Data on the involvement of endothelin-1 (ET-1) in the dysregulation of retinal veins

While the pathogenesis of retinal vein occlusion (RVO) is still unclear, systemic hypertension and increased level of endothelin-1 (ET-1) are known risk factors (Flammer and Konieczka, 2015) [2]. We focused on the behavior of retinal veins in spontaneous hypertensive rats (SHR). Then, one of the retinal veins became exceptionally constricted and was nearly occluded (Fig. 1), and the chorioretinal blood flow significantly decreased in the retinas of SHRs following the intravenous injection of ET-1. In addition, immunoreactivity to ET-A receptor was higher in SHR retinas than in control (WKY; Wistar Kyoto rat) retinas (Fig. 2). The protein levels of ET-A receptor and HIF-1 were also significantly higher in SHR retinas than in WKY retinas (Fig. 3). We observed vasoactivity of retinal veins; a retinal venous constriction (Kida et al., 2018) [3]. This supports the hypothesis that ET-1 can constrict retinal veins, thus increasing retinal venous pressure, and that ET-1 may even contribute to the pathogenesis of RVO.