Problems of modern transplantology. Current problems of transplantation
The problem of organ shortage for transplantation is urgent for all humanity as a whole. About 18 people die every day due to the lack of organ and soft tissue donors without waiting their turn. Organ transplants in the modern world are mostly performed from deceased people who, during their lifetime, signed the appropriate documents indicating their consent to donation after death.
What is transplantation
Organ transplantation involves removing organs or soft tissue from a donor and transferring them to a recipient. The main direction of transplantology is organ transplantation - that is, those organs without which existence is impossible. These organs include the heart, kidneys, and lungs. While other organs, such as the pancreas, can be replaced by replacement therapy. Today, organ transplantation offers great hope for prolonging human life. Transplantation is already being successfully practiced. These are the kidneys, liver, thyroid gland, cornea, spleen, lungs, blood vessels, skin, cartilage and bones to create a framework so that new tissues can form in the future. For the first time, a kidney transplant operation to eliminate acute renal failure The patient was performed in 1954, the donor was an identical twin. Organ transplantation in Russia was first performed by Academician B. V. Petrovsky in 1965.
What types of transplantation are there?
There are a huge number of terminally ill people in need of transplants around the world. internal organs and soft tissues, since traditional methods of treating the liver, kidneys, lungs, and heart provide only temporary relief, but do not fundamentally change the patient’s condition. There are four types of organ transplantation. The first of these - allotransplantation - occurs when the donor and recipient belong to the same species, and the second type includes xenotransplantation - both subjects belong to different species. In the case when tissue or organ transplantation is performed in or animals raised as a result of consanguineous crossing, the operation is called isotransplantation. In the first two cases, the recipient may experience tissue rejection, which is caused by the body's immune defense against foreign cells. And in related individuals, tissues usually take root better. The fourth type includes autotransplantation - transplantation of tissues and organs within one organism.
Indications
As practice shows, the success of the operations performed is largely due to timely diagnosis and accurate determination of the presence of contraindications, as well as the timeliness of organ transplantation. Transplantation must be predicted taking into account the patient's condition both before and after surgery. The main indication for surgery is the presence of incurable defects, diseases and pathologies that cannot be treated with therapeutic and surgical methods, as well as those threatening the patient’s life. When performing transplantation in children, the most important aspect is determining the optimal moment for the operation. As experts from such an institution as the Institute of Transplantology testify, postponing the operation should not be carried out for an unreasonably long period, since the delay in the development of a young organism can become irreversible. Transplantation is indicated in case of a positive life prognosis after surgery, depending on the form of the pathology.
Organ and tissue transplantation
In transplantology greatest distribution received autotransplantation, as it eliminates tissue incompatibility and rejection. Most often, operations are performed on fatty and muscle tissue, cartilage, bone fragments, nerves, and pericardium. Vein and vascular transplantation is widespread. This became possible thanks to the development of modern microsurgery and equipment for these purposes. A great achievement in transplantology is the transplantation of fingers from the foot to the hand. Autotransplantation also includes transfusion of one's own blood in case of large blood losses during surgical interventions. During allotransplantation, bone marrow and blood vessels are most often transplanted. This group includes blood transfusions from relatives. It is much rare to carry out operations on this because so far this operation faces great difficulties, however, in animals, transplantation of individual segments is successfully practiced. A pancreas transplant can stop the development of this serious illness like diabetes. IN last years 7-8 out of 10 operations performed are successful. In this case, not the entire organ is transplanted, but only part of it - the islet cells that produce insulin.
Law on organ transplantation in the Russian Federation
On the territory of our country, the transplantology industry is regulated by the Law of the Russian Federation of December 22, 1992 “On Transplantation of Human Organs and (or) Tissues.” In Russia, kidney transplantation is most often performed, and less often heart and liver transplantation. The law on organ transplantation considers this aspect as a way to preserve the life and health of a citizen. At the same time, the legislation considers the preservation of the life of the donor to be a priority in relation to the health of the recipient. According to the Federal Law on organ transplantation, objects can be the heart, lung, kidney, liver and other internal organs and tissues. Organ removal can be carried out both from a living person and from a deceased person. Organ transplantation is carried out only with the written consent of the recipient. Donors can only be legally capable persons who have passed medical examination. Organ transplantation in Russia is carried out free of charge, since the sale of organs is prohibited by law.
Donors for transplantation
According to the Institute of Transplantology, every person can become a donor for organ transplantation. For persons under eighteen years of age, parental consent is required for the operation. When you sign a consent to donate organs after death, a diagnosis and medical examination is carried out to determine which organs can be transplanted. Carriers of HIV, diabetes mellitus, cancer, kidney disease, heart disease and other serious pathologies are excluded from the list of donors for organ and tissue transplantation. Related transplantation is carried out, as a rule, for paired organs - kidneys, lungs, as well as unpaired organs - liver, intestines, pancreas.
Contraindications for transplantation
Organ transplantation has a number of contraindications due to the presence of diseases that can worsen as a result of the operation and pose a threat to the patient’s life, including death. All contraindications are divided into two groups: absolute and relative. The absolute ones include:
- infectious diseases in other organs on a par with those that are planned to be replaced, including the presence of tuberculosis and AIDS;
- dysfunction of vital important organs, damage to the central nervous system;
- cancerous tumors;
- the presence of developmental defects and birth defects, incompatible with life.
However, during the period of preparation for surgery, thanks to treatment and elimination of symptoms, many absolute contraindications become relative.
Kidney transplant
Kidney transplantation is of particular importance in medicine. Since this is a paired organ, when it is removed, the donor does not experience disruptions in the functioning of the body that threaten his life. Due to the peculiarities of the blood supply, the transplanted kidney takes root well in the recipients. The first experiments on kidney transplantation were carried out in animals in 1902 by researcher E. Ullman. During transplantation, the recipient, even in the absence of supportive procedures to prevent rejection of the foreign organ, lived for just over six months. Initially, the kidney was transplanted onto the thigh, but later, with the development of surgery, operations began to transplant it into the pelvic area, a technique that is still practiced today. The first kidney transplant was performed in 1954 between identical twins. Then in 1959, an experiment was carried out on kidney transplantation of fraternal twins, which used a technique to counteract graft rejection, and it proved its effectiveness in practice. New agents have been identified that can block the body's natural mechanisms, including the discovery of azathioprine, which suppresses the body's immune defense. Since then, immunosuppressants have been widely used in transplantology.
Organ preservation
Any vital organ that is intended for transplantation is subject to irreversible changes without blood supply and oxygen, after which it is considered unsuitable for transplantation. For all organs, this period is calculated differently - for the heart, time is measured in a matter of minutes, for the kidney - several hours. Therefore, the main task of transplantology is to preserve organs and maintain their functionality until transplantation into another organism. To solve this problem, canning is used, which consists of supplying the organ with oxygen and cooling. The kidney can be preserved in this way for several days. Preservation of an organ allows you to increase the time for its examination and selection of recipients.
Each of the organs, after receiving it, must be preserved; for this, it is placed in a container with sterile ice, after which it is preserved with a special solution at a temperature of plus 40 degrees Celsius. Most often, a solution called Custodiol is used for these purposes. Perfusion is considered complete if a clean preservative solution without blood admixtures emerges from the mouths of the graft veins. After this, the organ is placed in a preservative solution, where it is left until the operation.
Graft rejection
When a transplant is transplanted into the recipient's body, it becomes the object of the body's immunological response. As a result of the protective reaction of the recipient's immune system, a number of processes occur at the cellular level, which lead to rejection of the transplanted organ. These processes are explained by the production of donor-specific antibodies, as well as antigens of the recipient's immune system. There are two types of rejection - humoral and hyperacute. In acute forms, both rejection mechanisms develop.
Rehabilitation and immunosuppressive treatment
To prevent this side effect, immunosuppressive treatment is prescribed depending on the type of surgery performed, blood type, donor-recipient compatibility, and the patient's condition. The least rejection is observed with related transplantation of organs and tissues, since in this case, as a rule, 3-4 antigens out of 6 coincide. Therefore, a lower dose of immunosuppressive drugs is required. The best survival rate is demonstrated by liver transplantation. Practice shows that the organ demonstrates more than ten years of survival after surgery in 70% of patients. With prolonged interaction between the recipient and the graft, microchimerism occurs, which makes it possible over time to gradually reduce the dose of immunosuppressants down to complete refusal from them.
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Introduction
1.1 Historical aspects of the development of transplantology as a science
2.4 Possible solutions problems of donor organ shortage
2.5 Problems of transplantology in a religious aspect
Conclusion
Bibliography
Introduction
The relevance of research. Transplantation of human organs and (or) tissues is a means of saving lives and restoring people’s health.
Transplantology is a branch of medicine that studies the problems of transplantation of organs and tissues, such as kidneys, liver, heart, bone marrow, etc., as well as the prospects for creating artificial organs.
Every year, 100 thousand organ transplants and more than 200 thousand human tissue and cell transplants are performed worldwide. Of these, up to 26 thousand are kidney transplants, 8-10 thousand - liver, 2.7-4.5 thousand - heart, 1.5 thousand - lungs, 1 thousand - pancreas. The leader among countries in the world in the number of transplants performed is the United States: every year American doctors perform 10 thousand kidney transplants, 4 thousand liver transplants, 2 thousand heart transplants. In Russia, 4-5 heart transplants, 5-10 liver transplants, and 500-800 kidney transplants are performed annually. This figure is hundreds of times lower than the need for these operations.
Nowadays, the topic of organ and tissue transplantation is very relevant, as it affects moral and ethical, as well as economic problems.
The purpose of the course research. Consider the main problems of organ and tissue transplantation, such as legislative, moral and ethical. The work will also examine the historical aspects of the emergence of transplantology as a science and the prospects for its development.
Research objectives:
1. Characterize the historical aspects of the development of transplantology as a science.
2. Consider the features of the procedure for organ and tissue transplantation.
3. Study the main problems of organ and tissue transplantation such as: the problem of organ retrieval, declaring the death of a person, the distribution of donor organs, the shortage of donor organs, as well as the problem of transplantation from the point of view of religion.
Object of study: organ and tissue transplantation in the modern era.
Subject of research: the contribution of scientists from different countries to the development of science, donor-recipient, human immune system, use of immunosuppressive therapy, types of transplants.
Research methods: theoretical analysis, synthesis of the obtained data.
Chapter 1. General information about transplantology
This chapter will discuss issues related to the history of transplantation, the contribution of domestic and foreign scientists to the development of this science, and also discuss basic information about the process of organ and tissue transplantation.
