Obstructive sleep apnoea and cardiovascular consequences: Pathophysiological mechanisms

Diagnostic Role of Circulating Endocan Levels in Obstructive Sleep Apnea: A Systematic Review and Meta-Analysis

Endocan, as an endothelial cell damage marker, plays role in several cardiovascular and non-cardiovascular diseases. This systematic review and meta-analysis evaluates the role of endocan as a potential diagnostic or prognostic biomarker for obstructive sleep apnea (OSA). International databases including PubMed, Embase, Web of Science, and Scopus were searched for relevant studies assessing endocan levels in OSA patients compared with healthy controls or within different severities or comorbidities of OSA. Random-effect meta-analysis was performed in order to calculate the standardized mean difference (SMD) and 95% confidence interval (CI) of serum/plasma endocan in all comparisons. A total of 10 studies were included in our systematic review, among which seven were used in meta-analysis. Meta-analysis showed that endocan levels were significantly higher in patients with OSA compared with healthy controls (SMD 1.29, 95% CI 0.64-1.93, P < .001) and this was not different between serum and plasma subgroups. However, there was no statistical difference between severe and non-severe OSA patients (SMD .64, 95% CI -.22 to 1.50, P = .147). Considerably, higher endocan levels in patients with OSA in comparison with non-OSA individuals might have clinical implications. This association warrants further research due to its potential use as a diagnostic and prognostic biomarker.

Association between the triglyceride glucose index and obstructive sleep apnea and its symptoms: results from the NHANES

BACKGROUND

Certain studies have indicated a link between obstructive sleep apnea and insulin resistance in specific populations. To gain more clarity, extensive research involving a broad sample of the overall population is essential. The primary objective of this study was to investigate this correlation by utilizing data from the National Health and Nutrition Examination Survey database.

METHODS

The analysis incorporated data from the National Health and Nutrition Examination Survey database spanning the time periods from 2005 to 2008 and from 2015 to 2018, with a focus on American adults aged 18 years and older after applying weight adjustments. Key variables such as obstructive sleep apnea, triglyceride glucose index, and various confounding factors were considered. A generalized linear logistic regression model was used to investigate the association between obstructive sleep apnea and the triglyceride glucose index, with additional exploration of the consistency of the results through hierarchical analysis and other techniques.

RESULTS

The study included participants aged between 18 and 90 years, with an average age of 46.75 years. Among the total sample, 50.76% were male. The triglyceride glucose index demonstrated a diagnostic capability for obstructive sleep apnea, with an AUC of 0.701 (95% CI: 0.6619-0.688). According to the fully adjusted model, individuals in the fourth quartile of the triglyceride glucose index showed an increased likelihood of having obstructive sleep apnea compared to those in the first quartile (OR: 1.45; 95% CI: 1.02-2.06; P < 0.05). Subgroup analysis indicated that male sex (OR: 2.09; 95% CI: 1.76-2.45; P < 0.05), younger age (OR: 2.83; 95% CI: 2.02-3.96; P < 0.05), white ethnicity (OR: 2.29; 95% CI: 1.93-2.73; P < 0.05), and obesity (OR: 1.54; 95% CI: 1.28-1.85; P < 0.05) were correlated with an elevated risk of OSA.

CONCLUSIONS

This study demonstrated a strong association between an elevated TG index and OSA. Additionally, the triglyceride glucose index could serve as an independent predictor of obstructive sleep apnea.

TRPC5 channel participates in myocardial injury in chronic intermittent hypoxia

OBJECTIVE

The purpose of this study is to develop an animal model of Chronic Intermittent Hypoxia (CIH) and investigate the role of the TRPC5 channel in cardiac damage in OSAHS rats.

METHODS

Twelve male Sprague Dawley rats were randomly divided into the CIH group and the Normoxic Control (NC) group. Changes in structure, function, and pathology of heart tissue were observed through echocardiography, transmission electron microscopy, HE-staining, and TUNEL staining.

RESULTS

The Interventricular Septum thickness at diastole (IVSd) and End-Diastolic Volume (EDV) of rats in the CIH group significantly increased, whereas the LV ejection fraction and LV fraction shortening significantly decreased. TEM showed that the myofilaments in the CIH group were loosely arranged, the sarcomere length varied, the cell matrix dissolved, the mitochondrial cristae were partly flocculent, the mitochondrial outer membrane dissolved and disappeared, and some mitochondria were swollen and vacuolated. The histopathological examination showed that the cardiomyocytes in the CIH group were swollen with granular degeneration, some of the myocardial fibers were broken and disorganized, and most of the nuclei were vacuolar and hypochromic.

CONCLUSION

CIH promoted oxidative stress, the influx of Ca2+, and the activation of the CaN/NFATc signaling pathway, which led to pathological changes in the morphology and ultrastructure of cardiomyocytes, the increase of myocardial apoptosis, and the decrease of myocardial contractility. These changes may be associated with the upregulation of TRPC5.

Analysis of Macular Vascularization Using Optical Coherence Tomography Angiography in Patients with Obstructive Sleep Apnea Syndrome: A Prospective Clinical Study

Background and Objectives: Given the conflicting data available in the literature, this study aimed to investigate the impact of obstructive sleep apnea syndrome (OSAS) on the macular vascular density (VD) and perfusion density (PD). Materials and Methods: Based on the obstructive apnea-hypopnea index (OAHI), 61 prospectively recruited patients were assigned to either a control group (n = 12; OAHI < 5/h) or an OSAS group (n = 49; OAHI ≥ 5/h). The macular VD and PD of the superficial and deep capillary plexuses (SCP and DCP, respectively) were measured in the parafoveolar and perifoveolar areas using Zeiss PLEX Elite 9000 (6 × 6 mm). The values were compared between the control and OSAS groups. Results: Compared with the control group, the OSAS group demonstrated an increased VD of the DCP in the parafoveolar and perifoveolar areas and PD of the DCP in the perifoveolar area. No significant differences in either the macular VD or PD of the SCP were observed. There was no correlation between the OAHI and macular VD or PD. Conclusions: This study indicates that collateral vessel formation and possible retinal vasodilation occur in the DCP of patients with OSAS.

Chronic intermittent hypoxia-induced hypertension: the impact of sex hormones

Obstructive sleep apnea, a common form of sleep-disordered breathing, is characterized by intermittent cessations of breathing that reduce blood oxygen levels and contribute to the development of hypertension. Hypertension is a major complication of obstructive sleep apnea that elevates the risk of end-organ damage. Premenopausal women have a lower prevalence of obstructive sleep apnea and cardiovascular disease than men and postmenopausal women, suggesting that sex hormones play a role in the pathophysiology of sleep apnea-related hypertension. The lack of protection in men and postmenopausal women implicates estrogen and progesterone as protective agents but testosterone as a permissive agent in sleep apnea-induced hypertension. A better understanding of how sex hormones contribute to the pathophysiology of sleep apnea-induced hypertension is important for future research and possible hormone-based interventions. The effect of sex on the pathophysiology of sleep apnea and associated intermittent hypoxia-induced hypertension is of important consideration in the screening, diagnosis, and treatment of the disease and its cardiovascular complications. This review summarizes our current understanding of the impact of sex hormones on blood pressure regulation in sleep apnea with a focus on sex differences.

Interplay between Hypoxia Inducible Factor-1 and mitochondria in cardiac diseases

Ischemic heart diseases and cardiomyopathies are characterized by hypoxia, energy starvation and mitochondrial dysfunction. HIF-1 acts as a cellular oxygen sensor, tuning the balance of metabolic and oxidative stress pathways to provide ATP and sustain cell survival. Acting on mitochondria, HIF-1 regulates different processes such as energy substrate utilization, oxidative phosphorylation and mitochondrial dynamics. In turn, mitochondrial homeostasis modifications impact HIF-1 activity. This underlies that HIF-1 and mitochondria are tightly interconnected to maintain cell homeostasis. Despite many evidences linking HIF-1 and mitochondria, the mechanistic insights are far from being understood, particularly in the context of cardiac diseases. Here, we explore the current understanding of how HIF-1, reactive oxygen species and cell metabolism are interconnected, with a specific focus on mitochondrial function and dynamics. We also discuss the divergent roles of HIF in acute and chronic cardiac diseases in order to highlight that HIF-1, mitochondria and oxidative stress interaction deserves to be deeply investigated. While the strategies aiming at stabilizing HIF-1 have provided beneficial effects in acute ischemic injury, some deleterious effects were observed during prolonged HIF-1 activation. Thus, deciphering the link between HIF-1 and mitochondria will help to optimize HIF-1 modulation and provide new therapeutic perspectives for the treatment of cardiovascular pathologies.

