Nonhuman primate models in biogerontology.

A variety of animal models are utilized in biogerontological studies including yeast, nematodes, fruit flies, hamsters, mice, rats, and nonhuman primates. Species selection for research is based on many factors including economic feasibility, husbandry, generalizability of findings, available background information, adaptability to experimentation, and often, relevance to human aging. Each model offers its own strengths and limitations; however, nonhuman primates offer the unique advantage of phylogenetic proximity to humans. Among others, costs to purchase and maintain research subjects represent major limitations of nonhuman primate models. Although several nonhuman primate species have been utilized in aging research, rhesus monkeys (Macaca mulatta) are the best characterized and most extensively studied in biomedical gerontology. Nonhuman primate models have been employed as models for human aging in many research areas including neurobiology, skeletal, and reproductive aging and age-related diseases such as cardiovascular disease and diabetes. Primate models are now also being utilized to study interventions into aging such as caloric restriction. It will be several more years until definitive conclusions regarding lifespan effects can be made. However, existing data strongly suggest that many of the beneficial effects reported in rodents on CR also occur in primate models thereby strengthening the possibility that this nutritional paradigm may also impact favorably upon human aging.