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This Article Full Text Full Text (PDF) All Versions of this Article: 295/4/R1060    most recent 90367.2008v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Web of Science (2) Citing Articles via Google Scholar Google Scholar Articles by Velan, S. S. Articles by Alway, S. E. Search for Related Content PubMed PubMed Citation Articles by Velan, S. S. Articles by Alway, S. E.

APPETITE, OBESITY, AND DIGESTION

Distinct patterns of fat metabolism in skeletal muscle of normal-weight, overweight, and obese humans

¹Center for Advanced Imaging and Department of Radiology, ²Center for Interdisciplinary Research in Cardiovascular Sciences, ³Department of Community Medicine, ⁴Department of Physiology and Pharmacology, ⁶Departments of Biochemistry, Microbiology, and Immunology, and ⁸Department of Exercise Physiology, West Virginia University, Morgantown, West Virginia; ⁵Department of Radiology, University of California, Los Angeles, California; and ⁷Magnetic Resonance Imaging and Spectroscopy Section, National Institute on Aging, National Institutes of Health, Baltimore, Maryland

Submitted 17 April 2008 ; accepted in final form 28 July 2008

The link between body weight, lipid metabolism, and health risks is poorly understood and difficult to study. Magnetic resonance spectroscopy (MRS) permits noninvasive investigation of lipid metabolism. We extended existing two-dimensional MRS techniques to permit quantification of intra- and extramyocellular lipid (IMCL and EMCL, respectively) compartments and their degree of unsaturation in human subjects and correlated these results with body mass index (BMI). Using muscle creatine for normalization, we observed a statistically significant (P < 0.01) increase in the IMCL-to-creatine ratio with BMI (n = 8 subjects per group): 5.9 ± 1.7 at BMI < 25, 10.9 ± 1.82 at 25 < BMI < 30, and 13.1 ± 0.87 at BMI > 30. Similarly, the degree of IMCL unsaturation decreased significantly (P < 0.01) with BMI: 1.51 ± 0.08 at BMI < 25, 1.30 ± 0.11 at 25 < BMI < 30, and 0.90 ± 0.14 at BMI > 30. We conclude that important aspects of lipid metabolism can be evaluated by two-dimensional MRS and propose that degree of unsaturation measured noninvasively may serve as a biomarker for lipid metabolic defects associated with obesity.

magnetic resonance spectroscopy; lipid unsaturation; intramyocellular lipid; extramyocellular lipid