Every year on June 14, World Blood Donor Day is celebrated around the world. The Mail.ru Health project asked Ksenia Kaluzhskaya, a hematologist at the Fomin Clinic, to analyze the five most interesting facts about blood donation.
1. Scientists have long been trying to create the perfect artificial blood. But it’s not as easy as it seemed at first
Initially, blood substitutes were used to replace blood and plasma during blood loss by restoring the volume of circulating blood. These were, for example, Ringer’s solution, polyglucin, gelatinol, lactosol, blood plasma, etc. However, they only maintain the volume of blood flow, but do not perform the respiratory function of the blood.
Therefore, at various stages of scientific discoveries, scientists have tried to create the ideal “artificial blood”, thanks to which blood donation will cease to be so relevant. But this process turned out to be not so simple (and also very expensive).
Modern science has turned its attention to blood substitutes with the function of transporting oxygen to cells during large blood losses, extensive operations, etc.
Currently, there are two main directions in the development of artificial oxygen carriers:
Creation of drugs based on synthetic materials (for example, emulsions of fully fluorinated organic compounds) capable of reversibly binding and transferring oxygen molecules. The most famous of them is the domestic drug “Perftoran”, which has long been used as an antishock and anti-ischemic agent.
A large number of studies have shown the positive effect of perftoran on the erythrocyte membrane, however, despite the proven high effectiveness of the drug, it remains expensive.
The second direction is the development of various types of natural or modified hemoglobin.
At first, attempts were made to create individual hemoglobin molecules, but they instantly bound to plasma proteins, such as albumin, which led to the formation of haptoglobin and the development of adverse reactions, such as arterial hypertension and acute kidney damage.
Therefore, various methods have been proposed to “protect” hemoglobin and place it in a capsule. Artificial red blood cells, hemosomes, liposome-encapsulated hemoglobin (LEH), etc. appeared, but many of them had drawbacks.
Microcapsules containing hemoglobin showed their ineffectiveness in animal experiments: the body’s immune system recognized the capsules and destroyed them. In addition, an artificial red blood cell can only be made spherical, and therefore less elastic. It got stuck in the lumen of the capillary, which led to its blockage.
Compared to liposomes, polymer nanocapsules were stronger and had a more porous structure, and their synthesis required less material. However, liposomes are selectively permeable only to water and nonpolar molecules such as oxygen. Serious disadvantages of simple hemosomes were their short period of circulation, equal to 12–18 hours, and their gluing, leading to a deterioration in their properties during storage.
Despite significant progress, the main problem in developing a blood substitute is not even the membrane itself, but rather the internal contents.
The problem is caused by the difficulty of maintaining hemoglobin molecules in a stable state for a long time, since the iron of hemoglobin is constantly oxidized, turning from a divalent to a trivalent form (methemoglobin), which is not involved in oxygen transport.
Receiving and storing donor blood is many times cheaper than obtaining even the simplest encapsulated hemoglobin preparation. Although experiments are ongoing, it must be admitted that a solution to the problem of global blood shortage has not yet been found.
2. Blood donors live longer and get sick less.
According to statistics, donors are less likely to suffer from cardiovascular diseases and, on average, live five years longer than those who do not donate blood regularly. This is largely due to the fact that regular donors are healthier people because they prefer to monitor the condition of their bodies in order to continue to benefit humanity.
A healthy diet, regular exercise, good sleep, giving up bad habits (smoking, excessive alcohol consumption) are a necessary condition for the donor’s well-being during and after donating blood.
Donating blood is not only honorable and noble, but also an excellent way to stay healthy. It’s not for nothing that there is an expression: “as healthy as a donor!”, since the donor will systematically track his condition – and for free!
Before donation, a medical examination is always carried out by a transfusiologist, a study of the composition and biochemical parameters of peripheral blood, and samples of the donor’s blood are taken for testing for blood-borne infections. The test results are brought to the attention of the donor, and if deviations in the tests are detected, the donor receives the necessary recommendations.
Donation does not harm the human body and is safe, because the stations use only sterile equipment and take care of everyone’s health.
In terms of health benefits, moderate blood loss stimulates the bone marrow and immunity: the donor donates a physiological volume of blood and its components, which is not significant blood loss, since the bone marrow quickly compensates for this volume.
But you should always remember that the standard dose for donation is 450 ml of blood (about 10% of the total blood volume), which is approximately 200–250 mg of iron.
Therefore, it is important to donate blood again no earlier than after 60 days to replenish iron reserves and restore the body’s strength.
3. Is it possible to become a blood donor after death?
Blood is the tissue of the internal environment of our body, which flows through the vessels and consists of liquid intercellular substance (plasma) and formed elements – cells (erythrocytes, leukocytes and platelets). And theoretically, like any organ and tissue, it can be transplanted to another person after death. Likewise, you can become a blood donor after death.
This practice was actively carried out in the USSR in the 1920s–1960s, when religious and ethical aspects were relegated to the background. It was believed that cadaveric blood was stored longer and, of course, there was no talk of any physiological subsidies: several times more blood could be obtained from a dead donor
than from a living one, which, naturally, was a great advantage.
