Blood biomarkers of endocrine, immune, inflammatory, and metabolic systems in obstructive sleep apnea

Longer-term impacts of the COVID-19 pandemic on obstructive sleep apnoea (OSA)-related healthcare: a province-based study

RATIONALE

Following marked reductions in sleep medicine care early in the COVID-19 pandemic, there is limited information about the recovery of these services. We explored long-term trends in obstructive sleep apnoea (OSA) health services and service backlogs during the pandemic compared with pre-pandemic levels in Ontario (the most populous province of Canada).

METHODS

In this retrospective population-based study using Ontario (Canada) health administrative data on adults, we compared rates of polysomnograms (PSGs), outpatient visits and positive airway pressure (PAP) therapy purchase claims during the pandemic (March 2020 to December 2022) to pre-pandemic rates (2015-2019). We calculated projected rates using monthly seasonal time series auto-regressive integrated moving-average models based on similar periods in previous years. Service backlogs were estimated from the difference between projected and observed rates.

RESULTS

Compared with historical data, all service rates decreased at first during March to May 2020 and subsequently increased. By December 2022, observed service rates per 100 000 persons remained lower than projected for PSGs (September to December 2022: 113 vs 141, 95% CI: 121 to 163) and PAP claims (September to December 2022: 50 vs 60, 95% CI: 51 to 70), and returned to projected for outpatient OSA visits. By December 2022, the service backlog was 193 078 PSGs (95% CI: 139 294 to 253 075) and 57 321 PAP claims (95% CI: 27 703 to 86 938).

CONCLUSION

As of December 2022, there was a sustained reduction in OSA-related health services in Ontario, Canada. The resulting service backlog has likely worsened existing problems with underdiagnosis and undertreatment of OSA and supports the adoption of flexible care delivery models for OSA that include portable technologies.

Effects of the antipsychotic quetiapine on sleep and breathing: a review of clinical findings and potential mechanisms

Quetiapine is an antipsychotic medication indicated for schizophrenia and bipolar disorder. However, quetiapine also has hypnotic properties and as such is increasingly being prescribed at low doses 'off-label' in people with insomnia symptoms. Pharmacologically, in addition to its dopaminergic properties, quetiapine also modulates multiple other transmitter systems involved in sleep/wake modulation and potentially breathing. However, very little is known about the impact of quetiapine on obstructive sleep apnoea (OSA), OSA endotypes including chemosensitivity, and control of breathing. Given that many people with insomnia also have undiagnosed OSA, it is important to understand the effects of quetiapine on OSA and its mechanisms. Accordingly, this concise review covers the existing knowledge on the effects of quetiapine on sleep and breathing. Further, we highlight the pharmacodynamics of quetiapine and its potential to alter key OSA endotypes to provide potential mechanistic insight. Finally, an agenda for future research priorities is proposed to fill the current key knowledge gaps.

Preoperative sleep apnea screening protocol reduces medical emergency team activation in patients with atrial fibrillation

STUDY OBJECTIVES

The association of in-hospital medical emergency team activation (META) among patients with atrial fibrillation (AF) at risk for obstructive sleep apnea (OSA) is unclear. This study evaluates the performance of the DOISNORE50 sleep questionnaire as an OSA screener for patients with AF and determines the prevalence of META among perioperative patients with underlying AF who have a diagnosis or are at risk for OSA.

METHODS

A prospective perioperative cohort of 2,926 patients with the diagnosis of AF was assessed for DOISNORE50 questionnaire screening. Propensity-score matching was used to match patients' physical characteristics, comorbidities, length of stay, and inpatient continuous positive airway pressure device usage. META and intensive care unit admissions during the surgical encounter, 30-day hospital readmissions, and 30-day emergency department visits were evaluated.

RESULTS

A total of 1,509 out of 2,926 AF patients completed the DOISNORE50 questionnaire and were enrolled in the OSA safety protocol. Following propensity-score matching, there were reduced adjusted odds of META in the screened group of 0.69 (95% confidence interval: 0.48-0.98, P < .001) in comparison to the unscreened group. The adjusted odds of intensive care unit admissions and emergency department visits within 30 days of discharge were statistically lower for the screened group compared with the unscreened group.

CONCLUSIONS

Among perioperative AF patients, evidence supports DOISNORE50 screening and implementation of an OSA safety protocol for reduction of META. This study identified decreased odds of META, intensive care unit admissions, and emergency department visits among the screened group. The high-risk and known OSA group showed reduced odds of META following the implementation of an OSA safety protocol.

CITATION

Saha AK, Sheehan KN, Xiang KR, et al. Preoperative sleep apnea screening protocol reduces medical emergency team activation in patients with atrial fibrillation. J Clin Sleep Med. 2024;20(5):783-792.

Identification of biomarkers and pathways for the SARS-CoV-2 infections in obstructive sleep apnea patients based on machine learning and proteomic analysis

BACKGROUND

The prevalence of obstructive sleep apnea (OSA) was found to be higher in individuals following COVID-19 infection. However, the intricate mechanisms that underscore this concomitance remain partially elucidated. The aim of this study was to delve deeper into the molecular mechanisms that underpin this comorbidity.

METHODS

We acquired gene expression profiles for COVID-19 (GSE157103) and OSA (GSE75097) from the Gene Expression Omnibus (GEO) database. Upon identifying shared feature genes between OSA and COVID-19 utilizing LASSO, Random forest and Support vector machines algorithms, we advanced to functional annotation, analysis of protein-protein interaction networks, module construction, and identification of pivotal genes. Furthermore, we established regulatory networks encompassing transcription factor (TF)-gene and TF-miRNA interactions, and searched for promising drug targets. Subsequently, the expression levels of pivotal genes were validated through proteomics data from COVID-19 cases.

