Diet, obesity and diabetes: a current update

2006 ◽  
Vol 112 (2) ◽  
pp. 93-111 ◽  
Author(s):  
Celia G. Walker ◽  
M. Gulrez Zariwala ◽  
Mark J. Holness ◽  
Mary C. SUGDEN

The prevalence of obesity has been increasing at a rapid rate over the last few decades. Although the primary defect can be attributed to an imbalance of energy intake over energy expenditure, the regulation of energy balance is now recognized to be complex. Adipose-tissue factors play a central role in the control of energy balance and whole-body fuel homoeostasis. The regulation of adipose-tissue function, in particular its secretion of adipokines, is impaired by increases in adipose mass associated with obesity, and with the development of insulin resistance and Type 2 diabetes. This review analyses adipose-regulated energy input and expenditure, together with the impact of dietary macronutrient composition on energy balance in relation to susceptibility to the development of obesity and Type 2 diabetes, and how these metabolic conditions may be exacerbated by the consequences of abnormal adipose function. By gaining a greater understanding of how energy balance is controlled in normal, and in obese and diabetic states, a more practical approach can be employed to prevent and better treat obesity and metabolic disorders.

2014 ◽  
Vol 10 (01) ◽  
pp. 64 ◽  
Author(s):  
Tina Rönn ◽  
Charlotte Ling ◽  
◽  

It is well established that exercise promotes health, and reduces people’s risks for developing type 2 diabetes and becoming obese. But just how exercise performs this, at a cellular level, and what molecular and physiologic steps are involved and in what order, are still not fully understood. Metabolic disorders are often influenced by interactions between genetic and environmental factors. One possible explanation for how the environment may influence the genome is through epigenetic mechanisms–that is–chemical modifications to the DNA itself. Epigenetic factors include, for example, DNA methylation, histone modifications, and different RNA-mediated processes, which all have the ability to bind to DNA or affect the chromatin structure and thereby change how specific genes are interpreted and expressed. In this short review, we focus on describing how exercise influences the genome-wide DNA methylation pattern, including candidate genes for obesity and type 2 diabetes, in human adipose tissue.


Endocrinology ◽  
2010 ◽  
Vol 151 (5) ◽  
pp. 1998-2007 ◽  
Author(s):  
Matthew C. Ernst ◽  
Mark Issa ◽  
Kerry B. Goralski ◽  
Christopher J. Sinal

Obesity, characterized by an excess of adipose tissue, is an established risk factor for cardiovascular disease and type 2 diabetes. Different mechanisms linking obesity with these comorbidities have been postulated but remain poorly understood. Adipose tissue secretes a number of hormone-like compounds, termed adipokines, that are important for the maintenance of normal glucose metabolism. Alterations in the secretion of adipokines with obesity are believed to contribute to the undesirable changes in glucose metabolism that ultimately result in the development of type 2 diabetes. In the present study, we have shown that serum levels of the novel adipokine chemerin are significantly elevated in mouse models of obesity/diabetes. The expression of chemerin and its receptors, chemokine-like receptor 1, chemokine (C-C motif) receptor-like 2, and G protein-coupled receptor 1 are altered in white adipose, skeletal muscle, and liver tissue of obese/diabetic mice. Administration of exogenous chemerin exacerbates glucose intolerance, lowers serum insulin levels, and decreases tissue glucose uptake in obese/diabetic but not normoglycemic mice. Collectively, these data indicate that chemerin influences glucose homeostasis and may contribute to the metabolic derangements characteristic of obesity and type 2 diabetes.


Author(s):  
Peng Tang ◽  
Sam Virtue ◽  
Jian Yi Gerald Goie ◽  
Chin Wen Png ◽  
Jing Guo ◽  
...  

AbstractDysfunction of adipocytes and adipose tissue is a primary defect in obesity and obesity-associated metabolic diseases. Interferon regulatory factor 3 (IRF3) has been implicated in adipogenesis. However, the role of IRF3 in obesity and obesity-associated disorders remains unclear. Here, we show that IRF3 expression in human adipose tissues is positively associated with insulin sensitivity and negatively associated with type 2 diabetes. In mouse pre-adipocytes, deficiency of IRF3 results in increased expression of PPARγ and PPARγ-mediated adipogenic genes, leading to increased adipogenesis and altered adipocyte functionality. The IRF3 knockout (KO) mice develop obesity, insulin resistance, glucose intolerance, and eventually type 2 diabetes with aging, which is associated with the development of white adipose tissue (WAT) inflammation. Increased macrophage accumulation with M1 phenotype which is due to the loss of IFNβ-mediated IL-10 expression is observed in WAT of the KO mice compared to that in wild-type mice. Bone-marrow reconstitution experiments demonstrate that the nonhematopoietic cells are the primary contributors to the development of obesity and both hematopoietic and nonhematopoietic cells contribute to the development of obesity-related complications in IRF3 KO mice. This study demonstrates that IRF3 regulates the biology of multiple cell types including adipocytes and macrophages to prevent the development of obesity and obesity-related complications and hence, could be a potential target for therapeutic interventions for the prevention and treatment of obesity-associated metabolic disorders.


