Core Problem 3

• What role has animal-based research played in medical, veterinary and environmental research?
• Is the use of animals in basic research justified?
• What is the community's view of animal use in research?
• Arguments against the use of animals
• Refinement strategies
• End-points
• Recognition of pain and distress (general and species-specific)
• Relief of pain and distress

In order to justify the use of animals in research or teaching, it is necessary to establish a case for the potential benefits of that research or teaching.

This requires: 

1. Assessing the probability that the outcomes of the proposed study can be achieved, and
2. Evaluating the contribution that these outcomes will make to addressing the questions being asked.

Evidence to support the likely benefit and relevance of the scientific outcomes, of necessity, will be based on historical experience.

We should be mindful that this decision also involves an evaluation of the importance or value to society of the particular scientific question being addressed. It is likely that there will be a range of views about the benefits of each project.

The decision as to whether or not there is benefit in undertaking a particular project involving the use of animals will be influenced by both scientific and broader community values. This problem explores the kinds of information which are likely to influence such decisions.
 
This problem explores the evidence for and against the value of animals in advancing human and animal health and discusses community views about animal research. Then problem also considers situations where the use of animals is justified and how strategies may be employed to limit the negative impact of procedures on the welfare of those animals.

Since the middle of the nineteenth century we have seen significant improvements in human health and in our understanding of biology and the processes of disease. As a measure of these advances, it has been estimated that during the twentieth century, the life expectancy of Americans increased by 25 years. These advances have been brought about through a variety of strategies, improved hygiene and nutrition being key players, and experiments using animals have played a significant role. There are numerous examples of where studies involving animals played an important role in scientific and medical advances awarded the Nobel Prize.
 
Many of the important advances in biological and medical knowledge have been initiated by a chance observation or discovery - to be valid, any ‘new’ idea must stand up to critical scrutiny and rigorous testing. In many instances, this testing will involve experiments on animals or humans, or both. Advances in our knowledge of biology and medicine are brought about through bringing together information from a variety of sources, including data from human and animal experiments, epidemiological studies, in vitro experiments (organs, tissues, cellular and molecular) and computer simulations and modelling; both contemporary and historical data may be used. There are many ways in which new information can lead to a ‘medical advance’ - perhaps the chance observation can be the ‘missing link’ which, when combined with existing knowledge, provides new insights or, a new discovery leads to a different approach to a particular question and directs a new avenue of research.

The stories of aspirin, insulin and cholera have been selected to illustrate the varying importance of animal experimentation in the advancement of knowledge and medical science.

On 2 June 1763 Rev Edward Stone read his "Account of the Success of the Bark of the Willow in the Cure of Agues" to the Royal Society of London. He had noted that willow trees grew in wet areas, where fevers are also common. He suggested that Providence would be expected to have placed a remedy for the disease nearby. More than 100 years later (1874), MacLagan showed that salicin, contained in willow bark, had analgesic and anti-inflammatory effects as well as being able to reduce fever. It was also shown that salicylic acid, released from salicin, was the effective compound.

By 1877 sodium salicylate, produced commercially, had been introduced into medicine, but was unpleasant to take and induced nausea. Research was initiated in 1895 to study derivatives of salicylic acid in the laboratories of Friederich Bayer, a dyestuff manufacturer in Germany. Acetyl salicylic acid was found to be an acceptable and effective analgesic.

All this was achieved without the use of animals. In fact, at this time knowledge of pain mechanisms was scant and, in the first half of the century, tests to detect analgesic activity were quite unreliable. At the time, it was thought that aspirin acted in the central nervous system.

In the 1960's, studies of the effects of aspirin in animals began to reveal interesting new properties of the drug. It appeared that the effects of aspirin on inflammation and pain were mediated locally, and not in the central nervous system. In the following years, details of the ability of aspirin to prevent the formation of chemicals that the body produced in defensive reactions were revealed in the results of animal experimentation.

