Mitochondrial and myocardial performance. Response to ischemia and reperfusion
E. S. Weinstein, M. L. Spector, E. M. Adams, M. D. Yokum, R. W. Humphrey and D. E. Fry
The relationships between cardiac bioenergy metabolism and myocardial
function were examined in a model of global myocardial ischemia and
reperfusion. The respiratory activity of distinct populations of
subsarcolemmal and interfibrillar mitochondria was correlated with max
dP/dt (an index of myocardial contractility with respect to time). Max
dP/dt was significantly reduced to 27% of the preischemic value following
two hours of cardioplegia-protected, warm, global, ischemia in dogs during
the cardiopulmonary bypass period. Reperfusion resulted in improved
myocardial function such that by 60 minutes of reperfusion, max dP/dt
returned to baseline. Significant declines in both state 3 respiratory
rates and respiratory control indexes for subsarcolemmal and interfibrillar
mitochondria were noted following the ischemic interval. Mitochondrial
function similarly returned to baseline values following 60 minutes of
reperfusion. These data demonstrate a close association between
mitochondrial and myocardial activity.
