Research case studies
Below are links to case studies in which researchers* describe how they use animals in their research and what difference the new Biomedical Sciences Building is making to their work.
Dr Liv Hibbitt: Developing gene therapy for familial hypercholesterolaemia, a genetic condition that results in high cholesterol levels and typically early death from heart disease.
Research: Developing gene therapy for familial hypercholesterolaemia, a genetic condition that results in high cholesterol levels and typically early death from heart disease.
Animals used: Mice
Dr Liv Hibbitt: 'Familial hypercholesterolaemia (FH) is an inherited condition caused by a genetic mutation in a protein that takes “bad” cholesterol out of the blood. Those with the condition tend to have high levels of cholesterol, develop artherosclerotic plaques (hardened arteries), and die from a heart attack or heart disease.
‘FH, although often thought of as a rare disease, actually affects around 1 in 500 people. It typically occurs when one normal copy of the gene is inherited from one parent and a defective copy is inherited from the other. It tends to be first diagnosed when someone goes to their doctor after a heart attack in their late 30s or 40s and a genetic test is done. Patients normally die in their 50s.
‘Treatment normally involves statins, drugs that turn up the working copy of the protein to remove more cholesterol. It is also possible to change diet to lower cholesterol, but only around 15 per cent of circulating cholesterol in the body is due to diet.
‘Gene therapy involves using a gene like you would use a drug. We’re not trying to replace the defective gene, but give the body an extra working copy of the gene. The aim is to deliver the gene to the cells in the liver where it is needed.
‘Gene therapy would be particularly appropriate for FH because there are not many existing treatments and they’re not very effective. It’s also a “loss-of-function” disease like cystic fibrosis or haemophilia, where we can hope to introduce a gene that will restore that function. If we introduce a gene to produce more copies of this specific protein, it should start taking bad cholesterol out of the blood again.
‘People have been working on this area for years and years, and two Nobel prizes have been awarded, but no one has got anywhere with gene therapy for FH. ‘The problem is that the amount of the FH protein is carefully regulated according to how much cholesterol there is around in the body. Previous attempts at gene therapy have used gene regulation elements from viruses which result in lots of protein being made. Unfortunately, too much protein triggers the cells to die and levels of cholesterol quickly rise again.
‘We are using the DNA regions from humans to regulate the FH protein in the physiologically appropriate way. These are longer sections of DNA and means a lot more DNA has to be delivered to the cells in the gene therapy. But we are finding ways of doing this.
‘In working towards a gene therapy treatment, we are at the stage where we’re writing a grant to do an animal study. We have got a delivery system that works in cells, ie we’ve done tissue work in the lab. If we give the cells statins, we see more protein produced after we’ve delivered the gene. And if we give sterols, we see less protein produced, as we would expect.
‘We’ve also developed a way of delivering genes to the livers of mice in such a way that we can see them using a special camera. We use a gene from a firefly that glows and the camera is able to pick up the light that emerges from the mouse’s liver. This drastically reduces the number of animals we would need to use otherwise. Previously, we would have had to kill mice at different time points to determine the gene expression. Here we can put the gene in and monitor on a weekly basis without having to kill any animals. It’s really non-invasive – we give an injection into their tummies under anaesthetic, and they’re running around again five minutes later. Rather than use 200 animals, we have used 20 mice to optimise the experiment and find the best possible way of getting the gene in.
‘Now that we have a method that works, we can hopefully move on to a mouse model for FH.
‘We breed and maintain a colony of “knockout” mice (mice with one gene removed) that are defective in the same gene that removes cholesterol from the blood. Although the mice don’t develop artherosclerosis, we are able to tell if the gene has been delivered and is being expressed as desired.
‘Breeding is as much as we do for most of the mice, but a small number do receive an injection under anaesthetic as part of a trial. Some mice are then imaged with a special camera, again under anaesthetic, and others have blood samples taken from their tail at different times.
‘The Biomedical Sciences Building is fantastic for welfare purposes. Any problems, such as animals not getting on or animals being born with cataracts, and I need to be there immediately to sort it out. If there are any animals in distress at all, I want to be there immediately. Previously, my work was divided between three different centres. With one building I am able to visit it daily and look after the animals. Also it is great that the vets are now in the same building offering their support.
‘I am using mice because I have exhausted all other techniques. I have done everything I can in cells and on computers.
‘Once treatments in development move into animals, it is a whole different story and it can’t be predicted how well they will do. For example, we initially started with large vectors (a vehicle used to deliver genes in molecular biology) that worked fine in cells. It turned out it was no good in mice – it didn’t hit enough cells and so not enough protein was produced. Efficient delivery is necessary to see an effect. We didn’t know this until we did the first experiment in animals.’
Dr David Priestman: Understanding and perhaps eventually treating an unnamed disease which causes severe disability and early death.
Research: Trying to understand and perhaps eventually treat a very severe and disabling disease which leads to an early death.
Animals used: mice
Dr David Priestman: ‘I work on a disease that affects a small number of people, but which is devastating. It’s basically a severe epilepsy syndrome with blindness, and affects children from shortly after birth. The children can do very little: they never learn to walk or talk, they can’t hold things, they have to be fed by a tube, and they’re blind; it’s absolutely devastating. But they may survive into their 20s.
