Abstract
We describe a localized proton magnetic resonance spectroscopy ((1)H-MRS) method for in vivo measurement of lipid composition in very small voxels (1.5 mm x 1.5 mm x 1.5 mm) in adipose tissue in mice. The method uses localized point-resolved spectroscopy to collect (1)H spectra from voxels in intra-abdominal white adipose tissue (WAT) and brown adipose tissue (BAT) deposits. Nonlinear least-squares fits of the spectra in the frequency domain allow for accurate calculation of the relative amount of saturated, monounsaturated, and polyunsaturated fatty acids. All spectral data are corrected for spin-spin relaxation. The data show BAT of NMRI mice to be significantly different from BAT of NMRI nu/nu mice in all aspects except for the fraction of monounsaturated fatty acids (FM); for WAT, only the FM is different. BAT and WAT of NMRI mice differ in the amount of saturated and di-unsaturated fatty acids. This method provides a potential tool for studying lipid metabolism in small animal models of disease during the initiation, progression, and manifestation of obesity-related disorders in vivo. Our results clearly demonstrate that localized (1)H-MRS of adipose tissue in vivo is possible at high spatial resolution with voxel sizes down to 3.4 ml.
Highlights
We describe a localized proton magnetic resonance spectroscopy (1H-MRS) method for in vivo measurement of lipid composition in very small voxels (1.5 mm 3 1.5 mm 3 1.5 mm) in adipose tissue in mice
We evaluated an improved 1H-MRS method for in vivo measurements of lipid composition in adipose tissue deposits in mice with a voxel size minimized to 1.5 mm 3 1.5 mm 3 1.5 mm (3.4 ml) by preservation of complete spectral information using a 7 T small animal magnetic resonance tomograph
The measured T2 relaxation times are slightly shorter than the true T2 relaxation times, because the point-resolved spectroscopy (PRESS) sequence does not prevent the effects of diffusion and J-coupling [14, 15]
Summary
We describe a localized proton magnetic resonance spectroscopy (1H-MRS) method for in vivo measurement of lipid composition in very small voxels (1.5 mm 3 1.5 mm 3 1.5 mm) in adipose tissue in mice. Independent of other deposits or their amounts, plays an important role in modulating hepatic insulin action In this line, adipose tissue distribution, lipid composition, levels of specific lipid oxidation products, and Abbreviations: AUC, area under the curve; BAT, brown adipose tissue; FD, fraction of diunsaturated fatty acids; FM, fraction of monounsaturated fatty acids; FOV, field of view; FP, fraction of polyunsaturated fatty acids; FS, fraction of saturated fatty acids; FT, fraction of triunsaturated fatty acids; MCL, mean chain length; MRS, magnetic resonance spectroscopy; NEX, number of repetitions; PRESS, pointresolved spectroscopy; TE, echo time; TR, repetition time; WAT, white adipose tissue; WPF, water proton fraction. Voxel sizes down to 3 mm 3 3 mm 3 3 mm (27 ml) have been realized with localized spectroscopy methods [2], and sizes down to 2.5 mm 3 2.5 mm 3 6 mm (37.5 ml) have been realized using spectroscopic imaging (chemical shift imaging) techniques [3]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
