Enhanced activity and subcellular redistribution of myocardial hexokinase after acute myocardial infarction.
BACKGROUND
Hexokinase (HK) is known to possess both anti-oxidant and anti-apoptotic properties. This study investigated the behavior of myocardial HK in response to myocardial infarction (MI).


METHODS
Adult male Wistar rats with various degrees of MI after coronary ligation were examined 4 weeks after operation and were divided dichotomously into small and large MI groups. The activity and subcellular distribution of HK in the non-infarcted myocardium were determined. In parallel, myocardial oxidative stress determined using aconitase activity and malondialdehyde content, and left ventricular function using echocardiography were studied.


RESULTS
In the mitochondria and the cytosol, HK activity was enhanced after MI and paralleled the increases in oxidative stress and left ventricular end-diastolic dimension (LVEDD). The enhancement in HK activity varied between subcellular compartments and resulted in an increase in the ratio of cytosol to whole-cell HK activity, which was proportional to oxidative stress and LVEDD.


CONCLUSIONS
The activities of HK in all subcellular fractions are enhanced in response to MI. However, enhanced proportion of cytosolic HK relative to whole-cell HK activity is associated with higher oxidative stress and LVEDD, suggesting that altered myocardial HK activity and subcellular redistribution might be involved in the pathogenesis of postinfarct heart failure.
Yeih
Dong-Feng
DF
Department of Cardiology, Far Eastern Memorial Hospital, Pan-Chiao, Taipei County, Taiwan.
Yeh
Hung-I
HI
Lin
Lian-Yu
LY
Tsay
Yeou-Guang
YG
Chiang
Fu-Tien
FT
Tseng
Chuen-Den
CD
Tseng
Yung-Zu
YZ
D000818:Animals; D003600:Cytosol / Q000201:enzymology; D004195:Disease Models, Animal; D004452:Echocardiography; D004734:Energy Metabolism / Q000502:physiology; D004789:Enzyme Activation / Q000502:physiology; D005954:Glucosephosphate Dehydrogenase / Q000235:genetics / Q000378:metabolism; D006593:Hexokinase / Q000378:metabolism*; D008297:Male; D008928:Mitochondria / Q000201:enzymology; D009203:Myocardial Infarction / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000473:pathology; D009206:Myocardium / Q000201:enzymology* / Q000473:pathology; D009929:Organ Size; D018384:Oxidative Stress / Q000502:physiology*; D010427:Pentose Phosphate Pathway / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar
D005954:Glucosephosphate Dehydrogenase; D006593:Hexokinase