Increased plasma soluble tumor necrosis factor receptor-1 and myeloperoxidase activity in patients with obstructive sleep apnea syndrome

Evaluate the Relationship Between Obstructive Sleep Apnea and Metabolic Syndrome in Real-World Data

Objective

Obstructive sleep apnea (OSA) is a disorder characterized by disruption in breathing and hypoventilation. In parallel, metabolic syndrome (MetS) mainly co-occur with OSA, however, their association has not been fully elucidated. Therefore, this study aimed to reveal the relationship between OSA and MetS using data from the National Health And Nutrition Examination Survey (NHANES) database and pooled data from Genome-Wide Association Studies (GWAS).

Material and Methods

Data from the National Health and Nutrition Examination Survey and pooled data from genome-wide association analysis (GWAS) were used univariate and multivariate logistic regression analyses were carried out to evaluate the correlation between OSA and MetS, and multivariate logistic regression models were utilized for adjusting for potential confounders. Two-sample Mendelian randomization (MR) was used to assess the causal relationship between OSA and MetS. The variance-weighted inverse method was employed as the main method of analysis.

Results

A positive relationship of OSA with Mets was evidenced by multivariate logistic regression analysis, and OSA was associated with higher incidence rates of all-cause and cardiovascular mortality. OSA is strongly associated with abdominal obesity, hypertension, hyperglycemia, high triglycerides, and low HDL. Furthermore, except for hypertriglyceridemia, MR analysis indicated that genetically driven OSA was causally associated with a higher risk of MetS.

Conclusion

The positive relationship of OSA with Mets was revealed, and higher incidence rates of all-cause mortality and cardiovascular mortality were noted to be correlated with OSA. MR analysis further confirmed the causal relationship of OSA with MetS and cardiovascular disease.

Causal relationship between levels of myeloperoxidase and obstructive sleep apnea: a bidirectional two-sample Mendelian randomization study

Background

Several observational studies have investigated the association between myeloperoxidase (MPO) and obstructive sleep apnea (OSA). However, the nature of this relationship remains uncertain due to potential selection and confounding biases. To resolve this, we conducted a bidirectional two-sample Mendelian randomization (MR) study to scrutinize the causal relationship between MPO and OSA.

Methods

Instrumental variables (IVs) for OSA were sourced from the publicly available FinnGen dataset, encompassing 38,998 OSA cases and 336,659 controls. Data on MPO were sourced from a study of 21,758 individuals conducted by the European Bioinformatics Institute (EBI). The primary MR analysis utilized the inverse-variance weighted (IVW) method, with MR-Egger intercept and leave-one-out methods assessing pleiotropy and Cochran's Q test determining heterogeneity.

Results

The IVW analysis indicated a causal relationship between heightened MPO levels and an increased incidence of OSA. Individuals with elevated MPO levels manifested a higher propensity to develop OSA, exhibiting an odds ratio (OR) of 1.075 and a 95% confidence interval (CI) of 1.011-1.143 (p = 0.021). Conversely, the reciprocal analysis unveiled no significant association between OSA and heightened MPO levels (p = 0.643). No directional pleiotropy was identified through the MR-Egger intercept test (p > 0.05).

Conclusion

Our study provides evidence of an association between elevated MPO levels and an increased incidence of OSA. However, OSA does not necessarily lead to elevated MPO levels. When patients present with high MPO levels, screening for OSA may be advisable, considering their clinical characteristics.

