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Mellemkjær A, Kjær MB, Haldrup D, Grønbæk H, Thomsen KL. Management of cardiovascular risk in patients with metabolic dysfunction-associated steatotic liver disease. Eur J Intern Med 2024; 122:28-34. [PMID: 38008609 DOI: 10.1016/j.ejim.2023.11.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/24/2023] [Revised: 11/06/2023] [Accepted: 11/08/2023] [Indexed: 11/28/2023]
Abstract
The novel term Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD) is proposed to replace non-alcoholic fatty liver disease (NAFLD) to highlight the close association with the metabolic syndrome. MASLD encompasses patients with liver steatosis and at least one of five cardiometabolic risk factors which implies that these patients are at increased risk of cardiovascular disease (CVD). Indeed, the prevalence of CVD in MASLD patients is increased and CVD is recognized as the most common cause of death in MASLD patients. We here present an update on the pathophysiology of CVD in MASLD, discuss the risk factors, and suggest screening for CVD in patients with MASLD. Currently, there is no FDA-approved pharmacological treatment for MASLD, and no specific treatment recommended for CVD in patients with MASLD. Thus, the treatment strategy is based on weight loss and a reduction and treatment of CVD risk factors. We recommend screening of MASLD patients for CVD using the SCORE2 system with guidance to specific treatment algorithms. In all patients with CVD risk factors, lifestyle intervention to induce weight loss through diet and exercise is recommended. Especially a Mediterranean diet may improve hyperlipidemia and if further treatment is needed, statins should be used as first-line treatment. Further, anti-hypertensive drugs should be used to treat hypertension. With the epidemic of obesity and type 2 diabetes mellitus (T2DM) the risk of MASLD and CVD is expected to increase, and preventive measures, screening, and effective treatments are highly needed to reduce morbidity and mortality in MASLD patients.
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Affiliation(s)
- Anders Mellemkjær
- Department of Hepatology & Gastroenterology, Aarhus University Hospital, Aarhus, Denmark; Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Mikkel Breinholt Kjær
- Department of Hepatology & Gastroenterology, Aarhus University Hospital, Aarhus, Denmark; Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - David Haldrup
- Department of Hepatology & Gastroenterology, Aarhus University Hospital, Aarhus, Denmark; Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Henning Grønbæk
- Department of Hepatology & Gastroenterology, Aarhus University Hospital, Aarhus, Denmark; Department of Clinical Medicine, Aarhus University, Aarhus, Denmark.
| | - Karen Louise Thomsen
- Department of Hepatology & Gastroenterology, Aarhus University Hospital, Aarhus, Denmark; Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
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Syed-Abdul MM. Lipid Metabolism in Metabolic-Associated Steatotic Liver Disease (MASLD). Metabolites 2023; 14:12. [PMID: 38248815 PMCID: PMC10818604 DOI: 10.3390/metabo14010012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2023] [Revised: 12/20/2023] [Accepted: 12/21/2023] [Indexed: 01/23/2024] Open
Abstract
Metabolic-associated steatotic liver disease (MASLD) is a cluster of pathological conditions primarily developed due to the accumulation of ectopic fat in the hepatocytes. During the severe form of the disease, i.e., metabolic-associated steatohepatitis (MASH), accumulated lipids promote lipotoxicity, resulting in cellular inflammation, oxidative stress, and hepatocellular ballooning. If left untreated, the advanced form of the disease progresses to fibrosis of the tissue, resulting in irreversible hepatic cirrhosis or the development of hepatocellular carcinoma. Although numerous mechanisms have been identified as significant contributors to the development and advancement of MASLD, altered lipid metabolism continues to stand out as a major factor contributing to the disease. This paper briefly discusses the dysregulation in lipid metabolism during various stages of MASLD.
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Affiliation(s)
- Majid Mufaqam Syed-Abdul
- Toronto General Hospital Research Institute, University Health Network, University of Toronto, Toronto, ON M5G 1L7, Canada
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3
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Cook JR, Hawkins MA, Pajvani UB. Liver insulinization as a driver of triglyceride dysmetabolism. Nat Metab 2023; 5:1101-1110. [PMID: 37460842 DOI: 10.1038/s42255-023-00843-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Accepted: 06/13/2023] [Indexed: 07/26/2023]
Abstract
Metabolic dysfunction-associated fatty liver disease (MAFLD) is an increasingly prevalent fellow traveller with the insulin resistance that underlies type 2 diabetes mellitus. However, the mechanistic connection between MAFLD and impaired insulin action remains unclear. In this Perspective, we review data from humans to elucidate insulin's aetiological role in MAFLD. We focus particularly on the relative preservation of insulin's stimulation of triglyceride (TG) biosynthesis despite its waning ability to curb hepatic glucose production (HGP). To explain this apparent 'selective insulin resistance', we propose that hepatocellular processes that lead to TG accumulation require less insulin signal transduction, or 'insulinization,' than do those that regulate HGP. As such, mounting hyperinsulinaemia that barely compensates for aberrant HGP in insulin-resistant states more than suffices to maintain hepatic TG biosynthesis. Thus, even modestly elevated or context-inappropriate insulin levels, when sustained day and night within a heavily pro-lipogenic metabolic milieu, may translate into substantial cumulative TG biosynthesis in the insulin-resistant state.
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Affiliation(s)
- Joshua R Cook
- Naomi Berrie Diabetes Center, Division of Endocrinology, Diabetes & Metabolism, Department of Medicine, Columbia University College of Physicians & Surgeons, New York City, NY, USA.
