Related Experiment Video
Updated: Jun 6, 2026

Simultaneous Assessment of Cardiomyocyte DNA Synthesis and Ploidy: A Method to Assist Quantification of Cardiomyocyte Regeneration and Turnover
Published on: May 23, 2016
Myocyte turnover in the aging human heart.
Jan Kajstura1, Narasimman Gurusamy, Barbara Ogórek
1Department of Anesthesia and Medicine and Cardiovascular Division, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA. jkajstura@partners.org
The aging female heart shows superior cardiomyocyte regeneration compared to males, with human cardiac stem cells (hCSCs) playing a key role in maintaining cardiac health and slowing aging.
Area of Science:
- Cardiovascular Biology
- Gerontology
- Stem Cell Research
Background:
- The rate of cardiomyocyte turnover in aging human hearts, considering sex differences, remains largely uncharacterized.
- Understanding myocardial aging is crucial for defining human cardiac biology.
Purpose of the Study:
- To investigate the impact of age and sex on myocyte regeneration rates.
- To determine the origin of newly formed cardiomyocytes in the aging human heart.
Main Methods:
- Analysis of myocyte replacement, cellular senescence, and apoptosis in human hearts from female (n=32) and male (n=42) donors aged 19-104 years.
- Measurement of telomere length in human cardiac stem cells (hCSCs) and newly formed cardiomyocytes.
Main Results:
- Aging leads to telomere shortening in hCSCs, with new cardiomyocytes inheriting shorter telomeres and exhibiting senescence.
- Female hearts demonstrate a greater capacity to manage age-related myopathy, possessing more functional hCSCs and younger myocytes than male hearts.
- Myocyte turnover is higher in females (10-40% annually) than males (7-32% annually) across the lifespan, with the female myocyte compartment replaced 15 times versus 11 times in males from age 20 to 100.
Conclusions:
- The human heart is a dynamic organ influenced by resident hCSCs.
- hCSCs regulate cardiac homeostasis and the aging process of the heart.
Related Concept Videos
Specialized Characteristics of Cardiac Muscles
Cardiac muscle cells are smaller than skeletal muscles, averaging 10–20 mm in diameter and 50–100 mm in length. However, they have large energy demands for continuous contraction and relaxation. This energy is almost exclusively derived from aerobic metabolism of energy reserves in...
Structure of Cardiac Muscles
Compared to skeletal muscles, cardiac muscle cells are small and mostly have a single nucleus. Additionally, they are usually...
Mitochondria

