Science of getting old
L-R: Aging actually is the result of lifelong accumulation of various forms of damages at molecular and cellular levels. Productive pursuits, exercise, diet, genes and social activity together may help in healthy aging
Today, in this twenty-first century, life expectancy has become higher in the world, especially in the west. Indeed, in the previous century, people lived in constant association with death. It was very unlikely for twenty-five percent of the newborn to see their first birthday and again another quarter of the children died before their fifth birthday due to infection. But, the improved sanitation, living conditions and medical care over the past one hundred years have reduced death rates and life expectancy has been increased to the old age. The principal reason of death, today, is the aging process itself with the varieties of illnesses it gives rise to such as cancer, diabetes, heart diseases, Alzheimer's and Parkinson's diseases. The cells and multicellular organisms face numerous challenges to survive. In the process, cells get damaged all the time and thereby a repairing system is also on to heal the damaged conditions. However, this repairing system, although very efficient, may also leave few damaged conditions, those are called misrepaired conditions. The damage may occur in many forms such as DNA get altered, proteins get damaged and the free oxygen radicals released as the mitochondria degenerate and breakdown. The somatic cells, the cells other than the germ line cells (cells that give rise to sperm and eggs) of the body, function in maintenance and repair and are not immortal like germ line cells. Indeed, some organisms like freshwater hydra and jellyfish found not to age. Aging actually is the result of lifelong accumulation of various forms of damages at molecular and cellular levels. Certain genes are found to be involved in aging process. In 1980, Tom Johnson and Michael Klass have found a gene named age-1 in a nematode that increased the lifespan of the organism up to forty percent. On November 27, 2008, Science Daily reported that Harvard scientists Philipp Oberdoerffer and David Sinclair found sirtuin genes to play role in anti-aging. These genes repair damaged DNA and regulates gene expression by preventing the integrity of chromatin but they perform only one of these two tasks at once. Scientists now think this may be the actual cause of aging. Dietary restriction, in other studies, has been found to increase lifespan in mice but it is less likely to work in humans because the metabolism varies greatly between these two organisms. All individuals actually age and die, but the process varies. Cells respond to damages, sometimes by killing itself, the process of this self induced death of cells is called apoptosis. In aged cells, the frequency of apoptosis becomes higher and whereas the apoptosis is good at young age, it becomes the opposite at the old age when too many killing of cells by apoptosis accelerates the aging process. Recently, Thomas Kirkwood, professor of medicine and director of the Institute for Aging and Health at Newcastle University of England have made an exciting discovery. They found that after the amount of damage passes a threshold, the cell comes to a state of senescence where they can still perform useful functions in the body but lack the capability to divide. "But if we are to unpick the locks and so restore some division capacity to aged cells, we need to understand very thoroughly just how cell senescence works"- Thomas Kirkwood states. So, by restoring the division capacity of the cells locked at senescence and by preventing unnecessary apoptosis without the risk of causing cancer, may well increase lifespan and delay aging. Although some anti aging drugs are in development and a drug named resveratrol has been found to increase lifespan in mouse, the solution to the aging of human may not be that easy. Indeed, healthy or successful aging could be a good target for human. Productive pursuits, exercise, diet, genes and social activity together may help in healthy aging. "I believe we can and will develop treatments targeted at easing our final years" says Professor Thomas Kirkwood.
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