Abstract：
BACKGROUND: During human morphogenesis, the definitive kidneys derive from the metanephros during Carnegie Stage 14 to 23. The pronephros and the mesonephros develop previously and successively to finally lead to the formation of the urinary tract. Renal vascularization, first described in 1912 by Félix using a \"ladder theory\" model, is highly variable and current available morphogenesis descriptions do not explain all reported anatomical variations. The aim of this work was to study the morphogenesis of the human metanephros and its vascularization by three-dimensional reconstructions of human embryos.
METHODS: Histological sections of 23 human embryos from the Carnegie Collection and 5 human embryos from the French collection (Carnegie stages 14 to 23) were completely digitalized and reconstructed in three dimensions using specific softwares and then analyzed by descriptive method using manual annotation.
RESULTS: In all studied embryos, the mesonephric arteries did not reach the metanephros irrespective to the position of the metanephros during its cranial ascent. Before the end of the cranial metanephros migration (15 embryos), at the level of the aorto-iliac bifurcation, a \"primitive\" vascularization was shown in 9 of them. The renal artery originated from the primitive iliac arteries for 8 embryos and from the inferior mesenteric artery in one embryo. Further, a capillary cluster emerging from the lateral wall of the aorta and extending toward the metanephros was found in 2 embryos (Carnegie stages 21 and 22). This may correspond to a phenomenon of neoangiogenesis responsible of the definitive renal artery.
CONCLUSIONS: The present study reported the morphogenesis of human renal arteries between Carnegie stages 14 and 23 using an original method of tridimensional computerized reconstructions of historical human embryos. Some original findings, in contradiction with the original Felix\'s description, may explain the most frequently reported anatomical variations.
METHODS: Histological sections of 23 human embryos from the Carnegie Collection and 5 human embryos from the French collection (Carnegie stages 14 to 23) were completely digitalized and reconstructed in three dimensions using specific softwares and then analyzed by descriptive method using manual annotation.
RESULTS: In all studied embryos, the mesonephric arteries did not reach the metanephros irrespective to the position of the metanephros during its cranial ascent. Before the end of the cranial metanephros migration (15 embryos), at the level of the aorto-iliac bifurcation, a \"primitive\" vascularization was shown in 9 of them. The renal artery originated from the primitive iliac arteries for 8 embryos and from the inferior mesenteric artery in one embryo. Further, a capillary cluster emerging from the lateral wall of the aorta and extending toward the metanephros was found in 2 embryos (Carnegie stages 21 and 22). This may correspond to a phenomenon of neoangiogenesis responsible of the definitive renal artery.
CONCLUSIONS: The present study reported the morphogenesis of human renal arteries between Carnegie stages 14 and 23 using an original method of tridimensional computerized reconstructions of historical human embryos. Some original findings, in contradiction with the original Felix\'s description, may explain the most frequently reported anatomical variations.
摘要：
目标：在人类形态发生过程中，确定的肾脏来自卡内基14至23期的后肾。pronephros和中肾先前和相继发展，最终导致尿路的形成。肾血管化,费利克斯于1912年首次使用“阶梯理论”模型进行描述，是高度可变的，目前可用的形态发生描述不能解释所有报道的解剖变异。这项工作的目的是通过人类胚胎的三维重建研究人类后肾的形态发生及其血管形成。
方法：将卡内基馆藏的23个人类胚胎和法国馆藏的5个人类胚胎（卡内基14至23期）的组织学切片完全数字化并使用特定软件进行三维重建，然后通过描述性方法使用手动注释进行分析。
结果：在所有研究的胚胎中，无论后肾在颅骨上升过程中的位置如何，中肾动脉均未到达后肾。在颅后肾迁移结束之前（15个胚胎），在主动脉-髂分叉处,其中9例显示了“原始”血管化。肾动脉起源于8个胚胎的原始髂动脉和一个胚胎的肠系膜下动脉。Further,在2个胚胎（卡内基21期和22期）中发现了从主动脉侧壁出现并向后肾延伸的毛细血管簇。这可能对应于由确定的肾动脉负责的新血管生成现象。
结论：本研究报告了卡内基14和23期之间的人类肾动脉的形态发生，使用一种原始的方法对历史人类胚胎进行三维计算机重建。一些原始发现，与费利克斯的原始描述相矛盾，可以解释最常报告的解剖变异。
方法：将卡内基馆藏的23个人类胚胎和法国馆藏的5个人类胚胎（卡内基14至23期）的组织学切片完全数字化并使用特定软件进行三维重建，然后通过描述性方法使用手动注释进行分析。
结果：在所有研究的胚胎中，无论后肾在颅骨上升过程中的位置如何，中肾动脉均未到达后肾。在颅后肾迁移结束之前（15个胚胎），在主动脉-髂分叉处,其中9例显示了“原始”血管化。肾动脉起源于8个胚胎的原始髂动脉和一个胚胎的肠系膜下动脉。Further,在2个胚胎（卡内基21期和22期）中发现了从主动脉侧壁出现并向后肾延伸的毛细血管簇。这可能对应于由确定的肾动脉负责的新血管生成现象。
结论：本研究报告了卡内基14和23期之间的人类肾动脉的形态发生，使用一种原始的方法对历史人类胚胎进行三维计算机重建。一些原始发现，与费利克斯的原始描述相矛盾，可以解释最常报告的解剖变异。
