Thermogenic profiling using magnetic resonance imaging of dermal and other adipose tissues
Ildiko Kasza, … , Caroline M. Alexander, Scott B. Reeder
Ildiko Kasza, … , Caroline M. Alexander, Scott B. Reeder
Published August 18, 2016
Citation Information: JCI Insight. 2016;1(13):e87146. https://doi.org/10.1172/jci.insight.87146.
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Research Article Metabolism

Thermogenic profiling using magnetic resonance imaging of dermal and other adipose tissues

Abstract

Dermal white adipose tissue (dWAT) was recently recognized for its potential to modify whole body metabolism. Here, we show that dWAT can be quantified using a high-resolution, fat-specific magnetic resonance imaging (MRI) technique. Noninvasive MRI has been used to describe adipocyte depots for many years; the MRI technique we describe uses an advanced fat-specific method to measure the thickness of dWAT, together with the total volume of WAT and the relative activation/fat depletion of brown adipose tissues (BAT). Since skin-embedded adipocytes may provide natural insulation, they provide an important counterpoint to the activation of thermogenic brown and beige adipose tissues, whereby these distinct depots are functionally interrelated and require simultaneous assay. This method was validated using characterized mouse cohorts of a lipodystrophic, dWAT-deficient strain (syndecan-1 KO) and 2 obese models (diet-induced obese mice and genetically obese animals, ob/ob). Using a preliminary cohort of normal human subjects, we found the thickness of skin-associated fat varied 8-fold, from 0.13–1.10 cm; on average, this depot is calculated to weigh 8.8 kg.

Authors

Ildiko Kasza, Diego Hernando, Alejandro Roldán-Alzate, Caroline M. Alexander, Scott B. Reeder

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Figure 1

MRI imaging of the sheath of insulating dWAT in mice.

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MRI imaging of the sheath of insulating dWAT in mice. (A) Female BALB/cJ...
(A) Female BALB/cJ mice were scanned using a standard 8-channel wrist coil array. Serial transverse images, 700-μM thick, were collected for image analysis using clinical OsiriX software. (B) Representative transverse sectional images of mouse bodies; D, dorsal/back; V, ventral/belly; R, right side; L, left side. Depots of interscapular brown adipose tissue (iBAT) were clearly distinguished from proximal white adipose tissue (WAT), including perigonadal WAT (pgWAT) and mammary gland (MG). The skin-associated lipid layer, dermal white adipose tissue (dWAT), was clearly separated from internal adipose depots. The actual size of the transverse sections shown here and in subsequent figures is approximately 3.5 cm. The contrast scale shown at the right was manually set (arbitrary scale 0–3,000). (C) A 3D reconstruction of the body-wide dWAT layer, performed using OsiriX software. (D) Thickness of dWAT varies with various factors; for mice, one of these factors is hair growth. Thus, patches of skin cycle through folliculogenesis (approximately 1 week out of 3; called anagen) (3) and show expanded dWAT (at least 2-fold; see also Figure 2E). Scale bar: 500 μm.