The cardiovascular and haematopoietic systems have fundamental inter-relationships during development, as well as in health and disease of the adult organism. Although haematopoietic stem cells (HSCs) emerge from a specialized haemogenic endothelium in the embryo, persistence of haemangioblasts in adulthood is debated. Rather, the vast majority of circulating stem cells (CSCs) is composed of bone marrow-derived HSCs and the downstream haematopoietic stem/progenitors (HSPCs). A fraction of these cells, known as endothelial progenitor cells (EPCs), has endothelial specification and vascular tropism. In general, the levels of HSCs, HSPCs, and EPCs are considered indicative of the endogenous regenerative capacity of the organism as a whole and, particularly, of the cardiovascular system. In the last two decades, the research on CSCs has focused on their physiologic role in tissue/organ homoeostasis, their potential application in cell therapies, and their use as clinical biomarkers. In this review, we provide background information on the biology of CSCs and discuss in detail the clinical implications of changing CSC levels in patients with cardiovascular risk factors or established cardiovascular disease. Of particular interest is the mounting evidence available in the literature on the close relationships between reduced levels of CSCs and adverse cardiovascular outcomes in different cohorts of patients. We also discuss potential mechanisms that explain this association. Beyond CSCs' ability to participate in cardiovascular repair, levels of CSCs need to be interpreted in the context of the broader connections between haematopoiesis and cardiovascular function, including the role of clonal haematopoiesis and inflammatory myelopoiesis.

中文翻译：

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循环干细胞和心血管结果：从基础科学到临床


心血管和造血系统在发育过程中以及在成人机体的健康和疾病中具有基本的相互关系。尽管造血干细胞 (HSC) 是从胚胎中专门的造血内皮细胞产生的，但成血成血管细胞在成年期的持续存在仍存在争议。相反，绝大多数循环干细胞 (CSC) 由骨髓来源的 HSC 和下游造血干细胞/祖细胞 (HSPC) 组成。这些细胞的一部分，称为内皮祖细胞（EPC），具有内皮特异性和血管向性。一般来说，HSC、HSPC 和 EPC 的水平被认为代表了整个生物体，特别是心血管系统的内源再生能力。在过去的二十年中，CSC 的研究重点是它们在组织/器官稳态中的生理作用、它们在细胞治疗中的潜在应用以及它们作为临床生物标志物的用途。在这篇综述中，我们提供了 CSC 生物学的背景信息，并详细讨论了患有心血管危险因素或已确诊心血管疾病的患者 CSC 水平变化的临床意义。特别令人感兴趣的是文献中越来越多的证据表明，不同患者群体中 CSC 水平降低与不良心血管结局之间存在密切关系。我们还讨论了解释这种关联的潜在机制。除了 CSC 参与心血管修复的能力之外，CSC 的水平还需要在造血和心血管功能之间更广泛的联系（包括克隆造血和炎症性骨髓生成的作用）的背景下进行解释。