Regeneration process. Regeneration. Types of regeneration. Physiological regeneration, its meaning. The manifestation of physiological regeneration at the subcellular, cellular and tissue levels. Kirov State Medical Institute

Regeneration is the process of repairing damage. This process underlies the repair of damage to organelles and cells. Therefore, depending on the level of regeneration, intracellular and cellular regeneration are distinguished.

When a single cell is damaged, mitochondria, for example, recover well. If many cells are damaged, then recovery is possible due to cell multiplication. However, in the course of evolution, this ability to reproduce was formed differently in different cells.

The mechanisms of regeneration are associated with a violation of contact inhibition, a decrease in the number of keylons in cells and the formation of special chemicals - trephons, which stimulate cell multiplication. Keylones usually cause inhibition of proliferation. When cells are damaged, the number of keylons in them decreases, and they acquire the ability to reproduce.

The epithelium, vascular endothelium, fibroblasts, bone marrow cells, lymph nodes, bone cells, periosteum can regenerate well, liver cells, endocrine gland cells, and renal tubular epithelium can regenerate.

Limited regenerative capacity is characteristic of myofibrils of skeletal smooth muscle cells.

Virtually no nerve cells are regenerated. Regeneration is possible if the axons of the nerve cell (nerves) are damaged, but this process is very slow. This option is possible, i.e. the distal end of the nerve (for example, after trauma or transection) regenerates. If the neurolemma is aligned with the axon growth section in the distal direction, regeneration proceeds at a rate of 20 mm per week.

Due to the fact that in the damaged area, recovery is not due to specialized cells, but due to epithelial, endothelial, fibroblasts, recovery often occurs with the formation of a connective tissue, and if nerve cells are damaged, a glial scar. Therefore, in muscles, nervous tissue, and in

In other organs, restoration (healing) of the damaged area occurs due to the formation of a scar.

Hypertrophy and hyperplasia

Hyperplasia is a constituent element of hypertrophy and is characterized by an increase in the number of structural elements of the cell, for example, mihotondria, lysosomes, endoplasmic reticulum, etc. Hypertrophy (hyper - increase, trophe - feed) is characterized not only by an increase in intracellular organelles, the cell itself, but also the organ as a whole. Depending on the origin, it is divided into physiological and pathological. Physiological hypertrophy is observed in athletes (hypertrophy of the striated muscles and heart), pregnant women and women in labor (hypertrophy of the uterus and mammary glands). Pathological hypertrophy occurs when organ cells are damaged or functional load increases, for example, hypertrophy of the heart (with myocardial infarction), paired organ (removal of the kidney, lung).

The mechanism of hypertrophy is based on a deficit of energy with the subsequent activation of the genetic apparatus of the cell. As a result, protein synthesis is enhanced, mitochondrial hyperplasia and an improvement in the formation of macroergs, with a further enhancement of synthetic processes in the cells of the organ.

Atrophy is a process in a cell, which is characterized by a decrease in the size of not only all its organelles, but also the cell itself, which is usually associated with a lack of nutrients, a decrease in functional load and regulatory influences.

By origin, it is divided into physiological and pathological.

Physiological atrophy is observed with age in various tissues and organs of a person (skin, mucous membranes, gonads, etc.). Under pathological conditions, atrophy is observed during starvation (in fat and muscle cells), with peripheral (atrophic) paralysis, in the peripheral endocrine glands with a deficiency of thyrotropin, corticotropin, and gonadotropins. Muscle atrophy also develops during physical inactivity (for example, it is possible in astronauts) or in immobilized patients. It also forms when the motor nerve is transected (peripheral paralysis).

Thus, in the classical form, pathological atrophy develops with a deficiency of nutrients, restriction of movement, denervation, and dysregulation of peripheral glands. To this it should be added that if atrophy can be considered as a compensatory process under the above conditions at the level of the cell, then at the organ, system and organism level it is a factor of damage and causes serious disorders.

So, as a result of the direct action of the damaging factor or the involvement of the above general mechanisms of damage, the structure of the cell is disrupted. The main morphological signs of damage are: dystrophy, dysplasia, violation of the structure of intracellular organelles, necrobiosis and necrosis. At the same time, the function of the cell also changes. For example, the phagocytic activity of leukocytes decreases, the resting and action potential changes, which can be manifested by a change in the electrocardiogram, myogram, encephalogram, etc.

Dystrophy (dis - disorder, trophe - nourish) is a process that occurs in cells and tissues, which is based on a malnutrition of cells, is characterized by quantitative and qualitative changes in metabolic processes.

Dystrophy of any origin is based on disorders of regulation of nutrition (trophism) of the cell. Depending on the nature of metabolic disorders, the following dystrophies are distinguished: protein, carbohydrate, fat and mineral. Dystrophic processes can occur both in specialized cellular elements of the parenchyma and in the stroma. Depending on the prevalence of dystrophy, it can be local or systemic.

Protein dystrophy is associated with excessive accumulation of protein in cells or intercellular substance. The accumulation of protein in the parenchyma can be manifested by the formation of granularity, hyaline drops, vacuoles. In the mesenchyme, this is manifested by mucous edema, fibrinoid changes, fibrinolysis, accumulation of hyaline and amyloid. For example, in amyloid dystrophy, which occurs during chronic inflammation or monoclonal proliferation of plasma cells, in tumors of the endocrine glands with excessive secretion, for example, calcitonin, insulin. Usually in these cases, amyloid A or L can accumulate.

As a rule, all tissues and organs are affected, but especially the kidneys, gastrointestinal tract and heart. Moreover, amyloid accumulates around the capillaries and along the muscle fibers, in the basement membrane of the kidney tubules. Due to mechanical pressure, atrophy of cells (tubules, cardiomyocytes) occurs, and capillary permeability increases. As a result, a large amount of protein is lost in the kidneys due to increased capillary permeability and impaired reabsorption with urine, absorption is impaired in the gastrointestinal tract. Therefore, diarrhea develops with the loss of large amounts of fluids, nutrients and electrolytes. In cardiomyocytes, shrinkage and impairment of their contractility occur. Thus, amyloidosis, in turn, is the most important link in further cell damage.

Mixed forms of protein dystrophies are associated with the accumulation of such complex products as hemosiderin, melanin, bilirubin, nucleoprotein, glycoprotein. Such dystrophies develop with hemolysis of erythrocytes, jaundice, gout. For example, melanin is a pigment and is normally found in the skin, iris, and adrenal glands. It is formed by melanocytes, captured by epithelial cells, and they become darker.

Melanin is destroyed by melanophores, which phagocytose it. The accumulation of melanin in cells can be local in nature, for example, in tumors such as melanoma or during pregnancy, when age spots appear on the face. A generalized nature of pigmentation is possible, for example, with ultraviolet radiation or primary adrenal insufficiency. The mechanism of such systemic changes is due to the excessive secretion of melanotropin from the pituitary gland, which stimulates melanocytes.

Fatty degeneration or lipidosis. It is characterized by a change in the amount of neutral fat. This, as a rule, is manifested by an increase (obesity) or a decrease (emaciation, cachexia) in the amount of fat not only in fat depots, but also in other organs. Local depletion of adipose tissue (lipodystrophy) is observed in the area of ​​subcutaneous insulin administration, with organ atrophy.

Especially often a violation of lipid metabolism, like protein metabolism, occurs in organs such as the kidneys, heart, liver. In old age, with diabetes, systemic obesity, fatty degeneration develops in the cells of the vascular endothelium (atherosclerosis, where lipids are deposited in the intima, forming a plaque that undergoes fibrosis).

Carbohydrate dystrophy is associated with impaired metabolism of complex carbohydrates such as poly -, mucopolysaccharides, glycoproteins.

In the classical version, this type of dystrophy is associated with a change in the amount of such a polysaccharide as glycogen. Its content in cells can increase with the so-called. hereditary enzymopathies, when due to a violation of the formation of enzymes (for example, glucose-6-phosphatase) glycogen is deposited in the cell, but cannot be mobilized. These dystrophic changes are called glycogenosis. They are usually characterized by a sharp increase in the liver and kidneys and a decrease in the amount of glucose in the blood.

On the other hand, during fasting, diabetes mellitus, the content of glycogen in cells decreases sharply. The content of glycoproteins in the form of mucins increases in the cell with a lack of thyroid hormones. A large accumulation of mucins leads to mucous edema, one of the most characteristic manifestations of myxedema.

Mineral dystrophies are associated with metabolic disorders of iron, copper, potassium, calcium. The accumulation of these minerals (iron, copper, potassium, calcium) in cells is observed in hemosiderosis, hepatocerebral dystrophy, calcification, and corticosteroid insufficiency.

Loss of calcium by bone cells is the basis of osteoporosis.

Dysplasia (dis - disorder, plaseo - form). This is such a violation of the cell, which is based on the violation of its genome, the consequence of which is a persistent change in the structure and function of the cell. In the foreground is the violation of cell differentiation. Therefore, both the structure and function of such a cell is different from that of the mother. Dysplasia is most typical for tumor cells, which in the course of tumor progression (selection) change the size, shape, number of organelles, and biochemical processes are activated. Such cells, multiplying, are able to infiltrate healthy tissues and metastasize. Disorders of intracellular organelles can manifest themselves in a change in their structure, number and, consequently, their functional activity.

Necrosis. As a result of the direct action of the destructive factor on the cell membrane or with a slight change in its permeability, sodium and calcium ions, water, and it swells first of all into the cell. Swelling is also noted from the side of intracellular organelles, followed by rupture of their membranes, disintegration and cell death. The death of a part of the cells of an organ or tissue in a living organism is called necrosis. In this case, activated enzymes and potassium enter the bloodstream and can be used as a diagnostic test.

There are two types of necrosis:

1. Coagulation.

2. Colliquation.

Coagulation necrosis is associated with the cessation of blood flow (infarction) and is microscopically characterized by changes in the nucleus such as karyolysis or karyorrhexis, cytoplasm, which becomes opaque due to protein coagulation. Depending on the nature of the circulatory disorder (ischemia or venous hyperemia), the infarction is called ischemic or venous (stagnant).

Colliquation necrosis occurs in organs containing a large amount of fluid, the presence of which contributes to the activation of lysosomal enzymes that lyse cell components with a complete disruption of its structure, as a result of which the necrotic area undergoes softening. A classic example of such necrosis is an abscess, intestinal necrosis, brain cells.

If cells after necrosis undergo self-digestion under the action of activated enzymes, this process is called autolysis. They can also be resorbed under the influence of the phagocytic activity of leukocytes.

A complication of necrosis is gangrene, in which the necrotic area is mummified or exposed to rotting microorganisms. In this case, in the latter case, foul-smelling gases are formed, and the gangrene area becomes black due to the breakdown of hemoglobin. Angrene usually develops against the background of impaired blood circulation, (for example, with diabetes on the foot; in the intestine with its volvulus or intussusception). When infected with a special organism, gas gangrene occurs.