RESULTS

Fourteen feature genes shared between OSA and COVID-19 were selected for further investigation. Through functional annotation, it was indicated that metabolic pathways play a role in the pathogenesis of both disorders. Subsequently, employing the cytoHubba plugin, ten hub genes were recognized, namely TP53, CCND1, MDM2, RB1, HIF1A, EP300, STAT3, CDK2, HSP90AA1, and PPARG. The finding of proteomics unveiled a substantial augmentation in the expression level of HSP90AA1 in COVID-19 patient samples, especially in severe conditions.

CONCLUSIONS

Our investigation illuminate a mutual pathogenic mechanism that underlies both OSA and COVID-19, which may provide novel perspectives for future investigations into the underlying mechanisms.

Association of clinically significant obstructive sleep apnoea with risks of contracting COVID-19 and serious COVID-19 complications: a retrospective population-based study of health administrative data

RATIONALE/OBJECTIVES

Despite plausible pathophysiological mechanisms, more research is needed to confirm the relationship between obstructive sleep apnoea (OSA) and the risk of COVID-19 infection or COVID-19-related serious complications.

METHODS

We conducted a retrospective population-based cohort study using provincial health administrative data (Ontario, Canada). Adults with physician-diagnosed OSA who received positive airway pressure therapy in the 5 years prepandemic (OSA group) were propensity score matched by baseline characteristics to individuals in the general population at low risk of OSA (non-OSA group) using inverse probability of treatment weighting. Weighted HRs of (1) a positive COVID-19 test and (2) COVID-19-related emergency department (ED) visits, hospitalisations, intensive care unit (ICU) admissions and mortality, within 12 months of pandemic onset, were compared between groups. We also evaluated the impact of comorbid cardiometabolic or chronic airways disease.

RESULTS

We identified and matched 324 029 individuals in the OSA group to 4 588 200 individuals in the non-OSA group. Compared with the non-OSA group, those in the OSA group were at a greater hazard of testing positive for COVID-19 (HR=1.17, 95% CI 1.13 to 1.21), having a COVID-19-related ED visit (HR=1.62, 95% CI 1.51 to 1.73), hospitalisation (HR=1.50, 95% CI 1.37 to 1.65) or ICU admission (HR=1.53, 95% CI 1.27 to 1.84). COVID-19-related 30-day mortality was not different (HR=0.98, 95% CI 0.82 to 1.16).We found that for the OSA group, comorbid airways disease but not cardiometabolic conditions increased the hazards of COVID-19-related outcomes, including mortality.

CONCLUSION

In this large population-based study, we demonstrated that a recent diagnosis of OSA requiring treatment was associated with an increased hazard of testing positive for COVID-19 and serious COVID-19-related complications, particularly in those with co-existing chronic airways disease.

Not-So-Sweet Dreams: Plasma and IgG N-Glycome in the Severe Form of the Obstructive Sleep Apnea

Obstructive sleep apnea (OSA) is a prevalent disease associated with increased risk for cardiovascular and metabolic diseases and shortened lifespan. The aim of this study was to explore the possibility of using N-glycome as a biomarker for the severe form of OSA. Seventy subjects who underwent a whole-night polysomnography/polygraphy and had apnea-hypopnea index (AHI) over 30 were compared to 23 controls (AHI under 5). Plasma samples were used to extract 39 glycan peaks using ultra-high-performance liquid chromatography (UPLC) and 27 IgG peaks using capillary gel electrophoresis (CGE). We also measured glycan age, a molecular proxy for biological aging. Three plasma and one IgG peaks were significant in a multivariate model controlling for the effects of age, sex, and body mass index. These included decreased GP24 (disialylated triantennary glycans as major structure) and GP28 (trigalactosylated, triantennary, disialylated, and trisialylated glycans), and increased GP32 (trisialylated triantennary glycan). Only one IgG glycan peak was significantly increased (P26), which contains biantennary digalactosylated glycans with core fucose. Patients with severe OSA exhibited accelerated biological aging, with a median of 6.9 years more than their chronological age (p < 0.001). Plasma N-glycome can be used as a biomarker for severe OSA.

Changes in Positive Airway Pressure Use in Adults with Sleep-Related Breathing Disorder During the COVID-19 Pandemic: A Cross-Sectional National Community-Based Survey

Purpose

Methods

Results

Conclusions

Circulating ADAMTS13 Levels Are Associated with an Increased Occurrence of Obstructive Sleep Apnea

Background and Aims. Obstructive sleep apnea (OSA) is strongly associated with obesity, metabolic diseases, coronary artery disease (CAD), stroke, hypertension, and other disorders. This study assessed the relationship between circulating a disintegrin and metalloprotease with a thrombospondin type 1 motif, member 13 (ADAMTS13) levels and the presence of OSA. Materials and Methods. This cross-sectional study included a total of 223 patients. We used a powerful high-throughput multiplexed immunobead-based assay to detect circulating levels of ADAMTS13. The associations between circulating ADAMTS13 levels and OSA were evaluated by multivariate logistic regression analysis. Results. Circulating ADAMTS13 levels were significantly elevated in patients with OSA compared with controls (0.8 vs. 2.7 μg/mL, respectively, $P<0.001$ ). After adjusting for confounding factors, circulating ADAMTS13 levels were significantly independently associated with the presence of OSA ( $\text{odds}\text{ratio}=9.96$ , 95% confidence interval (CI) =4.11–24.13, $P<0.001$ ). Furthermore, circulating ADAMTS13 levels showed discriminatory accuracy in assessing the presence of OSA (area under the curve: 0.87, 95% CI 0.81–0.93, $P<0.001$ ). Conclusion. Circulating ADAMTS13 levels were significantly correlated with the presence of OSA. ADAMTS13 may therefore function as a novel biomarker for monitoring the development and progression of OSA.

Blood Inflammatory Cytokines as Predictors of Depression in Patients With Glioma

BACKGROUND

Depression commonly develops as a comorbid disorder related to glioma, which affects the patients' physical function and prognosis. Circulating inflammatory cytokines are potential predictors of depression in disparate cancers. However, less research has specifically investigated this aspect within the context of glioma.

STUDY OBJECTIVES

The objective of this study was to investigate the occurrence of depression in patients with glioma and draw a comparison of the ability to predict it through diverse inflammatory cytokines.

