Age dependence of plasma endothelin levels in glaucoma patients

The aim of the study was to investigate the endothelin-1 (ET-1) plasma level and its age dependence in patients with normal tension glaucoma (NTG), high tension glaucoma (HTG), and healthy controls. In blood samples from 35 NTG patients, 34 HTG patients, and 36 controls, ET-1 plasma levels were determined by enzyme-linked immunosorbent assay (ELISA). After adjustment for age and gender, the mean ET-1 levels were found to be similar in all three study groups. The age dependency however was highest in NTGs and significantly different from that of the controls. For the HTGs, this dependence was weaker and not significantly different from that of the controls. Our findings suggest that age had a significantly greater influence on ET plasma level in the NTG patients than in the HTG patients and controls. This supports previous reports indicating that ET plays a role in the pathogenesis of glaucoma, and in particular normal NTG.