If only individual cells, surrounded by healthy ones, die, this phenomenon is called necrobiosis. At the same time, due to active metabolic processes in the cell, destruction of the nucleus, cytoplasm and even cellular disintegration occurs. Nearby lying cells phagocytose decay products. This is a physiological process and therefore no inflammation develops. Under pathological conditions, this phenomenon is observed in atrophy and in tumors.

VOLGOGRAD STATE ACADEMY OF PHYSICAL CULTURE

abstract

in biology

on the topic of:

“Regeneration, its types and levels. Conditions affecting the course of recovery processes "

Completed: student group 108

Timofeev D. M

Volgograd 2003

Introduction

1. The concept of regeneration

2. Types of regeneration

3. Conditions affecting the course of recovery processes

Conclusion

Bibliography

Introduction

Regeneration is the renewal of the body's structures in the process of vital activity and the restoration of those structures that have been lost as a result of pathological processes. To a greater extent, regeneration is inherent in plants and invertebrates, to a lesser extent in vertebrates. Regeneration - in medicine - the complete restoration of lost parts.

The phenomena of regeneration have been familiar to people since ancient times. By the end of the 19th century. material has been accumulated that reveals the laws of the regenerative reaction in humans and animals, but the problem of regeneration has been developed especially intensively since the 40s. 20th century

Scientists have long been trying to understand how amphibians - for example, newts and salamanders - regenerate severed tails, limbs, and jaws. Moreover, the damaged heart, eye tissues, and spinal cord are also restored. The method used by amphibians for self-repair became clear when scientists compared the regeneration of mature individuals and embryos. It turns out that in the early stages of development, the cells of the future creature are immature, their fate may well change.

In this essay, the concept will be given and the types of regeneration will be considered, as well as the features of the course of recovery processes.

1. Regeneration concept

REGENERATION(from late Lat. regenera-tio - revival, renewal) in biology, restoration by the body of lost or damaged organs and tissues, as well as restoration of the whole organism from its part. Regeneration is observed in vivo and can also be induced experimentally.

R regeneration in animals and humans- the formation of new structures to replace those that were removed or died as a result of damage (reparative regeneration) or lost in the course of normal life (physiological regeneration); secondary development caused by the loss of a previously developed organ. A regenerated organ may have the same structure as a distant one, differ from it, or not at all resemble it (atypical regeneration).

The term "regeneration" was proposed in 1712 French. the scientist R. Reaumur, who studied the regeneration of the legs of crayfish. In many invertebrates, it is possible to regenerate a whole organism from a piece of the body. In highly organized animals this is impossible - only individual organs or their parts are regenerated. Regeneration can occur through the growth of tissues on the wound surface, the restructuring of the remaining part of the organ into a new one, or by the growth of the remainder of the organ without changing its shape . The idea of ​​a weakening of the ability to regenerate as the organization of animals increases is erroneous, since the process of regeneration depends not only on the level of organization of the animal, but also on many other factors and is therefore characterized by variability. It is also wrong to say that the ability to regenerate naturally decreases with age; it can also increase in the process of ontogenesis, but in the period of old age its decrease is often observed. Over the past quarter of a century, it has been shown that, although in mammals and humans, entire external organs do not regenerate, their internal organs, as well as muscles, skeleton, and skin, are capable of regeneration, which is studied at the organ, tissue, cellular and subcellular levels. The development of methods for enhancing (stimulating) the weak and restoring the lost ability to regenerate will bring the doctrine of regeneration closer to medicine.

Regeneration in medicine. Distinguish between physiological, reparative and pathological regeneration. In case of injuries and other pathological conditions that are accompanied by massive cell death, tissue restoration is carried out at the expense of reparative(restorative) regeneration. If, in the process of reparative regeneration, the lost part is replaced by an equivalent, specialized tissue, one speaks of complete regeneration (restitution); if non-specialized connective tissue grows at the site of the defect, about incomplete regeneration (healing through scarring). In some cases, with substitution, the function is restored due to the intensive neoplasm of tissue (similar to the dead tissue) in the intact part of the organ. This neoplasm occurs either by enhanced cell multiplication, or by intracellular regeneration - restoration of subcellular structures with an unchanged number of cells (heart muscle, nervous tissue). Age, metabolic features, the state of the nervous and endocrine systems, nutrition, the intensity of blood circulation in the damaged tissue, concomitant diseases can weaken, enhance or qualitatively change the regeneration process. In some cases, this leads to pathological regeneration. Its manifestations: long-term non-healing ulcers, disorders of the fusion of bone fractures, excessive tissue proliferation or the transition of one type of tissue to another. Therapeutic effects on the regeneration process are to stimulate complete and prevent pathological regeneration.

R plant regeneration can occur at the site of a lost part (restitution) or at another site of the body (reproduction). Spring regeneration of leaves instead of fallen leaves in autumn is a natural regeneration of the reproduction type. Usually, however, regeneration is understood only as the restoration of forcibly rejected parts. With such regeneration, the body primarily uses the main pathways of normal development. Therefore, the regeneration of organs in plants occurs mainly through reproduction: the removed organs are compensated by the development of existing or newly formed metameric structures. So, when cutting off the top of the shoot, lateral shoots develop vigorously. Plants or their parts that do not develop metamerically are easier to regenerate by restitution, just like tissue sites. For example, the wound surface may become covered with the so-called wound peridermis; a wound on a trunk or branch can heal with influxes (calluses). Propagation of plants by cuttings is the simplest case of regeneration, when a whole plant is restored from a small vegetative part.

Regeneration from sections of the root, rhizome or thallus is also widespread. You can grow plants from leaf cuttings, leaf pieces (for example, begonias). Some plants succeeded in regeneration from isolated cells and even from individual isolated protoplasts, and in some species of siphon algae - from small areas of their multinucleated protoplasm. The young age of the plant usually promotes regeneration, but at too early stages of ontogeny, the organ may be unable to regenerate. As a biological device that ensures the healing of wounds, the restoration of accidentally lost organs, and often vegetative reproduction, regeneration is of great importance for plant growing, fruit growing, forestry, ornamental gardening, etc. It also provides material for solving a number of theoretical problems, incl. and developmental problems of the body. Growth substances play an important role in the regeneration processes.

2. Regeneration types

There are two types of regeneration - physiological and reparative.

Physiological regeneration- continuous renewal of structures at the cellular (change of blood cells, epidermis, etc.) and intracellular (renewal of cellular organelles) levels, which ensure the functioning of organs and tissues.

Reparative regeneration- the process of eliminating structural damage after the action of pathogenic factors.

Both types of regeneration are not separate, independent of each other. Thus, reparative regeneration develops on the basis of physiological, that is, on the basis of the same mechanisms, and differs only in a greater intensity of manifestations. Therefore, reparative regeneration should be considered as a normal reaction of the body to damage, characterized by a sharp increase in the physiological mechanisms of reproduction of specific tissue elements of a particular organ.

The importance of regeneration for the body is determined by the fact that on the basis of cellular and intracellular renewal of organs, a wide range of adaptive fluctuations in their functional activity in changing environmental conditions is provided, as well as restoration and compensation of functions disturbed under the influence of various pathogenic factors.

Physiological and reparative regeneration are the structural basis of the whole variety of manifestations of the body's vital activity in health and disease.

The regeneration process unfolds at different levels of organization - systemic, organ, tissue, cellular, intracellular. It is carried out by direct and indirect cell division, renewal of intracellular organelles and their reproduction. Renewal of intracellular structures and their hyperplasia are a universal form of regeneration inherent in all mammalian and human organs without exception. It is expressed either in the form of intracellular regeneration itself, when after the death of a part of the cell, its structure is restored due to the reproduction of the preserved organelles, or in the form of an increase in the number of organelles (compensatory hyperplasia of organelles) in one cell upon death of another.

1

Badertdinov R.R.

The paper provides a brief overview of the achievements of regenerative medicine. What is regenerative medicine, how realistic is the application of its developments in our life? How soon can we take advantage of them? An attempt is made to answer these and other questions in this work.

regeneration

regenerative medicine

stem cells

cytogens

recovery

genetics

nanomedicine

gerontology

What do we know about regenerative medicine? For most of us, the theme of regeneration and everything connected with it is firmly associated with the fantasy plots of feature films. Indeed, due to the low awareness of the population, which is very strange, given the constant urgency and vital importance of this issue, people have a fairly stable opinion: reparative regeneration is an invention of screenwriters and science fiction writers. But is it? Is the possibility of regenerating a person really someone's fiction, with the aim of creating a more sophisticated plot?

Until recently, it was believed that the possibility of reparative regeneration of an organism, which occurs after damage or loss of any part of the body, was lost by almost all living organisms in the process of evolution and, as a result, the complication of the structure of the organism, except for some creatures, including amphibians. One of the discoveries that greatly shaken this dogma was the discovery of the p21 gene and its specific properties: blocking the body's regenerative capabilities, by a group of researchers from The Wistar Institute, Philadelphia, USA (The Wistar Institute, Philadelphia).

Experiments on mice have shown that the body of rodents with the presence of the p21 gene can regenerate lost or damaged tissue. Unlike ordinary mammals, in which wounds are healed by the formation of scars, ugenetically modified mice with damaged ears at the site of the wound forms a blastema - a structure associated with rapid cell growth. At the entrance of regeneration, tissues of the regenerating organ are formed from the blastema.

According to scientists, in the absence of the p21 gene, rodent cells behave like regenerating embryonic stem cells. Anne like mature mammalian cells. That is, they grow new tissue rather than repair damaged tissue. Here it will be appropriate to recall that the same regeneration scheme is also present in the usalamander, which has the ability to regrow not only the tail, but also the lost limbs, or uplanarium, of ciliary worms, which can be cut into several parts, and a new planarian will grow from each piece.

According to the cautious remarks of the researchers themselves, it follows that, theoretically, turning off the p21 gene can trigger a similar process in the human body. It is certainly worth noting that the p21 gene is closely related to another gene, p53. which controls cell division and prevents the formation of tumors. In normal adult cells, p21 blocks cell division in the event of DNA damage, so mice in which it has been disabled are at greater risk of cancer.

But while the researchers did find large DNA damage during the experiment, they found no traces of cancer: on the contrary, the brain's apoptosis mechanism intensified, a programmed "suicide" of cells that also protects against tumors. This combination can allow cells to divide faster without becoming "cancerous".

