TY - JOUR
T1 - Myocyte repolarization modulates myocardial function in aging dogs
AU - Sorrentino, Andrea
AU - Signore, Sergio
AU - Qanud, Khaled
AU - Borghetti, Giulia
AU - Meo, Marianna
AU - Cannata, Antonio
AU - Zhou, Yu
AU - Wybieralska, Ewa
AU - Luciani, Marco
AU - Kannappan, Ramaswamy
AU - Zhang, Eric
AU - Matsuda, Alex
AU - Webster, Andrew
AU - Cimini, Maria
AU - Kertowidjojo, Elizabeth
AU - D’Alessandro, David A.
AU - Wunimenghe, Oriyanhan
AU - Michler, Robert E.
AU - Royer, Christopher
AU - Goichberg, Polina
AU - Leri, Annarosa
AU - Barrett, Edward G.
AU - Anversa, Piero
AU - Hintze, Thomas H.
AU - Rota, Marcello
N1 - Publisher Copyright:
© 2016 the American Physiological Society.
PY - 2016/4
Y1 - 2016/4
N2 - Studies of myocardial aging are complex and the mechanisms involved in the deterioration of ventricular performance and decreased functional reserve of the old heart remain to be properly defined. We have studied a colony of beagle dogs from 3 to 14 yr of age kept under a highly regulated environment to define the effects of aging on the myocardium. Ventricular, myocardial, and myocyte function, together with anatomical and structural properties of the organ and cardiomyocytes, were evaluated. Ventricular hypertrophy was not observed with aging and the structural composition of the myocardium was modestly affected. Alterations in the myocyte compartment were identified in aged dogs, and these factors negatively interfere with the contractile reserve typical of the young heart. The duration of the action potential is prolonged in old cardiomyocytes contributing to the slower electrical recovery of the myocardium. Also, the remodeled repolarization of cardiomyocytes with aging provides inotropic support to the senescent muscle but compromises its contractile reserve, rendering the old heart ineffective under conditions of high hemodynamic demand. The defects in the electrical and mechanical properties of cardiomyocytes with aging suggest that this cell population is an important determinant of the cardiac senescent phenotype. Collectively, the delayed electrical repolarization of aging cardiomyocytes may be viewed as a critical variable of the aging myopathy and its propensity to evolve into ventricular decompensation under stressful conditions.
AB - Studies of myocardial aging are complex and the mechanisms involved in the deterioration of ventricular performance and decreased functional reserve of the old heart remain to be properly defined. We have studied a colony of beagle dogs from 3 to 14 yr of age kept under a highly regulated environment to define the effects of aging on the myocardium. Ventricular, myocardial, and myocyte function, together with anatomical and structural properties of the organ and cardiomyocytes, were evaluated. Ventricular hypertrophy was not observed with aging and the structural composition of the myocardium was modestly affected. Alterations in the myocyte compartment were identified in aged dogs, and these factors negatively interfere with the contractile reserve typical of the young heart. The duration of the action potential is prolonged in old cardiomyocytes contributing to the slower electrical recovery of the myocardium. Also, the remodeled repolarization of cardiomyocytes with aging provides inotropic support to the senescent muscle but compromises its contractile reserve, rendering the old heart ineffective under conditions of high hemodynamic demand. The defects in the electrical and mechanical properties of cardiomyocytes with aging suggest that this cell population is an important determinant of the cardiac senescent phenotype. Collectively, the delayed electrical repolarization of aging cardiomyocytes may be viewed as a critical variable of the aging myopathy and its propensity to evolve into ventricular decompensation under stressful conditions.
KW - Aging
KW - Contractile reserve
KW - Myocardium
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U2 - 10.1152/ajpheart.00682.2015
DO - 10.1152/ajpheart.00682.2015
M3 - Article
C2 - 26801307
AN - SCOPUS:84983775755
SN - 0363-6135
VL - 310
SP - H873-H890
JO - American Journal of Physiology - Heart and Circulatory Physiology
JF - American Journal of Physiology - Heart and Circulatory Physiology
IS - 7
ER -