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Effect of camonagrel, a selective thromboxane synthase inhibitor, on retinal vascularization in experimental diabetes
J P De La Cruz1, A Moreno, M I Ruiz-Ruiz
1Department of Pharmacology and Therapeutics, School of Medicine, University of Málaga, Spain.
Insights
Thromboxane synthase inhibitors, camonagrel and dazoxiben, improved retinal vascularization in diabetic rats by increasing prostacyclin synthesis. Camonagrel showed significant potential for preventing ischemic diabetic retinopathy.
Area of Science:
- Biomedical research
- Pharmacology
- Ophthalmology
Background:
- Platelet hyperactivity, increased thromboxane, and decreased prostacyclin contribute to ischemic diabetic retinopathy.
- Understanding these factors is crucial for developing effective treatments.
Purpose of the Study:
- To investigate the effects of thromboxane synthase inhibitors (camonagrel and dazoxiben) on retinal vascularization in a rat model of diabetes.
- To assess the impact of these inhibitors on platelet aggregation, thromboxane, and prostacyclin synthesis.
Main Methods:
- Streptozotocin-induced diabetes model in rats.
- Treatment with varying doses of camonagrel or dazoxiben for 90 days.
- Measurement of platelet aggregation, thromboxane and prostacyclin synthesis, and retinal vascularity.
Main Results:
- Both drugs dose-dependently reduced platelet aggregation and thromboxane synthesis.
- Camongrel and dazoxiben significantly increased prostacyclin synthesis (154% and 78%, respectively).
- Retinal vascularity increased substantially with camonagrel (183%) and dazoxiben (74%), correlating with prostacyclin levels.
Conclusions:
- Increased prostacyclin synthesis appears more influential than thromboxane inhibition in preventing ischemic diabetic retinopathy.
- Camongrel demonstrates potential as an alternative therapeutic agent for preventing diabetic retinopathy lesions.
Abstract:
Platelet hyperactivity accompanied by an increased synthesis of thromboxane and/or a decreased prostacyclin production are important factors in ischemic diabetic retinopathy. We studied the effect of camonagrel and dazoxiben, two thromboxane synthase inhibitors, on retinal vascularization in a model of streptozotocin-induced diabetes in rats. Ten nondiabetic rats, 10 diabetic animals treated with saline (i.e., not treated), and 60 diabetic animals treated with dazoxiben or camonagrel (10, 50 or 100 mg kg(-1) day(-1) p.o.) were studied. All treatments lasted for 90 days. Dazoxiben and camonagrel produced a dose-dependent reduction in platelet aggregation and thromboxane synthesis. Dazoxiben increased prostacylin synthesis by 78% at 100 mg kg(-1) day(-1), and camonagrel by 154%. Dazoxiben increased retinal vascularity by 74%, and by 183% after camonagrel treatment. Prostacyclin synthesis showed a direct linear correlation with the degree of retinal vascularization (r2=0.6733, P < 0.00001). We conclude that an increased prostacyclin synthesis may have a greater influence than the inhibition of thromboxane synthesis in preventing ischemic diabetic retinopathy in experimental diabetes. Camonagrel may be an alternative treatment in the prevention of these lesions.