Platelets are small cellular fragments derived from a cell produced by the bone marrow, the megakaryocyte. The megakaryocyte production process by bone marrow and platelet fragmentation lasts about 10 days and is regulated by the hormone thrombopoietin, which is produced by the liver and kidneys.
Platelets play an essential role in the platelet plug formation process, being essential to prevent major bleeding, therefore it is important that the amount of platelets circulating in the body is within the normal reference values.
Main functions
Platelets are essential for the platelet plug formation process during the normal response to vascular injury. In the absence of platelets, several spontaneous leaks of blood can occur in small vessels, which can compromise the person's health status.
Platelet function can be classified into three main stages, which are adhesion, aggregation and release and which are mediated by factors released by platelets during the process, as well as other factors produced by the blood and the body. When there is an injury, platelets are immobilized to the injury site to prevent excess bleeding.
At the injury site, there is a specific interaction between the platelet and the cell wall, adhesion process, and the interaction between platelet and platelet (aggregation process), which are mediated by the fact that Von Willebrand can be found inside the platelets. In addition to the release of the Von Willebrand factor, there is the production and activity of other factors and proteins related to the blood clotting process.
The Von Willebrand factor present in platelets is usually associated with factor VIII of coagulation, which is important for the activation of factor X and continuation of the coagulation cascade, resulting in the production of fibrin, which corresponds to the secondary hemostatic buffer.
Reference values
For the coagulation cascade and the platelet plug formation process to occur correctly, the amount of platelets in the blood must be between 150, 000 and 450, 000 / mm³ of blood. However, there are some situations that can cause the amount of platelets to decrease or increase in the blood.
Thrombocytosis, which corresponds to an increase in the amount of platelets, usually does not generate symptoms, being perceived through the performance of the blood count. The increase in the number of platelets is usually related to changes in the bone marrow, myeloproliferative diseases, hemolytic anemias and after surgical procedures, for example, as there is an attempt by the body to prevent major bleeding. Learn about other causes of platelet growth.
Thrombocytopenia is characterized by a decrease in the amount of platelets that may be due to autoimmune diseases, infectious diseases, nutritional deficiency of iron, folic acid or vitamin B12 and problems related to spleen problems, for example. The decrease in the amount of platelets can be noticed by some symptoms, such as the presence of bleeding in the nose and gums, increased menstrual flow, the presence of purple spots on the skin and the presence of blood in the urine, for example. Learn all about thrombocytopenia.
How to increase platelets
One of the possible alternatives to increase the production of platelets is through the hormonal replacement of thrombopoietin, since this hormone is responsible for stimulating the production of these cellular fragments. However, this hormone is not available for clinical use, however there are drugs that mimic the function of this hormone, being able to increase platelet production about 6 days after the start of treatment, such as Romiplostim and Eltrombopag, which should be used according to medical advice.
The use of medications, however, is only recommended after identifying the cause of the platelet decrease, and it may be necessary to remove the spleen, use of corticosteroids, antibiotics, blood filtration or even platelet transfusion. It is also important to have an adequate and balanced diet, rich in cereals, fruits, vegetables, greens and lean meats to help in the process of blood cell formation and favor the body's recovery.
When platelet donation is indicated
Platelet donation can be made by anyone who weighs more than 50 kg and is in good health and aims to assist in the recovery of the person being treated for leukemia or other types of cancer, people undergoing bone marrow transplantation and cardiac surgery, for example.
The platelet donation can be done without any harm to the donor, since the platelet replacement by the organism lasts about 48 hours, and is made from the collection of whole blood from the donor that immediately goes through a centrifugation process, to there is a separation of blood constituents. During the centrifugation process, the platelets are separated into a special collection bag, while the other blood components return to the donor's bloodstream.
The process lasts around 90 minutes and anticoagulant solution is used throughout the process to prevent clots and preserve blood cells. Platelet donation is only allowed for women who have never been pregnant and for people who have not used aspirin, acetylsalicylic acid or non-hormonal anti-inflammatory drugs in the 3 days before donation.