Avoiding far-reaching conclusions, nevertheless, we note that the researchers themselves say only the timely shutdown of this gene in order to accelerate regeneration: “While we are just beginning to understand the repercussions of these findings, perhaps, one day we´ll be able to accelerate healing in humans by temporarily inactivating the p21 gene. " Translation: "At the moment we are just beginning to understand all the consequences of our discoveries, and perhaps someday we will be able to accelerate the healing of people by temporarily inactivating the p21 gene."

And this is just one of many possible paths. Let's consider other options. For example, one of the most famous and promoted, partly with the aim of making large profits by various pharmaceutical, cosmetic and other companies - stem cells (SC). The most frequently mentioned are embryonic stem cells. Many have heard about these cells, they earn a lot of money with the help, many attribute to them truly fantastic properties. So what are they? Let's try to clarify this issue.

Embryonic stem cells (ESCs) are the niches of continuously multiplying stem cells of the inner cell mass, or embryoplast, mammalian blastocyst. Any type of specialized cell can develop from these cells, but not an independent organism. Embryonic stem cells are functionally equivalent to embryonic germ cell lines derived from primary embryonic cells. Distinctive properties of embryonic stem cells - the ability to maintain their culture in an undifferentiated state for an unlimited time and their ability to develop any cells of the body. The ability of ESCs to give rise to a large number of different cell types makes them a useful tool for basic research and a source of cell populations for new therapies. The term "embryonic stem cell line" refers to ESCs that have been maintained for a long time (months or years) under laboratory conditions in which proliferation occurs without differentiation. There are several good sources of basic information on stem cells, although published review articles quickly become outdated. One useful source of information is the National Institutes of Health (NIH), USA) website.

The characteristics of different stem cell populations and the molecular mechanisms that maintain their unique status are still being studied. At the moment, two main types of stem cells are distinguished - these are adult and embryonic stem cells. Let us highlight three important features that distinguish ESCs from other types of cells:

1.ESCs express factors associated with spuripotent cells such as Oct4, Sox2, Tert, Utfl and Rex1 (Carpenter and Bhatia 2004).

2.ESC are non-specialized cells that can differentiate into cells with special functions.

3. ESCs can self-renew by multiple divisions.

ESCs are maintained in an in vitro undifferentiated state by precise adherence to specific culture conditions, which include the presence of leukemia inhibitory factor (LIF). If LIF is removed from the environment, ESCs begin to differentiate and form complex structures called embryonic bodies and consist of cells of various types, including endothelial, nerve, muscle and hematopoietic progenitor cells.

Let us dwell separately on the mechanisms of operation and regulation of stem cells. The special characteristics of stem cells are determined not by one gene, but by a whole set of them. The possibility of identifying these genes is directly related to the development of a method for cultivating embryonic stem cells in vitro, as well as the possibility of using modern methods of molecular biology (in particular, the use of the leukemia inhibition factor LIF).

As a result of joint research by Geron Corporation and Celera Genomics, cDNA libraries of undifferentiated ESCs and partially differentiated cells were created (cDNA is obtained by synthesis based on the mRNA molecule, a complementary DNA molecule using the reverse transcriptase enzyme). When analyzing data on sequencing of nucleotide sequences and gene expression, more than 600 genes were identified, the activation or deactivation of which distinguishes undifferentiated cells, and a picture of the molecular pathways along which differentiation of these cells occurs.

Nowadays, it is customary to distinguish stem cells by their behavior in culture and by chemical markers on the cell surface. However, the genes responsible for the manifestation of these features remain unknown in most cases. Nevertheless, the studies carried out made it possible to distinguish two groups of genes that give stem cells their remarkable properties. On the one hand, the properties of stem cells are manifested in a specific microenvironment known as the stem cell niche. When studying these cells, which surround, nourish and maintain stem cells in an undifferentiated state, about 4000 genes have been found. Moreover, these genes were active in the cells of the microenvironment, inactive in all other
cells.

In the study of the germ stem cells of the Drosophila ovaries, a signaling system between stem cells and specialized “niche” cells was determined. This signaling system determines the self-renewal of stem cells and the direction of their differentiation. Regulatory genes in niche cells give instructions to stem cell genes that determine the further path of their development. Ithe, and other genes produce proteins that act as switches that start or stop stem cell division. It was found that the interaction between niche cells and stem cells, which determines their fate, is mediated by three different genes - piwi, pumilio (pum) and bam (bag of marbles). It has been shown that for the successful self-renewal of embryonic stem cells, the piwi and pum genes must be activated, while the bam gene is required for differentiation. Further studies showed that the piwi gene is part of a group of genes involved in the development of stem cells in various organisms belonging to both the animal and the growing kingdom. Genes like piwi (they are called, in this case, MIWI and MILI), pum and bam, there are mammals, including uhumans. Based on these findings, the authors hypothesize that the piwi niche cell gene mediates the division of germ cells and maintains their dedifferentiated state by suppressing the expression of the bum gene.

It should be noted that the database on genes that determine the properties of stem cells is constantly updated. A complete catalog of stem cell genes can improve the process of stem cell identification, as well as clarify the mechanisms of functioning of these cells, which will provide the differentiated cells necessary for therapeutic use, as well as provide new opportunities for drug development. The significance of these genes is great, since they provide the body with the ability to maintain itself and regenerate tissues.

Here a question may arise for the teacher: "How far have scientists advanced in the practical application of this knowledge?" Are they used in medicine? Are there any prospects for further development of these areas? To answer these questions, we will conduct a small review of scientific developments in this direction, as old ones, which should not be surprising, because research in the field of regenerative medicine has been going on for a long time, at least at the beginning of the 20th century, and completely new, sometimes very unusual and exotic.

To begin with, we note that back in the 80s of the 20th century in the USSR at the Institute of Evolutionary Ecology and Animal Morphology. Severtsev Academy of Sciences of the USSR, in the laboratory of A.N. Studitsky conducted experiments: the chopped muscle fiber was transplanted into the damaged area, which, after recovering, forced nerve tissues to regenerate. Hundreds of successful human surgeries have been performed.

At the same time, at the Institute of Cybernetics. Glushkov in the laboratory of Professor L.S. Aleeva created an electrostimulator of muscles - Meoton: the impulse of movement of a healthy person is amplified by the device and directed to the affected muscle of an immobile patient. The muscle receives a command from the muscle and makes the motionless one contract: this program is recorded in the memory of the device and the patient can work on his own in the future. It should be noted that these developments were made several decades ago. Apparently, it is these processes that lie at the heart of the program independently and independently developed and applied today by V.I. Dikul. More details about these developments can be found in the documentary film "The Hundredth Riddle of Muscle" by Yuri Senchukov, Tsentrnauchfilm, 1988.

Separately, we note that even in the middle of the 20th century, a group of Soviet scientists, under the leadership of L.V. Polezhaev, research was carried out, with the suspension of practical application of their results on the regeneration of the bones of the cranial vault of animals and humans; the defect area reached up to 20 square centimeters. The edges of the hole were covered with crushed bone tissue, which triggered the regeneration process, during which the damaged areas were restored.

In this regard, it would be appropriate to recall the so-called "Spivak's case" - the formation of the histolic phalanx of a finger of a sixty-year-old man, when processing the stump with components of the extracellular matrix (a cocktail of molecules), which was a powder from the bladder of a pig (the mention of this was a weekly analytical the program "In the center of events" on the state television channel TV Center).

Also, I would like to focus on such an everyday and familiar object as salt (NaCl). The healing properties of the sea climate, places, high salt content in the air and in the air, like the Dead Sea in Israel or Sol-Iletsk in Russia, salt mines, widely used in hospitals, sanatoriums and resorts around the world are widely known. Athletes and people leading an active lifestyle are also familiar with the salt baths used in the treatment of injuries of the musculoskeletal system. What is the secret of these amazing properties of common salt? As scientists from Tufts University (USA) discovered, tadpoles need table salt for the process of restoring a severed or bitten off tail. If you sprinkle it on a wound, the tail grows faster even if scar tissue (scar) has already formed. In the presence of salt, the amputated tail grows back, and the absence of sodium ions blocks this process. Of course, it should be recommended to refrain from uncontrolled consumption of salt, in the hope of speeding up the healing process. Numerous studies clearly demonstrate the harm that excessive salt intake causes to the body. Apparently, to start and accelerate the regeneration process, sodium ions must enter the damaged areas in other ways.

Speaking of modern regenerative medicine, there are usually two main areas. The adherents of the first way are engaged in the cultivation of organs and tissues separately from the patient or on the patient himself, but in a different place (for example, on the back), with their further transplantation into the damaged area. The initial stage in the development of this direction can be considered the solution of the skin issue. Traditionally, new skin tissue was taken from patients' whiskers or corpses, but today skin can be grown in enormous quantities. The raw material of the waste skin is taken from newborn babies. If a baby boy is circumcised, then a huge amount of living tissue can be made from this piece. It is imperative to take the skin for growing newborns, the cells should be as young as possible. A logical question may arise here: why is it so important? The fact is that in order to duplicate DNA during cell division, the enzymes of higher organisms occupied by these enzymes require specially arranged end sections of chromosomes, telomeres. It is to them that the RNA primer is attached, with which the synthesis of the second strand begins on each of the strands of the DNA double helix. However, in this case, the second strand turns out to be shorter than the first by the region that was occupied by the RNA priming. The telomere is shortened until it becomes so small that the primer RNA can no longer attach itself, and the cycles of cell division stop. In other words, the younger the cell, the more divisions will occur before the very possibility of these divisions disappears. In particular, as early as 1961, the American gerontologist L. Hayflick established that "in a test tube" skin cells - fibroblasts - can divide no more than 50 times. From the same foreskin, 6 football fields of skin tissue can be grown (approximate area - 42840 square meters).

Later, a special plastic was developed that is biodegradable. An implant was made from it on the back of a mouse: a plastic frame molded in the shape of a human ear, covered with living cells. During the growth process, the cells adhere to the fibers and take the required shape. Over time, cells begin to dominate and form new tissue (eg, pinna cartilage). Another variant of this method: an implant on the patient's back, which is a frame of the required shape, is seeded with stem cells of a certain tissue. After a while, this fragment is removed from the back and implanted into place.

In the case of internal organs, consisting of several layers of cells of different types, it is necessary to use slightly different methods. The first internal organ was grown and subsequently successfully implanted in the bladder. This is an organ undergoing tremendous mechanical stress: about 40 thousand liters of urine passes through the bladder during life. It consists of three layers: external - connective tissue, middle - muscle, internal - mucous membrane. A full bladder contains approximately 1 liter of urine and is shaped like an inflated balloon. For its cultivation, a frame of a complete bladder was made, on which living cells were seeded layer by layer. It was the first organ to be grown entirely from living tissue.

The same plastic mentioned above was used to repair the damaged spinal cord in laboratory mice. The principle here was the same: plastic fibers were rolled up and embryonic nerve cells were inoculated onto it. As a result, the gap was closed with new tissue, and all motor functions were completely restored. A fairly complete overview is given in the BBC documentary Superman. Self-healing ".

