Expression of neuropeptide Y, omentin and visfatin in visceral and subcutaneous adipose tissues in humans: relation to endocrine and clinical parameters

Abstract

Objective: We aimed at exploring the expression of neuropeptide Y (NPY), omentin and visfatin in adipose tissues of adults along with clinical parameters and hormones.

Methods: We included 168 adult patients (31 surgical obese patients and 31 surgical controls, 76 non-surgical obese patients, 30 non-surgical controls). We measured plasma NPY (by radioimmunoassay), cortisol (with an electrochemiluminescence immunoassay) and urinary cortisol metabolites (by gas chromatography/mass spectrometry). Expression of NPY, omentin and visfatin in subcutaneous and visceral adipose tissue specimens of the surgical patients was quantified using real-time PCR.

Results: NPY was detectable in adipose tissue specimens and, like plasma NPY concentrations, comparable between groups. Omentin gene expression was higher in visceral than in subcutaneous adipose tissues (p < 0.0001). Visfatin expression was lower in the subcutaneous tissue of obese patients compared with controls (p < 0.05). Cortisol was lower in obese adults compared with controls (136.5 +/- 74.1 vs. 162.2 +/- 56.1 ng/ml; p < 0.05), cortisol metabolites were comparable between groups.

Conclusion: In our obese adults, plasma NPY levels and the glucocorticoid measures were not elevated. Even though the expression of NPY, omentin and visfatin was comparable between obese individuals and controls, we have to consider differences in the total production rate of adipose tissue-derived factors.

Fig. 1

NPY gene expression normalized to β-actin for reference in visceral (vis) and subcutaneous (sc) adipose tissue specimens of adult patients (LAGB = gastric banding group (n = 31); Co = controls (n = 31)); no significant differences between groups.

Fig. 2

Omentin gene expression normalized to β-actin for reference in visceral (vis) and subcutaneous (sc) adipose tissue specimens of adult patients (LAGB = gastric banding group (n = 31); Co = controls (n = 31)). ****p < 0.0001 for the omentin gene expression in visceral compared with subcutaneous adipose tissues. Omentin gene expression was slightly, but not significantly decreased in visceral adipose tissues of obese patients compared with controls.

Fig. 3

Visfatin gene expression normalized to β-actin for reference in visceral (vis) and subcutaneous (sc) adipose tissue specimens of adult patients (LAGB = gastric banding group (n = 31); Co = controls (n = 31)). Visfatin gene expression was decreased in subcutaneous adipose tissues of obese patients compared with controls (*p < 0.05).