Intramyocellular and Extramyocellular Lipids Are Associated With Arterial Stiffness.
BACKGROUND
Obese and overweight patients are at increased risk of arterial stiffness, and visceral, epicardial and hepatic fat accumulation is associated with cardiovascular disease risk. In general, muscular lipids are stored either in interstitial adipose tissue (extramyocellular lipid (EMCL)) or in lipid droplets within muscle cells (intramyocellular lipid (IMCL)). However, the association between IMCL or EMCL content and arterial stiffness remains unclear. This cross-sectional study aimed to clarify this association.


METHODS
A total of 237 subjects (18-81 years) were enrolled in this study. The IMCL and EMCL contents of the right vastus lateralis muscle were evaluated by proton magnetic resonance spectroscopy. Arterial stiffness was estimated using brachial-ankle pulse wave velocity (baPWV).


RESULTS
There were significant correlations between baPWV and the contents of both IMCL (R = -0.23, P < 0.001) and EMCL (R = 0.53, P < 0.001) in all subjects. The baPWV negatively correlated with IMCL content (R = -0.45, P < 0.001) in females only. In contrast, significant positive correlations were observed between baPWV and EMCL content in both males (R = 0.59, P < 0.001) and females (R = 0.55, P < 0.001). IMCL and EMCL contents contributed independently to baPWV variation after adjustment for age, sex, body mass index, visceral and subcutaneous abdominal fat, upper and lower limb fat, blood pressure, heart rate, and lipid profiles.


CONCLUSIONS
These results suggest that IMCL and EMCL contents may be a risk factor for arterial stiffness, and this association differed with gender and age.
Faculty of Sport and Health Science, Ritsumeikan University, Shiga, Japan.
Natsuki
N
Hasegawa
Faculty of Sport and Health Science, Ritsumeikan University, Shiga, Japan.
Toshiyuki
T
Kurihara
Faculty of Sport and Health Science, Ritsumeikan University, Shiga, Japan.
Koji
K
Sato
Faculty of Sport and Health Science, Ritsumeikan University, Shiga, Japan.
Toshiyuki
T
Homma
Faculty of Sport and Health Science, Ritsumeikan University, Shiga, Japan.
Shumpei
S
Fujie
Faculty of Sport and Health Science, Ritsumeikan University, Shiga, Japan.
Satoshi
S
Fujita
Faculty of Sport and Health Science, Ritsumeikan University, Shiga, Japan.
Kiyoshi
K
Sanada
Faculty of Sport and Health Science, Ritsumeikan University, Shiga, Japan.
Takafumi
T
Hamaoka
Faculty of Sport and Health Science, Ritsumeikan University, Shiga, Japan. iemitsu@fc.ritsumei.ac.jp.
Motoyuki
M
Iemitsu
D050154:Adiposity; D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D050356:Lipid Metabolism; D008297:Male; D008875:Middle Aged; D032342:Muscle Cells / Q000378:metabolism*; D063177:Pulse Wave Analysis; D012737:Sex Factors; D059289:Vascular Stiffness; D055815:Young Adult
adipose tissue; blood pressure; hypertension; magnetic resonance spectroscopy; muscle; pulse wave velocity.