Chimeric patch for the heart
Biologists from Germany and Russia have created the first "Frankenstein's heart"
Biologists from MIPT and the University of Bonn have found out that fragments of cardiac tissue of different origins can be connected to each other and made to beat in unison, which makes it possible to create universal "patches" for the heart, according to an article published in the journal Biomaterials Science (Agladze et al., Synchronization of excitable cardiac cultures of different origin).
"Now everyone is just coming up to growing patches on the heart. Therefore, the question is: is it necessary to rest and create tissue engineering structures that can be inserted into the heart if they do not combine with it into a single excitable tissue? We have shown that it can form. Even if we have different cells, at different stages of development, or even from different animals. Although, of course, the animals were of neighboring species – a rat and a mouse, but it's like a monkey and a man," says Konstantin Agladze, professor at MIPT, whose words are quoted by the press service of the university.
The human and animal heart is a unique organ whose cells can simultaneously spontaneously generate electrical impulses and contract, without requiring a constant flow of "commands" from the spinal cord or brain. Current pulses are produced by so-called "driver cells", and cardiomyocytes, muscle cells, use them to reproduce contractions and relaxation at the right time.
Most heart cells are connected to each other by special protein "wires", the so-called slit contacts, which help them synchronize their work and properly pump blood through the atria and ventricles. Disturbances in the work of "driver cells", their death or damage to these contacts, as a rule, lead to the development of heart failure and other serious health problems.
For this reason, as Agladze says, the heart is only transplanted entirely today – scientists cannot yet, for example, replace dead areas of the heart muscle that died as a result of myocardial infarction using stem cell cultures or artificially grown fragments of heart tissue.
Russian scientists and their German colleagues have found out that such operations can in principle be carried out by creating a kind of analogue of the heart of Victor Frankenstein's brainchild from Mary Shelley's novel, using pieces of heart tissue of two different types of rodents.
According to the researchers, these pieces of the heart were grown in a special medium and container that facilitated the fusion of cultures of dissimilar cells. It was similar in shape to a kind of dumbbell, in the halves of which cells of rats and mice were grown, and through its "handle" they could contact each other at the electrical level.
Figure from an article in Biomaterials Science – VM.
Seeding these halves with cells of newborn and adult rats, the scientists observed their growth and interaction with each other by adding a special dye to the container, which glowed when the cells received or produced an electrical signal and transmitted it to neighboring muscle fibers.
As these experiments have shown, individual cell cultures turned out to be quite capable of communicating with each other even when they belonged to different animals or even representatives of different rodent species in the past. In the latter case, according to the researchers, the electrical signal did not propagate as fast as between pieces of heart tissue of one animal species, but it was still transmitted further.
All this indicates that "patches" of cardiac tissue can really be used to combat the effects of ischemia, heart attacks and other interruptions in the work of the heart. On the other hand, as Agladze and his colleagues emphasize, such experiments cannot yet be carried out on humans, since scientists have recorded an unusual attenuation of the signal at some frequencies during the transition from the "patch" to the rest of the heart muscle and back, which may increase the risk of arrhythmia and threaten the patient's life.
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27.06.2017