A limitation of cell-based therapy for myocardial repair is the low retention and engraftment of transplanted cells at the target site. Cardiac patches, which consist of cells embedded in a scaffold material, applied to the surface of the heart can overcome this problem, but cell viability limits long-term storage and mass production. Now, Ke Cheng and colleagues report the creation of an ‘off-the-shelf’, cell-free, artificial cardiac patch that is easy to store and improves outcomes in rat and pig models of myocardial infarction (MI).

To create the artificial cardiac patch, the researchers first produced a myocardial extracellular matrix scaffold from decellularized porcine myocardium, which retains its native ultrastructural and material properties. Next, they produced synthetic cardiac stromal cells (CSCs) by encapsulating human CSC-secreted factors in biodegradable microparticles. These synthetic CSCs were then embedded in the extracellular matrix scaffold. Being fully acellular, the cardiac patch could be cryostored for at least 28 days without detrimental effects on the mechanical properties or therapeutic efficacy.

Transplantation of the artificial cardiac patch into a rat model of acute MI reduced the amount of scarring, promoted angiomyogenesis and increased left ventricular ejection fraction compared with animals that received a cardiac patch with no synthetic CSCs or those that received no treatment. Moreover, the artificial cardiac patch was biocompatible and safe in a pig model of acute MI and resulted in a smaller infarct size, less myocardial fibrosis and a larger improvement in ejection fraction than in pigs that received no treatment. The researchers conclude that the artificial patch provides “a clinically feasible, easy-to-store, and cell-free alternative to myocardial repair using cell-based cardiac patches”.