Study of the Effects of Iron Levels on the Lungs at High Altitude

Pulmonary Hypertension Clinical Trial

Official title:

Physiology Study Investigating the Effects of Supplementation and Depletion of Iron on Hypoxia-related Pulmonary Hypertension

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT00952302
• Other study ID #: Oxford-Peru-2008
• Status: Completed
• Phase: N/A
• First received: August 4, 2009
• Last updated: August 4, 2009
• Start date: October 2008
• Est. completion date: November 2008

Study information

• Verified date: August 2009
• Source: University of Oxford
• Contact: n/a
• Is FDA regulated: No
• Health authority: United Kingdom: Research Ethics Committee
• Study type: Interventional

Clinical Trial Summary

The study hypothesis is that body iron levels are important in determining the increase in lung blood pressure that occurs in response to low oxygen levels. The purpose of this study is to determine whether this is true at high altitude, where oxygen levels are low.

Description:

Pulmonary hypertensive disorders frequently complicate hypoxic lung disease and worsen patient survival. Hypoxia-induced pulmonary hypertension is also a major cause of morbidity at high altitude. Hypoxia causes pulmonary hypertension through hypoxic pulmonary vasoconstriction and vascular remodelling. These processes are thought to be regulated at least in part by the hypoxia-inducible factor (HIF) family of transcription factors, which coordinate intracellular responses to hypoxia throughout the body.

HIF is regulated through a cellular degradation process that requires iron as an obligate cofactor. In cultured cells HIF degradation is inhibited by reduction in iron (by chelation with desferrioxamine) and potentiated by iron supplementation. In humans, we have recently shown that, in laboratory experiments lasting 8 hours, acute iron supplementation blunts the pulmonary vascular response to hypoxia, while acute iron chelation with desferrioxamine enhances the response.

This suggests that iron may also affect the pulmonary artery pressure response to hypoxia over longer time periods. The purpose of this study is to investigate this link between iron and the pulmonary artery pressure response to hypoxia, through a study conducted at high altitude allowing concurrent exposure of larger numbers of participants to environmental hypoxia. We wish to explore the extent and the time-course of the effect of iron on pulmonary artery pressure. Cerro de Pascu (4,340 m) in Peru provides the unique ability to make rapid transitions from sea level to high altitude (6-8 hours by road), together with the requisite research facilities. Also, one part of this study involves recruitment of patients with chronic mountain sickness, of whom there are many living in Cerro de Pasco.

Recruitment information / eligibility

• Status: Completed
• Enrollment: 33
• Est. completion date: November 2008
• Est. primary completion date: November 2008
• Accepts healthy volunteers: Accepts Healthy Volunteers
• Gender: Male
• Age group: 18 Years to 60 Years

Eligibility

SLR ARM

Inclusion Criteria:

• sea level natives of lowland ancestry

• generally in good health

• detectable tricuspid regurgitation on echocardiography

Exclusion Criteria:

• any significant medical problem

• known susceptibility to high altitude pulmonary or cerebral oedema

• taking medications or iron supplements

CMS ARM

Inclusion Criteria:

• diagnosis of chronic mountain sickness

• no recent venesection therapy (within 1 year)

• detectable tricuspid regurgitation on echocardiography

Exclusion Criteria:

• any other significant medical problem

Study Design

Allocation: Randomized, Endpoint Classification: Efficacy Study, Intervention Model: Crossover Assignment, Masking: Double Blind (Subject, Caregiver, Investigator, Outcomes Assessor), Primary Purpose: Basic Science

Related Conditions & MeSH terms

• Altitude Sickness
• Hypertension
• Hypertension, Pulmonary
• Mountain Sickness
• Pulmonary Hypertension

Intervention

Drug:
• Iron sucrose
Single intravenous infusion of iron 200 mg
• Normal saline
Single intravenous infusion of normal 0.9% saline 100 mls (as placebo)

Procedure:
• Venesection
Isolvolaemic venesection of total 2 litres of blood - 500 mls each day for 4 days, replaced with normal saline.

Drug:
• Iron sucrose
Two intravenous infusions, each of 200 mg of iron, separated by one day.
• Normal saline
Two intravenous infusions of normal 0.9% saline 100 mls (as placebo), separated by one day.

Locations

Country	Name	City	State
Peru	Universidad Peruana Cayetano Heredia	Lima

Sponsors (2)

Lead Sponsor	Collaborator
University of Oxford	Universidad Peruana Cayetano Heredia

Country where clinical trial is conducted

Peru, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	Change in pulmonary artery systolic pressure		One week (SLR arm) and one month (CMS arm)	No