Structural and biomechanical characterizations of acellular porcine mitral valve scaffolds: anterior leaflets, posterior leaflets, and chordae tendineae.
Structural and biomechanical characterizations of acellular porcine mitral valve scaffolds: anterior leaflets, posterior leaflets, and chordae tendineae.
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DOI：
10.1016/j.engreg.2022.08.003
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发表时间：
2022-12-01
影响因子：
--
通讯作者：
Liao, Jun
中科院分区：
文献类型：
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作者：
Wang, Bo;Sierad, Leslie N;Liao, Jun
二尖瓣组织工程仍处于早期阶段，二尖瓣组织工程的主要挑战之一是寻找合适的支架材料。随着近年来脱细胞MV支架的潜力被证明，充分了解天然MV成分及其脱细胞支架的生物力学是很重要的。在这项研究中，我们成功地表征了猪MV组件的结构和力学特性，包括前小叶（AL），后小叶（PL），支柱脊索和基底脊索，脱细胞前后。定量DNA分析显示DNA含量降低90%以上，免疫组化证实脱细胞MV成分中完全缺乏猪α - gal抗原。在脱细胞AL和PL中，心房、海绵和纤维的三层结构及其ECM组成，即胶原纤维、弹性蛋白纤维和部分gag被保留。然而，AL和PL的ECM都经历了一定程度的破坏，表现出较不致密的多孔ECM形态。脱细胞后，支撑和基索的整体解剖形态也保持不变，纵向形态受到最小的破坏，但横截面形态呈现均匀分布的多孔结构。在非细胞AL和PL中，非线性各向异性双轴力学行为总体保持不变；然而，单轴拉伸试验表明，细胞内容物的去除和结构ECM的破坏确实导致MV小叶和索的最大拉伸模量、组织伸伸性、破坏应力和破坏应变的小幅下降。
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 alpha-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 decreases in maximum tensile modulus, tissue extensibility, failure stress, and failure strain for both MV leaflets and chordae.