The exosome as a transporter of diseases and treatments

This infographic, found on The Scientist website, shows a basic understanding of exosomes, which carry proteins outside of the cell. Click the link to see it larger.

General

Exosomes were once thought to discard waste outside the cell. 7th Space Interactive, however, just published an article saying that according to some studies in the Journal of Neuroinflammation, exosomes also transfer proteins between cells.

This concept is not entirely new, as a 2011 article published on The Scientist called "Exosome Explosion" looks at the exosome as a cell signal transmitter that carries not just proteins, but protein precursors (like mRNA).

Disease Carriers

Exosomes have been found to carry infected material between cells, contributing to the growth of cancer, as explained in this article from PubMed. Additionally, exosomes may export therapeutic drugs, inhibiting their effectiveness.

The article from 7th Space Interactive also says that, in neurological pathways, the build up of neurotoxins may cause cellular damage and may contribute to Alzheimer's, Parkinson's and other neurological diseases. 

Treatments

A study done by the Department of Physiology, Anatomy, and Genetics at the University of Oxford looked at synthetic exosome delivery of drugs as a possible route for treatment of neurodiseases, according to Molecular Therapy.  The exosomes could possibly carry tumor inhibitors, as stated in the article:

Zhuang et al.1 build on previous findings by the same researchers that T-cell-derived exosomes are preferentially taken up by immature myeloid cells such as macrophages and microglial cells.10 Given the selective uptake of exosomes by macrophages, already demonstrated by these authors, and the newly established properties of exosomes as drug delivery vehicles,8 Zhuang and colleagues investigated whether T-cell-derived exosomes could be used to deliver anti-inflammatory agents specifically to microglial cells in the brain. They used a noninvasive intranasal route to bypass the BBB. Unloaded exosomes derived from a variety of mouse cell lines and labeled with a biological dye were first administered intranasally 2 µg at a time over a 10-minute period. Labeled exosomes were detected in the olfactory bulb within 30 minutes and up to 24 hours after administration. Multiorgan imaging demonstrated their selective homing to the brain and, to a lesser extent, the intestine. These initial experiments with unloaded exosomes demonstrated their fast and selective homing to the brain after intranasal administration.