Bochenek Magdalena L, Rosinus Nico S, Lankeit Mareike, Hobohm Lukas, Bremmer Felix, Schütz Eva, Klok Frederikus A, Horke Sven, Wiedenroth Christoph B, Münzel Thomas, Lang Irene M, Mayer Eckhard, Konstantinides Stavros, Schäfer Katrin
Katrin Schäfer, MD FESC FAHA, Center for Cardiology, Cardiology I, University Medical Center Mainz, Langenbeckstrasse 1, D-55131 Mainz, Germany, Tel.: +49 6131 17 4221, E-mail:
Thromb Haemost. 2017 Apr 3;117(4):769-783. doi: 10.1160/TH16-10-0790. Epub 2017 Feb 2.
The pathomechanisms underlying the development of thrombofibrotic pulmonary artery occlusions in Chronic Thromboembolic Pulmonary Hypertension (CTEPH) are largely unknown. The aim of this study was to allocate distinct cellular processes playing a role in thrombus resolution, such as inflammation, hypoxia, proliferation, apoptosis and angiogenesis, to different stages of thrombofibrotic remodelling. A total of 182 pulmonary endarterectomy (PEA) specimens were collected from 31 CTEPH patients. To facilitate co-localisation, Tissue MicroArrays were prepared and processed for (immuno)-histochemistry and confocal fluorescence microscopy. Murine venous thrombus formation and resolution was examined after inferior vena cava ligation. PEA tissues exhibited five morphologically distinct regions predominantly consisting of either fibrin-, erythrocyte- or extracellular matrix-rich thrombus, myofibroblasts, vessels or fibrotic tissue, and were found to resemble chronological stages of thrombus resolution in mice. Cellularity was highest in vessel-rich regions, and numerous cells were strongly positive for HIF1α or HIF2α as well as markers of activated VEGF signalling, including endothelial nitric oxide synthase. On the other hand, negative regulators of angiogenic growth factor signalling and reactive oxygen species were also highly expressed. Immune cells, primarily macrophages of the M2 subtype and CD117 haematopoietic progenitors were detected and highest in vascularised regions. Our findings demonstrate the simultaneous presence of different stages of thrombus organisation and suggest that hypoxia-induced endothelial, mesenchymal and immune cell activation may contribute to thrombofibrosis in CTEPH. This systematic histological characterisation of the material obstructing pulmonary vessels in CTEPH may provide a valuable basis for further studies aimed at determining causal factors underlying this disease.
慢性血栓栓塞性肺动脉高压（CTEPH）中血栓纤维化性肺动脉闭塞形成的病理机制在很大程度上尚不清楚。本研究的目的是将在血栓溶解过程中起作用的不同细胞过程，如炎症、缺氧、增殖、凋亡和血管生成，与血栓纤维化重塑的不同阶段进行匹配。从31例CTEPH患者中收集了总共182份肺动脉内膜剥脱术（PEA）标本。为便于共定位，制备了组织微阵列并进行（免疫）组织化学和共聚焦荧光显微镜检查。在结扎下腔静脉后检查小鼠静脉血栓的形成和溶解。PEA组织表现出五个形态学上不同的区域，主要由富含纤维蛋白、红细胞或细胞外基质的血栓、肌成纤维细胞、血管或纤维化组织组成，并且发现类似于小鼠血栓溶解的时间阶段。富含血管的区域细胞密度最高，许多细胞对HIF1α或HIF2α以及活化的VEGF信号标志物（包括内皮型一氧化氮合酶）呈强阳性。另一方面，血管生成生长因子信号的负调节因子和活性氧也高表达。检测到免疫细胞，主要是M2亚型巨噬细胞和CD117造血祖细胞，在血管化区域中含量最高。我们的研究结果表明血栓组织化的不同阶段同时存在，并提示缺氧诱导的内皮细胞、间充质细胞和免疫细胞活化可能导致CTEPH中的血栓纤维化。这种对CTEPH中阻塞肺血管物质的系统组织学特征描述可能为进一步研究该疾病的因果因素提供有价值的基础。