One of the leading researchers in this area was John Vane, who eventually received a Nobel prize for this work. As well as leading to the understanding of the mechanism of aspirin, these experiments were also invaluable in understanding the phenomena of pain,  inflammation and fever.

Today, as a result of experiments in isolated cells, organs, whole animals and humans, we understand the complex pharmacology of this very old drug and have found new, life-saving uses for a "common household remedy". For instance, as a result of experiments in animals, we know that low doses of aspirin have a beneficial effect in reducing clot formation and patients at risk show an impressive decrease in heart attacks if they take 150 mg (half of a conventional tablet) of aspirin each day.

Cholera was a major killer throughout the world. It is an acute disease, associated with severe diarrhoea, which can quickly lead to dehydration and death. It is thought that cholera first appeared in India during the 4th century BC. Although it frequently presented as a significant problem for the British army in India, cholera was not a health issue in Europe or England before the 19th century.

The first serious outbreak in Europe was in the early 1830’s when the disease spread from India, through Russia, to Europe, England and North America.

Subsequent epidemics occurred in Europe and England in 1840’s, 50’s and 60’s. In each instance, the outbreak had spread from India or Asia. The 1863-72 pandemic was the last to have a serious effect in Europe or England. However, there were two further epidemics in India and Asia before the end of the century. When cholera was first seen in Europe and England, neither the cause nor an effective treatment were known. The disease had a marked impact. In England alone, 53,000 deaths were recorded during the 1840’s outbreak and it is estimated that millions of people around the world were killed by this disease during the 19th century. Towards the end of the century, despite major outbreaks in other parts of the world, a rapid decline in the incidence of cholera in Europe and England was brought about, primarily through major developments in public health policies which limited the spread of the disease.

By the 20th century, the importance of sanitation in the effective control of the disease had been widely accepted and formed the basis of major changes in public health policies. As a result of these developments, in countries where there is a supply of clean water, cholera is not a serious health problem. However, when the water supply becomes contaminated, either due to poor sanitation or breakdowns cause by natural disasters, such as major flooding and earthquakes, cholera is a risk.

In many countries, where there is no supply of clean water, cholera is still a major health problem. In the early 1960’s a pandemic started in Indonesia. By the middle of the decade it had spread to eastern Asia, India, USSR, Iran and Iraq. In 1970 cholera was seen in West Africa for the first time in over 100 years and in 1990 it appeared in Latin America, where it had also been absent for more than a century.

In 1998, the World Health Organisation (WHO) recorded 293,121 cases of cholera world-wide with 10,586 deaths.

Today, the management of dehydration with fluids and electrolytes is the first line of treatment. In severe cases, antibiotics may be required. The only cholera vaccine which is widely available is of limited value in the management of this disease; it only provides limited protection for a short period and therefore is only helpful to give some protection against acute exposures.

However, the ability to prevent cholera by simple public health strategies - good sanitation and clean water supplies - has lead the WHO to argue that in this century cholera is “the unnecessary disease”.

The control of infectious diseases - challenges ahead
Many other infectious diseases have similar stories and these relate to both human and non-human animals. Disease which were prevalent at the turn of the century which have been controlled or eliminated include:

*In non-human primates only

**Many of these diseases may be the result of similar causative organisms although they are named differently when they occur in humans and animals

Today, we still have major international health problems for which we do not have an effective means of control or treatment. Malaria is a case in point. Over 40% of the world population is at risk from this disease. There are 300-500 million clinical cases each year, and 1.5 to 2.7 million of these patients die. More than 90% of these cases and most of the deaths occur in tropical Africa. A major international research effort is underway to find an effective vaccine against this disease. Australian scientists are playing an important role in these activities.

To find out more about the fight against malaria and other infectious diseases visit WHO.

