Lack of cardioprotection from metabolic support with glutamine or glutamate in a porcine coronary occlusion model.
OBJECTIVE
Previous experimental studies indicate that glutamine or glutamate may provide cardioprotection by improving the oxidative metabolism in myocardial ischemia. We investigated the effect of glutamine or glutamate, given during reperfusion, on resulting infarct size and hemodynamic recovery.


METHODS
A porcine coronary occlusion model was applied. Infusions were initiated 15 min before reperfusion and supplemented with intracoronary bolus doses at reperfusion. The primary outcome measure was infarct size in relation to area at risk determined by a standard tissue staining procedure. Secondary outcome measures were the hemodynamic variables.


RESULTS
The infarct sizes as a proportion of the area at risk (mean+/-SD) were: control group, 0.64 +/- 0.19 (n = 9); glutamine group, 0.87 +/- 0.07 (p < 0.05 vs control group) (n = 8); glutamate group, 0.72 +/- 0.11 (n = 9). Glutamine increased systemic vascular resistance, while glutamate preserved cardiac output during infusion.


CONCLUSIONS
Substrate supplementation with the anaplerotic precursors glutamine and glutamate is ineffective as adjunctive therapy for severe myocardial ischemia. Beneficial effects documented in less complex experimental systems could not be transferred to a more pathophysiological relevant model.
Kristensen
Jens
J
Department of Nuclear Medicine, Aarhus University Hospital, Skejby Hospital, Aarhus, Denmark. jenskristensen@dadlnet.dk
Maeng
Michael
M
Mortensen
Ulrik Markus
UM
Berg
Jette
J
Rehling
Michael
M
Nielsen
Torsten Toftegaard
TT
D000704:Analysis of Variance; D000818:Animals; D003326:Coronary Circulation / Q000502:physiology; D003327:Coronary Disease / Q000000981:diagnostic imaging / Q000188:drug therapy* / Q000473:pathology; D004195:Disease Models, Animal; D005260:Female; D018698:Glutamic Acid / Q000494:pharmacology*; D005973:Glutamine / Q000494:pharmacology*; D006439:Hemodynamics / Q000502:physiology; D007262:Infusions, Intravenous; D019157:Ischemic Preconditioning, Myocardial / Q000379:methods*; D008297:Male; D015428:Myocardial Reperfusion Injury / Q000517:prevention & control*; D011336:Probability; D011897:Random Allocation; D012016:Reference Values; D012307:Risk Factors; D012680:Sensitivity and Specificity; D013552:Swine; D015899:Tomography, Emission-Computed, Single-Photon; D014654:Vascular Patency
D005973:Glutamine; D018698:Glutamic Acid