NCT00952302

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

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

• Status: Completed
• Phase: N/A
• Study type: Interventional
• Enrollment: 33 (actual)
• Sponsor: University of Oxford · Academic / Other
• Sex: Male
• Age: 18 Years – 60 Years
• Healthy volunteers: Accepted

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.

Detailed 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.

Conditions

• Pulmonary Hypertension
• Mountain Sickness

Interventions

Type	Name	Description
DRUG	Iron sucrose	Single intravenous infusion of iron 200 mg
DRUG	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.
DRUG	Normal saline	Two intravenous infusions of normal 0.9% saline 100 mls (as placebo), separated by one day.

Timeline

• Start date: 2008-10-01
• Primary completion: 2008-11-01
• Completion: 2008-11-01
• First posted: 2009-08-06
• Last updated: 2009-08-06

Locations

1 site across 1 country: Peru