RESUMO
PURPOSE: To evaluate the activity of Renin-Angiotensin (SRA) and Kinin-Kalikrein (SKK) systems in patients with primary open-angle glaucoma (POAG) in tears, blood and aqueous flow. METHODS: Components of SRA and SKK were analysed in the blood, tears and aqueous flow of 38 patients found in different stages of POAG. The samples of aqueous flow were harvested during glaucoma surgery The results were compared to those from a healthy group of patients (for tears and blood) and to a group of normal patiens that had ocular surgery for cataract and high ametropias (for samples af aqueous flow). RESULTS: In patients with high pressure primary open-angle glaucoma, when comparing them to those from the control group, the measurements showed: a high level of angiotensin converting enzyme (ACE) activity (in tears up to 108-125%, p < 0.001 and in aqueous flow up to 40-47% p < 0.001), a high level of kalikrein (in tears up to 21-29%, p < 0.001 and in aqueous flow up to 35-44% p < 0.001) and a high level of the summed activity of prekalikrein +kalikrein (up to 11-14, p < 0.001). A decrease in the prekalikrein/kalikrein ratio was found (up to 21-25% p < 0.01 in tears and aqueous flow) and this decrease was proved to be in direct correlation to the glaucoma stages of evolution. A decrease in prekalikrein activity was also found; up to 7% in the tears for each developing glaucoma stage. After the glaucoma surgery, the levels of ACE activity and kalikrein measured in tears decreased (up to 17% p < 0.001 and 17% p < 0.001 respectively) without reaching the levels in the normal group while the levels of prekalikrein and the prekalikrein/kalikrein ratio grew (up to 7% p < 0.01 and 16% < 0.001 respectively). CONCLUSIONS: The results show a high level of kalikrein and angiotensin converting enzyme (ACE) activity (measured in aqueous flow and tears) when comparing the group with POAG to the normal group. A decrease in prekalikrein activity was found, and the prekalikrein/kalikrein ratio was also low in the aqueous flow and tears. After the glaucoma surgery the levels of ACE activity and kalikrein decreased without reaching the levels in the normal group while the levels of prekalikrein and the prekalikrei/kalikrein ratio grew.
