Sunday, November 22, 2009

Child abuse may shorten cell lifeline: study

Beaten or sexually abused children are more likely to show accelerated ageing of cells later in life, a condition linked to higher rates of cancer and heart disease, according to a study released Friday.

Investigators found that the natural process by which protective "caps" on the end of chromosomes, called telomeres, are worn away as humans age was accelerated among adults who had suffered such trauma in childhood.

Earlier studies had shown that psychological stress elevates risk for a wide range of diseases and mental conditions.

And separate research had shown that telomeres shorten at a higher rate when exposed to toxins such as radiation or cigarette smoke.

But whether childhood emotional trauma could affect the enzymes in adulthood remained unknown.

To find out, researchers Audrey Tyrka of Brown University in Providence, Rhode Island measured DNA extracted from blood samples of 31 18-to-64 year old adults, including 22 women and nine men.

They found more rapid shortening of telomeres only in those who said they had suffered severe mistreatment as children.

The findings were not affected by the effects of age, smoking, body fat or other demographic factors, the paper said. "Both physical neglect and emotional neglected were significantly liked to telomere length," it concluded.

"This gives us a hint that early developmental experiences may have profound effects on biology that can influence cellular mechanisms at a very basic level," Tyrka said.

More research is needed to confirm the link, and to understand the causal pathways, she said in a press release.

Telomeres and telomerase, the enzyme that control them, are a key ingredient in ageing and longevity.

Every time a cell divides, the telomeres get worn down. The enzyme's job is to partially rebuild them. Eventually, when the telomeres are worn beyond a certain point, cell death is triggered.

Australian-American cell biologist Elizabeth Blackburn, who shared the Nobel Prize in Medicine last month for breakthrough research on telomeres, likened them to "tips of shoelaces" -- when you lose the little plastic end, the lace starts to fray.

The new findings are published online in the US-based journal Biological Psychiatry. (AFP)

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