Alterations in cardiac contractile and regulatory proteins contribute to age-related cardiac dysfunction in male rats.
Physiol Rep
; 12(16): e70012, 2024 Aug.
Article
en En
| MEDLINE
| ID: mdl-39169429
ABSTRACT
Aging is associated with cardiac contractile abnormalities, but the etiology of these contractile deficits is unclear. We hypothesized that cardiac contractile and regulatory protein expression is altered during aging. To investigate this possibility, left ventricular (LV) lysates were prepared from young (6 months) and old (24 months) Fischer344 rats. There are no age-related changes in SERCA2 expression or phospholamban phosphorylation. Additionally, neither titin isoform expression nor phosphorylation differed. However, there is a significant increase in ß-isoform of the myosin heavy chain (MyHC) expression and phosphorylation of TnI and MyBP-C during aging. In permeabilized strips of papillary muscle, force and Ca2+ sensitivity are reduced during aging, consistent with the increase in ß-MyHC expression and TnI phosphorylation. However, the increase in MyBP-C phosphorylation during aging may represent a mechanism to compensate for age-related contractile deficits. In isolated cardiomyocytes loaded with Fura-2, the peak of the Ca2+ transient is reduced, but the kinetics of the Ca2+ transient are not altered. Furthermore, the extent of shortening and the rates of both sarcomere shortening and re-lengthening are reduced. These results demonstrate that aging is associated with changes in contractile and regulatory protein expression and phosphorylation, which affect the mechanical properties of cardiac muscle.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Ratas Endogámicas F344
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Envejecimiento
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Miocitos Cardíacos
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Contracción Miocárdica
Límite:
Animals
Idioma:
En
Revista:
Physiol Rep
Año:
2024
Tipo del documento:
Article
País de afiliación:
Estados Unidos
Pais de publicación:
Estados Unidos