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Stem cells and their properties. Cord blood cells

1908: term " stem cell"(Stammzelle) was proposed for widespread use by the Russian histologist Alexander Maximov (1874-1928). He described and proved hematopoietic stem cells using the methods of his time, and it was for them that the term was introduced.
1960s: Joseph Altman and Gopal D. Das () presented scientific evidence of adult neurogenesis, the constant activity of brain stem cells. Their findings contradicted Ramón y Cajal's dogma that nerve cells are not born into an adult body, and have not received wide publicity.
1963: Ernest McCulloch and James Till demonstrated the presence of self-renewing cells in mouse bone marrow.
1968: the possibility of restoring hematopoiesis in the recipient after transplantation was proven bone marrow. Bone marrow transplantation in eight-year-old boy results in cure for severe form immunodeficiency. The donor was a sister with a compatible set of leukocyte antigens (HLA).
1970: Alexander Yakovlevich Friedenstein isolated fibroblast-like cells from the bone marrow of guinea pigs, successfully cultivated and described them, which were subsequently named Multipotent mesenchymal stromal cells.
1978: Hematopoietic stem cells are discovered in umbilical cord blood.
1981: Mouse embryonic cells are obtained from the embryoblast (the inner cell mass of the blastocyst) by scientists Martin Evans, Matthew Kaufman and, independently, Gail R. Martin. Gail Martin is credited with coining the term embryonic stem cell.
1988: Eliane Gluckman performed the first successful cord blood HSC transplantation in a patient with Fanconi anemia. E. Gluckman has proven that the use of cord blood is effective and safe. Since then, cord blood has been widely used in transplantology.
1992: neural stem cells obtained in vitro. Protocols for their cultivation in the form of neurospheres have been developed.
1992: first personalized stem cell collection. Professor David Harris froze the umbilical cord blood stem cells of his first child. Today, David Harris is the director of the world's largest umbilical cord blood stem cell bank.
1987-1997: For 10 years at 45 medical centers 143 cord blood transplants have been performed worldwide.
1997: The first operation on an oncology patient to transplant umbilical cord blood stem cells was performed in Russia.
1998: James Thomson and his collaborators at the University of Wisconsin-Madison developed the first line of human ESCs.
1998: The world's first autologous cord blood stem cell transplant into a girl with neuroblastoma (brain tumor). The total number of cord blood transplantations performed this year exceeds 600.
1999: magazine Science recognized the discovery of embryonic stem cells as the third most significant event in biology after deciphering the double helix of DNA and the Human Genome Project.
2000: a number of articles were published on the plasticity of stem cells of a mature organism, that is, their ability to differentiate into the cellular components of various tissues and organs.
2003: The Journal of the National Academy of Sciences of the United States (PNAS USA) published a report that after 15 years of storage in liquid nitrogen, umbilical cord blood stem cells fully retain their biological properties. From this point on, cryogenic storage of stem cells began to be viewed as “biological insurance.” The world's collection of stem cells stored in banks has reached 72,000 samples. As of September 2003, 2,592 umbilical cord blood stem cell transplants have already been performed in the world, 1,012 of them to adult patients.
During the period from 1996 to 2004, 392 autologous (own) stem cell transplants were performed.
2005: Scientists from the University of California at Irvine injected human neural stem cells into rats with traumatic injury spinal cord, and were able to partially restore the rats’ ability to move.
2005: the list of diseases for which stem cell transplantation has been successfully used reaches several dozen. The main focus is on the treatment of malignant neoplasms, various forms leukemia and other blood diseases. There are reports of successful stem cell transplantation for diseases of the cardiovascular and nervous systems. In different research centers Research is being conducted on the use of stem cells in the treatment of myocardial infarction and heart failure. International protocols for the treatment of multiple sclerosis have been developed. Approaches to the treatment of stroke, Parkinson's and Alzheimer's diseases are being sought.
August 2006: The journal Cell publishes a study by Kazutoshi Takahashi and Shinya Yamanaka on a way to return differentiated cells to a pluripotent state. The era of induced pluripotent stem cells begins.
January 2007: Researchers from Wake Forest University (North Carolina, USA) led by Dr. Anthony Atala from Harvard reported the discovery of a new type of stem cells found in amniotic fluid (amniotic fluid). They may be a potential replacement for ESCs in research and therapy.
June 2007: Three independent research groups reported that mature mouse skin cells can be reprogrammed into ESCs. In the same month, scientist Shukhrat Mitalipov announced the creation of a primate stem cell line through therapeutic cloning.
November 2007: in the magazine Cell published a study by Katsutoshi Takagashi and Shinya Yamanaka, “Induction of pluripotent stem cells from mature human fibroblasts under certain factors,” and in the journal Science The article “Induced pluripotent stem cells derived from human somatic cells” by Juning Yu, co-authored with other scientists from James Thomson’s research group, was published. It has been proven that it is possible to induce almost any mature human cell and give it stem properties, as a result of which there is no need to destroy embryos in the laboratory, although the risks of carcinogenesis in connection with the Myc gene and retroviral gene transfer remain to be determined.
January 2008: Robert Lanza and his colleagues from Advanced Cell Technology and the University of California at San Francisco produced the first human ESCs without destroying the embryo.
January 2008: Cloned human blastocysts are cultured through therapeutic cloning.
February 2008: pluripotent stem cells derived from mouse liver and stomach, these induced cells are closer to embryonic than previously derived induced stem cells and they are not carcinogenic. In addition, the genes required to induce pluripotent cells do not need to be placed in a specific region, which facilitates the development of non-viral cell reprogramming technologies.
March 2008: a study by doctors from the Regenerative Sciences Institute was published for the first time on the successful regeneration of cartilage in the human knee joint using autologous mature MSCs.
October 2008: Zabine Konrad and her colleagues from Tübingen (Germany) derived pluripotent stem cells from spermatogonial cells of a mature human testicle by culturing in vitro with the addition of FIL (leukemia inhibition factor).
October 30, 2008: Embryonic stem cells derived from human hair.
March 1, 2009: Andreas Nagy, Keisuke Kaji and their colleagues discovered a way to develop embryonic stem cells from normal mature cells using innovative technology“wraps” to deliver specific genes into cells for the purpose of reprogramming without the risks that arise when using viruses. Genes are placed into cells using electroporation.
May 28, 2009: Kim Gwangsoo and his colleagues at Harvard announced that they had developed a way to manipulate skin cells to produce induced pluripotent stem cells in a patient-specific manner, claiming it was the “ultimate solution to the stem cell problem.”
2011: Israeli scientist Inbar Friedrich Ben-Nun led a team of scientists that developed the first stem cells from endangered animal species. This is a breakthrough and thanks to it we can save species that are in danger of extinction.
2012: Giving patients stem cells taken from their own bone marrow three to seven days after a heart attack is a safe but ineffective treatment, according to a clinical trial supported by the US National Institutes of Health. However, studies conducted by German specialists in the department of cardiology in Hamburg showed positive results in the treatment of heart failure, but not myocardial infarction.

Properties

All stem cells have two essential properties:

Self-renewal, that is, the ability to maintain an unchanged phenotype after division (without differentiation).
Potency (differentiation potential), or the ability to produce offspring in the form of specialized cell types.

