Genetics of aging: implications for drug discovery and development.

Aging is not a passive activity, but an actively regulated metabolic process. Specific genes have been identified that regulate aging, although aging, and consequently longevity, is only partially under genetic influence. It is also possible to increase life span by environmental modification; for example, caloric restriction can increase life span. Because human life span is long, directly studying aging in humans is impractical. Fortunately, significant insights into aging can be achieved by studying short-lived organisms, such as yeast, worms, and fruit flies. Many of the molecular pathways regulating aging in these lower organisms are conserved in mammals and overlap with pathways regulating metabolism. For example, an insulin-growth hormone signaling system has been implicated in regulating aging and longevity in both worms and mammals. Furthermore, the dysregulation of glucose homeostasis is a hallmark of aging in humans. In fact, type 2 diabetes, a disease of glucose homeostasis, can be conceptualized as a form of accelerated aging. Consistent with this, aging and diabetes are both common risk factors for a wide range of diseases. Because aging and diabetes are intimately related at a molecular level, diabetes may be able to provide the link between disease treatment (eg, diabetes) and the prevention of age-related diseases. If specific molecular pathways controlling the rate of aging can be modulated genetically, then perhaps they can be modulated pharmacologically. These insights may ultimately have an important impact on the discovery and development of drugs to both treat and prevent a wide range of diseases.