OBJECTIVETo investigate the antithrombotic mechanisms of holothurian glycosaminoglycan (GAG) extracted from sea cucumber.

METHODSHuman endothelial cell line EA. hy926 cells were treated with 10 mg/L GAG or 10U/mL unfractionated heparin (UFH) by short-term (15 min - 2 h) and longer-time incubation (6 h - 48 h). Different doses of GAG were used to stimulate EA. hy926. Released free tissue factor pathway inhibitor(TFPI) was determined by ELISA assay. TFPI expression was investigated by immunofluorescent method and TFPI mRNA level by real-time PCR. In a 96-wells microtitre plate, pooled normal plasma containing different concentrations of GAG was allowed to clot by addition of thrombin and calcium chloride, fibrinolysis was induced by addition of t-PA. TRR (TAFI-related retardation of clot lysis) was used to assess thrombin-activatable fibrinolysis inhibitor(TAFI) functional activity.

RESULTSGAG increased TFPI synthesis, expression and secretion in a dose- and time dependent manner. GAG at low concentrations could lengthen while at intermediate concentrations could shorten clot lysis times significantly as compared to control values. TRR was dose-dependently decreased on addition of GAG.

CONCLUSIONSGAG increases TFPI synthesis, expression and secretion of endothelial cells. GAG at intermediate concentrations significantly affects clot stability of a developing clot by means of diminishing TAFI activation.