‘The only known cases so far belong to the Amish community in the USA, and the condition doesn’t even have a common name yet. The disease, which runs in families, is all to do with compounds called gangliosides, a type of molecule that is important for the brain and nervous system. Due to a specific genetic defect, the people affected can’t produce gangliosides and this has the devastating effects on their brain and central nervous system that I’ve described.
‘There is a mouse model with the same genetic defect as people with the disease. In other words, transgenic mice (mice with a specific genetic alteration) have been created that, like the humans, also lack the gene for producing gangliosides.
‘The interesting thing is that the mice, unlike the humans, are totally fine. There’s nothing wrong with them. That is actually very helpful, because if we can find out how the mouse escapes the disease, we can try and use that as way of treating the human patients.
‘From our research so far, it seems that the mouse manages to produce a different class of gangliosides that humans don’t, which can replace those that would otherwise be missing. The mouse has another ‘pathway’ for producing gangliosides which is an alternative to the pathway controlled by the defective gene. Humans also have this pathway, but it’s not activated. If we could activate it in humans it might be a way of treating them. That is what we are working on.
‘In terms of how we use animals, our experimental mice don’t actually have anything “done” to them. We breed them, they live normal lives, and then we put them to sleep – humanely, of course – at different intervals. After death we remove blood and tissues for analysis such as biochemistry, histology, pathology, and electronmicroscopy. Side by side with the animal work we’re doing, we’re getting clinical samples from human patients biopsies, blood samples and so on - and doing similar sorts of analysis. By doing that we can see what’s going on at a cellular level. It’s through this combination that we’ve been able to establish this different pathway in the mouse that doesn’t appear to be activated in the human, and which could be the route to a treatment.
‘One criticism you sometimes hear about research using animals is that there are differences between humans and animals. Some people wrongly claim that because of these differences animal research is no use. That’s incorrect on two counts. First, there are far more similarities than differences between mice and humans, so in many cases the mouse model replicates the human disease very closely. Second, even where there is a difference, it can also be extremely useful. In the case of my current research, the difference provides very important insights into the precise role of gangliosides in the brain and why their loss causes the human disease.
‘The mice I work with are housed in the Biomedical Sciences Building and I go there regularly for that part of my research. The previous building I worked in was fine, but it was decades old. The newer, purpose-built facility provides even better conditions for our experimental animals. It is much better for all concerned – animals and researchers – when the animals are in one centralised, state-of-the-art facility. The better the standard of the building, the better the welfare of the animals, and the better the science.
‘I’ve always been happy to speak about the animal element of my work. All the work I’ve done has been very closely related to human disease, and the human work and the animal work has always gone hand in hand. I know that what I do is of clinical importance: over my career I’ve seen first-hand how animal research translates directly to making things better for humans.’
Dr John Parrington: Finding a treatment for a type of infertility in men, and understanding fundamental cell biology that could have an impact on diabetes, heart disease and immune problems.
Research: Finding a treatment for a type of infertility in men, and understanding fundamental cell biology that could have an impact on diabetes, heart disease and immune problems.
Animals used: Sea urchins, mice and hamsters
‘Egg activation is really the thing that sets life going. When a sperm fuses with an egg and fertilises it, the sperm introduces a specific protein which sets off a series of calcium oscillations. The protein triggers the release of calcium from stores inside the egg cell in a series of pulses, activating the egg and setting it off on a path towards a new life. It’s a signal that’s essential for life to begin.
‘Some men are infertile because their sperm fail to activate eggs – the calcium oscillations don’t happen. The sperm lack a proper functioning version of the protein involved called PLCzeta and there’s nothing that can be done.
‘One gauge of how many people are affected comes from couples in IVF treatment where a procedure known as intracytoplasmic sperm injection, or ISCI, is used. Here, the sperm is injected into the egg. Two to three per cent of the men will show this type of infertility. ISCI was used in 47% of all IVF treatments in the UK in 2006, or over 20,800 cases. So that’s potentially around 600 couples a year just in this country who find that they can’t have children in this way.
‘Our aim is to make an artificial version of the protein as a treatment. Although we are still at a preliminary stage, we are beginning to work with IVF clinics. As well as a fertility treatment, we could also use our work to try and come up with a contraceptive as an alternative to the pill. It wouldn’t have side effects like the pill, which alters a woman’s hormone balance.
‘Our research began with sperm from mice and hamsters so that we could identify and then purify the protein involved from large sperm extracts. We wouldn’t have discovered PLCzeta otherwise.
‘We’ve since moved on to human sperm and clinical samples. Using antibodies, we’ve been able to detect where the PLCzeta protein is in the sperm. We also have some preliminary data from a patient that may allow us to determine the mutations involved in infertility.
‘We use mouse eggs in all this work on egg activation because they are much more accessible. Human eggs are very precious. Not only must ethical approval be obtained as it a very invasive procedure to obtain eggs, but also those eggs obtained are generally used in IVF to make babies. The fertilised egg never develops after we have injected it with sperm. We only let it go as far as the calcium oscillations we are looking for.
‘Calcium signalling is also involved in controlling insulin secretion, heart contraction, body weight, the immune system, nerve connections, many different processes in the body. In another area of our research, along with others in Oxford, we study the mechanisms that lead to calcium release. If this goes wrong in some way or is imbalanced, it can lead to conditions like diabetes, heart disease, and obesity.
