Labeling and Magnetic Resonance Imaging of Exosomes Isolated from Adipose Stem Cells

Abstract

Adipose stem cells (ASC) represent a promising therapeutic approach for neurodegenerative diseases. Most biological effects of ASC are probably mediated by extracellular vesicles, such as exosomes, which influence the surrounding cells. Current development of exosome therapies requires efficient and noninvasive methods to localize, monitor, and track the exosomes. Among imaging methods used for this purpose, magnetic resonance imaging (MRI) has advantages: high spatial resolution, rapid in vivo acquisition, and radiation-free operation. To be detectable with MRI, exosomes must be labeled with MR contrast agents, such as ultra-small superparamagnetic iron oxide nanoparticles (USPIO). Here, we set up an innovative approach for exosome labeling that preserves their morphology and physiological characteristics. We show that by labeling ASC with USPIO before extraction of nanovesicles, the isolated exosomes retain nanoparticles and can be visualized by MRI. The current work aims at validating this novel USPIO-based exosome labeling method by monitoring the efficiency of the labeling with MRI both in ASC and in exosomes. © 2017 by John Wiley & Sons, Inc.

Exosomes from mesenchymal stem/stromal cells: a new therapeutic paradigm

“…Near-infrared (NIR) dyes are ideal for in vivo applications due to their high signal/noise ratio [24]. EVs with superparamagnetic iron oxide nanoparticles for high resolution and sensitive magnetic resonance analysis provide for accurate detection also in deep organs [25]. In an intracerebral hemorrhage rat model, DiI-labeled MSC-derived exosomes reached brain, liver, lung, and spleen after intravenous injection [26].…”

Exploiting the Natural Properties of Extracellular Vesicles in Targeted Delivery towards Specific Cells and Tissues

“…They have the additional advantage that they can be used to facilitate EV isolation using magnets [40,136] and for simultaneous therapy using a magnetic field [40]. These NPs have also been effectively incorporated into EVs and used for in vivo imaging by magnetic particle imaging [79] and MRI [2,43,137]. Other authors have encapsulated quantum dots (QDs) into EVs.…”

Use of exosomes as vectors to carry advanced therapies

“…95 Adipose stem cell, primary neuronal cells or macrophages have been also incubated with iron nanoparticles (USPIOs or SPIONS) and then EVs loaded within them were puried in order to generate microvesicles for MRI imaging and photodynamic therapy in vivo. [96][97][98] Although some authors suggest that the indirect labeling of source cells is not recommended for exosome loading, [99][100][101] it is one of the most widely employed techniques to achieve the encapsulation of NPs within exosomes (together with electroporation strategies).…”