Is glutamine beneficial in ischemic heart disease?

OBJECTIVE: Glutamine enhances recovery from acute normothermic ischemia in isolated rat heart by a dose-dependent effect (Khogali et al. J Mol Cell Cardiol 1998;30:819). We compared the cardioprotective effects of equimolar concentrations of glutamine, glutamate, and aspartate in isolated rat heart. We also explored the potential cardioprotective effects of glutamine in patients with chronic stable angina. METHODS: The isolated perfused working rat heart was subjected to ischemia, followed by reperfusion with or without an amino acid (2.5 mM). Patients with chronic stable angina received a single oral dose of glutamine (80 mg/kg) or placebo in a double-blind, random fashion 40 min before a standard Bruce exercise test. RESULTS: Postischemic reperfusion of isolated rat heart with glutamine (but not with glutamate or aspartate) resulted in full recovery of cardiac output. Only glutamine prevented the decrease in the myocardiol ratio between adenosine triphosphate to adenosine diphosphate and significantly enhanced the myocardial ratio of reduced to oxidized glutathione. A single oral dose of glutamine given to patients with chronic stable angina significantly increased plasma glutamine concentration from 419 to 649 μM and delayed time to onset of more than 1.0 mm of ST segment depression on the ECG by 38 s. CONCLUSION: Glutamine may be cardioprotective in patients with coronary heart disease.