Fibrin is a strong protein that is an important element in the last stage of coagulation, the clotting of blood to stop bleeding. It is insoluble and creates a connective barrier at the site of a wound, which then hardens to stop bleeding. It is not made in the body until it is needed. When a person is injured, a signal is sent out that initiates the production of fibrin. The inability to create the protein or a deficiency in the protein can result in life threatening conditions.
This protein is created though a process called polymerization, which is when small molecules called monomers join together. When someone sustains a wound, the body releases a clotting enzyme called thrombin, which then signals the body to make a soluble protein called fibrinogen. These two substances then join at the site of the wound to create fibrin, which will form the clot. In addition to coagulation, fibrin also plays a role in related activities, such as activating platelets, signal transduction, and protein polymerization.
Without fibrin to complete the clotting process, individuals can suffer from hemorrhage or hemophilia. Hemophilia includes clotting disorders that prevent or inhibit blood clotting. A hemorrhage occurs when an individual loses more than a quarter of the blood in his circulation. It is also dangerous to have too much fibrin because it can cause thrombosis, a clot within a blood vessel. Both hemophilia and thrombosis when left untreated can lead to death.
Dysfibrinogenemia is a liver problem that is associated with either a decrease in fibrin production or abnormal production of the protein, both of which are dangerous. Individuals with this disorder are prone to hemorrhages. They are often treated with therapies that replace the missing enzymes needed to produce the protein molecules. Other treatments include plasma transfusions or medications that aide in coagulation.
There are also hereditary disorders that cause fibrin abnormalities. These include hypofibrinogenemia, dysfibrinogenemia, and hypodysfibrinogenemia. These disorders result in disruption in the protein's creation, which can lead to bleeding disorders.
Certain products are made that act like the protein as well. Fibrin glue, for example, is an artificial substance created from thrombin and fibrinogen. It is fast acting and works as a skin adhesive. This glue is used most often in surgeries to decrease healing time and to seal or cover holes and sutures.
The body also produces fibrin scaffolds which are produced by the body naturally after injuries as well. Physicians can manipulate these scaffolds to rebuild tissue. They are especially useful for repairing damage to the nervous and cardiovascular systems.