Scientists have been trying to understand how amphibians - for example, newts and salamanders regenerate cut off tails, legs, jaw. Moreover, they regenerate damaged heart, and eye tissue and spinal cord. The method used for amphibians of self-repair, became clear when the researchers compared the regeneration of Mature individuals and embryos. It turns out that in the early stages of the cells of the future being immature, their fate is likely to change.

It showed the experiments on embryos frogs. When the embryo is just a few hundred cells, it is possible to cut out a piece of tissue, which is destined to become to become skin, and put it in the area of the brain. And this fabric will become part of the brain. If this operation is performed with a more Mature embryo, from skin cells still developing leather - right in the middle of the brain. Because the fate of these cells is already predetermined.

For most organisms, cell specialization that one cell is the cell of the immune system, and the other, say, part of skins is a one-way street, and the cells adhere to our "specialization" to the death.

And the cells of amphibians are able to turn back time and return to the moment when the mission could change. And if Triton or Salamander lost paw on the damaged part of the body cells of the bone, skin and blood cells become without distinguishing features. All this mass again "newborn" cells (called blastemas) rapidly begins to divide. And in accordance with the needs of the "current time" to become cells of bones, skin, blood,... To become in the end a new paw. Better still.

Until liver come

And as a person? There are only two types of cells that can regenerate, is blood cells and liver cells. But here the principle of regeneration different. When the mammalian embryo develops, little cells remain aloof from the process of specialization. This is stem cells. They have the ability to replenish blood or dying liver cells. Bone marrow also contains stem cells that can become muscle tissue, fat, bones or cartilage - depending on what nutrients they are given. At least half pans.

If you enter the bone marrow cells in the blood of mice with damaged muscles, these cells are collected in the damage and improve it. However, what is true for the mouse, does not apply to a person. Alas, the muscle tissue of the adult person is not restored.

Some mouse - know how

Is there a chance that the human body is able to regenerate the missing parts? Or similar remains the stuff of science fiction?

Recently, scientists knew that mammals can't regenerate. Everything has changed suddenly, and, as often happens in science, quite by accident. Immunologist Ellen Heber-Katz from Philadelphia once gave his assistant ordinary assignment: to pierce ears laboratory mice to fasten them tags. In a couple of weeks Heber-Katz came to mice with ready tabs, but... not found in the ears of holes. Naturally, the doctor gave a beating to his assistant and, despite his vows, she got down to business. A few weeks passed and the dazed eyes of scientists appeared in the purest mouse ears without any hint of sajileniu wound.

This strange case made of Gerber-Katz make absolutely incredible assumption: what if the mouse just regenerates the tissue and cartilage to fill unnecessary holes? On close examination, it was found that in damaged areas of the ears is blastema same unspecialized cells, as in amphibians. But mouse-mammals, they should not have such abilities...

But as other parts of the body? Dr. Heber-Katz cut mice piece of tail and... got 75% regeneration!

Perhaps you are waiting for that now I'll tell a doctor cut mouse paw... in Vain. The reason is obvious. Without burning the mouse just die from loss of blood - long before, when will (if ever starts) regenerate lost limbs. And moxibustion excludes the appearance of blastema. So the full list of regenerative abilities Katavsky mice could not figure out. However, and this is already a lot.

But, for God's sake, do not cut the tails of their home mice! Because in Philadelphia living laboratories special pet - with damaged immune system. The conclusion from his experiments Heber-Katz did this: regeneration inherent only in animals destroyed T-cells (cells of the immune system).

And in amphibians, by the way, no immune system. So in the immune system and rooted the solution of this phenomenon. Mammals have the same need for regeneration of tissues, genes, as amphibians, but T-cells do not allow these genes work.

Dr. Heber-Katz believes that the organisms originally had two ways of healing of wounds is the immune system and regeneration. But during the evolution of both systems have become incompatible with each other - and had to choose. Although regeneration may at first sight seem to be the best choice, T-cells to us - necessitous. After all, they are the primary weapon of the body against cancer. What's the use to be able to grow again lost the hand, if simultaneously in the body booming cancer cells?

It turns out that the immune system, protecting us from infection and cancer, simultaneously inhibits our ability to "savremenu".

What kind of cell press.

Doros of Plastic, the head of the Boston company Ontogeny, I am sure that one day we will be able to start the process of regeneration, even if you do not understand all the details to the end. Our cells are kept innate ability to grow new body parts, just as they did during fetal development. Instructions on growing of new organs recorded in the DNA of each of our cells, we just need to get them enable" your ability, and then the process itself will take care of itself.

Specialists Ontogeny are working to create tools that includes regeneration. The first is already prepared and may soon be approved for sale in Europe, USA and Australia. It is a growth factor called OP1, it stimulates the growth of new bone tissue. OP1 will help in the treatment of complex fractures, when two pieces of broken bones strongly do not coincide with each other and therefore cannot grow together. Often in such cases limb amputated. But OP1 stimulates the bone so that it grows and fills the gap between the pieces of the broken bone.

All you have to do doctors is to give a signal to the bone cells "grew", and the body itself knows how many bones and where. If such growth signals to find all types of cells, to grow new leg can be via multiple injections.

When the leg will become an adult?

However, on the way to such a bright future there are a couple of traps. First, the stimulation of cells to regenerate can lead to cancer. Amphibians that have no immune protection, otherwise protected from cancer - instead of tumors they grow new body parts. But mammalian cells so easy uncontrolled collapse division...

Another trap is the problem of time. When in embryos begin to grow limbs, chemicals, dictating the form of a new limbs, easily spread by tiny body. In adults, the distance is much greater. You can solve the problem by forming a very small limb, and then begin to grow. Do newts. For growing new limbs they have just a couple of months, but we are a little more. How long will it take to grow a new leg to normal size? London scientist Jeremy Broks thinks that not less than 18 years...

But the Plastic is more optimistic: "I see no reason why you cannot grow a new leg for a few weeks or months"So when the doctors will be able to offer people with disabilities new service - grow of new legs and arms? Of plastic says that in five years.

Implausible? But if five years ago someone said that they will clone a human, would he not have believed... But then was Dolly the sheep. And today we, forgetting about the awesomeness of this operation, discussed quite another issue is whether the government's right to stop scientific research? And to force scientists to look for a unique experiment piece of extraterritorial ocean? Although there are quite unexpected role. For example dentistry. It would be good if the lost teeth had grown... and we reached the Japanese scientists.

System of their treatment, according to ITAR-TASS, based on the genes that are responsible for the growth of fibroblast - those tissues that grow around the teeth and keep them. According to scientists, at first they checked his method on the dog, which had previously developed a severe form of parodontosis. When all teeth fell out, the affected areas handled by the substance, which consists of these same genes and agar-agar - acid mixture, providing a nutrient medium for reproduction of cells. After six weeks the dog erupted teeth. The same effect was observed in monkeys with surfaced before the Foundation of the teeth. According to scientists, their method is much cheaper prosthetics and for the first time allows you to return in the literal sense of their teeth vast number of people. Especially if to consider, that after 40 years the tendency to periodontal disease occurs in 80% of the population of the planet.