Tuesday, January 31, 2012

Stress causes hair to turn gray, and the body-age

Graying of the hair, the most obvious sign of aging, may be a response to DNA damage as a result of stress. Something that can stop the stress, may prevent premature hair graying.

Studies Emi Nishimura of Tokyo Medical and Dental University (Tokyo Medical and Dental University) showed that "genotoxic stress", which damages the DNA, reducing the number of melanocyte stem cells (MSCs) in the hair follicles, which are responsible for creating the pigment-producing cells. Instead of dying, these precious stem cells differentiate, forming fully mature directly melanocytes.

It is believed that every cell in mammals can encounter in by day with approximately 100,000 events that destroy the DNA.

Consequently, cells have ways to repair damaged DNA and prevent the destruction were transferred to daughter cells.

Once the stem cells are damaged irreversibly damaged by the stem cells must be eliminated to maintain the quality of the stem cell pool. The researchers found that excessive toxicity genes increase the differentiation of stem cells triggers melanocyte. Perhaps the differentiation might be a more complicated way to get rid of these cells than stimulating their death.

Nishimura group earlier traced the loss of hair color to the gradual extinction of stem cells that maintain a continuous supply of new melanocytes, giving their hair a normal color. Those specialized stem cells not only lost, they have also become completely transferred to the pigment cells and in other places.

It is also found that the "temporary gene" known as ATM (ataxia-telangiectasia, mutated), is the so-called stem checkpoint, which prevents the differentiation of stem cells. That's why people with ataxia telangiectasia (Louis-Bar syndrome), caused by a mutation in the gene ATM, go gray prematurely.

The discovery shows that the instability of the genome - a significant factor in aging. Long-lasting damage to DNA of stem cells could be the main cause of age-related symptoms.

In addition to associated with aging, stem cell depletion, typical to that seen in melanocyte stem cells, changes were observed in blood stem cells, cardiac muscle, and skeletal muscle. Stress on stem pools were also responsible for reducing the ability of tissue regeneration and accelerated signs of aging.

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