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Distinct Air Pollution Components and Sources Linked to Hippocampal Architecture in Pre-Adolescents

Poster No:

970

Submission Type:

Abstract Submission

Authors:

Michael Rosario¹, Kirthana Sukumaran¹, Katherine Bottenhorn¹, Devyn Cotter¹, Alethea de Jesus¹, Carlos Cardenas-Iniguez¹, Hedyeh Ahmadi¹, Jacob Pine², Deanna Barch², Megan Herting¹

Institutions:

¹Keck School of Medicine of USC, Los Angeles, CA, ²Washington University, Saint Louis, MO

First Author:

Michael Rosario, PhD
Keck School of Medicine of USC
Los Angeles, CA

Co-Author(s):

Kirthana Sukumaran, MS
Keck School of Medicine of USC
Los Angeles, CA

Katherine Bottenhorn, PhD
Keck School of Medicine of USC
Los Angeles, CA

Devyn Cotter, MS
Keck School of Medicine of USC
Los Angeles, CA

Alethea de Jesus
Keck School of Medicine of USC
Los Angeles, CA

Carlos Cardenas-Iniguez, PhD
Keck School of Medicine of USC
Los Angeles, CA

Hedyeh Ahmadi, PhD
Keck School of Medicine of USC
Los Angeles, CA

Jacob Pine, PhD
Washington University
Saint Louis, MO

Deanna Barch, PhD
Washington University
Saint Louis, MO

Megan Herting, PhD
Keck School of Medicine of USC
Los Angeles, CA

Introduction:

Ambient fine particulate air pollution (PM_2.5) and its sources pose significant risks to brain health. Studies have linked air pollution exposure to significant changes in brain structure and function, including alterations in subcortical volume and microstructural integrity¹. The hippocampus is particularly vulnerable to environmental insults; yet,the extent to which it is affected by air pollution during childhood and adolescence remains inadequately understood. Here, we aimed to characterize the effect of ambient fine particulate matter components and sources on hippocampal microstructure and long-axis volume.

Methods:

We used cross-sectional data from the United States' Adolescent Brain Cognitive Development (ABCD) Study to examine associations between air pollution exposure and hippocampal microstructure (n = 9,646, 9-11 years of age) and long-axis volume (n = 8,264), measured using magnetic resonance imaging. Fine air pollution estimates included fifteen constituent components of PM_2.5 (including organic chemicals, metals and dust particles) and six sources (biomass burning, industrial, traffic, ammonium sulfates, ammonium nitrates, and crustal), along with ozone and nitrogen dioxide. We conducted separate partial least squares correlation analyses in order to account for mixture effects of PM_2.5 components and sources, respectively. After accounting for potential confounding from demographic, socioeconomic, and neuroimaging variables, we applied partial least squares correlation analysis to assess the shared variance between simultaneous PM_2.5 component or source exposures with hippocampal microstructure and long-axis volume.

Results:

Greater exposure to organic carbon and ozone were associated with a pattern of lower total intracellular and higher total extracellular diffusion. Results from the source-based PLSC revealed a similar pattern, with higher levels of biomass burning (primarily made up of organic carbon, potassium, silica, and bromine) and ozone driving our results. Furthermore, increased exposure to organic carbon, copper, and zinc correlated with smaller volumes in the left hippocampal head and right hippocampal head, body, and tail. Additionally, simultaneous exposure to higher levels of industrial (lead, zinc, nickel) and traffic-related pollutants (copper, elemental carbon, and iron) were associated with smaller volumes in the left hippocampal head and tail and the right hippocampal head, body, and tail.

·Figure 1

·Figure 2

Conclusions:

Exposure to PM_2.5 components and to sources, along with ozone, was associated with distinct patterns of lower intracellular and higher extracellular diffusion in the hippocampus, as well as smaller hippocampal head, body, and tail volumes. The hippocampus is crucial for learning, memory, and emotional and stress regulation. Reducing air pollution exposure, especially by targeting specific harmful sources, could help mitigate the negative impacts on hippocampal health, thereby supporting cognitive and emotional well-being among children during a critical time in development.

Learning and Memory:

Long-Term Memory (Episodic and Semantic)

Lifespan Development:

Early life, Adolescence, Aging ¹

Modeling and Analysis Methods:

Multivariate Approaches

Segmentation and Parcellation

Neuroanatomy, Physiology, Metabolism and Neurotransmission:

Subcortical Structures ²

Keywords:

MRI

Multivariate

PEDIATRIC

Segmentation

STRUCTURAL MRI

Sub-Cortical

Other - Hippocampus

^1|2Indicates the priority used for review

Abstract Information

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Please indicate below if your study was a "resting state" or "task-activation” study.

Other

Healthy subjects only or patients (note that patient studies may also involve healthy subjects):

Healthy subjects

Was this research conducted in the United States?

Yes

Are you Internal Review Board (IRB) certified? Please note: Failure to have IRB, if applicable will lead to automatic rejection of abstract.

Yes, I have IRB or AUCC approval

Were any human subjects research approved by the relevant Institutional Review Board or ethics panel? NOTE: Any human subjects studies without IRB approval will be automatically rejected.

Yes

Were any animal research approved by the relevant IACUC or other animal research panel? NOTE: Any animal studies without IACUC approval will be automatically rejected.

Not applicable

Please indicate which methods were used in your research:

Structural MRI

Diffusion MRI

For human MRI, what field strength scanner do you use?

3.0T

Which processing packages did you use for your study?

Other, Please list - Data were obtained from the ABCD Study, and were preprocessed in FreeSurfer

Provide references using APA citation style.

1. 1. Morrel, J. et al. (2024). A systematic review of air pollution exposure and brain structure and function during development. medRxiv, 10.1101/2024.09.13.24313629.

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