Fritsch Helga, Aigner Felix, Ludwikowski Barbara, Reinstadler-Zankl Sandra, Illig Romana, Urbas Dieter, Schwarzer Christoph, Longato Stefano
Department of Anatomy, Histology, and Embryology, Division of Clinical and Functional Anatomy, Medical University of Innsbruck, Innsbruck, Austria.
Anat Rec (Hoboken). 2007 Nov;290(11):1449-58. doi: 10.1002/ar.20589.
In the past, interpretations of anorectal development were mainly based on analysis of serially sectioned embryos of various nonhuman species as well as some human specimens. A four-dimensional view of the developmental situation in the human has never been established nor connected to recent findings obtained from newer molecular techniques. We, therefore, investigated human embryonic and fetal pelves by means of immunohistochemistry and in situ hybridization to elucidate differentiation and interaction of epithelial and mesenchymal layers of the anorectum. To emphasize spatial as well as sequential morphological development, we produced three-dimensional reconstructions of the specimens at hand. Research conducted proved that the decisive steps of epithelial and muscular differentiation occur between the 7th and 9th week after conception. This study elucidates a biphasic epithelial "closure" in the anal canal and interactions between epithelium, smooth musculature, and skeletal musculature. Based on the results presented here, it is possible to describe the pathogenesis of two anorectal malformations: the imperforate anal membrane and the anal membrane stenosis. This study will now provide the basis for further research into developmental processes occurring before the ones examined.
过去，对肛门直肠发育的解释主要基于对各种非人类物种以及一些人类标本的连续切片胚胎的分析。从未建立过人类发育情况的四维视图，也未将其与从更新的分子技术获得的最新发现联系起来。因此，我们通过免疫组织化学和原位杂交研究了人类胚胎和胎儿骨盆，以阐明肛门直肠上皮和间充质层的分化及相互作用。为强调空间以及连续的形态发育，我们对现有标本进行了三维重建。进行的研究证明，上皮和肌肉分化的决定性步骤发生在受孕后第7至9周之间。本研究阐明了肛管上皮的双相“闭合”以及上皮、平滑肌和骨骼肌之间的相互作用。基于此处给出的结果，可以描述两种肛门直肠畸形的发病机制：肛门膜闭锁和肛门膜狭窄。本研究现在将为进一步研究在所检查的发育过程之前发生的发育过程提供基础。
