- Press Release Distribution

Fetal exposure to PCBs affects hearing health later in life

Early exposure to the environmental chemical made it more difficult for mice to recover from sound-related trauma sustained later in life.

( Music, mice, and microscopic imaging combine to provide new insight into the effects of environmental chemicals on hearing loss.

Researchers at the Beckman Institute for Advanced Science and Technology found that early exposure to an environmental chemical called polychlorinated biphenyls, or PCBs, made it more difficult for mice to recover from sound-related trauma sustained later in life.

Their paper appears in the Journal of Neuroscience.

PCBs are carcinogenic compounds formerly used in industrial and consumer products. Although they were banned in the United States in 1979 and haven’t seen industrial use in decades, their highly stable chemical structure makes them difficult to eradicate from the environment. Exposure continues to this day and is most common through consumption of contaminated fish. In particular, exposure to PCBs can be harmful to a developing fetus.

“The most sensitive period in pregnancy for these types of developmental exposures is typically early in the pregnancy, in the first trimester,” said Dr. Daniel Llano, an associate professor in the Department of Molecular and Integrative Physiology at the University of Illinois Urbana-Champaign and the corresponding author on the paper. “But PCBs as chemical entities are very permeant to all sorts of membranes. They can cross the placenta and they can get into the brain. That makes them particularly dangerous throughout all phases of pregnancy.”

The groundwork for the research was laid several years ago by Susan Schantz, a professor emerita in the Department of Comparative Biosciences who was studying the effects of PCBs on the developing auditory system. She found that rats treated with PCBs experienced seizures in response to certain levels of sound.

This led to a collaboration among Schantz, Llano, and Baher Ibrahim, a research scientist in the Department of Molecular and Integrative Physiology and the lead author of the paper. Although the researchers had known for years that PCBs altered hearing, they wanted to understand how.

The researchers suspected that if an individual who was exposed to PCBs in utero sustained acoustic trauma later in life (for example, from an occupation associated with high noise levels, or even a recreational activity like a rock concert), their hearing might not recover as would typically be expected. 

Instead of continuing to study the auditory cortex, the researchers shifted focus to a lower brain region known as the inferior colliculus. There, they identified damage resulting from the combination of PCBs and noise.

They studied individual neurons in the animals’ brains with a technique called multiphoton imaging.

“This is a one-of-a-kind microscope, and we are one of very few labs in the world doing this particular kind of imaging in this brain region,” Llano said. “People have shown in the past that if you expose a mouse to loud sound, over time, the neurons in the inferior colliculus become hyper-responsive. But when combining the two toxic exposures, PCBs and noise, and using our imaging technique, that hyperexcitability went away."

The researchers also observed the neurons to become hypo-excitable — a brand-new finding.

The study team used chemical analysis to further understand the mechanisms behind these changes. Their findings centered around a common cellular process called oxidative stress that automatically releases oxygen radicals — or highly reactive chemicals — when cells are sick or exposed to toxins. Oxygen radicals are eliminated by an intrinsic system within the body.

Mice with higher levels of the intrinsic protective system suffered less damage to the inferior colliculus, suggesting that PCBs and noise could cause a surplus of oxidative stress in the inferior colliculus, suppressing the auditory system’s ability to recover from acoustic trauma.

“On its own, PCB exposure in utero may cause only a moderate degree of hearing loss,” Llano said. “But that PCB exposure creates a particular vulnerability to later hearing loss. And so someone who is exposed to PCBs during development and has a significant occupational or recreational exposure to sound later in life may suffer greater-than-expected consequences when it comes to hearing.”

Compared to many toxicology studies, which look at a single exposure, the Beckman research team accounted for two exposures — PCBs and noise — experienced in separate instances over the course of a lifespan.

“What we found were effects that would not have been predictable based on the separate impacts of the individual exposures,” Llano said. “You can’t necessarily predict the consequence of combined exposure to two environmental factors by adding up the effects of either one by itself. I think that’s one of the more interesting things about this study, and hopefully it can be used as a model for future toxicology studies.”

The study team will continue to investigate the connections among PCB exposure, noise exposure, and hearing loss. While oxidative stress appears to be a key mediator of the effect, investigators have yet to measure oxygen radicals in the tissues to confirm this.

“Dr. Llano and I have now co-mentored a graduate student and three postdocs who have carried this research forward,” Schantz said. “We are about to embark on the next stage of our collaboration, co-mentoring a fourth postdoc who will study the microvasculature of key brain regions after PCB and noise exposure.”

