Effect of weight reduction on serum ghrelin and TNFalpha concentrations in obese women.

Abstract

Background: Ghrelin causes weight gain by increasing food intake in rodents. Tumor necrosis factor alpha (TNFalpha) is produced by adipose tissue, modulates its metabolism and stimulates catabolic processes. The aim of our study was to evaluate whether weight loss treatment modulates serum concentrations of TNFalpha and ghrelin in obese women. Methods: The study groups included 46 women: 35 obese patients and 11 controls. Serum concentrations of ghrelin and TNFalpha were measured by ELISA before and after a 3-month weight reduction treatment that consisted of a 1000 kcal/day diet and physical exercises. Body composition was determined by impedance analysis using Bodystat. Results: There were no differences in plasma ghrelin concentrations between obese patients and controls. TNFalpha serum levels were higher in obese patients than in controls (p=0.000). The mean weight loss over the 3-month treatment period was 8.7+/-4.5 kg. Following weight loss, serum ghrelin concentration increased significantly (66.3+/-13.7 vs. 73.7+/-14.8 pg/ml; p=0.002) and TNFalpha concentrations decreased significantly (6.9+/-2.6 vs. 5.2+/-1.5 pg/ml; p=0.002). Ghrelin did not show a correlation with weight or percentage of body fat. There was a positive correlation between the increase in ghrelin and the decrease in body fat percentage during weight loss (p=0.002). Conclusion: The increase in serum ghrelin and the decrease in serum TNFalpha, as observed after weight reduction treatment in obese subjects, may constitute a counter-regulatory mechanism preventing further weight loss.