Preparing Biotherapeutic Extracellular Vesicles: Ultrafilters, Mesenchymal Stem Cells, and the Regulatory Horizon

by Chandreyee Das, PhD
Volume 14, Issue 2 (Summer 2015)

Extracellular vesicles (EVs) are particles of varying size, structure, and composition, which are secreted from cells and frequently mediate intercellular communication. Because they have been shown to travel through the circulatory system and also through biological barriers to deliver their molecular contents to distant target cells, there has been growing interest in using EVs, such as exosomes, as drug delivery vehicles. In the past ten years, the number of published articles linking EVs to drug delivery has increased 20-fold. EVs are being engineered to deliver protein, RNA, and small molecule cargo to target cells, tissues, and entire systems. Also, EVs derived from certain cells show inherent, therapeutically beneficial activity. For example, EVs prepared from antigen-presenting cells can be used like vaccines to elicit a desired immune response from a host. The idea of using lipid-based carriers to deliver drugs is, of course, not new. Liposomes were first introduced as delivery vehicles in the 1960s, and some liposome-formulated drugs have made it to market. However, developers of liposome-based therapies are still trying to overcome the challenges of particle clearance by the immune system, immunogenicity, and the lack of specificity in targeting these particles to particular cell types. From this perspective, EVs are an attractive alternative to synthetic liposomes. They have already demonstrated stability in the circulatory system, and because of the proteins embedded in EV membranes, they reach target cells and are taken up more efficiently...

Das C. Preparing biotherapeutic extracellular vesicles: ultrafilters, mesenchymal stem cells, and the regulatory horizon. BioProcess J, 2015; 14(2): 50–3.

Posted online July 10, 2015.