Ageing, telomere, stem cells biology and inflammation and their relationship to polyunsaturated fatty acids
Ageing is inevitable for all living organisms and the purpose of the present review is to discuss recent evidences that suggest that ageing could be delayed if not prevented in toto. Ageing is a low-grade systemic inflammatory condition so also type 2 diabetes mellitus, hypertension and endothelial dysfunction whose incidence increases with advancing age. Calorie restriction, exercise and parabiosis performed between old-young pairs are known to delay and to a limited extent reverse age-related changes in the body that have been related to enhanced proliferation of stem cells, decrease in inflammation and transfer of GDF-11 (growth differentiation factor-11) from the young to the old. Inhibiting ageing-related hypothalamic or brain IKK-β and NF-kB activation decreased gonadotropin-releasing hormone (GnRH) release enhanced ageing-impaired neurogenesis and decelerated ageing. This suggests that hypothalamus has a programmatic role in ageing development via immune–neuroendocrine integration. N-acylethanolamines (NAEs), lipid-derived signalling molecules, are reduced under dietary restriction and NAE deficiency extended lifespan in an mTOR dependent pathway manner. These results imply that a co-ordinated effort to inhibit inflammation, enhancing stem cell proliferation and restoring lipid-derived signalling molecules may prevent, delay or reverse some of the features of ageing.
It is estimated that approximately 100,000 people worldwide die every day of age-related causes. In biology, senescence is the state or process of aging. Cellular senescence is a phenomenon where isolated cells demonstrate a limited ability to divide in culture, while organismal senescence is the ageing of organisms. After a period of near perfect renewal (in humans, between 20 and 35 years of age), organismal senescence is characterized by the declining ability to respond to stress, increasing homeostatic imbalance and increased risk of disease. This irreversible series of changes inevitably results in death. As genes and environmental factors that influence aging are being discovered, ageing is increasingly being regarded as a disease that is potentially treatable like other diseases.
TELOMERE AND AGING
Indeed, aging is not an unavoidable characteristic of life. Instead, it is the result of a genetic program. In humans and other animals, cellular senescence has been attributed to the shortening of telomeres with each cell cycle; when telomeres become too short, cells die (1-3). The length ...