In-body tissue-engineered aortic valve (Biovalve type VII) architecture based on 3D printer molding Yasuhide Nakayama, 1 Yoshiaki Takewa, 2 Hirohito Sumikura, 2 Masashi Yamanami, 1,3 Yuichi Matsui, 1,4 Tomonori Oie, 1 Yuichiro Kishimoto, 2 Mamoru Arakawa, 2 Kentaro Ohmuma, 2 Tsutomu Tajikawa, 4 Keiichi Kanda, 3 Eisuke Tatsumi 2 1 Division of Medical Engineering and Materials, National Cerebral and Cardiovascular Center Research Institute, Osaka, Japan 2 Department of Artificial Organs, National Cerebral and Cardiovascular Center Research Institute, Osaka, Japan 3 Department of Cardiovascular Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan 4 Department of Mechanical and Systems Engineering, Kansai University, Osaka, Japan Received 27 November 2013; revised 15 March 2014; accepted 12 April 2014 Published online 25 April 2014 in Wiley Online Library (wileyonlinelibrary.com). DOI: 10.1002/jbm.b.33186 Abstract: In-body tissue architecture—a novel and practical regeneration medicine technology—can be used to prepare a completely autologous heart valve, based on the shape of a mold. In this study, a three-dimensional (3D) printer was used to produce the molds. A 3D printer can easily reproduce the 3D-shape and size of native heart valves within several processing hours. For a tri-leaflet, valved conduit with a sinus of Valsalva (Biovalve type VII), the mold was assembled using two conduit parts and three sinus parts produced by the 3D printer. Biovalves were generated from completely autologous connective tissue, containing collagen and fibro- blasts, within 2 months following the subcutaneous embed- ding of the molds (success rate, 27/30). In vitro evaluation, using a pulsatile circulation circuit, showed excellent valvular function with a durability of at least 10 days. Interposed between two expanded polytetrafluoroethylene grafts, the Biovalves (N 5 3) were implanted in goats through an apico- aortic bypass procedure. Postoperative echocardiography showed smooth movement of the leaflets with minimal regurgitation under systemic circulation. After 1 month of implantation, smooth white leaflets were observed with mini- mal thrombus formation. Functional, autologous, 3D-shaped heart valves with clinical application potential were formed following in-body embedding of specially designed molds that were created within several hours by 3D printer. V C 2014 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 103B: 1–11, 2015. Key Words: tissue engineering, heart valve, 3D printer, con- nective tissue, surgery How to cite this article: Nakayama Y, Takewa Y, Sumikura H, Yamanami M, Matsui Y, Oie T, Kishimoto Y, Arakawa M, Ohmuma K, Tajikawa T, Kanda K, Tatsumi E. 2015. In-body tissue-engineered aortic valve (Biovalve type VII) architecture based on 3D printer molding. J Biomed Mater Res Part B 2015:103B:1–11. INTRODUCTION Surgical alternatives for end-stage valvular heart disease con- sist of the application of either mechanical or biological pros- theses, both of which have significant limitations. 1 Although mechanical valves have a functional life span of at least 25 years, they are associated with the need for life-long anticoa- gulation and the concomitant risks of thromboembolism and bleeding. Biological prostheses, generally, have better hemo- dynamic characteristics and do not require long-term anti- coagulation, but are associated with progressive tissue deterioration. Therefore, tissue-engineering techniques may play a prominent role in the future development of heart valve replacements. Much of the research designed to create in vitro tissue-engineered heart valves has focused on the scaffold materials, culturing of cells, and the use of appropri- ate seeding and preconditioning protocols. 2,3 However, the mechanical integrity of the replacement valves and their abil- ity to withstand systemic pressures depends on the neo- tissue. Therefore, the clinical utility of these autologous tissue-engineered heart valves is limited, particularly in grow- ing children. The medical and engineering relevance of computer- based three-dimensional (3D) procedures—known as 3D printing—is increasing, which increases the potential of rapid prototyping techniques. 4,5 The technology presented in this paper is based on the principle of building 3D mod- els, layer by layer, and enables the direct manufacturing of precise, complex-shaped implants using biocompatible or biodegradable materials from computerized data in several medical areas. 6–9 As a feasible, regenerative medicine approach, we devel- oped completely autologous valved conduits, named Bio- valves, 10–12 without any artificial scaffolds, through the use of “in-body tissue architecture” technology. This autologous Correspondence to: Y. Nakayama (e-mail: ny@ncvc.go.jp) Contract grant sponsor: Ministry of Education, Culture, Sports, Science, and Technology of Japan; contract grant number: B23360374 V C 2014 WILEY PERIODICALS, INC. 1