scholarly journals Caloric Restriction Reverses Hepatic Insulin Resistance and Steatosis in Rats with Low Aerobic Capacity

Endocrinology ◽  
2010 ◽  
Vol 151 (11) ◽  
pp. 5157-5164 ◽  
Author(s):  
Thomas A. Bowman ◽  
Sadeesh K. Ramakrishnan ◽  
Meenakshi Kaw ◽  
Sang Jun Lee ◽  
Payal R. Patel ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Insulin Resistance ◽  
Caloric Restriction ◽  
Visceral Obesity ◽  
Insulin Clearance ◽  
Hepatic Insulin Resistance ◽  
The Metabolic Syndrome ◽  
Cell Adhesion Molecule 1 ◽  
Muscle Triglyceride

Rats selectively bred for low aerobic running capacity exhibit the metabolic syndrome, including hyperinsulinemia, insulin resistance, visceral obesity, and dyslipidemia. They also exhibit features of nonalcoholic steatohepatitis, including chicken-wire fibrosis, inflammation, and oxidative stress. Hyperinsulinemia in these rats is associated with impaired hepatic insulin clearance. The current studies aimed to determine whether these metabolic abnormalities could be reversed by caloric restriction (CR). CR by 30% over a period of 2–3 months improved insulin clearance in parallel to inducing the protein content and activation of the carcinoembryonic antigen-related cell adhesion molecule 1, a main player in hepatic insulin extraction. It also reduced glucose and insulin intolerance and serum and tissue (liver and muscle) triglyceride levels. Additionally, CR reversed inflammation, oxidative stress, and fibrosis in liver. The data support a significant role of CR in the normalization of insulin and lipid metabolism in liver.

Lipid behavior in metabolic syndrome pathophysiology

2021 ◽  
Vol 17 ◽  
Author(s):  
Basheer Marzoog
Keyword(s):  
Insulin Resistance ◽  
Metabolic Syndrome ◽  
Lipid Level ◽  
Visceral Obesity ◽  
Insulin Resistance Syndrome ◽  
Chronic Inflammatory Response ◽  
Cell Dysfunction ◽  
Commensal Microbiota ◽  
The Metabolic Syndrome

: Undeniably, lipid plays an extremely important role in the homeostasis balance, since lipid contributes to the regulation of the metabolic processes. The metabolic syndrome pathogenesis is multi-pathway that composes neurohormonal disorders, endothelial cell dysfunction, metabolic disturbance, genetic predisposition, in addition to gut commensal microbiota. The heterogenicity of the possible mechanisms gives the metabolic syndrome its complexity and limitation of therapeutic accesses. The main pathological link that lipid contributes to the emergence of metabolic syndrome via central obesity and visceral obesity that consequently lead to oxidative stress and chronic inflammatory response promotion. Physiologically, a balance is kept between the adiponectin and adipokines level to maintain the lipid level in the organism. Clinically, extremely important to define the borders of the lipid level in which the pathogenesis of the metabolic syndrome is reversible, otherwise will be accompanied by irreversible complications and sequelae of the metabolic syndrome (cardiovascular, insulin resistance). The present paper is dedicated to providing novel insights into the role of lipid in the development of metabolic syndrome hence dyslipidemia is the initiator of insulin resistance syndrome (metabolic syndrome).

scholarly journals Targeted Disruption of Carcinoembryonic Antigen-Related Cell Adhesion Molecule 1 Promotes Diet-Induced Hepatic Steatosis and Insulin Resistance

Endocrinology ◽  
2009 ◽  
Vol 150 (8) ◽  
pp. 3503-3512 ◽  
Author(s):  
Elaine Xu ◽  
Marie-Julie Dubois ◽  
Nelly Leung ◽  
Alexandre Charbonneau ◽  
Claire Turbide ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Cell Adhesion ◽  
Hepatic Steatosis ◽  
Adhesion Molecule ◽  
Cell Adhesion Molecule ◽  
Insulin Clearance ◽  
Hepatic Insulin Resistance ◽  
High Fat ◽  
Related Cell ◽  
Cell Adhesion Molecule 1

