Airway Hyperresponsiveness, Airway Inflammation, Asthma (Diagnosis)
Conditions
Keywords
Astaxanthin, Mild-to-Moderate Asthma, Air Pollution, FeNO, Hypertonic Saline Challenge, Impulse Oscillometry, Thoracic Bioelectrical Impedance Spectroscopy
Brief summary
This study will test whether astaxanthin, a naturally occurring antioxidant supplement, can improve lung function, reduce airway inflammation, and improve asthma control in adults with mild-to-moderate asthma. Participants will receive astaxanthin and placebo in random order in a double-blind crossover design. Each treatment period lasts 4 weeks and is separated by a 3-week washout period. The study also measures indoor and personal air pollution exposure to examine whether pollution influences asthma symptoms, airway responsiveness, and response to treatment. Exploratory thoracic bioelectrical impedance spectroscopy will be assessed alongside standard respiratory tests.
Detailed description
This is a randomized, double-blind, placebo-controlled, 2-sequence, 2-period crossover trial in 25 non-smoking, non-vaping adults aged 18 to 59 years with mild-to-moderate asthma or asthma-like symptoms confirmed at screening. Participants will be allocated 1:1 to one of two treatment sequences: astaxanthin followed by placebo, or placebo followed by astaxanthin. Each intervention period lasts 4 weeks and is separated by a 3-week washout. Astaxanthin will be given orally at a total dose of 12 mg/day as three 4 mg capsules taken with the participant's largest meal; placebo capsules will be matched. Outcome assessments include FeNO, spirometry, impulse oscillometry, body plethysmography, hypertonic saline challenge with induced sputum collection, home peak expiratory flow monitoring, questionnaires, and exploratory thoracic bioelectrical impedance spectroscopy. Indoor and personal air pollution exposures will be measured throughout the study to evaluate whether pollution modifies respiratory outcomes and treatment response.
Interventions
DIETARY_SUPPLEMENTAstaxanthin Oral Capsule
Natural astaxanthin derived primarily from Haematococcus pluvialis, administered orally as three 4 mg capsules daily (total 12 mg/day) with the participant's largest meal for 4
DIETARY_SUPPLEMENTMatched Placebo (Capsules)
Matched placebo capsules administered orally once daily as three capsules with the participant's largest meal for 4 weeks.
Sponsors
Middlesex University
AstaReal
BodyStat Ltd.
British Pest Control Association
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
TREATMENT
Masking
QUADRUPLE (Subject, Caregiver, Investigator, Outcomes Assessor)
Intervention model description
Two-sequence, two-period crossover design. Participants are randomized 1:1 to Sequence A (astaxanthin then placebo) or Sequence B (placebo then astaxanthin). Each treatment period lasts 4 weeks and is separated by a 3-week washout period.
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
Yes
Inclusion criteria
* Adults 18+ y * Confirmed clinical diagnosis of mild-to-moderate asthma, defined as: * A physician diagnosed asthma condition consistent with BTS/NICE/SIGN (2024) * Asthma managed at GINA (2024) step 1-3 therapy level, with stable maintenance treatment for ≥4 weeks prior to enrolment * No asthma exacerbation requiring systemic corticosteroids within the preceding 6-8 weeks (those with suspected Asthma will be invited to a familiarisation and eligibility session where they will have clinical investigations to assess for asthma and thus be included or excluded) * Ability to demonstrate acceptable and repeatable spirometry in accordance with ATS/ERS standards * Willing to refrain from antioxidant and anti-inflammatory supplementation (e.g. Omega-3, turmeric, NSAID supplements) for the duration of the study * Not consuming high dietary ASTX sources (e.g., frequent salmonid or crustacean intake), assessed at screening * non-smoking and non-vaping * Able and willing to take daily study capsules and attend all required visits * Able and willing to complete home monitoring, including peak flow, air-quality monitoring, and questionnaires * Able to provide written informed consent
Exclusion criteria
* Current smokers or vapers which is associated with chronic airway remodelling, reduce hyperresponsiveness to bronchodilators, and increased neutrophilic inflammation, which can obscure the true effects of asthma-target interventions * Respiratory tract infection within the preceding 4 weeks * Pregnant or lactating individuals * Presence of significant co-morbidities, including CVD or autoimmune or systemic inflammatory diseases * Renal or gastrointestinal disorders that may affect astaxanthin absorption and metabolism * Known allergy or hypersensitivity to ASTX or any components of the study supplement * History of current evidence of alcohol or substance abuse * Participation in another interventional drug or supplement study within the preceding 3 months * Use of medicines with a narrow therapeutic index where supplement interactions may pose risk (e.g., ciclosporin/tacrolimus, warfarin), assessed by investigator * Other significant chronic respiratory disease (e.g., COPD, bronchiectasis)
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Change in Forced Expiratory Volume in 1 Second (FEV1) | Measured at period-specific baseline and restablishment of baseline after washout period and end of each 4-week treatment period | FEV1 measured by spirometry using a calibrated Medisoft BodyBox system. Comparison is within-participant change after astaxanthin versus placebo. |
| Change in Fractional Exhaled Nitric Oxide (FeNO) | Measured at period-specific baseline and restablishment of baseline after washout period and end of each 4-week treatment period | FeNO measured in parts per billion using the NIOX VERO analyser. Comparison is within-participant change after astaxanthin versus placebo. |
| Change in Airway Hyperresponsiveness During Hypertonic Saline Challenge | Measured at period-specific baseline and end of each 4-week treatment period | Hypertonic saline challenge response quantified using the dose response slope |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Change in Impulse Oscillometry Resistance at 5 Hz (R5) | Baseline, end of phase 1, post washout and end of phase 2 | R5 measured during tidal breathing using the PulmoScan system |
| Change in Impulse Oscillometry Area of Reactance (AX) | Baseline, end of phase 1, post washout and end of phase 2 | AX measured using the PulmoScan system as an index of peripheral airway involvement. |
| Change in Asthma Control Questionnaire-6 (ACQ-6) Total Score | Weekly during the 11- to 12-week study period | Participant-reported asthma control measured using the ACQ-6. |
| Change in Asthma Quality of Life Questionnaire (AQLQ) Total Score | Participant-reported asthma-related quality of life measured using the AQLQ. | Every 2 weeks during the 11- to 12-week study period |
| Change in Peak Expiratory Flow Amplitude Percent Mean (PEF APM) | Twice daily during each treatment period and washout, up to 11 to 12 weeks | Diurnal variability in peak expiratory flow derived from home morning and evening PEF |
| Change in Sputum Eosinophil Percentage | Induced sputum cellular differential measured after hypertonic saline challenge. | Baseline, end of phase 1, post washout period and end of phase 2 |
| Change in Sputum Interleukin-8 (IL-8) Concentration | IL-8 measured in processed induced sputum. | Baseline, end of phase 1, post washout and end of phase 2 |
Countries
United Kingdom
Contacts
CONTACTAhmet Celen, PhD in Biomedical Science
CONTACTDr Lygeri Dimitriou
STUDY_DIRECTORLygeri Dimitriou
Middlesex University
Outcome results
None listed