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Vascular consequences of intermittent hypoxia
1Department of Orthopedics and Rehabilitation, University of Wisconsin-Madison, Madison, Wisconsin, USA. morgan@surgery.wisc.edu
Advances in Experimental Medicine and Biology
|February 14, 2008
Summary
Obstructive sleep apnea (OSA) causes sustained high blood pressure through intermittent hypoxia. This involves the sympathetic nervous system, carotid chemoreceptors, and renin-angiotensin system, leading to vascular dysfunction.
Area of Science:
- Cardiovascular Physiology
- Sleep Medicine
- Renal Physiology
Background:
- Obstructive sleep apnea (OSA) is linked to sustained hypertension.
- Nocturnal intermittent hypoxia in OSA elevates arterial pressure throughout the day.
- This hypertensive effect is mediated by the sympathetic nervous system and carotid chemoreceptor reflex.
Purpose of the Study:
- To investigate the mechanisms underlying intermittent hypoxia-induced hypertension in OSA.
- To explore the role of the renin-angiotensin system and vascular endothelium in OSA-related hypertension.
- To identify potential therapeutic targets for cardiovascular sequelae of OSA.
Main Methods:
- Utilized animal models of OSA to study hypertensive effects.
- Investigated the impact of renal nerve denervation and angiotensin II receptor blockade.
- Assessed vascular endothelial function, nitric oxide metabolites, superoxide production, and inflammatory cytokines.
Main Results:
- The hypertensive effect of intermittent hypoxia requires intact sympathetic nervous system and carotid chemoreceptor reflex.
- The renin-angiotensin system significantly contributes to OSA-induced hypertension.
- Vascular endothelium is functionally impaired in OSA, evidenced by reduced nitric oxide and increased oxidant stress and inflammation.
Conclusions:
- Oxidant stress and inflammation are key mediators of intermittent hypoxia-induced vascular dysfunction in OSA.
- Understanding these mechanisms can lead to strategies to prevent or reverse OSA-related cardiovascular damage.
- Research has implications for hypertension, atherosclerosis, and other cardiovascular issues associated with OSA.
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