica “A. Murri”, University of Bari Medical School, 70124 Bari, Italy; (A.D.C.); (H.S.); (M.N.); (L.B.)
- Correspondence: (S.P.); (P.P.); Tel.: +39-328-468-7215 (P.P.)
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In Vivo Estimation of Ketogenesis Using Metabolic Flux Analysis-Technical Aspects and Model Interpretation. Metabolites 2021; 11:metabo11050279. [PMID: 33924948 PMCID: PMC8146959 DOI: 10.3390/metabo11050279] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 04/21/2021] [Accepted: 04/23/2021] [Indexed: 01/26/2023] Open
Abstract
Ketogenesis occurs in liver mitochondria where acetyl-CoA molecules, derived from lipid oxidation, are condensed into acetoacetate (AcAc) and reduced to β-hydroxybutyrate (BHB). During carbohydrate scarcity, these two ketones are released into circulation at high rates and used as oxidative fuels in peripheral tissues. Despite their physiological relevance and emerging roles in a variety of diseases, endogenous ketone production is rarely measured in vivo using tracer approaches. Accurate determination of this flux requires a two-pool model, simultaneous BHB and AcAc tracers, and special consideration for the stability of the AcAc tracer and analyte. We describe the implementation of a two-pool model using a metabolic flux analysis (MFA) approach that simultaneously regresses liquid chromatography-tandem mass spectrometry (LC-MS/MS) ketone isotopologues and tracer infusion rates. Additionally, 1H NMR real-time reaction monitoring was used to evaluate AcAc tracer and analyte stability during infusion and sample analysis, which were critical for accurate flux calculations. The approach quantifies AcAc and BHB pool sizes and their rates of appearance, disposal, and exchange. Regression analysis provides confidence intervals and detects potential errors in experimental data. Complications for the physiological interpretation of individual ketone fluxes are discussed.
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76
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Demyanova EV, Shcherbakova ES, Sall TS, Bakulin IG, Vakhitov TY, Sitkin SI. Non-targeted Serum Metabolomics Identifies Candidate Biomarkers Panels Associated with Nonalcoholic Fatty Liver Disease: A Pilot Study in Russian Male Patients. THE OPEN BIOMARKERS JOURNAL 2021; 11:17-27. [DOI: 10.2174/1875318302111010017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 01/04/2021] [Accepted: 01/07/2021] [Indexed: 09/26/2023]
Abstract
Aims:
The aim of the present study was to explore changes in the serum metabolome of patients with NAFLD relative to healthy controls to identify biomarkers associated with steatosis or Non-Alcoholic Steatohepatitis (NASH).
Background:
The serum metabolome reflects changes at the organismal level. This is especially important in Non-Alcoholic Liver Disease (NAFLD), where changes in hormones, cytokines, enzymes and other metabolic alterations can affect the liver, as well as adipose tissue, skeletal muscle and other systems.
Objective:
The objectives were to conduct non-targeted serum metabolomics, data processing, and identification of candidate biomarkers, as well as panels and assessment of their prognostic value.
Materials and Methods:
Non-targeted metabolomic analysis of blood serum samples from 21 male patients with NAFLD (simple steatosis or NASH) and seven male Control group was performed using gas chromatography-mass spectrometry.
Results:
A total of 319 serum metabolites were detected in NAFLD and Control groups, several of which differed significantly between groups. The most discriminating biomarkers were 3-hydroxybutyric acid, 2-hydroxybutyric acid, 2,3-dihydroxybutyric acid, arabitol and 3-methyl-2-oxovaleric acid. Using a panel of three, four or more markers could distinguish patients with NAFLD from controls, and patients with NASH from those with simple steatosis.
Conclusion:
We identified candidate biomarkers for simple steatosis and NASH. Since NAFLD is a multifactorial disease, it is preferable to use a marker panel rather than individual metabolites. Markers may not only result from dysregulation of metabolic pathways in patients with NAFLD, they may also reflect adaptive responses to disease, including functional changes in the intestinal microbiota.
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77
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Qian X, Wang T, Gong J, Wang L, Chen X, Lin H, Tu W, Jiang S, Li S. Exercise in mice ameliorates high-fat diet-induced nonalcoholic fatty liver disease by lowering HMGCS2. Aging (Albany NY) 2021; 13:8960-8974. [PMID: 33647884 PMCID: PMC8034885 DOI: 10.18632/aging.202717] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Accepted: 01/14/2021] [Indexed: 12/18/2022]
Abstract
Nonalcoholic fatty liver disease (NAFLD) is a common chronic liver disease worldwide. Exercise is a therapeutic strategy for preventing NAFLD. However, the underlying molecular mechanisms by which NAFLD can be ameliorated through exercise are still not clear. This study investigates the mechanisms by which exercise suppresses NAFLD development induced by a high-fat diet (HFD) in mice. Male 6-week-old C57BL/6J mice were fed a normal diet or HFD for 12 weeks and then induced to swim or remain sedentary for 8 weeks. Histomorphology, inflammatory factors, fat metabolizing enzymes, fibrosis, and steatosis were determined in HFD-fed mouse liver, and levels of hepatic enzymes and molecules in the related pathways were analyzed. NAFLD mice showed evident steatosis, fibrosis, and liver injury, and an increased expression of HMGCS2, Wnt3a/ β-catenin, and phosphorylated (p)-AMPK in the liver. Exercise significantly attenuated these symptoms and downregulated the level of Wnt3a/β-catenin in lipotoxic liver tissue. Inhibition of HMGCS2 expression decreased the activation of the Wnt3a/β-catenin pathway and lowered p-AMPK in palmitate-treated HepG2. Our results suggest that exercise prevents NAFLD-associated liver injury, steatosis, and fibrosis. Exercise-mediated hepatoprotection was achieved partly via the blocking of the upregulation of HMGCS2 and the attenuation of the Wnt3a/β-catenin pathway.
