Influence of exposure to coarse, fine and ultrafine urban particulate matter and their biological constituents on neural biomarkers in a randomized controlled crossover study
Bibliographic record
Abstract
Background Epidemiological studies have reported associations between air pollution and neuro-psychological conditions. Biological mechanisms behind these findings are still not clear. Objectives We examined changes in blood and urinary neural biomarkers following exposure to concentrated ambient coarse, fine and ultrafine particles. Methods Fifty healthy non-smoking volunteers, mean age 28 years, were exposed to coarse (2.5–10 μm, mean 213 μg/m 3 ) and fine (0.15–2.5 μm, mean 238 μg/m 3 ) concentrated ambient particles (CAPs), and filtered ambient and/or medical air. Twenty-five participants were exposed to ultrafine CAP (mean size 59.6 nm, range 47.0–69.8 nm), mean (136 μg/m 3 ) and filtered medical air. Exposures lasted 130 min, separated by ≥ 2 weeks, and the biological constituents endotoxin and β-1,3- d -glucan of each particle size fraction were measured. Blood and urine samples were collected pre-exposure, and 1-hour and 21-hour post-exposure to determine neural biomarker levels. Mixed-model regressions assessed associations between exposures and changes in biomarker levels. Results Results were expressed as percent change from daily pre-exposure biomarker levels. Exposure to coarse CAP was significantly associated with increased urinary levels of the stress-related biomarkers vanillylmandelic acid (VMA) and cortisol when compared with exposure to filtered medical air [20% (95% confidence interval: 1.0%, 38%) and 64% (0.2%, 127%), respectively] 21 hours post-exposure. However exposure to coarse CAP was significantly associated with decreases in blood cortisol [− 26.0% (− 42.4%, − 9.6%) and − 22.4% (− 43.7%, − 1.1%) at 1 h and 21 h post-exposure, respectively]. Biological molecules present in coarse CAP were significantly associated with blood biomarkers indicative of blood brain barrier integrity. Endotoxin content was significantly associated with increased blood ubiquitin C-terminal hydrolase L1 [UCHL1, 11% (5.3%, 16%) per ln(ng/m 3 + 1)] 1-hour post-exposure, while β-1,3- d -glucan was significantly associated with increased blood S100B [6.3% (3.2%, 9.4%) per ln(ng/m 3 + 1)], as well as UCHL1 [3.1% (0.4%, 5.9%) per ln(ng/m 3 + 1)], one-hour post-exposure. Fine CAP was marginally associated with increased blood UCHL1 when compared with exposure to filtered medical air [17.7% (− 1.7%, 37.2%), p = 0.07] 21 hours post-exposure. Ultrafine CAP was not significantly associated with changes in any blood and urinary neural biomarkers examined. Conclusion Ambient coarse particulate matter and its biological constituents may influence neural biomarker levels that reflect perturbations of blood-brain barrier integrity and systemic stress response.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.005 | 0.005 |
| Meta-epidemiology (narrow) | 0.002 | 0.001 |
| Meta-epidemiology (broad) | 0.004 | 0.002 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.002 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.002 | 0.002 |
| Insufficient payload (model declined to judge) | 0.007 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".