Biomimetic electromechanical stimulation to maintain adult myocardial slices in vitro

Abstract

Adult cardiac tissue undergoes a rapid process of dedifferentiation when cultured outside the body. The in vivo environment, particularly constant electromechanical stimulation, is fundamental to the regulation of cardiac structure and function. We investigated the role of electromechanical stimulation in preventing culture-induced dedifferentiation of adult cardiac tissue using rat, rabbit and human heart failure myocardial slices. Here we report that the application of a preload equivalent to sarcomere length (SL) = 2.2 μm is optimal for the maintenance of rat myocardial slice structural, functional and transcriptional properties at 24 h. Gene sets associated with the preservation of structure and function are activated, while gene sets involved in dedifferentiation are suppressed. The maximum contractility of human heart failure myocardial slices at 24 h is also optimally maintained at SL = 2.2 μm. Rabbit myocardial slices cultured at SL = 2.2 μm remain stable for 5 days. This approach substantially prolongs the culture of adult cardiac tissue in vitro.

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

“…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).…”

“…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.…”

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

“…The sarcomere length at different degrees of preload was assessed in initial experiments by α-actinin staining. Preload was then set to 1.5 mN/mm 2 in all slices to obtain a resting sarcomere length between 2.0 and 2.1 µm (see Supplementary Figure S2), which is close to the optimum suggested for stable cultivation of myocardial tissue (Watson et al, 2019).…”

Physiological Biomimetic Culture System for Pig and Human Heart Slices

“…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] .…”