scholarly journals Hepatic Insulin Resistance Is Not Pathway Selective in Humans With Nonalcoholic Fatty Liver Disease

2020 ◽  
Author(s):  
Kasper W. ter Horst ◽  
Daniel F. Vatner ◽  
Dongyan Zhang ◽  
Gary W. Cline ◽  
Mariette T. Ackermans ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Bariatric Surgery ◽  
Liver Disease ◽  
Fatty Liver ◽  
Insulin Signaling ◽  
Fatty Liver Disease ◽  
De Novo ◽  
Glucose Production ◽  
Hepatic Insulin Resistance ◽  
Alcoholic Fatty Liver

<b>Objective</b>: Both glucose and triglyceride production are increased in Type 2 diabetes and non-alcoholic fatty liver disease (NAFLD). For decades, the leading hypothesis to explain these paradoxical observations has been selective hepatic insulin resistance, wherein insulin drives <i>de novo</i> lipogenesis (DNL), while failing to suppress glucose production. Here, we aimed to test this hypothesis in humans. <p><b>Research Design and Methods</b>: We recruited obese subjects who met criteria for bariatric surgery with (n=16) or without (n=15) NAFLD and assessed: i) insulin-mediated regulation of hepatic and peripheral glucose metabolism using hyperinsulinemic-euglycemic clamps with [6,6-<sup>2</sup>H<sub>2</sub>]glucose, ii) fasting and carbohydrate-driven hepatic DNL using deuterated water (<sup>2</sup>H<sub>2</sub>O), and iii) hepatocellular insulin signaling in liver biopsies collected during bariatric surgery.</p> <p><b>Results</b>: As compared with subjects without NAFLD, subjects with NAFLD demonstrated impaired insulin-mediated suppression of glucose production and attenuated -not increased- glucose-stimulated/high-insulin lipogenesis. Fructose-stimulated/low-insulin lipogenesis was intact. Hepatocellular insulin signaling, assessed for the first time in humans, exhibited a proximal block in insulin-resistant subjects: signaling was attenuated from the level of the insulin receptor through both glucose <i>and</i> lipogenesis pathways. The carbohydrate-regulated lipogenic transcription factor <i>ChREBP</i> was increased in subjects with NAFLD. </p> <b>Conclusions</b>: Acute increases in lipogenesis in humans with NAFLD are not explained by altered molecular regulation of lipogenesis through a paradoxical increase in lipogenic insulin action; rather, increases in lipogenic substrate availability may be the key. <a></a>

scholarly journals Hepatic Insulin Resistance Is Not Pathway Selective in Humans With Nonalcoholic Fatty Liver Disease

2020 ◽  
Author(s):  
Kasper W. ter Horst ◽  
Daniel F. Vatner ◽  
Dongyan Zhang ◽  
Gary W. Cline ◽  
Mariette T. Ackermans ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Bariatric Surgery ◽  
Liver Disease ◽  
Fatty Liver ◽  
Insulin Signaling ◽  
Fatty Liver Disease ◽  
De Novo ◽  
Glucose Production ◽  
Hepatic Insulin Resistance ◽  
Alcoholic Fatty Liver

<b>Objective</b>: Both glucose and triglyceride production are increased in Type 2 diabetes and non-alcoholic fatty liver disease (NAFLD). For decades, the leading hypothesis to explain these paradoxical observations has been selective hepatic insulin resistance, wherein insulin drives <i>de novo</i> lipogenesis (DNL), while failing to suppress glucose production. Here, we aimed to test this hypothesis in humans. <p><b>Research Design and Methods</b>: We recruited obese subjects who met criteria for bariatric surgery with (n=16) or without (n=15) NAFLD and assessed: i) insulin-mediated regulation of hepatic and peripheral glucose metabolism using hyperinsulinemic-euglycemic clamps with [6,6-<sup>2</sup>H<sub>2</sub>]glucose, ii) fasting and carbohydrate-driven hepatic DNL using deuterated water (<sup>2</sup>H<sub>2</sub>O), and iii) hepatocellular insulin signaling in liver biopsies collected during bariatric surgery.</p> <p><b>Results</b>: As compared with subjects without NAFLD, subjects with NAFLD demonstrated impaired insulin-mediated suppression of glucose production and attenuated -not increased- glucose-stimulated/high-insulin lipogenesis. Fructose-stimulated/low-insulin lipogenesis was intact. Hepatocellular insulin signaling, assessed for the first time in humans, exhibited a proximal block in insulin-resistant subjects: signaling was attenuated from the level of the insulin receptor through both glucose <i>and</i> lipogenesis pathways. The carbohydrate-regulated lipogenic transcription factor <i>ChREBP</i> was increased in subjects with NAFLD. </p> <b>Conclusions</b>: Acute increases in lipogenesis in humans with NAFLD are not explained by altered molecular regulation of lipogenesis through a paradoxical increase in lipogenic insulin action; rather, increases in lipogenic substrate availability may be the key. <a></a>

scholarly journals Physiological Disturbance in Fatty Liver Energy Metabolism Converges on IGFBP2 Abundance and Regulation in Mice and Men

