From internal procedures like knee or hip joint replacements, to external ones like replacement limbs, prosthetics allow hundreds of thousands of people each year increased quality of life and mobility. As someone with a background in animal ecology, I became interested in how prosthetics for animals might be created; they have very different morphology and requirements to humans, with stronger forces being exerted on them, and the animal’s natural behaviour needs to be considered.

One example of prosthetics being used for non-human patients is, of course, Prof. Noel Fitzpatrick, who treats pets around the UK, for example Oscar, a cat who lost his hind limbs, and had them replaced with Intraosseous Transcutaneous Amputation Prosthetics (ITAP), where holes are drilled into the residual limb’s bone and the implants are then attached, allowing the skin to bond to the prosthetic, creating ‘pegs’ onto which the limb itself can then be attached following a recovery period. Similar methods for bone-anchored limb prosthetics are being considered for humans, though still in its early stages. Even a recent study performed on 16 cats and 4 pigs finds issues with infection at the stoma, and a high failure rate of integration. Regardless, it is true that prosthetic techniques being developed in the field of veterinary science can have implications for human medicine.

But what I was most interested in was wild animals, whose requirements would be a lot different to pets’. That’s how I ran into Winter, a bottlenose dolphin whose tail was lost in a crab trap in 2005. Over a year and a half later, with a lot of work from a dedicated team, a prosthetic tail was completed and fitted onto Winter. Unlike an arm or a leg, a tail can’t simply stay solid as the animal moves, but must move along with it, hold its position under water and under the force of a large animal using it to propel its movement, not cause further injuries to Winter, and, of course, perform its function as a tail. The resulting material created from this research, WintersGel, can now be used for human patients, especially athletes as it is softer and distributes weight more evenly than other liners, reducing pain and pressure exerted by the limb.

There are many other cases of prosthetics being used in wildlife, from an injured Bald Eagle with a prosthetic beak, to a young elephant with a prosthetic foot, to a 3D-printed leg for a Secretary Bird at a bird park who injured her leg, and, prevented from engaging in her natural behaviours, began engaging in behaviour associated with poor welfare. There has even been a tiger in east Germany who, experiencing pain from arthritis, had a hip replacement, although a more recent operation hasn’t been as successful, and the tiger who underwent it had complications. This, as well as other cases where operation may have had more negative than positive consequences for the animal, raise the importance of ethical considerations in wildlife prostheses. Are these operations always necessary? Do they increase the animal’s quality of life, or do they add unnecessary stress to an animal’s life who might not survive for very much longer, or who, unable to engage in their full behavioural repertoire, might exhibit stereotypies or other negative behaviours? With humans, we can operate on the basis that each of us should have autonomy over what happens to our own bodies, and that informed consent is crucial in these and other procedures, but who should get to decide when the patient can neither understand what is happening nor communicate their preferences on the matter?

From the lectures on tissue engineering, I found the idea of fixing the body with the same materials that make up the body really interesting, and how this can help with rejection which is faced by foreign materials in the body. This led me to look more into recent advances in tissue engineering, where I came across this news article about a new biomaterial with the potential for healing damaged heart tissue after a heart attack.

What is it?

A team at the University of California San Diego has developed a new hydrogel, which is a polymer chain complex that can hold a lot of water. The hydrogel contains extracellular matrix (ECM), from the myocardium, or heart muscles. The ECM has been decellularized to isolate the matrix, enzymatically digested, and fractionated. In the body, cells exist inside a matrix, which contains proteins and other molecules to give structure to tissues and aid in cell communication. The original hydrogel that was developed was too large to target leaky blood vessels. This issue was solved by centrifuging the gel in its liquid stage to remove larger particles.

How does it work?

The hydrogel is injected intravenously, taking advantage of the bloodstream to access hard to reach organs. After a heart attack, gaps form between the endothelial cells which line blood vessels. When the hydrogel reaches the damaged tissue, it binds to these cells, bridging these gaps and promoting new cell growth and repair, and also reducing inflammation. The gel takes roughly 3 days to degrade after administration.

In their initial clinical trial, the gel was directly injected into the heart muscle. This came with the disadvantage of having to wait at least a week after the heart attack, as injecting the damaged tissue by needle directly after is likely to do more harm than good. Intravenous injection can be done immediately. The hydrogel can then work together with other treatments such as angioplasty or a stent. In addition, the gel is more evenly distributed around the tissue rather than being concentrated around the site of injection.

The Next Steps

This new way of administering the gel has been successfully tested on rodents and pigs to treat damaged heart tissue. The research group are looking to get authorisation from the FDA to perform human trials, with plans to start in the next couple of years. They are also exploring the potential of the hydrogel to treat other inflammatory diseases such as traumatic brain injury and pulmonary arterial hypertension with preclinical trials on rodents.

