Myocardial substrate and route of administration determine acute cardiac retention and lung bio-distribution of cardiosphere-derived cells
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Quantification of acute myocardial retention and lung bio-distribution of cardiosphere-derived cells (CDCs) following transplantation is important to improve engraftment.
Methods and results
We studied acute(1 hour) cardiac/lung retention in 4 groups (n = 25) of rats (normal—NL, acute ischemia-reperfusion—AI-RM, acute permanent ligation—PL, and chronic infarct by ischemia-reperfusion—CI-R) using intra-myocardial delivery, 1 group using intracoronary delivery (acute ischemia-reperfusion, AI-RC, n = 5) and 1 group using intravenous delivery (acute ischemia-reperfusion, AI-RV, n = 5) of CDCs by PET. Cardiac retention was similar in the NL, AI-RM, CI-R, and A-IRC groups (13.6% ± 2.3% vs 12.0% ± 3.9% vs 9.9 ± 2.8 vs 15.4% ± 5.5%; P = NS), but higher in PL animals (22.9% ± 5.2%; P < .05). Low cardiac retention was associated with significantly higher lung activity in NL and AI-RM groups (43.3% ± 5.6% and 39.9% ± 9.3%), compared to PL (28.5% ± 5.9%), CI-R (20.2% ± 9.3%), and A-IRC (19.9% ± 5.6%) animals (P < .05 vs AI-RM and NL). Lung activity was highest following intravenous CDC delivery (55.1% ± 9.3%, P < .001) and was associated with very low cardiac retention (0.8% ± 1.06%). Two-photon microscopy indicated that CDCs escaped to the lungs via the coronary veins following intra-myocardial injection.
Acute cardiac retention and lung bio-distribution vary with the myocardial substrate and injection route. Intra-myocardially injected CDCs escape into the lungs via coronary veins, an effect that is more pronounced in perfused myocardium.
KeywordsStem cells acute heart retention PET lung bio-distribution
We are grateful to Dana Kemmer for administrative assistance, Michelle Leppo, BS and Junaid M. Afzal, MBBS, MS for help with experiments.
Dr. Eduardo Marbán is founder and equity holder of Capricor, Inc. that works on CDCs. Capricor provided no funding for the present study. The remaining authors report no conflicts.
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