Adipocytes IGFBP-2 expression in prepubertal obese children.
Aims of the study were to measure insulin-like growth factor-binding protein-2 (IGFBP-2) expression by abdominal subcutaneous adipocytes and to assess the relationship between IGFBP-2 expression, circulating IGFBP-2, obesity, and insulin sensitivity in obese children. Thirty-eight obese children were recruited. Insulin sensitivity was assessed by intravenous glucose tolerance test and body composition by total-body dual-energy X-ray absorptiometry. Serum free and total IGF-I, IGFBP-2, adiponectin, and leptin were measured. Relative quantification of IGFBP-2 mRNA by subcutaneous adipose tissue biopsies was obtained using real-time PCR. Circulating IGFBP-2 was positively associated with insulin sensitivity, in agreement with previous studies. IGFBP-2 expression was associated with fat mass percentage (r = 0.656; P < 0.02), insulin sensitivity (r = -0.604; P < 0.05), free IGF-I (r = 0.646; P < 0.05), and leptin (r = 0.603; P < 0.05), but not with circulating IGFBP-2 (r = 0.003, P = ns). The association between IGFBP-2 expression and adiposity (r = 0.648; P < 0.05) was independent of insulin sensitivity (covariate). In conclusion, circulating IGFBP-2 was positively associated with insulin sensitivity. IGFBP-2 was expressed by subcutaneous abdominal adipocytes of obese children and increased with adiposity, independently from the level of insulin sensitivity. IGFBP-2 expression may potentially be one of the local mechanisms used by adipocytes to limit further fat gain.
Regional Centre for Juvenile Diabetes, Section of Obesity and Clinical Nutrition, Department of Mother and Child, Biology-Genetics, University of Verona, Verona, Italy. claudio.maffeis@univr.it
Maffeis
M
Claudio
Ficial
F
Benjamim
Bonadonna
B
Riccardo
Corradi
C
Massimiliano
Bertoldo
B
Francesco
Cominacini
C
Luciano
D017667:Adipocytes / Q000378:metabolism*; D002648:Child; D005260:Female; D006801:Humans; D007333:Insulin Resistance; D018971:Insulin-Like Growth Factor Binding Protein 2 / Q000097:blood / Q000378:metabolism*; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D020738:Leptin / Q000097:blood; D008297:Male; D009765:Obesity / Q000097:blood*; D050151:Subcutaneous Fat / Q000166:cytology / Q000378:metabolism*
D018971:Insulin-Like Growth Factor Binding Protein 2; D020738:Leptin; D007334:Insulin-Like Growth Factor I