Senescence describes the degenerative process that accompanies natural aging. It is not a synonym for aging itself, but merely encompasses its degenerative aspects.
What is senescence?
Senescence describes the degenerative process that accompanies natural aging. Every living thing ages. The aging process is accompanied by senescence of its cells: that is, they do not divide as much as they did at the beginning of their life cycle. A young person still experiences rapid wound healing, growth and maturation of various organs, due in part to strong cell division activity. In old age, on the other hand, humans reach a point where wound healing is slowed and even degenerative diseases occur, usually due to reduced cell growth and thus structural weaknesses. This degenerative process is senescence. However, we speak of senescence in humans only when natural (cell) aging causes degenerative developments to take effect to the extent that the person suffers or becomes ill. Typical consequences of senescence are, for example, osteoporosis, the accumulation of the pigment lipofuscin (“age spots“) or the higher mortality rate in old age due to such degenerative processes in the body. Usually, the processes of senescence begin just after the end of the reproductive phase, as important hormones then cease to exist. It is not always possible to clearly distinguish between aging and senescence.
Function and task
Each living being has a different lifespan, which is dependent on the lifestyle and influences during its lifetime, as well as possible life-threatening diseases. In humans, this lifespan was about 30 years in earlier centuries and millennia because of this – now there are many people who live to be over 100 years old. Senescence affects the individual life span. It is therefore less to be regarded as a useful development for the individual, but rather contributes in an evolutionary sense to the fact that living beings die. If humans were immortal, they could pass on their genes, thus possibly producing more viable offspring, but soon there would no longer be enough living space for all offspring and parent generations on earth. Aging itself does not necessarily lead to death. Senescence as a component of the aging process, on the other hand, brings about the degenerative processes that can end in age-related death. Together with diseases that occur either due to the physical weakening of senescence or for other reasons in old age, senescence is one of the most frequent causes of death of old and aging people in the long run. It cannot be stopped, however, with the methods of modern medicine, it is possible to positively influence degenerations caused by senescence and thus provide aging people with a better quality of life. Life-sustaining and palliative measures can alleviate symptoms of degenerative processes at the end of life and ensure freedom from pain. A separate branch of medicine, geriatrics, deals with the treatment of the consequences of senescence. It is exclusively responsible for senescence-related diseases in old patients and therefore also assumes an important role in the psychological care of the aging patient. Senescence offers a potentially positive perspective in cancer research. Cancer cells divide rapidly, faster than healthy cells. If it were possible to decelerate cell division, as in senescence, it would be possible to
tumors that have already developed could be reprogrammed so that they do not divide. In a sense, the cancer could be “frozen” with the help of senescence.
Diseases and ailments
Since senescence is a degenerative and not completely stoppable but natural process in the cycle of life, it must not be considered a curable phenomenon. Senescence itself is not a disease. Only its manifestations can acquire disease value or even be fatal, while others do not result in any medically relevant complaints. The more harmless manifestations of senescence include skin aging. Certain connective tissue cells stop dividing after a certain number of cell divisions, the connective tissue of the skin becomes weaker, can store less moisture – wrinkles develop.In old people, blotchy discolorations of the skin are also frequently seen: they result from the fact that the pigment lipofuscin can no longer be broken down and consequently visibly accumulates in the skin. From an aesthetic point of view, this may all be unpleasant and distressing, but it is still medically relevant. More complicated are the reduction of immune activity, which ends in more frequent and worse infections, the reduction or even loss of vision, or the slackening of muscles, which weakens the person as a whole, since internal muscles such as the heart muscle can also be affected. Such consequences of senescence can end in serious illnesses and ultimately lead to the death of the aging person. Such processes could only be stopped or cured if the responsible cells could be induced to divide again. However, since this is not possible, palliative and life-sustaining medicine plays a major role in geriatrics. Pain treatments and drugs that at least delay the consequences of senescence and thus preserve life longer are the most important guarantors of the highest possible quality of life despite senescence.