Self-updating

There are two mechanisms that maintain the stem cell population in the body:

Asymmetric division, which produces the same pair of cells (one stem cell and one differentiated cell).
Stochastic division: one stem cell divides into two more specialized ones.

Differentiating potential

Differentiation potential, or potency, of stem cells is the ability to produce a certain number of different types of cells. According to potency, stem cells are divided into the following groups:

Totipotent (omnipotent) stem cells can differentiate into cells of embryonic and extraembryonic tissues, organized in three dimensions related structures(tissues, organs, organ systems, body). Such cells can give rise to a full-fledged viable organism. These include a fertilized egg, or zygote. Cells formed during the first few division cycles of the zygote are also totipotent in most species. However, these do not include, for example, roundworms, the zygote of which loses totipotency during the first division. In some organisms, differentiated cells can also acquire totipotency. Thus, the cut part of a plant can be used to grow a new organism precisely due to this property.
Pluripotent stem cells are descendants of totipotent stem cells and can give rise to almost all tissues and organs, with the exception of extraembryonic tissues (for example, the placenta). From these stem cells, three germ layers develop: ectoderm, mesoderm and endoderm.
Multipotent stem cells give rise to cells of different tissues, but the diversity of their types is limited within a single germ layer.

Oligopotent cells can differentiate only into certain cell types with similar properties. These, for example, include cells of the lymphoid and myeloid series, involved in the process of hematopoiesis.
Unipotent cells (precursor cells, blast cells) are immature cells that, strictly speaking, are no longer stem cells, since they can produce only one type of cell. They are capable of repeated self-reproduction, which makes them a long-term source of cells of one specific type and distinguishes them from non-stem cells. However, their ability to reproduce themselves is limited to a certain number of divisions, which also distinguishes them from true stem cells. Progenitor cells include, for example, some of the myosatellite cells involved in the formation of skeletal and muscle tissue.

Classification

Stem cells can be divided into three main groups depending on the source of their production: embryonic, fetal and postnatal (adult stem cells).

Embryonic stem cells

Clinical studies using ESCs are subject to special ethical review. In many countries, ESC research is restricted by law.

One of the main disadvantages of ESCs is the impossibility of using autogenous, that is, one’s own material, for transplantation, since isolating ESCs from the embryo is incompatible with its further development.

Fetal stem cells

Postnatal stem cells

Despite the fact that stem cells of a mature organism have less potency compared to embryonic and fetal stem cells, that is, they can generate fewer various types cells, the ethical aspect of their research and use does not cause serious controversy. In addition, the possibility of using autogenous material ensures the effectiveness and safety of treatment. Adult stem cells can be divided into three main groups: hematopoietic (hematopoietic), multipotent mesenchymal (stromal) and tissue-specific progenitor cells. Sometimes umbilical cord blood cells are classified into a separate group because they are the least differentiated of all the cells of a mature organism, that is, they have the greatest potency. Umbilical cord blood mainly contains hematopoietic stem cells, as well as multipotent mesenchymal cells, but it also contains others unique varieties stem cells, under certain conditions capable of differentiating into cells various organs and fabrics.

Hematopoietic stem cells

Before the use of umbilical cord blood, bone marrow was considered the main source of HSCs. This source is still widely used in transplantology today. HSCs are located in the bone marrow in adults, including the femurs, ribs, sternum, and other bones. Cells can be obtained directly from the thigh using a needle and syringe, or from the blood after pretreatment with cytokines, including G-CSF (granulocyte colony-stimulating factor), which promotes the release of cells from the bone marrow.

The second, most important and promising source of HSC is umbilical cord blood. The concentration of HSCs in cord blood is ten times higher than in bone marrow. In addition, this source has a number of advantages. The most important of them:

Age. Umbilical cord blood is collected at the earliest stage of the body's life. Umbilical cord blood HSCs are maximally active because they have not been subjected to negative impact external environment(infectious diseases, unhealthy diet, etc.). Umbilical cord blood HSCs are capable of creating a large cell population in a short period of time.
Compatibility. The use of autologous material, that is, one’s own cord blood, guarantees 100% compatibility. Compatibility with brothers and sisters is up to 25%; as a rule, it is also possible to use the child’s umbilical cord blood to treat other close relatives. For comparison, the probability of finding a suitable stem cell donor is from 1:1000 to 1:1000,000.

Multipotent mesenchymal stromal cells

Multipotent mesenchymal stromal cells (MMSCs) are multipotent stem cells capable of differentiating into osteoblasts (bone cells), chondrocytes (cartilage cells) and adipocytes (fat cells).

Characteristics of embryonic stem cells

Stem cells and cancer

Use in medicine

In Russia

By order of the Government of the Russian Federation of December 23, 2009 No. 2063-r, the Ministry of Health and Social Development of Russia, the Ministry of Industry and Trade of Russia and the Ministry of Education and Science of Russia were instructed to develop and submit for consideration to State Duma RF draft law “On the use of biomedical technologies in medical practice”, regulating medical use stem cells as one of the biomedical technologies. Since the bill caused outrage among the public and scientists, it was sent for revision and this moment not accepted.

On July 1, 2010, the Federal Service for Surveillance in Healthcare and Social Development issued the first permit for the use of new medical technology FS No. 2010/255 (treatment with one’s own stem cells).

February 3, 2011 Federal service for supervision in the field of healthcare and social development issued permission for the use of new medical technology FS No. 2011/002 (treatment of the following pathologies with donor stem cells: age-related changes in facial skin of the second or third degree, the presence of a wound skin defect, trophic ulcer, treatment of alopecia, atrophic lesion skin, including atrophic stripes (striae), burns, diabetic foot)

In Ukraine

Today, clinical trials are allowed in Ukraine (Order of the Ministry of Health of Ukraine No. 630 “On conducting clinical trials of stem cells”, 2007.

Stem cells , as well as technologies based on their use, attract great attention from scientists around the world. This is due to two reasons. Firstly, developments based on SC are truly revolutionary technologies that have changed approaches to the treatment of many serious illnesses. Secondly, thanks to not very competent publications in the media, in the mass consciousness, research on SCs is associated with cloning or “growing human embryos for spare parts.”

Debunking myths. The truth about stem cells

“At its birth, no area of biology was surrounded by such a network of prejudices, hostility and misunderstandings as stem cells,” says Vadim Sergeevich Repin, corresponding member of the Russian Academy of Medical Sciences, a specialist in the field of medical cell biology.

The term "stem cell" was introduced into biology in 1908, the status of big science this area cell biology received only in the last decade of the twentieth century.

In 1999, Science magazine recognized the discovery of stem cells (SC) 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 the stem cell, noted that the structure of a stem cell is unique, since under the influence of external instructions it can turn into a “germ” cell line, or a line of specialized somatic cells.

The truth about stem cells is this: they are the progenitors of all types of cells in our body without exception. They are capable of self-renewal and, most importantly, when dividing, they form specialized cells of various tissues. Thus, all cells in our body arise from stem cells.

SCs are capable of renewing and replacing cells lost due to damage in all organs or tissues. Their calling is to restore and regenerate the human body from the moment it is born.

The potential of stem cells is just beginning to be harnessed by science. In the near future, scientists want to create from them tissues and entire organs that patients need for transplantation instead of donor organs. They can be grown from the patient’s own cells and will not cause rejection, which is a big advantage.

