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Updated: Aug 10, 2026
Intramyocardial Cell Delivery: Observations in Murine Hearts
Published on: January 24, 2014
Optimal time for cardiomyocyte transplantation to maximize myocardial function after left ventricular injury
R K Li1, D A Mickle, R D Weisel
1Division of Cardiac Surgery, Toronto Hospital Research Institute, and Toronto General Hospital, Ontario, Canada. renke.li@uhn.on.ca
Background:
This study was designed to determine the optimal time for cell transplantation after myocardial injury.
Methods:
The left ventricular free wall of adult rat hearts was cryoinjured and the animals were sacrificed at 0, 1, 2, 4, and 8 weeks for histologic studies. Fetal rat cardiomyocytes (transplant) or culture medium (control) were transplanted immediately (n = 8), 2 weeks (n = 8), and 4 weeks (n = 12) after cryoinjury. At 8 weeks, rat heart function, planimetry, and histologic studies were performed.
Results:
Cryoinjury produced a transmural injury. The inflammatory reaction was greatest during the first week but subsided during the second week after cryoinjury. Scar size expanded (p < 0.01) at 4 and 8 weeks. Cardiomyocytes transplanted immediately after cryoinjury were not found 8 weeks after cryoinjury. Scar size and myocardial function were similar to the control hearts. Cardiomyocytes transplanted at 2 and 4 weeks formed cardiac tissue within the scar, limited (p < 0.01) scar expansion, and had better (p < 0.001) heart function than the control groups. Developed pressure was greater (p < 0.01) in the hearts with transplanted cells at 2 weeks than at 4 weeks.
Conclusions:
Cardiomyocyte transplantation was most successful after the inflammatory reaction resolved but before scar expansion.
