Effects of Iron on Exercise Capacity During Hypoxia

Effects of Intravenous Iron Supplementation on Exercise Capacity During Sustained Alveolar Hypoxia in Healthy Humans.

During alveolar hypoxia, for example at high altitude or in patients with respiratory disease, there is evidence to suggest that hypoxia-induced pulmonary hypertension might limit exercise performance. Intravenous iron supplementation has recently been shown to reverse pulmonary hypertension in healthy humans at high altitude, and to prevent pulmonary hypertension in volunteers exposed to hypoxia at sea level. The investigators hypothesized that intravenous iron supplementation would enhance exercise capacity during alveolar hypoxia.

Study Overview

• Status: Completed
• Conditions: Healthy Volunteers
• Intervention / Treatment: Drug: Iron sucrose.; Drug: Normal saline

• Study Type: Interventional
• Enrollment (Actual): 12
• Phase: Phase 1

Contacts and Locations

Study Locations

• United Kingdom
  • Oxford, United Kingdom, OX1 3PT
    • Department of Physiology, Anatomy & Genetics, University of Oxford

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 60 years (Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• Age between 18 and 60 years
• Sea level natives with no recent exposure to high altitude
• Baseline iron indices within the normal range
• Detectable tricuspid regurgitation on echocardiography

Exclusion Criteria:

• Significant cardiorespiratory disease
• Known susceptibility to high altitude-related illness
• Taking medications or iron supplementation
• Pregnancy

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Non-Randomized
• Interventional Model: Crossover Assignment
• Masking: Double

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Intravenous iron sucrose; Infusion of 200 mg iron sucrose (Venofer) in 100 ml normal (0.9%) saline.	Drug: Iron sucrose.; Volunteers will receive an intravenous infusion of 200 mg iron sucrose, before exposure to 8 hours of alveolar hypoxia. At the end of the exposure, pulmonary artery systolic pressure will be measured and volunteers will undertake an exercise test while breathing hypoxic gas.; Other Names: Iron sucrose = Venofer
Placebo Comparator: Intravenous normal saline; Infusion of 100 ml normal (0.9%) saline.	Drug: Normal saline; Volunteers will receive an intravenous infusion of 100 ml normal saline, before exposure to 8 hours of alveolar hypoxia. At the end of the exposure, pulmonary artery systolic pressure will be measured and volunteers will undertake an exercise test while breathing hypoxic gas.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Maximal exercise capacity during hypoxia, assessed by maximal oxygen consumption.	Volunteers will receive either intravenous iron or saline placebo, before exposure to 8 hours of alveolar hypoxia. They will then undergo an exercise test while breathing an hypoxic gas mixture. The primary outcome measure will be exercise capacity as determined by maximal oxygen consumption during this test. Volunteers will receive both interventions, via a crossover design. Due to uncertainty about the duration of action of iron at a cellular level, all volunteers will receive saline infusion on the first study day, and iron sucrose infusion on a second study day, at least one week later.	After 8-h exposure to alveolar hypoxia.

Secondary Outcome Measures

Outcome Measure	Time Frame
Maximal exercise capacity, assessed by peak power output.	After 8-h exposure to alveolar hypoxia.
Pulmonary artery systolic pressure.	After 8-h exposure to alveolar hypoxia.
Blood levels of oxygen-regulated proteins.	After 8-h exposure to alveolar hypoxia

Collaborators and Investigators

• Sponsor: University of Oxford
• Investigators: Principal Investigator: Nick P Talbot, DPhil MRCP, University of Oxford

Study record dates

Study Major Dates

• Study Start: November 1, 2010
• Primary Completion (Actual): January 1, 2015
• Study Completion (Actual): April 1, 2015

Study Registration Dates

• First Submitted: December 21, 2010
• First Submitted That Met QC Criteria: December 21, 2010
• First Posted (Estimate): December 22, 2010

Study Record Updates

• Last Update Posted (Estimate): July 29, 2015
• Last Update Submitted That Met QC Criteria: July 27, 2015
• Last Verified: July 1, 2015

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Signs and Symptoms, Respiratory; Hypoxia; Physiological Effects of Drugs; Trace Elements; Micronutrients; Hematinics; Iron; Ferric Oxide, Saccharated
• Other Study ID Numbers: OHSRC-986