1.1 Historical aspects of the emergence of transplantology as a science
The idea of replacing body parts that have become unusable, like parts in a mechanism, arose a long time ago. According to the apocrypha, in the 3rd century, Saints Cosmas and Damian successfully transplanted the leg of a recently deceased Ethiopian into their patient. True, they were assisted by angels. The topic of transplantation also fascinated writers: Professor Preobrazhensky transplanted endocrine glands, Doctor Moreau sewed on animal heads to his patients, and Professor Dowell sewed on the heads of corpses.
At the beginning of the last century, a donor cornea was successfully transplanted into a person for the first time. However, the spread of other organ transplants has been hampered by a lack of knowledge about immunity. The body rejects the transplanted organ if it is not from a genetically identical organism. The Bolognese Renaissance surgeon Gaspar Tagliacozzi (1545-1599), who successfully performed autologous skin transplantations, noted back in 1597 that when a fragment of someone else’s skin is transplanted into a person, rejection always occurs
Only by the middle of the 20th century did scientists discover the mechanisms of immune reactions and learn to suppress them so that the donor organ would take root normally. Despite this, forced suppression of the immune response remains an important problem in transplantations: firstly, after an organ transplant, the recipient becomes vulnerable to infections, and secondly, steroids used to suppress immunity have severe side effects. In recent years, alternative methods of suppressing the immune system without the use of steroids or reducing their dose have begun to be developed and used - for example, scientists at Northwestern University and the University of Wisconsin are working on this issue. Today, transplantations of skin, kidney, liver, heart, intestines, lungs, pancreas, bones, joints, veins, heart valves, and corneas are well established. In 1998, a hand was successfully transplanted for the first time. Recent advances include the first partial face transplant in France in 2005 and a penile transplant in China in 2006. The world leader in transplantations is the United States: per million inhabitants, 52 kidney transplants, 19 liver transplants, and 8 heart transplants are performed annually.
The history of organ transplantation goes far into the past: for example, back in 1670, Macrain tried to transplant a dog bone into a person; in 1896, Guard proposed the terms auto-, homo-, re- and heterotransplantation. Currently, these terms have changed and the transplantation of one's own tissues is called replantation or autotransplantation, the transplantation of tissues and organs within one species is called allotransplantation, and the transplantation of tissues and organs between different species is xenotransplantation.
In 1912, French surgeon Alex Carrel proposed the use of a donor arterial patch in organ transplantations and was awarded Nobel Prize for experimental work in the field of transplantation. In 1923, the Russian scientist Elansky performed skin grafts taking into account blood type.
The modern era of transplantation began in the 1950s, but the foundation was laid earlier. So in 1943-1944. At Oxford, Peter Medvar and his colleagues concluded that the rejection reaction is a manifestation of actively acquired immunity. For a set of works on studying the rejection reaction and neonatal tolerance during organ and tissue transplantation, he was awarded the Nobel Prize.
On February 23, 1946, at the Balashikha Fur Institute, Vladimir Petrovich Demikhov performed the first experimental transplantation extra heart. In the USA, surgeon Welch began to carry out regular experiments on liver transplantation in dogs only in 1955. On December 23, 1954 in Boston (USA) by plastic surgeon Joseph Murray ( Nobel laureate 1991) the world's first successful related kidney transplant from a homozygous twin was performed.
On March 1, 1963, in Denver, American surgeon Thomas Starzl made the world's first attempt at human liver transplantation. A second liver transplant was performed in May 1963, and the patient lived for 3 weeks.
An important event subsequent progress in organ transplantation was the legalization in London in 1966 of the concept of brain death. In 1968, the criteria for brain death were clearly defined at Harvard Medical School, and in 1976 they were published in London. Since 1970, organ retrieval from brain-dead donors has become a routine procedure in most countries of the world.
On December 3, 1967, Christian Bernard performed a heart transplant in Cape Town. The recipient was a 54-year-old man with coronary heart disease and post-infarction left ventricular aneurysm, the donor was a 25-year-old woman who died as a result of a traumatic brain injury.
In 1968, Denton Coley in Houston performed the world's first cardiopulmonary complex transplant, but the patient died 24 hours after the operation. The first successful lung transplantation in a patient with silicosis was performed in Ghent by the Belgian surgeon Fritz Der in 1968.
The patient lived for 10 months.
Further progress in organ transplantation was associated with the discovery in 1976 of cyclosporine A, a drug with selective immunosuppressive activity.
Despite the historical leadership in clinical and experimental transplantation, in Russia this branch of medicine began to develop only in the mid-60s of the last century. In 1965 B.V. Petrovsky performed the first successful kidney transplant from a related donor.
Currently, organ and tissue transplantation, as well as organ donation in Russia, is regulated by the Law of the Russian Federation “On Transplantation of Human Organs and (or) Tissues” of 1992.
Looking through the chronology of the development of transplantology, it is clear that scientists have long tried to use organ transplantation as a way to prolong a person’s life, the possibility of high-quality and full life human in connection with the replacement of organs that have lost their function. But along the way, various problems arose that remain relevant to this day. For example, the search for a donor, the distribution of donor material between recipients, the commercialization of the issue, as well as the ethical side of the issue. But nevertheless, transplantology as a science continues to develop and improve.
1.2 Features of the procedure for organ and tissue transplantation
Organ transplantation (transplantation) is the removal of a viable organ from one individual (donor) and its transfer to another (recipient). If the donor and recipient belong to the same species, they speak of allotransplantation; if to different ones - about xenotransplantation. In cases where the donor and patient are identical twins or representatives of the same inbred line of animals, we're talking about about isotransplantation.
Xeno- and allografts, unlike isografts, are subject to rejection. The mechanism of rejection is undoubtedly immunological, similar to the body’s reaction to the introduction of foreign bodies. Isografts taken from genetically related individuals are usually not rejected.
In experiments on animals, almost all vital organs were transplanted, but not always with success. Vital organs are those without which preserving life is almost impossible. Examples of such organs are the heart and kidneys. However, a number of organs, say the pancreas and adrenal glands, are usually not considered vital, since the loss of their function can be compensated replacement therapy, in particular the administration of insulin or steroid hormones.
A person is transplanted kidneys, liver, heart, lungs, pancreas, thyroid and parathyroid gland, cornea and spleen. Some organs and tissues, such as blood vessels, skin, cartilage or bone, are transplanted to create a scaffold on which new recipient tissue can form.
The organ transplant procedure always involves the removal of donor organs and tissues from either living or deceased donors.
Organ removal from a living donor for transplantation is often practiced in kidney transplants; For normal functioning The remaining kidney is sufficient for the urinary system.
The consent of a close relative of the patient to become a donor radically reduces the risk of transplant rejection. The recipient's closest relatives - parents, sisters or brothers - are genetically close to him; therefore, the likelihood of the transplant recipient's immune system recognizing it as foreign is reduced. In addition, in this case there is no need for the rush that is inevitable when transplanting organs removed from a dead donor, which allows for more careful preparation and planning of the operation.
In transplantology there is such a thing as organ preservation.
In any vital organ intended for transplantation, if it is deprived of blood and oxygen for a long time, irreversible changes occur that prevent its use. For the heart this period is measured in minutes, for the kidney - in hours. Research is being spent on developing ways to preserve these organs after they are removed from the donor's body. great effort. Limited but encouraging success has been achieved by cooling the organs, supplying them with pressurized oxygen, or perfusing them with cooled tissue-preserving buffer solutions. A kidney, for example, can be preserved in such conditions outside the body for several days. Organ preservation increases the time available for selecting a recipient through compatibility testing and ensures the suitability of the organ. Currently existing regional, national and even international programs involve the procurement and distribution of cadaveric organs, allowing for their optimal use.
The main problem of transplant surgery and the cause of most complications directly or indirectly caused by organ transplantation is graft rejection. The body's powerful immune system protects it from the invasion of pathogenic bacteria and viruses. Foreign bodies that have entered the body are recognized by the immune system by their chemical structure, which is not characteristic of the body. Unfortunately, when the transplanted organ comes into contact with cells of the immune system, they begin to fight the transplant as if it were a source of infection.
That is why, before proceeding with an organ transplantation operation, close attention is paid to assessing the compatibility of the tissues of the donor organ with the tissues of the recipient’s body. The procedure is similar to determining blood group; Human tissues also come in different types. Tissue typing is done by examining white blood cells; Blood groups are determined by the more numerous red blood cells.
In addition to checking the blood type and tissue type of the donor, there are many ways to prevent rejection. It has been established, for example, that the more often the recipient has undergone blood transfusions, the less likely the risk of rejection.
The essence of the preventive effect is that the immune system, which has repeatedly resisted foreign red blood cells from donor blood, has become more tolerant to it, which explains the reduced risk of transplant rejection.
Targeted prevention of rejection involves prescribing powerful immunosuppressants - drugs that suppress the immune system and, thus, reduce the body's resistance to foreign organisms and cells. The use of immunosuppressants is a double-edged sword, because the body, having acquired tolerance to the donor organ, loses full immune protection against bacterial, viral and fungal infections. Therefore, when caring for patients taking drugs in this group, all possible measures should be taken to prevent infection and timely detection infectious diseases, special attention Required by rare infections.
Organ transplantation requires a healthy donor organ. The fact that a person is given two kidneys by nature makes it possible to transplant a kidney from a living donor into approximately one third of recipients. Other transplants require a cadaveric organ. The shortage of cadaveric organs severely limits organ and tissue transplantation, as only brain-dead (heart-beating) donors are acceptable, and only about 1% of dying patients meet current donor selection criteria.
Cadaveric organ donors are previously healthy people who have suffered irreversible brain damage as a result of a disaster. A history of injury or disease of the organ being considered for transplantation excludes the latter. All oncological diseases, with the exception of a primary brain tumor, automatically excludes the patient as a possible donor. Untreated systemic bacterial, fungal or viral infection is also a contraindication to donation. However, donors with adequately treated infections may be suitable. Prolonged ischemia caused by profound hypotension or cardiac arrest may cause certain organs unacceptable for transplantation. Patients with a long history of hypertension, diabetes mellitus and cardiovascular disease should be examined more carefully. The patient's age is a relative contraindication. Due to the lack of perfect criteria, the purpose of donor screening is to identify those donors whose functional organs may be transplanted and exclude from further consideration those whose organs are not expected to function adequately. Due to ever-increasing demand, the limits of organ acceptability are constantly being revised. Different organs are affected differently by age and disease. Therefore, when assessing a donor, organ-specific criteria are used.
Thus, in the process of developing and improving transplantology as a science, as well as new scientific discoveries have made organ transplant surgery safer and more predictable. Many thousands of patients now have hope for recovery. Despite this, transplant doctors are faced with many other problems every time, such as ethics, the power of laws, etc.
Chapter 2. Problems of organ and tissue transplantation in the modern era
transplantology organ death donor
Despite the need for organ transplant operations, transplantation is constantly faced with a number of problems relating to life and health, as well as human moral principles. The next chapter will look at the main problems that doctors and patients have to solve.
