In vivo magnetic resonance imaging and spectroscopy of various adipose tissue deposits in mice


In vivo magnetic resonance imaging and spectroscopy of various adipose tissue deposits in mice

Strobel, K.; van den Hoff, J.; Pietzsch, J.

An emerging paradigm supports the view that adipose tissue (AT) dysregulation might play a crucial role in the pathogenesis of insulin-resistance, atherosclerosis, and other disease states. In the last years, rodent models have played an important role in the investigation of AT biology and disorder. In this line, non-invasive differentiation and characterization of various AT deposits in the living animal is a current challenge. In the present paper, magnetic resonance imaging (MRI) and spectroscopy (MRS) techniques are applied for quantitative in vivo evaluation of superficial and mediastinal brown adipose tissue (BAT), as well as subcutaneous and intra-abdominal white adipose tissue (WAT) deposits in mice.
All experiments were carried out in NMRI mice and nude mice aging from 8 to 24 weeks. Morphological differentiation between various BAT and WAT deposits was obtained by 1H-MRI at 7 Tesla using a Biospec 70/30 (Bruker, Germany). Images were obtained with high spatial resolution of 156 microns (field of view 4 x 4 cm, matrix size 256 x 256; slice thickness 1.5 to 3 mm). Furthermore, 1H-MRS has been performed to quantify in vivo the different lipid patterns in BAT and WAT deposits using a volume selective PRESS sequence on 3 to 8 mm^3 voxels.
In both nude mice and NMRI mice the various BAT and WAT deposits were clearly distinguished from the non-AT tissue with excellent contrast by T1-weighted MSME MRI sequences. Comparison of MR images with corresponding histological whole-animal sections indicated high specificity and sensitivity of the MRI sequences applied. The high resolution spectra obtained at 7 T allow identification of at least 9 different proton resonances specific for lipids, and thus, for calculation of mono- to polyunsaturated fatty acid ratio in vivo. In this study, nude mice showed a 1.5- to 3-fold higher degree of unsaturation and polyunsaturation of triglyceride fatty acid acyl chains in BAT when compared to NMRI mice. No differences were observed in WAT deposits.
High-resolution MRI and MRS are potentially useful tools for studying the biology of different BAT and WAT deposits non-invasively in small experimental animals in vivo.

  • Poster
    ESMRMB 23. Annual Scientific Meeting, European Society for Magnetic Resonance in Medicine and Biology, 21.-23.09.2006, Warsaw, Poland
  • Abstract in refereed journal
    Magnetic Resonance Materials in Physics, Biology and Medicine 19(2006)Suppl. 1, 236
    ISSN: 0968-5243

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Publ.-Id: 8765