Donated and artificial blood By Steph Chenney
Blood • Blood is essential to life, and contains many of the substances that are vital for survival. Blood is mainly made up of red blood cells (≈45%), plasma (≈ 54%), white blood cells and platelets (≈ 1%). Blood makes up about 7% of our body weight, and in a healthy adult there is around five litres of blood. • In Australia, donated blood is collected by the Australian Red Cross Blood Service, and is used everyday in medical facilities. • When blood is donated, many products are extracted, and each have different uses: • Red Blood Cells • Plasma • White Blood Cells • Platelets • Cryoprecipitate • Factor VIII and Monofix • Donated blood is placed in a centrifuge, where it is spun at high speeds to separate the blood into layers. The plasma rises to the top, the “buffy coat”, made up of white blood cells and platelets rests in the middle, and the red blood cells sink to the bottom.
Red Blood Cells • Red blood cells (erythrocytes) make up about 40-45% of the total blood volume, and carry the pigment haemoglobin, which gives blood its red colour. Haemoglobin carries oxygen molecules through the blood, from the heart to the body’s cells. Healthy red blood cells are 6-8µm, and do not contain nuclei. This allows them to bend and fit through narrow blood capillaries. • Red blood cells are used to treat: • People with severe anaemia (lack of iron) • Those whose red blood cells are not functioning • correctly, for example during leukaemia • Patients that have lost a lot of blood, • for example in an accident or during surgery
Plasma • Plasma is the yellow tinted fluid in which the red blood cells, platelets and white blood cells are suspended. About 55% of our blood is plasma, which is made up of water, sugar, fat, proteins and salts. Plasma is very versatile, and seventeen different products can be created from donated plasma. • Plasma is used to: • Treat patients with severe burns • Help create immunisations • Treat people with haemophilia or • von Willebrand disease • Support the healing of wounds after surgery • Boost blood volume and therefore blood pressure • Treat Alpha 1-antitrypsin deficiency – • a genetic disease that cause liver and lung failure Sophie Delezio
White Blood Cells • White blood cells, or leukocytes, defend the body against infection and disease. In a single drop of blood, there can be between 7000 and 25,000 white blood cells, and even more if the body is fighting off an illness. In leukaemia patients, the level of white blood cells is higher, reaching up to 50,000 in a drop of blood. • White blood cells are used: • To treat patients suffering a severe • infection, to speed up recovery • To boost the immune system of • patients who are more vulnerable • to diseases for example the elderly • To treat patients with immune deficiency • disorders White blood cell (leukocyte)
Platelets • Platelets (thrombocytes) are extremely small cell fragments that lack a nucleus and have irregular shapes. The outer membrane of the platelet is composed of a very sticky protein, so the thrombocyte can adhere to others to clot blood when an injury occurs. It is vital for regular blood donations to occur, because platelets only have a shelf life of five days. • Platelets are used: • In cancer patients, as the disease or treatment can • greatly reduce their platelet count. If this count gets • too low bleeding can occur, which can be extremely • dangerous, especially if it happens in the brain • To treat people with thrombocytopenia, or low • platelet count • To help clot major wounds and prevent bleeding in emergency patients, for example people in a car accident thrombocyte
Cryoprecipitate, factor VIII and Monofix • Cryoprecipitate is derived from plasma, and contains blood clotting factors. It is used to treat: • Haemophilia • von Willebrand disease • Severe bleeding Factor VIII and Monofix are also extracted from plasma, and are used to treat haemophilia, allowing sufferers to lead relatively normal lives
Artificial Blood As donated blood does not have a very long shelf life (up to 42 days), a blood substitute, or artificial blood, is needed. There are two main points of research into artificial blood; haemoglobin-based oxygen carriers and perfluorocarbon-based substitutes. Haemoglobin-Based Oxygen Carriers (HBOC’s) Haemoglobin is derived from animal blood, and undergoes treatment to purify it. This rids the haemoglobin of any diseases and prevents an auto-immune response from occurring in a patient. The HBOC’s can be stored for years, and have good potential for carrying oxygen effectively through the bloodstream and releasing it into tissues. HBOC’s have not yet been approved for medical use Perfluorocarbon-Based Substitutes Perfluorocarbons are molecules that contain fluorine and carbon, and can carry up to five times more oxygen than human blood can. Perfluorocarbons can be stored indefinitely, and can be treated to be entirely disease free and sterile. Perfluorocarbon-Based Substitutes have not yet been cleared for medical use.
The need for artificial blood Artificial blood is an important research point, as blood is used everyday in medical facilities, and the amount of donations cannot meet this demand. Currently, 1 in 3 Australian’s need blood, but only 1 in 30 donates.¹ This statistic shows how necessary donated blood is, but unfortunately there is a lack of donors. This means we need a substitute to ensure a constant supply of blood to use in medicine. Artificial blood allows this to happen. Fresh blood has a short shelf life, and many countries lack the storage facilities required. Artificial blood can be stored for years on end, at room temperature. This allows underdeveloped countries to have access to a blood supply. Donated blood can spread diseases such as HIV and hepatitis to the receivers, endangering lives and raising the number of infected people. Artificial blood can be treated and sterilised, meaning there is no risk of diseases being transferred. Artificial blood is needed as donated blood has many issues, issues that blood substitutes can solve. ¹ Australian Red Cross Blood Service
Bibliography • Websites • American Society of Haematology, Blood Basics, http://www.hematology.org/patients/blood-basics/5222.aspx, 21st September 2011, Accessed 19th November, 2012 • Australian Red Cross Blood Service, Blood Components, http://www.donateblood.com.au/about-blood/components, 17th June 2011, Accessed 19th November, 2012 • Australian Red Cross Blood Service, Plasma Products, http://www.donateblood.com.au/about-blood/plasma-products, 17th June 2011, Accessed 21st November, 2012 • Bianco, C. How Blood Works, http://science.howstuffworks.com/environmental/life/human-biology/blood.htm, 1st April 2001, Accessed 21st November, 2012 • O’Neil, D. Blood Components, http://anthro.palomar.edu/blood/blood_components.htm, 15th March 2003, Accessed 19th November, 2012 • Wilson, T. How Artificial Blood Works, http://science.howstuffworks.com/innovation/everyday-innovations/artificial-blood.htm, 29th December 2006, Accessed 21st November, 2012
Bibliography • Books • Hatherly, J. & Kelly, N. Biology, For Units 3 And 4, 1992, McGraw-Hill Book Company • Mudie, K. & Brotherton, J. Core Biology, 1985, Heinemann Educational Australia • Mudie, K. & Brotherton, J. Heinemann Biology, Second Edition, 2004, Heinemann Publishing • Snyder, W., Kennedy, E. & Aubusson, P. Biology, The Spectrum Of Life, 1990, Oxford University Press • Song: Feel So Close by Calvin Harris