Wiggins R, Glatfelter A, Kshirsagar B, Beals T
Lab Invest. 1987 Mar;56(3):264-72.
The procoagulant activity (PCA) in urine of rabbits with nephrotoxic nephritis was characterized. Most of the PCA in urine was pelleted by centrifugation at 50,000 X g but was not pelleted together with cells and casts at 1,000 X g. PCA appeared in the void volume of a Sepharose 4B column but would not pass through a 0.2-micron filter. Ultrastructural studies using both transmission and scanning electron microscopy showed that urine PCA was associated with lipid vesicles 0.1 to 1-micron in diameter. These vesicular structures were shown to promote fibrin formation from recalcified plasma on a 0.2-micron filter surface. This microvesicular PCA was mostly Factor VII-like as judged by clotting assay using human factor-deficient plasmas. Aggregates of vesicles were present in urine as granular casts. Ultrastructural studies of rabbit kidney showed similar vesicular structures in the proximal tubular lumen and budding from glomerular epithelial cells. Fibrin was seen adjacent to both glomerular endothelial cells and epithelial cells in association with vesicular structures. We conclude that microvesicles in urine carry a procoagulant signal which is tissue factor/Factor VII-like. We speculate that these vesicles may come from the glomerulus by budding off from glomerular epithelial cells, or macrophages.
对患有肾毒性肾炎的兔子尿液中的促凝血活性（PCA）进行了表征。尿液中的大部分PCA在50,000×g离心时被沉淀，但在1,000×g时不会与细胞和管型一起沉淀。PCA出现在琼脂糖4B柱的空体积中，但不会通过0.2微米的过滤器。使用透射电子显微镜和扫描电子显微镜的超微结构研究表明，尿液PCA与直径为0.1至1微米的脂质囊泡相关。这些囊泡结构被证明可促进在0.2微米过滤器表面上从重新钙化的血浆中形成纤维蛋白。通过使用人因子缺陷血浆的凝血测定判断，这种微囊泡PCA大多类似因子VII。囊泡聚集体以颗粒管型的形式存在于尿液中。对兔肾的超微结构研究表明，在近端肾小管腔中以及从肾小球上皮细胞出芽处存在类似的囊泡结构。在与囊泡结构相关的肾小球内皮细胞和上皮细胞附近均可见到纤维蛋白。我们得出结论，尿液中的微囊泡携带一种类似组织因子/因子VII的促凝血信号。我们推测这些囊泡可能通过从肾小球上皮细胞或巨噬细胞出芽而来自肾小球。
