Long‐TE 1H MRS suggests that liver fat is more saturated than subcutaneous and visceral fat |
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Authors: | Jesper Lundbom Antti Hakkarainen Sanni Söderlund Jukka Westerbacka Nina Lundbom Marja‐Riitta Taskinen |
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Institution: | 1. Email:jesse lundbom@gmail.com;4. Department of Medicine, Division of Cardiology, University of Helsinki, Helsinki, Finland;5. Helsinki Medical Imaging Centre, University of Helsinki, Helsinki, Finland |
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Abstract: | Cross‐talk between adipose tissue and liver is disturbed in the metabolic syndrome. Moreover, the relative fatty acid composition of adipose and liver fat is poorly characterized. Long‐TE 1H MRS can determine the unsaturation and polyunsaturation of adipose tissue. The aim of this study was to use long‐TE 1H MRS to determine the composition of liver fat and its relation to adipose tissue composition. Sixteen subjects with increased liver fat (>5%) were recruited for the study. Using TE = 200 ms, we were able to resolve the olefinic (?CH, 5.3 ppm) and water (H2O, 4.7 ppm) resonances in liver spectra and to obtain a repeatable estimate of liver fat unsaturation (coefficient of variation, 2.3%). With TE = 135 ms, the diallylic (?C? CH2? C?, 2.8 ppm) resonance was detectable in subjects with a liver fat content above 15%. Long‐TE 1H MRS was also used to determine the unsaturation in subcutaneous (n = 16) and visceral (n = 11) adipose tissue in the same subjects. Liver fat was more saturated (double bonds per fatty acid chain, 0.812 ± 0.022) than subcutaneous (double bonds per fatty acid chain, 0.862 ± 0.022, p < 0.0004) or visceral (double bonds per fatty acid chain, 0.865 ± 0.033, p < 0.0004) fat. Liver fat unsaturation correlated with subcutaneous unsaturation (R = 0.837, p < 0.0001) and visceral unsaturation (R = 0.879, p < 0.0004). The present study introduces a new noninvasive method for the assessment of the composition of liver fat. The results suggest that liver fat is more saturated than subcutaneous or visceral adipose tissue, which may be attributed to differences in de novo lipogenesis. Copyright © 2010 John Wiley & Sons, Ltd. |
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Keywords: | 1H MRS liver fat adipose tissue fatty acid unsaturation |
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