Compositional marker in vivo reveals intramyocellular lipid turnover during fasting-induced lipolysis.
Sci Rep
; 8(1): 2750, 2018 02 09.
Article
em En
| MEDLINE
| ID: mdl-29426847
ABSTRACT
Intramyocellular lipid (IMCL) is of particular metabolic interest, but despite many proton magnetic resonance spectroscopy (1H MRS) studies reporting IMCL content measured by the methylene (CH2) resonance signal, little is known about its composition. Here we validated IMCL CH3CH2 ratio as a compositional marker using 1H MRS at short echo time, and investigated IMCL content and composition during a 28-hour fast in 24 healthy males. Increases in IMCL CH2 relative to the creatine and phosphocreatine resonance (Cr) at 3.0 ppm (an internal standard) correlated with circulating free fatty acid (FA) concentrations, supporting the concept of increased FA influx into IMCL. Significant decreases in IMCL CH3CH2 ratio indicated a less unsaturated IMCL pool after fasting, and this compositional change related inversely to IMCL baseline composition, suggesting a selective efflux of unsaturated shorter-chain FA from the IMCL pool. This novel in vivo evidence reveals IMCL turnover during extended fasting, consistent with the concept of a flexible, responsive myocellular lipid store. There were also differences between soleus and tibialis anterior in basal IMCL composition and in response to fasting. We discuss the potential of this marker for providing insights into normal physiology and mechanisms of disease.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Jejum
/
Músculo Esquelético
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Ácidos Graxos
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Lipólise
Limite:
Adolescent
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Adult
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Humans
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Male
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Middle aged
Idioma:
En
Ano de publicação:
2018
Tipo de documento:
Article