Thrombolysis is the breakdown (lysis) by pharmacological means, of blood clots. It is colloquially referred to as clot busting for this reason. It works by stimulating fibrinolysis by plasmin through infusion of analogs of tissue plasminogen activator, the protein that normally activates plasmin. Pharmacology (in Greek: pharmacon (φάρμακον) meaning drug, and logos (λόγος) meaning science) is the study of how substances interact with living organisms to produce a change in function. ... Thrombosis is the formation of a clot or thrombus inside a blood vessel, obstructing the flow of blood through the circulatory system. ... Fibrinolysis is the process where a fibrin clot, the product of coagulation, is broken down. ... Plasmin is an important degrading enzyme (EC 3. ... In blood coagulation, tissue plasminogen activator (tPA) is an enzyme (EC 3. ...

Agents

Thrombolysis requires the use of thrombolytic drugs, which are either derived from Streptomyces spp. or (more recently) the effect of recombinant technology, where human activators of plasminogen (e.g. tissue plasminogen activator, tPA) are manufactured by bacteria. Thrombolytic drugs are used in medicine to dissolve blood clots in a procedure termed thrombolysis. ... Recombinant proteins are proteins that are produced by different genetically modified organisms following insertion of the relevant DNA into their genome. ... Plasmin is an important degrading enzyme (EC 3. ... Phyla/Divisions Actinobacteria Aquificae Bacteroidetes/Chlorobi Chlamydiae/Verrucomicrobia Chloroflexi Chrysiogenetes Cyanobacteria Deferribacteres Deinococcus-Thermus Dictyoglomi Fibrobacteres/Acidobacteria Firmicutes Fusobacteria Gemmatimonadetes Nitrospirae Omnibacteria Planctomycetes Proteobacteria Spirochaetes Thermodesulfobacteria Thermomicrobia Thermotogae Bacteria (singular, bacterium) are a major group of living organisms. ...

Some commonly used thrombolytics are

• streptokinase
• urokinase
• alteplase (recombinant tissue plasminogen activator or rtPA).
• reteplase
• tenecteplase

Streptokinase is an extracellular metallo-enzyme produced by beta-haemolytic streptococcus and is used as an effective and cheap clot-dissolving medication in some cases of myocardial infarction (heart attack) and pulmonary embolism. ... Urokinase, also called urokinase-type Plasminogen Activator (uPA) is an enzyme (EC 3. ... In blood coagulation, tissue plasminogen activator (tPA) is an enzyme (EC 3. ... Reteplase (Retavase®) is a thrombolytic drug, used to treat heart attacks by breaking up the clots that cause them. ... Tenecteplase is an enzyme used as a thrombolytic drug. ...

Principles

Formation of blood clots lies at the basis of a number of serious diseases (see below). By breaking down the clot, the disease process can be arrested, or the complications reduced. While other anticoagulants (such as heparin) decrease the "growth" of a clot, thrombolytic agents actively reduce the size of the clot. An anticoagulant is a substance that prevents coagulation; that is, it stops blood from clotting. ... Heparin is a highly sulfated glycosaminoglycan widely used as an injectable anticoagulant. ...

All thrombolytic agents work by activating the enzyme plasminogen, which clears the cross-linked fibrin mesh (the backbone of a clot). This makes the clot soluble and subject to further proteolysis by other enzymes, and restores blood flow over occluded blood vessels. Plasmin is an important degrading enzyme (EC 3. ... Fibrin is a protein involved in the clotting of blood. ... Proteolysis is the directed degradation (digestion) of proteins by cellular enzymes called proteases or by intramolecular digestion. ... The arterial system The blood vessels are part of the circulatory system and function to transport blood throughout the body. ...

Uses

Diseases where thrombolysis is used:

• Myocardial infarction
• Cerebrovascular accident
• Massive pulmonary embolism
• Acute limb ischaemia

While the use of thrombolytic drugs can lyse an embolus to improve right ventricular function or pulmonary perfusion, it is also associated with an increased risk of major hemorrhage. The clinician should judge the use of this class of drugs on a case by case basis. Acute myocardial infarction (AMI or MI), commonly known as a heart attack, is a disease state that occurs when the blood supply to a part of the heart is interrupted. ... A stroke or cerebrovascular accident (CVA) occurs when the blood supply to a part of the brain is suddenly interrupted by occlusion (an ischemic stroke- approximately 90% of strokes), by hemorrhage (a hemorrhagic stroke - less than 10% of strokes) or other causes. ...

Contraindications

These are contraindicated in bleeding disorders, active bleeding and when there has been recent surgery. Diabetic retinopathy is a relative contraindication. Diabetic retinopathy is retinopathy (damage to the retina) caused by complications of diabetes mellitus, which could eventually lead to blindness. ...

References

• Wardlaw JM, Zoppo G, Yamaguchi T, Berge E (2003). "Thrombolysis for acute ischaemic stroke". Cochrane Database Syst Rev (3): CD000213. PMID 12917889.

Trivia

Tony Blair, in a speech, was unable to pronounce the word "thrombolysis". He responded to the laughter at his mistake with "and I'm the guy running the country."