High concentrations of thrombopoietin activate platelets in vitro

William P. Hammond, Theodore Wun, Alexander Kaplan, Svetlana Kaplan, Teresa Paglieroni, Kenneth Kaushansky, Donald C. Foster

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

Thrombopoietin (TPO), the ligand for the protooncogene c-mpl, has been cloned and expressed from both human and murine sources. Thrombopoietin increases platelet counts when given in vivo and acts on progenitor cells to increase their proliferation and maturation into megakaryocytes. The effects of TPO on mature platelets were investigated by evaluating platelet aggregation and platelet activation-dependent antigen expression. Platelet aggregation score, a quantitative representation of aggregation, showed potentiation of response to ADP-induced aggregation but no direct agonist response to TPO alone. Soluble c-mpl blocked the effect of TPO on the platelet aggregation score. Flow cytometry showed that TPO at concentrations >250 U/ml (50 ng/ml) caused a minority population of platelets to express the activation markers CD62, CD63 and activated glycoprotein IIb/IIIa. While stem cell factor and interleukins-3 and -6 did not affect platelet activation antigen expression, interleukin-11 increased CD62 expression on platelets in vitro. The effects of TPO on antigenic expression and aggregability were partially inhibited in vitro by preincubation with aspirin. We conclude that high concentrations of TPO promote platelet activation antigen expression on a proportion of platelets and potentiate platelet aggregability to ADP in vitro by a process that is partially inhibited by aspirin.

Original languageEnglish (US)
Pages (from-to)170-178
Number of pages9
JournalClinical and Applied Thrombosis/Hemostasis
Volume4
Issue number3
StatePublished - Jul 1998

Fingerprint

Thrombopoietin
Blood Platelets
Platelet Activation
Platelet Aggregation
Antigens
Adenosine Diphosphate
Aspirin
Interleukin-11
In Vitro Techniques
Platelet Glycoprotein GPIIb-IIIa Complex
Stem Cell Factor
Megakaryocytes
Interleukin-3
Platelet Count
Interleukin-6
Flow Cytometry
Stem Cells

Keywords

  • Platelet activation
  • Platelet aggregation
  • Thrombopoietin

ASJC Scopus subject areas

  • Hematology

Cite this

Hammond, W. P., Wun, T., Kaplan, A., Kaplan, S., Paglieroni, T., Kaushansky, K., & Foster, D. C. (1998). High concentrations of thrombopoietin activate platelets in vitro. Clinical and Applied Thrombosis/Hemostasis, 4(3), 170-178.

High concentrations of thrombopoietin activate platelets in vitro. / Hammond, William P.; Wun, Theodore; Kaplan, Alexander; Kaplan, Svetlana; Paglieroni, Teresa; Kaushansky, Kenneth; Foster, Donald C.

In: Clinical and Applied Thrombosis/Hemostasis, Vol. 4, No. 3, 07.1998, p. 170-178.

Research output: Contribution to journalArticle

Hammond, WP, Wun, T, Kaplan, A, Kaplan, S, Paglieroni, T, Kaushansky, K & Foster, DC 1998, 'High concentrations of thrombopoietin activate platelets in vitro', Clinical and Applied Thrombosis/Hemostasis, vol. 4, no. 3, pp. 170-178.
Hammond WP, Wun T, Kaplan A, Kaplan S, Paglieroni T, Kaushansky K et al. High concentrations of thrombopoietin activate platelets in vitro. Clinical and Applied Thrombosis/Hemostasis. 1998 Jul;4(3):170-178.
Hammond, William P. ; Wun, Theodore ; Kaplan, Alexander ; Kaplan, Svetlana ; Paglieroni, Teresa ; Kaushansky, Kenneth ; Foster, Donald C. / High concentrations of thrombopoietin activate platelets in vitro. In: Clinical and Applied Thrombosis/Hemostasis. 1998 ; Vol. 4, No. 3. pp. 170-178.
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