Combined 19F/1H MRI in a rat model revealed that monocyte recruitment was significantly impaired in microvascular obstruction areas, leading to worse left ventricular pump function 28 days after MI.
Combined 19F/1H cardiac MRI can noninvasively monitor monocyte recruitment in reperfused MI, revealing that impaired infiltration in microvascular obstruction areas correlates with worse long-term ventricular function.
BACKGROUND: Monocytes and macrophages are indispensable in the healing process after myocardial infarction (MI); however, the spatiotemporal distribution of monocyte infiltration and its correlation to prognostic indicators of reperfused MI have not been well described. METHODS AND RESULTS: With combined fluorine 19/proton ((1)H) magnetic resonance imaging, we noninvasively visualized the spatiotemporal recruitment of monocytes in vivo in a rat model of reperfused MI. Blood monocytes were labeled by intravenous injection of (19)F-perfluorocarbon emulsion 1 day after MI. The distribution patterns of monocyte infiltration were correlated to the presence of microvascular obstruction (MVO) and intramyocardial hemorrhage. In vivo, (19)F/(1)H magnetic resonance imaging performed in series revealed that monocyte infiltration was spatially inhomogeneous in reperfused MI areas. In the absence of MVO, monocyte infiltration was more intense in MI regions with serious ischemia-reperfusion injuries, indicated by severe intramyocardial hemorrhage; however, monocyte recruitment was significantly impaired in MVO areas accompanied by severe intramyocardial hemorrhage. Compared with MI with isolated intramyocardial hemorrhage, MI with MVO resulted in significantly worse pump function of the left ventricle 28 days after MI. CONCLUSIONS: Monocyte recruitment was inhomogeneous in reperfused MI tissue. It was highly reduced in MVO areas defined by magnetic resonance imaging. The impaired monocyte infiltration in MVO regions could be related to delayed healing and worse functional outcomes in the long term. Therefore, monocyte recruitment in MI with MVO could be a potential diagnostic and therapeutic target that could be monitored noninvasively and longitudinally by (19)F/(1)H magnetic resonance imaging in vivo.
Ye et al. (Thu,) conducted a other in Reperfused myocardial infarction. Combined fluorine 19 and proton cardiac magnetic resonance imaging was evaluated on Spatiotemporal recruitment of monocytes and left ventricular pump function. Combined 19F/1H MRI in a rat model revealed that monocyte recruitment was significantly impaired in microvascular obstruction areas, leading to worse left ventricular pump function 28 days after MI.