Human platelet storage organelles. A review

Area of Science:

• Hematology
• Cell Biology

Background:

• Platelets contain various electron-dense subcellular organelles, including alpha-granules and dense bodies.
• These organelles are primarily secretory granules, releasing their contents upon stimulation.

Purpose of the Study:

• To review the literature on the localization of secreted substances within specific platelet organelles.
• To consolidate findings on the types and functions of platelet storage organelles.

Main Methods:

• Electron microscopy and microprobe analysis.
• Selective secretion experiments.
• Subcellular fractionation and studies on storage pool deficient platelets.

Main Results:

• Platelets contain at least four distinct types of storage organelles.
• Specific substances like serotonin, ATP, ADP, calcium, and growth factors are stored and secreted.
• Evidence supports the role of these organelles in platelet secretion.

Conclusions:

• Human platelets possess a complex system of at least four types of storage organelles.
• Understanding these organelles is crucial for comprehending platelet function and secretion.