Intermittent warm blood cardioplegia induces the expression of heat shock protein-72 by ischemic myocardial preconditioning.
OBJECTIVE
Recent studies have demonstrated that the induction of heat shock protein-72 (HSP72) by different stimuli preserves the heart function after cardioplegic arrest. Based on these findings, we investigated whether intermittent warm blood cardioplegia would induce changes in the myocardial expression of HSP72.


METHODS
Forty patients scheduled for aortocoronary bypass were randomly assigned to receive either cold or warm intermittent blood cardioplegia. In all patients HSP72 and HSP72 mRNA were assayed in biopsies from the right atrium at baseline, and during the reperfusion period. Plasma CK-MB and troponin-T, and myocardial oxygen extraction and lactate release were also measured.


RESULTS
In both groups, myocardial expression of HSP72 increased throughout the reperfusion period, but the values of HSP72 band lengths were significantly higher in the warm group. Correspondingly, HSP72 mRNA levels increased progressively in both groups, with significant difference between groups observed in biopsies at the reperfusion. Warm blood cardioplegia was associated with lower levels of CK-MB and troponin-T. Myocardial oxygen extraction and lactate release were higher during intermittent warm cardioplegia, indicating a more profound ischemic anaerobic metabolism in the warm group.


CONCLUSIONS
Intermittent warm blood cardioplegia induces an increased expression of HSP72 and it is associated with a better myocardial protection, by a mechanism involving a variant of the classical ischemic preconditioning model.
Chello
M
M
Interdisciplinary Center for Biomedical Research (CIR), Department of Cardiovascular Sciences, University Campus Bio-Medico of Rome, Italy. m.chello@unicampus.it
Mastroroberto
P
P
Patti
G
G
D'Ambrosio
A
A
Di Sciascio
G
G
Covino
E
E
D001026:Coronary Artery Bypass; D003402:Creatine Kinase / Q000097:blood; D052279:Creatine Kinase, MB Form; D005260:Female; D015870:Gene Expression; D050884:HSP72 Heat-Shock Proteins; D006324:Heart Arrest, Induced / Q000379:methods*; D006360:Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D019157:Ischemic Preconditioning, Myocardial; D007527:Isoenzymes / Q000097:blood; D019344:Lactic Acid / Q000097:blood; D008297:Male; D008875:Middle Aged; D009206:Myocardium / Q000378:metabolism*; D010101:Oxygen Consumption; D012333:RNA, Messenger / Q000235:genetics; D013696:Temperature; D020107:Troponin T / Q000097:blood
D050884:HSP72 Heat-Shock Proteins; D006360:Heat-Shock Proteins; D007527:Isoenzymes; D012333:RNA, Messenger; D020107:Troponin T; D019344:Lactic Acid; D003402:Creatine Kinase; D052279:Creatine Kinase, MB Form