Effects of short-term mild hypercapnia during head-down tilt on intracranial pressure and ocular structures in healthy human subjects.
Steven S Laurie, Gianmarco Vizzeri, Giovanni Taibbi...
https://pubmed.ncbi.nlm.nih.gov/28611153/Actively Recruiting
Led by National Aeronautics and Space Administration (NASA) · Updated on 2025-05-22
16
Participants Needed
1
Research Sites
274 weeks
Total Duration
Researchers are evaluating a daily nutraceutical supplement containing bioactive B vitamins to reduce optic disc edema in astronauts during long-duration space missions. This study focuses on optimizing the one-carbon metabolic pathway to improve enzyme function, enhance blood vessel health, strengthen eye tissue elasticity, and reduce retinal thickness changes. The investigation aims to better understand causes of optic disc edema and the effects of this nutritional countermeasure compared to astronauts who did not use supplements. Participants will take a vitamin B-complex supplement before, during, and after a 6 to 12 month spaceflight on the International Space Station. This supplement includes 5-methyltetrahydrofolate, riboflavin 5 phosphate, pyridoxal phosphate, and methylcobalamin. Blood samples are collected multiple times before, during, and after flight to assess vitamin levels, biochemistry, and genetic markers. Eye scans using optical coherence tomography and blood flow measurements will monitor ocular and vascular health. Throughout the study, participants will undergo various tests including blood draws, skin scans for advanced glycation end products, and fingertip temperature assessments to evaluate vascular function. Dietary intake, exercise logs, and medication use will be reviewed. The main outcome is measuring optic disc edema over six months, along with secondary measures of endothelial function, vitamin statuses, oxidative stress markers, and other biochemical indicators. The study lasts throughout the flight and follow-up periods to monitor ongoing effects.
CONDITIONS
B-Complex: A Nutraceutical SANS Countermeasure
S
Sara Zwart, PhD
E
Eden Fields
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National Aeronautics and Space Administration (NASA)
Lead Sponsor
Mayo Clinic
Collaborating Sponsor
This table compares participation in this trial with other options available for this condition. The information is drawn from published research and the trial’s study details and is provided for educational purposes only.
| Factors | Vitamin B-Complex Supplement (Trial) | Current Standard Care (No Targeted B-Complex) |
|---|---|---|
| What is it? | A clinical trial supplementing astronauts on long missions with a vitamin B-complex formula that includes 5-methyltetrahydrofolate, riboflavin 5 phosphate, pyridoxal phosphate, and methylcobalamin, aimed at preventing optic disc edema and endothelial dysfunction during spaceflight. | Current practice for astronauts at risk of SANS and vascular dysfunction involves routine health monitoring and supportive measures but does not include targeted B-vitamin supplementation for prevention. Management is largely observational, with responsive care if symptoms develop. |
| Role in study or care | Investigational intervention given to all enrolled astronauts during their missions to evaluate whether supplementation can prevent optic disc edema and vascular changes associated with spaceflight. | Serves as the standard of care, where astronauts are closely monitored for ocular and vascular health changes during missions but do not routinely receive a preventative B-complex supplement. |
| Primary purpose or use | To test if daily B-complex supplementation reduces the incidence or severity of optic disc swelling and vascular dysfunction in astronauts in microgravity. | To monitor for early signs of neuro-ocular and vascular health issues so that intervention can occur if symptoms appear. No preventative supplement is standard. |
| How is it given or performed? | Vitamin B-complex is orally administered daily throughout the astronaut’s mission on the International Space Station. | Routine health monitoring includes periodic eye and vascular assessments but does not include preventative B-vitamin supplementation. Support is provided as needed if changes are detected. |
| Evidence status or maturity | Efficacy and safety have not been established; results are pending as this is an early-phase trial. | Current-care observational monitoring is supported by published consensus as the standard method, but no established intervention is proven to prevent SANS. Some evidence suggests B-vitamin status may relate to risk; more research is needed. |
| Important limitations or knowledge gaps | Pilot study in an extremely small, highly selected population. Uncertainties include generalizability, optimal supplementation regimen, and true effect size. Outcomes limited by sample size, absence of control group, and difficulty distinguishing supplement effect from natural variation. | Current standard reflects a lack of established countermeasure for SANS; risk factors are incompletely understood and supportive care does not prevent onset. No proven intervention for prevention; monitoring can only identify changes after onset. |
Disclaimer: This comparison is created with the help of artificial intelligence(AI) and may contain errors or missing information. It is not medical advice and does not mean one option is better or safer than another. Clinical trials are still being studied, and joining a trial is your choice. Please consult your healthcare professional before making any decisions.
You may qualify if you...
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Duration - 2 to 4 weeks
Participants are screened for eligibility to participate in the trial.
Duration - 6 to 12 months
Participants take a vitamin B-complex supplement before, during, and after their spaceflight mission on the International Space Station lasting 6 to 12 months.
Visits for blood sample collection and assessments occur approximately 180 days and 45 days before flight, on flight day 90, 30 days before landing, 0 to 2 days after return to Earth, and 30 days after landing.
Study Type
INTERVENTIONAL
Masking
NONE
Allocation
NA
Model
SINGLE_GROUP
Primary Purpose
PREVENTION
Number of Arms
1
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Steven S Laurie, Gianmarco Vizzeri, Giovanni Taibbi...
https://pubmed.ncbi.nlm.nih.gov/28611153/Heather R McGregor, Jessica K Lee, Edwin R Mulder...
https://pubmed.ncbi.nlm.nih.gov/34105833/Sara R Zwart, Steven S Laurie, John J Chen...
https://pubmed.ncbi.nlm.nih.gov/31415055/Scott M Smith, Sara R Zwart
https://pubmed.ncbi.nlm.nih.gov/30169456/Sara R Zwart, Charles R Gibson, Jesse F Gregory...
https://pubmed.ncbi.nlm.nih.gov/28546443/National Aeronautics and Space Administration (NASA)
Lead Sponsor
Mayo Clinic
Collaborating Sponsor