Lehr H A, Olofsson A M, Carew T E, Vajkoczy P, von Andrian U H, Hübner C, Berndt M C, Steinberg D, Messmer K, Arfors K E
Institute for Surgical Research, University of Munich, Federal Republic of Germany.
Lab Invest. 1994 Sep;71(3):380-6.
Oxidized low density lipoprotein (oxLDL) has been demonstrated to stimulate leukocyte/endothelium interaction, an early feature of atherogenesis. Using the skinfold chamber model for intravital microscopy in hamsters and mice, we have shown that oxLDL-induced leukocyte adhesion to microvascular endothelium shares many characteristics with leukocyte adhesion during inflammation and ischemia/reperfusion, including the involvement of beta 2 integrin adhesion molecules. In light of the two-step model of leukocyte adhesion, we have examined the contribution of P-selectin to oxLDL-induced leukocyte/endothelium interaction. P-selectin is an inducible adhesion molecule on platelets and endothelium, mediating the initial steps of leukocyte margination and rolling along the endothelial lining, as well as of aggregate formation between platelets and leukocytes.
For our studies, we used the dorsal skinfold chamber model for intravital fluorescence microscopy on awake Syrian golden hamsters. Hamsters were treated 10 minutes before oxLDL-injection (oxidized by Cu2+, 4 mg/kg body weight, intravenously) with blocking antibodies to P-selectin (2 mg/kg body weight intravenously, N = 7).
In seven control animals (pretreated with an irrelevant IgG antibody), oxLDL injection elicited leukocyte rolling and adhesion on both venular and arteriolar endothelium, and also the formation of aggregates tumbling down the microvessels and firmly adhering to the microvascular endothelium. The aggregates consisted of leukocytes and activated, dendritic platelets, as assessed by scanning electron microscopy of the buffy coat isolated by density gradient centrifugation of whole blood taken from hamsters 15 minutes after injection of oxLDL. Leukocyte adhesion to venular and arteriolar endothelium, as well as the formation of leukocyte/platelet aggregates were significantly reduced by pretreatment of the animals with anti-P-selectin antibodies.
These data emphasize the similarities between leukocyte adhesion in response to oxLDL and in other pathophysiologic conditions, identifying P-selectin as a crucial player in the interaction between leukocytes and microvascular endothelium as well as in the formation of circulating leukocyte/platelet aggregates.
氧化型低密度脂蛋白（oxLDL）已被证明可刺激白细胞/内皮细胞相互作用，这是动脉粥样硬化形成的早期特征。利用仓鼠和小鼠的皮肤褶室模型进行活体显微镜观察，我们发现oxLDL诱导的白细胞与微血管内皮细胞的黏附与炎症和缺血/再灌注期间的白细胞黏附具有许多共同特征，包括β2整合素黏附分子的参与。根据白细胞黏附的两步模型，我们研究了P-选择素对oxLDL诱导的白细胞/内皮细胞相互作用的作用。P-选择素是血小板和内皮细胞上的一种诱导性黏附分子，介导白细胞沿内皮衬里边缘化和滚动的初始步骤，以及血小板与白细胞之间聚集体的形成。
在我们的研究中，我们使用背侧皮肤褶室模型对清醒的叙利亚金仓鼠进行活体荧光显微镜观察。在注射oxLDL（经Cu2+氧化，4mg/kg体重，静脉注射）前10分钟，用抗P-选择素阻断抗体（2mg/kg体重，静脉注射，N = 7）处理仓鼠。
在7只对照动物（用无关IgG抗体预处理）中，注射oxLDL后引起白细胞在小静脉和小动脉内皮上的滚动和黏附，以及聚集体在微血管中翻滚并牢固黏附于微血管内皮。通过对注射oxLDL 15分钟后从仓鼠采集的全血进行密度梯度离心分离的血沉棕黄层进行扫描电子显微镜观察评估，聚集体由白细胞和活化的树突状血小板组成。用抗P-选择素抗体预处理动物可显著减少白细胞与小静脉和小动脉内皮的黏附以及白细胞/血小板聚集体的形成。
这些数据强调了oxLDL诱导的白细胞黏附与其他病理生理条件下白细胞黏附之间的相似性，确定P-选择素是白细胞与微血管内皮细胞相互作用以及循环白细胞/血小板聚集体形成中的关键参与者。