2020 ◽  
Vol 21 (11) ◽  
pp. 4144 ◽  
Author(s):  
Pia Fahlbusch ◽  
Birgit Knebel ◽  
Tina Hörbelt ◽  
David Monteiro Barbosa ◽  
Aleksandra Nikolic ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Liver Disease ◽  
Energy Metabolism ◽  
Fatty Liver ◽  
Lipid Accumulation ◽  
Fatty Liver Disease ◽  
De Novo ◽  
De Novo Lipogenesis ◽  
Hepatic Insulin Resistance ◽  
Alcoholic Fatty Liver

Fatty liver occurs from simple steatosis with accumulated hepatic lipids and hepatic insulin resistance to severe steatohepatitis, with aggravated lipid accumulation and systemic insulin resistance, but this progression is still poorly understood. Analyses of hepatic gene expression patterns from alb-SREBP-1c mice with moderate, or aP2-SREBP-1c mice with aggravated, hepatic lipid accumulation revealed IGFBP2 as key nodal molecule differing between moderate and aggravated fatty liver. Reduced IGFBP2 expression in aggravated fatty liver was paralleled with promoter hypermethylation, reduced hepatic IGFBP2 secretion and IGFBP2 circulating in plasma. Physiologically, the decrease of IGFBP2 was accompanied with reduced fatty acid oxidation and increased de novo lipogenesis potentially mediated by IGF1 in primary hepatocytes. Furthermore, methyltransferase and sirtuin activities were enhanced. In humans, IGFBP2 serum concentration was lower in obese men with non-alcoholic fatty liver disease (NAFLD) and steatohepatitis (NASH) compared to non-obese controls, and liver fat reduction by weight-loss intervention correlated with an increase of IGFBP2 serum levels. In conclusion, hepatic IGFBP2 abundance correlates to its circulating level and is related to hepatic energy metabolism and de novo lipogenesis. This designates IGFBP2 as non-invasive biomarker for fatty liver disease progression and might further provide an additional variable for risk prediction for pathogenesis of fatty liver in diabetes subtype clusters.

scholarly journals Role of Insulin Resistance in MAFLD

2021 ◽  
Vol 22 (8) ◽  
pp. 4156
Author(s):  
Yoshitaka Sakurai ◽  
Naoto Kubota ◽  
Toshimasa Yamauchi ◽  
Takashi Kadowaki
Keyword(s):  
Insulin Resistance ◽  
Liver Disease ◽  
Fatty Liver ◽  
Fatty Liver Disease ◽  
De Novo Lipogenesis ◽  
Hepatic Insulin Resistance ◽  
Metabolic Dysfunction ◽  
Alcoholic Fatty Liver ◽  
Fat Accumulation

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.

scholarly journals Beneficial effect of omarigliptin on diabetic patients with non-alcoholic fatty liver disease/non-alcoholic steatohepatitis

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Sachiko Hattori ◽  
Kazuomi Nomoto ◽  
Tomohiko Suzuki ◽  
Seishu Hayashi
Keyword(s):  
Insulin Resistance ◽  
Liver Disease ◽  
Liver Function ◽  
Fatty Liver ◽  
Fatty Liver Disease ◽  
Hepatic Insulin Resistance ◽  
Diabetic Patients ◽  
Alcoholic Fatty Liver ◽  
Dpp4 Inhibitor ◽  
Alcoholic Fatty Liver Disease

Abstract Background Dipeptidyl peptidase 4 (DPP4) is a serine exopeptidase able to inactivate various oligopeptides, and also a hepatokine. Hepatocyte-specific overexpression of DPP4 is associated with hepatic insulin resistance and liver steatosis. Method We examined whether weekly DPP4 inhibitor omarigliptin (OMG) can improve liver function as well as levels of inflammation and insulin resistance in type 2 diabetic patients with non-alcoholic fatty liver disease (NAFLD). Further, we investigated the effects of OMG in a diabetic patient with biopsy-confirmed nonalcoholic steatohepatitis (NASH). Results In NAFLD patients, OMG significantly decreased levels of aminotransferase, aspartate aminotransferase, gamma-glutamyl transpeptidase, homeostatic model assessment of insulin resistance (HOMA-IR), and high-sensitivity C-reactive protein (hsCRP), while no significant change was seen in hemoglobin A1c or body mass index. In the NASH patient, liver function improved markedly, and levels of the hepatic fibrosis marker FIB-4 decreased in parallel with HOMA-IR and hsCRP. Slight but clear improvements in intrahepatic fat deposition and fibrosis appeared to be seen on diagnostic ultrasonography. Conclusion Weekly administration of the DPP4 inhibitor OMG in ameliorating hepatic insulin resistance may cause beneficial effects in liver with NAFLD/NASH.

scholarly journals Mechanism of Hepatic Insulin Resistance in Non-alcoholic Fatty Liver Disease