In the UK there are around 100,000 hospital admissions every year for heart attacks- or one every five minutes. Over the past 50 years, there has been major advances in treatment and survival. In the 19080s roughly 25% of people having a heart attack would die, nowadays, if treated quickly, the chance of dying during a heart attack is 2-4%. In the future this number will hopefully reduce even more with advances in bioengineering.

References

British Heart Foundation, 2023. UK Factsheet. [Online]
[Accessed 9 March 2023].

Spang, M. T. et al., 2022. Intravascularly infused extracellular matrix as a biomaterial for targeting and treating inflamed tissues. Nature Biomedical Engineering, 29 December, Volume 7, pp. 94-109.

Thomas, M., n.d. Focus on: Heart Attacks [Interview] n.d.

University of California – San Diego, 2023. Groundbreaking Biomaterial Heals Tissues From the Inside Out. [Online]
Available at: https://scitechdaily.com/groundbreaking-biomaterial-heals-tissues-from-the-inside-out/ [Accessed 8 March 2023].

Recently my family received the unfortunate news that my grandmother has been diagnosed with stage 1 Parkinson’s disease. This came as a shock to me and since then I have been trying to educate myself about this condition and figure out the best way to support her.

Parkinson’s disease (PD) is a progressive neurological disorder affecting more than 10 million people worldwide. This is caused by the degeneration of dopamine-producing cells in a region of the brain called the substantia nigra leading to a decrease in the dopamine neurotransmitter that is essential for controlling movement and coordination. This decrease in dopamine leads to motor symptoms including hand tremors, slow movement, limb rigidity, imbalance, and non-motor symptoms including cognitive impairment, mental health disorders, sleep disorders, and so on.

What causes this degenerative condition?…we don’t know!

The underlying mechanisms responsible for the deterioration of nerve cells associated with PD are not yet fully understood. Researchers believe a combination of genetic and environmental factors cause the dopamine-producing cells to die. Some of the factors that have been linked to PD include aging, exposure to certain toxins, head injuries, and genetic mutations (Parkin and PINK1 gene).

5 stages of Parkinson’s disease

PD can start with mild symptoms and go unnoticed, but as the condition worsens, symptoms become more obvious and can have a big impact on daily life.

Treatments, not cures: Living with Parkinson’s disease

• Medications: Drugs such as levodopa, dopamine agonists, MAO-B inhibitors, and COMT inhibitors can help manage the motor symptoms of PD.
• Physical therapy: Regular exercise can help improve motor function, muscle strength, increase flexibility, and reduce stiffness, which can be very important in the early stages of the disease.
• Deep brain stimulation: This procedure involves implanting a device called a neurostimulator which sends electrical impulses to specific parts of the brain to lessen the symptoms of PD.

My grandmother’s doctor has prescribed medication to help manage her symptoms and advised her to stay active in any way she can. Is this enough? PD usually develops in people over 60 but it can also occur in younger people, what about them? Is this the only solution?

Unsatisfied with this information, I continued researching until I came across a useful article that offered fresh new perspectives; Stem cells: Parkinson’s treatment breakthrough. Preclinical studies using mesenchymal stem cells have shown promising results for treating PD; aiming to reduce neuroinflammation, modulate the immune system to prevent disease progression, and repair or even replace, the damaged or lost, dopamine-producing cells in the brain. This could lead to significant improvements in motor symptoms like tremors, stiffness, rigidity, and difficulty with movement.

While more research is required to confirm the effectiveness of stem cell therapy on PD, this gives me hope for the future. Stem cells are so powerful, they can renew themselves indefinitely, and be manipulated in the lab to develop into specific cell types, possessing a tremendous potential to be used in therapies to treat a variety of diseases and conditions, why not PD be one of them?

Cloning is a phenomenon that scientists use to make exact copies of living cells and genes. Dolly the sheep was a breakthrough where scientists had cloned an entire sheep using the complete genome of another animal adult. As miraculous as this may seem, there is an everlasting debate regarding the ethics of this technique. Questions rise as to whether cloning will ever been seen as right or wrong.

Why was I fascinated by this topic?

During a workshop today I came across a case study about a stem cell scientist, Woo Suk Hwang, who sparked my interest towards the debate on ethics, claimed to have utilised eggs from ‘paid donors and junior members of his team’ after a long time denying this very fact. At the time of Hwang’s research, paying donors for their eggs was not illegal in Korea but he was put in a position of jeopardy due to his ‘ethical and unlawful’ actions. 

