Urine is a valuable diagnostic medium and, with the discovery of urinary extracellular vesicles, is viewed as a dynamic bioactive fluid. Extracellular vesicles are lipid-enclosed structures that can be classified into three categories: exosomes, microvesicles (or ectosomes) and apoptotic bodies. This classification is based on the mechanisms by which membrane vesicles are formed: fusion of multivesicular bodies with the plasma membranes (exosomes), budding of vesicles directly from the plasma membrane (microvesicles) or those shed from dying cells (apoptotic bodies). During their formation, urinary extracellular vesicles incorporate various cell-specific components (proteins, lipids and nucleic acids) that can be transferred to target cells. The rigour needed for comparative studies has fueled the search for optimal approaches for their isolation, purification, and characterization. RNA, the newest extracellular vesicle component to be discovered, has received substantial attention as an extracellular vesicle therapeutic, and compelling evidence suggests that ex vivo manipulation of microRNA composition may have uses in the treatment of kidney disorders. The results of these studies are building the case that urinary extracellular vesicles act as mediators of renal pathophysiology. As the field of extracellular vesicle studies is burgeoning, this Review focuses on primary data obtained from studies of human urine rather than on data from studies of laboratory animals or cultured immortalized cells.

尿液是一种有价值的诊断介质，随着尿液中细胞外小泡的发现，尿液被视为一种动态的生物活性液。细胞外囊泡是脂质封闭的结构，可以分为三类：外泌体，微囊泡（或外泌体）和凋亡小体。该分类基于形成膜囊泡的机制：多囊泡体与质膜的融合（外泌体），直接从质膜出芽的囊泡（微囊泡）或从垂死的细胞脱落的囊泡（凋亡小体）。在其形成过程中，尿液细胞外囊泡含有各种可以转移到靶细胞的细胞特异性成分（蛋白质，脂质和核酸）。比较研究所需的严谨性推动了寻找最佳方法来进行隔离的研究，纯化和表征。RNA，是最新发现的细胞外囊泡成分，已作为细胞外囊泡治疗剂受到了广泛关注，令人信服的证据表明，RNAmicroRNA成分的离体操作可能在肾脏疾病的治疗中具有用途。这些研究的结果正在建立尿细胞外囊泡充当肾脏病理生理介质的案例。随着细胞外囊泡研究领域的蓬勃发展，本综述的重点是从人类尿液研究获得的主要数据，而不是实验室动物或培养的永生化细胞研究的数据。