The three-dimensional micro- and nanostructure of the aortic medial lamellar unit measured using 3D confocal and electron microscopy imaging
The three-dimensional micro- and nanostructure of the aortic medial lamellar unit measured using 3D confocal and electron microscopy imaging
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DOI：
10.1016/j.matbio.2007.10.008
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发表时间：
2008-04-01
期刊：
影响因子：
6.9
通讯作者：
Taylor, Charles A.
中科院分区：
文献类型：
--
作者：
O'Connell, Mary K.;Murthy, Sushila;Taylor, Charles A.
动脉壁组成和功能的改变是所有形式的血管疾病的基础。主动脉壁的基本结构和功能单位是内侧板层单位(MLU)。虽然MLU的基本组成和组织是已知的，但三维(3D)微结构细节是脆弱的，这(部分)是由于缺乏微米和纳米尺度的三维数据。我们应用新的电子显微镜和共聚焦显微镜技术，在微米和纳米尺度上获得了所有成分都存在的主动脉中层微结构的3D体积信息。对于大鼠腹主动脉，我们发现内侧弹性蛋白有三种主要形式：约占总弹性蛋白的71%为厚的连续板层，27%为薄的突出的板层间弹性蛋白纤维(IEF)，2%为厚的放射状支柱。弹性蛋白孔不是简单的板层中的孔，而是板层中的凹陷和角接开口。平滑肌细胞(SMC)在板层间弹性蛋白骨架中穿梭，胞浆延伸与IEF相邻，导致椭圆形SMC核大约20个径向倾斜(相对于管腔表面)。胶原纤维被组织成大的、平行的束，紧紧地包裹着SMC核。对胶原束、SMC核和IEF的取向的量化表明，所有这三个主要的内侧成分都以周向为主，这与已报道的生理应力、胶原纤维充盈和组织硬度的周向主导值相关。这张高分辨率的主动脉中膜三维图像显示了MLU的微结构细节，暗示了与主动脉机械特性相关的高度复杂和完整的壁状组织。(C)2007年Elsevier B.V./国际基质生物学学会。版权所有。
Changes in arterial wall composition and function underlie all forms of vascular disease. The fundamental structural and functional unit of the aortic wall is the medial lamellar unit (MLU). While the basic composition and organization of the MLU is known, three-dimensional (3D) microstructural details are tenuous, due (in part) to lack of three-dimensional data at micro- and nano-scales. We applied novel electron and confocal microscopy techniques to obtain 3D volumetric information of aortic medial microstructure at micro- and nano-scales with all constituents present. For the rat abdominal aorta, we show that medial elastin has three primary forms: with approximately 71 % of total elastin as thick, continuous lamellar sheets, 27% as thin, protruding interlamellar elastin fibers (IEFs), and 2% as thick radial struts. Elastin pores are not simply holes in lamellar sheets, but are indented and gusseted openings in lamellae. Smooth muscle cells (SMCs) weave throughout the interlamellar elastin framework, with cytoplasmic extensions abutting IEFs, resulting in approximately 20 radial tilt (relative to the lumen surface) of elliptical SMC nuclei. Collagen fibers are organized as large, parallel bundles tightly enveloping SMC nuclei. Quantification of the orientation of collagen bundles, SMC nuclei, and IEFs reveal that all three primary medial constituents have predominantly circumferential orientation, correlating with reported circumferentially dominant values of physiological stress, collagen fiber recruitment, and tissue stiffness. This high resolution three-dimensional view of the aortic media reveals MLU microstructure details that suggest a highly complex and integrated mural organization that correlates with aortic mechanical properties. (C) 2007 Elsevier B.V./International Society of Matrix Biology. All rights reserved.