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In vivo platelet production from mature megakaryocytes: does platelet release occur via proplatelets?

Goro Kosaki1

  • 1Surgery II, Osaka University Medical School, Japan.

International Journal of Hematology
|April 9, 2005
PubMed

Insights

Platelet formation from megakaryocytes (MKs) may occur via explosive fragmentation, not solely through proplatelet processes. This review proposes a "protoplatelet" concept and discusses the lungs' role in platelet production.

Area of Science:

  • Hematology
  • Cell Biology
  • Biophysics

Background:

  • Platelet production is essential for hemostasis.
  • The precise in vivo mechanism of platelet release from megakaryocytes (MKs) is debated.
  • The proplatelet formation (PPF) theory is widely accepted but questioned.

Purpose of the Study:

  • To review and critically evaluate current theories of platelet formation.
  • To present evidence supporting explosive MK cytoplasm fragmentation.
  • To introduce a novel "protoplatelet" concept and discuss the lung's role in platelet production.

Main Methods:

  • Review of existing literature, including in vitro and in vivo studies.
  • Analysis of transmission electron microscopy (TEM) and scanning electron microscopy (SEM) data.
  • Phase-contrast microscopy observations of MKs.

Main Results:

  • Evidence suggests platelet formation occurs via explosive fragmentation of MK cytoplasm, not exclusively through PPF.
  • PPF may not be a prerequisite for physiological platelet release.
  • The lungs may play a significant role in platelet production.

Conclusions:

  • Explosive fragmentation is a plausible mechanism for platelet formation.
  • "Protoplatelet" concept offers an alternative framework.
  • Further research is needed to elucidate the complete process and the lung's contribution.

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