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Pik Lenin High Altitude Research Expedition 2009 (PLHARE)

This study has been completed.
Kantonsspital Aarau
Lotteriefonds des Kantons Aarau
Schweizer Gesellschaft für Gebirgsmedizin
University of Bern
Information provided by (Responsible Party):
University Hospital Inselspital, Berne Identifier:
First received: March 28, 2012
Last updated: April 3, 2012
Last verified: April 2012
Exposure to hypobaric hypoxia demands maximum effort of the body and can lead to high altitude illnesses. Recently, there is rising interest on coagulation activation during trekking and mountaineering in higher regions and on development of oxidative stress due to hypoxia. 30 volunteers have been examined during an high altitude research expedition to the 7134m high mount Pik Lenin in Kyrgyzstan to investigate mechanisms of coagulation activation and effects of antioxidant supplements on oxidative stress.

Condition Intervention
Oxidative Stress
Cell-derived Microparticles
Dietary Supplement: antioxidant supplements
Dietary Supplement: Placebo

Study Type: Interventional
Study Design: Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double Blind (Participant, Care Provider, Investigator, Outcomes Assessor)
Primary Purpose: Supportive Care
Official Title: Pik Lenin High Altitude Research Expedition 2009, a Follow-up Project of the Muztagh Ata High Altitude Research Expedition 2005

Resource links provided by NLM:

Further study details as provided by University Hospital Inselspital, Berne:

Primary Outcome Measures:
  • Change from baseline in oxidative stress [ Time Frame: during expedition, up to 22 days ]

Secondary Outcome Measures:
  • Change from baseline in coagulation activation [ Time Frame: during expedition, up to 22 days ]
  • Change from baseline in acute mountain sickness score [ Time Frame: during expedition, up to 22 days ]
  • Change from baseline in oxygen saturation in blood [ Time Frame: during expedition, up to 22 days ]

Enrollment: 30
Study Start Date: April 2009
Study Completion Date: August 2009
Primary Completion Date: August 2009 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Active Comparator: antioxidant supplements
800 I.E. Vitamin E, 1000mg Vitamin C, 200000 I.E. Vitamin A, 600mg Acetylcystein.
Dietary Supplement: antioxidant supplements
Intake of 6 tablets daily containing: 800 I.E. Vitamin E, 1000mg Vitamin C, 200000 I.E. Vitamin A, 600mg Acetylcystein.
Placebo Comparator: Placebo
identically appearing placebo
Dietary Supplement: Placebo
Intake of 6 identically appearing tablets daily containing placebo

Detailed Description:

Reactions to acute exposure to high altitude and the process of acclimatization has been of scientific interest since many years. High altitude illnesses are specified by three different entities: acute mountain sickness (AMS), high altitude pulmonary edema (HAPE) and high altitude cerebral edema (HACE). Prevalence of AMS is known to be between 10 to 20% for altitudes between 4000 and 5000m, increasing significantly in higher altitude. The prevalence depends on the ascent rate, individual susceptibility and physical exhaustion.

Although mechanisms leading to high altitude illnesses are not yet completely clear some progress has been made. It is well accepted that excessive pulmonary hypertension may lead to HAPE. Furthermore, there is rising evidence about endothelial dysfunction being involved in disease progression. Some cellular and molecular mechanisms of acute (hypobaric) hypoxia, possibly leading to endothelial dysfunction, have been studied in a few experimental and field settings. Paradoxical increase in systemic oxidative stress is seen under hypoxic conditions, such as high altitude stay. Reactive oxygen species (ROS) could be demonstrated in many endothelial disorders and capillary leakage syndromes such as septicaemia, myocardial infarct and stroke. Furthermore, coagulation activation might result from endothelial dysfunction but also amplify endothelial interruption. Still, most of our knowledge concerning effects of hypoxia in general but also concerning oxidative stress is from in vitro studies (e.g. cancer cells).

In the context of a high altitude expedition human subjects can safely be submitted to prolonged hypoxia to explore generation of ROS and extent of procoagulatory state.


The purpose of our study is to confirm excessive oxidative stress found in our previous study in 2005 and to investigate whether oxidative stress during high altitude exposure can be modified by dietary supplementations of specific antioxidants. Moreover, we like to study mechanisms of coagulation activation by assessing extent of thrombocytic and endothelial microparticles.


After approval of the study by the regional ethics committee, written informed consent has been obtained from 30 healthy volunteers (low land residents with mountaineering experience, age 18-65 years). After baseline testing, double-blind randomization into 2 groups of 15 persons took place. One group received oral medication with vitamin E, vitamin C, vitamin A and acetylcystein daily, while the other group was provided with an identical appearing placebo preparation. Substitution started 2 month before the expedition. After examination at "ground 0" in Zurich (409m) all members underwent testing in Base Camp (3550m), twice in advanced Base Camp (4550m), in Camp 1 (5430m), and in Camp 2 (6265m). Beside blood sampling, clinical examinations were performed. Metabolomics, a mass-spectrometry based analysis, for measurement of oxidative stress, will be performed. In a subgroup microparticles will be detected by annexin V based ELISA and by flow cytometry using specific antibodies.


Ages Eligible for Study:   18 Years to 65 Years   (Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes

Inclusion Criteria:

  • good health status
  • age 18-65
  • mountaineering experience

Exclusion Criteria:

  • any metabolic disorders
  • regular drug intake
  • any disease of the lungs
  • any disease of the heart
  • any renal abnormality
  Contacts and Locations
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Please refer to this study by its identifier: NCT01571687

Center of Laboratory Medicine Cantonal Hospital Aarau and University of Bern
Aarau, Switzerland, 5001
Sponsors and Collaborators
University Hospital Inselspital, Berne
Kantonsspital Aarau
Lotteriefonds des Kantons Aarau
Schweizer Gesellschaft für Gebirgsmedizin
University of Bern
Study Chair: Andreas R Huber, Prof. Dr. med. Center of Laboratory Medicine Cantonal Hospital Aarau and University of Bern
Principal Investigator: Jacqueline Pichler Hefti, Dr. med. Division of Pneumology, Inselspital Bern, Universityhospital Bern
  More Information

Responsible Party: University Hospital Inselspital, Berne Identifier: NCT01571687     History of Changes
Other Study ID Numbers: 2008/071
07.09.34 ( Other Identifier: University Hospital Berne )
Study First Received: March 28, 2012
Last Updated: April 3, 2012

Keywords provided by University Hospital Inselspital, Berne:
blood coagulation disorders
cell-derived microparticles
oxidative stress

Additional relevant MeSH terms:
Growth Substances
Physiological Effects of Drugs
Molecular Mechanisms of Pharmacological Action
Protective Agents processed this record on May 25, 2017