i(3)so3-galactosylceramide and Thrombosis

In 1961, Wago et al. reported a potential anticoagulant role for sulfatide using animal experiments. Since then there have been many studies of sulfatide in the field of thrombogenesis/haemostasis, yielding contradictory conclusions. Some report that sulfatide has anti-thrombotic activity because it prolongs clotting time, inhibits platelet adhesion, and prolongs bleeding. Others report that sulfatide induces thrombosis in animal models. This mini-review is a chronologic review of reports examining the role of sulfatide in thrombogenesis/haemostasis together with the introduction of data from our laboratory and a discussion of the possible mechanisms underlying these curious phenomena.

Topics: Animals; Anticoagulants; Blood Coagulation; Disease Models, Animal; Hemostasis; Humans; Platelet Adhesiveness; Sulfoglycosphingolipids; Thrombosis; Venous Thrombosis

Sulfatide (galactocylceramide-3'-sulfate), a cell surface glycosphingolipid interacts with several cell adhesion molecules including fibrinogen, von Willebrand factor (VWF), P-selectin, thrombospondin (TSP) and laminin, which are involved in haemostasis. We have used a sulfatide-specific single-chain fragment variable (scFv) antibody probe PA38 and sulfatide-deficient mice to investigate the role of membrane sulfatide in platelet function. PA38 bound to platelets and binding increased following platelet activation. Sulfatide was localized as a large cluster towards the center of the platelet surface when examined in a confocal microscope. PA38 (20 microg/ml) inhibited the adhesion of activated platelets to fibrinogen, VWF, P-selectin, TSP1 and laminin by 30%, 30%, 75%, 20% and 35%, respectively, compared to a control scFv (p < 0.05). Furthermore, PA38 inhibited collagen, ADP, thrombin and ristocetin-induced platelet aggregation in PRP by 25%, 30%, 18% and 20%, respectively, compared to the control scFv (p < 0.05). In a PFA-100 platelet function assay, PA38 prolonged the occlusion time by 25% (p < 0.05). Under flow PA38 decreased the thrombus formation on collagen by 31%, (p < 0.01). Sulfatide-deficient mice displayed an extended lag-phase in collagen-induced platelet aggregation compared to wild type (p < 0.05), though in-vivo haemostasis did not differ significantly. Thus, this study provides new evidence for a role for membrane sulfatide in platelet function.

Topics: Animals; Blood Platelets; Cell Membrane; Cerebroside-Sulfatase; Disease Models, Animal; Hemorheology; Hemostasis; Humans; Immunoglobulin Variable Region; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Platelet Adhesiveness; Platelet Aggregation; Platelet Function Tests; Sulfoglycosphingolipids; Thrombosis

Sulfatides are sulfated glycosphingolipids present on the surface of a variety of cells; however, their exact physiological function is not known. Recently, we have shown that the inhibition of sulfatide-P-selectin interactions leads to disaggregation of platelet aggregates.. In this study, we show that sulfatides activated platelets as they increased activation of GPIIb/IIIa (PAC-1 epitope) and expression of P-selectin on the platelet surface. Furthermore, sulfatides aggregated washed platelets in a dose-dependent manner and enhanced platelet aggregation in platelet-rich plasma. Previous activation of platelets was necessary for this effect. Monoclonal anti-P-selectin antibodies inhibited not only sulfatide-induced PAC-1 binding to platelets but also sulfatide-induced platelet aggregation, suggesting that sulfatides activate platelet GPIIb/IIIa via signaling through P-selectin. The proaggegatory effect of sulfatides was also observed in an ex vivo thrombosis model using whole blood and pulsatile flow at 37 degrees C. In this model, sulfatides significantly enhanced platelet aggregation and the formation of platelet-leukocyte aggregates.. We show that sulfatide-P-selectin interactions lead to subsequent platelet activation and P-selectin expression, forming a positive feedback loop that can potentiate formation of stable platelet aggregates. In addition, sulfatides enhance the aggregation of platelet-leukocyte aggregates. These mechanisms may play a significant role in hemostasis and thrombosis.

