scholarly journals The Role of the Immune System in Obesity and Insulin Resistance

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Payal S. Patel ◽  
Eric D. Buras ◽  
Ashok Balasubramanyam
Keyword(s):  
Insulin Resistance ◽  
Adipose Tissue ◽  
Immune System ◽  
Stress Responses ◽  
Innate Immune System ◽  
Metabolic Diseases ◽  
Innate Immune ◽  
Metabolic Dysfunction ◽  
Adipose Tissue Inflammation ◽  
Tissue Inflammation

The innate immune system provides organisms with rapid and well-coordinated protection from foreign pathogens. However, under certain conditions of metabolic dysfunction, components of the innate immune system may be activated in the absence of external pathogens, leading to pathologic consequences. Indeed, there appears to be an intimate relationship between metabolic diseases and immune dysfunction; for example, macrophages are prime players in the initiation of a chronic inflammatory state in obesity which leads to insulin resistance. In response to increases in free fatty acid release from obese adipose depots, M1-polarized macrophages infiltrate adipose tissues. These M1 macrophages trigger inflammatory signaling and stress responses within cells that signal through JNK or IKKβpathways, leading to insulin resistance. If overnutrition persists, mechanisms that counteract inflammation (such as M2 macrophages and PPAR signaling) are suppressed, and the inflammation becomes chronic. Although macrophages are a principal constituent of obese adipose tissue inflammation, other components of the immune system such as lymphocytes and mast cells also contribute to the inflammatory cascade. Thus it is not merely an increased mass of adipose tissue that directly leads to attenuation of insulin action, but rather adipose tissue inflammation activated by the immune system in obese individuals that leads to insulin resistance.

scholarly journals Adipose tissue inflammation and metabolic dysfunction: a clinical perspective

2013 ◽  
Vol 15 (1) ◽  
Author(s):  
Charmaine S. Tam ◽  
Leanne M. Redman
Keyword(s):  
Insulin Resistance ◽  
Adipose Tissue ◽  
Low Grade ◽  
Metabolic Dysfunction ◽  
Adipose Tissue Inflammation ◽  
Tissue Inflammation ◽  
Proinflammatory Mediators ◽  
Low Grade Inflammation

AbstractObesity is characterized by a state of chronic low-grade inflammation due to increased immune cells, specifically infiltrated macrophages into adipose tissue, which in turn secrete a range of proinflammatory mediators. This nonselective low-grade inflammation of adipose tissue is systemic in nature and can impair insulin signaling pathways, thus, increasing the risk of developing insulin resistance and type 2 diabetes. The aim of this review is to provide an update on clinical studies examining the role of adipose tissue in the development of obesity-associated complications in humans. We will discuss adipose tissue inflammation during different scenarios of energy imbalance and metabolic dysfunction including obesity and overfeeding, weight loss by calorie restriction or bariatric surgery, and conditions of insulin resistance (diabetes, polycystic ovarian syndrome).

scholarly journals CREB pathway links PGE2 signaling with macrophage polarization

2015 ◽  
Vol 112 (51) ◽  
pp. 15642-15647 ◽  
Author(s):  
Bing Luan ◽  
Young-Sil Yoon ◽  
John Le Lay ◽  
Klaus H. Kaestner ◽  
Susan Hedrick ◽  
...  
Keyword(s):  
Gene Expression ◽  
Insulin Resistance ◽  
Adipose Tissue ◽  
Immune System ◽  
Insulin Sensitivity ◽  
Innate Immune System ◽  
Marker Gene ◽  
Innate Immune ◽  
M2 Polarization ◽  
Marker Gene Expression

Obesity is thought to promote insulin resistance in part via activation of the innate immune system. Increases in proinflammatory cytokine production by M1 macrophages inhibit insulin signaling in white adipose tissue. In contrast, M2 macrophages have been found to enhance insulin sensitivity in part by reducing adipose tissue inflammation. The paracrine hormone prostaglandin E2 (PGE2) enhances M2 polarization in part through activation of the cAMP pathway, although the underlying mechanism is unclear. Here we show that PGE2 stimulates M2 polarization via the cyclic AMP-responsive element binding (CREB)-mediated induction of Krupple-like factor 4 (KLF4). Targeted disruption of CREB or the cAMP-regulated transcriptional coactivators 2 and 3 (CRTC2/3) in macrophages down-regulated M2 marker gene expression and promoted insulin resistance in the context of high-fat diet feeding. As re-expression of KLF4 rescued M2 marker gene expression in CREB-depleted cells, our results demonstrate the importance of the CREB/CRTC pathway in maintaining insulin sensitivity in white adipose tissue via its effects on the innate immune system.

Adipose tissue inflammation: a cause or consequence of obesity-related insulin resistance?

