Browsing by Subject "FATTY LIVER"

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  • Ruhanen, Hanna; Haridas, P. A. Nidhina; Jauhiainen, Matti; Olkkonen, Vesa M. (2020)
    Angiopoietin like protein 3 (ANGPTL3) is best known for its function as an inhibitor of lipoprotein and endothelial lipases. Due to the capacity of genetic or pharmacologic ANGPTL3 suppression to markedly reduce circulating lipoproteins, and the documented cardioprotection upon such suppression, ANGPTL3 has become an emerging therapy target for which both antibody and antisense oligonucleotide (ASO) therapeutics are being clinically tested. While the antibody is relatively selective for circulating ANGPTL3, the ASO also depletes the intra-hepatocellular protein, and there is emerging evidence for cell-autonomous functions of ANGPTL3 in the liver. These include regulation of hepatocyte glucose and fatty acid uptake, insulin sensitivity, LDL/VLDL remnant uptake, VLDL assembly/secretion, polyunsaturated fatty acid (PUFA) and PUFA-derived lipid mediator content, and gene expression. In this review we elaborate on (i) why ANGPTL3 is considered one of the most promising new cardiometabolic therapy targets, and (ii) the present evidences for its intra-hepatocellular or cell-autonomous functions.
  • Harjumäki, Riina; Pridgeon, Chris S.; Ingelman-Sundberg, Magnus (2021)
    CYP2E1 is one of the fifty-seven cytochrome P450 genes in the human genome and is highly conserved. CYP2E1 is a unique P450 enzyme because its heme iron is constitutively in the high spin state, allowing direct reduction of, e.g., dioxygen, causing the formation of a variety of reactive oxygen species and reduction of xenobiotics to toxic products. The CYP2E1 enzyme has been the focus of scientific interest due to (i) its important endogenous function in liver homeostasis, (ii) its ability to activate procarcinogens and to convert certain drugs, e.g., paracetamol and anesthetics, to cytotoxic end products, (iii) its unique ability to effectively reduce dioxygen to radical species causing liver injury, (iv) its capability to reduce compounds, often generating radical intermediates of direct toxic or indirect immunotoxic properties and (v) its contribution to the development of alcoholic liver disease, steatosis and NASH. In this overview, we present the discovery of the enzyme and studies in humans, 3D liver systems and genetically modified mice to disclose its function and clinical relevance. Induction of the CYP2E1 enzyme either by alcohol or high-fat diet leads to increased severity of liver pathology and likelihood to develop ALD and NASH, with subsequent influence on the occurrence of hepatocellular cancer. Thus, fat-dependent induction of the enzyme might provide a link between steatosis and fibrosis in the liver. We conclude that CYP2E1 has many important physiological functions and is a key enzyme for hepatic carcinogenesis, drug toxicity and liver disease.
  • Åberg, Fredrik; Färkkilä, Martti; Männistö, Ville (2020)
    Coexistence of alcohol use and metabolic risk-the 2 commonest population risk factors for nonviral chronic liver disease-is a growing concern. Clinical evidence and mechanistic evidence point to considerable supraadditive interaction effects for the development and progression of chronic liver disease between hazardous alcohol use and metabolic abnormalities including obesity, diabetes, and the metabolic syndrome (MetS). Intermittent binge drinking once monthly or more often seems to be associated with progression of liver disease even when average alcohol intake is within the currently allowed limits for a diagnosis of nonalcoholic fatty liver disease (NAFLD), and supraadditive interaction between binge drinking and the MetS has been reported. There are contradictory findings regarding the association between low alcohol use and liver steatosis, but, clearly, the mechanisms of alcoholic hepatotoxicity extend beyond simple fat accumulation. The presence of liver steatosis seems to amplify alcoholic hepatotoxicity. Recent longitudinal studies of NAFLD subjects report low alcohol use associated with both increased fibrosis progression and an elevated risk for liver cancer and severe liver disease. There is no clear safe limit of alcohol intake in the presence of NAFLD or metabolic risk. The interaction effects between alcohol and metabolic dysfunction merit increased attention in public health policy, individual counseling, and risk stratification. Based on current evidence, a strict dichotomization of liver disease into either pure alcoholic or nonalcoholic may be inappropriate.
