Magnetic resonance imaging of ultrasmall superparamagnetic iron oxide-labeled exosomes from stem cells: a new method to obtain labeled exosomes.
Magnetic resonance imaging of ultrasmall superparamagnetic iron oxide-labeled exosomes from stem cells: a new method to obtain labeled exosomes.
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DOI：
10.2147/ijn.s104152
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发表时间：
2016
影响因子：
8
通讯作者：
Mariotti R
中科院分区：
文献类型：
--
作者：
Busato A;Bonafede R;Bontempi P;Scambi I;Schiaffino L;Benati D;Malatesta M;Sbarbati A;Marzola P;Mariotti R
最近的研究结果表明，在几种神经退行性实验模型中报道的脂肪干细胞（ASC）的有益作用可能是由于它们由外泌体释放介导的旁分泌活性。本研究的目的是开发和验证一种创新的外泌体标记方案，该方案允许使用磁共振成像（MRI）对其进行可视化。首先，使用超小超顺磁性氧化铁纳米颗粒（USPIO，4-6 nm）标记ASCs，并研究了标记ASCs的细胞活力、标记效率、铁含量和磁共振（MR）图像对比度方面的最佳参数。然后使用标准分离方案从标记的ASC中分离外来体。外泌体标记的效率通过在体外和体内获取MR图像以及通过测定它们的铁含量来评估。进行透射电子显微镜图像和组织学分析以验证所获得的结果。通过使用ASC标记的优化实验参数（200 µg Fe/mL USPIO和72小时孵育），可以标记100%的细胞，而它们的活力仍然与未标记的细胞相当;体外和体内MR图像的检测限分别为102和2.5×103个ASC。从先前标记的ASC中分离的外泌体保留纳米颗粒，如透射电子显微镜图像所示。MRI的体外和体内检测限分别为3 µg和5 µg外泌体。我们报告了一种通过USPIO标记外泌体的新方法，该方法允许通过MRI检测，同时保留其形态学和生理学特征。
Recent findings indicate that the beneficial effects of adipose stem cells (ASCs), reported in several neurodegenerative experimental models, could be due to their paracrine activity mediated by the release of exosomes. The aim of this study was the development and validation of an innovative exosome-labeling protocol that allows to visualize them with magnetic resonance imaging (MRI). At first, ASCs were labeled using ultrasmall superparamagnetic iron oxide nanoparticles (USPIO, 4–6 nm), and optimal parameters to label ASCs in terms of cell viability, labeling efficiency, iron content, and magnetic resonance (MR) image contrast were investigated. Exosomes were then isolated from labeled ASCs using a standard isolation protocol. The efficiency of exosome labeling was assessed by acquiring MR images in vitro and in vivo as well as by determining their iron content. Transmission electron microscopy images and histological analysis were performed to validate the results obtained. By using optimized experimental parameters for ASC labeling (200 µg Fe/mL of USPIO and 72 hours of incubation), it was possible to label 100% of the cells, while their viability remained comparable to unlabeled cells; the detection limit of MR images was of 102 and 2.5×103 ASCs in vitro and in vivo, respectively. Exosomes isolated from previously labeled ASCs retain nanoparticles, as demonstrated by transmission electron microscopy images. The detection limit by MRI was 3 µg and 5 µg of exosomes in vitro and in vivo, respectively. We report a new approach for labeling of exosomes by USPIO that allows detection by MRI while preserving their morphology and physiological characteristics.