Diabetes - the problem

The underlying problem in people with type 1 diabetes, formerly called insulin dependant diabetes, is that the pancreas does not secrete an adequate amount of the hormone insulin which is required for the control of blood glucose levels. Thus the blood glucose levels tend to be high and glucose is lost in the urine. If not properly controlled, damage to a variety of organs and tissues,including the heart ,eyes and kidneys occurs in response to persistently elevated blood glucose levels. Very high glucose levels can be fatal. 
While the outlook for the estimated 800,000 diabetic patients in Australia is quite good, in the years before 1922, the life expectancy for people with type 1 diabetes was less than three years from the initial diagnosis - a worse prognosis than for AIDS patients today.

History

The earliest description of the symptoms of diabetes mellitus was written about 1550 BC and was found in a tomb in Egypt. The word diabetes is derived from a Greek word meaning “going through” or “siphon” and mellitus is Latin for honey, or sweet. The disease is characterised by the sweet taste of the urine and was long believed to be a disease of the kidney or bladder. 

In 1788 Thomas Crawley noted, while conducting a post mortem examination that there were lesions in the pancreas of a patient who had diabetes. However, although others confirmed his findings, at that time there was no evidence that these lesions were the cause of diabetes. The discovery of two cell populations in the pancreas by Langerhans in 1869 did not immediately clarify the link, because only the release of digestive juices was noted and the role of the beta cells remained unknown. In later experiments to investigate the importance of the pancreatic digestive juices in the metabolism of fat Minkowski and von Meering removed the pancreas of a dog in 1889 and noted that it frequently urinated and that the urine contained sugar - that is, the dog had become diabetic. It was thus apparent that the pancreas contained some factor which could protect against diabetes and the work to isolate this factor began in earnest.

Discovery of Insulin

Paulescu, a Romanian physiologist worked for some 14 years and, in 1921, published a detailed description of experiments on animals which outlined all of the physiological and pharmacological properties of the pancreatic hormone. After a number of unsuccessful attempts by others, Frederick Banting and Charles Best showed that extracts from the pancreas lowered blood sugar in depancreatised dogs in 1922. The amino acid sequence of insulin is highly conserved among vertebrates, and insulin from one mammal is usually biologically active in others. The Canadian biochemist Collip succeeded in purifying pancreatic extracts so that they were suitable for use in humans. Very soon after this, insulin, extracted from the pancreas of cows and pigs, was used successfully to lower blood sugar in diabetic patients.

The potency of the insulin extracted from biological sources needed to be determined before the samples could be used clinically. This was done in rabbits. With the introduction of recombinant DNA technology, it is now possible to manufacture human insulin. Thus, isolation of insulin from pigs and cows and biological assays of the material are no longer necessary. It should be noted, however, that it was necessary to test the first batches of insulin produced in this way for biological activity - and this was done using animals.

Current treatment - the way forward

 The clinical effectiveness of insulin treatment was vividly demonstrated by the increase in life expectancy for diabetics from less than three years to more than 26 years from diagnosis. The availability of insulin has clearly revolutionised the lives of diabetic patients (including diabetic animals). However, patients need to regularly administer the drug by injection and, even then, complications of diabetes occur in the long-term. So the drive for research into a better management option for diabetes remains.

One of the first patients to receive insulin, the young girl made a remarkable recovery and survived to about 74 years, when she died of a heart attack.

It is generally accepted that the most effective way to treat diabetes is to establish normal pancreatic function and current research is directed towards transplantation procedures. Transplantation of whole pancreas (often in combination with a kidney) has been developed and refined using dogs and requires the use of immunosuppressive drugs, to avoid rejection by the host.

Some of the current research, using dogs, pigs and monkeys, is aimed at developing methods for transplantation of insulin-secreting pancreatic cells. Experiments in mice also indicate that transplantation of insulin secreting non-pancreatic cells, such as liver cells, transfected with the gene for insulin is an effective alternative approach.

The health and productivity of our farm livestock very much depends on good nutrition and disease prevention. Most of the advances in our understanding of nutrition occurred in the 20th century. Prior to that, the general view was that it did not matter what animals (including humans) ate as long as it contained adequate energy and protein. It was not until the early 1920’s that the importance of dietary elements began to be recognised. The results of animal studies have played an important role in our present-day understanding of the role of nutrition in health and disease.