‘There are three different pathways that mediate calcium release in the cells of the body. One of these is well worked out, but the other two are much less well known. We have gone some way to identifying all the enzymes in cells involved in these two pathways and their mechanisms of action.
‘By determining the enzymes involved in these processes, we can get a lot of specific information about the mechanisms of these diseases, perhaps find better ways of diagnosing them, and come up with new ways of treating them. It is very difficult to design and develop good drugs to manipulate these pathways if we don’t know the enzymes involved. It is a necessary first step.
‘We use sea urchins as a model organism for these studies on calcium signalling because their eggs are very large single cells and so are easy to work with. While sea urchin eggs are a fantastic tool, it is still important to study something that is much closer to human physiology and the mouse is an obvious example. We breed “knockout” mice (mice with a single gene removed) with defects in enzymes involved in the signalling pathways. This is essential for modelling human disease.
‘There is no doubt that the Biomedical Sciences Building is better for animal welfare. The cleaner environment for the animals makes a major difference to the animals’ health and the success of our studies. Knockout mice are very sensitive to their environment and need to be free of disease. If you’re studying a model of a disease the last thing you want is animals getting an infection. With the filtered cages in the new building there is less exposure to infection.
‘It is also important for human welfare. Researchers working with animals over a long period of time can develop allergies. Since the mice are in filter boxes, this will protect the people working with them too. This is incredibly important. Occupational health is a major concern too.
‘We do all we can to use as few animals as possible. We use recombinant proteins in bacteria, culture human cells in the lab and test them, and model the structure of proteins like PLCzeta or drug targets on the computer. But to understand processes at the level of a whole organism, it is still necessary to use animals and test predictions in an animal system.’
Professor David Gaffan: Determining the processes in the brain that result in loss of memory and memory disorder, a very distressing symptom common to many types of dementia and human neurological disease.
Research: Determining the processes in the brain that result in loss of memory and memory disorder, a very distressing symptom common to many types of dementia and human neurological disease.
Animals used: Primates
Professor Gaffan: ‘Problems with memory are often a symptom in early Alzheimer’s disease. They are also a symptom in the early stages of other kinds of dementia. In fact, memory disorder is a frequent part of human neurological disease.
‘There are currently 700,000 people with dementia in the UK, and there are expected to be over a million people with dementia by 2025.‘These diseases are extremely distressing for the patient, but we should also never underestimate how much stress it puts on the family. As memories are lost, people lose the ability to maintain social connections. It’s impossible to have discussions about when a daughter visited yesterday, for example, when there is no memory of that visit.
‘Spouses and family members will describe it as being “like having a non-person in the family”, or “It’s like having a corpse in the room.” It’s because it’s impossible to have social contact with them.
‘It is this traumatic nature of memory disorder that provides the justification for research.
‘We’re interested in deciphering the disease process in the brain, so that we can connect changes in the brain with the symptoms of memory disorder.
‘We need powerful methods to achieve this because, as you’d imagine, diseases are a messy business. In vascular dementia, there can be more or less random damage in the brain. Out of all the changes that occur, which of them cause the memory loss? It’s an open question, but by looking at each component of the disease we can begin to see which of the changes are involved in impairing cognitive abilities and memory.
'There are a number of ways to advance our understanding. We can look at the neuropathology of human patients (studying tissue samples from the brain after death). Rodents are also widely used and their brains are well understood in many ways. You can get a lot of information about rodent memory and see what happens when changes are made.
'But there is a small niche – small in terms of the number of researchers working in the area and small in terms of the number of animals used – involving questions that you can only ask and answer in macaque monkeys, questions that you either can’t ask or can’t answer in humans or mice.
‘It’s down to the fact that monkey brains are much more similar to human brains than rodent brains. One example is the prefrontal cortex area. The prefrontal cortex is very much bigger in primates than in non-primates. The spectacular intellectual powers of humans are in the main down to our large prefrontal cortex, and a monkey has a lot more prefrontal cortex than a rodent.
‘Another example involves a neurotransmitter called acetylcholine. There are a relatively small number of neurons in the brain that produce this neurotransmitter, and they degenerate early on in Alzheimer’s and are strongly correlated with memory disorder. There is a very different arrangement and organisation of these neurons and their connections in humans and other primates from rodents. That severely limits the amount you can learn from rodents.
‘We’ve recently been able to gain new insight into amnesia. There are two types of amnesia: loss of the ability to form new memories (anterograde amnesia) and loss of the ability to recall memories (retrograde amnesia). Both are normally seen together in humans. In order to improve our knowledge of human response to brain injury and disease we’d like to understand the mechanisms behind amnesia much better.
‘It’s clearly easier to measure anterograde amnesia in humans. Retrograde amnesia is a different matter, as you can’t know who is going to develop amnesia in advance and measure their memories before it occurs! But you can do this in animals.
‘We can train a small number of animals over a period of anything between six months and two years to do clever things on a touch screen. We can test their visual memory – ask whether they remember photos of objects, recognise photos of real objects they’re familiar with, pick out remembered objects from complex scenes, etc. All of this is done for food rewards.
‘The best way to show this is done in an entirely humane manner is to point out that these tests are not regulated by the Home Office. The Animals (Scientific Procedures) Act covers everything that has the potential to produce pain, harm or distress. The memory tests we use do not produce these effects and so are not regulated by this act.
