Aims: 

Neutrophils were reported to take part in promoting the activation of the coagulation cascade by uptake of tissue-factor (TF) bearing microvesicles. Exposition of phosphatidylserine (PSE) is an essential cofactor of TF, which had been reported to be reduced in human monocytes by the KATP-channel blocker glibenclamide (GLIB). We tested the hypothesis, that GLIB might reduce PSE in neutrophils, too.

Methods: 

Tightly closed vacuum tubes filled with whole heparinised venous blood of male healthy volunteers were incubated at 37°C in a shaking water bath for 0, 2, or 8 hours in absence and presence of 30mM GLIB. PSE was quantified using flow cytometry by staining with annexinV-FITC and counterstaining with CD14-PerCP in order to exclude monocytes. Neutrophils were gated on basis of forward and side scatter and mean annexin-V-FITC fluorescence was evaluated.

Results: 

PSE of neutrophils significantly increased within 2 hours and to about 6 times after 8 hours of ex-vivo incubation. GLIB strongly reduced PSE both after 2 and 8 hours.

Conclusion: 

PSE on neutrophils arose during ex-vivo incubation of whole blood in a time dependent way. This process, which accompanies neutrophils apoptosis, necrosis and activation of coagulation could be dramatically retarded by glibenclamide. This finding might suggest a role for KATP-channels in neutrophils in mediating "blood-borne" thrombosis as it is part of the mechanisms of stasis-induced coagulation.