The “adipose tissue expandability” hypothesis: a potential mechanism for insulin resistance in obese youth

Author(s):  
Sonia Caprio ◽  
Bridget Pierpont ◽  
Romy Kursawe

AbstractObesity has become a major global health challenge of the 21st century, as it is associated with the onset of type 2 diabetes (T2D) and cardiovascular complications, even at a very early age in life. The root causes of pediatric obesity remain incompletely understood. The obesity epidemic together with the relationship of obesity to the growing population burden of chronic disease presents unprecedented research opportunities and challenges. Decades of obesity-related research funded by governments around the world have yielded many important discoveries about both etiological pathways and preventive or therapeutic interventions. Yet, there is a sense that the problem is outpacing these research efforts. Obesity poses a significant risk for the development of cardiovascular disease (CVD) , diabetes and certain cancers thereby shortening life expectancy. Nevertheless, many obese individuals do not develop any of these comorbidities. One hypothesis explaining this dilemma is that total body fat is not the culprit of adverse health in obesity rather the relative proportion of lipids in various fat depots is what determines the metabolic risk. In this review, we describe the role of altered fat partitioning in youth onset obesity and its relation to fatty liver and T2D during adolescence.

1990 ◽  
Vol 259 (6) ◽  
pp. R1117-R1125 ◽  
Author(s):  
F. D. Newby ◽  
M. DiGirolamo ◽  
G. A. Cotsonis ◽  
M. H. Kutner

We analyzed retrospectively data from 148 chow-fed male Wistar rats killed between the age of 6 wk and 2 yr while varying in body weight from 136 to 917 g. The purpose of this study was to clarify the relationship of body weight and body lipid content with the composition and cellularity of the epididymal and retroperitoneal fat depots. A positive linear association was found between body weight and body water or fat-free dry residue, whereas total body lipid exhibited a curvilinear relationship with body weight. The weight of the epididymal pads was linearly related to body weight but not to body lipid. In contrast, retroperitoneal pad weight was exponentially related to body weight and paralleled total body lipid. A strong linear correlation was found between total body lipid and weight (r = 0.959) or depot lipid content (r = 0.967) of the retroperitoneal fat pads. In this rat model of aging and spontaneous obesity, significant regional differences exist in adipose depot composition and cellularity. A practical outcome of this study is a simple and accurate prediction of body lipid content from the gravimetric determination of the retroperitoneal fat depots.


2016 ◽  
Vol 57 (1) ◽  
pp. F7-F21 ◽  
Author(s):  
Aurelie Nguyen Dinh Cat ◽  
Malou Friederich-Persson ◽  
Anna White ◽  
Rhian M Touyz

Understanding the mechanisms linking obesity with hypertension is important in the current obesity epidemic as it may improve therapeutic interventions. Plasma aldosterone levels are positively correlated with body mass index and weight loss in obese patients is reported to be accompanied by decreased aldosterone levels. This suggests a relationship between adipose tissue and the production/secretion of aldosterone. Aldosterone is synthesized principally by the adrenal glands, but its production may be regulated by many factors, including factors secreted by adipocytes. In addition, studies have reported local synthesis of aldosterone in extra-adrenal tissues, including adipose tissue. Experimental studies have highlighted a role for adipocyte-secreted aldosterone in the pathogenesis of obesity-related cardiovascular complications via the mineralocorticoid receptor. This review focuses on how aldosterone secretion may be influenced by adipose tissue and the importance of these mechanisms in the context of obesity-related hypertension.


Author(s):  
Engy A. Ali ◽  
Mariam Raafat

Abstract Background Our goal was to find out the relation between mammographic densities and cancer of the breast according to the recent ACR classification. From the medical records of Kasereliny Hospital, 49,409 women were subjected to digital mammography for screening, of which 1500 breast cancer cases were collected. The mammographic categories of breast density were ACR-A, B, C, and D, which were detected by two senior radiologists. All radiological classifications were made using both standard mammographic views bilaterally. Two-sided tests of statistical significance were represented by all the P values. Results From 2014 to 2019, 49,409 women came for digital mammographic screening, their age ranges between 40 and 65, and all of them are included in the study. One thousand cases of breast cancer cases were radiologically and pathologically diagnosed. Different densities were arranged in descending pattern depending on the frequency of positive cases: D (13.7%), C (3.3%), B (2.7%), A (2.2%). There is positive significant risk ratio among every higher mammographic density in comparison to the lower density. Conclusion Our study results show that the risk of breast cancer is in close relation to the mammographic breast density.


