Researchers at the University of Iowa have received $2.06 million funding from the National Institute of Environmental Health Sciences (NIEHS) to study the toxicology of airborne engineered nanomaterials.
Engineered nanomaterials (ENMs) are ultra-small man-made materials such as carbon nanotubes, silica-coated gold particles, graphine, and copper oxide particles that are used in an array of products to provide them with special characteristics including strength, flexibility, anti-microbial activity, and unique optical and electrical properties. Some ENMs serve as tiny packages for drug delivery in the body.
Peter Thorne, professor and head of occupational and environmental health at the UI College of Public Health, is the primary investigator on the study. His team also includes Drs. Andrea Adamcakova-Dodd and Patrick O’Shaughnessy from the UI College of Public Health along with Dr. Aliasger Salem from the UI College of Pharmacy.
Iowa is one of eight research sites nationwide participating in the study, each examining different aspects of ENM toxicity. The UI site will focus on inhalation of ENMs and developmental toxicology via cell-culture studies and multigenerational studies of laboratory mice.
According to Thorne, human exposure to ENMs can occur during manufacturing, product use, and disposal, but little is known about the effect on people. “The use of engineered nanomaterials is moving faster than the study of their toxicity,” he says. “By understanding the biological response profiles underlying their toxicity, it will be easier to predict which are likely to be hazardous.
“Our studies seek to determine if inhalation of novel ENMs during pregnancy can interfere with the immune or endocrine systems in ways that may harm the developing fetus,” Thorne says.
The researchers hope a better understanding of the toxicity of ENMs will help establish a framework for improving the safety profile of commercial ENMs and guide their safe and sustainable use.
Amish children’s exposures protect against asthma through reprogramming innate immunity
Iowa research finds house dust differences between communities affects immune development
By probing the differences between two farming communities—the Amish of Indiana and the Hutterites of South Dakota—an interdisciplinary team of researchers, including Peter Thorne, professor and head of the University of Iowa’s Department of Occupational and Environmental Health, found that specific aspects of the Amish environment are associated with changes to immune cells that protect children from developing asthma.
In the Aug. 4, 2016, issue of The New England Journal of Medicine, the researchers showed that substances in the house dust from Amish, but not Hutterite, homes were able to engage and shape the innate immune system (the body’s front-line response to most microbes) in young Amish children in ways that may suppress pathologic responses leading to allergic asthma. The study is available online.
While the Amish and Hutterite communities have a similar genetic ancestry and share similar lifestyles, customs, and diets, their farming practices differ. The Amish have retained traditional methods. They live on single-family dairy farms and rely on horses for fieldwork and transportation. In contrast, the Hutterites live on large communal farms and use modern, industrialized farm machinery. This distances young Hutterite children from the constant daily exposure to farm animals.
Another striking difference between the two communities is the large disparity in asthma cases. About 5 percent of Amish schoolchildren aged 6 to 14 have asthma. This is about half of the U.S. average (10.3%) for children aged 5 to 14, and one-fourth of the prevalence (21.3%) among Hutterite children.
To understand this disparity, the researchers studied 30 Amish children 7 to 14 years old, and 30 age-matched Hutterite children. They scrutinized the children’s genetic profiles, which confirmed the remarkable similarities between Amish and Hutterite children. They compared the types of immune cells in the children’s blood, collected airborne dust from Amish and Hutterite homes and measured the microbial load in homes in both communities.
Thorne’s group, which also included Dr. Nervana Metwali from the UI’s Department of Occupational and Environmental Health, deployed novel air samplers for the study that do not require electricity. These Electrostatic Dust Samplers were placed into Amish and Hutterite homes to measure airborne particles and toxins in order to assess differences in exposures between these populations.
Results of the study showed that dust collected from Amish homes was “much richer in microbial products,” the authors note, than dust from Hutterite homes.
Thorne explained, “When we administered extracts of the two types of dust to mice, we were able to reproduce the differences in respiratory allergy that we observed in the Amish and Hutterite children.”
“The study augments prior work showing the significant role our environmental exposures play in asthma,” Thorne said. “The big advance is how our study beautifully demonstrated the key role of innate immunity in asthma in two rural populations with similar genetics.
“This is a great example of a major discovery arising from a multidisciplinary team of scientists drawn from multiple universities,” Thorne added. “Each member of the team brought unique scientific knowledge to the research.”
The National Institutes of Health, National Institute of Environmental Health Sciences, the St. Vincent Foundation, and the American Academy of Allergy, Asthma & Immunology Foundation supported the study.
The study included researchers from the University of Chicago, the University of Arizona, Dr. von Hauner Children Hospital in Munich, Germany, and Allergy and Asthma Consultants, Indianapolis.
Barnyard Dust Offers a Clue to Stopping Asthma in Children (The New York Times)
Amish kids help scientists understand why farm life reduces the risk of asthma (Los Angeles Times)
How a Cow in Your Living Room Could Make the Difference for Asthma and Allergies (Iowa Public Radio)
Researchers at the University of Iowa recently reported the results of the largest study to date on the relationship between exposure to endotoxin and incidences of wheeze and asthma in children and adults. The study was a collaboration with researchers at the National Institute of Environmental Health Sciences and the National Center for Health Statistics.
Endotoxins are immune-modulating molecules found in the outer membrane of common bacteria that elicit inflammation in the airways of animals and humans.
According to research team leader Peter Thorne, professor and head of occupational and environmental health at the University of Iowa College of Public Health, the study showed that higher levels of endotoxin in dust samples were positively associated with an increased prevalence of active wheezing requiring medication and health care utilization.
“Everyone is exposed to some endotoxin,” Thorne says, “however, in this nationwide representative sample we showed that higher exposure would be expected to produce more severe wheezing in people both with and without allergy, producing more medication use and requiring more medical care.”
It was noteworthy that the relationship between endotoxin and wheezing did not exhibit a threshold, but showed a positive association over the entire range of values measured.
Thorne’s group tested endotoxin in bed and bedroom floor dust samples from almost 7,000 U.S. households using a novel approach that included unprecedented quality control measures. The participants were enrolled in the National Health and Nutritional Examination Survey (NHANES).
According to Thorne, endotoxin was found at higher concentrations in lower-income households and in households with carpet, children, pets, vermin, and smokers.
“The study shows the importance of improving the U.S. housing stock and educating people about the importance of controlling vermin, keeping a clean home. and eliminating indoor smoking.”
Results of the study were published in the December 2015 edition of the American Journal of Respiratory and Critical Care Medicine with an accompanying editorial. The full article is available here: http://www.atsjournals.org/doi/10.1164/rccm.201502-0251OC#.Vm8V5kZF0w8.