Role of Free Radicals in the Pathophysiology of OSAS: A Narrative Review of A Double-Edged Sword

Obstructive sleep apnea (OSA) is a highly prevalent sleep-related breathing 1 disorder (SDB), primarily characterized by recurrent episodes of upper airway obstruction 2 during sleep. Individuals affected by OSA are at increased risk for a variety of adverse 3 health outcomes, particularly neurocognitive impairments and cardiovascular complica- 4 tions, highlighting the clinical significance of this condition. A defining feature of OSA is 5 intermittent hypoxemia, which contributes to the excessive production of reactive oxygen 6 species (ROS) and the subsequent development of oxidative stress. The primary objective 7 of this narrative review was to comprehensively investigate the intricate mechanisms of 8 oxidative stress and elucidate their complex interplay in the development and progression 9 of OSAS. Subsequently, we examined current literature to identify the most promising 10 biomarkers and pharmacological treatments related to OSA and oxidative stress. We found 11 that biomarkers of oxidative stress have shown potential in assessing disease severity and 12 tracking individual responses to therapy. However, none have yet been incorporated into 13 standard clinical practice. With regard to treatment, continuous positive airway pressure 14 (CPAP) remains the gold standard. Nevertheless, antioxidant therapy has emerged as 15 a potential adjunctive approach that may help address residual dysfunctions not fully 16 resolved by CPAP alone. Both the use of oxidative stress biomarkers and antioxidant-based 17 therapies require further validation through robust clinical studies before they can be 18 routinely implemented in clinical settings.