Heart Scar-In-A-Dish: Tissue Culture Platform to Study Myocardial Infarct Healing In Vitro

MJ Potter, JD Heywood, SJ Coeyman, WJ Richardson

Posted on: 28 April 2025 , updated on: 29 April 2025

Preprint posted on 2 March 2025

In this preprint, the authors employ a cryoinjury model to produce a three-dimensional (3D) Myocardial Infarction (MI)-Engineered Heart Tissue (EHT) platform that spatially/temporally mimics the evolution of MI.

Selected by Theodora Stougiannou

Categories: bioengineering, cell biology

Engineering a Broken Heart

Background:

There are many different ways to model cardiac tissue in vitro: from self-assembling organoids that mimic stages of cardiac development (Cardiac organoid) to externally assembled cardiac tissues that can be produced with (Cardiac microtissue) or without use of extracellular matrix material such as hydrogel (Engineered heart tissue [EHT]) [1]. Often, these constructs can be additionally modified to resemble pathological tissue with localized cell death (necrosis/apoptosis), activation of specialized cell populations (myofibroblasts) and deposition/turnover of extracellular material.

Myocardial infarction (MI) results from obstruction of blood flow to a tissue area, activating signaling cascades associated with tissue hypoxia and cellular death and causing tissue injury (infarct). In general, MI comprises a central ischemic zone (IZ), a border zone (BZ) surrounding the central ischemic core and a peripheral zone which corresponds to healthy myocardium. In vivo, various methods can be used to recreate MI tissue injury, including permanent ligation (PL), where a coronary artery is permanently obstructed, ischemia-reperfusion (I/R) where the occlusion in question is temporary [2] and cryoinjury [3]. In vitro, methods used include I/R (modulation of oxygen levels) [4], cryoinjury [3], metabolic inhibition (cyanide) and recapitulation of anaerobic glycolysis conditions [5].

In this preprint, the authors employed a cryoinjury MI model to produce a three-dimensional (3D) MI-EHT platform that mimics the evolution of MI spatially/temporally. Three zones were observed in the constructs: a central wound zone (W), a border zone (B) and a remote zone (R), with overall progression characterized across Days 1, 3 and 7 post-injury [6].

Key characteristics of the MI-EHT platform:

Effects on cell viability: Cardiomyocyte and cardiac fibroblast viability were reduced in all areas of the EHT, including the remote areas where cellular death is not normally observed, with cardiac fibroblast populations recovering by Day 7 in zones B and R and cardiomyocytes continuously dropping [6].
Effects on stiffness: The authors measured Modulus values in the three EHT locations (W, B, R) as time unfolded after injury and observed the greatest increases on Day 7 in zone W, with a value reaching up to ~ 100 Pa (N/m²). The central ischemic core (W) thus exhibited much higher stiffness compared to the surrounding zones. In addition, there were differences in values between regions, something not seen in control EHT [6].
Effects on systolic strain: While control EHT tissues exhibited contractile strains, with highest values in the center, MI-EHT exhibited heterogenous strains across different regions. Strains in central locations (W, B) further shifted from contractile (control EHT) to tensile, with statistically significant increases noted on Day 7. Systolic strains tended to increase with increasing days in culture [6].

Definition of terms used in the study:

Stiffness (K) is a mechanical property of materials as well as living tissues, defined as the degree to which tissue resists deformation after mechanical force is applied, and depending on tissue composition. It depends on both the geometric structure and material/tissue composition [7].
The Elastic modulus (E) provides an indication of the tendency of materials to resist elastic deformation; stiff materials/tissues require increased loads to bring about elastic deformation, while flexible materials require lower loads to bring about elastic deformation and as a result, a change in shape [7].
Myocardial strain (%) is used to describe the total deformation of ventricular myocardial tissue occurring during one cardiac cycle; myocardial deformation can be circumferential, radial and longitudinal [8].
Systolic strain (%) is defined as the change in myofibrillar length towards multiple directions, as the left ventricle contracts; it is calculated at the end of ventricular systole, as the aortic valve closes [8]. In this study, the authors measured strains occurring in the three EHT zones between systolic contraction and diastolic relaxation [6].

Why this work is interesting:

The MI-EHT constructs created as part of this study represent a heterogenous 3D environment with variations in cell survival and mechanical characteristics, essentially an MI platform. While this study focuses on mechanical aspects of injured tissue [6], the constructs represent an exciting chance to produce 3D recreations of injured/surrounding tissues, which can be modified to be patient-specific (provided the cellular components are derived from patient-specific induced pluripotent stem cells [iPSC]). They can also be used as a drug-testing platform, which may also be adapted for patient-specific uses.

Questions I would like to ask the authors about their work:

What prompted you to use the cryoinjury model to recreate MI in the EHT, as opposed to other MI injury models? What advantages do you think utilization of this injury method has brought with regard to the recapitulation of the injury observed in vivo, compared to other MI injury methods, if any?
Do you think this platform could be adapted to evaluate electric signal propagation in infarcted tissue and, as a result, model arrhythmias associated with MI [9]?

References:

[1] Drakhlis L, Zweigerdt R. Heart in a dish – choosing the right in vitro model. Disease Models & Mechanisms 2023;16:dmm049961. https://doi.org/10.1242/dmm.049961.

[2] De Villiers C, Riley PR. Mouse models of myocardial infarction: comparing permanent ligation and ischaemia-reperfusion. Dis Model Mech 2020;13:dmm046565. https://doi.org/10.1242/dmm.046565.

[3] Voges HK, Mills RJ, Elliott DA, Parton RG, Porrello ER, Hudson JE. Development of a human cardiac organoid injury model reveals innate regenerative potential. Development 2017;144:1118–27. https://doi.org/10.1242/dev.143966.

[4] Sharma P, Liu Chung Ming C, Gentile C. In vitro modeling of myocardial ischemia/reperfusion injury with murine or human 3D cardiac spheroids. STAR Protocols 2022;3:101751. https://doi.org/10.1016/j.xpro.2022.101751.

[5] Chen T, Vunjak-Novakovic G. In vitro Models of Ischemia-Reperfusion Injury. Regen Eng Transl Med 2018;4:142–53. https://doi.org/10.1007/s40883-018-0056-0.

[6] Potter MJ, Heywood JD, Coeyman SJ, Richardson WJ. Heart Scar-In-A-Dish: Tissue Culture Platform to Study Myocardial Infarct Healing In Vitro 2025:2025.02.28.640625. https://doi.org/10.1101/2025.02.28.640625.

[7] Villa C, Chaplain MAJ, Gerisch A, Lorenzi T. Mechanical Models of Pattern and Form in Biological Tissues: The Role of Stress–Strain Constitutive Equations. Bull Math Biol 2021;83:80. https://doi.org/10.1007/s11538-021-00912-5.

[8] Brady B, King G, Murphy RT, Walsh D. Myocardial strain: a clinical review. Ir J Med Sci 2022:1–8. https://doi.org/10.1007/s11845-022-03210-8.

[9] Nguyen TP, Qu Z, Weiss JN. Cardiac Fibrosis and Arrhythmogenesis: The Road to Repair is Paved with Perils. J Mol Cell Cardiol 2014;0:83–91. https://doi.org/10.1016/j.yjmcc.2013.10.018.

Tags: engineering, heart, infarction, myocardial, tissue

doi: https://doi.org/10.1242/prelights.40301

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