The University of Southampton

Author: Connor McFarlane

Pioneering the Pulse: The Future of Artificial Hearts

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In the intricate landscape of medical science, perhaps no feat is as remarkable as the creation of artificial hearts. These remarkable devices stand as a testament to human ingenuity and the relentless pursuit of innovation in healthcare. As we stand at the cusp of a new era in medicine, it’s important to explore the history, current challenges, and the promising future of artificial hearts.

A Journey Through Time: The History of Artificial Hearts

The genesis of artificial hearts can be traced back to the 1950s when Dr. Paul M. Zoll developed the first external pacemaker. This monumental achievement laid the foundation for further advancements in cardiac care. However, it wasn’t until 1982 that Dr. Robert Jarvik’s creation, the Jarvik-7, became the first artificial heart implanted in a human. Though it was initially intended as a temporary measure, it marked a significant milestone in medical history.

Jarvik-7: the first artifial heart implanted in a human

The Present Landscape: Temporary Solutions Amidst Growing Challenges

Today, artificial hearts primarily serve as a bridge for patients awaiting heart transplants. However, the demand for heart transplants far exceeds the available supply. One of the most significant challenges facing artificial hearts is the interaction between platelets and artificial surfaces, which triggers the activation of contact proteins and leads to coagulation. Consequently, patients require therapeutic intervention, often in the form of medications, to mitigate these effects. However, despite these efforts, there are inherent limitations on the duration for which artificial hearts can be utilized due to this phenomenon.

In the UK, the British Heart Foundation reports that over 900,000 people live with heart failure, with an estimated 1,000 new cases diagnosed each month. Each year, around 200 people in the UK are added to the heart transplant waiting list. Regrettably, due to the scarcity of donor organs, many patients face the grim reality of heart disease, facing long stays in hospital with some tragically passing away while awaiting a life-saving transplant.

Evie: admitted to hospital over a year ago and still awaiting a heart transplant

Looking Forward: The Promise of Future Artificial Hearts

As we venture into the future of artificial hearts, a myriad of technological advancements offer hope for overcoming current limitations and revolutionizing cardiac care. One area of significant progress lies in battery technology. Traditional power sources for artificial hearts, such as external batteries or power cords, present challenges in terms of mobility and infection risk. However, the development of smaller, more efficient batteries promises greater freedom and convenience for patients, allowing them to lead more active lives without constant tethering to external power sources.

Biomaterials also play a pivotal role in the advancement of artificial hearts. Researchers are exploring innovative materials that closely mimic the properties of natural heart tissue, reducing the risk of immune rejection and clot formation. These biocompatible materials not only enhance the longevity of artificial hearts but also promote better integration with the surrounding tissues, minimizing the need for anticoagulant therapy and reducing the risk of complications.

Incorporating advanced sensors into artificial hearts enables real-time monitoring of vital parameters such as blood flow, pressure, and heart rate. This continuous stream of data allows for early detection of potential issues, enabling timely intervention and improving patient outcomes.

Ethics of growing Synthetic Human embryos

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The Ethics and laws around growing Human embryo’s and their status have been a contentious topic since the first experiments deriving stem cells in 1981. And it is an area in which the law leaves areas unclear given recent advancements in synthetic embryos. Currently in the UK embryos are not allowed to be grown outside of the womb for more than 14 days, the reasoning behind this being that it is the best guess for the last point in which an individual, instead of multiple people, could develop from a single embryo. Given these rules, and the understanding that Embryos cannot grow into foetuses outside of the womb, in many countries embryos are not legally considered people. This idea has been challenged recently in the US, where the Alabama supreme court ruled that frozen embryos used in IVF are considered children.

What are synthetic embryos

Embryos are the initial stage of development of multicellular life, starting as the blastocyst (formed from the fertilisation of the egg cell by a sperm cell) implants onto the walls of the uterus. For most of history this was the only way to form an embryo, until 2022 when a team at the Weizmann Institute in Israel manipulated mouse stem cells, which then grew into embryo like structures. This work has been continued and since then scientists at the University of Cambridge have created synthetic mouse embryos that have formed with a brain, nervous system and beating heart.

Natural (top) and synthetic (bottom) embryos side by side to show comparable brain and heart formation. Image credit: Amadei and Handford

Ethics of using synthetic embryos

Research using synthetic embryos has many touted benefits, many pregnancies fail in the first weeks when the cells that will become the embryo, placenta and yolk sac differentiate, and the hope is synthetic embryos will allow further research into this area, where current research with human embryos is limited due to the 14 day rule. It also allows research in understanding the development of the brain, as this starts developing later than 14 days and cannot be examined closely inside the womb. The rational behind these synthetic embryos being developed for longer periods of time is that they are models of the human embryo, and would not be able to develop into the foetal stage.

There are many questions on the morality of creating synthetic embryos. If the synthetic embryo is recognised as children, much alike the case in the Alabama Supreme court, then the embryo could be seen as a clone of the person who donated the stem cells, Importantly Human cloning is banned in most countries around the world and thus would make the development of these embryos illegal.

Currently the only limit to this research in the UK is that it is illegal to implant synthetic embryos into a human womb.  This leaves a wide range of possibilities for research, and questions are being asked about what stage these embryos can be grown to before they are seen as alive. This question has yet to be agreed on regarding the development of natural foetus’ and so likely will be a long time before it is answered.

Links

Epstien, K. (2024) Alabama IVF ruling: What does it mean for fertility patients?, BBC News. Available at: https://www.bbc.co.uk/news/world-us-canada-68366337 (Accessed: 06 March 2024).

Collins, S. (2022) ‘Synthetic’ embryo with brain and beating heart grown from stem cells by Cambridge scientists, University of Cambridge. Available at: https://www.cam.ac.uk/stories/model-embryo-from-stem-cells (Accessed: 06 March 2024).

Villalba, A., Rueda, J. and de Miguel Beriain, Í. (2023) ‘Synthetic embryos: A new venue in ethical research’, Reproduction, 165(4). doi:10.1530/rep-22-0416.