Heparin is a sulfated nature glycosaminoglycan of mixed composition, released by mast cells and by blood basophiles in many tissues of human body and mammal body, and having potent anticoagulant properties, existing in the form of proteoglycan unit, and its chemical structure formed by connection of D-glucopyranuronic acid and D-glucosamine by turns, molecular weight distribution 5000~30000, average molecular weight 20000.
Clinical heparin is obtained from the mucosa of small intestine of porcine origin by purification, usually in the form of heparin sodium and heparin calcium, mainly heparin sodium.
Heparin has potent anticoagulant and antithrombotic properties, i.e. inhibiting Xa and IIa. Heparin binds to the enzyme inhibitor antithrombin III (ATIII) causing a conformational change that result in its activation through an increase in the flexibility of its reactive site loop. The activated AT then inactivates thrombin and other proteases involved in blood clotting, most notably factor Xa. So it can be used in both of inside and outside body. Except for its anticoagulant and antithrombotic properties, heparin also has a lot of biological functions such as hypolipidemic, anti- atherosclerosis, anti-smooth muscle cells proliferation(SMC), antiphlogistic, antianaphylaxis, anti-virus and anticancer etc.. So heparin is used widely in medicine and also has well therapeutic effectiveness to many diseases. Excepting for directly using in clinical hypolipidemic and anti- atherosclerosis, heparin also is the raw material for producing low molecular weight heparin and the kinds of heparin derivative medicine.
Heparin can be used for:
1. Prevention of thrombus: during those surgical operation such as displacement of hip joint, knee joint and percutaneous coronary intervention (PCI), heparin can be used to prevent thrombus mainly including deep venous thrombosis and lung thrombosis;
2. Prevention and treatment of thrombotic disease: such as miocardial infarction, unstable angina and apoplexy and so on.
3. Treatment of disseminated intravascular coagulation (DIC) caused by all kinds diseases.
4. Anticoagulant outside body: hematodialysis, blood bank, extracorporeal circulation, blood sample and intravascular stent and so on.