Thliveris, James A.

Background/Objectives: While doxorubicin (DOX) and trastuzumab (TRZ) improve overall survival in women with breast cancer, these two anti-cancer drugs increase the risk of developing heart failure. As a novel and largely unexplored approach, our aim was to evaluate whether the prophylactic use of the sodium-glucose co-transporter 2 inhibitor empagliflozin (EMPA), with and without the angiotensin converting enzyme inhibitor perindopril (PER), is cardioprotective in preventing DOX + TRZ-mediated cardiotoxicity. Methods: In a chronic in vivo murine model, female mice received prophylactic treatment with PER (3 mg/kg), EMPA (10 mg/kg), or EMPA + PER via oral gavage for a total of 3 weeks as a run-in period prior to weekly administration of DOX + TRZ (8 mg/kg and 3 mg/kg, respectively) intraperitoneally for an additional 3 weeks (total of 6 weeks). Results: In mice treated with DOX + TRZ, the left ventricular ejection fraction (LVEF) decreased from 75 ± 2% at baseline to 40 ± 4% at week 6. Prophylactic treatment with either PER, EMPA, or EMPA+PER improved LVEF to 58 ± 3%, 66 ± 3%, and 67 ± 4% at week 6, respectively (p < 0.05). Histological analyses confirmed significant disruption of myofibrils, vacuolization, and loss of sarcomere integrity in the DOX + TRZ-treated mice. Prophylactic administration with PER, EMPA, or EMPA + PER, however, improved myofibril integrity at week 6 in mice receiving DOX + TRZ. Finally, although the Bax/Bcl-xL ratio was significantly elevated by 1.5-fold in mice treated with DOX + TRZ, this marker of apoptosis was attenuated by prophylactic treatment with either PER, EMPA, or EMPA + PER. Conclusions: Prophylactic administration of EMPA mitigated adverse cardiovascular remodeling in a chronic in vivo model of DOX + TRZ-mediated cardiotoxicity.

The recent introduction of novel anticancer therapies, including bevacizumab (BVZ) and sunitinib (SNT), is associated with an increased risk of cardiotoxicity. However, early identification of left ventricular (LV) systolic dysfunction may facilitate dose modification and avoid the development of advanced heart failure. Using a murine model of BVZ- and SNT-mediated cardiotoxicity, we investigated whether cardiac biomarkers and/or tissue velocity imaging (TVI) using echocardiography can detect early changes in cardiac function, before a decrease in LV ejection fraction is identified. A total of 75 wild-type C57Bl/6 male mice were treated with either 0.9% saline, BVZ, or SNT. Serial monitoring of blood pressure, high-sensitivity troponin I, and echocardiographic indexes were performed over a 14-day study period, after which the mice were euthanized for histological and biochemical analyses. Mice treated with either BVZ or SNT developed systemic hypertension as early as day 7, which increased by day 14. Cardiac biomarkers, specifically high-sensitivity troponin I, were not predictive of early LV systolic dysfunction. Although conventional LV ejection fraction values decreased at day 13 in mice treated with either BVZ or SNT, TVI confirmed early LV systolic dysfunction at day 8. Histological and biochemical analysis demonstrated loss of cellular integrity, increased oxidative stress, and increased cardiac apoptosis in mice treated with BVZ or SNT therapy at day 14. In a murine model of BVZ- or SNT-mediated cardiomyopathy, noninvasive assessment by TVI detected early LV systolic dysfunction before alterations in conventional echocardiographic indexes.