Exposure to Pollutants Speed Up Aging Process

Exposure to UV rays, ozone, pollutants lead to free-radical production in our bodies, which damages our DNA and tissues. A new study in the journal Nature by the West Virginia University's Kelley, suggests that unrepaired DNA damage can increase the speed of aging. Kelley and his team created genetically-modified mice with a crucial DNA-repair protein missing from their hematopoietic stem cells, immature immune cells that develop into white blood cells.

"By the time the genetically-modified mouse is 5 months old, it's like a 2-year-old mouse," said Kelley, associate professor and associate chair of research in the School of Medicine's Department of Physiology and Pharmacology.

"It has all the symptoms and physical characteristics. It has hearing loss, osteoporosis, renal dysfunction, visual impairment, hypertension, as well as other age-related issues. It's prematurely aged just because it has lost its ability to repair its DNA."

A normal 2-year-old mouse is about equivalent in age to a human in their late 70s to early 80s. Kelley and his colleagues found that markers for cell aging and cell damage were greater in the immune cells of genetically-modified mice compared to normal, wild-type mice.

Damaged cells are seen in liver and kidney too. These results suggest that unrepaired DNA damage may cause the entire body to age prematurely.

Free radicals will quickly interact with another molecule in order to gain electrons. When these free radicals interact with important biomolecules, such as a protein or DNA, it causes damage that can keep that biomolecule from working properly.

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Smoking, drinking and exposure to pesticides and other chemicals through occupational hazards all significantly increase free radicals.

"A cigarette has over 10 to the 16th free radicals per puff, just from combusted carbon materials," Kelley said.

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Human body is also constantly producing free radicals during a process used to turn food into energy, called oxidative phosphorylation.

"We have mechanisms in the mitochondria that mop free radicals up for us, but if they become overwhelmed--if we have over-nutrition, if we eat too much junk, if we smoke--the defense mechanism absolutely cannot keep up," Kelley said.

The amount of damage caused by free-radical formation becomes greater than the antioxidant defenses as aging progresses. Gradually, the balance between the two tips over to the oxidant side, and damage starts to win out over repair. If we are exposed to a greater amount of pollutants and accumulate more free radicals, this balance will be disrupted even sooner, causing premature aging.

West Virginia has the greatest percentage of obese citizens in the nation and a high rate of smokers and workers in high-pollution-exposure occupations along with comorbidities like diabetes, enhanced cardiovascular disease, stroke and renal issues.

"I come from an Appalachian background," Kelley said. "And, you know, I'd go to funerals that were in some old house--an in-the-living-room-with-a-casket kind of deal--and I'd look at people in there, and they'd be 39 or 42 and look like they were 80 because of their occupation and their nutrition."

Kelley believes it is best to prevent premature aging through lifestyle change. He says that focusing on slowing the aging process through preventive measures can improve the outcome for each comorbidity and add more healthy years to people's lives.

"The impact is less on lifespan and more on healthspan," he said. "If you could get people better access to healthcare, better education, easier ways for them to participate in healthier eating and a healthier lifestyle, then you could improve the overall economic burden on the population of West Virginia and have a much better outcome all the way around."



Source-Medindia