A practical guide for investigating cardiac physiology using living myocardial slices

Figures

• 

  Fig. 1. Living myocardial slices within the cardiac research pipeline. LMS can be prepared from heart samples, including whole heart animal models and human myectomy or LVAD samples. Interrogation of cardiac function, structure and biochemistry can then be performed on LMS. It is also possible to isolate individual cardiac cell populations from LMS. All of the data obtained can then be integrated with human/in vivo data the LMS are derived from

• 

  Fig. 2. Interrogation of LMS function, structure and biochemistry. Several assays can be used to interrogate the function, structure and biochemistry of myocardial slices. Functional assessment includes contractile function, conduction velocity, Ca2+ handling, action potential, metabolomics and viability. Structural assessment can be conducted using traditional sectioning and staining methods. Additionally, immunohistochemical staining and microscopy can easily be performed and optical clearing protocols have been developed for whole slice imaging. Biochemistry assays can be conducted at the genomic, proteomic and secretomic levels. Longitudinal functional assessment of LMS can also be performed during chronic culture. The RNA sequencing image in this figure was previously published [43]

• 

  Fig. 3. Imaging LMS. a Imaging of LMS is best conducted when LMS are flat, allowing acquisition of images of cells within a single plane. During fixation, cardiomyocyte hypercontraction can result in tissue deformation and folding, which makes image acquisition time consuming and technically challenging. This can be overcome by performing fixation with the LMS mechanically stretched and imaging performed, while the slice is flattened with a glass coverslip. b Representative vimentin staining of rat LMS. c Cross section of LMS stained for WGA (in red) and DAPI (in green). d LMS stained for isolectin-B4 (in green) and DAPI (in red) to identify endothelial cells and cardiac cell nuclei

• 

  Fig. 4. Isolating cells from LMS. LMS can be broken down into constituent cell populations, including isolation of cardiomyocytes, fibroblasts, endothelial cells, inflammatory cells or any other cardiac cell type