title: Effect of age on the development of cardiac hypertrophy produced by aortic constriction in the rat.
abstract: To test the hypothesis that the capacity to develop left ventricular (LV) hypertrophy might diminish with advancing age, we examined the hypertrophic response to ascending aortic constriction in 3 groups of adult Fischer 344 rats (9 months, 18 months, and 22 months of age). Aortic constriction was created so that aortic cross-sectional areas would be the same for the 3 groups of rats. Four weeks after imposition of aortic constriction, there was no significant difference in peak LV pressure, peak-to-peak and mean systolic pressure gradients between left ventricle and aorta, cardiac output, LV minute work, or cross-sectional area of the aortic constrictions in the 3 groups. In 9-month-old aortic-constricted rats, LV dry wt (LVDW)/body wt, LVDW/tibial length, and myocyte width increased by 23% (p less than 0.01), 14% (p less than 0.01), and 27% (p less than 0.01), respectively, compared with sham-operated rats. In contrast, in 18-month-old and 22-month-old aortic-constricted rats, LVDW/body wt and LVDW/tibial length were unchanged compared with sham-operated controls, and increases in myocyte width were only modest 4 weeks following constriction. RNA concentration in the myocardium 5 days after constriction increased by 21% (p less than 0.001) in 9-month-old rats but showed no significant rise in 18-month-old rats. These results suggest that advancing age is associated with a diminished capacity to develop myocardial hypertrophy in response to acute pressure overload and that a reduced ability to synthesize protein may be one of the major contributing factors to a diminished capacity for hypertrophy in advanced age.
mesh_terms: D000375:Aging / Q000502:physiology*; D000818:Animals; D001018:Aortic Diseases / Q000150:complications*; D006332:Cardiomegaly / Q000209:etiology* / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology; D003251:Constriction, Pathologic; D006439:Hemodynamics; D008297:Male; D009206:Myocardium / Q000378:metabolism / Q000473:pathology; D009929:Organ Size; D009994:Osmolar Concentration; D012313:RNA / Q000378:metabolism; D051381:Rats; D011916:Rats, Inbred F344
chemical_list: D012313:RNA