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Affiliation(s)
- Xiaoli Qian
- Rehabilitation Medicine Center, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou 325027, Zhejiang, China.,Integrative and Optimized Medicine Research Center, China-USA Institute for Acupuncture and Rehabilitation, Wenzhou Medical University, Wenzhou 325027, Zhejiang, China
| | - Ting Wang
- Rehabilitation Medicine Center, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou 325027, Zhejiang, China.,Integrative and Optimized Medicine Research Center, China-USA Institute for Acupuncture and Rehabilitation, Wenzhou Medical University, Wenzhou 325027, Zhejiang, China
| | - Jiahong Gong
- Rehabilitation Medicine Center, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou 325027, Zhejiang, China.,Integrative and Optimized Medicine Research Center, China-USA Institute for Acupuncture and Rehabilitation, Wenzhou Medical University, Wenzhou 325027, Zhejiang, China
| | - Li Wang
- Rehabilitation Medicine Center, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou 325027, Zhejiang, China.,Integrative and Optimized Medicine Research Center, China-USA Institute for Acupuncture and Rehabilitation, Wenzhou Medical University, Wenzhou 325027, Zhejiang, China
| | - Xuyan Chen
- Rehabilitation Medicine Center, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou 325027, Zhejiang, China.,Integrative and Optimized Medicine Research Center, China-USA Institute for Acupuncture and Rehabilitation, Wenzhou Medical University, Wenzhou 325027, Zhejiang, China
| | - Haiyan Lin
- Rehabilitation Medicine Center, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou 325027, Zhejiang, China.,Integrative and Optimized Medicine Research Center, China-USA Institute for Acupuncture and Rehabilitation, Wenzhou Medical University, Wenzhou 325027, Zhejiang, China
| | - Wenzhan Tu
- Rehabilitation Medicine Center, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou 325027, Zhejiang, China.,Integrative and Optimized Medicine Research Center, China-USA Institute for Acupuncture and Rehabilitation, Wenzhou Medical University, Wenzhou 325027, Zhejiang, China
| | - Songhe Jiang
- Rehabilitation Medicine Center, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou 325027, Zhejiang, China.,Integrative and Optimized Medicine Research Center, China-USA Institute for Acupuncture and Rehabilitation, Wenzhou Medical University, Wenzhou 325027, Zhejiang, China
| | - Shengcun Li
- Rehabilitation Medicine Center, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou 325027, Zhejiang, China.,Integrative and Optimized Medicine Research Center, China-USA Institute for Acupuncture and Rehabilitation, Wenzhou Medical University, Wenzhou 325027, Zhejiang, China
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78
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Exploiting S-nitrosylation for cancer therapy: facts and perspectives. Biochem J 2021; 477:3649-3672. [PMID: 33017470 DOI: 10.1042/bcj20200064] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 09/02/2020] [Accepted: 09/07/2020] [Indexed: 12/11/2022]
Abstract
S-nitrosylation, the post-translational modification of cysteines by nitric oxide, has been implicated in several cellular processes and tissue homeostasis. As a result, alterations in the mechanisms controlling the levels of S-nitrosylated proteins have been found in pathological states. In the last few years, a role in cancer has been proposed, supported by the evidence that various oncoproteins undergo gain- or loss-of-function modifications upon S-nitrosylation. Here, we aim at providing insight into the current knowledge about the role of S-nitrosylation in different aspects of cancer biology and report the main anticancer strategies based on: (i) reducing S-nitrosylation-mediated oncogenic effects, (ii) boosting S-nitrosylation to stimulate cell death, (iii) exploiting S-nitrosylation through synthetic lethality.
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79
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The Role of Hepatic Fat Accumulation in Glucose and Insulin Homeostasis-Dysregulation by the Liver. J Clin Med 2021; 10:jcm10030390. [PMID: 33498493 PMCID: PMC7864173 DOI: 10.3390/jcm10030390] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2020] [Revised: 01/18/2021] [Accepted: 01/19/2021] [Indexed: 11/17/2022] Open
Abstract
Accumulation of hepatic triacylglycerol (TG) is associated with obesity and metabolic syndrome, which are important pathogenic factors in the development of type 2 diabetes. In this narrative review, we summarize the effects of hepatic TG accumulation on hepatic glucose and insulin metabolism and the underlying molecular regulation in order to highlight the importance of hepatic TG accumulation for whole-body glucose metabolism. We find that liver fat accumulation is closely linked to impaired insulin-mediated suppression of hepatic glucose production and reduced hepatic insulin clearance. The resulting systemic hyperinsulinemia has a major impact on whole-body glucose metabolism and may be an important pathogenic step in the development of type 2 diabetes.
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80
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Kalra S, Unnikrishnan AG, Baruah MP, Sahay R, Bantwal G. Metabolic and Energy Imbalance in Dysglycemia-Based Chronic Disease. Diabetes Metab Syndr Obes 2021; 14:165-184. [PMID: 33488105 PMCID: PMC7816219 DOI: 10.2147/dmso.s286888] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Accepted: 12/02/2020] [Indexed: 12/16/2022] Open
Abstract
Metabolic flexibility is the ability to efficiently adapt metabolism based on nutrient availability and requirement that is essential to maintain homeostasis in times of either caloric excess or restriction and during the energy-demanding state. This regulation is orchestrated in multiple organ systems by the alliance of numerous metabolic pathways under the master control of the insulin-glucagon-sympathetic neuro-endocrine axis. This, in turn, regulates key metabolic enzymes and transcription factors, many of which interact closely with and culminate in the mitochondrial energy generation machinery. Metabolic flexibility is compromised due to the continuous mismatch between availability and intake of calorie-dense foods and reduced metabolic demand due to sedentary lifestyle and age-related metabolic slowdown. The resultant nutrient overload leads to mitochondrial trafficking of substrates manifesting as mitochondrial dysfunction characterized by ineffective substrate switching and incomplete substrate utilization. At the systemic level, the manifestation of metabolic inflexibility comprises reduced skeletal muscle glucose disposal rate, impaired suppression of hepatic gluconeogenesis and adipose tissue lipolysis manifesting as insulin resistance. This is compounded by impaired β-cell function and progressively reduced β-cell mass. A consequence of insulin resistance is the upregulation of the mitogen-activated protein kinase pathway leading to a pro-hypertensive, atherogenic, and thrombogenic environment. This is further aggravated by oxidative stress, advanced glycation end products, and inflammation, which potentiates the risk of micro- and macro-vascular complications. This review aims to elucidate underlying mechanisms mediating the onset of metabolic inflexibility operating at the main target organs and to understand the progression of metabolic diseases. This could potentially translate into a pharmacological tool that can manage multiple interlinked conditions of dysglycemia, hypertension, and dyslipidemia by restoring metabolic flexibility. We discuss the breadth and depth of metabolic flexibility and its impact on health and disease.
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Affiliation(s)
- Sanjay Kalra
- Department of Endocrinology, Bharti Hospital, Karnal, India
- Department of Endocrinology, All India Institute of Medical Sciences, Rishikesh, Uttarakhand, India
| | | | - Manash P Baruah
- Department of Endocrinology, Excel Hospitals, Guwahati, India
| | - Rakesh Sahay
- Department of Endocrinology, Osmania Medical College, Hyderabad, Telangana, India
| | - Ganapathi Bantwal
- Department of Endocrinology, St. John’s Medical College and Hospital, Bangalore, Karnataka, India
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81
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Exploring Liver Mitochondrial Function by 13C-Stable Isotope Breath Tests: Implications in Clinical Biochemistry. Methods Mol Biol 2021; 2310:179-199. [PMID: 34096004 DOI: 10.1007/978-1-0716-1433-4_11] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The liver is at the crossroad of key metabolic processes, which include detoxification, glycolipidic storage and export, and protein synthesis. The gut-liver axis, moreover, provides hepatocytes with a series of bacterial products and metabolites, which contribute to maintain liver function in health and disease. Breath tests (BTs) are developed as diagnostic tools for indirect, rapid, noninvasive assessment of several metabolic processes in the liver. BTs monitor the appearance of CO2 in breath as a marker of a specific substrate metabolized in the liver, typically within microsomes, cytosol, or mitochondria. The noninvasiveness of BTs originates from the use of the, nonradioactive, naturally occurring stable isotope 13C marking a specific substrate which is metabolized in the liver, leading to the appearance of 13CO2 in expired air. Some substrates (ketoisocaproic acid, methionine, and octanoic acid) provide information about dynamic liver mitochondrial function in health and disease. In humans, the application of 13C-breath tests ranges from nonalcoholic and alcoholic liver diseases to liver cirrhosis, hepatocarcinoma, preoperative and postoperative assessment of liver function, and drug-induced liver damage. 13C-BTs are an indirect, cost-effective, and easy method to evaluate dynamic liver function and gastric kinetics in health and disease, with ongoing studies focusing on further applications in clinical medicine.
