B Lymphocytes and Adipose Tissue Inflammation

The immune system plays an important role in obesity-induced adipose tissue inflammation and the resultant metabolic dysfunction, which can lead to hypertension, dyslipidemia, and insulin resistance and their downstream sequelae of type 2 diabetes mellitus and cardiovascular disease. While macrophages are the most abundant immune cell type in adipose tissue, other immune cells are also present, such as B cells, which play important roles in regulating adipose tissue inflammation. This brief review will overview B-cell subsets, describe their localization in various adipose depots and summarize our knowledge about the function of these B-cell subsets in regulating adipose tissue inflammation, obesity-induced metabolic dysfunction and atherosclerosis.

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Adipose tissue inflammation and metabolic dysfunction: a clinical perspective

Hormone Molecular Biology and Clinical Investigation ◽

10.1515/hmbci-2013-0032 ◽

2013 ◽

Vol 15 (1) ◽

Cited By ~ 2

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).

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Innate Immune Cells in the Adipose Tissue in Health and Metabolic Disease

Journal of Innate Immunity ◽

10.1159/000515117 ◽

2021 ◽

pp. 1-27

Author(s):

Zoi Michailidou ◽

Mario Gomez-Salazar ◽

Vasileia Ismini Alexaki

Keyword(s):

Adipose Tissue ◽

Immune Cells ◽

Innate Immune ◽

Low Grade ◽

Innate Immune Cells ◽

Cellular Interactions ◽

Adipose Tissue Inflammation ◽

Tissue Inflammation

Metabolic disorders, such as obesity, type 2 diabetes mellitus, and nonalcoholic fatty liver disease, are characterized by chronic low-grade tissue and systemic inflammation. During obesity, the adipose tissue undergoes immunometabolic and functional transformation. Adipose tissue inflammation is driven by innate and adaptive immune cells and instigates insulin resistance. Here, we discuss the role of innate immune cells, that is, macrophages, neutrophils, eosinophils, natural killer cells, innate lymphoid type 2 cells, dendritic cells, and mast cells, in the adipose tissue in the healthy (lean) and diseased (obese) state and describe how their function is shaped by the obesogenic microenvironment, and humoral, paracrine, and cellular interactions. Moreover, we particularly outline the role of hypoxia as a central regulator in adipose tissue inflammation. Finally, we discuss the long-lasting effects of adipose tissue inflammation and its potential reversibility through drugs, caloric restriction, or exercise training.

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Progression from High Insulin Resistance to Type 2 Diabetes Does Not Entail Additional Visceral Adipose Tissue Inflammation

PLoS ONE ◽

10.1371/journal.pone.0048155 ◽

2012 ◽

Vol 7 (10) ◽

pp. e48155 ◽

Cited By ~ 22

Author(s):

Nuria Barbarroja ◽

Chary Lopez-Pedrera ◽

Lourdes Garrido-Sanchez ◽

Maria Dolores Mayas ◽

Wilfredo Oliva-Olivera ◽

...

Keyword(s):

Insulin Resistance ◽

Type 2 Diabetes ◽

Adipose Tissue ◽

Visceral Adipose Tissue ◽

Adipose Tissue Inflammation ◽

Tissue Inflammation ◽

High Insulin ◽

Visceral Adipose

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Adipose tissue inflammation: Feeding the development of type 2 diabetes mellitus

Immunobiology ◽

10.1016/j.imbio.2013.05.002 ◽

2013 ◽

Vol 218 (12) ◽

pp. 1497-1504 ◽

Cited By ~ 35

Author(s):

Victoria R. Richardson ◽

Kerrie A. Smith ◽

Angela M. Carter

Keyword(s):

Diabetes Mellitus ◽

Type 2 Diabetes ◽

Type 2 Diabetes Mellitus ◽

Adipose Tissue ◽

Adipose Tissue Inflammation ◽

Tissue Inflammation

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The Role of the Immune System in Obesity and Insulin Resistance

Journal of Obesity ◽

10.1155/2013/616193 ◽

2013 ◽

Vol 2013 ◽

pp. 1-9 ◽

Cited By ~ 68

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.

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Adipose tissue immune cells in obesity, type 2 diabetes mellitus and cardiovascular diseases

Journal of Endocrinology ◽

10.1530/joe-21-0159 ◽

2021 ◽

Author(s):

Anna Cinkajzlová ◽

Milos Mraz ◽

Martin Haluzik

Keyword(s):

Diabetes Mellitus ◽

Type 2 Diabetes ◽

Type 2 Diabetes Mellitus ◽

Adipose Tissue ◽

Cardiovascular Diseases ◽

Immune Cells ◽

Immune Cell ◽

Current Knowledge ◽

Systemic Circulation

Immune cells are an inseparable component of adipose tissue intimately involved in most of its functions. Physiologically, they regulate adipose tissue homeostasis, while in case of adipose tissue stress immune cells are able to change their phenotype, enhance their count and subsequently contribute to the development and maintenance of local adipose tissue inflammation. Immune cells are an important source of inflammatory cytokines and other pro-inflammatory products that further influence not only surrounding tissues, but via systemic circulation also the whole organism being thus one of the main factors responsible for the transition from simple obesity to associated metabolic and cardiovascular complications. The purpose of this review is to summarize current knowledge on different adipose tissue immune cell subsets and their role in the development of obesity, type 2 diabetes mellitus and cardiovascular diseases.

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