The key difference between thrombolysis and fibrinolysis is that thrombolysis is the dissolution of thrombus (blood clot) due to various chemical and physical agents, while fibrinolysis is the breakdown of fibrin in the blood clots due to natural processes or various chemical agents.
Thrombosis is the formation of blood clots inside blood vessels. It obstructs the transportation of blood through the circulatory system. Normally, when a blood vessel is injured, the body uses platelets and fibrin to form a blood clot to prevent excessive blood loss. Even when a blood vessel is not injured, blood clots may form in the body under certain conditions. Unnecessary blockage of blood flow due to blood clots can cause various diseases, including strokes. Thrombolysis and fibrinolysis are two mechanisms used to break down blood clots.
CONTENTS
1. Overview and Key Difference
2. What is Thrombolysis
3. What is Fibrinolysis
4. Similarities – Thrombolysis and Fibrinolysis
5. Thrombolysis vs Fibrinolysis in Tabular Form
6. Summary – Thrombolysis vs Fibrinolysis
What is Thrombolysis?
Thrombolysis is the dissolution of a thrombus (blood clot) due to various chemical and physical agents. It is also known as thrombolytic therapy. It is a specific treatment to dissolve blood clots in blood vessels. It improves blood flow and prevents damages to the tissues and organs. Thrombolysis involves the injection of clot-busting drugs (thrombolytic drugs) through an intravenous line or through a long catheter that delivers drugs directly to the site of a blood clot to dissolve it. Thrombolysis may also involve the usage of a long catheter with a mechanical device attached to the tip of it that removes the blood clot by physically breaking it up.
Figure 01: Thrombolysis
Thrombolysis can be used to treat blood clots in arteries, veins, bypass grafts, and dialysis catheters. Most thrombolytic agents target fibrin in the blood clots, so they are called fibrinolytics. Tissue plasminogen activator (tPA) is a drug that converts plasminogen to plasmin. Plasmin is an endogenous fibrinolytic enzyme that breaks down cross-links in a fibrin mesh. Therefore, recombinant tissue plasminogen activators such as alteplase, reteplase, and tenecteplase can be used as thrombolytic drugs. Other thrombolytic drugs that use the same above mechanism are streptokinase and urokinase. Doctors sometimes may opt-out for another type of thrombolysis technique called mechanical thrombectomy. In this technique, a long catheter tipped with a tiny suction cup, rotating device, and a high-speed fluid jet (or ultrasound device) are used to physically dissolve the blood clot in the blood vessels.
What is Fibrinolysis?
Fibrinolysis is the breakdown of fibrin in the blood clots due to various chemical agents. It can take place in two ways: primary and secondary. Primary fibrinolysis is a normal body process that takes place naturally. However, in secondary fibrinolysis, blood clot dissolves due to a medicinal agent.
Figure 02: Fibrinolysis
In fibrinolysis, fibrin in the blood clot (the product of coagulation) is broken down. The main enzyme that performs this function is plasmin. Tissue plasminogen activator (tPA) and urokinase (upA) convert plasminogen to plasmin. Later, the plasmin enzyme cuts fibrin mesh at various places, leading to the production of circulating fragments called fibrin degradation products (FDPs). FDPs compete with thrombin and slow down the clot formation by preventing the conversion of fibrinogen to fibrin. FDPs are cleared by other proteases or through the kidney and liver. Moreover, streptokinase, anisoylated plasminogen streptokinase activator complex, urokinase, and recombinant human tissue-type plasminogen activator are good examples of drugs that cause fibrin breakdown in the blood clots.
What are the Similarities Between Thrombolysis and Fibrinolysis?
- Thrombolysis and fibrinolysis are two mechanisms that break down blood clots.
- Both mechanisms can use chemical agents to dissolve blood clots.
- Both mechanisms can improve blood flow and prevent damages to the tissues and organs.
- They are used as treatments for cardiovascular diseases.
- Aminocaproic acid and tranexamic acid are used to inhibit both processes.
What is the Difference Between Thrombolysis and Fibrinolysis?
Thrombolysis is the dissolution of thrombus (blood clot) due to various chemical and physical agents, while fibrinolysis is the breakdown of fibrin in the blood clots due to natural processes or various chemical agents. Thus, this is the key difference between thrombolysis and fibrinolysis. Furthermore, the mechanism of thrombolysis involves both fibrin breakdown in the blood clot and mechanical removal of blood clots from blood vessels. On the other hand, the mechanism of fibrinolysis involves only the fibrin breakdown in the blood clot.
The below infographic presents the differences between thrombolysis and fibrinolysis in tabular form for side by side comparison.
Summary – Thrombolysis vs Fibrinolysis
Blood clots can occur due to injured blood vessels or other certain conditions. Thrombolysis and fibrinolysis are two mechanisms that can break down blood clots in the blood vessels. Thrombolysis is the process of dissolution of thrombus (blood clot) due to various chemical and physical agents, while fibrinolysis is the process of breakdown of fibrin in the blood clots due to natural processes or various chemical agents. So, this is the key difference between thrombolysis and fibrinolysis.
Reference:
1. Ansorge, Rick. “Thrombolysis: Definition, Types, Uses, Effects, and More.” WebMD.
2. “Fibrinolysis.” An Overview | ScienceDirect Topics.
Image Courtesy:
1. “Blausen 0024 Angiojet” By “Medical gallery of Blausen Medical 2014”. WikiJournal of Medicine 1 (2). DOI:10.15347/wjm/2014.010. ISSN 2002-4436. – Own work (CC BY 3.0) via Commons Wikimedia
2. “Protein PLAU PDB 1c5w” By Emw – Own work (CC BY-SA 3.0) via Commons Wikimedia