Expression of aquaporin-1 in a long-term peritoneal dialysis patient with impaired transcellular water transport

Aquaporin-1 (AQP1) has been claimed to be the molecular counterpart of the transcellular pathway for free-water movement across the peritoneum during peritoneal dialysis, We report the case of a 67-year-old man, on peritoneal dialysis for 11 years, in whom ultrafiltration failure due to an abolition of the transcellular water transfer (documented by a loss of sodium sievin g) was associated with an apparently normal expression of AQP1, We suggest that an alteration of AQP1 structure, rather than of its expression, accoun ts for this observation. (C) 1999 by the National Kidney Foundation, Inc.