Adipose tissue expandability: the metabolic problems of obesity may arise from the inability to become more obese

2008 ◽  
Vol 36 (5) ◽  
pp. 935-940 ◽  
Author(s):  
Chong Yew Tan ◽  
Antonio Vidal-Puig

The prevalence of obesity is increasing and with it the prevalence of associated metabolic complications. Precisely how obesity results in metabolic disturbances remains unclear. In the face of persistent positive caloric balance, it has been postulated that the capacity of adipose tissue to safely store fat may be vital. This paper explores some of the evidence suggesting that the risk of developing metabolic disturbances is not related to how much fat an individual has, but how well their fat can expand to accommodate the caloric excess. If this is true, the metabolic consequences of obesity may arise from the inability to become more obese.

2021 ◽  
Vol 22 (4) ◽  
pp. 1530
Author(s):  
Katarzyna Maliszewska ◽  
Adam Kretowski

The increased worldwide prevalence of obesity, insulin resistance, and their related metabolic complications have prompted the scientific world to search for new possibilities to combat obesity. Brown adipose tissue (BAT), due to its unique protein uncoupling protein 1 (UPC1) in the inner membrane of the mitochondria, has been acknowledged as a promising approach to increase energy expenditure. Activated brown adipocytes dissipate energy, resulting in heat production. In other words, BAT burns fat and increases the metabolic rate, promoting a negative energy balance. Moreover, BAT alleviates metabolic complications like dyslipidemia, impaired insulin secretion, and insulin resistance in type 2 diabetes. The aim of this review is to explore the role of BAT in total energy expenditure, as well as lipid and glucose homeostasis, and to discuss new possible activators of brown adipose tissue in humans to treat obesity and metabolic disorders.


2022 ◽  
Vol 23 (2) ◽  
pp. 740
Author(s):  
Jocelyne Magré ◽  
Xavier Prieur

Obesity prevalence is increasing worldwide, leading to cardiometabolic morbidities. Adipocyte dysfunction, impairing white adipose tissue (WAT) expandability and metabolic flexibility, is central in the development of obesity-related metabolic complications. Rare syndromes of lipodystrophy characterized by an extreme paucity of functional adipose tissue should be considered as primary adipocyte dysfunction diseases. Berardinelli-Seip congenital lipodystrophy (BSCL) is the most severe form with a near absence of WAT associated with cardiometabolic complications such as insulin resistance, liver steatosis, dyslipidemia, and cardiomyopathy. Twenty years ago, mutations in the BSCL2 gene have been identified as the cause of BSCL in human. BSCL2 encodes seipin, an endoplasmic reticulum (ER) anchored protein whose function was unknown back then. Studies of seipin knockout mice or rats demonstrated how seipin deficiency leads to severe lipodystrophy and to cardiometabolic complications. At the cellular levels, seipin is organized in multimers that are particularly enriched at ER/lipid droplet and ER/mitochondria contact sites. Seipin deficiency impairs both adipocyte differentiation and mature adipocyte maintenance. Experiments using adipose tissue transplantation in seipin knockout mice and tissue-specific deletion of seipin have provided a large body of evidence that liver steatosis, cardiomyopathy, and renal injury, classical diabetic complications, are all consequences of lipodystrophy. Rare adipocyte dysfunctions such as in BSCL are the key paradigm to unravel the pathways that control adipocyte homeostasis. The knowledge gathered through the study of these pathologies may bring new strategies to maintain and improve adipose tissue expandability.


2020 ◽  
Vol 134 (18) ◽  
pp. 2447-2451
Author(s):  
Anissa Viveiros ◽  
Gavin Y. Oudit

Abstract The global prevalence of obesity has been rising at an alarming rate, accompanied by an increase in both childhood and maternal obesity. The concept of metabolic programming is highly topical, and in this context, describes a predisposition of offspring of obese mothers to the development of obesity independent of environmental factors. Research published in this issue of Clinical Science conducted by Litzenburger and colleagues (Clin. Sci. (Lond.) (2020) 134, 921–939) have identified sex-dependent differences in metabolic programming and identify putative signaling pathways involved in the differential phenotype of adipose tissue between males and females. Delineating the distinction between metabolically healthy and unhealthy obesity is a topic of emerging interest, and the precise nature of adipocytes are key to pathogenesis, independent of adipose tissue volume.


