Vrancken Peeters M P, Gittenberger-de Groot A C, Mentink M M, Poelmann R E
Department of Anatomy and Embryology, Leiden University Medical Center, The Netherlands.
Anat Embryol (Berl). 1999 Apr;199(4):367-78. doi: 10.1007/s004290050235.
Previous research has revealed that cells contributing to coronary vascular formation are derived from the dorsal mesocardium, however, the fate of these cells during consecutive stages of heart development is still unclear. We have conducted a study regarding the recruitment of vascular components and the subsequent differentiation into mature vessel wall structures with the aid of immunohistochemical markers directed against endothelium, smooth muscle cells, and fibroblasts. The proepicardial organ including an adhering piece of primordial liver of quail embryos (ranging from HH15 to HH18) was transplanted into the pericardial cavity of chicken embryos (ranging from HH15 to HH18). The chicken-quail chimeras (n=16) were harvested from the early stage of endothelial tube formation (HH25) to the late stage of mature vessel wall composition (HH43). Before HH32 endothelial cells have invaded the myocardium to give rise to yet undifferentiated coronary vessels. These endothelial cells are not accompanied by other non-endothelial cells. The superficial epicardial layer changes from a squamous mesothelium into a cuboid epithelium preceding media and adventitia formation. Subsequently, a condensed area of mesenchymal cells delaminates from the cuboidal lining extending toward the vessel plexus. Around the coronary arteries, these mesenchymal cells differentiate into smooth muscle cells or fibroblasts as shown by immunohistochemical markers. We conclude that epithelial-mesenchymal transformation of the epicardial lining delivers the smooth muscle cells and fibroblasts of the coronary arterial vessel wall. Molecules involved in epithelial transformation processes elsewhere in the embryo are also expressed within the subepicardial layer, and are considered to participate in inducing this process.
先前的研究表明，参与冠状动脉形成的细胞源自背侧心内膜，然而，这些细胞在心脏发育连续阶段的命运仍不清楚。我们借助针对内皮细胞、平滑肌细胞和成纤维细胞的免疫组织化学标记物，开展了一项关于血管成分募集以及随后分化为成熟血管壁结构的研究。将包含鹌鹑胚胎原始肝脏附着部分（HH15至HH18）的前心外膜器官移植到鸡胚胎（HH15至HH18）的心包腔内。鸡 - 鹌鹑嵌合体（n = 16）从内皮管形成早期（HH25）收获至成熟血管壁组成后期（HH43）。在HH32之前，内皮细胞侵入心肌以形成未分化的冠状动脉。这些内皮细胞没有其他非内皮细胞伴随。在心外膜和外膜形成之前，浅表心外膜层从鳞状间皮转变为立方上皮。随后，间充质细胞浓缩区域从立方衬里分层，向血管丛延伸。如免疫组织化学标记所示，在冠状动脉周围，这些间充质细胞分化为平滑肌细胞或成纤维细胞。我们得出结论，心外膜衬里的上皮 - 间充质转化产生了冠状动脉血管壁的平滑肌细胞和成纤维细胞。在胚胎其他部位参与上皮转化过程的分子也在心外膜下层表达，并被认为参与诱导这一过程。
