Repeated Remote Ischemic Conditioning Reduces Doxorubicin-Induced Cardiotoxicity

OBJECTIVES This study investigated the cardioprotective effect of repeated remote ischemic preconditioning (rRIC) on doxorubicin-induced cardiotoxicity in mice. BACKGROUND Doxorubicin is an effective chemotherapeutic agent for a wide range of tumor types but its use and dosing are limited by acute and chronic cardiotoxicity. Remote ischemic conditioning (RIC) is cardioprotective in multiple cardiovascular injury models, but the effectiveness of rRIC in doxorubicin-induced cardiotoxicity has not been fully elucidated. METHODS rRIC was performed on mice before and after doxorubicin administration. Cardiac function was assessed by echocardiography and myocardial biology was tested by molecular approaches. RESULTS Doxorubicin administration induced acute cardiotoxicity, as indicated by reduced cardiac function, reduced myocyte cross-section area and increased extracellular collagen deposition, increased circulating cardiac muscle damage markers, and decreased heart weight. Doxorubicin also adversely affected other organs, including the kidney, liver, and spleen, as evaluated by circulating markers or organ weight loss. rRIC not only abrogated doxorubicin-induced cardio- toxicity (left ventricular ejection fraction, doxorubicin 47.5 ? 1.1%, doxorubicin þ rRIC 51.6 ? 0.7%, p ¼ 0.017), but also was associated with multiorgan protection. Within the myocardium, rRIC attenuated doxorubicin-induced cardiomyocyte apoptosis, reduced inflammation, and increased autophagy signaling. CONCLUSIONS rRIC may be a promising approach to reduce doxorubicin-induced cardiotoxicity. (J Am Coll Cardiol CardioOnc 2020;2:41–52) © 2020 The Authors. Published by Elsevier on behalf of the American College of Cardiology Foundation.