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Fluorescein transport across the human blood‐retina barrier in the direction vitreous to blood
Author(s) -
Engler Claus B.,
Sander Birgit,
Larsen Michael,
Dalgaard Peter,
LundAndersen Henrik
Publication year - 1994
Publication title -
acta ophthalmologica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.534
H-Index - 87
eISSN - 1755-3768
pISSN - 1755-375X
DOI - 10.1111/j.1755-3768.1994.tb04675.x
Subject(s) - fluorescein , retina , ophthalmology , blood–retinal barrier , medicine , optics , physics , fluorescence , diabetic retinopathy , endocrinology , diabetes mellitus
. Inward and outward movement of fluorescein across the human blood‐retina barrier was studied in five healthy volunteers, using a differential spectrofluorometry method that eliminates the contribution of fluorescein glucuronide to the total fluorescence in the vitreous and in plasma. The inward permeability across the blood‐retina barrier, which is presumed to be passive, and the diffusion coefficient in the vitreous for fluorescein was calculated from data obtained 1 h after intravenous injection of fluorescein. The rate of elimination of fluorescein from the vitreous across the blood‐retina barrier was estimated from data obtained 7 to 12 h after injection of fluorescein. The calculations were based upon the free plasma fluorescein decay curve and the preretinal fluorescein gradient in the vitreous. The mean inward permeability of fluorescein was 1.39 times 10 −7 cm/sec (range: 0.70‐2.06 times 10 −7 cm/sec), whereas the mean outward permeability was 1.51 times 10 −5 cm/sec (range: 1.14‐1.73 times 10 −5 cm/sec). We have thus found that the movement of fluorescein across the blood‐retina barrier is highly asymmetric, the outward transport being more than 100 times faster than the passive inward leakage. This could indicate the presence of an active pumping mechanism in the blood‐retina barrier, responsible for fluorescein transport in the direction from the vitreous to the blood.