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publicado em 13/02/2011 às 13h30:00
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Scientists identify major route of aging on the body

Research shows that telomere dysfunction and activation of p53 triggers a wave of cellular and tissue degeneration

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Studies in mice have led scientists at the Cancer Institute Dana-Farber in the United States, identifying the main pathway of aging in the body. The discovery relates various biological processes associated with age only previously seen as independent.

According to the researchers, the results are of great importance for human aging as this central pathway can be directly linked to virtually all known genes involved in aging, as well as to current therapies designed to reduce the damage of aging on health .

telomere dysfunction

The scientists found that the main cause of declining health in relation to age is not the correct functioning of telomeres - the caps at the end of chromosomes that protect against DNA damage.

As the cells reach their pre-determined limit of times you can divide, the telomeres become shortened and frayed, making it vulnerable to chromosomal terminations increased rates of unrepaired damage to DNA.

Faced with this growing reservoir of damaged DNA, cells activate the p53 gene, which sounds an alarm and shuts down normal cell growth and division cycle, ordering them to "rest" until the damage can be repaired or, if not , self-destructed.

Scientists had previously accused the emergency shutdown and cell death were to blame for age-related deterioration in organs whose cells divide rapidly and are rejuvenated by the reservation of adult stem cells. Such tissues include skin, intestinal cells and blood cells, among others, that generate trillions of new cells every day of life.

metabolic failed

However, scientists still do not know how cells with less cell division, such as heart or liver, maintain equivalent levels of aging.

The new findings show that telomere dysfunction and activation of p53 also trigger a wave of cellular and tissue degeneration.

According to the study, telomere dysfunction also triggers a series of reactions leading to reduction in health and longevity. For example, the muscles suffer a loss of mitochondria causing less vitality and failure of the heart and other organs. Risks of metabolic diseases such as diabetes are increased.

The scientists found that the telomere dysfunction causes this wave of failures because when the metabolic gene p53 is activated, it represses the functions of two regulators of metabolism - PGC1? alpha and PGC1? beta.

The repression of these regulators reduces the metabolic processes needed to provide energy and stress resistance.

In experiments with mice, scientists showed that removal of p53 regulators released the brakes PGC1? alpha and PGC1? beta.

"This is the first study that directly links the telomere dysfunction to the regulators of mitochondrial defense and anti-oxidant through p53," noted the study's senior author, Ronald A. DePinho. "By unifying several major pathways of aging under the protection of telomere dysfunction, the finding may yield new targets for therapies."

   Palavras-chave:   Aging    Telomeres    Cell degeneration    Cancer Institute Dana-Farber   
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