Fast urine metabolomics for the assessment of Zopiclone effects on insomnia

Insomnia is a common symptom of many diseases and is closely associated with neurodegenerative diseases. Zopiclone is one of several clinical hypnotics for treating insomnia. However, some patients are sensitive to this drug treatment, whereas others are not, and the underlying mechanisms remain unclear, causing confusion for making therapeutic regimens and prolong the course of the disease. In present work, we developed a fast urine metabolomics' method for evaluating the sensitivity of insomnia patients to Zopiclone treatment. Firstly, we extracted urine metabolome using methanol-water solutions of different ratios. Secondly, the extracts were either directly injected into LC-MS analysis or dried and resuspended using methanol-water solutions of different concentrations for LC-MS analysis. Then, the total abundance and chromatographic behaviors of urine metabolome from different extraction methods were compared with each other. The optimal extraction method is to mix 50 microl of urine with an equal volume of methanol and 150 microl of water for LC-MS analysis. Finally, the developed method was applied to a metabolomics study of urine from patients with insomnia to evaluate the effectiveness of Zopiclone in treating insomnia. The results showed that there were significant statistical differences in the levels of acylcarnitines, β-hydroxybutyrate (BHB), 4-hydroxybutyric acid (GHB), 3-hydroxyisovaleric acid, citrate, leucine, isoleucine, and valine between the sensitive and insensitive groups treated with Zopiclone. Furthermore, alterations in levels of GHB, valine, and isoleucine were closely correlated with Pittsburgh Sleep Quality Index (PSQI) scores, which may be potential biomarkers for assessing the sensitivity of insomnia patients to Zopiclone treatment, and guiding therapy adjustment.