title: Age is a risk factor for maladaptive changes in rats exposed to increased pressure loading of the right ventricular myocardium.
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.
  
  
  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.
  
  
  CONCLUSIONS
  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.
authors: Department of Pediatric Cardiac Surgery, University of Padua, Padua, Italy. vladimirovida@interfree.it
authors: Vladimiro L
authors: VL
authors: Vida
authors: Annalisa
authors: A
authors: Angelini
authors: Simonetta
authors: S
authors: Ausoni
authors: Alessandra
authors: A
authors: Bilardi
authors: Carlo
authors: C
authors: Ori
authors: Francesca
authors: F
authors: Vlassich
authors: Valentina
authors: V
authors: Zoso
authors: Ornella
authors: O
authors: Milanesi
authors: Saverio
authors: S
authors: Sartore
authors: Mila
authors: M
authors: della Barbera
authors: Tania
authors: T
authors: Zaglia
authors: Gaetano
authors: G
authors: Thiene
authors: Giovanni
authors: G
authors: Stellin
mesh_terms: D000367:Age Factors; D000818:Animals; D015153:Blotting, Western; D004195:Disease Models, Animal; D004452:Echocardiography; D005500:Follow-Up Studies; D006352:Heart Ventricles / Q000000981:diagnostic imaging / Q000378:metabolism / Q000473:pathology*; D017380:Hypertrophy, Right Ventricular / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology*; D008297:Male; D009124:Muscle Proteins / Q000378:metabolism; D009200:Myocardial Contraction / Q000502:physiology; D009206:Myocardium / Q000378:metabolism / Q000473:pathology*; D005082:Physical Exertion / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012307:Risk Factors; D016278:Ventricular Function, Right / Q000502:physiology*; D017725:Ventricular Pressure / Q000502:physiology*
chemical_list: D009124:Muscle Proteins