Polysulfated trehalose as a novel anticoagulant agent with dual mode of action

Abstract

Physiological hemostatic balance is a coordinated outcome of counteracting coagulation and fibrinolytic systems. An imbalance of procoagulant and anticoagulant factors may result in life threatening thromboembolism. Presently, anticoagulant administration is the first line of therapy for the treatment of these conditions and several anticoagulants have been approved, including various forms of heparin. However, the polyanionic nature and multispecificity of heparin pose several complications. Generally, the polysulfated compounds with antithrombotic potential are thought to have feasible synthetic procedures with much less bleeding, thus having favourable safety profiles. Here we report the synthesis of a novel compound, trehalose octasulfate and the assessment of its anticoagulation potential. Molecular docking of trehalose and trehalose octasulfate with antithrombin showed a specificity switch in binding affinity on sulfation, where trehalose octasulfate interacts with critical residues of AT that are either directly involved in heparin binding or in the conformational rearrangement of AT on heparin binding. An in vitro analysis of trehalose octasulfate demonstrated prolonged clotting time. Lead compound when intravenously injected in occlusion induced thrombotic rats showed remarkable reduction in the size and weight of the clot at a low dose. Delay in coagulation time was observed by analysing blood plasma isolated from rats preinjected with trehalose octasulfate. A decrease in Adenosine 5'-Diphosphate (ADP) induced platelet aggregation indicated a probable dual anticoagulant and antiplatelet mechanism of action. To summarize, this study presents trehalose octasulfate as a novel, effective, dual acting antithrombotic agent.

Scheme 1

Figure 1

Ligplot analysis of binding of trehalose and trehalose octasulfate to antithrombin (1E05) heparin cofactor II (1JMJ).

Figure 2

Effect of trehalose on clotting assays (a) APTT, (b) PT and (c) TT using human pooled plasma, expressed as ratio of clotting time in the presence and absence of trehalose octasulfate. Values represent an average of three independent experiments.

Figure 3

Effect of trehalose octasulfate on clotting assays (a) APTT, (b) PT and (c) TT using human pooled plasma, expressed as ratio of clotting time in the presence and absence of trehalose. Values represent an average of three independent experiments.

Figure 4

Comparison of thrombi harvested from control, trehalose and trehalose octasulfate treated thrombosis model animals.

Figure 5

Comparison of thrombi from control, trehalose and trehalose octasulfate treated thrombosis model animals; (a) weight, (b) length, and (c) weight/length ratio of the thrombus formed inside the ligated IVC.

Figure 6

Effect of trehalose and trehalose octasulfate on (a) APTT and (b) PT in rat plasma after IV infusion of the compounds.

Figure 7

Effect of trehalose octasulfate on platelet aggregation, in whole blood of rat injected with the compounds, P < 0.05.