scholarly journals Hepatocyte-Specific Disruption of CD36 Attenuates Fatty Liver and Improves Insulin Sensitivity in HFD-Fed Mice

Endocrinology ◽  
2015 ◽  
Vol 157 (2) ◽  
pp. 570-585 ◽  
Author(s):  
Camella G. Wilson ◽  
Jennifer L. Tran ◽  
Derek M. Erion ◽  
Nicholas B. Vera ◽  
Maria Febbraio ◽  
...  
Keyword(s):  
Insulin Sensitivity ◽  
Fatty Liver ◽  
Inflammatory Markers ◽  
Genetic Model ◽  
Liver Lipid ◽  
Janus Kinase ◽  
Whole Body ◽  
Nonalcoholic Fatty Liver ◽  
Liver Lipid Content ◽  
Liver Triglycerides

Abstract CD36/FAT (fatty acid translocase) is associated with human and murine nonalcoholic fatty liver disease, but it has been unclear whether it is simply a marker or whether it directly contributes to disease pathogenesis. Mice with hepatocyte-specific deletion of Janus kinase 2 (JAK2L mice) have increased circulating free fatty acids (FAs), dramatically increased hepatic CD36 expression and profound fatty liver. To investigate the role of elevated CD36 in the development of fatty liver, we studied two models of hepatic steatosis, a genetic model (JAK2L mice) and a high-fat diet (HFD)-induced steatosis model. We deleted Cd36 specifically in hepatocytes of JAK2L mice to generate double knockouts and from wild-type mice to generate CD36L single-knockout mice. Hepatic Cd36 disruption in JAK2L livers significantly improved steatosis by lowering triglyceride, diacylglycerol, and cholesterol ester content. The largest differences in liver triglycerides were in species comprised of oleic acid (C18:1). Reduction in liver lipids correlated with an improvement in the inflammatory markers that were elevated in JAK2L mice, namely aspartate aminotransferase and alanine transaminase. Cd36 deletion in mice on HFD (CD36L-HFD) reduced liver lipid content and decreased hepatic 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene-FA uptake as compared with CON-HFD. Additionally, CD36L-HFD mice had improved whole-body insulin sensitivity and reduced liver and serum inflammatory markers. Therefore, CD36 directly contributes to development of fatty liver under conditions of elevated free FAs by modulating the rate of FA uptake by hepatocytes. In HFD-fed animals, disruption of hepatic Cd36 protects against associated systemic inflammation and insulin resistance.

scholarly journals Apolipoprotein CIII Overexpression-Induced Hypertriglyceridemia Increases Nonalcoholic Fatty Liver Disease in Association with Inflammation and Cell Death

2017 ◽  
Vol 2017 ◽  
pp. 1-18 ◽  
Author(s):  
Adriene A. Paiva ◽  
Helena F. Raposo ◽  
Amarylis C. B. A. Wanschel ◽  
Tarlliza R. Nardelli ◽  
Helena C. F. Oliveira
Keyword(s):  
Cell Death ◽  
Liver Disease ◽  
Fatty Liver ◽  
Nonalcoholic Fatty Liver Disease ◽  
Lipid Content ◽  
Fatty Liver Disease ◽  
Liver Lipid ◽  
Hepatic Insulin Resistance ◽  
Nonalcoholic Fatty Liver ◽  
Liver Lipid Content

Nonalcoholic fatty liver disease (NAFLD) is the principal manifestation of liver disease in obesity and metabolic syndrome. By comparing hypertriglyceridemic transgenic mice expressing apolipoprotein (apo) CIII with control nontransgenic (NTg) littermates, we demonstrated that overexpression of apoCIII, independent of a high-fat diet (HFD), produces NAFLD-like features, including increased liver lipid content; decreased antioxidant power; increased expression of TNFα, TNFα receptor, cleaved caspase-1, and interleukin-1β; decreased expression of adiponectin receptor-2; and increased cell death. This phenotype is aggravated and additional NAFLD features are differentially induced in apoCIII mice fed a HFD. HFD induced glucose intolerance together with increased gluconeogenesis, indicating hepatic insulin resistance. Additionally, the HFD led to marked increases in plasma TNFα (8-fold) and IL-6 (60%) in apoCIII mice. Cell death signaling (Bax/Bcl2), effector (caspase-3), and apoptosis were augmented in apoCIII mice regardless of whether a HFD or a low-fat diet was provided. Fenofibrate treatment reversed several of the effects associated with diet and apoCIII expression but did not normalize inflammatory traits even when liver lipid content was fully corrected. These results indicate that apoCIII and/or hypertriglyceridemia plays a major role in liver inflammation and cell death, which in turn increases susceptibility to and the severity of diet-induced NAFLD.

