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Why Are Urban Children More Prone to Allergies?

Monday, May 12, 2025

Study Finds Unique Immune Cell Linked to Risk

Scientists discovered that a previously uncharacterized subset of immune cells may play a critical role in the development of allergic diseases and explain differences between urban and rural populations. The finding, published in the journal Allergy, provides new insight into how the immune system is shaped in early life—and why urban children are more prone to allergies than children from rural areas. 

Led by researchers from the University of Rochester Medical Center (URMC) Department of Pediatrics, including MD/PhD student Catherine Pizzarello and senior author Kirsi Järvinen-Seppo, MD, PhD, the study uncovered a unique subpopulation of T cells known as helper 2 (Th2) cells with distinct molecular characteristics. 

T-cells are the foundational immune cells that fight off infections, but there is evidence that this specific subtype is recognizing certain foods as allergenic and attacking them, according to Jarvinen-Seppo. 

“These pro-allergic T cells are more inflammatory than anything previously described in this context,” said Järvinen-Seppo, chief of Pediatric Allergy and Immunology at UR Medicine Golisano Children’s Hospital. “They were found more frequently in urban infants who later developed allergies, suggesting they may be a predictive biomarker or even a mechanistic driver of allergic disease.” 

The study compared blood samples from urban infants with those from infants in a farming community, specifically the Old Order Mennonites (OOM) of New York’s Finger Lakes region—known for their low rates of allergies. Researchers found that while urban infants had higher levels of the aggressive Th2 cells, OOM infants had more regulatory T cells that help keep the immune system in balance and reduce the likelihood of allergic responses. 

While additional research is needed to identify a possible cause, Jarvinen-Seppo speculates that differences in the development of the gut microbiome between the two populations, and more exposure to “healthy” bacteria in rural children, may be a factor. 

“The farming environment, which is rich in microbial exposure, appears to support the development of a more tolerant immune system. Meanwhile, the urban environment may promote the emergence of immune cells that are primed for allergic inflammation,” said Jarvinen-Seppo. 

10 small things neurologists wish you’d do for your brain

Thursday, April 3, 2025

There’s growing research linking air pollution exposure to cognitive decline; scientists think very fine, inhalable particles in the air could trigger chemical changes once they reach the brain, says Deborah Cory-Slechta, a professor of environmental medicine and of neuroscience. She adds that wearing an N95 or surgical mask and using indoor air filters on days when air quality is worse (including because of wildfire smoke) can minimize your exposure.

Dr. Elder featured in Nature: "Your brain is full of microplastics: are they harming you?"

Tuesday, February 11, 2025

Plastics might affect each organ or cell type differently. The dose matters, too, as well as the route of ingestion, says Alison Elder, an associate professor of environmental medicine. “The inhalation route is a major concern because if inhaled plastics can get into the deep lung and cause an inflammatory reaction, they don’t need to go anywhere to cause health outcomes.”

70 countries have banned this pesticide. It’s still for sale in the US

Wednesday, January 22, 2025

The Washington Post, January 22

“The data is the data,” says Deborah Cory-Slechta, a professor of environmental medicine and of neuroscience. She says paraquat exposure is associated with the loss of dopamine neurons, which can cause slow and uncoordinated movements, tremors, and difficulty communicating, all of which are consistent with Parkinson’s disease.

“The evidence is very strong, both based on animal studies and on epidemiological evidence the fact that it kills dopamine neurons,” she said.

Biotin May Shield Brain from Manganese Damage, Study Finds

Tuesday, January 21, 2025

While manganese is essential in many bodily functions, both deficiency and excessive exposure can cause health issues. Maintaining a balanced diet typically provides sufficient manganese for most individuals; however, high levels of exposure can be toxic, particularly to the central nervous system. Chronic manganese exposure may result in a condition known as manganism, characterized by symptoms resembling Parkinson's disease, including tremors, muscle stiffness, and cognitive disturbances.

New research published in Science Signaling employs model systems and human nerve cells to show the mechanisms by which manganese inflicts damage to the central nervous system. The study also suggests that the vitamin biotin may be protective, potentially mitigating manganese-induced damage.

“Exposure to neurotoxic metals like manganese has been linked to the development of Parkinsonism,” said Sarkar Souvarish, PhD, an assistant professor at the University of Rochester Medical Center (URMC) Departments of Environmental Medicine and Neuroscience and lead author of the study. “In this study, we applied untargeted metabolomics using high-resolution mass spectrometry and advanced cheminformatics computing in a newly developed model of parkinsonism, leading us to the discovery of biotin metabolism as a modifier in manganese-induced neurodegeneration.”

Air pollution and brain damage: what the science says

Tuesday, January 14, 2025

Post-mortem studies of human brains provide direct evidence that numerous pollutants—including nanoparticles and toxic metals—accumulate in brain tissue. Deborah Cory-Slechta, a professor of environmental medicine and of neuroscience, says she suspects that the brain can’t cope with the resulting metal concentrations, noting that, for decades, pathologists have seen elevated levels of various metals in the brains of people with neurodegenerative diseases. She is now studying how the metals disrupt brain chemistry.