Stem cells definition. What sources of stem cells does medicine use? Use in medicine

Embryonic stem cells (ESCs) are classical stem cells because they are capable of infinite self-renewal and have multipotent differentiation potential. Their source is usually primordial germ cells, the inner cell mass of the blastocyst or individual blastomeres of 8-cell stage embryos, as well as morula cells of later stages.

Embryonic stem cells have the highest telomerase activity of all stem cell categories, which provides them with the ability to undergo unprecedented self-renewal (more than 230 cell duplications in vitro; while differentiated cells divide approximately 50 times during life).

In laboratory conditions, these cells are capable of differentiating into various types of both embryonic and adult cells. They have a normal karyotype and, under controlled conditions, can be cloned and reproduced many times without changing their properties.

Studies have shown that ESC transplantation is effective for treating pathologies that are based on dysfunction or death of specialized cell types. Thus, Parkinson's disease, caused by the progressive degeneration and loss of dopamine-producing neurons in a certain area of ​​the brain, can be successfully treated using intracerebral injection of embryonic neurons. Also, in type I diabetes mellitus (caused by a malfunction of pancreatic islet cells), implantation of pancreatic islet cells into the liver leads to normalization of glucose levels. With the help of ESC transplantation, other intractable diseases can also be treated - for example, muscular dystrophy Duchenne, Purkinje cell degeneration. ESC transplantation is also effective in cases of trauma - in particular, trauma spinal cord.

At first glance, ESCs are most suitable for use in reparative medicine. However, it is well known that when transplanted into the body, ESCs are capable of generating neoplasms - teratomas. Therefore, before using ESCs in cell therapy, it is necessary to differentiate them in the desired direction and remove cells from the ESC population that could potentially lead to the formation of teratomas. Another problem that has to be overcome when using ESCs is the need to somehow ensure their histocompatibility with the recipient’s body. Finally, it is difficult to ignore the ethical side of using human embryonic cells to obtain ESCs.

Adult stem cells

Stem cells are present in many organs and tissues of adult mammals: bone marrow, blood, skeletal muscle, dental pulp, liver, skin, gastrointestinal tract, pancreas. Most of these cells are poorly characterized. Compared to ESCs, adult stem cells have less self-renewal capacity, and although they differentiate into multiple cell lineages, they are not multipotent. Telomerase activity and, accordingly, the proliferative potential of adult stem cells are high, but still lower than that of ESCs.

It is assumed that the least differentiated stem cells are in a dormant state in the body. If necessary, an irreversible process of their gradual maturation in a certain direction of differentiation is launched.

Hematopoietic stem cells

Of the adult stem cells, hematopoietic stem cells (HSCs) are the best characterized. These are cells of mesodermal origin. They give rise to all types of hematopoietic and lymphoid cells. Normally, hematopoiesis in the body is apparently maintained mainly by a constantly changing small number of relatively short-lived cell clones. In vitro, hematopoietic stem cells, under certain conditions, are capable of self-renewal and can be stimulated to differentiate towards the same cell lineages as in vivo.

For several decades, bone marrow tissue has been successfully used for treatment various diseases blood (for example, leukemia), as well as radiation damage to the body, restoring with their help the impaired functions of the hematopoietic and lymphoid organs. This is usually done by bone marrow transplantation; V Lately Cord blood is also used. The HSC population serves as a potential source for endothelial cell precursors, which makes it possible to use HSCs for the treatment of ischemic disease and myocardial infarction.

Neural tissue stem cells

Another category of cells that is currently being intensively studied are neural stem cells (NTSCs). These cells were originally found in the subventricular zone of the embryonic brain. Until recently, it was believed that the adult brain did not contain stem cells. However, experiments on rodents and primates, as well as clinical trials involving volunteers, have shown that SCNT continue to be present in the adult brain. In vitro, neural stem cells can be “targeted” to both proliferate and differentiate into various types of neurons and glial cells (supporting and protective cells of nervous tissue). Both embryonic SCNT and adult SCNT transplanted into the brain can generate neuronal and glial cells. Although it is unknown how long it takes for neural stem cells to self-renew, they can be cultured in vitro for long periods.

Stromal progenitor cells and mesenchymal stem cells

Stromal progenitor cells and mesenchymal stem cells (MSCs) were discovered about 30 years ago. These are a kind of universal cells that are contained in the bone marrow, in a kind of depot, where they are stored “in reserve.” They are capable of intense proliferation, can differentiate into many cell types and are transplantable in vivo. If necessary, they enter the damaged organ or tissue and are transformed into the necessary specialized cells.

In vitro, the number of mesenchymal stem cells can increase 100,000-fold within 6-8 weeks, while they remain in an undifferentiated state. Each colony of stromal cells is a clone, that is, it is formed by the proliferation of one cell, which was called a colony-forming fibroblast cell (COF-F). In animals and humans under physiological conditions, the cloning efficiency of COC-F colonies remains relatively stable and is an important parameter of skeletal status, which indicates the role of COC-F in the pathophysiology of bone and bone marrow defects.

Much evidence has been obtained that, in contrast to hematopoietic stem cells, bone marrow COC-Fs ​​represent a local population, that is, they do not migrate from one part of the body to another and, accordingly, do not take root during infusion. It is a pity if this problem does not find its solution - after all, to treat such common bone diseases, such as osteoporosis or osteogenesis incomplete, where it is not possible to transplant genetically altered stromal cells into all areas of the lesions, the ability to deliver them through the circulation appears to be highly desirable. In general, the question of the possibility of stromal cell migration, as well as the factors favoring it, remains open.

Stromal progenitor cells also play a very important role, providing the specific microenvironment necessary for the proliferation and differentiation of hematopoietic and immunocompetent cells in the territory of hematopoietic and lymphoid organs. Thus, “correction” of microenvironmental disorders can, in principle, be carried out precisely through this category of cells.

