AQP1 and chronic kidney disease: Comparison of different stages of CKD have shown that AQP1 and AQP2 are significantly reduced in stages 4 and 5 of CKD at a high level of diagnostic accuracy (Oshikawa-Hori et al., 2021), which increases when uEVs AQP and AQP2 are considered in combination as markers of advanced CKD.