101
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Sun SZ, Empie MW. Fructose metabolism in humans - what isotopic tracer studies tell us. Nutr Metab (Lond) 2012; 9:89. [PMID: 23031075 PMCID: PMC3533803 DOI: 10.1186/1743-7075-9-89] [Citation(s) in RCA: 186] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2012] [Accepted: 09/24/2012] [Indexed: 12/17/2022] Open
Abstract
Fructose consumption and its implications on public health are currently under study. This work reviewed the metabolic fate of dietary fructose based on isotope tracer studies in humans. The mean oxidation rate of dietary fructose was 45.0% ± 10.7 (mean ± SD) in non-exercising subjects within 3–6 hours and 45.8% ± 7.3 in exercising subjects within 2–3 hours. When fructose was ingested together with glucose, the mean oxidation rate of the mixed sugars increased to 66.0% ± 8.2 in exercising subjects. The mean conversion rate from fructose to glucose was 41% ± 10.5 (mean ± SD) in 3–6 hours after ingestion. The conversion amount from fructose to glycogen remains to be further clarified. A small percentage of ingested fructose (<1%) appears to be directly converted to plasma TG. However, hyperlipidemic effects of larger amounts of fructose consumption are observed in studies using infused labeled acetate to quantify longer term de novo lipogenesis. While the mechanisms for the hyperlipidemic effect remain controversial, energy source shifting and lipid sparing may play a role in the effect, in addition to de novo lipogenesis. Finally, approximately a quarter of ingested fructose can be converted into lactate within a few of hours. The reviewed data provides a profile of how dietary fructose is utilized in humans.
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Affiliation(s)
- Sam Z Sun
- Compliance, Archer Daniels Midland Company, 1001 North Brush College Road, Decatur, IL, 62521, USA.
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102
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Watanabe M, Fuda H, Jin S, Sakurai T, Hui SP, Takeda S, Watanabe T, Koike T, Chiba H. A phenolic antioxidant from the Pacific oyster (Crassostrea gigas) inhibits oxidation of cultured human hepatocytes mediated by diphenyl-1-pyrenylphosphine. Food Chem 2012; 134:2086-9. [DOI: 10.1016/j.foodchem.2012.04.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2011] [Revised: 02/22/2012] [Accepted: 04/02/2012] [Indexed: 01/30/2023]
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103
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Valdecantos MP, Pérez-Matute P, González-Muniesa P, Prieto-Hontoria PL, Moreno-Aliaga MJ, Martínez JA. Lipoic acid improves mitochondrial function in nonalcoholic steatosis through the stimulation of sirtuin 1 and sirtuin 3. Obesity (Silver Spring) 2012; 20:1974-83. [PMID: 22327056 DOI: 10.1038/oby.2012.32] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Nonalcoholic steatosis is an important hepatic complication of obesity linked to mitochondrial dysfunction and oxidative stress. Lipoic acid (LA) has been reported to have beneficial effects on mitochondrial function and to attenuate oxidative stress. The sirtuin (SIRT) family has been demonstrated to play an important role in the regulation of mitochondrial function and in the activation of antioxidant defenses. In this study, we analyzed the potential protective effect of LA supplementation, via the modulation of mitochondrial defenses through the SIRT pathway, against oxidative stress associated with high-fat feeding. Wistar rats were fed a standard diet (control group (C), n = 10), a high-fat diet (obese group (OB), n = 10) and a high-fat diet supplemented with LA (OLIP, n = 10). A group pair-fed to the latter group (pair-fed OLIP group (PFO), n = 6) was also included. LA prevented hepatic triglyceride (TG) accumulation (-68.2%) and liver oxidative damage (P < 0.01) through the inhibition of hydroperoxide (H(2)O(2)) production (P < 0.001) and the stimulation of mitochondrial antioxidant defenses. LA treatment upregulated manganese superoxide dismutase (SOD2) (60.6%) and glutathione peroxidase (GPx) (100.2%) activities, and increased the reduced glutathione (GSH): oxidized glutathione (GSSG) ratio and UCP2 mRNA levels (P < 0.001-P < 0.01). Moreover, this molecule reduced oxidative damage in mitochondrial DNA (mtDNA) and increased mitochondrial copy number (P < 0.001- P < 0.01). LA treatment decreased the acetylation levels of Forkhead transcription factor 3a (Foxo3a) and PGC1β (P < 0.001- P < 0.01) through the stimulation of SIRT3 and SIRT1 (P < 0.001). In summary, our results demonstrate that the beneficial effects of LA supplementation on hepatic steatosis could be mediated by its ability to restore the oxidative balance by increasing antioxidant defenses through the deacetylation of Foxo3a and PGC1β by SIRT1 and SIRT3.
