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Event
Thu 9/19/2019 11:00AM - 12:00PM
EOH Journal Club
Particle Depletion Does Not Remediate Acute Effects of Traffic-related Air Pollution and Allergen EOH Journal Club
Particle Depletion Does Not Remediate Acute Effects of Traffic-related Air Pollution and Allergen
Thu 9/19/2019 11:00AM - 12:00PM
4140 Public Health, Young Seminar Room

Presenter: Brandy Hill

Paper: Particle Depletion Does Not Remediate Acute Effects of Traffic-related Air Pollution and Allergen. A Randomized, Double-Blind Crossover Study

Authors: Denise J. Wooding, Min Hyung Ryu, Anke Huls, Andrew D. Lee, David T. S. Lin, Christopher F. Rider, Agnes C. Y. Yuen, and Chris Carlsten

Abstract:
Rationale: Diesel exhaust (DE), an established model of trafficrelated
air pollution, contributes significantly to the global burden of
asthma and may augment the effects of allergen inhalation. Newer
diesel particulate-filtering technologies may increaseNO2 emissions,
raising questions regarding their effectiveness in reducing harm from
associated engine output.

Objectives: To assess the effects of DE and allergen coexposure on
lung function, airway responsiveness, and circulating leukocytes, and
determine whether DE particle depletion remediates these effects.

Methods: In this randomized, double-blind crossover study, 14
allergen-sensitized participants (9 with airway hyperresponsiveness)
underwent inhaled allergen challenge after 2-hour exposures to DE,
particle-depleted DE (PDDE), or filtered air. The control condition
was inhaled saline after filtered air. Blood sampling and spirometry
were performed before and up to 48 hours after exposures. Airway
responsiveness was evaluated at 24 hours.

Measurements and Main Results: PDDE plus allergen
coexposure impaired lung function more than DE plus allergen,
particularly in those genetically at risk. DE plus allergen and PDDE
plus allergen each increased airway responsiveness in normally
responsive participants.DEplus allergen increased blood neutrophils
and was associated with persistent eosinophilia at 48 hours. DE and
PDDE each increased total peripheral leukocyte counts in a manner
affected by participant genotypes. Changes in peripheral leukocytes
correlated with lung function decline.

Conclusions: Coexposure to DE and allergen impaired lung
function, which was worse after particle depletion (which increased
NO2). Thus, particulates are not necessarily the sole or main
culprit responsible for all harmful effects of DE. Policies and
technologies aimed at protecting public health should be scrutinized
in that regard.
Clinical trial registered with www.clinicaltrials.gov (NCT02017431).

Keywords: diesel exhaust; asthma; filter; genetic susceptibility


4140 Public Health, Young Seminar Room

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EOH Journal Club Seminar - Spring 2016 Date: Thursday February 25, 2016 Time: 11am - 12pm Presenter: Cody Wolfe Paper: TREM2 sustains microglial expansion during aging and response to demyelination Authors: Poliani PL, Wang Y, Fontana E, Robinette ML, Yamanishi Y, Gilfillan S, Colonna M. Abstract: Microglia contribute to development, homeostasis, and immunity of the CNS. Like other tissue-resident macrophage populations, microglia express the surface receptor triggering receptor expressed on myeloid cells 2 (TREM2), which binds polyanions, such as dextran sulphate and bacterial LPS, and activates downstream signaling cascades through the adapter DAP12. Individuals homozygous for inactivating mutations in TREM2 exhibit demyelination of subcortical white matter and a lethal early onset dementia known as Nasu-Hakola disease. How TREM2 deficiency mediates demyelination and disease is unknown. Here, we addressed the basis for this genetic association using Trem2(-/-) mice. In WT mice, microglia expanded in the corpus callosum with age, whereas aged Trem2(-/-) mice had fewer microglia with an abnormal morphology. In the cuprizone model of oligodendrocyte degeneration and demyelination, Trem2(-/-) microglia failed to amplify transcripts indicative of activation, phagocytosis, and lipid catabolism in response to myelin damage. As a result, Trem2(-/-) mice exhibited impaired myelin debris clearance, axonal dystrophy, oligodendrocyte reduction, and persistent demyelination after prolonged cuprizone treatment. Moreover, myelin-associated lipids robustly triggered TREM2 signaling in vitro, suggesting that TREM2 may directly sense lipid components exposed during myelin damage. We conclude that TREM2 is required for promoting microglial expansion during aging and microglial response to insults of the white matter.

Last Updated On Monday, March 21, 2016 by GSPH Webmaster
Created On Monday, March 21, 2016

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