Stimulating amyloid-β clearance in cerebral amyloid angiopathy with low-sodium oxybate and/or non-invasive vagus nerve stimulation (Clear-Brain): study protocol for a randomised pre-post trial
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Sanne E Schriemer1, Lydiane Hirschler2, Ellis S van Etten3
1Department of Neurology, Leiden University Medical Center, Leiden, The Netherlands s.e.schriemer@lumc.nl.
Introduction:
Cerebral amyloid angiopathy (CAA) is caused by the accumulation of amyloid-beta (Aβ) in the cerebrovasculature. The glymphatic system is thought to be involved in the clearance of cerebral waste products, including Aβ. Stimulation of the glymphatic system through enhancing deep sleep with low-sodium oxybate (LXB) or inhibition of cortical spreading depolarisations via non-invasive vagus nerve stimulation (nVNS) could potentially increase clearance of Aβ and hence improve disease course.
Methods And Analysis:
We will perform a pre-post trial to assess whether treatment with LXB, nVNS or a combination of both interventions can enhance the clearance of Aβ in patients with CAA. A total of 60 participants, 30 with sporadic CAA and 30 with Dutch-type CAA, will be randomly assigned to receive either LXB, nVNS or both interventions, resulting in three groups (20 in each group: LXB, nVNS and both). The study spans 6 months, comprising a 3-month observational phase and a 3-month intervention phase. The primary outcome measure will be the morning levels of Aβ40 and Aβ42 in cerebrospinal fluid (CSF) before and after the intervention. We will assess possible disease progression with (non-)haemorrhagic imaging markers on 7-Tesla MRI at baseline, before and after intervention, as a secondary outcome. Additionally, the activity of the glymphatic system by means of fluid dynamics will be assessed with CSF-Selective T2-weighted Readout with Acceleration and Mobility encoding (CSF-STREAM) on 7-Tesla MRI.
Ethics And Dissemination:
The study was reviewed and approved by the Medical Research Ethics Committee Leiden The Hague Delft (P23.100) on 8 April 2024. The first participant was enrolled on 27 March 2025. Study results will be published in peer-reviewed journals and presented at scientific conferences. Additionally, study updates and results will be shared with participants via our newsletter twice a year.
Trial Registration:
EU CT number 2023-5 06 128-10-00, Universal Trial Number U1111-1295-1113, ClinicalTrials.gov NCT06421532.