Nocturnal hypoxaemia is common in adults with sickle cell anaemia

The symptoms and sequelae of sickle cell anaemia (SCA) are caused by the polymerization of deoxygenated sickle haemoglobin, and people with SCA may be uniquely susceptible to adverse outcomes from hypoxia and haemoglobin desaturation. We examined by oximetry adults (aged 18-45 years) with SCA presenting symptoms indicative of polysomnography, at a single institution, irrespective of treatment, for nocturnal hypoxaemia. Clinical labs and blood for in vitro assessments were taken upon enrolment and after 8-12 weeks of oxygen therapy or observation. Of 21 screened participants, nine (43%) had sufficient nocturnal hypoxaemia to warrant oxygen therapy (≥5 min at SpO2 ≤ 88%). Time spent at SpO2 ≤ 88% associated with age (p = 0.0092), annual hospitalizations (p = 0.0018) and anaemia (p = 0.0139), as well as plasma levels of TNFα (p = 0.0019) and IL-4 (p = 0.0147). Longitudinal analysis showed that WBC significantly decreased during the follow-up period in hypoxic individuals but not in non-hypoxic individuals (p = 0.0361 and p = 0.6969 respectively). Plasma levels of CCL2 and IL-1ra tended to increase, while levels of red blood cell reactive oxygen species tended to decrease with oxygen therapy. Overall, nocturnal hypoxaemia was common in this pilot study population and associated with plausible clinical comorbidities; oxygen therapy may decrease inflammation and oxidative damage in hypoxic individuals.

Obstructive sleep apnea syndrome: A frequent and difficult-to-detect complication of radiotherapy for oropharyngeal cancers

This pilot study reveals a higher prevalence of obstructive sleep apnea syndrome (OSAS) in patients treated for oropharyngeal squamous cell carcinoma with radiotherapy compared to the general population. OSAS indicators such as the Epworth Sleepiness Scale seem insufficient in the diagnostic approach to OSAS in this population and systematic screenings should be considered.

Relationship between ODI and sleep structure of obstructive sleep apnea and cardiac remodeling

PURPOSE

The purpose of the study was to evaluate the quantitative relationship between Oxygen Desaturation Index (ODI) and sleep structure of obstructive sleep apnea (OSA) and cardiac remodeling.

METHODS

In this study, patients were enrolled from January 2015 to October 2022, and were divided into 3 groups according to AHI: patients with AHI < 15, patients with 15 ≤ AHI < 30, and 260 patients with AHI ≥ 30. Stratified linear regression was used to analyze independent risk factors for cardiac remodeling in OSA.

RESULTS

A total of 479 patients were enrolled. We found that compared with AHI < 15 group (n = 120), the group with AHI > 30 (n = 260) had increased left atrial anteroposterior diameter, left ventricular end-diastolic internal diameter, left ventricular posterior wall thickness, right ventricular anteroposterior diameter, and interventricular septal thickness (P < 0.05). The group with 15 ≤ AHI ≤ 30 (n = 99) had increased left atrial anteroposterior diameter (P < 0.05). Multivariate linear regression revealed that N2 sleep was an independent risk factor for left ventricular posterior wall thickness, with positive correlation (p < 0.05). N3 sleep was an independent risk factor for transverse right atrial diameter and right ventricular anteroposterior diameter, with negative correlation (P < 0.05). ODI was an independent risk factor for interventricular septal thickness, with positive correlation (P < 0.05). The arousal index was an independent risk factor for increased left atrial anteroposterior diameter, with positive correlation (P < 0.05).

CONCLUSIONS

Increased ODI is an independent risk factor for interventricular septal thickness, while decreased slow wave sleep is an independent risk factor for right heart remodeling in OSA.

Association of the TNF-α-308G>A gene polymorphism with left ventricular geometry and functional abnormalities in obstructive sleep apnea subjects

OBJECTIVE

Tumor necrosis factor-α (TNF-α) can induce left ventricular remodeling. In this study, we investigated whether the TNF-α-308G>A polymorphism is associated with left ventricular geometry (LVG) and left ventricular functional abnormalities in obstructive sleep apnea (OSA) subjects.

METHODS

Two hundred and seventy-eight subjects were enrolled. Echocardiography and genetic data were assessed in all patients. Geometric patterns of the left ventricle were determined from the relative wall thickness and left ventricular mass index (LVMI). Genetic analysis for the TNF-α-308G>A SNP rs1800629 was identified by Sanger sequencing. The correlations of the TNF-α-308G>A polymorphism with LVG and left ventricular function were analyzed by difference analysis and logistic regression.

RESULTS

The chi-square test showed that there were differences in genotype distributions among the four groups (p = 0.033), such that the frequency of GA+AA genotypes was significantly higher in the concentric hypertrophy group than in the normal geometry group (p < 0.05). Independent sample T tests showed that the GA+AA genotypes had higher IVST, LVPWT, LVMI, E/e' values, and lower e' values than those of the GG genotype (p < 0.05). Logistic regression analysis showed that the TNF-α-308G>A polymorphism was independently correlated with eccentric hypertrophy (OR = 2.456, p = 0.047) and concentric hypertrophy (OR = 2.456, p = 0.047).

CONCLUSION

In OSA patients, the TNF-α-308G>A polymorphism was linked to LVG and abnormal left ventricular diastolic function, suggesting that the TNF-α-308G>A polymorphism may have an important influence on LVG alterations.

Obstructive sleep apnea affects cognition: dual effects of intermittent hypoxia on neurons

Obstructive sleep apnea (OSA) is a common respiratory disorder. Multiple organs, especially the central nervous system (CNS), are damaged, and dysfunctional when intermittent hypoxia (IH) occurs during sleep for a long time. The quality of life of individuals with OSA is significantly impacted by cognitive decline, which also escalates the financial strain on their families. Consequently, the development of novel therapies becomes imperative. IH induces oxidative stress, endoplasmic reticulum stress, iron deposition, and neuroinflammation in neurons. Synaptic dysfunction, reactive gliosis, apoptosis, neuroinflammation, and inhibition of neurogenesis can lead to learning and long-term memory impairment. In addition to nerve injury, the role of IH in neuroprotection was also explored. While causing neuron damage, IH activates the neuronal self-repairing mechanism by regulating antioxidant capacity and preventing toxic protein deposition. By stimulating the proliferation and differentiation of neural stem cells (NSCs), IH has the potential to enhance the ratio of neonatal neurons and counteract the decline in neuron numbers. This review emphasizes the perspectives and opportunities for the neuroprotective effects of IH and informs novel insights and therapeutic strategies in OSA.

Influence of Diabetes Mellitus on Glaucoma-Relevant Examination Results in Primary Open-Angle Glaucoma

Primary open-angle glaucoma (POAG) is no longer considered an isolated eye pressure-dependent optic neuropathy, but a neurodegenerative disease in which oxidative stress and neuroinflammation are prominent. These processes may be exacerbated by additional systemic diseases. The most common are arterial hypertension, dyslipidemia, and diabetes mellitus. Using diabetes mellitus as an example, it will be shown how far-reaching the influence of such a systemic disease can be on both the functional and the structural diagnostic methods for POAG. This knowledge is essential, since these interferences can lead to misinterpretations of POAG, which can also affect therapeutic decisions.

The pathogenesis of OSA-related hypertension: what are the determining factors?

Sleep-disordered breathing has a relatively high prevalence, which varies from 3-7% in males and from 2-5% in females in the adult population. Studies published in the literature have shown that sleep apnea is closely related to an increased risk of developing various pathologies, among which arterial hypertension stands out. The prevalence of hypertension in patients suffering from obstructive sleep apnea (OSA) ranges from 35-80% and appears to be related to OSA severity. Approximately 40-50% of patients affected by hypertension are also affected by OSA and this association seems to be stronger in young and middle-aged adults (<50 years of age). The primary objective of this narrative review is to provide an update on what are the main contributing comorbidities to the development of a hypertensive state in patients suffering from OSA, an independent risk factor for diurnal hypertension, implicated as a risk factor for the first stroke, recurrent stroke, and post-stroke mortality. There are a lot of factors that contribute to developing a hypertensive state in OSA patients, some more decisive, others less. More evidence from longitudinal studies is needed on the impact of OSA on cardiovascular risk in females, on the causal link between OSA and arterial hypertension or metabolic diseases, like diabetes and glucose intolerance, and the effect of different kinds of OSA treatment.