2.1 The problem of collecting organs and tissues
Ethical and legal issues of transplantation concern the justification and unjustification of transplanting vital organs in the clinic, as well as the problems of taking organs from living people and corpses. Organ transplantation is often associated with great risk for the lives of patients, many of the relevant operations are still in the category of treatment experiments and are not included in clinical practice.
Organ transplantation from a living donor is associated with harm to his health. In transplantology, compliance with the ethical principle of “do no harm” in cases where the donor is a living person turns out to be almost impossible. The doctor faces a contradiction between the moral principles of “do no harm” and “do good.” On the one hand, organ transplantation (for example, a kidney) is saving a person’s life, i.e. is good for him. On the other hand, the health of the living donor of this body significant harm is caused, i.e. the principle of “do no harm” is violated and harm is caused. Therefore, in cases of living donation, it is always about the degree of benefit received and the degree of harm caused.
According to Russian legislation, only a relative of the recipient can act as a living donor, and a mandatory condition for both the donor and the recipient is voluntary informed consent for transplantation.
The most common type of donation today is the removal of organs and (or) tissues from a dead person. This type Donation is associated with a number of ethical, legal and religious problems, among which the most important are: the problem of ascertaining the death of a person, the problem of voluntary expression of will to donate one’s own organs after death for transplantation, the permissibility of using the human body as a source of organs and tissues for transplantation from the position of religion. Solutions to these problems are reflected in a number of ethical and legal documents at the international, national and religious levels.
The motto of modern transplantology is: “When leaving this life, do not take your organs with you. We need them here." However, during life, people rarely leave orders for the use of their organs for transplantation after their death. This is due, on the one hand, to the legal norms in force in a particular country for the collection of donor organs, on the other hand, to subjective reasons of an ethical, religious, moral and psychological nature.
Currently, in the world in the field of human organ and tissue donation, there are three main types of organ collection from a corpse: routine removal, removal in accordance with the principle of the presumption of consent and removal in accordance with the principle of the presumption of a person’s disagreement to the removal of organs from his body after his death.
Routine organ harvesting is based on the recognition of the body after a person's death as the property of the state and therefore it can be used for research purposes, for the collection of organs and tissues and other purposes in accordance with the needs of the state. This type of attitude towards the human body and the type of collection of organs and tissues for subsequent transplantation took place in our country until 1992. Currently, in the world, the removal of organs from a corpse is carried out in accordance with the principles of the presumption of consent or the presumption of disagreement.
The principle of presumption of consent is the recognition of a person’s initial consent to any action. If a person does not agree to carry out the proposed actions, then he must express his disagreement in the prescribed form.
Removal of organs and tissues from a corpse is not allowed if the health care institution at the time of removal was informed that during life this person, or his close relatives or legal representative, declared their disagreement with the removal of his organs or tissues after death for transplantation to a recipient. Thus, this principle allows for the taking of tissues and organs from a corpse if the deceased person or his relatives have not expressed their disagreement.
The principle of presumption of disagreement is the recognition of a person’s initial disagreement with any action. If a person agrees to perform the proposed actions, then he must express his consent in the prescribed form.
Obtaining the consent of a person or his relatives to use his organs for transplantation is associated with a number of ethical and psychological problems. Obtaining consent from a person in a terminal condition is almost impossible for both ethical and medical reasons, because a person, as a rule, is physically in a state where he cannot make voluntary, responsible decisions based on complete and reliable information provided to him in accessible form. Communication with the relatives of a dying or just deceased person is also an extremely difficult and responsible ethical and psychological task.
2.2 The problem of ascertaining the death of a person
When collecting donor organs from a corpse, the first problem that arises is establishing the moment of possible organ collection.
The problem of ascertaining the death of a person at the end of the 20th century. moved from the category of purely medical problems to the category of bioethical ones in connection with the development of resuscitation, transplantology and other medical technologies. Depending on what condition human body is recognized as the moment of his death as a person, it becomes possible to stop maintenance therapy, take measures to remove organs and tissues for their further transplantation, etc.
In the vast majority of countries in the world, brain death is recognized as the main criterion for human death. The concept of brain death was developed in neurology after the description of the state of extreme coma by French neurologists P. Molar and M. Goulon. This concept is based on the understanding of human death as a state of irreversible destruction and (or) dysfunction of critical systems of the body, i.e. systems that are irreplaceable by artificial, biological, chemical or electronic technical systems, and such a system is only the human brain. Currently, the concept of “brain death” means the death of the entire brain, including its stem, with an irreversible state of unconsciousness, cessation of spontaneous breathing and the disappearance of all brainstem reflexes.
In our country, the fact of a person’s death is established based on a number of signs in accordance with Order of the Ministry of Health of the Russian Federation No. 73 of March 4, 2003 and the instructions of the Ministry of Health of the Russian Federation for ascertaining the death of a person based on a diagnosis of brain death. The order says: “Brain death is manifested by the development of irreversible changes in the brain, and in other organs and tissues partially or completely; biological death is expressed by posthumous changes in all organs and systems that are permanent, irreversible, cadaverous character" The instructions define: “Brain death is the complete and irreversible cessation of all brain functions, recorded with a beating heart and artificial ventilation. Brain death is equivalent to human death” (paragraph 1). The diagnosis of “brain death” is established on the basis of a whole set of signs (clinical tests) specified in this instruction.
The history of domestic transplantology has already included the “case of transplant doctors,” which to this day causes debate, does not have a final decision (court decisions have been revised several times) and, therefore, has a negative impact on the practice of organ transplantation. The situation that has become a “case” is quite typical for healthcare practice: a patient is admitted to the hospital by ambulance with a diagnosis of “traumatic brain injury” and his condition is characterized as incompatible with life. In a hospital setting, the patient goes into cardiac arrest three times. After the third cardiac arrest, resuscitation measures are ineffective, and a decision is made to remove his kidney for transplantation. The actions of the medical workers were interrupted by law enforcement officials, and the patient died.
An analysis of this situation from the perspective of biomedical ethics shows, first of all, the moral vulnerability of the criterion of “brain death” as the death of a person and the need for a very responsible attitude towards the implementation of each point of any instruction, no matter how insignificant or “bureaucratic” it may seem.
2.3 The problem of donor organ distribution
It is relevant all over the world and exists as a problem of shortage of donor organs. The allocation of donor organs in accordance with the principle of equity is decided by including recipients in a transplant program based on the practice of “waiting lists”. “Waiting lists” are lists of patients who need a transplant of a particular organ, indicating the characteristics of their health condition. The problem is that a patient, even in a very serious condition, may be at the top of this list and never wait for a life-saving operation. This is due to the fact that from the available volume of donor organs it is very difficult to select an organ suitable for a given patient due to immunological incompatibility. This problem is being solved to a certain extent by improving the methods of immunosuppressive therapy, but still remains very relevant.
So, the main criterion influencing the doctor’s decision is the degree of immunological compatibility of the donor-recipient pair. In accordance with it, an organ is given not to someone who has a higher or lower position, not to someone who has more or less income, but to someone to whom it is more suitable in terms of immunological indicators. This approach is similar to how blood transfusion is performed.
The immunological and biological data of a person in need of an organ transplant are entered into a database. Waiting lists exist at different levels, for example in large cities such as Moscow, at the regional, regional and even national levels.
On the other hand, there is a database of donor organs and their immunological parameters. When a donor organ becomes available, its biological data begins to be compared with the biological parameters of people on the waiting list. And with whose parameters the organ is compatible, it is given to him. This distribution principle is considered the most fair and is completely justified from a medical point of view, because helps reduce the likelihood of organ rejection.
But what if the donor organ is suitable for several recipients on the list? In this case, the second criterion comes into play - the criterion of the severity of the recipient. The condition of one recipient allows one to wait another six months or a year, and the other no more than a week or a month. The organ is given to the one who can wait the least. Usually this is where the distribution ends.
In a situation where the organ is almost equally suitable for two recipients, and they are both in critical condition and cannot wait long, the decision is made based on the priority criterion. The physician must take into account the length of time the recipient has been on the waiting list. Preference is given to those who are on the waiting list earlier.
In addition to the three mentioned criteria, the distance, or rather the distance of the recipient from the location of the donor organ, is also taken into account. The fact is that the time between organ removal and transplantation is strictly limited; the organ with the shortest time for transplantation is the heart, about five hours. And if the time spent covering the distance between the organ and the recipient is longer than the “life” of the organ, then the donor organ is given to the recipient located at a closer distance. Thus, the main criteria for the distribution of donor organs according to their importance: the first, main one is the degree of immunological compatibility of the donor-recipient pair, the second is the severity of the recipient and the third is the priority.
2.4 Solving the problem of shortage of donor organs
The problem of the shortage of donor organs is being solved in the following ways: organ donation is being promoted after the death of a person with lifetime consent for this, artificial organs are being created, methods are being developed for obtaining donor organs from animals, by cultivating somatic stem cells with the subsequent obtaining of certain types of tissues, creating artificial organs based on achievements of bioelectronics and nanotechnology.
The creation and use of artificial organs is the first direction in transplantology, which began to solve the problem of organ shortage and other problems associated with the collection of organs from humans, both living and dead. IN medical practice the apparatus is widely used " artificial kidney", artificial heart valves have entered the practice of cardiotransplantology, artificial hearts are being improved, artificial joints and eye lenses are being used. This is a path that depends on the latest achievements in the field of other sciences (technical, chemical-biological, etc.), requiring significant economic costs, scientific research and testing.
Xenotransplantology is currently one of the ways to solve the problem of donor organ shortage. The idea of using animals as donors is based on the belief that an animal is a less valuable living organism than a human. This is objected to by both animal welfare supporters and representatives of transhumanism, who believe that every living being has the right to life and that it is inhumane to kill another in order to continue the life of one living being. At the same time, people have been killing animals for many thousands of years to satisfy their needs for food, clothing, etc. .
The greatest problems arise in the field of solving scientific and medical problems associated with the danger of transfer to the human body various infections, viruses and immunological incompatibility of animal organs and tissues with the human body. In recent years, pigs have come to the fore as donors for xenotransplantation; they have the closest set of chromosomes to humans, the structure of internal organs, reproduce quickly and actively, and have long been domestic animals. Advances in the field genetic engineering made it possible to obtain a variety of transgenic pigs that have a human gene in their genome, which should reduce the likelihood of immunological rejection of organs transplanted from a pig to a human.
A significant ethical and psychological problem is the individual’s acceptance of an animal’s organ as one’s own, the awareness of one’s body as integral, truly human, even after transplantation of any animal organ into it.
