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Sustained systemic arterial hypertension induced by extended hypobaric hypoxia
1Department of Medicine, University of California, Irvine, USA.
Kidney International
|May 1, 1996
Summary
Prolonged exposure to low oxygen (hypobaric hypoxia) in rats caused lasting high blood pressure, independent of red blood cell levels. Endogenous erythropoietin (EPO) did not appear to cause this hypertension.
Area of Science:
- Physiology
- Cardiovascular Science
- Environmental Medicine
Background:
- Recombinant erythropoietin (EPO) therapy can increase blood pressure.
- The effect of stimulating endogenous EPO production on blood pressure is not well understood.
Purpose of the Study:
- To investigate if prolonged stimulation of endogenous EPO production via hypobaric hypoxia causes sustained hypertension.
- To determine if this hypertension is dependent on elevated hematocrit.
Main Methods:
- Male Sprague-Dawley rats were exposed to hypobaric hypoxia (390 mm Hg) for 24 days.
- Blood pressure, plasma EPO, hematocrit, erythrocyte mass, and blood volume were monitored.
- Experiments were repeated with hematocrit controlled via phlebotomy to isolate hypoxia effects.
Main Results:
- Hypobaric hypoxia induced a sustained increase in blood pressure that persisted after normoxia.
- Hypertension occurred independently of hematocrit levels.
- Endogenous EPO levels returned to baseline, suggesting it's not the cause of sustained hypertension.
Conclusions:
- Prolonged hypobaric hypoxia induces persistent, hematocrit-independent systemic hypertension.
- Endogenous EPO does not appear to be the primary driver of this hypertension.
- This rat model offers a platform for studying acquired hypertension mechanisms and treatments.