Gut-derived endotoxin stimulates factor VIII secretion from endothelial cells. Implications for hypercoagulability in cirrhosis

J Hepatol. 2017 Nov;67(5):950-956. doi: 10.1016/j.jhep.2017.07.002. Epub 2017 Jul 14.

Abstract

Background & aims: Patients with cirrhosis display enhanced blood levels of factor VIII, which may result in harmful activation of the clotting system; however, the underlying mechanism is unknown.

Methods: We performed a cross-sectional study in patients with cirrhosis (n=61) and matched controls (n=61) comparing blood levels of factor VIII, von Willebrand factor (vWf), lipopolysaccharide (LPS) and positivity for Escherichia coli DNA. Furthermore, we performed an in vitro study to investigate if LPS, in a concentration range similar to that found in the peripheral circulation of cirrhotic patients, was able to elicit factor VIII secretion from human umbilical vein endothelial cells (HUVEC).

Results: Patients with cirrhosis displayed higher serum levels of LPS (55.8 [42.2-79.9] vs. 23.0 [7.0-34.0]pg/ml, p<0.001), factor VIII (172.0 [130.0-278.0] vs. 39.0 [26.0-47.0]U/dl, p<0.0001), vWf (265.0 [185.0-366.0] vs. 57.0 [48.0-65.0]U/dl, p<0.001) and positivity for Escherichia coli DNA (88% vs. 3%, p<0.001, n=34) compared to controls. Serum LPS correlated significantly with factor VIII (r=0.80, p<0.001) and vWf (r=0.63, p<0.001). Only LPS (beta-coefficient=0.70, p<0.0001) independently predicted factor VIII levels. The in vitro study showed that LPS provoked factor VIII and vWf release from HUVEC via formation and secretion of Weibel-Palade bodies, a phenomenon blunted by pre-treating HUVEC with an inhibitor of Toll-like receptor 4.

Conclusions: The study provides the first evidence that LPS derived from gut microbiota increases the systemic levels of factor VIII via stimulating its release by endothelial cells. Lay summary: Cirrhosis is associated with thrombosis in portal and systemic circulation. Enhanced levels of factor VIII have been suggested to play a role but the underlying mechanism is still unclear. Here we show that patients with cirrhosis display a concomitant increase of factor VIII and lipopolysaccharide (LPS) from Escherichia coli and suggest that LPS contributes to the release of factor VIII from endothelial cells.

Keywords: Cirrhosis; Endotoxin; Factor VIII; Hypercoagulability; LPS; von Willebrand factor.

MeSH terms

  • Cross-Sectional Studies
  • DNA, Bacterial / analysis
  • Endotoxins / metabolism*
  • Escherichia coli / genetics
  • Factor VIII / analysis
  • Factor VIII / metabolism*
  • Female
  • Gastrointestinal Microbiome / physiology
  • Human Umbilical Vein Endothelial Cells / metabolism
  • Humans
  • Italy
  • Lipopolysaccharides / analysis
  • Liver Cirrhosis* / blood
  • Liver Cirrhosis* / complications
  • Male
  • Middle Aged
  • Thrombophilia* / diagnosis
  • Thrombophilia* / etiology
  • Thrombophilia* / metabolism
  • Weibel-Palade Bodies / metabolism
  • von Willebrand Factor / analysis
  • von Willebrand Factor / metabolism*

Substances

  • DNA, Bacterial
  • Endotoxins
  • Lipopolysaccharides
  • von Willebrand Factor
  • endotoxin, Escherichia coli
  • Factor VIII