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

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Brief Title

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

Official Title

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

Brief 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.
    


Study Type

Interventional


Primary Outcome

Change in pulmonary artery systolic pressure


Condition

Pulmonary Hypertension

Intervention

Iron sucrose

Study Arms / Comparison Groups

 CMS - placebo first
Description:  Patients with chronic mountain sickness (CMS) who are venesected and studied for several weeks. In the final crossover period of the study, patients receive a placebo (saline) infusion first followed by iron infusion.

Publications

* Includes publications given by the data provider as well as publications identified by National Clinical Trials Identifier (NCT ID) in Medline.

Recruitment Information


Recruitment Status

Drug

Estimated Enrollment

33

Start Date

October 2008

Completion Date

November 2008

Primary Completion Date

November 2008

Eligibility Criteria

        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
      

Gender

Male

Ages

18 Years - 60 Years

Accepts Healthy Volunteers

Accepts Healthy Volunteers

Contacts

Peter A Robbins, BMBCh DPhil, , 

Location Countries

Peru

Location Countries

Peru

Administrative Informations


NCT ID

NCT00952302

Organization ID

Oxford-Peru-2008



Study Sponsor

University of Oxford

Collaborators

 Universidad Peruana Cayetano Heredia

Study Sponsor

Peter A Robbins, BMBCh DPhil, Principal Investigator, University of Oxford


Verification Date

August 2009