Carcinoembryonic antigen-related cell adhesion molecule 1 (CC1) is a cell adhesion molecule within the Ig superfamily. The Tyr-phosphorylated isoform of CC1 (CC1-L) plays an important metabolic role in the regulation of hepatic insulin clearance. In this report, we show that CC1-deficient (Cc1−/−) mice are prone to hepatic steatosis, as revealed by significantly elevated hepatic triglyceride and both total and esterified cholesterol levels compared with age-matched wild-type controls. Cc1−/− mice were also predisposed to lipid-induced hepatic steatosis and dysfunction as indicated by their greater susceptibility to store lipids and express elevated levels of enzymatic markers of liver damage after chronic feeding of a high-fat diet. Hepatic steatosis in the Cc1−/− mice was linked to a significant increase in the expression of key lipogenic (fatty acid synthase, acetyl CoA carboxylase) and cholesterol synthetic (3-hydroxy-3-methylglutaryl-coenzyme A reductase) enzymes under the control of sterol regulatory element binding proteins-1c and -2 transcription factors. Cc1−/− mice also exhibited impaired insulin clearance, glucose intolerance, liver insulin resistance, and elevated hepatic expression of the key gluconeogenic transcriptional activators peroxisome proliferator-activated receptor-γ coactivator-1 and Forkhead box O1. Lack of CC1 also exacerbated both glucose intolerance and hepatic insulin resistance induced by high-fat feeding, but insulin clearance was not further deteriorated in the high-fat-fed Cc1−/− mice. In conclusion, our data indicate that CC1 is a key regulator of hepatic lipogenesis and that Cc1−/− mice are predisposed to liver steatosis, leading to hepatic insulin resistance and liver damage, particularly when chronically exposed to dietary fat.

scholarly journals The role of metabolic syndrome in Alzheimer’s disease

2021 ◽  
Author(s):  
Gláucia Maria Senhorinha ◽  
Arlys Emanuel Mendes da Silva Santos ◽  
Douglas Daniel Dophine
Keyword(s):  
Oxidative Stress ◽  
Alzheimer’S Disease ◽  
Insulin Resistance ◽  
Alzheimer's Disease ◽  
Metabolic Syndrome ◽  
Brain Regions ◽  
Alzheimer Dementia ◽  
The Metabolic Syndrome ◽  
The Brain

Background: Metabolic syndrome (MS) leads to the deposits formation of insoluble protein aggregates, neuroinflammation, oxidative stress, neuronal insulin resistance, progressive insulin resistance, desensitization and β-amyloid amyloidosis in the brain, besides direct ischemic effects which are closely associated with Alzheimer’s disease (AD).1 Objectives: The present study seeks to understand the role of the metabolic syndrome in the pathophysiology of Alzheimer’s disease and to describe preventive and therapeutic interventions. Methods: PUBMED and Web of Science were the databases used, the following descriptors were used to search the articles: “Alzheimer Disease” OR “Alzheimer Dementia” AND “Metabolic Syndrome”. Results: The studies in general have shown that MS is related to AD through brain insulin resistance, triggered by oxidative stress and neuroinflammation. It is related to the progressive atrophy of brain regions involved in the progression of AD. Insulin resistance in the brain is related to the progressive atrophy of the brain regions from initial progression of AD. These regions are cingulate cortices, medial temporal lobe, prefrontal gyri and other regions.³ Thus, there is an inhibition of the mechanisms of beta-amyloid removal, leading to its accumulation, which generates neuroinflammation, that in turn potentiates insulin resistance in the central nervous system, contributing to the genesis and progression of cognitive damage.2,3 Conclusions: Insulin resistance plays a major role in the initiation and perpetuation of cognitive impairment in AD. Furthermore, the components of the MS associated with AD, when treated with preventive and therapeutic measures, break this association by promoting rebalancing of the metabolism.

