Scientists at Tel Aviv University have printed the world’s first 3-D heart complete with blood vessels using personalized “ink” made of collagen, a protein that supports the cell structures, and other biological molecules.
The extraordinary breakthrough was reported Monday by lead scientists Prof. Tal Dvir, Dr. Assaf Shapira of TAU’s Faculty of Life Sciences and Nadav Noor, his doctoral student, in Advanced Science.
True, the heart is the size of a rabbit’s, and it doesn’t actually work yet. Dvir pointed out however that “printing” a human-size heart involves basically the same technology.
“We need to develop the printed heart further,” he said. “The cells need to form a pumping ability; they can currently contract, but we need them to work together. Our hope is that we will succeed and prove our method’s efficacy and usefulness.”
In other words, the next stage is to cultivate the rodent-sized heart in the lab, grow and mature it, and teach the artificial – but biological – organ to “behave” like a heart. The stage after that will be to transplant 3-D-printed hearts into animals, to test their functionality.
It will probably take years before this technology can create organs for effective transplant, if it ever does. Yet the Tel Aviv scientists’ achievement so far is a huge milestone in transplant science: Tissues have been printed before using three-dimensional printing technology, but they lacked the vascularization – blood vessels – essential to usability.
Printing tissues has been done before, but only simple tissues without blood vessels, the university says. “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.
Until now, scientists have managed to print cartilage and aortal valve tissues, for instance, but the challenge has been to create tissues complete with vascularization: blood vessels, including capillaries, without which the organs cannot survive, let alone function.
The Tel Aviv scientists began with fatty tissue extracted from people and separated the cellular and non-cellular components. They then reprogrammed the cells to revert into undifferentiated stem cells, which could then be nudged into becoming cardiac cells or endothelial cells.
The non-cellular materials, including proteins galore, were processed into a “personalized hydrogel” that served as the printing “ink,” Dvir explained.
Though the technology is still in its infancy, printed organs are already being used for training purposes in medical schools, and for doctors to plan out complicated surgeries.
Dvir hopes the technology can become mainstream in a decade or so, printing organs and tissues for people using their own tissues as a base.
Organ printing involves three basic stages. The first, the pre-print stage, involves scanning the organ, for instance by MRI. Stage two is printing the organ, layer by layer, and the third stage involves “maturing” the printed organ in an appropriate environment.
The heart has been considered particularly challenging to manufacture because of its sheer complexity and the pressures it must withstand.
Key to the whole point is that using the patient’s own molecules significantly reduces the probability of organ rejection, Dvir explained. His greatest hope is that organ printing will render organ donation obsolete.