METHODS

A total of 203 patients with stage I-IV glioma were enrolled in this study. Depression was evaluated according to the Hamilton Depression Scale, and the plasma inflammatory cytokines levels were simultaneously measured. We performed the receiver operating characteristic (ROC) analysis to confirm the abilities of identified inflammatory cytokines to predict depression.

RESULTS

Among the 203 patients with glioma, 135 (66.5%) showed obvious depressive symptoms. Proinflammatory cytokines, including interleukin (IL)-6 (area under the curve (AUC) = 0.76) and tumor necrosis factor (TNF)-α (AUC = 0.75), showed good performance in accurately predicting depression in patients with glioma. These inflammatory cytokines indicated great potential to be depression biomarkers regardless of the patients' disparate treatment experience.

CONCLUSION

With their relatively simple and time-saving measurement procedures, inflammatory cytokines should be seriously considered effective clinical screening and diagnostic tools, as well as potential biomarkers for depression in patients with glioma.

Erythropoietin levels in children with obstructive sleep apnea

OBJECTIVE

High serum erythropoietin (EPO) levels have been reported in adult patients with obstructive sleep apnea (OSA), however there is a lack of related literature in children with OSA. The main objective of this study was to explore the potential use of EPO as a pediatric OSA biomarker by exploring the relationship between serum EPO levels and the presence of pediatric OSA.

METHODS AND MATERIALS

A prospective study was conducted on children (4-12 years old) referred for overnight PSG. Thirty (30) consecutive children with mild. 30 consecutives with moderate, and 30 consecutives with severe OSA (OSA group), as well as 30 consecutive children with AHI≤1 (non-OSA group) were recruited. Morning blood specimens after PSG studies were obtained in order to compare EPO levels.

RESULTS

Finally, 115 children included for analysis. Non-OSA group consisted of 29 children (mean age: 6.93 ± 2.10) and OSA-group of 86 children (mean age: 6.78 ± 2.53). Mean EPO values for the non-OSA and OSA groups were 5.46 ± 2.29 mIU/ml and 8.33 ± 4.10 mIU/ml respectively. OSA-group had significant higher EPO levels than non-OSA (P: 0.01) while EPO levels were significantly correlated with AHI (p < 0.001).

CONCLUSION

Our study showed that serum EPO levels of children with OSA are significantly higher than those without OSA and correlate significantly with AHI. These results suggest that EPO may be considered as a biomarker candidate for pediatric OSA. Since this may be the first study on the topic further research is needed.

Putative associations between inflammatory biomarkers, obesity, and obstructive sleep apnea

BACKGROUND:

Previous studies have reported increased levels of inflammatory mediators in patients with obstructive sleep apnea (OSA), but their relation with the severity of OSA is controversial.

OBJECTIVE:

To address potential relationships between OSA-related inflammatory markers, namely, C-reactive protein (CRP), interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), and fibrinogen, with different oxygenation parameters and with BMI.

METHODS:

All eligible patients with suspected OSA newly referred to the Sleep Medicine Research Center at King Abdulaziz University Hospital, Jeddah, were evaluated demographically and anthropometrically, and underwent overnight polysomnography. Fasting morning blood samples were collected to measure serum levels of CRP, fibrinogen, TNF-α, and IL-6. Potential correlations between these inflammatory mediators and severity measures of OSA and body mass index (BMI) were explored.

RESULTS:

Sixty-four patients completed the study (40 with OSA and 24 without OSA). Significantly increased levels of CRP, fibrinogen, IL-6, and TNF-α emerged in patients with OSA compared to non-OSA. Significant associations between log CRP and log fibrinogen levels emerged with increasing BMI. However, there was no significant association between any of the inflammatory markers and the severity of OSA based on the apnea/hypopnea index or oxyhemoglobin saturation-derived parameters.

CONCLUSIONS:

OSA patients exhibit increased levels of inflammatory mediators that do not appear to be associated with polysomnographic measures, but exhibit positive correlation with the degree of adiposity.

[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.

The Impact of Obstructive Sleep Apnea on the Sleep of Critically Ill Patients

Obstructive sleep apnea is becoming increasingly prevalent in society and thus critical care practitioners need to be prepared to care for these patients in the intensive care unit. Preparation begins with equipping the critical care nurse with the knowledge necessary to provide interventions which can enhance patient outcomes and mitigate complications.

Proteomic biomarkers of sleep apnea

STUDY OBJECTIVES

Obstructive sleep apnea (OSA) is characterized by recurrent partial to complete upper airway obstructions during sleep, leading to repetitive arousals and oxygen desaturations. Although many OSA biomarkers have been reported individually, only a small subset have been validated through both cross-sectional and intervention studies. We sought to profile serum protein biomarkers in OSA in unbiased high throughput assay.

METHODS

A highly multiplexed aptamer array (SomaScan) was used to profile 1300 proteins in serum samples from 713 individuals in the Stanford Sleep Cohort, a patient-based registry. Outcome measures derived from overnight polysomnography included Obstructive Apnea Hypopnea Index (OAHI), Central Apnea Index (CAI), 2% Oxygen Desaturation index, mean and minimum oxygen saturation indices during sleep. Additionally, a separate intervention-based cohort of 16 individuals was used to assess proteomic profiles pre- and post-intervention with positive airway pressure.

RESULTS

OAHI was associated with 65 proteins, predominantly pathways of complement, coagulation, cytokine signaling, and hemostasis which were upregulated. CAI was associated with two proteins including Roundabout homolog 3 (ROBO3), a protein involved in bilateral synchronization of the pre-Bötzinger complex and cystatin F. Analysis of pre- and post intervention samples revealed IGFBP-3 protein to be increased while LEAP1 (Hepicidin) to be decreased with intervention. An OAHI machine learning classifier (OAHI >=15 vs OAHI<15) trained on SomaScan protein measures alone performed robustly, achieving 76% accuracy in a validation dataset.