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Affiliation(s)
- M Pilar Valdecantos
- Department of Nutrition, Food Science, Physiology and Toxicology, University of Navarra, Pamplona, Spain
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104
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Musso G, Cassader M, De Michieli F, Rosina F, Orlandi F, Gambino R. Nonalcoholic steatohepatitis versus steatosis: adipose tissue insulin resistance and dysfunctional response to fat ingestion predict liver injury and altered glucose and lipoprotein metabolism. Hepatology 2012; 56:933-42. [PMID: 22684858 DOI: 10.1002/hep.25739] [Citation(s) in RCA: 99] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/01/2012] [Accepted: 03/19/2012] [Indexed: 02/06/2023]
Abstract
UNLABELLED Nonalcoholic fatty liver disease (NAFLD) ranges from simple steatosis (SS) to nonalcoholic steatohepatitis (NASH). Though liver-related risk seems confined to NASH, it is currently unclear whether NASH has a higher risk of cardiovascular disease (CVD) and diabetes than SS as a result of the coexistence of obesity and other cardiometabolic confounders. Adipose tissue is an emerging modulator of liver disease in NAFLD and of cardiometabolic disease in the general population. We evaluated in SS and NASH (1) glucose homeostasis and cardiovascular risk profile and (2) the effect of adipose tissue dysfunction, assessed in fasting conditions and postprandially, on liver injury, glucose and lipoprotein metabolism, and markers of early atherosclerosis. Forty nonobese, nondiabetic, normolipidemic biopsy-proven NAFLD patients (20 with SS and 20 with NASH) and 40 healthy subjects, matched for overall/abdominal adiposity and metabolic syndrome, underwent an oral fat load test, with measurement of plasma triglyceride-rich lipoproteins, oxidized low-density lipoproteins, adipokines, and cytokeratin-18 fragments, and an oral glucose tolerance test with minimal model analysis to yield glucose homeostasis parameters. Circulating endothelial adhesion molecules were measured, and adipose tissue insulin resistance (adipose IR) index and visceral adiposity index were calculated. Despite similar fasting values, compared to SS, NASH showed a more atherogenic postprandial lipoprotein profile, an altered adipokine response (i.e., higher resistin increase and an adiponectin fall), and hepatocyte apoptosis activation after fat ingestion. Adipose IR index, endothelial adhesion molecules, and hepatic insulin resistance progressively increased across NAFLD stages. NASH, but not SS, showed an impaired pancreatic β-cell function. On multiple regression analysis, adipose IR index and postprandial adiponectin independently predicted liver histology and altered cardiometabolic parameters. CONCLUSION Adipose tissue dysfunction, including a maladaptive adipokine response to fat ingestion, modulates liver injury and cardiometabolic risk in NAFLD.
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105
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Xu L, Xu C, Yu C, Miao M, Zhang X, Zhu Z, Ding X, Li Y. Association between serum growth hormone levels and nonalcoholic fatty liver disease: a cross-sectional study. PLoS One 2012; 7:e44136. [PMID: 22952901 PMCID: PMC3432067 DOI: 10.1371/journal.pone.0044136] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2012] [Accepted: 07/31/2012] [Indexed: 01/13/2023] Open
Abstract
Growth hormone (GH) is an important regulator of metabolism and body composition. GH deficiency is associated with increased visceral body fat and other features of the metabolic syndrome. Here we performed a cross-sectional study to explore the association of GH levels with nonalcoholic fatty liver disease (NAFLD), which is considered to be the hepatic manifestation of the metabolic syndrome. A total of 1,667 subjects were diagnosed as NAFLD according the diagnostic criteria, and 5,479 subjects were defined as the controls. The subjects with NAFLD had significantly lower levels of serum GH than the controls. Those with low GH levels had a higher prevalence of NAFLD and the metabolic syndrome. A stepwise logistic regression analysis showed that GH levels were significantly associated with the risk factor for NAFLD (OR = 0.651, 95%CI = 0.574–0.738, P<0.001). Our results showed a significant association between lower serum GH levels and NAFLD.