In the period from 1932 to 1944. at the Research Institute of Emergency Medicine named after. N.V. Sklifosovsky conducted 5,000 cadaveric blood transfusions, even a special technique was developed for collecting cadaver blood (the so-called blood a few hours after the death of a person, when the blood is no longer able to coagulate, becoming fibrinolyzed).
At that time, this method was considered very promising, but now it is not used for many reasons.
Firstly, there is a high risk of infectious complications and thrombotic reactions , since a large amount of fibrinolysis products is present in the blood.
Secondly, according to the legislation of the Russian Federation in Federal Law No. 323 “On the fundamentals of protecting the health of citizens in the Russian Federation”, the removal of organs and tissues from the body of a deceased can only be carried out if certain conditions are met:
- if a council of doctors has declared a person’s brain death;
- if the deceased citizen was of age and capable;
- if he expressed consent to the removal of organs from his body after death;
- if one of the parents agreed to the removal of organs from the body of a minor or incompetent citizen after his death.
Thirdly, in the modern world, religious and ethical aspects have great weight, which is also an obstacle to such practice.
4. It is possible to mix blood from people of different races during transfusion. But there are nuances
In 1901, the Austrian physician Karl Landsteiner discovered 4 blood groups (for which he was awarded the Nobel Prize). The scientist noticed that sometimes the serum of one person sticks together the red blood cells of another, and came to the conclusion that people’s blood is divided into different groups, and, accordingly, safe transfusions are possible only between a donor and a recipient with compatible types.
Subsequently, blood transfusions began to be carried out according to the ABO system and the Rh factor in order to avoid agglutination (sticking together of red blood cells) and associated complications.
As a rule, no differences in the composition of blood components are detected in people of different races, and in principle, the donor and recipient may have different skin colors, but there are interesting differences in the characteristics of the antigenic composition of red blood cells.
Scientists have discovered other blood group proteins; currently there are more than 30 of them, but they are less common than the ABO and Rh factor blood group proteins.
For example, these include the Kell factor; it occurs in 10% of the Russian population, so now it is also determined before transfusion.
An interesting feature of the Duffy system proteins is that they are found in almost the entire population of Africa, since this mutation makes them immune to the development of tertian malaria.
Other systems, such as the Bombay system (found among residents of the Indian state of Maharatsha), Diego blood group (found among Native Americans and representatives of the Mongoloid race), Lewis system, Kidd factor and other several dozen blood groups are rare and are not primarily determined .
Therefore, differences in antigenic composition affect the possibility of selecting a donor; In this regard, in the modern world the phenotype (set of red blood cell antigens) of the donor and recipient is determined, and if they match, blood can be transfused.
5. You cannot become a donor if you have infectious and chronic diseases. But after piercing, tattoo or tooth extraction – you can, but not right away
Almost any healthy person can become a donor if he is over 18 years of age (the restriction is related to the legislation of the Russian Federation on human capacity), has no contraindications to donation and weighs more than 50 kg.
There are permanent and temporary restrictions on blood donation. Their full list can be found on the Blood Service website .
Constant contraindications include the presence of infectious (HIV, syphilis, viral hepatitis, tuberculosis, etc.) and parasitic diseases, cancer, blood diseases, as well as a number of other conditions. These reasons underlie the safety of donated blood components for patients so that the disease is not transmitted to them along with the blood.
Secondly, restrictions associated with other concomitant or chronic diseases in the donor are important for his own safety. For example, blood cannot be donated if you have diseases of the heart, respiratory system, kidneys or gastrointestinal tract. Or, from unobvious contraindications, for example, with some visual impairments: with high myopia, after blood donation, blood circulation in the retina may decrease, which will aggravate the situation.
Temporary bans have different periods: for example, if you weigh less than 50 kg, you can become a donor only after gaining weight. A period of 120 calendar days is required from the moment of completion of procedures, such as medical and cosmetic procedures involving violation of the skin (tattoos, piercings, acupuncture, etc.), or after surgical intervention, including artificial termination of pregnancy or tooth extraction.
The ban on donating blood also applies to pregnant women: it remains in place for 365 days after childbirth and 90 days after the end of breastfeeding.
For non-pregnant women, there are recommendations to refrain from donating during menstruation (due to existing blood loss).
If the donor has an acute or chronic inflammatory disease in the acute stage, regardless of location, then the medical withdrawal from donation is 30 calendar days after the acute period has stopped. The same applies to common ARVI and influenza.
The exception is exacerbation of stomach and (or) duodenal ulcers, as well as kidney diseases not listed in the list of permanent contraindications: in these conditions, blood donation is possible 1 year from the moment the acute period is relieved.
If a person has recently been vaccinated, the medical exemption from blood donation is valid from 10 days to 1 year, depending on the vaccination.
In addition, you cannot donate blood while taking certain medications – they are also listed on the website.