CONCLUSIONS

Multiplex protein assays offer diagnostic potential and provide new insights into the biological basis of sleep disordered breathing.

Sleep apnea, "the Ugly Duckling of the Cinderellas" in cardiovascular prevention and rehabilitation

Cardiovascular diseases are the leading cause of death and account for the largest share of health expenditure worldwide, mainly invested in hospital and secondary care. Prevention and rehabilitation strategies are nearly neglected, therefore "the Cinderellas," in the health-care budget. The World Health Organization has proposed cost-effective interventions to reduce the impact of cardiovascular diseases that include polydrug treatment for hypertension and diabetes, counselling, diet, exercise, and others. Obstructive sleep apnea is not even mentioned among these interventions; consequently, it could be "the Ugly Duckling of the Cinderellas." Obstructive sleep apnea (OSA) is characterized by the presence of obstructive apneas or hypopneas during sleep, accompanied by hypoxia; and it is a highly prevalent but under-diagnosed condition. Although awareness of sleep apnea has recently increased most facts about it remains ignored by many. Robust evidence suggests that OSA is associated with, or is an independent risk factor for, hypertension, cerebrovascular disease, ischemic heart disease, heart failure and arrhythmias and that its prevalence among some of these cardiovascular diseases is higher than 80%. The efficacy of continuous positive airway pressure treatment for obstructive sleep apnea has been established. If obstructive sleep apnea plays a significant role in cardiovascular diseases, then screening and timely appropriate treatment could reduce morbidity and mortality. Thus, the public health and economic impact of these conditions could be included in the "best buy" list of interventions. This narrative review discusses the relationship between OSA and cardiovascular diseases and how neglected the link is.

Associations of sleep characteristics with atopic disease: a cross-sectional study among Chinese adolescents

Background

Adolescence, as a transition between childhood and adulthood, is a critical stage for the long-term control of atopic diseases. We aim to determine if sleep characteristics are involved in the increased risk of atopic disease among adolescents.

Methods

Adopting the stratified cluster random sampling method, this cross-sectional survey included 4932 participants aged 12–18 years. The Chinese version of adolescent sleep disturbance questionnaire and the adolescent sleep hygiene scale were used to collect information on sleep problems and sleep hygiene, respectively. Logistic regression models were implemented to examine the associations of sleep with atopic diseases.

Results

Sleep duration was not found to be related with allergic diseases. By contrast, sleep-disordered breathing was associated with an increased risk of asthma (adjusted OR = 1.79, 95% CI 1.25–2.55), allergic rhinitis (adjusted OR = 1.95, 95% CI 1.52–2.49), and eczema (adjusted OR = 1.63, 95% CI 1.23–2.16); poor sleep physiology was correspondent to increased odds of asthma (adjusted OR = 1.69, 95% CI 1.24–2.29), allergic rhinitis (adjusted OR = 1.40, 95% CI 1.13–1.73) and eczema (adjusted OR = 1.66, 95% CI 1.32–2.09); non-optimal sleep environment was associated with an increased prevalence of asthma (adjusted OR = 1.52, 95% CI 1.08–2.12), allergic rhinitis (adjusted OR = 1.32, 95% CI 1.04–1.69) and eczema (adjusted OR = 1.53, 95% CI 1.19–1.96).

Conclusions

As sleep-disordered breathing, poor sleep physiology and non-optimal sleep environment were associated with a higher risk of allergic diseases, the results of this study provide a new concept for the adjuvant treatment of allergic diseases in adolescents. Management strategies of allergic diseases should take regular screening and targeted treatment of sleep issues into account.

Machine and Deep Learning in Molecular and Genetic Aspects of Sleep Research

Epidemiological sleep research strives to identify the interactions and causal mechanisms by which sleep affects human health, and to design intervention strategies for improving sleep throughout the lifespan. These goals can be advanced by further focusing on the environmental and genetic etiology of sleep disorders, and by development of risk stratification algorithms, to identify people who are at risk or are affected by, sleep disorders. These studies rely on comprehensive sleep-related data which often contains complex multi-dimensional physiological and molecular measurements across multiple timepoints. Thus, sleep research is well-suited for the application of computational approaches that can handle high-dimensional data. Here, we survey recent advances in machine and deep learning together with the availability of large human cohort studies with sleep data that can jointly drive the next breakthroughs in the sleep-research field. We describe sleep-related data types and datasets, and present some of the tasks in the field that can be targets for algorithmic approaches, as well as the challenges and opportunities in pursuing them.

Elevated serum calprotectin as an inflammatory marker in obstructive sleep apnea

OBJECTIVE

To investigate the serum calprotectin (SCal) levels and neutrophil/lymphocyte ratio (NLR) values in patients with obstructive sleep apnea (OSA).

METHODS

Sixty-seven OSA patients and 46 healthy volunteers without any sleep disorders were included in the study. The patient group was divided into three subgroups according to the severity of OSA. The SCal levels and NLR values were compared among subgroups and between the experimental and control groups.

RESULTS

The mean SCal level and NLR value were higher in the study group than in the control group (p = 0.002 and p = 0.001, respectively). The SCal levels were significantly higher in patients with severe OSA than in those with moderate and mild OSA (p = 0.004 and p = 0.001, respectively).

DISCUSSION

Unlike NLR, the SCal level may inform the severity of OSA and could be used as an indicator for OSA.