‘After this period of training, we introduce some change to brain function. This is done in a surgical operation under general anaesthetic with pain relief and care of the highest possible standard. A small set of neurons is removed by its location, or by a specific nerve chemistry type.
‘On return to the social group, the monkeys then resume the original memory tests on the touch screen. We can then measure how much memory they retain from before, and how fast they acquire and store new information. At the completion of the research, the primates are humanely euthanised and some brain tissue samples analysed to see what has changed.
‘We’ve shown anterograde and retrograde amnesia are quite sharply differentiated and located in different parts of the brain. This is an important result for learning about memory disorder.
‘The new Biomedical Sciences Building is working very well. The monkeys have much more room to play and climb. More space enables the social groups to be more stable. That’s really important because social groups are key for the happiness and welfare of the monkeys. In addition, this provides better stability for behavioural tests of cognitive ability.
‘There are other benefits too. The sound proofing of the rooms in which the monkeys do the memory tests means the sessions are less disrupted by external noises and therefore the results are more reliable. We are also able to use vastly more sophisticated equipment, including an MRI scanner. This machine helps in detecting changes in brain activity in a non-invasive way. It’s one example of refining the experiments we carry out to improve the welfare of the animals.’
Professor Matthew Rushworth: Identifying the brain processes involved in making decisions and taking actions to learn what happens when they work properly and what happens when they go wrong, eg after a stroke or in psychiatric conditions.
Research: Identifying the brain processes involved in making decisions and taking actions to learn what happens when they work properly and what happens when they go wrong, eg after a stroke or in psychiatric conditions.
Animals used: Rats, primates
Professor Matthew Rushworth: ‘We try and understand the basic processes in the brain that allow us to make decisions or choose a course of action according to what’s happening around us.
‘For example, just coming into work in the morning involves making many decisions based on information in the environment – looking at the traffic lights and deciding whether to stop or drive through.
‘Then there’s also a different type of decision in which there is nothing telling you what to do, and you have to weigh up the potential courses of action and make a judgement about what’s most beneficial.
‘Each decision type involves different brain structures and connections. And these processes can go wrong.
‘There are psychiatric conditions, such as schizophrenia and depression, that affect the way we read our environment and the courses of action we take as a result. In depression, you may be inclined to read the costs and benefits of a possible course of action differently. The result would be that you didn’t engage in activities that others would consider meaningful and rewarding.
‘By understanding the basic mechanisms of how decisions are made in the brain and how they work properly, it can guide our interpretation of what happens when they’re not working properly.
‘Answering these fundamental questions about brain processes is necessary in order to interpret changes in patients with brain damage. In those that have suffered stroke-induced brain damage, many find themselves unable to make movements in parts of their bodies. We want to know why that failure occurs. And why do some people fail so dramatically while others recover a great deal of movement?
‘The brain is a mosaic, with different areas doing different tasks. If a tile is lost, for example a tile that’s involved in movement, there is some degree to which other tiles can take over that role. The differences in recovery from stroke appear to arise from differences in the amount to which alternative tiles can take over from the missing tile.
‘We’re working with other groups in preclinical research to see if ways can be found to encourage those other tiles to take over lost function.
‘In the mosaic-like brain, we want to identify which areas are important for which function, the types of connections that are made, the information that’s contained in each area, and that area’s influence on other parts of the brain.
‘While part of this work involves animals, a lot of research is done with humans. We can look at how brain processes work normally by putting humans in MRI scanners and recording activity in different areas of the brain when the volunteer is making decisions.
‘We can also use a technique called transcranial magnetic stimulation (TMS) in humans to stop particular areas of the brain from working for a very short time and see what effect this has. TMS applies a pulsed magnetic field to areas on the outside of the head for a few milliseconds to interfere with the normal electrical signals in the brain.
‘Through careful and repeated measurements of the responses to the tasks we give people, we can identify the signals and brain mechanisms involved. However, it is impossible to access some brain areas – deep areas of the brain or areas where the jaw or nose would get in the way of the TMS – or it may be unsafe to disrupt brain signals for long enough to get a reading. Here it is necessary to move to animal models.
‘We have developed behavioural tests for both rats and primates to understand their decision-making processes. With rats, it’s running around mazes, while monkeys are trained to respond to images on a touch screen.
‘The monkeys are trained to touch a monitor that has been specially set up for them in return for food rewards. Motivated by the food, they can learn to touch the right of the screen when a green circle is shown and the left of the screen for a red circle, for example. If they don’t receive the food, they’ll be given food afterwards in their home cage. We don’t think that the touch-screens routines are unpleasant for the animals, and in fact they seem to like doing them.
‘After a period of months of learning the tests, we remove a limited amount of brain tissue under anaesthetic. A full course of painkillers is given under vet guidance in the same way as any human surgical procedure and the animals are up and about again within hours.
‘We don’t introduce gross damage as happens to a human who’s had a stroke. Stroke affects many areas of the brain, which makes it so catastrophic. We would rightly not be allowed to make such gross damage in an animal. We focus on one small area of the brain in a controlled way that leaves no immediately observable change in the rat or primate. Only through the sensitive behavioural tests we have set up can we see what effect this area has in decision-making brain processes.
‘The Biomedical Sciences Building has made a great difference because of the excellent conditions in which the animals are kept.
