ADIPONECTIN AND PEROXISOME PROLIFERATOR-ACTIVATED RECEPTOR γ EXPRESSION IN SUBCUTANEOUS AND OMENTAL ADIPOSE TISSUE IN CHILDREN

Abstract

INTRODUCTION: Adiponectin is an adipocyte-specific protein with insulin-sensitizing properties. Peroxisome proliferator-activated receptor γ (PPARγ) may be involved in its gene transcription. OBJECTIVE: The aim of this study was to compare the expression levels of the genes that encode adiponectin and PPARγ in subcutaneous and omental adipose tissue in children in relation to age and anthropometric variables. METHODS: Paired biopsies (from subcutaneous and omental adipose tissue) were obtained from 53 children (age: 0.2–14.0 years; BMI: 12.5–25.8 kg/m2). Messenger RNA (mRNA) levels of adiponectin and PPARγ were measured by using reverse-transcription and quantitative real-time polymerase chain reaction. RESULTS: Adiponectin mRNA levels in adipose tissue were positively associated with PPARγ mRNA levels in children (subcutaneous adipose: r = 0.73, P < .001; omental adipose: r = 0.78, P < .001). In overweight children, the median adiponectin mRNA level was lower in omental adipose tissue (odds ratio: 0.51 [95% confidence interval: 0.1–2.17]) compared with subcutaneous adipose tissue (odds ratio: 1.29 [95% confidence interval: 0.16–5.08]) (P = .032) but not in normal-weight children (P = .54), and the difference remained significant after adjustment for age (P = .045). CONCLUSIONS: The close association between adiponectin and PPARγ expression supports the hypothesis that PPARγ is involved in adiponectin gene regulation. The fact that adiponectin expression was decreased in omental adipose tissue relative to subcutaneous adipose tissue in overweight children suggests that a risk of insulin resistance may be present in childhood, which allows such resistance to develop after a relatively short duration of overweight.