Relationship Between Plasma Levels Of Endothelin-1 And Ocular Hemodynamic Changes In Patients With Primary Open Angle Glaucoma

Objective: To investigate the relationship between plasma levels of endothelin-1 (ET-1) and ocular hemodynamic changes in patients with primary open angle glaucoma (POAG). Methods: The plasma concentration of endothelin-1 was determined by radioimmunoassay in 30 cases of POAG and 30 cases of normal subjects. The peak systolic velocity (PSV), end diastolic velocity (EDV) and resistive index (RI) of ophthalmic artery (OA), short posterior ciliary artery (SPCA) and central retinal artery (CRA) were measured simultaneously with color Doppler imaging (CDI). Results: The plasma levels of ET-1 was significantly higher in patients with POAG than in normal subjects(P < 0.01). The EDV of OA in POAG was lower than that in normal subjects(P < 0.01),and their RI was higher than that in normal subjects(P < 0.01), but there was no significant difference in the PSV of OA between two groups(P > 0.05). Compared with the normal subjects, the patients with POAG showed statistically significant lower PSV,EDV and higher RI in both SPCA and CRA(P < 0.01). The plasma levels of ET-1 in patients with POAG was significantly negatively correlated with the EDV of OA and SPCA(P < 0.01), and was significantly positively correlated with the RI of OA and SPCA(P < 0.01),and was significantly negatively correlated with the PSV of CRA and SPCA(P < 0.05), and wasn't significantly correlated with the PSV of OA,EDV and RI of CRA(P > 0.05). There was no significant correlations between ET-1 levels in plasma and the parameters of ocular hemodynamics in the normal subjects. Conclusions: (1) The increase of plasma levels of ET-1 in patients with POAG may be related to the pathogenesis of POAG. (2) Ocular hemodynamic changes of POAG result in deficiency of the blood supply to the optic nerve, and may lead to the damage of optic nerve. (3) ET-1 and the ocular hemodynamic changes lead to the microvascular dysfuction of optic nerve head and the optic nerve ischemia, and may play an important role in the pathogenesis of damage of optic nerve and visual field in POAG. (4) The ocular hemodynamic changes were correlated with ET-1 levels in plasma of patients with POAG.