Significant interest for clinical application represent mesenchymal stem cells, which are part of the population of stromal progenitor cells (or colony-forming cells of stromal fibroblasts - KOK-F) of the bone marrow. Their use began with successful treatment non-union of bone fractures propagated in cultures of autologous bone marrow stromal cells. Until now, bone repair and cartilage tissue remains one of the most important areas of application of MSCs. With the help of transplantation of these cells, it was possible to achieve success in the treatment of a severe contingent of patients with pseudarthrosis, non-union of fractures and chronic osteomyelitis, osteoarthritis. The principles of the biotechnological methods used in this case are universal and can also be used to treat patients with defects bone tissue various localizations(traumatology, orthopedics, neurosurgery, craniofacial surgery, dentistry-implantology).

As possible carriers of recombinant DNA, mesenchymal stem cells also represent a very attractive object for genetic engineering, for the treatment of a number of degenerative and hereditary diseases.

Bone marrow cells and MSCs can also be used in the treatment of coronary heart disease, lesions of the limbs and brain, as well as for the treatment of myocardial infarction. This is another area of ​​application of MSCs that is at the stage of preclinical trials. In laboratory studies in animals and in the treatment of myocardial infarction in humans, bone marrow-derived stem cells have been transplanted into the infarct area either by direct injection or through intravascular administration. As a result, it was possible to achieve a real reduction in the infarction area. However, before therapy for KS in adults can be fully implemented, additional clinical trials and well-planned studies are needed. clinical trials, which will allow us to make a final conclusion about the safety and effectiveness of the proposed method.

Of particular interest are the first data showing the possibility of using bone marrow stromal cells in repair processes in the skin. In particular, studies show that after intradermal injection of bone marrow stromal cells, the regeneration of damaged skin tissue was more orderly with less undesirable consequences, which include scar formation.

It should be noted that for the success of treatment, the key point remains right choice SC transplantation method. A number of laboratories are also currently working on improving methods for purifying SC populations and enriching them with early precursors in order to create conditions for more effective cell therapy. It is generally agreed that further laboratory research is also required to study the phenomenon of stem cell plasticity, as well as many other aspects.

As we can see, there are a lot of hopes and expectations associated with stem cells. Perhaps the time is not far off when the discovered properties of stem cells and those that are still sealed for us today will create new prospects for the treatment of a number of serious illnesses.

What makes stem cells unique?

During the development of a human embryo, a number of key events occur: fertilization of the egg is followed by the so-called. fragmentation, the essence of which comes down to the rapid accumulation of totipotent (i.e., capable of creating a whole organism, repeating embryogenesis from one cell) cellular material.

After about 12 cell divisions, this process slows down sharply, and the synchrony of divisions is disrupted. Transcription of the embryo's genome begins, that is, the implementation of hereditary information. This change, known as the midblastula transition, likely reflects the depletion of a specific maternally derived component that is used to bind to newly synthesized DNA.

Transcription ends with the accumulation of information in the form of messenger RNA in the cytoplasm of these unique primary cells, which determines further intrauterine development. The implementation of information is ultimately carried out through migration, cell specialization and the formation of the main germ layers - ectoderm (source of skin cells, central nervous system, etc.), mesoderm (source of muscle cells, bones, blood, etc.) and endoderm (source of gland cells, gastrointestinal tract etc.), what happens in the process of the so-called. gastrulation.

From this point on, each tissue retains a limited number of unspecialized cells. Such cells are called stem cells or progenitor cells; their main function is to control the process of creating the organism as a whole, transferring and implementing hereditary programs.

Stem cells are undifferentiated, immature cells of an embryo, fetus, newborn or adult organism, capable of self-renewal and differentiation into various types of tissues and organs. In the adult body, they play the role of “regeneration machines”, their goal is to maintain the morphofunctional constancy of the tissue; they have less potential than at the very beginning of embryogenesis, but are able to effectively replace damaged elements of specialized tissue in the required volume. Almost every tissue type has its own precursor cells (predifferentiated cells). True pluripotent (capable of differentiation into cells of different tissues of different germ layers) cells are extremely rare in the body under normal conditions; their isolation from an adult organism is currently not possible without the use of cloning techniques.

During the aging process, the amount of initially embedded regenerative information in cells rapidly decreases, and the number of stem cells themselves decreases. An exhausted repair system becomes ineffective - a number of diseases associated with aging arise: the skin fades, the elasticity of cartilage and bone density decreases, the vascular endothelium is damaged - blood supply deteriorates, gradually all tissues of the body fall into conditions of reduced oxygen supply, the processes of replacing functionally active tissues with inferior ones are accelerated connective stromal tissues. Exposure to a number of infections, the occurrence of congenital, hereditary and multifactorial diseases, chronic intoxication (including alcohol), and injuries also lead to similar consequences - the body is unable to cope with the growing flow of problems and gradually dies.

The success of human organ and tissue transplantation has opened new era in medicine - the fundamental possibility of replacing defective tissues and organs of a patient with donor, healthy ones has been demonstrated. Unfortunately, organ transplantation remains inaccessible and is accompanied by complex surgical interventions and requires constant and large amounts of immunosuppression.

Scientists around the world are intensively working on the problem of laboratory production of progenitor cells for the purpose of their subsequent implantation to replace dead tissue, which, according to the medical scientific community, can serve as an alternative to organ transplantation. In 1998, American scientists John Gerhart and James Thompson were the first to obtain and grow cultures of embryonic stem cells and sex progenitor cells in the laboratory, capable of completely reproducing embryogenesis. Thus, humanity has a real opportunity to grow in laboratory conditions the required amount of “spare parts” for the body and thereby correct the consequences of a number of chronic and acute diseases. Dm. Shamenkov, Ph.D.

Stem cell plasticity

Until recently, it was believed that organ-specific stem cells could only differentiate into cells of the corresponding organs. However, according to some data, this is not the case: there are organ-specific stem cells of adult animals that are capable of differentiation into cells of organs other than the organs of origin of the stem cells, even if they ontogenetically belong to different germ layers. This property of stem cells is called plasticity. Thus, there is a lot of evidence that bone marrow MSCs have broad plasticity and are capable of giving rise to some elements of nervous tissue, cardiomyocytes, epithelial cells, and hepatocytes.

