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Urokinase-type plasminogen activator in human aqueous humor
S F Bernatchez1, C Tabatabay, D Belin
1Centre Hospitalier de l'Université Laval, Québec, Canada.
Investigative Ophthalmology & Visual Science
|August 1, 1992
Summary
Aqueous humor contains active urokinase-type plasminogen activator (uPA), promoting fibrinolysis to prevent eye scarring after cataract surgery. This suggests a natural mechanism for clot breakdown in the anterior eye segment.
Area of Science:
- Ophthalmology
- Biochemistry
- Molecular Biology
Background:
- Fibrin clot resorption is crucial in the anterior eye segment to prevent fibrosis and scarring.
- Understanding the fibrinolytic system in aqueous humor is vital for ocular health, especially post-surgery.
Purpose of the Study:
- To analyze the aqueous humor of cataract surgery patients for fibrinolytic cascade components.
- To compare the concentrations of key fibrinolytic factors in aqueous humor versus plasma.
Main Methods:
- Collected aqueous humor and plasma from 30 cataract surgery patients.
- Utilized gel electrophoresis and zymographic assays to quantify urokinase-type plasminogen activator (uPA), tissue-type plasminogen activator (tPA), plasminogen activator inhibitors (PAIs), plasminogen, and total proteins.
Main Results:
- All analyzed fibrinolytic components were present at lower concentrations in aqueous humor compared to plasma.
- A relatively high concentration of active, two-chain uPA was detected in aqueous humor.
- Lower levels of tPA and undetectable reactive PAI levels were observed in aqueous humor.
Conclusions:
- Aqueous humor possesses a proteolytic balance favoring fibrinolysis due to significant active uPA levels.
- This suggests an intrinsic mechanism for rapid fibrin clot breakdown in the anterior chamber of the eye.
- Findings contribute to understanding ocular wound healing and potential therapeutic targets.