Mesenchymal stem cells (MSCs) are the most frequently used stem cells in clinical trials due to their easy isolation from various adult tissues, their ability of homing to injury sites and their potential to differentiate into multiple cell types. However, the realization that the beneficial effect of MSCs relies mainly on their paracrine action, rather than on their engraftment in the recipient tissue and subsequent differentiation, has opened the way to cell-free therapeutic strategies in regenerative medicine. All the soluble factors and vesicles secreted by MSCs are commonly known as secretome. MSCs secretome has a key role in cell-to-cell communication and has been proven to be an active mediator of immune-modulation and regeneration both in vitro and in vivo. Moreover, the use of secretome has key advantages over cell-based therapies, such as a lower immunogenicity and easy production, handling and storage. Importantly, MSCs can be modulated to alter their secretome composition to better suit specific therapeutic goals, thus, opening a large number of possibilities. Altogether these advantages now place MSCs secretome at the center of an important number of investigations in different clinical contexts, enabling rapid scientific progress in this field.

中文翻译：

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间充质干细胞分泌组：无细胞再生医学的基石。

间充质干细胞（MSC）是临床试验中最常用的干细胞，因为它们易于与各种成年组织隔离，具有归巢到损伤部位的能力以及分化成多种细胞类型的潜力。然而，认识到MSC的有益作用主要取决于它们的旁分泌作用，而不是取决于它们在受体组织中的植入和随后的分化，这为再生医学中的无细胞治疗策略开辟了道路。MSC分泌的所有可溶性因子和囊泡通常被称为分泌组。的MSC分泌蛋白质在细胞-细胞通信的关键作用，并已被证明是免疫调制和再生两者的活性介体在体外和体内。此外，与基于细胞的疗法相比，分泌蛋白组的使用具有关键优势，例如免疫原性较低，易于生产，处理和储存。重要的是，可以对MSC进行调节以改变其分泌组组成，以更好地适应特定的治疗目标，从而开辟了许多可能性。现在，这些优势合起来使MSCs分泌蛋白组成为不同临床背景下许多重要研究的中心，从而使该领域的科学进展迅速。