Selective Activation of Inflammatory Pathways by Intermittent Hypoxia in Obstructive Sleep Apnea Syndrome

Inflammatory and Redox Blood Gene Expression Fingerprint of Severe Obstructive Sleep Apnoea in Patients With Mild Alzheimer's Disease

Introduction

Obstructive sleep apnoea (OSA) is the sleep disorder most frequently found in patients with Alzheimer's disease (AD). The intermittent hypoxia (IH) caused by OSA may participate in AD pathogenesis through increase in oxidative damage and inflammation. We aimed to identify inflammatory and redox genes differentially expressed in the blood from AD patients with severe OSA compared with those with nonsevere OSA.

Methods

We included 40 AD patients diagnosed based on clinical manifestations and AD biomarker levels in cerebrospinal fluid (CSF). Severe or nonsevere OSA (apnoea-hypopnea index ≥ 30/h and < 30/h, respectively) was diagnosed through overnight polysomnography (PSG). The expression levels of 136 inflammation-related and 84 redox-related genes were evaluated by whole blood targeted transcriptomics.

Results

Three inflammatory and six redox genes were upregulated in the blood of AD patients with severe OSA. Three of them correlated with PSG parameters. A pathway enrichment analysis showed a strong enrichment of the serotonergic synapse pathway in severe OSA AD patients.

Discussion

Our results show an upregulation of nine genes involved in NF-κB-mediated inflammation and redox metabolism in the blood of patients with mild AD with severe OSA. Therefore, severe OSA may worsen the inflammation and oxidative damage that are already altered in patients with AD.

Airway morphology, hyoid position, and serum inflammatory markers of obstructive sleep apnea in children treated with modified twin-block appliances

OBJECTIVE

To investigate the effects of modified twin-block appliances (MTBA) on obstructive sleep apnea (OSA) and mandibular retrognathia and the changes in the upper airway, hyoid bone position, and hypoxia-related inflammatory marker levels in children with OSA.

METHODS

This study included children with OSA and mandibular retrognathia and those with class I without mandibular retrognathia (n = 35 each). The experimental group comprised children with OSA and mandibular retrognathia managed using MTBA. Postoperative and preoperative polysomnography, lateral cephalometric radiographs, and peripheral blood samples were collected. The control group comprised children with class I without mandibular retrognathia.

RESULTS

Following MTBA management, the experimental group exhibited decreased apnea-hypopnea index and increased lowest arterial oxygen saturation level (P < 0.05). Sella- and subspinale-nasion-supramental angles significantly increased and decreased, respectively (P < 0.05). Posterior soft palatal-posterior pharyngeal wall distance, apical palatal-middle pharyngeal wall distance, posterior airway space, epiglottis valley-hypopharyngeal wall distance, hyoid-prevertebral plane distance, and distance from the superior anterior point of the hyoid bone to the inferior anterior point of the third cervical spine significantly increased, whereas distance from the superior anterior point of the hyoid bone to the mandibular plane decreased (P < 0.05).

CONCLUSIONS

Children with OSA (n = 35) were managed using MTBA, which relieved the mandibular retrognathia deformity, widened the upper airway space, moved the hyoid bone forward and upward, and improved the sleep monitoring indicators. Thus, MTBA can achieve satisfactory therapeutic effect in children with OSA and mandibular retrognathia with mandibular advancement.

Sustained hypoxia but not intermittent hypoxia induces HIF-1α transcriptional response in human aortic endothelial cells

Obstructive sleep apnea (OSA) is characterized by intermittent hypoxic environments at the cellular level and is an independent risk factor for the development of cardiovascular disease. Endothelial cell (EC) dysfunction precedes the development of cardiovascular disease; however, the mechanisms by which ECs respond to these intermittent hypoxic events are poorly understood. To better understand EC responses to hypoxia, we examined the effects of sustained hypoxia (SH) and intermittent hypoxia (IH) on the activation of HIF-1α in ECs. While SH stabilized HIF-1α and led to its nuclear localization, IH did not activate HIF-1α and the expression of its target genes. Using RNA-sequencing, we evaluated transcriptional responses of ECs to hypoxia. SH induced the expression of HIF-1α and hypoxia response genes, while IH affected cell-cycle regulation genes. A cytoscape protein-protein interaction network for EC response to hypoxia was created with differentially expressed genes. The network comprises cell-cycle regulation, inflammatory signaling via NF-κB and response to VEGF stimulus subnetworks on which SH and IH had distinct activities. As OSA is associated with elevated catecholamines, we investigated the effect of epinephrine on the EC response to SH and IH. Transcriptomic responses under IH and epinephrine revealed protein-protein interaction networks emphasizing distinct subnetworks, including cytokine-mediated TNFα signaling via NF-κB, Wnt/LRP/DKK signaling and cell cycle regulation. This study reveals differential transcriptomic responses under SH and IH characterised by HIF-1α transcriptional response induced only by SH, but not by IH. The study also features the potential molecular events that may occur at the vascular level in OSA.

Co-targeting of glial activation and inflammation by tsRNA-Gln-i-0095 for treating retinal ischemic pathologies

Ischemic retinopathies are the major causes of blindness, yet effective early-stage treatments remain limited due to an incomplete understanding of the underlying molecular mechanisms. Significant changes in gene expression often precede structural and functional alterations. Transfer RNA (tRNA)-derived small RNAs (tsRNAs) are emerging as novel gene regulators, involved in various biological processes and human diseases. In this study, tsRNA-Gln-i-0095 was identified as a novel regulator, which was significantly upregulated in retinal ischemia/reperfusion (I/R) injury. Reducing the levels of tsRNA-Gln-i-0095 suppressed reactive gliosis, lowered inflammatory cytokine levels, and protected retinal ganglion cells from I/R injury. These effects led to reduced structural and functional damage, inhibited glial activation and inflammation, and enhanced neuronal function. Mechanistically, tsRNA-Gln-i-0095 downregulated the expression of NFIA and TGFBR2 through a miRNA-like mechanism. Collectively, this study highlights the potential of targeting tsRNA-Gln-i-0095 as a novel therapeutic approach to reduce retinal I/R injury and preserve visual function.

Evaluation of Choroidal Thickness and Retinal Vessel Density with Serum HIF-1α and TNF-α Level in Patients with OSAS

PURPOSE

To reveal changes in choroidal thickness, retinal vessel density, and serum HIF-1α and TNF-α levels in obstructive sleep apnea syndrome (OSAS) and their correlation.

METHODS

This prospective case-control study included 118 patients divided into mild-to-moderate OSAS (n = 40), severe OSAS (n = 39), and a control group (n = 39). Choroidal thickness was evaluated with OCT, vessel density with OCTA, AHI index with polysomnography, and serum HIF-1α and TNF-α levels were analyzed using the enzyme-linked immunosorbent assay.

RESULTS

The serum HIF-1α values of the participants in the mild-moderate OSAS and severe OSAS groups were [893.25(406.7-2068) and 1027(453-2527), respectively], and were both significantly higher than the control group [(521.5(231.6-2741))] (p < 0.001). Serum TNF-α levels did not differ significantly between the groups (p = 0.051).). Subfoveal choroidal thickness (SFCT) values of the severe OSAS groups were significantly lower than the control group (p < 0.05). The superficial and deep capillary plexus vascular density (SVD and DVD) values of the severe OSAS group were lower than the control group (p < 0.05). Serum HIF-1α and TNF-α levels of all participants were negatively correlated with both their SVD values (p < 0.05, r: -0.220 and p < 0.05, r: -0.252, respectively) and their DVD values (p < 0.001, r: -0.324 and p = 0.001, r: -0.299, respectively).

CONCLUSIONS

Increased serum levels of inflammatory mediators (HIF-1α ve TNF-α) in OSAS cause a decrease in SFCT, SVD, and DVD, which is an indication of systemic vascular damage. Further research on developing treatment strategies to modulate TNF-α ve HIF-1α may help recede vascular morbidity in OSAS patients.

Body Mass Index mediates the associations between dietary approaches to stop hypertension and obstructive sleep apnea among U.S. adults

Background

The Dietary Approaches to Stop Hypertension (DASH) are associated with reduced cardiovascular, diabetes risk, but the effect on obstructive sleep apnea (OSA) is uncertain.

Methods

This study used data from the National Health and Nutrition Examination Survey (NHANES). DASH score was assessed through 24-h dietary recall interviews, and OSA diagnosis in individuals was based on predefined criteria. Logistic regression analysis was used to assess the association between DASH and OSA. Restricted cubic spline (RCS) analysis was used to investigate the dose-response relationship between DASH score and OSA risk. And comprehensive subgroup and mediation analyses were performed.

Results

Among the 14,978 participants, 27.01% had OSA. DASH scores had a negative association with the risk of OSA (OR = 0.91, 95%CI: 0.88-0.95, p < 0.01). Next, we divided DASH scores into quintiles groups. In comparison to the reference group Q1, groups Q5 had adjusted OR values of 0.63 (95%CI: 0.52-0.76, p < 0.01). Subgroup analyses revealed that this association was consistent across different groups. Further mediation analyses showed that the associations of DASH with OSA risk parallelly mediated by the above Body Mass Index (BMI) 33.4%,95%CI (20.6-46.2%) (all p < 0.05). The restricted cubic spline (RCS) analysis indicated a significant dose-response relationship between DASH diet and OSA risk.