Behavioural and emotional profiles of children and adolescents with disorders of arousal

Disorders of arousals are common sleep disorders characterized by complex motor behaviours that arise episodically out of slow-wave sleep. Psychological distress has long been associated with disorders of arousal, but this link remains controversial, especially in children and adolescents. The aim of this multi-centre study was to characterize behavioural and emotional problems in a sample of children/adolescents with disorders of arousal, and to explore their relationship with the severity of nocturnal episodes. The parents of 41 children/adolescents with a diagnosis of disorders of arousal (11.5 ± 3.3 years old, 61% males) and of a group of 41 age- and gender-matched control participants filled in the Child Behavior Checklist, along with the Sleep Disturbance Scale for Children and the Paris Arousal Disorders Severity Scale. Multilevel t-tests revealed significantly higher total scores and sub-scores of the Child Behavior Checklist for the patient group compared with the control group. Thirty-four percent of the patients obtained pathological total scores, and 12% of them borderline scores. The severity of emotional/behavioural problems in the patient group was positively correlated with the severity of the nocturnal episodes. Interestingly, children/adolescents with disorders of arousal also obtained higher excessive daytime sleepiness and insomnia symptoms sub-scores at the Sleep Disturbance Scale for Children. These results confirmed the hypothesis that behavioural/emotional problems are surprisingly common in children/adolescents with disorders of arousal. Further studies are warranted to investigate the causal relationship between pathological manifestations, subtler sleep abnormalities, and diurnal emotional/behavioural problems in children/adolescents with disorders of arousal.

Plasma expression of HIF-1α as novel biomarker for the diagnosis of obstructive sleep apnea-hypopnea syndrome

Background

Obstructive sleep apnea‐hypopnea syndrome (OSAHS) is a common breathing disorder during sleep with potential lethality and multi‐complications. Polysomnography (PSG) is now the golden standard for the diagnosis obstructive sleep apnea‐hypopnea syndrome. However, PSG is expensive and time‐consuming. Therefore, it is important to find inexpensive and convenient biomarkers for the diagnosis of OSAHS.

Objective

The present study aimed to explore the potential diagnostic value of HIF‐1α for OSAHS and its clinical significance.

Methods

This study consisted of 368 patients admitted to the sleep laboratory. The patients were classified according to their apnea‐hypopnea index (AHI) scores as OSA negative (AHI < 5), mild‐moderate (AHI:5‐30), and severe OSA (AHI > 30), and severe OSA treated with continuous positive airway pressure (CPAP). qRT‐PCR was used to detect mRNA levels in the plasma; Pearson's correlation analysis was performed to analyze the correlation of HIF‐1α mRNA level and the clinicopathological factors of OSAHS; ROC curve was constructed to evaluate the diagnostic value of HIF‐1α mRNA.

Results

HIF‐1α mRNA was significantly up‐regulated in the plasma of OSAHS patients, especially patients with severe OSAHS. HIF‐1α mRNA was positively correlated with the AHI and ODI but negatively correlated with the mean oxygen saturation in patients with OSAHS. Results of ROC curve showed that HIF‐1α is a sensitive biomarker for the diagnosis of OSAHS, especially severe OSAHS.

Conclusions

HIF‐1α mRNA might be used as s a convenient and inexpensive method for triaging OSAHS patients PSG assessment in the hospital and evaluate the curative effect.

EMMPRIN: A potential biomarker for predicting the presence of obstructive sleep apnea

BACKGROUND

Obstructive Sleep Apnea (OSA) is a sleep-related breathing disorder which is strongly associated with the development of cardiovascular diseases. The aim of the study was to investigate the association between circulating extracellular matrix metalloproteinase inducer (EMMPRIN) and OSA risk.

METHODS

This was a cross-sectional study in which a total of 144 patients were recruited. Demographic data, blood biochemical parameters and polysomnography parameters were collected. We used a powerful high-throughput Multiplex Immunobead Assay technique to simultaneously detect circulating levels of EMMPRIN and E-selectin.

RESULTS

Circulating levels of EMMPRIN were significantly increased in patients with OSA compared to controls (7.58[6.21-8.80] vs 1.47[0.80-5.91] ng/ml, P < 0.001). After adjusting for confounding factors, we found that circulating EMMPRIN levels were independently associated with the presence of OSA (odds ratio[OR] = 2.240, 95% confidence interval [CI] = 1.391-3.607, P < 0.001). Furthermore, circulating EMMPRIN showed greater discriminatory accuracy in predicting the presence of OSA (AUC:0.904).

CONCLUSIONS

Circulating EMMPRIN levels were significantly increased in patients with OSA, and may be a novel marker for predicting the risk of OSA.

Diagnostic Value of Sestrin2 in Patients with Obstructive Sleep Apnea

Background: Obstructive sleep apnea (OSA) is a serious threat to individual health. Diagnosis of OSA is mainly polysomnography (PSG). However, PSG monitoring is costly and time-consuming. At present, increasing studies are exploring new diagnostic methods for OSA. This study aimed to explore the diagnostic role of Sestrin2 in OSA.

Materials and Methods: Sixty-four subjects were recruited in this study. The concentration of plasma Sestrin2 of all subjects were measured and compared. Spearman's correlation analysis was used to investigate the correlation between plasma Sestrin2 concentration and other factors. Receiver-operating characteristic (ROC) curve was used to investigate the role of Sestrin2 in the diagnosis of OSA, moderate-severe and severe OSA.

Results: Subjects were divided into OSA group (n = 38) and control (n = 26). Levels of Plasma Sestrin2 were significantly higher in OSA patients than in controls. Sestrin2 was positively correlated with oxygen reduction index and negatively correlated with mean oxygen saturation and lowest oxygen saturation. The area under ROC curve (AUC) of Sestrin2 for OSA diagnosis was 0.740 [95% confidence interval (CI), 0.615–0.842], the cutoff value was 1.86 ng/mL, and the sensitivity and specificity were 81.58% and 61.54%, respectively. The AUC of Sestrin2 for the diagnosis of severe OSA was 0.801 (95% CI, 0.682–0.890), and the cutoff value was 5.21 ng/mL exhibiting the sensitivity and specificity of 61.90% and 90.70%, respectively.

Conclusion: Setrin2 is a marker for OSA and may be helpful in the diagnosis of OSA.

Oropharyngeal Microbiome in Obstructive Sleep Apnea: Decreased Diversity and Abundance

STUDY OBJECTIVES

To explore and analyze diversity and abundance of oropharyngeal microbiota in patients with obstructive sleep apnea (OSA).