Prevalence of headaches and their relationship with obstructive sleep apnea (OSA) - Systematic review and meta-analysis

Obstructive sleep apnea (OSA) is one of the most common sleep disorders; however, there are inconsistent results about the connection and occurrence of primary and secondary headaches in OSA. Therefore, the primary objectives were to estimate the prevalence and potential relationship between all types of headaches and OSA. A systematic review was conducted according to PRISMA 2020 guidelines. Studies were searched in PubMed, Embase, and Web of science up to July 2023. The Joanna Briggs Institute tool assessed the risk of bias. 1845 articles were identified, and 23 studies describing 15,402 patients were included. Pooled prevalence of all headaches in OSA was 33% (95% CI: 0.25-0.41), 33% for morning headaches (95% CI: 0.24-0.45), 25% for sleep apnea headaches (95% CI: 0.18-0.34), 19% for tension-type headache (95% CI: 0.15-0.23), and 16% for migraine (95% CI: 0.09-0.26). Relative risk for the occurrence of headache in OSA patients compared to the non-OSA people was 1.43 (95% CI: 0.92-2.25). OSA females and males had morning headaches with similar frequency. The prevalence of headaches in OSA was moderate. OSA did not increase the risk of headache. There is a need to conduct further studies focused on bidirectional connections between sleep disorders and headaches.

Inflammation and Fibrosis in Sleep-Disordered Breathing after Acute Myocardial Infarction

BACKGROUND

After acute myocardial infarction (AMI), inflammatory processes promote tissue remodeling at the infarct site. Procollagen III amino-terminal propeptide (PIIINP) is a circulating biomarker of type III collagen synthesis that has been shown to be associated with changes in left ventricular ejection fraction (LVEF) and predicts the occurrence of heart failure after AMI. We hypothesize that sleep-disordered breathing (SDB) promotes inflammation and myocardial fibrosis, leading to reduced myocardial salvage. Therefore, in patients with first-time AMI successfully treated with percutaneous coronary intervention (PCI), we aimed to investigate whether circulating levels of high-sensitivity C-reactive protein (hs-CRP) and PIIINP are elevated in patients with SDB compared to patients without SDB.

METHODS AND RESULTS

This cross-sectional analysis included a total of 88 eligible patients with first AMI and PCI pooled from two prospective studies and stratified according to the apnea-hypopnea index (AHI, with SDB: AHI ≥ 15 h-1). We analyzed circulating levels of hs-CRP and PIIINP 3-5 days after PCI. Patients with SDB had significantly higher levels of hs-CRP (18.3 mg/L [95% CI, 8.0-42.6] vs. 5.8 mg/L [95% CI, 4.2-19.8], p = 0.002) and PIIINP (0.49 U/mL [95% CI, 0.40-0.60] vs. 0.33 U/mL [95% CI, 0.28-0.43], p < 0.001). In a multivariable linear regression model accounting for important clinical confounders, SDB significantly predicted circulating levels of hs-CRP (p = 0.028). Similarly, only SDB was independently associated with PIIINP (p < 0.001). Only obstructive but not central AHI correlated with circulating levels of hs-CRP (p = 0.012) and PIIINP (p = 0.006) levels.

CONCLUSIONS

The presence of obstructive SDB after AMI was independently associated with increased circulating levels of hs-CRP and PIIINP. Our results emphasize the important role of SDB as a common comorbidity and indicate increased inflammation and myocardial fibrosis in these patients.

Sleep time on back as a predictor of adherence to positive airway pressure therapy

Upper airway collapse can be effectively dealt with positive airway pressure (PAP), and patient adherence is considered as a major determining factor for success of PAP therapy. This study was performed to determine the potential factors affecting the adherence to PAP in patients with OSA by using polysomnography (PSG) parameters recorded for diagnosis of OSA. The data of 158 patients between December 2018 and July 2021 were collected. They were prescribed with PAP and used the device during the adaptation period for 90 days. They were categorized into adherent and non-adherent group according to the criteria of good adherence as use of PAP ≥ 4 h per night on 70% of nights. Demographic, clinical characteristics, and PSG results were reviewed. Among 158 patients engaged in PAP therapy, 121 patients (76.6%) met the criteria of good adherence. No significant differences were found in good adherence rate regarding demographic and clinical characteristics. None of the polysomnographic factors showed significant differences between adherent and non-adherent groups. However, the percentage of sleep time on back in the adherent group was significantly higher than non-adherent group (p = 0.041). The cut-off value was determined to be 41.45% (95% confidence interval 0.43 to 0.79) by receiver operating characteristic curve analysis and the odds ratio was calculated as 2.97. Only the percentage of sleep time on back appeared to be polysomnographic predictor for identifying good adherence to PAP therapy in OSA patients. However, the conclusions may be limited in generalization due to the small sample size.

Global Prevalence of Obstructive Sleep Apnea in the Elderly and Related Factors: A Systematic Review and Meta-Analysis Study

PURPOSE

The aims of current meta-analysis was to combine data and statistics on the global prevalence of OSA and related factors in older adults.

DESIGN

A systematic review and meta-analysis.

METHODS

To find related studies, various databases were searched including Embase, PubMed, Scopus, Web of Science (WoS), MagIran, and SID (two local databases) using appropriate keywords, MeSH and controlled vocabulary, with no time limitation up to June, 2021. Heterogeneity of studies was evaluated using I2, and Egger's regression intercept was used to detect publication bias.

FINDINGS

39 studies with a total sample size of 33,353 people were included. The pooled prevalence of OSA in older adults was 35.9% (95% confidence interval: 28.7%-43.8%; I2 = 98.81%). Considering the high heterogeneity of included studies, subgroup analysis was conducted and yielded the most prevalent in Asia continent with 37.0% (95% CI: 22.4%-54.5%; I2 = 97.32%). However, heterogeneity was remained at high level. In the majority of studies, OSA was significantly and positively related to obesity, increased BMI, age, cardiovascular diseases, diabetes, and daytime sleepiness.

CONCLUSIONS

Results of this study showed that global prevalence of OSA in older adults is high and is significantly related to obesity, increased BMI, age, cardiovascular diseases, diabetes, and daytime sleepiness. These findings can be used by experts working on the diagnosis and management of OSA in the geriatric population. These findings can be used by experts on the diagnosis and treatment of OSA in the older adults. Due to high heterogeneity, findings should be interpreted with great caution.

Chronic intermittent hypoxia-induced cardiovascular and renal dysfunction: from adaptation to maladaptation

Chronic intermittent hypoxia (CIH) is the dominant pathological feature of human obstructive sleep apnoea (OSA), which is highly prevalent and associated with cardiovascular and renal diseases. CIH causes hypertension, centred on sympathetic nervous overactivity, which persists following removal of the CIH stimulus. Molecular mechanisms contributing to CIH-induced hypertension have been carefully delineated. However, there is a dearth of knowledge on the efficacy of interventions to ameliorate high blood pressure in established disease. CIH causes endothelial dysfunction, aberrant structural remodelling of vessels and accelerates atherosclerotic processes. Pro-inflammatory and pro-oxidant pathways converge on disrupted nitric oxide signalling driving vascular dysfunction. In addition, CIH has adverse effects on the myocardium, manifesting atrial fibrillation, and cardiac remodelling progressing to contractile dysfunction. Sympatho-vagal imbalance, oxidative stress, inflammation, dysregulated HIF-1α transcriptional responses and resultant pro-apoptotic ER stress, calcium dysregulation, and mitochondrial dysfunction conspire to drive myocardial injury and failure. CIH elaborates direct and indirect effects in the kidney that initially contribute to the development of hypertension and later to chronic kidney disease. CIH-induced morphological damage of the kidney is dependent on TLR4/NF-κB/NLRP3/caspase-1 inflammasome activation and associated pyroptosis. Emerging potential therapies related to the gut-kidney axis and blockade of aryl hydrocarbon receptors (AhR) are promising. Cardiorenal outcomes in response to intermittent hypoxia present along a continuum from adaptation to maladaptation and are dependent on the intensity and duration of exposure to intermittent hypoxia. This heterogeneity of OSA is relevant to therapeutic treatment options and we argue the need for better stratification of OSA phenotypes.