‘The animals take part in these behavioural tests for at most about an hour a day. Most of the time they are in their housing units where they live. And these got much better with the move to the Biomedical Sciences Building.
‘This might seem a minor change. Most outside concern tends to be about whether something invasive is done to the animals, but any procedure, invasive or not, is controlled very strictly. Our major worry instead is the day-to-day, round the clock welfare of the animals, which totally depends on the environment in which they live and the other animals they share it with.
‘The Biomedical Sciences Building has been better and easier for housing animals together. It has been very beneficial indeed.’
Professor Frances Platt: Searching for new treatments for a set of inherited diseases that result in neurodegeneration and early death.
Research: Searching for new treatments for a set of inherited diseases that result in neurodegeneration and early death.
Animals used: mice
Professor Frances Platt: ‘Lysosomal storage diseases are a set of 50 different disorders, the vast majority of which affect the brain. They most often result in a relentless and devastating decline in neurological function and early death, often in infancy and childhood.
‘While individually rare, together they affect as many as one in 5000 live births.
‘They are genetic diseases that occur when a child inherits a mutant gene from both parents. The child will have a deficiency in an enzyme that causes a particular type of molecule to build up in the cells of the body. The molecules are stored in parts of the cell called the lysosome, which gives the diseases their descriptive name: lysosomal storage diseases. I study a sub-group of these diseases in which fatty lipids that have sugars attached to them are stored.
‘Those with the disease tend to be born completely normal, but children may then begin to fail to meet certain developmental milestones as they get older. There can be a very rapid build-up of the molecules in some people leading to disease in early childhood, and there are also milder forms of the disease that don’t develop until adulthood. These adult-onset patients develop symptoms in their 20s, 30s, 40s, or 50s.
‘The diseases are hard to diagnose and being referred to the right person, often a paediatric neurologist, is key. Unfortunately, because of the range of possible symptoms and the variation in severity of the disease, it can take several years for a correct diagnosis.
‘We don’t understand all the factors that cause the differences in the age of onset of the disease, but progression of the disease is relentless once it begins. We don’t even understand what the molecules normally do in cells (what their function is), or why the build-up leads to such devastating effects in the brain of people with these disorders.
‘My research group is interested in how the accumulation of these sugar-lipid molecules triggers the cascade of events that leads to the disease, and how we can devise new therapies to combat this.
‘We found that a drug called miglustat stops cells from making the problematic molecules in the first place. If the cell cannot make as many of these molecules, then the build-up stops or at least takes longer to occur. The hope is that the disease will be stopped or slowed in its progression.
‘We started our experiments in tissue cultures in the lab, before moving on to mouse models of lysosomal storage diseases, and showed that the lifespan of the mice was extended by 40 per cent. Full-scale clinical trials with the backing of clinicians and pharma companies then demonstrated clear-cut results. We are certainly impacting the disease with this drug, and it is now approved in the EU and US for treatment of Gaucher disease. A clinical trial of the same drug in Niemann-Pick type C disease patients has recently shown that this drug is disease modifying in this severe neurodegenerative disorder.
‘Having this drug also allows us to go back and dissect some of the cellular changes that go on in these diseases. In Niemann-Pick disease type C, we have been able to show that the disease affects how the cell uses calcium.
‘This gave us a new therapeutic approach to try. We are now looking at curcumin, a natural product from turmeric that is used in curries, which elevates the level of calcium in the cell. Niemann-Pick type C mice given curcumin do better than they would otherwise. We are now moving towards working with clinicians to show whether curcumin has a benefit in the human disease.
‘It may be that combination approaches are the best way to help patients with these diseases. It may be possible to combine drugs like miglustat with anti-inflammatory drugs that mitigate symptoms, and natural products like curcumin that target a different aspect of the disease.
‘The mouse models of these diseases have either spontaneously occurred due to mutations in healthy mice or have been modified to have the same genetic mutations as in the human disease. In this group of neurodegenerative diseases, the mouse models provide very good mimics of the human conditions and have similar clinical features.
‘In the trials of new therapies in the mouse models, one group of mice will receive no treatment and another will receive a drug orally (there are no invasive procedures). We have developed a set of behavioural tests – for example that look for the mouse’s ability to do tasks, their coordination and exploration – that are a sensitive measure of the stage of disease. This means we don’t have to kill mice to follow disease progression, and groups of five mice can give an answer rather than much larger groups. When the mice get close to dying, we humanely put the mouse to sleep then take tissues for biochemical analysis.
‘If there was an alternative to using mice, we would use it. A lot of work is done in tissue cultures for example. But we could not show a therapy worked without mice. In a typical paper from our group, only one figure will show the result of work with mice while nine out of ten will involve cultured cells.
‘There are lysosomal storage diseases that affect animals too – sheep, cows, dogs, cats, deer, even emus – so there is veterinary interest in these results. There are now five or six companies looking at developing therapies in this area.
‘The new Biomedical Sciences Building has made an enormous difference to our work. It is better for the animals’ welfare and care, and better for the science.
‘With the new building, animals are housed in state-of-the-art facilities. Vet care and supervision is now all in the same place, so that all the people with animal care, welfare and procedures knowledge are right there with you to offer advice on best practice.
‘While our previous building was fit-for-purpose, it wasn't ideal. Things are much better now since the move to the new facility.'
