LA419, a Novel Nitric Oxide Donor, Prevents Cardiac Remodeling Via the Endothelial Nitric Oxide Synthase Pathway

T he discovery of NO as the endothelium-derived relaxing factor unleashed new horizons.NO is a ubiquitous radical exerting both hemodynamic and tissue growth-modifying effects.The vasodilative and antiproliferative properties of NO produced by endothelial NO synthase are considered to act beneficially within the cardiovascular system.However, under certain circumstances, the inducible NO synthase produces large quantities of NO that may be harmful.1 Most NO effects can be attributed to the activation of soluble guanylate cyclase and the subsequent cascade of events including enhanced cGMP concentration, activation of cGMP-dependent kinase-1, and reduced intracellular calcium levels in target cells.NO acts as a principal regulator of vascular function.Venodilatation and arterial relaxation result in a decrease of left ventricular pressure and chamber size, leading to attenuation of oxygen consumption.NO dilates epicardial coronary arteries, enhances collateral flow, and inhibits platelet aggregation.Moreover, NO was shown to inhibit collagen synthesis and to reduce cardiomyocyte growth.NO, thus, represents an opposing force to vasoconstrictors and growth-promoting substances, such as angiotensin II and endothelin.The depression of NO signaling, including downregulated expression and attenuated enzymatic activity of NO synthase and scavenging of NO by oxygen-derived free radicals, seems to be a principal disorder in endothelial dysfunction.NO deficiency is, therefore, related to many cardiovascular pathologies, such as coronary atherosclerosis with myocardial ischemia, arterial hypertension with left ventricular hypertrophy, or heart failure.It is obvious that NO plays an important role in the circulatory physiology.Nevertheless, the impact of therapeutically increased NO bioactivity on cardiovascular morbidity and mortality is unclear.In the Gruppo Italiano per lo Studio della Streptochinasi nell'Inffarto Miocardico 3 and International Study of The opinions expressed in this editorial are not necessarily those of the editors or of the American Heart Association.