Cardiac glucose uptake and suppressed expression/translocation of myocardium glucose transport-4 in dogs undergoing ischemia-reperfusion.
Impaired glucose metabolism is implicated in cardiac failure during ischemia-reperfusion. This study examined cardiac glucose uptake and expression of glucose transport-4 (GLUT-4) in dogs undergoing ischemia-reperfusion. Cardiac ischemia was induced by cardiopulmonary bypass for 30 min or 120 min in dogs. Plasma insulin and glucose concentrations were measured at pre-bypass (control), and aortic cross-clamp off (ischemia-reperfusion) at 15, 45, and 75 min. At the same time, the left ventricle biopsies were taken for GLUT-4 immunohistochemistry and glycogen content analysis. In dogs receiving 120-min ischemia, coronary arterial and venous glucose concentrations were increased, but the net glucose uptake in ischemia-reperfusion heart were significantly decreased from 25% (control) to zero at 15 and 45 min of reperfusion, and recovered to only 7% after 75 min reperfusion. Myocardium glycogen contents were decreased by 65%. Plasma insulin levels and Insulin Resistant Index were markedly increased in dogs undergoing 120-min ischemia and reperfusion. These changes were relatively mild and reversible in dogs receiving only 30-min ischemia followed by reperfusion. Expression of total GLUT-4 in myocardium was decreased 40% and translocation of GLUT-4 from cytoplasm to surface membrane was decreased 90% in dogs receiving 120-min ischemia followed by 15-min reperfusion. Suppressed translocation of GLUT-4 was also evident in dogs receiving 30-min ischemia, but to a lesser extent. Reduced myocardium glucose uptake, utilization, and glycogen content are clearly associated with ischemia-reperfusion heart injury. This appears to be due, at least in part, to suppressed expression and translocation of myocardium GLUT-4.
Affiliated Hospital of Zunyi Medical College, Department of Thoracic and Cardiovascular Surgery, 149 Da-Lian Road, Zunyi, Guizhou 563003, China. guiyou515@163.com
Gui-You
GY
Liang
Qing-Yong
QY
Cai
Yi-Ming
YM
Niu
Hong
H
Zheng
Zhen-Yu
ZY
Gao
Da-Xing
DX
Liu
Gang
G
Xu
D000818:Animals; D001706:Biopsy; D004285:Dogs; D005947:Glucose / Q000378:metabolism*; D051275:Glucose Transporter Type 4 / Q000378:metabolism*; D007150:Immunohistochemistry; D007328:Insulin / Q000097:blood; D007333:Insulin Resistance; D015428:Myocardial Reperfusion Injury / Q000378:metabolism*; D021381:Protein Transport
D051275:Glucose Transporter Type 4; D007328:Insulin; D005947:Glucose