NOS3 and congenital bilateral aplasia of vas deferens from CFTR mutation: Indeed, alongside eNOS uncoupling, several other mechanisms are responsible for reducing NO synthesis in CAVD including mechanical stress-induced down-regulation of eNOS expression,210,211 and valvular endothelial-mesenchymal transition which occurs as a result of TGF-β1 stimulation,212 the constituent elements of the ECM,213 shear and mechanical stress,214 and protein S-glutathionylation—the consequence of an imbalance between reduced and oxidized glutathione.215