Article for the “bio/mol/text” competition: The mechanism for stopping bleeding is essential for the body's survival, but despite decades of research, many details of this system remain unclear. Eight years ago, Mikhail Panteleev told Biomolecule about blood clotting. Since then, a lot of new data has accumulated in this area. In this article we will tell you how a young team of scientists from Moscow State University lifted the veil of secrecy over two mysterious phenomena in the complex system of arterial thrombus formation, showing how dying cells move in it.
Basic functions of platelets
In appearance, platelets are round or oval red plates with a smooth surface. They are formed in the bone marrow. They mature in approximately 8 days. These components constantly circulate in the bloodstream.
The main function of platelets is to ensure blood clotting. In addition, the ability of these blood components to stop bleeding is important. This is ensured by the fact that individual platelets can stick together and stick to sites of vascular damage. The process is automatically started by the human body when there is a risk of bleeding.
An important question is how long platelets live. Their viability time lasts approximately 10 days. Depending on the age of the red plates, their size changes: from 2 to 5 microns in diameter.
The process of platelet renewal in the blood occurs constantly. Therefore, an important factor to ensure the maintenance of blood condition is the balance between the formation of red plates and their death. Otherwise, there may be a tendency to blood clots or increased bleeding.
Anatomy of Human Platelets - Information:
Platelets (Platelet count) are the formed elements of blood involved in ensuring hemostasis. Platelets are small anucleate cells, oval or round in shape; their diameter is 2-4 microns. Platelets are formed in the bone marrow from megakaryocytes. In a calm state (in the bloodstream), platelets have a disc-shaped shape. When activated, platelets acquire a spherical shape and form special projections (pseudopodia). With the help of such outgrowths, blood platelets can connect with each other (aggregate) and adhere to the damaged vascular wall (adhesion ability).
When stimulated, platelets have the property of releasing the contents of their granules, which contain coagulation factors, the enzyme peroxidase, serotonin, calcium ions - Ca2*, adenosine diphosphate (ADP), von Willebrand factor, platelet fibrinogen, platelet growth factor. Platelets can carry some coagulation factors, anticoagulants and other substances on their surface. The properties of platelets interacting with the components of the vessel walls make it possible to form a temporary clot and stop bleeding in small vessels (platelet-vascular hemostasis).
The main function of platelets is to participate in the process of blood clotting (hemostasis) - an important protective reaction of the body that prevents large blood loss when blood vessels are injured. It is characterized by the following processes: adhesion, aggregation, secretion, retraction, spasm of small vessels and viscous metamorphosis, the formation of a white platelet thrombus in microcirculatory vessels with a diameter of up to 100 nm. Another function of platelets is angiotrophic - nutrition of the endothelium of blood vessels. Relatively recently, it has also been established that platelets play a critical role in the healing and regeneration of damaged tissues, releasing growth factors into wound tissue that stimulate the division and growth of damaged cells. Growth factors are polypeptide molecules of various structures and purposes.
The most important growth factors include platelet-derived growth factor (PDGF), transforming growth factor (TGF-β), vascular endothelial growth factor (VEGF), epithelial growth factor (EGF), fibroblast growth factor (FGF), insulin-like growth factor (IGF). Platelet levels naturally fluctuate during the menstrual cycle, rising after ovulation and falling after the onset of menstruation. It also depends on the patient’s diet, decreasing with severe iron deficiency, folic acid deficiency and vitamin B12 deficiency.
Platelets are among the indicators of the acute phase of inflammation; with sepsis, tumors, bleeding, mild iron deficiency, secondary thrombocytosis may occur. It is believed that platelet production in this benign condition is stimulated by IL-3, IL-6 and IL-11. On the contrary, thrombocytosis in chronic myeloproliferative diseases (erythremia, chronic myeloid leukemia, subleukemic myelosis, thrombocythemia) can lead to severe bleeding or thrombosis. The uncontrolled production of platelets in these patients is associated with clonal pathology of the hematopoietic stem cell, affecting all progenitor cells.
A temporary increase in platelet count can be observed after intense physical activity. A slight physiological decrease in platelet levels is observed in women during menstruation. A moderate decrease in platelet count can sometimes be observed in apparently healthy pregnant women. Clinical signs of a decrease in platelet count - thrombocytopenia (increased tendency to intradermal hemorrhage, bleeding gums, menorrhagia, etc.) - usually occur only when the platelet count decreases below 50x103 cells/μl.
A pathological decrease in the number of platelets occurs due to their insufficient formation in a number of diseases of the blood system, as well as with increased consumption or destruction of platelets (autoimmune processes). After massive bleeding followed by intravenous infusions of plasma substitutes, the platelet count may decrease to 20-25% of the original value due to dilution.
An increase in the number of platelets (thrombocytosis) can be reactive, accompanying certain pathological conditions (as a result of the production of immunomodulators that stimulate platelet formation) or primary (due to defects in the hematopoietic system).
Blood test for platelets
A complete blood test can determine the platelet count. The main indications for its implementation are the following:
- Increased bleeding of gums.
- Heavy menstruation.
- The appearance of bruises from minor impacts.
- Frequent nosebleeds.
- Difficulty stopping bleeding from minor injuries.
The number of platelets in the blood is measured in thousands per 1 microliter of blood. Counting is carried out in specialized laboratories in various ways that guarantee high accuracy.
The normal platelet count in the blood depends on gender and age and is:
- For men, 200–400 thousand.
- In women, 180–320 thousand, during menstruation the amount can decrease to 75–220 thousand, and during pregnancy to 100–310 thousand.