METHODS

This was a cross-sectional study. Middle-aged men, suspected to have OSA, referred to full-night polysomnography, and willing to provide oropharyngeal swab samples, were consecutively enrolled. OSA severity was assessed by apnea-hypopnea index (AHI) as non-OSA (AHI < 5 events/h) and OSA (AHI ≥ 15 events/h). Bacterial DNA of oropharyngeal samples was extracted and quality test performed. Oropharyngeal microbiota was analyzed using 16S ribosomal DNA (rDNA) sequencing, and bioinformatic analysis carried out after sequencing.

RESULTS

Samples from 51 men (25 in the non-OSA group and 26 in the OSA group) were sent for examination. Of these, 40 samples were found to have sufficient concentration of DNA and were analyzed for bioinformatics. In alpha diversity analysis, the OSA group exhibited significantly lower sobs (198.33 ± 21.71 versus 216.57 ± 26.21, P = .022), chao (221.30 ± 26.62 versus 243.86 ± 26.20, P = .014), ace (222.17 ± 27.15 versus 242.42 ± 25.81, P = .028) and shannon index (3.14 ± 0.23 versus 3.31 ± 0.26, P = .035), suggesting a reduction in microbial species diversity. We further divided participants into non-OSA, moderate OSA, and severe OSA groups and observed a significant decrease in the bacterial biodiversity of OSA groups compared with the non-OSA group, with the most significant decrease occurring in the moderate OSA group. Principal coordinate analysis showed two extremely different oropharyngeal microbial communities in non-OSA and OSA groups. More interestingly, proportion of Neisseria was slightly higher in the severe OSA group (20.64%), followed by the moderate OSA and non-OSA groups (12.57% and 9.69%, respectively). Glaciecola was not detected in the OSA groups compared to the non-OSA group (0 versus 0.772 ± 0.4754, P < .001).

CONCLUSIONS

Middle-aged men with OSA showed less oropharyngeal species diversity and altered abundance, on which further confirmation is warranted.

Sleepiness as a Local Phenomenon

Sleep occupies a third of our life and is a primary need for all animal species studied so far. Nonetheless, chronic sleep restriction is a growing source of morbidity and mortality in both developed and developing countries. Sleep loss is associated with the subjective feeling of sleepiness and with decreased performance, as well as with detrimental effects on general health, cognition, and emotions. The ideas that small brain areas can be asleep while the rest of the brain is awake and that local sleep may account for at least some of the cognitive and behavioral manifestations of sleepiness are making their way into the scientific community. We herein clarify the different ways sleep can intrude into wakefulness, summarize recent scientific advances in the field, and offer some hypotheses that help framing sleepiness as a local phenomenon.

Serum testosterone/cortisol ratio in people with obstructive sleep apnea

Objectives

Obstructive sleep apnea (OSA) is a major health problem that has been associated with endocrine dysfunction in the hypothalamic‐pituitary‐gonadal (HPG) and hypothalamic‐pituitary‐adrenal (HPA) axes. This study investigated cortisol, testosterone, and the testosterone/cortisol ratio in patients with OSA compared to normal sleepers.

Methods

Thirty‐nine OSA patients diagnosed by overnight polysomnography (PSG) were divided into three groups, including ten mild OSA patients, 16 patients with moderate OSA, and 13 patients with severe OSA according to the apnea‐hypopnea index (AHI). In addition, 13 normal sleepers with normal PSG findings were recruited as the control group. Serum levels of cortisol, testosterone, and sex hormone‐binding globulin (SHBG) were measured using enzyme‐linked immunosorbent assay (ELISA).

Results

There were no significant differences between the normal sleepers and the three subtypes of OSA in terms of total and free testosterone levels (P > .1). The results showed significantly higher levels of cortisol in the severe OSA group compared to the normal sleepers and the two other subtypes of OSA (P < .01). In addition, the testosterone/cortisol (T/C) ratio was significantly lower among the severe OSA compared to the moderate OSA patients (P = .01). A significant correlation was observed between minimal SpO2 and AHI (r=−0.69, P < .01), cortisol and AHI (r = .47, P < .01) and cortisol and minimal SpO2 (r = −.26, P = .06).

Conclusion

According to the findings, OSA is linked to HPA axis activity in severe OSA patients but not among the mild and moderate subtypes of the disorder.

Excessive daytime sleepiness in obstructive sleep apnea: implications for driving licenses

PURPOSE

Excessive daytime sleepiness (EDS) while driving is a major international public health issue resulting in a more than doubled risk of motor vehicle accidents (MVAs). Obstructive sleep apnea (OSA) is the most frequent medical cause of EDS. Therefore, the European Union Directive 2014/85/EU determined that "untreated moderate to severe OSA coincident with EDS constitutes a medical disorder leading to unfitness to drive." The paper aims are to provide a brief review of sleepiness and its implications for driving safety, as well as to describe the subjective and objective methods to accurately evaluate EDS in order to assess fitness to drive in patients with OSA.

METHODS

We examined databases including PubMed, Medline, and EMBASE using the search terms "sleepiness at the wheel, excessive daytime sleepiness, sleepiness measure, sleep-wake cycle, obstructive sleep apnea, driving license, fitness to drive."

RESULTS

Significant interindividual variability in EDS exists in patients with comparable severity of OSA. Objective methods of measuring EDS are too expensive and time consuming to be suitable for the certification of driving licenses. The reliability of subjective methods depends upon the clinical setting and subjective tools assess only limited aspects of EDS. Objective measures, such as biochemical biomarkers, must, therefore, support subjective methods.

CONCLUSIONS

Extensive data have supported different subjective and objective methods for the appraisal of EDS in patients with OSA depending upon the clinical and experimental setting. Challenges remain to determine an appropriate tool for the evaluation of fitness to drive.