An alternative hypothesis for the phenomenon of plasticity is that multipotent stem cells are present in various organs even after birth and are stimulated to specific proliferation and differentiation in response to local factors, represented by the organ into which stem cells are recruited. There is also an assumption that stem cells are recruited to damaged organs and already there they realize their plasticity properties, i.e. they differentiate in the direction necessary for their restoration.

At the same time, it should be noted that a number of scientists question the very concept of stem cell plasticity, pointing out that the corresponding experiments were performed on pure populations of tissue-specific stem cells.

Dictionary

Diploid cell(from the Greek dipluos - double and eidos - view) - a cell with two homologous (similar) sets of chromosomes. All zygotes and, as a rule, the cells of most tissues of animals and plants, except for germ cells, are diploid.

Differentiation potential- the ability to transform into various cells of the body.

Karyotype(from the Greek karyon - nut and typos - imprint, shape) - a typical set of morphological types of chromosomes for a species (shape, size, structural details, number, etc.). An important underlying genetic characteristic of a species. To determine the karyotype, a microphotograph of the chromosomes of dividing cells is used.

Mesoderm- the middle germ layer in most multicellular animals and humans. From it the organs of blood and lymph formation, excretory organs, genitals, muscles, cartilage, bones, etc. develop.

Multipotency- the ability to differentiate within one germ layer.

Pluripotency- the ability to differentiate different tissues of different germ layers.

Multipotency- the ability of the genome of adult stem cells to change the differentiation profile when transplanted into a new recipient tissue.

Stroma(from the Greek stroma - litter) - the main supporting structure of organs, tissues and cells of living organisms and plants.

Stromal cells- cells of the connective tissue supporting structure of the organ.

Telomeres- specialized DNA-protein structures that are located at the ends of linear chromosomes of eukaryotes.

Telomerase activity- the activity of telomerase, an enzyme that, using a special mechanism, synthesizes telomeric DNA, and thereby affects cell growth. High telomerase activity is characteristic of germ cells and stem cells. As stem cells begin to differentiate, telomerase activity decreases and their telomeres begin to shorten.

Teratoma(from Greek teratos - freak) - benign tumor caused by a disorder of embryonic development. As a rule, it consists of muscle, nervous and other tissues.

Totipotency- the ability to create a whole organism, repeat embryogenesis from one cell.

Fibroblasts(from Latin fibra - fiber and blastus - sprout) - the main cellular form of connective tissue in animals and humans. Fibroblasts form the fibers and ground substance of this tissue. When the skin is injured, they participate in the closure of wounds and the formation of scars.

Ectoderm- the outer germ layer of multicellular animals. The ectoderm forms the skin epithelium, nervous system, sensory organs, anterior and posterior intestines, etc.

Endoderm- internal germ layer of multicellular animals. The intestinal epithelium and associated glands are formed from the endoderm: pancreas, liver, lungs, etc.

Thank you

Stem cells are currently a topic of very lively discussion in society. There is probably not a single person who has not at least heard the term “stem cells”. Unfortunately, apart from knowing this term, a person, as a rule, cannot say anything about what stem cells are, what their properties are, how they are obtained and why they can be used to treat a number of diseases.

This situation has arisen because numerous television programs, forums and advertisements do not provide detailed and comprehensive information about the subject. Most often, information about stem cells is presented either like an advertising video, praising them and elevating them to the role of a panacea for all diseases, or in programs they talk about scandals that, sometimes in incredible ways, are associated with the same stem cells.

That is, the situation with stem cells is similar to some circulating rumors about something mysterious, but very powerful, which can bring great good or no less terrible evil. Of course, this is wrong, and only reflects complete absence objective and comprehensive information from people. Let's consider what stem cells are, why they are needed, how they are obtained, what properties they have, and other issues that are one way or another related to these biological objects.

What are stem cells?

However, this definition of stem cells is very general, since it reflects only the main characteristic feature of this type cells, in addition to which there are many other properties that determine their varieties. In order to navigate the issue of stem cells and have a relatively complete understanding of them, it is necessary to know these characteristic properties and varieties.

Properties and types of stem cells

Potency

Due to such restrictions on potency, the following types of stem cells have been isolated:

• Totipotent - capable of turning into cells of all organs and tissues without exception;
• Polypotent (multipotent) - capable of turning into cells of several types of organs or tissues that have a common embryonic origin;
• Monopotent - capable of transforming only into varieties of cells of any one organ.

Totipotent or embryonic stem cells

Currently, totipotent stem cells are obtained only in laboratory conditions, by fertilizing an egg with a sperm and growing the embryo to the desired size. Embryonic totipotent cells are used mainly for animal experiments and for growing artificial organs.

Pluripotent stem cells

Mesenchymal stem cells

Neural stem cells

Hematopoietic stem cells

Currently, pluripotent stem cells are used in practical medicine quite often, both for the purpose of treating severe diseases (for example, diabetes mellitus, multiple sclerosis, Alzheimer's disease, etc.) and rejuvenation. Pluripotent stem cells are obtained from the organs of aborted embryos no older than 22 weeks of gestation. In this case, stem cells are divided depending on the organ from which they are obtained, for example, liver, brain, blood, etc. The cells of the fetal (embryonic) liver are most often used, since they have the most universal potency necessary for the treatment of diseases of various organs, for example, liver cirrhosis, myocardial infarction, etc. Multipotent stem cells obtained from embryonic organs are also often called fetal stem cells. This name is derived from the word "fetus", which in Latin means fetus, embryo.

Monopotent stem cells

A child is born with precisely these monopotent stem cells, which are present in every organ and tissue without exception, constituting a kind of reserve. From this reserve, new cells of each organ and tissue are formed throughout life to replace damaged and dead ones. Throughout life, such stem cells are gradually consumed, but even by the time a person dies from old age, they are still present in all organs and tissues.

