Modulation of hyperthermia-induced platelet aggregation inhibition in the presence of urea

Purpose: This study has been conducted to evaluate the effect of urea on aggregation responses of heat-treated platelets. Materials and methods: The urea was added to platelet-rich plasma (PRP) samples in final concentrations of 50 and 100 mM. PRP samples, with or without exogenous urea, were incubated at 37 degrees C, 39 degrees C and 41 degrees C for 90 min and then were stimulated with adenosine diphosphate (ADP) or epinephrine for measuring of platelet aggregation responses. The average reduction in aggregability of heat-treated samples with reference to mean value obtained for control samples treated at 37 degrees C was expressed as inhibition percentage. Results: Aggregation responses of the samples treated in the presence of 50 mM and 100 mM urea were significantly less inhibited by hyperthermia treatments compared with those treated without exogenous urea. Conclusion: The results indicate that the inhibitory effect of hyperthermia on platelet aggregation responses could be significantly modulated by urea.