Postprandial interleukin-6 release from skeletal muscle in men with impaired glucose tolerance can be reduced by weight loss.
BACKGROUND
Obesity and type 2 diabetes mellitus are associated with increased levels of IL-6, a marker of inflammation.


OBJECTIVE
This study addressed the question of whether IL-6 was released from skeletal muscle after a high-fat meal in men with impaired glucose tolerance (IGT), a prediabetic state, and whether IL-6 release could be reduced by weight loss.


METHODS
Skeletal muscle metabolism was studied in men with IGT (n = 11) and compared with men with normal glucose tolerance (NGT, n = 9), matched for body mass index and age. IL-6 flux over skeletal muscle was measured with the forearm model. Eight IGT men were willing to participate in a 12-wk weight loss program and were tested again.


RESULTS
IL-6, but not C-reactive protein or TNF-alpha receptor 1 and 2, was released by skeletal muscle. Muscle IL-6 release was higher in IGT than in NGT during fasting (IGT = 2.26 +/- 1.89 vs. NGT = 0.87 +/- 0.48 fmol x 100 ml tissue(-1) x min(-1), P = 0.04) and after a meal (mean area under the curve per minute: IGT = 3.48 +/- 2.63 vs. NGT = 1.37 +/- 0.75 fmol x 100 ml tissue(-1) x min(-1); P = 0.03). In the IGT men, body weight loss resulted in a decrease of postprandial IL-6 release from skeletal muscle (-52%; P = 0.04), reaching levels of the obese, NGT controls.


CONCLUSIONS
The present data suggest that a high-fat meal can evoke IL-6 release from muscle and that the IL-6 release is a consequence rather than a cause of the obese, insulin-resistant, and/or IGT state.
Corpeleijn
Eva
E
Department of Human Biology, Nutrition and Toxicology Research Institute, Maastricht University, P.O. Box 616, 6200 MD Maastricht, The Netherlands. E.Corpeleijn@hb.unimaas.nl
Saris
Wim H M
WH
Jansen
Eugène H J M
EH
Roekaerts
Paul M H J
PM
Feskens
Edith J M
EJ
Blaak
Ellen E
EE
D000368:Aged; D015308:Anaerobic Threshold / Q000502:physiology; D015415:Biomarkers; D001786:Blood Glucose / Q000378:metabolism; D001823:Body Composition / Q000502:physiology; D001835:Body Weight / Q000502:physiology; D004041:Dietary Fats / Q000494:pharmacology; D005230:Fatty Acids, Nonesterified / Q000097:blood; D005260:Female; D018149:Glucose Intolerance / Q000378:metabolism*; D006801:Humans; D007328:Insulin / Q000097:blood; D007333:Insulin Resistance / Q000502:physiology; D015850:Interleukin-6 / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000378:metabolism*; D009765:Obesity / Q000378:metabolism; D019518:Postprandial Period / Q000502:physiology*; D015431:Weight Loss / Q000502:physiology*
D015415:Biomarkers; D001786:Blood Glucose; D004041:Dietary Fats; D005230:Fatty Acids, Nonesterified; D007328:Insulin; D015850:Interleukin-6