Silent Partner in Blood Vessel Homeostasis? Pervasive Role of Nitric Oxide in Vascular Disease

The endothelium is a rich source of biological mediators that serve to control blood flow, temper inflammation and maintain local homeostasis. Endothelium-derived nitric oxide (NO) is the prototype of these molecules and is critical in preventing the initiation and progression of vascular disease. Consistent with a central role for NO in vascular disease, disruptions in its production and/or bioavailability have been linked to hypertension, diabetes, hypercholesterolemia, obesity, aging, and smoking. Furthermore substrate and cofactor bioavailability, NOS isoform expression profiles and oxidative stress are crucial determinants as to whether homeostatic levels of NO are maintained in blood vessels. In addition to its direct actions, NO is an important modulator of other vasoregulatory pathways such as cyclooxygenase (COX)-derived eicosanoid production and angiotensin II generation by the renin-angiotensin system. Furthermore, NO may direct the selectivity of COX-2 inhibitors; a finding relevant to controversies associated with the use of these drugs. Herein, we examine pathways that are directly or indirectly modified by alterations in NO synthesis and that are targetable for the development of novel, effective and safe agents for the treatment of cardiovascular disease.