The effect of the secretory phospholipases A2 from Gloydius blomhoffii and Gloydius halys venoms on hemostasis components in vitro

The aim of this study was to investigate the effects of Gloydius blomhoffii and Gloydius halys venoms and their fractions on platelet and plasma hemostasis, and to evaluate the ability of the sPLA2 inhibitor Varespladib to neutralize the coagulopathic activity mediated by secretory phospholipase A2 (sPLA2) present in these venoms. The proaggregatory effect of whole G. halys and G. blomhoffii venoms on platelet hemostasis was associated with multidirectional effects of their multiple protein components, while sPLA2-containing fractions exhibited an antiaggregatory effect. Whole G. halys and G. blomhoffii venoms and Varespladib added to them did not affect the extrinsic pathway of hemocoagulation, but inhibited the intrinsic pathway of human blood coagulation. The paradoxical effect of further enhancing the anticoagulant activity of G. halys and G. blomhoffii venoms with the sPLA2 inhibitor Varespladib could be determined by a stronger sPLA2 interaction with blood coagulation factor Xa after formation of the enzyme-inhibitor complex.