Non-human primate research: FAQs

The CNDM houses seven marmosets and 15 macaques*. Non-human primates represent less than 0.01% of the animals used in research at The Neuro. *As of Aug. 24, 2021

The behaviour and disease-associated genes and pathways of non-human primates are closer to humans than rodents. Their brain is more evolved than the rodent brain, and shares anatomical and chemical characteristics with the human brain which are not encountered in rodents. For instance, a marmoset and a rat are both about 350g, but the marmoset brain is seven times bigger than a rat brain, even if the two species are approximately the same weight.

The tests performed aim at studying aspects of human health and disease. For example, tests reveal social aspects of behaviour, brain development, language, visual perception, memory, and movement, and provide insight into the brain function within each of these paradigms.

NHPs undergo a lengthy acclimatization period, designed to minimize potential stress caused by the studies. During these studies, animals’ behaviour may be observed and rated according to specific scales. Animals may also be administered promising novel therapeutics, or undergo experimental procedures that seek to further our understanding of brain physiology, to assess their potential to treat human diseases.

To gain insight into the human brain in health and disease, it is important to use animals whose brain is as close as possible to humans’. In addition, there are important differences between the metabolism (clearance) of drugs and substances between rodents and primates (including humans). As such, determining the metabolism of drugs in non-human primates enables investigators to optimize the drug administration and dosing schedule in humans, thereby minimizing the risk of adverse events to human subjects.

Each procedure or test to be performed needs to be approved by an animal care committee, which includes scientists, veterinarians, animal care technicians and members of the community. During the review process, members of the committee ensure that protocols meet the highest scientific standards, that the number of animals to be used is kept to a minimum, and that all efforts are made to avoid causing any distress to the animals.

Each protocol needs to be renewed on a yearly basis; during the renewal process, members of the committee ensure that experiments conducted during the past year and experiments to be performed in the upcoming year meet the highest scientific and ethical standards.

Lastly, a post-approval monitoring process ensures that the approved studies are conducted with scientific rigour, and in a humane way.

Millions of people are alive today because of the benefits of medical research with animals, and millions more are living longer, healthier lives. Many of the treatments we take for granted today could not have been possible with animals during the research and development phase. For example, the polio vaccine, developed in part after testing on animals, has saved millions of lives after scientists developed it in the 1950s.

Over the past decades, we have witnessed enormous progress in fundamental neuroscience and the biology of neurological diseases through rodent models. However, it is increasingly apparent that the validity of rodent models for neurological disorders is limited, in part because of the sophisticated neural and behavioral manifestation in humans.

For example, social interaction between humans require integrated cognition and comprehension, which are more closely associated with primates than rodents. Non-human primate species, such as common marmosets, possess a high level of cognitive ability and enriched behavioural repertoire, and are closer to humans than rodents in brain structure and circuit connections. Non-human primate models, therefore, are urgently needed to bridge the gap between rodent models and human patients. We anticipate that disease-relevant, non-human primate models of brain disorders will provide an in-depth neurobiological understanding of pathophysiology, and facilitate the development of effective therapies.

In terms of drug development, in the past decades several drugs have failed in high-profile clinical trials for diseases such as Alzheimer’s and Parkinson’s. Some of these drugs were tested in humans because they showed efficacy in rodent models at, in some cases, reversing disease symptoms. However, when advanced to clinical testing directly after rodent studies, severe adverse events occurred in humans, and the efficacy achieved in rodents was not obtained in humans. Such adverse events and lack of efficacy highlight the limitations of rodent models and the potential risks incurred by clinical trial participants when drugs are administered to humans without thorough pre-clinical assessment.

Compared to other types of non-human primates, working with marmosets presents several advantages. Non-human primate species, such as common marmosets, possess a high level of cognitive ability and enriched behavioural repertoire, and are closer to humans than rodents in brain structure and circuit connections. Non-human primate models, therefore, are urgently needed to bridge the gap between rodent models and human patients. We anticipate that disease-relevant, non-human primate models of brain disorders will provide an in-depth neurobiological understanding of pathophysiology, and facilitate the development of effective therapies.  Their small size facilitates housing. They do not carry pathogens that may be harmful to humans. Their rapid reproductive cycle opens the door to more precisely studying the role of specific genes in certain behaviours and diseases. They generate multiple offspring, which facilitates genetic studies by providing larger animal pools.

We hope that research on non-human primates will lead to treatments for various diseases, including Parkinson’s, Alzheimer’s and autism spectrum disorders.

Animals are used in research only when no other adequate methods are available. Researchers at The Neuro use many techniques to study the brain that do not involve animals. Induced pluripotent stem cells obtained from individual patients are a powerful source of neural cells for personalized medicine. Non-invasive cognitive testing on humans, for example, helps us understand basic brain functions that can inform future studies into neurological problems. Other scientists use artificial intelligence and big datasets to find patterns in disease pathology. This can help us understand how diseases such as Alzheimer’s and Parkinson’s progress, and how we can best stop them. Genetic testing using human samples also tells us about the role of genes in neurological disease and how we can target specific gene pathways to treat or prevent diseases.

Animal research in Canada is regulated at the federal level by the Canadian Council on Animal Care. Institutions using animals are held to the same high ethical standards regardless of the species of animal studied. For more information on McGill University’s animal research policies visit: https://www.mcgill.ca/research/research/compliance/animals

Animal research has led to many lifesaving and life-extending treatments for a variety of species, including cats, dogs, farm animals, wildlife, and endangered species.

Humans share many biological and physiological characteristics with animals, and so biomedical research with lab animals advances veterinary medicine as well, helping pets and wildlife live longer, happier, and healthier lives.

Dozens of diseases, from cancer to epilepsy, affect both animals and humans. Through research with animals, scientists can develop treatments and therapies that help both people and animals.