21/06/2017

Artificially growing organs could save millions human lives. Regular news from the field of regenerative medicine sounds encouraging and promising. It seems that the day is just around the corner when bioengineered tissues and organs will be as accessible as car parts.

Advances in regenerative medicine

Therapy methods using cell technologies have been successfully used in medical practice for many years. Artificial organs and tissues obtained using cell therapy and tissue engineering methods have been created and are successfully used. Practical advances in the field of regenerative biomedicine include the cultivation of cartilage tissues, bladder, urethra, heart valves, trachea, cornea and skin. It has been possible to grow an artificial tooth so far only in the body of a rat, but dentists should think about radically new approaches. A technology for restoring the larynx after surgery to remove it has been developed, and many such operations have already been performed. There are known cases of successful implantation of a trachea grown on a donor matrix from patient cells. Artificial cornea transplantation has been carried out for many years.

Serial production of bioprinters has already been launched, which print layer by layer living tissues and organs of a given three-dimensional shape

The easiest to grow were cartilage tissue and skin. Great progress has been made in growing bones and cartilage on matrices. Next level ranked in terms of complexity blood vessels. At the third level were the bladder and uterus. But this stage has already been passed in 2000–2005, after successful completion a number of operations for transplantation of an artificial bladder and urethra. Tissue implants of the vagina, grown in the laboratory from muscle and epithelial cells of patients, not only successfully took root, forming nerves and blood vessels, but have also been functioning normally for about 10 years.

The most complex organs for biomedicine remain the heart and kidneys, which have complex innervation and a system of blood vessels. Growing a whole artificial liver is still a long way off, but fragments of human liver tissue have already been obtained using a method of growing on a matrix of biodegradable polymers. And although the successes are obvious, replacing vital organs such as the heart or liver with their grown analogues is still a matter of the future, although perhaps not very distant.

Matrices for organs

Non-woven sponge matrices for organs are made from biodegradable polymers of lactic and glycolic acids, polylactone and many other substances. Gel-like matrices also have great prospects, into which, in addition to nutrients, growth factors and other inducers of cell differentiation can be introduced in the form of a three-dimensional mosaic corresponding to the structure of the future organ. And when this organ is formed, the gel dissolves without a trace. To create a frame, polydimethylsiloxane is also used, which can be populated with cells of any tissue.

Basic technology organ growing, or tissue engineering, involves using embryonic stem cells to produce specialized tissues

The next step is lining inner surface polymer by immature cells, which then form the walls of blood vessels. Further, other cells of the desired tissue, as they multiply, will replace the biodegradable matrix. The use of a donor frame, which determines the shape and structure of the organ, is considered promising. In the experiments, the rat's heart was placed in a special solution, with the help of which cells of the cardiac muscle tissue were removed, leaving other tissues untouched. The cleaned scaffold was seeded with new cardiac muscle cells and placed in an environment that simulated conditions in the body. After just four days, the cells had multiplied enough that new tissue began to contract, and after eight days the reconstructed heart was able to pump blood. Using the same method, a new liver was grown on a donor scaffold, which was then transplanted into the body of a rat.

Basic organ culture technology

There is probably not a single biological tissue that modern science has not attempted to synthesize. The basic technology of organ culture, or tissue engineering, is the use of embryonic stem cells to produce specialized tissues. These cells are then placed inside a connective intercellular tissue structure consisting primarily of the protein collagen.

A collagen matrix can be obtained by purifying donor biological tissue from cells or creating it artificially from biodegradable polymers or special ceramics, if we're talking about about bones. In addition to cells, they introduce into the matrix nutrients and growth factors, after which the cells form a whole organ or its fragment. It was possible to grow in a bioreactor muscle tissue with a ready-made circulatory system.

