The generation of artificial organs could be, in the near future, a good solution to the problems caused by traditional organ transplantation, which, in addition to depending on the availability of compatible donors, can cause rejections in the recipient.
Bioprinting is a promising technology, as it consists of generating organs and tissues tailored for each patient using their own cells and relying on 3D technology . To achieve this, many obstacles have to be overcome, because as we already know, living organs are very complex structures that work connected as a whole.
Now, a team of scientists from the Human Genome and Stem Cell Research Center (HUG-CELL) of the University of São Paulo (Brazil) has succeeded in printing a kind of mini-livers capable of carrying out the functions of this organ such as produce protein, store vitamins, and secrete bile. The technique developed, as described in an article published in the journal Biofabrication , makes it possible to produce liver tissue in the laboratory in just 90 days and, in the future, could represent a real alternative to organ transplantation.
It is not the first time that tissue tissue has been produced with 3D technology, but until now the problem was to get the cells to maintain their functionality over time without losing contact between them. To get around this stumbling block, the researchers changed the approach and instead of printing individual cells, they developed a method to group them together before printing.
The work combined bioengineering techniques, such as cell reprogramming and culturing of pluripotent stem cells, with 3D bioprinting. Thanks to this strategy, the tissue produced by the bioprinter maintained liver functions for longer than other groups reported in previous studies.
A complete liver in 90 days
The three stages that are needed to complete the entire process are: differentiation, printing and maturation . The first step consists of cultivating the patient’s blood cells to convert them into induced pluripotent stem cells, a technique for which the Japanese Shinya Yamanaka received the Nobel Prize in Medicine in 2012. Thanks to this process, the adult cells return to the embryonic state. , with the potential to specialize and become part of any tissue in the body.
In the next stage, the scientists induced the differentiation of liver cells, and then they were grouped into what they called ‘spheroids’, which constitute the tissue as such and maintain its functionality for a longer time. “ We started the differentiation process with the cells already grouped together. They were grown in agitation, and the groups formed spontaneously ”, explains Ernesto Goulart, lead author of the study. Once obtained, the spheroids are mixed with a biotin – fluid similar to a hydrogel-, and printed. The resulting structures undergo a maturation process in culture for 18 days.
Although these livers are not yet full-organ, the change in approach involved in printing these spheroids or groups of already differentiated cells represents a promising advance. “In the very near future, instead of waiting for an organ transplant, it will be possible to take cells from the patient and reprogram them to produce a new liver in the laboratory, ” says Mayana Zatz, director of HUG-CELL and author of the article.
Referencia: Goulart et al 2019. 3D bioprinting of liver spheroids derived from human induced pluripotent stem cells sustain liver function and viability in vitro. Biofabrication 12 015010
