Cell therapy, i.e., the use of cells to repair an affected tissue or organ, is at the forefront of regenerative and personalized medicine. Among the multiple cell types that have been used for this purpose [including adult stem cells such as mesenchymal stem cells or pluripotent stem cells], urine-derived stem cells (USCs) have aroused interest in the past years. USCs display classical features of mesenchymal stem cells such as differentiation capacity and immunomodulation. Importantly, they have the main advantage of being isolable from one sample of voided urine with a cheap and unpainful procedure, which is broadly applicable, whereas most adult stem cell types require invasive procedure. Moreover, USCs can be differentiated into renal cell types. This is of high interest for renal cell therapy-based regenerative approaches. This review will firstly describe the isolation and characterization of USCs. We will specifically present USC phenotype, which is not an object of consensus in the literature, as well as detail their differentiation capacity. In the second part of this review, we will present and discuss the main applications of USCs. These include use as a substrate to generate human induced pluripotent stem cells, but we will deeply focus on the use of USCs for cell therapy approaches with a detailed analysis depending on the targeted organ or system. Importantly, we will also focus on the applications that rely on the use of USC-derived products such as microvesicles including exosomes, which is a strategy being increasingly employed. In the last section, we will discuss the remaining barriers and challenges in the field of USC-based regenerative medicine.

中文翻译：

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尿液来源的干/祖细胞：专注于其表征和潜力。

细胞疗法，即使用细胞修复受影响的组织或器官是再生和个性化医学的最前沿。在过去已用于此目的的多种细胞类型中（包括间充质干细胞或多能干细胞等成年干细胞），尿液衍生干细胞（USC）引起了人们的兴趣。USC显示间充质干细胞的经典功能，例如分化能力和免疫调节。重要的是，它们的主要优点是可以通过廉价且无痛的操作从一个尿液样本中分离出该样品，该方法广泛适用，而大多数成年干细胞类型都需要侵入性操作。此外，USC可以区分为肾细胞类型。这对于基于肾细胞疗法的再生方法非常感兴趣。本文将首先描述USC的隔离和特性。我们将具体介绍USC表型，并详细说明其分化能力，这不是文献中达成共识的对象。在本文的第二部分，我们将介绍和讨论USC的主要应用。这些方法包括用作产生人诱导的多能干细胞的底物，但我们将深入关注USC在细胞治疗方法中的应用，并根据目标器官或系统进行详细分析。重要的是，我们还将专注于依赖于USC衍生产品（例如包括囊泡在内的微囊泡）使用的应用，这是一种越来越多地采用的策略。在上一节中，我们将讨论基于USC的再生医学领域中尚存的障碍和挑战。