- In children, indicators depend on age, and the corresponding values are given in special tables.
To conduct a general blood test, blood is taken from a finger. No special preliminary preparation is required before this. To ensure accurate results, it is better to donate blood in the morning on an empty stomach. At the same time, 12 hours before the procedure it is not recommended to consume fatty spicy foods, carbonated drinks, and alcohol.
Additionally, to determine blood clotting indicators, Sukharev and Lee-White tests are performed. They are informative and allow you to obtain the necessary additional data about the pathological condition. This will allow you to carry out correct treatment measures and avoid dangerous consequences.
What do elevated platelets mean?
An increase in the concentration of Bizzocero plaques can warn of the presence of various pathological processes in the body - the development of tuberculosis infection, blood cancer (leukemia), cancer of various organs, Hodgkin's lymphoma.
- Platelet counting according to Fonio - is the method accurate?
Thrombocytosis (increased platelets) is a constant companion:
- erythrocytosis;
- inflammatory intestinal and joint pathologies;
- chronic form of myeloid leukemia;
- acute course of infectious diseases;
- intravascular hemolysis and anemia.
An increase in the number of platelets is caused by severe stress, general intoxication of the body and blood loss, which can ultimately lead to the development of thrombocytemia and failure of the functions of stem cells in the bone marrow.
Oddly enough, significant blood loss does not reduce the concentration of platelet platelets, but, on the contrary, increases it. This is due to the presence of compensated properties of the body that can replenish platelet losses.
It doesn’t matter for what reasons platelets go beyond the normative values. In such a situation, a medical assessment with appropriate therapy is necessary.
Increased platelet levels
Elevated platelets are a pathological condition. It is called thrombocytosis. The main danger of the pathology is the increased risk of blood clots.
The cause of an increase in the level of platelets in the blood can be various diseases. Most often thrombocytosis occurs against the background of:
- Malignant neoplasms.
- Infectious diseases.
- Helminthic infestations.
- Surgical operations.
- Autoimmune pathologies.
- Kidney failure.
High levels of platelets in the blood are observed in older people. Temporarily, indicators may increase after heavy physical exertion, for example, after playing sports.
The symptoms of thrombocytosis are characteristic, but mild. It is imperative to conduct a general blood test if the following symptoms are noted:
- Pain in the fingers and toes.
- Itching of skin surfaces.
- Unreasonable weakness, which leads to decreased performance.
- Lack of appetite.
Competition "bio/mol/text"-2019
This work was published in the “Own Work” category of the “bio/mol/text” competition 2019.
The general sponsor of the competition and partner of the Skoltech nomination is the Skoltech Center for Life Sciences.
The nomination partner is the Russian Science Foundation.
Competition sponsor: the largest supplier of equipment, reagents and consumables for biological research and production.
The audience award was sponsored by BioVitrum.
"Book" sponsor of the competition - "Alpina Non-Fiction"
Specialists and non-specialists are well aware of the ominous word “thrombosis”. The word “thrombus” is traditionally perceived as something dangerous. However, not all blood clots are dangerous. If the vascular wall is damaged, the body must quickly form something like a plug that will prevent blood from flowing out of the artery or vein. Thus, the formation of plugs, or, in scientific terms, hemostatic blood clots , is a key task that is solved by the human hemostasis system (and, of course, not only humans). However, sometimes this system fails, and damage to the vessel leads to the formation of a massive intravascular thrombus, which almost completely blocks blood flow. If this process occurs in a large artery that supplies blood to a vital organ, such a blood clot can cause serious complications and even death. Myocardial infarction and ischemic stroke are perhaps the most well-known and common complications caused by arterial thrombosis, which are today the most common cause of death and disability in people in developed countries [1].
Why in some cases, in response to damage, the hemostasis system works excessively and forms a deadly plug in the vessel? Despite many decades of research, this question remains unanswered. The lack of understanding of the mechanisms that regulate the formation of a blood clot leads to the fact that today there is no reliable way to prevent thrombosis: taking existing antithrombotic drugs is associated with a fairly high risk of bleeding, including life-threatening ones.
Decreased platelet levels
Low platelet levels, the norm of which differs between men and women, provoke the development of a condition known as thrombocytopenia. Very often it occurs against the background of uncontrolled use of medications: antidepressants and antibiotics.
The reasons for a decrease in the level of platelets in the blood can be various infectious diseases: ARVI, hepatitis, herpes, etc. Thrombocytopenia can be observed when a large number of blood thinning products are included in the diet. These are ginger, cherries, garlic, onions, etc.
Non-infectious factors that reduce the level of platelets in the blood include pregnancy, vitamin deficiency, alcohol or heavy metal poisoning.
Thrombocytopenia can be suspected based on the following signs:
- Heavy menstruation.
- Frequent nosebleeds.
- The appearance of hematomas.
With a constant pathological decrease in the level of platelets in the blood, the risks of developing severe bleeding and stroke conditions, which are life-threatening, increase.
Restoring platelet levels in the blood
You can normalize the level of platelets in the blood with a balanced diet. It is important to saturate your diet with foods high in materials and microelements. You need to give up spicy food, alcohol, fast food and sweet carbonated drinks, lead a healthy lifestyle and maintain a drinking regime.
If it is not possible to normalize the indicators using natural methods, then you need to undergo a full examination by a hematologist. If platelet levels are elevated, special medications may be prescribed - anticoagulants or antiplatelet agents. They thin the blood and minimize the risk of blood clots. But at the same time, they should be taken only as prescribed by a doctor. It should be understood that stabilization of the condition is possible only after eliminating the underlying causes that provoke deviations from the norm.
