exenatide and Prader-Willi-Syndrome

Prader-Willi syndrome (PWS) is associated with hyperphagia and hyperghrelinemia with major morbidity because of obesity without effective medical treatment targeting hyperphagia. Exenatide (Byetta [synthetic Exendin-4]; AstraZeneca, Wilmington DE) is a GLP-1 receptor agonist which reduces appetite and weight and may be an effective treatment in PWS.. The objective of this study is to determine the effect of a 6-month trial of exenatide on appetite, weight and gut hormones in youth with PWS.. Ten overweight and obese subjects with PWS (13-25 years) were recruited for a 6-month open-label, non-randomized, longitudinal study conducted at Children's Hospital Los Angeles. Exenatide was given using standard diabetes dosing without dietary modifications. Weight, body mass index (BMI), truncal fat, appetite and plasma acylated ghrelin were measured over 6 months. Mixed meal tolerance tests were performed at 0 and 6 months.. Appetite scores significantly decreased from baseline (32.2 ± 8.7) after 1, 3 and 6 moths of treatment (27.5 ± 8.8, 25.4 ± 9.3, and 25.4 ± 7.2 respectively; p = 0.004). Hemoglobin A1c decreased significantly after treatment, but weight, BMI z-score and adiposity did not. There was no significant change in ghrelin.. This is the first longitudinal investigation of the effects of exenatide in subjects with PWS. It was effective in decreasing appetite, without change in weight or BMI in the short term. Larger, controlled, longer-term trials in patients with PWS are needed to confirm the efficacy and safety of exenatide and to evaluate whether its use might induce weight loss when given in conjunction with behavioural modification.

Topics: Adolescent; Adult; Appetite; Body Mass Index; Body Weight; Exenatide; Female; Ghrelin; Humans; Hyperphagia; Incretins; Longitudinal Studies; Male; Obesity; Peptides; Prader-Willi Syndrome; Venoms; Young Adult

Prader-Willi syndrome (PWS) is associated with hyperphagia and obesity, without effective pharmacological treatment. Exenatide, recently developed for treatment of type 2 diabetes, induces appetite suppression and weight loss with common side effects.. The objective of the study was to investigate the initial safety and effectiveness of exenatide in adult PWS subjects compared with obese controls (OBESE).. Eight PWS and 11 OBESE patients underwent standardized meal studies after a single sc injection of 10 μg exenatide or placebo in a single-blinded, crossover design.. Glucose, insulin, C-peptide, glucagon, peptide YY (PYY; total)/PYY (3-36), glucagon-like peptide-1, and ghrelin (total) were measured fasting and postprandially. Appetite and satiety were assessed by visual analog scales. Energy expenditure (EE) was measured by indirect calorimetry. Side effects were screened during and for 24 h after the meal.. PWS and OBESE patients were matched for gender, age, body mass index, and central/total body fat. In both groups, exenatide increased satiety and lowered glucose and insulin levels but increased insulin secretion rate. Side effects were absent in PWS but common in OBESE patients. During the meal, PYY (total) and ghrelin were elevated in PWS patients. Exenatide decreased PYY (total) and glucagon-like peptide-1, whereas ghrelin remained unchanged. Energy expenditure was unchanged by exenatide.. Our pilot study demonstrates that exenatide is well tolerated in PWS patients. It increases satiety independently of measured appetite hormones, exerting glucose lowering, and insulinotropic effects similarly in PWS and OBESE patients. Larger prospective studies should investigate whether chronic exenatide administration will reduce hyperphagia and overweight in PWS patients without side effects.