 This raises a question of ethics as to whether it was fair for Hwang to be penalised for performing such invasive procedures on paid donors, or whether due to their being no law against it should mean that Hwang should not have to be punished.                                         

I found this interesting as there is a very broad spectrum as to what one may find right and what they may find wrong, and often we are left in a grey area of neither or. It could be argued that the procedure was unethical as an incentive behind a donation makes you question whether the women was donating her egg because she wanted to or had to. For example, it could also be seen as an easy fix out of poverty which leads onto the argument whether one with a ‘supposed to have moral high ground’ should be performing a procedure on such donors.

On the flip side, Hwang did not do something that was against the law at the time and I could argue that if incentives had not been put in place, we would have less donations and more people would suffer as they would not be able to get any treatment as there would be a lack of it.

Will there ever be an end?

It made me question whether such a case would ever come to a conclusion to whether his actions were right or wrong. Would there have to be an international law put into place for the whole world to follow? And even so, the law differentiates from ethics and many different cultures have different stances and viewpoints. In Hwang’s case, a researcher had donated her organs as she had made a mistake during the experiment setting them back months, and due to this she felt obligated to ‘ make right of a mistake’ which is a collectivist and patriotic way of thinking, which was common in South Korea. Other cultures may be more lenient with their mindset when making mistakes.

Ethics will always be a topic for debate and there will always be two opposing opinions as with Hwang’s’ case I could argue both cases and personally still be torn whether he was right or wrong. In conclusion, it may just all come down to what opinion / viewpoint is the lesser of two evils?

Upon starting my Engineering Replacement Body Parts module, the prosthetics joints and limbs lectures sparked a particular interest. It became evident to me that when an individual loses a fully functioning body part, alongside the obvious physical loss, there is also an element of mental loss in their sense of being. There becomes an immense divide between being ‘disabled’ and ‘able’.

Over half of the world’s population suffers from some form of cognitive, motor or sensory disease, and at what expense? The lack of efficient technology?

So… What if there was a way to enhance people’s capabilities beyond their losses, restore motor function and finally bridge that gap between limitation and potential? Luckily enough, we live in a period of time where there CAN be a way. A way we now call bionics.

Bionics is defined to be:

‘The science of creating artificial systems or devices that can work as parts of living organisms’

(Definition of bionics from the Cambridge Advanced Learner’s Dictionary & Thesaurus © Cambridge University Press)

By making it possible to replace whole organs to mimic that of the real ones, whether it be your eyes, ears, legs or even your brain, we are now able to massively improve the quality of life of those who have lost limbs, so they can freely go about day-to-day life like they once did before.

Bionic Integration with Hugh Herr

In an incredibly moving TedTalk in 2014, Hugh Herr explains how bionics shaped his life. After losing both of his legs in a climbing accident in 1982, technological innovation allowed Herr to cure his own disability with optimal support, and in doing so, discovered the beauty of the flexibility in the artificial part of his body.

Through mathematical models, imagining and robotic tools, his bionic limbs were able to attach to his true body through synthetic skins with stiffness variations mirroring his underlying tissue biomechanics. To add to that, through bionic propulsion allowed the bionic limb to emulate normal muscle function, or even at an advanced level. This was critical for Herr and his athletic ability. To add even further, electrodes measuring electrical pulse of muscles communicated to bionic limb so if he thinks about moving, he moves!

He took advantage of this flexibility and returned to climbing, eliminating his disability. Herr, as the head of the MIT Media Lab’s, is now building the next generation of bionic limbs and robot prosthetic that resemble biological materials.

The moral of the story is, despite losing both of his legs, the importance of bionics and the characteristic ability to use electromechanics attached to the body and implant them inside the body meant that Herr’s quality of life only flourished. He did not let it diminish him, nor destroy his self-wholeness. This should be the hope for all those who suffer from a similar story.

What do the ongoing advancements in ‘Bionics’ mean for the future of ‘disability’?

In decades to come, if the progress continues, we could see a world free of disability. Where a hand could have additional functional fingers, or an eye could improve low light vision and zoom in to make faraway objects clearer, or the paralysed can walk primarily based on artificial neural networks and swarm intelligence.

While artificial limbs are not nearly as good as a natural one,  someday, we might advance to the point where artificial limbs might become superior to natural ones, available to everyone that needs it.

That being said, even those with normal physiology have appeared to use exoskeletal structures following the same principles to augment things like human walking, running, climbing etc. In doing so, it reduces metabolite cost and suggests that we are going into a time where these designs can make us stronger, faster and more efficient

To conclude…

Every being on this earth deserves a right to a life free of disability and full of ability at basic physiological function. The ongoing advancements of bionic technology show that as a human race, we are dependent on its growth to optimise our living. So perhaps humans cannot be disabled, but technology?