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82
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Grattagliano I, Di Ciaula A, Baj J, Molina-Molina E, Shanmugam H, Garruti G, Wang DQH, Portincasa P. Protocols for Mitochondria as the Target of Pharmacological Therapy in the Context of Nonalcoholic Fatty Liver Disease (NAFLD). Methods Mol Biol 2021; 2310:201-246. [PMID: 34096005 PMCID: PMC8580566 DOI: 10.1007/978-1-0716-1433-4_12] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Nonalcoholic fatty liver disease (NAFLD) is one of the most frequent metabolic chronic liver diseases in developed countries and puts the populations at risk of progression to liver necro-inflammation, fibrosis, cirrhosis, and hepatocellular carcinoma. Mitochondrial dysfunction is involved in the onset of NAFLD and contributes to the progression from NAFLD to nonalcoholic steatohepatitis (NASH). Thus, liver mitochondria could become the target for treatments for improving liver function in NAFLD patients. This chapter describes the most important steps used for potential therapeutic interventions in NAFLD patients, discusses current options gathered from both experimental and clinical evidence, and presents some novel options for potentially improving mitochondrial function in NAFLD.
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Affiliation(s)
- Ignazio Grattagliano
- Clinica Medica "A. Murri", Department of Biomedical Sciences and Human Oncology, University of Bari Medical School, Bari, Italy
- Italian College of General Practitioners and Primary Care, Bari, Italy
| | - Agostino Di Ciaula
- Clinica Medica "A. Murri", Department of Biomedical Sciences and Human Oncology, University of Bari Medical School, Bari, Italy
| | - Jacek Baj
- Department of Anatomy, Medical University of Lublin, Lublin, Poland
| | - Emilio Molina-Molina
- Clinica Medica "A. Murri", Department of Biomedical Sciences and Human Oncology, University of Bari Medical School, Bari, Italy
| | - Harshitha Shanmugam
- Clinica Medica "A. Murri", Department of Biomedical Sciences and Human Oncology, University of Bari Medical School, Bari, Italy
| | - Gabriella Garruti
- Section of Endocrinology, Department of Emergency and Organ Transplantations, University of Bari "Aldo Moro" Medical School, Bari, Italy
| | - David Q-H Wang
- Division of Gastroenterology and Liver Diseases, Department of Medicine and Genetics, Marion Bessin Liver Research Center, Einstein-Mount Sinai Diabetes Research Center, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Piero Portincasa
- Clinica Medica "A. Murri", Department of Biomedical Sciences and Human Oncology, University of Bari Medical School, Bari, Italy.
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83
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Fernandes GW, Bocco BMLC. Hepatic Mediators of Lipid Metabolism and Ketogenesis: Focus on Fatty Liver and Diabetes. Curr Diabetes Rev 2021; 17:e110320187539. [PMID: 33143628 DOI: 10.2174/1573399816999201103141216] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2020] [Revised: 09/29/2020] [Accepted: 10/03/2020] [Indexed: 11/22/2022]
Abstract
BACKGROUND Diabetes mellitus (DM) is a chronic disorder that it is caused by the absence of insulin secretion due to the inability of the pancreas to produce it (type 1 diabetes; T1DM), or due to defects of insulin signaling in the peripheral tissues, resulting in insulin resistance (type 2 diabetes; T2DM). Commonly, the occurrence of insulin resistance in T2DM patients reflects the high prevalence of obesity and non-alcoholic fatty liver disease (NAFLD) in these individuals. In fact, approximately 60% of T2DM patients are also diagnosed to have NAFLD, and this condition is strongly linked with insulin resistance and obesity. NAFLD is the hepatic manifestation of obesity and metabolic syndrome and includes a spectrum of pathological conditions, which range from simple steatosis (NAFL), non-alcoholic steatohepatitis (NASH), cirrhosis and hepatocellular carcinoma. NAFLD manifestation is followed by a series of hepatic lipid deregulations and the main abnormalities are increased triglyceride levels, increased hepatic production of VLDL and a reduction in VLDL catabolism. During the progression of NAFLD, the production of ketone bodies progressively reduces while hepatic glucose synthesis and output increases. In fact, most of the fat that enters the liver can be disposed of through ketogenesis, preventing the development of NAFLD and hyperglycemia. OBJECTIVE This review will focus on the pathophysiological aspect of hepatic lipid metabolism deregulation, ketogenesis, and its relevance in the progression of NAFLD and T2DM. CONCLUSION A better understanding of the molecular mediators involved in lipid synthesis and ketogenesis can lead to new treatments for metabolic disorders in the liver, such as NAFLD.
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Affiliation(s)
- Gustavo W Fernandes
- Department of Medicine, Section of Endocrinology, Diabetes and Metabolism, University of Chicago, Chicago IL, United States
| | - Barbara M L C Bocco
- Department of Medicine, Section of Endocrinology, Diabetes and Metabolism, University of Chicago, Chicago IL, United States
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84
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Abstract
Background Mitochondrial oxidative function plays a key role in the development of non-alcoholic fatty liver disease (NAFLD) and insulin resistance (IR). Recent studies reported that fatty liver might not be a result of decreased mitochondrial fat oxidation caused by mitochondrial damage. Rather, NAFLD and IR induce an elevation in mitochondrial function that covers the increased demand for carbon intermediates and ATP caused by elevated lipogenesis and gluconeogenesis. Furthermore, mitochondria play a role in regulating hepatic insulin sensitivity and lipogenesis by modulating redox-sensitive signaling pathways. Scope of review We review the contradictory studies indicating that NAFLD and hyperglycemia can either increase or decrease mitochondrial oxidative capacity in the liver. We summarize mechanisms regulating mitochondrial heterogeneity inside the same cell and discuss how these mechanisms may determine the role of mitochondria in NAFLD. We further discuss the role of endogenous antioxidants in controlling mitochondrial H2O2 release and redox-mediated signaling. We describe the emerging concept that the subcellular location of cellular antioxidants is a key determinant of their effects on NAFLD. Major conclusions The balance of fat oxidation versus accumulation depends on mitochondrial fuel preference rather than ATP-synthesizing respiration. As such, therapies targeting fuel preference might be more suitable for treating NAFLD. Similarly, suppressing maladaptive antioxidants, rather than interfering with physiological mitochondrial H2O2-mediated signaling, may allow the maintenance of intact hepatic insulin signaling in NAFLD. Exploration of the subcellular compartmentalization of different antioxidant systems and the unique functions of specific mitochondrial subpopulations may offer new intervention points to treat NAFLD. Mitochondrial function has been reported to be increased or decreased in NAFLD. Functionally independent subpopulations of mitochondria can clarify the conundrum of these conflicting reports. Maladaptive antioxidants decreasing mitochondrial H2O2 and promoting NAFLD are discussed. Therapies targeting mitochondria to treat NAFLD are discussed.
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85
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Shah AM, Wondisford FE. Tracking the carbons supplying gluconeogenesis. J Biol Chem 2020; 295:14419-14429. [PMID: 32817317 PMCID: PMC7573258 DOI: 10.1074/jbc.rev120.012758] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Revised: 08/12/2020] [Indexed: 11/06/2022] Open
Abstract
As the burden of type 2 diabetes mellitus (T2DM) grows in the 21st century, the need to understand glucose metabolism heightens. Increased gluconeogenesis is a major contributor to the hyperglycemia seen in T2DM. Isotope tracer experiments in humans and animals over several decades have offered insights into gluconeogenesis under euglycemic and diabetic conditions. This review focuses on the current understanding of carbon flux in gluconeogenesis, including substrate contribution of various gluconeogenic precursors to glucose production. Alterations of gluconeogenic metabolites and fluxes in T2DM are discussed. We also highlight ongoing knowledge gaps in the literature that require further investigation. A comprehensive analysis of gluconeogenesis may enable a better understanding of T2DM pathophysiology and identification of novel targets for treating hyperglycemia.