Author(s):  
Daniel Cuevas-Ramos ◽  
Carlos A. Aguilar-Salinas

AbstractFibroblast growth factors (FGFs) are a superfamily of 22 proteins related to cell proliferation and tissue repair after injury. A subgroup of three proteins, FGF19, FGF21, and FGF23, are major endocrine mediators. These three FGFs have low affinity to heparin sulfate during receptor binding; in contrast they have a strong interaction with the cofactor Klotho/β-Klotho. FGF21 has received particular attention because of its key role in carbohydrate, lipids, and energy balance regulation. FGF21 improves glucose and lipids metabolism as well as increasing energy expenditure in animal models and humans. Conditions that induce human physical stress such as exercise, lactation, obesity, insulin resistance, and type 2 diabetes influence FGF21 circulating levels. FGF21 also has an anti-oxidant function in human metabolic diseases which contribute to understanding the FGF21 compensatory increment in obesity, the metabolic syndrome, and type 2 diabetes. Interestingly, energy expenditure and weight loss is induced by FGF21. The mechanism involved is through “browning” of white adipose tissue, increasing brown adipose tissue activity and heat production. Therefore, clinical evaluation of therapeutic action of exogenous FGF21 administration is warranted, particularly to treat diabetes and obesity.


2020 ◽  
Vol 21 (13) ◽  
pp. 4773
Author(s):  
Alana Deutsch ◽  
Daorong Feng ◽  
Jeffrey E. Pessin ◽  
Kosaku Shinoda

Adipose tissue is an important regulator of whole-body metabolism and energy homeostasis. The unprecedented growth of obesity and metabolic disease worldwide has required paralleled advancements in research on this dynamic endocrine organ system. Single-cell RNA sequencing (scRNA-seq), a highly meticulous methodology used to dissect tissue heterogeneity through the transcriptional characterization of individual cells, is responsible for facilitating critical advancements in this area. The unique investigative capabilities achieved by the combination of nanotechnology, molecular biology, and informatics are expanding our understanding of adipose tissue’s composition and compartmentalized functional specialization, which underlie physiologic and pathogenic states, including adaptive thermogenesis, adipose tissue aging, and obesity. In this review, we will summarize the use of scRNA-seq and single-nuclei RNA-seq (snRNA-seq) in adipocyte biology and their applications to obesity and diabetes research in the hopes of increasing awareness of the capabilities of this technology and acting as a catalyst for its expanded use in further investigation.


2013 ◽  
Vol 304 (5) ◽  
pp. E466-E477 ◽  
Author(s):  
Jianping Ye ◽  
Owen P. McGuinness

Chronic inflammation is a characteristic of obesity and is associated with accompanying insulin resistance, a hallmark of type 2 diabetes mellitus (T2DM). Although proinflammatory cytokines are known for their detrimental effects on adipose tissue function and insulin sensitivity, their beneficial effects in the regulation of metabolism have not drawn sufficient attention. In obesity, inflammation is initiated by a local hypoxia to augment angiogenesis and improve adipose tissue blood supply. A growing body of evidence suggests that macrophages and proinflammatory cytokines are essential for adipose remodeling and adipocyte differentiation. Phenotypes of multiple lines of transgenic mice consistently suggest that proinflammatory cytokines increase energy expenditure and act to prevent obesity. Removal of proinflammatory cytokines by gene knockout decreases energy expenditure and induces adult-onset obesity. In contrast, elevation of proinflammatory cytokines augments energy expenditure and decreases the risk for obesity. Anti-inflammatory therapies have been tested in more than a dozen clinical trials to improve insulin sensitivity and glucose homeostasis in patients with T2DM, and the results are not encouraging. One possible explanation is that anti-inflammatory therapies also attenuate the beneficial effects of inflammation in stimulating energy expenditure, which may have limited the efficacy of the treatment by promoting energy accumulation. Thus, the positive effects of proinflammatory events should be considered in evaluating the impact of inflammation in obesity and type 2 diabetes.


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