Transplantation of a decellularized mitral valve complex in pigs

Purpose: Conventional mitral valve replacement is associated with the loss of natural continuity of the mitral valve complex. This study evaluated the morphologic/histological characteristics and function of a decellularized mitral valve used as a transplantable graft. Methods: Hearts excised from pigs were decellularized by perfusion using detergent. Grafts with the mitral annulus, valve, chordae, and papillary muscle isolated from the decellularized heart were then transplanted into recipient pigs. After transplantation, the function of the graft was analyzed through echocardiography. A histological analysis was performed to evaluate the postoperative features of the decellularized graft. Results: The decellularized graft was successfully transplanted in all cases but one. The remaining grafts maintained their morphology and function. They did not exhibit mitral regurgitation or stenosis. Only one animal survived for 3 weeks, and a histological analysis was able to be performed in this case. The transplanted valve was re-covered with endothelial cells. The microvessels in the papillary muscle were recellularized with vascular endothelial cells, and the papillary muscle was completely attached to the papillary muscle of the recipient. Conclusion: The early outcome of decellularized mitral graft transplantation was acceptable. This native organ-derived acellular scaffold is a promising candidate for the replacement of the mitral valve complex.