scholarly journals Inflammation as a Link between Obesity and Metabolic Syndrome

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Faloia Emanuela ◽  
Michetti Grazia ◽  
De Robertis Marco ◽  
Luconi Maria Paola ◽  
Furlani Giorgio ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Metabolic Syndrome ◽  
Visceral Obesity ◽  
Low Grade ◽  
Subsequent Increase ◽  
The Metabolic Syndrome ◽  
Increased Risk ◽  
Inflammatory State

The metabolic syndrome is a complex of clinical features leading to an increased risk for cardiovascular disease and type 2 diabetes mellitus in both sexes. Visceral obesity and insulin resistance are considered the main features determining the negative cardiovascular profile in metabolic syndrome. The aim of this paper is to highlight the central role of obesity in the development of a chronic low-grade inflammatory state that leads to insulin resistance, endothelial and microvascular dysfunctions. It is thought that the starting signal of this inflammation is overfeeding and the pathway origins in all the metabolic cells; the subsequent increase in cytokine production recruits immune cells in the extracellular environment inducing an overall systemic inflammation. This paper focuses on the molecular and cellular inflammatory mechanisms studied until now.

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 Inflammatory Mediators and Insulin Resistance in Obesity: Role of Nuclear Receptor Signaling in Macrophages

2010 ◽  
Vol 2010 ◽  
pp. 1-10 ◽  
Author(s):  
Lucía Fuentes ◽  
Tamás Rőszer ◽  
Mercedes Ricote
Keyword(s):  
Insulin Resistance ◽  
Nuclear Receptor ◽  
Cytokine Production ◽  
Current Knowledge ◽  
Liver Steatosis ◽  
Visceral Obesity ◽  
M2 Macrophage ◽  
Low Grade ◽  
The Impact

Visceral obesity is coupled to a general low-grade chronic inflammatory state characterized by macrophage activation and inflammatory cytokine production, leading to insulin resistance (IR). The balance between proinflammatory M1 and antiinflammatory M2 macrophage phenotypes within visceral adipose tissue appears to be crucially involved in the development of obesity-associated IR and consequent metabolic abnormalities. The ligand-dependent transcription factors peroxisome proliferator activated receptors (PPARs) have recently been implicated in the determination of the M1/M2 phenotype. Liver X receptors (LXRs), which form another subgroup of the nuclear receptor superfamily, are also important regulators of proinflammatory cytokine production in macrophages. Disregulation of macrophage-mediated inflammation by PPARs and LXRs therefore underlies the development of IR. This review summarizes the role of PPAR and LXR signaling in macrophages and current knowledge about the impact of these actions in the manifestation of IR and obesity comorbidities such as liver steatosis and diabetic osteopenia.

scholarly journals Role of Ventromedial Hypothalamus in Sucrose-Induced Obesity on Metabolic Parameters

2021 ◽  
pp. 097275312110057
Author(s):  
Archana Gaur ◽  
G.K. Pal ◽  
Pravati Pal
Keyword(s):  
Insulin Resistance ◽  
Weight Gain ◽  
Food Intake ◽  
Ventromedial Hypothalamus ◽  
Female Rats ◽  
Metabolic Parameters ◽  
Male Rats ◽  
Significant Weight Gain ◽  
The Metabolic Syndrome

Background: Obesity is because of excessive fat accumulation that affects health adversely in the form of various diseases such as diabetes, hypertension, cardiovascular diseases, and many other disorders. Our Indian diet is rich in carbohydrates, and hence the sucrose-induced obesity is an apt model to mimic this. Ventromedial hypothalamus (VMH) is linked to the regulation of food intake in animals as well as humans. Purpose: To understand the role of VMHin sucrose-induced obesity on metabolic parameters. Methods: A total of 24 adult rats were made obese by feeding them on a 32% sucrose solution for 10 weeks. The VMH nucleus was ablated in the experimental group and sham lesions were made in the control group. Food intake, body weight, and biochemical parameters were compared before and after the lesion. Results: Male rats had a significant weight gain along with hyperphagia, whereas female rats did not have a significant weight gain inspite of hyperphagia. Insulin resistance and dyslipidemia were seen in both the experimental and control groups. Conclusion: A sucrose diet produces obesity which is similar to the metabolic syndrome with insulin resistance and dyslipidemia, and a VMH lesion further exaggerates it. Males are more prone to this exaggeration.