Therapeutic cloning of organs and tissues is the possibility of creating donor organs based on the use of genetic technologies. Research on human stem cells has opened up the prospects for medicine to obtain donor organs and tissues through the cultivation of somatic stem cells. Currently, experiments are being actively carried out to obtain artificial conditions cartilage, muscle and other tissues. The route is very attractive from an ethical point of view, since it does not require invading any organism (living or dead) in order to remove organs from it. Scientists see great prospects for this way of obtaining donor organs and tissues of the human body, since it opens up the possibility of not only obtaining the organs and tissues themselves, but also solving the problem of their immunological compatibility, because The starting material is the somatic cells of the person himself. Thus, the person himself becomes both a donor and a recipient, which eliminates many ethical and legal problems of transplantation. But this is the path of experiments and scientific research, which, although they bring some encouraging results, are still far from being implemented in healthcare practice. These are technologies of the future, because... they are based on the use of stem cell cultivation technologies necessary for a person fabrics, which is currently a problem also in the research and development stage.
2.5 The problem of transplantology in the religious aspect
The Russian Orthodox Church in the “Fundamentals of a Social Concept” noted that modern transplantology makes it possible to provide effective assistance to many patients who were previously doomed to inevitable death or severe disability. At the same time, the development of this field of medicine, increasing the need for necessary organs, gives rise to certain moral problems and may pose a danger to society. The Church believes that human organs cannot be considered as an object of purchase and sale. Organ transplantation from a living donor can only be performed through voluntary self-sacrifice to save the life of another person. In this case, consent to explantation (organ removal) becomes a manifestation of love and compassion. However, the potential donor must be fully informed about possible consequences explantation of an organ for its health. Explantation is morally unacceptable, directly life-threatening donor. It is unacceptable to shorten the life of one person, including withholding life-sustaining procedures, in order to prolong the life of another. Posthumous organ and tissue donation can be an expression of love that extends beyond death. This kind of donation or bequest cannot be considered the responsibility of a person. The so-called presumption of consent of a potential donor to the removal of organs and tissues of his body, enshrined in the legislation of a number of countries, is considered by the Church to be an unacceptable violation of human freedom.
Most Western Christian theologians are supporters of transplantation and positively assess the fact of removal and transfer of a deceased organ into the body of a living person. The Roman Catholic Church believes that donation in transplantation is an act of mercy and a moral duty. The Catholic Charter of Health Professionals evaluates transplantation as a “service of life” in which there is “an offering of part of oneself, one’s blood to the flesh, so that others may continue to live.” Catholicism allows organ transplants and blood transfusions if there are no alternative treatments to save the patient's life. Donation is allowed only on a voluntary basis. Protestant theologians recognize the legitimacy of the existence of a person who receives an organ from another, but the sale of organs is considered immoral.
In Judaism, the human body is treated with great respect even after death. The body of the deceased cannot be opened. Organs can be taken for transplantation only if the person himself has authorized this before his death and the family does not object. When organ retrieval, special attention must be paid to ensure that the donor's body is not mutilated. Orthodox Jews may refuse organ transplants or blood transfusions unless the procedure is sanctioned by a rabbi. Judaism allows organ transplants when it comes to saving a human life.
In Buddhism, organ transplantation is considered possible only from a living donor, provided that it was a gift to the patient.
The Council of the Islamic Academy of Jurisprudence at its 4th session in 1988 adopted Resolution No. 26 (1/4) on the problems of organ transplantation of living and deceased persons. It states that the transplantation of a human organ from one place in the body to another is permitted if the expected benefit from the operation clearly outweighs the possible harm and if the purpose of the operation is to restore the lost organ, restore its shape or natural function, or eliminate its defect or disfigurement. that bring physical and moral suffering to a person. An essential condition for transplantation from a living donor is that the graft has the property of physical regeneration, as is the case with blood or skin, as well as the full capacity of the donor and compliance with all Shariah norms during the operation.
Sharia prohibits the transplantation of vital organs from a living person, as well as organs whose transplantation entails a deterioration in vital functions, although it does not threaten death. Organ transplantation and blood transfusions are possible only from living donors who profess Islam and give their consent. Transplantation from a person with cerebral death, who is artificially supported by breathing and blood circulation, is allowed.
Transplantation of organs from a corpse is permitted provided that life or one of the vital functions of the body depends on it, and the donor himself during his lifetime or his relatives after death have expressed consent to organ transplantation. If the identity of the deceased cannot be identified or the heirs have not been identified, then the authorized head of the Muslims gives consent to the transplantation. Thus, Shariah enshrines the principle of presumption of disagreement.
In Islam, organ transplantation on a commercial basis is strictly prohibited. Organ transplantation is permissible only under the supervision of an authorized specialized institution.
Thus, despite great promise in the field of human health care, transplantation remains largely a field of scientific research and experimentation. For most medical professionals, the ethical problems of modern transplantology are an example of solving moral problems that arise in the field of manipulation of the human body, both living and dead. This is an area of reflection about the right to dispose of one’s body, even after death, about respect for a person’s body, which is part of his human essence.
Conclusion
Currently, transplantation is one of the areas of practical healthcare. According to the 9th World Congress of Transplantology (1982), hundreds of hearts (723), tens of thousands of kidneys (64,000), etc. were transplanted. While transplant operations were few in number and were experimental in nature, they aroused surprise and even approval. 1967 is the year when K. Bernard performed the world's first heart transplant. During 1968, another 101 similar operations were performed. These years were called in the press the time of “transplantation euphoria.”
There is no doubt that transplantation of organs and tissues of the human body is a significant success modern medicine. Transplantation at this stage is a complex of medical and biological measures, which includes solving problems such as:
Elimination of biological incompatibility of tissues;
Development of techniques for performing organ and tissue transplantation;
Establishing the moment of organ removal; as well as criminal-legal and moral-ethical, aimed at protecting the rights of the donor and the patient, and preventing possible abuses by medical workers.
In transplantology, like in no other medical and biological science, it is necessary to create ethical rules and appropriate legal (legislative) regulation of the process of transplantation of biological material. On the other hand, transplantation is an established and socially recognized method of treating previously hopeless patients; it is an extreme degree of medical risk and the last hope for the patient.
The adoption of the Law “On Transplantation of Human Organs and (or) Tissues” in 1992 regulated a number of legal issues in transplantology. However, there are still quite a lot of unresolved and controversial ethical issues.
Bibliography
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2. Dzemeshkevich, S.L. Bioethics and deontology in clinical transplantology [Text]/ S.L. Dzemeshkevich, I.V. Bogorad, A.I. Gurvich; edited by IN AND. Pokrovsky. - M.: Medicine, 1997.- 140 p.
3. Law of the Russian Federation “On transplantation of human organs and (or) tissues” (dated December 22, 1992 No. 4180-1 with additions dated May 24, 2000) [Text]/Cit. according to Shamov I.A. Biomedical ethics. - M.: OJSC Publishing House Medicine, 2006. - 207 p.
4. Ivanyushkin, A.Ya. Introduction to bioethics [Text]/ A.Ya. Ivanyushkin. - M.: Philosophical thought, 2001. - 192 p.
5. Instructions for ascertaining the death of a person based on a diagnosis of brain death [Text] / Medical law and ethics, 2000. - No. 3,6-14.
6. Kerimov G.M. Sharia: The Law of Muslim Life. Answers of Sharia to the problems of our time [Text]/ G.M. Kerimov. - St. Petersburg: Dilya, 2007.- 500 p.
7. Campbell, A. Medical ethics [Text] / A. Campbell, G. Gillett. - M.: GEOTAR-Media, 2007. - 400 p.
8. Mironenko, A. Cannibalism at the end of the 20th century. Transplantology: ethics, morality, law [Text] / Medical newspaper. No. 11, November, 2000.- p. 16-17.
9. Fundamentals of the social concept of the Russian Orthodox Church. Problems of bioethics [Text] // Information bulletin of the DECR of the Moscow Patriarchate, 2000. -No. 8. pp. 73-85.
10. Organ transplantation [Electronic resource]/ Access mode: www.dic.academic.ru
11. Prokopenko, E.I. Viral infections and kidney transplantation [Text]/ Nephrology and dialysis, 2003. No. 2. - pp. 108-116.
12. Sandrikov, V.A. Clinical physiology of a transplanted kidney [Text]/ V.A. Sandrikov, V.I. Sadovnikov. - M.: MAIK Nauka/Interperiodika, 2001. - 288 p.
13. Semashko, N.A. Medical ethics [Text]/ N.A. Semashko. - St. Petersburg: ACIS, 2005. - 206 p.
14. Siluyanova, I.V. Bioethics in Russia: values and laws [Text]/ I.V. Siluyanova. - M.: Philosophical thought, 2001. - 192 p.
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16. Smirnov, A.V., Yesayan A.M. and others. Modern approaches to slowing the progression of chronic kidney disease [Text]/ Nephrology, 2004. No. 3. - pp. 89-99
17. Stetsenko, S.G. Regulation of donation as a factor in regulating transplantation [Text]/ Medical Law and Ethics, 2000 - No. 2, p. 44-53
18. Stolyarevich, E.S. On the question of the importance of specific factors in the pathogenesis of chronic transplantation nephropathy [Text]/ E.S. Stolyarevich, I.G. Kim, I.M. Ilyinsky./ Nephrology and dialysis, 2001.-№3.- P. 335-344.
19. Transplantology. Management. Ed. Academician IN AND. Shumakova. - M.: Medicine, 1995.- 391 p.
20. Fedorov, M.A. Bioethics [Text]/ M.A. Fedorov. - M.: Medicine, 2000. - 251 p.
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The successes of transplantology have shown that a new, extremely promising opportunity has opened up for humanity to treat patients who were previously considered doomed. At the same time, a whole range of legal and ethical problems arose that required the joint efforts of specialists in the field of medicine, law, ethics, psychology and other disciplines to be resolved. These problems cannot be considered solved if the approaches and recommendations developed by experts do not receive public recognition and enjoy public trust.
Organ transplantation has not become a widespread form of medical care in our country, not because the need for it is small. The reasons are different. The most important and, alas, the most prosaic - transplantation of any organ results in an amount that, I suspect, our average-income person cannot accumulate in his entire life. The state is obliged to provide this expensive treatment. But we know its capabilities.
Problem number two of modern transplantology is the shortage of donor organs in relation to Russian reality. At first glance, its simplest solution seems to be to use the organs of healthy people who accidentally died. And although, sadly, hundreds of people die from injuries every day in our country alone, ensuring organ donation is not an easy matter. Again, for many reasons: moral, religious, purely organizational.
Different countries around the world have different approaches to the procurement of donor organs. In China, it is legal to take them from the corpses of executed people. This is unacceptable for Russia. We have a moratorium on death penalty, and even before it was announced, the secrecy that shrouded this action did not allow transplantologists to see it. The acts of donating organs adopted in many countries seem much nicer and more promising than the Chinese experience. People who are young and in good health bequeath, in case they unexpectedly die, their organs to those whose lives they can save. Pope John Paul II called this kind of gift a micro-reproduction of the feat of Christ. If such acts were adopted in Russia, the collection of organs for direct donation would be much simpler, and we would be able to help incomparably more seriously ill patients.
