CARDIAC MACROPHAGES EXACERBATE DOXORUBICIN-INDUCED CARDIOTOXICITY

Abstract

Objective: The functional contribution of non-myocyte cardiac cells, such as inflammatory cells, in the setup of heart failure in response to doxorubicin (Dox) is recently becoming of growing interest. Objective: The study aims to evaluate the role of macrophages in cardiac damage elicited by Dox treatment. Design and method: C57BL/6 mice were treated with one intraperitoneal injection of Dox (20mg/Kg) and followed up for 5 days by cardiac ultrasounds (CUS), histological, and flow cytometry evaluations. We also tested the impact of Dox in macrophage-depleted mice. Murine cardiomyoblasts were directly treated with Dox (D-Dox) or with a conditioned medium from cultured murine macrophages treated with Dox (M-Dox). Results: In response to Dox, macrophage infiltration preceded cardiac damage. Macrophage depletion prevents Dox-induced damage, suggesting a key role of these cells in promoting cardiotoxicity. To evaluate the crosstalk between macrophages and cardiac cells in response to DOX, we compared the effects of D-Dox and M-Dox in vitro. In cardiomyoblasts, cell vitality was lower and apoptosis was higher in response to M-Dox compared with D-Dox. These events were linked to p53-induced alterations of mitochondria morphology, function, and autophagy. We identify a mechanistic role of catecholamines released by Dox-activated macrophages that lead to mitochondrial apoptosis of cardiac cells through b-AR stimulation. Conclusions: Taken together, our data indicate that crosstalk between macrophages and cardiac cells participates in cardiac damage in response to Dox.