Brian Imaging Study Shows Amyloidosis in Some WTC Responders

Stony Brook-led research published in the Journal of Alzheimer's Disease

Closing in on 25 years since the World Trade Center (WTC) attacks, WTC responders continue to suffer long-term effects from their exposures at Ground Zero. One issue of possible growing concern is signs of early dementia in responders. The results of a new brain imaging study led by researchers at Stony Brook Medicine indicates a link between WTC exposure duration and the presence of amyloid in the brain.

Amyloid is a protein in the body that can form abnormal deposits in tissues and organs. These deposits can build up, cause a condition called amyloidosis, and are associated with numerous diseases, one of which is Alzheimer's disease. Many Alzheimer's patients have high levels of amyloid in areas of the brain. This study, published early online in the Journal of Alzheimer's Disease, included scans of the cerebrum of 35 WTC responders (26 men and 9 women), with an average age of 56 years.

"The take home point with this study is that we saw from the imaging that duration of WTC exposures had a direct link to amyloid in the brain, specifically in the olfactory cortex," said Sean Clouston, lead author and professor in the Department of Family, Population and Preventive Medicine in the Renaissance School of Medicine (RSOM), and in the Program of Public Health at Stony Brook University.

These composite brain images from the study of WTC responders reveal evidence of amyloidosis. Areas shaded in red and yellow indicate regions of the brain with amyloid. Credit: Sean Clouston, Stony Brook Medicine

Clouston stressed the study showed that WTC responders who were exposed for a lengthy period of time and who did not wear masks at Ground Zero had notable evidence of amyloid in the olfactory regions of the brain.

"It is also important to emphasize that the presence of amyloid was associated with cognitive impairment in this cohort," added Benjamin Luft, co-author, the Edmund D. Pellegrino Professor of Medicine in the RSOM and director of the Stony Brook WTC Health and Wellness Program. Nearly half of the subjects (17) showed cognitive impairment based on a standard battery of tests.

Both positron emission tomography (PET) and magnetic resonance imaging (MRI) scans were completed on the volunteer patients over three years. These patients are monitored for their health at the Stony Brook WTC Program.

WTC exposures included several inhaled exposures to fine particulate matter and air pollutants such as polycyclic aromatic hydrocarbons and dioxins.

The research team found that responders exposed to these elements via their worksites for months without a mask had a heightened burden of amyloidosis in the olfactory cortex. Additionally, when comparing non-masked to masked responders, the brain imaging also showed that high levels of amyloid in the olfactory cortex was associated with more amyloid throughout the brain.

The authors write that "amyloidosis is concerning because it implies the presence of aging-related amyloidosis at younger ages. Findings imply that exposure to air pollution may be a cause of a novel form of neuropathology in severely and chronically exposed individuals. If true, then efforts to remediate workplace exposures and protect workers might reduce the long-term burden of dementia in the population."

Clouston and colleagues point out that amyloidosis in this population may not cause Alzheimer's, though the association between cerebral amyloidosis and these conditions is strong. They hope to advance the research with larger patient cohorts and additional brain scans over time.

The research was funded in part by support from the Centers of Disease Control and Prevention and the National Institute for Occupational Safety and Health, grants U01 OH011314 and 75D301-22-C-15522, and the National Institute on Aging, grants R01 AG049953, R01 AG067590 and P30 AG066514.

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