Effects of somatotropic axis on cognitive dysfunction of obstructive sleep apnea

The Overlap Syndrome of Obstructive Sleep Apnea and Chronic Obstructive Pulmonary Disease: A Systematic Review

Chronic obstructive pulmonary disease (COPD) and obstructive sleep apnea (OSA) are common diseases that strongly impact the quality and length of life. Their coexistence is determined by overlap syndrome (OS). This systematic review aims to define the significance of these comorbidities according to the current state of knowledge. For this systematic review, we searched PubMed, Scopus, and Cochrane for studies published between 2018 and 26 October 2022, to find original, observational, human studies published in English, where the diagnosis of COPD was according to the Global Initiative for Obstructive Lung Disease guidelines and the diagnosis of OSA was based on polysomnography. The quality of studies was assessed using the Newcastle-Ottawa quality assessment tool for cohort and case-control studies, as well as its modification for cross-sectional studies. Of the 1548 records identified, 38 were eligible and included in this systematic review. The included studies covered a total population of 27,064 participants. This paper summarizes the most important, up-to-date information regarding OS, including the prevalence, meaning of age/gender/body mass index, polysomnography findings, pulmonary function, comorbidities, predicting OSA among COPD patients, and treatment of this syndrome.

Serum sTREM2: A Potential Biomarker for Mild Cognitive Impairment in Patients With Obstructive Sleep Apnea

Objective

Cognitive impairment is a common comorbidity in patients with obstructive sleep apnea (OSA) that leads to poor quality of life and a heavier medical burden. However, the assessment and longitudinal tracking of cognitive impairment in OSA is challenging. This study aimed to examine the alternation and related factors of serum soluble triggering receptor expressed on myeloid cells 2 (sTREM2) in patients with OSA, and to explore whether serum sTREM2 could be a biomarker for mild cognitive impairment in OSA patients.

Methods

A total of 94 OSA patients and 13 snoring subjects were enrolled in this cross-sectional study. Demographic information, questionnaires, and polysomnography results were collected. Serum sTREM2 levels were quantified using an enzyme-linked immunosorbent assay. Multivariate linear regression was used to analyze the factors influencing sTREM2, and the receiver operating characteristic curve was used to assess the predictive value of serum sTREM2 for mild cognitive impairment in patients with OSA.

Results

Patients with OSA had higher serum sTREM2 levels than the controls. Multivariate linear regression analysis showed that serum sTREM2 levels in patients with OSA were associated with the Montreal Cognitive Assessment score and oxygen depletion index levels. Additionally, serum sTREM2 levels were higher in OSA patients with mild cognitive impairment (MCI) than in those without. The receiver operating characteristic curve showed that at a cutoff value of >18,437 pg/ml, the sensitivity of serum sTREM2 to predict MCI in OSA was 64.62%, the specificity was 68.97%, and the area under the curve was 0.70 (95% CI: 0.58–0.81).

Conclusion

Serum sTREM2 levels were elevated in patients with OSA, particularly in those with MCI. It therefore has the potential to be a biomarker for MCI in OSA patients.

Identification of Hub Genes in Patients with Alzheimer Disease and Obstructive Sleep Apnea Syndrome Using Integrated Bioinformatics Analysis

Background

Obstructive sleep apnea syndrome (OSA) is associated with an increased risk of Alzheimer’s disease (AD). This study aimed to identify the key common genes in AD and OSA and explore molecular mechanism value in AD.

Methods

Expression profiles GSE5281 and GSE135917 were acquired from Gene Expression Omnibus (GEO) database, respectively. Weighted gene co-expression network analysis (WGCNA) and R 4.0.2 software were used for identifying differentially expressed genes (DEGs) related to AD and OSA. Function enrichment analyses using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway, and the protein–protein interaction network (PPI) using the STRING database were subsequently performed on the shared DEGs. Finally, the hub genes were screened from the PPI network using the MCC algorithm of CytoHubba plugin.

Results

Seven modules and four modules were the most significant with AD and OSA by WGCNA, respectively. A total of 33 common genes were screened in AD and OSA by VENN. Functional enrichment analysis indicated that DEGs were mainly involved in cellular response to oxidative stress, neuroinflammation. Among these DEGs, the top 10 hub genes (high scores in cytoHubba) were selected in the PPI network, including AREG, SPP1, CXCL2, ITGAX, DUSP1, COL1A1, SCD, ACTA2, CCND2, ATF3.

Conclusion

This study presented ten target genes on the basis of common genes to AD and OSA. These candidate genes may provide a novel perspective to explore the underlying mechanism that OSA leads to an increased risk of AD at the transcriptome level.

The role of obstructive sleep apnea on the prognosis of pulmonary embolism: a systemic review and meta-analysis

PURPOSE

The relationship between obstructive sleep apnea (OSA) and pulmonary embolism (PE) has been reported by some studies but the underlying mechanism remains unclear. We aimed to systematically assess the role of OSA on the disease prognosis of PE.

METHODS

We searched for studies on the relationship of OSA and the prognosis of PE published up to February 2020 among PubMed, Web of Science, EMBASE, and Cochrane Library databases. Two independent reviewers conducted the process of study search and screening, quality assessment, and data extraction. Meta-analysis was carried out using RevMan 5.3.

