目的:对肠系膜上动脉(SMA)壁的组织学和纤维结构进行定量分析,进一步探讨血管壁的结构和组织学变化与相关疾病发生的可能关系。
方法:对从22具尸体获得的SMA标本进行了组织学和纤维结构分析。SMA标本分为初始,弯曲的,和远端段,每节分为前壁和后壁。
结果:从初始到弯曲到远端段,弹性蛋白的比率下降(31.4%±6.0%,21.1%±5.8%,18.6%±4.7%,分别;P<.001),而平滑肌肌动蛋白的比例(24.5%±8.7%,30.5%±6.8%,36.1%±7.3%,分别;P<.001)增加。弹性纤维纵向波幅角起伏(AAU)在初始段[7°(3.25°,15°)],曲线段最低[2°(1°,5°)]。在SMA弯曲段中,前壁,与后壁相比,显示弹性蛋白(19.0%±5.8%vs23.3%±5.0%;P=.010)和胶原蛋白(41.4%±12.3%vs49.0%±10.2%;P=.032)的比例较低,下弹性纤维纵向AAU[1°(1°,5°)vs3°(2°,5.25°);P=.013],较低的AFD(8.06±0.36像素对8.45±0.50像素;P=0.005),和较低的ASL(17.96±1.59像素对20.05±2.33像素;P=.001)。
结论:SMA壁结构沿圆周和轴向变化,致密的波状弹性纤维的存在可以保护SMA的初始部分免受夹层和动脉瘤的影响,但是高度交联的胶原纤维会增加斑块形成的可能性。在弯曲段的前壁,较低的弹性蛋白和胶原蛋白含量,较低的弹性纤维起伏,较高程度的胶原纤维交联导致SMA夹层和动脉瘤的发生。在远端段,高水平的血管平滑肌细胞和长胶原纤维束提供预防SMA相关疾病的发展。
BACKGROUND: To quantitatively analyze histological and fiber structure of the superior mesenteric artery (SMA) wall and to further explore the possible relationship between the architecture and histology changes of vessel wall and the occurrence of related diseases.
METHODS: Histological and fiber structure analysis were performed on SMA specimens obtained from 22 cadavers. The SMA specimens were divided into initial, curved, and distal segments, and each segment was separated into the anterior and posterior walls.
RESULTS: From the initial to the curved to the distal segment, the ratio of
elastin decreased (31.4% ± 6.0%, 21.1% ± 5.8%, 18.6% ± 4.7%, respectively; P < 0.001), whereas the ratio of smooth muscle actin (24.5% ± 8.7%, 30.5% ± 6.8%, 36.1% ± 7.3%, respectively; P < 0.001) increased. Elastic fiber longitudinal amplitude of angular undulation was highest in the initial segment [7° (3.25°, 15°)] and lowest in the curved segment [2° (1°, 5°)]. In SMA curved segment, the anterior wall, when compared with the posterior wall, demonstrated a lower ratio of
elastin (19.0% ± 5.8% vs. 23.3% ± 5.0%; P = 0.010) and collagen (41.4% ± 12.3% vs. 49.0% ± 10.2%; P = 0.032), a lower elastic fiber longitudinal amplitude of angular undulation [1° (1°, 5°) vs. 3° (2°, 5.25°); P = 0.013], a lower average fiber diameter (8.06 ± 0.36 pixels vs. 8.45 ± 0.50 pixels; P = 0.005), and a lower average segment length (17.96 ± 1.59 pixels vs. 20.05 ± 2.33 pixels; P = 0.001).
CONCLUSIONS: SMA wall structure varies along the circumferential and axial directions, the presence of dense undulated elastic fiber protects the SMA initial segment of from dissection and aneurysm, but highly cross-linked collagen fiber here increases the likelihood of plaque formation. In the anterior wall of the curved segment, lower
elastin and collagen content, lower elastic fiber undulation, and higher degree of collagen fiber cross-linking leads to the occurrence of SMA dissection and aneurysm. In the distal segment, high levels of vascular smooth muscle cells and bundles of long collagen fiber offer protection against the development of SMA-related diseases.