Release of biologically active substances from non-aggregating human platelets

Area of Science:

• Biochemistry
• Hematology
• Pharmacology

Background:

• Human platelet-rich plasma (PRP) contains factors influencing vascular tone and platelet function.
• Spontaneous release of biologically active substances from platelets is a key area of research.

Purpose of the Study:

• To investigate the spontaneous release of anti-aggregatory and spasmogenic substances from human PRP.
• To identify the conditions and factors influencing the generation of these substances.

Main Methods:

• Incubation of human PRP at 37°C and comparison with room temperature/ice conditions.
• Extraction of active substances using ethyl acetate after acidification.
• Assessment of aspirin pretreatment effects (1h and 24h post-administration).
• In vitro incubation of PRP with non-steroidal anti-inflammatory drugs (NSAIDs).

Main Results:

• Human PRP spontaneously released an anti-aggregatory, spasmogenic substance upon incubation at 37°C.
• Activity was observed in platelets in aqueous solution but not in platelet-poor plasma.
• Aspirin pretreatment 1 hour before blood withdrawal reduced substance generation, but not 24 hours later.
• In vitro incubation with aspirin, indomethacin, or flurbiprofen did not affect production.

Conclusions:

• Non-aggregating human platelets generate a prostaglandin with both spasmogenic and anti-aggregatory properties.
• The generation of this substance is sensitive to in vivo aspirin administration but not direct in vitro incubation with NSAIDs.