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Trends in Parasitology Sep 2015Parasitic helminths have coexisted with human beings throughout time. Success in eradicating helminths has limited helminth-induced morbidity and mortality but is also... (Review)
Review
Parasitic helminths have coexisted with human beings throughout time. Success in eradicating helminths has limited helminth-induced morbidity and mortality but is also correlated with increasing rates of 'western' diseases, including metabolic syndrome and type 2 diabetes. Recent studies in mice describe how type 2 immune cells, traditionally associated with helminth infection, maintain adipose tissue homeostasis and promote adipose tissue beiging, protecting against obesity and metabolic dysfunction. Here, we review these studies and discuss how helminths and helminth-derived molecules may modulate these physiologic pathways to improve metabolic functions in specific tissues, such as adipose and liver, as well as at the whole-organism level.
Topics: Adipose Tissue; Animals; Biological Evolution; Helminthiasis; Helminths; Host-Parasite Interactions; Metabolic Syndrome; Mice
PubMed: 25991556
DOI: 10.1016/j.pt.2015.04.008 -
Frontiers in Endocrinology 2021Brown and beige adipose tissues possess the remarkable capacity to convert energy into heat, which potentially opens novel therapeutic perspectives targeting the... (Review)
Review
Brown and beige adipose tissues possess the remarkable capacity to convert energy into heat, which potentially opens novel therapeutic perspectives targeting the epidemic of metabolic syndromes such as obesity and type 2 diabetes. These thermogenic fats implement mitochondrial oxidative phosphorylation and uncouple respiration to catabolize fatty acids and glucose, which leads to an increase in energy expenditure. In particular, beige adipocytes that arise in white adipose tissue display their thermogenic capacity through various noncanonical mechanisms. This review aims to summarize the general overview of thermogenic fat, especially including the UCP1-independent adaptive thermogenesis and the emerging mechanisms of "beiging", which may provide more evidence of targeting thermogenic fat to counteract obesity and other metabolic disorders in humans.
Topics: Adipocytes, Beige; Adipose Tissue; Adipose Tissue, Beige; Adipose Tissue, Brown; Adipose Tissue, White; Energy Metabolism; Humans; Lipid Metabolism; Lipolysis; Thermogenesis
PubMed: 34367068
DOI: 10.3389/fendo.2021.696505 -
Endocrinology and Metabolism Clinics of... Mar 2014Glucocorticoids (GCs) are critical in the regulation of the stress response, inflammation and energy homeostasis. Excessive GC exposure results in whole-body insulin... (Review)
Review
Glucocorticoids (GCs) are critical in the regulation of the stress response, inflammation and energy homeostasis. Excessive GC exposure results in whole-body insulin resistance, obesity, cardiovascular disease, and ultimately decreased survival, despite their potent anti-inflammatory effects. This apparent paradox may be explained by the complex actions of GCs on adipose tissue functionality. The wide prevalence of oral GC therapy makes their adverse systemic effects an important yet incompletely understood clinical problem. This article reviews the mechanisms by which supraphysiologic GC exposure promotes insulin resistance, focusing in particular on the effects on adipose tissue function and lipid metabolism.
Topics: Adipose Tissue; Glucocorticoids; Humans; Insulin Resistance; Lipid Metabolism
PubMed: 24582093
DOI: 10.1016/j.ecl.2013.10.005 -
Journal of Artificial Organs : the... Mar 2013Adipose tissue engineering for breast reconstruction can be performed for patients who have undergone breast surgery. We have previously confirmed adipogenesis in mice...
Adipose tissue engineering for breast reconstruction can be performed for patients who have undergone breast surgery. We have previously confirmed adipogenesis in mice implanted with type I collagen sponge with controlled release of fibroblast growth factor 2 (FGF2) and human adipose tissue-derived stem cells. However, in order to use this approach to treat breast cancer patients, a large amount of adipose tissue is needed, and FGF2 is not readily available. Thus, we aimed to regenerate large amounts of adipose tissue without FGF2 for a long period. Under general anesthesia, cages made of polypropylene mesh were implanted into the rabbits' bilateral fat pads. Each cage was 10 mm in radius and 10 mm in height. Minced type I collagen sponge was injected as a scaffold into the cage. Regenerated tissue in the cage was examined with ultrasonography, and the cages were harvested 3, 6, and 12 months after the implantation. Ultrasonography revealed a gradually increasing homogeneous high-echo area in the cage. Histology of the specimen was assessed with hematoxylin and eosin staining. The percentages of regenerated adipose tissue area were 76.2 ± 13.0 and 92.8 ± 6.6 % at 6 and 12 months after the implantation, respectively. Our results showed de novo adipogenesis 12 months after the implantation of only type I collagen sponge inside the space. Ultrasonography is a noninvasive and useful method of assessing the growth of the tissue inside the cage. This simple method could be a promising clinical modality in breast reconstruction.
