HYPOXIA MODULATES THE BARRIER AND COAGULANT FUNCTION OF CULTURED BOVINE ENDOTHELIUM - INCREASED MONOLAYER PERMEABILITY AND INDUCTION OF PROCOAGULANT PROPERTIES
HYPOXIA MODULATES THE BARRIER AND COAGULANT FUNCTION OF CULTURED BOVINE ENDOTHELIUM - INCREASED MONOLAYER PERMEABILITY AND INDUCTION OF PROCOAGULANT PROPERTIES
复制标题
DOI：
10.1172/jci114540
复制
发表时间：
1990-04-01
影响因子：
15.9
通讯作者：
STERN, D
中科院分区：
文献类型：
--
作者：
OGAWA, S;GERLACH, H;STERN, D
培养的内皮细胞暴露于低浓度氧的环境中，在体内病理生理低氧状态下观察到的范围内，会损害细胞屏障和凝血功能。含PO 2的大气14 mm Hg对内皮细胞培养物没有致死毒性，但细胞变大，并显示出小的细胞间间隙。在低氧浓度下，大分子示踪剂通过缺氧的内皮细胞单层的通道加速在时间和剂量依赖性的方式，大概是通过一个旁细胞途径的差距。内皮细胞表面凝血特性也受到干扰。在PO 2处14 mm Hg血栓调节蛋白抗原和细胞表面的功能活性降低了80- 90%，北方印迹证明了血栓调节蛋白mRNA的抑制。血栓调节蛋白的减少是缺氧条件下总蛋白合成下降的两倍。此外，直接因子X激活剂的表达在缺氧条件下发展;该激活剂是膜相关的，并在完整培养物的表面上表达，Ca依赖性，受HgCl 2抑制，但不受PMSF抑制，并具有Km。25 μ g/ml。通过在培养基中加入放线菌酮而不是华法林来阻断激活剂的合成。这些结果表明，在低浓度氧的存在下，内皮功能被干扰的选择性的方式，提供的机制，这可能有助于在低氧状态下的血管功能障碍的见解。
Exposure of cultured endothelium to environments with low concentrations of oxygen, in the range of those observed in pathophysiologic hypoxemic states in vivo, compromises cellular barrier and coagulant function. An atmosphere with PO2 .apprxeq. 14 mm Hg was not lethally toxic to endothelial cultures, but cells became larger and exhibited small intercellular gaps. At low oxygen concentrations, passage of macromolecular tracers through hypoxic endothelial monolayers was accelerated in a time- and dose-dependent manner, presumably by a paracellular pathway via the gaps. Cell surface coagulant properties of the endothelium were also perturbed. At PO2 .apprxeq. 14 mm Hg thrombomodulin antigen and functional activity on the cell surface were diminished by 80-90%, and Northern blots demonstrated suppression of thrombomodulin mRNA. The decrease in thrombomodulin was twice as great compared with the general decline in total protein synthesis in hypoxia. In addition, expression of a direct Factor X activator developed under hypoxic conditions; the activator was membrane-associated and expressed on the surface of intact cultures, Ca-dependent, inhibited by HgCl2 but not PMSF, and had Km .apprxeq. 25 .mu.g/ml for the substrate at pH 7.4. Synthesis of the activator was blocked by inclusion of cycloheximide, but not warfarin, in the culture medium. These results demonstrate that endothelial function is perturbed in a selective manner in the presence of low concentrations of oxygen, providing insights into mechanisms which may contribute to vascular dysfunction in hypoxemic states.