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Affiliation(s)
- Ankit M Shah
- Department of Medicine, Robert Wood Johnson Medical School, Rutgers University, New Brunswick, New Jersey, USA
| | - Fredric E Wondisford
- Department of Medicine, Robert Wood Johnson Medical School, Rutgers University, New Brunswick, New Jersey, USA
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86
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Mandala A, Janssen RC, Palle S, Short KR, Friedman JE. Pediatric Non-Alcoholic Fatty Liver Disease: Nutritional Origins and Potential Molecular Mechanisms. Nutrients 2020; 12:E3166. [PMID: 33081177 PMCID: PMC7602751 DOI: 10.3390/nu12103166] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Revised: 10/12/2020] [Accepted: 10/13/2020] [Indexed: 02/06/2023] Open
Abstract
Non-alcoholic fatty liver disease (NAFLD) is the number one chronic liver disease worldwide and is estimated to affect nearly 40% of obese youth and up to 10% of the general pediatric population without any obvious signs or symptoms. Although the early stages of NAFLD are reversible with diet and lifestyle modifications, detecting such stages is hindered by a lack of non-invasive methods of risk assessment and diagnosis. This absence of non-invasive means of diagnosis is directly related to the scarcity of long-term prospective studies of pediatric NAFLD in children and adolescents. In the majority of pediatric NAFLD cases, the mechanisms driving the origin and rapid progression of NAFLD remain unknown. The progression from NAFLD to non-alcoholic steatohepatitis (NASH) in youth is associated with unique histological features and possible immune processes and metabolic pathways that may reflect different mechanisms compared with adults. Recent data suggest that circulating microRNAs (miRNAs) are important new biomarkers underlying pathways of liver injury. Several factors may contribute to pediatric NAFLD development, including high-sugar diets, in utero exposures via epigenetic alterations, changes in the neonatal microbiome, and altered immune system development and mitochondrial function. This review focuses on the unique aspects of pediatric NAFLD and how nutritional exposures impact the immune system, mitochondria, and liver/gastrointestinal metabolic health. These factors highlight the need for answers to how NAFLD develops in children and for early stage-specific interventions.
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Affiliation(s)
- Ashok Mandala
- Harold Hamm Diabetes Center, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; (A.M.); (R.C.J.); (K.R.S.)
| | - Rachel C. Janssen
- Harold Hamm Diabetes Center, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; (A.M.); (R.C.J.); (K.R.S.)
| | - Sirish Palle
- Department of Pediatrics, Section of Gastroenterology, Hepatology & Nutrition, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA;
| | - Kevin R. Short
- Harold Hamm Diabetes Center, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; (A.M.); (R.C.J.); (K.R.S.)
- Department of Pediatrics, Section of Diabetes and Endocrinology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Jacob E. Friedman
- Harold Hamm Diabetes Center, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; (A.M.); (R.C.J.); (K.R.S.)
- Department of Pediatrics, Section of Diabetes and Endocrinology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
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87
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Asif S, Morrow NM, Mulvihill EE, Kim KH. Understanding Dietary Intervention-Mediated Epigenetic Modifications in Metabolic Diseases. Front Genet 2020; 11:590369. [PMID: 33193730 PMCID: PMC7593700 DOI: 10.3389/fgene.2020.590369] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2020] [Accepted: 09/21/2020] [Indexed: 12/12/2022] Open
Abstract
The global prevalence of metabolic disorders, such as obesity, diabetes and fatty liver disease, is dramatically increasing. Both genetic and environmental factors are well-known contributors to the development of these diseases and therefore, the study of epigenetics can provide additional mechanistic insight. Dietary interventions, including caloric restriction, intermittent fasting or time-restricted feeding, have shown promising improvements in patients' overall metabolic profiles (i.e., reduced body weight, improved glucose homeostasis), and an increasing number of studies have associated these beneficial effects with epigenetic alterations. In this article, we review epigenetic changes involved in both metabolic diseases and dietary interventions in primary metabolic tissues (i.e., adipose, liver, and pancreas) in hopes of elucidating potential biomarkers and therapeutic targets for disease prevention and treatment.
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Affiliation(s)
- Shaza Asif
- University of Ottawa Heart Institute, Ottawa, ON, Canada
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada
| | - Nadya M. Morrow
- University of Ottawa Heart Institute, Ottawa, ON, Canada
- Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada
| | - Erin E. Mulvihill
- University of Ottawa Heart Institute, Ottawa, ON, Canada
- Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada
| | - Kyoung-Han Kim
- University of Ottawa Heart Institute, Ottawa, ON, Canada
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada
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88
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Moore MP, Cunningham RP, Dashek RJ, Mucinski JM, Rector RS. A Fad too Far? Dietary Strategies for the Prevention and Treatment of NAFLD. Obesity (Silver Spring) 2020; 28:1843-1852. [PMID: 32893456 PMCID: PMC7511422 DOI: 10.1002/oby.22964] [Citation(s) in RCA: 61] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 06/04/2020] [Accepted: 06/06/2020] [Indexed: 12/13/2022]
Abstract
Nonalcoholic fatty liver disease (NAFLD) is a major health problem, and its prevalence has increased in recent years, concurrent with rising rates of obesity and other metabolic diseases. Currently, there are no FDA-approved pharmacological therapies for NAFLD, and lifestyle interventions, including weight loss and exercise, remain the cornerstones for treatment. Manipulating diet composition and eating patterns may be a sustainable approach to NAFLD treatment. Dietary strategies including Paleolithic, ketogenic, Mediterranean, high-protein, plant-based, low-carbohydrate, and intermittent fasting diets have become increasingly popular because of their purported benefits on metabolic disease. This review highlights what is currently known about these popular dietary approaches in the management of NAFLD in clinical populations with mechanistic insight from animal studies. It also identifies key knowledge gaps to better inform future preclinical and clinical studies aimed at the treatment of NAFLD.
