Characteristics of extracellular vesicles and their potential role in organ-cross talk after multiple trauma

不同的身体隔室之间的沟通，组织也可以影响远端组织，已经获得了越来越多的兴趣。根据几项观察，这一过程被称为“器官串扰”，似乎也与多发创伤（MT）有关。首先，对身体不同部位的损伤所造成的全身影响已被证明远远大于孤立的创伤性损伤的总和。其次，主要未受影响的器官的各种创伤后功能障碍已被描述。这些观察结果可能导致多器官功能障碍综合征（MODS）的发展，这仍然是MT患者最常见的并发症之一。众所周知，创伤后免疫反应在MT后不同身体区室的相互作用和器官功能障碍的发展中都起着关键作用。由于不同身体区域的损伤与不同的局部炎症反应有关，这些炎症反应可能积聚成潜在有害的全身炎症反应，因此首次有证据表明，多种细胞(如器官特异性巨噬细胞、内皮细胞和成骨细胞)可能参与上述过程。基于ev的串扰代表了一种重要的细胞-细胞通信模式，它通过分子表面或分子（如蛋白质、线粒体DNA、mRNA）转移到其他细胞中发挥作用。这些相互作用可以导致相似细胞之间的功能同步或不同细胞类型的协调。尽管EV与创伤后器官串扰有潜在的相关性，但尚不清楚它们的起源和释放模式是否取决于持续损伤的严重程度和分布。在这种情况下，器官特异性EV可能仅在器官本身直接损伤的情况下释放，也可能由于“间接”创伤性影响，如全身损伤（创伤出血（TH））或其他身体隔室损伤。此外，还没有对EV的子集组成、内容和功能进行详细的表征。因此，在这个项目中，我们计划：a)在一个完善的猪MT模型中研究与损伤模式相关的EV局部和全身释放。在分离这些局部和全身EV后，还将对其来源和含量进行表征，b)用从猪MT模型中分离的EV在体外刺激器官特异性细胞系，以阐明EV对细胞功能的作用，c)翻译比较大型动物模型和人类情况下EV的全身释放模式（NTF Biobank），并将这些发现与临床并发症的发展和患者的结果联系起来。

The communication of different body compartments through which tissue can affect also distant tissues has gained increasing interest. Due to several observations, this process termed “organ cross-talk” also seems to be of major relevance after multiple trauma (MT). First, the systemic effects of injuries to different body compartments have been shown to be far greater than the sum of the isolated traumatic insults. Second, various posttraumatic dysfunctions of primarily unaffected organs have been described. These observations can contribute to the development of multiple organ dysfunction syndrome (MODS), which is still one of the most common complications in MT patients who survive the initial insult. The posttraumatic immune response is well known to play a key role in both, the interaction of diverse body compartments and the development of organ dysfunction after MT. As injuries of different body regions are associated with distinct local inflammatory responses, which can accumulate in a potentially harmful systemic inflammatory reaction, there is first evidence that also extracellular vesicles (EV), generated from a variety of cells (e.g. organ specific macrophages, endothelial cells and osteoblasts), might be involved in the aforementioned processes. EV-based crosstalk represents a substantial cell-cell communication pattern that exerts its effects either via molecular surfaces or by the transfer of molecules (e.g. proteins, mitochondrial DNA, mRNA) into other cells. These interactions can result in a synchronization of functions among similar cells or a coordination of different cell types. Despite the potential relevance of EV for posttraumatic organ cross-talk, it is unknown if their origin and release pattern is dependent on both, the severity and distribution of the sustained injury. In this context, organ-specific EV might be released either only in case of a direct injury to the organ itself or also due to “indirect” traumatic impacts, such as systemic insults (trauma hemorrhage (TH)) or injuries to other body compartments. Furthermore, detailed characterization of EV in regard to subset composition, their content and function has not been performed. With this project we therefore plan to: a) investigate the injury pattern-dependent local and systemic release of EV in a well-established MT model in pigs. After isolating these local and systemic EV, also characterization of their origin and content will be performed, b) stimulate organ-specific cell lines in vitro with isolated EV from the porcine MT model to illuminate EV-function on cell function and c) translationally compare the systemic release pattern of EV from the large animal model to the human situation (NTF Biobank) and correlate these findings to the development of clinical complications and patients’ outcome.