Obstructive sleep apnea and the metabolic syndrome: The road to clinically-meaningful phenotyping, improved prognosis, and personalized treatment

Obstructive sleep apnea (OSA) is an increasingly prevalent sleep disorder characterized by upper airway obstruction during sleep, resulting in breathing pauses, intermittent hypoxia, and fragmented sleep. In parallel, the constellation of adverse health outcomes associated with prolonged obesity, such as insulin resistance, elevated blood pressure, triglycerides, and reduced high-density lipoprotein cholesterol - termed metabolic syndrome -raises the risk of cardiovascular morbidity and mortality, type 2 diabetes, and all-cause mortality. Affecting 35-40% of U.S. adults, risk factors for metabolic syndrome, including obesity, middle age, sedentary behavior, and genetics, share considerable overlap with those for OSA. Thus, it has been difficult to disentangle cause, effect, and whether certain treatments, such as CPAP, can improve these outcomes. In this paper, we provide an update to our 2005 review which explored the association between OSA and metabolic syndrome, highlighting visceral obesity as the common etiological factor of both conditions. This update includes (a) recent data on physiological and biochemical mechanisms, (b) new data in nonobese men and women as well as children and adolescents, (c) insight from the latest treatment studies, (d) the role of aging in understanding clinically-meaningful phenotypes of the disorder, and (e) the potential diagnostic/prognostic utility of biomarkers in identifying OSA patients with the strongest cardiometabolic risk.

Adropin and Inflammation Biomarker Levels in Male Patients With Obstructive Sleep Apnea: A Link With Glucose Metabolism and Sleep Parameters

STUDY OBJECTIVES

The main objectives of the study were to determine plasma adropin, systemic inflammation biomarker levels, and glucose metabolism parameters in patients with moderate and severe obstructive sleep apnea (OSA) compared to healthy controls.

METHODS

In this study, we included 50 male patients with OSA (25 moderate and 25 severe) and 25 age- and sex-matched control subjects. All subjects underwent fasting sampling of peripheral blood for laboratory analyses.

RESULTS

Adropin plasma levels were significantly lower in the severe OSA group in comparison with the moderate and control groups (4.50 ± 1.45 versus 6.55 ± 1.68 versus 8.15 ± 1.79 ng/mL, P < .001). Plasma biomarkers of systemic inflammation were significantly increased in patients with moderate OSA (interleukin [IL]-6 and tumor necrosis factor alpha [TNF-α]) and severe OSA (IL-6, TNF-α, high-sensitivity C-reactive protein) when compared with controls (P < .001). Adropin levels showed a significant negative correlation with IL-6 (r = -.419, P < .001), TNF-α (r = -.540, P < .001), fasting glucose (r = -.331, P = .004), hemoglobin A1c (r = -.438, P < .001), homeostatic model assessment insulin resistance index (r = -.213, P = .046), and polysomnographic parameters including apnea-hypopnea index (r = -.615, P < .001) and oxygen desaturation index (r = -.573, P < .001). A multivariate regression analysis showed that plasma adropin remained as a significant negative predictor of severe OSA status, when adjusted for age and body mass index and computed along with other inflammatory biomarkers in the regression model (odds ratio 0.069, 95% confidence interval 0.009-0.517, P = .009).

CONCLUSIONS

Plasma adropin concentrations significantly correlate with indices of disease severity in patients with OSA, suggesting that adropin potentially plays an important role in the complex pathophysiology of the disease.

The Apnea-Hypopnea Index Underestimates Systemic Inflammation in Women with Sleep-Disordered Breathing

BACKGROUND

Evidence suggests that sleep-related respiratory and related metabolic compromise may vary between females and males with sleep-disordered breathing (SDB). Our purpose was to elucidate possible gender differences in sleep-associated respiratory and inflammatory parameters in patients with SDB.

MATERIALS AND METHODS

A consecutive number of SDB patients (46 females and 167 males) who underwent polysomnography were retrospectively reviewed. Fibrinogen and C-reactive protein (CRP) concentration, apnea index (ApnI), hypopnea index (HypI), apnea-hypopnea index (AHI), average and minimal SpO₂, duration of snoring, age, and body mass index (BMI) were compared between sexes. Spearman's ρ correlation coefficients between parameters were also calculated.

RESULTS

ApnI and AHI were significantly higher in males. Correlation analysis revealed striking gender differences: only in females, CRP concentration was highly correlated with snoring duration (r = 0.4393), BMI (r = 0.7147), minimal SpO₂ (r = -0.4357), and average SpO₂ (r = -0.4547); in females, HypI was more strongly correlated with AHI (r = 0.8778), average SpO₂ (r = -0.5765), minimal SpO₂ (r = -0.5817), and fibrinogen concentration (r = 0.4614) than in males (r = 0.4373; -0.3295; -0.2969; and 0.0887, respectively); in females, age had a much more pronounced effect on ApnI, HypI, AHI, average oxygen saturation (SaO₂), minimal SaO₂, snoring duration, and CRP and fibrinogen concentration.

CONCLUSIONS

Respiratory compromise in females with SDB is more strongly associated with systemic inflammation than in males with SDB. Although females display a pathological AHI less frequently than males, they reach quite similar pathological SaO₂, CRP, and fibrinogen values. Therefore, AHI may underestimate the pathophysiological systemic effects of SDB in females.

Determinants of sleepiness in obstructive sleep apnea

STUDY OBJECTIVES

Significant interindividual variability in sleepiness is observed in clinical populations with obstructive sleep apnea (OSA). This phenomenon is only partially explained by the apnea-hypopnea index (AHI). Understanding factors that lead to sleepiness is critical to effective management of patients with OSA. We examined demographic and other factors associated with sleepiness in OSA.

METHODS

Prospective study of 283 patients with newly diagnosed OSA by polysomnography (AHI ≥ 5 per hour). Subjective sleepiness (Epworth Sleep Scale [ESS] ≥ 11) and objective sleepiness (psychomotor vigilance task [PVT] mean lapse ≥ 2) were assessed.