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Affiliation(s)
- Mary P. Moore
- Research Service, Harry S Truman Memorial Veterans Medical Center, Columbia, MO, 65211
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, MO 65211
| | - Rory P. Cunningham
- Research Service, Harry S Truman Memorial Veterans Medical Center, Columbia, MO, 65211
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, MO 65211
| | - Ryan J. Dashek
- Research Service, Harry S Truman Memorial Veterans Medical Center, Columbia, MO, 65211
- Comparative Medicine Program, University of Missouri, Columbia, MO 65211
| | - Justine M. Mucinski
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, MO 65211
| | - R. Scott Rector
- Research Service, Harry S Truman Memorial Veterans Medical Center, Columbia, MO, 65211
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, MO 65211
- Medicine-Division of Gastroenterology and Hepatology, University of Missouri, Columbia, MO 65211
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89
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Muyyarikkandy MS, McLeod M, Maguire M, Mahar R, Kattapuram N, Zhang C, Surugihalli C, Muralidaran V, Vavilikolanu K, Mathews CE, Merritt ME, Sunny NE. Branched chain amino acids and carbohydrate restriction exacerbate ketogenesis and hepatic mitochondrial oxidative dysfunction during NAFLD. FASEB J 2020; 34:14832-14849. [PMID: 32918763 DOI: 10.1096/fj.202001495r] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 08/10/2020] [Accepted: 08/24/2020] [Indexed: 12/16/2022]
Abstract
Mitochondrial adaptation during non-alcoholic fatty liver disease (NAFLD) include remodeling of ketogenic flux and sustained tricarboxylic acid (TCA) cycle activity, which are concurrent to onset of oxidative stress. Over 70% of obese humans have NAFLD and ketogenic diets are common weight loss strategies. However, the effectiveness of ketogenic diets toward alleviating NAFLD remains unclear. We hypothesized that chronic ketogenesis will worsen metabolic dysfunction and oxidative stress during NAFLD. Mice (C57BL/6) were kept (for 16-wks) on either a low-fat, high-fat, or high-fat diet supplemented with 1.5X branched chain amino acids (BCAAs) by replacing carbohydrate calories (ketogenic). The ketogenic diet induced hepatic lipid oxidation and ketogenesis, and produced multifaceted changes in flux through the individual steps of the TCA cycle. Higher rates of hepatic oxidative fluxes fueled by the ketogenic diet paralleled lower rates of de novo lipogenesis. Interestingly, this metabolic remodeling did not improve insulin resistance, but induced fibrogenic genes and inflammation in the liver. Under a chronic "ketogenic environment," the hepatocyte diverted more acetyl-CoA away from lipogenesis toward ketogenesis and TCA cycle, a milieu which can hasten oxidative stress and inflammation. In summary, chronic exposure to ketogenic environment during obesity and NAFLD has the potential to aggravate hepatic mitochondrial dysfunction.
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Affiliation(s)
| | - Marc McLeod
- Department of Biochemistry and Molecular Biology, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Meghan Maguire
- Department of Animal and Avian Sciences, University of Maryland, College Park, MD, USA
| | - Rohit Mahar
- Department of Biochemistry and Molecular Biology, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Nathan Kattapuram
- Department of Animal and Avian Sciences, University of Maryland, College Park, MD, USA
| | - Christine Zhang
- Department of Animal and Avian Sciences, University of Maryland, College Park, MD, USA
| | - Chaitra Surugihalli
- Department of Animal and Avian Sciences, University of Maryland, College Park, MD, USA
| | - Vaishna Muralidaran
- Department of Animal and Avian Sciences, University of Maryland, College Park, MD, USA
| | - Kruthi Vavilikolanu
- Department of Animal and Avian Sciences, University of Maryland, College Park, MD, USA
| | - Clayton E Mathews
- Department of Biochemistry and Molecular Biology, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Matthew E Merritt
- Department of Biochemistry and Molecular Biology, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Nishanth E Sunny
- Department of Animal and Avian Sciences, University of Maryland, College Park, MD, USA
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90
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Ferron PJ, Gicquel T, Mégarbane B, Clément B, Fromenty B. Treatments in Covid-19 patients with pre-existing metabolic dysfunction-associated fatty liver disease: A potential threat for drug-induced liver injury? Biochimie 2020; 179:266-274. [PMID: 32891697 PMCID: PMC7468536 DOI: 10.1016/j.biochi.2020.08.018] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 08/27/2020] [Accepted: 08/30/2020] [Indexed: 02/07/2023]
Abstract
Obese patients who often present metabolic dysfunction-associated fatty liver disease (MAFLD) are at risk of severe presentation of coronavirus disease 2019 (COVID-19). These patients are more likely to be hospitalized and receive antiviral agents and other drugs required to treat acute respiratory distress syndrome and systemic inflammation, combat bacterial and fungal superinfections and reverse multi-organ failure. Among these pharmaceuticals, antiretrovirals such as lopinavir/ritonavir and remdesivir, antibiotics and antifungal agents can induce drug-induced liver injury (DILI), whose mechanisms are not always understood. In the present article, we hypothesize that obese COVID-19 patients with MAFLD might be at higher risk for DILI than non-infected healthy individuals or MAFLD patients. These patients present several concomitant factors, which individually can favour DILI: polypharmacy, systemic inflammation at risk of cytokine storm, fatty liver and sometimes nonalcoholic steatohepatitis (NASH) as well as insulin resistance and other diseases linked to obesity. Hence, in obese COVID-19 patients, some drugs might cause more severe (and/or more frequent) DILI, while others might trigger the transition of fatty liver to NASH, or worsen pre-existing steatosis, necroinflammation and fibrosis. We also present the main mechanisms whereby drugs can be more hepatotoxic in MAFLD including impaired activity of xenobiotic-metabolizing enzymes, mitochondrial dysfunction, altered lipid homeostasis and oxidative stress. Although comprehensive investigations are needed to confirm our hypothesis, we believe that the current epidemic of obesity and related metabolic diseases has extensively contributed to increase the number of cases of DILI in COVID-19 patients, which may have participated in presentation severity and death.
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Affiliation(s)
- Pierre-Jean Ferron
- INSERM, Univ Rennes, INRAE, Institut NUMECAN (Nutrition Metabolisms and Cancer) UMR_A 1341, UMR_S 1241, F-35000, Rennes, France
| | - Thomas Gicquel
- INSERM, Univ Rennes, INRAE, Institut NUMECAN (Nutrition Metabolisms and Cancer) UMR_A 1341, UMR_S 1241, F-35000, Rennes, France; CHU Rennes, Laboratoire de toxicologie médico-légale, F-35000, Rennes, France
| | - Bruno Mégarbane
- Department of Medical and Toxicological Critical Care, Lariboisière Hospital, University of Paris, INSERM, UMRS, 1144, Paris, France
| | - Bruno Clément
- INSERM, Univ Rennes, INRAE, Institut NUMECAN (Nutrition Metabolisms and Cancer) UMR_A 1341, UMR_S 1241, F-35000, Rennes, France
| | - Bernard Fromenty
- INSERM, Univ Rennes, INRAE, Institut NUMECAN (Nutrition Metabolisms and Cancer) UMR_A 1341, UMR_S 1241, F-35000, Rennes, France.
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91
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Cunningham RP, Sheldon RD, Rector RS. The Emerging Role of Hepatocellular eNOS in Non-alcoholic Fatty Liver Disease Development. Front Physiol 2020; 11:767. [PMID: 32719616 PMCID: PMC7350778 DOI: 10.3389/fphys.2020.00767] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Accepted: 06/11/2020] [Indexed: 12/29/2022] Open
Abstract
Non-alcoholic fatty liver disease (NAFLD) is comprised of a spectrum of liver injury ranging from excess fat accumulation in the liver (steatosis), to steatohepatitis (NASH), to its end stage of cirrhosis. A hallmark of NAFLD progression is the decline in function of hepatic mitochondria, although the mechanisms remain unresolved. Given the important role endothelial nitric oxide synthase (eNOS) plays in mitochondrial dynamics in other tissues, it has emerged as a potential mediator of maintaining mitochondrial function in the liver. In this mini review, we summarize the most relevant findings that extends current understanding of eNOS as a regulator of mitochondrial biogenesis, and identifies a potential additional role in mitochondrial turnover and attenuating inflammation during NAFLD development and progression.
