Mesenchymal stem cells (MSC) secrete extracellular vesicles (EVs) in order to have effect and communicate through a paracrine effect with the surrounding cells and tissues. Exosomes are a type of EV that is secreted from many cells throughout the body, but the exosomes secreted from stem cells is what has been of interest in medical research. The messenger RNA, micro-RNA, and proteins found in exosomes have been shown to stimulate numerous pathways upon uptake.
Instead of utilizing stem cells which are more fragile and require delicate protocols for preservation and are also difficult to obtain in large quantities, the secretory products of stem cells (exosomes) have been investigated to evaluate whether these vesicles obtained in an exogenous environment can be just as clinically effective or better than stem cells themselves. The EV cargo within exosomes differs based on the stem cells surrounding microenvironment when the exosomes are secreted. Utilizing exosomes that contain cargo similar to an exosome secreted from a stem cell in a similar microenvironment is essential to obtaining comparable effects as MSC treatments seen in clinical trials.
Utilizing billions of exosomes that have potential secretory effects similar to stem cells but without having to deal with the intricacies of the cells themselves is why there is much interest within exosome clinical research. Genetic engineering of the RNA material and incorporating small molecule therapies into exosomes as delivery vehicles to the body is current topic in clinical research.