AQP1 and chronic kidney disease: Based on aquaporin 1 expression, we observed that the quantity of proximal tubular cells ranged from 65 ± 2.2% at P3, to 41.2 ± 4.1% at P12 in the NK-derived cells and 62.3 ± 6.2% at P3 to 39.5 ± 3% at P12 in the CKD-derived cells.