Topics: Adenosine Diphosphate; Blood Platelets; Cell Aggregation; Gene Expression Regulation; Humans; Leukocytes; P-Selectin; Platelet Activation; Platelet Aggregation; Platelet Function Tests; Sulfoglycosphingolipids; Thrombosis

It has long been controversial whether sulfatide stimulates blood coagulation or inhibits blood coagulation. In this paper, I demonstrated not only anticoagulant activity but also coagulant activity of sulfatide in vivo by using experimental animal models and presented the possibility that sulfatide may function contradictorily under physiological and/or pathological conditions. For instance, I presented possible involvement of sulfatide in thrombotic diseases associated with cancers.

Topics: Animals; Anticoagulants; Blood Coagulation; Coagulants; Factor XII; Humans; In Vitro Techniques; Mice; Neoplasms; Rats; Sulfoglycosphingolipids; Thrombosis

In an attempt to explore a novel therapeutic approach, a new synthetic sulfatide derivative (SKK60037) was evaluated in an acute rat model of P-selectin and leukocyte-dependent thrombotic glomerulonephritis (TG). In vitro, SKK60037 inhibits the function of P- and L-selectin more effectively than sialyl Lewis X (sLe(x)), a well-established selectin blocker. TG was induced by the intravenous administration of nephrotoxic globulin (NTG) to rats pretreated with a subclinical dose of lipopolysaccharide. In this model, platelet accumulation was remarkable within 10 minutes after induction of disease, followed by the infiltration of leukocytes, mainly neutrophils and macrophages. Thrombus formation and fibrinogen deposition in the glomeruli were observed within 1 hour, and they proceeded until 6 hours. P-selectin was highly expressed in glomeruli, whereas E-selectin and L-selectin ligands were not detected. We tested the effects of SKK60037 in this model in comparison with sLe(x) and antirat P-selectin monoclonal antibody (ARP2-4). SKK60037 blocked platelet accumulation in glomerular capillaries at 10 minutes after NTG injection. At 6 hours, leukocyte infiltration and thrombosis were significantly suppressed. Protective effects of SKK60037 were similar to those of ARP2-4, whereas sLe(x) showed minimum effect. The superior effects and more favorable characteristics of SKK60037 to sLe(x) suggest the potential of SKK60037 for clinical application.

Topics: Animals; Cell Adhesion Molecules; Female; Globulins; Glomerulonephritis; Kidney; Kidney Glomerulus; Lipopolysaccharides; Oligosaccharides; Rats; Rats, Wistar; Selectins; Sialyl Lewis X Antigen; Sulfoglycosphingolipids; Thrombosis

The mechanism of anticoagulant activity of sulfatide (galactosylceramide I3-sulfate), which exists in serum lipoproteins of various mammals except rodents, was investigated, together with the pharmacological effects of the glycolipid on the blood coagulation system in rabbits. The sulfatide was shown to be an effective anticoagulant when it was added in vitro in the form of pure micelle without auxiliary lipids such as phosphatidylcholine and/or cholesterol. The anticoagulant activity of synthetic galactosylceramide I6-sulfate, a positional isomer with respect to the sulfate group, was stronger than that of the sulfatide. The anticoagulant activity was specifically inhibited by anti-sulfatide antibody. The study on the pharmacological effects of sulfatide showed that the fibrin-precipitation time after single injection of the lipid (10 mg/kg body weight) into rabbits increased 2.5-fold compared with the normal level, and the maximum effect was observed 1 h after the injection. The half-life of anticoagulant activity was 5 h. These results suggest that sulfatide may be effective for the prevention of thrombosis. Sulfatide may be safer than other anticoagulant drugs, because it is a natural component of serum lipoproteins. Further, it may well play an essential role as an endogenous anticoagulant in mammals. Unlike heparin, sulfatide failed to inhibit thrombin and coagulation factor Xa activities in the presence of antithrombin III, indicating that the anticoagulant mechanism of sulfatide is independent of antithrombin III. These results indicate that the anticoagulant activity of sulfatide is potent and specific, and the lipid may be available as a useful and safe antithrombotic drug.

Topics: Animals; Anticoagulants; Antithrombin III; Blood Coagulation; Cholesterol; Drug Evaluation, Preclinical; Factor Xa Inhibitors; In Vitro Techniques; Phosphatidylcholines; Rabbits; Sulfoglycosphingolipids; Thrombin; Thrombosis