Localization of the permeability barrier to solutes in isolated arteries by confocal microscopy

Paul M. A. van Haaren, Ed VanBavel, Hans Vink, Jos A. E. Spaan
2003 American Journal of Physiology. Heart and Circulatory Physiology  
Localization of the permeability barrier to solutes in isolated arteries by confocal microscopy. Am Endothelial cells are covered by a surface layer of membraneassociated proteoglycans, glycosaminoglycans, glycoproteins, glycolipids, and associated plasma proteins. This layer may limit transendothelial solute transport. We determined dimension and transport properties of this endothelial surface layer (ESL) in isolated arteries. Rat mesenteric small arteries (diameter ϳ150 m) were isolated and
more » ... annulated with a double-barreled -pipette on the inlet side and a regular pipette on the outlet side. Dynamics and localization of intraarterial fluorescence by FITC-labeled dextrans (FITC-⌬s) and the endothelial membrane dye DiI were determined with confocal microscopy. Large FITC-⌬ (148 kDa) filled a core volume inside the arteries within 1 min but was excluded from a 2.6 Ϯ 0.5-m-wide region on the luminal side of the endothelium during 30 min of dye perfusion. Medium FITC-⌬ (50.7 kDa) slowly penetrated this ESL within 30 min but did not permeate into the arterial wall. Small FITC-⌬ (4.4 kDa) quickly passed the ESL and accumulated in the arterial wall. Prolonged luminal fluorochrome illumination with a bright mercury lamp destroyed the ϳ3-m exclusion zone for FITC-⌬148 within a few minutes. This study demonstrates the presence of a thick ESL that contributes to the permeability barrier to solutes. The layer is sensitive to phototoxic stress, and its damage could form an early event in atherosclerosis. vascular permeability; isolated artery; endothelial surface layer; confocal microscopy; glycocalyx
doi:10.1152/ajpheart.00117.2003 pmid:12907418 fatcat:7cqpe64nsvh7xcmoz3dbkuwpie