scholarly journals Obesity, insulin resistance and comorbidities ? Mechanisms of association

2014 ◽  
Vol 58 (6) ◽  
pp. 600-609 ◽  
Author(s):  
Ana Valeria B. Castro ◽  
Cathryn M. Kolka ◽  
Stella P. Kim ◽  
Richard N. Bergman
Keyword(s):  
Insulin Resistance ◽  
Adipose Tissue ◽  
Molecular Mechanisms ◽  
Metabolic Diseases ◽  
Polycystic Ovary ◽  
Bone Fragility ◽  
The Body ◽  
Ectopic Fat ◽  
Increased Risk ◽  
Fat Liver

Overall excess of fat, usually defined by the body mass index, is associated with metabolic (e.g. glucose intolerance, type 2 diabetes mellitus (T2DM), dyslipidemia) and non-metabolic disorders (e.g. neoplasias, polycystic ovary syndrome, non-alcoholic fat liver disease, glomerulopathy, bone fragility etc.). However, more than its total amount, the distribution of adipose tissue throughout the body is a better predictor of the risk to the development of those disorders. Fat accumulation in the abdominal area and in non-adipose tissue (ectopic fat), for example, is associated with increased risk to develop metabolic and non-metabolic derangements. On the other hand, observations suggest that individuals who present peripheral adiposity, characterized by large hip and thigh circumferences, have better glucose tolerance, reduced incidence of T2DM and of metabolic syndrome. Insulin resistance (IR) is one of the main culprits in the association between obesity, particularly visceral, and metabolic as well as non-metabolic diseases. In this review we will highlight the current pathophysiological and molecular mechanisms possibly involved in the link between increased VAT, ectopic fat, IR and comorbidities. We will also provide some insights in the identification of these abnormalities. Arq Bras Endocrinol Metab. 2014;58(6):600-9

scholarly journals Insulin-stimulated adiponectin secretion in pregnancy is mediated by inhibition of adiponectin ubiquitination and degradation and is impaired in obesity

2021 ◽  
Author(s):  
Irving L. M. H. Aye ◽  
Fredrick J. Rosario ◽  
Anita Kramer ◽  
Oddrun Kristiansen ◽  
Trond M. Michelsen ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Adipose Tissue ◽  
Gestational Diabetes ◽  
Er Stress ◽  
Pregnant Women ◽  
Fetal Growth ◽  
Molecular Mechanisms ◽  
Placental Function ◽  
Increased Risk ◽  
In Pregnancy

ABSTRACTIn pregnancy, adiponectin serves as an endocrine link between maternal adipose tissue, placental function and fetal growth, with low adiponectin promoting placental function and fetal growth. Circulating adiponectin levels are decreased in obese pregnant women and in gestational diabetes, which is believed to contribute to the insulin resistance and increased risk of fetal overgrowth associated with these conditions. However, the molecular mechanisms governing adiponectin secretion from maternal adipose tissues in pregnancy are poorly understood. Using visceral adipose tissue from lean and obese pregnant mice, we show that obesity in pregnancy is associated with adipose tissue inflammation, ER stress, insulin resistance, increased adiponectin ubiquitination and decreased total abundance of adiponectin. Moreover, adiponectin ubiquitination was increased in visceral fat of obese pregnant women as compared to lean pregnant women. We further observed that insulin prevents, whereas ER stress and inflammation promote, adiponectin ubiquitination and degradation in differentiated 3T3-L1 adipocytes. We have identified key molecular pathways regulating adiponectin secretion in pregnancy. This information will help us better understand the mechanisms controlling maternal insulin resistance and fetal growth in pregnancy and may provide a foundation for the development of strategies aimed at improving adiponectin production in pregnant women with obesity or gestational diabetes.

scholarly journals Recent Update on the Molecular Mechanisms of Gonadal Steroids Action in Adipose Tissue

2021 ◽  
Vol 22 (10) ◽  
pp. 5226
Author(s):  
Agata Wawrzkiewicz-Jałowiecka ◽  
Anna Lalik ◽  
Graça Soveral
Keyword(s):  
Adipose Tissue ◽  
Drug Targets ◽  
Molecular Mechanisms ◽  
Metabolic Diseases ◽  
Polycystic Ovary ◽  
Fatty Acid Uptake ◽  
Gonadal Steroids ◽  
Acid Uptake ◽  
Metabolic Disturbances ◽  
Fat Depots

