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Characterization of statically loaded tissue‐engineered mitral valve chordae tendineae
Author(s) -
Shi Yaling,
Vesely Ivan
Publication year - 2004
Publication title -
journal of biomedical materials research part a
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.849
H-Index - 150
eISSN - 1552-4965
pISSN - 1549-3296
DOI - 10.1002/jbm.a.20095
Subject(s) - chordae tendineae , elastin , materials science , tissue engineering , anatomy , fibril , biomedical engineering , biophysics , mitral valve , pathology , biology , medicine
Chordae tendineae are essential to the proper function of the mitral valve. Native chordae contain a dense collagenous core and an outer elastin sheath. We have been using the principle of directed collagen gel shrinkage to fabricate tissue‐engineered mitral valve chordae. Because the microstructure of biologic tissues determines their mechanical behavior, the morphology of collagen and elastin in tissue‐engineered chordae should mimic that of native chordae. The objective of this study, therefore, was to examine the morphology of our tissue‐engineered constructs in comparison to native chordae. A collagen‐cell suspension was cast into silicon rubber wells with microporous anchors at the ends and cultured in an incubator. The anchors allowed shrinkage to occur only transverse to the long axis of the wells, thus creating highly aligned collagen fibril constructs. The collagen constructs were cultured for 8 weeks and characterized mechanically, histologically, and biochemically at different culture time points. Histologic sections showed that in all mature constructs collagen fibers were oriented parallel to the long axis of the constructs. At the edge of the tissue collagen fibers were in general straight, whereas in the middle of the tissue they were wavy. Transmission electron microscopy showed a progressive increase in the density and longitudinal orientation of collagen fibrils with culture time. Light and scanning electron microscopy showed the presence of an elastin sheath around the collagen core. Immunostaining demonstrated that smooth muscle cells differentiate during tissue development and TUNEL assay showed that cells in the interior of the constructs undergo apoptosis. This study has demonstrated that collagen‐cell constructs, with material properties and microstructure similar to native mitral valve chordae, can be developed using static culture. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res 69A: 26–39, 2004