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Affiliation(s)
- Lei Xu
- Department of Gastroenterology, Ningbo No. 1 Hospital, Ningbo, China
- Department of Gastroenterology, the First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China
| | - Chengfu Xu
- Department of Gastroenterology, the First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China
| | - Chaohui Yu
- Department of Gastroenterology, the First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China
| | - Min Miao
- Department of Gastroenterology, Zhenhai Lianhua Hospital, Ningbo, China
| | - Xuequn Zhang
- Department of Gastroenterology, the First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China
| | - Zhongwei Zhu
- Department of Gastroenterology, Zhenhai Lianhua Hospital, Ningbo, China
| | - Xiaoyun Ding
- Department of Gastroenterology, Ningbo No. 1 Hospital, Ningbo, China
| | - Youming Li
- Department of Gastroenterology, the First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China
- * E-mail:
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106
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Affiliation(s)
- Rocco Barazzoni
- Department of Medical, Surgical and Health Sciences, Clinica Medica, University of Trieste, Trieste, Italy.
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107
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Musso G, Cassader M, Rosina F, Gambino R. Impact of current treatments on liver disease, glucose metabolism and cardiovascular risk in non-alcoholic fatty liver disease (NAFLD): a systematic review and meta-analysis of randomised trials. Diabetologia 2012; 55:885-904. [PMID: 22278337 DOI: 10.1007/s00125-011-2446-4] [Citation(s) in RCA: 470] [Impact Index Per Article: 39.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/02/2011] [Accepted: 12/02/2011] [Indexed: 12/13/2022]
Abstract
AIMS/HYPOTHESIS Non-alcoholic fatty liver disease (NAFLD) encompasses a spectrum ranging from simple steatosis to non-alcoholic steatohepatitis (NASH): NAFLD causes an increased risk of cardiovascular disease, diabetes and liver-related complications (the latter confined to NASH). The effect of proposed treatments on liver disease, glucose metabolism and cardiovascular risk in NAFLD is unknown. We reviewed the evidence for the management of liver disease and cardio-metabolic risk in NAFLD. METHODS Publications through November 2011 were systematically reviewed by two authors. Outcomes evaluated though standard methods were: histological/radiological/biochemical features of NAFLD, variables of glucose metabolism and cardiovascular risk factors. Seventy-eight randomised trials were included (38 in NASH, 40 in NAFLD): 41% assessed post-treatment histology, 71% assessed glucose metabolism and 88% assessed cardiovascular risk factors. Lifestyle intervention, thiazolidinediones, metformin and antioxidants were most extensively evaluated. RESULTS Lifestyle-induced weight loss was safe and improved cardio-metabolic risk profile; a weight loss ≥7% improved histological disease activity, but was achieved by <50% patients. Statins and polyunsaturated fatty acids improved steatosis, but their effects on liver histology are unknown. Thiazolidinediones improved histological disease activity, glucose, lipid and inflammatory variables and delayed fibrosis progression. Pioglitazone also improved blood pressure. Weight gain (up to 4.8%) was common. Antioxidants yielded mixed histological results: vitamin E improved histological disease activity when administered for 2 years, but increased insulin resistance and plasma triacylglycerols. CONCLUSIONS/INTERPRETATION Weight loss is safe, and improves liver histology and cardio-metabolic profile. For patients not responding to lifestyle intervention, pioglitazone improves histological disease activity, slows fibrosis progression and extensively ameliorates cardio-metabolic endpoints. Further randomised controlled trials (RCTs) of adequate size and duration will assess long-term safety and efficacy of proposed treatments on clinical outcomes.