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Affiliation(s)
- Rory P Cunningham
- Research Service, Harry S. Truman Memorial Veterans' Hospital, Columbia, MO, United States.,Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, MO, United States
| | - Ryan D Sheldon
- Metabolic and Nutritional Programming, Center for Cancer and Cell Biology, Van Andel Institute, Grand Rapids, MI, United States
| | - R Scott Rector
- Research Service, Harry S. Truman Memorial Veterans' Hospital, Columbia, MO, United States.,Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, MO, United States.,Medicine-Division of Gastroenterology and Hepatology, University of Missouri, Columbia, MO, United States
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92
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Mey JT, Erickson ML, Axelrod CL, King WT, Flask CA, McCullough AJ, Kirwan JP. β-Hydroxybutyrate is reduced in humans with obesity-related NAFLD and displays a dose-dependent effect on skeletal muscle mitochondrial respiration in vitro. Am J Physiol Endocrinol Metab 2020; 319:E187-E195. [PMID: 32396388 PMCID: PMC7468782 DOI: 10.1152/ajpendo.00058.2020] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Nonalcoholic fatty liver disease (NAFLD) is characterized by hepatic fat accumulation and impaired insulin sensitivity. Reduced hepatic ketogenesis may promote these pathologies, but data are inconclusive in humans and the link between NAFLD and reduced insulin sensitivity remains obscure. We investigated individuals with obesity-related NAFLD and hypothesized that β-hydroxybutyrate (βOHB; the predominant ketone species) would be reduced and related to hepatic fat accumulation and insulin sensitivity. Furthermore, we hypothesized that ketones would impact skeletal muscle mitochondrial respiration in vitro. Hepatic fat was assessed by 1H-MRS in 22 participants in a parallel design, case control study [Control: n = 7, age 50 ± 6 yr, body mass index (BMI) 30 ± 1 kg/m2; NAFLD: n = 15, age 57 ± 3 yr, BMI 35 ± 1 kg/m2]. Plasma assessments were conducted in the fasted state. Whole body insulin sensitivity was determined by the gold-standard hyperinsulinemic-euglycemic clamp. The effect of ketone dose (0.5-5.0 mM) on mitochondrial respiration was conducted in human skeletal muscle cell culture. Fasting βOHB, a surrogate measure of hepatic ketogenesis, was reduced in NAFLD (-15.6%, P < 0.01) and correlated negatively with liver fat (r2 = 0.21, P = 0.03) and positively with insulin sensitivity (r2 = 0.30, P = 0.01). Skeletal muscle mitochondrial oxygen consumption increased with low-dose ketones, attributable to increases in basal respiration (135%, P < 0.05) and ATP-linked oxygen consumption (136%, P < 0.05). NAFLD pathophysiology includes impaired hepatic ketogenesis, which is associated with hepatic fat accumulation and impaired insulin sensitivity. This reduced capacity to produce ketones may be a potential link between NAFLD and NAFLD-associated reductions in whole body insulin sensitivity, whereby ketone concentrations impact skeletal muscle mitochondrial respiration.
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Affiliation(s)
- Jacob T Mey
- Integrated Physiology and Molecular Medicine, Pennington Biomedical Research Center, Baton Rouge, Louisiana
- Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio
| | - Melissa L Erickson
- Integrated Physiology and Molecular Medicine, Pennington Biomedical Research Center, Baton Rouge, Louisiana
- Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio
| | - Christopher L Axelrod
- Integrated Physiology and Molecular Medicine, Pennington Biomedical Research Center, Baton Rouge, Louisiana
- Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio
- Translational Services, Pennington Biomedical Research Center, Baton Rouge, Louisiana
| | - William T King
- Integrated Physiology and Molecular Medicine, Pennington Biomedical Research Center, Baton Rouge, Louisiana
| | - Chris A Flask
- Radiology and Biomedical Engineering, Case Western Reserve University School of Medicine, Cleveland, Ohio
| | | | - John P Kirwan
- Integrated Physiology and Molecular Medicine, Pennington Biomedical Research Center, Baton Rouge, Louisiana
- Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio
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93
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Thyfault JP, Rector RS. Exercise Combats Hepatic Steatosis: Potential Mechanisms and Clinical Implications. Diabetes 2020; 69:517-524. [PMID: 32198195 PMCID: PMC7085252 DOI: 10.2337/dbi18-0043] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Accepted: 01/22/2020] [Indexed: 12/17/2022]
Abstract
Hepatic steatosis, the excess storage of intrahepatic lipids, is a rampant clinical problem associated with the obesity epidemic. Hepatic steatosis is linked to increased risk for insulin resistance, type 2 diabetes, and cardiovascular and advanced liver disease. Accumulating evidence shows that physical activity, exercise, and aerobic capacity have profound effects on regulating intrahepatic lipids and mediating susceptibility for hepatic steatosis. Moreover, exercise can effectively reduce hepatic steatosis independent of changes in body mass. In this perspective, we highlight 1) the relationship between obesity and metabolic pathways putatively driving hepatic steatosis compared with changes induced by exercise; 2) the impact of physical activity, exercise, and aerobic capacity compared with caloric restriction on regulating intrahepatic lipids and steatosis risk; 3) the effects of exercise training (modalities, volume, intensity) for treatment of hepatic steatosis, and 4) evidence for a sustained protection against steatosis induced by exercise. Overall, evidence clearly indicates that exercise powerfully regulates intrahepatic storage of fat and risk for steatosis.
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Affiliation(s)
- John P Thyfault
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, KS
- Research Service, Kansas City VA Medical Center, Kansas City, MO
- Center for Children's Healthy Lifestyles and Nutrition, Children's Mercy Hospital, Kansas City, MO
| | - R Scott Rector
- Division of Gastroenterology and Hepatology, Department of Medicine, and Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, MO
- Research Service, Harry S. Truman Memorial VA Medical Center, Columbia, MO
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94
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Finan B, Capozzi ME, Campbell JE. Repositioning Glucagon Action in the Physiology and Pharmacology of Diabetes. Diabetes 2020; 69:532-541. [PMID: 31178432 PMCID: PMC7085250 DOI: 10.2337/dbi19-0004] [Citation(s) in RCA: 70] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Accepted: 05/30/2019] [Indexed: 01/03/2023]
Abstract
Glucagon is historically described as the counterregulatory hormone to insulin, induced by fasting/hypoglycemia to raise blood glucose through action mediated in the liver. However, it is becoming clear that the biology of glucagon is much more complex and extends beyond hepatic actions to exert control on glucose metabolism. We discuss the inconsistencies with the canonical view that glucagon is primarily a hyperglycemic agent driven by fasting/hypoglycemia and highlight the recent advances that have reshaped the metabolic role of glucagon. These concepts are placed within the context of both normal physiology and the pathophysiology of disease and then extended to discuss emerging strategies that incorporate glucagon agonism in the pharmacology of treating diabetes.
