Macrophage mannose receptor CD206-targeted PET imaging in experimental acute myocardial infarction

Figures

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  Fig. 1. Animal study design. Sprague Dawley rats (n = 23) underwent permanent LAD ligation or sham-operation on Day 0. Then, the rats were divided to four groups: MI Day 3 (Group 1), Sham Day 3 (Group 2), MI Day 7 (Group 3), and Sham Day 7 (Group 4). All rats were imaged with [18F]FDG PET/CT 1 day before Al[18F]F-NOTA-D10CM PET/CT. All rats were euthanized immediately after Al[18F]F-NOTA-D10CM PET/CT imaging to measure ex vivo biodistribution, autoradiography, hematoxylin–eosin (H&E) staining, CD206 immunohistochemical staining, and double CD206 and CD68 immunofluorescence staining of the left ventricle

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  Fig. 2. Binding of Alexa-488-NOTA-D10CM to human M1 versus M2 macrophages. A Peripheral blood mononuclear cells were polarized into M1 and M2 macrophages in vitro. Representative flow cytometry histograms (upper panels) and quantification (lower panels) of CD206 expression. B Representative flow cytometry histograms (upper panels) and quantification of Alexa-488-NOTA-D10CM binding (lower panels) to M1 and M2 macrophages after a 30-min or 4-h incubation. MFI mean fluorescence intensity. P values are from Student’s t test

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  Fig. 3. Binding of Al[18F]F-NOTA-D10CM to CD206+ versus CD206− cells. A Representative flow cytometry histograms of mouse CD206 expression on naive Chinese hamster ovary cells (CHO-CD206−) and CD206-transfected cells (CHO-CD206+), as detected by an AlexaFluor-488 anti-mouse CD206 antibody. B Quantification of CD206 expression. MFI, mean fluorescence intensity. (C) An example of real-time binding of Al[18F]F-NOTA-D10CM to CHO-CD206+ and CHO-CD206− cells, as determined using the LigandTracer instrument. cps counts per second. P values are from Student’s t test

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  Fig. 4. In vivo PET imaging of rats with myocardial infarction (MI). A Representative Al[18F]F-NOTA-D10CM and [18F]FDG PET images of rats on Day 3 and Day 7 after MI. [18F]FDG visualizes viable myocardium (blue arrows), while Al[18F]F-NOTA-D10CM shows uptake in the infarcted and border zone areas (red arrows). The white arrows denote tracer uptake in the healing surgical scar. B Time-activity curves of the blood pool, MI area, and remote area on Day 3 and Day 7 after MI, and of the myocardium of sham-operated rats. C Quantification of in vivo Al[18F]F-NOTA-D10CM PET/CT reveals significantly higher tracer uptake in the MI area both on Day 3 and Day 7 after MI (compared with the remote area or the myocardium of sham-operated rats). SUV standardized uptake value. P values are from one-way ANOVA

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  Fig. 5. Autoradiography of myocardial Al[18F]F-NOTA-D10CM uptake and quantification of CD206-positive cells. A Representative Al[18F]F-NOTA-D10CM autoradiographs, hematoxylin–eosin (H&E) staining, and anti-CD206 immunohistochemical staining of the rat left ventricle on Day 3 and Day 7 after myocardial infarction (MI). Quantification of B Al[18F]F-NOTA-D10CM autoradiography and C CD206-positive staining reveals significantly higher signals in the infarcted and border zone areas on both Day 3 and Day 7 after MI. D Correlation between the Al[18F]F-NOTA-D10CM in vivo PET results for the infarct area and A the % CD206-positive stained area or E ex vivo autoradiography of Al[18F]F-NOTA-D10CM on Day 3 and Day 7 after myocardial infarction. PSL/mm2 photostimulated luminescence per square millimeter. P values are from one-way ANOVA and correlation coefficients from Pearson’s analysis

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  Fig. 6. CD206 and CD68 in rat myocardial tissue after infarction. Double immunofluorescence staining of a rat left ventricle reveals co-localization of CD68-positive staining and macrophage mannose receptor CD206-positive staining in the injured area on Day 7 after MI

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  Fig. 7. In vitro competitive study confirming Al[18F]F-NOTA-D10CM binding specificity. A Representative Al[18F]F-NOTA-D10CM autoradiographs, and hematoxylin–eosin (H&E) and anti-CD206 staining of adjacent cryosections of the left ventricle post-myocardial infarction (MI). B Quantification of Al[18F]F-NOTA-D10CM binding without and with co-incubation with an excess of unlabeled NOTA-D10CM. PSL/mm2 photostimulated luminescence per square millimeter. P values are from Student’s t test