scholarly journals Short-term exercise reduces markers of hepatocyte apoptosis in nonalcoholic fatty liver disease

2012 ◽  
Vol 113 (1) ◽  
pp. 1-6 ◽  
Author(s):  
Ciaran E. Fealy ◽  
Jacob M. Haus ◽  
Thomas P. J. Solomon ◽  
Mangesh Pagadala ◽  
Chris A. Flask ◽  
...  
Keyword(s):  
Liver Disease ◽  
Insulin Sensitivity ◽  
Fatty Liver ◽  
Nonalcoholic Fatty Liver Disease ◽  
Fatty Liver Disease ◽  
Fat Oxidation ◽  
Whole Body ◽  
Hepatocyte Apoptosis ◽  
Short Term ◽  
Nonalcoholic Fatty Liver

Increased hepatocyte apoptosis is a hallmark of nonalcoholic fatty liver disease (NAFLD) and contributes to the profibrogenic state responsible for the progression to nonalcoholic steatohepatitis (NASH). Strategies aimed at reducing apoptosis may result in better outcomes for individuals with NAFLD. We therefore examined the effect of a short-term exercise program on markers of apoptosis—plasma cytokeratin 18 (CK18) fragments, alanine aminotransferase (ALT), aspartate aminotransferase (AST), soluble Fas (sFas), and sFas ligand (sFasL)—in 13 obese individuals with NAFLD [body mass index 35.2 ± 1.2 kg/m2, >5% intrahepatic lipid (IHL) assessed by 1H-MR spectroscopy]. Exercise consisted of treadmill walking for 60 min/day on 7 consecutive days at ∼85% of maximal heart rate. Additionally, subjects underwent an oral glucose tolerance test and a maximal oxygen consumption (V̇o2max) test before and after the exercise intervention. The Matsuda index was used to assess insulin sensitivity. We observed significant decreases in CK18 fragments (558.4 ± 106.8 vs. 323.4 ± 72.5 U/l, P < 0.01) and ALT (30.2 ± 5.1 vs. 24.3 ± 4.8 U/l, P < 0.05), and an increase in whole body fat oxidation (49.3 ± 6.1 vs. 69.4 ± 7.1 mg/min, P < 0.05), while decreases in circulating sFasL approached statistical significance (66.5 ± 6.0 vs. 63.0 ± 5.7 pg/ml, P = 0.06), as did the relationship between percent change in circulating CK18 fragments and ALT (r = 0.55, P = 0.05). We also observed a significant correlation between changes in fat oxidation and circulating sFasL (rho = −0.65, P < 0.05). There was no change in IHL following the intervention (18.2 ± 2.5 vs. 17.5 ± 2.1%, NS). We conclude that short-term exercise reduces a circulatory marker of hepatocyte apoptosis in obese individuals with NAFLD and propose that changes in the proapoptotic environment may be mediated through improved insulin sensitivity and increased oxidative capacity.

scholarly journals Hepatic IKKε expression is dispensable for high-fat feeding-induced increases in liver lipid content and alterations in glucose tolerance

2020 ◽  
Vol 318 (1) ◽  
pp. E11-E21
Author(s):  
J. Jason Collier ◽  
Heidi M. Batdorf ◽  
Tamra M. Mendoza ◽  
David H. Burk ◽  
Thomas M. Martin ◽  
...  
Keyword(s):  
Weight Gain ◽  
Insulin Sensitivity ◽  
Glucose Tolerance ◽  
Liver Lipid ◽  
Nuclear Factor Κb ◽  
Whole Body ◽  
High Fat ◽  
Glycogen Accumulation ◽  
Liver Lipid Content ◽  
Sites Of Action

