Exosomes and Other Extracellular Vesicles with High Therapeutic Potential: Their Applications in Oncology, Neurology, and Dermatology

Abstract

Until thirty years ago, it was believed that extracellular vesicles (EVs) were used to remove unnecessary compounds from the cell. Today, we know about their enormous potential in diagnosing and treating various diseases. EVs are essential mediators of intercellular communication, enabling the functional transfer of bioactive molecules from one cell to another. Compared to laboratory-created drug nanocarriers, they are stable in physiological conditions. Furthermore, they are less immunogenic and cytotoxic compared to polymerized vectors. Finally, EVs can transfer cargo to particular cells due to their membrane proteins and lipids, which can implement them to specific receptors in the target cells. Recently, new strategies to produce ad hoc exosomes have been devised. Cells delivering exosomes have been genetically engineered to overexpress particular macromolecules, or transformed to release exosomes with appropriate targeting molecules. In this way, we can say tailor-made therapeutic EVs are created. Nevertheless, there are significant difficulties to solve during the application of EVs as drug-delivery agents in the clinic. This review explores the diversity of EVs and the potential therapeutic options for exosomes as natural drug-delivery vehicles in oncology, neurology, and dermatology. It also reflects future challenges in clinical translation.

Keywords: EVs; drug delivery; exosomes; extracellular vesicles.

Figure 1

Factors that influence the effectiveness of treatment with extracellular vesicles. The origin of EVs affects their features, such as their immunity, toxicity, and therapeutic properties, as they bear the hallmark of the parental cells. Isolation procedures, such as centrifugation techniques, may cause changes in EV membrane structure that lead to the loss and gain of features that may be dangerous for the patient and cannot always be predicted at the design stage. There are differences in experimental conditions for vesicle release between cell culture studies, animal studies, and preclinical studies. The environmental conditions of EV release affect the quality and quantity of EVs; therefore, experimental therapies may have difficulty achieving the target amount of EVs. The injection technique of EV administration affects their pharmacokinetics and bio-distribution. Intravenous injection makes EVs more accessible to the immune system and prone to phagocytosis. The accumulation of EVs in the organs is higher after intravenous injection than after intramuscular or subcutaneous injection, which affects the therapeutic response.