How clotting plugs holes in your blood vessels

Ninh Khuong
14 July 2015

Above: Image © istockphoto.com/ThamKC

If you accidentally nicked a pipe and it burst, you would probably try to plug the hole as quickly as possible to stop the flow of water. Something very similar happens when you cut yourself. Blood vessels are the pipes that bring blood to different parts of your body. When damaged, they begin to leak blood. Your body immediately tries to stop the leak and repair the damage using a process called blood clotting. The process starts with a formation of a blood clot and ends when the wound is healed and the clot is dissolved inside the body.

Do you know? Vitamin K is essential for blood clotting. It is used to treat of blood clotting problems in newborns, to help heal wounds, and to reduce scars and bruises.When blood doesn’t clot as it should, uncontrolled bleeding can be life threatening. Overly large blood clots can also cause serious health problems. Along with explaining how blog clotting works, this article will discuss blood clotting disorders like hemophilia, as well as ongoing research into potential treatments.

How blood clotting works

There are two steps involved in forming a blood clot. First, specialized blood cells called platelets gather at the site of the damage, clump together, and form a clot to stop the bleeding. The next step occurs almost simultaneously, when molecules called clotting factors spring into action. They help control bleeding by creating a complex network of fibrin (long fibrous protein strains) that strengthens the clot and restricts blood flow. As a result, bleeding begins to slow down and eventually stops. Over time, the clot is removed via a process called fibrinolysis. Plasmin, the enzyme involved in fibrinolysis, breaks down the fibrin network into small parts that dissolve in the bloodstream.

Blood clotting also plays an important role in the immune system. When a blood clot is formed, it acts as a trap for bacteria and microorganisms. And when a pathogen such as a food-poisoning bacteria enters the bloodstream, a special type of white blood cell is quickly sent to the site of the wound. These cells, called neutrophils, are equipped to recognize and destroy invading pathogens. Neutrophils also create huge numbers of small blood clots that trap pathogens and prevent them from entering further into your body. In this way, clotting plays a dual role in your body by stopping the bleeding and fighting infection.

Clotting disorders and potential treatments

Hemophilia is a rare genetic disorder caused by a lack of clotting factors. It prevents blood clots from forming normally and primarily affects men. About 1 out of every 5000 male newborns have the condition. Hemophilia is also called “the royal disease” because it has affected a large number Queen Victoria’s descendants, who are spread across several European royal families.

Hemophilia is particularly dangerous when bleeding occurs inside the body. For example, when someone with hemophilia falls and injures their knee, bleeding can occur at the joint where the two bones meet. Without normal blood clotting, the bleeding will continue and causing swelling, pain, and inflammation.

After a few days, the person’s body will secrete plasmin. But since there is no blood clot to break down, the enzyme weakens the surrounding bone cartilage, which is flexible connective tissue that provides structure and support. This can cause severe damage to the bones and a lot of pain when the person tries to move their leg.

Currently, the only effective treatment for hemophilia involves injecting patients with the clotting factors that their own bodies cannot produce. These drugs are very expensive, costing between $40,000 and over $200,000 a year.

Other blood clotting disorders involve damage caused to blood vessels by clots that are too large. For example, an inherited disease called factor V Leiden causes blood to be thicker than normal, which leads to blood clots that form too easily. Hormone birth control pills can also sometimes cause dangerous blood clots.

Do you know? Blood clots are the leading cause of women’s deaths in childbirth. Blood clots form more easily during labour and childbirth to prevent blood loss, but clots can also travel to the lungs and prevent breathing.A large blood clot can obstruct the flow of blood to tissues, causing to oxygen deprivation and tissue damage. Severe blockage due to blood clots occur in people with atherosclerosis, a disease in which fatty substances build up inside the walls of arteries. This can lead to stroke, a sudden stop in brain function that happens when the supply of oxygen-rich blood to the brain is temporarily cut off. Strokes can result in uncontrolled bleeding and permanent brain damage if the oxygen supply to the brain is not restored fast enough.

Recently, researchers have discovered that spirulan, a polysaccharide found in blue-green algae, can prevent the formation of blood clots. In a similar way to plasmin. spirulan causes blood clots to break down. Researchers hope to use this product of algae to develop treatments for clotting disorders where oversized clots restrict the flow of blood.

* * *

Blood clotting is an extremely important physiological process that helps heal wounds, control bleeding, and fight against invasive pathogens. Understanding how blood clotting works can help scientists develop treatments against inherited blood clotting disorders such as hemophilia and factor V Leiden.

Learn more!

Spirulan from Blue-Green Algae Inhibits Fibrin and Blood Clots: Its Potent Antithrombotic Effects (2015)
J. H. Choi, S. Kim, & S.-J. Kim, Journal of biochemical and molecular toxicology 29
Link to abstract. Registration or subscription required to view full text.

Interaction of pathogenic vibrio bacteria with the blood clot of the Pacific white shrimp, Litopenaeus vannamei (2014)
V. Chaikeeratisak, A. Tassanakajon, & P. B. Armstrong, The Biological Bulletin 226

Scientific articles on research into blood clots and treatments for clotting disorders.

About Bleeding Disorders (2012)
World Federation of Hemophelia

What Is Deep Vein Thrombosis? (2011)
US National Heart, Lung, and Blood Institute

About clots
US National Blood Clot Alliance

Websites with general information on blood clotting disorders.

Ninh Khuong

Ninh is completing her third year of undergrad in Biochemistry at Mount Allison University, NB. She was a Let's Talk Science volunteer for two years before she became an outreach coordinator. She also writes for The Argosy, 7Mondays, and The CHMA. Aside from writing and volunteering for Let's Talk Science, she enjoys swimming, running, writing poetry, painting, cooking, traveling, and playing the piano.


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