Gene transfer to the human trabecular meshwork by anterior segment perfusion

Abstract

Purpose: To determine whether adenovirus vectors are capable of transferring a foreign active protein to the perfused anterior segment of the human eye.

Methods: Primary cultures from the human trabecular meshwork tissue were exposed to replication-deficient adenovirus Av1LacZ4 carrying the reporter beta-galactosidase gene driven by the Rous Sarcoma Virus promoter. Anterior segments of six pairs of human eyes from normal donors were placed in organ culture and were perfused with culture medium at 2.5 microl/min constant flow. After 24 hours, one eye was injected once with 8 X 10(8) plaque-forming units (20 microl) of the viral vector, while the paired eye was injected with vehicle. Forty-eight hours (four pairs) and 7 days (two pairs) after injection, tissues were fixed, were assayed histochemically for transferred enzyme activity, and were analyzed morphologically.

Results: In monolayers, gene transfer occurs very efficiently in all distinct types of human outflow pathway cells. All human anterior segments injected with the adenovirus vector showed active gene transfer in cells of the outflow pathway: trabecular, juxtacanalicular, and inner wall of Schlemm's canal. Expression of the reporter enzyme was still present at 7 days after treatment. No activity was observed in any of the paired, vehicle-injected controls. Cell morphology and tissue architecture appeared normal in treated and control tissues, although some trabecular cell loss was observed in the corneoscleral and uveal regions of the perfused treated eyes.

Conclusions: Adenoviral vectors were able to transfer active foreign genes into perfused, intact human trabecular meshwork.