Summary
Liver disease is associated with markedly elevated plasma factor VIII (FVIII) levels,
whereas the synthesis of many other coagulation factors and proteins is reduced. In
order to define the mechanism of FVIII increase, we have determined the expression
levels of FVIII, both at mRNA and protein level, in patients with liver disease who
underwent partial liver resection. In addition, the expression of von Willebrand factor
(VWF) and low density lipoprotein receptor-related protein (LRP), proteins known for
their ability to modulate FVIII plasma levels, were examined. Tissue samples for RNA
extraction were obtained from 4 patients with cirrhosis, 9 patients with liver failure
without cirrhosis and 6 patients with liver metastasis of a colon or rectum carcinoma
(control group). In patients with liver cirrhosis hepatic FVIII and LRP mRNA levels
were significantly lower than controls (p ≤ 0.010), while VWF mRNA was significantly
higher (p ≤ 0.050). Immunohistochemical analysis revealed that cellular VWF protein
distribution was also increased in cirrhotic livers compared to liver tissue from
patients with non-cirrhotic liver disease. In cirrhotic tissue enlarged portal veins
appeared to overgrow FVIII producing sinusoidal endothelial cells. Similarly, the
number of LRP-producing cells appeared to be lower in cirrhotic tissue than in controls.
The plasma concentration of both FVIII and VWF was significantly higher in patients
with cirrhosis than control subjects (p = 0.038 and 0.010 respectively). These results
demonstrate that elevated plasma FVIII levels in liver cirrhosis are associated with
increased hepatic biosynthesis of VWF and decreased expression of LRP, rather than
increased FVIII synthesis.
Keywords
Factor VIII - liver cirrhosis - low density lipoprotein receptor-related protein -
von Willebrand factor