Expression of Contractile Proteins in the Heart Changes with Age
The expression of contractile proteins in the heart undergoes changes as we age, affecting the ability of muscle cells to respond to nervous system signals. Research reveals a shift in the balance of key contractile proteins, potentially leading to decreased effectiveness. This alteration may contribute to age-related declines in heart muscle function, although it could be a secondary factor. Investigating this in mice through genetic manipulation could provide valuable insights.
Studies indicate that aging alters the expression of cardiac contractile and regulatory proteins, contributing to age-related contractile impairments. Notably, aging leads to increased levels of cardiac myosin heavy chain β (β-MyHC) and the phosphorylation of troponin I (TnI) and myosin-binding protein C (MyBP-C). This shift towards β-MyHC, a less efficient variant, may impact muscle contraction dynamics negatively. Further research shows that this change could result in decreased force output and slower contraction rates in aging hearts.
The higher expression of α-MyHC, a more efficient variant, in young hearts suggests superior contractile performance compared to β-MyHC. Aging-related increase in β-MyHC expression, therefore, may lead to reduced muscle function. Additionally, aging is associated with enlarged myocytes and cardiac fibrosis, which further affects contractility. These findings highlight the complex interplay between contractile protein expression, muscle function, and aging in the heart.
Link: https://doi.org/10.14814/phy2.70012