This means that theoretically, only monopotent stem cells can be obtained from the organs and tissues of a child or adult. Such cells are usually named after the organ from which they were obtained, for example, nerve, liver, stomach, fat, bone, etc. However, in the bone marrow of even an adult there are two types of pluripotent stem cells - blood and mesenchymal, which are now quite easy to obtain using routine laboratory techniques. For the treatment of various diseases and rejuvenation, these blood and mesenchymal pluripotent stem cells obtained from bone marrow are most often used.

Proliferation and differentiation of stem cells

Proliferation is the ability of a cell to divide, that is, to multiply. The fact is that each stem cell, in the process of transformation into specialized cellular structures of any organs and tissues, not only undergoes a maturation process, but also divides several times. Moreover, division occurs at each successive stage of maturation. That is, from one stem cell, from several to several hundred ready-made mature cells of any organ or tissue are obtained.

Differentiation is the degree of narrow specialization of a cell, that is, the presence of a strictly defined function for which they are created. For example, highly specialized cells of the heart muscle (cardiomyocytes) are created only to perform contractions, with the help of which blood is pushed out and circulated throughout the body. Accordingly, cells that have their own specialized functions are called highly differentiated. And relatively universal cells that do not have specific functions are poorly differentiated. Normally, in the human body, all cells of organs and tissues are highly differentiated, and only monopotent stem cells are considered low-differentiated. These cells do not have specific functions and are therefore poorly differentiated.

The process of transforming a stem cell into a specialized one with clear and defined functions is called differentiation, during which it turns from low-differentiated to highly differentiated. During the process of differentiation, a stem cell goes through numerous stages, at each of which it divides. Accordingly, the lower the differentiation of a stem cell, the more stages it will have to go through in the process of differentiation, and the more times it will divide.

Based on this, the following simple rule can be formulated: the higher the potency of the cell, that is, the lower the degree of differentiation, the stronger its ability to proliferate. This means that the most poorly differentiated totipotent stem cells have the greatest ability to proliferate. And therefore, from one totipotent stem cell, several thousand specialized and highly differentiated cells of various organs and tissues are formed. And the most highly differentiated monopotent stem cells have minimal ability to proliferate. Therefore, from one monopotent cell only a few highly differentiated cells of any organ or tissue are formed.

Types of stem cells in various organs

Brain stem cells

Brain stem cells are classified as pluripotent nerve cells, that is, they can form and form any cellular structure of the nervous system of any organ or tissue. For example, brain stem cells can form neurons of the convolutions, structures of the spinal cord, nerve fibers, sensory and motor receptors, cardiac conduction system, etc. In general, any nerve cell in any part of the human body can form from a brain pluripotent stem cell.

This type of cell is commonly used to treat neurodegenerative diseases and traumatic injuries nerves, such as strokes, multiple sclerosis, Alzheimer's disease, tissue crushing, paresis, paralysis, cerebral palsy, etc.

Liver stem cells

Two types of pluripotent stem cells are obtained from the liver of fetuses - hematopoietic and mesenchymal. At the first stage, a mixture of both types of pluripotent stem cells is obtained, and then, if necessary, they are separated. Mesenchymal fetal cells are of the greatest value, since they can be used to grow full-fledged and functionally active cells of various types. internal organs, such as lungs, heart, liver, spleen, kidneys, uterus, bladder, stomach, etc. Currently, cells of almost all organs are successfully grown in test tubes by adding special substances to the nutrient medium that force them to differentiate in a given direction. For example, to grow a cardiomyocyte (heart cell), 5-azacytidine is added to the nutrient medium, and to obtain all the rest specialized types organ cells - others are needed chemical substances. Moreover, in order to form a cell for each specific organ, it is necessary to add a strictly defined compound to the nutrient media.

Fetal liver stem cells are used to treat various severe, chronic diseases of internal organs, such as cirrhosis, heart attacks, urinary incontinence, pulmonary tuberculosis, diabetes etc.

Stem cells from umbilical cord blood

Hematopoietic cells can transform into any cellular blood elements (platelets, leukocytes, erythrocytes, monocytes and lymphocytes) and promote the growth of blood vessels. A small percentage of hematopoietic stem cells can develop into blood and lymph vessel cells.

Currently, umbilical cord blood stem cells are most often used for rejuvenation or treatment of various severe, chronic diseases. In addition, many women decide to collect cord blood and isolate stem cells for further storage in a cryobank, so that they can use the finished material if necessary.

Most commonly used classification of stem cells

• Embryonic stem cells (have totipotency and are obtained from artificially fertilized eggs grown in test tubes until the required period);
• Fetal stem cells (possess multipotency and are obtained from abortive material);
• Adult stem cells (have multipotency and are obtained from umbilical cord blood or bone marrow of an adult or child).

• Hematopoietic stem cells (are the precursors of absolutely all vascular blood cells);
• Mesenchymal stem cells (are the precursors of all cells of internal organs and skeletal muscles);
• Connective tissue stem cells (are the precursors of skin cells, bones, fat, cartilage, ligaments, joints and blood vessels);
• Neurogenic stem cells (are the precursors of absolutely all cells related to the nervous system).

Obtaining stem cells

• Umbilical cord blood of a newborn baby;
• Bone marrow of a child or adult;
• Peripheral blood (from a vein) after special stimulation;
• Abortive material obtained from women at 2–12 weeks of pregnancy;
• Fetuses between 18 and 22 weeks of pregnancy who died as a result of premature birth, late miscarriage or abortion for social reasons;
• Tissues of recently deceased healthy people (for example, death occurred as a result of injury, etc.);
• Adipose tissue of an adult or child;
• Fertilization of an egg in vitro by a sperm to form a zygote.

Stem cells are obtained from umbilical cord and peripheral blood, as well as bone marrow, using the same methods. To obtain them, firstly, bone marrow is taken (from 20 to 200 ml) during puncture ilium in adults or the sternum in children. Peripheral blood is withdrawn from a vein in the same way as for a transfusion. And umbilical cord blood is simply collected into a sterile tube right in the maternity hospital, placing it under the baby’s cut umbilical cord.

