AJP - Endocrinology and Metabolism, Vol 263, Issue 6 E1046-E1053, Copyright © 1992 by American Physiological Society
Effects of high levels of fatty acids on functional recovery of ischemic hearts from diabetic rats
G. D. Lopaschuk, M. Saddik, R. Barr, L. Huang, C. C. Barker and R. A. Muzyka
Department of Pediatrics, University of Alberta, Edmonton, Canada.
In this study we determined the effects of high levels of fatty acids on
recovery of heart function when present either during or after ischemia.
Isolated working hearts from 6-wk streptozotocin diabetic and control rats
perfused with 11 mM glucose were subjected to 25 min of global ischemia
followed by 30 min of aerobic reperfusion. Four groups were studied: 1) 1.2
mM palmitate present before, during, and after ischemia; 2) 1.2 mM
palmitate present before and during ischemia, followed by reperfusion in
the absence of palmitate; 3) no palmitate before and during ischemia,
followed by 1.2 mM palmitate during reperfusion; and 4) no palmitate before
and during ischemia or during reperfusion. In control hearts, palmitate
during reperfusion depressed recovery of function regardless of whether
palmitate was present or absent during ischemia. In contrast, palmitate
present during reperfusion did not depress recovery of mechanical function
in the diabetic rat hearts. However, the presence of palmitate during
ischemia itself in diabetic rat hearts was detrimental to recovery of
mechanical function. The presence of palmitate during ischemia resulted in
an accelerated rate of ATP loss and a decreased rate of lactate
accumulation during ischemia, although this effect was similar in control
and diabetic rat hearts. Our results demonstrate that high concentrations
of fatty acids depress functional recovery of control rat hearts during the
reperfusion period but depress recovery of function in diabetic rat hearts
when present during ischemia itself.
