EDN1 and endothelial dysfunction: Specifically, microvascular endothelial dysfunction and abnormal vasoreactivity in response to the sympathetic autonomic nervous system (PVD, primary vascular dysregulation, according to Flammer and colleagues) have been observed, supported by an imbalance between nitric oxide (NO, vasodilator) and endothelin-1 (ET-1, vasoconstrictor) [60].