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This Article Full Text Full Text (PDF) All Versions of this Article: 292/6/H2664    most recent 01419.2006v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (2) Citing Articles via Google Scholar Google Scholar Articles by Zeng, Z. Articles by Rumschitzki, D. S. Search for Related Content PubMed PubMed Citation Articles by Zeng, Z. Articles by Rumschitzki, D. S.

Macromolecular transport in heart valves. I. Studies of rat valves with horseradish peroxidase

¹Department of Chemical Engineering and ²Department of Mechanical Engineering, City College of the City University of New York, New York, New York; ³Institute of Biomedical Science of the Academia Sinica, Taipei, Taiwan, Republic of China; and ⁴Department of Medicine, College of Physicians and Surgeons of Columbia University, New York, New York

Submitted 27 December 2006 ; accepted in final form 23 January 2007

The present study aims to experimentally elucidate subtle structural features of the rat valve leaflet and the related nature of macromolecular transport across its endothelium and in its subendothelial space, information necessary to construct a rational theoretical model that can explain observation. After intravenous injection of horseradish peroxidase (HRP), we perfusion-fixed the aortic valve of normal Sprague-Dawley rats and found under light microscopy that HRP leaked through the leaflet's endothelium at very few localized brown spots, rather than uniformly. These spots grew nearly as rapidly with HRP circulation time before euthanasia as aortic spots, particularly when the time axis only included the time the valve was closed. These results suggest that macromolecular transport in heart valves depends not only on the direction normal to, but also parallel to, the endothelial surface and that convection, as well as molecular diffusion, plays an important role in macromolecular transport in heart valves. Transmission electron microscopy of traverse leaflet sections after 4-min HRP circulation showed a very thin (150 nm), sparse layer immediately beneath the endothelium where the HRP concentration was much higher than that in the matrix below it. Nievelstein-Post et al.'s (Nievelstein-Post P, Mottino G, Fogelman A, Frank J. Arterioscler Thromb 14: 1151–1161, 1994) ultrarapid freezing/rotary shadow etching of the normal rabbit valve's subendothelial space supports the existence of this very thin, very sparse "valvular subendothelial intima," in analogy to the vascular subendothelial intima.

valvular subendothelial intima; focal horseradish peroxidase spots; convective transport

This article has been cited by other articles:

				Z. Zeng, Y. Yin, K.-M. Jan, and D. S. Rumschitzki Macromolecular transport in heart valves. II. Theoretical models Am J Physiol Heart Circ Physiol, June 1, 2007; 292(6): H2671 - H2686. [Abstract] [Full Text] [PDF]

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