Conclusion

These findings suggested that DASH decreased OSA risk, which was possibly and partly mediated by BMI.

The Association of Obstructive Sleep Apnea with Urological Cancer Incidence and Mortality-A Systematic Review and Meta-analysis

BACKGROUND AND OBJECTIVE

While obstructive sleep apnea (OSA) and urological cancer are both strongly associated with hypoxia, controversy exists regarding their association with each other. This study aims to summarize and synthesize evidence to clarify the association between OSA and urological cancer incidence and mortality.

METHODS

According to a prespecified protocol, PubMed, Embase, Cochrane Library, and Scopus were searched from inception to November 16, 2023, for observational and randomized studies reporting the association of OSA with urological cancer incidence or mortality. We pooled maximally covariate-adjusted hazard ratios (HRs) using a random-effects inverse variance-weighted model. Two reviewers independently assessed the quality of evidence using the Newcastle-Ottawa Scale and the Grading of Recommendations, Assessment, Development and Evaluation framework.

KEY FINDINGS AND LIMITATIONS

From 1814 records, we included 12 studies comprising 9 290 818 participants in total, of which nine studies were analyzed quantitatively. OSA patients had an increased risk of kidney (HR: 1.75, 95% confidence interval [CI]: 1.21-2.53) and bladder (HR: 1.76, 95% CI: 1.05-2.96) cancer. However, OSA was not associated with prostate cancer incidence (HR: 1.29, 95% CI: 0.82-2.04). We systematically reviewed evidence surrounding OSA and testicular cancer incidence and urological cancer mortality.

CONCLUSIONS AND CLINICAL IMPLICATIONS

OSA may be associated with a higher risk of kidney and bladder cancer, but not prostate cancer. Future work may help clarify the possibility of a dose-response relationship between OSA and urological cancer, and the effect of OSA treatment on urological cancer incidence or progression.

PATIENT SUMMARY

This research highlights a potential longitudinal association between OSA and kidney and bladder cancer, but not prostate cancer.

Effect of continuous positive airway pressure therapy on blood levels of IL-6, IL-10, IL-18, IL-1β, IL-4, and IL-17 in obstructive sleep apnoea adults: A systematic review, meta-analysis and trial sequential analysis

INTRODUCTION

Obstructive sleep apnoea (OSA) is a long-term disorder characterized by frequent blockages in the upper respiratory tract during sleep, often leading to abrupt awakenings, with or without a decrease in oxygen levels. The systematic review and meta-analysis aimed to assess the effect of continuous positive airway pressure therapy (CPAP) on blood interleukin (IL) levels of IL-6, IL-10, IL-18, IL-1β, IL-4, and IL-17 in OSA adults.

MATERIALS AND METHODS

The published databases from PubMed, Scopus, Web of Science, and Cochrane Library were searched from 2003 to 2024, without any restrictions. The Review Manager software 5.3 was employed to compute effect sizes, which were presented as the standardized mean difference (SMD) along with a 95% confidence interval (CI).

RESULTS

In total, 320 records were identified through database searching; ultimately, 42 articles were included in the qualitative synthesis and then the meta-analysis. The CPAP therapy significantly reduces IL-6 levels, as indicated SMD=0.64 [95% CI: 0.35, 0.93] and P<0.0001. CPAP therapy significantly reduced IL-18 and IL-1β levels in adults with OSA, but there is no significant difference in IL-10, IL-4, or IL-17 levels. Age, blood sample, body mass index, ethnicity, and treatment duration for IL-6 and apnoea-hypopnea index with IL-10 levels were effective factors in the pooled results. Experimentally, there was an interaction between IL-18 and IL-1β.

CONCLUSIONS

CPAP therapy has a positive impact on inflammatory markers in OSA adults; remarkably, it reduces IL-6 and IL-1β levels. Nevertheless, more evidence (such as the role of ethnicity) and understanding of interactions are needed.

Associations Among Cardiometabolic Risk Factors, Sleep Duration, and Obstructive Sleep Apnea in a Southeastern US Rural Community: Cross-Sectional Analysis From the SLUMBRx-PONS Study

BACKGROUND

Short sleep and obstructive sleep apnea are underrecognized strains on the public health infrastructure. In the United States, over 35% of adults report short sleep and more than 80% of individuals with obstructive sleep apnea remain undiagnosed. The associations between inadequate sleep and cardiometabolic disease risk factors have garnered increased attention. However, challenges persist in modeling sleep-associated cardiometabolic disease risk factors.

OBJECTIVE

This study aimed to report early findings from the Short Sleep Undermines Cardiometabolic Health-Public Health Observational study (SLUMBRx-PONS).

METHODS

Data for the SLUMBRx-PONS study were collected cross-sectionally and longitudinally from a nonclinical, rural community sample (n=47) in the southeast United States. Measures included 7 consecutive nights of wrist-based actigraphy (eg, mean of 7 consecutive nights of total sleep time [TST7N]), 1 night of sleep apnea home testing (eg, apnea-hypopnea index [AHI]), and a cross-sectional clinical sample of anthropometric (eg, BMI), cardiovascular (eg, blood pressure), and blood-based biomarkers (eg, triglycerides and glucose). Correlational analyses and regression models assessed the relationships between the cardiometabolic disease risk factors and the sleep indices (eg, TST7N and AHI). Linear regression models were constructed to examine associations between significant cardiometabolic indices of TST7N (model 1) and AHI (model 2).

RESULTS

Correlational assessment in model 1 identified significant associations between TST7N and AHI (r=-0.45, P=.004), BMI (r=-0.38, P=.02), systolic blood pressure (r=0.40, P=.01), and diastolic blood pressure (r=0.32, P=.049). Pertaining to model 1, composite measures of AHI, BMI, systolic blood pressure, and diastolic blood pressure accounted for 25.1% of the variance in TST7N (R2adjusted=0.25; F2,38=7.37; P=.002). Correlational analyses in model 2 revealed significant relationships between AHI and TST7N (r=-0.45, P<.001), BMI (r=0.71, P<.001), triglycerides (r=0.36, P=.03), and glucose (r=0.34, P=.04). Results from model 2 found that TST7N, triglycerides, and glucose accounted for 37.6% of the variance in the composite measure of AHI and BMI (R2adjusted=0.38; F3,38=8.63; P<.001).

CONCLUSIONS

Results from the SLUMBRx-PONS study highlight the complex interplay between sleep-associated risk factors for cardiometabolic disease. Early findings underscore the need for further investigations incorporating the collection of clinical, epidemiological, and ambulatory measures to inform public health, health promotion, and health education interventions addressing the cardiometabolic consequences of inadequate sleep.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

RR2-10.2196/27139.

Influence of sleep on physiological systems in atherosclerosis

Sleep is a fundamental requirement of life and is integral to health. Deviation from optimal sleep associates with numerous diseases including those of the cardiovascular system. Studies, spanning animal models to humans, show that insufficient, disrupted or inconsistent sleep contribute to poor cardiovascular health by disrupting body systems. Fundamental experiments have begun to uncover the molecular and cellular links between sleep and heart health while large-scale human studies have associated sleep with cardiovascular outcomes in diverse populations. Here, we review preclinical and clinical findings that demonstrate how sleep influences the autonomic nervous, metabolic and immune systems to affect atherosclerotic cardiovascular disease.

Link Between Obstructive Sleep Apnea and Kidney Stones: NHANES 2015-2018 and Mendelian Randomization

Purpose

The prevalence of Obstructive Sleep Apnea (OSA) is high, and there are many complications. Few studies have reported the relationship between OSA and kidney stones. The purpose of this study is to explore whether people at risk of OSA will increase the risk of kidney stones.

Methods

This was a cross-sectional study, and information was collected through the National Health and Nutrition Examination Survey conducted from 2015 to 2018. Multiple logistic regression analyses were employed to calculate the odds ratios (ORs) and their 95% confidence intervals (CIs) for the link between obstructive sleep apnea and the presence of kidney stones. Additionally, to assess causality and reduce observational biases, five distinct two-sample Mendelian randomization techniques were applied.

Results

Following the adjustment for relevant confounders, findings indicated a statistically significant correlation between obstructive sleep apnea (OSA) and higher prevalence of kidney stones (OR = 1.29; 95% CI: 1.00-1.66). Additionally, using the inverse-variance weighted approach in Mendelian randomization, results suggested a genetic predisposition to OSA might be causally linked to an elevated risk of developing kidney stones (OR: 1.00221, 95% CI 1.00056-1.00387).

Conclusion

OSA promotes the formation of kidney stones, and the treatment and management of OSA can improve or mitigate the occurrence of kidney stones.

