Neonatal Mouse–Derived Engineered Cardiac Tissue

Abstract

Rationale Cardiomyocytes cultured in a mechanically active three-dimensional configuration can be used for studies that correlate contractile performance to cellular physiology. Current engineered cardiac tissue (ECT) models employ cells derived from either rat or chick hearts. Development of a murine ECT would provide access to many existing models of cardiac disease, and open the possibility of performing targeted genetic manipulation with the ability to directly assess contractile and molecular variables. Objective To generate, characterize and validate mouse ECT using a physiologically relevant model of hypertrophic cardiomyopathy. Methods and Results We generated mechanically integrated ECT using isolated neonatal mouse cardiac cells derived from both wild type and myosin binding protein C (cMyBP-C) null mouse hearts. The murine ECT's produce consistent contractile forces that follow the Frank-Starling law, accept physiologic pacing. cMyBP-C null ECT show characteristic acceleration of contraction kinetics. Adenoviral-mediated expression of human cMyBP-C in murine cMyBP-C null ECT restores contractile properties to levels indistinguishable from those of wild type ECT. Importantly, the cardiomyocytes used to construct the cMyBP-C−/− ECT have yet to undergo the significant hypertrophic remodeling that occurs in vivo. Thus, this murine ECT model reveals a contractile phenotype that is specific to the genetic mutation rather than to secondary remodeling events. Conclusions Data presented here show mouse ECT to be an efficient and cost effective platform to study the primary effects of genetic manipulation on cardiac contractile function. This model provides a previously unavailable tool to study specific sarcomeric protein mutations in an intact mammalian muscle system.

Engineered Cardiac Tissues Generated from Immature Cardiac and Stem Cell-Derived Cells: Multiple Approaches and Outcomes

“…Immature CM can be isolated from the hearts of developing chick, mouse, and rat embryos to generate ECTs for preclinical investigation (Fig. 46.1) [5][6][7]. These cells mature in vivo or in vitro along timelines proportional to the gestational length of their species of origin.…”

“…The constructs used for cardiac tissue repair include the implantation of multicellular cardiospheres [18], various formulations of 2D cellular sheets [19][20][21][22], and various formulations of 3D tissues [5][6][7][8]13]. The composition of the noncellular constituents varies from minimal constituents for cardiosphere clusters to a range of ECM components [23,24] and growth factors [25][26][27] selected for their ability to facilitate CM survival and functional maturation.…”

“…46.2) [29], sarcomeric protein content, electrophysiologic properties, and the ability to generate substantial force [5][6][7]13].…”

“…While there has been modest success with improvement in cardiac function in some of the early human clinical trials, it is clear that injected or implanted cells do not survive, and functional improvement occurs via paracrine mechanisms. In contrast, rapid advances in tissue engineering over the past two decades have resulted in the generation of functional, multicellular, 3D cardiac tissues with the potential for translation to human cardiac repair and regeneration [5][6][7][8]. This chapter provides a concise overview of some of the key issues in the generation, maturation, and translation of these engineered cardiac tissues (ECTs).…”

Engineering Cardiovascular Regeneration

“…Various systems have been developed to fix the remodeling tissue and provide the mechanical strain necessary for cell orientation between the fixation points. The setup ranges from Velcro-coated glass tubes [94], rings [95], Flexcell chambers [97], and mesoscopic micropost arrays [98] to newer systems in which the fixation posts serve as means to measure contractile force [99,100] (overview in [48]). For cardiac repair, the hydrogel systems can be upscaled, either by employing larger casting molds [101] or assembling of several smaller elements [102].…”