Exosomes and the kidney: Blaming the messenger

Exosomes are membrane-bound vesicles of endosomal origin, present in awide range of biological fluids, including blood and urine. They rangebetween 30 and 100 nm in diameter, and consist of a limiting lipid bilayer,transmembrane proteins and a hydrophilic core containing proteins,mRNAs and microRNAs (miRNA). Exosomes can act as extracellular vehi-cles by which cells communicate, through the delivery of their functionalcargo to recipient cells, with many important biological, physiologicaland pathological implications. The exosome release pathway contributestowards protein secretion, antigen presentation, pathogen transfer andcancer progression. Exosomes and exosome-mediated signalling have beenimplicated in disease processes such as atherosclerosis, calcification andkidney diseases. Circulating levels of exosomes and extracellular vesicles canbe influenced by the progression of renal disease. Advances in methods forpurification and analysis of exosomes are leading to potential diagnostic andtherapeutic avenues for kidney diseases. This review will focus on biophysi-cal properties and biogenesis of exosomes, their pathophysiological rolesand their potential as biomarkers and therapeutics in kidney diseases