March 9, 2022
Agnes Lacreuse, Amanda Dettmer, & Allyson J. Bennett
Research with monkeys and other nonhuman primates (NHPs) is important for understanding threats to human health that range from Alzheimer’s disease to cancer and diabetes, addiction, Parkinson’s disease, and more. This research is also a fundamental building block for understanding how the brain works, how the immune system functions (and goes awry), and the biology of healthy (and unhealthy) aging. These building blocks of basic science drive scientific and medical advances that benefit humans and other animals.
In the US and other countries, research with NHPs accounts for an invaluable, but small, fraction of all animals in research, roughly 0.5%. Fish, mice, and rats are the overwhelming majority of animals in research. When studies of monkeys are undertaken, they must– by US federal law– be justified and must ensure that only the smallest number of animals to accomplish the scientific aims are involved. One of the ways to minimize the number of animals used is to pool resources. In this post, we briefly describe a longstanding set of US research centers that are dedicated to nonhuman primate research, the National Primate Research Centers (NPRCs) funded by the US National Institutes of Health (NIH). The centers are important because they allow scientists working with NHPs to leverage the incomparable resources of NPRCs to enhance their research, while also conserving scarce resources and reducing the overall number of animals through sharing access to central animal colonies.
What are the US National Primate Research Centers?
The NPRCs consist of seven centers, located across the US (California, Oregon, Washington, Southwest, Tulane, Wisconsin and Yerkes). The NPRCs house roughly 20-30% of the NHPs in research in the US and each center maintains relatively large colonies. According to their website, “The NPRCs have more than 22,000 animals, including baboons, three species of macaques, marmosets and squirrel monkeys. The centers also have rodents, including mice, rats and voles.”
NPRCs in context: Comparison to overall number of NHP in research in the US
The number of NHPs in research in the US is roughly 70,000 and varies slightly across years. Under US law, facilities that use NHP in research must report the number annually and these reports, along with a national summary, are freely available via the US Department of Agriculture (USDA) website. Previous studies indicate that 27 facilities, including NPRCs, universities, and private companies, account for roughly 80% of NHPs in US research1,2. NPRCs account for roughly 20-30% of the US total. Many other academic institutions across the country also house NHPs for research conducted on site, but these are typically much smaller numbers of animals.
Finally, private industry accounts for roughly 40% of all US NHPs in research. In fact, in 2020 two large private contract research organizations accounted for 22,810 NHPs, or roughly the same number of NHPs as the seven primate centers combined. Charles River Laboratories (CRL) reported 15,769 nonhuman primates in research and Labcorp reported 7,041. For an international comparison, a 2014 report indicated that China’s research and breeding population of NHPs is roughly 290,0003. A 2015 analysis4 estimated that, compared to 61,950 NHPs in research in the US, China used 50,558, Japan 11,426, Brazil 5,413, Canada 4,942, UK 3,612, France 3,162, Germany 3,118, India 2,972, and South Korea 2,544. The analysis also showed a strong correlation between animals used in research and scientific productivity as measured by scientific publications. The population, economy, number of universities, and national investment in research also vary across these countries.
What is unique about the NPRCs?
The NPRC system was established in the 1960s with legislation passed by Congress creating centers funded by the NIH to fill a unique need to support a broad range of scientific studies and reduce the need for animals imported from other countries. Unlike private industry, the main mission of the NPRCs is to provide resources for scientists conducting basic and translational research with NHPs.
The centers provide an unparalleled combination of infrastructure, animals, equipment, expertise and collaborations (https://www.nprcresearch.org/primate/capabilities.php) to support research projects by scientists from all over the world. Pilot research grant applications are available each year to encourage investigators from other institutions to conduct their research projects at the NPRCs. In fact, approximately 1000 studies involving over 2150 investigators are conducted through the NPRCs each year (https://www.nprcresearch.org/primate/index.php). The NPRCs are supported by NIH and other government organizations, as well as private foundations and industry, which all recognize the incomparable value of the NPRCs for facilitating cutting-edge NHP research that benefits society.
The NPRCs breed and maintain a wide range of NHP species for research. Accessing these colonies avoids duplication of colonies elsewhere and contributes to reducing the overall number of NHPs used in research. Let’s take aging research as an example. Research in aging NHPs has long been impeded by the scarcity of suitable animals, due to the difficulty of maintaining NHP colonies over their entire lifespan. Recognizing the critical value of research in NHP models of aging, the National Institute on Aging (NIA) is maintaining approximately 300 macaques over the age of 18 years across several NPRCs, and similar efforts are ongoing to support aged marmoset colonies. NIA-funded scientists have the opportunity to make full use of these animal populations while avoiding duplication of colonies in their own laboratories.
As we have written elsewhere (for examples- here, here, here), NHP research is absolutely necessary for medical advances, from basic discoveries to translational applications. In face of scarce NHP availability, pooling NHP resources, whether at NPRCs or other institutions housing large NHP colonies, is vital to NHP research and scientific progress.
1Feister, A. J., DiPietrantonio, A., Yuenger, J., Ireland, K., & Rao, A. (2018). Nonhuman Primate Evaluation and Analysis. Part I: Analysis of Future Demand and Supply (Rep. No. 1). National Institute of Health. Retrieved from https://orip.nih.gov/sites/default/files/508%20NHP%20Evaluation%20and%20Analysis%20Final%20Report%20-%20Part%201.pdf
2Feister, A. J. (2018). Nonhuman Primate Evaluation and Analysis. Part II: Report of the Expert Panel Forum of Challenges in Assessing Nonhuman Primate Needs and Resources for Biomedical Research (Rep. No. 2). National Institute of Health. Retrieved from https://orip.nih.gov/sites/default/files/NHP%20Evaluation%20and%20Analysis%20Final%20%20Report%20-%20Part%202%20Final%20508%2021Dec2018_002.pdf
3Zhang, X. L., Pang, W., Hu, X. T., Li, J. L., Yao, Y. G., & Zheng, Y. T. (2014). Experimental primates and non-human primate (NHP) models of human diseases in China: Current status and progress. Dongwuxue Yanjiu, 35(6), 447-464. doi: 10.13918/j.issn.2095-8137.2014.6.447
4Taylor, K., & Alvarez, L. R. (2019). An estimate of the number of animals used for scientific purposes worldwide in 2015. Alternatives to Laboratory Animals, 47(5-6), 196-213.