Structural and biomechanical characterizations of acellular porcine mitral valve scaffolds: anterior leaflets, posterior leaflets, and chordae tendineae

• Published in: Engineered regeneration 2022-12, Vol.3 (4), p.374-386
• Main Authors: Wang, Bo, Sierad, Leslie N., Mercuri, Jeremy J., Simionescu, Agneta, Simionescu, Dan T., Williams, Lakiesha N., Vela, Ryan, Bajona, Pietro, Peltz, Matthias, Ramaswamy, Sharan, Hong, Yi, Liao, Jun
• Format: Article
• Language: English
• Subjects: Chordae tendineae; Decellularization; Heart valve biomechanics; Mitral valve tissue engineering; Valve leaflets
• ISSN: 2666-1381; 2666-1381
• DOI: 10.1016/j.engreg.2022.08.003

•Quantitative DNA assay showed more than 90% reduction in DNA content, and griffonia simplicifolia (GS) lectin immunohistochemistry confirmed the complete lack of porcine α-Gal antigen in the acellular MV components.•In the acellular AL and PL, the atrialis, spongiosa, and fibrosa trilayered structure, along with its ECM constitutes, i.e., collagen fibers, elastin fibers, and a portion of GAGs, were preserved.•The overall anatomical morphology of thick dense collagen fiber core and the thin outer elastin sheath in the strut chordae and basal chordae were also maintained after decellularization.•In the acellular AL and PL, the nonlinear anisotropic biaxial mechanical behavior was overall preserved, and the acellular strut chordae and acellular basal chordae both preserved the nonlinear J-shaped stress-strain behavior of the native chordae. Mitral valve (MV) tissue engineering is still in its early stage, and one major challenge in MV tissue engineering is to identify appropriate scaffold materials. With the potential of acellular MV scaffolds being demonstrated recently, it is important to have a full understanding of the biomechanics of the native MV components and their acellular scaffolds. In this study, we have successfully characterized the structural and mechanical properties of porcine MV components, including anterior leaflet (AL), posterior leaflet (PL), strut chordae, and basal chordae, before and after decellularization. Quantitative DNA assay showed more than 90% reduction in DNA content, and Griffonia simplicifolia (GS) lectin immunohistochemistry confirmed the complete lack of porcine α-Gal antigen in the acellular MV components. In the acellular AL and PL, the atrialis, spongiosa, and fibrosa trilayered structure, along with its ECM constitutes, i.e., collagen fibers, elastin fibers, and portion of GAGs, were preserved. Nevertheless, the ECM of both AL and PL experienced a certain degree of disruption, exhibiting a less dense, porous ECM morphology. The overall anatomical morphology of the strut and basal chordae were also maintained after decellularization, with longitudinal morphology experiencing minimum disruption, but the cross-sectional morphology exhibiting evenly-distributed porous structure. In the acellular AL and PL, the nonlinear anisotropic biaxial mechanical behavior was overall preserved; however, uniaxial tensile tests showed that the removal of cellular content and the disruption of structural ECM did result in small decrease