Circulating soluble vascular adhesion protein 1 accounts for the increased serum monoamine oxidase activity in chronic liver disease

Gastroenterology. 2000 Oct;119(4):1096-103. doi: 10.1053/gast.2000.18163.


Background & aims: Vascular adhesion protein 1 (VAP-1) is an endothelial glycoprotein that supports adhesion of lymphocytes to hepatic endothelium and has sequence homology with semicarbazide-sensitive amine oxidases (SSAOs). We investigated whether soluble VAP-1 (sVAP-1) displays SSAO activity and thereby accounts for increased monoamine oxidase activity in the serum of patients with liver diseases.

Methods: sVAP-1 concentration and SSAO activity were measured in peripheral, hepatic, and portal blood and in bile from patients with liver disease and in peripheral blood of control subjects, using enzyme-linked immunosorbent assay and enzymatic assays.

Results: sVAP-1 concentration (mean [+/-SE], 143. 67 [34.97-92.67] ng/mL) and SSAO activity (18.8 [12.0-24.6] nmol. mL(-1). h(-1)) were significantly increased in chronic liver diseases compared with healthy controls (87.1 [53.5-127] ng/mL [P<0.001] and 10.7 [6.5-12.7] nmol. mL(-1) x h(-1) [P<0.05]) but not in massive necrosis caused by paracetamol poisoning (109 [80.3-140] ng/mL and 8.9 [5.7-12.3] nmol. mL(-1) x h(-1)). sVAP-1 correlated with serum transaminase and bilirubin but not with creatinine. In 5 paired samples, sVAP-1 concentration was higher in hepatic (median, 113 [range, 53-122]) than in portal vein (102 [42-109]; 2P<0.05), and was not detected in bile. There was a highly significant correlation between serum sVAP-1 and SSAO activity in normal subjects, patients with acute liver failure, and those with chronic liver disease (r = 0.895; P<0.001). When serum was depleted of sVAP-1 by immunoaffinity chromatography, SSAO activity was eliminated.

Conclusions: sVAP-1 levels are increased in chronic liver disease, and sVAP-1 is likely derived from the liver. Serum sVAP-1 displays SSAO activity and accounts for most of the monoamine oxidase activity in human serum.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amine Oxidase (Copper-Containing) / blood*
  • Aspartate Aminotransferases / blood
  • Bile / enzymology
  • Bilirubin / blood
  • Biomarkers / blood
  • Carcinoma, Hepatocellular / blood
  • Cell Adhesion Molecules / blood*
  • Chronic Disease
  • Colorectal Neoplasms / blood
  • Creatinine / blood
  • Enzyme-Linked Immunosorbent Assay
  • Hepatitis / blood*
  • Hepatitis / classification
  • Hepatitis, Alcoholic / blood
  • Humans
  • Liver Circulation
  • Liver Cirrhosis, Alcoholic / blood
  • Liver Diseases / blood*
  • Liver Diseases / pathology
  • Liver Failure, Acute / blood
  • Liver Neoplasms / blood
  • Liver Transplantation
  • Monoamine Oxidase / blood*
  • Portal System
  • Reference Values
  • Sialoglycoproteins / blood


  • Biomarkers
  • Cell Adhesion Molecules
  • Sialoglycoproteins
  • Creatinine
  • AOC3 protein, human
  • Amine Oxidase (Copper-Containing)
  • Monoamine Oxidase
  • Aspartate Aminotransferases
  • Bilirubin