The gonadal steroids, including androgens, estrogens and progestogens, are involved in the control of body fat distribution in humans. Nevertheless, not only the size and localization of the fat depots depend on the sex steroids levels, but they can also highly affect the functioning of adipose tissue. Namely, the gonadocorticoids can directly influence insulin signaling, lipid metabolism, fatty acid uptake and adipokine production. They may also alter energy balance and glucose homeostasis in adipocytes in an indirect way, e.g., by changing the expression level of aquaglyceroporins. This work presents the recent advances in understanding the molecular mechanism of how the gonadal steroids influence the functioning of adipose tissue leading to a set of detrimental metabolic consequences. Special attention is given here to highlighting the sexual dimorphism of adipocyte functioning in terms of health and disease. Particularly, we discuss the molecular background of metabolic disturbances occurring in consequence of hormonal imbalance which is characteristic of some common endocrinopathies such as the polycystic ovary syndrome. From this perspective, we highlight the potential drug targets and the active substances which can be used in personalized sex-specific management of metabolic diseases, in accord with the patient’s hormonal status.

scholarly journals DNA Methylation as a Marker of Body Shape in Premenopausal Women

2021 ◽  
Vol 12 ◽  
Author(s):  
Adeline Divoux ◽  
Alexey Eroshkin ◽  
Edina Erdos ◽  
Katalin Sandor ◽  
Timothy F. Osborne ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Adipose Tissue ◽  
Body Fat ◽  
Body Shape ◽  
Metabolic Diseases ◽  
Premenopausal Women ◽  
Fat Distribution ◽  
The Body ◽  
Fat Depots ◽  
Increased Risk

Preferential accumulation of fat in the gluteo-femoral (GF) depot (pear shape) rather than in the abdominal (A) depot (apple shape), protects against the development of metabolic diseases but the underlying molecular mechanism is still unknown. Recent data, including our work, suggest that differential epigenetic marking is associated with regulation of genes attributed to distinct fat distribution. Here, we aimed to compare the genomic DNA methylation signatures between apple and pear-shaped premenopausal women. To investigate the contribution of upper and lower body fat, we used paired samples of A-FAT and GF-FAT, analyzed on the BeadChip Methylation Array and quantified the differentially methylated sites between the 2 groups of women. We found unique DNA methylation patterns within both fat depots that are significantly different depending on the body fat distribution. Around 60% of the body shape specific DNA methylation sites identified in adipose tissue are maintained ex vivo in cultured preadipocytes. As it has been reported before in other cell types, we found only a hand full of genes showing coordinated differential methylation and expression levels. Finally, we determined that more than 50% of the body shape specific DNA methylation sites could also be detected in whole blood derived DNA. These data reveal a strong DNA methylation program associated with adipose tissue distribution with the possibility that a simple blood test could be used as a predictive diagnostic indicator of young women who are at increased risk for progressing to the apple body shape with a higher risk of developing obesity related complications.Clinical Trial Registration:https://clinicaltrials.gov/ct2/show/NCT02728635 and https://clinicaltrials.gov/ct2/show/NCT02226640, identifiers NCT02728635 and NCT02226640.

scholarly journals Tofogliflozin Improves Insulin Resistance in Skeletal Muscle and Accelerates Lipolysis in Adipose Tissue in Male Mice

Endocrinology ◽  
2015 ◽  
Vol 157 (3) ◽  
pp. 1029-1042 ◽  
Author(s):  
Atsushi Obata ◽  
Naoto Kubota ◽  
Tetsuya Kubota ◽  
Masahiko Iwamoto ◽  
Hiroyuki Sato ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Skeletal Muscle ◽  
Adipose Tissue ◽  
Glucose Uptake ◽  
White Adipose Tissue ◽  
High Fat Diet ◽  
Molecular Mechanisms ◽  
The Body ◽  
High Fat ◽  
Ad Libitum

