Long-term functional and structural preservation of precision-cut human myocardium under continuous electromechanical stimulation in vitro

Abstract

In vitro models incorporating the complexity and function of adult human tissues are highly desired for translational research. Whilst vital slices of human myocardium approach these demands, their rapid degeneration in tissue culture precludes long-term experimentation. Here, we report preservation of structure and performance of human myocardium under conditions of physiological preload, compliance, and continuous excitation. In biomimetic culture, tissue slices prepared from explanted failing human hearts attain a stable state of contractility that can be monitored for up to 4 months or 2000000 beats in vitro. Cultured myocardium undergoes particular alterations in biomechanics, structure, and mRNA expression. The suitability of the model for drug safety evaluation is exemplified by repeated assessment of refractory period that permits sensitive analysis of repolarization impairment induced by the multimodal hERG-inhibitor pentamidine. Biomimetic tissue culture will provide new opportunities to study drug targets, gene functions, and cellular plasticity in adult human myocardium.

The Degree of t-System Remodeling Predicts Negative Force-Frequency Relationship and Prolonged Relaxation Time in Failing Human Myocardium

“…It is unknown if remodeling of the t-system, which commonly occurs in chronic heart failure, contributes to FFR inversion and slowing of contraction in intact myocardium from failing human hearts. Here, we describe a close correlation of t-system loss with negative FFR and altered contractile kinetics in human myocardial tissue slices, using confocal microscopy and a recently published method for biomimetic assessment and culture of human myocardium (Fischer et al, 2019). With this, we provide additional evidence that t-system remodeling is an important pathomechanism in heart failure and may predict myocardial dysfunction on a very small spatial scale.…”

“…Following a published method for stable cultivation of human myocardium (Fischer et al, 2019), myocardial slices of 300 µm thickness and approximately 5mm × 5mm length and width were cut with a high-precision vibratome (Leica VT1200S) and installed into biomimetic cultivation chambers at 37 • C. Electrodes and a force-transducing wire included in the chambers allowed for continuous electrical stimulation and monitoring of contractile force during auxotonic (elastic) contraction (see Supplementary Figure S1). The sarcomere length at different degrees of preload was assessed in initial experiments by α-actinin staining.…”

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

“…Additionally, multiple slices can be prepared from a single specimen allowing for high-throughput experimentation. We and others have shown that slices can be kept in in vitro culture for prolonged periods of time with minimal loss of the adult myocardial phenotype (Kang et al, 2016;Fischer et al, 2019;Watson et al, 2019). As such, myocardial slices are uniquely positioned for interrogation of effects of chronic load on the myocardium away from the confounding influences of the neurohormonal arm.…”

SARS-CoV-2 infects and induces cytotoxic effects in human cardiomyocytes

“…Finally, we addressed whether SARS-CoV-2 infects human heart tissue by using living human cardiac tissue slices, which were obtained from explanted hearts 16 (Figure 4a-f). Here, increased spike protein expression was shown in four different samples derived from three donors (Figure 4c-e).…”