  • Pajunen, Pia; Kotronen, Anna; Korpi-Hyovalti, Eeva; Keinanen-Kiukaanniemi, Sirkka; Oksa, Heikki; Niskanen, Leo; Saaristo, Timo; Saltevo, Juha T.; Sundvall, Jouko; Vanhala, Mauno; Uusitupa, Matti; Peltonen, Markku (2011)
  • Qin, Nanbing; Kokkonen, Tuomo Juhani; Salin, Siru; Seppänen-Laakso, Tuulikki; Taponen, Juhani Olavi; Vanhatalo, Aila Orvokki; Elo, Kari Tapani (2018)
    The liver of dairy cow naturally undergoes metabolic adaptation during the periparturient period in response to the increasing demand for nutrients. The hepatic adaptation is affected by prepartal energy intake level and is potentially associated with inflammatory responses. lb study the changes in the liver function during the periparturient period, 16 cows (body condition score = 3.7 +/- 0.3, mean +/- standard deviation; parity = second through fourth) were allocated to a grass silage-based controlled-energy diet (104 MJ/d) or a high-energy diet (135 MJ/d) during the last 6 wk before the predicted parturition. Liver samples were collected by biopsy at 8 d before the predicted parturition (-8 d) and at 1 and 9 d after the actual parturition (1 and 9 d). The lipidomic profile of liver samples collected at -8 and 9 d was analyzed using ultra performance liquid chromatography-mass spectrometry-based lipidomics. Liver samples from all the time points were subjected to microarray analysis and the subsequent pathway analysis with Ingenuity Pathway Analysis software (Ingenuity Systems, Mountain View, CA). Prepartal energy intake level affected hepatic gene expression and lipidomic profiles prepartum, whereas little or no effect was observed postpartum. At. 8 d, hepatic lipogenesis was promoted by prepartal high-energy feeding through the activation of X receptor/retinoid X receptor pathway and through increased transcription of thyroid hormone-responsive (THRSP). Hepatic inflammatory and acute phase responses at -8 d were suppressed (z-score = -2.236) by prepartal high-energy feeding through the increase in the mRNA abundance of suppressor of cytokine signaling 3 (SOCS9) and the decrease in the mRNA abundance of interleukin 1 (IL1), nuclear factor kappa B 1 (NFKB1), apolipoprotein A1 (APOA1), serum amyloid A3 (SAA3), haptoglobin (HP), lipopolysaccharide-binding protein (LBP), and inter-alpha-trypsin inhibitor heavy chain 3 (ITIH3). Moreover, prepartal high-energy feeding elevated hepatic concentrations of C18- (7%), C20- (17%), C21(26%), C23-sphingomyelins (26%), and total saturated sphingomyelin (21%). In addition, cows in both groups displayed increased lipogenesis at the gene expression level after parturition and alterations in the concentration of various sphingolipids between the first and last samplings. In conclusion, prepartal high-energy feeding promoted lipogenesis and suppressed inflammatory and acute phase responses in the liver before parturition, whereas only minor effects were observed after parturition.
  • Qin, Nanbing; Kokkonen, Tuomo; Salin, Siru; Seppänen-Laakso, Tuulikki; Taponen, Juhani; Vanhatalo, Aila; Elo, Kari (2017)
    Introduction Physiological adaptations in the energy metabolism of dairy cows during the periparturient period are partly mediated by insulin resistance (IR), which may subsequently induce metabolic disorders postpartum. The molecular mechanisms underlying IR in dairy cows are largely unknown. Objective This study aimed to find a novel insight into the molecular mechanisms underlying IR in dairy cows during the periparturient period by analyzing the effects of prepartal overfeeding on the lipidomic profiles in the liver and adipose tissue (AT). Methods Sixteen cows were allocated to controlled-energy and high-energy feeding groups. Lipidomic profiling was conducted on liver and adipose tissue samples collected at 8 days prior to the predicted parturition, and 1 day (only AT) and 9 days after the actual parturition. Results Five ceramides (Cers) were identified to be significantly increased by prepartal overfeeding in AT in the analysis of the variance between groups within time points. Principal component-linear discriminant analysis showed that lipidomic profiles between the feeding groups were mainly characterized by phosphatidylcholines (PC), phosphatidylethanolamines (PE), lysophophosphatidylcholines (LysoPC), and lysophosphatidylethanolamines (LysoPE) in the liver, and by Cer, PE, and phosphatidylinositols (PI) in AT. Lipid class levels indicated that prepartal overfeeding elevated the concentration of PE, PI, LysoPC, LysoPE, and sphingomyelin in the liver, and increased the concentration of Cer in AT during the periparturient period. Conclusion Prepartal overfeeding significantly altered the concentrations of various sphingolipids, phospholipids, and lysophospholipids in the liver and AT of dairy cows during the periparturient period.
  • EFSA Panel Dietetic Prod Nutr; Heinonen, Marina (2017)
    Following a request from the European Commission, the EFSA Panelon Dietetic Products, Nutrition and Allergies (NDA) was asked to deliver an opinion on betaine as a novel food (NF) pursuant to Regulation (EC) No 258/97. The information provided on the composition, the specifications, the batch-to-batch variability, stability and production process of the NF is sufficient and does not raise concerns about the safety of the NF. The NF is proposed to be used in foods intended to meet additional requirements for intense muscular effort with a maximum intake of 2.5 g/day of betaine for sports people above 10 years of age. Based on the lowest BMDL05, which was derived from a chronic toxicity study in rats in which a dose-related increase in platelet counts was observed, and the anticipated daily intake of the NF in the target population, the Margins of Exposure are 3.6 and 5, which are generally regarded as not sufficient. However, the total exposure to betaine from the diet (about 830 mg/day) is not known to be associated with adverse effects. Moreover, no adverse effects on platelet counts were noted in human intervention studies with exposure levels of 4 g/day of betaine for up to 6 months. A significant increase in total and low-density lipoprotein (LDL)-cholesterol concentrations was noted at intakes of 4 g/day of betaine in overweight subjects with metabolic syndrome but not in healthy subjects, nor at intakes of 3 g/day. Thus, considering 4 g/day of betaine as a reference point and applying an uncertainty factor of 10 to account for interindividual variability, an amount of 400 mg/day of betaine in addition to the background exposure is considered as safe. The Panelconsiders that the NF is safe to be used at maximum intake of 400 mg/day in the target population. (C) 2017 European Food Safety Authority. EFSA Journal published by John Wiley and Sons Ltd on behalf of European Food Safety Authority.