Which place of pharmacological approaches beyond continuous positive airway pressure to treat vascular disease related to obstructive sleep apnea?

Effects of obstructive sleep apnea on myocardial injury and dysfunction: a review focused on the molecular mechanisms of intermittent hypoxia

Obstructive sleep apnea (OSA) is characterized by intermittent hypoxia (IH) and is strongly associated with adverse cardiovascular outcomes. Myocardial injury and dysfunction have been commonly observed in clinical practice, particularly in patients with severe OSA. However, the underlying mechanisms remain obscure. In this review, we summarized the molecular mechanisms by which IH impact on myocardial injury and dysfunction. In brief, IH-induced cardiomyocyte death proceeds through the regulation of multiple biological processes, including differentially expressed transcription factors, alternative epigenetic programs, and altered post-translational modification. Besides cell death, various cardiomyocyte injuries, such as endoplasmic reticulum stress, occurs with IH. In addition to the direct effects on cardiomyocytes, IH has been found to deteriorate myocardial blood and energy supply by affecting the microvascular structure and disrupting glucose and lipid metabolism. For better diagnosis and treatment of OSA, further studies on the molecular mechanisms of IH-induced myocardial injury and dysfunction are essential.

X-Ray Cephalometric Analysis of the Effects of Angle Class II and III Malocclusion on the Upper Airway Width and Hyoid Position between Parents and Children of Uygur Nationality

Objective

The objective of this paper is to analyze the effect of angle class II and III malocclusion on the sagittal diameter of the upper airway between parents and children of Uygur nationality and to compare the degree of influence.

Methods

29 Uygur adolescents with malocclusion and their fathers (mothers) were selected as our subjects via X-ray cephalometric radiograph to analyze the difference between the upper airway sagittal dimension and normal occlusion and compare the influence of malocclusion on the upper airway between parents and children.

Results

Compared with normal group, the vertical distance from the hyoid point to orbital-ear plane (H-FH) and vertical distance from hyoid point to the mandibular plane (H-MP) in angle class II malocclusion elevated signally, while the vertical distance from hyoid point to anterior cervical plane (H-VL), PNS-UPW, H-FH, and H-MP decreased significantly; compared with normal group: the distance between the posterior nasal spine and the upper pharynx wall (PNS-UPW), H-FH, and H-MP in angle class III malocclusion visually reduced, while PAS, and horizontal distance from the hyoid point and center point of sella turcica to orbital-ear foot (H-S), increased markedly. The impact of class II malocclusion on parents' U-MPM was greater than their children.

Conclusion

The oropharyngeal space of upper airway becomes smaller and hyoid shifts downwards due to class II malocclusion. Class III malocclusion results in decreased nasopharyngeal gap with hyoid to shift upward. The influence of class II malocclusion on the upper pharyngeal tract of parents was greater than their children.

Inhibition of miR-193a-3p protects human umbilical vein endothelial cells against intermittent hypoxia-induced endothelial injury by targeting FAIM2

OBJECTIVE

The functions and molecular regulatory mechanisms of miR-193a-3p in cardiac injury induced by obstructive sleep apnea (OSA) are poorly understood. This study aimed to explore the role of miR-193a-3p in intermittent hypoxia(IH)-induced human umbilical vein endothelial cells (HUVECs) injury.

RESULTS

In this study, we found that IH significantly decreased viability but enhanced cell apoptosis. Concurrently, the miR-193a-3p expression level was increased in HUVECs after IH. Subsequent experiments showed that IH-induced injury was ameliorated through miR-193a-3p silence. Fas apoptotic inhibitory molecule 2 (FAIM2) was predicted by bioinformatics analysis and further identified as a direct target gene of miR-193a-3p. Interestingly, the effect of miR-193a-3p inhibition under IH could be reversed by down-regulating FAIM2 expression.

CONCLUSION

In conclusion, our study first revealed that miR-193a-3p inhibition could protect HUVECs against intermittent hypoxia-induced damage by negatively regulating FAIM2. These findings could advance our understanding of the underlying mechanisms for OSA-related cardiac injury.

METHODS

We exposed HUVECs to IH condition; the expression levels of miR-193a-3p were detected by RT-qPCR. Cell viability, and the expressions of apoptosis-associated proteins were examined via CCK-8, and western blotting, respectively. Target genes of miR-193a-3p were confirmed by dual-luciferase reporter assay.

Cysteinyl-leukotriene pathway as a new therapeutic target for the treatment of atherosclerosis related to obstructive sleep apnea syndrome

AIMS

Obstructive sleep apnea (OSA) characterized by nocturnal intermittent hypoxia (IH) is associated with atherosclerosis and cysteinyl-leukotrienes (CysLT) pathway activation. We aimed to identify the determinants of CysLT pathway activation and the role of CysLT in OSA-related atherosclerosis.

METHODS AND RESULTS

Determinants of the urinary excretion of LTE₄ (U-LTE₄) including history of cardiovascular events, polysomnographic and biological parameters were studied in a cohort of 170 OSA patients and 29 controls, and in a subgroup of OSA patients free of cardiovascular event (n = 136). Mechanisms linking IH, the CysLT pathway and atherogenesis were investigated in Apolipoprotein E deficient (ApoE^-/-) mice exposed to 8-week IH. In the whole cohort, U-LTE₄ was independently influenced by age, minimal oxygen saturation, and a history of cardiovascular events, and correlated significantly with intima-media thickness. In the subgroup of OSA patients free of cardiovascular event, increased U-LTE₄ was increased compared to controls and independently related to hypoxia severity and traditional risk factors aggregated in the 10-year cardiovascular risk score of European Society of Cardiology. In IH mice, atherosclerosis lesion size and mRNA levels of 5-lipoxygenase, 5-lipoxygenase activating protein (FLAP) and CysLT₁ receptor were significantly increased. This transcriptional activation was associated with the binding of HIF-1 to the FLAP promoter and was strongly associated with atherosclerosis lesion size. CysLT₁ receptor antagonism (montelukast) significantly reduced atherosclerosis progression in IH mice.

CONCLUSIONS

IH-related CysLT pathway activation contributes to OSA-induced atherogenesis. In the era of personalized medicine, U-LTE₄ may be a useful biomarker to identify OSA patients for whom CysLT₁ blockade could represent a new therapeutic avenue for reducing cardiovascular risk.