Serum visfatin and vaspin levels in prepubertal children: effect of obesity and weight loss after behavior modifications on their secretion and relationship with glucose metabolism.

Abstract

To investigate the impact of obesity, weight loss and oral glucose ingestion on serum visfatin and vaspin levels in prepubertal children. A total of 100 prepubertal obese Caucasian children (OB) and 42 controls (C) were studied. The OB group was studied at baseline and after moderate (n=46) and extensive (n=14) body mass index (BMI) reduction by conservative treatment, undergoing body composition studies (dual-energy X-ray absorptiometry) and oral glucose tolerance tests (OGTTs). Serum visfatin and vaspin levels were studied throughout the OGTT, as were their relationships with insulin, leptin, leptin soluble receptor (sOB-R), adiponectin (total and high molecular weight), resistin, interleukin-6 (IL-6) and tumor necrosis factor-α levels at every time point. OB had higher visfatin (P<0.001), but similar vaspin than C. BMI reduction decreased visfatin levels (P<0.001), with BMI, waist circumference and the surrogate markers of body fat (leptin and sOB-R) showing significant correlations (P<0.05) with this peptide, but not with vaspin. Visfatin and vaspin decreased during the OGTT (P<0.001). Weight reduction did not alter visfatin dynamics in the OGTT, but decreased the area under the curve (AUC) for vaspin (P<0.001), with a correlation between the AUCs for vaspin and insulin after weight loss (P<0.05). Visfatin levels were positively correlated with resistin and IL-6, after controlling for BMI and HOMA (homeostatic model assessment) index at every time point in the study. Serum visfatin, but not vaspin, levels are influenced by body fat content in obese children, whereas both adipokines are modulated by glucose intake in a BMI-dependent manner.