Chronic Mountain Sickness, Systemic Vascular Function

Study Overview
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Brief Summary
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Diseases associated with chronic hypoxemia like chronic obstructive pulmonary disease (COPD) or emphysema, represent major medical and socio-economical problems and one of the leading cause of morbidity and mortality in the western countries. Recently, is has been shown that cardiovascular (CV) diseases contribute highly to the morbidity and mortality of these patients. Furthermore, increasing evidence suggest that systemic vascular dysfunction play a central role in the mediation of the increased CV risk in patients with COPD. However the underlying mechanisms of vascular dysfunction in these patients are incompletely understood. Chronic mountain sickness (CMS) is characterized by chronic hypoxemia related at least in part to hypoventilation; it affects relatively young adults, and may therefore allow to study the effects of chronic hypoxemia. The investigators therefore will assess systemic vascular function and test the hypothesis that increased oxidative stress is responsible for this dysfunction. Since polyglobulia is a hallmark of chronic hypoxemia and has been suggested to affect vascular function, the investigators will test the effects of hemodilution on vascular function. Then, the investigators will test the effects of acute oxygen application and 1 month antioxidative dietary supplement on vascular function. Preliminary data suggest that offspring of CMS patients may display pulmonary and systemic vascular dysfunction. Antioxidant administration is know to improve vascular function. We will test the acute effect of Vitamin C in this setting. Finally, since there is considerable inter-individual variability of pulmonary artery pressure among CMS patients and the presence of a patent foramen ovale (PFO)is increased in clinical conditions associated with pulmonary hypertension and hypoxemia, we will assess the prevalence of PFO in healthy high altitude dwellers and in CMS patients and its effects on pulmonary artery pressure at rest and during mild exercise.

Official Title
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Chronic Hypoxemia and Systemic Vascular Function

Conditions
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Mountain Sickness, Chronic

Intervention / Treatment
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* Dietary Supplement: Vitamin C and E
* Dietary Supplement: Placebo


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients with Chronic Mountain Sickness and their offspring Exclusion Criteria: Smoking Lung disease Arterial Hypertension

Ages Eligible for Study
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Minimum Age: 10 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Antioxidant<br> | Dietary Supplement: Vitamin C and E<br>* 1 month, 1g Vitamin C and 400 IE Vitamin E or Acute, 1g Vitamin C (in the offspring)<br>|
| Placebo Comparator: Control<br> | Dietary Supplement: Placebo<br>* 1 month Placebo<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Endothelial Function |  | 1 month | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Endothelial Function, Chronic Hypoxia, Oxidative Stress