Nitroxyl (HNO) for treatment of acute heart failure

The loss of contractile function is a hallmark of heart failure. Although increasing intracellular Ca2+ is a possible strategy for improving contraction, current inotropic agents that achieve this by raising intracellular cAMP levels, such as β-agonists and phosphodiesterase inhibitors, are generally deleterious when administered as long-term therapy due to arrhythmia and myocardial damage. Nitroxyl donors have been shown to improve cardiac function in normal and failing dogs, and in isolated cardiomyocytes they increase fractional shortening and Ca2+ transients, independently from cAMP/PKA or cGMP/PKG signaling. Instead, nitroxyl targets cysteines in the EC-coupling machinery and myofilament proteins, reversibly modifying them to enhance Ca2+ handling and myofilament Ca2+ sensitivity. Phase I-IIa trials with CXL-1020, a novel pure HNO donor, reported declines in left and right heart filling pressures and systemic vascular resistance, and increased cardiac output and stroke volume index. These findings support the concept of nitroxyl donors as attractive agents for the treatment of acute decompensated heart failure. © 2014 Springer Science+Business Media.