How animals are helping us towards better Parkinson’s treatments
From the vaccine for smallpox to organ donation, cardiac pacemakers to chemotherapy for cancer, almost every advance in medical treatment has involved animals at some stage in its development. In this blog, we take a look at why animals remain so crucial to Parkinson’s research.
This research has saved and improved the lives of millions of people, as well as contributing to improvements in animal health.
But despite major scientific advances, such as computer modelling, studying brain cells grown in the lab or donated brain issue, animals still have an important role to play in medical research.
How and when are animals used in research?
Animals can only be used if the research is important enough to justify their use and cannot be done using any other method. Researchers must also prove that every effort has been made to:
- reduce the numbers of animals used
- refine experiments to minimise any pain or discomfort
- replace animals wherever possible
These are referred to as the 3Rs and to drive progress towards them forwards, the UK has a world-leading organisation the National Centre for the Replacement, Refinement and Reduction of Animals in Research (NC3Rs). It was established in 2004 and works with the research community to help reduce reliance on animals and to improve animal welfare.
Why do we still need to use animals in Parkinson’s research?
Huge progress is being made which is reducing and replacing the need for animals in many areas of research, including Parkinson’s.
Studying people with and without the condition is an essential part of Parkinson’s research. Major studies involving thousands of participants are helping us understand the condition better than ever before. But while brain scanning techniques are improving all the time, we still cannot see what is going on inside the brain in enough detail.
Studying brain tissue donated to the Parkinson’s UK Brain Bank and others continues to be an essential tool for researchers worldwide. But because the brain cells are no longer alive, you cannot study their behaviour, and tissue usually comes from people in the later stages of Parkinson’s which means it’s hard to study the earlier stages of the condition.
Cells in the lab. Massive progress is being made in our ability to grow brain cells from skin cells which gives us a chance to watch how individual cells behave at extremely close quarters. Cells grown in a dish cannot yet replicate how a whole brain works but we have funded research that aims to develop this technology (see video, left).
Computer modelling. Enormous investment is being poured into developing computer models of the human brain — including a project funded by the European Union costing over €1billion. However these projects are still in their early stages and as yet, computer models that can accurately reproduce the complex working of the human brain are still some way off.
We still need to study animals to help us understand the complexities of how our brains work and how conditions like Parkinson’s develop over time.
Crucially, animals are also still required to test new treatments to make sure they are safe before giving them to people.
“Animal research plays an invaluable and legally mandated part in the development of medicines. It is extremely important — and a legal obligation — for researchers to ensure that promising new medicines are tested for safety and efficacy (i.e. having the intended effects) as far as possible before they are tested in humans.”
How is research involving animals regulated?
The UK has some of the strictest animal research regulations in the world, guided by the Animals (Scientific Procedures) Act, 1986 (ASPA). Research on great apes (orangutans, gorillas, chimpanzees and bonobos) was banned in 1986 and animal testing for cosmetics or their ingredients was banned in 1998. It is illegal to use an animal if there is an alternative non-animal method available, and the expected benefits accrued from the research must outweigh any potential animal suffering.
All research must be carried out in line with strict Home Office regulations. Three separate types of licence are required for animal research or testing:
- one for the institution where the research is taking place,
- one for the researcher carrying out the research,
- and one for the specific research project.
The Home Office employs a dedicated team of qualified doctors and vets as inspectors to ensure all research complies with the regulations. In addition to assessing licence applications, inspectors visit each research establishment on average once a month — often without advance warning.
And they publish annual figures on the total numbers of animals used in research in the UK. You can see the latest figures here.
How are animals taken care of?
Animal welfare is taken extremely seriously. Every institution that conducts animal research is required to appoint a Named Animal Care and Welfare Officer (NACWO), who is responsible for ensuring the highest standards of care for all the animals at the institution.
All animals are checked frequently to ensure that they are in good health and have fresh food and water. The animals also have enriched environments including play tunnels and bedding to keep them active and comfortable.
Any discomfort or suffering is kept to a minimum by appropriate anaesthetics or painkillers.
What Parkinson’s breakthroughs have animals contributed to?
The use of animals in research has contributed to many breakthroughs in our understanding of Parkinson’s and the discovery of current treatments.
Since the 1970s, the lives of millions of people with Parkinson’s around the world have been transformed by the drug levodopa. This acts to partially replace the dopamine that is no longer produced in the brain due to the death of nerve cells.
Research involving animals was an essential step in developing this vital drug. Swedish scientist Dr Arvid Carlsson won the 2000 Nobel Prize for medicine for the fundamental discovery that the chemical dopamine plays a vital role in movement through his experiments in rabbits.
In the 1980s and 1990s, primates played a vital role in the development of deep brain stimulation — a surgical treatment that has dramatically improved the lives of hundreds of thousands of people with Parkinson’s worldwide, and is now also used to treat other devastating conditions including depression, chronic pain and even anorexia.
Today, animals continue to play a vital role in the development of new therapies for Parkinson’s — including new drug treatments and more complex approaches such as stem cell and gene therapies.
Do animals get Parkinson’s?
Animals do not naturally develop Parkinson’s but scientists have developed techniques that can mimic the human condition.
For many years, the principle way to cause Parkinson’s-like symptoms in animals was to use chemicals (such as the toxin MPTP) that selectively cause damage to dopamine-producing nerve cells inside the brain. This technique is very effective for modelling the movement difficulties that people with Parkinson’s experience — such as slowness, stiffness and tremor. But the major disadvantage of this approach is that it causes the damage and symptoms almost instantaneously — which is the exact opposite of how the human condition develops which is very gradual, over a period of years.
This was a major challenge for research, as it meant there was no way to study the early stages and development of Parkinson’s in animals, and made it very difficult to develop and test treatments that could slow or delay the progression.
However, a revolution in the understanding of the genetics of Parkinson’s has led many researchers to move away from these ‘chemical models’ in favour of ‘genetic models’ that more closely resemble the human condition. In these animals, rather than giving them a chemical that produces symptoms overnight, they are genetically engineered so that they carry a genetic variation that causes the damage to occur gradually as they age. This provides a much more natural and realistic model for researchers to study.
Does Parkinson’s UK support research involving the use of animals?
We fund research to develop better treatments and a cure as part of our mission to bring forward the day when no one fears Parkinson’s.
A vital part of this research involves the use of animals. As a charity, we subscribe to the “3 Rs” policy — to reduce, refine and replace the use of animals in research wherever possible.
The vast majority of Parkinson’s UK funded research projects which involve animals use rats and mice.
Fruit flies, microscopic worms, zebrafish are also used.
And in extremely rare circumstances larger animals such as non-human primates may be required.
When researchers apply for funding from Parkinson’s UK we ask for extensive information about any proposed use of animals. They must justify why animals are required and explain why there are no suitable alternatives. Researchers also have to justify the species they wish to use, the number required, the efforts they are making to reduce this number and to ensure the highest possible welfare standards.
During the review process we ask our expert reviewers to carefully assess every aspect of the proposed work including the use of animals. Every application is also reviewed by people affected by Parkinson’s who provide essential input on how important, urgent and meaningful the proposed research is to people living with the condition.
This means we never fund research using animals if there is another alternative, and we only fund projects which hold real hope for improving life for people with Parkinson’s.
Find out more
For general information and resources about the use of animals in medical research:
Understanding Animal Research