Cardiac glucose uptake and suppressed expression/translocation of myocardium glucose transport-4 in dogs undergoing ischemia-reperfusion.

Abstract

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.

• Authors: Gui-You Liang, Qing-Yong Cai, Yi-Ming Niu, Hong Zheng, Zhen-Yu Gao, Da-Xing Liu, Gang Xu
• Journal: Experimental biology and medicine (Maywood, N.J.) (Exp Biol Med (Maywood)) Vol. 233 Issue 9 Pg. 1142-8 (Sep 2008) ISSN: 1535-3702 [Print] England
• PMID: 18535164 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Glucose Transporter Type 4
• Insulin
• Glucose

Topics

• Animals
• Biopsy
• Dogs
• Glucose (metabolism)
• Glucose Transporter Type 4 (metabolism)
• Immunohistochemistry
• Insulin (blood)
• Insulin Resistance
• Myocardial Reperfusion Injury (metabolism)
• Protein Transport