The most complex organs for biomedicine remain the heart and kidneys, which have complex innervation and a system of blood vessels

Human embryonic stem cells were induced to differentiate into myoblasts, fibroblasts and endothelial cells. Growing along the microtubules of the matrix, endothelial cells formed capillary beds, came into contact with fibroblasts and caused them to degenerate into smooth muscle tissue. Fibroblasts release growth factor vascular endothelium, which contributed to the further development of blood vessels. When transplanted into mice and rats, such muscles took root much better than tissue sections consisting of muscle fibers alone.

Organoids

Using three-dimensional cell cultures, it was possible to create a simple but fully functional human liver. In a joint culture of endothelial and mesenchymal cells, when a certain ratio is reached, their self-organization begins and three-dimensional spherical structures are formed, which represent the rudiment of the liver. 48 hours after transplantation of these fragments into the body of mice, connections with blood vessels are established and the implanted parts are able to perform functions characteristic of the liver. Successful experiments were carried out on the implantation of a lung grown on a donor matrix purified from cells into a rat.

By influencing the signaling pathways of induced pluripotent stem cells, it was possible to obtain human lung organoids consisting of epithelial and mesenchymal compartments with structural features, characteristic of lung tissue. Bioengineered submandibular embryos salivary glands, designed in vitro, after transplantation, they are able to develop into a mature gland by forming grape-shaped processes with muscle epithelium and innervation.

3D organoids of the eyeball and retina with photoreceptor cells: rods and cones have been developed. An eyeball was grown from undifferentiated embryonic frog cells and implanted into the eye cavity of a tadpole. One week after surgery there were no symptoms of rejection, and the analysis showed that new eye fully integrated into the nervous system and capable of transmitting nerve impulses.

And in 2000, data on the creation of eyeballs grown from undifferentiated embryonic cells. Growing nerve tissue the most complex due to the variety of types of cells that make it up and their complex spatial organization. However, today there is successful experience in growing mouse adenohypophysis from a cluster of stem cells. A three-dimensional culture of brain cell organoids derived from pluripotent stem cells has been created.

Printed organs

Serial production of bioprinters has already been established, which print living tissues and organs of a given three-dimensional shape layer by layer. The printer is capable of high speed apply living cells to any suitable substrate, which is a thermoreversible gel. At temperatures below 20 °C it is a liquid, and when heated above 32 °C it solidifies. Moreover, printing is carried out “from the customer’s material,” that is, from solutions of living cell cultures grown from the patient’s cells. The cells sprayed by the printer grow together after some time. The thinnest layers of gel give the structure strength, and then the gel can be easily removed with water. However, in order to form a functioning organ containing several types of cells in this way, it is necessary to overcome a number of difficulties. The control mechanism by which dividing cells form correct structures is not yet fully understood. However, it seems that despite the complexity of these problems, they are still solvable and we have every reason to believe in the rapid development of a new type of medicine.

Biosafety of using pluripotent cells

Much is expected from regenerative medicine, and at the same time, the development of this area gives rise to many moral, ethical, medical and regulatory issues. A very important issue is the biosafety of using pluripotent stem cells. We have already learned how to reprogram blood and skin cells using transcription factors into induced pluripotent stem cells. The resulting patient stem cell cultures can subsequently develop into neurons and tissues skin, blood and liver cells. It should be remembered that as an adult healthy body There are no pluripotent cells, but they can arise spontaneously in sarcoma and teratocarcinoma. Accordingly, if pluripotent cells or cells with induced pluripotency are introduced into the body, they can provoke the development malignant tumors. Therefore, complete confidence is necessary that the biomaterial transplanted to the patient does not contain such cells. Technologies are now being developed that make it possible to directly obtain tissue cells of a certain type, bypassing the state of pluripotency.

In the 21st century With the development of new technologies, medicine is obliged to move to a qualitatively new level, which will allow timely “repair” of the body affected by a serious illness or age-related changes. I would like to believe that very soon growing organs directly in the operating room from patient cells will be as easy as flowers in greenhouses. Hope is supported by the fact that tissue growing technologies are already working in medicine and saving people's lives.

