Low levels of plasma endothelin-1 in patients with retinitis pigmentosa

Purpose: The aim of this study was to elucidate the role of endothelin-1 (ET-1) in the pathophysiology of retinitis pigmentosa (RP). Methods: Plasma ET-1 levels and ophthalmic features in 50 RP patients were compared with those in 20 healthy-eye control subjects. Plasma ET-1 concentrations were determined using a commercially available enzyme-linked immunosorbent assay kit. Results: Mean plasma ET-1 levels of RP patients (1.88 +/- 0.56 pg/mL) were significantly lower than those of control subjects (2.30 +/- 0.30 pg/mL, Mann-Whitney's U test; P < 0.01). However, ET-1 concentrations varied markedly in each patient. Among RP patients, a significant correlation of ET-1 concentrations was not observed in terms of its hereditary forms or other clinical factors. Conclusion: ET-1 may be important in the pathogenesis of RP, and measurement of its plasma concentrations may also contribute to additional insights into the retinal hemodynamics of RP.