In vivo tissue engineering an autologous semilunar biovalve: Can we get what we want?

Neural crest cells migrate to left ventricular outflow tract, contributing to development of semilunar valves. LA, Left atrium; RA, right atrium; LV, left ventricle; RV, right ventricle. From Hagmann M. A gene that scrambles your heart. Science. 1999;283:1091-3. Reprinted with permission of Nature Publishing Group.

A, Endoscopic view into sinus of Valsalva of pressurized porcine aortic root. B, Inset of A, near annulus, strong collagen fibers bear thin, hammock-shaped membranes. C, Smaller collagen fibers are embedded in these membranes (arrows). D, This structural arrangement is shown histologically after fixation under load; red color indicates collagen. (Van Gieson staining courtesy W. Kühnel, Institute of Anatomy, University of Luebeck, Luebeck, Germany.) E, Collagen fibers possess wavy, crimped configuration (Fastenrath S. Texture of collagenous fibers of the aortic/pulmonic valve [thesis]. Kiel, Germany: Univ. of Kiel; 1995.). Reprinted with permission of Sven Fastenrath.

Receptor-mediated contraction of aortic valve leaflets. 5-HT, 5-Hydroxy-l-tryptophan. From Chester AH, Misfeld M, Yacoub MH. Receptor-mediated contraction of aortic valve leaflets. J Heart Valve Dis. 2000;9:250-5. Reprinted with permission from The Journal of Heart Valve Disease.

In codfish hearts, there are two semilunar valves and sinuses of Valsalva located in series in conus arteriosus (C). 1, First semilunar valve; 2, second semilunar valve; M, ventricular muscle.