Salivary Alterations of Myeloperoxidase in Patients with Systemic Diseases: A Systematic Review

Salivary myeloperoxidase (MPO) is a key mediator of the oral immune system, acting as an enzyme that utilises H2O2 to generate molecules with high bactericidal activity. While MPO determination in plasma is quite common, the use of saliva is still rare. Our systematic review was designed to answer the question "Are salivary levels of myeloperoxidase altered in patients with systemic diseases?". Following the inclusion and exclusion criteria, we included twenty-six studies. Altered MPO levels in saliva were most commonly found in patients with cardiovascular and gastrointestinal diseases. Most studies concerned unstimulated whole saliva, and only a few of them stimulated, mainly by chewing paraffin. Enzyme-linked immunosorbent assay (ELISA) was the most common method for determination of MPO concentrations in saliva. Increased salivary MPO levels were more often observed for inflammatory diseases, except patients with inflammatory bowel diseases who were eligible for biologic therapy. In conclusion, MPO could be altered in the saliva of patients with systematic diseases, especially cardiovascular or gastrointestinal diseases. However, further investigations are recommended to validate these outcomes.

Current Smoking Determines the Levels of Circulating MPO and MMP-9 in Adults with Coronary Artery Disease and Obstructive Sleep Apnea

(1) Background: Obstructive sleep apnea (OSA) is common in patients with coronary artery disease (CAD), in which a rupture of atherosclerotic plaques and oxidative stress play a role in the initiation and progression of the disorder. Circulating levels of myeloperoxidase (MPO), as an oxidative stress marker, as well as matrix metalloproteinase-9 (MMP-9), as a destabilizer of plaques, are known to be elevated in patients with CAD and are associated with worse prognosis. Some studies have suggested that OSA is associated with MPO and MMP-9, but the effect of OSA on these biomarkers in cardiac cohorts is unknown. (2) Aims: We addressed the determinants of high MPO and MMP-9 in a CAD cohort with concomitant OSA. (3) Materials and Methods: The current study was a secondary analysis of the RICCADSA trial that was conducted in Sweden between 2005 and 2013. A total of 502 revascularized CAD patients with OSA (apnea-hypopnea index [AHI] ≥ 15 events/h; n = 391) or no-OSA (AHI < 5 events/h; n = 101), based on a home sleep apnea test, and who had blood samples at baseline were included in the analysis. The patients were dichotomized into a high or low MPO and MMP-9 groups, based on the median cut-off values. (4) Results: The mean age of the participants was 63.9 (±8.6), and 84% of the study cohort were men. Median values of MPO and MMP-9 levels were 116 ng/mL and 269 ng/mL, respectively. In different multivariate linear and logistic regression models, neither OSA nor OSA severity in terms of AHI and oxygenation indices were associated with the high MPO and MMP-9 levels. Current smoking was significantly associated with both high MPO (odds ratio [OR] 1.73, 95% confidence interval [CI] 1.06-2.84; p = 0.030) and high MMP-9 levels (OR 2.41, 95% CI 1.44-4.03; p < 0.001), respectively. Other significant determinants were revealed as beta blocker use (OR 1.81, 95% CI 1.04-3.16; p = 0.036) for high MPO as well as male sex (OR 2.07, 95% CI 1.23-3.50; p = 0.006) and calcium antagonist use (OR 1.91, 95% CI 1.18-3.09; p = 0.008) for high MMP-9 levels. (5) Conclusions: Current smoking, but not OSA, was significantly associated with high MPO and MMP-9 levels in this revascularized CAD cohort. Smoking status should be seriously taken into consideration while evaluating the effects of OSA and its treatment on long-term adverse cardiovascular outcomes in adults with CAD.

Obstructive Sleep Apnoea and Lipid Metabolism: The Summary of Evidence and Future Perspectives in the Pathophysiology of OSA-Associated Dyslipidaemia

Obstructive sleep apnoea (OSA) is associated with cardiovascular and metabolic comorbidities, including hypertension, dyslipidaemia, insulin resistance and atherosclerosis. Strong evidence suggests that OSA is associated with an altered lipid profile including elevated levels of triglyceride-rich lipoproteins and decreased levels of high-density lipoprotein (HDL). Intermittent hypoxia; sleep fragmentation; and consequential surges in the sympathetic activity, enhanced oxidative stress and systemic inflammation are the postulated mechanisms leading to metabolic alterations in OSA. Although the exact mechanisms of OSA-associated dyslipidaemia have not been fully elucidated, three main points have been found to be impaired: activated lipolysis in the adipose tissue, decreased lipid clearance from the circulation and accelerated de novo lipid synthesis. This is further complicated by the oxidisation of atherogenic lipoproteins, adipose tissue dysfunction, hormonal changes, and the reduced function of HDL particles in OSA. In this comprehensive review, we summarise and critically evaluate the current evidence about the possible mechanisms involved in OSA-associated dyslipidaemia.

