Tissue engineering of functional cardiac muscle: molecular, structural, and electrophysiological studies

Abstract

The primary aim of this study was to relate molecular and structural properties of in vitro reconstructed cardiac muscle with its electrophysiological function using an in vitro model system based on neonatal rat cardiac myocytes, three-dimensional polymeric scaffolds, and bioreactors. After 1 wk of cultivation, we found that engineered cardiac muscle contained a 120- to 160-microm-thick peripheral region with cardiac myocytes that were electrically connected through gap junctions and sustained macroscopically continuous impulse propagation over a distance of 5 mm. Molecular, structural, and electrophysiological properties were found to be interrelated and depended on specific model system parameters such as the tissue culture substrate, bioreactor, and culture medium. Native tissue and the best experimental group (engineered cardiac muscle cultivated using laminin-coated scaffolds, rotating bioreactors, and low-serum medium) were comparable with respect to the conduction velocity of propagated electrical impulses and spatial distribution of connexin43. Furthermore, the structural and electrophysiological properties of the engineered cardiac muscle, such as cellularity, conduction velocity, maximum signal amplitude, capture rate, and excitation threshold, were significantly improved compared with our previous studies.

Proangiogenic scaffolds as functional templates for cardiac tissue engineering

“…High densities of cardiomyocytes were obtained by relying on self-aggregation of cardiomyocytes, the basis for scaffoldfree systems (3)(4)(5)(6)(7)(8). We used a synthetic scaffold designed to organize the cardiomyocytes and facilitate mass transfer (21,(24)(25)(26)(27)(28). Our approach differs from previous scaffold-based attempts in that regions were designed to exclude cardiomyocytes.…”

Injectable Self-Assembling Peptide Nanofibers Create Intramyocardial Microenvironments for Endothelial Cells

“…These grafts can consist of embryonic or neonatal cardiomyocytes seeded in 3-dimensional scaffolds; the cardiac myocytes cultured in these scaffolds can spatially organize and differentiate into myocardium-like 3-dimensional tissue. 4,5 These results suggest that cell therapy and tissue engineering of myocardium have potential for myocardial regeneration or replacement.…”

Cardiac tissue engineering using perfusion bioreactor systems

“…Three-dimensional cardiac tissue constructs that express structural and physiological features characteristic of native cardiac muscle have been engineered in vitro using fetal or neonatal rat cardiac myocytes (CMs) on collagen fibers 2 , fibrous polyglycolic acid scaffolds [3][4][5][6][7] and porous collagen scaffolds [8][9][10] .…”

“…In early studies, cells were seeded onto scaffolds and cultivated in dishes 4,7,8,11 , in spinner flasks 3,4,7 or in rotating vessels 2,4,7 . Inallof these systems, oxygen dissolved in culture medium was transported to the cells by molecular diffusion.…”

“…Inallof these systems, oxygen dissolved in culture medium was transported to the cells by molecular diffusion. Whereas human cardiac muscle is ~1 cm thick, diffusion alone can support only four to seven cell layers, that is, a 100-μm thick layer of viable and compact tissue 3,4,7,12 . We recently measured oxygen gradients in statically grown cardiac constructs and correlated them with the decrease in cell viability and density 13 (Fig.…”