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Affiliation(s)
- G Musso
- Gradenigo Hospital, C.so Regina Margherita 8, Turin, Italy.
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108
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Grattagliano I, de Bari O, Bernardo TC, Oliveira PJ, Wang DQH, Portincasa P. Role of mitochondria in nonalcoholic fatty liver disease--from origin to propagation. Clin Biochem 2012; 45:610-8. [PMID: 22484459 DOI: 10.1016/j.clinbiochem.2012.03.024] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2011] [Revised: 02/02/2012] [Accepted: 03/12/2012] [Indexed: 12/12/2022]
Abstract
OBJECTIVES Mitochondria play a major role in cell energy-generating processes and integrate several signalling pathways to control cellular life and death. DESIGN AND METHODS Several liver diseases are characterized by mitochondrial alterations which are directly or indirectly dependent on the activation of intracellular stress cascades or receptor-mediated pathways. This article examines the role of mitochondrial dysfunction in critical initiating or propagating events in fatty liver infiltration and nonalcoholic fatty liver disease (NAFLD). Genetic variants and the role of drug-induced toxicity have been considered. RESULTS Key alterations of mitochondrial physiology associated with hepatocyte fatty changes are described. The value of novel non-invasive diagnostic methods to detect mitochondrial metabolic alterations is also discussed. CONCLUSIONS Mitochondrial metabolic remodeling is a predominant factor in the appearance and perpetuation of hepatocyte fat accumulation. Non-invasive techniques to identify mitochondrial dysfunction and proper mitochondria protection are two necessary clinical steps for an efficient management of NAFLD.
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Affiliation(s)
- Ignazio Grattagliano
- Department of Interdisciplinary Medicine, Clinica Medica A. Murri, University of Bari Medical School, Bari, Italy.
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109
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Kučera O, Roušar T, Staňková P, Haňáčková L, Lotková H, Podhola M, Cervinková Z. Susceptibility of rat non-alcoholic fatty liver to the acute toxic effect of acetaminophen. J Gastroenterol Hepatol 2012; 27:323-30. [PMID: 21649732 DOI: 10.1111/j.1440-1746.2011.06807.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
BACKGROUND AND AIM Acetaminophen overdose is the most frequent cause of acute liver failure. Non-alcoholic fatty liver disease is the most common chronic condition of the liver. The aim was to assess whether non-alcoholic steatosis sensitizes rat liver to acute toxic effect of acetaminophen. METHODS Male Sprague-Dawley rats were fed a standard diet (ST-1, 10% kcal fat) and high-fat gelled diet (HFGD, 71% kcal fat) for 6 weeks and then acetaminophen was applied in a single dose (1 g/kg body weight). Animals were killed 24, 48 and 72 h after acetaminophen administration. Serum biochemistry, activities of mitochondrial complexes, hepatic malondialdehyde, reduced and oxidized glutathione, triacylglycerol and cholesterol contents, and concentrations of serum and liver cytokines (TNF-α, TGF-β1) were measured and histopathological samples were prepared. RESULTS The degree of liver inflammation and hepatocellular necrosis were significantly higher in HFGD fed animals after acetaminophen administration. Serum markers of liver injury were elevated only in acetaminophen treated HFGD fed animals. Concentration of hepatic reduced glutathione and ratio of reduced/oxidized glutathione were decreased in both ST-1 and HFGD groups at 24 h after acetaminophen application. Mild oxidative stress induced by acetaminophen was confirmed by measurement of malondialdehyde. Liver content of TNF-α was not significantly altered, but hepatic TGF-β1 was elevated in acetaminophen treated HFGD rats. We did not observe acetaminophen-induced changes in activities of respiratory complexes I, II, and IV and activity of caspase-3. CONCLUSION Liver from rats fed HFGD is more susceptible to acute toxic effect of acetaminophen, compared to non-steatotic liver.
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Affiliation(s)
- Otto Kučera
- Department of Physiology, Charles University in Prague, Faculty of Medicine in Hradec Králové and University Hospital Hradec Králové, Hradec Králové, Czech Republic.