[The role of biomarkers in the detection of the OSA syndrome. A narrative review of the literature]

INTRODUCTION

Obstructive sleep apnoea (OSA) is a common sleep-related breath disorder associated with cardiovascular and cerebrovascular complications, such as hypertension, arrhythmia, coronary artery disease and stroke. Unfortunately, OSA is underdiagnosed.

BACKGROUND

Because of its clinical and therapeutic variability, OSA could benefit a personalized medicine approach. Diagnosis with polysomnography is expensive and access is limited. Clinical scoring systems allow screening of OSA, but many limitations exist. Because of this, biomarkers could be useful for the detection of OSA.

OUTLOOK

Biomarkers specific to OSA would allow for better mass screening and more personalized treatment of the disease. This narrative review of the literature aims to summarize the biomarkers already described for the diagnosis of OSA and clarify both their advantages and limitations in daily practice.

CONCLUSIONS

Our review of the literature did not actually identify an ideal biomarker even if promising research is ongoing.

Patients with obstructive sleep apnea have suppressed levels of soluble cytokine receptors involved in neurodegenerative disease, but normal levels with airways therapy

Purpose

Obstructive sleep apnea (OSA) results in systemic intermittent hypoxia. By one model, hypoxic stress signaling in OSA patients alters the levels of inflammatory soluble cytokines TNF and IL6, damages the blood brain barrier, and activates microglial targeting of neuronal cell death to increase the risk of neurodegenerative disorders and other diseases. However, it is not yet clear if OSA significantly alters the levels of the soluble isoforms of TNF receptors TNFR1 and TNFR2 and IL6 receptor (IL6R) and co-receptor gp130, which have the potential to modulate TNF and IL6 signaling.

Methods

Picogram per milliliter levels of the soluble isoforms of these four cytokine receptors were estimated in OSA patients, in OSA patients receiving airways therapy, and in healthy control subjects. Triplicate samples were examined using Bio-Plex fluorescent bead microfluidic technology. The statistical significance of cytokine data was estimated using the nonparametric Wilcoxon rank-sum test. The clustering of these high-dimensional data was visualized using t-distributed stochastic neighbor embedding (t-SNE).

Results

OSA patients had significant twofold to sevenfold reductions in the soluble serum isoforms of all four cytokine receptors, gp130, IL6R, TNFR1, and TNFR2, as compared with control individuals (p = 1.8 × 10⁻¹³ to 4 × 10⁻⁸). Relative to untreated OSA patients, airways therapy of OSA patients had significantly higher levels of gp130 (p = 2.8 × 10⁻¹³), IL6R (p = 1.1 × 10⁻⁹), TNFR1 (p = 2.5 × 10⁻¹⁰), and TNFR2 (p = 5.7 × 10⁻⁹), levels indistinguishable from controls (p = 0.29 to 0.95). The data for most airway-treated patients clustered with healthy controls, but the data for a few airway-treated patients clustered with apneic patients.

Conclusions

Patients with OSA have aberrantly low levels of four soluble cytokine receptors associated with neurodegenerative disease, gp130, IL6R, TNFR1, and TNFR2. Most OSA patients receiving airways therapy have receptor levels indistinguishable from healthy controls, suggesting a chronic intermittent hypoxia may be one of the factors contributing to low receptor levels in untreated OSA patients.

Electronic supplementary material

The online version of this article (10.1007/s11325-020-02205-y) contains supplementary material, which is available to authorized users.