Primates in Biomedical Research: The Need to Use Primates in Research

Introduction

From: 1999 Report of Progress, p.39-41 (Southwest Foundation for Biomedical Research)

THE NEED TO USE PRIMATES IN RESEARCH

"...Alternative methods to the use of animals as disease models are employed whenever possible. However, animal experimentation continues to be absolutely essential for... improving human health through basic and applied biomedical research..."

BACKGROUND ON ANIMAL RESEARCH

During the 20th century, virtually every major advance in medical knowledge and treatment involved research using animal models. Two-thirds of Nobel Prizes in Medicine awarded since 1901 were won for discoveries that required the use of animals.

Research involving animals is vital to continued medical progress in both human medicine and veterinary medicine. Animal research has saved lives, extended life expectancy, and improved the quality of human life by enabling scientists to conduct critical experiments that identified ways to prevent, treat, and cure diseases.

There has been a steady decline in the numbers of animals used in medical research as documented by the USDA, and medical research with human subjects is more common than animal-based biomedical research.

About 1.35 million animals were used in medical research in 1996 according to the USDA. Approximately 90 percent of the animals used in research are rats, mice, and other rodents specifically bred for research. One percent are cats and dogs, and less than 0.5 percent are primates. Many other types of animals also are used in research, including pigs, sheep, cows, rabbits, and fish.

While the percentage of research efforts involving nonhuman primates is small, nonhuman primate research has led to major medical breakthroughs in the treatment and prevention of diseases such as polio, Rh disease, and hepatitis.

REGIONAL PRIMATE RESEARCH CENTERS: A NATIONAL SCIENTIFIC RESOURCE

The NIH Regional Primate Research Centers (RPRCs) are a unique network of nonhuman primate research laboratories established as a scientific resource of regional and national importance to the advancement of biomedical and behavioral research.

They provide for the development and study of nonhuman primate models that are essential for basic and clinical research on human health and disease-related processes. Research at the primate centers also focuses on characterizing diseases that naturally occur in nonhuman primates, some of which pose threats to human health.

The RPRCs centralize facilities and scientific expertise in primate research, providing a cost-effective mechanism to address national needs for medical and behavioral research relying on a broad range of nonhuman primate species.

There currently are eight Regional Primate Research Centers distributed around the country. Seven were established in the early 1960s in Washington, Oregon, Georgia, Massachusetts, Wisconsin, Louisiana, and California. The eighth Regional Primate Research Center, the Southwest Regional Primate Research Center, was established on June 1, 1999, at the Southwest Foundation.

Information about the Regional Primate Research Centers program can be found at http://www.ncrr.nih.gov/compmed/cmrprc.htm

ADVANTAGES OF NONHUMAN PRIMATE MODELS IN RESEARCH

Genetic and Physiological Similarities
Primates are genetically and physiologically more similar to humans than are other animal species. Use of nonhuman primate models allows investigation of complex physiological characteristics that are shared only by humans and other primates.

Infectious Disease Susceptibility Similarities
Only humans and other primates are susceptible to many of the infectious diseases that threaten human populations.

Similarities in Characteristics of the Menopause
Only humans and some nonhuman primates undergo menopause. No other animal models are available for studying health issues related to the natural onset of menopause.

Similarities in Chronic Disease Profiles
Primates more closely resemble humans than any other animal model in manifestations of the chronic diseases that are the major public health problems in the United States today. For example, nonhuman primates have naturally occurring atherosclerosis, osteoporosis and hypertension making them ideal animal models for these conditions.

Ability to Control Matings
The ability to control breeding of nonhuman primates allows experimental testing of specific genetic hypotheses that is not possible in human populations

Ability to Control Environment
Primates can be maintained in a similar environment throughout life. The ability to control and maintain environmental factors facilitates many experimental evaluations not possible in human populations.

ALTERNATIVES TO ANIMAL RESEARCH

Many research questions only can be answered through detailed study of a whole living system. Disease processes are often complex, involving multiple physiological processes and multiple organ systems.

While some specific research questions may be adequately addressed using cell cultures, tissue studies, or computer models, whole animal research continues to be critical for the advancement of human health.

Adjuncts to animal research, frequently termed "alternatives," can complement research using whole animals but cannot replace the need for whole animals in biomedical research on complex normal and disease-related processes.

JUDICIOUS USE OF PRIMATES IN RESEARCH

The vast majority of animal research is done with mice and rats. Primates are used as research subjects only when a scientific question cannot be answered by using lower animals.

When primates must be used, the lower primates (monkeys) are used whenever possible. Chimpanzees are used only when the scientific question requires the use of a higher primate species (apes).

USE OF ANESTHESIA IN ANIMAL RESEARCH

According to the USDA, 93 percent of research animals do not experience pain related to experimental use either because the experiments have no painful procedures associated with them (58 percent) or because anesthesia and or painkillers are used in the experimental protocol (35 percent).

Some carefully regulated and monitored research studies (7 percent) where anesthesia or painkillers are not given are necessary for studies of chronic pain, or are necessitated when anesthesia would compromise the scientific quality of the data.