Abstract 14880: Interleukin-18 in Radiation-induced Cardiomyopathy

Introduction: Thoracic radiation (XRT) used in treatment of cancer leads to the development of cardiomyopathy, characterized by increased myocardial and pericardial fibrosis. A close link between XRT injury, fibrosis and inflammation exists. Interleukin-18, a proinflammatory cytokines of the IL-1 family, has been shown to promote cardiac fibrosis. Hypothesis: IL-18 mediates myocardial and pericardial fibrosis following thoracic XRT. Methods: We exposed C57BL/6J female mice (N=6-12/group) to XRT 20 Gray (Gy). Echocardiography was performed to assess left ventricular (LV) ejection fraction (EF) at baseline, and 3 days and 4 months following XRT. LV catheterization was used to measure the LV end diastolic pressure (EDP), LV peak systolic pressure, +dP/dt and -dP/dt. Masson’s Trichrome was used to quantify interstitial fibrosis and pericardial thickening. Western Blot (WB) and Immunofluorescence (IF) were used to measure IL-18 levels in the heart after XRT. Sham-XRT mice were used as controls. Results: Thorac...