Macrophages are innate immune cells that defend the host against injury and infection are present in all organs. In the vasculature and heart, inflammatory macrophages also propel cardiovascular diseases and enhance tissue damage. In this study, confocal microscopy, flow cytometry, and in vivo positron emission tomography (PET) imaging were used, in order to assess the quantitative noninvasive assessment of pulmonary, arterial, and cardiac macrophages using the nano tracer 64Cu-Macrin.
PET imaging using 64Cu-Macrin reported the accumulation of macrophages in the lung and heart of mice with pneumonia, myocardial infarction, or sepsis. Confocal microscopy and flow cytometry detected the VT680Macrin in tissue macrophages. Upon the intravenous administration of 64Cu-Macrin in pigs and rabbits, a few changes were detected. The observations made were atherosclerotic plaques, inflamed lung regions, heightened macrophage numbers in the infarcted myocardium using a clinical PET/MRI scanner. Toxicity studies in human and rats dosimetry estimates suggest that 64Cu-Macrin is safe for human use.
In conclusion, these collective results indicate that 64Cu-Macrin could serve as a facile PET nano tracer to survey spatiotemporal macrophage dynamics during various physiological and pathological conditions. The 64Cu-Macrin PET imaging could well assist disease management, stage inflammatory CVD activity, and serve as a biomarker for upcoming macrophage-targeted therapeutics.
Ref: https://www.ahajournals.org/doi/10.1161/CIRCIMAGING.120.010586
