Kidney organoids are regarded as important tools with which to study the development of the normal and diseased human kidney. Since the first reports of human pluripotent stem cell-derived kidney organoids 5 years ago, kidney organoids have been successfully used to model glomerular and tubular diseases. In parallel, advances in single-cell RNA sequencing have led to identification of a variety of cell types in the organoids, and have shown these to be similar to, but more immature than, human kidney cells in vivo. Protocols for the in vitro expansion of stem cell-derived nephron progenitor cells (NPCs), as well as those for the selective induction of specific lineages, especially glomerular podocytes, have also been reported. Although most current organoids are based on the induction of NPCs, an induction protocol for ureteric buds (collecting duct precursors) has also been developed, and approaches to generate more complex kidney structures may soon be possible. Maturation of organoids is a major challenge, and more detailed analysis of the developing kidney at a single cell level is needed. Eventually, organotypic kidney structures equipped with nephrons, collecting ducts, ureters, stroma and vascular flow are required to generate transplantable kidneys; such attempts are in progress.

中文翻译：

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人肾类器官：进步和尚存的挑战。

肾脏类器官被认为是研究正常和患病人类肾脏发育的重要工具。自5年前首次报道人类多能干细胞衍生的肾脏类器官以来，肾脏类器官已成功用于模拟肾小球和肾小管疾病。同时，单细胞RNA测序技术的进步已导致类器官中多种细胞类型的鉴定，并显示它们与体内人肾细胞相似但不成熟。还已经报道了用于体外扩增干细胞来源的肾单位祖细胞（NPC）的方案，以及用于选择性诱导特定谱系（尤其是肾小球足细胞）的方案。尽管目前大多数类器官都基于NPC的诱导，还已经开发出一种针对输尿管芽（收集导管前体）的诱导方案，不久可能会产生产生更复杂的肾脏结构的方法。类器官的成熟是一个重大挑战，需要在单个细胞水平上对发育中的肾脏进行更详细的分析。最终，需要配备肾单位，收集管，输尿管，基质和血管血流的器官型肾脏结构才能产生可​​移植的肾脏。这样的尝试正在进行中。需要基质和血管血流才能产生可​​移植的肾脏；这样的尝试正在进行中。需要基质和血管血流才能产生可​​移植的肾脏；这样的尝试正在进行中。