Exosomes are extracellular vesicles that are produced by virtually every cell type as a means of intercellular communication. They contain proteins (growth factors), mRNA (blueprint for protein production) and microRNA (on-off switch for specific protein production), all contained within a membrane similar to their parent cells that protects exosomal proteins and RNA from degradation until they are delivered to the target cell. The physiologic effects of the exosomal growth factors can be used to stimulate the healing of acute and chronic wounds, regenerate collagen in aging and damaged skin, and reduce inflammation.
It has been suggested that the mechanism of stem cell-based therapy is related to paracrine secretion of extracellular vesicles (EVs), which are recognized as the main secretion factors of stem cells. EVs, and in particular the subclass exosomes (Exos), are novel therapeutic approaches for treatment of cartilage lesions and OA. The results of recent studies have shown that EVs isolated from mesenchymal stem cells (MSCs) could inhibit OA progression. EVs isolated from various stem cell sources, such as MSCs, may contribute to tissue regeneration of the limbs, skin, heart, and other tissues.