The connecting tubule (CNT) is a unique segment of the nephron connecting the metanephric mesenchyme (MM)-derived distal convoluted tubule (DCT) and ureteric bud (UB)-derived collecting duct (CD). Views on the cellular origin of the CNT in the human kidney are controversial. It was suggested that in mice, the connecting segment arises from the distal compartment of the renal vesicle (RV). However, there are several differences in embryonic development between the mouse and human kidney. The aim of our study was to establish the possible origin of the CNT in the human kidney. We analysed the expression of markers defining distinct cells of the CNT CD in foetal and adult human kidneys by immunohistochemistry. Based on microscopic observation, we suggest that CNT differentiates from the outgrowth of cells of the UB tip, and therefore the CNT is an integral part of the CD system. In the adult kidney, the CNT and CD consist of functionally and morphologically similar cells expressing α- and β-intercalated cell (IC) and principal cell (PC) markers, indicating their common origin.

连接小管 (CNT) 是肾单位的独特部分，连接后肾间充质 (MM) 衍生的远曲小管 (DCT) 和输尿管芽 (UB) 衍生的集合管 (CD)。关于人肾脏中 CNT 的细胞起源的观点是有争议的。有人提出，在小鼠中，连接段来自肾囊泡 (RV) 的远端隔室。然而，小鼠和人类肾脏之间的胚胎发育存在一些差异。我们研究的目的是确定 CNT 在人体肾脏中的可能来源。我们通过免疫组织化学分析了定义胎儿和成人肾脏中 CNT CD 不同细胞的标志物的表达。基于显微镜观察，我们认为 CNT 与 UB 尖端细胞的产物不同，因此，CNT 是 CD 系统的一个组成部分。在成人肾脏中，CNT 和 CD 由功能和形态相似的细胞组成，表达 α 和 β 闰细胞 (IC) 和主细胞 (PC) 标记，表明它们的共同起源。