PIXImus DXA with Different Software Needs Individual Calibration to Accurately Predict Fat Mass

Johnston, Sarah; Peacock, W L; Bell, Lynn; Lonchampt, Michel; Speakman, John R.

doi:10.1038/oby.2005.191

Cited by 36 publications

(36 citation statements)

References 14 publications

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“…Animals receiving the restricted diet lost on an average 1.3G0.32 g (K5.5%) of BM, which was attributed to a decrease in LM while FM increased (figure 2). Large errors in small animal DXA estimates of FM have been shown for animals with less than 5 g of fat ( Johnston et al 2005) and since LM is calculated by subtraction of FM from total tissue mass, both LM and FM for restricted animals may be incorrect. This may also explain why FM of restricted animals was not different from controls post-treatment.…”

Section: Resultsmentioning

confidence: 99%

Having it all: historical energy intakes do not generate the anticipated trade-offs in fecundity

Johnston

Grune

Bell³

et al. 2006

Proc. R. Soc. B.

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An axiom of life-history theory, and fundamental to our understanding of ageing, is that animals must trade-off their allocation of resources since energy and nutrients are limited. Therefore, animals cannot 'have it all'-combine high rates of fecundity with extended lifespans. The idea of life-history trade-offs was recently challenged by the discovery that ageing may be governed by a small subset of molecular processes independent of fitness. We tested the 'trade-off' and 'having it all' theories by examining the fecundities of C57BL/6J mice placed onto four different dietary treatments that generated caloric intakes from K21 to C8.6% of controls. We predicted body fat would be deposited in relation to caloric intake. Excessive body fat is known to cause co-morbidities that shorten lifespan, while caloric restriction enhances somatic protection and increases longevity. The trade-off model predicts that increased fat would be tolerated because reproductive gain offsets shortened longevity, while animals on a restricted intake would sacrifice reproduction for lifespan extension. The responses of body fat to treatments followed our expectations, however, there was a negative relationship between reproductive performance (fecundity, litter mass) and historical intake/body fat. Our dietary restricted animals had lower protein oxidative damage and appeared able to combine life-history traits in a manner contrary to traditional expectations by having increased fecundity with the potential to have extended lifespans.

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Section: Resultsmentioning

confidence: 99%

Having it all: historical energy intakes do not generate the anticipated trade-offs in fecundity

Johnston

Grune

Bell³

et al. 2006

Proc. R. Soc. B.

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“…There are some controversies regarding the accuracy of measuring fat mass between DEXA scan and chemical extraction (carcass analysis). Johnston et al (17) found that DEXA scan underestimated fatty mass for obese animals and overestimated fatty mass for lean animals. However, other authors found that DEXA scan overestimated fat mass content in lean and obese mice (3,26).…”

Section: Discussionmentioning

confidence: 99%

Abdominal fat analyzed by DEXA scan reflects visceral body fat and improves the phenotype description and the assessment of metabolic risk in mice

Chen

Wilson

Khaksari

et al. 2012

American Journal of Physiology-Endocrinology and Metabolism

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Abdominal fat analyzed by DEXA scan reflects visceral body fat and improves the phenotype description and the assessment of metabolic risk in mice. Am J Physiol Endocrinol Metab 303: E635-E643, 2012. First published July 3, 2012 doi:10.1152/ajpendo.00078.2012Clinical studies have demonstrated a strong relationship between visceral fat content and metabolic diseases, such as type 2 diabetes and liver steatosis. Obese mouse models are an excellent tool to study metabolic diseases; however, there are limited methods for the noninvasive measurement of fat distribution in mice. Although micromagnetic resonance imaging and microcomputed tomography are the "gold standards" in the measurement of fat distribution, more economical and accessible methods are required. Dual energy X-ray absorptiometry (DEXA) is an effective method in characterizing fat content; however, it cannot discriminate between visceral and subcutaneous fat depots. We demonstrate that an evaluation of abdominal fat content measured by DEXA through the selection of one localized abdominal area strongly correlates with visceral fat content in C57BL/6J mice. We found that DEXA is able to measure fat pad volume ex vivo with high accuracy; however, the measurement of visceral fat in vivo shows an overestimation caused by subcutaneous tissue interference. The overestimation is almost constant for a wide range of values, and thus it is possible to correct the data for a more accurate estimation of visceral fat content. We demonstrate the utility of this technique in characterizing phenotypes of several obese mouse models (ob/ob, db/db, MC4R-KO, and DIO) and evaluating the effect of treatments on visceral fat content in longitudinal studies. Additionally, we also establish abdominal obesity as a potential biomarker for metabolic abnormalities (liver fat accumulation, insulin resistance/ diabetes) in mice, similar to that described in humans. dual-energy X-ray absorptiometry scan; metabolic diseases; glucose tolerance test; fat distribution ADIPOSE TISSUE IS NOT DISTRIBUTED UNIFORMLY in the body; instead, it accumulates in specific compartments as either visceral adipose tissue (VAT) or subcutaneous adipose tissue (SAT). Anatomically distinct body fat depots have unique metabolic properties (30). VAT has proatherogenic and prothrombic characteristics (35). VAT also has relatively more capillaries and efferent sympathetic axons per unit of volume than SAT (39). Visceral adipocytes exhibit increased production of inflammatory mediators such as tumor necrosis factor-␣, interleukins, and other cytokines but secrete less leptin and adiponectin than SAT (36). It has also been shown that insulin effect (antilipolytic) is lower and catecholamine effect (lipolytic) higher in VAT, enabling visceral fat to release free fatty acids more extensively. More importantly, due to its anatomic position, secretions from visceral adipocytes have easy access to the liver through the portal system (2).Body composition measurement and fat distribution are important to study and unde...

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“…The software enabled a region of interest to be created to exclude the head with the mask from analysis [15]. Data were corrected with a calibration formula specific to our machine that has been generated by the linear regression of fat content determined by DXA analysis, with the fat content as determined by soxhlet chemical extraction (see [25] for detailed description of the procedure).…”

Section: Body Compositionmentioning

confidence: 99%

Factors influencing individual variability in high fat diet-induced weight gain in out-bred MF1 mice

Vaanholt¹,

Sinclair²,

Mitchell³

et al. 2015

Physiology & Behavior

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PIXImus DXA with Different Software Needs Individual Calibration to Accurately Predict Fat Mass

Cited by 36 publications

References 14 publications

Having it all: historical energy intakes do not generate the anticipated trade-offs in fecundity

Having it all: historical energy intakes do not generate the anticipated trade-offs in fecundity

Abdominal fat analyzed by DEXA scan reflects visceral body fat and improves the phenotype description and the assessment of metabolic risk in mice

Factors influencing individual variability in high fat diet-induced weight gain in out-bred MF1 mice

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