| | - Meredith A Hawkins
- Diabetes Research and Training Center, Division of Endocrinology, Department of Medicine, Albert Einstein College of Medicine, New York City, NY, USA
| | - Utpal B Pajvani
- Naomi Berrie Diabetes Center, Division of Endocrinology, Diabetes & Metabolism, Department of Medicine, Columbia University College of Physicians & Surgeons, New York City, NY, USA
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Risikesan J, Heebøll S, Kumarathas I, Funck KL, Søndergaard E, Johansen RF, Ringgaard S, Tolbod LP, Johannsen M, Kanstrup HL, Grønbæk H, Frystyk J, Gormsen LC, Nielsen S. Exercise increases myocardial free fatty acid oxidation in subjects with metabolic dysfunction-associated fatty liver disease. Atherosclerosis 2023; 372:10-18. [PMID: 37011565 DOI: 10.1016/j.atherosclerosis.2023.03.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 03/01/2023] [Accepted: 03/22/2023] [Indexed: 04/05/2023]
Abstract
BACKGROUND AND AIMS Metabolic dysfunction-associated fatty liver disease (MAFLD) is associated with dyslipidemia and may promote cardiac lipotoxicity. Myocardial free fatty acids (FFA) oxidation (MOFFA) is normal in pre-diabetes, but reduced in heart failure. We hypothesized that during exercise MOFFA, very low-density lipoprotein triglycerides (VLDL-TG) secretion, hepatic FFA utilization, and lactate production differ among obese subjects with and without MAFLD. METHODS Nine obese subjects with MAFLD and 8 matched subjects without MAFLD (Control) without a history of heart failure and cardiovascular disease were compared before and after 90-min exercise at 50% Peak oxygen consumption. Basal and exercise induced cardiac and hepatic FFA oxidation, uptake and re-esterification and VLDL-TG secretion were measured using [11C]palmitate positron-emission tomography and [1-14C]VLDL-TG. RESULTS In the heart, increased MOFFA was observed after exercise in MAFLD, whereas MOFFA decreased in Control (basal vs exercise, MAFLD: 4.1 (0.8) vs 4.8 (0.8) μmol·100 ml-1 min-1; Control: 4.9 (1.8) vs 4.0 (1.1); μmol·100 ml-1 min-1, mean (SD), p < 0.048). Hepatic FFA fluxes were significantly lower in MAFLD than Control and increased ≈ two-fold in both groups. VLDL-TG secretion was 50% greater in MAFLD at rest and similarly suppressed during exercise. Plasma lactate increased significantly less in MAFLD than Control during exercise. CONCLUSIONS Using robust tracer-techniques we found that obese subjects with MAFLD do not downregulate MOFFA during exercise compared to Control, possibly due to diminished lactate supply. Hepatic FFA fluxes are significantly lower in MAFLD than Control, but increase similarly with exercise. VLDL-TG export remains greater in MAFLD compared to Control. Basal and post-exercise myocardial and hepatic FFA, VLDL-TG and lactate metabolism is abnormal in subjects with MAFLD compared to Control.
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Affiliation(s)
| | - Sara Heebøll
- Steno Diabetes Center Aarhus, Aarhus University Hospital (AUH), Aarhus, Denmark; Department of Endocrinology and Internal Medicine, AUH, Aarhus, Denmark
| | | | - Kristian L Funck
- Department of Endocrinology and Internal Medicine, AUH, Aarhus, Denmark
| | - Esben Søndergaard
- Steno Diabetes Center Aarhus, Aarhus University Hospital (AUH), Aarhus, Denmark
| | - Rakel F Johansen
- Steno Diabetes Center Aarhus, Aarhus University Hospital (AUH), Aarhus, Denmark
| | | | - Lars P Tolbod
- Department of Nuclear Medicine and PET Centre, AUH, Aarhus, Denmark
| | - Mogens Johannsen
- Section for Forensic Chemistry, Department of Forensic Medicine, AUH, Aarhus, Denmark
| | | | - Henning Grønbæk
- Department of Hepatology and Gastroenterology, AUH, Aarhus, Denmark; Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Jan Frystyk
- Department of Endocrinology, Odense University Hospital, Odense, Denmark
| | - Lars C Gormsen
- Department of Nuclear Medicine and PET Centre, AUH, Aarhus, Denmark; Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Søren Nielsen
- Steno Diabetes Center Aarhus, Aarhus University Hospital (AUH), Aarhus, Denmark; Department of Clinical Medicine, Aarhus University, Aarhus, Denmark.
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Ahmed ES, Mohamed HE, Farrag MA. Luteolin loaded on zinc oxide nanoparticles ameliorates non-alcoholic fatty liver disease associated with insulin resistance in diabetic rats via regulation of PI3K/AKT/FoxO1 pathway. Int J Immunopathol Pharmacol 2022; 36:3946320221137435. [PMID: 36319192 PMCID: PMC9630902 DOI: 10.1177/03946320221137435] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
OBJECTIVE Non-alcoholic fatty liver disease (NAFLD) is a worldwide health problem with high prevalence and morbidity associated with obesity, insulin resistance, type 2 diabetes mellitus (T2DM), and dyslipidemia. Nano-formulation of luteolin with Zn oxide in the form of Lut/ZnO NPs may improve the anti-diabetic property of each alone and ameliorate the insulin resistance thus management of NAFLD. This study aimed to measure the efficiency of Lut/ZnO NPs against insulin resistance coupled with NAFLD and T2DM. METHODS A diabetic rat model with NAFLD was induced by a high-fat diet and streptozotocin (30 mg/kg I.P). Serum diabetogenic markers levels, lipid profile, and activity of liver enzymes were measured beside liver oxidative stress markers. Moreover, the hepatic expressions of PI3K/AKT/FoxO1/SERBP1c as well as heme oxygenase-1 were measured beside the histopathological examination. RESULTS Lut/ZnO NPs treatment effectively reduced hyperglycemia, hyperinsulinemia, and ameliorated insulin resistance. Additionally, Lut/ZnO NPs improved the hepatic functions, the antioxidant system, and reduced the oxidative stress markers. Furthermore, the lipid load in the liver, as well as the circulating TG and TC, was minified via the suppression of lipogenesis and gluconeogenesis. Moreover, Lut/ZnO NPs activated the PI3K/AKT signaling pathway, hence inactivating FoxO1, therefore enhancing the hepatic cells' insulin sensitivity. CONCLUSION Lut/ZnO NPs have a hepatoprotective effect and may relieve the progression of NAFLD by alleviating insulin resistance, ameliorating the antioxidant status, and regulating the insulin signal pathway.