Sleep disorders in chronic kidney disease

Sleep disorders are highly prevalent in chronic kidney disease (CKD) but are often under-recognized. Restless legs syndrome, which is common in CKD owing to issues with dopamine metabolism and is exacerbated by iron deficiency and uraemia, can lead to poor sleep quality and increased daytime fatigue. Insomnia is also prevalent in CKD, particularly in patients requiring dialysis, with increased sleep latency and sleep fragmentation being reported. The cause of insomnia in CKD is multifactorial - poor sleep habits and frequent napping during dialysis, uraemia, medications and mood disorders have all been suggested as potential contributing factors. Sleep apnoea and CKD are also now recognized as having a bi-directional relationship. Sleep apnoea is a risk factor for accelerated progression of CKD, and fluid overload, which is associated with kidney failure, can lead to both obstructive and central sleep apnoea. The presence of obstructive sleep apnoea in CKD can exacerbate the already heightened cardiovascular morbidity and mortality in these patients, as well as leading to daytime fatigue and reduced quality of life. Increased awareness, timely diagnosis and appropriate therapeutic interventions are essential to reduce the negative impact of sleep disorders in patients with kidney disease.

Interactions of Obstructive Sleep Apnea With the Pathophysiology of Cardiovascular Disease, Part 1: JACC State-of-the-Art Review

The American Heart Association considers sleep health an essential component of cardiovascular health, and sleep is generally a time of cardiovascular quiescence, such that any deviation from normal sleep may be associated with adverse cardiovascular consequences. Many studies have shown that both impaired quantity and quality of sleep, particularly with obstructive sleep apnea (OSA) and comorbid sleep disorders, are associated with incident cardiometabolic consequences. OSA is associated with repetitive episodes of altered blood gases, arousals, large negative swings in intrathoracic pressures, and increased sympathetic activity. Recent studies show that OSA is also associated with altered gut microbiota, which could contribute to increased risk of cardiovascular disease. OSA has been associated with hypertension, atrial fibrillation, heart failure, coronary artery disease, stroke, and excess cardiovascular mortality. Association of OSA with chronic obstructive lung disease (overlap syndrome) and morbid obesity (obesity hypoventilation syndrome) increases the odds of mortality.

TRPC5-mediated NLRP3 inflammasome activation contributes to myocardial cell pyroptosis in chronic intermittent hypoxia rats

BACKGROUND

Chronic intermittent hypoxia (CIH) is the primary cause of myocardial inflammation in obstructive sleep apnea-hypopnea syndrome (OSAHS). Pyroptosis is a newly discovered form of programmed cell death accompanying inflammatory reactions. Our previous study showed that TRPC5 is upregulated in the myocardial injury of CIH rats. The present study aimed to explore the role of TRPC5 in CIH-induced myocardial cell pyroptosis.

METHODS

A model of CIH in OSA rats was established. SD rats were randomly divided into control group(8rats) and OSA group(8rats). Scanning electron microscope(SEM) was performed on left ventricular tissues slides. Western blot were used to detect the expression levels of pyroptosis-related factors and TRPC5 and its downstream proteins in myocardia tissue.

RESULTS

The pyroptosis of myocardial cells by SEM revealed damaged cell membrane integrity of OSA group rats, with fibrous tissue attached to the cell membrane surface, and vesicular protrusions and pyroptotic bodies were observed. Compared to the control group, the expression of pyroptosis-related proteins, such as caspase1, pro-IL-1β, IL-1β, IL-18, GSDMD, and GSDMD-N was upregulated in the OSA group (p < 0.05). Compared to the control group, the expression of TRPC5, NLPR3, p-CaMKIIβ + δ+γ, and HDAC4 was higher in the OSA group (p < 0.05).

CONCLUSIONS

These findings indicated that the pyroptosis response increases in CIH-induced myocardial injury, and the mechanism that TRPC5 is upregulated, promoting the expression of NLRP3 and inflammasome formation through CaMKII phosphorylation and HDAC4 cytoplasmic translocation. This might be a potential target for the treatment of OSA-induced myocardial injury.

Is there a relationship between the severity of obstructive sleep apnea syndrome and the systemic immune inflammation index?

AIM

Vascular dysfunction, oxidative stress and systemic inflammation are considered responsible for the pathophysiology of Obstructive sleep apnea syndrome (OSAS). It is thought that desaturation due to apnea-hypopnea attacks in OSAS patients activates inflammatory pathways. In this study, we aimed to reveal the relationship between inflammation parameters Systemic immune inflammation index (SII), neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratios (PLR) severity of OSAS in patients who underwent polysomnography in our hospital's sleep laboratory.

METHODS

We grouped our 171 patients who were followed up in our sleep laboratory with the diagnosis of OSAS according to their AHI values. We evaluated the correlation of SII, NLR, and PLR values obtained from the complete blood tests of our patients with OSAS diagnosis and OSAS severity.

RESULTS

The mean NLR, PLR and SII values of patients with OSAS were statistically significantly higher than those without OSAS (p < 0.05). A positive correlation of 18% was found between the presence of OSAS and the SII value (p = 0.016). No statistically significant difference was found when comparing OSAS severity and NLR, PLR and SII values (p > 0.05).

CONCLUSION

We observed that SII, NLR and PLR parameters, which are rapidly assessable systemic inflammation markers of this process, were independently associated in patients diagnosed with OSAS and that there was no change in SII, NLR, and PLR parameters with OSAS severity.

Morning headache caused by obstructive sleep apnea misdiagnosed as temporomandibular disorders-related headache: A case report

PATIENT

A 67-year-old woman presented to our clinic with chief complaints of headache and mandibular heaviness. Physical examination revealed bilateral tenderness in the temporalis and masseter muscles, corresponding to the patient's chief complaint. Thus, a diagnosis of temporomandibular disorders (TMDs)-related headache was made. However, sleep disorders were identified after further consultation. Hence, sleep apnea-related headache was suspected due to a snoring habit with a Mallampati classification of Class IV. Out-of-center sleep testing (OCST) revealed a respiratory event index (REI) of 10.1/h and a low peripheral oxygen saturation (SpO2) of 76%. Consequently, a diagnosis of obstructive sleep apnea (OSA) was made, and treatment using the mandibular advancement device (MAD) was recommended. Following MAD treatment, the patient's sleep quality improved, and morning headaches ceased. Subsequent OCST performed while wearing the MAD showed a significant reduction in the REI to 1.6/h and an increase in the SpO2 to 86%, indicating the therapeutic efficacy of the MAD in treating OSA.

DISCUSSION

MAD treatment effectively alleviated the patient's morning headaches, suggesting that sleep bruxism should not be considered the only cause of headaches. OSA should also be considered and addressed when investigating the potential causes of morning headaches in patients.

CONCLUSIONS

In patients experiencing TMDs symptoms and morning headaches, TMDs should not be presumed as the sole cause. Dentists should discuss the likelihood of sleep disorders during consultations. If sleep disorders are suspected, the possibility of OSA should be considered, and sleep tests should be conducted when necessary.

Association of Obstructive Sleep Apnea with Nonalcoholic Fatty Liver Disease: Evidence, Mechanism, and Treatment

Obstructive sleep apnea (OSA), a common sleep-disordered breathing condition, is characterized by intermittent hypoxia (IH) and sleep fragmentation and has been implicated in the pathogenesis and severity of nonalcoholic fatty liver disease (NAFLD). Abnormal molecular changes mediated by IH, such as high expression of hypoxia-inducible factors, are reportedly involved in abnormal pathophysiological states, including insulin resistance, abnormal lipid metabolism, cell death, and inflammation, which mediate the development of NAFLD. However, the relationship between IH and NAFLD remains to be fully elucidated. In this review, we discuss the clinical correlation between OSA and NAFLD, focusing on the molecular mechanisms of IH in NAFLD progression. We meticulously summarize clinical studies evaluating the therapeutic efficacy of continuous positive airway pressure treatment for NAFLD in OSA. Additionally, we compile potential molecular biomarkers for the co-occurrence of OSA and NAFLD. Finally, we discuss the current research progress and challenges in the field of OSA and NAFLD and propose future directions and prospects.

Impact of Obstructive Sleep Apnea and Sympathetic Nervous System on Cardiac Health: A Comprehensive Review

A prevalent condition linked to an elevated risk of cardiovascular disease is sleep apnea. This review examines the connections between cardiac risk, the sympathetic nervous system, and sleep apnea. The increased risk of hypertension, arrhythmias, myocardial infarction, and heart failure was highlighted in the pathophysiology of sleep apnea and its effect on sympathetic activation. It is also important to consider potential processes such as oxidative stress, inflammation, endothelial dysfunction, and autonomic imbalance that may relate sleep apnea-induced sympathetic activation to cardiac risk. With implications for creating innovative diagnostic and treatment approaches to lessen the cardiovascular effects of sleep apnea, the goal of this investigation is to improve the understanding of the intricate link between sympathetic activity, cardiac risk, and sleep apnea. This study aimed to clarify the complex relationship between cardiovascular health and sleep apnea by synthesizing the available research and highlighting the crucial role played by the sympathetic nervous system in moderating this relationship. Our thorough investigation may have important therapeutic ramifications that will direct the creation of focused therapies to enhance cardiovascular outcomes in sleep apnea sufferers.