The blood or bone marrow is then transported to the laboratory, where stem cells are isolated from them in one of two ways: possible methods. Ficoll-urografin density gradient separation is most often used. To do this, pour a layer of Ficoll into a test tube, then carefully pour urografin on top of it so that the solutions do not mix. And finally, blood or bone marrow is also carefully layered onto the surface of the urografin, trying to ensure that it is minimally mixed with the two previous solutions. The tube is then unscrewed in a centrifuge high speed at least 8,000 rpm, as a result of which a thin ring of stem cells is compacted and concentrated at the interface between the Ficoll and urografin phases. This ring is carefully collected with a pipette into another sterile tube. Then a nutrient medium is poured into it and spun several more times in a centrifuge to remove all non-stem cells that accidentally get into the ring. Ready stem cells are either placed in a nutrient medium for further growth (cultivation), or frozen in liquid nitrogen for long-term storage, or diluted in a physiological solution and injected into a person undergoing cell therapy.

A second, less common method for obtaining stem cells is to treat blood or bone marrow with a lysis buffer. Lysis buffer is a special solution with strictly selected concentrations of salts that cause the death of all cells except stem cells. To isolate stem cells, blood or bone marrow is mixed with lysis buffer and left for 15 to 30 minutes, after which it is spun off in a centrifuge. The ball collected at the bottom of the test tube is the stem cells. All the liquid above the ball of cells is drained, the nutrient medium is poured into the test tube and unscrewed several more times in a centrifuge to remove all unnecessary cells that accidentally enter. Ready-made stem cells are used in the same way as those obtained by ficoll-urografin density gradient separation.

Obtaining stem cells from abortion material, tissue from deceased people, or fat from living adults or children is a more labor-intensive procedure that is used only by well-equipped laboratories or scientific institutions. During the isolation of cells, the material is processed with special enzymes that destroy the integrity of the tissues and turn them into one amorphous mass. This mass is treated in parts with lysis buffer and then stem cells are isolated in the same way as from blood or bone marrow.

It is as easy to obtain stem cells from fetuses between 18 and 22 weeks of pregnancy as from blood or bone marrow. The fact is that stem cells in this case are not obtained from the entire fetus, but only from the liver, spleen or brain. Organ tissues are crushed mechanically and then dissolved in physiological solution or nutrient medium. Stem cells are then obtained either using lysis buffer or ficoll-urografin density gradient separation.

Obtaining stem cells by fertilizing an egg is used only in scientific institutions. This method is available only to highly qualified scientists - cell biologists. This is usually how embryonic stem cells are obtained for experimental research. And eggs and sperm are taken from healthy women and men who agree to become donors. For such donation, scientific institutions pay a very significant reward - at least 3 - 4 thousand dollars for a portion of a man’s sperm and several eggs from a woman, which can be collected during one ovarian puncture.

Growing stem cells

During cultivation, the number of stem cells gradually increases, as a result of which every 3 weeks the contents of one bottle with a nutrient medium are divided into 2 or 3. Such cultivation of stem cells can be carried out for as long as desired, if there is necessary equipment and nutrient media. However, in practice, stem cells cannot be multiplied to a large number, since very often they become infected with various pathogenic microbes that accidentally enter the air of the laboratory room. Such infected stem cells can no longer be used or cultivated and are simply thrown away.

It should be remembered that growing stem cells is just an increase in their number. It is impossible to grow stem cells from non-stem cells.

Typically, stem cells are cultured until their number is sufficient to perform a therapeutic injection or experiment. Cells can also be cultured in liquid nitrogen before freezing to ensure a larger supply.

Separately, it is worth mentioning the special cultivation of stem cells, when various compounds are added to the nutrient medium that promote differentiation into certain type cells, for example, cardiomyocytes or hepatocytes, etc.

Use of stem cells

The use of stem cells to treat various diseases is carried out in limited clinical trials, where the patient is offered this option and explained what benefits and risks this may entail. Typically, stem cells are used only for the treatment of severe, chronic and incurable diseases by other methods, when there is practically no chance of survival and even a slight improvement in the condition. Through such clinical trials, doctors are able to see what the effects of stem cells are and what side effects may cause their use. Based on observational results, the safest and most effective clinical protocols, which prescribe the recommended dosages of stem cells (total quantity administered in pieces), places and methods of administration, as well as the optimal timing of therapy and expected effects.

For the purpose of rejuvenation, stem cells can be injected into subcutaneous tissue or into skin structures, as well as intravenously. This use of stem cells makes it possible to reduce the visible signs of age-related changes for a certain period of time. To maintain a long-term effect, stem cells will have to be administered periodically at individually selected intervals. In principle, this manipulation, when performed correctly, is safe.

Stem cell treatment of various diseases - general principles and effects

In addition, stem cells from the bone marrow of a donor, which is usually blood relatives, are often used. In this case, to eliminate the risk of rejection, before introducing cells, they are cultured in a nutrient medium for at least 21 days. Such long-term cultivation leads to the loss of individual antigens, and the cells will no longer cause a rejection reaction.

Liver stem cells are used less frequently because they must be purchased. More often this type cells are used for rejuvenation.

Ready-made stem cells are introduced into the body in various ways. Moreover, the introduction of stem cells is called transplantation, which is performed in various ways depending on the disease. Thus, in Alzheimer's disease, stem cells are transplanted into the cerebrospinal fluid using a lumbar puncture. For diseases of internal organs, cells are transplanted in the following main ways:

• Intravenous injection of stem cells diluted in a sterile saline solution;
• Introduction of stem cells into the vessels of the affected organ using special equipment;
• Injection of stem cells directly into the affected organ during surgery;
• Injection of stem cells intramuscularly in close proximity to the affected organ;
• Injection of stem cells subcutaneously or intradermally.

Cell therapy (stem cell treatment) in all cases leads to an improvement in a person’s condition, partially restores lost functions, improves the quality of life, and reduces the rate of disease progression and complications.