Researcher V: Understanding why the heart fails, as well as the effect of exercise and diet on heart disease and diabetes.
Research: Understanding why the heart fails, as well as the effect of exercise and diet on heart disease and diabetes.
Animals used: rats
Researcher V (prefers to remain anonymous): ‘We’re interested in why the heart fails. Heart disease is still the biggest killer in the Western world, and it’s getting worse. What’s more, we still don’t know the changes that occur in heart failure.
‘We’re also interested in the effect of exercise and diet on heart disease and diabetes.
‘We mostly use magnetic resonance imaging (MRI) techniques to look at both human patients and rodents because we can see the function of the heart and any changes in its metabolism non-invasively, ie without affecting, operating on, or harming the patient or animal.
‘The heart normally uses around 70% fatty acids and 30% glucose (a sugar) as its energy source. Parts of the heart cells called mitochondria burn up this fuel with oxygen to provide all the energy the heart needs to beat and pump blood around the body.
‘In heart failure, it is thought that the heart begins to use more and more fatty acids for fuel and the mitochondria don’t use oxygen as efficiently. The heart begins to dilate, or get bigger, to compensate. At some point, as the heart becomes overloaded with fatty acids and lacks oxygen, specific protein molecules “uncouple” the mitochondria and no more energy is produced. These are called uncoupling proteins. The result is the heart is starved of both oxygen and the energy to pump, and it fails.‘But this is all theory; it hasn’t all been tested.
‘We’re looking at normal people as well as those with heart disease. For example, we have put people in a hypoxic (low oxygen) tank and looked at mountaineers going up Everest to understand the changes that occur when the heart is deprived of its normal amount of oxygen. We have also infused volunteers with fatty acids to see if that does lower the heart’s energetics.
‘You can also look at the effect of a high-fat diet – the hearts of normal people quickly look terrible on such a diet, while there is no effect in athletes at all. It shows that athlete’s bodies really are the norm and should be how we all look. It is our sedentary lifestyles that are wrong. We suffer without enough exercise.
‘Exercise turns out to be incredibly important for diabetics and older people. Our work has also helped lead to changes in cardiac surgery. In open-heart surgery, the heart is perfused with glucose-containing solutions so that the heart is not starved of fuel.
‘As well as working with healthy volunteers and patients, we also use animal models of obesity, diabetes, and heart failure to gain more understanding of the effects of diet and exercise on metabolism. This allows us to learn the pathway of chemical changes in heart cells that leads from increased fatty acids to the production of the uncoupling protein molecules.
‘We now know why betablocker drugs work, for example – they stop the effect of the uncoupling proteins. No one knew this before. By knowing the cellular mechanisms that lead to heart failure, we will be much more likely to come up with drugs to combat the disease.
‘We have also been able to show that lowering the amount of fatty acids in the diets of diabetic mice means they are less likely to have a heart attack and more likely to survive. We believe the same is probably true in humans.
‘After a heart attack, there is a dead area of the heart that has been deprived of oxygen. We have been looking at whether novel stem cell treatments could regenerate the dead heart tissue. We have done this in rats to understand whether it is safe and whether it might work.
‘So far, we have shown that adult stem cells from bone marrow are safe but don’t work. Some people have claimed to show that stem cells from the heart itself do differentiate and could provide all the types of heart cells you would need to repair damaged tissue. But I believe we need to understand a lot more about stem cells and their differentiation, and this is our current focus.
‘We have also invented a new food group, a food group beyond those of carbohydrates, proteins and fats that we have called ketone bodies. Ketone bodies are normally made in the liver from fat and are used to feed the brain in the absence of the glucose it would use otherwise (the brain can’t use fat for food).
‘We’ve developed a ketogenic diet that could help treat epilepsy, Alzheimer’s disease and Parkinson’s disease. It’s the worst diet – really unpleasant! It’s all fat and a bit of protein, and you can’t eat carbs. But the cognitive and physical performance of rodents is improved: they run up to 30% further on treadmills and their performance in maze tests is better. We have now gained permission to do a dosage study in humans.
‘As well as working with people with heart disease, diabetes and those who are obese, we do use animal models of these conditions. While the models of obesity are just fed high-fat diets, the models of type I and type II diabetes are bred commercially and we buy them in. Using MRI, during which the animals are anaesthetised, allows us to follow disease progression over time without having to kill so many animals to obtain tissues.
‘We do use surgery to make an infarct and give an animal model of heart disease. We then infuse stem cells through the tail vein to see if this can regenerate the tissue and provide the basis of a novel therapy.
‘The Biomedical Sciences Building offers better care of the animals, and is healthier for both animals and researchers. It is cleaner, handling the animals is easier, and the prevention of infections has been improved. It is just ideal.’
Researcher W: Understanding how the brain develops, both normally and in neurological diseases.
Research: understanding how the brain develops, both normally and in neurological diseases.
Animals used: tadpoles
Researcher W (prefers to remain anonymous): ‘My research group is trying to understand how a nerve cell in the brain forms connections with other nerve cells in the brain, early in life. This process often goes wrong in early development. Many disorders, such as mental retardation, schizophrenia, and epilepsy, involve errors in how nerve cells connect to one another in the early development of the brain.
‘My work aims to find out what the normal processes are and, from that, how exactly they can go wrong. That is of direct use to clinical colleagues who are looking at how to prevent or treat these disorders.
