(NaturalNews) Arsenic exposure in the womb may hamper the body's ability to fight off later infection, according to a new study conducted by researchers from the Telethon Institute for Child Health Research in Australia and published in the journal Environmental Health Perspectives.
Arsenic, a known carcinogen and endocrine disruptor, is commonly found contaminating water supplies across the world. Although the U.S. Environmental Protection Agency limits its levels in drinking water to a maximum of 10 ppb, those regulations do not apply to well water. In recent years, concerns have also been raised over arsenic contamination of common foods including apple juice, rice and rice-based products. There are currently no regulations for maximum arsenic content in food.
Inorganic arsenic, the more toxic form, has been linked to hampered immune responses and altered gene expression in the lungs. It has also been connected with a number of respiratory illnesses including chronic bronchitis and chronic obstructive pulmonary disease.
In lung cancer patients, early exposure to arsenic has also been linked with a chronic respiratory disease characterized by repeated lower respiratory infections and exaggerated respiratory inflammation. Over time, bronchiectasis can lead to further lung damage and even heart problems.
Damaging the immune response
An earlier study, conducted by researchers from Marine Biological Laboratory and Dartmouth Medical School and published in Environmental Health Perspectives in 2009, found that mice exposed to 100 ppb of arsenic for five weeks later had a very weak initial response to infection with the H1N1 flu strain.
"When a normal person or mouse is infected with the flu, they immediately develop an immune response in which immune cells rush to the lungs and produce chemicals that help fight the infection," researcher Joshua Hamilton said.
Notably, the exposed animals did experience a disproportionately strong response several days later, when it was too late to do any good.
"There was a massive infiltration of immune cells to the lungs and a massive inflammatory response, which led to bleeding and damage in the lung," Hamilton said.
In the new study, researchers exposed pregnant mice either to clean water or to water contaminated with 100 ppb of inorganic arsenic; after birth, the pups were given the same type of drinking water as their mothers. A week after birth, some of the pups were deliberately exposed to H3N1 influenza. The researchers found significantly higher viral titers and inflammatory responses among the mice exposed to both arsenic and influenza than the other mice. The arsenic- and influenza-exposed mice also had higher levels of inflammation and constriction in their airways.
"This is a great study that advances the field," said Bruce Stanton of Dartmouth College, who was not involved in the study. The findings suggest that early arsenic exposure may also predispose young human children and infants to later flu infection and lung damage, he said.
"We would like to combine arsenic exposure with repeated bacterial and viral infections to model the development of bronchiectasis throughout life," researcher Kathryn Ramsey said.
Hamilton suspects that part of the reason arsenic plays so much havoc with the immune system is its large-scale disruption of numerous hormone pathways.
"Most chemicals that disrupt hormone pathways target just one, such as the estrogen pathway," Hamilton said. "But arsenic disrupts the pathways of all five steroid hormone receptors (estrogen, testosterone, progesterone, glucocorticoids and mineralocorticoids), as well as several other hormone pathways. You can imagine that just this one effect could play a role in cancer, diabetes, heart disease, reproductive and developmental disorders - all the diseases that have a strong hormonal component."