Institut für Biochemie, Westfälische Wilhelms-Universität Münster, Wilhelm-Klemm-Straße 2, D-48149 Münster, Germany.
Brain Res. 2011 Jan 7;1367:62-76. doi: 10.1016/j.brainres.2010.09.076. Epub 2010 Sep 25.
The cerebral microcapillary endothelium forms a highly important barrier between the blood and the interstitial fluid of the brain (blood-brain barrier) that controls the passage of molecules and cells in and out of the CNS. Several CNS diseases include leukocyte extravasation through the endothelium via two mechanistically distinct routes, the paracellular and the transcellular pathway. We established a new in vitro model of the inflamed blood-brain barrier consisting of primary cultured porcine brain capillary endothelial cells which express a tight endothelial barrier even under inflammatory conditions. By means of this specialized blood-brain barrier model we extensively studied the transmigration of neutrophils. Electron and scanning force microscopy as well as immunofluorescence imaging captured the penetrating neutrophil on the endothelial cellular body in between the junctions clearly suggesting a transcellular migration pathway. Electric cell-substrate impedance sensing and transendothelial electrical resistance measurements in combination with expression analysis of tight junction proteins demonstrate that the neutrophil-endothelial interaction does not disrupt the barrier. In conclusion, this study, based on an in vitro model of the blood-brain barrier under inflammatory conditions, evidently implicates that neutrophils preferentially migrate across the BBB via the transcellular route without impairing endothelial barrier function whereas paracellular transmigration plays only a minor role if the barrier is strongly expressed.
脑毛细血管内皮细胞在血液和脑间质液（血脑屏障）之间形成了一个非常重要的屏障，控制着中枢神经系统内外分子和细胞的通过。几种中枢神经系统疾病包括白细胞通过内皮细胞的两种不同机制的细胞外渗，即细胞旁途径和细胞内途径。我们建立了一种新的体外炎症性血脑屏障模型，由原代培养的猪脑毛细血管内皮细胞组成，即使在炎症条件下，这些内皮细胞也表达出紧密的内皮屏障。通过这种特殊的血脑屏障模型，我们广泛研究了中性粒细胞的迁移。电子和扫描力显微镜以及免疫荧光成像清楚地捕捉到了在连接点之间穿透内皮细胞体的中性粒细胞，这表明存在细胞内迁移途径。细胞-基底阻抗传感和跨内皮电阻测量以及紧密连接蛋白的表达分析表明，中性粒细胞-内皮细胞相互作用不会破坏屏障。总之，这项基于炎症条件下血脑屏障体外模型的研究表明，中性粒细胞优先通过细胞内途径穿过 BBB，而不会损害内皮屏障功能，而细胞旁迁移只有在屏障强烈表达时才起次要作用。
