Abstract 3328: Mitigating long-term cardiac adverse effects of radiation exposure: Emerging opportunities in protein oxidation and autophagy modulation

Abstract

Abstract Radiation-induced heart disease (RIHD) presents a significant challenge in the oncology setting. Patients who receive acute doses of irradiation to the thoracic cavity for Hodgkin's Lymphoma and breast cancer are subject to an elevated risk of RIHD. The ability to mitigate the long-term cardiac effects of radiation exposure in these populations by modulating protein oxidation and the process of autophagy in the heart has the potential to lead to improved health outcomes. We utilized the spontaneously hypertensive rat (SHR), which has proven a good model for drug-induced cardiotoxicity, to evaluate radiation-induced heart disease. SHRs were exposed to low, medium, or high doses of full-body irradiation. Necropsy was performed to collect serum and tissue samples at various time points up to one year. Echocardiography and electrocardiography were performed to evaluate functional changes in cardiac performance. Four weeks following ionizing radiation, both males and females showed decreased heart mass and decreased whole body mass in the groups exposed to medium and high doses of radiation. A marked difference in both heart and whole body mass was observed in the high dose group after one year. Anemic conditions were noted by low red blood cell counts observed in both males and females at all three time points in the animals receiving the highest dose of irradiation. Cardiac troponin T analysis revealed cardiotoxicity in both the medium and high dose groups at early time points. Echocardiography revealed that left ventricular volume at diastole was increased in males following high dose irradiation, and that left ventricular mass decreased following high irradiation exposures. Finally, it should also be noted that after one year, multiple animals receiving radiation developed spontaneous tumors. We are currently exploring the oxidative stress-mediated molecular mechanisms behind the radiation-induced cardiac damage and the subsequent, protective autophagic response. Citation Format: Elliot T. Rosen, Dmitry Kryndushkin, Yanira Gonzalez, Baikuntha Aryal, Leena Chehab, Jennifer Dickey, Ashutosh Rao. Mitigating long-term cardiac adverse effects of radiation exposure: Emerging opportunities in protein oxidation and autophagy modulation. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3328. doi:10.1158/1538-7445.AM2015-3328