title: Vascular expression of endothelial antigen PAL-E indicates absence of blood-ocular barriers in the normal eye.
abstract: The endothelium-specific antigen PAL-E is expressed in capillaries and veins throughout the body with the exception of the brain, where the antigen is absent from anatomical sites with a patent blood-brain barrier. In this study we determined vascular endothelial staining for PAL-E in the normal eye in relation to the ocular blood-tissue barriers. Immunohistochemical staining of frozen tissue sections of eyes from 22 cornea donors and a number of normal animal autopsy eyes was performed for the PAL-E antigen and the blood-brain barrier marker glucose transporter 1. In normal human and animal eyes, endothelial PAL-E staining was absent from the microvasculature in iris, ciliary muscle, optic nerve and retina. In a few normal human eyes, some weakly stained capillaries were observed in the retina and nerve fiber layer, mostly in the peripapillary area. Marked staining of capillaries and venules with PAL-E was observed in the conjunctiva, episclera, sclera, ciliary processes, choriocapillaris and optic nerve head. In general, the endothelial antigen PAL-E is absent from microvessels involved in the blood-ocular and the blood-retinal barriers. PAL-E may therefore be a useful marker to identify pathological breakdown of blood-ocular barriers.
authors.affiliation: Department of Ophthalmology, University of Amsterdam, The Netherlands.
authors.forename: R O
authors.initials: RO
authors.lastname: Schlingemann
authors.forename: P
authors.initials: P
authors.lastname: Hofman
authors.forename: L
authors.initials: L
authors.lastname: Anderson
authors.forename: D
authors.initials: D
authors.lastname: Troost
authors.forename: R
authors.initials: R
authors.lastname: van der Gaag
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal; D000954:Antigens, Surface / Q000276:immunology / Q000378:metabolism*; D001158:Arteries / Q000378:metabolism; D001693:Biological Transport, Active; D002417:Cattle; D004730:Endothelium, Vascular / Q000276:immunology / Q000378:metabolism*; D005123:Eye / Q000098:blood supply*; D051272:Glucose Transporter Type 1; D006801:Humans; D007124:Immunoenzyme Techniques; D008252:Macaca fascicularis; D009004:Monosaccharide Transport Proteins / Q000378:metabolism; D011817:Rabbits; D012756:Sheep; D013552:Swine; D014680:Veins / Q000378:metabolism
chemical_list: D000911:Antibodies, Monoclonal; D000954:Antigens, Surface; D051272:Glucose Transporter Type 1; D009004:Monosaccharide Transport Proteins; C495677:SLC2A1 protein, human