Objective: A growing body of studies has demonstrated the inverse relationship between DHEA-sulfate (DHEA-S) and the pathological alterations associated with the metabolic syndrome. However, the mechanism by which DHEA-S treatment operates has not been elucidated completely. Adiponectin, an adipose-specific protein, is thought to have anti-diabetic and anti-atherosclerotic properties. Because fat depots differ in the impact of their relationship with the undesirable consequences of obesity, the aim of the present study was to investigate the effect of DHEA-S on adiponectin expression in both s.c. and visceral tissues in a morbidly obese population.
Design and methods: We studied the in vitro expression of the adiponectin gene from paired biopsies of human visceral and s.c. adipose tissue, obtained from men and women (body mass index = 48.68± 7.43 kg/m2). Adipocytes were incubated for 24 h with or without DHEA-S. Adiponectin mRNA was measured by reverse transcription-quantitative PCR.
Results: In this population, DHEA-S plasma values were 141 ± 105 μg/100 ml. Serum adiponectin values were under normal ranges. In basal conditions, s.c. tissue expressed higher amounts (58%) of adiponectin mRNA than visceral tissue (P = 0.027). Adiponectin expression was differentially regulated in the two depots by DHEA-S. There was a significant increase in adiponectin expression specifically in the visceral tissue (P = 0.020), but no significant effect of DHEA-S on the s.c. tissue (P = 0.738).
Conclusions: In the present study, for the first time in humans, we have shown that DHEA-S treatment is a strong upregulator of adiponectin gene expression in omental adipocytes, suggesting that the positive effects observed by DHEA-S treatment in humans suffering from metabolic syndrome could be exerted through overexpression of adiponectin in the visceral depot.