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Affiliation(s)
- Esraa Sa Ahmed
- Radiation Biology Research, National Center for Radiation Research and Technology, 68892Egyptian Atomic Energy Authority, Cairo, Egypt
| | - Hebatallah E Mohamed
- Radiation Biology Research, National Center for Radiation Research and Technology, 68892Egyptian Atomic Energy Authority, Cairo, Egypt
| | - Mostafa A Farrag
- Radiation Biology Research, National Center for Radiation Research and Technology, 68892Egyptian Atomic Energy Authority, Cairo, Egypt
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Heebøll S, Risikesan J, Ringgaard S, Kumarathas I, Sandahl TD, Grønbæk H, Søndergaard E, Nielsen S. Impaired Glucagon-Mediated Suppression of VLDL-Triglyceride Secretion in Individuals With Metabolic Dysfunction-Associated Fatty Liver Disease (MAFLD). Diabetes 2022; 71:2402-2411. [PMID: 36001750 PMCID: PMC9630084 DOI: 10.2337/db22-0313] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Accepted: 08/22/2022] [Indexed: 01/25/2023]
Abstract
Individuals with metabolic dysfunction-associated fatty liver disease (MAFLD) have elevated plasma lipids as well as glucagon, although glucagon suppresses hepatic VLDL-triglyceride (TG) secretion. We hypothesize that the sensitivity to glucagon in hepatic lipid metabolism is impaired in MAFLD. We recruited 11 subjects with severe MAFLD (MAFLD+), 10 with mild MAFLD (MAFLD-), and 7 overweight control (CON) subjects. We performed a pancreatic clamp with a somatostatin analog (octreotide) to suppress endogenous hormone production, combined with infusion of low-dose glucagon (0.65 ng/kg/min, t = 0-270 min, LowGlucagon), followed by high-dose glucagon (1.5 ng/kg/min, t = 270-450 min, HighGlucagon). VLDL-TG and glucose tracers were used to evaluate VLDL-TG kinetics and endogenous glucose production (EGP). HighGlucagon suppressed VLDL-TG secretion compared with LowGlucagon. This suppression was markedly attenuated in MAFLD subjects compared with CON subjects (MAFLD+: 13% ± [SEM] 5%; MAFLD-: 10% ± 3%; CON: 36% ± 7%, P < 0.01), with no difference between MAFLD groups. VLDL-TG concentration and VLDL-TG oxidation rate increased between LowGlucagon and HighGlucagon in MAFLD+ subjects compared with CON subjects. EGP transiently increased during HighGlucagon without any difference between the three groups. Individuals with MAFLD have a reduced sensitivity to glucagon in the hepatic TG metabolism, which could contribute to the dyslipidemia seen in MAFLD patients. ClinicalTrials.gov: NCT04042142.
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Affiliation(s)
- Sara Heebøll
- Department of Endocrinology and Internal Medicine, Aarhus University Hospital, Aarhus, Denmark
- Steno Diabetes Center Aarhus, Aarhus University Hospital, Aarhus, Denmark
- Corresponding author: Sara Heebøll,
| | - Jeyanthini Risikesan
- Steno Diabetes Center Aarhus, Aarhus University Hospital, Aarhus, Denmark
- Department of Internal Medicine, Regional Hospital Viborg, Viborg, Denmark
| | - Steffen Ringgaard
- Magnetic Resonance Research Centre, Aarhus University, Aarhus, Denmark
| | - Indumathi Kumarathas
- Steno Diabetes Center Aarhus, Aarhus University Hospital, Aarhus, Denmark
- Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Thomas D. Sandahl
- Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
- Department of Hepatology and Gastroenterology, Aarhus University Hospital, Aarhus, Denmark
| | - Henning Grønbæk
- Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
- Department of Hepatology and Gastroenterology, Aarhus University Hospital, Aarhus, Denmark
| | - Esben Søndergaard
- Department of Endocrinology and Internal Medicine, Aarhus University Hospital, Aarhus, Denmark
- Steno Diabetes Center Aarhus, Aarhus University Hospital, Aarhus, Denmark
- Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Søren Nielsen
- Steno Diabetes Center Aarhus, Aarhus University Hospital, Aarhus, Denmark
- Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
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7
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Bellanti F, Lo Buglio A, Dobrakowski M, Kasperczyk A, Kasperczyk S, Aich P, Singh SP, Serviddio G, Vendemiale G. Impact of sodium glucose cotransporter-2 inhibitors on liver steatosis/fibrosis/inflammation and redox balance in non-alcoholic fatty liver disease. World J Gastroenterol 2022; 28:3243-3257. [PMID: 36051336 PMCID: PMC9331534 DOI: 10.3748/wjg.v28.i26.3243] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Revised: 03/18/2022] [Accepted: 06/17/2022] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Sodium glucose cotransporter-2 inhibitors (SGLT2-I) are the most recently approved drugs for type 2 diabetes (T2D). Recent clinical trials of these compounds reported beneficial cardiovascular (CV) and renal outcomes. A major cause of vascular dysfunction and CV disease in diabetes is hyperglycemia associated with inflammation and oxidative stress. Pre-clinical studies demonstrated that SGLT2-I reduce glucotoxicity and promote anti-inflammatory effects by lowering oxidative stress.
AIM To investigate the effects of SGLT2-I on markers of oxidative stress, inflammation, liver steatosis, and fibrosis in patients of T2D with non-alcoholic fatty liver disease (NAFLD).
METHODS We referred fifty-two consecutive outpatients treated with metformin monotherapy and exhibiting poor glycemic control to our centre. We introduced the outpatients to an SGLT2-I (dapagliflozin, empagliflozin, or canagliflozin; n = 26) or a different hypoglycemic drug [other glucose-lowering drugs (OTHER), n = 26]. We evaluated circulating interleukins and serum hydroxynonenal (HNE)- or malondialdehyde (MDA)-protein adducts, fatty liver index (FLI), NAFLD fibrosis score, aspartate aminotransferase (AST)/alanine aminotransferase (ALT) ratio, AST-to-platelet-ratio index (APRI), and fibrosis-4 on the day before (T0) and following treatment for six months (T1). We also performed transient elastography at T0 and T1.
RESULTS Add-on therapy resulted in improved glycemic control and reduced fasting blood glucose in both groups. Of note, following treatment for six months, a reduction of FLI and APRI, as well as of the FibroScan result, was reported in patients treated with SGLT2-I, but not in the OTHER group; furthermore, in the SGLT2-I group, we reported lower circulating levels of interleukin (IL)-1β, IL-6, tumor necrosis factor, vascular endothelial growth factor, and monocyte chemoattractant protein-1, and higher levels of IL-4 and IL-10. We did not observe any modification in circulating interleukins in the OTHER group. Finally, serum HNE- and MDA-protein adducts decreased significantly in SGLT2-I rather than OTHER patients and correlated with liver steatosis and fibrosis scores.
CONCLUSION The present data indicate that treatment with SGLT2-I in patients with T2D and NAFLD is associated with improvement of liver steatosis and fibrosis markers and circulating pro-inflammatory and redox status, more than optimizing glycemic control.