Intermittent hypoxia induces Th17/Treg imbalance in a murine model of obstructive sleep apnea

Obstructive sleep apnea (OSA) is characterized by cyclic normoxic and hypoxic conditions (intermittent hypoxia, IH) induced by the repeated closure of the upper-airway respiratory tract. As a pathomechanism of OSA, IH results in various comorbidities via chronic inflammation and related pathways. However, the role of other inflammatory cells, such as lymphocytes, has not been well-explored. This study aimed to examine the effects of IH on the distribution and balance of T cell subsets and other related cytokines, and mechanisms in the immune system. We modified OSA mouse model (male C57BL/6N male) using our customized chamber that controls specific sleep and oxygenic cycles. To induce hypoxia, the IH group was repeatedly exposed to 5% O2 and 21% O2 lasting for 120 s each for 7 h daily for 4 weeks. Mice were then subjected to a recovery period of 4 weeks, in which IH stimulation was ceased. T cells and related cytokines were analyzed using flow cytometry and immunohistochemistry. Compared with the control group, the IH group had significantly lower levels of CD4+CD25+Foxp3+ regulatory T cells but higher levels of Th 17, IL-4, HIF-1, and inflammatory cytokines. After the recovery period, these altered changes in the immune cells were recovered, and we found no significant difference in their levels between the control and recovery groups. This study revealed that the Th17/Treg ratio is increased by intermittent hypoxia, and this imbalance can explain immune-related diseases, including recently reported allergies, autoimmune, and even cancer diseases, arising from OSA.

Obstructive Sleep Apnea as a Key Contributor to Mental Stress-Induced Myocardial Ischemia in Female Angina Patients with No Obstructive Coronary Artery Disease

Purpose

Mental stress induced myocardial ischemia (MSIMI) is regarded as the primary cause of the angina with no obstructive coronary artery disease (ANOCA). Obstructive sleep apnea (OSA) is autonomously linked to obstructive coronary heart disease, hypertension, and sudden cardiac death. Similar to the impact of psychological stress on the cardiovascular system, individuals with OSA experience periodic nocturnal hypoxia, resulting in the activation of systemic inflammation, oxidative stress, endothelial dysfunction, and sympathetic hyperactivity. The contribution of OSA to MSIMI in ANOCA patients is unclear. To explore the prevalence of OSA in ANOCA patients and the correlation between OSA and MSIMI, a prospective cohort of female ANOCA patients was recruited.

Patients and Methods

We recruited female patients aged 18 to 75 years old with ANOCA and evaluated MSIMI using positron emission tomography-computed tomography. Subsequently, Level III portable monitors was performed to compare the relationship between OSA and MSIMI.

Results

There is higher REI (7.8 vs 2.6, P=0.019), ODI (4.7 vs 9.2, P=0.028) and percentage of OSA (67.74% vs 33.33%, P=0.004) in MSIMI patients. The patients diagnosed with OSA demonstrated higher myocardial perfusion imaging scores (SSS: 1.5 vs 3, P = 0.005, SDS: 1 vs 3, P = 0.007). Adjusted covariates, the risk of developing MSIMI remained 3.6 times higher in OSA patients (β=1.226, OR = 3.408 (1.200-9.681), P = 0.021).

Conclusion

Patients with MSIMI exhibit a greater prevalence of OSA. Furthermore, the myocardial blood flow perfusion in patients with OSA is reduced during mental stress.

Implications of obstructive sleep apnea on reproductive health: a study on anti-Mullerian hormone levels

PURPOSE

This study aimed to explore the association between anti-mullerian hormone (AMH) levels and obstructive sleep apnea (OSA) severity.

METHODS

A cross-sectional design was employed to evaluate AMH levels in 68 premenopausal women diagnosed with OSA at Van Yüzüncü Yıl University Faculty of Medicine. OSA severity was scored according to the 2018 AASM guidelines using a 16-channel Embla device. AMH levels were measured from blood samples using a commercially available kit.

RESULTS

The study found that AMH levels in OSA patients were significantly lower than those in the healthy control group. A statistically significant negative correlation between AMH and AHI levels was observed. When stratified by OSA severity, the lowest AMH levels were found in the severe OSA group.

CONCLUSION

OSA may have potential endocrine implications, especially concerning reproductive health. Decreased AMH levels in OSA patients could indicate future risks of infertility or early menopause.

Does Obstructive Sleep Apnea Lead to Progression of Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD) and obstructive sleep apnea (OSA) have important bidirectional relationships that influence the pathophysiology of each disorder. The slim hyperinflated "pink puffer" phenotype of COPD protects against OSA, whereas the heavier "blue bloater" phenotype predisposes to OSA by fluid retention. OSA may aggravate COPD by promoting airway inflammation. COPD-OSA overlap patients have lower quality of life and are at higher risk of cardiovascular comorbidity than either disorder alone due to greater nocturnal oxygen desaturation and sympathetic activation. Management of OSA with positive airway pressure improves COPD outcomes that include lower exacerbation rates compared to untreated patients.

Rapid eye movement dependency is associated with increased inflammatory activity in obstructive sleep apnea syndrome

OBJECTIVE

Rapid eye movement (REM)-dependent obstructive sleep apnea syndrome (OSAS) is a specific subtype of OSAS having some phenotypic characteristics like a preference for a younger age, female gender, and milder severity. Such favorable features could make it possible to consider an overall benign course for this phenotype. However, accumulating data introduced its association with several cardiometabolic and vascular disorders recently. The primary objective of this study was to address the disease from the inflammation perspective and evaluate the potential inflammatory status in this variant via two accessible blood parameters: platelet distribution width (PDW) and systemic immune-inflammation index (SII). The secondary aim was to investigate whether this status, together with other disease characteristics, demonstrates consistency under different definitions of REM-dependent OSAS published previously.

PATIENTS AND METHODS

The medical records of 35 patients with mild-to-moderate REM-dependent OSAS, 35 age- and sex-matched patients with REM-independent OSAS, and 25 non-OSA controls were retrospectively analyzed. Baseline features, polysomnographic characteristics, PDW, and SII were compared between the groups. Secondly, the analyses were repeated using different definitions of REM-dependent OSAS. Bivariate analyses were performed, and a multiple stepwise regression model was applied to adjust for body mass index (BMI) and cardiovascular risk (CVR) factors.  RESULTS: Mean PDW and SII were increased in patients with REM-dependent OSAS as compared to non-OSA controls (p = .022 and .029). The significance remained stable after adjustment for BMI and CVRs and was consistent according to different definitions. The Comparison of patients with REM-independent OSAS and non-OSA controls, as well as the two different subtypes of OSAS, did not yield significance.

CONCLUSION

Based on the current findings, patients with REM-dependent OSAS appear to be susceptible to inflammation and should be carefully monitored for the negative consequences of that issue. To our knowledge, this study is the first to evaluate SII and PDW in REM-dependent OSAS.

Sleep disordered breathing: OSA-COPD overlap

INTRODUCTION

Sleep has important effects on breathing and gas exchange that may have negative consequences in patients with chronic obstructive pulmonary disease (COPD). COPD and obstructive sleep apnea (OSA) are highly prevalent and may coexist, which is referred to as the overlap syndrome.

AREAS COVERED

The probability of OSA-COPD overlap represents the balance of protective and promoting factors such as hyperinflation and fluid retention; thus, different clinical COPD phenotypes influence the likelihood of comorbid OSA. The clinical presentation of OSA-COPD overlap is nonspecific, and the diagnosis requires clinical awareness to identify patients needing overnight studies. Both COPD and OSA are associated with a range of overlapping physiological and biological disturbances including hypoxia and inflammation that contribute to cardiovascular comorbidities. The management of OSA-COPD overlap patients differs from those with COPD alone and the survival of overlap patients treated with positive airway pressure (PAP) is superior to those untreated.

EXPERT OPINION

The recognition of OSA-COPD overlap has important clinical relevance because of its impact on outcomes and management. Management of the overlap should address both sleep quality and disordered gas exchange. PAP therapy has demonstrated reductions in COPD exacerbations, hospitalizations, healthcare costs and mortality in overlap patients.

The Effects of Obstructive Sleep Apnea on the Cardiovascular System: A Comprehensive Review

Obstructive sleep apnea (OSA) is an increasingly relevant cause of cardiovascular morbidity worldwide. Although the association between OSA and the cardiovascular system is well-known, the extent of its effects is still a topic of interest, including pathophysiologic mechanisms, cardiovascular sequelae, and OSA therapies and their effects. Commonly described mechanisms of cardiovascular etiologies revolve around sympathetic activation, inflammation, and intermittent hypoxia resulting from OSA. Ultimately, these effects lead to manifestations in the cardiovascular system, such as arrhythmias, hypertension, and heart failure, among others. The resulting sequelae of OSA may also have differential effects based on gender and age; several studies suggest female gender to have more susceptibility to cardiovascular mortality, as well as an increase in age. Furthermore, several therapies for OSA, both established and emerging, show a reduction in cardiovascular morbidity and may even reduce cardiovascular burden. Namely, the establishment of CPAP has led to improvement in hypertension and cardiac function in patients with heart failure and even reduced the progression of early stages of atherosclerosis. Effective management of OSA decreases abnormal neural sympathetic activity, which results in better rhythm control and blood pressure control, both in waking and sleep cycles. With newer therapies for OSA, its effects on the cardiovascular system may be significantly reduced or even reversed after long-term management. The vast extent of OSA on the cardiovascular system, as well as current and future therapeutic strategies, will be described in detail in this review.