Abstract Sodium glucose cotransporter 2 inhibitors have attracted attention as they exert antidiabetic and antiobesity effects. In this study, we investigated the effects of tofogliflozin on glucose homeostasis and its metabolic consequences and clarified the underlying molecular mechanisms. C57BL/6 mice were fed normal chow containing tofogliflozin (0.005%) for 20 weeks or a high-fat diet containing tofogliflozin (0.005%) for 8 weeks ad libitum. In addition, the animals were pair-fed in relation to controls to exclude the influence of increased food intake. Tofogliflozin reduced the body weight gain, mainly because of fat mass reduction associated with a diminished adipocyte size. Glucose tolerance and insulin sensitivity were ameliorated. The serum levels of nonesterified fatty acid and ketone bodies were increased and the respiratory quotient was decreased in the tofogliflozin-treated mice, suggesting the acceleration of lipolysis in the white adipose tissue and hepatic β-oxidation. In fact, the phosphorylation of hormone-sensitive lipase and the adipose triglyceride lipase protein levels in the white adipose tissue as well as the gene expressions related to β-oxidation, such as Cpt1α in the liver, were significantly increased. The hepatic triglyceride contents and the expression levels of lipogenic genes were decreased. Pair-fed mice exhibited almost the same results as mice fed an high-fat diet ad libitum. Moreover, a hyperinsulinemic-euglycemic clamp revealed that tofogliflozin improved insulin resistance by increasing glucose uptake, especially in the skeletal muscle, in pair-fed mice. Taken together, these results suggest tofogliflozin ameliorates insulin resistance and obesity by increasing glucose uptake in skeletal muscle and lipolysis in adipose tissue.

scholarly journals Molecular Insulin Actions Are Sexually Dimorphic in Lipid Metabolism

2021 ◽  
Vol 12 ◽  
Author(s):  
Rosa Isela Ortiz-Huidobro ◽  
Myrian Velasco ◽  
Carlos Larqué ◽  
Rene Escalona ◽  
Marcia Hiriart
Keyword(s):  
Insulin Resistance ◽  
Adipose Tissue ◽  
Sexual Dimorphism ◽  
Energy Homeostasis ◽  
Molecular Mechanisms ◽  
Metabolic Diseases ◽  
Critical Role ◽  
Metabolic Dysfunction ◽  
Anabolic Hormone ◽  
Obesity And Diabetes

The increment in energy-dense food and low physical activity has contributed to the current obesity pandemic, which is more prevalent in women than in men. Insulin is an anabolic hormone that regulates the metabolism of lipids, carbohydrates, and proteins in adipose tissue, liver, and skeletal muscle. During obesity, nutrient storage capacity is dysregulated due to a reduced insulin action on its target organs, producing insulin resistance, an early marker of metabolic dysfunction. Insulin resistance in adipose tissue is central in metabolic diseases due to the critical role that this tissue plays in energy homeostasis. We focused on sexual dimorphism on the molecular mechanisms of insulin actions and their relationship with the physiology and pathophysiology of adipose tissue. Until recently, most of the physiological and pharmacological studies were done in males without considering sexual dimorphism, which is relevant. There is ample clinical and epidemiological evidence of its contribution to the establishment and progression of metabolic diseases. Sexual dimorphism is a critical and often overlooked factor that should be considered in design of sex-targeted therapeutic strategies and public health policies to address obesity and diabetes.

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.

Metabolic Syndrome During Menopause

2019 ◽  
Vol 17 (6) ◽  
pp. 595-603 ◽  
Author(s):  
Sezcan Mumusoglu ◽  
Bulent Okan Yildiz
Keyword(s):  
Insulin Resistance ◽  
Metabolic Syndrome ◽  
Central Obesity ◽  
Polycystic Ovary ◽  
Ovary Syndrome ◽  
Natural Menopause ◽  
The Metabolic Syndrome ◽  
Increased Risk ◽  
Aging Women

The metabolic syndrome (MetS) comprises individual components including central obesity, insulin resistance, dyslipidaemia and hypertension and it is associated with an increased risk of cardiovascular disease (CVD) and type 2 diabetes mellitus (T2DM). The menopause per se increases the incidence of MetS in aging women. The effect(s) of menopause on individual components of MetS include: i) increasing central obesity with changes in the fat tissue distribution, ii) potential increase in insulin resistance, iii) changes in serum lipid concentrations, which seem to be associated with increasing weight rather than menopause itself, and, iv) an association between menopause and hypertension, although available data are inconclusive. With regard to the consequences of MetS during menopause, there is no consistent data supporting a causal relationship between menopause and CVD. However, concomitant MetS during menopause appears to increase the risk of CVD. Furthermore, despite the data supporting the association between early menopause and increased risk of T2DM, the association between natural menopause itself and risk of T2DM is not evident. However, the presence and the severity of MetS appears to be associated with an increased risk of T2DM. Although the mechanism is not clear, surgical menopause is strongly linked with a higher incidence of MetS. Interestingly, women with polycystic ovary syndrome (PCOS) have an increased risk of MetS during their reproductive years; however, with menopausal transition, the risk of MetS becomes similar to that of non-PCOS women.

scholarly journals Molecular Mechanisms of Insulin Resistance in Polycystic Ovary Syndrome: Unraveling the Conundrum in Skeletal Muscle?