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Affiliation(s)
- Francesco Bellanti
- Department of Medical and Surgical Sciences, University of Foggia, Foggia 71122, Italy
| | - Aurelio Lo Buglio
- Department of Medical and Surgical Sciences, University of Foggia, Foggia 71122, Italy
| | - Michał Dobrakowski
- Department of Biochemistry, Medical University of Silesia in Katowice, Zabrze 41-808, Poland
| | - Aleksandra Kasperczyk
- Department of Biochemistry, Medical University of Silesia in Katowice, Zabrze 41-808, Poland
| | - Sławomir Kasperczyk
- Department of Biochemistry, Medical University of Silesia in Katowice, Zabrze 41-808, Poland
| | - Palok Aich
- School of Biological Sciences, National Institute of Science Education and Research, Khurdha 752050, India
| | - Shivaram P Singh
- Department of Gastroenterology, SCB Medical College, Cuttack 753007, India
| | - Gaetano Serviddio
- Department of Medical and Surgical Sciences, University of Foggia, Foggia 71122, Italy
| | - Gianluigi Vendemiale
- Department of Medical and Surgical Sciences, University of Foggia, Foggia 71122, Italy
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Huang JK, Lee HC. Emerging Evidence of Pathological Roles of Very-Low-Density Lipoprotein (VLDL). Int J Mol Sci 2022; 23:ijms23084300. [PMID: 35457118 PMCID: PMC9031540 DOI: 10.3390/ijms23084300] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2022] [Revised: 04/10/2022] [Accepted: 04/11/2022] [Indexed: 12/18/2022] Open
Abstract
Embraced with apolipoproteins (Apo) B and Apo E, triglyceride-enriched very-low-density lipoprotein (VLDL) is secreted by the liver into circulation, mainly during post-meal hours. Here, we present a brief review of the physiological role of VLDL and a systemic review of the emerging evidence supporting its pathological roles. VLDL promotes atherosclerosis in metabolic syndrome (MetS). VLDL isolated from subjects with MetS exhibits cytotoxicity to atrial myocytes, induces atrial myopathy, and promotes vulnerability to atrial fibrillation. VLDL levels are affected by a number of endocrinological disorders and can be increased by therapeutic supplementation with cortisol, growth hormone, progesterone, and estrogen. VLDL promotes aldosterone secretion, which contributes to hypertension. VLDL induces neuroinflammation, leading to cognitive dysfunction. VLDL levels are also correlated with chronic kidney disease, autoimmune disorders, and some dermatological diseases. The extra-hepatic secretion of VLDL derived from intestinal dysbiosis is suggested to be harmful. Emerging evidence suggests disturbed VLDL metabolism in sleep disorders and in cancer development and progression. In addition to VLDL, the VLDL receptor (VLDLR) may affect both VLDL metabolism and carcinogenesis. Overall, emerging evidence supports the pathological roles of VLDL in multi-organ diseases. To better understand the fundamental mechanisms of how VLDL promotes disease development, elucidation of the quality control of VLDL and of the regulation and signaling of VLDLR should be indispensable. With this, successful VLDL-targeted therapies can be discovered in the future.
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Affiliation(s)
- Jih-Kai Huang
- Department of General Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung 80708, Taiwan;
| | - Hsiang-Chun Lee
- Division of Cardiology, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung 80708, Taiwan
- Department of Internal Medicine, School of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung 80708, Taiwan
- Lipid Science and Aging Research Center, College of Medicine, Kaohsiung Medical University, Kaohsiung 80708, Taiwan
- Institute of Medical Science and Technology, National Sun Yat-sen University, Kaohsiung 80708, Taiwan
- Graduate Institute of Animal Vaccine Technology, National Pingtung University of Science and Technology, Pingtung 91201, Taiwan
- Correspondence: ; Tel.: +886-7-3121101 (ext. 7741)
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Abstract
Triglycerides are critical lipids as they provide an energy source that is both compact and efficient. Due to its hydrophobic nature triglyceride molecules can pack together densely and so be stored in adipose tissue. To be transported in the aqueous medium of plasma, triglycerides have to be incorporated into lipoprotein particles along with other components such as cholesterol, phospholipid and associated structural and regulatory apolipoproteins. Here we discuss the physiology of normal triglyceride metabolism, and how impaired metabolism induces hypertriglyceridemia and its pathogenic consequences including atherosclerosis. We also discuss established and novel therapies to reduce triglyceride-rich lipoproteins.
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10
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Heeren J, Scheja L. Metabolic-associated fatty liver disease and lipoprotein metabolism. Mol Metab 2021; 50:101238. [PMID: 33892169 PMCID: PMC8324684 DOI: 10.1016/j.molmet.2021.101238] [Citation(s) in RCA: 191] [Impact Index Per Article: 63.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Revised: 04/01/2021] [Accepted: 04/15/2021] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Non-alcoholic fatty liver disease, or as recently proposed 'metabolic-associated fatty liver disease' (MAFLD), is characterized by pathological accumulation of triglycerides and other lipids in hepatocytes. This common disease can progress from simple steatosis to steatohepatitis, and eventually end-stage liver diseases. MAFLD is closely related to disturbances in systemic energy metabolism, including insulin resistance and atherogenic dyslipidemia. SCOPE OF REVIEW The liver is the central organ in lipid metabolism by secreting very low density lipoproteins (VLDL) and, on the other hand, by internalizing fatty acids and lipoproteins. This review article discusses recent research addressing hepatic lipid synthesis, VLDL production, and lipoprotein internalization as well as the lipid exchange between adipose tissue and the liver in the context of MAFLD. MAJOR CONCLUSIONS Liver steatosis in MAFLD is triggered by excessive hepatic triglyceride synthesis utilizing fatty acids derived from white adipose tissue (WAT), de novo lipogenesis (DNL) and endocytosed remnants of triglyceride-rich lipoproteins. In consequence of high hepatic lipid content, VLDL secretion is enhanced, which is the primary cause of complex dyslipidemia typical for subjects with MAFLD. Interventions reducing VLDL secretory capacity attenuate dyslipidemia while they exacerbate MAFLD, indicating that the balance of lipid storage versus secretion in hepatocytes is a critical parameter determining disease outcome. Proof of concept studies have shown that promoting lipid storage and energy combustion in adipose tissues reduces hepatic lipid load and thus ameliorates MAFLD. Moreover, hepatocellular triglyceride synthesis from DNL and WAT-derived fatty acids can be targeted to treat MAFLD. However, more research is needed to understand how individual transporters, enzymes, and their isoforms affect steatosis and dyslipidemia in vivo, and whether these two aspects of MAFLD can be selectively treated. Processing of cholesterol-enriched lipoproteins appears less important for steatosis. It may, however, modulate inflammation and consequently MAFLD progression.
