Lai John C K, Tranfield Erin M, Walker David C, Dyck Jennifer, Kerjner Alexandra, Loo Sylvia, English Dean, Wong Donald, McDonald Paul C, Moghadasian Mohammed H, Wilson Janet E, McManus Bruce M
University of British Columbia McDonald Research Laboratories, iCAPTUR4E Centre, Department of Pathology and Laboratory Medicine, St. Paul's Hospital, Providence Health Care, Vancouver, British Columbia, Canada.
J Heart Lung Transplant. 2003 Sep;22(9):993-1004. doi: 10.1016/s1053-2498(02)01163-4.
Events that occur early after transplantation, particularly immune recognition of allo-endothelium, initiate transplant vascular disease (TVD). Previous work suggests an important compromise of endothelial integrity as the allo-immune milieu evolves, although mechanisms by which integrity is altered remain unclear. Increased vascular permeability caused by endothelial damage may allow inflammatory cells, lipoproteins, other proteins, and plasma fluid to enter the sub-endothelial space, thereby contributing to the initiation of atherosclerosis. In this study, we examined endothelial integrity in coronary arteries and the proximal aorta after cardiac transplantation in rats.
We used Lewis-to-Lewis and Lewis-to-F344 rat heterotopic cardiac transplant models. We studied the effects of cyclosporine (5mg/kg/day) therapy compared with saline-treated controls. En face silver nitrate staining was performed to demonstrate endothelial cell borders and gaps. We used scanning electron microscopy to extend silver nitrate findings and to further define the presence and nature of endothelial disruptions. We used transmission electron microscopy to further characterize immune cell identity and interaction with endothelium.
Syngrafts and cyclosporine-treated allografts showed normal-looking endothelium similar to that observed in arteries from native hearts. However, saline-treated allografts displayed progressive endothelial destruction, including large intercellular gaps, missing cells, and areas of bare extracellular matrix. Exfoliated surfaces were covered by platelets at various stages of adhesion, activation, and spreading. Similarly, we observed numerous leukocytes as either adherent to the endothelial lining or transmigrating into the sub-endothelial space. Cessation of cyclosporine therapy was associated with the development of similar abnormalities.
Our findings indicate that, especially when immunosuppression is insufficient, early endothelial damage may promote vascular permeability and thereby initiate TVD.
移植后早期发生的事件，尤其是对同种异体内皮的免疫识别，会引发移植血管病（TVD）。先前的研究表明，随着同种异体免疫环境的演变，内皮完整性会受到重要损害，尽管完整性改变的机制仍不清楚。内皮损伤导致的血管通透性增加可能会使炎性细胞、脂蛋白、其他蛋白质和血浆进入内皮下间隙，从而促进动脉粥样硬化的发生。在本研究中，我们检测了大鼠心脏移植后冠状动脉和主动脉近端的内皮完整性。
我们使用了Lewis-to-Lewis和Lewis-to-F344大鼠异位心脏移植模型。我们研究了环孢素（5mg/kg/天）治疗与生理盐水处理对照组相比的效果。进行硝酸银表面染色以显示内皮细胞边界和间隙。我们使用扫描电子显微镜扩展硝酸银染色的结果，并进一步确定内皮破坏的存在和性质。我们使用透射电子显微镜进一步表征免疫细胞的特征以及与内皮的相互作用。
同基因移植组和环孢素处理的异基因移植组显示内皮外观正常，类似于天然心脏动脉中的内皮。然而，生理盐水处理的异基因移植组显示内皮逐渐破坏，包括大的细胞间隙、细胞缺失以及裸露的细胞外基质区域。脱落的表面被处于不同黏附、激活和铺展阶段的血小板覆盖。同样，我们观察到大量白细胞要么黏附在内皮表面，要么迁移到内皮下间隙。停止环孢素治疗与类似异常的发生有关。
我们的研究结果表明，尤其是在免疫抑制不足时，早期内皮损伤可能会促进血管通透性增加，从而引发TVD。