Author(s):  
Valerie Larouche ◽  
Caroline Bellavance ◽  
Pauline Tibout ◽  
Sebastien Bergeron ◽  
David Simonyan ◽  
...  

Abstract Objectives Chronic metabolic disturbances related to cancer treatment are well reported among survivors of pediatric acute lymphoblastic leukemia (ALL). However, few studies have investigated the incidence of these complications during the phase of chemotherapy. We evaluated the incidence of acute metabolic complications occurring during therapy in our cohort of patients diagnosed with ALL. Methods A prospective study involving 50 ALL pediatric patients diagnosed and treated between 2012 and 2016 in our oncology unit. We collected weight, blood pressure, fasting plasma glucose and hemoglobin A1C (HBA1c) levels during the two years of therapy. Results Obesity and overweight occurred in 43 and 25%, respectively among patients and have been reached at 12 months of chemotherapy. About 26% of the patients developed high blood pressure and 14% experienced hyperglycemias without meeting diabetes criteria. There was a significant decrease of HBA1c levels between the beginning and the end of therapy (p<0.0001). Conclusions Increase of body mass index in our ALL pediatric patients occurred during the first months of therapy and plateaued after a year of treatment. We should target this population for early obesity prevention. HbA1c levels measured during therapy did not reveal diabetes criteria. Hence, fasting blood glucose levels are sufficient to monitor ALL pediatric patients’ glycemia.


2017 ◽  
Vol 40 (12) ◽  
pp. 676-682 ◽  
Author(s):  
Maria Huguet ◽  
Lida Rodas ◽  
Miquel Blasco ◽  
Luis F. Quintana ◽  
Jordi Mercadal ◽  
...  

Background Regional citrate anticoagulation (RCA) is being used increasingly in continuous renal replacement therapy (CRRT) as a safer alternative to heparin. However, complex metabolic control to avoid side effects have generated discrepancies about its introduction into everyday practice. We aimed to compare both anticoagulation techniques in terms of efficacy, safety and feasibility. Methods Observational retrospective study performed in 3 specialized ICUs in patients receiving CVVHDF with RCA between January 2013 and May 2016. Heparin-treated patients matched by age, sex and disease severity treated in the preceding year were selected as historic controls. Filter lifetime, number of filters used, haemorrhagic complications and metabolic complications were recorded. Results 54 patients (27 treated with RCA and 27 with heparin) were included in the study. Filter lifetimes in the first 72 hours were 55.1 ± 21.8 hours in the RCA group compared to 38.8 ± 24.8 hours in the heparin group, (p = 0.004). In addition, the number of filters used in the first 72 hours was significantly higher in the heparin group (2.4 ± 1.3 vs. 1.5 ± 0.7; p = 0.004). There was a trend toward a lower incidence of bleeding in the RCA group, with a significantly lower red blood cell transfusion rate (p = 0.027) in the citrate group. No clinically significant metabolic disturbances were observed in the RCA group. Regarding outcomes, there were no significant differences between groups. Conclusions These results suggest that the implementation of CVVHDF with RCA using concentrated citrate solutions prolongs filter lifetime, achieves a longer effective hemodiafiltration time and is a safe and feasible method.


2017 ◽  
Vol 127 (2) ◽  
pp. 92-95
Author(s):  
Karolina Goral ◽  
Justyna Siwiela-Tomaszczyk ◽  
Renata Krzyszycha ◽  
Michał Skrzypek

Abstract The objective of the study is a critical analysis of the selected alternative diets used in the treatment of obesity inconsistent with the recommended standards, from the perspective of clinical dieticians, based on up-to-date guidelines for dietary management of obesity. Attention was paid to the assumptions of the selected alternative diets, some physiological mechanisms related with their use, as well as the deficit of data pertaining their distant effectiveness and safety. In the context of the current epidemiological situation concerning the prevalence of obesity, it is justifiable to undertake actions aimed at the professionalization of dietary management in obesity, consisting in the application of the treatment methods based on data generated in the EBM paradigm, with a simultaneous indication and criticism of dietary pseudo-therapies with unconfirmed curative value which, in addition, do not guarantee the reduction of the risk of metabolic complications of obesity.


