Protamine-induced thrombocytopenia and leukopenia

Area of Science:

• Hematology
• Pharmacology

Background:

• Protamine is known to cause thrombocytopenia and granulocytopenia.
• The combined effect of protamine and heparin on these conditions requires further investigation.

Purpose of the Study:

• To examine the roles of protamine and heparin in causing thrombocytopenia and granulocytopenia.
• To investigate the dose-response relationship and mechanism of cell loss.

Main Methods:

• Administering protamine alone and sequentially with heparin to experimental animals.
• Utilizing 111In-labeled platelets for organ scanning.
• Incubating 125I-labeled protamine with blood cells in the presence of heparin.

Main Results:

• Protamine alone induced mild, transient granulocytopenia and thrombocytopenia.
• Sequential heparin-protamine administration caused more severe, prolonged cytopenia.
• Heparin-protamine complex formation and subsequent binding to platelets and granulocytes were observed.
• Transient accumulation of platelets in the lungs was noted post-infusion, without shortened platelet survival.

Conclusions:

• Protamine and heparin form a complex that binds to platelets and granulocytes.
• This complex leads to transient thrombocytopenia and granulocytopenia due to cell sequestration in the lungs.