The role of heredity factors
in ageing have long been realized through the discovery of longevity genes and through the study of the early onset of old-age diseases
. Ageing occurs at various levels
- at the DNA, cells or tissues. If the cells are not repaired after a DNA damage, cells age or undergo self-destruction (apoptosis). Apoptosis,
or programmed cell death, plays a vital role in controlling diseases like cancer. Nevertheless, it play a crucial role in organ deterioration and failure. Ageing is also attributed to the progressive impairment of the genes involved in the maintenance and repair of cells and tissues. Cell senescence
(or replicative senescence) is another phenomenon that is often referred to as the pathway of ageing. After about 50 cycles of division, cells reach a ‘cul de sac’
and lose their ability to divide any further. Environment
too plays an important role in accelerating the ageing process. Even if oxygen, which is a requisite for life, exceeds above 50%, the cells become cytotoxic.
Our present day lifestyle choices
add to all the existing causes and aggravate morbidity during old age.