Medical scientist at work

For many years, scientists around the world have been working on creating working tissues and organs from cells. The most common practice is to grow new tissues from stem cells. This technology has been developed for many years and is consistently bringing success. But fully ensure required quantity organs is not yet possible, since it is possible to grow an organ for a specific patient only from his stem cells.

Scientists from Great Britain have managed to do something that no one else has managed to do so far - to reprogram cells and grow them into a working organ. This will make it possible in the foreseeable future to provide organs for transplantation to everyone who needs it.

Growing organs from stem cells

Growing organs from stem cells has been familiar to doctors for a long time. Stem cells are the progenitors of all cells in the body. They can replace any damaged cells and are intended to restore the body. Maximum quantity These cells occur in children after birth, and with age their number decreases. Therefore, the body’s ability to heal itself gradually decreases.

The world has already created many fully functioning organs from stem cells, for example, in 2004 in Japan they created capillaries and blood vessels from them. And in 2005, American scientists managed to create brain cells. In 2006, human heart valves were created from stem cells in Switzerland. Also in 2006, liver tissue was created in Britain. To today scientists dealt with almost all tissues of the body, even growing teeth.

A very interesting experiment was carried out in the USA - they grew a new heart on a frame from an old one. The donor heart was cleared of muscle and new muscles were grown from stem cells. This completely eliminates the possibility of donor organ rejection, since it becomes “our own.” By the way, there are suggestions that it will be possible to use a pig’s heart, which is anatomically very similar to a human’s, as a frame.

A new way to grow organs for transplantation (Video)

Main disadvantage existing method growing organs is a necessity for their production of the patient’s own stem cells. Not every patient can have stem cells, and especially not everyone has ready-made frozen cells. But recently, researchers from the University of Edinburgh managed to reprogram the body's cells in such a way that they allowed them to grow the necessary organs. According to forecasts wide application This technology will become possible in about 10 years.

Advances in biology and medicine in modern history significantly extended average duration life and saved the world from the sword of Damocles of many deadly diseases. But not all diseases have been defeated, and a person’s life, especially an active one, still seems too short to us. Will science give us a chance to make the next leap?

New skin A laboratory worker takes out a strip of artificially grown epidermis from a bath. The fabric was created at the Dermatological Institute in Italian city Pomezia, Italy, under the direction of Professor Michele De Luca.

There are reasons for optimism, of course. Nowadays, several directions have emerged in science that may, in the near or distant future, make it possible to transform Homo sapiens into a more durable and reliable thinking construct. The first is the creation of electronic-mechanical “supports” for an ailing body. We are talking about robotic bionic prosthetic limbs that reliably reproduce human locomotor, or even entire exoskeletons that can give the joy of movement to the paralyzed.

Growing nervous tissue is the most difficult due to the variety of types of cells that make it up and their complex spatial organization. However, today there is successful experience in growing mouse adenohypophysis from a cluster of stem cells.

These ingenious products will be complemented by a neuromachine interface, which will allow commands to be read directly from the corresponding parts of the brain. Working prototypes of such devices have already been created, now the main thing is to improve them and gradually reduce their cost.

The second direction can be considered research into genetic and other microbiological processes that cause aging. Knowledge of these processes, perhaps in the future, will make it possible to slow down the decline of the body and prolong active life beyond the century limit, and perhaps further.

The search is being conducted in several directions. One of them is a bionic eye: an electronic camera plus a chip implanted in the retina. There have also been some successes in growing retinas (so far in mice).

And finally, the third direction includes research in the field of creating genuine spare parts for human body- tissues and organs that are structurally and functionally not much different from natural ones and will allow timely “repair” of the body affected by a serious illness or age-related changes. News of new steps in this area comes today almost daily.

