3-dimensional structures to enhance cell therapy and engineer contractile tissue.

Experimental studies in animals and recent human clinical trials have revealed the current limitations of cellular transplantation, which include poor cell survival, lack of cell engraftment, and poor differentiation. Evidence in animals suggests that use of a 3-dimensional scaffold may enhance cell therapy and engineer myocardial tissue by improving initial cell retention, survival, differentiation, and integration. Several scaffolds of synthetic or natural origin are under development. Until now, contractility has been demonstrated in vitro only in biological scaffolds prepared from decellularized organs or tissue, or in collagenic porous scaffold obtained by crosslinking collagen fibers. While contractility of a cellularized collagen construct is poor, it can be greatly enhanced by tumor basement membrane extract. Recent advances in biochemistry have shown improved cell-matrix interactions by coupling adhesion molecules to achieve an efficient and safe bioartificial myocardium with no tumoral component. Fixation of adhesion molecules may also be a way to enhance cell homing and/or differentiation to increase local angiogenesis. Whatever the clinically successful combination ultimately proves to be, it is likely that cell therapy will require providing a supportive biochemical, physical, and spatial environment that will allow the cells to optimally differentiate and integrate within the target myocardial tissue.