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110
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Yimin, Furumaki H, Matsuoka S, Sakurai T, Kohanawa M, Zhao S, Kuge Y, Tamaki N, Chiba H. A novel murine model for non-alcoholic steatohepatitis developed by combination of a high-fat diet and oxidized low-density lipoprotein. J Transl Med 2012; 92:265-81. [PMID: 22064320 DOI: 10.1038/labinvest.2011.159] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Non-alcoholic steatohepatitis (NASH) is the hepatic manifestation of metabolic syndrome that is characterized by steatosis, inflammation, and fibrosis, and may progress to cirrhosis and carcinoma. To investigate its pathogenic processes, we established a novel murine model for NASH by combination of a high-fat diet (HFD) and oxidized low-density lipoprotein (oxLDL). Mice that received HFD for 23 weeks showed hepatic steatosis, slight fibrosis, and a high level of lipid peroxidation compared with a regular diet (RD)-fed mice. Hepatic injury and elevated tumor necrosis factor (TNF)-α mRNA expression were also detected in these mice. Moreover, oxLDL administration to HFD-fed mice during weeks 21-23 not only aggravated hepatic steatosis, fibrosis, and lipid metabolism, but also resulted in intense inflammation, including severe hepatic injury and inflammatory cell infiltration, which are the typical histological features of NASH. Inflammation was accompanied by increased gene expression of TNF-α and interleukin (IL)-6. Additionally, the livers of RD-fed animals treated with oxLDL during weeks 21-23 were characterized by foamy macrophages and inflammatory cell infiltration along with an elevated IL-6 mRNA level. These results suggest that an increased oxidative state, including HFD-induced intracellular lipid peroxidation and its extracellular source from oxLDL, is the actual trigger for hepatic inflammation in which liver injury is mediated by TNF-α and inflammatory cell accumulation is dependent on IL-6. HFD and oxLDL also induced insulin resistance in mice; additionally, oxLDL downregulated insulin secretion. In this model, CD36 overexpression was observed in the hepatocytes of HFD-fed mice and those treated with HFD and oxLDL, and in the hepatic macrophages of RD-fed mice immediately after oxLDL treatment. In vitro experiments indicated a rapid and transient elevation of CD36 on macrophage plasma membrane in response to oxLDL. Our findings demonstrate that CD36 expressed on hepatocytes and hepatic macrophages mediates the pathophysiology of NASH.
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Affiliation(s)
- Yimin
- Department of Advanced Medicine, Graduate School of Medicine, Hokkaido University, Sapporo, Japan
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111
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Valdecantos MP, Pérez-Matute P, Prieto-Hontoria PL, Sánchez-Campayo E, Moreno-Aliaga MJ, Martínez JA. Erythrocyte antioxidant defenses as a potential biomarker of liver mitochondrial status in different oxidative conditions. Biomarkers 2011; 16:670-8. [PMID: 21999619 DOI: 10.3109/1354750x.2011.625504] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The need for minimally invasive biomarkers to predict the progression of non-alcoholic fatty liver disease to non-alcoholic steatohepatitis is a priority. Oxidative stress and mitochondrial dysfunction contribute in this physiopathological process. The aim of this study was to analyze the potential role of erythrocytes as surrogate biomarkers of hepatic mitochondrial oxidative status in an animal model under different dietary oxidative conditions. Interestingly, we found that erythrocyte antioxidant status correlated with triglyceride content (p < 0.05-p < 0.001), thiobarbituric acid reactive species levels (p < 0.001) and with liver mitochondrial antioxidant levels (p < 0.001). These data suggest that erythrocyte antioxidant defenses could be used as sensitive and minimally invasive biomarkers of mitochondrial status in diverse oxidative conditions.
