Induction of monocytic tissue factor expression after rewarming from hypothermia in vivo is counteracted by heat shock in c-Jun-dependent manner.

Objective: Triggering of tissue factor (TF)-mediated blood coagulation leads to the development of disseminated intravascular coagulation during rewarming from hypothermia. We studied post-rewarming TF levels, activity, and surface redistribution, along with the regulation of TF gene transcription in mononuclear cells (MNCs) obtained from an in vivo rat model.

Methods And Results: Rewarming after a 5-hour episode of 15 degrees C hypothermia caused an increase in TF activity, protein levels, and externalization of TF antigen in rat MNCs. This was accompanied by a dramatic elevation of c-Jun and JNK phosphorylation, and the absence of EGR-1 and NF-kappaB activation. To search for a stimulus to counteract c-Jun-mediated induction of TF activity in MNCs from rewarmed rats, we applied heat shock pretreatment one day before the hypothermia/rewarming experiment. This restored post-rewarming TF activity, protein levels, and surface-to-total TF ratio in rat MNCs to normothermic levels. Furthermore, in heat shock-pretreated animals, rewarming failed to increase phosphorylated c-Jun and JNK levels. We attribute this to the profound overexpression of heat shock protein 70 and inhibition of JNK.

Conclusions: MNCs respond to rewarming from hypothermia by an induction of active TF antigen. This effect is dependent on c-Jun activation and is abolished by heat shock pretreatment.