2019 ◽  
Vol 104 (11) ◽  
pp. 5372-5381 ◽  
Author(s):  
Nigel K Stepto ◽  
Alba Moreno-Asso ◽  
Luke C McIlvenna ◽  
Kirsty A Walters ◽  
Raymond J Rodgers
Keyword(s):  
Insulin Resistance ◽  
Skeletal Muscle ◽  
Polycystic Ovary Syndrome ◽  
Molecular Mechanisms ◽  
Current Knowledge ◽  
Polycystic Ovary ◽  
Evidence Synthesis ◽  
Basic Research ◽  
Future Research ◽  
Ovary Syndrome

Abstract Context Polycystic ovary syndrome (PCOS) is a common endocrine condition affecting 8% to 13% of women across the lifespan. PCOS affects reproductive, metabolic, and mental health, generating a considerable health burden. Advances in treatment of women with PCOS has been hampered by evolving diagnostic criteria and poor recognition by clinicians. This has resulted in limited clinical and basic research. In this study, we provide insights into the current and future research on the metabolic features of PCOS, specifically as they relate to PCOS-specific insulin resistance (IR), that may affect the most metabolically active tissue, skeletal muscle. Current Knowledge PCOS is a highly heritable condition, yet it is phenotypically heterogeneous in both reproductive and metabolic features. Human studies thus far have not identified molecular mechanisms of PCOS-specific IR in skeletal muscle. However, recent research has provided new insights that implicate energy-sensing pathways regulated via epigenomic and resultant transcriptomic changes. Animal models, while in existence, have been underused in exploring molecular mechanisms of IR in PCOS and specifically in skeletal muscle. Future Directions Based on the latest evidence synthesis and technologies, researchers exploring molecular mechanisms of IR in PCOS, specifically in muscle, will likely need to generate new hypothesis to be tested in human and animal studies. Conclusion Investigations to elucidate the molecular mechanisms driving IR in PCOS are in their early stages, yet remarkable advances have been made in skeletal muscle. Overall, investigations have thus far created more questions than answers, which provide new opportunities to study complex endocrine conditions.

Inflammation and impaired adipogenesis in hypertrophic obesity in man

2009 ◽  
Vol 297 (5) ◽  
pp. E999-E1003 ◽  
Author(s):  
Birgit Gustafson ◽  
Silvia Gogg ◽  
Shahram Hedjazifar ◽  
Lachmi Jenndahl ◽  
Ann Hammarstedt ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Adipose Tissue ◽  
Subcutaneous Adipose Tissue ◽  
Molecular Mechanisms ◽  
Whole Body ◽  
Preadipocyte Differentiation ◽  
Metabolic Complications ◽  
Adipose Cell ◽  
Subcutaneous Adipose ◽  
Adipose Cell Size

Obesity is associated mainly with adipose cell enlargement in adult man (hypertrophic obesity), whereas the formation of new fat cells (hyperplastic obesity) predominates in the prepubertal age. Adipose cell size, independent of body mass index, is negatively correlated with whole body insulin sensitivity. Here, we review recent findings linking hypertrophic obesity with inflammation and a dysregulated adipose tissue, including local cellular insulin resistance with reduced IRS-1 and GLUT4 protein content. In addition, the number of preadipocytes in the abdominal subcutaneous adipose tissue capable of undergoing differentiation to adipose cells is reduced in hypertrophic obesity. This is likely to promote ectopic lipid accumulation, a well-known finding in these individuals and one that promotes insulin resistance and cardiometabolic risk. We also review recent results showing that TNFα, but not MCP-1, resistin, or IL-6, completely prevents normal adipogenesis in preadipocytes, activates Wnt signaling, and induces a macrophage-like phenotype in the preadipocytes. In fact, activated preadipocytes, rather than macrophages, may completely account for the increased release of chemokines and cytokines by the adipose tissue in obesity. Understanding the molecular mechanisms for the impaired preadipocyte differentiation in the subcutaneous adipose tissue in hypertrophic obesity is a priority since it may lead to new ways of treating obesity and its associated metabolic complications.

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