Nowadays, a large population around the world, especially the elderly, suffers from neurological inflammatory and degenerative disorders/diseases. Current drug delivery strategies are facing different challenges because of the presence of the BBB, which limits the transport of various substances and cells to brain parenchyma. Additionally, the low rate of successful cell transplantation to the brain injury sites leads to efforts to find alternative therapies. Stem cell byproducts such as exosomes are touted as natural nano-drug carriers with 50–100 nm in diameter. These nano-sized particles could harbor and transfer a plethora of therapeutic agents and biological cargos to the brain. These nanoparticles would offer a solution to maintain paracrine cell-to-cell communications under healthy and inflammatory conditions. The main question is that the existence of the intact BBB could limit exosomal trafficking. Does BBB possess some molecular mechanisms that facilitate the exosomal delivery compared to the circulating cell? Although preliminary studies have shown that exosomes could cross the BBB, the exact molecular mechanism(s) beyond this phenomenon remains unclear. In this review, we tried to compile some facts about exosome delivery through the BBB and propose some mechanisms that regulate exosomal cross in pathological and physiological conditions.

中文翻译：

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外泌体通过血脑屏障传递治疗调节剂；承诺和陷阱

如今，世界上有大量人口，尤其是老年人，患有神经炎症和退行性疾病/疾病。由于血脑屏障的存在，当前的药物递送策略面临着不同的挑战，血脑屏障限制了各种物质和细胞向脑实质的转运。此外，脑损伤部位的细胞移植成功率低，导致人们努力寻找替代疗法。外泌体等干细胞副产品被吹捧为直径为 50-100 nm 的天然纳米药物载体。这些纳米尺寸的颗粒可以携带大量的治疗剂和生物物质并将其转移到大脑中。这些纳米颗粒将提供一种在健康和炎症条件下维持旁分泌细胞间通讯的解决方案。主要问题是完整 BBB 的存在可以限制外泌体的贩运。与循环细胞相比，BBB 是否具有一些促进外泌体递送的分子机制？尽管初步研究表明外泌体可以穿过 BBB，但超越这种现象的确切分子机制仍不清楚。在这篇综述中，我们试图汇编关于通过 BBB 传递外泌体的一些事实，并提出一些在病理和生理条件下调节外泌体交叉的机制。除了这种现象之外，确切的分子机制仍不清楚。在这篇综述中，我们试图汇编关于通过 BBB 传递外泌体的一些事实，并提出一些在病理和生理条件下调节外泌体交叉的机制。除了这种现象之外，确切的分子机制仍不清楚。在这篇综述中，我们试图汇编关于通过 BBB 传递外泌体的一些事实，并提出一些在病理和生理条件下调节外泌体交叉的机制。