Relative contribution of intramyocellular lipid to whole-body fat oxidation is reduced with age but subsarcolemmal lipid accumulation and insulin resistance are only associated with overweight individuals

Insulin resistance is closely related to intramyocellular lipid (IMCL) accumulation, and both are associated with increasing age. It remains to be determined to what extent perturbations in IMCL metabolism are related to the aging process per se. On two separate occasions, whole-body and muscle insu...

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Main Authors: Chee, Carolyn, Shannon, Chris E., Burns, Aisling, Selby, Anna L., Wilkinson, Daniel, Smith, Kenneth, Greenhaff, Paul L., Stephens, Francis B.
Format: Article
Published: American Diabetes Association 2016
Online Access:https://eprints.nottingham.ac.uk/35101/
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author Chee, Carolyn
Shannon, Chris E.
Burns, Aisling
Selby, Anna L.
Wilkinson, Daniel
Smith, Kenneth
Greenhaff, Paul L.
Stephens, Francis B.
author_facet Chee, Carolyn
Shannon, Chris E.
Burns, Aisling
Selby, Anna L.
Wilkinson, Daniel
Smith, Kenneth
Greenhaff, Paul L.
Stephens, Francis B.
author_sort Chee, Carolyn
building Nottingham Research Data Repository
collection Online Access
description Insulin resistance is closely related to intramyocellular lipid (IMCL) accumulation, and both are associated with increasing age. It remains to be determined to what extent perturbations in IMCL metabolism are related to the aging process per se. On two separate occasions, whole-body and muscle insulin sensitivity (euglycemic-hyperinsulinemic clamp with 2-deoxyglucose) and fat utilization during 1 h of exercise at 50% VO2max ([U-13C]palmitate infusion combined with electron microscopy of IMCL) were determined in young lean (YL), old lean (OL), and old overweight (OO) males. OL displayed IMCL content and insulin sensitivity comparable with those in YL, whereas OO were markedly insulin resistant and had more than twofold greater IMCL in the subsarcolemmal (SSL) region. Indeed, whereas the plasma free fatty acid Ra and Rd were twice those of YL in both OL and OO, SSL area only increased during exercise in OO. Thus, skeletal muscle insulin resistance and lipid accumulation often observed in older individuals are likely due to lifestyle factors rather than inherent aging of skeletal muscle as usually reported. However, age per se appears to cause exacerbated adipose tissue lipolysis, suggesting that strategies to reduce muscle lipid delivery and improve adipose tissue function may be warranted in older overweight individuals.
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spelling nottingham-351012020-05-04T20:03:06Z https://eprints.nottingham.ac.uk/35101/ Relative contribution of intramyocellular lipid to whole-body fat oxidation is reduced with age but subsarcolemmal lipid accumulation and insulin resistance are only associated with overweight individuals Chee, Carolyn Shannon, Chris E. Burns, Aisling Selby, Anna L. Wilkinson, Daniel Smith, Kenneth Greenhaff, Paul L. Stephens, Francis B. Insulin resistance is closely related to intramyocellular lipid (IMCL) accumulation, and both are associated with increasing age. It remains to be determined to what extent perturbations in IMCL metabolism are related to the aging process per se. On two separate occasions, whole-body and muscle insulin sensitivity (euglycemic-hyperinsulinemic clamp with 2-deoxyglucose) and fat utilization during 1 h of exercise at 50% VO2max ([U-13C]palmitate infusion combined with electron microscopy of IMCL) were determined in young lean (YL), old lean (OL), and old overweight (OO) males. OL displayed IMCL content and insulin sensitivity comparable with those in YL, whereas OO were markedly insulin resistant and had more than twofold greater IMCL in the subsarcolemmal (SSL) region. Indeed, whereas the plasma free fatty acid Ra and Rd were twice those of YL in both OL and OO, SSL area only increased during exercise in OO. Thus, skeletal muscle insulin resistance and lipid accumulation often observed in older individuals are likely due to lifestyle factors rather than inherent aging of skeletal muscle as usually reported. However, age per se appears to cause exacerbated adipose tissue lipolysis, suggesting that strategies to reduce muscle lipid delivery and improve adipose tissue function may be warranted in older overweight individuals. American Diabetes Association 2016-04 Article PeerReviewed Chee, Carolyn, Shannon, Chris E., Burns, Aisling, Selby, Anna L., Wilkinson, Daniel, Smith, Kenneth, Greenhaff, Paul L. and Stephens, Francis B. (2016) Relative contribution of intramyocellular lipid to whole-body fat oxidation is reduced with age but subsarcolemmal lipid accumulation and insulin resistance are only associated with overweight individuals. Diabetes, 65 (4). pp. 840-850. ISSN 1939-327X
spellingShingle Chee, Carolyn
Shannon, Chris E.
Burns, Aisling
Selby, Anna L.
Wilkinson, Daniel
Smith, Kenneth
Greenhaff, Paul L.
Stephens, Francis B.
Relative contribution of intramyocellular lipid to whole-body fat oxidation is reduced with age but subsarcolemmal lipid accumulation and insulin resistance are only associated with overweight individuals
title Relative contribution of intramyocellular lipid to whole-body fat oxidation is reduced with age but subsarcolemmal lipid accumulation and insulin resistance are only associated with overweight individuals
title_full Relative contribution of intramyocellular lipid to whole-body fat oxidation is reduced with age but subsarcolemmal lipid accumulation and insulin resistance are only associated with overweight individuals
title_fullStr Relative contribution of intramyocellular lipid to whole-body fat oxidation is reduced with age but subsarcolemmal lipid accumulation and insulin resistance are only associated with overweight individuals
title_full_unstemmed Relative contribution of intramyocellular lipid to whole-body fat oxidation is reduced with age but subsarcolemmal lipid accumulation and insulin resistance are only associated with overweight individuals
title_short Relative contribution of intramyocellular lipid to whole-body fat oxidation is reduced with age but subsarcolemmal lipid accumulation and insulin resistance are only associated with overweight individuals
title_sort relative contribution of intramyocellular lipid to whole-body fat oxidation is reduced with age but subsarcolemmal lipid accumulation and insulin resistance are only associated with overweight individuals
url https://eprints.nottingham.ac.uk/35101/