title: Endothelial glycocalyx structure in the intact carotid artery: a two-photon laser scanning microscopy study.
abstract: BACKGROUND
  The endothelial glycocalyx (EG) is the carbohydrate-rich luminal lining of endothelial cells that mediates permeability and blood cell-vessel wall interactions. To establish an atheroprotective role of the EG, adequate imaging and quantification of its properties in intact, viable, atherogenesis-prone arteries is needed.
  
  
  METHODS
  Carotid arteries of C57Bl6/J mice (n=22) were isolated including the bifurcation, mounted in a perfusion chamber, and perfused with fluorescent lectin wheat germ agglutinin-fluorescein isothiocyanate. The EG was visualized through the vessel wall using two-photon laser scanning microscopy. An image quantification protocol was developed to assess EG thickness, which was sensitive to hyaluronidase-induced changes.
  
  
  RESULTS
  In the lesion-protected common carotid artery, EG thickness was found to be 2.3 ± 0.1 μm (mean ± SEM), while the surface area devoid of (wheat germ agglutinin-sensitive) EG was 8.9 ± 4.2%. Data from the external carotid artery were similar (2.5 ± 0.1 μm; 9.1 ± 5.0%). In the atherogenesis-prone internal carotid artery the EG-devoid surface area was significantly higher (27.4 ± 5.5%, p<0.05); thickness at the remaining areas was 2.5 ± 0.1 μm.
  
  
  CONCLUSIONS
  The EG can be adequately imaged and quantified using two-photon laser scanning microscopy in intact, viable mounted carotid arteries. Spatial EG differences could underlie atherogenesis.
authors.affiliation: Department of Biomedical Engineering, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, The Netherlands. s.reitsma@maastrichtuniversity.nl
authors.forename: Sietze
authors.initials: S
authors.lastname: Reitsma
authors.forename: Mirjam G A
authors.initials: MG
authors.lastname: oude Egbrink
authors.forename: Hans
authors.initials: H
authors.lastname: Vink
authors.forename: Bernard M
authors.initials: BM
authors.lastname: van den Berg
authors.forename: Valéria Lima
authors.initials: VL
authors.lastname: Passos
authors.forename: Wim
authors.initials: W
authors.lastname: Engels
authors.forename: Dick W
authors.initials: DW
authors.lastname: Slaaf
authors.forename: Marc A M J
authors.initials: MA
authors.lastname: van Zandvoort
mesh_terms: D000818:Animals; D050197:Atherosclerosis / Q000209:etiology; D002339:Carotid Arteries / Q000166:cytology*; D042783:Endothelial Cells / Q000648:ultrastructure*; D019276:Glycocalyx / Q000502:physiology / Q000648:ultrastructure*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018613:Microscopy, Confocal; D014909:Wheat Germ Agglutinins
chemical_list: D014909:Wheat Germ Agglutinins