Chronic arsenic exposure can impair ability of muscle to heal after injury

November 10, 2015, University of Pittsburgh Schools of the Health Sciences

Chronic exposure to arsenic can lead to stem cell dysfunction that impairs muscle healing and regeneration, according to an animal study conducted by researchers at the University of Pittsburgh's School of Medicine and Graduate School of Public Health. In a report published online in Stem Cells, they noted that inhibiting a certain protein in an inflammatory pathway can reverse the harmful effects and that environmental exposures might explain why some people don't recover easily after injury or surgery.

More than 140 million people worldwide and 4 million Americans chronically ingest arsenic in their drinking water, said senior investigator Fabrisia Ambrosio, Ph.D., M.P.T., assistant professor of physical medicine and rehabilitation at Pitt and the McGowan Institute for Regenerative Medicine. The 21st most abundant metal in the Earth's crust, arsenic is naturally present in soil and bedrock-walled wells and has no odor, color or taste.

"Whereas previous research has examined the impact of arsenic and other environmental contaminants on stem cell function critical for fetal and child development, there is very little information about how such exposures may affect stem cells and their function in adulthood," Dr. Ambrosio said. "We wanted to see if environmentally relevant levels of arsenic impair the ability of to properly repair after injury, and we found out that it does."

In the study, mice drank water for five weeks, or about two human years, with the equivalent of 10 times the arsenic level considered safe for humans by federal standards. Similar levels are seen in about 8 to 10 percent of wells, said co-investigator Aaron Barchowsky, Ph.D., professor of environmental and occupational health at Pitt Public Health. Then the researchers injured muscle in the exposed mice and compared the outcome to those of mice that weren't exposed to arsenic.

They found a significant decrease in the ability of the muscle in arsenic-exposed mice to regenerate after the injury, and a consequent impairment of muscle function. They examined muscle tissue after taking away all the cells, leaving only what's called the extracellular matrix, and found it had abnormally remodeled producing structural deficits.

The researchers seeded the arsenic-exposed extracellular matrix with human to see if healthy muscle would reform.

"We found that this pathogenic matrix impaired the ability of our to form new muscle fibers," Dr. Ambrosio said. "This may contribute to an impaired healing response after injury."

They learned that arsenic caused heightened biochemical signals from a protein complex called NF kappa B, which is involved in matrix remodeling and tissue repair.

"A striking finding is that if we blocked the activation of the NF kappa B program, we saw the arsenic-exposed recovered just fine," Dr. Barchowsky said. "We'd like to go deeper into this in our next steps to explore whether we can reverse 's impact on a person who has been chronically exposed to it."

Dr. Ambrosio, a physical therapist, noted that some patients have a harder time recovering from surgery or injury.

"From a rehabilitation perspective, it could be important to pay more attention to these environmental factors that may be influencing the ability of tissue to regenerate," she said. "It would be wonderful if we could identify people who may be predisposed to a diminished healing capacity and then intervene accordingly so they are able to better recover from injuries."

Explore further: Children exposed to arsenic may face greater risk of infection, respiratory symptoms

Related Stories

Children exposed to arsenic may face greater risk of infection, respiratory symptoms

November 9, 2015
Children born to women who were exposed to higher arsenic during pregnancy have a greater risk of infections and respiratory symptoms within their first year of life, a Dartmouth College-led study shows.

Low-level arsenic exposure before birth associated with early puberty and obesity

August 26, 2015
Female mice exposed in utero, or in the womb, to low levels of arsenic through drinking water displayed signs of early puberty and became obese as adults, according to scientists from the National Institutes of Health. The ...

Low doses of arsenic cause cancer in male mice

July 8, 2014
Mice exposed to low doses of arsenic in drinking water, similar to what some people might consume, developed lung cancer, researchers at the National Institutes of Health have found.

Placenta reflects arsenic exposure in pregnant women and fetuses, study shows

April 2, 2015
The placenta can be used to reliably measure arsenic exposure in pregnant women and how much of the toxic metal is transferred to their fetuses, a Dartmouth College study shows.

Researchers isolate human muscle stem cells

September 23, 2015
UC San Francisco researchers have successfully isolated human muscle stem cells and shown that the cells could robustly replicate and repair damaged muscles when grafted onto an injured site. The laboratory finding paves ...

Baby formula poses higher arsenic risk to newborns than breast milk, study shows

February 23, 2015
In the first U.S. study of urinary arsenic in babies, Dartmouth College researchers found that formula-fed infants had higher arsenic levels than breast-fed infants, and that breast milk itself contained very low arsenic ...

Recommended for you

How to survive on 'Game of Thrones': Switch allegiances

December 9, 2018
Characters in the Game of Thrones TV series are more likely to die if they do not switch allegiance, and are male, according to an article published in the open access journal Injury Epidemiology.

Expert calls for strong, sustainable action to make world roadways safer

December 7, 2018
According to the latest World Health Organization (WHO) report on road safety, more than 1.3 million people die on the world's roadways each year—and millions more are injured or disabled. Yet despite the huge cost to families ...

Hazelnuts improve older adults' micronutrient levels

December 6, 2018
Older adults who added hazelnuts to their diet for a few months significantly improved their levels of two key micronutrients, new research at Oregon State University indicates.

Regular bedtimes and sufficient sleep for children may lead to healthier teens

December 6, 2018
Having a regular, age-appropriate bedtime and getting sufficient sleep from early childhood may be important for healthy body weight in adolescence, according to researchers at Penn State.

Stress from using electronic health records is linked to physician burnout

December 5, 2018
While electronic health records (EHRs) improve communication and access to patient data, researchers found that stress from using EHRs is associated with burnout, particularly for primary care doctors such as pediatricians, ...

Chemicals in personal care and household products linked to earlier puberty in girls

December 4, 2018
Chemicals that are widely used in personal care and household products are linked to girls entering puberty at earlier ages, according to findings from a long-running study of mothers and children published today.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.