Abstract 14509: Three-Dimensional Beating Human Myocardial Tissues Fabricated From Induced Pluripotent Stem Cells and Cell Sheet Technology
The only radical surgical treatment for severe heart failure is heart transplantation. However, the number of donor hearts available for transplant is limited; so many waiting patients die as their disease worsens. Cell therapy offers the possibility to overcome these problems to rescue patients from heart failure.
We fabricated thick scaffold-free 3-dimensional beating human cardiac tissue using cell sheet technology. Cardiomyocytes were differentiated from human induced pluripotent (hiPS) cells to produce cell sheets, and multi-layered to fabricate thick human cardiac tissues. Initially, 3-layer human iPS cardiomyocyte (hiPSCM) sheets were transplanted on the subcutaneous tissues of nude rats. Two weeks later, these sheets were beating macroscopically, while the electrical potential was rhythmic and regular. Histological analyses showed cardiac tissue and functional micro-vascular networks within the layered constructs. After survival of the 3-layer sheets was confirmed, 9-layer hiPSCM sheets were similarly transplanted with a multi-step transplantation procedure. The results showed the 9-layer hiPSCM sheets had survived 2 weeks after transplantation, and the fabricated cardiac tissues were significantly thicker than those of 3-layer sheets (359±161μm n=3 and 165±40μm n=4, P<0.01). Finally, 6-layer hiPSCM cell sheets were transplanted over a branch of the femoral artery and vein in a rat. After 2 weeks, a graft that included the cell sheets on a base of host tissue was resected with a connectable artery and vein. The graft was then transplanted into the neck and connected to an artery and vein of the host. Moreover, the graft had completely survived 1 week after the transplantation. Electron microscope analyses demonstrated that the transplanted hiPSCM sheets had matured in vivo as human cardiac tissue. This was evidenced by an increase in the number of mitochondria and secretory granules in the cytoplasm, and from the elongation of the sarcomeres.
We have shown the successful fabrication and transplantation in vivo of thick transplantable beating human cardiac tissue by layering hiPSCM sheets. These thick hiPSCM tissues could be transplanted directly to the heart to support contraction and circulation in future human clinical trials.
- © 2013 by American Heart Association, Inc.