2016 ◽  
Vol 130 (18) ◽  
pp. 1603-1614 ◽  
Author(s):  
Matthias Blüher
Keyword(s):  
Insulin Resistance ◽  
Adipose Tissue ◽  
Chronic Inflammation ◽  
Metabolic Diseases ◽  
Health Concern ◽  
Noncommunicable Diseases ◽  
Adipose Tissue Inflammation ◽  
Tissue Storage ◽  
Tissue Inflammation ◽  
Increased Risk

The worldwide obesity epidemic has become a major health concern, because it contributes to higher mortality due to an increased risk for noncommunicable diseases including cardiovascular diseases, type 2 diabetes, musculoskeletal disorders and some cancers. Insulin resistance may link accumulation of adipose tissue in obesity to metabolic diseases, although the underlying mechanisms are not completely understood. In the past decades, data from human studies and transgenic animal models strongly suggested correlative, but also causative associations between activation of proinflammatory pathways and insulin resistance. Particularly chronic inflammation in adipose tissue seems to play an important role in the development of obesity-related insulin resistance. On the other hand, adipose tissue inflammation has been shown to be essential for healthy adipose tissue expansion and remodelling. However, whether adipose tissue inflammation represents a consequence or a cause of impaired insulin sensitivity remains an open question. A better understanding of the molecular pathways linking excess adipose tissue storage to chronic inflammation and insulin resistance may provide the basis for the future development of anti-inflammatory treatment strategies to improve adverse metabolic consequences of obesity. In this review, potential mechanisms of adipose tissue inflammation and how adipose tissue inflammation may cause insulin resistance are discussed.

Flavonoids in adipose tissue inflammation and atherosclerosis: one arrow, two targets

2020 ◽  
Vol 134 (12) ◽  
pp. 1403-1432 ◽  
Author(s):  
Manal Muin Fardoun ◽  
Dina Maaliki ◽  
Nabil Halabi ◽  
Rabah Iratni ◽  
Alessandra Bitto ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Fruits And Vegetables ◽  
Metabolic Diseases ◽  
Therapeutic Agents ◽  
Adipose Tissue Inflammation ◽  
Cellular Mechanisms ◽  
Tissue Inflammation ◽  
Cholesterol Levels ◽  
Naturally Occurring ◽  
Pro Inflammatory Cytokines

Abstract Flavonoids are polyphenolic compounds naturally occurring in fruits and vegetables, in addition to beverages such as tea and coffee. Flavonoids are emerging as potent therapeutic agents for cardiovascular as well as metabolic diseases. Several studies corroborated an inverse relationship between flavonoid consumption and cardiovascular disease (CVD) or adipose tissue inflammation (ATI). Flavonoids exert their anti-atherogenic effects by increasing nitric oxide (NO), reducing reactive oxygen species (ROS), and decreasing pro-inflammatory cytokines. In addition, flavonoids alleviate ATI by decreasing triglyceride and cholesterol levels, as well as by attenuating inflammatory mediators. Furthermore, flavonoids inhibit synthesis of fatty acids and promote their oxidation. In this review, we discuss the effect of the main classes of flavonoids, namely flavones, flavonols, flavanols, flavanones, anthocyanins, and isoflavones, on atherosclerosis and ATI. In addition, we dissect the underlying molecular and cellular mechanisms of action for these flavonoids. We conclude by supporting the potential benefit for flavonoids in the management or treatment of CVD; yet, we call for more robust clinical studies for safety and pharmacokinetic values.

scholarly journals IL-1 family members in the pathogenesis and treatment of metabolic disease: Focus on adipose tissue inflammation and insulin resistance

Cytokine ◽  
2015 ◽  
Vol 75 (2) ◽  
pp. 280-290 ◽  
Author(s):  
Dov B. Ballak ◽  
Rinke Stienstra ◽  
Cees J. Tack ◽  
Charles A. Dinarello ◽  
Janna A. van Diepen
Keyword(s):  
Metabolic Disease ◽  
Insulin Resistance ◽  
Adipose Tissue ◽  
Family Members ◽  
Adipose Tissue Inflammation ◽  
Tissue Inflammation ◽  
Disease Focus

scholarly journals Glucose-6-Phosphate Dehydrogenase Deficiency Improves Insulin Resistance With Reduced Adipose Tissue Inflammation in Obesity

Diabetes ◽  
2016 ◽  
Vol 65 (9) ◽  
pp. 2624-2638 ◽  
Author(s):  
Mira Ham ◽  
Sung Sik Choe ◽  
Kyung Cheul Shin ◽  
Goun Choi ◽  
Ji-Won Kim ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Adipose Tissue ◽  
Dehydrogenase Deficiency ◽  
Adipose Tissue Inflammation ◽  
Tissue Inflammation ◽  
Glucose 6 Phosphate Dehydrogenase

scholarly journals Macrophage VLDLR mediates obesity-induced insulin resistance with adipose tissue inflammation

2017 ◽  
Vol 8 (1) ◽  
Author(s):  
Kyung Cheul Shin ◽  
Injae Hwang ◽  
Sung Sik Choe ◽  
Jeu Park ◽  
Yul Ji ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Adipose Tissue ◽  
Adipose Tissue Inflammation ◽  
Tissue Inflammation
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