In fairness, we note that the very fact of the possibility of complete restoration of motor functions after severe injuries, up to a complete break of the spinal cord, in addition to single enthusiasts, like V.I. Dikul, was proved by Russian scientists. They also proposed an effective method for the rehabilitation of such people. Despite the fantastic nature of such a statement, I would like to note that analyzing the statements of the leading figures of scientific thought, we can conclude that there are no axioms in science and there can be no axioms, there are only theories that can always be changed or refuted. If the theory contradicts the facts, then the theory is erroneous, and it must be changed. This simple truth, unfortunately, is very often ignored, and the basic principle of science: "Doubt everything" - acquires a purely one-sided character - only in relation to the new. As a result, the latest techniques, which can help thousands and hundreds of thousands of people, are forced to break through a blank wall for years: "This is impossible, because it is impossible in principle." To illustrate the above and to show how far and how long ago science has gone, I will cite a small excerpt from the book of N.P. Bekhtereva "The magic of the brain and the labyrinths of life", one of those specialists who stood at the origins of the development of this method. “In front of me on a gurney lay a blue-eyed guy of 18-20 years old (Ch-ko), a mass of dark brown, almost black hair. “Bend your leg, well, pull it up. Now - straighten up. Another, - commanded the leader of the spinal cord stimulation group, an informal leader. How difficult, how slowly the legs moved! What a tremendous stress it cost the patient! We all wanted to help so much! Still, the legs moved, moved by order: the doctor, the patient himself - it does not matter, it is important - by order. Ana operations spinal cord in the area D9-D11 literally scooped out with spoons. After the Afghan bullet that went through the patient's spinal cord, it was a mess. Afghanistan has made the young handsome man an embittered beast. Still, after the stimulation carried out according to the method proposed by the same informal leader S.V. Medvedev, much has changed in visceral functions.

And what is not allowed? It is impossible to give up on the sick just because the textbooks have not yet included everything that specialists can today. The same doctors who saw the patient and saw everything, were surprised: "Well, have mercy, comrades scientists, of course, there is science, but after all, a complete break of the spinal cord, why can you say ?!" Like this. Have seen and have not seen. There is a scientific film, everything is filmed.

The sooner stimulation begins after brain damage, the more likely the effect is. However, even in cases of long-standing injuries, a lot can be learned and done.

In another patient, the electrodes were inserted upward and downward in relation to the break in the spinal cord. The injury was long-standing, none of us was surprised that the electromyelogram (electrical activity of the spinal cord) of the electrodes below the break was not recorded, the lines were completely straight, as if the device were not turned on. Iv suddenly (!) - no, not quite suddenly, but it looks like “suddenly”, since it happened after several sessions of electrical stimulation, - the electromyelogram of the electrodes below the full, long (6 years) break began to appear, characteristics of electrical activity above the break! This coincided with a clinical improvement in the state of pelvic functions, which, of course, greatly pleased not only the doctors, but also the patient, who was psychologically and physically well adapted to his tragic present and future. It was hard to count on more. The muscles of the legs atrophied, the patient moved on a gurney, his hands took everything they could. But here, in the developing positive and negative events, the matter has not been without changes in the cerebrospinal fluid. Taken sick from the area below the break, it poisoned cells in culture, was cytotoxic. After stimulation, the cytotoxicity disappeared. What happened to the spinal cord below the break before stimulation? Judging by the above animation, he (the brain) did not die. Rather, he slept, but slept as if under anesthesia of toxins, slept in a "dead" sleep - there was no activity of wakefulness, no activity of sleep in the electroencephalogram. "

In the same direction there are more exotic ways, like a three-dimensional bioprinter created in Australia, which already prints skin, and in the near future, according to the assurances of the developers, will be able to print entire organs. Its work is based on the same principle as in the described case of creating a bladder: sowing living cells layer by layer.

The second direction of regenerative medicine can be roughly described with one phrase: “Why grow a new one, if you can fix the old?”. The main task of the adherents of this direction is the restoration of damaged areas by the forces of the organism itself, using its reserves, hidden capabilities (it is worth recalling the beginning of this article) and certain external interventions, mainly in the form of supplying additional resources of construction material for reparation.

There are also a large number of possible options. To begin with, it should be noted that according to some estimates, every organ from birth has a reserve of about 30% of stem cells, which are consumed during life. In accordance with this, according to some gerontologists, the species limit of human life is 110-120 years. Consequently, the biological reserve of a person's life is 30-40 years old, taking into account Russian realities, these figures can be increased to 50-60 years. Another question is that modern living conditions do not contribute to this: extremely deplorable, and every year more and more deteriorating state of ecology; strong, and more importantly, constant stress; huge mental, intellectual and physical stress; the depressing state of local medicine, in particular Russian; the focus of pharmaceuticals is not on helping people, but obtaining super-profits and much more, completely wear out the human body by the time when, in theory, the very heyday of our forces and opportunities should come. However, this reserve can be of great help in recovering from injuries and treating serious illnesses, especially in infants.

Evan Snyder, a neurologist at the Boston Children's Hospital (USA), has been studying the process of recovery of children and infants after various brain injuries for a long time. As a result of his research, he noted the most powerful possibilities for healing the nervous tissues of his young patients. For example, consider the case of an eight-month-old infant who had a massive stroke. Already three weeks after the incident, he had only a slight weakness of the left limbs, and after three months - a complete absence of any pathologies was recorded. Specific cells discovered by Snyder in the study of brain tissue were called neural stem cells or embryonic brain cells (ECM). Subsequently, successful experiments were carried out on the introduction of ECM in mice suffering from tremors. After the injections, the cells spread throughout the brain tissue and complete healing began.

More recently, in the United States, at the Institute of Regenerative Medicine, North Carolina, a team of researchers led by Jerimi Laurence, managed to make the heart of a mouse that died 4 days earlier. Other scientists, in different countries around the world, are trying, and at times very successfully, to start the mechanisms of regeneration with the help of cells secreted from a cancerous tumor. It should be noted here that the telomeres already mentioned above in sexual Iraqi cells are not shortened during division (to be more precise, the point here is in a special enzyme - telomerase, which builds shortened telomeres), which makes them practically immortal. Therefore, such an unexpected turn in the history of sleep diseases has an absolutely rational beginning (this was mentioned in the weekly analytical program "In the center of events" on the state TV Center TV channel).

Separately, we will highlight the creation of hemobanks for the collection of newborn cord blood, which is one of the most promising sources of stem cells. It is known that cord blood is rich in hematopoietic stem cells (HSC). A characteristic feature of SCs obtained from umbilical cord blood is that they are much more similar than that of adult SCs to cells from embryonic tissues in terms of such parameters as biological age and ability to reproduce. Umbilical cord blood obtained from the placenta immediately after childbirth is rich in SCs with greater proliferative capabilities than cells obtained from bone marrow or peripheral blood. Like any blood product, cord blood stem cells require an infrastructure to collect, store, and establish their suitability for transplantation. The umbilical cord is clamped 30 seconds after the baby is born, the placenta and umbilical cord are separated, and the umbilical cord blood is collected in a special bag. The sample must be at least 40ml to be usable. The blood is HLA typed and cultured. Immature human umbilical cord blood cells with a high ability to proliferate, multiply outside the body and survive after transplantation can be stored frozen for more than 45 years, then after thawing they are more likely to remain effective in clinical transplantation. Cord blood banks exist all over the world, only in the USA there are more than 30 of them and there are many more private banks. The US National Institutes of Health is sponsoring the Cord Blood Transplant Study Program. The New York Blood Center has a placental blood program and the National Bone Marrow Donor Registry has its research program.

Mainly, this direction is actively developing in the United States, Western Europe, Japan and Australia. In Russia, this is only gaining momentum, the most famous is the hemobank of the Institute of General Genetics (Moscow). Each year the number of transplants increases, and about a third of patients are now adults. About two thirds of transplants are performed in patients with leukemia, and about a quarter - in patients with genetic diseases. Private cord blood banks offer their services to married couples who are expecting a baby. They save the cord blood for future use by the donor or family members. Public cord blood banks provide transplant resources from unrelated donors. Umbilical cord blood and mother's blood are typed for HLA antigens, checked for the absence of infectious diseases, the blood group is determined and this information is stored in the history of the mother's and family's illness.

Currently, active research is being carried out in the field of multiplication of stem cells contained in a unit of umbilical cord blood, which will allow it to be used for larger patients and will lead to faster engraftment of stem cells. Reproduction of umbilical cord blood SC occurs with the use of growth factors and nutrition. Developed by ViaCell Inc. The technology, called Selective Amplification, makes it possible to increase the population of umbilical cord blood CK by an average of 43 times. Scientists from ViaCell and the University of Duesseldorf (University of Duesseldorf) described a new, truly pluripotent population of human umbilical cord blood cells, which they called USSCs - unrestricted somatic stem cells - unrestricted somatic stem cells (Kogler et al 2004). Both in vitro and in vivo, USSCs showed homogeneous differentiation of osteoblasts, chondroblasts, adipocytes and neurons expressing neurofilaments, sodium channel proteins, and various neurotransmitter phenotypes. Although these cells have not yet been used in human cell therapy, cord blood USSCs can repair a variety of organs, including the brain, bone, cartilage, liver and heart.

Another important area of ​​research is the study of the ability of umbilical cord blood SCs to differentiate into cells of various tissues, in addition to hematopoietic, and the establishment of the corresponding SC lines. Researchers at the University of South Florida (USF, Tampa, FL) used retinoic acid to induce cord blood SCs to differentiate extra-neural cells, as demonstrated at the genetic level by DNA analysis. These results showed the possibility of using these cells for the treatment of neurodegenerative diseases. Umbilical cord blood for this work was provided by the child's parents; it was processed by the state-of-the-art CRYO-CELL laboratory and the frozen cells were donated to the USF scientist. Umbilical cord blood has proven to be a source of much more diverse progenitor cells than previously thought. It can be used to treat neurodegenerative diseases, including in combination with gene therapy, trauma and genetic diseases. In the near future, it will be possible, at the birth of children with genetic defects, to collect their umbilical cord blood, use genetic engineering to correct the defect and return this blood to the child.

In addition to the umbilical cord blood itself, it is possible to use the perivascular umbilical cord cells as a source of mesenchymal stem cells. Scientists from the Institute of Biomaterialis and Biomedical Engineering of the University of Toronto (Toronto, Canada) have found that the jelly-like connective tissue surrounding umbilical cord blood vessels is rich in mesenchymal precursor stem cells and can be used to produce in large quantities in a short time. Perivascular (surrounding vessels) cells are often discarded because the focus is usually on cord blood, in which mesenchymal SCs occur at a rate of only one in 200 million. But this source of progenitor cells, allowing them to proliferate, could greatly improve bone marrow transplants.

