Development of In-Body Tissue-Engineered, Completely Autologous Valve (BIOVALVE)

Abstract

AbstractUsing simple, safe, and economical in-body tissue engineering, autologous valved conduits (BIOVALVEs) with the sinus of Valsalva and without any artificial support materials were developed in animal recipients’ bodies. In this study, the feasibility of theBIOVALVE as an aortic valve was evaluated in a goat model. BIOVALVEs were prepared by 2-month embedding of the molds, assembled using 2 types of specially designed plastic rods, in the dorsal subcutaneous spaces of goats. One rod had 3 projections, resembling the protrusions of the sinus of Valsalva. Completely autologous connective tissue BIOVALVEs with 3 leaflets in the inner side of the conduit with the sinus of Valsalva were obtained after removing the molds from both terminals of the harvested implants with complete encapsulation. The BIOVALVE leaflets had appropriate strength and elastic characteristics similar to those of native aortic valves; thus, a robust conduit was formed. Tight valvular coaptation and sufficient open orifice area were observed in vitro. BIOVALVEs (n=3) were implanted in the specially designed apico-aortic bypass for 2 months as a pilot study under the systemic circulation. Postoperative echocardiogram and angiogram showed smooth movement of the leaflets with little regurgitation (2.6 ±1.1 L/min). The α-SMA–positive cells migrated in the tissue of the conduit significantly with rich angiogenesis and expanded toward the leaflet tip. At the sinus portions, marked elastic fibers were formed. The luminal surface was covered with thin pseudointima without thrombus formation. Completely autologous BIOVALVEs with robust and elastic characteristics satisfied the higher requirements of systemic circulation in goats for 2 months with the potential for valvular tissue regeneration.