Multi-Omics Analysis of Circulating Exosomes in Adherent Long-Term Treated OSA Patients

Obstructive sleep apnea (OSA) is a highly prevalent chronic disease affecting nearly a billion people globally and increasing the risk of multi-organ morbidity and overall mortality. However, the mechanisms underlying such adverse outcomes remain incompletely delineated. Extracellular vesicles (exosomes) are secreted by most cells, are involved in both proximal and long-distance intercellular communication, and contribute toward homeostasis under physiological conditions. A multi-omics integrative assessment of plasma-derived exosomes from adult OSA patients prior to and after 1-year adherent CPAP treatment is lacking. We conducted multi-omic integrative assessments of plasma-derived exosomes from adult OSA patients prior to and following 1-year adherent CPAP treatment to identify potential specific disease candidates. Fasting morning plasma exosomes isolated from 12 adult patients with polysomnographically-diagnosed OSA were analyzed before and after 12 months of adherent CPAP therapy (mean ≥ 6 h/night) (OSAT). Exosomes were characterized by flow cytometry, transmission electron microscopy, and nanoparticle tracking analysis. Endothelial cell barrier integrity, wound healing, and tube formation were also performed. Multi-omics analysis for exosome cargos was integrated. Exosomes derived from OSAT improved endothelial permeability and dysfunction as well as significant improvement in tube formation compared with OSA. Multi-omic approaches for OSA circulating exosomes included lipidomic, proteomic, and small RNA (miRNAs) assessments. We found 30 differentially expressed proteins (DEPs), 72 lipids (DELs), and 13 miRNAs (DEMs). We found that the cholesterol metabolism (has04979) pathway is associated with lipid classes in OSA patients. Among the 12 subjects of OSA and OSAT, seven subjects had complete comprehensive exosome cargo information including lipids, proteins, and miRNAs. Multi-omic approaches identify potential signature biomarkers in plasma exosomes that are responsive to adherent OSA treatment. These differentially expressed molecules may also play a mechanistic role in OSA-induced morbidities and their reversibility. Our data suggest that a multi-omic integrative approach might be useful in understanding how exosomes function, their origin, and their potential clinical relevance, all of which merit future exploration in the context of relevant phenotypic variance. Developing an integrated molecular classification should lead to improved diagnostic classification, risk stratification, and patient management of OSA by assigning molecular disease-specific therapies.

Predictors of Success of Pharyngeal Surgery in the Treatment of Obstructive Sleep Apnea: A Narrative Review

(1) Background: This narrative review aims to explore the predictors of success for pharyngeal surgery in the treatment of obstructive sleep apnea (OSA). An extensive literature search was conducted, identifying relevant studies published up to June 2023, utilizing various databases and key search terms related to OSA, surgical interventions, and predictors of success. The review encompasses both retrospective and prospective studies, case series, and cohort studies to provide a broad understanding of the topic; (2) Methods: Review of English scientific literature on phenotypes of OSA related to predictors of success of pharyngeal surgery; (3) Results: Of 75 articles, 21 were included, in these the following were determined to be factors for surgical success: body mass index (BMI) (8 articles), apnea/hypopnea index (AHI) (8 articles), cephalometry (8 articles), palatine tonsil size (7 articles), Modified Mallampati score (2 articles), genioglossus electromyography (2 articles), Friedman score or upper airway anatomy (3 articles), nasopharyngolaryngoscopy (2 articles), drug-induced sleep endoscopy (DISE) (1 article), oral cavity anatomy (1 article) and oxygen desaturation index (ODI) (1 article); (4) Conclusions: The lack of standardized protocols for the indication of pharyngeal surgery is a reality, however identifying known predictors of surgical success may facilitate homogenizing indications.

The association of nocturnal hypoxemia with dyslipidemia in sleep-disordered breathing population of Chinese community: a cross-sectional study

BACKGROUND

Currently, there is limited and controversial clinical research on the correlation between sleep-disordered breathing (SDB) and dyslipidemia. This discrepancy in findings may be because studies that primarily focused on hospital-based populations may not be applicable to community-based populations. Therefore, the primary objective of this research endeavor is to scrutinize the correlation between nocturnal hypoxemia and blood lipid concentrations among adult individuals residing in the community who exhibit symptoms of SDB. Additionally, this study aimed to identify the nocturnal hypoxia parameters having the strongest correlation with this relationship.

METHODS

This cross-sectional study collected data from The Guangdong Sleep Health Study, which included 3829 participants. Type IV sleep monitoring was employed to measure hypoxemia parameters, and lipoproteins were evaluated using fasting blood samples. To understand the association between dyslipidemia and hypoxemia parameters, a multivariable logistic regression model was used. Subgroup analyses were conducted to stratify data according to age, sex, waist circumference, and chronic diseases.

RESULTS

The age of the individuals involved in the study spanned from 20 to 90 years. The average age of the participants was 56.15 ± 13.11 years. Of the total sample size, 55.7% were male. In the fully adjusted model, the meanSpO2 was negatively associated with hyperlipidemia (0.9303 [95% confidence interval 0.8719, 0.9925]). Upon conducting a nonlinearity test, the relationship between the meanSpO2 and hyperlipidemia was nonlinear. The inflection points were determined to be 95. When meanSpO2 ≥ 95%, a difference of 1 in the meanSpO2 corresponded to a 0.07 difference in the risk of hyperlipidemia.

CONCLUSIONS

This study revealed that higher meanSpO2 is significantly and negatively associated with hyperlipidemia in adult community residents with SDB, particularly when the meanSpO2 exceeds 95. This finding emphasizes the importance of close monitoring for dyslipidemia, which is considered an early indicator of atherosclerosis in patients with SDB who experience nocturnal hypoxia.

Cerebrospinal fluid lipidomic fingerprint of obstructive sleep apnoea in Alzheimer's disease

BACKGROUND

Obstructive sleep apnoea (OSA) has a high prevalence in patients with Alzheimer's disease (AD). Both conditions have been shown to be associated with lipid dysregulation. However, the relationship between OSA severity and alterations in lipid metabolism in the brains of patients with AD has yet to be fully elucidated. In this context, we examined the cerebrospinal fluid (CSF) lipidome of patients with suspected OSA to identify potential diagnostic biomarkers and to provide insights into the pathophysiological mechanisms underlying the effect of OSA on AD.

METHODS

The study included 91 consecutive AD patients who underwent overnight polysomnography (PSG) to diagnose severe OSA (apnoea-hypopnea index ≥ 30/h). The next morning, CSF samples were collected and analysed by liquid chromatography coupled to mass spectrometry in an LC-ESI-QTOF-MS/MS platform.

RESULTS

The CSF levels of 11 lipid species were significantly different between AD patients with (N = 38) and without (N = 58) severe OSA. Five lipids (including oxidized triglyceride OxTG(57:2) and four unknown lipids) were significantly correlated with specific PSG measures of OSA severity related to sleep fragmentation and hypoxemia. Our analyses revealed a 4-lipid signature (including oxidized ceramide OxCer(40:6) and three unknown lipids) that provided an accuracy of 0.80 (95% CI: 0.71-0.89) in the detection of severe OSA. These lipids increased the discriminative power of the STOP-Bang questionnaire in terms of the area under the curve (AUC) from 0.61 (0.50-0.74) to 0.85 (0.71-0.93).

CONCLUSIONS

Our results reveal a CSF lipidomic fingerprint that allows the identification of AD patients with severe OSA. Our findings suggest that an increase in central nervous system lipoxidation may be the principal mechanism underlying the association between OSA and AD.

Obstructive Sleep Apnea

OBJECTIVE

Obstructive sleep apnea (OSA) is the most common type of sleep-disordered breathing. This article describes advances in the diagnosis, testing, treatment, and monitoring of OSA.