In parallel, research is underway on the already found and the search for new ways to obtain adult human SC. These include: milk teeth, brain, mammary glands, fat, liver, pancreas, skin, spleen, or more exotic source - neural cross SC from adult hair follicles. Each of these sources has advantages and disadvantages.

While debates continue about the ethical and therapeutic possibilities of embryonic and adult SCs, a third group of cells was discovered that play a key role in the development of an organism capable of differentiating into cells of all major tissue types. VENT (ventrally emigrating neural tube) cells are unique multipotent cells that detach from the neural tube early in embryonic development after the tube closes and forms the brain (Dickinson et al 2004). VENT cells then move along nerve pathways, eventually ending up in front of the nerves and scattering throughout the body. They move together with cranial nerves to certain tissues and are scattered in these tissues, differentiating into cells of the main four types of tissues - nervous, muscular, connective and epithelium. If VENT cells play a role in the formation of all tissues, perhaps primarily in the formation of connections of the central nervous system with other tissues - taking into account how these cells move in front of the nerves, as if showing them the way. Nerves can be guided by certain signs left after differentiation of VENT cells. This work has been carried out in embryos of chickens, ducks and quails, and it is planned to repeat it in a mouse model, allowing detailed genetic studies. These cells can be used to isolate human cell lines.

Nanomedicine is another advanced and most promising area. Despite the fact that politicians turned their close attention to everything that has a particle "nano" in their names, only a few years ago, this direction has appeared quite a long time ago and certain successes have already been achieved. Most experts believe that these methods will become fundamental in the 21st century. The US National Institutes of Health has ranked nanomedicine as the top five priority areas of medical development in the 21st century, and the US National Cancer Institute is going to apply the advances in nanomedicine in the treatment of cancer. Robert Freytos (USA), one of the founders of the theory of nanomedicine, gives the following definition: “Nanomedicine is the science and technology of diagnosis, treatment and prevention of diseases and traumatism, pain reduction, as well as preservation and improvement of human health using molecular technical means and scientific knowledge to the molecular structure of the human body ”. Eric Drexler, a classic in the field of nanotechnology development and prediction, calls the basic tenets of nanomedicine:

1) do not injure tissue mechanically;

2) do not infect healthy cells;

3) do not cause side effects;

4) medications must independently:

Feel;

To plan;

Act.

The most exotic option is the so-called nanorobots. Among the projects of future medical nanorobots, there is already an internal classification into macrophagocytes, respirocytes, clottocytes, vasculoids and others. All of them are in fact artificial cells, mainly immunity or human blood. Accordingly, their functional purpose directly depends on which cells they replace. In addition to medical nanorobots, which so far exist only in the heads of scientists and individual projects, a number of technologies for the nanomedical industry have already been created in the world. These include: targeted delivery of drugs to sick cells, diagnostics of diseases using quantum dots, laboratories on a chip, new bactericidal agents.

As an example, we will give the development of Israeli scientists in the field of the treatment of autoimmune diseases. The object of their research was the protein matrix metallopeptidase 9 (MMP9), which is involved in the formation and maintenance of the extracellular matrix - tissue structures that serve as a framework on which cells develop. This matrix provides and transport of various chemicals - from nutrients to signaling molecules. It stimulates the growth and proliferation of cells at the site of injury. But the proteins that form it, and above all MMP9, getting out of control of the proteins inhibiting their activity - endogenous inhibitors of metalloproteinases (TIMPS) - can become the reasons for the development of some autoimmune disorders.

Researchers have tackled the question of how you can "tame" these proteins in order to suppress autoimmune processes right at the source. Until now, in solving this problem, scientists have concentrated on finding chemicals that selectively block the work of MMPS. However, this approach has serious limitations and severe side effects - the Irit Sagi biologists decided to tackle the blue side problem. They decided to synthesize a molecule that, when introduced into the body, would stimulate the immune system to produce antibodies similar to TIMPS proteins. This significantly more subtle approach provides the highest accuracy: antibodies will attack MMPS many orders of magnitude more selectively and more efficiently than any chemical compound.

And the scientists succeeded: they synthesized an artificial analogue of the active site of the MMPS9 protein: a zinc ion coordinated by three histidine residues. Injection of it to laboratory mice led to the production of antibodies that act in exactly the same manner as TIMPS proteins work: by blocking the entry of a vacant site.

The world is witnessing a boom in investments in the industry. Most of the investment in R&D is in the US, EU, Japan and China. The number of scientific publications, patents and journals is constantly growing. There are forecasts for the creation by 2015 of goods and services for $ 1 trillion, including the formation of up to 2 million jobs.

In Russia, the Ministry of Education and Science has created an Interdepartmental Scientific and Technical Council on the Problem of Nanotechnology and Anomaterials, whose activities are aimed at maintaining technological parity in the future world. For the development of nanotechnology in general and anomedicine in particular. The adoption of a federal target program for their development is being prepared. This program will include the training of a number of specialists in the long term.

According to various estimates, the achievements of nanomedicine will become available only in 40-50 years. Eric Drexler himself calls the figure 20-30 years old. But given the scale of the work in this area and the amount of money invested outside, more and more analysts are shifting their initial estimates by 10-15 years towards a decrease.

The most interesting thing is that such medicines already exist, they were created more than 30 years ago in the USSR. The impetus for research in this direction was the discovery of the effect of premature aging of the body, which was widely observed by displaced persons, especially in missile-strategic troops, crews of nuclear submarine missile carriers, and combat aviation pilots. This effect is expressed in the premature destruction of the immune, endocrine, nervous, cardiovascular, reproductive systems, vision. It is based on the process of suppressing protein synthesis. The main question facing Soviet scientists: "How to restore a full-fledged synthesis?" Initially, the drug "Timolin" was created, made on the basis of peptides isolated from the thymus of young animals. It was the world's first immune system drug. Here we see the same principle that was laid on the basis of the process of obtaining insulin, in the early stages of the development of methods for treating diabetes mellitus. But the researchers of the Department of Structural Biology of the Institute of Bioorganic Chemistry, headed by Vladimir Khavinson, did not stop there. In the nuclear magnetic resonance laboratory, the spatial and chemical structures of the peptide molecule from the thymus were determined. Based on the information received, a method was developed for the synthesis of short peptides that have desired properties similar to natural ones. The result is the creation of a series of drugs called cytogens (other possible names: bioregulators or synthetic peptides; indicated in the table).

List of cytogens

Name	Structure	Direction of action
		Immune system and regeneration process
Cortagen		central nervous system
Cardiogen		The cardiovascular system
		Digestive system
Epitalon		Endocrine system
Prostamax		Genitourinary system
Pankragen		Pancreas
Bronchogen		Broncho-pulmonary system

When the St. Petersburg Institute of Bioregulation and Gerontology conducted experiments on mice and rats (the intake of cytogens began in the second half of life), an increase in life was observed by 30-40%. Subsequently, a survey and continuous monitoring of the health status of 300 elderly people, residents of Kiev and St. Petersburg, who took cytogens in courses twice a year, were carried out. The data on their well-being were checked against the statistics for the region. They experienced a 2-fold decrease in mortality and an overall improvement in well-being and quality of life. In general, over 20 years of using bioregulators, more than 15 million people have gone through therapeutic measures. The effectiveness of the use of synthetic peptides was consistently high, and, more importantly, not a single case of an adverse or allergic reaction was recorded. The laboratory received the Prizes of the Council of Ministers of the USSR, the authors - extraordinary scientific titles, degrees of doctors of science and carte blanche in scientific work. All the work done was protected by patents, both in the USSR and abroad. The results obtained by Soviet scientists published in foreign scientific journals contradicted the globally recognized norms and limits, which inevitably raised doubts among experts. Tests at the US National Institute of Aging have confirmed the high efficacy of cytogens. In the experiments, an increase in the number of cell divisions was observed with the addition of synthetic peptides compared to the control by 42.5%. Why this line of drugs has not yet been introduced to the international sales market, given the lack of foreign analogues, and this priority is temporary, a big question. Perhaps it is worth asking the management of RosNano, which currently oversees all developments in the field of nanotechnology. You can learn more about these developments in the documentary film “Insight. Nanomedicine and the human species limit "Vladislav Bykov, Prosvet film studio, Russia, 2009.

Summing up, we can make sure that human regeneration is a reality today. A lot of data has already been obtained, destroying the ingrained stereotypes that have become established in public opinion. Many different techniques have been developed that provide healing from diseases that were previously considered incurable due to their degenerative properties, and a successful and complete restoration of damaged or even completely lost organs and tissues. The "polishing" of the old and the search for new and new ways and methods of solving the most complex problems of regenerative medicine is constantly being carried out. Everything that has already been developed now sometimes amazes our imagination, sweeping away all our usual ideas about the world, onas, on our capabilities. At the same time, it is worth realizing that what is described in this article is only a small part of the scientific knowledge gained at this moment. The work is carried out constantly, and it is quite possible that any facts given here, at the time of publication of the article, will already be outdated or completely irrelevant and even erroneous, as was often the case in the history of science: what at some point was considered immutable truth, a year later it could be a delusion. In any case, the facts given in the article inspire hope for a bright, happy future.

Bibliography

1. Popular mechanics [Electronic resource]: electronic version, 2002-2011 - Access mode: http://www.popmech.ru/ (November 20, 2011 - February 15, 2012).
2. Website of the National Institutes of Health (NIH), USA [Electronic resource]: official website of the US NIH, 2011 - Access mode: http://stemcells.nih.gov/info/health/asp. (November 20, 2011 - February 15, 2012).
3. Knowledge base on human biology [Electronic resource]: Development and implementation of knowledge base: Doctor of Biological Sciences, Professor Aleksandrov A.A., 2004-2011 - Access mode: http://humbio.ru/ (November 20, 2011 - February 15, 2012) ...
4. Center for Biomedical Technologies [Electronic resource]: official. Site - M., 2005. - Access mode: http://www.cmbt.su/eng/about/ (November 20, 2011 - February 15, 2012).
5. 60 exercises by Valentin Dikul + Methods for activating human internal reserves = your 100% health / Ivan Kuznetsov - M .: AST; SPb .: Sova, 2009 .-- 160 p.
6. Science and Life: monthly popular science journal, 2011. - №4. - S. 69.
7. Commercial biotechnology [Electronic resource]: Internet magazine - Access mode: http://www.cbio.ru/ (November 20, 2011 - February 15, 2012).
8. Foundation "Eternal Youth" [Electronic resource]: popular science portal, 2009 - Access mode: http://www.vechnayamolodost.ru/ (November 20, 2011 - February 15, 2012).
9. The magic of the brain and the labyrinths of life / N.P. Ankylosing spondylitis. - 2nd ed., Add. - M .: AST; Saint Petersburg: Sova, 2009 .-- 383 p.
10. Nanotechnology and nanomaterials [Electronic resource]: federal Internet portal, 2011 - Access mode: http://www.portalnano.ru/read/tezaurus/definitions/nanomedicine (November 20, 2011 - February 15, 2012).