RESULTS

A total of 9 articles were included, and the funnel plots suggested no evidence of publication bias among studies. The results showed that compared to PE patients without OSA, the PE patients with moderate-severe OSA were more likely to be high-risk type (OR = 1.96, 95% CI [1.14, 3.34]) and with higher index of disease severity (sPESI: OR = 2.29, 95% CI [1.50, 3.47]; PAOI%: MD = 13.52, 95% CI [7.2, 19.83]). The prevalence of recurrent PE was higher in PE patients with OSA than those without OSA (RR = 3.87, 95% CI [1.65, 9.07]). However, there was no significant difference in right ventricle to left ventricle short-axis diameter (MD = 0.08, 95% CI [- 0.06, 0.21]), length of hospital stay (MD = 1.03, 95% CI [- 1.11, 3.17]), or prevalence of deep vein thrombosis (OR = 0.87, 95% CI [0.48, 1.57]). Sensitivity and subgroup analysis showed that the pooled outcomes were stable.

CONCLUSION

OSA, especially moderate-severe OSA, was a risk factor for high-risk PE and recurrent PE. However, the current evidence showed that the length of hospital stay is not influenced by OSA.

Moderate-to-Severe Obstructive Sleep Apnea and Cognitive Function Impairment in Patients with COPD

Purpose

Prior studies have indicated that patients with chronic obstructive pulmonary disease (COPD) exhibit significant cognitive defects on neuropsychological testing. Obstructive sleep apnea (OSA) is common in patients with COPD and is associated with reduced cognitive function; however, the combined impact of these two conditions on cognitive function is unknown. The aim of the study was to investigate the impact of OSA on cognitive impairment in patients with COPD.

Methods

Sixty-five stable COPD patients aged over 60 years underwent overnight polysomnography (PSG). Global cognitive functions were evaluated using the Mini-Mental State Examination (MMSE).

Results

Compared to patients with COPD alone, patients with both COPD and OSA performed worse on the MMSE (25.5±2.9 vs 23.5±3.2; p=0.01) and were more likely to be at risk for developing dementia based on the MMSE score (MMSE≤24) (31% vs 66%; p<0.01), independent of key demographic, educational and medical variables known to affect cognitive function in COPD. COPD patients with an apnea hypopnea index (AHI) of ≥30 events/h had lower MMSE scores than those with an AHI of <15 events/h. In addition to age and education level, the severity of nocturnal intermittent hypoxia is an independent predictor of the risk of dementia in patients with COPD (OR=1.24, 95% CI 1.04-1.48, p = 0.02).

Conclusion

The current findings indicate that patients with COPD with comorbid OSA may be at greater risk for global cognitive impairment relative to patients with COPD alone. The mechanisms underlying the exaggerated cognitive dysfunction seem to be related to intermittent hypoxia. Further work is needed to understand the impact of OSA on the specific domains of cognitive impairment and the therapeutic implications of OSA in COPD.

Blocking the LncRNA MALAT1/miR-224-5p/NLRP3 Axis Inhibits the Hippocampal Inflammatory Response in T2DM With OSA

Studies have shown that diabetes can cause cognitive dysfunction, and cognitive dysfunction in patients with diabetes combined with obstructive sleep apnea (OSA) is more severe. LncRNAs are known to be associated with type 2 diabetes mellitus (T2DM) with OSA. This study aimed to investigate the role and underlying mechanism of the lncRNA MALAT1/miR-224-5p/NLRP3 axis in T2DM with OSA. qRT-PCR was used to quantify the expression of MALAT1, miR-224-5p, and NLRP3 in brain tissues. NLRP3 expression was assessed by immunohistochemistry (IHC) and immunofluorescent labeling. The interaction involving MALAT1, miR-224-5p, and NLRP3 was evaluated by transfection. Western blotting was utilized to evaluate the expression levels of the pathway-related proteins NLRP3, caspase 1, tumor necrosis factor-α (TNF-α) and interleukin-1 β (IL-1β) both in vitro and in vivo. qRT-PCR was used to assess the mRNA expression levels of NLRP3, caspase 1, TNF-α and IL-1β both in vitro and in vivo. In brain tissues of T2DM with OSA, MALAT1 and NLRP3 were overexpressed, while miR-224-5p was downregulated, which was consistent with subsequent cell experiments. We screened the miRNAs that could bind to MALAT1 and NLRP3 by the StarBase database and the TargetScanMouse7.2 website. Our research showed that among these miRNAs, the level of miR-224-5p was most significantly negatively correlated with the levels of MALAT1 and NLRP3. Also, a firefly luciferase assay showed that miR-224-5p, which is a target of MALAT1, directly reduced the expression of the downstream protein NLRP3. Overexpression of miR-224-5p significantly inhibited the expression levels of NLRP3, caspase 1, TNF-α and IL-1β in vitro. MALAT1 promoted NLRP3 expression by acting as a competing endogenous RNA and sponging miR-224-5p. MiR-224-5p reduces microglial inflammation activation through the regulation of NLRP3 expression, which ultimately affected the NLRP3/IL-1β pathway in the hippocampus. This suggests that miR-224-5p may serve as a potential target for T2DM and OSA therapy.