LATEST DEVELOPMENTS

Home sleep apnea testing and in-laboratory polysomnography are the most commonly used diagnostic tools in the identification and monitoring of OSA, but new methods for diagnosis and at-home monitoring of treatment response are being developed and validated. While the apnea-hypopnea index is regularly used to define OSA severity, recognition is increasing of its inability to risk-stratify patients. Other sleep study data including arousal threshold, hypoxic burden, and pulse rate variability as well as clinical characteristics can help with risk stratification. The most effective treatment is continuous positive airway pressure (CPAP), which can be limited by adherence and tolerance in some patients. Newer masks and comfort features including heated tubing and expiratory pressure relief may improve tolerance to positive airway pressure (PAP) therapy. Additional treatment options include other PAP modalities, mandibular advancement devices, tongue stimulation therapy, negative inspiratory pressure, nasal expiratory pressure valves, nasal congestion treatments, upper airway surgeries including hypoglossal nerve stimulation, and medications.

ESSENTIAL POINTS

OSA is a common disorder that causes sleep and daytime symptoms and increases the risk of neurologic and medical complications. Neurologists should be aware of atypical presentations and understand the diagnostic and treatment options.

Oral appliance therapy for the management of obstructive sleep apnea in adults: an umbrella review protocol

OBJECTIVE

The objective of this review is to summarize the evidence on the effectiveness of oral appliance therapy compared with other therapeutic approaches (continuous positive airway pressure, maxillomandibular and upper airway surgeries, behavioral techniques) for the management of obstructive sleep apnea in adults.

INTRODUCTION

For primary snoring, mild to moderate obstructive sleep apnea, and patients with a severe condition who are intolerant of continuous positive airway pressure therapy, an oral appliance is the treatment of choice among conservative procedures. The effectiveness of these appliances is largely determined by a variety of parameters, including the severity of sleep apnea (mild, moderate, severe), materials and methods used to fabricate the appliance, and the degree of mandibular protrusion. Thus, it is important to evaluate the effectiveness of oral appliances in the reduction of sleep apnea.

INCLUSION CRITERIA

This review will include systematic reviews of quantitative studies reporting on the effectiveness of oral appliances for the treatment of obstructive sleep apnea of any severity, confirmed using polysomnography. The primary outcome will be measured by reduction in the apnea-hypopnea index.

METHODS

A search will be conducted of MEDLINE, Cochrane Database of Systematic Reviews, Scopus, Web of Science, CINAHL, Epistemonikos, Embase, ProQuest Dissertations and Theses, and Shodhganga Dissertations and Theses from database inception until the present, with no language restrictions. Google Scholar will be searched manually. Two independent reviewers will screen titles, abstracts, and full-text articles and perform data extraction. Quality assessment will be conducted using the standard JBI critical appraisal tool. Data will be extracted from systematic reviews and a synthesis of the findings will be presented. The certainty will be assessed using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE).

REVIEW REGISTRATION

PROSPERO CRD42021258515.

Hypoxia Affects Autophagy in Human Umbilical Vein Endothelial Cells via the IRE1 Unfolded Protein Response

OBJECTIVE

The purpose of this study was to investigate the role of the unfolded protein response, specifically the inositol-requiring enzyme 1 (IRE1) signaling pathway, in hypoxia-induced autophagy in human umbilical venous endothelial cells (HUVECs).

METHODS

The expression of IRE1 and autophagy relative protein in HUVECs with hypoxia was explored by Western blotting, qRT-PCR and confocal microscopy. Further, we evaluated the biological effects of HUVECs by tube formation assay and wound healing assay in vitro. Finally, we examined the function of IRE1 in local blood vessels through animal models.

RESULTS

Hypoxia activated the IRE1 signaling pathway and induced autophagy in a time-dependent manner in HUVECs and further influenced the biological effects of HUVECs. Intraperitoneal injection of IRE1 inhibitors inhibited local vascular autophagy levels and lipid accumulation in model animals.

CONCLUSION

Hypoxia can induce autophagy and activate the IRE1 signaling pathway in HUVECs and the IRE1 signaling pathway is involved in autophagy in hypoxic conditions.

Is Continuous Positive Airway Pressure a Valid Alternative to Sildenafil in Treating Sexual Dysfunction among OSA Patients? A Systematic Review and Meta-Analysis

Background and Objectives: This study aimed to assess the comparative effectiveness of continuous positive airway pressure (CPAP) therapy and sildenafil pharmacological therapy in improving sexual function among patients with obstructive sleep apnea (OSA) and erectile dysfunction (ED). Materials and methods: Population: Patients affected by OSA and ED; Intervention: CPAP therapy vs. Comparison: Sildenafil pharmacological therapy; Outcomes: Improvement in erectile function, as measured by the International Index of Erectile Function 5 (IIEF-5) scoring system; Time: A systematic review of the literature from the past 20 years; Study Design: Observational studies comparing erectile function improvements after OSA treatment. Results: A total of eight papers were included in the qualitative summary, involving four hundred fifty-seven patients with ED and OSA. Erectile function improvements were observed in both treatment groups. After sildenafil and CPAP treatment, the mean IIEF-5 domain scores were 37.7 and 27.3, respectively (p < 0.001). Sildenafil 100 mg demonstrated a higher therapeutic impact compared to CPAP treatment. Conclusions: CPAP therapy significantly improved sexual parameters in most studies for OSA patients with ED. The findings suggest that CPAP therapy effectively alleviates erectile dysfunction symptoms, resulting in improved sexual performance in OSA patients. The comparison of the two treatments indicates that sildenafil has a more substantial therapeutic impact on erectile function than CPAP therapy; however, a combined treatment will provide a cumulative effect.

Evaluation of Inflammation and Oxidative Stress Markers in Patients with Obstructive Sleep Apnea (OSA)

Background: The identification of circulating markers of oxidative stress and systemic inflammation might enhance risk stratification in obstructive sleep apnea (OSA). We investigated the association between specific haematological parameters, as easily measurable markers of oxidative stress and inflammation, and the degree of hypoxia during polysomnography using the apnea hypopnea index (AHI), oxygen desaturation index (ODI), and oxygen saturation (SpO₂), in OSA patients. Methods: Associations between polysomnographic parameters and demographic, clinical, and laboratory characteristics were assessed in a consecutive series of patients with OSA attending the Respiratory Disease Unit of the University Hospital of Sassari, north Sardinia (Italy), between 2015 and 2019. Results: In 259 OSA patients (195 males and 64 females), the body mass index (BMI) was significantly and positively associated with the AHI and ODI, and negatively associated with the mean SpO₂. No haematological parameter was independently associated with the AHI or ODI. By contrast, albumin, neutrophil, and monocyte counts, and the systemic inflammatory response index (SIRI) were independently associated with a lower SpO₂. Conclusions: Our results suggest that albumin and specific haematological parameters are promising markers of reduced oxygen saturation in OSA.

Molecular mechanisms of postoperative atrial fibrillation in patients with obstructive sleep apnea

Obstructive sleep apnea (OSA) promotes atrial remodeling and fibrosis, providing a substrate for atrial fibrillation (AF). Herein, we investigate the pathophysiological mechanisms of AF in association with OSA in a cohort of cardiac surgery patients. A prospective study including patients undergoing cardiac surgery. Biomarkers reflective of AF pathophysiology (interleukin [IL-6], C-reactive protein [CRP], von Willebrand factor [vWF], N-terminal pro-brain natriuretic peptide [NT-proBNP], high-sensitivity Troponin T [hs-TnT], and Galectin-3 [Gal-3]) was assessed by functional or immunological assays. miRNAs involved in AF were analyzed by reverse transcription-polymerase chain reaction (RT-PCR). Using atrial tissue samples, fibrosis was assessed by Masson's trichrome. Connexin 40 and 43 (Cx40; Cx43) were evaluated by immunolabeling. Fifty-six patients (15 with OSA and 41 non-OSA) were included in this hypothesis-generating pilot study. OSA group had a higher incidence of postoperative AF (POAF) (46.7% vs. 19.5%; p = .042), presented an increased risk of POAF (OR 3.61, 95% CI 1.01-12.92), and had significantly higher baseline levels of NT-proBNP (p = .044), vWF (p = .049), Gal-3 (p = .009), IL-6 (p = .002), and CRP (p = .003). This group presented lower levels of miR-21 and miR-208 (both p < .05). Also, lower Cx40 levels in POAF and/or OSA patients (50.0% vs. 81.8%, p = .033) were found. The presence of interstitial fibrosis (according to myocardial collagen by Masson's trichrome) was raised in OSA patients (86.7% vs. 53.7%, p = .024). Several biomarkers and miRNAs involved in inflammation and fibrosis were dysregulated in OSA patients, which together with a higher degree of interstitial fibrosis, altered miRNA, and Cxs expression predisposes to the development of a substrate that increases the AF risk.

