Establishing the Framework for Tissue Engineered Heart Pumps.

Development of a natural alternative to cardiac assist devices (CADs) will pave the way to a heart failure therapy which overcomes the disadvantages of current mechanical devices. This work provides the framework for fabrication of a tissue engineered heart pump (TEHP). Artificial heart muscle (AHM) was first fabricated by culturing 4 million rat neonatal cardiac cells on the surface of a fibrin gel. To form a TEHP, AHM was wrapped around an acellular goat carotid artery (GCA) and a chitosan hollow cylinder (CHC) scaffold with either the cardiac cells directly contacting the construct periphery or separated by the fibrin gel. Histology revealed the presence of cardiac cell layer cohesion and adhesion to the fibrin gel scaffold, acellular GCA, and synthesized CHC. Expression of myocytes markers, connexin43 and α-actinin, was also noted. Biopotential measurements revealed the presence of ~2.5 Hz rhythmic propagation of action potential throughout the TEHP. Degradation of the fibrin gel scaffold of the AHM via endogenous proteases may be used as a means of delivering the cardiac cells to cylindrical scaffolds. Further development of the TEHP model by use of multi-stimulus bioreactors may lead to the application of bioengineered CADs.