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J Appl Physiol (1985). 2015 Nov 15;119(10):1152-6. doi: 10.1152/japplphysiol.00162.2015. Epub 2015 May 7.

Neural regulation of hypoxia-inducible factors and redox state drives the pathogenesis of hypertension in a rodent model of sleep apnea.

Author information

1
Institute for Cell Engineering and McKusick-Nathans Institute of Genetic Medicine, Departments of Pediatrics, Medicine, Oncology, Radiation Oncology, and Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, Maryland; and gsemenza@jhmi.edu.
2
Institute for Integrative Physiology and Center for Systems Biology of O2 Sensing, Biological Sciences Division, University of Chicago, Chicago, Illinois.

Abstract

Obstructive sleep apnea (OSA) is one of the most common causes of hypertension in western societies. OSA causes chronic intermittent hypoxia (CIH) in specialized O2-sensing glomus cells of the carotid body. CIH generates increased reactive oxygen species (ROS) that trigger a feedforward mechanism in which increased intracellular calcium levels ([Ca(2+)]i) trigger increased HIF-1α synthesis and increased HIF-2α degradation. As a result, the normal homeostatic balance between HIF-1α-dependent prooxidant and HIF-2α-dependent antioxidant enzymes is disrupted, leading to further increases in ROS. Carotid body sensory nerves project to the nucleus tractus solitarii, from which the information is relayed via interneurons to the rostral ventrolateral medulla in the brain stem, which sends sympathetic neurons to the adrenal medulla to stimulate the release of epinephrine and norepinephrine, catecholamines that increase blood pressure. At each synapse, neurotransmitters trigger increased [Ca(2+)]i, HIF-1α:HIF-2α, and Nox2:Sod2 activity that generates increased ROS levels. These responses are not observed in other regions of the brain stem that do not receive input from the carotid body or signal to the sympathetic nervous system. Thus sympathetic nervous system homeostasis is dependent on a balance between HIF-1α and HIF-2α, disruption of which results in hypertension in OSA patients.

KEYWORDS:

NADPH oxidase; hypoxia-inducible factors; oxidative stress; superoxide dismutase

PMID:
25953833
PMCID:
PMC4816415
DOI:
10.1152/japplphysiol.00162.2015
[Indexed for MEDLINE]
Free PMC Article

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