Study: Redheads maybe risk melanoma even without sun

(If you are a mouse  -- apparently there ARE red-haired mice)

Doctors have long urged people with red hair, fair skin and freckles to avoid the sun and its damaging ultraviolet rays. To venture outdoors without a wide-brimmed hat and sunscreen was simply courting skin cancer, they cautioned.

Now, however, a study in mice suggests that those among us with ginger hair and fair complexions face an elevated risk of the disease even when covered up.

The study, published online Wednesday in the journal Nature, suggests that the same reddish-yellow pigment that gives rise to rusty locks and an inability to tan is itself a potential trigger in the development of melanoma, the deadliest form of skin cancer.

The findings appear to solve the riddle of why darker-skinned individuals have a significantly lower risk of melanoma than lighter-skinned people, even when the sun protection factor, or SPF, of dark skin is just two to four levels higher than that of light skin. It could also explain why red-haired individuals are more susceptible to melanoma than anyone else, even blonds.

"Even if you're good about avoiding UV rays — you know, putting on sunscreen, wearing protective clothes and being careful at the beach — it's still possible this red pigment is related to carcinogenic activity anyway," said Dr. David E. Fisher, director of the melanoma program at Massachusetts General Hospital in Charlestown and senior author of the study.

Melanoma is a from of cancer that begins in the skin's pigment-producing cells, or melanocytes, and is often associated with fair skin, excessive exposure to sunlight and tanning lamps, or a preponderance of moles. The National Cancer Institute estimates that more than 76,000 people will be diagnosed with melanoma in 2012 and that more than 9,000 will die from it.

The color of human skin, hair and eyes is dictated by two types of melanin pigment: pheomelanin, which is reddish-yellow, and eumelanin, which is brownish-black. Both are produced in the upper layers of the skin, and people with a greater proportion of brown-black pigment will have a darker complexion than people who have a greater percentage of the red-yellow pigment.

Initially, Fisher and colleagues set out to examine how moles can develop into melanoma when exposed to ultraviolet light, a form of radiation that can damage DNA. The test subjects were mice bred to be susceptible to cancer. Because mouse hair is also determined by eumelanin and pheomelanin, researchers used black, albino and golden-yellow — or "red-headed" — mice to mimic a range of human pigmentation.

Yet even before researchers got a chance to expose the mice to UV rays, 50% of the redheads developed melanoma within a year. Their black and albino counterparts, however, developed melanoma at low rates and over a longer period.

"We were very surprised," Fisher said. "In fact, one of the first things we did was go back into the animal room with a UV meter just to be sure that for some inexplicable reason the lights were not actually emitting ultraviolet radiation."

Study authors surmised that since UV radiation could not have caused the cancer, the pheomelanin pigment itself was causing a damaging chemical reaction inside the animals' skin cells.

SOURCE




Vigorous daily exercise could help to repair damage from heart failure

If you are a rat

Strenuous daily exercise could help to repair the heart of someone who has just suffered a heart attack, according to a new study.

Researchers at Liverpool John Moores University found that vigorous regular exercise led to dormant stem cells in the heart becoming active. This stimulated the development of new heart muscle.

The findings, published in the European Heart Journal, suggest that scientists could soon be able to improve the quality of life for people suffering from heart disease or heart failure.
British Heart Foundation

This is the first study of its kind to suggest that a basic exercise regime could have the same effect on the heart as injecting growth chemicals to stimulate stem cells to produce new tissue.

The team of scientists, funded by the British Heart Foundation, studied healthy male rats for up to four weeks by exercising them on an intensity-controlled treadmill for half an hour, four times a week.

The rats on a high-intensity programme showed the greatest increase in the size of their hearts, as expected, but also their aerobic capacity - how well the heart, lungs and blood vessels work.

The exercise resulted in more than 60 per cent of heart stem cells becoming active. In adults these stem cells are usually dormant.

After only two weeks the rats had increased the number of cardiomyocites, the 'beating' cells in heart tissue, by seven per cent.

Professor Jeremy Pearson, associate director of the British Heart Foundation, said: 'This study adds to the growing evidence that adult hearts may be able to make new muscle from dormant stem cells.

'However, much more research is now needed to find out whether what's been seen in this study can be translated into treatments for human patients.'

SOURCE