RESULTS

Participants were classified into four groups (1: sleepy by ESS and PVT, 2: sleepy by PVT only, 3: sleepy by ESS only, and 4: nonsleepy reference group) and compared by generalized logit model. Shorter daily sleep duration by actigraphy and less morningness were associated with higher risk of sleepiness (Odds ratio [OR] = 0.52, 95% confidence interval [CI] 0.33-0.82 and OR = 0.89, CI 0.80-0.98, respectively). African-American race was associated with sleepiness (group 1, OR = 8.8, CI 2.8-27.3; group 2, OR = 16.6, CI 3.3-83.6; and group 3, OR = 3.3, CI 1.0-10.1). IL-6 level was higher in groups 1 and 3 (OR = 1.9, CI 1.0-3.4 and OR 2.0, CI 1.1-3.7, respectively).

CONCLUSIONS

African-American race, short sleep duration, chronotype, and increased proinflammatory cytokine IL-6 level were associated with sleepiness in OSA. These findings will inform future investigations determining mechanisms of sleepiness in OSA.

Use of blood biomarkers to screen for obstructive sleep apnea

PURPOSE

Obstructive sleep apnea (OSA) is a highly prevalent disorder associated with increased risk for cardiovascular disease, diabetes, and other chronic conditions. Unfortunately, up to 90% of individuals with OSA remain without a diagnosis or therapy. We assess the relationship between OSA and blood biomarkers, and test the hypothesis that combinations of markers provide a characteristic OSA signature with diagnostic screening value. This validation study was conducted in an independent cohort in order to replicate findings from a prior feasibility study.

PATIENTS AND METHODS

This multicenter prospective study consecutively enrolled adult male subjects with clinically suspected OSA. All subjects underwent overnight sleep studies. An asymptomatic control group was also obtained. Five biomarkers were tested: glycated hemoglobin (HbA1c), C-reactive protein (CRP), uric acid, erythropoietin (EPO), and interleukin-6 (IL-6).

RESULTS

The study enrolled 264 subjects. The combination of HbA1c+CRP+EPO (area under the curve 0.78) was superior to the Epworth Sleepiness Scale (ESS; 0.53) and STOP-Bang (0.70) questionnaires. In non-obese subjects, the combination of biomarkers (0.75) was superior to body mass index (BMI; 0.61). Sensitivity and specificity results, respectively, were: HbA1c+CRP+EPO (81% and 60%), ESS (78% and 19%), STOP-Bang (75% and 52%), BMI (81% and 56%), and BMI in non-obese patients (81% and 38%).

CONCLUSION

We verify our hypothesis and replicate our prior feasibility findings that OSA is associated with a characteristic signature cluster of biomarker changes in men. Concurrent elevations of HbA1c, CRP, and EPO levels should generate a high suspicion of OSA and may have utility as an OSA screening tool. Biomarker combinations correlate with OSA severity and, therefore, may assist sleep centers in identifying and triaging higher risk patients for sleep study diagnosis and treatment.

Evaluation of Inflammatory Markers in a Large Sample of Obstructive Sleep Apnea Patients without Comorbidities

Systemic inflammation is important in obstructive sleep apnea (OSA) pathophysiology and its comorbidity. We aimed to assess the levels of inflammatory biomarkers in a large sample of OSA patients and to investigate any correlation between these biomarkers with clinical and polysomnographic (PSG) parameters. This was a cross-sectional study in which 2983 patients who had undergone a polysomnography for OSA diagnosis were recruited. Patients with known comorbidities were excluded. Included patients (n = 1053) were grouped according to apnea-hypopnea index (AHI) as mild, moderate, and severe. Patients with AHI < 5 served as controls. Demographics, PSG data, and levels of high-sensitivity C-reactive protein (hs-CRP), fibrinogen, erythrocyte sedimentation rate (ESR), and uric acid (UA) were measured and compared between groups. A significant difference was found between groups in hs-CRP, fibrinogen, and UA. All biomarkers were independently associated with OSA severity and gender (p < 0.05). Females had increased levels of hs-CRP, fibrinogen, and ESR (p < 0.001) compared to men. In contrast, UA levels were higher in men (p < 0.001). Our results suggest that inflammatory markers significantly increase in patients with OSA without known comorbidities and correlate with OSA severity. These findings may have important implications regarding OSA diagnosis, monitoring, treatment, and prognosis. This trial is registered with ClinicalTrials.gov number NCT03070769.

Vitamin D deficiency and interleukin-17 relationship in severe obstructive sleep apnea-hypopnea syndrome

PURPOSE

We aimed to assess Vitamin D (VD) abnormalities in patients with severe obstructive sleep apnea-hypopnea syndrome (OSAHS), to study its association with clinical and polygraphic data, and to correlate VD levels with interleukin-17 (IL-17).

METHODS

Ninety-two patients with severe OSAHS were consecutively enrolled between September 2014 and February 2016 and compared to age-, sex-, and body mass index (BMI)-matched controls. Anthropometric parameters and medical history were collected. The serum levels of VD and IL-17 were determined by radioimmunoassay and enzyme-linked immunosorbent assay, respectively.

RESULTS

Ninety-two severe OSAHS patients and thirty controls were enrolled in the study. All OSAHS patients had VD deficiency. The mean level of VD was at 7.9 ng/ml among OSAHS group versus 16.8 ng/ml among control group. IL-17A levels were elevated (20.3 pg/ml) in OSAHS group compared to healthy group (10.05 pg/ml). VD levels were negatively correlated with nocturia severity (r = -0.26; P = 0.01) and positively correlated with mean O₂ saturation (r = 0.59; P = 0.02) and lowest O₂ saturation (r = 0.3; P = 0.03). IL-17 levels were positively correlated with nocturia severity (r = 0.24; P = 0.03) and negatively correlated with mean O₂ saturation (r = -0.42; P = 0.03). A significant negative association was observed between IL-7 and VD levels (r = -0.64, P = 0.2 10^-4). The magnitude of this correlation was higher for important nocturia, lower MSaO₂, or higher BMI.

CONCLUSIONS

VD deficiency in patients with severe OSAHS is common with a negative association between IL-17 and VD serum levels. Hypoxia could play an important role in this association. Further studies are needed to clarify this relationship.