Israeli researchers have created a very small heart of human tissue with a 3D printer. The prototype is about the size of a cherry, which is about the size of a rabbit's heart, said study director Tal Dvir of the University of Tel Aviv. It is comparable to the heart of a human fetus.
The heart consists of tissue and blood vessels and has chambers, the researchers report in the journal "Advanced Science". However, it does not work because the cells can not yet contract synchronously. It will therefore take years until such an organ can be used on a human, the researchers emphasize.
Researchers have long been working on recreating living tissue with the 3D printer. In 2016 researchers created cartilage, bone and muscle tissue in the 3D printer. However, these were only used on mice and rats. In another experiment, mice even got offspring with artificial ovaries. Even kidneys and their complicated cellular structures can be printed, which are necessary for the filtration of blood and the production of urine.
Rip prototypes in a special bioreactor
"We biopsy adipose tissue from a patient," said biologist Dvir on the current experiment. The resulting cells are reprogrammed into stem cells. "These in turn differentiate into heart cells, cells of the blood vessels and others," Dvir explained. The cartridges of the 3D printer also contain supportive substances that support the tissue to be printed. These are also from the patient. From these "bio-inks" the 3D printer then generated the mini-heart.
"The heart is completely compatible with the patient because it is made from its own tissue and therefore will not trigger immune backlash," said Dvir. This is a decisive advantage over donor organs, which lead to defense reactions of the body. Organ recipients have to take medication for their entire life. The great advantage of the 3D procedure is that each organ could be perfectly adapted to the size and age of the patient.
According to Israeli researchers, this is the first time that a whole heart has been printed with cell tissue and blood vessels. In similar experiments hitherto only synthetic substances or other natural tissue have been used. Now the researchers want to ripen the prototype in a special bioreactor. Within one year, such hearts should be tested in animal experiments.
The biggest problem, however, is not the printing technique. It is not enough to position the cells in the right place. They also need to work together so that they can take over organ functions. It will take a while for doctors to comfortably express needed organs.