Start printing

The basic technology of organ growing, or tissue engineering, is the use of embryonic stem cells to produce specialized cells of a particular tissue, for example, hepatocytes - cells of the parenchyma (internal environment) of the liver. These cells are then placed inside a connective intercellular tissue structure consisting primarily of the protein collagen.

Along with the creation of electronic-mechanical prostheses, a search is underway for a more natural implant that combines grown cardiac muscle tissue with a nanoelectronic control system.

This ensures that the entire volume of the organ being grown is filled with cells. A collagen matrix can be obtained by purifying donor biological tissue from cells or, which is much simpler and more convenient, creating it artificially from biodegradable polymers or special ceramics in the case of bone. In addition to the cells, nutrients and growth factors are introduced into the matrix, after which the cells form a single organ or a kind of “patch” designed to replace the affected part.

True, growing an artificial liver, lung and other vital organs for human transplantation is still unattainable today; in simpler cases this technique is successfully used. There is a known case of transplantation of a grown trachea to a patient, carried out at the Russian Research Center for Surgery named after. B.V. Petrovsky under the guidance of Italian professor P. Macchiarini. In this case, the donor trachea was taken as a basis, which was carefully cleaned of cells. In their place, stem cells taken from bone marrow the patient herself. Growth factors and fragments of the mucous membrane were also placed there - they were also borrowed from the damaged trachea of ​​a woman who had to be saved.

Successful experiments were carried out on the implantation of a lung grown on a donor matrix purified from cells into a rat.

Undifferentiated cells under such conditions gave rise to respiratory epithelial cells. The grown organ was implanted into the patient, and special measures were taken to grow the implant with blood vessels and restore blood circulation.

However, there already exists a method for growing tissues without the use of matrices of artificial or biological origin. The method was embodied in a device known as a bioprinter. Nowadays, bioprinters are “out of the age” of prototypes, and small-scale models are appearing. For example, the Organovo device is capable of printing tissue fragments containing 20 or more cellular layers (including cells of different types), united by intercellular tissue and a network of blood capillaries.

Growing a whole artificial liver is still a long way off, but fragments of human liver tissue have already been obtained by growing on a matrix of biodegradable polymers. Such implants can help restore the affected areas.

Connective tissue and the cells are assembled using the same technology that is used in three-dimensional printing: a moving head, positioned with micron precision in a three-dimensional coordinate network, “spits” droplets containing either cells or collagen and other substances to the desired point. Various manufacturers bioprinters reported that their devices are already capable of printing fragments of the skin of experimental animals, as well as elements renal tissue. Moreover, as a result, it was possible to achieve correct location cells of different types relative to each other. True, the era when printers in clinics will be able to create organs for various purposes and in large volumes will have to wait.

Brain for replacement

The development of the topic of spare parts for humans inevitably leads us to the topic of the most intimate - what makes a person human. Brain replacement is perhaps the most fantastic idea regarding potential immortality. The problem, as you might guess, is that the brain appears to be the most complex material object known to mankind in the universe. And perhaps one of the most incomprehensible. It is known what it consists of, but very little is known about how it works.

New skin. A laboratory worker takes a strip of artificially grown epidermis from the bath. The fabric was created at the Dermatological Institute in Pomezia, Italy, under the direction of Professor Michele De Luca.

Thus, if the brain can be recreated as a collection of neurons establishing connections with each other, we still need to figure out how to place all of it into it. necessary for a person information. Otherwise, at best, we will get an adult with the “gray matter” of a baby. Despite all the super fantastic ultimate goal, science is actively working on the problem of nerve tissue regeneration. In the end, the goal may be more modest - for example, restoring part of the brain destroyed as a result of injury or serious illness.

The problem of artificial regeneration of brain tissue is aggravated by the fact that the brain is highly heterogeneous: it contains many types nerve cells, in particular inhibitory and excitatory neurons and neuroglia (literally “nerve glue”) - a collection of supporting cells of the nervous system. Besides, different types cells are arranged in a certain way in three-dimensional space, and this arrangement must be reproduced.