However, it should be remembered that stem cell treatment is not a panacea; it cannot heal completely or cancel traditional therapy. At the present stage of scientific development, stem cells can only be used as a complement to traditional therapy. Someday it may be possible to develop treatments using stem cells alone, but for now this is a dream. Therefore, when deciding to use stem cells, remember that you cannot cancel all other therapy for a severe chronic disease. Cell transplantation will only improve the condition and increase the effectiveness of traditional therapy.

Stem cell treatment: main problems - video

Stem cells: history of discovery, types, role in the body, production and treatment features - video

Stem cell bank

Currently, in almost all major cities There are similar banks in Russia that offer their services to individuals and legal entities.

Undifferentiated stem cells, which are actively used in medicine, represent the basis for the development of cells in the brain, blood, or any other organ. In modern pharmacology and cosmetology, this biological material is valuable medicine. Experts have learned to independently grow it for various needs: for example, to take umbilical cord blood material, which is widely used for restoration and strengthening immune system.

What are stem cells

To explain it in clear language, STs (undifferentiated stem cells) are the “progenitors” of ordinary cells, of which there are hundreds of thousands of species. Ordinary cells are responsible for our health, ensure the proper functioning of vital systems, make our heart beat and brain work, they are responsible for digestion, the beauty of skin and hair.

Where are stem cells found?

Despite the impressive figure of 50 billion pieces, an adult has such valuable material in very small quantities. The bulk of the cells are contained in the bone marrow (mesenchymal cells and stromal cells) and subcutaneous fat, the rest are evenly distributed throughout the body.

The embryo is formed differently. Billions of stem cells are formed after the division of the zygote, which is the result of the fusion of male and female gametes. The zygote stores not only genetic information, but also a plan for sequential development. However, during the process of embryogenesis it the only function is division. There are no other tasks other than passing on genetic memory to the next generation. The division cells of the zygote are stem cells, or more precisely, embryonic cells.

Properties

Adult cells remain dormant until one of the regulatory systems gives a danger signal. CTs are activated and travel through the bloodstream to the affected area, where, reading information from “neighbors”, they are transformed into bone, liver, muscle, nerve and other components, stimulating the body’s internal reserves for tissue restoration.

The amount of miracle material decreases with age, and the reduction begins at a very young age - 20 years. By the age of 70, very few cells remain; this tiny remnant supports the functioning of the body’s life support systems. In addition, “aged” STs partially lose their versatility; they can no longer transform into any type of tissue. For example, the possibility of transformation into nerve and blood components disappears.

Due to the lack of hematopoietic components responsible for blood formation, a person in old age becomes covered with wrinkles and dries out due to the fact that the skin no longer receives adequate nutrition. Embryonic material is the most capable of transformation, which means it is the most valuable. Such CT can degenerate into any type of tissue in the body, quickly restore immunity, and stimulate the organ to regenerate.

Varieties

It may seem that there are only two types of stem cells: embryonic and cells found in the body of a born person. But that's not true. They are classified according to pluripotency (the ability to transform into other types of tissue):

• totipotent cells;
• pluripotent;
• multipotent.

Thanks to the latter type, as the name suggests, it is possible to obtain any tissue in the human body. This is not the only classification. The next difference will be in the method of obtaining:

• embryonic;
• fetal;
• postnatal.

Fetal STs are taken from embryos that are several days old. Fetal cells are biological material collected from the tissues of embryos after abortions. Their potency is slightly lower compared to three-day embryos. Postnatal species is a biomaterial born person, obtained, for example, from umbilical cord blood.

Growing stem cells

Studying the properties of embryonic stem cells, scientists came to the conclusion that this is an ideal material for transplantation, since it can replace any tissue in the human body. Fetal components are obtained from unused tissue from embryos that are initially grown for artificial insemination. However, the use of embryos raises ethical objections, as a result, scientists have discovered a new type of stem cells - induced pluripotent.

Induced pluripotent cells (iPS) have alleviated ethical concerns without losing the unique properties that embryonic ones possess. The material for their cultivation is not embryos, but mature differentiated cells of the patient, which are removed from the body, and after work in a special nutrient medium, they are returned back, but with updated qualities.

Application

The use of ST is very wide. It is difficult to determine the areas where they are used. Most scientists say that treatment with donor biomaterial is the future, however additional research should continue to be carried out. At the moment, such work is mostly successful; it has had a positive impact on the treatment of many diseases. Take, for example, assistance in the treatment of cancer, the first stages of which have already given hope for recovery to many patients.

In medicine

It is no coincidence that medicine places great hopes on microtechnology. For 20 years, doctors from all over the world have been using bone marrow mesenchymal cells to treat serious diseases, including malignant tumors. A close relative of the patient who has a suitable blood type can become a donor of such material with an antigen kit. Scientists are also conducting other research in the field of treatment of diseases such as liver cirrhosis, hepatitis, kidney pathologies, diabetes, myocardial infarction, arthrosis of the joints, autoimmune diseases.

Treatment of various diseases with stem cells

The range of uses in treatment is amazing. Many medicines are made from CT, but transplants are particularly advantageous. Not all transplants end well due to individual rejection of the material, but treatment is successful in most cases. It is used against such ailments:

• acute leukemia (acute lymphoblastic, acute myeloblastic, acute undifferentiated and other types of acute leukemia);
• chronic leukemia (chronic myeloid, chronic lymphocytic and other types of chronic leukemia);
• pathologies of myeloid lineage proliferation (acute myelofibrosis, polycythemia vera, idiopathic myelofibrosis and others);
• phagocytic dysfunctions;
• hereditary disorders metabolism (Harler's disease, Krabbe's disease, metachromic leukodystrophy and others);
• hereditary disorders of the immune system (lymphocyte adhesion deficiency, Kostmann's disease and others);
• lymphoproliferative disorders (lymphogranulomatosis, non-Hodgkin lymphoma);
• other hereditary disorders.

In cosmetology

Methods of using stem cells have found their application in the field of beauty. Cosmetology companies are increasingly producing products with a biological component, which can be either animal or human. In cosmetics it is labeled as Stem Cells. It is credited with miraculous properties: rejuvenation, whitening, regeneration, restoration of firmness and elasticity. Some salons even offer stem cell injections, but injecting the drug under the skin will be expensive.

