In vivo myocardial distribution of multipotent progenitor cells following intracoronary delivery in a swine model of myocardial infarction

Using an anterior MI swine model, near-infrared (NIR) fluorescence was used for in vivo tracking of labelled MPCs (mesenchymal stromal (MSCs), bone marrow mononuclear (BMMNCs), and peripheral blood mononuclear (PBMNCs)) cells early after IC injection. Signal intensity ratios (SIRs) of injected over non-injected (reference) zones were used to report NIR fluorescence emission. Following IC injection, significant differences in mean SIR were documented when MSCs were compared with BMMNCs (1.28+ 0.10 vs. 0.77+ 0.11, P , 0.001; 95% CI (0.219, 0.805), respectively) or PBMNCs (1.28+ 0.10 vs. 0.80+ 0.14, P ¼ 0.005; 95% CI (0.148, 0.813), respectively). Differences were maintained during the 60 min tracking period, with only the MSC-injected groups continuously emitting NIR fluorescence (SIR.1). This is correlated with greater cell retention for MSCs relative to mononuclear cells. However, there was evidence of MSC-related vessel plugging in some swine. Conclusion Our in vivo NIR fluorescence findings suggest that MPC distribution and retention immediately after intracoronary delivery vary depending on cell population and could potentially impact the clinical efficacy of cardiac cell therapy.