Little is known about endothelium-dependent regulation of valve tone and function. The aim of this study was to evaluate the effects of endogenous vasoactive mediators on the mechanical properties of aortic valve leaflets and to investigate the influence of the endothelium. Normal porcine aortic valve leaflets were evaluated using a biaxial micromechanical testing apparatus to measure the tissue modulus of the aortic valve in response to serotonin, L-NAME, endothelin-1 (ET-1), cytochalasin B (CyB), sodium nitroprusside (SNP) and KCl. Our data demonstrated a significant role for endothelium-dependent regulation of aortic valve mechanical properties. Moreover, valve stiffness was mediated by the contractile apparatus of valve interstitial cells. These findings underline the importance of valve cells and offer an insight into valvular diseases associated with increased levels of ET-1 or 5-HT.

Dr. Ajit Yoganathan has been active in the areas of cardiovascular fluid mechanics, cardiovascular devices and biomedical engineering for the past two decades. He has conducted pioneering fundamental research on the fluid mechanics of artificial heart valves and has published extensively in this field. His recent work concentrates on using cardiac Doppler ultrasound and magnetic resonance imaging for non-invasively studying blood flow patterns in the heart. This work has led to techniques that for the very first time permit quantitative analysis of valvular regurgitation. Dr. Yoganathan’s research is supported by both government and industrial organizations. His medical collaborations include the Massachusetts General Hospital, University of Alabama- Birmingham, Emory University, University of North Carolina, and NIH. In 1985 Dr. Yoganathan was awarded an Alexander von Humboldt Fellowship from West Germany to spend nine months at the Helmholtz Institute for Biomedical Research, Technical University of Aachen. In 1988, he received the Edwin Walker Prize from the Institute of Mechanical Engineers, U.K., and in 1992 he was elected a Founding Fellow of the American Institute of Medical and Biological Engineering. This year he will receive the H.R. Lissner Award from ASME. In 1992 he spent 6 months in Denmark as a Visiting Professor of the Danish Research Academy. He is a member of the International Standards Organization Subcommittee on Artificial Heart Valves, and a past member (1988-91) of the NIH Surgery and Bioengineering Study Section. He is currently chairman of the ASME Biofluid Mechanics Committee. Dr. Yoganathan is a consultant to the FDA and the heart valve and cardiac ultrasound industries.

Dr. Robert Nerem joined Georgia Tech in 1987 when he was appointed as the Parker H. Petit Professor for Engineering in Medicine. In 1995 he was appointed Director of the Parker H. Petit Institute for Bioengineering and Bioscience and in 1998 Director of the Georgia Tech/Emory Center for the Engineering of Living Tissues, a National Science Foundation Engineering Research Center. Professor Nerem is the author of more than 120 refereed journal articles. He is a Past President of both the International Union for Physical and Engineering Sciences in Medicine and the International Federation for Medical and Biological Engineering. He also is a Past-Chairman of the U.S. National Committee on Biomechanics and was Technical Editor, ASME Journal of Biomechanical Engineering from 1988 to 1997. He is a Fellow, Council of Arteriosclerosis, American Heart Association, American Physical Society; Fellow, American Society of Mechanical Engineers; and Fellow, American Association for the Advancement of Science. In 1988 Professor Nerem was elected to the National Academy of Engineering and in 1992 to the Institute of Medicine of the National Academy of Sciences.

Researchers should cite this work as follows:

• (2009), "IREE: GTEC and Imperial College, London, UK for Tissue Engineering Collaborations," http://globalhub.org/resources/881.

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1. iree 2007
2. trip report