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Affiliation(s)
- Joerg Heeren
- Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
| | - Ludger Scheja
- Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
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11
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Role of Insulin Resistance in MAFLD. Int J Mol Sci 2021; 22:ijms22084156. [PMID: 33923817 PMCID: PMC8072900 DOI: 10.3390/ijms22084156] [Citation(s) in RCA: 116] [Impact Index Per Article: 38.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Accepted: 04/14/2021] [Indexed: 12/17/2022] Open
Abstract
Many studies have reported that metabolic dysfunction is closely involved in the complex mechanism underlying the development of non-alcoholic fatty liver disease (NAFLD), which has prompted a movement to consider renaming NAFLD as metabolic dysfunction-associated fatty liver disease (MAFLD). Metabolic dysfunction in this context encompasses obesity, type 2 diabetes mellitus, hypertension, dyslipidemia, and metabolic syndrome, with insulin resistance as the common underlying pathophysiology. Imbalance between energy intake and expenditure results in insulin resistance in various tissues and alteration of the gut microbiota, resulting in fat accumulation in the liver. The role of genetics has also been revealed in hepatic fat accumulation and fibrosis. In the process of fat accumulation in the liver, intracellular damage as well as hepatic insulin resistance further potentiates inflammation, fibrosis, and carcinogenesis. Increased lipogenic substrate supply from other tissues, hepatic zonation of Irs1, and other factors, including ER stress, play crucial roles in increased hepatic de novo lipogenesis in MAFLD with hepatic insulin resistance. Herein, we provide an overview of the factors contributing to and the role of systemic and local insulin resistance in the development and progression of MAFLD.
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12
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Storck LJ, Meffert PJ, Rausch J, Gärtner S, Aghdassi AA, Kühn JP, Kraft M, Pietzner M, Lerch MM, Steveling A. Efficiency of a 15-Week Weight-Loss Program, Including a Low-Calorie Formula Diet, on Glycemic Control in Patients with Type 2 Diabetes Mellitus and Overweight or Obesity. Obes Facts 2021; 14:1-11. [PMID: 33601371 PMCID: PMC7983589 DOI: 10.1159/000511453] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Accepted: 09/01/2020] [Indexed: 12/13/2022] Open
Abstract
INTRODUCTION Patients who are overweight or obese have an increased risk of developing type 2 diabetes mellitus (T2DM). Weight loss can have a positive effect on glycemic control. OBJECTIVE We aimed to investigate glycemic control in patients with T2DM and overweight or obesity during a structured weight-loss program. METHODS This was a prospective, interventional study. We recruited 36 patients (14 men and 22 women) with a median age of 58.5 years and median body mass index (BMI) of 34.1, to a 15-week structured weight-loss program with a low-calorie (800 kcal) formula diet for 6 weeks. The primary end point, HbA1c level, and secondary end points, anthropometric data, medication, and safety, were assessed weekly. Laboratory values and quality of life were assessed at baseline and after 15 weeks. RESULTS HbA1c decreased from 7.3% at baseline to 6.5% at 15 weeks (p < 0.001), median body weight by 11.9 kg (p < 0.001), median BMI by 4.3 (p < 0.001) and median waist circumference by 11.0 cm (p < 0.001). Two participants discontinued insulin therapy, 4 could reduce their dosage of oral antidiabetic agents, and 6 completely discontinued their antidiabetic medication. Insulin dose decreased from 0.63 (0.38-0.89) to 0.39 (0.15-0.70) units/kg body weight (p < 0.001). No patient experienced hypoglycemic episodes or hospital emergency visits. Triglycerides and total cholesterol decreased as well as surrogate markers of liver function. However, the levels of high-density and low-density lipoprotein cholesterol (HDL-C and LDL-C) as well as uric acid remain unchanged. Regarding quality of life, the median physical health score increased from 44.5 (39.7-51.4) at baseline to 48.0 (43.1-55.3; p = 0.007), and the median mental health score decreased from 42.1 (36.1-46.7) to 37.4 (30.3-43.7; p = 0.004). CONCLUSIONS A structured weight-loss program is effective in the short term in reducing HbA1c, weight, and antidiabetic medication in patients with T2DM who are overweight or obese. Levels of HDL-C and LDL-C were not affected by short-term weight loss. The decline in mental health and the long-term effects of improved glycemic control require further trials.
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Affiliation(s)
- Lena J Storck
- Department of Medicine A, University Medicine Greifswald, Greifswald, Germany
- Department of Medicine, Kantonsspital Winterthur, Winterthur, Switzerland
| | - Peter J Meffert
- Institute of Community Medicine, University Medicine Greifswald, Greifswald, Germany
- Corvus, Statistical Consulting, Altkalen, Germany
| | - Janine Rausch
- Department of Medicine A, University Medicine Greifswald, Greifswald, Germany
| | - Simone Gärtner
- Department of Medicine A, University Medicine Greifswald, Greifswald, Germany
| | - Ali A Aghdassi
- Department of Medicine A, University Medicine Greifswald, Greifswald, Germany
| | - Jens-Peter Kühn
- Institute of Radiology and Neuroradiology, University Medicine Greifswald, Greifswald, Germany
- Institute of Radiology, Carl-Gustav Carus University Dresden, Dresden, Germany
| | - Matthias Kraft
- Department of Medicine A, University Medicine Greifswald, Greifswald, Germany
- Medizinische Klinik I, Vinzentius-Krankenhaus Landau, Landau, Germany
| | - Maik Pietzner
- Institute of Clinical Chemistry and Laboratory Medicine, University Medicine Greifswald, Greifswald, Germany
| | - Markus M Lerch
- Department of Medicine A, University Medicine Greifswald, Greifswald, Germany,
| | - Antje Steveling
- Department of Medicine A, University Medicine Greifswald, Greifswald, Germany
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Hajduch E, Lachkar F, Ferré P, Foufelle F. Roles of Ceramides in Non-Alcoholic Fatty Liver Disease. J Clin Med 2021; 10:jcm10040792. [PMID: 33669443 PMCID: PMC7920467 DOI: 10.3390/jcm10040792] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Revised: 02/10/2021] [Accepted: 02/12/2021] [Indexed: 12/12/2022] Open
Abstract
Non-alcoholic fatty liver disease is one of the most common chronic liver diseases, ranging from simple steatosis to steatohepatitis, fibrosis, and cirrhosis. Its prevalence is rapidly increasing and presently affects around 25% of the general population of Western countries, due to the obesity epidemic. Liver fat accumulation induces the synthesis of specific lipid species and particularly ceramides, a sphingolipid. In turn, ceramides have deleterious effects on hepatic metabolism, a phenomenon called lipotoxicity. We review here the evidence showing the role of ceramides in non-alcoholic fatty liver disease and the mechanisms underlying their effects.
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Affiliation(s)
- Eric Hajduch
- Centre de Recherche des Cordeliers, INSERM, Sorbonne Université, Université de Paris, 75006 Paris, France; (E.H.); (F.L.); (P.F.)
- Institute of Cardiometabolism and Nutrition (ICAN), Hôpital Pitié-Salpêtrière, AP-HP, 75013 Paris, France
| | - Floriane Lachkar
- Centre de Recherche des Cordeliers, INSERM, Sorbonne Université, Université de Paris, 75006 Paris, France; (E.H.); (F.L.); (P.F.)
