AQP1 and chronic kidney disease: The objective of the present study was to identify a marker of nephropathy in patients with CKD and a marker of rejection in KT recipients by assessing EVs derived from the glomerulus (podocalyxin+), the proximal tubules (aquaporin-1+), the endothelium (CD144+), the immune system (CD19+ B-cells, CD3+ T-cells, CD16+ and CD56+ Natural Killer cells) and the renal progenitors (CD133+).