Abstract
AbstractIntramyocardial delivery of biomaterials is a promising concept for treating myocardial infarction. The delivered biomaterial provides mechanical support and attenuates wall thinning and elevated wall stress in the infarct region. This study aimed at developing a biventricular finite element model of an infarcted rat heart with a microstructural representation of anin situbiomaterial injectate, and a parametric investigation of the effect of the injectate stiffness on the cardiac mechanics.A three-dimensional subject-specific biventricular finite element model of a rat heart with left ventricular infarct and microstructurally dispersed biomaterial delivered one week after infarct induction was developed fromex vivomicrocomputed tomography data. The volumetric mesh density varied between 303 mm-3in the myocardium and 3,852 mm-3in the injectate region due to the microstructural intramyocardial dispersion. Parametric simulations were conducted with the injectate’s elastic modulus varying from 4.1 to 405,900 kPa, and myocardial and injectate strains were recorded.With increasing injectate stiffness, the end-diastolic median myocardial fibre and cross-fibre strain decreased in magnitude from 3.6% to 1.1% and from −6.0% to −2.9%, respectively. At end-systole, the myocardial fibre and cross-fibre strain decreased in magnitude from −20.4% to −11.8% and from 6.5% to 4.6%, respectively. In the injectate, the maximum and minimum principal strains decreased in magnitude from 5.4% to 0.001% and from −5.4% to −0.001%, respectively, at end-diastole and from 38.5% to 0.06% and from −39.0% to −0.06%, respectively, at end-systole.With the microstructural injectate geometry, the developed subject-specific cardiac finite element model offers potential for extension to cellular injectates andin silicostudies of mechanotransduction and therapeutic signalling in the infarcted heart with an infarct animal model extensively used in preclinical research.
Publisher
Cold Spring Harbor Laboratory