Urokinase in experimental vitreous hemorrhage

Area of Science:

• Ophthalmology
• Toxicology
• Pharmacology

Background:

• Intravitreal administration of therapeutic agents requires careful evaluation of ocular safety and efficacy.
• Urokinase, a thrombolytic enzyme, has been considered for treating vitreous hemorrhage.

Purpose of the Study:

• To assess the ocular toxicity of intravitreal urokinase in a primate model.
• To determine the efficacy of intravitreal urokinase in clearing experimentally induced vitreous hemorrhage.

Main Methods:

• Various doses of urokinase were injected into the vitreous cavity of primate eyes.
• Ocular tissues were examined for toxicity, and the ability of urokinase to resolve induced vitreous hemorrhage was evaluated at different time points.

Main Results:

• Doses of urokinase at 22,500 CTA units or less did not produce toxic effects.
• Higher doses resulted in retinal degeneration, temporary lens opacities, and vitreous cloudiness.
• Urokinase demonstrated ineffectiveness in clearing experimentally induced vitreous hemorrhage, regardless of administration timing (24 hours to 6 months post-induction).

Conclusions:

• Intravitreal urokinase is safe at doses up to 22,500 CTA units.
• Higher doses pose a risk of significant ocular toxicity.
• Urokinase is not an effective treatment for vitreous hemorrhage in this model.