Bibliographic reference

Badertdinov R.R. HUMAN REGENERATION - THE REALITY OF OUR DAYS // Successes of modern natural science. - 2012. - No. 7. - P. 8-18;
URL: http://natural-sciences.ru/ru/article/view?id=30279 (date accessed: 23.08. We bring to your attention the journals published by the "Academy of Natural Sciences"

Surprisingly, if the lizard's tail falls off, then the missing part will re-form from the remaining one. In some cases, reparative regeneration is so perfect that the entire multicellular organism is restored from only a small piece of tissue. Our body spontaneously loses cells from the skin surface and replaces them with newly formed ones. This is precisely because of the regeneration.

Regeneration types

Reparative regeneration is a natural ability of all living organisms. It is used to replace worn-out parts, renew damaged and lost fragments, or recreate a body from a small area during the post-embryonic life of an organism. Regeneration is a process that includes growth, morphogenesis, and differentiation. Today, all types and types of reparative regeneration are actively used in medicine. This process occurs not only in humans, but also in animals. Regeneration is divided into two types:

• physiological;
• reparative.

There is a permanent loss of many structures in our body due to wear and tear. The replacement of these cells is due to physiological regeneration. An example of such a process is the renewal of red blood cells. Worn skin cells are constantly being replaced with new ones.

Reparative regeneration is the process of restoring lost or damaged organs and body parts. In this type, tissues are formed by expanding adjacent fragments.

• Regeneration of the limbs in the salamander.
• Restoration of the lost lizard tail.
• Wound healing.
• Replacement of damaged cells.

Varieties of reparative regeneration. Morphallaxis and epimorphosis

There are different types of reparative regeneration. You can find more detailed information about them in our article. Regeneration of the epimorphic type includes the differentiation of adult structures in order to form an undifferentiated mass of cells. It is with this process that the restoration of a deleted fragment is connected. An example of epimorphosis is limb regeneration in amphibians. In the morphallaxis type, regeneration occurs mainly due to the rearrangement of already existing tissues and the restoration of boundaries. An example of such a process is the formation of a hydra from a small fragment of its body.

Reparative regeneration and its forms

Recovery occurs due to the proliferation of adjacent tissues, which fill young cells with a defect. Subsequently, full-fledged mature fragments are formed from them. These forms of reparative regeneration are called recovery.

There are two options for this process:

• The loss is compensated for with a cloth of the same type.
• The defect is replaced with a new cloth. A scar is formed.

Bone tissue regeneration. New method

In the modern medical world, reparative bone regeneration is a reality. This technique is most commonly used in bone graft transplant surgery. It is worth noting that it is incredibly difficult to collect enough material for such a procedure. Fortunately, a new surgical method for repairing damaged bones has emerged.

Through biomimicry, researchers have developed a new method for restoring bone structure. Its main purpose is to use sea sponge corals as skeletons or frames for bone tissue. Thanks to this, the damaged fragments will be able to repair themselves on their own. Corals are ideal for this type of surgery because they integrate easily into existing bones. Their structure also coincides in terms of porosity and composition.

Bone regeneration process with coral

In order to recover using the new method, surgeons must prepare coral or sea sponges. They also need to select substances such as stromal or bone marrow that can become any other adamantoblast in the body. Reparative tissue regeneration is a rather laborious process. During the operation, sponges and cells are inserted into the section of the damaged bone.

Over time, bone fragments are either repaired, or the stem adamantoblasts expand existing tissue. Once the bone is healed, the coral or becomes part of it. This is due to their similarity in structure and composition. Reparative regeneration and methods of its implementation are being studied by specialists from all over the world. It is thanks to this process that you can cope with some of the acquired deficiencies of the body.

Restoration of the epithelium

Reparative regeneration methods play an important role in the life of any living organism. The transitional epithelium is a stratified layer that is characteristic of the urinary organs such as the bladder and kidneys. They are most susceptible to sprains. It is in them that tight contacts are located between the cells, which prevent the penetration of fluid through the organ wall. The adamantoblasts of the urinary tract quickly wear out and weaken. Reparative regeneration of the epithelium occurs due to the content of stem cells in the organs. It is they who retain the ability to divide throughout the entire life cycle. Over time, the update process deteriorates significantly. Associated with this are numerous diseases that occur in many with age.

Mechanisms of reparative regeneration of the skin. Their effect on body recovery after burn injuries

Burns are known to be the most common injury among children and adults. Today, the topic of such injuries is extremely popular. It is no secret that burn injuries can not only leave a scar on the body, but also cause surgical intervention. To date, there is no such procedure that would completely get rid of the resulting scar. This is due to the fact that the mechanisms of reparative regeneration are not fully understood.

There are three degrees of burn injury. More than 4 million people are known to suffer from skin damage caused by exposure to steam, hot water or a chemical. It is worth noting that the scarred skin does not match the one it is replacing. It also differs in its functions. The newly formed tissue is weaker. Today, experts are actively studying the mechanisms of reparative regeneration. They believe that they will soon be able to completely rid patients of burn scars.

The level of reparative bone tissue regeneration. Optimal process conditions

Reparative bone tissue regeneration and its level are determined by the degree of damage in the fracture area. The more microcracks and injuries, the slower the formation of callus will proceed. It is for this reason that specialists give preference to methods of treatment that are not associated with the infliction of additional damage. The most optimal conditions for reparative regeneration in bone fragments are the immobility of the fragments and delayed distraction. If they are absent, connective fibers are formed at the fracture site, which subsequently form

Pathological regeneration

Physical and reparative regeneration plays an important role in our life. It is no secret that for some, this process may be slowed down. What is the reason for this? You can find out this and much more in our article.

Pathological regeneration is a violation of recovery processes. There are two types of such recovery - hyper-regeneration and hyporegeneration. The first process of new tissue formation is accelerated, and the second is slowed down. These two types are a violation of regeneration.

The first signs of pathological regeneration are the formation of long healing of injuries. Such processes arise as a consequence of the violation of local conditions.

How to speed up the process of physiological and reparative regeneration

Physiological and reparative regeneration plays an important role in the life of every living creature. Examples of such a process are known to absolutely everyone. It's no secret that in some patients, injuries take a long time to heal. Any living organism should have a complete diet, which includes a variety of vitamins, trace elements and nutrients. With a lack of nutrition, an energy deficit occurs, and trophic processes are disrupted. As a rule, patients develop this or that pathology.

To speed up the regeneration process, it is necessary first of all to remove dead tissue and take into account other factors that may affect recovery. These include stress, infections, dentures, vitamin deficiencies, and more.

To speed up the regeneration process, a specialist can prescribe a vitamin complex, anabolic agents and biogenic stimulants. In home medicine, sea buckthorn oil, carotene, as well as juices, tinctures and decoctions of medicinal herbs are actively used.

Shilajit to accelerate regeneration

Reparative regeneration refers to the complete or partial restoration of damaged tissues and organs. Does such a process accelerate the mummy? What it is?
It is known that the mummy has been used for 3 thousand years. It is a biologically active substance that flows from the crevices of the rocks of the southern mountains. Its deposit is found in more than 10 countries around the world. Shilajit is a sticky mass of dark brown color. The substance is highly soluble in water. Depending on the place of collection, the composition of the mummy may differ. Nevertheless, absolutely each of them contains a vitamin complex, a number of minerals, essential oils and bee venom. All of these components contribute to the rapid healing of wounds and injuries. They also improve the body's response to adverse conditions. Unfortunately, there is no preparation based on mummy to accelerate regeneration, since the substance is difficult to process.

Regeneration in animals. general information

As we said earlier, the regeneration process occurs in absolutely any living organism, including an animal. It is worth noting that the higher it is organized, the worse the recovery goes in its body. In animals, reparative regeneration is the process of reproduction of lost or damaged organs and tissues. The simplest organisms regenerate their bodies only if they have a nucleus. If it is absent, then the lost parts will not be reproduced.

It is believed that siskins can regenerate their limbs. However, this information has not been confirmed. It is known that mammals and birds only regenerate tissues. However, the process is not fully understood.
Nervous and muscle tissue is most easily restored in animals. In most cases, new fragments are formed from the remnants of old ones. In amphibians, a significant increase in regenerating organs was observed. This is also the case with lizards. For example, instead of one tail, two grow.

After conducting a number of studies, scientists have proven that if a lizard is cut off the tail obliquely and touched not one, but two or more spines, then the reptile will grow 2-3 tails. There are also cases when an organ can be restored in an animal not where it was previously located. Surprisingly, through regeneration, an organ can also be recreated that was not previously in the body of this or that creature. This process is called heteromorphosis. All methods of reparative regeneration are extremely important not only for mammals, but also for birds, insects, and also unicellular organisms.

Summing up

Each of us knows that lizards can easily fully restore their tail. Not everyone knows why this is happening. Physiological and reparative regeneration plays an important role in everyone's life. To restore it, you can use both medications and home methods. Shilajit is considered one of the best remedies. It not only accelerates the regeneration process, but improves the general background of the body. Be healthy!

VOLGOGRAD STATE ACADEMY OF PHYSICAL CULTURE

abstract

in biology

on the topic of:

“Regeneration, its types and levels. Conditions affecting the course of recovery processes "

Completed: student group 108

Timofeev D. M

Volgograd 2003

Introduction

1. The concept of regeneration

2. Types of regeneration

3. Conditions affecting the course of recovery processes

Conclusion

Bibliography

Introduction

Regeneration is the renewal of the body's structures in the process of vital activity and the restoration of those structures that have been lost as a result of pathological processes. To a greater extent, regeneration is inherent in plants and invertebrates, to a lesser extent in vertebrates. Regeneration - in medicine - the complete restoration of lost parts.

The phenomena of regeneration have been familiar to people since ancient times. By the end of the 19th century. material has been accumulated that reveals the laws of the regenerative reaction in humans and animals, but the problem of regeneration has been developed especially intensively since the 40s. 20th century

Scientists have long been trying to understand how amphibians - for example, newts and salamanders - regenerate severed tails, limbs, and jaws. Moreover, the damaged heart, eye tissues, and spinal cord are also restored. The method used by amphibians for self-repair became clear when scientists compared the regeneration of mature individuals and embryos. It turns out that in the early stages of development, the cells of the future creature are immature, their fate may well change.

