About Aging Pathway Atlas Searching DB Data Input Gene Ontology

 
Aging
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 Aging is multi-factorial process which occurs at celluar, organ and intact organism levels. Biological aging process is time-dependent and deteriorative changes that occur in all living cells. These chages are accociated with an increased incidence of cardiovascular and cerebrovascular diseases, diabetes, hypertension, age-associated disease and so on. Recent advances in biomedical gernotology indicate that aging processes are influenced by both intrinsic and extrinsic factors.
 Genetic makeup, lifestyle and environmental factors influence the rate of aging in an individual. The genetic makeup of individuals is predetermined, and presently little can be done to influence the aging rate of an individual by genetic manipluations. On the other hand, lifestyle and enviromental factors can interact with aging process and my alter susceptibility of individuals to age-associated diseases. Accumulating evidences suggest that may aging processes can be modified through interventions and modulating extrinsic factors to improve the quality of life. Of the extrinsic fatctors, nutriotion, exercise, and antioxidants appear to be the strongest factor known to influence the rate of aging and incidence of age-associated diseases. 

 
Aging theories
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 Many theories of aging proposed over them years have been aimed at identifying the nature of the primary aging process or processes. In fact, there have been many attempts to classify theories of aging, however, until now, no single theory has accounted for phenotypes.
 Systemic theories ascribe aging of the entire organism to decrements the function of a key system, such as a nervous, endocrine, or immune system. Such decrements could be genetically programmed, as are the early developmental phases of the lifespan, or be the consequence of environmental insults, Alternation in the key system will generate changes throughout the entire organism.
 Molecular theories propose that the lifespan of any species is governed by the genes interacting with environmental factors. Genetic information is stores in the genes(nucleotides segment of DNA), is transcribed to RNA, and is subsequently translated into proteins. These proteins, either structural or functional, govern the form and function of organisms. Aging may result from changes in DNA template activity, which regulated the formation of the final cellular products. It is believed that gene expressions are carefully regulated and that the proteins produced by gene activity are involved in multiple interacting processes. A number of theories propose that changes in cellular proteins and other macromolecules occur as a function of age. These changes occur with the passage of time under the influence of environmental factors(e.g., nutrition and stress). They may be chemical and / or morphologic and involve enzymes, hormones, age pigments, free radicals, membrane permeability, macromolecule crosslinking, and changes in various cell organelles such as lysosomes and mitochondria.
 Especially, The free radical theory of aging claims that aging occurs as a consequence of the deterious effects oxygen free radicals produced during the course of metabolism. According to this hypothesis, free radical injury causes diminished enzyme activity, error-prone nucleic acid metabolism, impaired membrane function, and the accumulation of aging pigments. All these eventually lead to a decline in celluar integrity. A related concept cites that the intracellular redox state becomes progressively more pro-oxidizing with age and that an aging organism is more susceptible to oxidative stress. Since ordinary aerobic metabolism appears to be a major source of free radicals, it is estimated that 2% of the oxygen utilized by cells is only partially reduced and leaks as superoxide ??animals with higher metabolic rates would be predicted to have shorter life spans. Exogenous sources of free radicals, such as ionzing radiation, reduce life span and cause accelerated changes similar to the aging process. Also, a positive correlation has been found between tissue concentrations of the antioxidants, superoxide dismutase, carotenoids, alpha ??tocophreol, and uric acid, and life span in mammals. Individuals who consume low levels of antioxidants in food have higher incidences of degenerative diseases of aging compared to those with high intakes of food antioxidants.
 Furthermore, dietary manipulations in animals produce results that are consistent with the free radical hypothesis of aging. Caloric restriction has been shown to increase life span by over 40% and is associated with more tightly coupled mitochondrial respiration and a delay in age-related declines in antioxidant defenses.

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Citation Information
 
 When citing this database in any scientific publication please refer to it as:

  AgingDB : A database for oxidative stress and calorie restriction in the study of aging, Daeui Park et al, J. Amer. Aging Assoc., Vol. 26, 11-18, 2003  [paper download]