The medical needs for such material are practically unlimited. Only 10-20% of people are cured thanks to a successful internal organ transplant. 70-80% of patients die without treatment, without waiting their turn for surgery.

Thus, SCs 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.

Why is stem cell research 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 older, there is a constant decrease in the number of stem cells: at birth - 1 SC occurs per 10 thousand cells, by 20 - 25 years - 1 in 100 thousand, by 30 - 1 in 300 thousand (average figures are given). By the age of 50, the body on average has only 1 SC left in 500 thousand, and it is at this age that, as a rule, diseases such as atherosclerosis, angina pectoris, hypertension, etc. already appear.

Depletion of the supply of stem cells due to aging or severe diseases, as well as disruption of the mechanism for their release into the systemic circulation, deprives the body of its capabilities. effective regeneration, after which the vital activity of certain organs weakens.

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

What is cell therapy ?

(CT) is a type of treatment that uses living cells. It can be assumed that in the near future this type of therapy will become more widespread, effective, and also safe.

The use of CT in Russia is a controversial process. There are few fundamental organizations working in this area. Basically, the use of CT in the Russian Federation is limited to a single medical technology or technique, registered by the appropriate authority, issued as a permit to the applicant clinical institution for a limited period (for example, a year). This means that the use of SC by this organization is possible only within the framework of the declared methodology, strictly for the treatment of the specified type of disease. We are talking about the use of the patient's own cell components or a blood donor. Commercial use of CT scans is permissible in this case if the necessary documentation is available.

In some research institutes, others government institutions patients may be offered treatment using cell technologies in limited clinical trials, within the boundaries of the stated technique and treatment specific disease. However, such work is rarely carried out. As a rule, treatment is usually free for a volunteer patient.

Russian science and medicine have great potential in the field of SC research and the use of cell therapy. The first targeted searches in the area therapeutic use Human bone marrow SCs began as a result of a methodological breakthrough carried out by Alexander Yakovlevich Friedenstein dating back to the mid-70s of the twentieth century. In the laboratory of Alexander Yakovlevich, for the first time in the world, a homogeneous culture of bone marrow stem cells was obtained.

After the cessation of division, under the influence of cultivation conditions, they turned into bone, fat, cartilage, muscle or connective tissue. The pioneering developments of A.Ya. Friedenstein have earned international recognition.

Since then it has become increasingly accessible and scientifically sound. With the help of therapeutic stem cell transplantation, it is possible to treat a whole range of diseases, including: diabetes, atherosclerosis, ischemic disease heart disease, chronic joint diseases, old injuries, hepatitis, liver cirrhosis, autoimmune diseases, Alzheimer's disease, Parkinson's disease, syndrome chronic fatigue. Cell therapy can be used as supportive therapy for multiple sclerosis, sexual pathologies, infertility in men and women, and cancer.

Depending on the treatment method, the cellular material can be administered intramuscularly, intravenously, subcutaneously, intraarticularly, or in the form of applications - this also depends on the nature of the disease.

Of course, the use of stem cells is not a panacea. It cannot be said that their use in oncology leads to a cure for cancer; however, modern protocols are emerging that are aimed at the rehabilitation of patients during remission and during breaks between chemotherapy courses. Experience shows that patients receiving this course are able to better tolerate the main treatment, the number of complications is noticeably reduced, and it becomes possible to repeat the chemotherapy procedure a little earlier. Thus, the chances of treatment success increase. In addition, stem cells have a proven anti-cancer effect: they inhibit tumor development and activate the immune system.

The use of CT is at the beginning of its journey. In most nosologies, the impact of stem cells on the disease itself is just beginning to be studied. Today, only in some nosologies have convincing results been obtained from the use of SC. Aspects of the clinical use of CT are outlined at the end of this article.

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I would like to remind visitors to the portal that Not has information about organizations that use for the treatment of diseases in Russia. We cannot recommend medical institutions, working in this area, and do not have information about " the best specialists" The portal administration is also unaware of institutions inviting patients to take part in clinical trials using stem cells. Please remember this. Reliable information about the quality of the proposed procedures is usually absent, and the level of qualifications of the specialists who prescribe them is not always high enough. This resource is dedicated exclusively to coverage of cellular technologies.

Where do stem cells come from?

SC can be obtained from various sources. Some of them have strictly scientific application, others are used in clinical practice today. According to their origin, they are divided into embryonic, fetal, umbilical cord blood cells and adult cells.

Embryonic stem cells

The first type of stem cells should be called cells that are formed during the first few divisions of a fertilized egg (zygote) - each can develop into an independent organism (for example, identical twins are obtained).

After a few days of embryonic development, at the blastocyst stage, embryonic stem cells (ESCs) can be isolated from its inner cell mass. They are capable of differentiating into absolutely all types of cells of an adult organism; they are capable of dividing indefinitely under certain conditions, forming the so-called “immortal lines”. But this source of SC has disadvantages. Firstly, in an adult body, 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. Cells obtained in this way (in most cases using the cultivation of animal cells) are used by world science for research and experiments.

Clinical use of such cells is impossible today.

Fetal stem cells

Very often in Russian articles, embryonic SCs are called cells obtained from aborted fetuses (fetuses). This is not true! In the scientific literature, cells obtained from fetal tissue are called fetal.

Fetal SCs are obtained from abortive material at 6-12 weeks of pregnancy. They do not have the above-described properties of ESCs obtained from blastocysts, that is, the ability for unlimited reproduction and differentiation into any type of specialized cells. Fetal cells have already begun differentiation, and, therefore, each of them, firstly, can go through only a limited number of divisions and, secondly, give rise to not just any, but quite a few certain types specialized cells. This fact makes their clinical use safer. Thus, specialized liver cells and hematopoietic cells can develop from fetal liver cells. From fetal nerve tissue, accordingly, more specialized nerve cells develop, etc.

Cell therapy as a type originates precisely from the use of fetal SCs. In the last 50 years in different countries A series of clinical studies using them have been carried out around the world.

In Russia, in addition to ethical and legal tensions, the use of untested abortifacient material is fraught with complications, such as patient infection with the herpes virus, viral hepatitis and even AIDS. The process of isolating and obtaining FGC is complex; it requires modern equipment and special knowledge.

However, with professional supervision, well-prepared fetal stem cells have huge potential V clinical medicine. Work with fetal SCs in Russia today is limited to scientific research. Their clinical use has no legal basis. Such cells are used more widely and officially today in China and some other Asian countries.

Cord blood cells

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 for storage, it can later be used to restore many organs and tissues of the patient, as well as for treatment various diseases, primarily hematological and oncological.

However, the amount of SCs in cord blood at birth is not large enough, and their effective use, as a rule, is possible only once for the child himself under the age of 12-14 years. As you grow older, the volume of harvested SCs becomes insufficient for a full clinical effect.

Adult stem cells

Stem cells remain with us throughout our lives, from birth. The most accessible source of stem cells is the bone marrow of an adult, since the concentration of stem cells in it is maximum.

A well-prepared procedure for collecting such cells is usually completely safe. Cells obtained from the patient themselves are called autologous stem cells (ASC). Their activity and quality are not much different from cells obtained from other sources. At the same time, there are no legal restrictions on their use and no ethical tensions.

Given that vocational training the use of such cells in clinical medicine is considered safe: they are not rejected, do not have oncogenic properties, and there is no risk of infection dangerous infections during transplantation.

