Preparation of viable adult ventricular myocardial slices from large and small mammals

Abstract

This protocol describes the preparation of highly viable adult ventricular myocardial slices from the hearts of small and large mammals, including rodents, pigs, dogs and humans. Adult ventricular myocardial slices are 100- to 400-μm-thick slices of living myocardium that retain the native multicellularity, architecture and physiology of the heart. This protocol provides a list of the equipment and reagents required alongside a detailed description of the methodology for heart explantation, tissue preparation, slicing with a vibratome and handling of myocardial slices. Supplementary videos are included to visually demonstrate these steps. A number of critical steps are addressed that must be followed in order to prepare highly viable myocardial slices. These include identification of myocardial fiber direction and fiber alignment within the tissue block, careful temperature control, use of an excitation-contraction uncoupler, optimal vibratome settings and correct handling of myocardial slices. Many aspects of cardiac structure and function can be studied using myocardial slices in vitro. Typical results obtained with hearts from a small mammal (rat) and a large mammal (human) with heart failure are shown, demonstrating myocardial slice viability, maximum contractility, Ca handling and structure. This protocol can be completed in ∼4 h.

Epicardial slices: a 3D organotypic model for the study of epicardial activation and differentiation

“…Epicardial slices maintain normal heart tissue architecture, as demonstrated by the preservation of functional markers and architecture in the myocardial portion of the slice, comparable with previous reports in myocardial slices (19,29,30). More importantly, slices present an intact epicardial monolayer expressing typical markers such as MSLN, E-cadherin and WT1.…”

Heart Plasticity in Response to Pressure- and Volume-Overload: A Review of Findings in Compensated and Decompensated Phenotypes

“…Although each cardiac model has unique advantages and limitations, many contemporary in vitro assays are oversimplified, and/or have low experimental throughput (Pitoulis F. G. et al, 2019). For example, isolated cardiomyocytes lack extracellular matrix (Watson et al, 2017). The relevance of engineered heart tissue (EHT) constructs to adult myocardium needs to be validated (Dhahri et al, 2018), and papillary muscles, whole hearts, and trabecula may suffer from low experimental throughput (Schechter et al, 2014).…”

“…In our lab we have pioneered the development of a novel in vitro cardiac model known as myocardial slices (Perbellini et al, 2017;Watson et al, 2017Watson et al, , 2019. Myocardial slices are living organotypic preparations that can be prepared from mammalian hearts including human biopsies (Watson et al, 2017). The nature of the preparation means that myocardial functional (contractility, electrophysiology) and structural properties (ECM, heteroand multi-cellularity) of the original tissue are preserved.…”

Physiological Biomimetic Culture System for Pig and Human Heart Slices

“…In this study, we used 3 de-identified human hearts from donors aged 36, 42, and 45 years old with no cardiovascular disease history. As described before in 11,15 , pig or human hearts were clamped at the aortic arch and perfused with 1 L sterile cardioplegia solution (110 mM NaCl, 1.2 mM CaCl 2 , 16 mM KCl, 16 mM MgCl 2 , 10 mM NaHCO 3 , 5 units/ml heparin, pH to 7.4), then the hearts were preserved on ice-cold cardioplegic solution until transported to the lab on wet ice within 12 hours.…”

“…Even though the electrophysiological properties of the heart slices were maintained for 28 days, the heart slices lost over 90% of their ability to contract within 24 hours in culture 9 . This culture system has been used by others to culture heart slices for up to 24 hours [10][11][12] . Three recent studies have shown that electromechanical stimulation is paramount for maintaining heart slices in culture [13][14][15] .…”