New research has provided the first evidence that along with pollution, smoking, obesity, and diesel exhaust, oxidative stress acts directly on telomeres to speed up cellular aging. The research has shown how stress can cause our biochemical body clock built into our chromosomes to tick faster.
DNA which is the genetic material found in our cells, doesn’t freely float in cell nuclei, but is organized into clumps of chromosomes. When a cell divides and produces a replica of itself, it has to make a DNA copy of itself. During this process a tiny portion is always lost at one end of the DNA molecule.
To protect some of the vital portions of DNA from being lost in this process, the ends of the chromosomes are capped with telomeres. These telomeres are gradually shortened during cell division. Gradual shortening of the telomeres acts like a cellular clock. Each replication causes them to get shorter and they eventually reach a point when they become too short sending the cell into a programmed death process.
Cellular aging is just one of the components related to aging. But it is one of the most important. The gradual deterioration of tissues in our body and the irreversible death of cells are responsible for some of the most visible effects of aging. This includes wrinkles, physical fitness and neurodegenerative diseases.
So far answers to what are some of the factors that may slow down or speed up the loss of our telomere clock have so far been inconclusive. Some studies have shown glimpses of potential mechanisms which suggest things like infections and even dedicating extra energy to reproduction may could possibly accelerate shortening of the telomeres and thus speed up cellular aging.
Although the evidence so far is piecemeal, these factors all seem to have one thing in common. They all cause physiological stress. Our cells become stressed when their biochemical processes are disrupted either by a lack of resources or for some other reason. If cells lose too much water they become subject to dehydration stress.
Other types of stress also count. Overwork and tiredness can put us under chronic stress. Anxiety for prolonged periods, emotional stress, and lack of sleep can also alter internal cellular pathways which includes telomere functioning. The question then becomes, can a variety of stress factors experienced by a person actually accelerate their rate of aging?
Many studies have looked at this question in specific species such as rats, mice, and various bird and fish species, both in the wild and in the lab. Findings from these studies suggest that telomere loss is profoundly affected by stress. The type of stress is important with the strongest negative effects caused by competition for resources, pathogen infections, and investment of energy into reproduction. Other kinds of stress such as a poor diet and human disturbance or urban living, also hastened cellular aging although to a lesser extent.
Oxidative stress was identified as a possible factor as to why stress can exert such a powerful influence on our cellular clocks. When cells are exposed to stress, it often manifests itself through an accumulation of oxidizing molecules such as free radicals. Free radicals are chemically reactive molecules that can attack the protective telomere end caps. These end caps which are exposed ends of our chromosomes are perfect targets for these chemically reactive molecules.
Analysis does suggest that no matter the type of stress experienced, this oxidative stress just might be the actual biochemical process that links stress to telomere loss.
Additional research is needed to determine if the results mean that we should consume more antioxidants to help combat oxidative stress and therefore guard our telomeres. The researchers note that this is not the secret to stop the aging process. It is too fundamental to biology to simply get rid of completely. It does however highlight that reducing stress can have great beneficial benefits on our bodies. By ensuring we are drinking enough water, getting enough sleep, maintaining a healthy balanced diet, and engaging in physical activity, it will help keep our cells functioning nicely.
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