Helsper Shannon, Yuan Xuegang, Jeske Richard, Bhagu Jamini, Esmonde Colin, Duke Leanne, Sun Li, Li Yan, Grant Samuel C
National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL, 32310, United States of America (USA).
Chemical & Biomedical Engineering, FAMU-FSU College of Engineering, Florida State University, Tallahassee, FL, 32310, USA.
ACS Appl Nano Mater. 2024 Oct 25;7(20):24160-24171. doi: 10.1021/acsanm.4c04888. Epub 2024 Oct 9.
Stroke is a leading cause of death and disability worldwide. Extracellular vesicles (EVs) derived from human mesenchymal stem cells (hMSCs) offer a unique and promising alternative to direct cell injection as part of a cell-based therapy for stroke treatment. The development of labeling strategies is essential to identifying the initial biodistribution and clearance of EV-based therapeutics. In this study, hMSC-EVs were labeled with ultrasmall superparamagnetic iron oxide (USPIO) nanoparticles for magnetic resonance imaging (MRI). Two methods of preparation were evaluated after EVs were sonicated in the presence of USPIO nanoparticle. The labeled EVs were purified by (1) ultracentrifugation only or (2) an extension of a harvesting approach that employs polyethylene glycol (PEG) to enrich EVs. Following assessment, labeled EVs were applied to an ischemic stroke model and imaged both immediately and longitudinally using MRI. assessment showed the EV characteristics after USPIO nanoparticle labeling. The PEG method exhibited a 3.6-fold enhancement in contrast using an equivalent USPIO concentration at 0.5 mg/mL and equivalent acquisition parameters (TE = 3.5 ms, TR = 5 s) when the dilution factor is considered. Sufficient USPIO nanoparticle labeling was achieved to visualize initial biodistribution and assess initial therapeutic potential. Taken together, simultaneous USPIO nanoparticle labeling and EV enrichment with PEG enhanced MRI contrast and improved outcomes with respect to delivery and ischemic stroke recovery.
中风是全球范围内导致死亡和残疾的主要原因。源自人间充质干细胞（hMSCs）的细胞外囊泡（EVs）作为基于细胞的中风治疗方法的一部分，为直接细胞注射提供了一种独特且有前景的替代方案。标记策略的发展对于确定基于EV的治疗药物的初始生物分布和清除至关重要。在本研究中，hMSC-EVs用超小超顺磁性氧化铁（USPIO）纳米颗粒进行标记以用于磁共振成像（MRI）。在EVs于USPIO纳米颗粒存在下进行超声处理后，评估了两种制备方法。标记的EVs通过以下方式纯化：（1）仅通过超速离心或（2）扩展一种采用聚乙二醇（PEG）富集EVs的收获方法。评估后，将标记的EVs应用于缺血性中风模型，并立即和纵向使用MRI进行成像。评估显示了USPIO纳米颗粒标记后的EV特性。当考虑稀释因子时，在0.5 mg/mL的等效USPIO浓度和等效采集参数（TE = 3.5 ms，TR = 5 s）下，PEG方法的对比度提高了3.6倍。实现了足够的USPIO纳米颗粒标记以可视化初始生物分布并评估初始治疗潜力。综上所述，同时进行USPIO纳米颗粒标记和用PEG富集EVs增强了MRI对比度，并在递送和缺血性中风恢复方面改善了结果。