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Affiliation(s)
- Brian Finan
- Novo Nordisk Research Center, Indianapolis, IN
| | - Megan E Capozzi
- Duke Molecular Physiology Institute, Duke University, Durham, NC
| | - Jonathan E Campbell
- Duke Molecular Physiology Institute, Duke University, Durham, NC
- Division of Endocrinology, Department of Medicine, Duke University, Durham, NC
- Department of Pharmacology and Cancer Biology, Duke University, Durham, NC
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95
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Lu X, Dong Y, Jian Z, Li Q, Gong L, Tang L, Zhou X, Liu M. Systematic Investigation of the Effects of Long-Term Administration of a High-Fat Diet on Drug Transporters in the Mouse Liver, Kidney and Intestine. Curr Drug Metab 2020; 20:742-755. [PMID: 31475894 DOI: 10.2174/1389200220666190902125435] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 07/10/2019] [Accepted: 08/13/2019] [Indexed: 01/17/2023]
Abstract
BACKGROUND Long-term intake of a high-fat diet is a crucial factor contributing to obesity, which has become a global public health problem. Progressive obesity subsequently leads to hepatic injury, renal damage and intestinal atrophy. Transporters expressed in the liver, kidney and intestine play important roles in the deposition of nutrients and drugs, but researchers have not clearly determined whether/how the expression of transporters changes after long-term administration of a High-Fat Diet (HFD). This study aims to explore the effects of the long-term administration of a HFD on the expression of drug transporters in the liver, kidney and intestine in mice and to provide useful information for medical applications in the clinic. METHODS Male C57BL/6J mice were fed either a basal diet or HFD for 24 weeks, and oral glucose tolerance tests were performed after 3, 11 and 23 weeks. Serum was obtained to measure lipid metabolism, inflammatory mediators, renal function and hepatic function. Adipose tissues, kidney, pancreas and liver were collected for hematoxylin and eosin (H&E) staining after 4, 12 and 24 weeks. The mRNA and proteins expression of drug transporters in the liver, kidney and intestine were detected using real-time PCR and western blot, respectively. RESULTS Compared with the control group, long-term HFD administration significantly increased the adipose index. The serum lipid levels, including Total Cholesterol (TC), Triglyceride (TG), and Low-Density Lipoprotein Cholesterol (LDL-C), as well as the levels of the inflammatory cytokines Interleukin-10 (IL-10) and tumor necrosis factor-α (TNF-α) were significantly elevated in HFD-induced obese mice. H&E staining revealed pathological changes in the adipose cells, liver, kidney and pancreas from the obese group following the long-term administration of the HFD. The liver of the obese group presented increased mRNA expression of the efflux transporter Mrp2 and uptake transporter Oat2 at 24 weeks. The relative expression of Oat2 increased 4.08-fold and the protein expression of Oat2 was upregulated at 24 weeks in HFD-fed mice, while the mRNA expression of the uptake transporters Oct1, Oatp1b2 and Oatp1a4 decreased by 79%, 61% and 19%, respectively. The protein expression of Oct1 was significantly downregulated in obese mice at 12 weeks. The mRNA expression of the efflux transporter Mdr1a was significantly reduced in HFD-fed mice compared with the control group at 24 weeks. Western blot showed that the trend of protein level of Mdr1 was consistent with the mRNA expression. In the kidney, the level of the Oct2 mRNA increased 1.92- and 2.46-fold at 4 and 12 weeks in HFD-fed mice, respectively. The expression of the Oat1 and Oat3 mRNAs was markedly downregulated in the kidneys of mice with HFD-induced obesity at 4 weeks. The decrease of 72% and 21% in Mdr1a mRNA expression was observed in the obese model at 4 weeks and 12 weeks, respectively. Western blot showed that the protein levels of Mdr1 and Oat1 were consistent with the mRNA expression. The qPCR experiments showed a 2.87-fold increase in Bcrp mRNA expression at 24 weeks, and the expression of the Pept1 mRNA increased 2.84-fold in intestines of obese mice subjected to long-term administration of the HFD compared with control mice at 12 weeks. Western blot showed that the trend of protein levels of Mdr1 and Mrp2 were consistent with the mRNA expression. CONCLUSION The expression of uptake and efflux transporters mRNAs and protein levels were altered in obese mice compared with control mice, providing scientific evidence for future medical applications in the clinic.
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Affiliation(s)
- Xianyuan Lu
- Guangdong Provincial Key Laboratory of New Drug Screening, School of Pharmaceutical Sciences, Southern Medical University, Guangzhou 510515, Guangdong, China
| | - Yaqian Dong
- Guangdong Provincial Key Laboratory of New Drug Screening, School of Pharmaceutical Sciences, Southern Medical University, Guangzhou 510515, Guangdong, China
| | - Zhichao Jian
- Guangdong Provincial Key Laboratory of New Drug Screening, School of Pharmaceutical Sciences, Southern Medical University, Guangzhou 510515, Guangdong, China
| | - Qingyun Li
- Guangdong Provincial Key Laboratory of New Drug Screening, School of Pharmaceutical Sciences, Southern Medical University, Guangzhou 510515, Guangdong, China
| | - Linna Gong
- Guangdong Provincial Key Laboratory of New Drug Screening, School of Pharmaceutical Sciences, Southern Medical University, Guangzhou 510515, Guangdong, China
| | - Lan Tang
- Guangdong Provincial Key Laboratory of New Drug Screening, School of Pharmaceutical Sciences, Southern Medical University, Guangzhou 510515, Guangdong, China
| | - Xuefeng Zhou
- CAS Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China
| | - Menghua Liu
- Guangdong Provincial Key Laboratory of New Drug Screening, School of Pharmaceutical Sciences, Southern Medical University, Guangzhou 510515, Guangdong, China
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Staňková P, Kučera O, Peterová E, Lotková H, Maseko TE, Nožičková K, Červinková Z. Adaptation of Mitochondrial Substrate Flux in a Mouse Model of Nonalcoholic Fatty Liver Disease. Int J Mol Sci 2020; 21:ijms21031101. [PMID: 32046101 PMCID: PMC7036817 DOI: 10.3390/ijms21031101] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Revised: 02/02/2020] [Accepted: 02/05/2020] [Indexed: 12/30/2022] Open
Abstract
Maladaptation of mitochondrial oxidative flux seems to be a considerable feature of nonalcoholic fatty liver disease (NAFLD). The aim of this work was to induce NAFLD in mice fed a Western-style diet (WD) and to evaluate liver mitochondrial functions. Experiments were performed on male C57BL/6J mice fed with a control diet or a WD for 24 weeks. Histological changes in liver and adipose tissue as well as hepatic expression of fibrotic and inflammatory genes and proteins were evaluated. The mitochondrial respiration was assessed by high-resolution respirometry. Oxidative stress was evaluated by measuring lipoperoxidation, glutathione, and reactive oxygen species level. Feeding mice a WD induced adipose tissue inflammation and massive liver steatosis accompanied by mild inflammation and fibrosis. We found decreased succinate-activated mitochondrial respiration and decreased succinate dehydrogenase (SDH) activity in the mice fed a WD. The oxidative flux with other substrates was not affected. We observed increased ketogenic capacity, but no impact on the capacity for fatty acid oxidation. We did not confirm the presence of oxidative stress. Mitochondria in this stage of the disease are adapted to increased substrate flux. However, inhibition of SDH can lead to the accumulation of succinate, an important signaling molecule associated with inflammation, fibrosis, and carcinogenesis.
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Affiliation(s)
- Pavla Staňková
- Department of Physiology, Faculty of Medicine in Hradec Králové, Charles University, Šimkova 870, 500 03 Hradec Králové, Czech Republic; (P.S.); (H.L.); (T.E.M.); (K.N.); (Z.Č.)
| | - Otto Kučera
- Department of Physiology, Faculty of Medicine in Hradec Králové, Charles University, Šimkova 870, 500 03 Hradec Králové, Czech Republic; (P.S.); (H.L.); (T.E.M.); (K.N.); (Z.Č.)