This is the same case when tissue growing technologies are already working in medicine and saving people’s lives. There are known cases of successful implantation of a trachea grown on a donor cell matrix spinal cord patient.

Nerve chip

In one of the laboratories of the famous Massachusetts Institute of Technology, known for its developments in the field of information technology, they approached the creation of artificial nervous tissue “in a computer way”, using elements of microchip manufacturing technology.

Researchers in Boston took a mixture of nerve cells obtained from the primary rat cortex and applied them to thin sheets of hydrogel. The plates formed a kind of sandwich, and now the task was to isolate from it individual blocks with a given spatial structure. Having received such transparent blocks, scientists intended to study the processes of the formation of neural connections within each of them.

Technology for transplanting a human bladder grown on a collagen matrix from the bladder or small intestine of animal origin, has already been created and has a positive practice of use.

The problem was solved using photolithography. Plastic masks were placed on the hydrogel layers, which allowed light to affect only certain areas, “welding” them together. In this way, it was possible to obtain compositions of cellular material of various sizes and thicknesses. Studying these building blocks could eventually lead to the creation of meaningful pieces of neural tissue for use in implants.

If MIT engineers approach the study and reconstruction of nervous tissue in an engineering style, that is, mechanically forming the necessary structures, then at the RIKEN Center for Developmental Biology in the Japanese city of Kobe, scientists under the leadership of Professor Yoshiki Sasai are groping for another path - evo-devo, the path of developmental evolution. If pluripotent stem cells of an embryo can, when dividing, create self-organizing structures of specialized cells (that is, various organs and tissues), then is it possible, having comprehended the laws of such development, to direct the work of stem cells to create implants with natural forms?

Much progress has been made in growing bones and cartilage on matrices, but restoring the neural tissue of the spinal cord is a matter of the future.

And so main question, to which Japanese biologists intended to find an answer: to what extent does the development of specific cells depend on external factors (for example, on contact with neighboring tissues), and to what extent the program is “hardwired” inside the stem cells themselves. Research has shown that it is possible to grow a given specialized element of the body from an isolated group of stem cells, although external factors play a role - for example, certain chemical inducing signals are needed to force the stem cells to develop, say, exactly like nervous tissue. And for this you will not need any supporting structures that will have to be filled with cells - the forms will arise themselves in the process of development, during cell division.

In a new body

The question of a brain transplant, since the brain is the seat of intelligence and the human “I” itself, essentially does not make sense, since if the brain is destroyed, then it is impossible to recreate the personality (unless over time they learn to make “backup copies” of consciousness). The only thing that could make sense is a head transplant, or rather, a body transplant to a head that has problems with its body. However, if it is impossible at the modern level of medicine to restore the spinal cord, the body with a new head will remain paralyzed. True, as tissue engineering develops, it is possible that the nervous tissue of the spinal cord can be restored using stem cells. During the operation, the brain will have to be rapidly cooled to prevent the death of neurons.

Using Sasai's patented method, the Japanese managed to grow three-dimensional structures of nervous tissue, the first of which was the retina of the eye (the so-called optic cup), obtained from embryonic stem cells of mice, which consisted of functionally different types of cells. They were located as nature dictates. The next achievement was the adenohypophysis, which not only replicates the structure of the natural one, but also releases the necessary hormones when transplanted into a mouse.

Of course, fully functional implants of nervous tissue, and even more so parts of the human brain, are still very, very far away. However, the successes of artificial tissue regeneration using developmental evolution technologies indicate the path that all regenerative medicine will follow: from “smart” prostheses - to composite implants, in which ready-made spatial structures are “sprouted” with cellular material, and further - to the growing of spare parts for humans according to the same laws by which they develop in natural conditions.

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

What are stem cells

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

Where are stem cells found?

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

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

Properties

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

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

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

Varieties

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

• totipotent cells;
• pluripotent;
• multipotent.