Sleep Quality, Metabolic Function, Physical Activity, and Neurocognition Among Individuals with Resistant Hypertension

BACKGROUND

Resistant hypertension (RH) is a major risk factor for stroke, cognitive decline, and dementia. Sleep quality is increasingly suggested to play an important role linking RH to cognitive outcomes, although the mechanisms linking sleep quality to poor cognitive function have yet to be fully delineated.

OBJECTIVE

To delineate biobehavioral mechanisms linking sleep quality, metabolic function, and cognitive function among 140 overweight/obese adults with RH in the TRIUMPH clinical trial.

METHODS

Sleep quality was indexed using actigraphy measures of sleep quality and sleep fragmentation, as well as self-reported sleep quality from the Pittsburgh Sleep Quality Index (PSQI). Cognitive function was assessed using a 45-minute battery assessing executive function, processing speed, and memory. Participants were randomized to a cardiac rehabilitation-based lifestyle program (C-LIFE) or a standardized education and physician advice condition (SEPA) for 4 months.

RESULTS

Better sleep quality at baseline was associated with better executive function (B = 0.18 p = 0.027), as well as greater fitness (B = 0.27, p = 0.007) and lower HBA1c (B = -0.25, p = 0.010). Cross-sectional analyses revealed that the sleep quality executive function association was mediated by HBA1c (B = 0.71 [0.05, 2.05]). C-LIFE improved sleep quality (-1.1 [-1.5, -0.6] versus+-0.1 [-0.8, 0.7]) and actigraphy steps (+922 [529, 1316] versus+56 [-548, 661]), with actigraphy mediating improvements in executive function (B = 0.40 [0.02, 1.07]).

CONCLUSION

Better metabolic function and improved physical activity patterns levels play important roles linking sleep quality and executive function in RH.

Retrospective Analysis of Real-World Data for the Treatment of Obstructive Sleep Apnea with Slow Maxillary Expansion Using a Unique Expansion Dental Appliance (DNA)

In addition to mandibular advancement devices, dental expansion appliances are an important clinical approach for achieving an increased intra-oral space that promotes airflow and lessens the frequency or severity of apneic events in patients diagnosed with obstructive sleep apnea (OSA). It has been thought that dental expansion in adults must be preceded by oral surgery; however, in this paper, we examine the results of a new technique for slow maxillary expansion without any surgical procedures. The palatal expansion device, DNA (Daytime-Nighttime Appliance), was reviewed in this retrospective study, particularly regarding its effects on measurements of transpalatal width, airway volume, and apnea-hypopnea indices (AHI) as well as its common modalities and complications. The DNA effectively reduced AHI by 46% (p = 0.00001) and significantly increased both airway volume and transpalatal width (p < 0.00001). After DNA treatment, 80% of patients showed some improvement in AHI scores with 28% of patients having their OSA symptoms completely resolved. Compared to the use of mandibular appliances, this approach is intended to create a sustained improvement in airway management that can reduce or eliminate dependence on continuous positive airway pressure (CPAP) or other OSA treatment devices.

Dyslipidemia prevalence in nonobese, nondiabetic patients with obstructive sleep apnea: does sex matter?

STUDY OBJECTIVES

Dyslipidemia in obstructive sleep apnea (OSA) has been attributed to confounding obesity and/or diabetes. This study aimed to examine lipid profiles in nondiabetic, nonobese patients with OSA and identify the possible effects of age and sex.

METHODS

We retrospectively evaluated the lipid parameters of 3,050 adults who underwent polysomnography. A total of 2,168 patients were excluded due to obesity (body mass index ≥ 30 kg/m2), diabetes, alcoholism, untreated hypothyroidism, lipid-lowering drug use, missing sleep data, or treatment for suspected OSA.

RESULTS

Of 882 patients (75% males, aged 46.8 ± 12.2 years) included in the study, 88.4% had OSA. Levels of total cholesterol (P = .003), low-density-lipoprotein (LDL) cholesterol (P = .005), non-high-density-lipoprotein (non-HDL) cholesterol (P = .001), and triglycerides (P = .007) were significantly higher in patients with OSA than in those without, whereas HDL-cholesterol levels did not differ. The proportion of patients with hypercholesterolemia and/or elevated non-HDL cholesterol (>  160 mg/dL) was significantly higher in OSA than in non-OSA. Correlation analyses by sex revealed stronger and more significant relationships between lipid parameters and apnea-hypopnea index in women than in men (r = .135, P < .001, vs r = .080, P = .043 for total cholesterol; r = .111, P < .001, vs r = .080, P = .046 for non-HDL cholesterol; r = .122, P < .001, vs r = .061, P = .107 for LDL cholesterol, respectively). In regression analysis, the rate of hypercholesterolemia increased with age (P < .001 for women and P = .031 for men); non-HDL- and LDL-cholesterol levels significantly increased with OSA severity (P = .035 and P = .023, respectively) and age (P = .004 and P = .001, respectively) in women.

CONCLUSIONS

After excluding confounding obesity and diabetes, patients with OSA have an impaired lipid profile including total cholesterol, LDL cholesterol, non-HDL cholesterol, and triglycerides. A significant association between dyslipidemia and OSA severity was observed in women but not in men.

CITATION

Basoglu OK, Tasbakan MS, Kayikcioglu M. Dyslipidemia prevalence in nonobese, nondiabetic patients with obstructive sleep apnea: does sex matter? J Clin Sleep Med. 2023;19(5):889-898.

Obstructive Sleep Apnea, Metabolic Dysfunction, and Periodontitis-Machine Learning and Statistical Analyses of the Dental, Oral, Medical Epidemiological (DOME) Big Data Study

This study aimed to analyze the associations of obstructive sleep apnea (OSA) with dental parameters while controlling for socio-demographics, health-related habits, and each of the diseases comprising metabolic syndrome (MetS), its consequences, and related conditions. We analyzed data from the dental, oral, and medical epidemiological (DOME) cross-sectional records-based study that combines comprehensive socio-demographic, medical, and dental databases of a nationally representative sample of military personnel for one year. Analysis included statistical and machine learning models. The study included 132,529 subjects; of these, 318 (0.2%) were diagnosed with OSA. The following parameters maintained a statistically significant positive association with OSA in the multivariate binary logistic regression analysis (descending order from highest to lowest OR): obesity (OR = 3.104 (2.178-4.422)), male sex (OR = 2.41 (1.25-4.63)), periodontal disease (OR = 2.01 (1.38-2.91)), smoking (OR = 1.45 (1.05-1.99)), and age (OR = 1.143 (1.119-1.168)). Features importance generated by the XGBoost machine learning algorithm were age, obesity, and male sex (located on places 1-3), which are well-known risk factors of OSA, as well as periodontal disease (fourth place) and delivered dental fillings (fifth place). The Area Under Curve (AUC) of the model was 0.868 and the accuracy was 0.92. Altogether, the findings supported the main hypothesis of the study, which was that OSA is linked to dental morbidity, in particular to periodontitis. The findings highlight the need for dental evaluation as part of the workup of OSA patients and emphasizes the need for dental and general medical authorities to collaborate by exchanging knowledge about dental and systemic morbidities and their associations. The study also highlights the necessity for a comprehensive holistic risk management strategy that takes systemic and dental diseases into account.

Association between sleep-disordered breathing and self-reported sinusitis in adults in the United States: NHANES 2005-2006

OBJECTIVES

The association between sleep-disordered breathing (SDB) and sinusitis has been widely studied; however, research on SDB-related sleep problems and sinusitis are limited. This study aims to determine the relationship between SDB-related sleep problems, SDB symptom score, and sinusitis.

METHODS

After the screening, data were analyzed from 3414 individuals (≥20 years) from the 2005-2006 National Health and Nutrition Examination Survey questionnaire. Data on snoring, daytime sleepiness, obstructive sleep apnea (snorting, gasping, or cessation of breathing while sleeping), and sleep duration were analyzed. The SDB symptom score was determined based on a summary of the scores of the above four parameters. Pearson chi-square test and logistic regression analysis were used in statistical analyses.

