Tissues from cells
Tissue engineering of the heart
Biophysicist Konstantin Agladze – about artificial ligaments,
cardiac cells and polymer nanofibersPost -science
The term "tissue engineering" is sometimes used as a synonym for the term "regenerative medicine".
In general, the term "tissue", tissue-engineering, has emerged in the last 15 years, and it reflects the fact that scientists not only began to isolate individual cells, tissues, learned how to cut them off, transplant them, but also learned how to create a selected structure from them.
1. Cell transplantationThis means that cells are taken from a living organism, that is, a piece of tissue or some organ is disassembled into individual cells (it is disassembled using enzymes that destroy the connections between these cells, but the cells are not damaged, that is, they must remain alive), then these living cells are cultured, then there are planted on a certain substrate.
An interesting fact: in order for cells to grow and develop, they must attach to some kind of solid substrate - just in a suspended state, in an incubating liquid, they do not live long. And these cells are cultivated for some time, and then they can be transplanted, for example, to a certain matrix (or what is called scaffolds in English, scaffold), tissue is built up on these scaffolds, and then, in fact, the specialized tissue that was needed is grown. In principle, it can be used as an implant, for example, for human transplantation. In this case, cells can be taken from a person and transplanted to him; in principle, there may be a situation where cells can be transplanted from one person or from one species to an individual of the same species. And there may be situations when the cells will be taken from a completely different species.
2. Artificial fabricsWhy can it be important and interesting at all?
There are many tissues that can be easily grown, that is, where cells multiply, where they can be grown. For example, these are artificial ligaments. You can make artificial ligaments on polymer fibers, that is, take live cells and plant them to a person who had a ligament defect. This is an engineering, bioengineering task, but it is no longer fundamental from the point of view of biology. On the other hand, in recent years, the areas that work with tissue engineering of the most important and very specialized organs, such as the heart, have been particularly interesting.
3. Growing tissue structureIn our laboratory, we took the heart cells of newborn baby rats, which still have the ability to aggregate and connect to each other in an excitable network after landing on a certain substrate.
These rat heart cells were disassembled, then planted on a substrate and the corresponding layer, a strip of heart tissue, was grown. Next, we used polymer nanofibers in order to give these cells the proper shape. It turns out that cells, if we plant them on polymer nanofibers of a certain type, recognize these fibers and are guided in their growth by the directions of these fibers and their location. Thus, with the help of these nanofiber matrices, it is possible to set the structure of the tissue that we want to grow. But these are nothing more than approaches to much more interesting things that are becoming possible only now, in connection with the discovery of cell reprogramming by Japanese scientist Shinya Yamanaka.
4. Artificial heart tissueIt seems unrealistic to talk about transplanting, say, rat cells to a person or taking human cells from one part of the heart somewhere and transplanting them into another.
But the discovery of Shinya Yamanaka allows you to do the following thing: cells can be taken from a person, for example from his piece of skin, and transferred to the so—called pluripotent state (that is, these highly specialized cells regain the ability to differentiate later into cells of any type in the body; "pluripotent" means that they are a lot of things they can). In this situation, tissue engineering receives a completely new and interesting impulse. Because you can take human skin cells, transfer them to this induced pluripotent state (in which, by the way, they can divide and multiply well), bring them to the proper amount, then differentiate them into, say, heart cells or liver cells, kidney cells or nerve cells – it depends from the ultimate goal. And if you make, for example, heart cells, then you can create implants from these heart cells, which will actually be the heart tissue of the person from whom these cells were taken. In fact, you can even grow a separate artificial heart, but this is a very difficult technical task, because the heart has a complex structure. But to grow a strip of heart is already quite real. Solving the problem of growing an artificial heart is, of course, a very important task that is likely to be solved in the next decade.
5. Prospects of artificial fabrics But even the formation of this strip has a huge role, because on this strip of cardiac tissue, which is identical in its characteristics to the patient's cardiac tissue, it is possible to test the effect of cardiac medications.
And it will be immediately visible how these drugs will work on this person. That is, on such a strip, you can work out the most effective selection of an antiarrhythmic for this person. Similarly, if you create a similar piece of tissue from liver cells, then you can choose drugs-hepatoprotectors or restorative drugs that will work most effectively for a particular patient. Therefore, in the near future, such patient-oriented pharmacology will probably develop very actively. And I think that in the not very distant future this will be a very important direction in modern pharmacology. And here, as always, tissue engineering is combined with polymer chemistry, and with the newest methods of molecular biology, and with modern pharmaceuticals, that is, in this case, the synthesis of sciences will be most effective.
Portal "Eternal youth" http://vechnayamolodost.ru03.06.2014