‘In my work I use the tadpoles of a type of frog called Xenopus. Tadpoles can give us a lot of information about the developing brain, for two main reasons. One, we get access to animals very early in development, because the embryos develop outside the mother’s body. We can therefore study brain cells at a very early stage in a way we couldn’t in a mammal. Two, tadpoles are translucent, allowing to look inside the brain tissue of a live animal non-invasively. The ultimate aim of the experimental biologist is to examine phenomena in the intact tissue, where you have all physiological aspects maintained and you can explore the effects of the environment on the animal.
‘A large proportion of what we do uses microscopes to look at behaviour of brain cells in the tadpole. The fact that it’s translucent allows us to do this in a very non-invasive way. By fluorescently marking a particular nerve cell in a tadpole’s brain and then putting the tadpole under the microscope each day, we can generate a time lapse picture of a single nerve cell developing in a living brain. We’re interested in seeing how the structure of the nerve cell is established – as structure is key to how it forms connections – and how “daughter” nerve cells are born from “mother” cells.
‘We also use microelectrodes – tiny brain probes – to record what is happening in a single nerve cell of the tadpole’s brain during visual stimulation. We anaesthetise the tadpole, put it under a microscope, and place these electrodes onto a single nerve cell in its brain. We then present visual stimuli to the animal and record the responses of the nerve cell. Tadpoles can see and respond to very simple visual stimuli like shadows in order to avoid predators. And the responses of the tadpole brain cells involve the same chemical and electrical signals that operate in our brain cells. Therefore, amazing as it may sound, finding out how a nerve cell in a tadpole’s brain responds to a sensory stimuli gives us information that is very relevant to how brain cells develop in a human baby.
‘Our work has characterised some of the signals between nerve cells which change the strength and type of connections between them. At the clinical end of things, the mechanisms we’re trying to understand, and are understanding more, relate to how nerve cells control their own electrical excitability.
‘Epilepsy is a situation where this control is lost. Epilepsy is a tendency to have recurrent seizures or fits, which are caused by a sudden burst of excess electrical activity in the brain. At the moment there is no cure. It affects around one in every 280 children. The mechanisms my colleagues and I are characterising in normal development speak directly to those that go wrong in epilepsy.
‘The main benefit of the Biomedical Sciences Building for our research group is that there is a pool of expertise in terms of technical support. When the building was completed, technicians formerly in different facilities all moved to one place and there is now a concentration of expertise. There are animal technicians in the building who generate the tadpole embryos for us, which frees up researchers’ time to study the results.’
Researcher Y: Use of sensitive behaviour tests to understand memory storage and processing as well as the effect of genetic defects, all of which can inform clinical approaches to human disease and disorders.
Research: Use of sensitive behaviour tests to understand memory storage and processing as well as the effect of genetic defects, all of which can inform clinical approaches to human disease and disorders.
Animals used: Primarily mice, less frequently rats
Researcher Y (prefers to remain anonymous): ‘Memory and emotional responses are abnormal in a number of terrible neurodegenerative diseases like Alzheimer’s, psychiatric disorders like schizophrenia and depression, and genetic conditions like Williams syndrome. It is important to learn how changes in a wide range of behaviours including loss of memory and changes in response to anxiety arise so we can understand more about these conditions and come up with new approaches to care and treatment.
‘The part of the brain called the hippocampus is at the core of memory processing in humans, so it’s of great interest to us. The hippocampus is also part of the system involved in anxiety and response to threats. It degenerates in Alzheimer’s disease and has been shown to be shrunken in people with long-term depression or schizophrenia. It’s also one of the very few areas of the brain where new nerve cells are formed and connected throughout life. So it’s of interest for a number of reasons.
‘We would like to know more about how we store memories. What changes in the connections between our nerve cells in the brain when we store a memory? It is now beginning to be possible to address what those changes are – we can use genetic manipulations to tease out the molecular basis of memory.
‘This is basic stuff, basic fundamental science, but it leads you to think about the clinical connections and about new therapy approaches for human diseases such as epilepsy and Alzheimer’s where these processes go wrong. We sometimes work with human patients with schizophrenia, or study the brain’s responses to pain and its anticipation using imaging methods in healthy volunteers, often through collaborations with other research groups.
‘We are also interested in developing sensitive behavioural tests so that we are able to determine any differences in the behaviour of mice with different genetic make-ups. For example, we are looking at Down’s syndrome mice, Williams syndrome mice, and FOXP2 mice.
‘Down’s syndrome is caused by the presence an extra copy of a chromosome, while Williams syndrome involves a large deletion of genetic material from a different chromosome. Individuals with Williams syndrome are often highly verbal and sociable (one of my colleagues says it’s unusual for her to be around people with Williams syndrome for any length of time and not receive a proposal of marriage!), but typically have a range of cognitive impairments as well. FOXP2 is a gene that is linked to the development of language abilities in humans.
‘We test the learning and memory capabilities of the mice using specially designed mazes or by seeing how they explore. We might see how they respond to new types of food they are offered, or how they react to darkness or brightly lit areas as simple tests of anxiety. We look at how well they cope with the simple tasks of daily living or look at their social interactions. These tests are sensitive enough to show clear differences in the behaviour of normal mice and mouse models of disease or dysfunction, even though there may be nothing immediately obvious to an observer.
