Activation of circulating platelets by hyperthermal stress

Area of Science:

• Cardiovascular Biology
• Hematology
• Therapeutic Hot Springs Research

Background:

• Frequent thrombosis is observed following hot-spring bathing.
• Platelet activation is a key factor in thrombosis.
• The impact of hyperthermal stress from hot springs on platelet activation is not well understood.

Purpose of the Study:

• To investigate the effect of hyperthermal stress from hot-spring bathing on platelet activation in vivo.
• To determine if hot-spring bathing induces platelet granule release.

Main Methods:

• Human subjects underwent traditional 47°C hot-spring bathing.
• Plasma levels of beta-thromboglobulin (beta-TG) and platelet factor 4 were measured at intervals.
• A control group experienced a 42°C bath.
• The ratio of beta-TG to platelet factor 4 was used to assess in vivo versus in vitro activation.

Main Results:

• Plasma beta-TG levels significantly increased 10 minutes after starting the 47°C bath.
• No significant change in plasma beta-TG was observed during the 42°C control bath.
• The beta-TG to platelet factor 4 ratio indicated minimal artificial platelet activation during the study.

Conclusions:

• Hyperthermal stress from hot-spring bathing at 47°C can induce platelet granule release in vivo.
• Even short exposure to high temperatures in hot springs activates platelets.
• These findings suggest a mechanism linking hot-spring bathing to increased thrombosis risk.