Submitted on December 2, 2004
Accepted on April 6, 2005
Microdialysis separately monitors myocardial interstitial myoglobin during ischemic and reperfusion periods
Hirotoshi Kitagawa1, Toji Yamazaki2*, Tsuyoshi Akiyama2, Masaru Sugimachi3, Kenji Sunagawa4, and Hidezo Mori2
1 Cardiac Physiology, National Cardiovascular Center, Suita, Osaka, Japan
2 Anesthesiology, Shiga University of Medical Science, Otsu, Shiga, Japan
3 Cardiovascular Dynamics, National Cardiovascular Center, Suita, Osaka, Japan
4 Cardiovascular Medicine, Kyushu University Graduate School of Medical Sciences, Fukuoka, Fukuoka, Japan
* To whom correspondence should be addressed. E-mail: yamazaki{at}ri.ncvc.go.jp.
Direct monitoring of myoglobin efflux during the ischemic and reperfusion periods has been limited because of inherent sample collection problems in the ischemic region. Recently, cardiac dialysis technique has offered a powerful method for monitoring myocardial interstitial levels of low molecular compounds in the cardiac ischemic region. In the present study, we extended the molecular target to high molecular compounds by microdialysis probes with a high molecular mass cut-off and monitored myocardial interstitial myoglobin levels. We implanted a dialysis probe in the left ventricular free wall in anesthetized rabbits. The main coronary artery was occluded for 60 or 120 min. We examined the effects of myocardial ischemia and reperfusion on myocardial interstitial myoglobin levels. The interstitial myoglobin increased within 15 min-ischemia and continued to increase during 120 min-ischemia, whereas the blood myoglobin increased at 45 min-ischemia. The increases in lactate and myoglobin appeared in the interstitial space during the same period. At 60 min-ischemia, reperfusion markedly accelerated interstitial myoglobin release. The interstitial myoglobin level at 0-15 min of reperfusion was 5-fold higher than that of the same period of coronary occlusion. The dialysis technique permits earlier detection of myoglobin release and separately monitors its release during ischemic and reperfusion periods. Myocardial interstitial myoglobin levels can serve as an index of myocardial injury evoked by ischemia or reperfusion.