Disease prevention strategies are essential to maintaining herd health. The efficacy of vaccination as a protection against pathogens was first demonstrated in animals. Today, through vaccination, we can protect animals against at least 55 infectious diseases. This is of benefit for the health and productivity of cattle, sheep, poultry and pigs -animals which provide us with food and fibre. Our companion animals (dogs, cats and horses) and wildlife also benefit.

There are many examples of how new knowledge, treatments or techniques which have been developed for humans are now being used to benefit animals: antibiotics and vaccines are obvious examples. Other examples include advanced surgical techniques (eg orthopaedic implants, transplantation and cardiac by-pass) which were developed using animal studies, then, applied in human medicine and are now used in veterinary medicine. Knowledge of reproductive physiology and techniques developed for application of IVF in humans, are now being applied to breeding programs for endangered species and to control of feral animal populations.

How important is basic research?
One of the critical issues when we look to the justification of the use of animals in a particular project is the predicted benefit from that study. When a project is clearly directed towards solving an identified problem, it is possible to show the link between the results and the predicted outcomes. However, the exploration of ideas in an attempt to understand basic mechanisms, rather than for a directed application, provides the building blocks which make advances in knowledge possible. When deciding whether or not the use of animals is ethically justified in basic (exploratory) research, two important issues should be considered:

1.  Should we value knowledge for its own sake? If we do, then the acquisition of knowledge is recognised by society as a benefit.
2. Can we show how valuable the application of basic research has been in the advancement of human and animal health?

As a number of the examples in this Problem have shown, advances in our understanding of biology and the processes of disease have occurred through bringing together information from a variety of sources. In many instances, the scientist may have no way of predicting the relevance of the results of a particular experiment to future developments. For example, when in 1909, Peyton Rous inoculated tumour cells from one chicken into another and demonstrated the relationship between tumours and viruses, little did he realise that his studies would be the springboard, some sixty years later, to major advances in our understanding of the development and treatment of cancer. Following the discovery of the interaction between tumour viruses and genetic material in the 1970’s, today we are developing gene therapies to treat a number of cancers.

Also, we should recognise that technological advances have often played a key role in new discoveries and the development of new treatments. For example, molecular biological techniques have opened opportunities to study cellular processes at a level not previously possible and the engineering of new biocompatible materials has played a critical role in the advancement of cardiac surgery and orthopaedic implants.

Not all basic research will lead to new discoveries and it is reasonable to ask what is the probability of such studies being applied to solve a problem in the future. One investigation which sought to evaluate the impact of basic research in ten key clinical areas concluded that in approximately 40% of studies which were later judged as being essential for clinical advances, the scientists had not directed the research to specific clinical applications. This is an indicative figure only, but it is probably a reasonable guide if we ask whether or not basic research involving the use of animals is likely to result in some improvement in the health and well being of humans or animals in the future.

Those who voice opposition to animal experimentation do so for a number of reasons. As well as the philosophical objections to using animals in this way, it is argued that animal experiments should not occur because results are misleading.

Of particular concern are the claims that incorrect evidence obtained from animal experiments has put at risk medical advances. Examples given include the conclusion of scientists in the 1960’s that, based on studies on animals, inhaled tobacco smoke did not cause cancer. 

Critics cite examples to show that animal testing has not detected the risk to patients of taking a particular drug - thalidomide being one case in point.

The significance of animal experiments in both the treatment of cholera and the discovery of the role of insulin in diabetes has been challenged. Critics claim that animal experiments have made no contribution to the treatment of cholera and that it was not the experimental studies of Banting and colleagues but rather the report of a clinical case by the American pathologist Moses Barron which provided the conceptual breakthrough in the treatment of diabetes.

