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

Figures

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  Fig. 1.. (A) A schematic illustration of the unfolded mitral valve with anatomical structures viewed from bottom (ventricular leaflet surface exposed). Anterior leaflet, posterior leaflet, strut chordae, basal chordal, marginal chordae, annulus, basal zone, free edge, and papillary muscle were labeled. The circumferential direction and radial direction were also defined. (B) A summary of the performed assays, biaxial mechanical tests, and uniaxial mechanical tests for assessing MV components before and after decellularization.

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  Fig. 2.. (A) Morphology of the native porcine MV AL. (B) Native MV AL cross-sectional histology stained with Movat’s pentachrome; the AL showed the trilayered structure of atrialis, spongiosa, and fibrosa. (C) Native MV AL cross-sectional histology stained with picrosirius red. (D) Native MV AL collagen crimp structure revealed by light-distinguishing bands of polarized light microscopy. (E) Morphology of the decellularized MV AL. (F) Decellularized MV AL cross-sectional histology stained with Movat’s pentachrome; the decellularized AL preserved the trilayered structure of atrialis, spongiosa, and fibrosa. (G) Decellularized MV AL cross-sectional histology stained with picrosirius red. (H) Decellularized MV AL collagen crimp structure revealed by light-distinguishing bands of polarized light microscopy. Note that Movat’s pentachrome stains collagen, elastin, and GAGs as yellow, black, and blue, respectively.

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  Fig. 3.. (A) Morphology of the native porcine MV PL. (B) Native MV PL cross-sectional histology stained with Movat’s pentachrome; the PL showed the trilayered structure of atrialis, spongiosa, and fibrosa. (C) Native MV PL cross-sectional histology stained with picrosirius red. (D) Native MV PL collagen crimp structure revealed by light-distinguishing bands of polarized light microscopy. (E) Morphology of the decellularized MV PL. (F) Decellularized MV PL cross-sectional histology stained with Movat’s pentachrome; the decellularized PL preserved the trilayered structure of atrialis, spongiosa, and fibrosa. (G) Decellularized MV PL cross-sectional histology stained with picrosirius red. (H) Decellularized MV PL collagen crimp structure revealed by light-distinguishing bands of polarized light microscopy. Note that Movat’s pentachrome stains collagen, elastin, and glycosaminoglycans (GAGs) as yellow, black, and blue, respectively.

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  Fig. 4.. (A) Longitudinal histology of the native strut chordae stained with Movat’s pentachrouter elastin sheath. (B) Longitudinal histology of the decellularized strut chordae stained with Movat’s pentachrome; the strut chordae preserved the overall microstructural morphology. (C) Cross-sectional histology of the native strut chordae stained with Movat’s pentachrome. (D) Native strut chordae longitudinal histology stained with picrosirius red. (E) Native strut chordae crimp structure revealed by light-distinguishing bands of polarized light microscopy. (F) Cross-sectional histology of the decellularized strut chordae stained with Movat’s pentachrome. (D) Decellularized strut chordae longitudinal histology stained with picrosirius red. (E) Decellularized strut chordae crimp structure revealed by light-distinguishing bands of polarized light microscopy.

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  Fig. 5.. Longitudinal histology of the native basal chordae stained with Movat’s pentachrome; the strut chordae showed the thick dense collagen fiber core and the thin outer elastin sheath. (B) Cross-sectional histology of the native basal chordae stained with Movat’s pentachrome. (C) Native basal chordae longitudinal histology stained with picrosirius red. (D) Native basal chordae crimp structure revealed by light-distinguishing bands of polarized light microscopy. (E) Longitudinal histology of the decellularized basal chordae stained with Movat’s pentachrome; the basal chordae preserved the overall microstructural morphology. (F) Cross-sectional histology of the decellularized basal chordae stained with Movat’s pentachrome. (G) Decellularized basal chordae longitudinal histology stained with picrosirius red. (E) Decellularized basal chordae crimp structure revealed by light-distinguishing bands of polarized light microscopy.

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  Fig. 6.. Results of Griffonia simplicifolia (GS) lectin immunohistochemistry assay. Histochemical staining for a-Gal: (A) Native AL; (B) Decellularized AL; (C) Native PL; (D) Decellularized PL; (E) Native strut chordae; (F) Decellularized strut chordae; (G) Native basal chordae; (H) Decellularized basal chordae. Images for the native tissues (A, C, E, G) showed that a-Gal antigen (brown color) was associated cells in AL, PL, strut chordae, and basal chordae; insert shows negative controls where lectin was omitted. Images for the acellular scaffolds (B, D, F, H) demonstrated that α-Gal antigen was completely absent in the decellularized AL, PL, strut chordae, and basal chordae.

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  Fig. 7.. SEM images: (A) Native AL; (B) Native PL; (C) Native strut chordae; (D) Native basal chordae; (E) Decellularized AL; (F) Decellularized PL; (G) Decellularized strut chordae; (H) Decellularized basal chordae.

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  Fig. 8.. Biaxial tension-stretch curves for (A) Native AL, (B) Decellularized AL, (C) Native PL, and (E) Decellularized PL.

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  Fig. 9.. Uniaxial stress-strain curves up to failure. (A) Native AL and decellularized AL, circumferential direction. (B) Native AL and decellularized AL, radial direction. (C) Native PL and decellularized PL, circumferential direction. (D) Native PL and decellularized PL, radial direction. (E) Native strut chordae and decellularized strut chordae. (F) Native basal chordae and decellularized basal chordae.