Abstract 15130: Biophysical Effects of a Hyaluronic Acid Based Hydrogel on Average Peak Stress of the Left Ventricular Wall Post Myocardial Infarction
Background: : A common event following a myocardial infarction (MI) is left ventricular (LV) remodeling characterized by mural wall thinning of the MI region and LV dilation, resulting in increased peak wall stress. Past studies have demonstrated that targeted injection of biomaterials within the MI region, such as hydrogels (gels), can alter this process. However, the temporal relationship between these LV remodeling events to gel biophysical effects remained unknown, and therefore formed the purpose of this study.
Methods/Results: MI was induced in pigs (25 kg; coronary ligation) and randomized to targeted injections of a hyaluronic acid (HA) based hydrogel (MI/gel, n=3; 4% HA polymer modified with hydroxyethyl methacrylate, crosslinked through redox reaction, 9-100uL injections), or saline (MI only; n=9), whereby MI thickness and LV peak stress (radial-circumferential) were determined by echocardiography at 1-14 days post-MI. Concurrently, the HA based gels were injected into an in-vitro mold simulating the in-vivo injection, immersed in saline (37°), and the compressive modulus determined (uniaxial compression) at identical post-MI time points in order to quantify the transient changes in biophysical properties in-vitro. MI thinning and LV peak wall stress increased as a function of time post-MI in both groups but were attenuated in the MI/gel group post-MI (Figure-left). Isochronal plots of LV wall stress and gel compressive modulus were inversely related and stress demonstrated a significant (p<0.05) increase following the cross over at the time where the gel modulus dissipated (Figure-right).
Conclusion: This study presents a biophysical mechanism by which injectable hydrogels alter the post-MI remodeling process. These findings suggest that matched in-vivo and in-vitro biophysical measurements can be utilized to optimize hydrogel formulations that alter the post-MI remodeling process and thus hold therapeutic relevance.
- © 2013 by American Heart Association, Inc.