assistant professor Asahikawa Medical University Asahikawa, Hokkaido, Japan
Background: Hypothermia triggers coagulation disorders, which can lead to the development of life-threatening diseases in various organs. We previously reported that hypothermia induced platelet activation in the spleen, which resulted in microthrombosis after rewarming. However, the changes in whole blood clotting properties that occur in diseased states remain unclear.
Aims: Using thromboelastography, we investigated blood clotting activity and the effects of rewarming in a hypothermia-induced mouse model.
Methods: C57Bl/6 mice were placed at -20°C under general anesthesia until their rectal temperature decreased to 15°C. One group of mice was kept at 4°C for 2 hours and then euthanized. Another group was rewarmed, kept in normal conditions for 24 hours, and then euthanized. Tissue and citrated whole blood samples were obtained from the mice for histopathological analysis, flow cytometry, and thromboelastography.
Results: Hypothermia induced the activation of platelets in the spleen; however, rewarming significantly reduced the number of activated platelets. Rewarming significantly increased the number of activated platelets in the peripheral blood, whereas no increase was observed in the hypothermia model. Thromboelastography analysis showed that whole blood samples from the rewarmed mice displayed an enhanced clotting strength.
Conclusion(s): Rewarming from hypothermia enhances whole blood coagulation activity due to an increase in the number of active platelets in peripheral blood. This phenomenon may lead to thrombotic disorders.