Causes of Senescence in Elderly:
Cellular senescence is one phenomenon by which normal cells cease to divide. In their seminal experiments from the early 1960s, Leonard Hayflick and Paul Moorhead found out that normal human fetal fibroblasts in culture reach a maximum of approximately 50 cell population doublings before becoming senescent. Senescence is the process by which cells irreversibly stop dividing and enter a state of permanent growth arrest without undergoing cell death. Senescence can be induced by unrepaired DNA damage or other cellular stresses.
The most common cause is DNA double strand breaks, which bring about the DDR and consequently make cells senescent. Other examples that also act through the DDR include the presence of mitogenic signals, reactive oxygen species or certain proteins that promote cell growth and proliferation. As cells replicate, telomeres shorten at the end of chromosomes, and this process correlates to senescence or cellular aging. Integral to this process is telomerase, which is an enzyme that repairs telomeres and is present in various cells in the human body, especially during human growth and development.
Senescence belongs to the antagonistic class, while proteostasis dysfunction and disruptions in the signaling pathways are the integrative drivers. Senescence is the process of stable, irreversible growth arrest of cells. This process contributes to aging and age-related diseases. “Premature” senescence is an active cytostatic program that is triggered in response to proliferative or genotoxic stress, such as the expression of strong oncogenes, tumor suppressor loss, exposure to DNA damage, and reactivation of tumor suppressor pathways. Unlike replicative senescence, premature senescence can be induced irrespective of the replicative “age” of cells, is independent of telomere attrition, and cannot be overridden by restoration of telomerase activity. The Journal of Aging and Geriatric Medicine is publishing the articles related to Senescence.
Veronika| Managing Editor
Journal of Aging and Geriatric Medicine
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