Pharmacological Activities of Plant-Derived Fraxin with Molecular Mechanisms: A Comprehensive Review

Fruits and vegetables serve not only as sources of nutrition but also as medicinal agents for the treatment of diverse diseases and maladies. These dietary components are significant resources of phytochemicals that demonstrate therapeutic properties against many illnesses. Fraxin is a naturally occurring coumarin glycoside mainly present in various species of Fraxinus genera, having a multitude of therapeutic uses against various diseases and disorders. This study focuses to investigate the pharmacological activities, botanical sources, and biopharmaceutical profile of the phytochemical fraxin based on different preclinical and non-clinical studies to show the scientific evidence and to evaluate the underlying molecular mechanisms of the therapeutic effects against various ailments. For this, data was searched and collected (as of February 15, 2024) in a variety of credible electronic databases, including PubMed/Medline, Scopus, Springer Link, ScienceDirect, Wiley Online, Web of Science, and Google Scholar. The findings demonstrated favorable outcomes in relation to a range of diseases or medical conditions, including inflammation, neurodegenerative disorders such as cerebral ischemia-reperfusion (I/R) and depression, viral infection, as well as diabetic nephropathy. The phytochemical also showed protective effects such as osteoprotective, renoprotective, pulmoprotective, hepatoprotective, and gastroprotective effects due to its antioxidant capacity. Fraxin has a great capability to diminish oxidative stress-related damage in different organs by stimulating the antioxidant enzymes, downregulating nuclear factor kappa B and NLRP3, and triggering the Nrf2/ARE signaling pathways. Fraxin exhibited poor oral bioavailability because of reduced absorption and a wide distribution into tissues of different organs. However, extensive research is required to decipher the biopharmaceutical profiles, and clinical studies are necessary to establish the efficacy of the natural compound as a reliable therapeutic agent.

Obstructive sleep apnea and bladder pain syndrome/interstitial cystitis in women

PURPOSE

The relationship between obstructive sleep apnea (OSA) and bladder pain syndrome/interstitial cystitis (BPS/IC) remains uncertain. Therefore, this study aimed to compare the frequency of BPS/IC seen in women diagnosed with OSA and in women without OSA.

MATERIAL AND METHODS

The study included a patient group of women with OSA and a control group of women without OSA. All the study participants were administered the Berlin Questionnaire, Epworth Sleepiness Scale, Interstitial Cystitis Symptom Index (ICSI), and the Interstitial Cystitis Problem Index (ICPI). Differences between the women with OSA and the control group were examined.

RESULTS

The study sample consisted of 46 women with OSA and 46 controls. No significant difference was determined between the OSA and control groups concerning age and body mass index (p = 0.810, p = 0.060, respectively). The ESS was greater in the OSA group than in the control group (p = 0.007). The median (IQR) ICSI was 8 (4-11.25) in women with OSA and 5 (1.75-7.15) in controls (p < 0.001). The median (IQR) ICPI was 7 (6.00-10.25) in women with OSA and 6 (1.75-8.00) in controls (p < 0.001).  CONCLUSIONS: The ICSI symptoms and subsequent problems in daily life caused by the symptoms (ICPI) were experienced at a higher rate in patients with OSA than in the control group. There is an association between BPS/IC and OSA.

Nocturnal Pain Crises in an Adult with Sickle Cell Disease

Sickle cell disease is the most common genetic hemoglobinopathy worldwide, characterized by a single-nucleotide mutation that predisposes to hemoglobin polymerization and erythrocyte sickling in hypoxic states. This report describes a 62-year-old male obese patient with a history of sickle cell disease, who presented with worsening nocturnal pain crises without any apparent triggering factor. A thorough evaluation at the outpatient department revealed obstructive sleep apnea. Airway obstruction or decreased respiratory effort during sleep may induce hypoventilation and hypoxia in the context of sleep-disordered breathing, with severe cardiopulmonary complications. Sleep-disordered breathing is considered common in children with sickle cell disease, but the prevalence in adults has not been sufficiently documented. Our patient responded favorably to treatment with continuous positive airway pressure during sleep, showing complete resolution of his symptoms. Timely diagnosis and management are fundamental to improve outcomes and prevent severe complications.

Association of Tumor Necrosis Factor-Alpha, Interleukin-1β, Interleukin-8, and Interferon-γ with Obstructive Sleep Apnea in Both Children and Adults: A Meta-Analysis of 102 Articles

Background: Cytokines may have a significant impact on sleep regulation. In this meta-analysis, we present the serum/plasma levels of tumor necrosis factor-alpha (TNF-α), interleukin (IL)-8, IL-1β, and interferon-gamma (IFN-γ) in both children and adults with obstructive sleep apnea (OSA) in comparison to controls. Methods: Four electronic databases were systematically searched (PubMed, Web of Science, Scopus, and Cochrane Library) through 19 October 2023, without any restrictions on language, date, age, and sex. We used Review Manager version 5.3 to perform meta-analysis and presented the data as standardized mean difference (SMD) and 95% confidence interval (CI) values to evaluate the relationships between the levels of cytokines and OSA. Results: A total of 102 articles (150 independent studies) were included in the meta-analysis. The pooled SMDs in adults were 1.42 (95%CI: 1.11, 1.73; p < 0.00001), 0.85 (95%CI: 0.40, 1.31; p = 0.0002), 0.69 (95%CI: 0.22, 1.16; p = 0.004), and 0.39 (95%CI: -0.37, 1.16; p = 0.31) for TNF-α, IL-8, IL-1β, and IFN-γ, respectively. The pooled SMDs in children were 0.84 (95%CI: 0.35, 1.33; p = 0.0008), 0.60 (95%CI: 0.46, 0.74; p < 0.00001), 0.25 (95%CI: -0.44, 0.93; p = 0.49), and 3.70 (95%CI: 0.75, 6.65; p = 0.01) for TNF-α, IL-8, IL-1β, and IFN-γ, respectively. Conclusions: The levels of proinflammatory cytokines of TNF-α, IL-8, and IL-1β in adults, and TNF-α, IL-8, and IFN-γ in children with OSA, are significantly higher than those in controls.

Continuous Positive Airway Pressure but Not GLP1-mediated Weight Loss Improves Early Cardiovascular Disease in Obstructive Sleep Apnea: A Randomized Proof-of-Concept Study

Rationale: Obstructive sleep apnea (OSA) is an independent risk factor for cardiovascular (CV) morbidity and mortality, but the benefit of continuous positive airway pressure (CPAP) is uncertain. However, most randomized controlled trials have focused on the role of CPAP in secondary prevention, although there is growing evidence of a potential benefit on early CV disease. Weight loss in combination with CPAP may be superior but is difficult to achieve and maintain with conventional measures alone. Objectives: The aim of this study was to gain insights into the effect of CPAP on early atherosclerotic processes and to compare it with a glucagon-like peptide (GLP)-1-mediated weight loss regimen in patients with OSA. Methods: We performed a randomized proof-of-concept study comparing CPAP, a GLP1-mediated weight-loss regimen (liraglutide [Lir]), and both in combination for 24 weeks in 30 consecutive patients with OSA (apnea-hypopnea index >15 events/h; body mass index 30-40 kg/m2; and no history of diabetes, heart failure, or unstable CV disease). In addition to extensive evaluation for CV risk factors and endothelial function at baseline and end of study, subjects underwent 18F-fluoro-2-deoxy-D-glucose positron emission tomography-computed tomography (18F-FDG PET-CT) for the measurement of aortic wall inflammation (target-to-background ratio) and coronary computed tomography angiography for semiautomated coronary plaque analysis. Results: Baseline characteristics were similar between groups. CPAP alone and in combination resulted in greater reduction in apnea-hypopnea index than Lir alone (mean difference, -45 and -43 events/h, respectively, vs. -12 events/h; P < 0.05). Both Lir and combination treatment led to significant weight loss, but only CPAP alone resulted in significant decrease in vascular inflammation (aortic wall target-to-background ratio from 2.03 ± 0.34 to 1.84 ± 0.43; P = 0.010), associated with an improvement in endothelial function and a decrease in C-reactive protein. Low-attenuation coronary artery plaque volume as a marker of unstable plaque also decreased with CPAP (from 571 ± 490 to 334 ± 185 mm3) and with combination therapy (from 401 ± 145 to 278 ± 126 mm3) but not with Lir. Conclusions: These data suggest that CPAP therapy, but not GLP1-mediated weight loss, improves vascular inflammation and reduces unstable plaque volume in patients with OSA. Further large randomized controlled studies are warranted to assess the benefit of CPAP therapy in modifying early CV disease. Clinical trial registered with www.clinicaltrials.gov (NCT04186494).