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

• embryonic;
• fetal;
• postnatal.

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

Growing stem cells

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

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

Application

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

In medicine

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

Treatment of various diseases with stem cells

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

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

In cosmetology

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

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

Video: Stem cell

Before we get into the actual story of growing organs, I would like to tell you what stem cells are.

What are stem cells?

Stem cells- the progenitors of all types of cells in the body without exception. They are capable of self-renewal and, most importantly, during the process of division they form specialized cells of various tissues. Stem cells renew and replace cells lost as a result of any damage in all organs and tissues. They are designed to restore the human body from the moment of its birth.

With age, the number of stem cells in the body decreases catastrophically. Newborn has 1 stem cell occurs in 10 thousand, by 20-25 years - 1 in 100 thousand, by 30 - 1 in 300 thousand. By the age of 50, only 1 stem cell per 500 thousand remains in the body. Depletion of stem cells due to aging or serious illnesses deprives the body of self-healing capabilities. Because of this, the vital functions of certain organs become less efficient.

What organs and tissues have scientists been able to grow using stem cells?

I give only the most famous examples of scientific achievements.

in 2004, Japanese scientists were the first in the world to grow structurally complete capillary blood vessels from stem cells

Japanese scientists are the first in the world to grow structurally complete capillary blood vessels from human embryonic stem cells. This was reported on March 26, 2004 by the Japanese newspaper Yomiuri.

As the publication notes, a group of researchers from medical school Kyoto University, led by Professor Kazuwa Nakao, used capillary cells generated from stem cells imported in 2002 from Australia. Until now, researchers have only been able to regenerate nerve cells and muscle tissue, which is not enough to “produce” a whole organ. Information from the site NewsRu.com

In 2005, American scientists grew full-fledged brain cells for the first time.

Scientists from the University of Florida (USA) were the first in the world to grow fully formed and engrafting brain cells. According to project leader Bjorn Scheffler, the cells were grown by “copying” the process of brain cell regeneration. Now scientists hope to grow cells for transplantation, which could help in the treatment of Alzheimer's and Parkinson's diseases. Scheffler noted that previously scientists were able to grow neurons from stem cells, but it was at the University of Florida that they were able to obtain full-fledged cells and study the process of their growth from beginning to end. Information from the Gazeta.ru website based on materials from the Independent.

In 2005, scientists managed to reproduce a neural stem cell

An Italian-British group of scientists from the Universities of Edinburgh and Milan have learned to create various types of nervous system cells in vitro using unspecialized embryonic neural stem cells.

The scientists applied already developed methods for manipulating embryonic stem cells to the more specialized neural stem cells they obtained. The results that were achieved in mouse cells were replicated in human stem cells. In an interview with the BBC, Stephen Pollard from the University of Edinburgh explained that his colleagues' development will help recreate Parkinson's disease or Alzheimer's disease "in vitro." This will allow us to better understand the mechanism of their occurrence and development, and will also provide pharmacologists with a mini-testing ground for their search. suitable means treatment. Negotiations with pharmaceutical companies are already underway.

In 2006, Swiss scientists grew human heart valves from stem cells.

In the fall of 2006, Dr. Simon Hoerstup and his colleagues at the University of Zurich grew human heart valves for the first time using stem cells taken from amniotic fluid.

This achievement could make it possible to grow heart valves specifically for an unborn child if he or she develops heart defects while still in the womb. And soon after birth, the baby can have new valves transplanted.

Following the laboratory's cultivation of bladder and blood vessels from human cells, this next step towards the creation of “own” organs for a specific patient, capable of eliminating the need for donor organs or artificial mechanisms.

In 2006, British scientists grew liver tissue from stem cells

In the fall of 2006, British scientists from Newcastle University announced that they were the first in the world to grow laboratory conditions artificial liver made from stem cells taken from umbilical cord blood. The technique used to create the 2cm mini-liver will be developed further to create a normal-sized, functioning liver.

