World’s first 3-D printed heart

The discovery is a major breakthrough in the medical field. Until now the scientist had successfully printed only simple tissues without blood vessels. But this is the first time the scientists have successfully engineered and printed a whole heart replete with cells, chambers, ventricles and blood cells. Research in this study was jointly conducted by prof. Dvir, Dr Assaf Shapira of TAU’S Faculty of life sciences and Nadav Moor, a doctoral student in prof. Dvir’s lab. As far now the 3-D printed heart is the size of rabbit heart and doesn’t beat. Currently, it cannot be deployed in humans for practical use because of its tiny size.

Why 3-D Printed heart? According to WHO Heart diseases is the number one and major cause of death among people. It is estimated over 18 million people die worldwide due to various heart diseases. And the only treatment available for patients when they reach the final stage heart failure is- Heart transplantation. Heart transplantation through donation is a rare scenario. Hence there is an urgent need to develop new approaches to provide relief for the diseased heart. Scientists always find a way to solve such critical problems hence they came up with Engineering and Printing 3-D hearts in the lab. And if it turns out to be successful then hospitals can have 3-D organ printing machine very soon.

Bioprinting with the Bio-ink

When biology, chemistry and technology meet at a junction, 3-D bioprinting emerges. 3-D bioprinting is used in tissue engineering but it lacks printable material- The bio-ink. Bioprinting makes use of concept similar to a computer-generated 3-D design, with adjustable parameters and bio-additive manufacturing technologies to ‘print’ exact geometries that mimics automatically correct biological structures. The purpose of this bioprinting of tissues is to replace and/or repair damaged tissues, bio-inks used here must meet certain criteria which are considered critical for clinical application. Mostly the bio-inks should be biocompatible and biodegradable with non-toxicity parameters. These parameters play a vital part in determining the transfer and movement of nutrient, oxygen and waste through the engineered tissues. Bio-inks are responsible for the construction of engineered bio-physical-functional tissues and organs. Currently, the bio-inks are made up of

1. Natural polymer

1. Synthetic polymers

Most of the Natural polymer possess cellular interactivity and biocompatibility, but it is deprived of strong mechanical properties which are required to maintain structural stability and integrity during physical stress within the in vivo microenvironment. On the other hand, synthetic polymers are in contrast to natural polymers. But they have an advantage in modification. This property of modification can be used to induce bioactivity along with their control over structure and architecture. The ‘ideal’ bio-ink, should, exhibits a range of properties such as good printability, structural fidelity and mechanical strength, as well as biocompatibility and bioactivity. The experiment for the very first time in printing 3-D heart was carried out with fully personalised, non-supplimented materials as bio links. The bio-ink is made up of collagenous nanofibres which behave as a weak gel at room temperature and upon heating, to 37°C became stronger. Here two cellular bio-inks were created. The cardiac cell bio-ink, used for printing the parenchymal tissue and other  bio-ink consisted of blood vessel-forming cells. How is it done? Initially, the first step performed by scientists was to take a biopsy of fatty tissue from the patients. Later cellular from non-cellular material was separated. The fatty tissue cells were reprogrammed to pluripotent stem cells, which has the potential to develop into a variety of cells types required to develop a heart. The extracellular matrix which contained structural proteins like glycoproteins and collagen was processed into a personalized hydrogel -“The bio-ink” The stem cells were mixed with the bio-ink and from the mixtures, the cells efficiently got differentiated to cardiac cells and immunocompatible engineered patches. This was aimed to be specific to patients. In order to ensure minimum immune response complete autologous materials was  prioritized. In this strategy, the bio-ink was used to print thick, vascularized, and perfusable cardiac patches. However, these cardiac patches lacked blood vessel network that matched the anatomical architecture of the patient’s vasculature. This tiny pre-engineered vasculature within the parenchymal tissue was proved to be critical for patch survival and function after transplantation. Since the bio-inks originated from the same patient, the engineered patches will not invoke an immune response after transplantation hence needs of immunosuppression treatment is ward off.

The detail description of the complete experiment is published in the journal Advanced science.

RESEARCHER’S STATEMENTS

“This is the first time anyone anywhere has successfully engineered and printed an entire heart replete with cells, blood vessels, ventricles, and chambers”.

“Maybe, in 10 year, there will be an organ printer in the finest hospitals around the world, and these procedures will be conducted routinely.”

-Lead researcher prof. Tal Dvir Point of view 3-D bioprinting promises to be a futuristic approach when organ implantation is on huge demand. 3-D bioprinting also proves to be a novel invention where there is no longer need of living or deceased human donation or animal transplantation. Although its promising approach, several challenges still remains. This includes engineering of the actual size of the functioning organ with high cell number. The printed heart in this research is still limited, strategies to image the entire functioning heart are required. And advanced technologies to accurately print these small-diameter blood vessel within the thick structure should be developed.  If at all 3-D bioprinting of organ becomes a reality then testing of pharmaceutical drugs for efficacy and potency could be performed on this engineered 3-D organs relieving animals.  But with the advancement in technology comes the ethical issues. Obviously, 3-D printing organ is expensive which literally means only a few members of society will be benefited out of it. This means it will not prove a game-changer to all sections of society.  Boundaries need to be set up on the kinds of the object to be created. Questions arise on how to categorise the 3-D organs and to whom it belongs? Also, should it be allowed to grow these organs privately if not then who should take the responsibility to grow them? Along with this it also raises the question whether these technologies should be used to enhance the potential of humans beyond normal. Hence it is the responsibility of scientific and engineering communities to frame up the guidelines and further work upon it. These questions need to be considered by health policy- maker, clinicians and societies. Before the technology is fully developed, it is better to ensure that the new medical revolution meets patients expectation for safe and effective treatments. Also, it should ensure that the technology meets social demands for secure, fair and cost-effective healthcare.