Several years ago in Moscow, on the basis of one of the city hospitals, the only center for organ procurement in the entire metropolis was created. And if the collection of kidneys from corpses was carried out, then the removal of hearts was very bad. The Research Institute of Cardiology (now in Russia it has a monopoly on heart transplantation) received up to ten hearts a year, while, according to medical publications alone, about a thousand cardiac patients who are on the verge of life and death are waiting for them. The Moscow center practically does not deal with liver and lung retrieval, which requires the highest qualifications of transplantologists and is associated with strict time restrictions, even though no more than 600 kidney, heart, liver, and lung transplants are performed throughout Russia per year.
And when the organ is located, it is still necessary that the immuno-genetic parameters of the donor and recipient completely coincide. But this is also not a guarantee of engraftment of a transplanted heart or kidney, and therefore another problem is overcoming the risk of organ rejection. There are no unified means to prevent the rejection process yet. The world is constantly working on new immunosuppressants. And each one is better than the previous one, and each one is initially received with a bang. But as they begin to work with him, the delight subsides. All existing drugs This series is still imperfect in different ways, all have side effects, all reduce the overall immunological response, in turn causing severe post-transplant infectious lesions, and some also affect the kidneys, liver, and increase blood pressure. We have to abandon monoimmunosuppressive therapy. Have to combine different drugs, maneuver the doses of each, make compromises.
Transplantation(late lat. transplantatio, from transplanto- transplantation), tissue and organ transplantation.
Transplantation in animals and humans is the engraftment of organs or sections of individual tissues to replace defects, stimulate regeneration, during cosmetic operations, as well as for the purposes of experiment and tissue therapy. The organism from which the material for transplantation is taken is called a donor, the organism into which the transplanted material is implanted is called a recipient, or host.
Types of transplantation
Autotransplantation - transplantation of parts within one individual.
Homotransplantation - transplantation from one individual to another individual of the same species.
Heterotransplantation - a transplant in which the donor and recipient belong to different species of the same genus.
Xenotransplantation - a transplant in which the donor and recipient are related different kinds, families and even squads.
All types of transplantation, as opposed to autotransplantation, are called allotransplantation .
Transplanted tissues and organs
In clinical transplantology, autotransplantation of organs and tissues is most widespread, because With this type of transplantation there is no tissue incompatibility. Transplantations of skin, adipose tissue, fascia (muscle connective tissue), cartilage, pericardium, bone fragments, and nerves are more often performed.
Vein transplantation, especially the great saphenous vein of the thigh, is widely used in vascular reconstructive surgery. Sometimes resected arteries are used for this purpose - the internal iliac artery, the deep femoral artery.
With the introduction of microsurgical technology into clinical practice, the importance of autotransplantation has increased even more. Transplantations on vascular (sometimes nerve) connections of skin, musculocutaneous flaps, muscle-bone fragments, and individual muscles have become widespread. Transplantations of toes from the foot to the hand, transplantation of the greater omentum (fold of peritoneum) to the lower leg, and intestinal segments for esophagoplasty have become important.
An example of organ autotransplantation is a kidney transplant, which is performed for extensive stenosis (narrowing) of the ureter or for the purpose of extracorporeal reconstruction of the vessels of the renal hilum.
A special type of autotransplantation is the transfusion of the patient’s own blood during bleeding or deliberate exfusion (withdrawal) of blood from the patient’s blood vessel 2-3 days before surgery for the purpose of its infusion (administration) to him during surgery.
Tissue allotransplantation is used most often for transplantation of the cornea, bones, bone marrow, and much less often for transplantation of pancreatic b-cells for the treatment of diabetes mellitus, hepatocytes (for acute liver failure). Brain tissue transplants are rarely used (in processes accompanying diseases Parkinson's). Mass transfusion of allogeneic blood (blood of brothers, sisters or parents) and its components is a mass transfusion.
Transplantation in Russia and in the world
Every year, 100 thousand organ transplants and more than 200 thousand human tissue and cell transplants are performed worldwide.
Of these, up to 26 thousand are kidney transplants, 8-10 thousand - liver, 2.7-4.5 thousand - heart, 1.5 thousand - lungs, 1 thousand - pancreas.
The United States is the leader among the countries in the world in the number of transplantations performed: every year American doctors perform 10 thousand kidney transplants, 4 thousand liver transplants, 2 thousand heart transplants.
In Russia, 4-5 heart transplants, 5-10 liver transplants, and 500-800 kidney transplants are performed annually. This figure is hundreds of times lower than the need for these operations.
According to a study by American experts, the estimated need for the number of organ transplants per 1 million population per year is: kidney - 74.5; heart - 67.4; liver - 59.1; pancreas - 13.7; lung - 13.7; heart-lung complex - 18.5.
Transplant problems
Medical problems that arise during transplantation include problems of immunological selection of a donor, preparing the patient for surgery (primarily blood purification) and postoperative therapy that eliminates the consequences of organ transplantation. Incorrect selection of a donor can lead to the process of rejection of the transplanted organ by the recipient's immune system after surgery. To prevent the rejection process from occurring, immunosuppressive drugs are used, the need for which remains in all patients until the end of life. When using these drugs, there are contraindications that can lead to the death of the patient.
Ethical and legal issues of transplantation concern the justification and unjustification of transplanting vital organs in the clinic, as well as the problems of taking organs from living people and corpses. Organ transplantation is often associated with a great risk to the lives of patients; many of the relevant operations are still in the category of treatment experiments and have not entered clinical practice.
Taking organs from living people is associated with the principles of voluntariness and gratuitous donation, but nowadays compliance with these norms is called into question. On the territory of the Russian Federation, the law “On Transplantation of Human Organs and (or) Tissues” dated December 22, 1992 (with amendments dated June 20, 2000) is in force, prohibiting any form of organ trafficking, including those providing for a hidden form of payment in the form of any compensation and rewards. A living donor can only be a blood relative of the recipient (genetic testing is required to obtain evidence of relationship). Medical professionals are not allowed to participate in a transplant operation if they suspect that the organs have been the subject of a trade deal.
The taking of organs and tissues from corpses is also associated with ethical and legal issues: in the USA and European countries, where trade in human organs is also prohibited, the principle of “sought consent” applies, meaning that without the legally formalized consent of each person for the use of his organs and tissues the doctor has no right to remove them. In Russia, there is a presumption of consent to the removal of organs and tissues, i.e. the law allows the taking of tissues and organs from a corpse if the deceased person or his relatives have not expressed their disagreement.
Also, when discussing ethical issues of organ transplantation, the interests of resuscitation and transplantation teams of the same medical institution should be shared: the actions of the former are aimed at saving the life of one patient, and the latter - at restoring the life of another dying person.
Risk groups for transplantation
The main contraindication in preparation for transplantation is the presence of serious genetic differences between the donor and recipient. If tissues belonging to genetically different individuals differ in antigens, then organ transplantation from one such individual to another is associated with an extremely high risk of hyperacute graft rejection and loss.
Risk groups include cancer patients who have malignant neoplasms with a short period of time after radical treatment. For most tumors, at least 2 years must pass from completion of such treatment to transplantation.
Kidney transplantation is contraindicated in patients with acute, active infectious and inflammatory diseases, as well as exacerbations chronic diseases of this kind.
Patients who have undergone transplantation are also required to strictly adhere to the postoperative regimen and medical recommendations by strictly taking immunosuppressive drugs. Personality changes in chronic psychosis, drug addiction and alcoholism, which do not allow compliance with the prescribed regimen, also classify the patient as a risk group.
Requirements for donors for transplantation
The graft can be obtained from living related donors or cadaveric donors. The main criteria for selecting a transplant is compliance with blood groups (nowadays, some centers have begun to perform transplant operations without taking into account group affiliation), genes responsible for the development of immunity, as well as the approximate correspondence of the weight, age and gender of the donor and recipient. Donors must not be infected with vector-borne infections (syphilis, HIV, hepatitis B and C).
Currently, against the backdrop of a worldwide shortage of human organs, requirements for donors are being revised. Thus, dying elderly patients who suffered from diabetes mellitus and some other types of diseases began to be considered as donors more often for kidney transplants. These donors are called marginal or extended criteria donors. The best results are achieved with organ transplantation from living donors, but most patients, especially adults, do not have sufficiently young and healthy relatives who can donate their organ without harming their health. Posthumous organ donation is the only way to provide transplantation care to the majority of patients in need.
Illegal organ trade. "Black market"
According to the United Nations Office on Drugs and Crime, thousands of illegal organ transplants are performed around the world every year. The highest demand is for kidneys and liver. In the field of tissue transplantation, the largest number of operations is corneal transplantation.
First mention of the import of human organs into Western Europe dates back to 1987, when Guatemalan law enforcement discovered 30 children being targeted for use in the business. Subsequently, similar cases were registered in Brazil, Argentina, Mexico, Ecuador, Honduras, and Paraguay.
The first person arrested for illegal organ trafficking was in 1996 an Egyptian citizen who was buying kidneys from low-income fellow citizens for $12,000 apiece.
According to researchers, organ trafficking is particularly widespread in India. In this country, the cost of a kidney purchased from a living donor is 2.6-3.3 thousand US dollars. In some villages in Tamil Nadu, 10% of the population have sold their kidneys. Before the law prohibiting organ trafficking was passed, patients from wealthy countries came to India to undergo organ transplants sold by local residents.
According to statements by Western human rights activists, the organs of executed prisoners are actively used in transplantation in the PRC. The Chinese delegation to the UN admitted that such a practice exists, but this happens “in rare cases” and “only with the consent of the sentenced person.”
In Brazil, kidney transplants are performed in 100 medical centers. There is a practice here of "compensated donation" of organs, which many surgeons consider ethically neutral.
According to Serbian media reports, the forensic commission of the UN Interim Administration in Kosovo (UNMIK) revealed the fact that Albanian militants had harvested organs from captured Serbs during the Yugoslav events of 1999.
In the CIS, the most acute problem of illegal trade in human organs is in Moldova, where an entire underground kidney trade industry has been uncovered. The group made a living by recruiting volunteers who agreed to part with a kidney for $3,000 to sell in Turkey.
One of the few countries in the world where kidney trade is legally permitted is Iran. The cost of an organ here ranges from 5 to 6 thousand US dollars.
GBOU VPO Chelyabinsk State Medical Academy
Ministry of Health and Social Development of the Russian Federation
Department surgical dentistry
On the topic: "Transplantation. Types of transplantation. Modern problems. Tooth transplantation"
Completed by: student of group 370
Ponomarenko T.V.
