Insulin resistance is associated with Sfrp5 in obstructive sleep apnea

Pathophysiological mechanisms and therapeutic approaches in obstructive sleep apnea syndrome

Obstructive sleep apnea syndrome (OSAS) is a common breathing disorder in sleep in which the airways narrow or collapse during sleep, causing obstructive sleep apnea. The prevalence of OSAS continues to rise worldwide, particularly in middle-aged and elderly individuals. The mechanism of upper airway collapse is incompletely understood but is associated with several factors, including obesity, craniofacial changes, altered muscle function in the upper airway, pharyngeal neuropathy, and fluid shifts to the neck. The main characteristics of OSAS are recurrent pauses in respiration, which lead to intermittent hypoxia (IH) and hypercapnia, accompanied by blood oxygen desaturation and arousal during sleep, which sharply increases the risk of several diseases. This paper first briefly describes the epidemiology, incidence, and pathophysiological mechanisms of OSAS. Next, the alterations in relevant signaling pathways induced by IH are systematically reviewed and discussed. For example, IH can induce gut microbiota (GM) dysbiosis, impair the intestinal barrier, and alter intestinal metabolites. These mechanisms ultimately lead to secondary oxidative stress, systemic inflammation, and sympathetic activation. We then summarize the effects of IH on disease pathogenesis, including cardiocerebrovascular disorders, neurological disorders, metabolic diseases, cancer, reproductive disorders, and COVID-19. Finally, different therapeutic strategies for OSAS caused by different causes are proposed. Multidisciplinary approaches and shared decision-making are necessary for the successful treatment of OSAS in the future, but more randomized controlled trials are needed for further evaluation to define what treatments are best for specific OSAS patients.

Sestrin2 in hypoxia and hypoxia-related diseases

Objectives: Sestrin2 is a stress-inducible protein and play an important role in adapting stress states of cells. This article reviewed the role of Sestrin2 in hypoxia and hypoxia-related diseases to provide new perspectives for future research and new therapeutic targets for hypoxia-related diseases.

Methods: A review was conducted through an electronic search of PubMed and Medline databases. Keywords included Sestrin2, ROS, hypoxia, and hypoxia-related disease. Articles from 2008 to 2021 were mostly included and older ones were not excluded.

Results: Sestrin2 is upregulated under various stress conditions, especially hypoxia. Under hypoxic condition, Sestrin2 plays a protective role by reducing the generation of ROS through various pathways, such as adenosine monophosphatea-ctivated protein kinase (AMPK) / mammalian target of rapamycin (mTOR) pathway and nuclear factor-E2-related factor2 (Nrf2) pathway. In addition, Sestrin2 is involved in various hypoxia-related diseases, such as cerebral hypoxic disease, myocardial hypoxic disease, hypoxia-related respiratory disease, and diabetes.

Discussion: Sestrin2 is involved in various hypoxia-related diseases and maybe a therapeutic target. Furthermore, most studies focus on cerebral and myocardial ischemia reperfusion. More researches on hypoxia-related respiratory diseases, kidney injury, and diabetes are needed in future.

Association of Adipocytokines With Carotid Intima Media Thickness and Arterial Stiffness in Obstructive Sleep Apnea Patients

Objective: Obstructive sleep apnea (OSA) results in increased carotid intima-media thickness (IMT) and arterial stiffness; however, the association between adipocytokines and IMT/arterial stiffness in OSA patients is unclear. Methods: We enrolled 95 normal weight and overweight, not obese, participants from May 2018 to December 2018 in this study. All subjects underwent a carotid artery ultrasound examination and polysomnography. Blood samples were used to determine serum chemerin, adiponectin, SFRP5, and apelin levels. Correlations between two quantitative variables were assessed using the Pearson or Spearman coefficient. Stepwise models of multiple linear regression analysis were performed to assess the independent relationships. Result: IMT in OSA patients was significantly higher than in the non-snorers. There were significant differences in the arterial stiffness parameters such as distensibility coefficient (DC), compliance coefficient (CC), and pulse wave velocity (PWV). SFRP5 level was lower in OSA patients than in non-snorers. Adiponectin correlated with CC, DC, and PWV among OSA patients; however, the relationship disappeared after a multivariable adjustment. Age was independently associated with all quantitative IMT and stiffness indices. AHI and minimum oxygen saturation (Mini SaO₂) were independently related to arterial stiffness. Conclusion: The quantitative IMT and carotid arterial elasticity were significantly worse among OSA patients. Age was the main independent factor correlated with quantitative IMT and arterial stiffness, and AHI and mini SaO₂ were associated factors. There were no relationships between aforementioned adipocytokines and quantitative IMT/carotid arterial stiffness.