Retroperfusion studies of the aqueous outflow system. Part I: Evaluation of technique using N-ethyl maleimide.
OBJECTIVE
The goal of this study was to develop a new technique to deliver drugs or other agents to the lumen of the angular aqueous plexus/Schlemm's canal (AAP/SC) while bypassing the trabecular meshwork, thereby gaining insight into AAP/SC inner wall function.


METHODS
The anterior chamber is held at a small negative pressure and fluid is allowed to flow retrograde from the limbal vessels, through the collector channels, and into the AAP/SC ("retroperfusion"). Facility measurements are combined with histologic and tracer studies in bovine eyes.


RESULTS
(1) Retroperfusion with a saline solution does not alter facility or change outflow pathway morphology; (2) fluid is able to move retrograde from the scleral surface and enter the lumen of the AAP; and (3) retroperfusion with N-ethyl maleimide causes a dose-dependent increase in washout rate and concomitant inner wall breaks.


CONCLUSIONS
It is hypothesized that the observed increase in washout is due to leakage of extracellular materials through breaks in the inner wall.
Ethier
C R
CR
Institute for Biomedical Engineering, University of Toronto, Ontario, Canada.
Coloma
F M
FM
de Kater
A W
AW
Allingham
R R
RR
D000818:Animals; D000867:Anterior Chamber / Q000378:metabolism* / Q000648:ultrastructure; D001082:Aqueous Humor / Q000378:metabolism*; D002417:Cattle; D016503:Drug Delivery Systems; D005033:Ethylmaleimide / Q000008:administration & dosage / Q000494:pharmacology*; D005069:Evaluation Studies as Topic; D005293:Ferritins / Q000378:metabolism; D010477:Perfusion / Q000379:methods*; D012636:Secretory Rate / Q000187:drug effects; D014129:Trabecular Meshwork / Q000378:metabolism / Q000648:ultrastructure
D005293:Ferritins; D005033:Ethylmaleimide