Topics: Adipogenesis; Adipose Tissue; Animals; Cells, Cultured; Collagen Type I; Female; Rabbits; Tissue Engineering; Tissue Scaffolds
PubMed: 23114565
DOI: 10.1007/s10047-012-0670-4 -
World Journal of Gastroenterology Jul 2007Nonalcoholic fatty liver disease (NAFLD) is an increasingly recognized cause of liver-related morbidity and mortality. It can develop secondary to numerous causes but a... (Review)
Review
Nonalcoholic fatty liver disease (NAFLD) is an increasingly recognized cause of liver-related morbidity and mortality. It can develop secondary to numerous causes but a great majority of NAFLD cases occur in patients who are obese or present with other components of metabolic syndrome (hypertension, dyslipidemia, diabetes). This is called primary NAFLD and insulin resistance plays a key role in its pathogenesis. Obesity is characterized by expanded adipose tissue, which is under a state of chronic inflammation. This disturbs the normal storage and endocrine functions of adipose tissue. In obesity, the secretome (adipokines, cytokines, free fatty acids and other lipid moieties) of fatty tissue is amplified, which through its autocrine, paracrine actions in fat tissue and systemic effects especially in the liver leads to an altered metabolic state with insulin resistance (IR). IR leads to hyperglycemia and reactive hyperinsulinemia, which stimulates lipid-accumulating processes and impairs hepatic lipid metabolism. IR enhances free fatty acid delivery to liver from the adipose tissue storage due to uninhibited lipolysis. These changes result in hepatic abnormal fat accumulation, which may initiate the hepatic IR and further aggravate the altered metabolic state of whole body. Hepatic steatosis can also be explained by the fact that there is enhanced dietary fat delivery and physical inactivity. IR and NAFLD are also seen in various lipodystrophic states in contrary to popular belief that these problems only occur due to excessive adiposity in obesity. Hence, altered physiology of adipose tissue is central to development of IR, metabolic syndrome and NAFLD.
Topics: Adipose Tissue; Chronic Disease; Fatty Liver; Humans; Inflammation; Insulin Resistance; Life Style; Lipid Metabolism; Liver; Metabolic Syndrome; Obesity
PubMed: 17659704
DOI: 10.3748/wjg.v13.i26.3540 -
Bone Jan 2019Anorexia nervosa (AN) is a psychiatric disorder characterized by inappropriate nutrient intake resulting in low body weight. Multiple hormonal adaptations facilitate... (Review)
Review
Anorexia nervosa (AN) is a psychiatric disorder characterized by inappropriate nutrient intake resulting in low body weight. Multiple hormonal adaptations facilitate decreased energy expenditure in this state of caloric deprivation including non-thyroidal illness syndrome, growth hormone resistance, and hypogonadotropic hypogonadism. Although these hormonal adaptations confer a survival advantage during periods of negative energy balance, they contribute to the long-term medical complications associated with AN, the most common of which is significant bone loss and an increased risk of fracture. In recent years, marrow adipose tissue (MAT) has emerged as an important potential determinant of the low bone mass state characteristic of AN. Unlike subcutaneous and visceral adipose tissue depots which are low in AN, MAT levels are paradoxically elevated and are inversely associated with BMD. In this review, we discuss what is known about MAT in AN and the proposed hormonal determinants of this adipose tissue depot.
Topics: Adipose Tissue; Animals; Anorexia Nervosa; Body Composition; Bone Density; Bone Marrow; Humans
PubMed: 29458121
DOI: 10.1016/j.bone.2018.02.013 -
Diabetologia Jun 2016White adipose tissue (WAT) has key metabolic and endocrine functions and plays a role in regulating energy homeostasis and insulin sensitivity. WAT is characterised by... (Review)
Review
White adipose tissue (WAT) has key metabolic and endocrine functions and plays a role in regulating energy homeostasis and insulin sensitivity. WAT is characterised by its capacity to adapt and expand in response to surplus energy through processes of adipocyte hypertrophy and/or recruitment and proliferation of precursor cells in combination with vascular and extracellular matrix remodelling. However, in the context of sustained obesity, WAT undergoes fibro-inflammation, which compromises its functionality, contributing to increased risk of type 2 diabetes and cardiovascular diseases. Conversely, brown adipose tissue (BAT) and browning of WAT represent potential therapeutic approaches, since dysfunctional white adipocyte-induced lipid overspill can be halted by BAT/browning-mediated oxidative anti-lipotoxic effects. Better understanding of the cellular and molecular pathophysiological mechanisms regulating adipocyte size, number and depot-dependent expansion has become a focus of interest over recent decades. Here, we summarise the mechanisms contributing to adipose tissue (AT) plasticity and function including characteristics and cellular complexity of the various adipose depots and we discuss recent insights into AT origins, identification of adipose precursors, pathophysiological regulation of adipogenesis and its relation to WAT/BAT expandability in obesity and its associated comorbidities.