When choosing this or that remedy, do not be fooled by beautiful sayings. This biomaterial has nothing to do with antioxidants, and it will not be possible to achieve ten years of rejuvenation in one week. Please note that such creams and serums will not cost a penny, because obtaining stem cells is a difficult and time-consuming process. For example, Japanese scientists are trying to get snails to secrete more mucus containing the coveted material in laboratories. Soon this mucus will become the basis of new cosmetics.

Video: Stem cell

Stem cells: myths and reality

“No area of ​​biology at its birth was surrounded by such a network of prejudices, hostility and misinterpretations as stem cells,” says corresponding member of the Russian Academy of Medical Sciences, specialist in the field of medical cell biology Vadim Sergeevich Repin (Moscow Center for Biomedical Technologies).

Although the term “stem cell” was introduced into biology back in 1908, this area of ​​cellular biology received the status of big science in the last decade of the twentieth century. In 1999, Science magazine recognized the discovery of stem cells as the third most important event in biology after deciphering the double helix of DNA and the Human Genome Program. One of the discoverers of the DNA structure, James Watson, commenting on the discovery of stem cells, noted that the structure of a stem cell is unique, since under the influence of external instructions it can turn into an embryo or into a line of specialized somatic cells.

Indeed, stem cells are the progenitors of all types of cells in the body without exception. They are capable of self-renewal and, most importantly, during the process of division they form specialized cells of various tissues. Thus, all cells in our body arise from stem cells.

Stem cells renew and replace cells lost as a result of any damage in all organs and tissues. They are designed to restore and regenerate the human body from the moment of its birth. The potential of stem cells is just beginning to be harnessed by science. Scientists hope in the near future to create from them tissues and entire organs that patients need for transplantation instead of donor organs. Their advantage is that they can be grown from the patient's own cells, and they will not cause rejection.

The medical needs for such material are practically unlimited. Only 10-20 percent of people are cured due to a successful organ transplant. 70-80 percent of patients die without treatment while on the surgery waiting list. Thus, stem cells, in a sense, can really become “spare parts” for our body. But for this it is not at all necessary to grow artificial embryos - stem cells are contained in the body of any adult.

Where do stem cells come from?

Based on their origin, stem cells are divided into embryonic, fetal, umbilical cord blood stem cells and adult stem cells.

The source of embryonic stem cells is the blastocyst, an embryo that is formed by the fifth day of fertilization. These stem cells are capable of differentiating into absolutely all types of cells in the adult body. But there are drawbacks to this source of stem cells. First, these cells are capable of spontaneously degenerating into cancer cells. Secondly, the world has not yet isolated a safe line of truly embryonic stem cells suitable for clinical use.

Fetal stem cells are obtained from abortion material at 9-12 weeks of pregnancy. In addition to ethical and legal tensions, the use of untested abortifacient material is fraught with complications, such as infecting the patient with the herpes virus, viral hepatitis and even AIDS. If the material is diagnosed for viruses, the cost of the method increases, which ultimately leads to an increase in the cost of the treatment itself, which in certain cases can be very effective.

Placental cord blood collected after the birth of a child is also a source of stem cells. This blood is very rich in stem cells. By taking this blood and placing it in a cryobank of stem cells, it can later be used to restore almost any tissue and organs, as well as to treat any diseases, including cancer. However, the number of stem cells in umbilical cord blood is not large enough, and their effective use is possible only once for a child under 10 years of age.

The most accessible source stem cells is human bone marrow, since the concentration of stem cells in it is maximum. There are two types of stem cells in the bone marrow: the first is hematopoietic stem cells, from which absolutely all blood cells are formed, the second is mesenchymal stem cells, which regenerate almost all organs and tissues.

Why are stem cells needed?

If a person has his own stem cells, then why don’t the organs themselves regenerate after damage? The reason is that as a person grows up, there is a catastrophic decrease in the number of stem cells: at birth - 1 stem cell is found in 10 thousand, by the age of 20 - 25 - 1 in 100 thousand, by 30 - 1 in 300 thousand. By the age of 50, only 1 stem cell per 500 thousand remains in the body, and it is at this age that diseases such as atherosclerosis, angina, hypertension, etc. usually appear. Depletion of the supply of stem cells due to aging or severe diseases, as well as disruption of the mechanism of their release into the blood, deprives the body of the ability to effectively regenerate, as a result of which the vital activity of certain organs is depleted.

An increase in the number of stem cells in the body leads to intensive regeneration and restoration of damaged tissues and diseased organs due to the formation of young, healthy cells in place of the lost ones. Modern medicine already has such technology - it is called cell therapy.

What is cell therapy

The human body develops until the age of 25, after which the aging process begins, when every day a person notices not the most pleasant changes in his body. Age-related changes in the skin, changes in the activity of the endocrine and gonads, muscle tissue, immune and nervous systems are also associated with depletion of stem cells. Cell therapy is needed to compensate for this reserve. Healthy people There is no need to start maintenance therapy before age 35. On the contrary, everyone who suffered serious illnesses, injuries, burns or poisoning procedures are indicated at any age.

Russian science and medicine have one of the best potentials in the field of research and application of cell therapy in the world. The first targeted searches in the field of human bone marrow stem cells began as a result of a methodological breakthrough carried out by Alexander Yakovlevich Friedenstein in the mid-70s of the twentieth century. In his laboratory, a homogeneous culture of bone marrow stem cells was first obtained. After the cessation of division, stem cells, under the influence of cultivation conditions, turned into bone, fat, cartilage, muscle or connective tissue. The pioneering developments of A.Ya. Friedenstein have earned international recognition.

Now, with the help of therapeutic stem cell transplantation, it is possible to treat or use as accompanying therapy a whole range of diseases - diabetes mellitus, atherosclerosis, ischemic disease hearts, chronic diseases joints, chronic injuries, hepatitis and cirrhosis of the liver, autoimmune diseases, Alzheimer's and Parkinson's diseases, chronic fatigue syndrome.

