Rodent study finds artificial butter chemical harmful to lungs

A new study shows that exposure to a chemical called diacetyl, a component of artificial butter flavoring, can be harmful to the nose and airways of mice. Scientists at the National Institute of Environmental Health Sciences (NIEHS), part of the National Institutes of Health, conducted the study because diacetyl has been implicated in causing obliterative bronchiolitis (OB) in humans. OB is a debilitating but rare lung disease, which has been detected recently in workers who inhale significant concentrations of the flavoring in microwave popcorn packaging plants.

When laboratory mice inhaled diacetyl vapors for three months, they developed lymphocytic bronchiolitis - a potential precursor of OB. None of the mice, however, were diagnosed with OB.

“This is one of the first studies to evaluate the respiratory toxicity of diacetyl at levels relevant to human health. Mice were exposed to diacetyl at concentrations and durations comparable to what may be inhaled at some microwave popcorn packaging plants,” said Daniel L. Morgan, Ph.D., head of the Respiratory Toxicology Group at the NIEHS and co-author on the paper that appears online in the journal, Toxicological Sciences. The study was done in collaboration with Duke University researchers.

The authors conclude that these findings suggest that workplace exposure to diacetyl contributes to the development of OB in humans, but more research is needed.

Although exposure of laboratory animals by inhalation closely duplicates the way humans are exposed to airborne toxicants, the study points out that some anatomical differences between the mice and humans may account for why the nasal cavity of mice is more susceptible to reactive vapors than that of humans. Another reason may be that mice breathe exclusively through their noses.

The researchers also speculate that the extensive reaction of diacetyl vapors in the nose and upper airways of mice may have prevented toxic concentrations from penetrating deeper in the lung to the bronchioles or tiny airways where obstruction occurs in humans.

When the mice were exposed to high concentrations of diacetyl using a method that bypasses the nose, the researchers found lesions partially obstructing the small airways. More studies are under way to determine if these lesions progress to OB in mice.

The National Toxicology Program, headquartered at the NIEHS, plans to do a larger set of studies to provide inhalation toxicity data on artificial butter flavoring and the two major components, diacetyl and another compound called acetoin. The NTP studies will help pinpoint more definitively the toxic components of artificial butter flavoring and potentially help identify biomarkers for early detection. The NTP data will then be shared with public health and regulatory agencies so they can set safe exposure levels for these compounds and develop guidance to protect the health of workers in occupations where these chemicals are used.

Source: National Institute of Environmental Health Sciences

Related stories:

Anti-cancer drug prevents, reverses cardiovascular damage in mouse model of premature aging disorder
An experimental anti-cancer drug can prevent -- and even reverse -- potentially fatal cardiovascular damage in a mouse model of progeria, a rare genetic disorder that causes the most dramatic form of human premature aging, National Institutes of Health (NIH) researchers reported today.
Form of Crohn's disease traced to disabled gut cells
Scientists report online this week in Nature that they have linked the health of specialized gut immune cells to a gene associated with Crohn's disease, an often debilitating and increasingly prevalent inflammatory bowel disorder.
6 environmental research studies reveal critical health risks from plastic
Exposure to Bisphenol A (BPA), phthalates and flame retardants (PBDEs) are strongly associated with adverse health effects on humans and laboratory animals. A special section in the October 2008 issue of Environmental Research, "A Plastic World" provides critical new research on environmental contaminants and adverse reproductive and behavioral effects.
Research team discovers brain pathway responsible for obesity
University of Wisconsin-Madison researchers, for the first time, have found a messaging system in the brain that directly affects food intake and body weight.
When particles are so small that they seep right through skin
Scientists are finding that particles that are barely there – tiny objects known as nanoparticles that have found a home in electronics, food containers, sunscreens, and a variety of applications – can breech our most personal protective barrier: The skin.
Scientists discover why a mother's high-fat diet contributes to obesity in her children
New research published online in The FASEB Journal suggests that pregnant women should think twice about high-fat foods. In a study from the University of Cincinnati and the Medical College of Georgia, scientists found that female mice fed high fat diets were more likely to have oversized offspring (a risk factor for overweight and obesity) because fat causes the placenta to go into "overdrive" by providing too many nutrients to the fetus. This information also suggests that the reverse may be true as well—high fat diets may help prevent undersized babies.
Important new step toward producing stem cells for human treatment
(PhysOrg.com) -- A team of Harvard Stem Cell Institute (HSCI) scientists has taken an important step toward producing induced pluripotent stem (iPS) cells that are safe to transplant into patients to treat diseases.
Researchers note differences between people and animals on calorie restriction
Calorie restriction, a diet that is low in calories and high in nutrition, may not be as effective at extending life in people as it is in rodents, according to scientists at Washington University School of Medicine in St. Louis.

News discussion:

Medicine & Health news