Primates represent only about 1/3 of 1 percent of animals used in research. But during the last half century, research using primates has led to major medical breathroughs, most notably in the treatment of polio and Rh disease. Vaccines have reducing the cases of polio in the U.S. from 58,000 to one or two a year at present, and the development of RH immunoglobin has reduced cases of RH disease in babies to fewer than 16 in every 10,000.
Scientists are learning how the Human Immunodeficiency Virus (HIV) works by studying its nonhuman primate counterpart, the Simian Immunodeficiency Virus (SIV) in monkeys.1 The SIV model is useful in testing drugs for AIDS. In addition, the HIV virus survives in certain kinds of monkeys and although it does not kill the animals, it can be recovered from them. This may prove useful in testing an AIDS vaccine.
Research on baboons has led to a cell-separation technique that allows cancerous cells in bone marrow to be removed without destroying healthy cells. Cell-sorting and transplantation techniques are now being testing in humans.2
- Chimpanzees are being used to develop a new approach to diagnosing cancers that arise from solid tumours.3
- The cotton-topped tamarin, a monkey native to Columbia, spontaneously develops inflammations in the colon. These are similar to those in humans that lead to colon cancer, the second most common form of cancer in the United States. Scientists are studying the relationship between the inflammatory disease and the cancer.4
Research on monkeys has led to development of dietary supplements to treat homocystinuria, a condition that can lead to atherosclerosis, which causes blockage of the arties and is the leading cause of death in the Western world.5
- Baboons are being used in the development of artificial blood vessels to bypass or replace segments of arteries block by atherosclerosis.6
Drugs are being studied in monkeys to cure malaria, a parasitic disease responsible for 2.3 million deaths annually.7
Researchers are using monkeys to develop a technique to treat Parkinson’s disease, which causes an increasing loss of muscle control and eventually leads to death.8
- Primate research has identified one of the important features of Alzheimer’s disease – an an abundance of clusters of nerve ending in the brain of Alzheimer’s victims.
- Primates are being used to examine ways of restoring muscle functions to human limbs paralyzed by spinal cored damage.9
Researchers are studying rhesus macaque monkeys to explore ways to reduce multiple organ failure following hypotensive shock, a loss of blood pressure due to loss of blood. Researchers have hypothesized that damage to the organs can occur within the first few minutes after blood flow is re-established, when a certain kind of white blood cell attaches to walls of blood vessels and releases toxic substances. The researchers reasoned that if, just before blood flow is re-established, a substance that prevent the white blood cells from attaching to the vessel walls were injected into the blood stream, it might prevent the release of their toxic contents and avoid multiple organ damage. It is expected that this new technique will prove effective in human patients.10
Researchers are studying obesity in monkeys in hopes of finding a way to control body weight.11 Scientists are also using monkeys to study Taurine deficiency, which causes vision problems, and zinc deficiency, which causes growth retardation among infants and foetuses.12
- Researchers are currently studying to see whether reduced caloric intake can slow the rate of aging. This effect has already been observed in lower animals, and if it holds true in primates, it would be a strong indication that humans might be able to increase their life spans by eating less.
Research on primates is providing clues to what causes infertility and what might be done to raise the success rate of in vitro fertilization.13
1 Fultz, PN; McClure, HM; Anderson, DC; Swenson, RB; Anand, R and Srinivasan, A: Isolation of a T-lymphptropic retrivirus from naturally infected sooty mangabey monkey (Cerocebus atys). Proceedings of the National Academy of Science, 83:5286-5290, 1986.
2 Berenson, RJ; Andrews, RG; Bensinger, WI; Kalamsz, D; Knitter, G; Buckner, CD; Bernstein, ID: Antigen CD34+ marrow cells engraft lethally irradiated baboons. Journal of Clinical Investigation 81:951-955, 1988.
3 Metzgar, RS; Borowitz, MH; Hollingsworth, MA; Kim, YW; Lan, MS: Monoclonal anytibody assays for pancreatic cancer. In: Cancer Diagnosis in Vitro Using Monoclonal Antibodies. Kupchik, H (ed) Marcel Dekker, Inc., 169-193, 1988.
4 Madara, JL: Structural characterization of spontaneous colitis in cotton-top tamarins (Sanguinus Oedipus). Digestive Diseases and Sciences 30:52S, 1985.
5 Malinow, MR.: Hyperhomocyst(e)inemia, a common and easily reversible risk factor for atherosclerosis. Circuation 81:2005-2006, 1990.
6 Clowes, AW: Arterial wall response to injury and Healing. Journal of Vascular Surgery 9:373-375, 1989.
7 Krotoski, WA; Garmham, PCC; Cogswell, FB; Collins, WE’ Bray, RS; Gwadz, RW; Killick-Kendrick, R; Wolf, RH; Sinden, R; Hollingdale, M; Lowrie, RC Jr.; Koontz, LC; Stanfill, PS: Observations on early and late post-sporozoite tissue stages in primate malaria IV, pre-erythrocytic schizonts and/or hypnozoites of chesson and North Korean strains of Plasmodium vivax in the chimpanzee. America Journal of Tropical Medicine and Hygiene35:263-274, 1986.
8 Bakey, RAE; Barrow, DL; Fiandaca, MS; et al: Biochemical and behavioural correction of MPTP Parkinson’s like syndrome by fetal cell transplantation. Annals of the New York Academy of Sciences 495:623-640, 1987.
9 Kennedy, PR: the cone electrode: A long-term electrode that records from neuritis. Society of Neuroscience Abstracts 14:1261, 1988.
10 Vatner, SF; Patrick, TA; Knight, DR; Manders, WT; Fallon, JT: Effects of a calcium channel blocker on response of blood flow, function, arrhythmias And extent of infarction following reperfusion in conscious baboons. Circulation research 62:105-115, 1988.
11 Kennitz, JW; Goy, RW; Flitsch, TJ; Lohmiller, JJ; Robinson, JA: Obesity in male and female rhesus: Fat distribution, glucoregulation and androgens. Journal of Clinical Endocrinology and Metabolism 69:287-293, 1989.
12 Golub, MS; Gershwin, ME; Hurley, LS; Cheung, ATW and Hendrickx, AG: Effects of marginal dietary zinc deprivation on the development of rhesus monkey infants. Federation Proceedings 44:932.
13 Wolf, DP; Vande Voort, CA; Meyer-Hass, GR; Zelinski-Wooten, MB; Hess, DL; Baughman, WL; Stouffer, RL: In vitro fertilization and embryo transfer in the rhesus monkey. Biology of Reproduction 41:335-346, 1989.
14 Oregon Regional Primate Research Center: “Toward Better Health”, Primate News Vol. 24 (Fall 1990).