Checked by: Assistant
Klinov A.N.
Chelyabinsk 2011
Introduction
Place of transplantation in modern surgery
Basic Concepts
Transplantation classification
Donation problems
Legal aspects
Organization of donor service
Compatibility issue
Concept of organ rejection
Autotransplantation
Allotransplantation
Xenotransplantation
Tooth transplantation: background and prospects
Autologous tooth transplantation
Tooth allotransplantation
Conclusion
Bibliography
surgery transplantology donor tooth
Introduction
The development of medicine and surgery in particular has led to the fact that the vast majority of diseases are either completely curable or long-term remission can be achieved. However, there are pathological processes at a certain stage of which it is impossible to restore the normal functions of the organ using either therapeutic or conventional surgical methods. In this regard, the question arises of replacement, transplantation of an organ from one organism to another. This problem is dealt with by such a science as transplantology.
The term "transplantology" is derived from the Latin word transplantare - to transplant and the Greek word logos - study.
The Great Medical Encyclopedia defines transplantology as a branch of biology and medicine that studies the problems of transplantation, develops methods for preserving organs and tissues, and creating and using artificial organs.
Transplantology has incorporated the achievements of many theoretical and clinical disciplines: biology, morphology, physiology, genetics, biochemistry, immunology, pharmacology, surgery, anesthesiology and resuscitation, hematology, as well as a number of technical disciplines. On this basis, it is an integrative scientific and practical discipline.
Organ transplant operations are quite complex and require special equipment. But in modern transplantology, the issues of technical performance of the operation, anesthesiological and resuscitation support have been fundamentally resolved. Continuous improvement of medical technologies for transplantation purposes has significantly expanded the practice of transplantation and increased the need for donor organs. In this area of medicine, more than in any other, moral, ethical and legal issues are acute.
1. Place of transplantation in modern surgery
The fundamentals of transplantology presented above clearly indicate its key importance for reconstructive surgery.
Back in the 18th century, the great German poet and naturalist Johann Wolfgang Goethe defined surgery as follows: “Surgery is a divine art, the subject of which is the beautiful and sacred human image. It must ensure that the wonderful proportionality of its forms, somewhere disturbed, again was restored."
When comparing volume and character surgical interventions At different historical stages of the development of surgery, one interesting pattern emerges.
Surgery in the first half of the 19th century, when scientific surgery was born, not to mention earlier periods, was characterized by operations related to various deletions: organs, parts of organs, parts of the body. These operations, aimed at removing pathological foci, saving the lives of patients, left various defects, including the loss of body parts. Such operations were dominant in the 19th century, far superior to operations of a restorative nature. It is no coincidence that medical historians call the 19th century the century of amputations.
In the process of development of operative surgery, the ratio between operations associated with removals and operations of a reconstructive nature gradually changes in favor of the latter.
It is in this process that surgical transplantology is the main methodological basis.
Usage various types tissue and organ transplantation led to the formation of such areas of reconstructive surgery as reconstructive and plastic surgery.
Four specific problems solved by modern reconstructive surgery have been formulated:
strengthening organs and tissues;
replacement and correction of defects in organs and tissues;
organ reconstruction;
organ replacement.
The solution to these problems is carried out through the development of new types and methods of operations of a restorative nature. Already, such operations predominate over operations associated with various removals, although they are also necessary and are constantly being improved.
If we talk about the future of operative surgery, it is largely connected with transplant surgery.
2. Basic concepts
Transplantology is a science that studies the theoretical background and practical possibilities of replacing individual organs and tissues with organs or tissues taken from another organism.
A donor is a person from whom an organ is taken (removed), which will subsequently be transplanted into another body.
A recipient is a person into whose body a donor organ is implanted.
Transplantation is an operation to replace the patient's tissues or organs with his own tissues or organs, or taken from another organism or created artificially.
A transplant is a transplanted area of tissue or organ.
Transplantation consists of two stages: taking an organ from the donor’s body and implanting it into the recipient’s body. Transplantation of organs or tissues can only be carried out when other medical means cannot guarantee the preservation of the recipient's life or restoration of his health. The list of transplantation objects was approved by the Ministry of Health of the Russian Federation together with the Russian Academy of Medical Sciences. This list does not include organs, their parts and tissues related to human reproduction (egg, sperm, ovaries or embryos), as well as blood and its components.
In transplantology, three outwardly similar terms are used: “plasticity,” “transplantation,” and “replantation.” It can be difficult to distinguish them absolutely, but nevertheless these terms can be defined as follows.
Plastic surgery is the replacement of a defect in an organ or anatomical structure with grafts without suturing blood vessels. The term is used to refer to the transplantation of tissues, but not entire organs.
A transplant is the transplantation (replacement) of an organ with stitching of blood vessels.
A transplant is the transplantation of a donor organ without removing the same organ from the recipient.
The term “replantation” stands somewhat apart in the system of basic terms of transplantology, which is understood as a surgical operation to engraft a section of tissue, organ or limb separated due to injury in its original place. The same term refers to the implementation extracted tooth into his own alveoli.
3. Classification of transplants
By type of transplant
All transplant operations are divided into:
.transplantation of organs or complexes of organs (transplantation of heart, kidney, liver, pancreas, tooth, heart-lung complex) .tissue and cell culture transplantation (bone marrow transplantation, bone tissue, culture β- pancreatic cells, endocrine glands). By donor type Depending on the relationship between the donor and the recipient, the following types of transplantations are distinguished. .Isotransplantation - a transplant is carried out between two genetically identical organisms (identical twins). Such operations are rare because the number of identical twins is small and they often suffer from similar chronic diseases. .Allotransplantation (homotransplantation) is a transplantation between organisms of the same species (from person to person) that have different genotypes. This is the most commonly used type of transplant. It is possible to collect organs from relatives of the recipient, as well as from other people. .Xenotransplantation (heterotransplantation) - an organ or tissue is transplanted from a representative of one species to another, for example, from an animal to a person. The method has received extremely limited application (use of xenoskin - pig skin, cell culture β- porcine pancreas cells). .Explantation (prosthetics) - transplantation of a non-living, non-biological substrate. It is more often interpreted as implantation - a surgical operation of implanting structures and materials alien to the body into tissue. At the site of organ implantation .Orthotopic transplantation. The donor organ is implanted in the same place where the corresponding recipient organ was located. .Heterotopic transplantation. The donor organ is implanted not at the site of the recipient's organ, but in another area. Moreover, the recipient’s non-functioning organ can be removed, or it can remain in its usual place. 4. Problems of donation The problem of donation is one of the most important in modern transplantology. To select the most immunologically compatible donor, each recipient needs a sufficient number of donors that meet the relevant requirements for the quality of organs used for transplantation. There are two main groups of donors: living donors and non-viable donors (in this case we are talking only about allotransplantation, which makes up the bulk of all organ transplant operations). Living donors A paired organ, part of an organ and tissue may be removed from a living donor for transplantation, the absence of which does not entail an irreversible health disorder. To carry out such a transplantation, the following conditions must be met: the donor freely and consciously consents in writing to the removal of his organs and tissues; the donor is warned about possible complications for his health in connection with the upcoming surgical intervention; the donor has undergone a comprehensive medical examination and has a conclusion from a council of medical specialists for the removal of organs or tissues from him; Removal of organs from a living donor is possible if he is in a genetic relationship with the recipient. Non-viable donors Key concepts needed to understand legal and clinical aspects organ cadaveric donation and procedures for personnel are as follows: potential donor; brain death; biological death; presumption of consent. A potential donor is a patient declared dead based on a diagnosis of brain death or as a result of irreversible cardiac arrest. This category of donors includes patients with confirmed brain death or established biological death. The distinction between these concepts is explained by a fundamentally different approach to the operation of removing donor organs. Donors whose organs are harvested with the heart beating after brain death has been declared Brain death occurs with a complete and irreversible cessation of all brain functions (lack of blood circulation in it), recorded during a beating heart and mechanical ventilation. Main causes of brain death: severe traumatic brain injury; cerebrovascular accidents of various origins; asphyxia of various origins; sudden stop of cardiac activity followed by its recovery - post-resuscitation illness. The diagnosis of brain death is established by a commission of doctors consisting of a resuscitator-anesthesiologist, a neurologist, and may include specialists in additional research methods (all with at least 5 years of experience in the specialty). The protocol for establishing death is drawn up by the head of the intensive care unit, or, in his absence, by the responsible doctor on duty at the institution. The commission does not include specialists involved in organ retrieval and transplantation. “Instructions for ascertaining the death of a person based on a diagnosis of brain death” do not apply to establishing brain death in children. The diagnosis of brain death can be reliably established on the basis of clinical tests and additional examination methods (electroencephalography, angiography of the great vessels of the brain). In case of brain death, blood circulation in the organs is preserved at the time of removal, which improves their quality and the results of the transplant operation. Removal of a donor while the heart is beating makes it possible to transplant organs with low tolerance to ischemia into recipients. Donors whose organs and tissues are removed after death is declared Biological death is established based on the presence of cadaveric changes (early signs, late signs). Organs and tissues can be removed from a corpse for transplantation if there is indisputable evidence of death, recorded by a council of medical specialists. To ascertain biological death, a commission is appointed consisting of the head of the resuscitation department (in his absence, the responsible doctor on duty), a resuscitator and a forensic expert. In case of biological death, organ removal is carried out when the donor’s heart is not working. Donors with irreversible cardiac arrest are called “asystolic donors.” IN currently worldwide, “unbeatable heart” donors account for no more than 1-6% of all donors. In Russia, working with this category of donors is becoming a daily practice. 