There are two types of stem cells in the bone marrow: the first is hematopoietic SCs, from which absolutely all blood cells are formed, the second is mesenchymal SCs, which regenerate almost all organs and tissues. They can also be obtained from other sources: for example, from adipose tissue. However, the effectiveness of SCs obtained in this way, as well as the safety of their use, remains in question. Another type of stem cells that are present in almost all tissues are regional SCs - as a rule, these are already fairly differentiated cells that can give rise to only a few types of cells that make up the tissues of a given organ.

Clinical applications of stem cells

The use of adult SC in medicine today is developing on a large scale, including in Russia. With the advent of quality laboratory equipment protocols for the preparation of adult donor stem cells provide increasingly safe and effective treatments. The clinical use of other types of SCs is currently severely limited or prohibited due to the lack of a legal basis.

If the necessary conditions and permitting documentation are available, the use of ASCs in Russia is permissible: this is mainly work in the field of oncohematology (SCs are blood components), also carried out all over the world. In some cases, permission for the limited use of SC may be obtained for other nosologies. However, it should be remembered that the presence of a permitting base does not necessarily imply the presence of knowledge and experience. An organization offering such services must have a full set of modern conditions, which, at a minimum, presupposes the presence of: a clinical base, a medical team of specialists in the field of cell therapy, knowledge in the field of diagnosis and assessment of contraindications when working with SC, experience in working with the identified disease, clinical experience, laboratory capacity and research team.

Specialized institutions working with ASC, as well as experienced specialists in this area there are only a few. Specialists from such institutions know exactly the whole truth about stem cells and will not claim that their use is a panacea and that all possible diseases can be treated today. On the contrary, such specialists usually testify that clinical results were obtained only in a small list of nosologies, and the therapy itself has a number of limitations. Along with this, expertly executed cell therapy is radical view treatment, and clinical effect may surpass any analogues classical medicine. In some cases, SCs are the only means of treatment and rehabilitation of patients.

The use of cellular technologies is a very specialized, knowledge-intensive process. Sentences like “3 injections in three weeks and everything will be fine” should seriously alert any patient. Treatment must be comprehensive, its duration can be several months, and it is always carried out under the supervision of experienced specialists.

We are monitoring developments...

Stem cells are called progenitor cells, from which, if necessary, all other types of cells that make up various human organs and tissues are formed. The term “stem cell” was first introduced in 1908 by Russian hematologist from St. Petersburg A. Maksimov. A significant amount of stem cell research was carried out by biologists A. Friedenstein and I. Chertkov in Russia in the 60s of the last century. It was they who discovered mesenchymal stem cells (MSCs) in the bone marrow, which have a unique regenerative ability. The difference between embryonic and mesenchymal stem cells is that the former can be obtained at an early stage of human embryo development (from internal mass blastocyst - a fertilized egg - or from the rudiments of the genital organs at the earliest stages of development, literally in the first days), and the latter are found throughout a person’s life in all his organs and tissues. Embryonic SCs are much more active than mesenchymal SCs and have more high ability reproduction, high differentiation potential. In addition to mesenchymal SCs, hematopoietic cells are also isolated - the precursors of blood cells. They are found in the bloodstream, in contrast to mesenchymal ones, which circulate in the blood only when serious damage body.

Stem cells are capable of restoring hematopoiesis in irradiated animals (radioprotective effect), maintaining hematopoiesis for a long time and forming colony-forming units of the spleen (twelve-day splenic colonies), giving rise to granulocytic, monocyte, erythroid, megakaryocyte and lymphoid colonies. All cells of hematopoietic origin are formed from primitive hematopoietic stem cells (pHSC), localized in the bone marrow and giving rise to cells of four main directions of differentiation:

erythroid (red blood cells),

megakaryocyte (platelets),

myeloid (granulocytes and mononuclear phagocytes)

lymphoid (lymphocytes).

Divergence of the common stem element occurs at the earliest stage of bone marrow differentiation.

Antigen-presenting cells primarily, but not exclusively, develop from myeloid progenitor cells.

Myeloid and lymphoid cells are most important for function immune system.

The lymphopoietic stem cell determines two independent lines of development, leading to the formation of T cells and B cells.

The first progenitor cell formed from HSCs is a colony-forming unit (CFU), which determines the developmental lineages leading to the formation of granulocytes, red blood cells, monocytes and megakaryocytes. The maturation of these cells occurs under the influence of colony-stimulating factors (CSF) and a number of interleukins, including IL-1, IL-3, IL-4, IL-5 and IL-6. They all play important role in the positive regulation (stimulation) of hematopoiesis and are produced mainly by bone marrow stromal cells, but also by mature forms of differentiated myeloid and lymphoid cells. Other cytokines (eg, TRF-beta) may down-regulate (suppress) hematopoiesis.

All cells of both the lymphoid and myeloid series have a limited lifespan, and they are all continuously formed.

In mammals during intrauterine development HSCs are present in the yolk sac, liver, spleen and bone marrow. In the adult body, hematopoietic stem cells are found mainly in the bone marrow, where they normally divide quite rarely, producing new stem cells (self-renewal). An animal can be saved from the effects of radiation at lethal doses by introducing bone marrow cells that populate its lymphoid and myeloid tissues.

Pluripotent stem cells give rise to committed progenitor cells that are already irreversibly determined to be the ancestors of one or more types of blood cells. It is believed that committed cells divide quickly, but a limited number of times, and they divide under the influence of microenvironmental factors: neighboring cells and soluble or membrane-bound cytokines. At the end of this series of divisions, these cells become terminally differentiated, usually no longer divide and die after a few days or weeks. Pluripotent stem cells are few in number, difficult to recognize, and it is still unclear how they choose their path among different options development. Programming cell divisions and placing cells on a specific differentiation path (commitment) apparently also include random events. The stem cell is pluripotent because gives rise to many types of terminally differentiated cells. As for blood cells, experiments show that all classes of blood cells - both myeloid and lymphoid - originate from a common hematopoietic stem cell.

A hematopoietic stem cell develops as follows. In the embryo, hematopoiesis begins in the yolk sac, but as development progresses, this function moves to the fetal liver and, finally, to the bone marrow, where it continues throughout life. The hematopoietic stem cell, which gives rise to all blood elements, is pluripotent and populates other hematopoietic and lymphopoietic organs and self-replicates, turning into new stem cells. An animal can be saved from the effects of radiation at lethal doses by introducing bone marrow cells that populate its lymphoid and myeloid tissues.

In the adult body, hematopoietic stem cells are found primarily in the bone marrow, where they normally divide quite infrequently, producing new stem cells (self-renewal).

The progenitor cell that gives rise to a colony of red blood cells in cell culture is called an erythroid colony-forming unit, or CFU-E, and it gives rise to mature red blood cells after six or fewer division cycles. CFU-E still does not contain hemoglobin.

Hematopoiesis(haemopoesis) is called the development of blood. There are embryonic hematopoiesis, which occurs during the embryonic period

and leads to the development of blood as a tissue, and postembryonic hematopoiesis, which is the process of physiological regeneration of blood. The development of erythrocytes is called erythropoiesis, the development of granulocytes - granulocytopoiesis, platelets - thrombocytopoiesis, the development of monocytes - monocytopoiesis, the development of lymphocytes and immunocytes - lymphocyto- and immunocytopoiesis.