scholarly journals Effects of Caloric Restriction on Cardiac Oxidative Stress and Mitochondrial Bioenergetics: Potential Role of Cardiac Sirtuins

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Ken Shinmura
Keyword(s):  
Oxidative Stress ◽  
Free Radical ◽  
Oxidative Damage ◽  
Caloric Restriction ◽  
Functional Decline ◽  
Cellular Damage ◽  
Free Radical Theory ◽  
Radical Theory ◽  
Stress Theory

The biology of aging has not been fully clarified, but the free radical theory of aging is one of the strongest aging theories proposed to date. The free radical theory has been expanded to the oxidative stress theory, in which mitochondria play a central role in the development of the aging process because of their critical roles in bioenergetics, oxidant production, and regulation of cell death. A decline in cardiac mitochondrial function associated with the accumulation of oxidative damage might be responsible, at least in part, for the decline in cardiac performance with age. In contrast, lifelong caloric restriction can attenuate functional decline with age, delay the onset of morbidity, and extend lifespan in various species. The effect of caloric restriction appears to be related to a reduction in cellular damage induced by reactive oxygen species. There is increasing evidence that sirtuins play an essential role in the reduction of mitochondrial oxidative stress during caloric restriction. We speculate that cardiac sirtuins attenuate the accumulation of oxidative damage associated with age by modifying specific mitochondrial proteins posttranscriptionally. Therefore, the distinct role of each sirtuin in the heart subjected to caloric restriction should be clarified to translate sirtuin biology into clinical practice.

scholarly journals Duration of rise in free fatty acids determines salicylate's effect on hepatic insulin sensitivity

2013 ◽  
Vol 217 (1) ◽  
pp. 31-43 ◽  
Author(s):  
Sandra Pereira ◽  
Wen Qin Yu ◽  
María E Frigolet ◽  
Jacqueline L Beaudry ◽  
Yaniv Shpilberg ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Insulin Sensitivity ◽  
Muscle Protein ◽  
Hepatic Insulin Resistance ◽  
Skeletal Muscle Protein ◽  
Protein Levels ◽  
Peripheral Insulin Resistance ◽  
Plasma Ffa ◽  
A Site

We have shown in rats that sodium salicylate (SS), which inhibits IkBa kinase B (IKKB), prevents hepatic and peripheral insulin resistance caused by short-term (7 h) i.v. administration of Intralipid and heparin (IH). We wished to further determine whether this beneficial effect of SS persisted after prolonged (48 h) IH infusion, which better mimics the chronic free fatty acid (FFA) elevation of obesity. Hence, we performed hyperinsulinemic euglycemic clamps with tritiated glucose methodology to determine hepatic and peripheral insulin sensitivity in rats infused with saline, IH, IH and SS, or SS alone. SS prevented peripheral insulin resistance (P<0.05) caused by prolonged plasma FFA elevation; however, it did not prevent hepatic insulin resistance. In skeletal muscle, protein levels of phospho-IkBa were augmented by prolonged IH administration and this was prevented by SS, suggesting that IH activates while SS prevents the activation of IKKB. Markers of IKKB activation, namely protein levels of phospho-IkBa and IkBa, indicated that IKKB is not activated in the liver after prolonged FFA elevation. Phosphorylation of serine 307 at insulin receptor substrate (IRS)-1, which is a marker of proximal insulin resistance, was not altered by IH administration in the liver, suggesting that this is not a site of hepatic insulin resistance in the prolonged lipid infusion model. Our results suggest that the role of IKKB in fat-induced insulin resistance is time and tissue dependent and that hepatic insulin resistance induced by prolonged lipid elevation is not due to an IRS-1 serine 307 kinase.

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