Key result
Pulmonary trunk banding induced reactive fibrosis in adult rats (P<0.0001) and a more extensive neocapillary network in weanlings (P<0.0001), suggesting age influences right ventricular adaptation.
Why the study?
Does age influence the structural and functional adaptation of the right ventricular myocardium to mechanical-induced overload in rats?
Does age influence the structural and functional adaptation of the right ventricular myocardium to mechanical-induced overload in rats?
p-value: p=<0.0001
Younger age in rats is associated with better adaptive capillary growth and less fibrosis in response to right ventricular pressure overload compared to adults.
Age-dependent RV adaptation in rats is hypothesis-generating; leaves open translation to clinical congenital heart disease management.
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.
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Vida et al. (2007) studied Right ventricular myocardium mechanical-induced overload (n=55). Pulmonary trunk banding vs. Unbanded controls was evaluated on Functional adaptation and structural changes of the right ventricular myocardium, blood vessels and interstitial tissue (p=<0.0001). Pulmonary trunk banding induced reactive fibrosis in adult rats (P<0.0001) and a more extensive neocapillary network in weanlings (P<0.0001), suggesting age influences right ventricular adaptation.
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