There are endocrine and immunological changes that occur during onset and progression of the overweight and obese states. The inhibitor of nuclear factor-κB kinase-ε (IKKε) was originally described as an inducible protein kinase; whole body gene deletion or systemic pharmaceutical targeting of this kinase improved insulin sensitivity and glucose tolerance in mice. To investigate the primary sites of action associated with IKKε during weight gain, we describe the first mouse line with conditional elimination of IKKε in the liver (IKKεAlb–/–). IKKεAlb–/– mice and littermate controls gain weight, show similar changes in body composition, and do not display any improvements in insulin sensitivity or whole body glucose tolerance. These studies were conducted using breeder chow diets and matched low- vs. high-fat diets. While glycogen accumulation in the liver is reduced in IKKεAlb–/– mice, lipid storage in liver is similar in IKKεAlb–/– mice and littermate controls. Our results using IKKεAlb–/– mice suggest that the primary action of this kinase to impact insulin sensitivity during weight gain lies predominantly within extrahepatic tissues.

scholarly journals Maternal Hyperleptinemia Improves Offspring Insulin Sensitivity in Mice

Endocrinology ◽  
2016 ◽  
Vol 157 (7) ◽  
pp. 2636-2648 ◽  
Author(s):  
Omonseigho O. Talton ◽  
Kathleen A. Pennington ◽  
Kelly E. Pollock ◽  
Keenan Bates ◽  
Lixin Ma ◽  
...  
Keyword(s):  
Liver Disease ◽  
Insulin Sensitivity ◽  
Glucose Tolerance ◽  
Fatty Liver ◽  
Nonalcoholic Fatty Liver Disease ◽  
Fatty Liver Disease ◽  
Leptin Receptor ◽  
Wild Type ◽  
Nonalcoholic Fatty Liver ◽  
Liver Triglycerides

Maternal obesity and gestational diabetes are prevalent worldwide. Offspring of mothers with these conditions weigh more and are predisposed to metabolic syndrome. A hallmark of both conditions is maternal hyperleptinemia, but the role of elevated leptin levels during pregnancy on developmental programming is largely unknown. We previously found that offspring of hyperleptinemic mothers weighed less and had increased activity. The goal of this study was to determine whether maternal leptin affects offspring insulin sensitivity by investigating offspring glucose metabolism and lipid accumulation. Offspring from two maternal hyperleptinemic models were compared. The first model of hyperleptinemia is the Leprdb/+ mouse, which has a mutation in one copy of the gene that encodes the leptin receptor, resulting in a truncated long form of the receptor, and hyperleptinemia. Wild-type females served as the control for the Leprdb/+ females. For the second hyperleptinemic model, wild-type females were implanted with miniosmotic pumps, which released leptin (350 ng/h) or saline (as the control) just prior to mating and throughout gestation. In the offspring of these dams, we measured glucose tolerance; serum leptin, insulin, and triglyceride levels; liver triglycerides; pancreatic α- and β-cell numbers; body composition; incidence of nonalcoholic fatty liver disease; and the expression of key metabolic genes in the liver and adipose tissue. We found that the offspring of hyperleptinemic dams exhibited improved glucose tolerance, reduced insulin and leptin concentrations, reduced liver triglycerides, and a lower incidence of nonalcoholic fatty liver disease. Overall, maternal hyperleptinemia was beneficial for offspring glucose and lipid metabolism.

scholarly journals Comparative Evaluation of Whole Body and Hepatic Insulin Resistance Using Indices from Oral Glucose Tolerance Test in Morbidly Obese Subjects with Nonalcoholic Fatty Liver Disease

2010 ◽  
Vol 2010 ◽  
pp. 1-7 ◽  
Author(s):  
Kamran Qureshi ◽  
Ronald H. Clements ◽  
Fahad Saeed ◽  
Gary A. Abrams
Keyword(s):  
Insulin Sensitivity ◽  
Fatty Liver ◽  
Glucose Tolerance Test ◽  
Tolerance Test ◽  
Whole Body ◽  
Morbidly Obese ◽  
Oral Glucose ◽  
Sensitivity Index ◽  
Insulin Sensitivity Index ◽  
Nonalcoholic Fatty Liver