5. Legal aspects The activities of medical institutions related to the collection and transplantation of human organs and tissues are carried out in accordance with the following documents: "Fundamentals of the legislation of the Russian Federation on protecting the health of citizens." Law of the Russian Federation "On transplantation of human organs and (or) tissues." Federal Law No. 91 “On Amendments to the Law of the Russian Federation “On Transplantation of Human Organs and Tissues”. Order of the Ministry of Health of the Russian Federation No. 189 dated August 10, 1993 “On the further development and improvement of transplant care for the population of the Russian Federation.” Order of the Ministry of Health of the Russian Federation No. 58 of March 13, 1995 “On the addition to Order No. 189.” Order of the Ministry of Health and the Russian Academy of Medical Sciences No. 460 of February 17, 2002, introducing the “Instructions for ascertaining the death of a person’s brain on the basis of brain death.” The order was registered by the Ministry of Justice of the Russian Federation No. 3170, 01/17/2002. “Instructions for determining the criteria and procedure for determining the moment of a person’s death, termination of a person’s life, termination of resuscitation measures,” introduced by order of the Ministry of Health No. 73 of 03/04/2003, registered with the Ministry of Justice of the Russian Federation on 04/04/2003. The main provisions of the law on transplantation: organs can be removed from the body of a deceased person only for the purpose of transplantation; removal can be carried out when there is no preliminary information about the refusal or objections to the removal of organs from the deceased or his relatives; doctors certifying the fact of brain death of a potential donor should not be directly involved in the removal of organs from the donor or related to the treatment of potential recipients; medical workers are prohibited from any participation in organ transplant operations if they have reason to believe that the organs used have become the object of a commercial transaction; the body and body parts cannot be the object of commercial transactions. 6. Organization of donor service In large cities there are transplant centers, and organ collection centers are organized within them. Such centers can also be created at large multidisciplinary hospitals. Representatives of collection centers are monitoring the situation in intensive care units in the region, assessing the possibility of using critically ill patients for organ collection. When brain death is determined, the patient is transferred to a transplant center, where organs are removed for transplantation, or a special team goes to the site to perform organ removal in the hospital where the victim is located. Given the great need for organs for transplantation, as well as the shortage of donors observed in all economically developed countries, after declaring brain death, complex organ retrieval is usually carried out to maximize their use (multi-organ retrieval). Rules for organ retrieval: organs are removed in strict compliance with all aseptic rules; the organ is removed along with the vessels and ducts, preserving them as much as possible for the convenience of anastomosis; After removal, the organ is perfused with a special solution (currently, Euro-Collins solution is used for this at a temperature of 6-10 0 WITH); after removal, the organ is immediately implanted (if in parallel there are operations in two operating rooms to collect the organ from the donor and access or remove the recipient’s own organ) or placed in special sealed bags with Euro-Collins solution and stored at a temperature of 4-6 0 WITH. 7. Compatibility issues The problem of donor and recipient compatibility is considered the most important to ensure the normal functioning of the graft in the recipient's body. Compatibility of donor and recipient Currently, donor selection is carried out according to two main antigen systems: AB0 (erythrocyte antigens) and HLA (leukocyte antigens, called histocompatibility antigens) AB0 system compatibility During organ transplantation, it is optimal to match the blood group of the donor and recipient according to the AB0 system. A discrepancy in the AB0 system is also acceptable, but according to the following rules (reminiscent of Ottenberg’s rule for blood transfusion): if the recipient has blood type A(II), a transplant is possible only from a donor with type A(II); if the recipient has blood group B(III), a transplant from a donor with group 0(I) and B(III) is possible; if the recipient has blood group AB(IV), a transplant from a donor with group A(II), B(III) and AB(IV) is possible. Rh compatibility between donor and recipient is taken into account individually when conducting cardiopulmonary bypass and the use of blood transfusion. HLA compatibility HLA antigen compatibility is considered decisive when selecting a donor. The complex of genes that control the synthesis of the main histocompatibility antigens is located on chromosome VI. The polymorphism of HLA antigens is very wide. In transplantology, the A, B and DR loci are of primary importance. Currently, 24 alleles of the HLA-A locus, 52 alleles of the HLA-B locus and 20 alleles of the HLA-DR locus have been identified. Combinations of genes can be extremely diverse, and a match at all three of these loci at the same time is almost impossible. After determining the genotype (typing), an appropriate entry is made, for example, “HLA-A 5(antigen is encoded by sublocus 5 of locus A of chromosome VI), A 10, IN 12, IN 35, DR w6 "
Rejection in the early postoperative period is usually associated with HLA-DR incompatibility, and in the long term - with HLA-A and HLA-B. Cross typing In the presence of complement, several samples taken are tested. different time samples of recipient serum with donor lymphocytes. The result is considered positive when the cytotoxicity of the recipient's serum towards the donor's lymphocytes is detected. If in at least one case of cross-typing the death of the donor's lymphocytes is detected, transplantation is not performed. Matching donor to recipient In 1994, a method of prospective genotyping of “waiting list” recipients and donors was widely introduced into clinical practice. Donor selection is an important prerequisite for effectiveness clinical transplants. “Waiting list” is the sum of all information characterizing a given number of recipients; an information bank is formed from it. The main purpose of the “waiting list” is the optimal selection of a donor organ for a specific recipient. All selection factors are taken into account: AB0 group and preferably Rh compatibility, combined HLA compatibility, cross typing, seropositivity cytomegalovirus infection, hepatitis, control for HIV infection and syphilis, constitutional characteristics of the donor and recipient. Currently, there are several banks with data on recipients in Europe (Eurotransplant). When a donor appears from whom organ removal is planned, he is typed using the AB0 and HLA systems, after which he is selected with which recipient he is most compatible. The recipient is called to the transplant center, where the donor is located or where the organ is delivered in a special container, and the operation is performed. 8. The concept of organ rejection Despite the measures taken to select the most genetically similar donor for each recipient, it is impossible to achieve complete genotype identity; recipients may experience a rejection reaction after surgery. Rejection is an inflammatory lesion of a transplanted organ (graft) caused by a specific reaction of the recipient's immune system to the donor's transplantation antigens. Rejection occurs less often, the more compatible the recipient and donor are. Rejection is distinguished: .hyperacute (at operating table);
.early acute (within 1 week); .acute (within 3 months); .chronic (delayed in time). Clinically, rejection is manifested by a deterioration in the functions of the transplanted organ and its morphological changes(according to biopsy). A sharp deterioration in the recipient's condition, associated with an increase in the activity of the immune system in relation to the transplanted organ, is called a “rejection crisis.” To prevent and treat rejection crises, patients after transplantation are prescribed immunosuppressive therapy. Basics of Immunosuppression To reduce the activity of the immune system and prevent organ rejection after transplantation operations, all patients undergo pharmacological immunosuppression. In uncomplicated cases, relatively small doses of drugs are used according to special regimens. With the development of a rejection crisis, the dose of immunosuppressants is significantly increased and their combination is changed. It should be remembered that immunosuppression leads to a significant increase in the risk of infectious postoperative complications. Therefore, aseptic precautions must be observed especially carefully in transplant departments. The following drugs are mainly used for immunosuppression. Cyclosporine is a cyclic polypeptide antibiotic of fungal origin. Suppresses the transcription of the interleukin-2 gene, necessary for the proliferation of T-lymphocytes, and blocks T-interferon. Generally immunosuppressive effect selective. The use of cyclosporine ensures good graft survival with a relatively low likelihood of infectious complications. Sirolimus is a macrolide antibiotic that is structurally related to tacrolimus. Suppresses regulatory kinase (“target of sirolimus”) and reduces cell proliferation in the cell division cycle. Acts on hematopoietic and non-hematopoietic cells. Used in basic immunosuppression as a main or additional component. There is no need to constantly monitor the concentration of the drug in the blood. Possible complications of the drug: hyperlipidemia, thrombotic microangiopathy, anemia, leukopenia, thrombocytopenia. Azathioprine. In the liver it is converted into mercaptopurine, which inhibits the synthesis of nucleic acids and cell division. Used in combination with other drugs to treat rejection crises. Leuko- and thrombocytopenia may develop. Prednisolone is a steroid hormone that has a powerful nonspecific depressive effect on cellular and humoral immunity. IN pure form not used, is part of immunosuppressive regimens. In high doses it is used for rejection crises. Orthoclone. Contains antibodies to CD 3+-lymphocytes. Used to treat rejection crises in combination with other drugs. Antilymphocyte globulin and antilymphocyte sera. They were introduced into clinical practice in 1967. Currently, they are widely used for the prevention and treatment of rejection, especially in patients with steroid-resistant rejection. They have an immunosuppressive effect due to the inhibition of T-lymphocytes. In addition to the listed drugs, other agents are also used: calcineurin inhibitors, monoclonal and polyclonal antibodies, humanized anti-TAC antibodies. 9. Autotransplantation Autotransplantation ensures true engraftment of the transplanted substrate. With such transplants and plastic surgery, there is no immunological conflict in the form of graft rejection. For this reason, autotransplantation is by far the most advanced type of transplantation. In surgery, skin autoplasty is widely used: local and free autografts. To strengthen weak points and cavity wall defects, dense fascia, such as the fascia lata, is used to replace tendon defects. Some bones are used for bone autoplasty: rib, fibula, crest ilium. Some blood vessels can serve as autografts: great saphenous vein of the thigh, intercostal arteries, internal mammary arteries. The most indicative here is coronary artery bypass grafting, in which a segment of the great saphenous vein of the patient’s thigh is used to create a connection between the ascending aorta and the coronary artery of the heart or its branch. Autotransplantation is the use of autografts of thin, colon, stomach. Autoplastic surgeries are performed on the urinary tract: ureter, bladder. A very good auxiliary autoplastic material is the greater omentum. Autotransplantation may also include: replantation of a tooth, traumatically severed limbs or their distal segments: fingers, hands, feet. 10. Allotransplantation For allotransplantation, there are two sources of donor tissues and organs: a cadaver and a living volunteer donor. In modern surgery, skin allografts from both corpses and volunteer donors, various connective tissue membranes, fascia, cartilage, bones, and preserved vessels are used. An important type of allotransplantation in ophthalmology is cadaveric cornea transplantation, developed by the largest Russian ophthalmologist V.P. Filatov. The first reports of allotransplantation of the complex of skin and soft tissues of the face appeared. Allotransplantation is the transfusion of blood as liquid tissue, which is widely used in medicine. The largest area of allotransplantation is organ transplantation. For the widespread use of allotransplantation, three problems are of primary importance: legal and moral support for the collection of organs both from a corpse and from a living volunteer donor; preservation of cadaveric organs and tissues; overcoming tissue incompatibility. In the legislative support of allotransplantation, the criteria for death, in the presence of which organ retrieval is possible, legislation regulating the rules for organ and tissue retrieval, and the possibility of using allografts from living volunteer donors are of key importance. Preservation of donor organs and tissues allows transplantation material to be preserved and accumulated in tissue and organ banks for use for therapeutic purposes. The following main conservation methods are used. Hypothermia, i.e. preservation of an organ or tissue at a low temperature, at which a decrease in metabolic processes in tissues and a decrease in their need for oxygen occur. Freezing in a vacuum, i.e. lyophilization, which leads to an almost complete stop of metabolic processes while preserving cells and other morphological structures. Continuous normothermic perfusion of the bloodstream of the donor organ. At the same time, normal metabolic processes are maintained in the isolated organ by delivering oxygen and necessary nutrients to the organ and removing metabolic products. Overcoming tissue incompatibility between donor and recipient tissues is essential for allotransplantation. This problem, first of all, relates to the selection of donors, donor organs and tissues that are most compatible with the recipient’s body. It should be noted that allotransplantation and the problems associated with it are a very dynamic and rapidly developing area of clinical transplantology. 