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Updated: Jun 22, 2026
Intramyocardial Cell Delivery: Observations in Murine Hearts
Published on: January 24, 2014
Improvement of mouse cardiac function by hESC-derived cardiomyocytes correlates with vascularity but not graft size
Linda W van Laake1, Robert Passier, Krista den Ouden
1Heart Lung Center Utrecht, The Netherlands.
Insights
Transplanting human embryonic stem cell-derived cardiomyocytes (hESC-CM) improves heart function after myocardial infarction (MI). Smaller grafts showed better outcomes, suggesting focus on delivery strategies over graft size.
Area of Science:
- Cardiovascular Research
- Regenerative Medicine
- Stem Cell Biology
Background:
- Human embryonic stem cell-derived cardiomyocytes (hESC-CM) show potential for treating myocardial infarction (MI).
- Optimal cell delivery and underlying mechanisms for hESC-CM transplantation remain unclear.
Purpose of the Study:
- Investigate the impact of injected cell number and graft size on cardiac function post-MI.
- Elucidate the role of paracrine mechanisms and vascularization in hESC-CM therapy.
Main Methods:
- Myocardial infarction (MI) induced in NOD-SCID mice, followed by injection of varying doses of hESC-CM.
- Cardiac function assessed using 9.4 T MRI over 12 weeks.
- Graft characterization, vascularity, and paracrine effects analyzed via immunofluorescence and immunohistochemistry.
Main Results:
- hESC-CM transplantation improved cardiac performance and survival in the short, mid, and long term.
- Enhanced vascular density around grafts correlated with improved cardiac function at 4 weeks.
- Larger graft size was associated with reduced functional improvement, despite increased vascularization.
Conclusions:
- hESC-CM transplantation enhances myocardial vascularization and cardiac function post-MI.
- Optimal therapeutic outcomes depend on graft size and delivery, not solely cell number.
- Future research should prioritize advanced delivery methods and understanding mechanisms over maximizing graft size.
Abstract:
Transplantation of human embryonic stem cell-derived cardiomyocytes (hESC-CM) has been shown to improve the function of the rodent heart 1 month after myocardial infarction (MI). However, the mechanistic basis and optimal delivery strategies are unclear. We investigated the influence of the number of injected cells, resulting graft size, and possible paracrine mechanisms in this process. MI was induced in NOD-SCID mice (n=84) followed by injection of enriched hESC-CM at different dosages, hESC-non-CM derivatives, culture medium, or no injection. Cardiac function was monitored for 12 weeks with 9.4 T MRI (n=70). Grafts were identified by epifluorescence of a transgenic GFP marker and characterized by immunofluorescence. Vascularity and paracrine effects were investigated immunohistochemically. Transplantation of differentiated hESCs improved short, mid-, and long-term cardiac performance and survival, although only cardiomyocytes formed grafts. A mid-term (4 weeks) cardiomyocyte-specific enhancement was associated with elevated vascular density around the graft and attenuated compensatory remodeling. However, increasing the number of hESC-CM for injection did not enhance heart function further. Moreover, we observed that small graft size was associated with a better functional outcome. HESC-CM increased myocardial vascularization and enhanced heart function in mice after MI, but larger graft size was associated with reduced functional improvement. Future studies should focus on advanced delivery strategies and mechanisms of action rather than increasing graft size.
