Department of Histology and Cell Pathology, FMS in Zabrze, Medical University of Silesia, Katowice, Poland.
Department of Electrocardiology, Medical University of Łodź, Łodź, Poland.
Folia Histochem Cytobiol. 2021;59(4):212-225. doi: 10.5603/FHC.a2021.0027. Epub 2021 Dec 8.
Cardiac papillary fibroelastomas (CPFs) are rare benign cardiac tumors typically found on the heart valves. The previously published data on the CPF focused on its clinical presentation, optimal management, and prognosis. However, histogenesis of these lesions remains controversial. Accordingly, the aim of this study was to establish the role of endocardial endothelium (EE) in CPF formation.
Four CPF tumors removed from the right atrioventricular valves were analyzed using hematoxylin & eosin, orcein, and Masson trichrome staining together with immunochemistry for CD-34, CD-68, vimentin, vWF and a-SMA. Moreover, conventional transmission electron microscopy was used for morphological analysis and a-SMA presence confirmation.
Ultrastructural morphology, immunohisto- and immunocytochemical analyses indicated that cells covering collagenous core have an endothelial origin. Some endocardial endothelium cells have the potential to undergo a transition to mesenchymal cells. Moreover, the abundant presence of extracellular vesicles may indicate an active intercellular communication. Within the intermediate translucent zone, amorphous substances with monocytes/macrophage-like cells and fibroblastic cells were found. Finally, within collagenous core activated (myo)fibroblasts were observed.
Our study demonstrated that the endocardial endothelium of the CPF was "double-sided", i.e., it presented both endothelial and mesenchymal cell characteristics. Another finding was the presence of monocytes, and macrophages which were integrated into CPF core and displayed features of a fibroblast that have been shown to contribute to extracellular matrix production. This could be interpreted as being attributed to the CPF histogenesis.
心脏乳头状纤维弹性瘤（CPF）是一种罕见的良性心脏肿瘤，通常发生在心脏瓣膜上。之前发表的数据主要集中在 CPF 的临床表现、最佳治疗方法和预后上。然而，这些病变的组织发生仍存在争议。因此，本研究旨在确定心内膜内皮细胞（EE）在 CPF 形成中的作用。
对取自右房室瓣的 4 个 CPF 肿瘤进行苏木精-伊红、奥氏染色和 Masson 三色染色，并进行 CD-34、CD-68、波形蛋白、vWF 和 a-SMA 的免疫化学染色。此外，还使用常规透射电子显微镜进行形态学分析和 a-SMA 存在的确认。
超微结构形态学、免疫组织化学和免疫细胞化学分析表明，覆盖胶原核心的细胞具有内皮细胞起源。一些心内膜内皮细胞具有向间充质细胞转化的潜力。此外，大量细胞外囊泡的存在可能表明存在活跃的细胞间通讯。在中间半透明区，发现了具有单核细胞/巨噬细胞样细胞和纤维母细胞特征的无定形物质。最后，在胶原核心中观察到激活的（肌）成纤维细胞。
本研究表明，CPF 的心内膜内皮细胞是“双面的”，即同时具有内皮细胞和间充质细胞的特征。另一个发现是单核细胞和巨噬细胞的存在，它们整合到 CPF 核心中，并表现出纤维母细胞的特征，这些特征已被证明有助于细胞外基质的产生。这可以解释为 CPF 的组织发生。
