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Proliferating cells in adult cardiomyopathic hamster ventricles
A Carbone1, M Minieri, P Di Nardo
1Department of Internal Medicine, University of Rome, Tor Vergata, Roma, Italy.
Insights
In hereditary hypertrophic cardiomyopathy, actively proliferating cells in the heart muscle express muscular markers. This suggests these cells may originate from muscle tissue and contribute to cardiomyopathy development.
Area of Science:
- Cardiovascular Biology
- Cellular and Molecular Medicine
- Genetics and Disease
Background:
- Hereditary hypertrophic cardiomyopathy is characterized by abnormal heart muscle growth.
- Early cellular events leading to cardiomyopathy are not fully understood.
- UM.X7.1 hamsters serve as a model for studying hypertrophic cardiomyopathy.
Purpose of the Study:
- To investigate the cellular origin and characteristics of proliferating cells in the myocardium of hypertrophic cardiomyopathic hamsters.
- To determine if these proliferating cells are of muscular origin and contribute to cardiomyopathy pathogenesis.
Main Methods:
- Immunohistochemical analysis of myocardial tissue from UM.X7.1 hamsters at 60-90 days of life.
- Detection of muscular markers (desmin, alpha-sarcomeric actin, myoglobin, alpha/gamma-smooth muscle actin) in proliferating cells.
Main Results:
- Large clusters of actively proliferating cells with a rhabdoid appearance were observed in the myocardium.
- Most proliferating cells expressed muscular markers, albeit with variable patterns.
- These findings suggest a muscular origin for the proliferating cells.
Conclusions:
- Proliferating cells in the myocardium of cardiomyopathic hamsters appear to be of muscular origin.
- Cellular proliferation is a key pathophysiological step in the development of hereditary hypertrophic cardiomyopathy.
- The origin of these cells may involve de-differentiated adult cardiomyocytes or immature fetal cardiomyocytes.
Abstract:
Myocardium of hereditary hypertrophic cardiomyopathic hamsters UM.X7.1 between 60 and 90 days of life shows large clusters of densely packed, actively proliferating cells with a rhabdoid appearance. Immunohistochemical studies showed that most of proliferating cells express, although with variable patterns, muscular markers such as desmin, alpha-sarcomeric actin, myoglobin and alpha/gamma-smooth muscle actin. The simultaneous occurrence of a poorly differentiated appearance, intense proliferating activity and expression of muscular markers seems to indicate that cluster cells may be muscular in origin and that their proliferation can be a fundamental pathophysiological step in the onset of cardiomyopathy. The possibility that myocardial proliferating cells originated from de-differentiated adult cardiomyocytes, which undergo a short cellular proliferation program, or from not fully matured (fetal) cardiomyocytes scattered throughout the myocardium is discussed.