(a) Illustrative diagram of the native ovine mitral valve, demonstrating
key anatomical components: two main leaflets (anterior leaflet and posterior
leaflet), annulus, chordae tendineae and papillary muscles, (b) stained
histologic image showing four-layered structure of the MV tissue (A: atrialis,
S: spongiosa, F: fibrosa, V: ventricularis), and (c) transmission electron
microscopy (TEM) image of the intact MVIC residing in the fibrosa layer of the
MVAL, showing the MVIC microenvironment and its alignment with the collagen
fibrils in the circumferential direction (scale bar=1 µm, C:
circumferential direction, and T: transmural direction).