Translated material
Matrix for transplantologist
Artificial liver first grown in laboratory from stem cells
In the foreseeable future, a breakthrough in transplantation may occur. Scientists for the first time managed to grow a liver in the laboratory and thereby gave hope to millions of patients.While it is too early to talk about the timing of creating a liver suitable for transplantation, repairing the damaged organ using artificially grown tissue fragments is a matter of the near future.
Liver transplantation is now a technology that has already been mastered in many countries. One of the disadvantages is the shortage of donor organs. That is why tissue engineering and regenerative medicine have recently received such development. However, so far all attempts to create artificial internal organs from scratch have failed. It should be borne in mind that the liver is one of the most difficult organs to grow, because each cell in it is a separate metabolic factory that requires direct contact with the circulatory system every second. Liver growing experiments are also important because liver disease kills more people on the planet than diabetes and road traffic accidents combined.
Scientists from the Center for Engineering in Medicine at Massachusetts General Hospital, reports the journal Nature Medicine, have developed a technology consisting of only two main stages. At the first stage, a scaffold-matrix is created from the damaged donor liver, and at the second, it is “seeded” with healthy liver cells obtained from stem cells, which, in turn, are taken from the patient’s skin. Since such a liver actually consists of the patient’s own cells, there is no danger of rejection, which often happens with donor organs.
The new technique is based on experiments in 2008, during which scientists from the University of Minnesota quite successfully tried to replace diseased hearts in rats with healthy ones grown in the laboratory. However, the technique of Massachusetts doctors is a significant step forward. Since the tissue that makes up the liver is an order of magnitude more delicate and complex than the heart, which largely consists of muscles, a more gentle way of creating a structural matrix has been developed. After immersing the liver in a strong detergent (cleaner), it turns into a scaffolding matrix with intact blood vessels, consisting mainly of collagen-like connective tissue.
After the complete removal of native cells, the process of populating the matrix with new “residents” begins. Scientists introduced up to 200 million healthy cells into the scaffold-matrix four times at an interval of ten minutes, which were distributed throughout the scaffold.
At the same time, the newly formed cells were connected to the circulatory system without any problems. Thanks to intact vessels, the matrix retains a very complex system of biochemical and other signals, which is extremely difficult to replicate in a synthetic liver.
Another know-how of the technique developed in Massachusetts is that hepatocytes, very important cells of the liver parenchyma of humans and animals, are introduced into the matrix matrix. They make up 60-80% of the mass of the entire liver and perform many very important functions: they participate in the synthesis and storage of proteins, the transformation of carbohydrates, the synthesis of cholesterol, bile salts and phospholipids, detoxification, and also cause the process of bile formation.
The constructed liver lived in laboratory conditions for up to ten days. Experiments show that it is capable of destroying toxins no less effectively than natural liver. For the first time in the history of medicine, a laboratory-grown liver was successfully transplanted into rats, which worked quite satisfactorily for several hours.
It is difficult to overestimate the importance of research by scientists at the Center for Engineering in Medicine at Massachusetts General Hospital. Until now, many donor livers, for one reason or another not suitable for transplantation into patients, are destroyed. In America alone, more than a quarter of a million “defective” donor livers are lost every year, which over time could save tens of thousands of lives.
Research is at an early stage. On the way to implementing the new technology, scientists will have to solve many problems before they can begin testing the technique on humans - for example, creating a layer of endothelial cells lining blood vessels.