C49 SACUBITRIL–VALSARTAN IMPROVES LONGITUDINAL STRAIN AND EJECTION FRACTION IN MICE TREATED WITH DOXORUBICIN THROUGH NLRP3, MYD88 PATHWAYS RESULTING IN A REDUCTION OF MYOCARDIAL IL–1Β, IL–6, TNF–Α, G–CSF AND GM–CSF LEVELS

Abstract

Abstract Introduction Doxorubicin–mediated adverse cardiovascular events are among the leading causes of morbidity and mortality in breast cancer patients. Sacubitril–valsartan (LCZ 696) is a combination drug, made up of neprilysin inhibitor sacubitril and angiotensin II receptor blocker valsartan, used for the treatment of heart failure in patients with a reduced ejection fraction. Purpose We hypothesized that LCZ 696, administered during doxorubicin, could improve cardiac function and cardiac inflammation in preclinical models Methods Human fetal cardiomyocytes (HFC cell line) were exposed to subclinical concentration of doxorubicin (200 nM) alone or in combination with LCZ–696 (100 mM) for 72 h. After the incubation period, we performed the following tests: cell viability, apoptosis and necrosis; expression of malondialdehyde and 4–hydroxynonenal and concentration of intracellular Ca2+. Moreover, pro–inflammatory studied were also performed (activation of NLRP3 inflammasome; expression of TLR4/MyD88; mTORC1 Fox01/3a; NF–κB). C57Bl/6 mice were untreated (Sham, n = 6) or treated for 10 days with doxorubicin i.p at 2.17 mg/kg (DOXO, n = 6), LCZ–696 at 60 mg/kg (LCZ, n = 6) or doxorubicin combined to LCZ–696 (DOXO–LCZ, n = 6). Ejection fraction, radial and longitudinal strain were analyzed through transthoracic echocardiography (Vevo 2100). Cardiac tissue expression of NLRP3 inflammasome, Myd88, NF–kB and 13 chemokines (IL–1α, IL–1β, IL–2, IL–4, IL–6, IL–10, IL–12, IL17–α, IL–18, IFN–γ, TNF–α, G–CSF, and GM–CSF) were quantified. Results LCZ–696 exerts cardioprotective effects, enhancing cell viability of 48–54.6% compared to only doxorubicin–treated cells (p < 0,001 for all); LCZ 696 decreased NLRP3, MyD88 and NF–kB expression in cardiac cells. In preclinical study, LCZ 696 improved significantly the EF and prevented the reduction of radial and longitudinal strain after 10 days of treatment with doxorubicin. A reduced expression of NLRP3, MyD88 and NF–kB in cardiac tissues was seen in DOXO–LCZ group compared to DOXO mice (p < 0.001). Cardiac expression of IL–1β, IL–6, TNF–α, G–CSF and GM–CSF were significantly reduced after treatment with LCZ–696 indicating anti–inflammatory properties. Conclusion LCZ–696 exerts direct beneficial effects in cardiomyocytes exposed to doxorubicin. In preclinical models, LCZ–696 reduced inflammation and cytokine expression involved in doxorubicin–mediated cardiotoxicity.