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Anti-Oxidant Supplementation for the Prevention of Acute Mountain Sickness

NCT00664001 · Status: COMPLETED · Phase: PHASE3 · Type: INTERVENTIONAL · Enrollment: 83

Last updated 2008-04-22

No results posted yet for this study

Summary

Acute mountain sickness (AMS), high altitude pulmonary edema (HAPE), and high altitude cerebral edema (HACE) are complications of rapid ascent to high altitude. Several features suggest that raised intracranial pressure (ICP) may be an important factor in the pathogenesis of AMS. Magnetic resonance imaging of HACE patients has demonstrated that the oedema in HACE is of the vasogenic, rather that cytotoxic, type. Thus it is likely that cerebrovascular permeability has an important role in the development of AMS and HACE.

Reactive oxygen species (ROS) have been shown to alter the permeability of the blood-brain barrier in severe ischaemia, causing vasogenic cerebral oedema. Endogenous antioxidant systems may have some capacity to respond to oxidative stress in hypoxia. The plasma concentration of urate, a powerful endogenous antioxidant, rises on acute exposure to high altitude and may play a crucial antioxidant role in systemic hypoxia. This antioxidant prevents free-radical induced cerebral oedema in animal models.

There are numerous sources of ROS in hypoxia, including the mitochondrial electron transfer chain, haemoglobin (Hb) autoxidation and xanthine oxidase activity. There have been several reports of raised markers of oxidative stress in humans at moderate altitude (\<3000m).

Oral antioxidant supplementation with preparations containing vitamins C and E in humans at altitude has been shown to decrease breath pentanes (a marker of oxidative stress), and improve erythrocyte filterability. In a small randomised controlled trial, Bailey and Davies demonstrated a significant reduction in symptoms of AMS in subjects taking an oral antioxidant cocktail.

The antioxidants alpha-lipoic acid, vitamin C and vitamin E act synergistically to provide membrane protection from free radical damage, and may protect against hypoxia-induced vascular leakage. We hypothesised that this combination of antioxidants would reduce the severity of acute mountain sickness, and reduce pulmonary artery pressures, in healthy lowlanders acutely exposed to high altitude.

Conditions

  • Acute Mountain Sickness

Interventions

DIETARY_SUPPLEMENT

Anti-oxidant supplementation

Daily dose of 1g L-ascorbic acid, 400 IU of alpha-tocopherol acetate, and 600mg of alpha-lipoic acid in sealed capsules as anti-oxidant supplementation.

DIETARY_SUPPLEMENT

Matched placebo for anti-oxidant supplementation

Matched placebo for anti-oxidant supplementation

Sponsors & Collaborators

  • University of Edinburgh

    collaborator OTHER

  • Altitude Physiology Expeditions

    lead OTHER

Principal Investigators

  • Kenneth Baillie · Apex Bioscience

Study Design

Allocation
RANDOMIZED
Purpose
PREVENTION
Masking
QUADRUPLE
Model
PARALLEL

Eligibility

Min Age
18 Years
Max Age
65 Years
Sex
ALL
Healthy Volunteers
Yes

Timeline & Regulatory

Start
2003-03-31
Primary Completion
2003-08-31
Completion
2003-12-31

Countries

  • United Kingdom

Study Locations

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Read the full study record

This page highlights key information. For complete eligibility criteria, study locations, investigator contacts, and the full protocol, visit the original record on ClinicalTrials.gov.

View NCT00664001 on ClinicalTrials.gov