11. Xenotransplantation In modern surgery, transplantation of animal organs and tissues to humans is the most problematic type of transplantation. On the one hand, an almost unlimited number of donor organs and tissues from different animals can be prepared. On the other hand, the main obstacle to their use is pronounced tissue immune incompatibility, leading to rejection of xenografts by the recipient's body. Therefore, until the problem of tissue incompatibility has been resolved, the clinical use of xenografts is limited. In a number of reconstructive operations, specially treated animal bone tissue is used, sometimes blood vessels for combined plastic surgery, temporary transplants of the liver and spleen of a pig - the animal that is genetically closest to humans. Attempts to transplant animal organs into humans have not yet led to lasting positive results. Nevertheless, this type of transplantation can be considered promising after solving the problems of tissue incompatibility. 12. Tooth transplantation: background and prospects Attempts at tooth transplantation have been known since ancient times. This was done by the surgeon Abul Kazim, who lived in the ninth century AD. e. The famous surgeon Ambroise Paré transplanted the healthy tooth of her maid into the French princess instead of a tooth removed from her. In Russia, V. Antonevich defended his doctoral dissertation “On replantation and dental transplantation” in 1865. However, this operation was gradually almost completely abandoned both in our country and abroad due to a number of failures and postoperative complications. Archaeological excavations confirm man's constant desire to replace and restore lost teeth using a variety of materials of animal, human and mineral origin. Stones, including precious and precious metals, ivory and other materials, were used for implantation. The Thibaudie Museum at Harvard University in the United States displays a pre-Columbian human skull with precious stones implanted into the lower jaw, and the Peruvian Museum displays an Inca human skull with 32 implanted quartz and amethyst teeth. IN Ancient Egypt Before mummification, missing teeth were restored. Tooth transplantation was practiced from one person to another - the teeth of the poor were rearranged by the rich. These operations were performed by barbers (surgeons-hairdressers). In Egypt, Greece, India, Arab countries Dental implantation methods were used. In most cases, human teeth from slaves and animal teeth were used as implants, and the recipients were wealthy people. In America, the Indians used ground stones to replace a missing tooth. Attempts at dental transplantation were also made in the 20th century. But this method was not widely used for a number of reasons. Secondly, donors are needed. Thirdly, a bank is needed to store dental transplants. Fourthly, reliable sterilization of transplants is needed, guaranteeing the safety of such an operation, because When transplanting biological materials, there is a high risk of transmitting various infections. Fifthly, transplantation is very expensive. Sixthly, the results of dental transplantation ultimately turn out to be unsatisfactory. In most cases, either rejection of the transplanted teeth occurs, or their resorption as a result of an immune conflict. 13. Autologous tooth transplantation Autologous tooth transplantation - transplantation of a tooth into another alveolus. It is indicated when removing a decayed tooth. This operation is performed very rarely and is undertaken in cases where it is possible to transplant a healthy supernumerary or impacted tooth into the alveolus of a tooth removed due to chronic periodontitis or crown destruction due to acute trauma. The surgical technique is the same as for replantation. Particular difficulties in this operation lie in the formation of an alveolus for transplanting another tooth, since there is a significant difference in the size of not only the crown, but also the roots of the extracted and replanted teeth. Formation of the alveoli in accordance with the transplanted tooth often leads to additional trauma to the alveoli and removal of its periosteum, which adversely affects the healing process and is often complicated. 14. Tooth allotransplantation Tooth allotransplantation is the transplantation of a tooth or its germ, which is taken from another person, into an artificially formed bone bed or socket of an extracted tooth. Allotransplantation of teeth is of great practical interest, and therefore has long attracted the attention of experimenters and clinicians. Transplantation of dental germs is indicated in the case of the appearance (or presence from the moment of birth) of children of dental arch defects that impair the function of chewing and speech, are not amenable to orthodontic treatment and threaten to impair the growth and development of the alveolar processes, in particular: a) in the absence of a child with a shift or permanent bite two or more nearby standing teeth or their rudiments, lost as a result of previous periodontitis or trauma, with the alveolar process preserved and the absence of pronounced destructive changes in it; b) in the absence of large molars lower jaw or their rudiments in young children (6-8 years), which entails the rapid development of deformation of the alveolar process, a lag in the development of the corresponding half of the jaw; c) with congenital adentia. Based on the results of experimental studies carried out in this area by various authors the following conclusions can be drawn: ) the most favorable time for transplanting tooth germs is the period when they already have basic structures without their pronounced differentiation and formation; ) taking the embryos from the donor and transplanting them into the recipient should be carried out strictly observing the requirements of asepsis and trying to minimally injure the graft; ) the transplanted rudiments must be brought into contact with the recipient’s tissues over their entire surface, thereby ensuring strong fixation and nutrition of the sac; ) the rudiments must be isolated from oral infection with closed sutures or glue for the entire period of their engraftment and development. The experience of transplanting 16 tooth rudiments, taken from the corpses of children 4-8 years old 1-2 hours after their death as a result of an accidental injury, showed the promise of this operation: out of 16 rudiments, 14 took root and began to erupt (after 5-8 months). Crown eruption and root development were generally completed after 2-3 years, and after 4-5 years the teeth were functioning well. Encouraging results of dental allotransplantation in humans were obtained by V. S. Moroz: in 43 out of 53 patients, teeth were preserved for up to 5"/2 years; the minimum period of tooth functioning was 2 years. To achieve favorable results with tooth allotransplantation, it is necessary, in the author’s opinion, to observe following conditions: ) ensure a tight fit of the gums to the root in accordance with anatomical neck tooth; ) perform surgery only in the absence of atrophy of the gingival papillae; ) exclude traumatic impacts of the antagonist on the transplanted tooth; ) remove pathologically altered tissues surrounding the apex of the tooth in the recipient’s alveolus; According to A.P. Cherepennikova (1968), dental allotransplantation is indicated in three cases: ) with primary partial adentia as a result of the absence of the rudiments of permanent teeth; ) with fresh injuries of the jaws with loss of teeth; ) in the presence of teeth that must be removed due to the impossibility of saving them with therapeutic methods. Thus, the presented data on allotransplantation of teeth and their rudiments indicate both a certain promise of the method and the need for its improvement. 15. Bone grafting Need for bone transplant Bone transplantation is often necessary in cases of complete edentulism, which is usually accompanied by severe bone resorption. At the moment of tooth extraction or dislocation, the process of incomplete bone remodeling begins, which inevitably leads to atrophy of the alveolar ridge. A bone graft retains its structure and function even if the number of viable cells decreases. The bone matrix is gradually filled with cells from adjacent tissues in a process known as slow replacement. This mechanism does not operate when transplanting skin or mucous membranes, so in these cases, maintaining the viability of the graft cells is of paramount importance for the success of the operation. Autogenous bone grafts The most frequently performed transplantation is bone tissue, which is used to eliminate defects caused by atrophy, trauma, tumor, as well as to correct congenital deformities. Elimination of bone defects is one of the most difficult tasks in maxillofacial surgery. Improvements in methods for obtaining, storing and using grafts have become possible thanks to a better understanding of the mechanisms of bone repair. Autogenous bone graft is so far the only source of osteogenic cells and is considered the gold standard for reconstructive interventions in the oral cavity. Autografts are taken from the host bone: iliac crest, rib, small tibia, as well as fragments of the upper and lower jaw - the mandibular symphysis, retromolar region and ramus; mound upper jaw, as well as bone hyperostosis. The great advantages of autogenous grafts over other bone grafts are determined by the presence of viable osteoblasts and the absence of foreign antigenic proteins, as well as the fact that they have both osteoconductive and osteoinductive characteristics. Their only drawback, if you can call it that, is the additional trauma involved in harvesting the graft. In the first weeks after transplantation of an autogenous graft, the process of adaptation of bone, periosteal, and bone marrow cells occurs in it, followed by their revascularization. In the second phase, stimulation of the cells of the bone bed is observed, and they, differentiating into osteoblasts, create the bone matrix. Due to the bone-inductive activity of the cells of the bone bed, new bone is formed, where the transplanted autograft plays the role of the bone skeleton. Subsequently, bone resorption and new formation occur simultaneously, which leads to the incorporation of a bone graft into the host bed. Autografts can be taken from cancellous or cortical bone or be combined. If they consist of cancellous bone, then after transplantation they experience rapid and more complete revascularization. Meanwhile, in autografts consisting of cortical bone, these processes occur more slowly, and, in addition, a significant part of the transplanted bone dies, and its replacement with new bone has a creeping nature. Conclusion Why implantation and not transplantation? A tooth transplant is the transplantation of a tooth or its germ that is taken from another person. Widespread this method was not successful for a variety of reasons. First, we need donors. Secondly, a bank is needed to store dental grafts. Thirdly, reliable sterilization of transplants is needed, guaranteeing the safety of such an operation, because When transplanting biological materials, there is a high risk of transmitting various infections. And finally, the results. They are disappointing. In most cases, either rejection of the transplanted teeth occurs, or their resorption as a result of an immune conflict. Implantation is the installation or insertion of a non-biological object. The object, which is non-biological in origin, can be made from biocompatible materials that are properly sterilized to ensure patient safety. Such materials rarely cause an immune conflict. Finally, implants can be mass produced and standardized. This allows the implantation method to be widely used and accumulate required experience, which is the basis for achieving good treatment results. Bibliography Gluzman A.M., Matyash I.M.. Directory surgical operations. Kyiv "Health", 1979 Kovanov V.V.. Experiment in surgery. Moscow "Young Guard", 1989 Moore F.. History of organ transplants. Moscow "Mir", 1987 Balin V.N., Aleksandrov N.M.. Clinical operative maxillofacial surgery. Management. St. Petersburg "Special Literature" 5. Kovalenko P.P. Fundamentals of transplantology. Ed. Rostov University, 1975 Filatov A.N., Beringer Yu.V. Transplantation and replacement of tissues and organs. L., Medicine, 1990 Evdokimov A.I., Vasiliev G.A.. Surgical dentistry. Moscow "Medicine", 1964 Vinogradova T.F.. Pediatric dentistry. Moscow "Medicine" 9. Roginsky V.V. Inflammatory diseases in the maxillofacial area in children. Moscow "Detstomizdat", 1998 Petrov S.V. General surgery. Moscow "GEOTAR-Media", 2010 Kozlov V.A. Dentistry: a textbook for medical universities and postgraduate training of specialists. St. Petersburg : SpetsLit, 2011 Burian F.. Development of change of fabrics. Acta Chir., 1961 Wozney J.. The bone morphogenetic protein family and osteogenesis. Mol Reprod Develop, 1992 Collins M., Mars M..Alveolar bone grafting: A review of 115 patients. Euro J Orthod, 1998 McCarthy C. Patel RR..Dental implants and onlay bone grafts. Int J Oral Implants, 2003