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Affiliation(s)
- M Pilar Valdecantos
- Department of Nutrition, Food Science, Physiology and Toxicology University of Navarra, Pamplona, Spain
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112
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Musso G, Cassader M, De Michieli F, Saba F, Bo S, Gambino R. Effect of lectin-like oxidized LDL receptor-1 polymorphism on liver disease, glucose homeostasis, and postprandial lipoprotein metabolism in nonalcoholic steatohepatitis. Am J Clin Nutr 2011; 94:1033-42. [PMID: 21865331 DOI: 10.3945/ajcn.111.015610] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
BACKGROUND Nonalcoholic steatohepatitis (NASH) affects 3-5% of the general adult population and predisposes to cirrhosis, cardiovascular disease (CVD), and diabetes through unclear mechanisms. Lectin-like oxidized LDL receptor-1 (LOX-1) has been connected to CVD risk in the general population and to insulin resistance and hepatic fibrogenesis in experimental models. OBJECTIVE The objective was to assess the effect of the common functional LOX-1 IVS4-14 A→G polymorphism on liver disease, adipokines, oxidative stress, lipoprotein metabolism, and glucose homeostasis in NASH. DESIGN Forty nonobese, nondiabetic, normolipidemic biopsy-proven NASH patients and 40 age-, sex-, BMI-, and LOX-1 IVS4-14 A→G polymorphism--matched healthy control subjects underwent an oral-fat-load test (OFT), with measurement of plasma triglyceride-rich lipoprotein (TRLP) subfractions, oxidized LDL, total antioxidant status (TAS), adipokines (resistin and adiponectin), and cytokeratin-18 fragments (marker of hepatocyte apoptosis). The subjects also underwent an oral-glucose-tolerance test (OGTT), with minimal model analysis to yield variables of glucose homeostasis. RESULTS The LOX-1 polymorphism was independently associated with liver histology (G allele carriers had more severe liver disease); during the OFT, the G allele was associated with small TRLP accumulation, lower TAS, adipokine imbalance (higher resistin and lower adiponectin), and increased cytokeratin-18 fragments. The G allele was also independently associated with insulin resistance, impaired pancreatic β cell function, and incretin effect during the OGTT. CONCLUSION In NASH, the LOX-1 polymorphism is associated with liver disease severity and may predispose to CVD through modulation of postprandial small TRLPs and adipokine balance and to diabetes by affecting both insulin secretion and insulin sensitivity.
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113
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Kučera O, Lotková H, Staňková P, Podhola M, Roušar T, Mezera V, Cervinková Z. Is rat liver affected by non-alcoholic steatosis more susceptible to the acute toxic effect of thioacetamide? Int J Exp Pathol 2011; 92:281-9. [PMID: 21410800 DOI: 10.1111/j.1365-2613.2011.00765.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Non-alcoholic fatty liver disease (NAFLD) is the most common chronic condition of the liver in the western world. There is only little evidence about altered sensitivity of steatotic liver to acute toxic injury. The aim of this project was to test whether hepatic steatosis sensitizes rat liver to acute toxic injury induced by thioacetamide (TAA). Male Sprague-Dawley rats were fed ad libitum a standard pelleted diet (ST-1, 10% energy fat) and high-fat gelled diet (HFGD, 71% energy fat) for 6 weeks and then TAA was applied intraperitoneally in one dose of 100 mg/kg. Animals were sacrificed in 24-, 48- and 72-h interval after TAA administration. We assessed the serum biochemistry, the hepatic reduced glutathione, thiobarbituric acid reactive substances, cytokine concentration, the respiration of isolated liver mitochondria and histopathological samples (H+E, Sudan III, bromodeoxyuridine [BrdU] incorporation). Activities of alanine aminotransferase, aspartate aminotransferase and alkaline phosphatase and concentration of serum bilirubin were significantly higher in HFGD groups after application of TAA, compared to ST-1. There were no differences in activities of respiratory complexes I and II. Serum tumour necrosis factor alpha at 24 and 48 h, liver tissue interleukin-6 at 72 h and transforming growth factor β1 at 24 and 48 h were elevated in TAA-administrated rats fed with HFGD, but not ST-1. TAA-induced centrilobular necrosis and subsequent regenerative response of the liver were higher in HFGD-fed rats in comparison with ST-1. Liver affected by NAFLD, compared to non-steatotic liver, is more sensitive to toxic effect of TAA.
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Affiliation(s)
- Otto Kučera
- Department of Physiology, Faculty of Medicine in Hradec Králové, Charles University in Prague, Hradec Králové, Czech Republic.
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