Relationship between thrombopoietin serum levels and liver function in patients with chronic liver disease related to hepatitis C virus infection.

Objectives: Thrombopoietin (Tpo) is an important regulator of megakaryocyte maturation and platelet production, and is mainly produced by the liver. A decrease in Tpo production is partly responsible for the thrombocytopenia observed in patients with chronic liver disease (CLD). The aim of this study was to evaluate the relationship between Tpo serum levels and liver function in patients with CLD related to hepatitis C virus (HCV) infection.

Methods: We studied 37 patients with various degrees of HCV-related CLD. Of the patients, 17 had chronic hepatitis and 20 liver cirrhosis. Liver function was evaluated in all patients by the following hepatic blood flow dependent and independent tests that explore various hepatic metabolic functions: carbon-13 (13C)-aminopyrine breath test (13C-ABT), 13C-galactose breath test (13C-GBT), and monoethylglycinexylidide (MEGX) test. Liver function tests results were correlated with Tpo serum levels.

Results: Tpo serum levels were significantly lower in patients with liver cirrhosis (88 +/- 23 pg/ml) as compared to those in patients with chronic hepatitis (128 +/- 55 pg/ml, p=0.0031). However, they did not correlate with serum albumin, bilirubin, or prothrombin activity. Tpo serum levels showed a significant positive correlation with 13C-ABT results (hourly dose at 30 min, rs=0.489, p=0.002; cumulative dose at 120 min, rs=0.425, p=0.008). Moreover, they showed a fair, positive correlation with 13C-GBT hourly dose at 30 min (rs=0.366, p=0.028), and a trend toward a positive correlation with the various MEGX test sampling times (MEGX15, rs=0.314, p=0.059; MEGX30, rs=0.284, p=0.088; and MEGX60, rs=0.320, p=0.059).

Conclusions: In this study we have shown that a progressive decline in liver function in patients with HCV-related CLD is paralleled by a decrease in Tpo production. The different correlations observed between Tpo and the various liver function tests suggests that this finding is mainly the result of a decrease in hepatic functional mass rather than dependent on alteration in splanchnic hemodynamic.