The Glycocalyx of the Human Umbilical Vein Endothelial Cell An Impressive Structure Ex Vivo but Not in Culture
The Glycocalyx of the Human Umbilical Vein Endothelial Cell An Impressive Structure Ex Vivo but Not in Culture
复制标题
DOI：
10.1161/circresaha.108.187831
复制
发表时间：
2009-06-05
影响因子：
20.1
通讯作者：
Becker, Bernhard F.
中科院分区：
文献类型：
--
作者：
Chappell, Daniel;Jacob, Matthias;Becker, Bernhard F.
Potter 和 Damiano 最近使用荧光微粒图像测速法评估了体内（小鼠提睾肌小静脉）和体外（在灌注微通道中培养的人脐静脉和牛主动脉内皮）内皮糖萼的流体动力学尺寸（Circ Res. 2008；102：770-776）。观察到了很大的差异，糖萼呈现出一个相互作用区，在体内延伸到血管腔内约0.52μm，但距离培养细胞仅0.02至0.03μm。在随附的社论中，Barakat 警告说，流体动力学相互作用的差异不允许我们得出培养细胞完全缺乏能够进行机械转导的物理细胞表面层的结论（Circ Res. 2008；102：747-748）。为了稳定电子显微镜研究的糖萼，我们用镧/戊二醛溶液灌注固定了 6 条人脐静脉以及人脐静脉内皮细胞 (HUVEC) 的汇合和非汇合培养物（各 5 个）。离体时，脐静脉内皮糖萼厚度平均为878 nm。 HUVEC 体外呈现出密集区厚度仅为 29.4 nm 的糖萼，加上平均延伸至 118 nm 的稀疏细丝，非汇合细胞和汇合细胞之间没有差异。免疫组织学证明了硫酸乙酰肝素和 Syndecan-1（糖萼的主要成分）的存在，无论是体外还是体外。这些结果支持了在体内和体外观察到的糖萼厚度之间的差异，现在对于一种相同类型的人类细胞而言。培养细胞上也存在硫酸乙酰肝素和 syndecan-1，这可以解释为什么即使在未成熟的糖萼中也可以观察到机械转导现象。 （Circ Res. 2009；104：1313-1317。）
Potter and Damiano recently assessed the hydrodynamic dimensions of the endothelial glycocalyx in vivo (mouse cremaster muscle venules) and in vitro (human umbilical vein and bovine aorta endothelium cultured in perfused microchannels) using fluorescent microparticle image velocimetry (Circ Res. 2008; 102: 770-776). Great discrepancy was observed, the glycocalyx presenting a zone of interaction extending approximate to 0.52 mu m into the vessel lumen in vivo, but only 0.02 to 0.03 mu m from cultured cells. In an accompanying editorial, Barakat cautioned that the difference in hydrodynamic interaction did not allow one to conclude that the cultured cells totally lack a physical cell surface layer capable of mechanotransduction (Circ Res. 2008; 102: 747-748). To stabilize the glycocalyx for electron microscopic investigation, we perfusion-fixed 6 human umbilical veins and confluent and nonconfluent cultures (5 each) of human umbilical vein endothelial cells (HUVECs) with lanthanum/glutaraldehyde solution. Ex vivo, the thickness of glycocalyx of umbilical vein endothelium averaged 878 nm. HUVECs in vitro presented a glycocalyx with a dense-zone thickness of only 29.4 nm, plus sparse filaments reaching out on average to 118 nm, there being no difference between the nonconfluent and confluent cells. Immunohistology demonstrated the presence of heparan sulfates and syndecan-1, main constituents of the glycocalyx, both ex vivo and in vitro. These results support the observed discrepancy between glycocalyx thickness in vivo and in vitro, now for one and the same type of human cell. The presence of heparan sulfates and syndecan-1 also on cultured cells may explain why mechanotransduction phenomena can be observed even with a nonmature glycocalyx. (Circ Res. 2009; 104: 1313-1317.)