In this essay, the concept will be given and the types of regeneration will be considered, as well as the features of the course of recovery processes.

1. Regeneration concept

REGENERATION(from late Lat. regenera-tio - revival, renewal) in biology, restoration by the body of lost or damaged organs and tissues, as well as restoration of the whole organism from its part. Regeneration is observed in vivo and can also be induced experimentally.

Rregeneration in animals and humans- the formation of new structures to replace those that were removed or died as a result of damage (reparative regeneration) or lost in the course of normal life (physiological regeneration); secondary development caused by the loss of a previously developed organ. A regenerated organ may have the same structure as a distant one, differ from it, or not at all resemble it (atypical regeneration).

The term "regeneration" was proposed in 1712 French. the scientist R. Reaumur, who studied the regeneration of the legs of crayfish. In many invertebrates, it is possible to regenerate a whole organism from a piece of the body. In highly organized animals this is impossible - only individual organs or their parts are regenerated. Regeneration can occur through the growth of tissues on the wound surface, the restructuring of the remaining part of the organ into a new one, or by the growth of the remainder of the organ without changing its shape . The idea of ​​a weakening of the ability to regenerate as the organization of animals increases is erroneous, since the process of regeneration depends not only on the level of organization of the animal, but also on many other factors and is therefore characterized by variability. It is also wrong to say that the ability to regenerate naturally decreases with age; it can also increase in the process of ontogenesis, but in the period of old age its decrease is often observed. Over the past quarter of a century, it has been shown that, although in mammals and humans, entire external organs do not regenerate, their internal organs, as well as muscles, skeleton, and skin, are capable of regeneration, which is studied at the organ, tissue, cellular and subcellular levels. The development of methods for enhancing (stimulating) the weak and restoring the lost ability to regenerate will bring the doctrine of regeneration closer to medicine.

Regeneration in medicine. Distinguish between physiological, reparative and pathological regeneration. In case of injuries and other pathological conditions that are accompanied by massive cell death, tissue restoration is carried out at the expense of reparative(restorative) regeneration. If, in the process of reparative regeneration, the lost part is replaced by an equivalent, specialized tissue, one speaks of complete regeneration (restitution); if non-specialized connective tissue grows at the site of the defect, about incomplete regeneration (healing through scarring). In some cases, with substitution, the function is restored due to the intensive neoplasm of tissue (similar to the dead tissue) in the intact part of the organ. This neoplasm occurs either through enhanced cell multiplication, or through intracellular regeneration — the restoration of subcellular structures with an unchanged number of cells (cardiac muscle, nervous tissue). Age, metabolic features, the state of the nervous and endocrine systems, nutrition, the intensity of blood circulation in the damaged tissue, concomitant diseases can weaken, enhance or qualitatively change the regeneration process. In some cases, this leads to pathological regeneration. Its manifestations: long-term non-healing ulcers, disorders of the fusion of bone fractures, excessive tissue proliferation or the transition of one type of tissue to another. Therapeutic effects on the regeneration process are to stimulate complete and prevent pathological regeneration.

Rplant regeneration can occur at the site of a lost part (restitution) or at another site of the body (reproduction). Spring regeneration of leaves instead of fallen leaves in autumn is a natural regeneration of the reproduction type. Usually, however, regeneration is understood only as the restoration of forcibly rejected parts. With such regeneration, the body primarily uses the main pathways of normal development. Therefore, the regeneration of organs in plants occurs mainly through reproduction: the removed organs are compensated by the development of existing or newly formed metameric structures. So, when cutting off the top of the shoot, lateral shoots develop vigorously. Plants or their parts that do not develop metamerically are easier to regenerate by restitution, just like tissue sites. For example, the wound surface may become covered with the so-called wound peridermis; a wound on a trunk or branch can heal with influxes (calluses). Propagation of plants by cuttings is the simplest case of regeneration, when a whole plant is restored from a small vegetative part.

Regeneration from sections of the root, rhizome or thallus is also widespread. You can grow plants from leaf cuttings, leaf pieces (for example, begonias). Some plants succeeded in regeneration from isolated cells and even from individual isolated protoplasts, and in some species of siphon algae - from small areas of their multinucleated protoplasm. The young age of the plant usually promotes regeneration, but at too early stages of ontogeny, the organ may be unable to regenerate. As a biological device that ensures the healing of wounds, the restoration of accidentally lost organs, and often vegetative reproduction, regeneration is of great importance for plant growing, fruit growing, forestry, ornamental gardening, etc. It also provides material for solving a number of theoretical problems, incl. and developmental problems of the body. Growth substances play an important role in the regeneration processes.

2. Regeneration types

There are two types of regeneration - physiological and reparative.

Physiological regeneration- continuous renewal of structures at the cellular (change of blood cells, epidermis, etc.) and intracellular (renewal of cellular organelles) levels, which ensure the functioning of organs and tissues.

Reparative regeneration- the process of eliminating structural damage after the action of pathogenic factors.

Both types of regeneration are not separate, independent of each other. Thus, reparative regeneration develops on the basis of physiological, that is, on the basis of the same mechanisms, and differs only in a greater intensity of manifestations. Therefore, reparative regeneration should be considered as a normal reaction of the body to damage, characterized by a sharp increase in the physiological mechanisms of reproduction of specific tissue elements of a particular organ.

The importance of regeneration for the body is determined by the fact that on the basis of cellular and intracellular renewal of organs, a wide range of adaptive fluctuations in their functional activity in changing environmental conditions is provided, as well as restoration and compensation of functions disturbed under the influence of various pathogenic factors.

Physiological and reparative regeneration are the structural basis of the whole variety of manifestations of the body's vital activity in health and disease.

The regeneration process unfolds at different levels of organization - systemic, organ, tissue, cellular, intracellular. It is carried out by direct and indirect cell division, renewal of intracellular organelles and their reproduction. Renewal of intracellular structures and their hyperplasia are a universal form of regeneration inherent in all mammalian and human organs without exception. It is expressed either in the form of intracellular regeneration itself, when after the death of a part of the cell, its structure is restored due to the reproduction of the preserved organelles, or in the form of an increase in the number of organelles (compensatory hyperplasia of organelles) in one cell upon death of another.

The restoration of the original mass of an organ after its damage is carried out in various ways. In some cases, the preserved part of the organ remains unchanged or slightly changed, and its missing part grows from the wound surface in the form of a clearly delimited regenerate. This method of restoring a lost part of an organ is called epimorphosis. In other cases, the rest of the organ is rearranged, during which it gradually acquires its original shape and size. This version of the regeneration process is called morphallaxis. More often, epimorphosis and morphallaxis are found in various combinations. Observing an increase in the size of an organ after its damage, we first spoke of its compensatory hypertrophy. Cytological analysis of this process showed that it is based on cell multiplication, that is, a regenerative reaction. In this regard, the process was named "regenerative hypertrophy".

It is generally accepted that reparative regeneration develops after the onset of dystrophic, necrotic and inflammatory changes. This, however, is not always the case. Much more often, immediately after the onset of the action of the pathogenic factor, physiological regeneration is sharply intensified, aimed at compensating for the loss of structures, due to their sudden accelerated consumption or death. At this time, it is essentially a reparative regeneration.

There are two points of view about the sources of regeneration. According to one of them (the theory of reserve cells), there is a proliferation of cambial, immature cellular elements (the so-called stem cells and progenitor cells), which, multiplying and differentiating intensively, make up for the loss of highly differentiated cells of this organ, providing its specific function. Another point of view assumes that the source of regeneration can be highly differentiated cells of an organ, which, under conditions of a pathological process, can be rearranged, lose part of their specific organelles and at the same time acquire the ability to mitotic division with subsequent proliferation and differentiation.

3. Conditions affecting the course of recovery processes

The results of the regeneration process can be different. In some cases, the regeneration ends with the formation of a part identical to the dead one in the form of J, built from the same tissue. In these cases, one speaks of complete regeneration (restitution, or homomorphosis). As a result of regeneration, a completely different organ than the remote one can form, which is referred to as heteromorphosis (for example, the formation of a limb in crustaceans instead of an antennae). There is also an incomplete development of the regenerating organ - hypotype (for example, the appearance of a smaller number of fingers on a limb in a newt). The opposite also happens - the formation of a larger number of limbs than normal, abundant neoplasm of bone tissue at the site of the fracture, etc. (excessive regeneration , or super-regeneration). In some cases, in mammals and humans, as a result of regeneration in the area of ​​damage, not tissue specific to this organ is formed, but connective tissue, which is subsequently scarred. , which is referred to as incomplete regeneration. or restitution. Completion of the recovery process with complete regeneration , or substitution, is largely determined by the preservation or damage to the connective tissue frame of the organ. If only the parenchyma of the organ dies selectively, for example. liver, then its complete regeneration usually occurs ; if the stroma also undergoes necrosis, the process always ends with the formation of a scar. For various reasons (hypovitaminosis, exhaustion, etc.), the course of reparative regeneration can take on a protracted nature, be qualitatively perverted, accompanied by the formation of sluggishly granulating ulcers that do not heal for a long time, the formation of a false joint instead of bone fragments fusion, tissue hyperregeneration, metaplasia, etc. cases speak of pathological regeneration.

The degree and forms of expression of regenerative capacity are not the same in different animals. A number of protozoa, coelenterates, flatworms, nemerteans, annelids, echinoderms, hemichordates, and larval-chordates have the ability to restore from a separate fragment or piece of the body is a whole organism. Many representatives of the same groups of animals are able to restore only large areas of the body (for example, its head or tail ends). Others restore only individual lost organs or part of them (regeneration of amputated limbs, antennae, eyes - in crustaceans; parts of the legs, mantle, head, eyes, tentacles, shells - in mollusks; limbs, tail, eyes, jaws - in tailed amphibians, etc. .). The manifestations of the regenerative ability in highly organized animals, as well as in humans, are distinguished by a significant variety - large parts of internal organs (for example, liver), muscles, bones, skin, etc., as well as individual cells after the death of a part of their cytoplasm and organelles, can be restored.

Due to the fact that higher animals are not able to completely restore an organism or its large parts from small fragments, as one of the important regularities of regenerative capacity in the 19th century. the position was put forward that it decreases as the organization of the animal increases. However, in the process of in-depth development of the problem of regeneration, especially the manifestations of regeneration in mammals and humans, the erroneousness of this position became more and more obvious. Numerous examples indicate that among relatively low-organized animals there are those that are distinguished by a weak regenerative ability (sponges, roundworms), while many relatively highly organized animals (echinoderms, lower chordates) have this ability to a fairly high degree. In addition, among closely related animal species, both good and poorly regenerating ones are often found.

