The emerging role of extracellular vesicles as communicators between adipose tissue and pathologic lungs with a special focus on asthma.

Extracellular vesicles (EVs) gain increasing attention due to their (patho-)physiological role in intercellular signaling, specifically in the communication between distant organs. Recent studies highlight a connection between the adipose tissue (AT) and the lung via (immuno-)modulatory EVs in disorders, such as obesity-associated asthma and lung cancer-associated cachexia. While lung cancer-derived EVs induce lipolysis and myotube atrophy in vivo, pathogenic effects were also reported in the opposite direction with involvement of adipose tissue-derived EVs in cancer-promoting responses and potentially in asthma development. In contrast, the majority of studies on adipose tissue-derived EVs demonstrate a protective nature on the asthmatic lung. Beneficial effects, such as induction of anti-inflammatory pathways in vitro and in ovalbumin (OVA)-induced asthma mouse models, were particularly conveyed by EVs enriched from AT-derived mesenchymal stem/stromal cells (AT-MSCs), which therefore pose an interesting subject in possible future therapeutic applications. Likewise, AT-MSC-derived EVs exerted beneficial effects in several other pulmonary abnormalities, such as different types of lung injury or pathological changes related to chronic obstructive pulmonary disease. These contradictory findings highlight the need of extensive research to widen the understanding of EVs in the development of diseases and interconnectivity between organs.