Daily tesamorelin for 26 weeks decreased visceral fat and improved lipid profiles, effects that might be useful in HIV-infected patients who have treatment-associated central fat accumulation. (ClinicalTrials.gov number, NCT00123253 [ClinicalTrials.gov] .).
Prader–Willi syndrome (PWS) is characterized by a switch from failure to thrive to excessive weight gain and hyperphagia in early childhood. Hyperghrelinemia may be involved in the underlying mechanisms of the switch. The purpose of this study is to evaluate acylated ghrelin (AG) and unacylated ghrelin (UAG) levels in PWS and investigate their associations with hyperphagia. This is a cross-sectional clinical study conducted in three PWS expert centers in the Netherlands and France. Levels of AG and UAG and the AG/UAG ratio were determined in 138 patients with PWS (0.2–29.4 years) and compared with 50 age-matched obese subjects (4.3–16.9 years) and 39 healthy controls (0.8–28.6 years). AEBSF was used to inhibit deacylation of AG. As a group, PWS patients had higher AG but similar UAG levels as healthy controls (AG 129.1 vs 82.4 pg/ml, p = 0.016; UAG 135.3 vs 157.3 pg/ml, resp.), resulting in a significantly higher AG/UAG ratio (1.00 vs 0.61, p = 0.001, resp.). Obese subjects had significantly lower AG and UAG levels than PWS and controls (40.3 and 35.3 pg/ml, resp.), but also a high AG/UAG ratio (1.16). The reason for the higher AG/UAG ratio in PWS and obese was, however, completely different, as PWS had a high AG and obese a very low UAG. PWS patients without weight gain or hyperphagia had a similar AG/UAG ratio as age-matched controls, in contrast to those with weight gain and/or hyperphagia who had an elevated AG/UAG ratio. The switch to excessive weight gain in PWS seems to coincide with an increase in the AG/UAG ratio, even prior to the start of hyperphagia.Electronic supplementary materialThe online version of this article (doi:10.1007/s12020-015-0614-x) contains supplementary material, which is available to authorized users.
Objective: The objective of this study was to assess the effects of a continuous overnight infusion of des-acyl ghrelin (DAG) on acylated ghrelin (AG) levels and glucose and insulin responses to a standard breakfast meal (SBM) in eight overweight patients with type 2 diabetes. Furthermore, in the same patients and two additional subjects, the effects of DAG infusion on AG concentrations and insulin sensitivity during a hyperinsulinemic-euglycemic clamp (HEC) were assessed. Research design and methods: A double-blind, placebo-controlled cross-over study design was implemented, using overnight continuous infusions of 3 and 10 mg DAG/kg per h and placebo to study the effects on a SBM. During a HEC, we studied the insulin sensitivity. Results: We observed that, compared with placebo, overnight DAG administration significantly decreased postprandial glucose levels, both during continuous glucose monitoring and at peak serum glucose levels. The degree of improvement in glycemia was correlated with baseline plasma AG concentrations. Concurrently, DAG infusion significantly decreased fasting and postprandial AG levels. During the HEC, 2.5 h of DAG infusion markedly decreased AG levels, and the M-index, a measure of insulin sensitivity, was significantly improved in the six subjects in whom we were able to attain steady-state euglycemia. DAG administration was not accompanied by many side effects when compared with placebo. Conclusions: DAG administration improves glycemic control in obese subjects with type 2 diabetes through the suppression of AG levels. DAG is a good candidate for the development of compounds in the treatment of metabolic disorders or other conditions with a disturbed AG:DAG ratio, such as type 2 diabetes mellitus or Prader-Willi syndrome.
Context and objectivePrader-Willi syndrome (PWS) is characterized by early-onset hyperphagia and increased circulating levels of the orexigenic Acylated Ghrelin (AG) hormone with a relative deficit of Unacylated Ghrelin (UAG). AZP-531, a first-in-class UAG analog, was shown to inhibit the orexigenic effect of AG in animals, to improve glycemic control and decrease body weight in humans. We aimed to investigate the safety and efficacy of AZP-531 in patients with PWS for whom no approved treatment for hyperphagia is currently available.Methods and designMulti-center, randomized, double-blind, placebo-controlled trial. Forty-seven patients with genetically confirmed PWS and evidence of hyperphagia received daily subcutaneous injections of AZP-531 (3 and 4 mg for 50–70 kg and >70 kg body weight, respectively) or matching placebo for 14 days. Assessments included adverse events, vital signs, safety laboratory tests, the Hyperphagia Questionnaire (HQ), patient-reported appetite, body composition and glycemic measures.ResultsAZP-531 was well tolerated. There was a significant improvement with AZP-531 versus placebo in the mean total score, the 9-item score and the severity domain score of the HQ (p < .05). The highest reduction in the total and 9-item scores was observed in AZP-531 subjects with the highest hyperphagia score at baseline. Findings were supported by a reduction in appetite scores observed with AZP-531 only. Body weight did not change in both groups while a significant reduction in waist circumference and fat mass was observed only with AZP-531. AZP-531 significantly decreased post-prandial glucose levels in a baseline glucose dependent fashion.ConclusionsAZP-531 may constitute a new treatment strategy to improve hyperphagia and metabolic issues in patients with PWS. These findings support further investigation in longer-term clinical trials.
TH9507 reduced truncal fat, improved the lipid profile and did not increase glucose levels in HIV-infected patients with central fat accumulation. TH9507 may be a beneficial treatment strategy in this population, but longer-term studies with more patients are needed to determine effects on VAT, treatment durability, and safety.
Treatment with tesamorelin was generally well tolerated and resulted in sustained decreases in VAT and triglycerides over 52 weeks without aggravating glucose. Though effects on VAT are sustained during treatment for 52 weeks, these effects do not last beyond the duration of treatment.
Because of its orexigenic, adipogenic and diabetogenic activities, acylated ghrelin (AG) has emerged as an attractive target for the treatment of obesity and type 2 diabetes. Pharmacological tools have been designed in order to antagonize or block the hormone's activity, or inhibit ghrelin O-acyltransferase (GOAT), the enzyme that catalyzes its acylation. AG antagonists, shown to be potent inhibitors of growth hormone (GH) secretion, were not able to consistently induce the desirable metabolic effects. Some of them, on the contrary, acted as AG agonists. Similarly, AG-blocking agents including Spiegelmers, vaccines, and monoclonal antibodies, gave mixed results. More encouraging yet very preliminary data were obtained with a novel GOAT inhibitor. However, although significant, the observed decrease in circulating AG levels was partial and improvement work remains to be done. Unacylated ghrelin (UAG) and analogs were shown to potently and rapidly inhibit plasma AG levels, and to improve glucose metabolism in addition to displaying beneficial effects on a variety of cells. These data support the rationale for further development of this new therapeutic class in type 2 diabetes and the Prader-Willi syndrome. A development program is underway with AZP-531, a cyclized UAG(6-13) analog with improved pharmacokinetic properties.
AZP-531 was well tolerated in this first-in-human study. Its pharmacokinetic profile, suitable for once-daily dosing, and metabolic effects support further clinical development for T2D.
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