Embryonic hematopoiesis.

In the development of blood as a tissue during the embryonic period, 3 main stages can be distinguished, successively replacing each other:

1) mesoblastic, when the development of blood cells begins in extra-embryonic organs - wall mesenchyme yolk sac, chorion and stem (from the 3rd to the 9th week of development of the human embryo) and the first generation of blood stem cells (BSC) appears;

2) hepatic, which begins in the liver from the 5-6th week of fetal development, when the liver becomes the main organ of hematopoiesis, the second generation of HSC is formed in it.

Hematopoiesis in the liver reaches a maximum after 5 months and is completed before birth. Liver HSCs populate the thymus (here, starting from the 7-8th week, T-lymphocytes develop), the spleen (hematopoiesis begins from the 12th week) and lymph nodes (hematopoiesis is noted from the 10th week);

3) medullary (bone marrow) - the appearance of the third generation of HSC in the bone marrow, where hematopoiesis begins from the 10th week and gradually increases towards birth, and after birth the bone marrow becomes the central organ of hematopoiesis.

Hematopoiesis in the wall of the yolk sac. In humans, it begins at the end of the 2nd - beginning of the 3rd week of embryonic development. In the mesenchyme of the wall of the yolk sac, the rudiments of vascular blood, or blood islands, are isolated. In them, mesenchymal cells become rounded, lose their processes and transform into blood stem cells. The cells bordering the blood islands are flattened, interconnected and form the endothelial lining of the future vessel. Some HSCs differentiate into primary blood cells (blasts), large cells with basophilic cytoplasm and a nucleus in which large nucleoli are clearly visible. Most primary blood cells divide mitotically and become primary erythroblasts, which are large in size (megaloblasts). This transformation occurs due to the accumulation of embryonic hemoglobin in the cytoplasm of blasts, with the formation of polychromatophilic erythroblasts first, and then oxyphilic erythroblasts with a high hemoglobin content. In some primary erythroblasts, the nucleus undergoes karyorrhexis and is removed from the cells; in others, the nucleus is retained. As a result, nuclear-free and nucleated primary erythrocytes are formed, differing large size compared to normocytes and therefore called megalocytes. This type of hematopoiesis is called megaloblastic. It is characteristic of the embryonic period, but can appear in the postnatal period with some diseases ( malignant anemia). Along with megaloblastic hematopoiesis, normoblastic hematopoiesis begins in the wall of the yolk sac, in which secondary erythroblasts are formed from blasts; first they turn into polychromatophilic erythroblasts, then into normoblasts, from which secondary erythrocytes (normocytes) are formed; the size of the latter corresponds to the erythrocytes (normocytes) of an adult. The development of red blood cells in the wall of the yolk sac occurs inside the primary blood vessels, i.e. intravascularly. At the same time, extravascularly from blasts located around vascular walls, is not differentiated a large number of granulocytes - neutrophils and eosinophils. Some of the HSCs remain in an undifferentiated state and are carried by the blood stream to various organs of the embryo, where they further differentiate into blood cells or connective tissue. After reduction of the yolk sac, the liver temporarily becomes the main hematopoietic organ.

Hematopoiesis in the liver. The liver is formed approximately at the 3-4th week of embryonic life, and from the 5th week it becomes the center of hematopoiesis. Hematopoiesis in the liver occurs extravascularly, along the capillaries growing along with the mesenchyme inside the hepatic lobules. The source of hematopoiesis in the liver are blood stem cells, from which blasts are formed that differentiate into secondary erythrocytes. The process of their formation repeats the stages of formation of secondary erythrocytes described above. Simultaneously with the development of red blood cells, granular leukocytes, mainly neutrophils and eosinophils, are formed in the liver. In the cytoplasm of the blast, becoming lighter and less basophilic, a specific granularity appears, after which the nucleus acquires irregular shape. In addition to granulocytes, giant cells - megakaryocytes - are formed in the liver. By the end of the prenatal period, hematopoiesis in the liver stops.

Hematopoiesis in the thymus. The thymus is formed at the end of the 1st month of intrauterine development, and at 1-8 weeks its epithelium begins to be populated with blood stem cells, which differentiate into thymic lymphocytes. The increasing number of thymic lymphocytes gives rise to T-lymphocytes that populate the T-zones of the peripheral organs of immunopoiesis.

Hematopoiesis in the spleen. The formation of the spleen occurs at the end of the 1st month of embryogenesis. From the stem cells that move here, the extravascular formation of all types of blood cells occurs, i.e. spleen in embryonic period is a universal hematopoietic organ. The formation of erythrocytes and granulocytes in the spleen reaches its maximum at the 5th month of embryogenesis. After this, lymphocytopoiesis begins to predominate.

Hematopoiesis in lymph nodes . The first buds of human lymph nodes appear at the 7-8th week of embryonic development. Most lymph nodes develop at 9-10 weeks. During the same period, blood stem cells begin to penetrate the lymph nodes, from which early stages erythrocytes, granulocytes and megakaryocytes differentiate. However, the formation of these elements is quickly suppressed by the formation of lymphocytes, which make up the bulk of the lymph nodes. The appearance of single lymphocytes occurs already during the 8-15th week of development, however, the massive “population” of lymph nodes by the precursors of T - and B-lymphocytes begins from the 16th week, when post-capillary venules are formed, through the wall of which the process of cell migration takes place. From precursor cells, lymphoblasts (large lymphocytes) differentiate, and then medium and small lymphocytes. Differentiation of T and B lymphocytes occurs in the T and B-dependent zones of the lymph nodes.

Hematopoiesis in the bone marrow. Bone marrow formation occurs in the 2nd month of embryonic development. The first hematopoietic elements appear at the 12th week of development; at this time, the bulk of them are erythroblasts and granulocyte precursors. All cells are formed from HSCs in the bone marrow shaped elements blood, the development of which occurs extravascularly. Some HSCs are retained in the bone marrow in an undifferentiated state; they can spread to other organs and tissues and become a source of development of blood cells and connective tissue. Thus, the bone marrow becomes the central organ that carries out universal hematopoiesis, and remains so throughout postnatal life. It provides hematopoietic stem cells to the thymus and other hematopoietic organs.

Postembryonic hematopoiesis. Postembryonic hematopoiesis is a process of physiological blood regeneration (cellular renewal), which compensates for the physiological destruction of differentiated cells.

Myelopoiesis occurs in myeloid tissue (textus myeloideus), located in the epiphyses of tubular bones and the cavities of many spongy bones.

Here the formed elements of blood develop: red blood cells, granulocytes, monocytes, blood platelets, precursors of lymphocytes.

Myeloid tissue contains blood and connective tissue stem cells.

Lymphocyte precursors gradually migrate and populate organs such as the thymus, spleen, lymph nodes, etc.

Lymphopoiesis occurs in lymphoid tissue(textus lymphoideus), which has several varieties, presented in the thymus, spleen, and lymph nodes. It performs the main functions: the formation of T - and B-lymphocytes and immunocytes (plasmocytes, etc.).

Myeloid and lymphoid tissues are types of connective tissue, i.e. relate to tissues internal environment. They present two main cell lines- cells of reticular tissue and hematopoietic.

