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Alpha-skeletal actin messenger RNA increases in acute right ventricular hypertrophy
P R Bakerman1, K R Stenmark, J H Fisher
1Cardiovascular Pulmonary Research Laboratory, Webb-Waring Lung Institute, University of Colorado Health Sciences Center, Denver 80201.
The American Journal of Physiology
|April 1, 1990
Summary
Newborn calves exposed to hypobaric hypoxia showed significant changes in right ventricular gene expression. Specifically, alpha-skeletal actin mRNA increased, indicating a potential shift in heart muscle cell characteristics.
Area of Science:
- Cardiovascular Physiology
- Molecular Biology
- Neonatal Medicine
Background:
- Hypobaric hypoxia in newborn calves leads to pulmonary hypertension.
- This hypertension causes right ventricular hypertrophy and potential failure.
- Changes in contractile protein gene expression may reflect myocyte alterations.
Purpose of the Study:
- To investigate alterations in contractile actin isotype gene expression in the right ventricle (RV) and left ventricle (LV) of newborn calves.
- To determine if hypobaric hypoxia induces changes in alpha-skeletal and alpha-cardiac actin mRNA levels.
- To assess the persistence of these changes after hypoxic exposure.
Main Methods:
- Measurement of alpha-skeletal and alpha-cardiac actin mRNA levels using total cellular RNA.
- Comparison between RV and LV tissues from hypoxic calves and age-matched controls.
- Analysis of gene expression after 2 weeks of hypoxia, 2 days after removal, and 30 days after removal.
Main Results:
- A greater than 10-fold increase in alpha-skeletal actin mRNA was observed in the RV of hypertensive calves.
- Alpha-cardiac actin mRNA levels remained unchanged in the RV and LV.
- RV alpha-skeletal actin mRNA decreased post-hypoxia but remained elevated, suggesting a persistent change.
Conclusions:
- Hypobaric hypoxia induces a significant alteration in the RV myocyte phenotype in newborn calves.
- The increased expression of alpha-skeletal actin mRNA points to a potential shift in the cellular characteristics of the right ventricle.
- The long-term physiological significance of this altered myocyte phenotype requires further investigation.
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