National and Kapodistrian University of Athens, Laboratory of Pharmacology, Faculty of Pharmacy, Panepistimiopolis, Zografou, Athens 15771, Greece.
Center of Cardiology, Cardiology 2, University Medical Center of the Johannes Gutenberg-University Mainz, 55131 Mainz, Germany.
Cardiovasc Res. 2020 Mar 1;116(3):576-591. doi: 10.1093/cvr/cvz163.
Levosimendan (LEVO) a clinically-used inodilator, exerts multifaceted cardioprotective effects. Case-studies indicate protection against doxorubicin (DXR)-induced cardiotoxicity, but this effect remains obscure. We investigated the effect and mechanism of different regimens of levosimendan on sub-chronic and chronic doxorubicin cardiotoxicity.
Based on preliminary in vivo experiments, rats serving as a sub-chronic model of doxorubicin-cardiotoxicity and were divided into: Control (N/S-0.9%), DXR (18 mg/kg-cumulative), DXR+LEVO (LEVO, 24 μg/kg-cumulative), and DXR+LEVO (acute) (LEVO, 24 μg/kg-bolus) for 14 days. Protein kinase-B (Akt), endothelial nitric oxide synthase (eNOS), and protein kinase-A and G (PKA/PKG) pathways emerged as contributors to the cardioprotection, converging onto phospholamban (PLN). To verify the contribution of PLN, phospholamban knockout (PLN-/-) mice were assigned to PLN-/-/Control (N/S-0.9%), PLN-/-/DXR (18 mg/kg), and PLN-/-/DXR+LEVO (ac) for 14 days. Furthermore, female breast cancer-bearing (BC) mice were divided into: Control (normal saline 0.9%, N/S 0.9%), DXR (18 mg/kg), LEVO, and DXR+LEVO (LEVO, 24 μg/kg-bolus) for 28 days. Echocardiography was performed in all protocols. To elucidate levosimendan's cardioprotective mechanism, primary cardiomyocytes were treated with doxorubicin or/and levosimendan and with N omega-nitro-L-arginine methyl ester (L-NAME), DT-2, and H-89 (eNOS, PKG, and PKA inhibitors, respectively); cardiomyocyte-toxicity was assessed. Single bolus administration of levosimendan abrogated DXR-induced cardiotoxicity and activated Akt/eNOS and cAMP-PKA/cGMP-PKG/PLN pathways but failed to exert cardioprotection in PLN-/- mice. Levosimendan's cardioprotection was also evident in the BC model. Finally, in vitro PKA inhibition abrogated levosimendan-mediated cardioprotection, indicating that its cardioprotection is cAMP-PKA dependent, while levosimendan preponderated over milrinone and dobutamine, by ameliorating calcium overload.
Single dose levosimendan prevented doxorubicin cardiotoxicity through a cAMP-PKA-PLN pathway, highlighting the role of inotropy in doxorubicin cardiotoxicity.
左西孟旦（LEVO）是一种临床应用的血管扩张剂，具有多方面的心脏保护作用。病例研究表明其可预防多柔比星（DXR）引起的心脏毒性，但这种作用仍不清楚。我们研究了不同方案的左西孟旦对亚慢性和慢性多柔比星心脏毒性的作用和机制。
基于初步的体内实验，多柔比星心脏毒性的亚慢性模型大鼠被分为：对照组（N/S-0.9%）、多柔比星组（18mg/kg-累积）、多柔比星+左西孟旦组（LEVO，24μg/kg-累积）和多柔比星+左西孟旦（急性）组（LEVO，24μg/kg-弹丸），共 14 天。蛋白激酶-B（Akt）、内皮型一氧化氮合酶（eNOS）和蛋白激酶-A 和 G（PKA/PKG）途径被认为是心脏保护作用的贡献者，它们都集中在磷酸化肌球蛋白轻链（PLN）上。为了验证 PLN 的作用，我们将磷酸化肌球蛋白轻链敲除（PLN-/-）小鼠分为 PLN-/-/对照组（N/S-0.9%）、PLN-/-/多柔比星组（18mg/kg）和 PLN-/-/多柔比星+左西孟旦（急性）组（LEVO，24μg/kg-弹丸），共 14 天。此外，雌性乳腺癌荷瘤（BC）小鼠被分为：对照组（生理盐水 0.9%，N/S 0.9%）、多柔比星组（18mg/kg）、左西孟旦组和多柔比星+左西孟旦组（LEVO，24μg/kg-弹丸），共 28 天。所有方案均进行超声心动图检查。为了阐明左西孟旦的心脏保护机制，我们用多柔比星和/或左西孟旦处理原代心肌细胞，并使用 Nω-硝基-L-精氨酸甲酯（L-NAME）、DT-2 和 H-89（分别为 eNOS、PKG 和 PKA 抑制剂）；评估心肌细胞毒性。单次给予左西孟旦可消除多柔比星引起的心脏毒性，并激活 Akt/eNOS 和 cAMP-PKA/cGMP-PKG/PLN 途径，但在 PLN-/-小鼠中未能发挥心脏保护作用。左西孟旦在 BC 模型中也表现出心脏保护作用。最后，体外 PKA 抑制消除了左西孟旦介导的心脏保护作用，表明其心脏保护作用依赖于 cAMP-PKA，而左西孟旦优于米力农和多巴酚丁胺，可改善钙超载。
单次剂量的左西孟旦通过 cAMP-PKA-PLN 途径预防多柔比星心脏毒性，突出了变力作用在多柔比星心脏毒性中的作用。