Reticular, as well as fat, mast and osteogenic cells, together with the intercellular substance (matrix), form the microenvironment for

hematopoietic elements. Structures of the microenvironment and hematopoietic

cells function in an inextricable connection. The microenvironment has

influence on the differentiation of blood cells (upon contact with their receptors or by releasing specific factors).

It is typical for myeloid and all types of lymphoid tissue

the presence of stromal reticular and hematopoietic elements,

forming a single functional whole. The thymus has a complex stroma, represented by both connective tissue and reticuloepithelial cells. Epithelial cells secrete special substances - thymosins, which influence the differentiation of T-lymphocytes from HSCs. In the lymph nodes and spleen specialized reticular cells create the microenvironment necessary for proliferation and differentiation in special T - and B-zones of T - and B-lymphocytes and plasma cells.

HSCs are pluripotent (pluripotent) precursors of all blood cells and belong to a self-sustaining population of cells. They rarely share. The idea of ancestral blood cells was first formulated at the beginning of the 20th century by A. A. Maksimov, who believed that in their morphology they are similar to lymphocytes. Currently, this idea has been confirmed and further developed in the latest experimental studies conducted mainly on mice. Detection of CCM became possible using the colony formation method.

It has been shown experimentally (on mice) that when lethally irradiated animals (who have lost their own hematopoietic cells) are injected with a suspension of red bone marrow cells or a fraction enriched with HSCs, colonies of cells appear in the spleen - the descendants of one HSC. The proliferative activity of HSCs is modulated by colony-stimulating factors (CSF), interleukins (IL-3, etc.). Each SSC in the spleen forms one colony and is called a splenic colony-forming unit (CFU-C).

Colony counting allows one to judge the number of stem cells present in the injected cell suspension. Thus, it was found that in mice there are about 50 stem cells per 105 bone marrow cells, 3.5 cells from the spleen, and 1.4 cells among blood leukocytes.

Study of the purified stem cell fraction using electron microscope suggests that their ultrastructure is very close to small dark lymphocytes.

The study of the cellular composition of the colonies made it possible to identify two lines of their differentiation. One line gives rise to a multipotent cell - the ancestor of the granulocytic, erythrocyte, monocyte and megakaryocytic series of hematopoiesis (CFU-GEMM). The second line gives rise to a multipotent cell - the ancestor of lymphopoiesis (CFU-L). From multipotent cells, oligopotent (CFU-GM) and unipotent parent (progenitor) cells are differentiated.

The colony formation method was used to determine the parental unipotent cells for monocytes (CFU-M), neutrophil granulocytes (CFU-Gn), eosinophils (CFU-Eo), basophils (CFU-B), erythrocytes (BFU-E and CFU-E), megakaryocytes (CFU -MGC), from which progenitor cells (precursor) are formed. In the lymphopoietic series, unipotent cells are distinguished - precursors for B-lymphocytes and, accordingly, for T-lymphocytes. Multipotent (pluripotent and multipotent), oligopotent and unipotent cells are not distinguished morphologically.

All the above stages of cell development make up four main compartments: I - blood stem cells (pluripotent, pluripotent); II - committed ancestral cells (multipotent); III - committed ancestral (progenitor) oligopotent and unipotent cells; IV - progenitor cells (precursor).

The differentiation of pluripotent cells into unipotent ones is determined by the action of a number of specific factors - erythropoietins (for erythroblasts), granulopoietins (for myeloblasts), lymphopoietins (for lymphoblasts), thrombopoietins (for megakaryoblasts), etc.

From each precursor cell, a specific type of cell is formed. The maturation of each cell type goes through a series of stages, which together form the maturing cell compartment (V).

Mature cells represent the last compartment (VI). All cells of compartments V and VI can be identified morphologically.

Fig. 18. Postembryonic hematopoiesis, staining of azures with 11-eosin (scheme according to NYurina). Stages of blood differentiation: I-IV - morphologically unidentifiable cells; V - VI - morphologically identifiable cells. B - basophil; BFU - burst unit; G - granulocytes; Gn - neutrophilic granulocyte; CFU - colony forming! units; CFU-S - splenic colony-forming unit; L - lymphocyte; Lek - mt foid stem cell; M - monocyte; Met - megakaryoshgg; Eo - eosinophil; E - erythrocyte.

Rice. 19.

A - segmented neutrophilic granulocyte; B - eosinophilic (acidophilic) granulitis; B - basophilic fanulocyte: 1 - nuclear segments; 2 - sex chromatin body; 3 - primary (azurophilic) granulocytes; 4 - secondary (specific) granules; 5 - mature specific eosinophil granules containing crystalloids; b - basophil granules of various sizes and densities; 7 - peripheral zone not containing organelles; 8 - microvilli and pseudopodia.

Rice. 20. Embryonic hemoppep (according to A.A. Maksimov).

A - hematopoiesis in the wall of the yolk sac of the embryo guinea pig: 1 - small cells; 2 - endothelium of the vascular wall; 3 - primary blood cells-blasts; 4 - mitotic division of blasts; B - cross section of a blood island of a rabbit embryo S"/j day: I - vascular cavity; 2 - endothelium; 3 - intravascular blood cells; 4 - dividing blood cell; 5 - formation of a primary blood cell; 6 - endoderm; 7 - visceral layer mesoderm. B - secondary development); erythroblasts in the vessel of the rabbit embryo on day 13: 1 - endothelium; 2 - proerythroblasts; 3 - basophilic erythroblasts; 4 - polychromatophilic erythroblasts; 5 - oxyphilic erythroblasts (normoblasts); 6 - oxyphilic erythroblast with a pyknotic nucleus; 7 - separation of the nucleus from the oxyphilic erythroblast (normoblast); 8 - pushed out normoblast nucleus; 9 - secondary erythrocyte. D - hematopoiesis in the bone marrow of a human embryo with a body length of 77 mm. Extra zygomatic development of blood cells: 1 - vascular endothelium; 2 - blasts; 3 - neutrophil granulocytes; 4 - eoeinophilic myelocyte.

Update cellular composition damaged organ without surgical intervention, decide the most difficult tasks, which were previously only possible through organ transplantation - these problems are solved today with the help of stem cells.

For patients, this is a chance to get a new life. The important thing here is that the technology of using stem cells is available to almost every patient and gives truly amazing results, expanding the possibilities of transplantation.

Stem cells are capable of transforming, depending on their environment, into tissue cells of a wide variety of organs. One stem cell produces many active, functional descendants.

Research into genetic modifications of stem cells is being conducted all over the world, and methods for increasing them are being intensively researched.

There are many diseases that have practically no cure or their treatment is ineffective by medication. It is these diseases that have become the object of the closest attention of researchers.

Stem cells, regeneration, tissue repair. From Adam to the atom

What are stem cells?

When an egg is fertilized, one zygote (fertilized cell) divides and gives rise to cells whose main task is to transmit genetic information to the next generations of cells.

These cells do not yet have their own specialization, the mechanisms of such specialization have not yet been turned on, and that is why such embryonic stem cells make it possible to use them to create any organs.

Each of us has stem cells. They were initially discovered in bone marrow tissue. The easiest way to detect and isolate stem cells is in young people and children. But older people also have them, although in much smaller quantities.

Compare: a person aged 60–70 years has only one stem cell per five to eight million cells, and an embryo has one stem cell per ten thousand.

Possibilities of adult stem cells – Sergey Kiselev

What is the secret of stem cells?

