Circadian Rhythm Disruption Effects on Smoke Inhalation

The Effects of Circadian Rhythm Disruption on the Inflammatory Response to Particulate Matter Exposure From Woodsmoke

Particulate matter exposure during smoke inhalation provokes inflammatory immune responses in people exposed to burning biomass including fire fighters and civilians. Persistent occupational exposure to particulate matter represents a unique hazard for firefighters, underpinning a burgeoning research area. This trial will evaluate the effects of sleep deprivation and circadian rhythm disruption on the inflammatory response to woodsmoke associated particulate matter exposure. Participants will undergo 2 experimental trials in a randomized cross-over design. Participants will have either an 8-hour sleep opportunity or a 4-hour sleep opportunity prior to reporting to lab for a 45 minute simulated firefighting trial (wood smoke associated particulate matter filtered to 2.5 um at a concentration of 250 ug/m^3, while exercising at a moderate intensity). The effects of sleep restriction and simulated firefighting will be measured.

Study Overview

• Status: Completed
• Conditions: Inflammation; Sleep Deprivation; Smoke Inhalation; Circadian Rhythm Sleep Disorder, Shift Work Type
• Intervention / Treatment: Behavioral: Normal Sleep; Behavioral: Sleep Restriction

Detailed Description

Participants: Healthy college age males (n = 15), free from disordered sleep and without recent trans-meridian travel (within the last 2 weeks) will be recruited for this study. Participants will complete chronotype questionnaires (Morningness-Eveningness Questionnaire; MEQ, Munich Chronotype Questionnaire; MCTQ) to establish intermediate chronotypes. This will minimize the effect of circadian preference on the morning exposure to smoke. Participants will subsequently be outfitted with activity monitors (ActiCal) to monitor sleep and physical activity throughout the experimental duration. Participants will be asked to maintain a normal sleep schedule for at least 3 days leading up to the experimental trials and keep a sleep log to verify.

Experimental Trials: Participants will undergo 2 experimental trials in a randomized cross-over design, with at least 1 week washout period between trials; 1) NS-250: Normal Sleep with exposure to woodsmoke at 250 µg/m^3, and RS-250: Restricted Sleep with exposure to woodsmoke at 250 µg/m^3. Participants will have an 8-hour sleep opportunity in their own home during the NS trials (22:00-06:00), and a 4-hour sleep opportunity during the RS trials (00:00-04:00). In all trials, participants will report to the laboratory at 07:30 the morning after the experimental sleep night. PM exposure will occur from 08:00-08:45 while cycling at 70% heart rate reserve (HRR) to simulate the physical demands of firefighting.

Exhaled Breath Condensate (EBC): EBC will be collected using standardized 10 minute collection techniques. In order to preserve sample integrity for potentially labile biomarkers (e.g., oxidative stress), sample pH will be measured immediately prior to aliquoting in multiple cryotubes (500-700µl), flash freezing, and storage at -80 degrees C until further assay. Standardized biomarker panels for oxidative stress and inflammation will be performed using a single thaw approach.

Inflammatory biomarker analysis: Blood will be collected into heparinized vacutainers before (PRE) and immediately following (POST) PM2.5 exposure and spun down for plasma collection. Plasma will be assayed for inflammatory biomarkers (interleukin (IL)-6, tumor necrosis factor (TNF)-α, pentraxin-3, and C-reactive protein (CRP)) using standard enzyme linked immunosorbent assays (ELISA).

Circadian Rhythm Assessment: Throughout the experimental protocol, circadian rhythms will be assessed in two ways; 1) Actigraphy and 2) Clock gene expression in buccal cell swabs. Acticals will be worn throughout to gather sleep variables (timing, duration, quality). Clock gene expression (CLOCK, BMAL1, PER2) will be measured in swabs taken from the cheek at 6 hour intervals (00:00, 06:00, 12:00, 18:00) to assess the effects of sleep deprivation on the molecular circadian rhythm. Cheek swabs will be immediately placed in RNA stabilization buffer until isolation. Swabs taken at 00:00 will be performed with minimal exposure to light to avoid disruption of sleep. These methods have been used previously to assess normal and disrupted sleep.

• Study Type: Interventional
• Enrollment (Actual): 10
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Montana
    • Missoula, Montana, United States, 59812
      • School of Integrative Physiology and Athletic Training

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 44 years (Adult)
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Healthy
• Male
• 18 - 44 years of age

Exclusion Criteria:

• Preexisting cardiometabolic and/or pulmonary diseases
• Preexisting sleep disorder
• Smoking (current or within last year)

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Placebo Comparator: Normal Sleep (with 250 ug/m^3 PM2.5); Participants will have a normal sleep opportunity the night prior to reporting to the lab for the simulated firefighting session (250 ug/m^3 PM2.5 with moderate intensity exercise).	Behavioral: Normal Sleep; Participants will be allowed ~8 hour sleep opportunity the night of sleep prior to reporting to lab for a simulated firefighting session.; Other Names: NS
Experimental: Restricted Sleep (with 250 ug/m^3 PM2.5); Participants will have a restricted sleep opportunity (~4 hours) the night prior to reporting to the lab for the simulated firefighting session (250 ug/m^3 PM2.5 with moderate intensity exercise).	Behavioral: Sleep Restriction; Participants will be allowed ~4 hour sleep opportunity during the restricted night of sleep prior to reporting to lab for a simulated firefighting session.; Other Names: SR; Circadian Rhythm Disruption

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Blood Inflammation	IL-6 will be measured in the plasma	samples collected at baseline, immediately post exposure

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Exhaled Breath Condensate Pentraxin-3	Pentraxin-3 will be measured in EBC of participants at baseline (PRE) and after exercise (POST) on two trial days. One trial day will be after a normal night of sleep (Normal Sleep) and the other trial will be after sleep restriction to 4 hours (Restricted Sleep). The value is determined through ELISA method, represented in ng/mL, where higher levels indicate worse response.	samples collected at baseline, immediately post exposure

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Circadian clock gene expression disruption	Clock genes will be measured over a 24 hour time-course with and without sleep restriction	sampled collected every 6 hours for 24 hours prior to exposure

Collaborators and Investigators

• Sponsor: University of Montana
• Collaborators: University of Nevada, Las Vegas
• Investigators: Principal Investigator: John C Quindry, PhD, University of Montana

Study record dates

Study Major Dates

• Study Start (Actual): January 24, 2022
• Primary Completion (Actual): March 17, 2022
• Study Completion (Actual): April 17, 2022

Study Registration Dates

• First Submitted: June 21, 2021
• First Submitted That Met QC Criteria: July 7, 2021
• First Posted (Actual): July 8, 2021

Study Record Updates

• Last Update Posted (Actual): May 30, 2025
• Last Update Submitted That Met QC Criteria: May 12, 2025
• Last Verified: May 1, 2025

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Neurologic Manifestations; Nervous System Diseases; Mental Disorders; Wounds and Injuries; Pathologic Processes; Respiratory Tract Diseases; Respiration Disorders; Dyssomnias; Chronobiology Disorders; Occupational Diseases; Burns; Burns, Inhalation; Inflammation; Respiratory Aspiration; Sleep Wake Disorders; Sleep Disorders, Circadian Rhythm; Sleep Deprivation; Smoke Inhalation Injury
• Other Study ID Numbers: IRB# is 83-21

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: Individual participant data will not be shared with other researchers. Blinded anonymized outcomes data will be shared via publication and presentation of results.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No