title: Urinary aquaporin-2 excretion before and after transjugular intrahepatic portosystemic shunt insertion for refractory ascites.
abstract: OBJECTIVE
  The role of renal aquaporin-2 (AQP2) water channel turnover in patients with liver cirrhosis, portal hypertension and water retention remains unclear. Transjugular intrahepatic portosystemic shunt (TIPS) insertion reduces portal hypertension, improves water excretion and lowers plasma vasopressin. The aim of this study was to establish whether TIPS insertion decreases urinary AQP2 excretion (uAQP2) in parallel with improved water excretion.
  
  
  METHODS
  Fourteen cirrhosis patients with refractory ascites were studied before TIPS insertion and 4 and 12 weeks after insertion. A 24-h urine collection was followed by an oral water load (20 ml/kg body weight) with a 4-h blood and urine sampling.
  
  
  RESULTS
  TIPS reduced the portal pressure gradient from a median 18(4) (25-75% InterQuartile-range) to 7(2) mmHg, p < 0.05 and the need for diuretics (p < 0.05). TIPS increased plasma sodium from 136(6) mmol/l to 139(4), (p < 0.05) and diuresis from 1650(1043) ml/24 h to 2230(560) (p < 0.05), although the 24-h urinary sodium excretion did not change. There was no change in the baseline uAQP2 before 274(249) ng/(mmol creatinine/24 h) and 12 weeks after TIPS 242(201). There were no systematic changes in uAQP2, plasma vasopressin or other vasoactive substances during the water loads, before or after TIPS.
  
  
  CONCLUSIONS
  The effective amelioration of portal hypertension improved the patient's water excretion and plasma sodium, but there was no change in renal AQP2 trafficking or vasopressin. These findings do not support a primary role for renal AQP2 water channels in portal hypertensive water retention.
authors: Department of Hepatology and Gastroenterology, Aarhus University Hospital , 44 Nørrebrogade, 8000 Aarhus C , Denmark.
authors: Marianne
authors: M
authors: Geilswijk
authors: Karen Louise
authors: KL
authors: Thomsen
authors: Erling Bjerregaard
authors: EB
authors: Pedersen
authors: Hendrik
authors: H
authors: Vilstrup
authors: Henning
authors: H
authors: Grønbæk
mesh_terms: D051399:Aquaporin 2 / Q000652:urine*; D001201:Ascites / Q000209:etiology / Q000601:surgery / Q000652:urine*; D004231:Diuresis; D005260:Female; D006801:Humans; D006975:Hypertension, Portal / Q000209:etiology / Q000503:physiopathology* / Q000601:surgery*; D008103:Liver Cirrhosis / Q000150:complications; D008297:Male; D008875:Middle Aged; D017082:Portal Pressure; D019168:Portasystemic Shunt, Transjugular Intrahepatic; D012964:Sodium / Q000097:blood / Q000652:urine; D014667:Vasopressins / Q000097:blood
chemical_list: D051399:Aquaporin 2; D014667:Vasopressins; D012964:Sodium
keywords: aquaporin2; ascites; liver cirrhosis; portal hypertension; portosystemic shunt; transjugular intrahepatic