Abstract 16714: An Injectable Thermo-Responsive Hydrogel as a Tool for Cardiac Tissue Engineering Efforts: In vitro and in vivo Biocompatibility Assessment

Abstract

Background: Heart failure (HF) is a major contributor to the global burden of cardiovascular disease. Current treatments for HF do not regenerate muscle nor function and so cardiac transplantation remains the only definitive treatment for HF. Thus, novel therapies for HF are still needed. To overcome this limitation, we engineered an injectable thermo-responsive hydrogel that transitions from a liquid-solution to a gel-based matrix upon reaching body temperature allowing for a liquid injection rapidly followed by gel localization. Previously, we demonstrated the potential of our hydrogel for cardiac tissue applications using primary cardiomyocytes. Goal: The goal of this project is to assess the biocompatibility of the thermo-responsive hydrogel with human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CM) and its effect on mice heart tissue. Methods: 3D cell culture: 9x104 hiPSC-CM were encapsulated for 21 days using 150μl of hydrogel solution (1.5% w/w) and cell function was assessed afterwards. Mouse intracardial injection: a left thoracotomy was performed via the fourth intercostal space in an adult C57BL/6 mouse model. Then, three injections of 10 μl of either (i) lipofectamine, (ii) hydrogel (1% w/w) or (ii) saline were injected into the left ventricle anterior wall. After injections, the thoracotomy site was closed, and the animals recovered. Four weeks post inject the tissues were harvested and prepared for studies. Results: We found that our hydrogel promotes hiPSC-CMs alignment, elongation with increased Cx43 localization and improved contraction function when compared with traditional 2D fibronectin controls. Furthermore, the in-vivo biocompatibility in mice (intracardial injection) proved that our hydrogel is well tolerated by cardiac tissue. Conclusion: Our results indicated that the injectable thermos-responsive hydrogel is a biocompatible material with potential to be used in cardiac tissue engineering efforts.