esearchers at the Institute for Cardiovascular and Metabolic Research (ICMR) at the University of Reading, have discovered the mechanism by which platelets bind together to form blood clots. This discovery, they say, can lay the foundation for new treatments to prevent stroke or heart attacks.
In healthy people, blood is always in a physiological fluid-coagulant equilibrium. In other words, when the endothelium is damaged, platelets and fibrinogen form a network plug that repair the defect and the bleeding stops. Then the network of fibrin is lysed and the blood vessel is recanalized. This process occurs continuously in the body. In certain diseases or conditions such hypercoagulability or atrial fibrillation, platelets aggregate together to form a thrombus that may obstruct imporant blood vessels. What researchers found is how platelets communicate with each other. It seems that platelets are interconnected by gap junctions, some pore-like structures. ‘Gap junction’ is a common type of connection to other cells, such as myocardial cells or neurons. Gap junctions are a special type of connection that interconnects the cytoplasm of two cells.
Professor Jonathan Gibbins and Dr. Sakthivel Vaiyapuri, said: “This appears to be a very important communication mechanism for blood clotting and thrombosis”. He added that by blocking those channels involved in the formation of junctions thrombosis can be reduced. The new discovery may be a target in antithrombotic therapy.
Currently, stroke is prevented by oral anticoagulant medication (warfarin) which inhibits the synthesis of coagulation factors dependent on vitamin K. This medication has several drawbacks. On the one hand, and patient dose should be adjusted by measuring the INR (International Normalised Ratio), on the other hand, there are plenty of side effects. Oral anticoagulants can cause bleeding and give drug interactions. It is important to note that the risk of bleeding is significantly increased when combined with anticoagulants such as clopidogrel antiplatelet or aspirin. In addition to this, anticoagulants are prohibited during pregnancy.
Anticoagulant medication is commonly prescribed in patients with cardiovascular disorders. Oral anticoagulants are prescribed long-term in patients with atrial fibrillation to prevent thromboembolic accidents. Because atria no longer contract, blood tends to clot and the formed thrombi can migrate into circulation and stroke can occur. Also, patients with metal valves need to follow long-term treatment with oral anticoagulants to prevent thrombosis.
Understanding the mechanisms underlying thrombosis may be a target for discovery of new anticoagulants. Dr. Vaiyapuri notes that this discovery is exciting even if their work is still not complete.