The translocation of marrow MNCs after experimental myocardial cryoinjury is proportional to the infarcted area

BACKGROUND: The selective homing of peripherally injected marrow MNCs (MMNCs) has recently been demonstrated in a model of cryodamaged heart. However, the mechanism underlying this phenomenon is still unknown. In the hypothesis that this process is related to the necrotic area extension, the infarcted area was correlated with the number of homed MMNCs in a model of experimental cryodamaged heart. STUDY DESIGN AND METHODS: A total of 12 donor and 12 recipient inbred isogenic adult (4 weeks old) Fisher rats were used to mimic autologous transplantation. Myocardial damage was obtained in recipient rats by cryoinjury. MMNCs were purified, labeled with PKH26 (a red fluorescent cell dye), and infused 7 days after the injury through the femoral vein of recipient rats. One week after peripheral administration, the number of homed MMNCs was assessed and the infarct size was correlated with the number of cells present in the target. RESULTS: Labeled cells were found only in the injured myocardium of the treated animals (n = 6), where a mean of 12 ± 3 PKH26+ cells per section examined were found; a significant correlation was found between the infarct size and the estimated number of cells (p = 0.008) CONCLUSION: These data indicate that the homing of MMNCs is related to the extent of the myocardial injury, suggesting that cellular therapy for regeneration of damaged myocardium should be individualized by taking into consideration the extension of the area to repair.