RESULTS

After adjusting for confounders, self-reported sinusitis was strongly correlated with frequent apneas (OR: 1.950; 95% CI: 1.349-2.219), excessive daytime sleepiness (OR: 1.880; 95% CI: 1.504-2.349), and frequent snoring (OR: 1.481; 95% CI: 1.097-2.000). Compared to an SDB symptom score of 0, the higher the SDB symptom score, the higher the risk of self-reported sinusitis. For the subgroup analyses, this association was significant in females and across ethnic groups.

CONCLUSION

In the United States, SDB is significantly associated with self-reported sinusitis in adults. In addition, our study suggests that patients with SDB should be aware of the risk of developing sinusitis.

Continuous positive airway pressure treatment reduces renal tubular damage in patients with obstructive sleep apnea: A retrospective single-center cohort study

BACKGROUND

Chronic intermittent hypoxia (IH) plays a significant role in the pathogenesis of obstructive sleep apnea (OSA) comorbidities. The prevalence of chronic kidney disease is higher in patients with OSA than the general population, and renal function decline is well correlated with renal tubular injury. However, little is known about the impact of OSA-induced chronic IH on the renal tubules.

METHODS

We conducted a retrospective survey of clinical records performing multiple regression analysis and cluster analysis with particular attention to the 3% oxygen desaturation index (ODI) and urinary N-acetyl-β-d-glucosaminidase (NAG).

RESULTS

In patients with suspicion of OSA, urinary NAG creatinine ratio (UNCR) was elevated as their 3% ODI increased (n = 197, p < 0.001), and the elevated UNCR decreased following CPAP treatment in patients with OSA (n = 46, p = 0.014). Multiple regression analysis showed that 3% ODI was associated with UNCR. Cluster analysis identified three clusters of patients with OSA, including two younger age clusters, one of which was characterized by high BMI, high 3% ODI, and high prevalence of major comorbidities. In a comparative analysis of younger age cases (age ≤ 55, n = 82), the UNCR level was higher in patients with severe 3% ODI (3% ODI > 40 events/h, n = 24) (p = 0.014).

CONCLUSIONS

Our results indicate that even at younger ages, OSA patients with severe chronic IH and major comorbidities are susceptible to renal tubular damage. Early treatment with CPAP may attenuate renal tubular injury and progression toward end-stage renal disease.

Association between glycolipids and risk of obstructive sleep apnea: A population-based study

Background

This study aimed to investigate the associations between multiple glycolipid biomarkers and the risk of obstructive sleep apnea (OSA).

Methods

Participants (10,286) aged from 35 to 74 years old were included in this cross-sectional study from the baseline survey of the Guangzhou Heart Study. OSA was ascertained using both Berlin Questionnaire and STOP-BANG Questionnaire. Fasting blood samples were collected from each participant; fasting blood glucose (FBG) and serum concentrations of high-density lipoprotein cholesterol (HDL-CH), low-density lipoprotein cholesterol (LDL-CH), total cholesterol (TC), and triglyceride (TG) were determined. Odds ratio (OR) with 95% confidence interval (CI) was calculated using the multivariate logistic regression model after adjustment for covariates.

Results

Of the participants included, 15.56% were categorized into the pre-OSA group, and 8.22% into the OSA group. When comparing the highest with the lowest quartiles, HDL-HC was associated with a 22% (OR: 0.78, 95% CI: 0.65–0.94) and 41% (OR: 0.59, 95% CI: 0.45–0.78) reduced risk of pre-OSA and OSA, triglyceride was associated with a 32% (OR 1.32, 95% CI 1.08–1.60) and a 56% (OR 1.56, 95% CI 1.18–2.07) increased risk of pre-OSA and OSA, and FBG was associated with a 1.37-fold (95% CI 1.13–1.67) risk of pre-OSA and 1.38-fold (95% CI 1.03–1.85) risk of OSA. A significant exposure-response trend was observed for HDL-HC, TG, and FBG with both OSA and Pre-OSA (all p &lt; 0.05). No significant association of LDL-CH and TC with the risk of both pre-OSA and OSA was observed.

Conclusion

The findings suggest that serum HDL-CH was inversely associated with OSA risk, while elevated serum TG and FBG could increase the risk of OSA. Healthy glycolipid metabolism warrants more attention in the field of OSA prevention.

Obstructive Sleep Apnea as a Predictor of a Higher Risk of Significant Coronary Artery Disease Assessed Non-Invasively Using the Calcium Score

The aim of this study was to assess the coronary artery calcium score in patients with obstructive sleep apnea (OSA). The study group (group A) consisted of 62 patients with diagnosed obstructive sleep apnea (mean age: 59.12 ± 9.09 years, mean AHI index in polysomnography: 20.44 ± 13.22/h), and 62 people without diagnosed obstructive sleep apnea (mean age 59.50 ± 10.74 years) constituted the control group (group B). The risk of significant coronary artery disease was assessed in all patients, based on the measurement of the coronary artery calcium score (CACS) using computed tomography. The following cut-off points were used to assess the risk of significant coronary artery disease: CACS = 0—no risk, CACS 1–10—minimal risk, CACS 11–100—low risk, CACS 101–400—moderate risk, and CACS > 400—high risk. Group A was characterized by statistically significantly higher CACS than group B (550.25 ± 817.76 vs. 92.59 ± 164.56, p < 0.05). No risk of significant coronary artery disease was statistically significantly less frequent in group A than in group B (0.0% vs. 51.6%, p < 0.05). A high risk of significant coronary artery disease was statistically significantly more frequent in group A than in group B (40.3% vs. 4.8%, p < 0.05). In group A, patients with severe OSA and patients with moderate OSA had statistically significantly higher CACS than patients with mild OSA (910.04 ± 746.31, 833.35 ± 1129.87, 201.66 ± 192.04, p < 0.05). A statistically significant positive correlation was found between the AHI and CACS (r = 0.34, p < 0.05). The regression analysis showed that OSA, male gender, older age, type 2 diabetes, peripheral arterial disease, and smoking were independent risk factors for higher CACS values. AHI ≥ 14.9 was shown to be a predictor of a high risk of significant coronary artery disease with a sensitivity and specificity of 62.2% and 80.0%, respectively. In summary, obstructive sleep apnea should be considered an independent predictive factor of a high risk of significant coronary artery disease (based on the coronary artery calcium score).

The prognostic role of ultrasound and magnetic resonance imaging in obstructive sleep apnoea based on lateral oropharyngeal wall obstruction

PURPOSE

This study examined the prognostic value of the lateral pharyngeal wall (LPW)-based obstruction and obstructive sleep apnoea (OSA) prediction using ultrasound (US) and MRI (magnetic resonance imaging).

METHODS

One hundred patients with and without OSA were enrolled, according to overnight polysomnography. The LPW thickness (LPWT) was measured using a Philips Ingenia 1.5 T MRI device, and US measurements were carried out at rest and during Müller's manoeuvre (MM) with a Samsung RS85 device. The obstruction was localised under drug-induced sleep endoscopy.

RESULTS

Significantly greater LPWT using MRI was observed in the OSA group compared to the control group, while US results showed a significant difference only in the case of LPWT during MM on the left side. Obese patients presented significantly higher LPWT values. A significant correlation between BMI and LPWT was observed. Men presented significantly higher LPWT MRI values and left-sided LPWT using US compared to women. LPWT and AHI parameters were significantly correlated. The severity of LPW obstruction correlated with LPWT, while the LPW collapse significantly correlated with AHI. The severity of LPW collapse differed depending on the AHI values. Using US LPWT values and anthropometric parameters, a 93% effectiveness in OSA prognostication and 89% in LPWT-based obstruction were detected. MRI detected OSA in 90% and LPW-based obstruction in 84%. US successfully detected LPW-based collapse severity in 67%.

CONCLUSION

US LPWT measurements were helpful in detecting OSA and LPWT-based obstruction. These examinations may be useful for surgical planning.

Association between preserved ratio impaired spirometry and sleep apnea in a Chinese community

OBJECTIVE

This study investigated the association between obstructive sleep apnea (OSA) and preserved ratio impaired spirometry (PRISm) in a community population.