- Institute of Cardiometabolism and Nutrition (ICAN), Hôpital Pitié-Salpêtrière, AP-HP, 75013 Paris, France
| | - Pascal Ferré
- Centre de Recherche des Cordeliers, INSERM, Sorbonne Université, Université de Paris, 75006 Paris, France; (E.H.); (F.L.); (P.F.)
- Institute of Cardiometabolism and Nutrition (ICAN), Hôpital Pitié-Salpêtrière, AP-HP, 75013 Paris, France
| | - Fabienne Foufelle
- Centre de Recherche des Cordeliers, INSERM, Sorbonne Université, Université de Paris, 75006 Paris, France; (E.H.); (F.L.); (P.F.)
- Institute of Cardiometabolism and Nutrition (ICAN), Hôpital Pitié-Salpêtrière, AP-HP, 75013 Paris, France
- Correspondence: ; Tel.: +33-1-44-27-24-25
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14
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Deprince A, Haas JT, Staels B. Dysregulated lipid metabolism links NAFLD to cardiovascular disease. Mol Metab 2020; 42:101092. [PMID: 33010471 PMCID: PMC7600388 DOI: 10.1016/j.molmet.2020.101092] [Citation(s) in RCA: 193] [Impact Index Per Article: 48.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 09/18/2020] [Accepted: 09/24/2020] [Indexed: 12/11/2022] Open
Abstract
Background Non-alcoholic fatty liver disease (NAFLD) is rapidly becoming a global health problem. Cardiovascular diseases (CVD) are the most common cause of mortality in NAFLD patients. NAFLD and CVD share several common risk factors including obesity, insulin resistance, and type 2 diabetes (T2D). Atherogenic dyslipidemia, characterized by plasma hypertriglyceridemia, increased small dense low-density lipoprotein (LDL) particles, and decreased high-density lipoprotein cholesterol (HDL-C) levels, is often observed in NAFLD patients. Scope of review In this review, we highlight recent epidemiological studies evaluating the link between NAFLD and CVD risk. We further focus on recent mechanistic insights into the links between NAFLD and altered lipoprotein metabolism. We also discuss current therapeutic strategies for NAFLD and their potential impact on NAFLD-associated CVD risk. Major conclusions Alterations in hepatic lipid and lipoprotein metabolism are major contributing factors to the increased CVD risk in NAFLD patients, and many promising NASH therapies in development also improve dyslipidemia in clinical trials.
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Affiliation(s)
- Audrey Deprince
- Univ. Lille, Inserm, CHU Lille, Institut Pasteur de Lille, U1011-EGID, F-59000, Lille, France
| | - Joel T Haas
- Univ. Lille, Inserm, CHU Lille, Institut Pasteur de Lille, U1011-EGID, F-59000, Lille, France.
| | - Bart Staels
- Univ. Lille, Inserm, CHU Lille, Institut Pasteur de Lille, U1011-EGID, F-59000, Lille, France.
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15
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Cortés-Rojo C, Vargas-Vargas MA, Olmos-Orizaba BE, Rodríguez-Orozco AR, Calderón-Cortés E. Interplay between NADH oxidation by complex I, glutathione redox state and sirtuin-3, and its role in the development of insulin resistance. Biochim Biophys Acta Mol Basis Dis 2020; 1866:165801. [PMID: 32305451 DOI: 10.1016/j.bbadis.2020.165801] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2019] [Revised: 03/16/2020] [Accepted: 04/09/2020] [Indexed: 12/13/2022]
Abstract
Metabolic diseases are characterized by high NADH/NAD+ ratios due to excessive electron supply, causing defective mitochondrial function and impaired sirtuin-3 (SIRT-3) activity, the latter driving to oxidative stress and altered fatty acid β-oxidation. NADH is oxidized by the complex I in the electron transport chain, thereby factors inhibiting complex I like acetylation, cardiolipin peroxidation, and glutathionylation by low GSH/GSSG ratios affects SIRT3 function by increasing the NADH/NAD+ ratio. In this review, we summarized the evidence supporting a role of the above events in the development of insulin resistance, which is relevant in the pathogenesis of obesity and diabetes. We propose that maintenance of proper NADH/NAD+ and GSH/GSSG ratios are central to ameliorate insulin resistance, as alterations in these redox couples lead to complex I dysfunction, disruption of SIRT-3 activity, ROS production and impaired β-oxidation, the latter two being key effectors of insulin resistance.
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Affiliation(s)
- Christian Cortés-Rojo
- Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Morelia, Mich 58030, México.
| | - Manuel Alejandro Vargas-Vargas
- Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Morelia, Mich 58030, México
| | - Berenice Eridani Olmos-Orizaba
- Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Morelia, Mich 58030, México
| | - Alain Raimundo Rodríguez-Orozco
- Facultad de Ciencias Médicas y Biológicas "Dr. Ignacio Chávez", Universidad Michoacana de San Nicolás de Hidalgo, Morelia, Mich 58020, México
| | - Elizabeth Calderón-Cortés
- Facultad de Enfermería, Universidad Michoacana de San Nicolás de Hidalgo, Morelia, Mich 58260, México
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16
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Yan T, Yan N, Wang P, Xia Y, Hao H, Wang G, Gonzalez FJ. Herbal drug discovery for the treatment of nonalcoholic fatty liver disease. Acta Pharm Sin B 2020; 10:3-18. [PMID: 31993304 PMCID: PMC6977016 DOI: 10.1016/j.apsb.2019.11.017] [Citation(s) in RCA: 123] [Impact Index Per Article: 30.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Revised: 09/23/2019] [Accepted: 10/31/2019] [Indexed: 12/11/2022] Open
Abstract
Few medications are available for meeting the increasing disease burden of nonalcoholic fatty liver disease (NAFLD) and its progressive stage, nonalcoholic steatohepatitis (NASH). Traditional herbal medicines (THM) have been used for centuries to treat indigenous people with various symptoms but without clarified modern-defined disease types and mechanisms. In modern times, NAFLD was defined as a common chronic disease leading to more studies to understand NAFLD/NASH pathology and progression. THM have garnered increased attention for providing therapeutic candidates for treating NAFLD. In this review, a new model called “multiple organs-multiple hits” is proposed to explain mechanisms of NASH progression. Against this proposed model, the effects and mechanisms of the frequently-studied THM-yielded single anti-NAFLD drug candidates and multiple herb medicines are reviewed, among which silymarin and berberine are already under U.S. FDA-sanctioned phase 4 clinical studies. Furthermore, experimental designs for anti-NAFLD drug discovery from THM in treating NAFLD are discussed. The opportunities and challenges of reverse pharmacology and reverse pharmacokinetic concepts-guided strategies for THM modernization and its global recognition to treat NAFLD are highlighted. Increasing mechanistic evidence is being generated to support the beneficial role of THM in treating NAFLD and anti-NAFLD drug discovery.