Nonalcoholic Fatty Liver Disease (NAFLD) is the hepatic manifestation of metabolic syndrome and is a marker of Insulin Resistance (IR). Euglycemic-hyperinsulinemic clamp is the gold standard for measuring whole body IR (hepatic + peripheral IR). However, it is an invasive and expensive procedure. Homeostasis Model Assessment Index for Insulin Sensitivity (HOMA-IS), Quantitative Insulin Sensitivity Check Index (QUICKI) for hepatic IR and Insulin Sensitivity Index (), and Whole Body Insulin Sensitivity Index (WBISI) for whole body IR are the indices calculated after Oral Glucose Tolerance Test (OGTT). We used these indices as noninvasive methods of IR (inverse of insulin sensitivity) estimation and compared hepatic/peripheral components of whole body IR in NAFLD.Methods. 113 morbidly obese, nondiabetic subjects who underwent gastric bypass surgery and intraoperative liver biopsy were included in the study. OGTT was performed preoperatively and the indices were calculated. Subjects were divided into closely matched groups as normal, fatty liver (FL) and Non-Alcoholic Steatohepatitis (NASH) based on histology.Results. Whole body IR was significantly higher in both FL and NASH groups (NAFLD) as compared to Normal, while hepatic IR was higher only in NASH from Normal.Conclusions. FL is a manifestation of peripheral IR but not hepatic IR.

scholarly journals Doxepin Exacerbates Renal Damage, Glucose Intolerance, Nonalcoholic Fatty Liver Disease and Urinary Chromium Loss in Obese Mice

2021 ◽  
Vol 14 (3) ◽  
pp. 267
Author(s):  
Geng-Ruei Chang ◽  
Po-Hsun Hou ◽  
Wei-Cheng Yang ◽  
Chao-Min Wang ◽  
Pei-Shan Fan ◽  
...  
Keyword(s):  
Liver Disease ◽  
Fatty Liver ◽  
Nonalcoholic Fatty Liver Disease ◽  
Glucose Intolerance ◽  
Fatty Liver Disease ◽  
Renal Damage ◽  
Liver Lipid ◽  
Interleukin 1 ◽  
Mrna Levels ◽  
Nonalcoholic Fatty Liver

Doxepin is commonly prescribed for depression and anxiety treatment. Doxepin-related disruptions to metabolism and renal/hepatic adverse effects remain unclear; thus, the underlying mechanism of action warrants further research. Here, we investigated how doxepin affects lipid change, glucose homeostasis, chromium (Cr) distribution, renal impairment, liver damage, and fatty liver scores in C57BL6/J mice subjected to a high-fat diet and 5 mg/kg/day doxepin treatment for eight weeks. We noted that the treated mice had higher body, kidney, liver, retroperitoneal, and epididymal white adipose tissue weights; serum and liver triglyceride, alanine aminotransferase, aspartate aminotransferase, blood urea nitrogen, and creatinine levels; daily food efficiency; and liver lipid regulation marker expression. They also demonstrated exacerbated insulin resistance and glucose intolerance with lower Akt phosphorylation, GLUT4 expression, and renal damage as well as higher reactive oxygen species and interleukin 1 and lower catalase, superoxide dismutase, and glutathione peroxidase levels. The treated mice had a net-negative Cr balance due to increased urinary excretion, leading to Cr mobilization, delaying hyperglycemia recovery. Furthermore, they had considerably increased fatty liver scores, paralleling increases in adiponectin, FASN, PNPLA3, FABP4 mRNA, and SREBP1 mRNA levels. In conclusion, doxepin administration potentially worsens renal injury, nonalcoholic fatty liver disease, and diabetes.

scholarly journals Prenatal hyperandrogenism induces alterations that affect liver lipid metabolism

2016 ◽  
Vol 230 (1) ◽  
pp. 67-79 ◽  
Author(s):  
Giselle Adriana Abruzzese ◽  
Maria Florencia Heber ◽  
Silvana Rocio Ferreira ◽  
Leandro Martin Velez ◽  
Roxana Reynoso ◽  
...  
Keyword(s):  
Metabolic Syndrome ◽  
Lipid Metabolism ◽  
Glucose Tolerance ◽  
Fatty Liver ◽  
Lipid Content ◽  
Liver Lipid ◽  
Acid Oxidation ◽  
Liver Lipid Content ◽  
Increased Risk ◽  
Liver Lipid Metabolism