These research questions will continue to be explored exactly where the study began: at the Beckman Institute.

“This is the kind of study that could only occur at Beckman,” Llano said. “Dr. Schantz and I are in entirely different departments. Our home departments are in completely different locations on campus, but our Beckman offices are 10 feet apart. Because of that, it’s made it very easy for us to collaborate. I think this is the kind of study that would be almost impossible to do in a different environment where we didn’t have easy access to each other’s ideas and the various interactions that exist here.”

Editor's notes:

The paper titled "Developmental exposure to polychlorinated biphenyls prevents recovery from noise-induced hearing loss and disrupts the functional organization of the inferior colliculus" can be accessed online: 




Quantum computers are better at guessing, new study demonstrates

Daniel Lidar, the Viterbi Professor of Engineering at USC and Director of the USC Center for Quantum Information Science & Technology, and first author Dr. Bibek Pokharel, a Research Scientist at IBM Quantum, achieved this quantum speedup advantage in the context of a “bitstring guessing game.”  They managed strings up to 26 bits long, significantly larger than previously possible, by effectively suppressing errors typically seen at this scale. (A bit is a binary number that is either zero or one). Quantum computers promise to solve certain problems with an advantage that increases as the ...

New discoveries about where atherosclerotic plaques rupture can lead to preventive treatments

A common cause of myocardial infarction and stroke is the rupture of atherosclerotic plaques. The exact location of plaque ruptures has previously been unknown, but now researchers at Lund University have mapped this. The research team has also identified an enzyme, a marker, that they hope will help predict who is at risk of having a myocardial infarction or a stroke due to a ruptured atherosclerotic plaque.  In atherosclerosis , fat  is accumulated in the artery walls creating atherosclerotic ...

Webb Space Telescope detects universe’s most distant complex organic molecules

Webb Space Telescope detects universe’s most distant complex organic molecules
CHAMPAIGN, Ill. — Researchers have detected complex organic molecules in a galaxy more than 12 billion light-years away from Earth – the most distant galaxy in which these molecules are now known to exist. Thanks to the capabilities of the recently launched James Webb Space Telescope and careful analyses from the research team, a new study lends critical insight into the complex chemical interactions that occur in the first galaxies in the early universe. University of Illinois Urbana-Champaign astronomy and physics professor Joaquin Vieira and graduate student Kedar Phadke collaborated with researchers at Texas A&M ...

Zoonoses: Welcome to Professor Fernando Rosado Spilki, the new Executive Editor-in-Chief

As the Co-Editors-in-Chief of Zoonoses, Dr. Lynn Soong (University of Texas Medical Branch, TX, USA) and Dr. Xiaoping Dong (Chinese Center for Disease Control & Prevention, Beijing, China) extend a warm welcome to Dr. Fernando Rosado Spilki, new Executive Editor-in-Chief (Vector Biology/Epidemiology) of Zoonoses.   Dr. Spilki is currently a Professor in the Institute of Health Sciences at Feevale University, Novo Hamburgo, Brazil. He received B.S. in Veterinary Medicine (2001), M.S. in Veterinary Sciences/Animal Virology (2004) both from the Universidade Federal do Rio Grande do Sul, and his Ph.D. in Genetics & Molecular ...

Fungi stores a third of carbon from fossil fuel emissions and could be essential to reaching net zero, new study reveals

Fungi stores a third of carbon from fossil fuel emissions and could be essential to reaching net zero, new study reveals
Fungi stores a third of carbon from fossil fuel emissions and could be essential to reaching net zero, new study reveals Mycorrhizal fungi are responsible for holding up to 36 per cent of yearly global fossil fuel emissions below ground - more than China emits each year The fungi make up a vast underground network all over the planet underneath grasslands and forests, as well as roads, gardens, and houses on every continent on Earth It is not only crucial to storing carbon and keeping the planet cooler, but are also essential to global biodiversity  Researchers ...

Climate justice: Global North owes $170 trillion for excessive CO2 emissions, says study

Climate justice: Global North owes $170 trillion for excessive CO2 emissions, says study
Industrialised nations responsible for excessive levels of carbon dioxide emissions could be liable to pay a total of $170 trillion in compensation or reparations by 2050 to ensure climate change targets are met, say researchers.  This money, which amounts to nearly $6 trillion per year or about 7% of annual global Gross Domestic Product (GDP), would be distributed as compensation to low-emitting countries that must decarbonise their economies far more rapidly than would otherwise be required.  Financial redress for the losses and damages that climate-vulnerable countries face due to the excessive CO2 emissions of others is seen as an increasingly important ...