Cytokines and Obstructive Sleep Apnea in Childhood: Study of a Group of Children

Introduction: Obstructive Sleep Apnea (OSA) in children is characterized by repeated episodes of partial or complete obstruction of the upper airways that impair normal ventilation and cause hypoxia and sleep disruption. These episodes activate innate and adaptive immunity resulting in the production of proinflammatory cytokines: IL-1β, IL-6, TNF-α, and reactive oxygen species. The hypothalamic–pituitary–adrenal (HPT) axis is also activated with alteration of the circadian rhythm of cortisol synthesis. OSA in children, and even more in adults, induces a systemic inflammatory condition that contributes to the genesis of clinical complications: poor growth, learning disabilities, cardiovascular changes, insulin resistance, and metabolic syndrome. Methods: A total of 42 non-obese children (age 1–15 years) were enrolled among those sent to our sleep center to perform full polysomnography (PSG). After PSG, 6 children did not show OSA (controls), 20 had mild OSA (m OSA), and 16 had medium-severe OSA (MS OSA). In vitro IL-1β, TNF-α, and serum cortisol levels were measured at 2 and 8 am in the analyzed groups. Results: Cortisol levels did not differ between controls and OSA children. At 2 am, there were no differences between controls and OSA in TNF-α production, whereas at 8 am, TNF-α was reduced in MS-OSA. IL-1β production showed no differences between OSA and controls. Conclusions: In our population, only TNF-α production is suppressed in MS-OSA: this might indicate a role of OSA severity in inducing inflammation. In adults, the phenomenon is more pronounced due to the habitual greater severity/duration of OSA, presence of comorbidities (cardiovascular and metabolic), and different immune system function.

Murine Pro-Inflammatory Responses to Acute and Sustained Intermittent Hypoxia: Implications for Obstructive Sleep Apnea Research

OBJECTIVES

Obstructive sleep apnea (OSA) is characterized by chronic systemic inflammation; however, the mechanisms underlying these pathologic consequences are incompletely understood. Our objective was to determine the effects of short- versus long-term exposure to intermittent hypoxia (IH) on pro-inflammatory mediators within vulnerable organs impacted by OSA.

STUDY DESIGN

Experimental animal study.

METHODS

A total of 8-10 week old C57BL/6J mice were exposed to normoxic or IH conditions for 7 days (short-term) or 6 weeks (long-term) under 12 h light, 12 h dark cycles. After exposure, multiple tissues were collected over a 24 h period. These tissues were processed and evaluated for gene expression and protein levels of pro-inflammatory mediators from peripheral tissues.

RESULTS

We observed a global decrease in immune response pathways in the heart, lung, and liver compared with other peripheral organs after short-term exposure to IH. Although there were tissue-specific alterations in the gene expression of pro-inflammatory mediators, with down-regulation in the lung and up-regulation in the heart, we also observed reduced protein levels of pro-inflammatory mediators in the serum, lung, and heart following short-term exposure to IH. Long-term exposure to IH resulted in an overall increase in the levels of inflammatory mediators in the serum, lung, and heart.

CONCLUSIONS

We demonstrated novel, longitudinal changes in the inflammatory cascade in a mouse model of OSA. The duration of exposure to IH led to significant variability of inflammatory responses within blood and cardiopulmonary tissues. Our findings further elucidate how inflammatory responses change over the course of the disease in vulnerable organs.

LEVEL OF EVIDENCE

NA Laryngoscope, 134:S1-S11, 2024.

The role of lncRNAs in intermittent hypoxia and sleep Apnea: A review of experimental and clinical evidence

In this narrative review, we present a comprehensive assessment on the putative roles of long non-coding RNAs (lncRNAs) in intermittent hypoxia (IH) and sleep apnea. Collectively, the evidence from cell culture, animal, and clinical research studies points to the functional involvement of lncRNAs in the pathogenesis, diagnosis, and potential treatment strategies for this highly prevalent disorder. Further research is clearly warranted to uncover the mechanistic pathways and to exploit the therapeutic potential of lncRNAs, thereby improving the management and outcomes of patients suffering from sleep apnea.

Exploring the potential relationships among obstructive sleep apnea, erectile dysfunction, and gut microbiota: a narrative review

INTRODUCTION

Poor sleep quality is closely associated with comorbidities affecting a multitude of organ systems. Among the sleep disorders in the population, there has recently been an increase in the prevalence of obstructive sleep apnea (OSA), which has particularly affected men. The intermittent hypoxia and sleep fragmentation associated with OSA can result in the manifestation or aggravation of a number of pathophysiologic conditions, including the impairment of reproductive function in men and women. In this context, erectile dysfunction (ED) is of particular concern. Other consequences of OSA are changes in the gastrointestinal microbiota, with the resultant dysbiosis having potentially harmful consequences that promote downstream exacerbation of various comorbidities.

OBJECTIVES

This narrative review aims to explore the potential relationships among ED, gut microbiota, and OSA.

METHODS

A search of the relevant literature was performed in the PubMed, Embase, Medline, and Web of Science databases.

RESULTS

Sleep is important for regulating the body's functions, and sleep deprivation can negatively affect health. OSA can damage organic functions, including reproductive function, and can lead to ED. Restoring the microbiota and improving sleep can help to improve sexual function or reverse ED and enhance other associated conditions mediated through the gut-brain axis relationship. Probiotics and prebiotics can be used as supportive strategies in the prevention and treatment of OSA, as they help to reduce systemic inflammation and improve intestinal barrier function.

CONCLUSION

A good diet, a healthy lifestyle, and proper bowel function are essential in controlling depression and several other pathologies. Modulating the gut microbiota through probiotics and prebiotics can provide a viable strategy for developing new therapeutic options in treating many conditions. A better understanding of these a priori unrelated phenomena would foster our understanding of the effects of OSA on human fertility and how changes in gut microbiota may play a role.

The immune response to arterial damage in a mouse model of intermittent hypoxia: a transcriptomics analysis

PURPOSE

Mice can develop arterial damage and even atherosclerosis under intermittent hypoxia (IH); however, the specific mechanism of arterial damage induced by IH remains unclear. Hence, this research aimed to illustrate the underlying mechanism linking IH to arterial injury.

MATERIALS AND METHODS

The differential gene expression of the thoracic aorta under normoxia or IH mice was analyzed utilizing RNA sequencing. Furthermore, GO, KEGG pathway, and CIBERSORT analyses were carried out. For verification of the expression of candidate genes affected by IH, quantitative RT-qPCR (qRT-PCR) was conducted. Immunohistochemical (IHC) staining revealed immune cell infiltration in the thoracic aorta.

RESULTS

The thickness of the intima-media of the mouse aorta was increased, and the fiber structure was disordered under IH. Transcriptomics analysis showed that in the aorta, 1137 upregulated genes and 707 downregulated genes were affected by IH, significantly related to the activation of the immune system and cell adhesion. Furthermore, B cell infiltration around the aorta was observed under IH.

CONCLUSIONS

IH might lead to structural changes in the aorta by activating the immune response and enhancing cell adhesion.

Assessment of risk of obstructive sleep apnea with thyroid eye disease and its activity

PURPOSE

To evaluate the association between obstructive sleep apnea (OSA) and thyroid eye disease (TED) and its effect on disease activity.

METHODS

A prospective case-control study was conducted from January 2020 to March 2022. All TED patients (group A) were clinically evaluated. The activity of thyroid eye disease was calculated based on the clinical activity score (CAS), and grading of severity was done according to the EUGOGO classification. All TED patients (group A) were screened for OSA using the Snoring Tired Observed Pressure (STOP)-Bang survey. Age- and gender-matched control group patients (group B) without TED were screened for OSA.

RESULTS

One hundred TED patients and 138 control patients without TED were included in the respective groups. Sixty-two (62%) patients in group A and 48 (34.78%) patients in group B were having high risk of OSA, and this difference was statistically significant (P = 0.001). Further, in group A patients, on univariate analysis, TED activity was significantly associated with a high risk of OSA (P = 0.009). On multivariate logistic regression analysis, OSA also showed significant association with TED activity (odds ratio [OR]: 4.14, 95% confidence interval [CI]: 1.11-18.85 at 10% level; P = 0.05).

CONCLUSION

Our study showed that OSA is significantly associated with TED disease and its activity. However, no significant association was found between OSA and severity of the disease.

Adaptive responses to chronic intermittent hypoxia: contributions from the European Sleep Apnoea Database (ESADA) Cohort

Obstructive sleep apnoea (OSA) is a common disease in the general population, and is associated with increased cardiovascular risk and several comorbidities. Obesity favours upper airway collapsibility, but other pathophysiological traits have been identified, i.e. upper airway muscle activity, modulation of the respiratory drive, and the arousal threshold. OSA causes chronic intermittent hypoxia, inflammatory activation and autonomic imbalance with diurnal and nocturnal sympathetic hyperactivity. Disentangling so many components to investigate the pathogenesis of OSA's consequences is very hard clinically. However, albeit imperfect, clinical medicine constitutes a major source of inspiration for basic research, and a mutual exchange of information is essential between clinicians and physiologists to improve our understanding of disease states. OSA is no exception, and this narrative review will summarize the results of clinical studies performed over the years by the European Sleep Apnoea Database (ESADA) Study Group, to explore the variables linked to markers of intermittent hypoxia as opposed to the traditional assessment of OSA severity based on the frequency of respiratory events during sleep (the Apnoea Hypopnoea Index). The results of the clinical studies indicate that intermittent hypoxia variables are associated with several comorbidities, although evidence of a cause-effect relationship is still missing in many cases. It is also possible that adaptive rather than maladaptive responses could be evoked by intermittent hypoxia. The intensity, duration and frequency of intermittent hypoxia episodes causing adaptive rather than maladaptive responses, and their clinical implications, deserve further investigation.

