0748 A Novel, Non-Pharmacological Treatment Option for Patients With Idiopathic Hypersomnia

Introduction

There is some evidence suggesting that patients with hypersomnia have delayed circadian timing, which could explain, at least in part, the excessive sleepiness and impaired daytime performance experienced by these individuals. This study investigated the effects of bright light treatment on improving daytime alertness in patients with idiopathic hypersomnia.

Methods

Participants were scheduled to two in-laboratory sessions (baseline and treatment) consisting of overnight sleep monitoring (polysomnography) followed by maintenance of wakefulness tests (MWT) and performance testing (10-min psychomotor vigilance task (PVT)). MWTs were performed at 10:00, 12:00, 14:00 and 16:00 and PVTs were performed at 11:00, 13:00, 15:00 and 15:00. In-laboratory sessions were separated by a two-week at-home treatment period during which participants were instructed to use commercially available light devices for 30-60 min each morning. Participants also completed the Pittsburgh Sleep Quality Index (PSQI) and Epworth Sleepiness Scale (ESS) at baseline and after treatment. Paired t-tests were performed to assess differences in sleep architecture, sleep quality, performance (lapses; reaction time >500ms) and alertness (MWT mean sleep latency) between baseline and treatment.

Results

To date, three participants (2 male) aged 62.7±13.2 (mean±SD) years have completed the study. Lapses (baseline: 17.9±11.9; treatment: 6.3±5.4), ESS (baseline: 17.3±3.1; treatment 12.3±6.8) and PSQI (baseline: 7.7±3.8; treatment: 4.0±1.0) all improved with light treatment, although this did not reach statistical significance. There were no statistical differences between baseline and treatment with regards to sleep architecture or mean sleep latency.

Conclusion

Although preliminary, results suggest that bright light treatment may improve subjective sleepiness, subjective sleep quality and performance. There was some variability between individuals, indicating that this treatment may not offer the same benefits to all patients. Although ongoing, this study suggests that light therapy could be used as an alternative, non-pharmacological treatment option to improve waking functions and sleepiness in hypersomnia patients.

Support

This project is supported by a Hunter Medical Research Institute Research Project Grant

Structure-based design of an osteoclast-selective, nonpeptide src homology 2 inhibitor with in vivo antiresorptive activity

Targeted disruption of the pp60(src) (Src) gene has implicated this tyrosine kinase in osteoclast-mediated bone resorption and as a therapeutic target for the treatment of osteoporosis and other bone-related diseases. Herein we describe the discovery of a nonpeptide inhibitor (AP22408) of Src that demonstrates in vivo antiresorptive activity. Based on a cocrystal structure of the noncatalytic Src homology 2 (SH2) domain of Src complexed with citrate [in the phosphotyrosine (pTyr) binding pocket], we designed 3',4'-diphosphonophenylalanine (Dpp) as a pTyr mimic. In addition to its design to bind Src SH2, the Dpp moiety exhibits bone-targeting properties that confer osteoclast selectivity, hence minimizing possible undesired effects on other cells that have Src-dependent activities. The chemical structure AP22408 also illustrates a bicyclic template to replace the post-pTyr sequence of cognate Src SH2 phosphopeptides such as Ac-pTyr-Glu-Glu-Ile (1). An x-ray structure of AP22408 complexed with Lck (S164C) SH2 confirmed molecular interactions of both the Dpp and bicyclic template of AP22408 as predicted from molecular modeling. Relative to the cognate phosphopeptide, AP22408 exhibits significantly increased Src SH2 binding affinity (IC(50) = 0.30 microM for AP22408 and 5.5 microM for 1). Furthermore, AP22408 inhibits rabbit osteoclast-mediated resorption of dentine in a cellular assay, exhibits bone-targeting properties based on a hydroxyapatite adsorption assay, and demonstrates in vivo antiresorptive activity in a parathyroid hormone-induced rat model.