‘Mice can be genetically engineered to have changes that mirror those found in humans. The mouse models, as they are known, allow us to learn about the genetic defects, what function the genes have, and are a way to try to answer questions like: could you turn off the extra genetic products to turn off Down’s syndrome, or what genes are responsible for the changes in behaviour observed in Williams syndrome?
‘There is a group of diseases caused by prions – proteins that have taken up a malformed structure and build up in brain tissue, disrupting brain function. The best known in humans is variant Creutzfeldt Jacob (vCJD) disease, which is strongly connected to BSE in cows.
‘We were able to show in behavioural tests with a mouse model of vCJD that a potential treatment that had been suggested for human vCJD didn’t seem to work. It’s very hard to get quick, informative answers like this in humans, but clinical experience since then seems to fit our conclusions. While disappointing, this does show the value of this type of research and the conclusions that can be drawn.
‘We have also shown that if you give an animal with prion disease a compound to activate its immune system, its symptoms rapidly get worse. That is, activating the immune system brings forward the consequences of the prion disease.
‘This seems to mirror what sometimes happens in humans when their immune system is similarly challenged. Our collaborators are gathering data from elderly patients and their families to see if they sometimes go downhill quite abruptly after an event like a bad fall, or suffering from an infection.
‘These kinds of result can have a potential impact in the care of those with Alzheimer’s. If we understand this connection, we may get a completely new take on how important catching flu or breaking bones is to the progression of disease. It may be that giving flu jabs is not just important to avoid infection, but to stay bright!
‘It’s difficult to get quick fixes here and translate this research into novel treatments. They are very difficult complex diseases but there is a huge market of unmet need.
‘The completion of the Biomedical Sciences Building was really important for the good health of the animals. Our breeding colonies for the mouse models are now on an ultraclean level, meaning that chances of infection are extremely small. Having one central facility also means it is easier for lots of different labs from different disciplines to work together and gain much more information.’
Researcher Z: Finding new treatments for Duchenne muscular dystrophy, where currently no treatment is available.
Research: Finding new treatments for Duchenne muscular dystrophy, where currently no treatment is available.
Animals used: Mice
Researcher Z (prefers to remain anonymous): ‘There is no effective treatment for Duchenne muscular dystrophy, the most common genetic form of muscular dystrophy.
‘About 100 boys are born with the disease in the UK every year. While they have no symptoms at birth, by four or five they have difficulty walking up stairs, by age 12 they are in a wheelchair, and they die in their late teens or twenties.
‘The disorder is caused by genetic mutations that result in the lack of a protein called dystrophin which is normally present in muscle cells. The progressive muscle weakness seen in boys with Duchenne muscular dystrophy arises as muscle cells die and cellular debris gradually builds up and accumulates. The dystrophin gene shows the highest mutation rate in humans, meaning that new mutations arise all the time and screening all pregnancies for mutations is difficult.
‘The devastating effects of Duchenne muscular dystrophy really shows the need for new therapies. In the past three to four years some new approaches have emerged, including from my own research group. Next year, the approach that we have developed is being taken into the first clinical trials by a US pharmaceutical company.
‘In 1989, we showed that muscle cells possess another protein similar to dystrophin called utrophin, although it is not present in high enough amounts to replace the lack of dystrophin in boys with the condition. We believed that if we could increase the levels of utrophin, we might have a new treatment approach.
‘There is some evidence that utrophin is present in the early foetus at levels comparable to dystrophin, so we believed it should be possible. We have now shown that we can increase the amount of utrophin and cure the disease in a mouse model.
‘However, we never put drugs in animals unless they have been optimised in cell lines in the lab in the first place. We do as much as we possibly can in cell lines.
‘We began by screening compounds to see if they could interfere with cell machinery in a way that would lead to increased utrophin levels. This was in a spin-out company I formed. Perhaps 30,000 compounds were screened, resulting in around 30 ‘hits’. We then optimised these 30 promising compounds in cell lines, which gave 3 potential drug compounds we could test in mice.
‘Before we moved into mice, the company screened the drugs for toxicity in zebrafish. The development of zebrafish is very sensitive to the toxicity of compounds. This is a relatively new way of screening out potentially toxic compounds, reducing the number of mice used later.
‘By doing all this work, we learnt more about the biology and we have been able to refine what we do as our knowledge increases. At the start, we used ten mice in each trial group. Now we can use six.
‘Now we are moving into human clinical trials, which will start in early 2010. If our first trials show good results, we will then try to raise money for improving the chemistry and optimising the drug, making it a more efficient treatment.
‘The mouse model has a point mutation in the dystrophin gene, but the mouse is only very mildly affected by this. You wouldn’t be able to tell it was affected in any way by watching the mouse alone. Only under a microscope can you see that the muscles are affected. We breed these mice and they are perfectly happy. The drug that we have been testing is injected as we find that gives more reproducible results than when the mice are fed the drug in a food pellet.
‘Before, in our old animal facilities, we didn’t have optimal conditions although they were perfectly fine. This meant reproducibility in experiments was a challenge and we needed to test large numbers of mice. The uniformity of the environment in the Biomedical Sciences Building means there is a low risk of infections, the health of the animals is better, and so the chances of the drugs working is much better. It's been a significant improvement for the animals and for the research.’
*NOTE: Researchers V, W, Y & Z prefer to remain anonymous.