Abstract 14648: Interleukin-18 Blockade Prevents Diastolic Dysfunction in a Mouse Model of Heart Failure With Preserved Ejection Fraction
Background: Heart failure with preserved ejection fraction (HFpEF) is characterized by elevated left ventricular (LV) filling pressures due to impaired LV diastolic function. Low-dose infusion of angiotensin 2 (AT2) in the mouse induces a HFpEF phenotype without increasing blood pressure. AT2 infusion induces expression of Interleukin-18 (IL-18) in the heart. We therefore tested whether IL-18 mediated AT2-induced LV diastolic dysfunction in this model.
Methods: We infused subcutaneously AT2 (0.2 mg/Kg/day) or a matching volume of vehicle via osmotic pumps surgically implanted in the interscapular space in adult wild-type (WT) male mice and IL-18 knock-out mice (IL-18KO). We also treated WT mice with daily intraperitoneal injections of recombinant murine IL-18 binding protein (IL-18bp, a naturally occurring IL-18 blocker) at 3 different doses (0.1, 0.3 and 1.0 mg/kg) or vehicle for 25 days starting on day 3. We performed a Doppler-echocardiography study before implantation and at 28 days to measure LV dimensions, mass, and systolic and diastolic function in all mice. LV catheterization was performed prior to sacrifice to measure LV end-diastolic pressure (LVEDP) using a Millar catheter.
Results: AT2 induces a significant increase in isovolumetric relaxation time (IRT) and myocardial performance index (MPI) at Doppler echocardiography and elevation of LVEDP at catheterization, indicative of impaired LV diastolic function, in absence of any measurable effects on systolic blood pressure nor LV dimensions, mass, or systolic function. Mice with genetic deletion of IL-18 (IL-18 KO) or WT mice treated with IL-18bp had no significant increase in IRT, MPI or LVEDP with AT2 infusion.
Conclusion: Genetic or pharmacologic IL-18 blockade prevent diastolic dysfunction in a mouse model of HFpEF induced by low dose AT2 infusion, suggesting a critical role of IL-18 in the pathophysiology of HFpEF.
- Heart Failure with Preserved Ejection Fraction
- Angiotensin II
- Diastolic Dysfunction
Author Disclosures: J.A. Regan: None. A.G. Mauro: None. S. Carbone: None. C. Marchetti: None. E. Mezzaroma: None. D. Krauskaus: None. F.N. Salloum: None. C.A. Dinarello: None. B. Van Tassel: None. A. Abbate: Research Grant; Significant; AB2 Bio. S. Toldo: None.
- © 2015 by American Heart Association, Inc.