Low adiponectin levels in adolescent obesity: a marker of increased intramyocellular lipid accumulation.
We examined the impact of adolescent obesity on circulating adiponectin levels and the relationship between adiponectin and insulin sensitivity, intramyocellular (IMCL) lipid content, plasma triglycerides, and free fatty acids. Plasma adiponectin levels were measured in 8 nonobese (percentage fat, 18 +/- 1.8) and 14 obese adolescents (percentage fat, 41 +/- 1.6). Insulin sensitivity was assessed by the euglycemic-hyperinsulinemic clamp. Intramuscular lipid content was quantified using (1)H-nuclear magnetic resonance spectroscopy, and abdominal fat distribution by magnetic resonance imaging. Adiponectin levels were lower in obese adolescents (9.2 +/- 1 microg/ml, P < 0.001) and were positively related to insulin sensitivity in all subjects (r = 0.531, P < 0.02). Strong inverse relationships were found between adiponectin and triglyceride levels (r = -0.80, P < 0.001) and IMCL (r = -0.73, P < 0.001). Triglycerides (partial r(2) = 0.52; P < 0.0002) and IMCL (partial r(2) = 0.10; P < 0.05) were the most significant predictors of adiponectin levels, explaining 62% of the variation. In conclusion, plasma adiponectin levels are reduced in adolescent obesity and related to insulin resistance, independent of total body fat and central adiposity. There is a strong relationship between adiponectin and IMCL lipid content in this pediatric population. The putative modulatory effects of adiponectin on insulin sensitivity may, in part, be mediated via its effects on IMCL lipid content.
Department of Pediatrics, Yale University School of Medicine, New Haven, Connecticut 06520, USA.
Ram
R
Weiss
Sylvie
S
Dufour
Aida
A
Groszmann
Kitt
K
Petersen
James
J
Dziura
Sara E
SE
Taksali
Gerald
G
Shulman
Sonia
S
Caprio
D000005:Abdomen; D052242:Adiponectin; D000273:Adipose Tissue; D000293:Adolescent; D015415:Biomarkers / Q000097:blood*; D001823:Body Composition; D005260:Female; D015309:Glucose Clamp Technique; D006801:Humans; D007328:Insulin / Q000097:blood; D007333:Insulin Resistance; D036341:Intercellular Signaling Peptides and Proteins; D008055:Lipids / Q000032:analysis*; D008279:Magnetic Resonance Imaging; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D018482:Muscle, Skeletal / Q000737:chemistry*; D009765:Obesity / Q000097:blood*; D011506:Proteins / Q000032:analysis*; D014280:Triglycerides / Q000032:analysis / Q000097:blood
D052242:Adiponectin; D015415:Biomarkers; D007328:Insulin; D036341:Intercellular Signaling Peptides and Proteins; D008055:Lipids; D011506:Proteins; D014280:Triglycerides