Background: To determine how leptin and ghrelin are expressed in the adipose tissues of obese adults undergoing gastric banding (LAGB), and to correlate tissue expression with serum concentrations and parameters of the metabolic syndrome.
Materials and methods: A cross-sectional analysis of 92 patients: 61 obese patients with a body mass index (BMI) 49.2 +/- 1 kg m(-2) received LAGB, 20 patients underwent band exchange (BMI, 36.6 +/- 1.4 kg m(-2)) and 11 adult patients (BMI, 24.3 +/- 0.6 kg m(-2)) with fundoplication served as controls. Clinical data such as BMI and blood pressure were evaluated along with subcutaneous and visceral adipose tissue gene expression and fasting levels of leptin and ghrelin. Tissue transcripts were measured using real-time PCR, serum protein concentrations radio-immunologically.
Results: Leptin gene expression was highest in the primary LAGB group and more pronounced in subcutaneous fat in both sexes (P < 0.0001). Serum leptin concentrations were highest in the LAGB group (P < 0.001), whereby women exhibited higher serum levels than men. Leptin concentrations correlated positively to expression in subcutaneous fat (P < 0.0001), and leptin expression was also correlated to BMI and systolic blood pressure. We detected ghrelin gene expression in both types of fat. The ghrelin mRNA amounts in adipose tissues were similar in both sexes and comparable within groups; serum concentrations were lower in patients with primary LAGB than in controls (P < 0.05).
Conclusions: Human adipose tissue expression of leptin is weight-course dependent and ghrelin is constitutional. Serum levels of leptin, but not of ghrelin, are indicative of an adaptive pattern of local gene expression in obese subjects undergoing weight reduction.