Effect of biomaterial stiffness on cardiac mechanics in a biventricular infarcted rat heart model with microstructural representation of in situ intramyocardial injectate

Y D Motchon; Kevin L Sack; M S Sirry; M Kruger; E Pauwels; D Van Loo; A De Muynck; L Van Hoorebeke; Neil H Davies; Thomas Franz

doi:10.1002/cnm.3693

Effect of biomaterial stiffness on cardiac mechanics in a biventricular infarcted rat heart model with microstructural representation of in situ intramyocardial injectate

Int J Numer Method Biomed Eng. 2023 May;39(5):e3693. doi: 10.1002/cnm.3693. Epub 2023 Mar 2.

Authors

Y D Motchon¹, Kevin L Sack^{1

2}, M S Sirry³, M Kruger⁴, E Pauwels^{5

6}, D Van Loo^{5

7}, A De Muynck⁵, L Van Hoorebeke⁵, Neil H Davies⁴, Thomas Franz^{1

8}

Affiliations

¹ Biomedical Engineering Research Centre, Division of Biomedical Engineering, Department of Human Biology, University of Cape Town, Cape Town, South Africa.
² Department of Surgery, University of California at San Francisco, San Francisco, California, USA.
³ Department of Biomedical Engineering, School of Engineering and Computing, American International University, Al Jahra, Kuwait.
⁴ Cardiovascular Research Unit, MRC IUCHRU, University of Cape Town, Cape Town, South Africa.
⁵ Centre for X-ray Tomography, Department of Physics and Astronomy, Ghent University, Ghent, Belgium.
⁶ Nuclear Medicine, University Hospitals Leuven, Leuven, Belgium.
⁷ XRE nv, Bollebergen 2B box 1, 9052, Ghent, Belgium.
⁸ Bioengineering Science Research Group, Faculty of Engineering and Physical Sciences, University of Southampton, Southampton, UK.

Abstract

Intramyocardial 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 an in situ biomaterial 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 1 week after infarct induction was developed from ex vivo microcomputed tomography data. The volumetric mesh density varied between 303 mm^-3 in the myocardium and 3852 mm^-3 in 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 and in silico studies of mechanotransduction and therapeutic signalling in the infarcted heart with an infarct animal model extensively used in preclinical research.

Keywords: biomaterial injection therapy; cardiac mechanics; finite element method; myocardial infarction.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Animals
Biocompatible Materials
Heart Ventricles
Mechanotransduction, Cellular*
Myocardial Infarction*
Myocardium
Myocytes, Cardiac
Rats
X-Ray Microtomography

Substances

Biocompatible Materials