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Updated: Aug 9, 2025
Delayed Intramyocardial Delivery of Stem Cells after Ischemia Reperfusion Injury in a Murine Model
Published on: September 3, 2020
Unlocking cardiomyocyte renewal potential for myocardial regeneration therapy
Melod Mehdipour1, Sangsoon Park1, Guo N Huang1
1Cardiovascular Research Institute and Department of Physiology, University of California, San Francisco, San Francisco, CA 94158, USA; Eli and Edythe Broad Center for Regeneration Medicine and Stem Cell Research, University of California, San Francisco, San Francisco, CA 94158, USA; Bakar Aging Research Institute, University of California, San Francisco, San Francisco, CA 94158, USA.
Insights
Mammalian heart regeneration is limited because adult cardiomyocytes stop dividing. Understanding why neonatal hearts and lower vertebrates regenerate could reveal new heart failure treatments.
Area of Science:
- Cardiovascular Biology
- Regenerative Medicine
- Comparative Physiology
Background:
- Cardiovascular disease causes irreversible cardiomyocyte loss, leading to heart failure.
- Adult mammalian hearts have minimal regenerative capacity, unlike neonatal hearts and lower vertebrates.
- Cardiomyocyte cell cycle arrest and polyploidization are key barriers to adult heart regeneration.
Purpose of the Study:
- To review mechanisms limiting adult mammalian cardiac regeneration.
- To explore differences in cardiac regeneration across species and developmental stages.
- To identify molecular targets for heart failure therapy.
Main Methods:
- Literature review of current models and research on cardiac regeneration.
- Analysis of factors contributing to loss of regenerative potential in adult mammals.
- Discussion of signaling pathways controlling cardiomyocyte proliferation and polyploidization.
Main Results:
- Adult mammalian heart regeneration is hindered by factors including environmental oxygen, endothermy, immune system complexity, and cancer risk tradeoffs.
- Conflicting reports exist regarding extrinsic and intrinsic signaling pathways influencing cardiomyocyte cell cycle dynamics.
- Neonatal mammals and lower vertebrates exhibit robust cardiomyocyte regenerative capabilities.
Conclusions:
- Understanding the physiological brakes on cardiac regeneration is crucial for developing novel therapeutic strategies.
- Identifying molecular targets could lead to treatments for heart failure by enhancing myocardial repair.
- Comparative analysis across phylogeny and ontogeny offers insights into regenerative potential.
Abstract:
Cardiovascular disease remains the leading cause of mortality worldwide. Cardiomyocytes are irreversibly lost due to cardiac ischemia secondary to disease. This leads to increased cardiac fibrosis, poor contractility, cardiac hypertrophy, and subsequent life-threatening heart failure. Adult mammalian hearts exhibit notoriously low regenerative potential, further compounding the calamities described above. Neonatal mammalian hearts, on the other hand, display robust regenerative capacities. Lower vertebrates such as zebrafish and salamanders retain the ability to replenish lost cardiomyocytes throughout life. It is critical to understand the varying mechanisms that are responsible for these differences in cardiac regeneration across phylogeny and ontogeny. Adult mammalian cardiomyocyte cell cycle arrest and polyploidization have been proposed as major barriers to heart regeneration. Here we review current models about why adult mammalian cardiac regenerative potential is lost including changes in environmental oxygen levels, acquisition of endothermy, complex immune system development, and possible cancer risk tradeoffs. We also discuss recent progress and highlight conflicting reports pertaining to extrinsic and intrinsic signaling pathways that control cardiomyocyte proliferation and polyploidization in growth and regeneration. Uncovering the physiological brakes of cardiac regeneration could illuminate novel molecular targets and offer promising therapeutic strategies to treat heart failure.