BRIDGEcereal: Self-teaching web app improves speed, accuracy of classifying DNA variations among cereal varieties

BRIDGEcereal: Self-teaching web app improves speed, accuracy of classifying DNA variations among cereal varieties
Kim Kaplan 301-588-5314   BRIDGEcereal: Self-Teaching Web App Improves Speed, Accuracy of Classifying DNA Variations Among Cereal Varieties PULLMAN, WA, June 5, 2023—Agricultural Research Service and Washington State University scientists have developed an innovative web app called BRIDGEcereal [] that can quickly and accurately analyze the vast amount of genomic data now available for cereal crops and organize the material into intuitive charts that identify patterns locating genes of interest. With the rapid advancements in ...

Availability of LGBTQ mental health services for youth

About The Study: This survey study found that 28% of youth-serving U.S. mental health facilities offered LGBTQ-specific mental health services in 2020. Although some states had relatively high levels of LGBTQ service availability as a percentage of facilities, many of these states had few facilities available to children per capita. Public mental health facilities were less likely to offer LGBTQ-specific mental health services, a concern given that the cost of care is a barrier to services. The findings suggest a need to expand availability of LGBTQ services ...

Can exercise help counteract genetic risk of disease?

New research has revealed being active could lower the risk of type 2 diabetes, even in people with a high genetic risk of developing the medical condition. The University of Sydney-led study found higher levels of total physical activity, especially moderate- to vigorous-intensity physical activity, had a strong association with a lower risk of developing type 2 diabetes. The findings were published in the British Journal of Sports Medicine. The researchers say the study demonstrates higher levels of physical activity should be promoted as a major strategy for type 2 diabetes ...

DNA sequencing in newborns reveals years of actionable findings for infants and families

Researchers who lead the world’s first comprehensive sequencing program for newborn infants have published the next chapter in the ongoing study of the BabySeq Project, with new findings on infants and families who have been followed for 3-5 years. In a study published today in the American Journal of Human Genetics, researchers from Mass General Brigham and Boston Children’s Hospital reported that over 10 percent of the first 159 infants to undergo screening through DNA sequencing were discovered ...


Bioinformatics approach could help optimize soldiers’ training for improved readiness and recovery

Earth scientists describe a new kind of volcanic eruption

Warmer wetter climate predicted to bring societal and ecological impact to the Tibetan Plateau

Feeding infants peanut products protects against allergy into adolescence

Who will like beetle skewers? What Europeans think about alternative protein food

ETRI wins ‘iF Design Award’ for mobile collaborative robot

Combating carbon footprint: novel reactor system converts carbon dioxide into usable fuel

Investigating the origin of circatidal rhythms in freshwater snails

Altering cellular interactions around amyloid plaques may offer novel Alzheimer’s treatment strategies

Brain damage reveals part of the brain necessary for helping others

Surprising properties of elastic turbulence discovered

Study assesses cancer-related care at US hospitals predominantly serving minority populations compared with non-minority serving hospitals

First in-human investigator-initiated clinical trial to launch for refractory prostate cancer patients: Novel alpha therapy targets prostate-specific membrane antigen

Will generative AI change the way universities communicate?

Artificial Intelligence could help cure loneliness, says expert

Echidnapus identified from an ‘Age of Monotremes’

Semaglutide may protect kidney function in individuals with overweight or obesity and cardiovascular disease

New technique detects novel biomarkers for kidney diseases with nephrotic syndrome

Political elites take advantage of anti-partisan protests to disrupt politics

Tiny target discovered on RNA to short-circuit inflammation, UC Santa Cruz researchers find

Charge your laptop in a minute? Supercapacitors can help; new research offers clues

Scientists discover CO2 and CO ices in outskirts of solar system

Theory and experiment combine to shine a new light on proton spin

PKMYT1, a potential ‘Achilles heel’ of treatment resistant ER+ breast cancers with the poorest prognosis

PH-binding motifs as a platform for drug design: Lessons from protease-activated receptors (PARs)

Virginia Tech researcher creates new tool to move tiny bioparticles

On repeat: Biologists observe recurring evolutionary changes, over time, in stick insects

Understanding a broken heart

Genetic cause of rare childhood immune disorders discovered

With wobbling stars, astronomers gauge mass of 126 exoplanets and find 15 new ones

[] Fetal exposure to PCBs affects hearing health later in life
Early exposure to the environmental chemical made it more difficult for mice to recover from sound-related trauma sustained later in life.