Numerous studies of regenerative processes in mammals and humans, systematically carried out since the middle of the 20th century, also indicate the inconsistency of the idea of ​​a sharp decrease or even complete loss of regenerative capacity as the organization of the animal and the specialization of its tissues increase. The concept of regenerative hypertrophy indicates that the restoration of the original shape of an organ is not the only criterion for the presence of regenerative capacity, and that for the internal organs of mammals an even more important indicator in this regard is their ability to restore their original mass, i.e., the total number of structures that provide a specific function. As a result of electron microscopic studies, ideas about the range of manifestations of the regenerative reaction have radically changed and, in particular, it became obvious that the elementary form of this reaction is not the reproduction of cells, but the restoration and hyperplasia of their ultrastructures. This, in turn, was the basis for referring to the regeneration processes such a phenomenon as cell hypertrophy. It was believed that this process is based on a simple increase in the nucleus and mass of the cytoplasmic colloid. Electron microscopic studies made it possible to establish that cell hypertrophy is a structural process caused by an increase in the number of nuclear and cytoplasmic organelles and, on the basis of this, ensuring the normalization of the specific function of a given organ during the death of one or another of its parts, i.e., in principle, it is a regenerative, restorative process. With the help of electron microscopy, the essence of such a widespread phenomenon as the reversibility of dystrophic changes in organs and tissues was deciphered. It turned out that this is not just normalization of the composition of the colloid of the nucleus and cytoplasm, disturbed as a result of a pathological process, but a much more complex process of normalization of the architectonics of the cell by restoring the structure of damaged organelles and their neoplasms. That. and this phenomenon, which previously stood apart from other general pathological processes, turned out to be a manifestation of the body's regenerative response.

In general, all these data were the basis for a significant expansion of ideas about the role and significance of regeneration processes in the life of the organism, and in particular for the advancement of a fundamentally new position that these processes are related not only to the healing of injuries, but are the basis of the functional activity of organs. ... An important role in the approval of these new ideas about the range and essence of regeneration processes was played by the point of view that the main thing in the regeneration of an organ is not only the achievement of its initial anatomical parameters, but also the normalization of the impaired function, provided by various variants of structural transformations . It is in this fundamentally new light from the structural and functional point of view that the doctrine of regeneration loses its predominantly biological sound (restoration of remote organs) and becomes paramount for solving the main problems of the modern wedge. medicine, in particular the problems of compensation for impaired functions .

These data are convincing that the regenerative capacity in higher animals and, in particular, in humans is characterized by a significant variety of its manifestations. So, in some organs and tissues, for example. in the bone marrow, integumentary epithelium, mucous membranes, bones, physiological regeneration is expressed in the continuous renewal of the cellular composition, and reparative regeneration - in the complete restoration of the tissue defect and reconstruction of its original form by intensive mitotic cell division. In other organs, for example. in the liver, kidneys, pancreas, organs of the endocrine system, lungs, etc., the renewal of the cellular composition occurs relatively slowly, and the elimination of damage and the normalization of impaired functions are provided on the basis of two processes - cell multiplication and the increase in the mass of organelles in preexisting preserved cells, as a result what they undergo hypertrophy and, accordingly, their functional activity increases. It is characteristic that the original form of these organs after damage is most often not restored, a scar is formed at the site of injury, and the replenishment of the lost part occurs due to intact sections, that is, the recovery process proceeds according to the type of regenerative hypertrophy. The internal organs of mammals and humans have enormous potential ability to regenerative hypertrophy, for example, the liver within 3-4 weeks after resection of 70% of its parenchyma for benign tumors, echinococcus, etc. restores the original weight and in full - functional activity. whose cells do not have the ability to mitotic division, structural and functional recovery after damage is achieved exclusively or almost exclusively due to an increase in the mass of organelles in preserved cells and their hypertrophy, i.e., the regenerative ability is expressed only in the form of intracellular regeneration.

In various organs, the variety of manifestations of physiological and reparative regeneration characteristic of mammals and humans is most likely based on the structural and functional features of each of them. For example, the well-pronounced ability to multiply cells, characteristic of the epithelium of the skin and mucous membranes, is associated with its main function - the continuous maintenance of the integrity of the integument on the border with the environment. Also, the peculiarities of the function explain the high ability of the bone marrow for cellular regeneration by the continuous separation of more and more new cells from the total mass into the blood. The epithelial cells lining the villi of the small intestine regenerate according to the cellular type, since for the implementation of enzymatic activity they descend from the villi into the intestinal lumen, and their place is immediately taken by new cells, which in turn are already ready to be rejected just like it was just happened to their predecessors. Restoration of the support function of the bone can only be achieved by cell proliferation, and it is in the area of ​​the fracture, and not in any other place . In a number of other bodies, for example. in the liver, kidneys, lungs, pancreas, adrenal glands, the required amount of work after injury is ensured primarily by the restoration of the original mass, since the main function of these organs is not so much related to maintaining their shape as to a certain number and size of structural units that perform in each of them specific activity - hepatic lobules, alveoli, pancreatic islets, nephrons, etc. In the myocardium and in the central nervous system mitosis was largely or completely replaced by intracellular damage repair mechanisms. In the central nervous system, in particular, the function of, for example, the pyramidal cell (pyramidal neurocyte) of the cerebral cortex is to continuously maintain connections with the surrounding nerve cells and located in various organs. It is provided by the appropriate structure - numerous and varied processes that connect the cell body with various organs and tissues. To change such a cell in the order of physiological or reparative regeneration means changing all of its extremely complex connections both within the nervous system and far in the periphery. Therefore, the characteristic, most expedient and economical way of restoring the disturbed function for the cells of the central nervous system is to enhance the work of cells adjacent to the dead, due to the hyperplasia of their specific ultrastructures, that is, exclusively through intracellular regeneration.

Thus, the evolutionary process in the animal world was characterized not by a gradual weakening of the regenerative ability, but by an increasing variety of its manifestations. At the same time, the regenerative capacity in each specific organ took on the form that provided the most effective ways to restore its impaired functions.

The whole variety of manifestations of regenerative ability in mammals and humans is based on two forms of it - cellular and intracellular, which in different organs either combine in various combinations, or exist separately. These seemingly extreme forms of the regeneration process are based on a single phenomenon - hyperplasia of nuclear and cytoplasmic ultrastructures. In one case, this hyperplasia develops in preexisting cells and each of them increases, and in the other, the same number of newly formed ultrastructures is located in divided cells that retain their normal size. As a result, the total number of elementary functioning units (mitochondria, nucleoli, ribosomes, etc.) in both cases turns out to be the same. Therefore, among all these combinations of forms of the regenerative reaction, there are no "worst" and "best", more or less effective; each of them is the most appropriate for the structure and function of a given body and at the same time not suitable for all the others. The modern doctrine of intracellular regenerative and hyperplastic processes testifies to the inconsistency of ideas about the possibility of normalizing the work of pathologically altered organs on the basis of "purely functional tension" of the preserved sections; any, even subtle, functional shifts of the compensatory order are always caused by the corresponding proliferative changes) of nuclear and cytoplasmic ultrastructures.

The efficiency of the regeneration process is largely determined by the conditions in which it takes place. The general condition of the organism is of great importance in this respect. Depletion, hypovitaminosis, innervation disorders, etc. have a significant impact on the course of reparative regeneration, inhibiting it and facilitating the transition to pathological. A significant influence on the intensity of reparative regeneration is exerted by the degree of functional load, the correct dosage of which favors this process. The rate of reparative regeneration is, to a certain extent, determined by age, which is of particular importance in connection with the increase in life expectancy and, accordingly, the number of surgical interventions in persons of older age groups. Usually, significant deviations of the regeneration process are not noted and the severity of the disease and its complications seem to be of greater importance than age-related weakening of the regenerative capacity.

Changes in the general and local conditions in which the regeneration process takes place can lead to both quantitative and qualitative changes. For example, the regeneration of the bones of the cranial vault from the edges of the defect usually does not occur. If, however, this defect is filled with bone sawdust, it is closed with full-fledged bone tissue. The study of various conditions for bone regeneration contributed to a significant improvement in methods for eliminating damage to bone tissue. Changes in the conditions of skeletal muscle reparative regeneration are accompanied by a significant increase and increase in its efficiency. It is carried out due to the formation of the preserved fibers of the muscle kidneys at the ends, the multiplication of free myoblasts, the release of reserve cells - satellites, differentiating into muscle fibers. The most important condition for the complete regeneration of the damaged nerve is the connection of its central end with the peripheral one, along the case of which the newly formed nerve trunk moves. General and local conditions affecting the course of regeneration are always realized only within the framework of the regeneration method that is generally characteristic of a given organ, i.e., so far, no changes in conditions have succeeded in transforming cellular into intracellular regeneration and vice versa.

Numerous factors of endogenous and exogenous nature are involved in the regulation of regeneration processes. The antagonistic effects of various factors on the course of intracellular regenerative and hyperplastic processes have been established. The most studied effect on the regeneration of various hormones. Regulation of the mitotic activity of cells of various organs is carried out by hormones of the adrenal cortex, thyroid gland, gonads, etc. An important role in this regard is played by the so-called. gastrointestinal hormones. Known powerful endogenous regulators of mitotic activity - keylones, prostlandins, their antagonists and other biologically active substances.

Conclusion

An important place in studies of the mechanisms of regulation of regeneration processes is occupied by the study of the role of various parts of the nervous system in their course and outcomes. A new direction in the development of this problem is the study of the immunological regulation of regeneration processes, and in particular the establishment of the fact that lymphocytes carry "regenerative information" that stimulates the proliferative activity of cells of various internal organs. A dosed functional load also has a regulating effect on the course of the regeneration process.

The main problem is that tissue regeneration in humans is very slow. Too slow for really significant damage to be repaired. If this process could be accelerated even a little, then the result would be much as significant.

Knowledge of the mechanisms of regulation of the regenerative capacity of organs and tissues opens up prospects for the development of scientific foundations for the stimulation of reparative regeneration and management of the healing processes.

List of used literature

1. Babaeva A. G. Immunological mechanisms of regulation of recovery processes, M., 1972

2. Brodsky V. Ya. And Uryveva IV Cellular polyploidy, M., 1981;

3. New in the doctrine of regeneration, ed. L. D. Lioznera, M., 1977,

4. Regulatory mechanisms of regeneration, ed. A.N. Studitsky and L.D. Lioznera, M., 1973

5. Sarkisov D.S. Regeneration and its clinical significance, M., 1970

6. Sarkisov D.S. Essays on the structural foundations of homeostasis, M., 1977,

7. Sidorova V. F. Age and regenerative capacity of organs in mammals, M., 1976,

8. Ugolev AM Enteric (intestinal hormonal) system, L., 1978, bibliogr .;

9. Conditions for organ regeneration in mammals, ed. L. D. Lioznera, M., 1972