The ZJU index is associated with the risk of obstructive sleep apnea syndrome in Chinese middle-aged and older people: a cross-sectional study

BACKGROUND

The ZJU index, a novel calculation that combines body mass index, triglycerides, fasting blood glucose and the ratio of alanine aminotransferase to aspartate aminotransferase, is a closely related measure of obesity and insulin resistance. Studies of the ZJU index in relation to obstructive sleep apnea syndrome (OSAS) have not been reported. This study assessed the correlation between the ZJU values and OSAS risk.

METHODS

A total of 2,130 participants who underwent polysomnographic monitoring were included in the study. The participants' basic information and laboratory biochemical indicators were collected, and the ZJU index was computed. The ZJU index was divided into quartiles. The correlation between the different ZJU index levels and OSAS risk was assessed using logistic regression. Drew a receiver operating characteristic (ROC) relationship curve, with prediction efficacy judged by the area under the curve (AUC), and found the optimum cut-off point for ZJU index to predict OSAS. Relative risks were presented as odds ratios (OR). The range of OR values is expressed in the form of 95% confidence intervals (95% CI).

RESULTS

The number of patients diagnosed with OSAS increased progressively with increasing ZJU index (T1: 9.4%; T2: 20.6%; T3: 28.3%; T4: 41.7%; P < 0.001). The additional confounders were adjusted by the logistic regression models, the study revealed an independent correlation between ZJU index and OSAS. (P < 0.001). The OSAS risk was notably higher at the highest ZJU index levels. (OR = 2.046 [95% CI: 1.057 to 3.964]). The ROC curve for the ZJU index showed an AUC of 0.64 (P < 0.001) for males and 0.75 (P < 0.001) for females, with a specificity of 64% and 55% and a sensitivity of 60% and 92% for males and females, respectively, with the optimum cut-off values of 36.568 and 34.722, respectively.

CONCLUSION

A high ZJU index was significantly associated with an increasing risk of OSAS. The ZJU is expected to be a meaningful index for detecting OSAS in the general population.

Blood pressure control in hypertensive sleep apnoea patients of the European Sleep Apnea Database cohort - effects of positive airway pressure and antihypertensive medication

Aims

We analysed longitudinal blood pressure (BP) data from hypertensive obstructive sleep apnoea (OSA) patients in the European Sleep Apnea Database cohort. The study investigated the interaction between positive airway pressure (PAP)-induced BP change and antihypertensive treatment (AHT).

Methods and results

Hypertensive patients with AHT [monotherapy/dual therapy n = 1283/652, mean age 59.6 ± 10.7/60.6 ± 10.3 years, body mass index (BMI) 34.2 ± 6.5/34.8 ± 7.0 kg/m2, apnoea-hypopnoea index 46 ± 25/46 ± 24 n/h, proportion female 29/26%, respectively] started PAP treatment. Office BP at baseline and 2- to 36-month follow-up were assessed. The interaction between AHT drug classes and PAP on BP was quantified and the influences of age, gender, BMI, co-morbidities, BP at baseline, and study site were evaluated. Following PAP treatment (daily usage, 5.6 ± 1.6/5.7 ± 1.9 h/day), systolic BP was reduced by -3.9 ± 15.5/-2.8 ± 17.7 mmHg in mono/dual AHT and diastolic BP by -3.0 ± 9.8/-2.7 ± 10.8 mmHg, respectively, all P < 0.0001. Systolic and diastolic BP control was improved following PAP treatment (38/35% to 54/46% and 67/67% to 79/74%, mono/dual AHT, respectively). PAP treatment duration predicted a larger BP improvement in the monotherapy group. Intake of renin-angiotensin blockers [angiotensin converting enzyme inhibitor (ACEI)/angiotensin receptor blocker (ARB)] alone or in any AHT combination was associated with better BP control. The AHT-dependent BP improvement was independent of confounders.

Conclusion

In this pan-European OSA patient cohort, BP control improved following initiation of PAP. Longer PAP treatment duration, was associated with a favourable effect on BP. Our study suggests that ACEI/ARB, alone or in combination with other drug classes, provides a particularly strong reduction of BP and better BP control when combined with PAP in OSA.

PSGL-1: a novel immune checkpoint driving T-cell dysfunction in obstructive sleep apnea

Introduction

Although higher incidence of cancer represents a major burden for obstructive sleep apnea (OSA) patients, the molecular pathways driving this association are not completely understood. Recently, the adhesion receptor P-selectin glycoprotein-1 (PSGL 1) has been identified as a novel immune checkpoint, which are recognized major hallmarks in several types of cancer and have revolutionized cancer therapy.

Methods

The expression of PSGL-1 and its ligands VISTA and SIGLEC-5 was assessed in the leucocytes of OSA patients and control subjects exploring the role of intermittent hypoxia (IH) using in vitro models. In addition, PSGL-1 impact on T-cells function was evaluated by ex vivo models.

Results

Data showed PSGL-1 expression is upregulated in the T-lymphocytes from patients with severe OSA, indicating a relevant role of hypoxemia mediated by intermittent hypoxia. Besides, results suggest an inhibitory role of PSGL-1 on T-cell proliferation capacity. Finally, the expression of SIGLEC-5 but not VISTA was increased in monocytes from OSA patients, suggesting a regulatory role of intermittent hypoxia.

Discussion

In conclusion, PSGL-1 might constitute an additional immune checkpoint leading to T-cell dysfunction in OSA patients, contributing to the disruption of immune surveillance, which might provide biological plausibility to the higher incidence and aggressiveness of several tumors in these patients.

Obstructive sleep apnea in Parkinson's disease: A prevalent, clinically relevant and treatable feature

Parkinson's disease (PD) is a chronic neurodegenerative disease characterized by motor and non-motor symptoms, including obstructive sleep apnea (OSA), a common comorbid sleep disorder. The prevalence of OSA in PD is high, and its impact on quality of life, accident risk, and limited treatment options underscores the need for vigilant monitoring and effective interventions. OSA is observed in 20-70% of PD patients, whereas the general population exhibits a lower prevalence ranging from 2 to 14%. These discrepancies in prevalence may be attributed to differences in demographic characteristics, sample sizes with selection bias, and variations in scoring systems for apnea and hypopnea events used across different studies. This review highlights the potential pathogenesis of comorbid OSA in PD and provides an overview of ongoing clinical trials investigating interventions for this condition. Several mechanisms have been implicated in the development of OSA in PD, including intermittent hypoxemia, sleep fragmentation, alterations in the glymphatic system homeostasis, upper airway obstruction, and inflammation. Given the adverse effects of PD comorbid OSA, early intervention measures are crucial. It is imperative to conduct longitudinal studies and clinical trials to elucidate the pathogenesis and develop novel and effective interventions for OSA in PD patients. These efforts aim to delay the progression of PD, enhance patients' quality of life, and alleviate the burden on society and families.

Sacubitril/valsartan mitigated intermittent hypoxia related intestinal microbiota alteration and aortic injury

OBJECTIVE

To investigate the influence of sacubitril valsartan sodium (SVS) on chronic intermittent hypoxia (IH) related gut microbiome composition alteration and aortic injury.

METHODS

Experiments were performed using SD rats, which were divided into three groups: control, IH, and SVS group. O2 concentration was decreased to 7-8% at nadir approximately every 3 min in IH group (8 h per day for 6 weeks) or was left unchanged in control group. Rats in SVS group were orally gavaged with SVS at the dosage of 30 mg/kg/day (2 weeks after chronic IH exposure). At week 6, fecal and aortic samples were harvested for 16 s rDNA analysis and histological analysis, respectively.

RESULTS

Principal coordinate analysis and non-metric multidimensional scaling analysis indicated that the bacterial community was altered by chronic IH exposure, while SVS treatment restored the intestinal microbial communities. Further analysis showed that IH decreased the relative abundance of Lactobacillus and Prevotella, while rats treated with SVS was enriched with Firmicutes, Bacilli, Prevotellaceae, and Lactobacillus, which was similar to control rats. Immunohistochemical staining showed that SVS prevented the upregulation of transforming growth factor-β1 and tumor necrosis factor-alpha in the aorta.

CONCLUSION

SVS prevented aortic adverse response to IH, possibly through modulating intestinal microbiota.

