Related Experiment Video
Updated: Aug 13, 2026
Simultaneous Assessment of Cardiomyocyte DNA Synthesis and Ploidy: A Method to Assist Quantification of Cardiomyocyte Regeneration and Turnover
Published on: May 23, 2016
Quantitative Three-dimensional Label-free Digital Holographic Imaging of Cardiomyocyte Size, Ploidy, and Cell
Insights
Newborn cardiomyocyte proliferation is lost post-birth as cells become binucleated. Digital holographic imaging shows mononucleated cells divide readily, while binucleated cells have limited division potential, impacted by cell size and ploidy.
Area of Science:
- Cardiovascular Biology
- Cell Biology
- Developmental Biology
Background:
- Mammalian cardiac regeneration is lost shortly after birth.
- Cardiomyocytes transition from hyperplasia to hypertrophy, withdrawing from the cell cycle and becoming binucleated.
- The impact of cardiomyocyte size and ploidy on cell division is poorly understood.
Approach:
- Utilized digital holographic imaging (Holomonitor M4) for label-free, real-time, 3D tracking of primary cardiomyocytes.
- Quantitatively analyzed cardiomyocyte dynamics, including volume and ploidy, with single-cell resolution.
- Evaluated the proliferative responses of mononucleated diploid and binucleated tetraploid cardiomyocytes.
Key Points:
- Mononucleated cardiomyocytes exhibit significant proliferative potential and divide frequently.
- Binucleated cardiomyocytes show a blunted proliferative response, with most not dividing, though some retain limited capacity.
- Both cell types reach a specific size threshold before division, which is elevated in binucleated cells.
Conclusions:
- Cardiomyocyte binucleation and increased size contribute to the loss of regenerative capacity after birth.
- Understanding the interplay between cardiomyocyte size, ploidy, and cell cycle control is crucial for cardiac regeneration research.
- Digital holographic imaging offers a powerful tool for studying cardiomyocyte dynamics and cell cycle regulation.
Abstract:
Cardiac regeneration in newborn rodents depends on the ability of pre-existing cardiomyocytes to proliferate and divide. This capacity is lost within the first week of postnatal development when these cells rapidly switch from hyperplasia to hypertrophy, withdraw from the cell cycle, become binucleated, and increase in size. How these dynamic changes in size and ploidy impact cardiomyocyte proliferative potential is not well understood. In this study, we innovate the application of a commercially available digital holographic imaging microscope, the Holomonitor M4, to evaluate the proliferative responses of mononucleated diploid and binucleated tetraploid cardiomyocytes. This instrument coupled with the powerful Holomonitor App Suite software enables long-term label-free quantitative three-dimensional tracking of primary cardiomyocyte dynamics in real-time with single-cell resolution. Our digital holographic imaging results provide direct evidence that mononucleated cardiomyocytes retain significant proliferative potential as most can successfully divide with high frequency. In contrast, binucleated cardiomyocytes exhibit a blunted response to a proliferative stimulus with the majority not attempting to divide at all. Nevertheless, some binucleated cardiomyocytes were capable of complete division, suggesting that these cells still do retain limited proliferative capacity. By quantitatively tracking cardiomyocyte volume dynamics during these proliferative responses, we reveal that both mononucleated and binucleated cells reach a unique size threshold prior to attempted cell division. The absolute threshold is increased by binucleation, which may limit the ability of binucleated cardiomyocytes to divide. By defining the interrelationship between cardiomyocyte size, ploidy, and cell cycle control, we will better understand the cellular mechanisms that drive the loss of mammalian cardiac regenerative capacity after birth.