The secret of stem cells is that, being immature cells themselves, they can turn into a cell of any organ.

As soon as the body's stem cells receive a signal about damage to tissues or any organs, they are sent to the site of the lesion. There they turn into precisely those cells of human tissue or organs that need protection.

Stem cells can develop and become any type of cell: hepatic, nervous, smooth muscle, mucous. Such stimulation of the body leads to the fact that it itself begins to actively regenerate its own tissues and organs.

An adult has a very small supply of stem cells. Therefore, the older a person is, the more difficult and with greater complications is the process of regeneration and restoration of the body after damage or during illness. Especially if the damage to the body is extensive.

The body cannot regenerate lost stem cells on its own. Development in the area modern medicine Today they make it possible to introduce stem cells into the body and, most importantly, direct them in the right direction. Thus, for the first time, it becomes possible to treat such dangerous diseases as cirrhosis, diabetes, and stroke.

Garyaev, Pyotr Petrovich - How to manage stem cells

Sources of stem cells

The source of stem cells in the body is primarily the bone marrow. Some, but very small, amounts of them are found in other human tissues and organs, in the peripheral blood. Many stem cells contain blood from umbilical vein newborns.

Umbilical cord blood as a source of stem cells has a number of undoubted advantages.

First of all, it is much easier and painless to collect than peripheral blood. Such blood provides genetically ideal stem cells in case of need for its use by close relatives - mother and child, brothers and sisters.

During a transplant, the immune system newly created from the donor's stem cells begins to fight the patient's immune system. This is very dangerous for the patient's life. The human condition in such cases is extremely severe, up to deaths. The use of cord blood during transplantation significantly reduces such complications.

In addition, there are a number of undoubted advantages of using umbilical cord blood.

This is the infectious safety of the recipient. Infectious diseases (cytomegalovirus and others) are not transmitted from the donor through cord blood.
If it was collected at the time of a person’s birth, then he can use it at any time to restore health.
The use of blood from the umbilical vein of newborns does not raise ethical problems, since it is then disposed of.

Application of stem cells

Stem cells were first used to treat anemia in 1988 in France.

Highly effective treatment with stem cells for tumors, strokes, heart attacks, injuries, burns, has forced the creation in developed countries of special institutions (banks) for storing frozen stem cells for a long time.

Today it is already possible, at the request of relatives, to place a child’s umbilical cord blood into such a commercial personalized blood bank, so that in the event of his injury or illness, there is an opportunity to use his own stem cells.

An internal organ transplant restores a person’s health only if it is performed in a timely manner and the organ is not rejected by the patient’s immune system.

Approximately 75% of patients requiring organ transplants die while waiting. Stem cells could be an ideal source of “spare parts” for humans.

Today, the range of applications of stem cells in the treatment of the most severe diseases is very wide.

Restoring nerve cells allows you to restore capillary circulation and cause growth capillary network at the site of the lesion. To treat a damaged spinal cord, injection of neural stem cells is used, or pure cultures, which will then turn into nerve cells in place.

Some forms of leukemia in children have become curable thanks to advances in biomedicine. Hematopoietic stem cell transplantation is used in modern hematology, and bone marrow stem cell transplantation is used in a wide range of clinical settings.

Extremely difficult to treat systemic diseases caused by dysfunction of the immune system: arthritis, multiple sclerosis, lupus erythematosus, Crohn's disease. Hematopoietic stem cells are also applicable in the treatment of these diseases

There is practical clinical experience in the use of neural stem cells in the treatment of Parkinson's disease. The results exceed all expectations.

Mesinchymal (stromal) stem cells are already used in several orthopedic clinics recent years. With their help, damaged articular cartilage and bone defects after fractures are restored.

In addition, these same cells have been used in the last two to three years by direct injection in the clinic for the restoration of heart muscle after a heart attack.

The list of diseases that can be treated with stem cells is growing every day. And this gives hope for life to incurable patients.

List of diseases treated with stem cells

Benign diseases:

adrenoleukodystrophy;
Fanconi anemia;
osteoporosis;
Gunther's disease;
Harler's syndrome;
thalassemia;
idiopathic aplastic anemia;
multiple sclerosis;
Lesch-Nyhan syndrome;
amegakaryocytotic thrombocytopenia;
Kostman's syndrome;
lupus;
resistant juvenile arthritis;
immunodeficiency states;
Crohn's disease;
Bar's syndrome;
collagenoses.

Malignant diseases:

non-Hodgkin's lymphoma;
myelodysplastic syndrome;
leukemia;
breast cancer;
neuroblastoma.

Miracles of medical and aesthetic cosmetology

A person’s desire to look young and fit for decades is due to the modern pace of life. Is it possible to look as good at fifty as at forty?

Medical cosmetics, using modern biotechnologies, provide this opportunity. Today it is possible to significantly improve skin turgor and elasticity, and relieve a person from eczema and dermatitis.

Stem cells, which are introduced during mesotherapy, eliminate skin pigmentation, scars, and the consequences of exposure to chemicals and lasers. Wrinkles and acne spots disappear, skin tone improves.

In addition, with the help of mesotherapy, problems of hair and nails are solved. They acquire healthy looking, their growth is restored.

However, when using highly effective cosmetic products, you should beware of scammers advertising products that allegedly contain stem cells.

Cost of stem cell treatment

Stem cell treatment is carried out in many countries, including Russia. Here it ranges from 240,000 to 350,000 rubles.

The high price is justified by the high-tech process of growing stem cells.

In medical centers, for this price, a patient is given one hundred million cells per course. If a person is more than mature, it is possible to administer this amount in one procedure.

The cost of procedures, as a rule, does not include manipulations to obtain stem cells. If stem cells are introduced during surgery, you will have to pay separately for this type of medical services.

Mesotherapy is more accessible today. For those who want to get a pronounced cosmetic effect, the approximate cost of one procedure in Russia will cost from 15,000 to 30,000 rubles. In total, you need to do from five to ten of them per course.

Forewarned is forearmed

Realizing the brilliant future of the use of new medical technologies, however, I would like to warn against excessive optimism and remind you of the following:

Stem cells are an unusual drug whose effects are difficult to reverse. The fact is that stem cells, unlike other drugs, are not removed from it in the same way as conventional drugs. They contain living cells, and their behavior is not always predictable. If harm is caused to the patient’s body, doctors cannot stop the process;
Medical scientists hope that side effects from stem cell treatment will be minimal. But one cannot even assume that side effect will not occur during treatment. Like any medicine, even aspirin, stem cells have limitations and side effects in their use;
Clinical trials in leading medical centers have only confirmed that bone marrow transplantation is so far the only method of cell therapy;
The use of stem cells is not a panacea for the treatment of absolutely all diseases, although they do have great potential in the treatment of many injuries, burns, injuries and diseases;
Even if many famous people, athletes, politicians use stem cell treatment, this does not mean that such a method treatment is suitable everyone. It is necessary to trust practicing doctors.

Is immortality possible?

Human immortality is possible – the achievements of modern medicine convince us of this.

Fantastic ideas about synthesis human organs are already turning into a reality of the near future. Ten years will pass and artificial kidneys, hearts, and livers will become available to every person. Simple injections will restore the skin and rejuvenate it. The main credit for this will belong to stem cells.