2004 ◽  
Vol 279 (31) ◽  
pp. 32345-32353 ◽  
Author(s):  
Varman T. Samuel ◽  
Zhen-Xiang Liu ◽  
Xianqin Qu ◽  
Benjamin D. Elder ◽  
Stefan Bilz ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Liver Disease ◽  
Fatty Liver ◽  
Fatty Liver Disease ◽  
Hepatic Insulin Resistance ◽  
Alcoholic Fatty Liver ◽  
Alcoholic Fatty Liver Disease

scholarly journals Beneficial effect of omarigliptin on diabetic patients with non-alcoholic fatty liver disease/non-alcoholic steatohepatitis

2020 ◽  
Author(s):  
Sachiko Hattori ◽  
Kazuhiro Nomoto ◽  
Tomohiko Suzuki ◽  
Seishu Hayashi
Keyword(s):  
Insulin Resistance ◽  
Liver Disease ◽  
Liver Function ◽  
Fatty Liver ◽  
Fatty Liver Disease ◽  
Hepatic Insulin Resistance ◽  
Diabetic Patients ◽  
Model Assessment ◽  
Alcoholic Fatty Liver ◽  
Alcoholic Fatty Liver Disease

Abstract Background: Dipeptidyl peptidase 4 (DPP4) is a serine exopeptidase able to inactivate various oligopeptides and also a hepatokine. Hepatocyte-specific overexpression of DPP4 is associated with hepatic insulin resistance and liver steatosis. Method: We examined whether weekly DPP4 inhibitor omarigliptin (OMG) improves liver function as well as levels of inflammation and insulin resistance in type 2 diabetic patients with non-alcoholic fatty liver disease (NAFLD). Furthermore, we tried OMG in a diabetic patient with biopsy-confirmed nonalcoholic steatohepatitis (NASH). Results: In NAFLD patients, OMG significantly decreased levels of aminotransferase (ALT), aspartate aminotransferase (AST), gamma-glutamyl transpeptidase (gGTP), homeostatic model assessment of insulin resistance (HOMA-IR), and high-sensitivity C-reactive protein (hsCRP), while no significant change was seen in hemoglobin A1c (HbA1c) or body mass index (BMI). In a NASH patient, liver function had improved markedly, and the hepatic fibrosis marker FIB-4 decreased in parallel with HOMA-IR and hsCRP. Improvements in intrahepatic fat deposition and fibrosis appeared to be seen on ultrasonography.Conclusion: The effects of OMG in ameliorating hepatic insulin resistance may lead to decreasing intrahepatic fat accumulation and improving intrahepatic adipose inflammation in NAFLD/NASH.Trial registration: UMIN Clinical Registry (UMIN000029288). Registered 22 September, 2017, https://upload.umin.ac.jp/UMIN000029288

scholarly journals Non-alcoholic fatty liver disease (NAFLD) – epidemic of the XXI century

2018 ◽  
Vol 72 ◽  
pp. 659-670 ◽  
Author(s):  
Dominika Maciejewska ◽  
Ewa Stachowska
Keyword(s):  
Insulin Resistance ◽  
Fatty Acids ◽  
Liver Disease ◽  
Fatty Liver ◽  
Fatty Liver Disease ◽  
De Novo ◽  
Serum Insulin ◽  
De Novo Lipogenesis ◽  
Alcoholic Fatty Liver ◽  
Alcoholic Fatty Liver Disease

The term “non-alcoholic fatty liver disease” (NAFLD) was first introduced by Ludwig in 1980. He described NAFLD as a liver disease characterized by lipid accumulation in the hepatocytes of people who do not abuse alcohol (<20g/ethanol/day). NAFLD comprises of a range of disorders, including simple fatty liver without the symptoms of damaged hepatocytes, as well as complex fatty liver with an ongoing inflammation and developing fibrosis. It is estimated that 2-44% of adult Europeans will develop a fatty liver. The pathogenesis and development of NAFLD is a complicated process involving numerous factors, such as: dyslipidemia, insulin resistance, overweight, obesity, mitochondrial dysfunction, oxidative stress, the development of an inflammatory state, the disorders of the metabolism of fat tissue, dysbiosis and genetic factors. Because the mechanism of the illness is based on many factors, the multiple hits hypothesis serves as the new and generally standard approach to this pathological unit. The basis of this theory is the development of insulin resistance, which is one of the main causes of steatosis. The consequence of insulin resistance is an increased glucose level (associated with impaired insulin receptors) and excessive insulin production leading to elevated levels of this hormone in the serum. Insulin resistance causes continuous stimulation of gluconeogenesis and hyperglycemia. On the other hand, hyperinsulinemia stimulates the hepatic synthesis of the de novo lipogenesis and leads to steatosis. NAFLD is also closely connected to the metabolism disorders of fatty acids. The pathomechanism of the illness includes an increased concentration of FFA in blood, an increase in the biosynthesis of fatty acids in the liver, as well as disorders in the process of β-oxidation.

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