Hope for test to measure aging

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Scientists are developing a simple blood test to measure how fast the

body's tissues are aging at a molecular level.

They have found that as tissue ages, concentrations of a protein called

p16INK4a dramatically increases.

Measuring levels of the protein could potentially provide a way to

assess how healthy the tissues are, and how they will respond to surgery

or drugs.

The University of North Carolina study appears in the journal Aging

Cell.

" This is a major step toward a practical tool to clinically

determine a person's actual molecular, as opposed to just their

chronological age "

Dr Norman Sharpless University of North Carolina

Scientists are already interested in p16INK4a because it is known to

play a role in suppressing the development of cancer.

The protein is present in the T-cells of the immune system, which play a

key role in fighting disease, and repairing tissue damage.

Physical inactivity link

Not only did the North Carolina team show that levels were closely

related to cellular aging, they also found a strong link with certain

behaviours, such as tobacco use and physical inactivity, which are known

to accelerate the aging process.

They say they have overcome technical hurdles to begin perfecting a

simple blood test to detect levels of the protein.

To test its accuracy, they analysed blood samples from 170 people, who

also filled out a questionnaire about their health and lifestyle.

Researcher Dr Norman Sharpless said: " This is a major step toward a

practical tool to clinically determine a person's actual molecular, as

opposed to just their chronological age.

" Although we don't know whether this test is a good reflection of

cellular age in all types of human tissues, we believe it is a first

step toward a better understanding of issues like the suitability of

organs for transplantation, how well patients are likely to recover

after surgery or the future toxicity of chemotherapy for cancer

patients. "

The researchers were surprised to find that levels of the protein were

not linked to obesity, even though research has suggested that limiting

calorie intake may help to slow down the aging process.

Dr Sharpless said this raised the possibility that a lack of exercise

may have a more profound impact on molecular aging than being overweight

or obese.

Professor Tim Spector, of Kings College London, has carried out much

research into how aging is related to the length of strands of DNA

called telomeres which protect our chromosomes from damage.

He said: " p16INK4a clearly has potential for use as a novel marker of

biological aging.

" However, much more work in larger numbers needs to be done to see if it

is better than the other existing marker - telomere length - or indeed

if it is good enough to be useful at an individual level in predicting

rates of aging. "

Story from BBC NEWS:

http://news.bbc.co.uk/go/pr/fr/-/2/hi/health/8102811.stm