Böhm Elsa Wilma, Pavlaki Maria, Chalikias Georgios, Mikroulis Dimitrios, Georgiadis George S, Tziakas Dimitrios N, Konstantinides Stavros, Schäfer Katrin
Department of Cardiology, University Medical Center, Mainz, Germany.
Department of Cardiology, Democritus University of Thrace, Alexandroupolis, Greece.
TH Open. 2021 Apr 14;5(2):e113-e124. doi: 10.1055/s-0041-1725042. eCollection 2021 Apr.
Intimal calcification typically develops in advanced atherosclerosis, and microcalcification may promote plaque progression and instability. Conversely, intraplaque hemorrhage and erythrocyte extravasation may stimulate osteoblastic differentiation and intralesional calcium phosphate deposition. The presence of erythrocytes and their main cellular components (membranes, hemoglobin, and iron) and colocalization with calcification has never been systematically studied. We examined three types of diseased vascular tissue specimens, namely, degenerative aortic valve stenosis ( = 46), atherosclerotic carotid artery plaques ( = 9), and abdominal aortic aneurysms ( = 14). Biomaterial was obtained from symptomatic patients undergoing elective aortic valve replacement, carotid artery endatherectomy, or aortic aneurysm repair, respectively. Serial sections were stained using Masson-Goldner trichrome, Alizarin red S, and Perl's iron stain to visualize erythrocytes, extracelluar matrix and osteoid, calcium phosphate deposition, or the presence of iron and hemosiderin, respectively. Immunohistochemistry was employed to detect erythrocyte membranes (CD235a), hemoglobin or the hemoglobin scavenger receptor (CD163), endothelial cells (CD31), myofibroblasts (SMA), mesenchymal cells (osteopontin), or osteoblasts (periostin). Our analyses revealed a varying degree of intraplaque hemorrhage and that the majority of extravasated erythrocytes were lysed. Osteoid and calcifications also were frequently present, and erythrocyte membranes were significantly more prevalent in areas with calcification. Areas with extravasated erythrocytes frequently contained CD163-positive cells, although calcification also occurred in areas without CD163 immunosignals. Our findings underline the presence of extravasated erythrocytes and their membranes in different types of vascular lesions, and their association with areas of calcification suggests an active role of erythrocytes in vascular disease processes.
内膜钙化通常在晚期动脉粥样硬化中发展，而微钙化可能促进斑块进展和不稳定。相反，斑块内出血和红细胞外渗可能刺激成骨细胞分化和病灶内磷酸钙沉积。红细胞及其主要细胞成分（膜、血红蛋白和铁）的存在以及与钙化的共定位从未得到系统研究。
我们检查了三种类型的病变血管组织标本，即退行性主动脉瓣狭窄（n = 46）、动脉粥样硬化性颈动脉斑块（n = 9）和腹主动脉瘤（n = 14）。生物材料分别取自接受择期主动脉瓣置换术、颈动脉内膜切除术或主动脉瘤修复术的有症状患者。连续切片分别用Masson-Goldner三色染色、茜素红S染色和Perl铁染色，以分别观察红细胞、细胞外基质和类骨质、磷酸钙沉积或铁和含铁血黄素的存在。采用免疫组织化学检测红细胞膜（CD235a）、血红蛋白或血红蛋白清除受体（CD163）、内皮细胞（CD31）、肌成纤维细胞（SMA）、间充质细胞（骨桥蛋白）或成骨细胞（骨膜蛋白）。我们的分析显示斑块内出血程度不同，大多数外渗红细胞被溶解。类骨质和钙化也经常出现，红细胞膜在钙化区域明显更普遍。外渗红细胞的区域经常含有CD163阳性细胞，尽管钙化也发生在没有CD163免疫信号的区域。
我们的研究结果强调了不同类型血管病变中存在外渗红细胞及其膜，它们与钙化区域的关联表明红细胞在血管疾病过程中发挥了积极作用。