2019 ◽  
Vol 116 (22) ◽  
pp. 10952-10961 ◽  
Author(s):  
Joseph Ochaba ◽  
Gianna Fote ◽  
Marketta Kachemov ◽  
Soe Thein ◽  
Sylvia Y. Yeung ◽  
...  

Neuroinflammation is an important contributor to neuronal pathology and death in neurodegenerative diseases and neuronal injury. Therapeutic interventions blocking the activity of the inflammatory kinase IKKβ, a key regulator of neuroinflammatory pathways, is protective in several animal models of neurodegenerative disease and neuronal injury. In Huntington’s disease (HD), however, significant questions exist as to the impact of blocking or diminishing the activity of IKKβ on HD pathology given its potential role in Huntingtin (HTT) degradation. In cell culture, IKKβ phosphorylates HTT serine (S) 13 and activates HTT degradation, a process that becomes impaired with polyQ expansion. To investigate the in vivo relationship of IKKβ to HTT S13 phosphorylation and HD progression, we crossed conditional tamoxifen-inducible IKKβ knockout mice with R6/1 HD mice. Behavioral assays in these mice showed a significant worsening of HD pathological phenotypes. The increased behavioral pathology correlated with reduced levels of endogenous mouse full-length phospho-S13 HTT, supporting the importance of IKKβ in the phosphorylation of HTT S13 in vivo. Notably, many striatal autophagy genes were up-regulated in HD vs. control mice; however, IKKβ knockout partially reduced this up-regulation in HD, increased striatal neurodegeneration, and enhanced an activated microglial response. We propose that IKKβ is protective in striatal neurons early in HD progression via phosphorylation of HTT S13. As IKKβ is also required for up-regulation of some autophagy genes and HTT is a scaffold for selective autophagy, IKKβ may influence autophagy through multiple mechanisms to maintain healthy striatal function, thereby reducing neuronal degeneration to slow HD onset.


1999 ◽  
Vol 31 (Supplement) ◽  
pp. S318
Author(s):  
T. Okuyama ◽  
S. Owens ◽  
P. Barbeau ◽  
S. Riggs ◽  
M. Bauman ◽  
...  

1982 ◽  
Vol 98 (3) ◽  
pp. 571-578 ◽  
Author(s):  
O. Y. Abdallah ◽  
Karima A. Shahin ◽  
M. G. A. Latif

SUMMARYDissection data from an experiment involving 12 buffalo, nine ♂Friesian × ♀Egyptian native Baladi (½ Friesian) and nine ♂ Friesian × ♀ ½ Friesian (¾ Friesian) bulls were used to examine the growth and partition of fat between depots and its distribution in different regions of the carcass.Growth of total dissectible carcass fat (TCF) and its component depots (subcutaneous (SCF); intermuscular (IMF); kidney knob and channel (KKCF)) and total offal fat (TOF) and its component depots (caul (CF); mesenteric (MF); heart (HF)) relative to total body fat (TBF = TCF + TOF) was examined.Relative to TBF, no significant differences in growth coefficients or adjusted means of TCF, TOF, carcass SCF and carcass KKCF were found between genotypes. Compared with ¾ Friesians, buffaloes had lower rates of deposition of CF and IMF, lower proportion of TBF deposited as MF and a greater proportion of HF.As dissected side fat (DSF) increased, the proportion of fat decreased in the distal hind limb and neck, increased in the abdominal wall and adjacent ventral part of the thoracic cavity and remained unchanged in the other carcass regions. Fat growth coefficients differed between genotype groups in all carcass regions except the distal hind limb, fore limb and thorax. A posterior-anterior decrease in growth impetus of fat from the loin (b < 1) towards the neck (b > 1) was traced in buffaloes while the growth coefficients within all dorsal cuts in cattle did not differ significantly from 1. Compared with cattle, buffaloes had more of the DSF occurring in the combined expensive cuts with higher SCF: IMF ratio only at the upper limits of fatness considered in the present work.It is argued that buffaloes relative to Friesian cross-breds have a beef-type fat partition and that characteristic changes in rates of increase in fat depots relative to empty-body weight and in fat in various regions relative to total fat could be related to the increase in Friesian blood.


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