Hellman L, Smedsröd B, Sandberg H, Pettersson U
Department of Medical Genetics, University of Uppsala, Sweden.
Br J Haematol. 1989 Nov;73(3):348-55. doi: 10.1111/j.1365-2141.1989.tb07751.x.
Different types of liver cells and a few extrahepatic cell types were analysed for the presence and production of factor VIII activity (VIII:C). Only freshly prepared suspensions of rat liver sinusoidal cells and pure monolayer cultures of rat liver endothelial cells (LEC) were found to contain and secrete detectable amounts of the coagulation factor. Secretion of VIII:C by cultured LEC was inhibited by cycloheximide and by monensin. Constant levels of VIII:C were produced for at least 48 h suggesting continuous synthesis rather than a burst release of stored material. VIII:C, as measured spectro-photometrically by conversion of X to Xa, was inhibited by anti-human VIII:C antiserum. Indirect immunocytochemistry using this antiserum gave positive staining only with LEC. Immunoprecipitation of metabolically labelled proteins in conditioned rat LEC medium with the anti human VIII:C antiserum revealed the presence of proteins of similar sizes to those reported for human VIII:C. These results indicate that rat LEC are an important site for production and secretion of procoagulant factor VIII and are not only a site for storage and release of the factor. The established conditions for synthesis of VIII:C in in vitro cultivated rat LEC should provide the means to study the regulation of VIII:C synthesis.
对不同类型的肝细胞和一些肝外细胞类型进行了分析，以检测因子VIII活性（VIII:C）的存在和产生情况。结果发现，只有新鲜制备的大鼠肝窦状细胞悬液和大鼠肝内皮细胞（LEC）的纯单层培养物含有并分泌可检测量的凝血因子。环己酰亚胺和莫能菌素可抑制培养的LEC分泌VIII:C。VIII:C至少在48小时内保持恒定水平，表明其是持续合成而非储存物质的爆发性释放。通过将X转化为Xa进行分光光度法测量，VIII:C受到抗人VIII:C抗血清的抑制。使用该抗血清进行间接免疫细胞化学检测，仅LEC呈现阳性染色。用抗人VIII:C抗血清对大鼠LEC条件培养基中代谢标记的蛋白质进行免疫沉淀，结果显示存在与报道的人VIII:C大小相似的蛋白质。这些结果表明，大鼠LEC是促凝血因子VIII产生和分泌的重要部位，而不仅仅是该因子储存和释放的部位。在体外培养的大鼠LEC中建立的VIII:C合成条件应为研究VIII:C合成的调控提供方法。
