Dual channel optical tomographic imaging of leukocyte recruitment and protease activity in the healing myocardial infarct

Inflammatory responses after myocardial infarction profoundly impact tissue repair. Yet, efficient tools to serially and noninvasively assess cellular and molecular functions in postinfarct inflammation are lacking. Here we use multichannel fluorescent molecular tomography (FMT) for spatiotemporal resolution of phagocytic and proteolytic activities mediated by macrophages and neutrophils in murine infarcts. We performed FMT imaging to compare the course of efficient and impaired healing in wild-type and FXIII-/- mice, respectively. Mice subjected to coronary ligation received simultaneous injections with Prosense-680, an activatable fluorescence sensor reporting on cathepsin activity, and CLIO-VT750, a magneto-fluorescent nanoparticle for imaging of phagocyte recruitment. On FMT, Prosense-680 infarct signal was 19-fold higher than background (P