Temporal Changes in Phosphatidylserine Expression and Glucose Metabolism after Myocardial Infarction: An In Vivo Imaging Study in Mice.

Positron emission tomography (PET) for in vivo monitoring of phosphatidylserine externalization and glucose metabolism can potentially provide early predictors of outcome of cardioprotective therapies after myocardial infarction. We performed serial [⁶⁸Ga]annexin A5 PET (annexin-PET) and [¹⁸F]fluorodeoxyglucose PET (FDG-PET) after myocardial infarction to determine the time of peak phosphatidylserine externalization in relation to impaired glucose metabolism in infracted tissue. Annexin- and FDG-PET recordings were obtained in female (C57BL6/N) mice on days 1 to 4 after ligation of the left anterior descending (LAD) artery. [⁶⁸Ga]annexin A5 uptake (%ID/g) in the LAD artery territory increased from 1.7 ± 1.1 on day 1 to 5.0 ± 3.3 on day 2 and then declined to 2.0 ± 1.4 on day 3 (p < .047 vs day 2) and 1.6 ± 1.4 on day 4 (p < .014 vs day 2). These results matched apoptosis rates as estimated by autoradiography and fluorescein staining. FDG uptake (%ID/g) declined from 28 ± 14 on day 1 to 14 ± 3.5 on day 4 (p < .0001 vs day 1). Whereas FDG-PET revealed continuous loss of cell viability after permanent LAD artery occlusion, annexin-PET indicated peak phosphatidylserine expression at day 2, which might be the optimal time point for therapy monitoring. [ABSTRACT FROM AUTHOR]

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