EDN1 and Hypertension: In in vitro experiments on vascular endothelial cells, methylation of the CpG island in the ECE-1c promoter region decreases its transcriptional activity, resulting in decreased expression of ECE-1c, further leading to decreased production of ET-1 and decreased blood pressure in vivo, and this line of changes suggests that ECE-1 methylation may be involved in the pathology of hypertension [40, 41].