Heart muscle engineering: an update on cardiac muscle replacement therapy.

Cardiac muscle engineering aims at providing functional myocardium to repair diseased hearts and model cardiac development, physiology, and disease in vitro. Several enabling technologies have been established over the past 10 years to create functional myocardium. Although none of the presently employed technologies yields a perfect match of natural heart muscle, it can be anticipated that human heart muscle equivalents will become available after fine tuning of currently established tissue engineering concepts. This review provides an update on the state of cardiac muscle engineering and its utilization in cardiac regeneration. We discuss the application of stem cells including the allocation of autologous cell material, transgenic technologies that may improve tissue structure as well as in vivo engraftment, and vascularization concepts. We also touch on legal and economic aspects that have to be considered before engineered myocardium may eventually be applied in patients and discuss who may be a potential recipient.