Key result
Advanced age significantly decreased maximum Ca2+-ATPase activity in rat heart sarcoplasmic reticulum to 64.5% of adult values, which was associated with protein oxidative damage rather than altered protein expression.
Effect estimate: decreased to 64.5% of adult values
Absolute Event Rate: 327.3% vs 507.4%
p-value: p=<0.001
Age-related alterations in myocardial relaxation may be driven by oxidative modifications of sarcoplasmic reticulum proteins rather than decreased expression of calcium handling proteins.
May implicate oxidative SR damage in age-related relaxation impairment; hypothesis-generating in rats, leaves open human relevance.
Altered Ca(2+) handling may be responsible for the development of cardiac contractile dysfunctions with advanced age. In the present study, we investigated the roles of oxidative damage to sarcoplasmic reticulum (SR) and expression of Ca(2+)-ATPase (SERCA 2a) and phospholamban in age-associated dysfunction of cardiac SR. SR vesicles were prepared from hearts of 2-, 6-, 15-, and 26-month-old Wistar rats. Although activity of Ca(2+)-ATPase decreased with advancing age, no differences in relative amounts of SERCA 2a and phospholamban protein were observed. On the other hand, significant accumulation of protein oxidative damage occurred with aging. The results of this study suggest that age-related alteration in Ca(2+)-ATPase activity in the rat heart is not a consequence of decreased protein levels of SERCA 2a and phospholamban, but could arise from oxidative modifications of SR proteins. Cellular oxidative damage caused by reactive oxygen species could contribute to age-related alternations in myocardial relaxation.
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Babušíková et al. (2012) studied Aging-related cardiac sarcoplasmic reticulum dysfunction (n=32). Advanced age vs. Adult (6-month-old) rats was evaluated on Maximum Ca2+-ATPase activity (Vmax) in nmol Pi/min/mg (decreased to 64.5% of adult values, p=<0.001). Advanced age significantly decreased maximum Ca2+-ATPase activity in rat heart sarcoplasmic reticulum to 64.5% of adult values, which was associated with protein oxidative damage rather than altered protein expression.
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