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Affiliation(s)
- Tingting Yan
- Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
- Corresponding authors.
| | - Nana Yan
- State Key Laboratory of Natural Medicines, Key Laboratory of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, Nanjing 210009, China
| | - Ping Wang
- Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
- Institute of Interdisciplinary Integrative Medicine Research, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China
| | - Yangliu Xia
- Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
- School of Life Science and Medicine, Dalian University of Technology, Panjin 124221, China
| | - Haiping Hao
- State Key Laboratory of Natural Medicines, Key Laboratory of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, Nanjing 210009, China
| | - Guangji Wang
- State Key Laboratory of Natural Medicines, Key Laboratory of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, Nanjing 210009, China
| | - Frank J. Gonzalez
- Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
- Corresponding authors.
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17
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Lytle KA, Bush NC, Triay JM, Kellogg TA, Kendrick ML, Swain JM, Gathaiya NW, Hames KC, Jensen MD. Hepatic Fatty Acid Balance and Hepatic Fat Content in Humans With Severe Obesity. J Clin Endocrinol Metab 2019; 104:6171-6181. [PMID: 31408176 PMCID: PMC6821207 DOI: 10.1210/jc.2019-00875] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Accepted: 08/07/2019] [Indexed: 12/29/2022]
Abstract
OBJECTIVE Nonalcoholic fatty liver disease can lead to hepatic inflammation/damage. Understanding the physiological mechanisms that contribute to excess hepatic lipid accumulation may help identify effective treatments. DESIGN We recruited 25 nondiabetic patients with severe obesity scheduled for bariatric surgery. To evaluate liver export of triglyceride fatty acids, we measured very-low-density lipoprotein (VLDL)-triglyceride secretion rates the day prior to surgery using an infusion of autologous [1-14C]triolein-labeled VLDL particles. Ketone body response to fasting and intrahepatic long-chain acylcarnitine concentrations were used as indices of hepatic fatty acid oxidation. We measured intraoperative hepatic uptake rates of plasma free fatty acids using a continuous infusion of [U-13C]palmitate, combined with a bolus dose of [9,10-3H]palmitate and carefully timed liver biopsies. Total intrahepatic lipids were measured in liver biopsy samples to determine fatty liver status. The hepatic concentrations and enrichment from [U-13C]palmitate in diacylglycerols, sphingolipids, and acyl-carnitines were measured using liquid chromatography/tandem mass spectrometry. RESULTS Among study participants with fatty liver disease, intrahepatic lipid was negatively correlated with VLDL-triglyceride secretion rates (r = -0.92, P = 0.01) but unrelated to hepatic free fatty acid uptake or indices of hepatic fatty acid oxidation. VLDL-triglyceride secretion rates were positively correlated with hepatic concentrations of saturated diacylglycerol (r = 0.46, P = 0.02) and sphingosine-1-phosphate (r = 0.44, P = 0.03). CONCLUSION We conclude that in nondiabetic humans with severe obesity, excess intrahepatic lipid is associated with limited export of triglyceride in VLDL particles rather than increased uptake of systemic free fatty acids.
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Affiliation(s)
- Kelli A Lytle
- Endocrine Research Unit, Mayo Clinic, Rochester, Minnesota
| | - Nikki C Bush
- Endocrine Research Unit, Mayo Clinic, Rochester, Minnesota
| | | | - Todd A Kellogg
- Department of Surgery, Mayo Clinic, Rochester, Minnesota
| | | | - James M Swain
- Department of Surgery, Mayo Clinic, Rochester, Minnesota
| | | | | | - Michael D Jensen
- Endocrine Research Unit, Mayo Clinic, Rochester, Minnesota
- Correspondence: Michael D. Jensen, MD, Endocrine Research Unit, 5-194 Joseph, Mayo Clinic, 200 First Street SW, Rochester, Minnesota 55905. E-mail:
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18
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Watt MJ, Miotto PM, De Nardo W, Montgomery MK. The Liver as an Endocrine Organ-Linking NAFLD and Insulin Resistance. Endocr Rev 2019; 40:1367-1393. [PMID: 31098621 DOI: 10.1210/er.2019-00034] [Citation(s) in RCA: 311] [Impact Index Per Article: 62.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Accepted: 04/04/2019] [Indexed: 02/06/2023]
Abstract
The liver is a dynamic organ that plays critical roles in many physiological processes, including the regulation of systemic glucose and lipid metabolism. Dysfunctional hepatic lipid metabolism is a cause of nonalcoholic fatty liver disease (NAFLD), the most common chronic liver disorder worldwide, and is closely associated with insulin resistance and type 2 diabetes. Through the use of advanced mass spectrometry "omics" approaches and detailed experimentation in cells, mice, and humans, we now understand that the liver secretes a wide array of proteins, metabolites, and noncoding RNAs (miRNAs) and that many of these secreted factors exert powerful effects on metabolic processes both in the liver and in peripheral tissues. In this review, we summarize the rapidly evolving field of "hepatokine" biology with a particular focus on delineating previously unappreciated communication between the liver and other tissues in the body. We describe the NAFLD-induced changes in secretion of liver proteins, lipids, other metabolites, and miRNAs, and how these molecules alter metabolism in liver, muscle, adipose tissue, and pancreas to induce insulin resistance. We also synthesize the limited information that indicates that extracellular vesicles, and in particular exosomes, may be an important mechanism for intertissue communication in normal physiology and in promoting metabolic dysregulation in NAFLD.
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Affiliation(s)
- Matthew J Watt
- Department of Physiology, University of Melbourne, Melbourne, Victoria, Australia
| | - Paula M Miotto
- Department of Physiology, University of Melbourne, Melbourne, Victoria, Australia
| | - William De Nardo
- Department of Physiology, University of Melbourne, Melbourne, Victoria, Australia
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Santoleri D, Titchenell PM. Resolving the Paradox of Hepatic Insulin Resistance. Cell Mol Gastroenterol Hepatol 2018; 7:447-456. [PMID: 30739869 PMCID: PMC6369222 DOI: 10.1016/j.jcmgh.2018.10.016] [Citation(s) in RCA: 141] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Revised: 10/30/2018] [Accepted: 10/30/2018] [Indexed: 12/12/2022]
Abstract
Insulin resistance is associated with numerous metabolic disorders, such as obesity and type II diabetes, that currently plague our society. Although insulin normally promotes anabolic metabolism in the liver by increasing glucose consumption and lipid synthesis, insulin-resistant individuals fail to inhibit hepatic glucose production and paradoxically have increased liver lipid synthesis, leading to hyperglycemia and hypertriglyceridemia. Here, we detail the intrahepatic and extrahepatic pathways mediating insulin's control of glucose and lipid metabolism. We propose that the interplay between both of these pathways controls insulin signaling and that mis-regulation between the 2 results in the paradoxic effects seen in the insulin-resistant liver instead of the commonly proposed deficiencies in particular branches of only the direct hepatic pathway.
