The FRESH method of bioprinting the heart for transplantation

Cardiovascular disease is the second leading cause of death in Canada [1,2]. Artificial transplantation is often required for those with end-stage cardiovascular disease due to the inability for cardiac tissue to regenerate [3]. Currently, ventricular assist devices and total artificial hearts serve as temporary mechanical replacements for the dozens of individuals on the transplant list, but it is estimated that 50% of these patients will never receive a transplant due to limited donor hearts [4]. Bioprinting hearts can better meet patient demands, thus revolutionizing the field of transplantation. While there have been three-dimensional (3D) prints of arteries and other low complexity biological parts, fully functional hearts are still under development. The main challenges of bioprinting a heart include soft bioinks, cell viability, complex internal geometry, and clinical implementation.