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Age is a risk factor for maladaptive changes in rats exposed to increased pressure loading of the right ventricular myocardium

Published online by Cambridge University Press:  23 March 2007

Vladimiro L. Vida
Affiliation:
Department of Pediatric Cardiac Surgery, University of Padua, Italy
Annalisa Angelini
Affiliation:
Department of Pathology, University of Padua, Italy
Simonetta Ausoni
Affiliation:
Department of Biomedical Sciences, University of Padua, Italy
Alessandra Bilardi
Affiliation:
Department of Biomedical Sciences, University of Padua, Italy
Carlo Ori
Affiliation:
Department of Anesthesia, University of Padua, Italy
Francesca Vlassich
Affiliation:
Department of Anesthesia, University of Padua, Italy
Valentina Zoso
Affiliation:
Department of Anesthesia, University of Padua, Italy
Ornella Milanesi
Affiliation:
Department of Pediatrics, University of Padua, Italy
Saverio Sartore
Affiliation:
Department of Biomedical Sciences, University of Padua, Italy
Mila della Barbera
Affiliation:
Department of Pathology, University of Padua, Italy
Tania Zaglia
Affiliation:
Department of Biomedical Sciences, University of Padua, Italy
Gaetano Thiene
Affiliation:
Department of Pathology, University of Padua, Italy
Giovanni Stellin
Affiliation:
Department of Pediatric Cardiac Surgery, University of Padua, Italy

Abstract

Objective: To study the adaptive potential of the right ventricular myocardium after 30 days of mechanical-induced overload in rats from two different age groups. Materials and methods: We banded the pulmonary trunk, so as to increase the systolic work load of the right ventricle, in 19 adult Sprague-Dawley rats at the age of 10 weeks, and 16 weanlings when they were 3 weeks-old, using 10 adults and 10 weanlings as controls. We analysed the functional adaptation and structural changes of the right ventricular myocardium, blood vessels and interstitial tissue after 30 days of increased afterload. Results: The increased workload induced an increase of the right ventricular weight and free wall thickness in animals from both age groups when compared to controls. These changes were mostly related to cardiomyocytic hypertrophy, as confirmed by the expression of myocardial hypertrophic markers, without any apparent increase of their number, a “reactive” fibrosis especially evident in the adult rats, with p-value less than 0.0001, and a more extensive neocapillary network in the weanlings compared to the adults aubsequent to banding, the p-value being less than 0.0001. Conclusion: In response to right ventricular afterload, weanlings showed a higher adaptive capillary growth, which hampered the development of fibrosis as seen in the adult rats. Age seems to be a risk factor for adverse structural-functional changes of right ventricle subjected to increased workload.

Type
Original Article
Copyright
© 2007 Cambridge University Press

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