The Keio journal of medicine
-
A major mechanism by which the heart adapts to intracellular acidosis during ischemia and recovers from the acidosis after reperfusion is through the sodium-hydrogen exchanger (NHE). There are at least 5 NHE isoforms thus-far identified with the NHE-1 subtype representing the major one found in the mammalian myocardium. This 110 kDa glycoprotein extrudes protons concomitantly with Na influx in a 1:1 stoichiometric relationship rendering the process electroneutral. ⋯ In this regard, we have demonstrated that NHE inhibitors can effectively attenuate the cardiac injury produced by lysophosphatidylcholine and hydrogen peroxide. In addition, it now appears that NHE inhibition reduces apoptosis in the ischemic myocardium, a process which may be of importance in the subsequent development of postinfarction heart failure. In conclusion, NHE represents an important adaptive process in response to intracellular acidosis resulting in a paradoxical contribution to cardiac tissue injury.