Topics: Adipogenesis; Adipose Tissue; Animals; Diabetes Mellitus, Type 2; Fibrosis; Humans; Obesity
PubMed: 27039901
DOI: 10.1007/s00125-016-3933-4 -
Arteriosclerosis, Thrombosis, and... Oct 2014Obesity is a worldwide epidemic and is associated with multiple comorbidities. The mechanisms underlying the relationship between obesity and adverse health outcomes... (Review)
Review
Obesity is a worldwide epidemic and is associated with multiple comorbidities. The mechanisms underlying the relationship between obesity and adverse health outcomes remain poorly understood. This may be because of several factors including the crude measures used to estimate adiposity, the striking heterogeneity between adipose tissue depots, and the influence of fat accumulation in multiple organs. To advance our understanding of fat stores and associated comorbidities in humans, it will be necessary to image adiposity throughout the body and ultimately also assess its functionality. Large clinical studies are demonstrating the prognostic importance of adipose tissue imaging. Newer techniques capable of imaging fat metabolism and other functions of adipose tissue may provide additional prognostic use and may be useful in guiding therapeutic interventions.
Topics: Absorptiometry, Photon; Adipose Tissue; Adiposity; Animals; Cardiovascular Diseases; Comorbidity; Diagnostic Imaging; Humans; Lipid Metabolism; Magnetic Resonance Imaging; Obesity; Positron-Emission Tomography; Predictive Value of Tests; Risk Factors; Tomography, X-Ray Computed; Ultrasonography; Whole Body Imaging
PubMed: 25147343
DOI: 10.1161/ATVBAHA.114.303036 -
The Biochemical Journal Feb 2020A central function of adipose tissue is in the management of systemic energy homeostasis that is achieved through the co-ordinated regulation of energy storage and... (Review)
Review
A central function of adipose tissue is in the management of systemic energy homeostasis that is achieved through the co-ordinated regulation of energy storage and mobilization, adipokine release, and immune functions. With the dramatic increase in the prevalence of obesity and obesity-related metabolic disease over the past 30 years, there has been extensive interest in targeting adipose tissue for therapeutic benefit. However, in order for this goal to be achieved it is essential to establish a comprehensive atlas of adipose tissue cellular composition and define mechanisms of intercellular communication that mediate pathologic and therapeutic responses. While traditional methods, such as fluorescence-activated cell sorting (FACS) and genetic lineage tracing, have greatly advanced the field, these approaches are inherently limited by the choice of markers and the ability to comprehensively identify and characterize dynamic interactions among stromal cells within the tissue microenvironment. Single cell RNA sequencing (scRNAseq) has emerged as a powerful tool for deconvolving cellular heterogeneity and holds promise for understanding the development and plasticity of adipose tissue under normal and pathological conditions. scRNAseq has recently been used to characterize adipose stem cell (ASC) populations and has provided new insights into subpopulations of macrophages that arise during anabolic and catabolic remodeling in white adipose tissue. The current review summarizes recent findings that use this technology to explore adipose tissue heterogeneity and plasticity.
Topics: Adipocytes; Adipose Tissue; Adipose Tissue, White; Animals; Cell Communication; Flow Cytometry; Humans; Macrophages; Obesity; Sequence Analysis, RNA; Single-Cell Analysis; Stromal Cells
PubMed: 32026949
DOI: 10.1042/BCJ20190467 -
Lipids in Health and Disease Jul 2020Obesity exhibits a correlation with metabolic inflammation and endoplasmic reticulum stress, promoting the progression of metabolic disease such as diabetes,... (Review)
Review
Obesity exhibits a correlation with metabolic inflammation and endoplasmic reticulum stress, promoting the progression of metabolic disease such as diabetes, hyperlipidemia, hyperuricemia and so on. Adipose tissue macrophages (ATMs) are central players in obesity-associated inflammation and metabolic diseases. Macrophages are involved in lipid and energy metabolism and mitochondrial function in adipocytes. Macrophage polarization is accompanied by metabolic shifting between glycolysis and mitochondrial oxidative phosphorylation. Here, this review focuses on macrophage metabolism linked to functional phenotypes with an emphasis on macrophage polarization in adipose tissue physiological and pathophysiological processes. In particular, the interplay between ATMs and adipocytes in energy metabolism, glycolysis, OXPHOS, iron handing and even interactions with the nervous system have been reviewed. Overall, the understanding of protective and pathogenic roles of ATMs in adipose tissue can potentially provide strategies to prevent and treat obesity-related metabolic disorders.
Topics: Adipocytes; Adipose Tissue; Animals; Energy Metabolism; Glycolysis; Humans; Iron; Macrophages; Oxidative Phosphorylation
PubMed: 32646451
DOI: 10.1186/s12944-020-01342-3