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Updated: Mar 24, 2026
Induction of Endothelial Differentiation in Cardiac Progenitor Cells Under Low Serum Conditions
Published on: January 7, 2019
[STEM CELLS PLAY NO CONSIDERABLE ROLE IN CARDIOMYOCYTE REPOPULATION OF ADULT HUMAN HEART]
Insights
Cardiac regeneration in adult humans is limited. This study found no evidence of stem cell involvement in heart muscle renewal, suggesting hypertrophy compensates for aging. Keywords: cardiac regeneration, heart muscle, stem cells, hypertrophy.
Area of Science:
- Cardiology
- Cell Biology
- Regenerative Medicine
Context:
- Debate exists on cardiac regeneration capacity in adult humans.
- One view posits weak myocardial regeneration, while another suggests high renewal rates via resident stem cells.
Purpose:
- To investigate the role of stem cells in human myocardium repopulation across different age groups.
- To analyze cardiomyocyte size and ploidy distribution in adult male hearts aged 20-50 years.
Summary:
- Cardiomyocyte size, dry weight, and ploidy were analyzed using cytofluorimetry and interferometry in men aged 20-30 and 40-50.
- No intermediate cell volumes were found, and ploidy distribution remained constant with age.
- The number of cardiomyocytes decreased with age, and hypertrophy, not stem cell-driven regeneration, appears to compensate for aging heart function.
Impact:
- Provides evidence against stem cell involvement in human cardiac regeneration during aging.
- Suggests cardiomyocyte hypertrophy is the primary mechanism for functional compensation in the aging heart.
- Informs future research directions in cardiac aging and potential therapeutic strategies.
Abstract:
There are two viewpoints concerning cardiac regeneration. One assumes that the myocardium of an adult human heart has a weak regenerative capacity. According to another, myocardium can renew at a high rate due to the presence of resident stem cells. This study was aimed to test the role of stem cells in myocardium repopulation in adult humans of different age by examining the distribution of cardiomyocytes as to their size and ploidy. Cytofluorimetry and interferometry were used to determine the dry weight, volume and ploidy of myocytes isolated from the left ventricle of the normal heart of 12 men aged 20-30 years (n = 7) and 40-50 years (n = 5). Dry weight of cardiomyocytes made up 6906 ± 182 pg (10(-12) g) aged 20-30 years and 9126 ± 263 pg in men aged 40-50 years. There were no cells with an intermediate volume between amplifying and mature myocytes. The number of candiomyocytes in the left ventricle made up (3.18 ± 0.05) x 10(9) cells in the age group 20-30 years and (2.06 ± 0.6) x 10(9) cells in the age group 40-50 years. Most of the myocyte population was represented by mononucleate cells with tetraploid nuclei (41.3%). Proportion of myocytes of different ploidy classes did not change in the interval from 20 to 50 years. Our results strongly suggest that stem cells of the heart are not involved in the regeneration of human myocardium during aging. The function of the aging heart is mostly compensated by the hypertrophy of the remaining myocytes.
