HEAT-SHOCK PROTEIN (HSP-72) EXPRESSION IN PATIENTS UNDERGOING CARDIACOPERATIONS

The major mammalian stress-inducible protein, heat shock protein 72, p rotects cells from certain stresses and rapidly accumulates in cells a fter ischemia. Heat shock protein 72 is rapidly synthesized in the myo cardium of various species in response to ischemia, but it has not bee n investigated in human heart. To determine if heat shock protein 72 a ccumulated in the ischemic myocardium of patients undergoing cardiac o perations, we obtained sequential right atrial biopsy specimens from 1 2 patients undergoing repair at three intervals: before bypass, after reperfusion, and after bypass. Immunoblot analysis for heat shock prot ein 72 demonstrated a high expression in the human heart compared with other mammalian hearts, p(Binomial) = 0.01. Compared with before bypa ss, heat shock protein 72 contents after reperfusion and after bypass were 98.2% +/- 8.9%, p(signed-rank) = 0.65, and 87.6% +/- 17.1%, p(sig ned-rank) = 0.28, respectively. Although heat shock protein 72 concent ration was unchanged in hearts after reperfusion and after bypass, the initial prebypass level of heat shock protein 72 was high. The high h eat shock protein 72 level detected in human hearts may reflect preope rative disease and drug therapy, or inherently high levels may be usua l in the human myocardium. These findings indicate that the myocardium of patients undergoing cardiac operations contains relatively high co ncentrations of heat shock protein 72, which are not increased during the surgical procedure.