To find out more about the criticisms of animal experiments, visit the following: 

• New Zealand Antivivisection Society
• American Antivivisection Society 
• Animal aid
• Australian Association for Humane Research
• National Antivivisection Society

As a society, “animal welfare” is a difficult issue for us to deal with, primarily because of the diversity of views which is found in the community. Attitudes range from those who believe we should be able to do what we want to animals to those who believe animals should be treated in the same way as human beings.

Although concern for the welfare of animals is widely held, there are many views as to the implications of this goal when we have to decide whether or not we can subject an animal to certain kinds of treatment. This diversity is most evident when we consider animal experimentation. Nevertheless, the wider community are key stakeholders whose views need to be taken into account in our decision as to whether or not a particular study should proceed. Reports of government inquiries and surveys are sources of information about the views of the community on this subject.

In Australia, in the mid 1980’s, the Senate established a Select Committee on Animal Welfare for which ‘animal experimentation’ was one of the major terms of reference. Its report on this subject, published in 1989, represented a comprehensive investigation involving examination of many hundreds of written submissions and hours of public hearings during which over one hundred witnesses were called. A diverse range of views was represented. The Senate committee concluded that:

“There is no doubt that the majority of the population supports biomedical research involving the use of animals, provided that effective controls are operating to keep the number of the animals and the level of pain and distress to a minimum.”

More recent data on attitudes in the Australian community are not available. A 1999 survey in the UK, published in New Scientist (May 22) showed that people were prepared to carefully weigh the pros and cons of an experiment and that the level of suffering and the species involved were determining factors.

These reports highlight the significance of the 3R’s as strategies to minimise the risk to animals - Refinement of techniques is essential to ensure minimum impact on animals which have to be involved.

There are some circumstances where, through legislation, the community has put special restrictions in place. The use of animals to screen cosmetics has been banned in a number of Australian states and, in New South Wales, Ministerial approval is required to conduct toxicity testing when it involves the deliberate death of animals. The Community, also has expressed concerns about the use of certain species - dogs and primates being of particular concern.

In contrast, in our commitment to protect the environment from hazardous chemicals and degradation and to sustain and protect biodiversity, the Community is seeking outcomes which will require more research using animals. Governments have identified that research in these areas is needed and is a key strategy in achieving our goals.

Remember, Refinement as defined by Russell and Burch is -

“...any decrease in the incidence or severity of 'inhumane' procedures applied to those animals which still have to be used."
 
There are two key issues:

• First, you need to be able assess the impact of any procedure or condition on the well-being of the animal (refer to discussion in Problem 1) and
• Second, you need strategies to eliminate or minimise that impact.

To achieve these objectives, you need to be able to recognise and relieve pain and distress.

Refinement - What will be the impact of the proceedure in your experiments?

To avoid or eliminate pain and distress, it is essential that you consider:

What is happening to the animals?

What will be the effects?

How will the animals be monitored?

How will the effects be minimised and end-points set?

When they are involved in a scientific study, animals may experience pain or distress either

• co-incidentally, in situations unrelated to the experimental purpose but which are identified in the planning risk assessment
• accidentally, when unforseen complications occur (something goes wrong), or
• purposely, as part of the experimental protocol.

In planning an experiment, you need to be mindful of the range of physiological changes which occur in response to an animal’s experience of pain. This means that you must remember that the experience of pain or distress can be a confounding variable in any experiment.

Review the ‘Checklist’ which has been developed by the Animal Welfare Unit, NSW Agriculture and was discussed in Problem 1 when considering the ‘Impact’ of procedures. This list sets out the range of issues which need to be considered when assessing the impact of proposed procedures on the wellbeing of the animals so that strategies to minimise that impact can be developed.

In circumstances where the impact of a procedure is not known, a pilot study is helpful. This allows you to identify the risks and also to establish a protocol to identify problems and implement an appropriate course of action.

Refinement - Can you limit that impact?

There are many opportunities to reduce the impact of experiments on animals. You should consider the following when trying to refine your laboratory procedures: 

• Appropriate use of anaesthetic agents
• Euthanasia
• Blood collection
• Antibody production
• Surgery
• Endpoints
• Handling
• Housing conditions