Prenatal hyperandrogenism is hypothesized as one of the main factors contributing to the development of polycystic ovary syndrome (PCOS). PCOS patients have high risk of developing fatty liver and steatosis. This study aimed to evaluate the role of prenatal hyperandrogenism in liver lipid metabolism and fatty liver development. Pregnant rats were hyperandrogenized with testosterone. At pubertal age, the prenatally hyperandrogenized (PH) female offspring displayed both ovulatory (PHov) and anovulatory (PHanov) phenotypes that mimic human PCOS features. We evaluated hepatic transferases, liver lipid content, the balance between lipogenesis and fatty acid oxidation pathway, oxidant/antioxidant balance and proinflammatory status. We also evaluated the general metabolic status through growth rate curve, basal glucose and insulin levels, glucose tolerance test, HOMA-IR index and serum lipid profile. Although neither PH group showed signs of liver lipid content, the lipogenesis and fatty oxidation pathways were altered. The PH groups also showed impaired oxidant/antioxidant balance, a decrease in the proinflammatory pathway (measured by prostaglandin E2 and cyclooxygenase-2 levels), decreased glucose tolerance, imbalance of circulating lipids and increased risk of metabolic syndrome. We conclude that prenatal hyperandrogenism generates both PHov and PHanov phenotypes with signs of liver alterations, imbalance in lipid metabolism and increased risk of developing metabolic syndrome. The anovulatory phenotype showed more alterations in liver lipogenesis and a more impaired balance of insulin and glucose metabolism, being more susceptible to the development of steatosis.

scholarly journals Insulin sensitivity variations in apparently healthy Arab male subjects: correlation with insulin and C peptide

2021 ◽  
Vol 9 (2) ◽  
pp. e002039
Author(s):  
Noor Suleiman ◽  
Meis Alkasem ◽  
Shaimaa Hassoun ◽  
Ibrahem Abdalhakam ◽  
Ilham Bettahi ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Insulin Sensitivity ◽  
Inflammatory Markers ◽  
The Other ◽  
Whole Body ◽  
Oxidative Stress Markers ◽  
C Peptide ◽  
Stress Markers ◽  
Wide Range ◽  
Apparently Healthy

IntroductionDecreased insulin sensitivity occurs early in type 2 diabetes (T2D). T2D is highly prevalent in the Middle East and North Africa regions. This study assessed the variations in insulin sensitivity in normal apparently healthy subjects and the levels of adiponectin, adipsin and inflammatory markers.Research design and methodsA total of 60 participants (aged 18–45, body mass index <28) with a normal oral glucose tolerance test (OGTT) completed hyperinsulinemic-euglycemic clamp (40 mU/m2/min) and body composition test by dual-energy X-ray absorptiometry scan. Blood samples were assayed for glucose, insulin, C peptide, inflammatory markers, oxidative stress markers, adiponectin and adipsin.ResultsThe subjects showed wide variations in the whole-body glucose disposal rate (M value) from 2 to 20 mg/kg/min and were divided into three groups: most responsive (M>12 mg/kg/min, n=17), least responsive (M≤6 mg/kg/min, n=14) and intermediate responsive (M=6.1–12 mg/kg/min, n=29). Insulin and C peptide responses to OGTT were highest among the least insulin sensitive group. Triglycerides, cholesterol, alanine transaminase (ALT) and albumin levels were higher in the least responsive group compared with the other groups. Among the inflammatory markers, C reactive protein (CRP) was highest in the least sensitivity group compared with the other groups; however, there were no differences in the level of soluble receptor for advanced glycation end products and Tumor Necrosis Factor Receptor Superfamily 1B (TNFRS1B). Plasma levels of insulin sensitivity markers, adiponectin and adipsin, and oxidative stress markers, oxidized low-density lipoprotein, total antioxidant capacity and glutathione peroxidase 1, were similar between the groups.ConclusionsA wide range in insulin sensitivity and significant differences in triglycerides, cholesterol, ALT and CRP concentrations were observed despite the fact that the study subjects were homogenous in terms of age, gender and ethnic background, and all had normal screening comprehensive chemistry and normal glucose response to OGTT. The striking differences in insulin sensitivity reflect differences in genetic predisposition and/or environmental exposure. The low insulin sensitivity status associated with increased insulin level may represent an early stage of metabolic abnormality.

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