2012 ◽  
Vol 108 (11) ◽  
pp. 1915-1923 ◽  
Author(s):  
Cherlyn Ding ◽  
Dan Gao ◽  
John Wilding ◽  
Paul Trayhurn ◽  
Chen Bing

Vitamin D deficiency and the rapid increase in the prevalence of obesity are both considered important public health issues. The classical role of vitamin D is in Ca homoeostasis and bone metabolism. Growing evidence suggests that the vitamin D system has a range of physiological functions, with vitamin D deficiency contributing to the pathogenesis of several major diseases, including obesity and the metabolic syndrome. Clinical studies have shown that obese individuals tend to have a low vitamin D status, which may link to the dysregulation of white adipose tissue. Recent studies suggest that adipose tissue may be a direct target of vitamin D. The expression of both the vitamin D receptor and 25-hydroxyvitamin D 1α-hydroxylase (CYP27B1) genes has been shown in murine and human adipocytes. There is evidence that vitamin D affects body fat mass by inhibiting adipogenic transcription factors and lipid accumulation during adipocyte differentiation. Some recent studies demonstrate that vitamin D metabolites also influence adipokine production and the inflammatory response in adipose tissue. Therefore, vitamin D deficiency may compromise the normal metabolic functioning of adipose tissue. Given the importance of the tissue in energy balance, lipid metabolism and inflammation in obesity, understanding the mechanisms of vitamin D action in adipocytes may have a significant impact on the maintenance of metabolic health. In the present review, we focus on the signalling role of vitamin D in adipocytes, particularly the potential mechanisms through which vitamin D may influence adipose tissue development and function.


2021 ◽  
Vol 41 (Supplement_1) ◽  
pp. S69-S74
Author(s):  
Summer E Hanson

Abstract One of the earliest reported cases of autologous fat grafting (AFG) was by Neuber in 1893 and consisted of the transfer of small lobules of fat from the upper arm for cicatrical depression of the face. He advocated the use of smaller grafts, noting that pieces larger than the size of a bean would form cysts. In 1895, Czerny excised a lumbar lipoma and transplanted it to the chest for breast reconstruction. Since these early reports, the knowledge base around AFG has expanded exponentially, as illustrated by the other papers within this special topic. As we embark on the next phase of AFG in the clinical setting, there are several directions which are near-clinical translation. This paper discusses future directions in fat grafting that build on optimization of our current techniques as clinical indications expand, such as supplementing purified lipoaspirate and the associated regulatory burden, or deconstructing adipose tissue to selectively use adipose graft components for a variety of regenerative indications.


2021 ◽  
Vol 37 (1) ◽  
pp. 549-573
Author(s):  
Conan J.O. O'Brien ◽  
Emma R. Haberman ◽  
Ana I. Domingos

The prevalence of obesity is on the rise. What was once considered a simple disease of energy imbalance is now recognized as a complex condition perpetuated by neuro- and immunopathologies. In this review, we summarize the current knowledge of the neuroimmunoendocrine mechanisms underlying obesity. We examine the pleiotropic effects of leptin action in addition to its established role in the modulation of appetite, and we discuss the neural circuitry mediating leptin action and how this is altered with obesity, both centrally (leptin resistance) and in adipose tissues (sympathetic neuropathy). Finally, we dissect the numerous causal and consequential roles of adipose tissue macrophages in obesity and highlight recent key studies demonstrating their direct role in organismal energy homeostasis.


2009 ◽  
Vol 297 (5) ◽  
pp. E999-E1003 ◽  
Author(s):  
Birgit Gustafson ◽  
Silvia Gogg ◽  
Shahram Hedjazifar ◽  
Lachmi Jenndahl ◽  
Ann Hammarstedt ◽  
...  

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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