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Affiliation(s)
- Dominic Santoleri
- Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Paul M. Titchenell
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania,Institute for Diabetes, Obesity, and Metabolism, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania,Correspondence Address correspondence to: Paul M. Titchenell, PhD, Perelman School of Medicine, University of Pennsylvania, 3400 Civic Center Boulevard, Philadelphia, Pennsylvania 19104. fax: (215) 898-5408.
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20
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Effect of Dachaihu decoction on non-alcoholic fatty liver disease model rats induced by a high-fat high-sugar diet. JOURNAL OF TRADITIONAL CHINESE MEDICAL SCIENCES 2018. [DOI: 10.1016/j.jtcms.2018.10.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
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21
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Poulsen MK, Nellemann B, Bibby BM, Stødkilde-Jørgensen H, Pedersen SB, Grønbaek H, Nielsen S. No effect of resveratrol on VLDL-TG kinetics and insulin sensitivity in obese men with nonalcoholic fatty liver disease. Diabetes Obes Metab 2018; 20:2504-2509. [PMID: 29885082 DOI: 10.1111/dom.13409] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2018] [Revised: 06/02/2018] [Accepted: 06/05/2018] [Indexed: 12/19/2022]
Abstract
The present study (NCT01446276, ClinicalTrials.gov) assessed long-term effects of high-dose Resveratrol (RSV) on basal and insulin-mediated very low-density lipoprotein triglyceride (VLDL-TG), palmitate and glucose kinetics, and liver fat content in men with nonalcoholic fatty liver disease (NAFLD). Participants (n = 16) were non-diabetic, upper-body obese (BMI > 28 kg/m2 , WHR > 0.9) men with NAFLD who were randomized (1:1) in a double-blinded, placebo-controlled clinical trial to either RSV or placebo (500 mg 3 times daily) for 6 months. Magnetic resonance (MR) spectroscopy, dual-X-ray absorptiometry and MR imaging assessed liver fat content and body composition, respectively. 14 C-labeled VLDL-TG and 3 H-labeled glucose and palmitate tracers, in combination with indirect calorimetry and breath samples, were used to assess kinetics and substrate oxidations during basal and hyperinsulinaemic euglycaemic clamp conditions. RSV did not improve either basal or insulin-mediated VLDL-TG secretion, oxidation or clearance rates, nor did it affect palmitate or glucose turnover. Likewise, no changes in body composition or liver fat content occurred following RSV compared with placebo treatment. Therefore, RSV cannot be recommended for treatment of metabolic abnormalities in NAFLD.
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Affiliation(s)
- Marianne K Poulsen
- Department of Endocrinology and Internal Medicine, Aarhus University Hospital, Aarhus, Denmark
| | - Birgitte Nellemann
- Department of Endocrinology and Internal Medicine, Aarhus University Hospital, Aarhus, Denmark
| | - Bo Martin Bibby
- Department of Public Health, Aarhus University, Aarhus, Denmark
| | | | - Steen B Pedersen
- Department of Endocrinology and Internal Medicine, Aarhus University Hospital, Aarhus, Denmark
| | - Henning Grønbaek
- Department of Hepatology and Gastroenterology, Aarhus University Hospital, Aarhus, Denmark
| | - Søren Nielsen
- Department of Endocrinology and Internal Medicine, Aarhus University Hospital, Aarhus, Denmark
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Abstract
PURPOSE OF REVIEW Abdominal obesity is associated with a number of important metabolic abnormalities including liver steatosis, insulin resistance and an atherogenic lipoprotein profile (termed dyslipidemia). The purpose of this review is to highlight recent progress in understanding the pathogenesis of this dyslipidemia. RECENT FINDINGS Recent results from kinetic studies using stable isotopes indicate that the hypertriglyceridemia associated with abdominal obesity stems from dual mechanisms: (1) enhanced secretion of triglyceride-rich lipoproteins and (2) impaired clearance of these lipoproteins. The over-secretion of large triglyceride-rich VLDLs from the liver is linked to hepatic steatosis and increased visceral adiposity. The impaired clearance of triglyceride-rich lipoproteins is linked to increased levels of apolipoprotein C-III, a key regulator of triglyceride metabolism. SUMMARY Elucidation of the pathogenesis of the atherogenic dyslipidemia in abdominal obesity combined with the development of novel treatments based on apolipoprotein C-III may in the future lead to better prevention, diagnosis and treatment of the atherogenic dyslipidemia in abdominal obesity.
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Affiliation(s)
- Elias Björnson
- aDepartment of Molecular and Clinical Medicine, University of Gothenburg and Sahlgrenska University Hospital, Gothenburg, Sweden bResearch Programs Unit, Diabetes and Obesity, University of Helsinki and Heart and Lung Center, Helsinki University Hospital, Helsinki, Finland
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Paglialunga S, Dehn CA. Clinical assessment of hepatic de novo lipogenesis in non-alcoholic fatty liver disease. Lipids Health Dis 2016; 15:159. [PMID: 27640119 PMCID: PMC5027077 DOI: 10.1186/s12944-016-0321-5] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Accepted: 08/30/2016] [Indexed: 02/07/2023] Open
Abstract
Non-alcoholic fatty liver disease (NAFLD) is heralded as the next big global epidemic. Hepatic de novo lipogenesis (DNL), the synthesis of new fatty acids from non-lipid sources, is thought to play a pivotal role in the development of NAFLD. While there is currently no NAFLD-specific therapeutic agent available, pharmaceutical drugs aimed at reducing hepatic fat accretion may prove to be a powerful ally in the treatment and management of this disease. With a focus on NAFLD, the present review summarizes current techniques examining DNL from a clinical perspective, and describes the merits and limitations of three commonly used assays; stable-label isotope tracer studies, fatty acid indexes and indirect calorimetry as non-invasive measures of hepatic DNL. Finally, the application of DNL assessments in the pharmacological and nutraceutical treatment of NAFLD/NASH is summarized. In a clinical research setting, measures of DNL are an important marker in the development of anti-NAFLD treatments.
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Affiliation(s)
- Sabina Paglialunga
- Global Clinical Research, Celerion, 2420 West Baseline Road, Tempe, AZ, 85283, USA.
| | - Clayton A Dehn
- Global Clinical Research, Celerion, 2420 West Baseline Road, Tempe, AZ, 85283, USA.,Current affiliation: Umbrella Corporation, San Antonio, TX, USA
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