- Correspondence: ; Tel.: +420-495-816-186
| | - Eva Peterová
- Department of Medical Biochemistry, Faculty of Medicine in Hradec Králové, Charles University, Šimkova 870, 500 03 Hradec Králové, Czech Republic;
| | - Halka Lotková
- Department of Physiology, Faculty of Medicine in Hradec Králové, Charles University, Šimkova 870, 500 03 Hradec Králové, Czech Republic; (P.S.); (H.L.); (T.E.M.); (K.N.); (Z.Č.)
| | - Tumisang Edward Maseko
- Department of Physiology, Faculty of Medicine in Hradec Králové, Charles University, Šimkova 870, 500 03 Hradec Králové, Czech Republic; (P.S.); (H.L.); (T.E.M.); (K.N.); (Z.Č.)
| | - Kateřina Nožičková
- Department of Physiology, Faculty of Medicine in Hradec Králové, Charles University, Šimkova 870, 500 03 Hradec Králové, Czech Republic; (P.S.); (H.L.); (T.E.M.); (K.N.); (Z.Č.)
| | - Zuzana Červinková
- Department of Physiology, Faculty of Medicine in Hradec Králové, Charles University, Šimkova 870, 500 03 Hradec Králové, Czech Republic; (P.S.); (H.L.); (T.E.M.); (K.N.); (Z.Č.)
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97
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Wang HW, Liu J, Wei SS, Zhao WP, Zhu SQ, Zhou BH. Mitochondrial respiratory chain damage and mitochondrial fusion disorder are involved in liver dysfunction of fluoride-induced mice. CHEMOSPHERE 2020; 241:125099. [PMID: 31629238 DOI: 10.1016/j.chemosphere.2019.125099] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Revised: 10/08/2019] [Accepted: 10/09/2019] [Indexed: 06/10/2023]
Abstract
Our previous study showed that excessive fluoride (F) intake can induce liver dysfunction. The aim of this study was to investigate the mechanisms of F-induced mitochondrial damage resulting in liver dysfunction. Damaged mitochondrial ultrastructure and state of liver cells were estimated by TEM, TUNEL staining and BrdU measurement. The ROS level and ATP content in the liver tissue were measured by ELISA kit. Meanwhile, optic atrophy (OPA1), mitofusin-1 (Mfn1), NDUFV2, SDHA, CYC1, and COX Ⅳ expression levels were measured through real-time PCR and Western-blot. Results showed that the ROS level increased, thereby resulting in mitochondrial ultrastructure damage and abundant liver cells presented evident apoptotic characteristics after F treatment. Decreased ATP content and the abnormal expression of OPA1, Mfn1, NDUFV2, SDHA, CYC1, and COX Ⅳ of the liver tissue were observed. In conclusion, excessive F-induced mitochondrial respiratory chain damaged and mitochondrial fusion disorder resulted in liver dysfunction.
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Affiliation(s)
- Hong-Wei Wang
- Henan Key Laboratory of Environmental and Animal Product Safety, Henan University of Science and Technology, Luoyang, 471000, Henan, People's Republic of China
| | - Jing Liu
- Henan Key Laboratory of Environmental and Animal Product Safety, Henan University of Science and Technology, Luoyang, 471000, Henan, People's Republic of China
| | - Shan-Shan Wei
- Henan Key Laboratory of Environmental and Animal Product Safety, Henan University of Science and Technology, Luoyang, 471000, Henan, People's Republic of China
| | - Wen-Peng Zhao
- Henan Key Laboratory of Environmental and Animal Product Safety, Henan University of Science and Technology, Luoyang, 471000, Henan, People's Republic of China
| | - Shi-Quan Zhu
- Henan Key Laboratory of Environmental and Animal Product Safety, Henan University of Science and Technology, Luoyang, 471000, Henan, People's Republic of China
| | - Bian-Hua Zhou
- Henan Key Laboratory of Environmental and Animal Product Safety, Henan University of Science and Technology, Luoyang, 471000, Henan, People's Republic of China.
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Hepatic Mitochondrial Oxidative Metabolism and Lipogenesis Synergistically Adapt to Mediate Healthy Embryonic-to-Neonatal Transition in Chicken. Sci Rep 2019; 9:20167. [PMID: 31882889 PMCID: PMC6934531 DOI: 10.1038/s41598-019-56715-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Accepted: 12/05/2019] [Indexed: 01/15/2023] Open
Abstract
During the normal embryonic-to-neonatal development, the chicken liver is subjected to intense lipid burden from high rates of yolk-lipid oxidation and also from the accumulation of the yolk-derived and newly synthesized lipids from carbohydrates. High rates of hepatic lipid oxidation and lipogenesis are also central features of non-alcoholic fatty liver disease (NAFLD) in both rodents and humans, but is associated with impaired insulin signaling, dysfunctional mitochondrial energetics and oxidative stress. However, these adverse effects are not apparent in the liver of embryonic and neonatal chicken, despite lipid burden. Utilizing comprehensive metabolic profiling, we identify that steady induction of hepatic mitochondrial tricarboxylic acid (TCA) cycle and lipogenesis are central features of embryonic-to-neonatal transition. More importantly, the induction of TCA cycle and lipogenesis occurred together with the downregulation of hepatic β-oxidation and ketogenesis in the neonatal chicken. This synergistic remodeling of hepatic metabolic networks blunted inflammatory onset, prevented accumulation of lipotoxic intermediates (ceramides and diacylglycerols) and reduced reactive oxygen species production during embryonic-to-neonatal development. This dynamic remodeling of hepatic mitochondrial oxidative flux and lipogenesis aids in the healthy embryonic-to-neonatal transition in chicken. This natural physiological system could help identify mechanisms regulating mitochondrial function and lipogenesis, with potential implications towards treatment of NAFLD.
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Léveillé M, Estall JL. Mitochondrial Dysfunction in the Transition from NASH to HCC. Metabolites 2019; 9:E233. [PMID: 31623280 PMCID: PMC6836234 DOI: 10.3390/metabo9100233] [Citation(s) in RCA: 62] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Revised: 09/26/2019] [Accepted: 10/11/2019] [Indexed: 02/06/2023] Open
Abstract
The liver constantly adapts to meet energy requirements of the whole body. Despite its remarkable adaptative capacity, prolonged exposure of liver cells to harmful environmental cues (such as diets rich in fat, sugar, and cholesterol) results in the development of chronic liver diseases (including non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH)) that can progress to hepatocellular carcinoma (HCC). The pathogenesis of these diseases is extremely complex, multifactorial, and poorly understood. Emerging evidence suggests that mitochondrial dysfunction or maladaptation contributes to detrimental effects on hepatocyte bioenergetics, reactive oxygen species (ROS) homeostasis, endoplasmic reticulum (ER) stress, inflammation, and cell death leading to NASH and HCC. The present review highlights the potential contribution of altered mitochondria function to NASH-related HCC and discusses how agents targeting this organelle could provide interesting treatment strategies for these diseases.
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Affiliation(s)
- Mélissa Léveillé
- Institut de Recherches Cliniques de Montréal (IRCM), Montreal, Quebec, QC H2W 1R7, Canada.
- Faculty of Medicine, University of Montreal, Montreal, Quebec, QC H3G 2M1, Canada.
| | - Jennifer L Estall
- Institut de Recherches Cliniques de Montréal (IRCM), Montreal, Quebec, QC H2W 1R7, Canada.
- Faculty of Medicine, University of Montreal, Montreal, Quebec, QC H3G 2M1, Canada.
- Division of Experimental Medicine, McGill University, Montreal, Quebec, QC H4A 3J1, Canada.
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