Thrombocytopenia is a primary manifestation of immune thrombocytopenic purpura (ITP) and may occur as a result of hepatitis C, malignancy, and treatment with chemotherapy. There is a need for additional means to treat thrombocytopenia in these settings. Recombinant thrombopoietin-like agents became available after the cloning of thrombopoietin in 1994. In clinical trials, these agents showed so...

Patients with myeloproliferative disorders (MPDs), such as essential thrombocythemia (ET) have increased risk of thrombosis and bleeding, which are major sources of morbidity and mortality. Most MPD patients have a gain of function mutation in Janus kinase 2 (JAK2V617F), but little is known how JAK2V617F affects platelet function. Here, we demonstrate that platelets from ET patients have impair...

Although myelodysplastic syndromes are heterogeneous disorders comprising a benign subset of bone marrow failure similar to aplastic anemia, no laboratory test has been established to distinguish it from bone marrow failures that can evolve into acute myeloid leukemia. Plasma thrombopoietin levels were measured in 120 patients who had myelodysplastic syndrome with thrombocytopenia (< 100 × 10(9...

Thrombocytopenia (platelet count <150 × 10(9)/L) often complicates chronic liver disease, impeding optimal management of these patients. The prevalence of this manifestation ranges from 6% among non-cirrhotic patients with chronic liver disease to 70% among patients with liver cirrhosis. It has also been shown that the severity of liver disease is associated with both prevalence and level of th...

Partially purified thrombopoiesis-stimulating activity was prepared from the plasma of thrombocytopenic rabbits using ammonium sulfate precipitation and DEAE cellulose, Sephadex, and carboxymethyl cellulose chromatography. The protein fraction precipitated by an ammonium sulfate saturation of 60%-80%, previously shown to contain thrombopoiesis-stimulating activity, was used as starting material...

OBJECTIVE We previously determined that protein kinase C δ (PKCδ) regulates platelet function. However, the function of PKCδ in megakaryopoiesis is unknown. APPROACH AND RESULTS Using PKCδ(-/-) and wild-type littermate mice, we found that deficiency of PKCδ caused an increase in white blood cells and platelet counts, as well as in bone marrow and splenic megakaryocytes (P<0.05). Additionally,...

and our studies have demonstrated that a recombinant thrombopoietin might also be of benefit.3,4 Exposing healthy donors to hematopoietic growth factors has long been controversial, as has the concept of exposing donors to apheresis devices themselves. Donors have recently been asked to increase their donation of a variety of apheresis products (platelets, granulocytes, red cells, plasma) and p...

BACKGROUND AND OBJECTIVE Thrombopoietin has been established as the major regulator of megakaryocyte and platelet production. In this study we evaluated the effects of PEG-recombinant human megakaryocyte growth and development factor (PEG-rHuMGDF), a pegylated and truncated form of thrombopoietin, on the growth and differentiation of the HEL cell line. As a model system we chose the pluripotent...

OBJECTIVE To observe thrombopoietin (TPO) levels in patients with non-alcoholic fatty liver disease (NAFLD). METHODS The study was performed between November 2010 and March 2011 at the Department of Internal Medicine, Faculty of Medicine, Fatih University, Ankara, Turkey. A total of 60 consecutive patients with ultrasound proven NAFLD (study group), and 28 healthy volunteers (control study) ...

Thrombopoietin (TPO) is the major physiological regulator of platelet production. TPO binds the TPO receptor, activates JAK and STAT pathways, thus stimulating megakaryocyte growth and platelet production. There is no "sensor" of the platelet count; rather TPO is produced in the liver at a constant rate and cleared by TPO receptors on platelets. TPO levels are inversely proportional to the rate...