Cobellis L, De Falco M, Mastrogiacomo A, Giraldi D, Dattilo D, Scaffa C, Colacurci N, De Luca A
Department of Obstetrics and Gynecology, Second University of Naples, Naples, Italy.
Histol Histopathol. 2007 Jan;22(1):1-8. doi: 10.14670/HH-22.1.
Apelin is an endogenous ligand of the human orphan receptor APJ. This peptide is produced through processing from the C-terminal portion in the pre-pro-protein consisting of 77 amino acid residues and exists in multiple molecular forms. Although the main physiological functions of apelin have not yet been clarified, it is known that apelin is involved in the regulation of blood pressure, blood flow and central control of body fluid homeostasis in different organs. Since human placenta is a tissue where vasculogenesis, blood pressure and flow are dramatically important to allow a normal embryonic and fetal growth and development, the aim of the present study was to investigate the immunohistochemical distribution of apelin and APJ in normal placentas throughout pregnancy and in preeclampsia-complicated placentas. Specifically, we observed that in normal placentas the expression levels of apelin decreased from the first to the third trimester of gestation in both cytotrophoblast and syncytiotrophoblast cells and in the stroma of placental villi, in contrast with increased expression levels of APJ in the cytoplasm of cytotrophoblast cells and in the cytoplasm of endothelial cells of normal placenta samples. In contrast, in preeclampsia-complicated pregnancies, we observed a very strong increase of expression levels of both apelin and APJ receptor in all the placental compartments, cytotrophoblast, syncytiotrophoblast and stroma with a particular increase in endothelial cells inside preeclamptic placental villi. Our data seem to indicate an important role of apelin and APJ in the regulation of fetal development through a correct regulation of human placenta formation during pregnancy. Moreover, the strong expression levels of apelin and APJ in preeclamptic placentas, suggest their possible involvement in the onset of this pathology.
Apelin是人类孤儿受体APJ的内源性配体。该肽由77个氨基酸残基组成的前体蛋白的C末端部分加工而成，并以多种分子形式存在。尽管Apelin的主要生理功能尚未阐明，但已知Apelin参与不同器官的血压、血流调节以及体液稳态的中枢控制。由于人类胎盘是血管生成、血压和血流对正常胚胎和胎儿生长发育至关重要的组织，本研究的目的是调查Apelin和APJ在整个孕期正常胎盘以及子痫前期合并胎盘的免疫组织化学分布。具体而言，我们观察到在正常胎盘的细胞滋养层细胞、合体滋养层细胞以及胎盘绒毛基质中，Apelin的表达水平从妊娠第一期到第三期逐渐降低，而在正常胎盘样本的细胞滋养层细胞胞质和内皮细胞胞质中，APJ的表达水平则升高。相比之下，在子痫前期合并妊娠中，我们观察到在所有胎盘区室（细胞滋养层、合体滋养层和基质）中，Apelin和APJ受体的表达水平均显著升高，子痫前期胎盘绒毛内的内皮细胞中升高尤为明显。我们的数据似乎表明，Apelin和APJ在孕期通过正确调节人类胎盘形成对胎儿发育的调节中发挥重要作用。此外，Apelin和APJ在子痫前期胎盘中的高表达水平表明它们可能参与了这种病理状态的发生。
