title: Protocol for intraoperative assessment of the human cerebrovascular glycocalyx.
abstract: Adequate functioning of the blood-brain barrier (BBB) is important for brain homoeostasis and normal neuronal function. Disruption of the BBB has been described in several neurological diseases. Recent reports suggest that an increased permeability of the BBB also contributes to increased seizure susceptibility in patients with epilepsy. The endothelial glycocalyx is coating the luminal side of the endothelium and can be considered as the first barrier of the BBB. We hypothesise that an altered glycocalyx thickness plays a role in the aetiology of temporal lobe epilepsy (TLE), the most common type of epilepsy. Here, we propose a protocol that allows intraoperative assessment of the cerebrovascular glycocalyx thickness in patients with TLE and assess whether its thickness is decreased in patients with TLE when compared with controls.
  
  
  
  This protocol is designed as a prospective observational case-control study in patients who undergo resective brain surgery as treatment for TLE. Control subjects are patients without a history of epileptic seizures, who undergo a craniotomy or burr hole surgery for other indications. Intraoperative glycocalyx thickness measurements of sublingual, cortical and hippocampal microcirculation are performed by video microscopy using sidestream dark-field imaging. Demographic details, seizure characteristics, epilepsy risk factors, intraoperative haemodynamic parameters and histopathological evaluation are additionally recorded.
  
  
  
  This protocol has been ethically approved by the local medical ethical committee (ID: NL51594.068.14) and complies with the Declaration of Helsinki and principles of Good Clinical Practice. Informed consent is obtained before study enrolment and only coded data will be stored in a secured database, enabling an audit trail. Results will be submitted to international peer-reviewed journals and presented at international conferences.
  
  
  
  NTR5568.
authors.affiliation: Department of Neurosurgery, School for Mental Health and Neuroscience, Maastricht University Medical Center, Maastricht, The Netherlands.
authors.forename: R H L
authors.initials: RH
authors.lastname: Haeren
authors.affiliation: Department of Physiology, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, The Netherlands.
authors.forename: H
authors.initials: H
authors.lastname: Vink
authors.affiliation: Department of Neurology, Cardiovascular Research Institute Maastricht, Maastricht University Medical Center, Maastricht, The Netherlands.
authors.forename: J
authors.initials: J
authors.lastname: Staals
authors.affiliation: Department of Genetics & Cell Biology, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, The Netherlands.|Institute for Molecular Cardiovascular Research, IMCAR, Universitätsklinikum, Aachen University, Aachen, Germany.
authors.forename: M A M J
authors.initials: MA
authors.lastname: van Zandvoort
authors.affiliation: Department of Neurosurgery, School for Mental Health and Neuroscience, Maastricht University Medical Center, Maastricht, The Netherlands.|Academic Center for Epileptology, Maastricht University Medical Center and Kempenhaeghe, Maastricht/Heeze, The Netherlands.
authors.forename: J
authors.initials: J
authors.lastname: Dings
authors.affiliation: Department of Neurosurgery, School for Mental Health and Neuroscience, Maastricht University Medical Center, Maastricht, The Netherlands.|Academic Center for Epileptology, Maastricht University Medical Center and Kempenhaeghe, Maastricht/Heeze, The Netherlands.
authors.forename: J J
authors.initials: JJ
authors.lastname: van Overbeeke
authors.affiliation: Department of Neurosurgery, School for Mental Health and Neuroscience, Maastricht University Medical Center, Maastricht, The Netherlands.|Academic Center for Epileptology, Maastricht University Medical Center and Kempenhaeghe, Maastricht/Heeze, The Netherlands.
authors.forename: G
authors.initials: G
authors.lastname: Hoogland
authors.affiliation: Department of Neurosurgery, School for Mental Health and Neuroscience, Maastricht University Medical Center, Maastricht, The Netherlands.|Department of Neurosurgery, Zuyderland Medical Center, Heerlen, The Netherlands.
authors.forename: K
authors.initials: K
authors.lastname: Rijkers
authors.affiliation: Department of Neurosurgery, School for Mental Health and Neuroscience, Maastricht University Medical Center, Maastricht, The Netherlands.|Academic Center for Epileptology, Maastricht University Medical Center and Kempenhaeghe, Maastricht/Heeze, The Netherlands.
authors.forename: O E M G
authors.initials: OE
authors.lastname: Schijns
mesh_terms: D000293:Adolescent; D000328:Adult; D001812:Blood-Brain Barrier / Q000000981:diagnostic imaging* / Q000503:physiopathology; D016022:Case-Control Studies; D002540:Cerebral Cortex / Q000098:blood supply; D004833:Epilepsy, Temporal Lobe / Q000000981:diagnostic imaging* / Q000473:pathology* / Q000601:surgery; D019276:Glycocalyx / Q000473:pathology* / Q000502:physiology; D006624:Hippocampus / Q000098:blood supply; D006801:Humans; D007430:Intraoperative Care; D018715:Microscopy, Video / Q000379:methods; D055806:Microvessels / Q000000981:diagnostic imaging* / Q000503:physiopathology; D008875:Middle Aged; D009060:Mouth Floor / Q000098:blood supply; D009929:Organ Size; D011446:Prospective Studies; D012107:Research Design; D055815:Young Adult
keywords: Blood-brain barrier; Glycocalyx; Sidestream darkfield imaging; Temporal lobe epilepsy; observational study