Abstract
In vitro studies have described the sulfated agaran from Acanthophora muscoides as an intrinsic inhibitor of thrombin generation (TG), but not in ex vivo assay. This investigation partially characterized a pyruvate fraction with in vitro and ex vivo effects on an intrinsic/extrinsic pathway-induced thrombin generation (TG) continuous model using 36 or 60-fold diluted mice or defibrinated, normal human plasma. Fraction separated by DEAE-cellulose chromatography exhibited charge homogeneity and non-sulfated polysaccharides (<100 kDa) by agarose and polyacrylamide gel electrophoresis, respectively, using Stains-all alone. Fourier Transform Infrared and Nuclear Magnetic Resonance studies indicated a 4,6-pyruvated agaran-structure. The fraction and heparin had no effect on prothrombin time, but there was a preponderant intrinsic rather than extrinsic pathway inhibition in TG assay; themselves, acting on both free and fibrin bound thrombin activity without chromogenic substrate interaction. Both fractions, desulfated and native, anticipated and induced thrombin formation in activators-devoid or normal plasma. In addition, mice pretreated with fraction (20 mg kg-1, intraperitoneally) reduced intrinsically plasma TG ex vivo after 2h. Heparin suppressed TG in vitro, but induced it ex vivo. Therefore, agaran from A. muscoides blocks TG on in vitro and ex vivo studies, suggesting to evaluate the blood coagulability status.
Highlights
Blood coagulation is a complex reaction involving plasma factors that circulate in an inactive form until proteolytic activation by an upstream factor, and thrombin is the major effector for clot formation
Thrombin has pro- and anticoagulant roles connected to coagulation factors and inhibitors, such as antithrombin on protease regulation, an amino acid glycoprotein produced in the liver (Rau et al, 2007), which has unfractionated heparin (UHEP) as its cofactor due to the unique pentasaccharide sequence with high affinity binding to antithrombin displaying in vitro and in vivo effects (Nader et al, 2001)
>100 kDa Origin revealed sulfated polysaccharides (SPs)-Am as asingle band exhibiting strong metachromasy migrating to dermatan sulfate (Figure 1Aa), + AA whereas the polyacrylamide analysis indicated a distinct profile from standard glycosaminoglycans on gel, which was because the high molecular size SP-Am (> 100 kDa) revealed concentrated in the origin (Figure 1Ba)
Summary
Blood coagulation is a complex reaction involving plasma factors that circulate in an inactive form until proteolytic activation by an upstream factor, and thrombin is the major effector for clot formation. Thrombin is generated by the tissue factor-dependent extrinsic pathway and the contact factor-dependent intrinsic pathway (Rau, Beaulieu, Huntington, & Church, 2007), which are analyzed by prothrombin time (PT) and activated partial thromboplastin time tests, respectively. These tests do not accurately prove the amplification and propagation steps of hemostasis.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
