Sodium-calcium exchange inhibitors: therapeutic potential in cardiovascular diseases.

Intracellular calcium ions (Ca2+) are the key regulators in cardiac and arterial functions during the contraction-relaxation cycle. Myocyte Ca2+ imbalance thus produces mechanical dysfunction, electrical instability (arrhythmia) and muscle remodeling. The sodium-calcium exchanger (NCX) is one of the major Ca(2+)-handling proteins in myocytes. Evidence is currently accumulating to suggest that NCX1 is upregulated in various cardiovascular diseases. Recently developed benzyloxyphenyl NCX inhibitors effectively prevent myocardial ischemia/reperfusion injury and salt-sensitive hypertension in animal models. Furthermore, several experiments with genetically engineered mice provide compelling evidence that these diseases are triggered by pathologic Ca2+ entry through NCX1 in cardiac and arterial myocytes, respectively. Thus, NCX inhibitors may have therapeutic potential as novel cardiovascular drugs for myocardial reperfusion injury and salt-sensitive hypertension. However, the efficacy of NCX inhibitors, as well as the role of NCX1, in heart failure or arrhythmias requires more detailed study.