ESPE Abstracts

Background: Prader-Willi syndrome (PWS) is a complex multisystem genetic disorder arising from lack of expression of paternally inherited imprinted genes on chromosome 15q11–q13. Hyperphagia represents one of the most serious symptoms of the PWS, leading to develop premature mortality.

Objective and hypotheses: To compare orexigenic (ghrelin) and anorexigenic factor (brain derived neurotrophic factor (BDNF)) concentration in non-GH-treated obese patients with genetically confirmed PWS with age, sex and BMI-matched obese controls (OC) and lean controls (LC).

Method: Fasting and postprandial levels of plasma ghrelin and serum BDNF during mixed meal testing (370 kcal: 20% protein, 50% carbohydrate and 30% fat) were evaluated in obese children with PWS in comparison with OC and LC. All patients were prepubertal (Tanner 1). Data are reported as medians (interquartile range), Manne–Whitney test was used for between-group.

Results: Fasting ghrelin concentration was significantly higher in 17 (six males: 11 females) PWS children in comparison with 15 (four males: 11 females) OC and ten (four males: six females) LC (1.0 (0.5÷1.0) ng/ml vs 0.23 (0.13÷0.30) ng/ml and 0.23 (0.11÷0.45), P<0.01). Postprandial ghrelin levels on 60 and 120 min (0.75 (0.4÷1.0) vs 0.18 (0.11÷0.31) and 0.17 (0.13÷0.35), P<0.01 and 0.5 (0.4÷1.0) vs 0.16 (0.13÷0.28) ng/ml, P<0.01) were also elevated in PWS. There were no significant differences between 29 PWS (20 males: nine females) and 27 OC (16 males: 11 females) in basal (20.7 (15.77÷24.8) vs 18.49 (12.99÷24.45) ng/ml, P>0.05) and postprandial BDNF levels on 60 and 120 min (22.1 (12.1÷30.27) vs 18.02 (12.97÷25.32), P>0.05 and 24.62 (15.68÷27.75) vs 16.05 (12.29÷22.42) ng/ml, P=0.07). However the concentration of BDNF was significantly higher in PWS compared with 14 LC (12 males: two females) on 0 min (20.7 (15.77÷24.8) vs 14.16 (10.87÷19.34), 60 min (22.1 (12.1÷30.27) vs 13.25 (10.37÷16.02)) and on 120 min (24.63 (15.68÷27.75) vs 13.44 (11.28÷17.4)), P<0.05 respectively.

Conclusion: Fasting and postprandial ghrelin levels were significantly higher in PWS subjects compared to obese and lean controls. The level of BDNF postprandial secretion is significantly higher in PWS patients in contrast to lean controls.