Mimicking cardiac tissue complexity through physical cues: A review on cardiac tissue engineering approaches.

Cardiovascular diseases are the number one killer in the world. ^1,2 Currently, there are no clinical treatments to regenerate damaged cardiac tissue, leaving patients to develop further life-threatening cardiac complications. Cardiac tissue has multiple functional demands including vascularization, contraction, and conduction that require many synergic components to properly work. Most of these functions are a direct result of the cardiac tissue structure and composition, and, for this reason, tissue engineering strongly proposed to develop substitute engineered heart tissues (EHTs). EHTs usually have combined pluripotent stem cells and supporting scaffolds with the final aim to repair or replace the damaged native tissue. However, as simple as this idea is, indeed, it resulted, after many attempts in the field, to be very challenging. Without design complexity, EHTs remain unable to mature fully and integrate into surrounding heart tissue resulting in minimal in vivo effects. ³ Lately, there has been a growing body of evidence that a complex, multifunctional approach through implementing scaffold designs, cellularization, and molecular release appears to be essential in the development of a functional cardiac EHTs. ^4–6 This review covers the advancements in EHTs developments focusing on how to integrate contraction, conduction, and vascularization mimics and how combinations have resulted in improved designs thus warranting further investigation to develop a clinically applicable treatment. Optimizing cellular complexity, mechanical stimulation, electrical stimulation, matrix design, and vascularization through mimicking embryogenesis and development will result in full thickness, functional clinical patches for treating heart conditions. [Display omitted] • Current cell cardiac patches are limited in functionality in large models likely due to complexity. • Mimicking the embryogenesis through tissue complexity and developmental cues may improve maturation. • Vascularization, conduction, and contraction are important properties to optimize. • Many different types of stimulations improve maturation of cardiomyocytes. [ABSTRACT FROM AUTHOR]