Snail-derived compound prevents clots while preserving normal bleeding

For more than a century, heparin has been the go-to anticoagulant to prevent harmful blood clots in blood vessels or the heart from forming or getting larger. However, a major side effect is an increased risk of excessive bleeding, even from minor injuries like small cuts on the skin. In ACS Central Science, researchers report the discovery of a snail-derived compound that blocks clot formation while still preserving bleeding control in mouse models. 

Blood clots are natural temporary bandages that seal wounds and stop bleeding. These helpful clots - called hemostatic clots - speed healing to injuries like cuts to the skin. But a harmful type of clot called a thrombus can form inside blood vessels and the heart, blocking blood flow and causing severe pain and tissue damage. Deep vein thrombosis (DVT) occurs when these long-lasting clots form in the legs and don't dissolve like they should. If they break away and move to other parts of the body, thrombi can cause strokes, shortness of breath and possibly death. Although heparin and other blood thinners help prevent thrombi, these anticoagulants also interfere with normal clotting (hemostasis) and raise the risk of excessive bleeding. So, Mingyi Wu and colleagues looked for a safer, naturally occurring anticoagulant that only targets thrombus formation. 

After analyzing numerous mollusk compounds, the researchers identified CCG, a new glycosaminoglycan (a type of complex sugar) from the snail Camaena cicatricosa. Although part of CCG's molecular structure is similar to heparin, the sugar sequence that heparin uses to attach to one of its binding partners is missing in CCG. The researchers hypothesized that these differences could make CCG a safer anticoagulant. 

In tests with human plasma, CCG inhibited thrombus formation and had no effect on hemostasis. In mouse models of DVT, CCG administered by injection also reduced the incidence of thrombi DVT and, unlike heparin, did not increase bleeding risk. Further testing revealed that CCG prevents the assembly of an enzyme (iFXase) that is active in thrombus formation but not hemostasis. 

Although more research is needed, these initial results suggest that this snail-derived compound could be developed into a safer anticoagulant compared with heparins, the authors say.