Influence of Supraphysiologic Biomaterial Stiffness on Ventricular Mechanics and Infarct Reinforcement

Injectable intramyocardial biomaterials have promise to limit adverse ventricular remodeling through me-chanical and biologic mechanisms. While some success has been observed by injecting materials to re-generate new tissue, optimal biomaterial stiffness to thicken and stiffen infarcted myocardium to limit adverse remodeling has not been determined. In this work, we present an in-vivo study of the impact of biomaterial stiffness over a wide range of stiffness moduli on ventricular mechanics. We utilized in-jectable methacrylated polyethylene glycol (PEG) hydrogels fabricated at 3 different mechanical moduli: 5 kPa (low), 25 kPa (medium/myocardium), and 250 kPa (high/supraphysiologic). We demonstrate that the supraphysiological high stiffness favorably alters post-infarct ventricular mechanics and prevents neg-ative tissue remodeling. Lower stiffness materials do not alter mechanics and thus to be effective, must instead target biological reparative mechanisms. These results may influence rationale design criteria for biomaterials developed for infarct reinforcement therapy.Statement of significanceAcellular biomaterials for cardiac application can provide benefit via mechanical and biological mecha-nisms post myocardial infarction. We study the role of biomaterial mechanical characteristics on ven-tricular mechanics in myocardial infarcts. Previous studies have not measured the influence of injected biomaterials on ventricular mechanics, and consequently rational design criteria is unknown. By utilizing an in-vivo assessment of ventricular mechanics, we demonstrate that low stiffness biomaterial do not alter pathologic ventricular mechanics. Thus, to be effective, low stiffness biomaterials must target bio-logical reparative mechanisms. Physiologic and supra-physiologic biomaterials favorably alter post-infarct mechanics and prevents adverse ventricular remodeling. (c) 2022 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Automated summary

Injectable intramyocardial biomaterials have the potential to limit adverse ventricular remodeling through mechanical and biologic mechanisms. This study investigates the impact of biomaterial stiffness on ventricular mechanics in myocardial infarcts and demonstrates that high stiffness biomaterials can improve post-infarct ventricular mechanics and prevent negative tissue remodeling.