Exosomes – small membrane-bound vesicles typically below 100 nm in diameter- are secreted by cells under normal and pathological conditions, and they serve a number of functions depending on the type of cell they originate from. This relationship has been exploited to advance exosomes as therapeutic agents. They contain both protein and RNA, the nature of which is being collected in a public compendium called ExoCarta.
In stem cell therapy – particularly MSC-related – exosomes have become attractive as they are thought to be able to confer the therapeutic efficiency of their originating stem cell without any of the more severe drawbacks relating to the safety of stem cell transplantation.
A large number of papers have appeared investigating this effect, and the application of exosomes as cell therapy agents.
A new study by the lab of Dr. Stanislav Tomarev at the National Eye Institute at the National Institutes of Health described the use of MSC-derived exosomes for the improvement of loss of vision through the loss of loss of retinal ganglion cells and their axons.
Titled Bone Marrow-Derived Mesenchymal Stem Cells-Derived Exosomes Promote Survival of Retinal Ganglion Cells Through miRNA-Dependent Mechanisms, the manuscript was published in Stem Cells Translational Medicine.
The authors described the isolation of exosomes from bone marrow-derived stem cells by ultracentrifugation. These exosomes, which the authors showed to be secreted in similar quantities as fibroblast control cells, were successfully delivered to growing injured retinal ganglion cells, a type of CNS neuron, and were shown to support MSC-like neutirogenic activity.
When delivered to the eye in a rat optic nerve crush (ONC) model, exosomes provided a significant neuroprotective effect and preserved retinal ganglion cell function.
As a first study to demonstrate successful therapeutic delivery of exosomes to the eye, the manuscript also investigates the effect of exosome-carried protein and miRNA, in order to attempt to decouple their individual roles.