Bradykinin sensitivity in primary open-angle glaucoma and normal-tension glaucoma patients

PURPOSE: To report the reaction after intradermal injection of bradykinin in nonglaucoma, primary open-angle glaucoma, and normal-tension glaucoma subjects. DESIGN: Prospective comparative study. METHODS: The study participants were 14 healthy control subjects, 16 patients with primary open-angle glaucoma, and 15 patients with normal-tension glaucoma. In each participant, the wheal response to intradermal injection of 10 μg bradykinin in the volar forearm was measured by a masked observer. RESULTS: There was no significant difference in the wheal response to bradykinin between control subjects and primary open-angle glaucoma patients (P = .73) and between primary open-angle glaucoma patients and normal-tension glaucoma patients (P = .09). However, there was a significant difference in the wheal response to bradykinin between control subjects and normal-tension glaucoma patients (P = .04). CONCLUSIONS: These in vivo structure-activity studies may suggest abnormalities of the tissue kallikrein-kinin system in normal-tension glaucoma.