Exosomes in chronic respiratory diseases.

Exosomes are nano-sized vesicles released by almost all cell types, with a central role as mediators of intercellular communication. In addition to physiological conditions, these extracellular vesicles seem to play a pivotal role in inflammatory processes. This assumption offers the opportunity to study exosomes as promising biomarkers and therapeutic tools for chronic respiratory disorders. Indeed, although it is well-known that at the basis of conditions like asthma, chronic obstructive pulmonary disease, alpha-1 antitrypsin deficiency and idiopathic pulmonary fibrosis there is a dysregulated inflammatory process, an unequivocal correlation between different phenotypes and their pathophysiological mechanisms has not been established yet. In this review, we report and discuss some of the most significant studies on exosomes from body fluids of subjects affected by airway diseases. Furthermore, the most widespread techniques for exosome isolation and characterization are described. Further studies are needed to answer the unresolved questions about the functional link between exosomes and chronic respiratory diseases.