Extract

We appreciate very much the distinctive comments regarding the hypothesis of an altered calcium-regulatory system in Tako-Tsubo cardiomyopathy.1 Once again, the points raised by Nikus et al. emphasize the central role of catecholamines in an oestrogen-deficient situation. Moreover, the shown cardioregulatory role of the female sex hormones might contribute to the sudden occurrence of this disorder after an emotional or physical stress event and its unexplained disappearance after several days, which has aroused great interest in the cardiology community.

As published by Grohe et al.,2 the expression of oestrogen receptor on cardiac myocytes might explain a direct effect of female hormones on cardiac contractility. Additionally, Bupha-Intr and Wattanapermpool3 showed the physiological significance of ovarian sex hormones in the regulation of the calcium uptake in myocytes. In ovariectomized rats, the sarcolemic Ca2+-ATPase (SERCA2a) expression was remarkably downregulated in comparison to sham animals. Moreover, the activity of the calcium pump was reduced due to dephosphorylated phospholamban (PLN). Indeed, the Tako-Tsubo cardiomyopathy is characterized by a similar phenomenon.1 However, whether the deficiency of ovarian sex hormones might cause or rather potentiate this disturbance has to be evaluated.

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