Nuclear accidents or acts of terrorism involving radioactive sources might lead to mass casualties irradiation. The hematopoietic system is one of the most critical and radiation-sensitive tissues because the limited life span of blood cells requires the continuous division of hematopoietic stem cells (HSCs) into the bone marrow. The radiation-induced hematopoietic syndrome, RI-HS, is an impairment of the hematopoiesis that will result in pancytopenia of various degrees. In fact, treatment with granulocyte-colony stimulating factor (G-CSF) is considered as a valuable adjunct to treatment controls in some irradiated patients. Nevertheless, these overexposed patients with bone marrow suppression have minimal medullary territories that do not allow complete recovery of hematopoiesis but lead to significant immunoreactivity following allogeneic hematopoietic stem cell transplantation (HSCT). The high morbidity and mortality of these overexposed patients is a reminder of the lack of effective treatment for hematopoietic syndrome. During the last 20 y, a therapeutic approach for mesenchymal stem cells (MSC) has been proposed for the management of accidentally irradiated victims. Many preclinical animal studies have shown that MSC, mainly by their secretory activity, in particular extracellular vesicles (EVs), contribute to the control of inflammation and promote regeneration of tissues by accelerating angiogenesis and re-epithelialization processes. Therefore, we investigated the potential effect of EVs on the reduction of early bone marrow ionization toxicity, early anti-apoptotic therapy, and vascular protection in the RI-HS model. The main purpose is to propose an innovative treatment of non-patient-specific RI-HS emergency treatment in order to limit allogeneic HSC.

中文翻译：

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MSC衍生的细胞外囊泡：新的紧急治疗方法可以限制放射诱发的造血综合症的发展？

涉及放射源的核事故或恐怖主义行为可能导致大量人员伤亡。造血系统是最关键和对放射线敏感的组织之一，因为血细胞的生命周期有限，需要将造血干细胞（HSC）连续分裂成骨髓。辐射诱发的造血综合症RI-HS是造血功能障碍，将导致不同程度的全血细胞减少。实际上，在某些受辐照患者中，粒细胞集落刺激因子（G-CSF）的治疗被认为是治疗控制的有​​价值的辅助手段。不过，这些患有骨髓抑制的过度暴露的患者具有最小的髓质区域，无法完全恢复造血功能，但在同种异体造血干细胞移植（HSCT）后导致明显的免疫反应性。这些过度暴露的患者的高发病率和死亡率提示着缺乏对造血综合症的有效治疗。在过去的20年中，已经提出了一种治疗间充质干细胞（MSC）的方法，用于处理意外照射的受害者。许多临床前动物研究表明，MSC主要通过其分泌活性，特别是细胞外囊泡（EVs），通过加速血管生成和重新上皮形成过程，有助于控制炎症并促进组织再生。因此，我们在RI-HS模型中研究了电动汽车对减少早期骨髓电离毒性，早期抗凋亡治疗以及保护血管的潜在作用。主要目的是提出一种针对非患者的RI-HS紧急治疗的创新治疗方法，以限制同种HSC。