In 2006, a complex human organ, the bladder, was grown for the first time in the United States.

American scientists were able to grow a full-fledged bladder in laboratory conditions. The material used was the cells of the patients themselves who needed transplantation.

“By biopsy, you can take a piece of tissue, and after two months its amount has multiplied several times,” explains Anthony Atala, director of the Institute of Regenerative Medicine. “We put the starting material and special substances in a special form, leave it in a special laboratory incubator, and after a few weeks we get a ready-made organ that can already be transplanted.” The first transplant was performed back in the late 90s. Seven patients underwent bladder transplantation. The results met the scientists' expectations, and now experts are developing methods for creating 20 more organs - including the heart, liver, blood vessels and pancreas.

In 2007, stem cells helped British scientists create part of a human heart.

In the spring of 2007, a group of British scientists, consisting of physicists, biologists, engineers, pharmacologists, cytologists and experienced clinicians, under the leadership of professor of cardiac surgery Magdi Yacoub, for the first time in history, managed to recreate one of the types of human heart tissue using bone marrow stem cells. This tissue acts as heart valves. If further tests are successful, the developed technique can be used to grow a full-fledged heart from stem cells for transplantation into patients.

In 2007, Japanese scientists grew the cornea of ​​the eye from stem cells.

In the spring of 2007, at a symposium on reproductive medicine In the city of Yokohama, the results of a unique experiment by specialists from the University of Tokyo were published. The researchers used a stem cell taken from the edge of the cornea. Such cells are capable of developing into various tissues, performing restorative functions in the body. The isolated cell was placed in a nutrient medium. After a week, it developed into a group of cells, and in the fourth week it transformed into a cornea with a diameter of 2 cm. In the same way, a thin protective layer (conjunctiva) was obtained that covers the outside of the cornea.

Scientists emphasize that for the first time, complete tissue human body grown from a single cell. Transplantation of organs obtained using the new method eliminates the risk of transmitting infections. Japanese scientists intend to begin clinical trials immediately after making sure the new technology is safe.

In 2007, Japanese scientists grew a tooth from stem cells

Japanese scientists managed to grow a tooth from a single cell. It was grown in laboratory conditions and transplanted into mice. The injection of cellular material was made into the collagen scaffold. After cultivation, it turned out that the tooth took on a mature form, which consisted of complete parts such as dentin, pulp, blood vessels, periodontal tissue, and enamel. According to the researchers, the tooth was identical to the natural one. After the tooth was transplanted into a laboratory mouse, it took root and functioned completely normally. This method will make it possible to grow entire organs from one or two cells, the researchers say.

In 2008, American scientists were able to grow a new heart on a frame from an old one.

Doris Taylor and her colleagues at the University of Minnesota created a living rat heart using an unusual technique. The scientists took an adult rat heart and placed it in a special solution that removed all cardiac muscle tissue cells from the heart, leaving other tissue intact. This purified scaffold was seeded with heart muscle cells taken from a newborn rat and placed in an environment that simulated conditions in the body.

After just four days, the cells had multiplied enough for new tissue to begin contracting, and after eight days the reconstructed heart could pump blood, albeit at only 2 percent capacity (based on a healthy adult heart). Thus, scientists obtained a working organ from the cells of the second animal. In the future, hearts taken for transplantation could be treated in this way to prevent organ rejection. “You can make any organ this way: kidney, liver, lung, pancreas,” says Taylor. The donor frame, which determines the shape and structure of the organ, will be filled with specialized cells native to the patient, made from stem cells.

It is interesting that in the case of the heart, you can try to take a pig’s heart, which is anatomically close to a human’s, as a basis. By removing only muscle tissue, other tissues of such an organ can be supplemented with cultured ones. human cells heart muscle, having received a hybrid organ, which, in theory, should take root well. And the new cells will immediately be well supplied with oxygen - thanks to the old vessels and capillaries left over from the donor’s heart.

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