Baseline levels of thrombopoietin were undetectable in 39 of 43 patients with cirrhosis. In patients who had orthotopic liver transplantation, the mean interval to first detection of thrombopoietin was about 3 days and peak levels occurred about 8 days after transplantation. Platelet counts increased during or immediately after peak concentrations of thrombopoietin. A representative graph of thrombopoietin levels and platelet counts in 1 patient who had orthotopic liver transplantation is shown in the Figure . Results are expressed as ratios to control for the number of liver cells.
Receptors have the ability to bind, internalize, and degrade thrombopoietin.
Elevated levels of thrombopoietin then stimulate megakaryopoiesis and platelet production. This model establishes an inverse relation between thrombopoietin levels and platelet counts. On the basis of this model, we expected elevated levels of thrombopoietin in cirrhotic patients who had thrombocytopenia. On the contrary, we found low or undetectable levels, which suggests that thrombopoietin levels and platelet counts are not inversely related in patients with cirrhosis. Several explanations m ay account for this.