But the key achievement in this research is that it sets a precedent for future work exploring highly detailed and patient-specific, 3D printed tissues.
A human-sized heart might take a whole day to print and would require billions of cells, compared to the millions used to print these mini-hearts, Dvir said.
To create the bioinks used to build the heart, scientists took fatty cells from a patient and reprogrammed them to become pluripotent stem cells before differentiating them into cardiac and endothelial cells, which form the vascular interior. In both of these cases, it is safe to consider the hearts more as simulations rather than the real thing - made to screen drugs and study cell behaviors in a environment that is close to the real thing. While the heart isn't full-sized - it's about as big as a rabbit's heart - it still marks a breakthrough, the team says. Neither of these developments however are biological in their approach.
Israeli scientists in Tel Aviv have created a human heart that completely matches all the anatomical properties of a human patient, using a 3D printer.
"This is the first time anyone anywhere has successfully engineered and printed an entire heart complete with cells, blood vessels, ventricles and chambers", Dvir said.
He added that the heart is made from human cells, and "patient-specific biological materials". The non-cellular materials were turned into a gel that served as the bio-ink for printing, Dvir explained.
A 3-D print of heart with human tissue.
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"People have managed to 3D-print the structure of a heart in the past, but not with cells or with blood vessels", Dvir said in a statement. In the diagram below, (i) shows the CMs illuminated in pink and the CMs in orange.
Though promising, the team is quick to remind us that their hearts are not yet ready for human transplantation.
As a final stage of the study, the heart serves as a proof of concept for heart patches which have also been developed by the team. In Conclusions, the TAU researchers maintain that there is still much work to be done.
As such, CHF patients are frequently in-and-out of the hospital, require life-saving procedures to prevent risky heart rhythm, and suffer from a poor quality of life.
Until now, the university said, scientists have been successful in printing only simple tissue without blood vessels. Given the number of patients suffering from CHF each year, and its high healthcare costs, the study's researchers were determined to "develop new approaches to regenerate the infarcted heart".
After "training" the hearts to efficiently pump, the team hopes to transplant them into animals for further testing.