Topics: Adult; Appetite; Blood Glucose; Cross-Over Studies; Eating; Energy Metabolism; Exenatide; Female; Gastrointestinal Hormones; Homeostasis; Humans; Hunger; Hypoglycemic Agents; Male; Obesity; Peptides; Pilot Projects; Placebos; Prader-Willi Syndrome; Satiety Response; Triglycerides; Venoms

Prader-Willi syndrome (PWS) is a genetic disease characterized by persistent hunger and hyperphagia. The lack of the Snord116 small nucleolar RNA cluster has been identified as the major contributor to PWS symptoms. The Snord116 deletion (Snord116del) mouse model manifested a subset of PWS symptoms including hyperphagia and hyperghrelinemia. In this study, male Snord116del mice were characterized and tested for their acute and chronic responses to anorexic substances related to the ghrelin pathway. In comparison with their wild-type littermates, the food intake rate of Snord116del mice was 14% higher when fed ad libitum, and 32% to 49% higher within 12 hours after fasting. Fasted Snord116del mice were less sensitive to the acute anorexic effect of competitive antagonist [d-Lys(3)]-GHRP6, YIL-781, and reverse agonist [d-Arg(1),d-Phe(5),d-Trp(7,9),Leu(11)]-substance P (SPA) of ghrelin receptor GHS-R. All 3 GHS-R inhibitors failed to inhibit chronic food intake of either Snord116del or wild-type mice due to rapid adaptation. Although fasted Snord116del mice had normal sensitivity to the acute anorexic effect of glucagon-like peptide 1 receptor agonist exenatide, those fed ad libitum required a higher dose and more frequent delivery to achieve ∼15% suppression of long-term food intake in comparison with wild-type mice. Ghrelin, however, is unlikely to be essential for the anorexic effect of exenatide in fed mice, as shown by the fact that exenatide did not reduce ghrelin levels in fed mice and food intake of ghrelin(-/-) mice fed ad libitum could be suppressed by exenatide. In conclusion, this study suggests that GHS-R may not be an effective therapeutic target, and in contrast, exenatide may produce anorexic effect in PWS individuals.

Topics: Analysis of Variance; Animals; Anorexia; Disease Models, Animal; Eating; Exenatide; Fasting; Ghrelin; Humans; Hyperphagia; Hypoglycemic Agents; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Oligopeptides; Peptides; Piperidines; Prader-Willi Syndrome; Quinazolinones; Receptors, Ghrelin; RNA, Small Nucleolar; Substance P; Venoms

We report the use of Exenatide, a GLP-1 agonist, in the management of diabetes mellitus in a 19 year-old female with Prader-Willi syndrome. The beneficial effects of Exenatide in weight reduction and appetite suppression provide a promising strategy for the treatment of obesity and diabetes mellitus in Prader-Willi syndrome.

Topics: Adult; Diabetes Mellitus; Exenatide; Female; Ghrelin; Humans; Peptides; Prader-Willi Syndrome; Venoms; Young Adult

Ghrelin is a potent orexigenic and adipogenic hormone that strongly influences fat deposition and the generation of hunger in obesity. Indeed, hyperghrelinemia appears to promote an increase in food intake as seen in Prader-Willi Syndrome (PWS). Exendin (Ex)-4 is an agonist of the glucagon-like peptide (GLP)-1 receptor (GLP-1r) that has anorexigenic and fat-reducing properties. Here, we report that Ex-4 reduces the levels of ghrelin by up to 74% in fasted rats. These effects are dose dependent and long lasting (up to 8 h), and they can be detected after both central and peripheral administration of Ex-4. Suppression of ghrelin was neither mimicked by GLP-1(7-36)-NH(2) nor blocked by the GLP-1r antagonist Ex-(9-39). Moreover, it was independent of the levels of leptin and insulin. The decrease in ghrelin levels induced by Ex-4 may explain the reduced food intake in fasted rats, justifying the more potent anorexigenic effects of Ex-4 when compared with GLP-1. As well as the potential benefits of Ex-4 in type 2 diabetes, the potent effects of Ex-4 on ghrelin make it tempting to speculate that Ex-4 could offer a therapeutic option for PWS and other syndromes characterized by substantial amounts of circulating ghrelin.

Topics: Animals; Cerebral Ventricles; Exenatide; Fasting; Ghrelin; Humans; Injections, Intraventricular; Kinetics; Male; Peptide Hormones; Peptides; Prader-Willi Syndrome; Rats; Rats, Sprague-Dawley; Venoms