Editorial Comment Urinary exosomes: is there a future?

disease; protein mass spectrometry; urine; vasopressin Tiny vesicles called ‘exosomes’, recently discovered in nor-mal urine [1], provide a non-invasive means of acquiring unique information about the physiological or pathophys-iological state of their renal cells of origin. Exosomes are delivered to the urine from all renal epithelial cell types. Consequently, analysis of urinary exosomesmay pro-vide a source of protein biomarkers for diseases involving glomerular podocytes, the various renal tubule segments or the transitional epithelium lining the urinary drainage tract [1]. Here, we discuss possible applications of urinary ex-osome analysis, as well as barriers to the development of practical clinical tools for exosome analysis. Exosomes originate as the internal vesicles of multi-vesicular bodies (MVBs) in cells (Figure 1). They wer