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Introduction: Glaucoma isone of the major causes of blindness in western countries. Several lines of evidence indicate that a local increase of the strong vasoconstrictor endothelin may contribute to the development of glaucoma by inducing neurotoxicity and reducing ocular blood flow. Thus, the current study seeks to test the hypothesis that administration of bosentan, an unspecific endothelin receptor antagonist increases ocular blood flow. Methods: Fourteen patients with primary open angle glaucoma and 14 age and sex matched healthy subjects were included in the study. Both experimental groups received 500 mg bosentan daily for 8 days. Ocular hemodynamics was assessed at baseline and after administration of bosentan. For this purpose, retinal vessel diameters, red blood cell velocity and optic nerve head blood flow were measured with a Retinal Vessel Analyzer and laser Doppler technology, respectively. Results: Retinal vessel diameters, red blood cell velocity and calculated retinal blood flow increased after administration of bosentan in both groups (P < 0.05). Furthermore, 8 days administration of bosentan significantly increased optic nerve head blood flow. No difference was observed in the bosentan induced increase in blood flow between the glaucoma and the healthy group. Conclusion: Our data indicate that administration of the dual endothelin receptor antagonist bosentan increases ocular blood flow in patients with glaucoma and healthy subjects. Further studies are needed to investigate whether bosentan is an option to therapeutically increase blood flow in patients with ocular vascular disease.
G. Garhofer. Medical University of Vienna, Department of Clinical Pharmacology, ViennaAustria.
11.14 Investigational drugs; pharmacological experiments (Part of: 11 Medical treatment)
6.11 Bloodflow measurements (Part of: 6 Clinical examination methods)