1- Haemostatic Mechanism3

Thrombopoietin (TPO)
is the major regulator of platelet formation and 95% is produced
by the liver. Approximately 50% is produced constitutively the
plasma level depending on its removal from plasma by binding to c‐
MPL receptors on platelets and megakaryocytes. Therefore, levels
are high in thrombocytopenia as a result of marrow aplasia but low
in patients with raised platelet counts. The other 50% is regulated in
response to platelet destruction. As platelets age they lose surface
sialic acid. This exposes galactose residues that attach to the
Ashwell–Morell receptor in the liver.