Why are dogs used in biomedical research?
Dogs are used in biomedical research because they have certain similarities with humans which are not present in other animals.
Due to these similarities dogs are only used when other animal models will not achieve meaningful results and this means they are used in a very small percentage of procedures. EU legislation does not allow experimentation on any animal if there is a non-animal method available. Across the EU more than 90% of animal research is done on mice, rats and fish rather than large animals, such as dogs.
EU legislation has some of the strictest requirements for the care and use of laboratory animals – and it has special and justified emphasis on the care and use of dogs.
When is it essential to use dogs in biomedical research?
For a new drug to reach clinical trials in humans, the European Medicines Agency (EMA) and the US Food and Drug Agency (FDA) usually require tests to assess toxicity in both a rodent and a non-rodent mammal to give comparative safety data. The rodent will often be a rat; the other mammal will usually be a dog (although pigs and monkeys are also used).
Many of the procedures are repeat dose toxicity testing, where dogs are used to determine the ‘maximum tolerated dose’, which helps to determine the size of doses for trials in humans.
A small number of dogs are also used for basic research and translational/applied research procedures.
Dogs are used in research on Duchenne Muscular Dystrophy (DMD), which is the most common fatal human genetic disorder diagnosed in childhood - DMD also occurs naturally and is fatal in dogs.
Dogs are especially suitable for cardiovascular studies due to the resemblance in heart connectivity and size to the human heart.
Experiments on dogs led to the discovery of insulin to treat diabetic patients, the development of blood transfusion procedures and the creation of the electrical defibrillator to restore normal heart rhythm.
The efficiency of some new cancer drugs are tested in dogs with the same cancers as humans, as they can have a benefit for both humans and dogs.
See the Animal Research News section below for recent research examples:
Medical treatments for dogs
As dogs have been involved in the development process of drugs, it is often a relatively small step to understand where human drugs might help dogs and to adapt them for veterinary medicine.
Dogs suffer from cancers, heart diseases, diabetes, joint disease and many other conditions. Research involving dogs and other species of animal enables the development of new safe and effective veterinary medicines that improve the health and welfare of animals worldwide.
What is being done to replace and reduce the use of dogs?
EU Directive 2010/63, on the protection of animals used in scientific procedures, took effect in Member States on 1 January 2013. Since then the Directive has enhanced animal welfare standards and mandated the application of Replacement, Reduction and Refinement (‘3Rs’) of research animals, across the EU. The Directive supports research involving animals only when there are no alternative methods, where the potential benefits are compelling, when it is scientifically, legally and ethically justified, and welfare standards are met.
A method has been introduced for keeping muscle cells healthy for two weeks instead of 24 hours, meaning many more compounds can be tested on cells supplied from a single dog.
In educational and training settings dogs have been replaced with a life-like models to learn the surgical procedures and techniques of neutering. These models have realistic organs including a urinary bladder, ovaries, simulated blood and fat tissue.
The effective management of breeding colonies to reduce surplus is a critical area of focus.
Nevertheless, the testing requirements outside Europe often require animal use. Therefore some tests not performed for the European market are required for other markets.
What improvements/refinements have there been to tests carried out on dogs?
Surgical and procedural improvements
Bile Duct Cannulation is the large animal model for investigating the bile elimination of new drug candidates. A less invasive procedure to collect bile from large animals termed ‘ultrasound-guided cholecystocentesis’ has been developed and validated. In this procedure, ultrasound is utilised to guide a needle transcutaneously through the liver and into the gall bladder, allowing for precise bile sample collections. With this refined method, it is now possible to safely and efficiently obtain bile samples from dogs and monkeys in support of drug pharmacokinetic studies without the previous harmful effects.
Different blood sample technique
Arterial blood used to be collected from dogs in a final study, under anesthesia but without revival, via surgery of the large artery in the leg of the animals. However this protocol has now been greatly improved and the arterial blood sample is now taken from the ear artery under anesthesia. Bleeding can be stopped easily without swelling by applying pressure at the site of sampling over 15 minutes and the anesthesia is then reversed. This new protocol no longer leads to the killing of the animal, instead it is woken after the procedure.
How is the animal's welfare regulated?
The majority of dogs are purpose-bred for research at licensed establishments. Dogs are a well-understood animal and it is relatively easy to provide them with good welfare and be confident that they are happy and well-looked after. There are ongoing efforts by the EU to improve dog welfare including improving housing conditions and daily/care handling as well as training dogs to reduce stress during experimental procedures.
According to EU Directive 2010/63:
Dogs shall where possible be provided with outside runs. Dogs shall not be single-housed for more than four hours at a time. A procedure is considered severe if a dog is kept in complete isolation for prolonged periods.
Are dogs rehomed after use?
According to EU Directive 2010/63, in some cases dogs should be returned to a suitable habitat, or rehomed in families, where there is a high level of public concern as the to the fate of such animals. It further states:
Should Member States allow rehoming, it is essential that the breeder, supplier or user has a scheme in place to provide appropriate socialisation to those animals in order to ensure successful rehoming as well as to avoid unnecessary distress to the animals and to guarantee public safety.
Banner image courtesy of: Sanofi.
Beagle image courtesy of: Understanding Animal Research