With the help of cell therapy, burns, wounds, ulcers and skin scars quickly heal, rehabilitation after strokes and traumatic brain injuries is carried out, a comprehensive regeneration program is carried out (improving the functional abilities of the body and quality of life) and mesotherapy of the face, hands, problem (flabby) areas and of the whole body. Cell therapy is used as maintenance therapy for multiple sclerosis, sexual pathologies and infertility in men and women, cancer.

Of course, the use of stem cells is not a panacea. Thus, their use in oncology does not lead to a cure for cancer. However, there are a number of unique programs aimed at the rehabilitation of patients during remission and breaks between chemotherapy courses. Patients receiving this course tolerate all procedures much better, the number of complications decreases, and it becomes possible to repeat procedures earlier. Thus, the chances of success increase significantly. In addition, stem cells also have a proven anti-cancer effect: they inhibit tumor development and activate the immune system.

How is cell therapy performed?

After the examination and collection of tests, the patient is offered to donate blood (bone marrow), in which a certain amount of stem cells is constantly present. Modern technologies make it possible to isolate stem cells, and then grow these cells in a special environment in much larger quantities. At the end of the cultivation process, the patient is prescribed an individual course of introducing native cellular material. All treatment takes place on an outpatient basis and does not require changes to the usual rhythm of life.

To collect your own cellular material, a bone marrow puncture is necessary. Preparation for the procedure, the bone marrow collection procedure itself and rest after it last 1.5 hours (the procedure itself takes no more than 20 minutes), after which the patient needs to come to the doctor after 7 days for the initial injection and then visit him for subsequent injections according to the drawn up graphics.

The introduction of cellular material is a painless procedure performed on an outpatient basis under sterile conditions. Cellular material can be administered intravenously, intramuscularly, intraarticularly, subcutaneously, and also in the form of applications, depending on the method of treatment and the nature of the disease.

The average duration of the course (depending on the chosen program) is 2.5-3 months. Apart from the initial stage, the patient does not need to visit the doctor more than 1-2 times a week throughout the entire course.

As a rule, half of all patients are interested in a comprehensive program of body regeneration. The other half of patients are sick different ages, with various diseases and their complications - after serious injuries, accidents, strokes, burns, after operations, stress, cardiac complications.

Cell therapy is the future modern medicine, this direction is intensively developing all over the world. It is pleasant that our country not only does not lag behind other countries in this area, but is ahead of them in some ways.

Modern medical technologies of the 21st century can do things that our ancestors could not even dream of. For example, it is possible to 3D print a part of an intervertebral disc implant or make a fragment from special plastic that fits the patient perfectly. But our own body already contains all the necessary information about every substance and every structure that once existed in it. This information is encoded in genes and chromosomes, which are stored in the nucleus of a somatic cell. But a person is designed in such a way that it is impossible to “pull” her out of there at the right moment. The core of the cell is not at all like the storage of drawings on a factory assembly line. Only body stem cells can start this process. Most of them were active during human intrauterine development. After all, an embryo is capable of turning into an adult by simple division in half, and this continues for some time before specialization begins.

Stem cells newborn are contained in such invaluable material as umbilical cord blood. Extracted from there, in terms of activity and ability to specialize, they are far ahead of everything that is in the body of adults. In addition, a small “reserve” is located in the pulp of fallen milk teeth. Stem cells in teeth– this is the last gift from nature for the baby to restore his own tissues.

Then, as the organism forms, stem cells lose their “fuse” and become necessary only where there is a constant production of new cells in a very large volume. These newest stem cells are engaged in constant blood renewal. Blood is a unique, highly specialized tissue and is produced in the red bone marrow.

Brain stem cells are the only ones active in the human body that has developed and become an adult. Moreover, these structures remain active and do not reduce their “fertility” until the person’s death, producing colossal offspring.

It can be said that brain stem cells are immortal, but at the same time they do not simply reproduce copies of themselves, but are capable of specialization. Depending on the need and the necessary biochemical stimuli, they are able to turn into red blood cells, leukocytes of all types, and platelets.

The most important are pluripotent stem cells. Their population is maintained at low numbers. Then, accumulating and dividing in very large quantities, they gradually acquire the necessary specialization, turning into fully functional blood cells.

But such “narrow specialization” led to the fact that brain stem cells(red bone) with great difficulty can “remember” the past, and turn into, say, neurons or myocardiocytes. As a result, the possibilities of their transplantation are largely limited.

As sad as it may be, in addition to red bone marrow, you can take stem cells out of nowhere. Nature abhors a vacuum, and these structures are found only where new cells are intensively formed. Any anabolic processes: wound healing, maturation of eggs in the ovary in women and spermatogenesis in men are far behind hematopoiesis.

That is why, if necessary, when required stem cell transplant, for this purpose they use or their own stem cells from blood, or similar materials are taken from relatives. Certainly, stem cell transplant relatives has less chance of success. Imagine that a cat has torn off the wallpaper in your home and you need to change a small piece. You don’t have original leftovers, but in the store they offer you very similar ones, but still not the same. The same is true with stem cell transplant relatives, only instead of aesthetic discomfort, one should be wary of a greater number of complications and less clinical effect.

But an invaluable source of much “stronger” cells is cord blood And stem cells in teeth(dairy).

What to do? Use your own if necessary brain stem cells, although we hope that this moment never comes. But we have the power to protect the younger generations and preserve the health of unborn babies. To do this, you just need to organize during childbirth cord blood collection, which is placed in a special stem cell bank and is stored there at liquid nitrogen temperature until needed.

If this moment is missed, then you can get stem cells from your babies' milk teeth and send them for long-term storage. Baby Teeth Stem Cell Bank and umbilical cord blood is a European invention. Stem cell bank in Europe(one of the best) is located in France, as well as in the Principality of Monaco. Cofrance SARL, which works with Europe's leading biological stem cell bank, will help you take a step in the right direction.

You can find out more on the company’s website, since the company has a service for servicing Russian-speaking clients. After all, alternatives to preserve the health and life of your children and grandchildren in Russia with the help cell technologies not yet and not expected.