3D printed hearts

Advances in 3D-printing technology present the prospect of building a working heart from human tissue, as Lorena Tonarelli reports

Three-dimensional (3D) printing is a major driver of innovation in cardiovascular medicine, with surgeons already using the technology to create synthetic heart models that enable them to plan or even rehearse complex operations – a procedure that can substantially reduce surgery times and improve patient outcomes.

Now the technology is moving to more cutting-edge applications, including an elastic soft silicone membrane shaped to match the outer layer of the heart’s wall, containing sensors that measure pH or acidity, temperature and mechanical strain or deliver electrical impulses.

Developed at Washington University in St Louis, Missouri, the device could monitor cardiac performance, “providing clinicians with a set of internal eyes guarding patients’ progression into and from disease”, says Professor Igor Efimov, who led the project. As such, it could provide instant feedback on therapies, correct arrhythmias or irregular heartbeat and predict impending heart attacks.

Scientists are turning to 3D-printing technology to build complete hearts using human tissue

More ambitiously, scientists are turning to 3D-printing technology to build complete hearts using human tissue. “The goal is to recreate the various components of the organ and assemble them together,” explains Dr Stuart Williams, director of the Bioficial Organs Programme at the University of Louisville, Kentucky. “We are currently building a 3D-printed heart valve using the patient’s own cells, which will reduce the need for blood thinners and the risk of rejection. We have also begun work to recreate cardiac contractile cells and the heart’s electrical system.”

So far, US and European researchers have 3D printed, from living (but not necessarily human) tissue, sections of cardiac muscle, valve conduits and blood vessels, which could soon be available to patients as replacements for damaged parts. According to Kevin Shakesheff, professor of tissue engineering at the University of Nottingham: “This appears to be a realistic goal for the next ten years. And the UK is set to be among the first to offer the technology, with leading stem-cell and 3D-printing scientists, world-class heart surgeons and state-of-the-art research facilities, such as the Cell Therapy Catapult at Guy’s Hospital, London.”

However, it may take several decades before 3D-printed living hearts become available for transplant, largely because of the complexity of the structures that must be replicated and the need for them to work perfectly the moment they are implanted.

Jonathan Butcher, who researches tissue-engineered aortic heart valves at Cornell University, Ithaca, New York, says: “These are exciting times, offering great opportunities to advance cardiovascular treatment. But there are engineering and biological challenges to overcome before 3D printing moves into the clinic. We need to raise awareness of both opportunities and challenges, so that governments and industry worldwide continue to support the progress of the technology, and propel it where it needs to go.”