Stem cells are undifferentiated cells that, as a “strategic reserve,” are present in the human body at any stage of his life. A special feature is their unlimited ability to divide and the ability to give rise to any type of specialized human cells.

Thanks to their presence, gradual cellular renewal of all organs and tissues of the body and restoration of organs and tissues after damage occurs.

History of discovery and research

The Russian scientist Alexander Anisimov was the first to prove the existence of stem cells. This happened back in 1909. Their practical application became of interest to scientists much later, around 1950. It was only in 1970 that stem cells were first transplanted into patients with leukemia, and this method treatment began to be used throughout the world.

Around this time, the study of stem cells was singled out as a separate area, separate laboratories and even entire research institutes began to appear, developing methods of treatment using progenitor cells. In 2003, the first Russian biotechnology company appeared, called the Human Stem Cell Institute, which today is the largest repository of stem cell samples, and also promotes its own innovative technologies on the market. medications and high-tech services.

At this stage in the development of medicine, scientists have managed to obtain an egg from a stem cell, which in the future will allow infertile couples to have their own children.

Video: Successful biotechnologies

Where are progenitor cells located?

Stem cells can be found in almost every part of the human body. They're in mandatory present in any tissue of the body. Their maximum amount in an adult is contained in the red bone marrow, slightly less in the peripheral blood, adipose tissue, and skin.

The younger an organism is, the more of them it contains, the more active these cells are in terms of the rate of division, and the wider the range of specialized cells to which each progenitor cell can give life.

Where do they get the material from?

Embryonic.

The most “delicious” for researchers are embryonic stem cells, since the shorter the organism has lived, the more plastic and biologically active the precursor cells are.

But if it is not a problem for researchers to obtain animal cells, then any experiments using human embryos are considered unethical.

This is even though, according to statistics, approximately every second pregnancy in modern world ends in abortion.

From umbilical cord blood.

Available in terms of morality and legislative decisions in a number of countries are stem cells from umbilical cord blood, the umbilical cord itself and the placenta.

Currently, entire banks of stem cells isolated from umbilical cord blood are being created, which can subsequently be used to treat a number of diseases and the consequences of body injuries. On a commercial basis, numerous private banks offer parents a personal “deposit” for their child.

It is believed that to restore hematopoiesis after chemotherapy or radiotherapy, only a child up to of a certain age and body weight (up to 50 kg).

But it is not always necessary to restore such a large amount of tissue. To restore, for example, the same cartilage knee joint Only a small portion of the preserved cells will be sufficient.

The same applies to the restoration of cells of the damaged pancreas or liver. And since stem cells from one portion of umbilical cord blood are divided into several cryovials before freezing, it will always be possible to use a small part of the material.

Obtaining stem cells from an adult.

Not everyone is lucky enough to receive their “emergency supply” of stem cells from umbilical cord blood from their parents. Therefore, at this stage, methods are being developed to obtain them from adults.

The main tissues that can serve as sources are:

adipose tissue (taken during liposuction, for example);
peripheral blood, which can be taken from a vein);
red bone marrow.

Adult stem cells obtained from different sources may have some differences due to the cells losing their versatility. For example, blood and red bone marrow cells can give rise predominantly to blood cells. They are called hematopoietic.

And stem cells from adipose tissue differentiate (degenerate) much more easily into specialized cells of organs and tissues of the body (cartilage, bones, muscles, etc.). They are called mesenchymal.

Depending on the scale of the task that scientists face, they may need different numbers of such cells. For example, methods are now being developed to grow teeth obtained from urine from them. There aren't that many of them there.

But given the fact that a tooth needs to be grown only once, and its service life is significant, it does not require much stem cells.

Video: Pokrovsky Stem Cell Bank

Storage banks for biological material

Special jars are created to store samples. Depending on the purpose of storing the material, they may be state owned. They are also called registrar banks. Registrars store stem cells from anonymous donors and may, at their discretion, provide the material to any medical or research institutions.

There are also commercial banks that make money by storing samples from specific donors. Only their owners can use them to treat themselves or close relatives.

If we talk about the demand for samples, the statistics are as follows:

every thousandth sample is in demand at registrar banks;
material stored in private banks is even less often in demand.

However, it makes sense to keep a registered sample in a private bank. There are several reasons for this:

Donor samples cost money, sometimes quite a lot, and the amount required to purchase a sample and deliver it to the right clinic is often many times greater than the cost of storing your own sample for several decades;
a nominal sample can be used to treat blood relatives;
It can be assumed that in the future, organs and tissues will be restored using stem cells much more often than is happening in our time, and therefore the demand for them will only grow.

Application in medicine

In fact, the only direction of their use that has already been studied is bone marrow transplantation as a stage in the treatment of leukemia and lymphomas. Some research on the reconstruction of organs and tissues using stem cells has already reached the stage of conducting experiments on humans, but there is no talk of mass introduction into the practice of doctors yet.

To obtain new tissues from stem cells, it is usually necessary to perform the following manipulations:

collection of material;
stem cell isolation;
growing stem cells on nutrient substrates;
creating conditions for the transformation of stem cells into specialized ones;
reducing the risks associated with the possibility of malignant degeneration of cells obtained from stem cells;
transplantation.

Stem cells are isolated from tissues taken for the experiment using special devices called separators. There are also various techniques sedimentation of stem cells, but their effectiveness is largely determined by the qualifications and experience of the personnel, and there is also a risk of bacterial or fungal infection sample.

The resulting stem cells are placed in a specially prepared medium that contains lymph or blood serum of newborn calves. On a nutrient substrate, they divide many times, their number increases several thousand times. Before introducing them into the body, scientists direct their differentiation in a certain direction, for example, they obtain nerve cells, liver or pancreatic cells, a cartilage plate, etc.

It is at this stage that there is a danger of their degeneration into tumors. To prevent this, special techniques are being developed to reduce the likelihood of cancerous degeneration of cells.

Methods of introducing cells into the body:

introduction of cells into tissue directly at the site where there was injury or tissue was damaged as a result pathological process(diseases): injection of stem cells into the area of hemorrhage in the brain or to the site of injury peripheral nerves;
introduction of cells into bloodstream: This is how stem cells are administered in the treatment of leukemia.

Pros and cons of using stem cells for rejuvenation

Study and use in the media is increasingly cited as a way to achieve immortality or at least longevity. Already in the distant 70s, stem cells were administered to elderly members of the CPSU Politburo as a rejuvenating agent.

Now, when a number of private biotechnology research centers have appeared, some researchers have begun to carry out anti-aging injections of stem cells previously taken from the patient himself.

This procedure is quite expensive, but no one can guarantee its result. When agreeing, the client must be aware that he is participating in an experiment, since many aspects of their use have not yet been studied.

Video: What Stem Cells Can Do

The most common types of procedures are:

introduction of stem cells into the dermis (the procedure is somewhat reminiscent of biorevitalization);
filling skin defects, adding volume to tissues (this is more like using fillers).

In the second case, the patient’s own adipose tissue and his stem cells are used in a mixture with stabilized hyaluronic acid. Experiments on animals have shown that such a cocktail allows more adipose tissue to take root and maintain volume for a long time.

The first experiments were carried out on people who, using this technique, had wrinkles removed and mammary glands enlarged. However, the data is not yet sufficient for any of the doctors to repeat this experience on your patient, providing him with a guaranteed result.