Investigating the Role of Serum and Plasma IL-6, IL-8, IL-10, TNF-alpha, CRP, and S100B Concentrations in Obstructive Sleep Apnea Diagnosis

Obstructive sleep apnea (OSA) is a prevalent and underdiagnosed condition associated with cardiovascular diseases, depression, accidents, and stroke. There is an increasing need for alternative diagnostic tools beyond overnight sleep studies that measure the Apnea/Hypopnea Index (AHI). In this single-center, case-control study, we evaluated serum and plasma concentrations of IL-6, IL-8, IL-10, TNF-α, CRP, and S100B in 80 subjects, including 52 OSA patients (27 moderate [15 ≤ AHI ˂ 30], 25 severe [AHI ≥ 30]) and 28 non-OSA controls (AHI 0-5). Participants with OSA showed approximately 2 times higher median concentrations of CRP in plasma, and IL-6 in serum, as well as 1.3 to 1.7 times higher concentrations of TNF-α and IL-8 in plasma compared with the control group. Receiver Operator Characteristic (ROC) curve analysis was performed to evaluate the predictive capabilities of these serum and plasma biomarkers in distinguishing between the OSA and control groups, revealing varying sensitivity and specificity. In summary, in this study, serum and plasma biomarkers CRP, S100B, IL-6, TNF-α, and IL-8 have been shown to be elevated in patients with OSA, correlated positively with disease severity, age, and BMI. These results support the potential role of these biomarkers in diagnosing OSA, supplementing traditional methods such as overnight sleep studies.

Inflammatory biomarkers of neutrophil-to-lymphocyte and platelet-to-lymphocyte ratios in 563 severe OSA patients before and after surgery

BACKGROUND

Evidence has proved that high neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) were risk factors for cardiovascular comorbidities. The alterations of NLR and PLR following obstructive sleep apnea (OSA) treatment were under studied and thus should be investigated. This study aimed to evaluate the changes of inflammatory biomarkers including NLR and PLR in severe OSA patients after surgical interventions of the upper airway, and their relationships with improvements in polysomnographic (PSG) parameters.

METHODS

This retrospective cohort study included 563 consecutive severe OSA patients at a tertiary academic medical center who received OSA surgery, as well as underwent pre- and post-operative polysomnographic (PSG) examinations and blood tests. The changes of major PSG estimates, NLR, and PLR before and at least 3 months after OSA surgery were analyzed using paired t-tests with subgroup analyses. Pearson's correlations were performed to discover which PSG parameter contributed to the improvement of the values.

RESULTS

After OSA surgery, the major PSG estimates, NLR and PLR dropped significantly in the overall population. In those with a higher preoperative NLR (pre-operative NLR≧3) and PLR (pre-operative PLR≧150), the mean (SD) difference of NLR (- 0.8 [1.6], 95% CI - 1.5 to - 0.2) and PLR (- 41.6 [40], 95% CI - 52.8 to - 30.5) were even more substantial. The changes of the "apnea, longest (r = 0.298, P = .037)" and "hypopnea, longest (r = 0.321, P = .026)" were found significantly related to the improvement of PLR.

CONCLUSION

NLR and PLR did significantly drop in severe OSA patients following OSA surgery, and this could be related to the alterations of sleep indices. The findings could possess clinical importance for severe OSA patients after OSA surgeries in reducing possible OSA-associated cardiovascular comorbidities.

Oxidative Stress in Obstructive Sleep Apnea Syndrome: Putative Pathways to Hearing System Impairment

INTRODUCTION

OSAS is a disease that affects 2% of men and 4% of women of middle age. It is a major health public problem because untreated OSAS could lead to cardiovascular, metabolic, and cerebrovascular complications. The more accepted theory relates to oxidative stress due to intermittent hypoxia, which leads, after an intense inflammatory response through multiple pathways, to endothelial damage. The objective of this study is to demonstrate a correlation between OSAS and hearing loss, the effect of the CPAP on hearing function, and if oxidative stress is also involved in the damaging of the hearing system.

METHODS

A review of the literature has been executed. Eight articles have been found, where seven were about the correlation between OSAS and the hearing system, and only one was about the CPAP effects. It is noted that two of the eight articles explored the theory of oxidative stress due to intermittent hypoxia.

RESULTS

All studies showed a significant correlation between OSAS and hearing function (p < 0.05).

CONCLUSIONS

Untreated OSAS affects the hearing system at multiple levels. Oxidative stress due to intermittent hypoxia is the main pathogenetic mechanism of damage. CPAP has no effects (positive or negative) on hearing function. More studies are needed, with the evaluation of extended high frequencies, the execution of vocal audiometry in noisy environments, and the evaluation of potential biomarkers due to oxidative stress.

Alteration of circulating redox balance in coronavirus disease-19-induced acute respiratory distress syndrome

BACKGROUND

Mechanisms underpinning ARDS induced by COVID-19 are mostly immune-mediated, but need to be completely clarified. This study aimed to investigate redox balance in COVID-19 patients with ARDS, trying to recognize possible differences from typical ARDS related to the pathophysiology of severe disease.

METHODS

Patients affected by ARDS and positive for the SARS-CoV-2 virus (N = 40, COVID-19) were compared to ARDS patients negative to the molecular test (N = 42, No COVID-19). Circulating markers of redox balance were measured in serum and erythrocytes, and related to markers of inflammation and coagulability.

RESULTS

No differences in serum markers of oxidative damage were found between both groups, but a reduction in total antioxidant status and serum ceruloplasmin level was observed in COVID-19 rather than No COVID-19 patients. Redox balance alterations were described in erythrocytes from COVID-19 with respect to No COVID-19 group, characterized by increased lipofuscin and malondialdehyde concentration, and reduced glutathione S-transferase and glutathione reductase activity. These markers were associated with circulating indexes of respiratory disease severity (Horowitz index and alveolar-to-arterial oxygen gradient), inflammation (interleukin-6 and interleukin-10), and hypercoagulability (D-dimer) in COVID-19 patients with ARDS.

CONCLUSIONS

ARDS caused by COVID-19 is sustained by impairment of redox balance, particularly in erythrocytes. This alteration is associated with the pro-inflammatory and pro-coagulant status which characterizes severe COVID-19.

Obstructive Sleep Apnea - Influence on the Cardiovascular System and Cognition

Kardiovaskuläre und kognitive Erkrankungen sind ebenso wie die obstruktive Schlafapnoe sehr häufige Krankheiten mit einer erheblichen Beeinträchtigung der Lebensqualität und einer deutlichen sozioökonomischen Bedeutung. Die Auswirkungen einer unbehandelten obstruktiven Schlafapnoe (OSA) auf das kardiovaskuläre und kognitive Erkrankungsrisiko und die Therapieeffekte einer OSA sind für die meisten kardiovaskulären und kognitiven Folgeerkrankungen wissenschaftlich nachgewiesen. Für die klinische Praxis besteht ein deutlicher Bedarf nach mehr Interdisziplinarität. Aus schlafmedizinischer Sicht müssen bei der Therapieindikation das individuelle kardiovaskuläre und kognitive Risiko berücksichtigt und kognitive Erkrankungen bei der Beurteilung der Therapieintoleranz und residuellen Symptomatik beachtet werden. Aus internistischer Sicht sollte bei Patienten mit schlecht einstellbarem Hypertonus, Vorhofflimmern, koronarer Herzkrankheit und Schlaganfall die Abklärung einer OSA in die Diagnostik integriert werden. Bei Patienten mit milder kognitiver Beeinträchtigung, Alzheimer-Krankheit und Depression können sich die typischen Symptome wie Fatigue, Tagesmüdigkeit und Reduktion der kognitiven Leistungen mit OSA-Symptomen überschneiden. Die Diagnostik einer OSA sollte in die Abklärung dieser Krankheitsbilder integriert werden, da eine Therapie der OSA die kognitiven Beeinträchtigungen reduzieren und die Lebensqualität verbessern kann.

Homocysteine Levels in Severe OSA Patients Before and After TORS-OSA Surgery

OBJECTIVE

The increased risk of cardiovascular diseases owing to a high level of serum homocysteine has been widely reported. Literature has demonstrated that patients with obstructive sleep apnea/hypopnea syndrome (OSA) had a higher homocysteine level than control group. This study aimed to investigate the alteration of serum homocysteine levels in severe OSA patients receiving transoral robotic surgery (TORS).

STUDY DESIGN

Retrospective chart review.

SETTING

Tertiary academic medical center.

METHODS

Data of polysomnography (PSG) and serum homocysteine levels before and at least 3 months after the surgery were collected and analyzed via paired t tests. A subgroup analysis based on the preoperative homocysteine level (≥15 mcmol/L, as hyperhomocysteinemia group) was conducted to compare the intergroup differences of homocysteine decrease. Pearson's correlation was used to survey the relationships between the changes of major PSG parameters and the levels of homocysteine decrease at baseline and after TORS-OSA surgery.

RESULTS

Two hundred sixty-one patients with severe OSA were enrolled. There were significant improvements in major PSG parameters after TORS-OSA surgery. Homocysteine levels significantly decreased from 12.1 ± 3.9 to 11.4 ± 3.7 mcmol/L (difference = -0.7 ± 2.8 mcmol/L, p = .001) postoperatively, which was shown in the hyperhomocysteinemia group (difference = -2.9 ± 4.7 mcmol/L, p = .007) to a greater extent. Pearson's correlation revealed that ΔODI (oxygen desaturation index/h) was the predominant estimate with a positive association with Δhomocysteine (r = 0.525, p = .012).

CONCLUSION

TORS-OSA surgery could decrease homocysteine levels in OSA patients. The effects were more relevant in severe OSA patients with abnormal preoperative homocysteine levels.