Sleep-disordered breathing and hypertension: past lessons, future directions

Area of Science:

• Cardiovascular Medicine
• Sleep Medicine
• Genetics

Background:

• Obstructive sleep apnea syndrome (OSAS) has been recognized as an independent risk factor for hypertension since the 1970s.
• Recent large-scale studies confirm the association between sleep-disordered breathing and hypertension.
• Understanding the underlying mechanisms is crucial for developing effective treatments.

Purpose of the Study:

• To investigate the mechanisms linking sleep-disordered breathing to hypertension.
• To explore the role of genetic factors and vascular endothelial dysfunction in this relationship.
• To assess the impact of continuous positive airway pressure (CPAP) on these mechanisms.

Main Methods:

• Analysis of genetic factors potentially influencing both blood pressure regulation and sleep-disordered breathing.
• Microneurography to assess sympathetic nervous system activity during sleep.
• Forearm plethysmography and dorsal hand vein techniques to evaluate endothelium-dependent and independent vasodilation during wakefulness.

Main Results:

• Sleep-disordered breathing is associated with abnormal sympathetic discharge during sleep.
• Impairment of endothelium-dependent vasodilation during wakefulness is frequently observed in individuals with sleep-disordered breathing.
• This endothelial dysfunction is more prevalent than impairment of endothelium-independent vasodilation and can be reversed by nasal CPAP therapy.

Conclusions:

• Genetic factors may contribute to both sleep-disordered breathing and hypertension.
• Impaired vascular endothelial function, specifically reduced endothelium-dependent vasodilation, is a key mechanism linking sleep-disordered breathing to hypertension.
• Nasal CPAP treatment shows potential for reversing this endothelial dysfunction, supporting its role in managing hypertension associated with sleep apnea.