METHODS

Baseline data from a prospective cohort study, the Predictive Value of Combining Inflammatory Biomarkers and Rapid Decline of FEV1 for COPD (PIFCOPD), were used for cross-sectional analysis. Participants aged 40-75 years were recruited from the community and their demographic information and medical history were collected. The STOP-Bang questionnaire (SBQ) was used to assess the risk of OSA. Pulmonary function tests were performed using a portable spirometer (COPD-6) and forced expiratory volume in 1 s (FEV1) and 6 s (FEV6) were measured. Routine blood, biochemical, high-sensitivity C-reactive protein (hs-CRP), and interleukin-6 tests were also performed. The pH of the exhaled breath condensate was determined.

RESULTS

A total of 1183 participants were enrolled, of which 221 with PRISm and 962 with normal lung function. The neck circumference, waist-to-hip ratio, hs-CRP concentration, proportion of males, cigarette exposure, number of current smoker, high risk of OSA, and prevalence of nasal and ocular allergy symptoms were significantly higher in the PRISm group than in the non-PRISm group (p < .05). Logistic regression showed that the risk of OSA (odds ratio, 1.883; 95% confidence interval, 1.245-2.848), waist-to-hip ratio, current smoking, and prevalence of nasal allergy symptoms were independently associated with PRISm after correcting for age and sex.

CONCLUSION

These findings showed that OSA prevalence is independently associated with PRISm prevalence. Further studies should confirm the relationship between systemic inflammation in OSA, localized inflammation of the airways, and impaired lung function.

MoCA-T como herramienta de evaluación remota para precisar deterioro cognitivo en pacientes con SAHOS moderado a severo

La pandemia de COVID-19 ha dado lugar al surgimiento de herramientas tecnológicas que permiten la valoración de pacientes de forma remota. La prueba de evaluación cognitiva de Montreal, versión telefónica (MoCA-T), es una de ellas. Se considera como un recurso de la telemedicina que permite la tamización cognitiva a distancia en épocas de pandemia y en la población con dificultades en el acceso a los centros de salud. El deterioro cognitivo leve (DCL) es un hallazgo usual en pacientes con síndrome de apnea-hipopnea obstructiva del sueño (SAHOS); sin embargo, no se ha estudiado la aplicación de pruebas telefónicas para su tamización cognitiva. El objetivo principal de este trabajo es determinar la frecuencia de deterioro cognoscitivo mediante la aplicación de MoCA-T como prueba de tamización remota en pacientes con SAHOS moderado y severo. Para ello, se aplicó la prueba de MoCA-T en 104 pacientes entre 18 y 65 años con diagnóstico polisomnográfico de SAHOS moderado y severo, excluyéndose a pacientes con comorbilidades que afectasen las capacidades cognoscitivas. Se obtuvieron resultados anormales de MoCA-T en el 43% de los pacientes, siendo los dominios cognitivos de la memoria y la atención los más comúnmente afectados. Finalmente, los resultados anormales de MoCA-T se correlacionaron con la autopercepción de las dificultades en la memoria, estando más frecuentemente alterada en quienes manifestaron quejas cognitivas. La prueba MoCA-T podría ser una herramienta tecnológica breve, validada y factible para realizar el tamizaje cognitivo de pacientes con SAHOS en épocas de pandemia y en pacientes con barreras asistenciales.

Altered cerebral blood flow and white matter during wakeful rest in patients with obstructive sleep apnea: a population-based retrospective study

OBJECTIVES

To explore changes in cerebral blood flow (CBF) and white matter during wakeful rest in patients with obstructive sleep apnea (OSA).

METHODS

The subjects comprised OSA patients and age- and sex-matched non-sleep apnea (NSA) subjects from December 2020 to December 2021. All subjects underwent structural and arterial spin labeling MRI examinations using a 3.0 T MRI scanner. Intergroup differences in regional and global CBF and white matter hyperintensities (WMHs) were analyzed.

RESULTS

In this study, 100 (74 males) of 750 (439 males) subjects were diagnosed with OSA, so the prevalence of OSA in the general population was 13.3% (100/750), with 16.9% (74/439) in males and 8.4% (26/311) in females. Excluding four patients with incomplete imaging data, 96 OSA patients and 103 age- and sex-matched NSA subjects were included. At global level, OSA patients showed significantly decreased CBF values in gray matter and whole brain compared to NSA subjects (gray matter: p = 0.010; whole brain: p = 0.021). No significant difference in CBF values was found in WM between the two groups (p = 0.250). At regional level, compared with NSA subjects, patients with OSA exhibited significantly decreased regional CBF values mainly in right parietal lobe and right temporal lobe. Moreover, OSA patients had significantly higher WMHs burden than NSA subjects (p = 0.017).

CONCLUSIONS

OSA patients exhibit decreased global and regional CBF values and increased WMHs burden.

ADVANCES IN KNOWLEDGE

These findings provide a basis for exploring neuropathological changes of OSA and for early and appropriate treatment.

Proteomic profiling for prediction of recurrent cardiovascular event in patients with acute coronary syndrome and obstructive sleep apnea: A post-hoc analysis from the ISAACC study

BACKGROUND

Obstructive sleep apnea (OSA) is associated with a recurrent cardiovascular event (CVE) risk in patients with a first acute coronary syndrome (ACS). However, the pathological pathways by which OSA promotes this deleterious role are unknown. We aim to explore the proteomic profile associated with OSA that promote the recurrent CVE risk in severe OSA patients with ACS without previous cardiovascular diseases.

METHODS

This post-hoc analysis from the ISAACC study (NCT01335087) included 86 patients admitted for ACS. Patients underwent respiratory polygraphy for the first 24-72 h to OSA diagnosis. We analyzed of 276 cardiovascular and inflammatory related proteins in baseline fasting plasma samples using proximity expression assay technology (Olink®, Sweden). Protein levels were compared between severe OSA patients with/without recurrent CVEs during follow-up. Random forest was conducted to select relevant proteins and generate a predictive model of recurrent CVE.

RESULTS

We included 86 patients (median age: 61 years, median BMI: 29.4 kg/m² and 86 % males) admitted for ACS with severe OSA (56 without recurrent CVE/30 with recurrent CVE). The plasma levels of 38 proteins were differentially expressed between groups. Additionally, 12 proteins had a significant association with respiratory polygraphy parameters. Three proteins discriminate with an AUC of 0.81 (95 % CI of 0.71-0.9) between severe OSA patients with and without recurrent CVE. These proteins were implicated in cell proliferation, communication and apoptosis, and regulation/response to the inflammatory and immune systems.

CONCLUSION

In ACS patients with severe OSA, a proteomic profile was associated with recurrent CVEs. This proteomic profile was correlated with specific OSA parameters from respiratory polygraphy. Proteomic profiling may provide an new direction for patient risk stratification and clinical management.

The Need for Glaucoma Management in Glaucoma Patients with Concurrent Obstructive Sleep Apnea: A Population-Based Cohort Study

We try to evaluate glaucoma management numbers in patients with both glaucoma and obstructive sleep apnea (OSA) using the National Health Insurance Research Database (NHIRD) of Taiwan. A retrospective cohort study was conducted and patients with glaucoma were enrolled and divided into the OSA and non-OSA populations. A total of 11,778 participants were selected in both the OSA and non-OSA groups. The primary outcomes were the number of anti-glaucomatous medications each year and the total number of glaucoma laser and glaucoma surgeries. The Cox proportional hazard regression was utilized to produce the adjusted hazard ratios (AHR) with corresponding 95% confidence intervals (CI) between the two groups. After a study period of 18 years, 286 and 352 events of laser and surgeries for glaucoma were found in the OSA and non-OSA groups, respectively. After considering the effect of potential confounders, no significant difference concerning the numbers of laser trabeculoplasty, trabeculectomy and tube shunt surgery, cyclodestructive procedure and eyeball removal were found between the two groups (all 95% CIs included one). In addition, the multiple anti-glaucomatous medication usages were similar between the two groups (all p > 0.05) In the subgroup analyses, glaucoma patients older than 60 years and with OSA received significantly lesser trabeculectomy and tube shunt surgery compared to glaucoma patients older than 60 years without OSA (AHR: 0.774, 95% CI: 0.611−0.981) while other analyses revealed insignificant results (all 95% CIs included one). In conclusion, the presence of OSA does not increase the need for glaucoma management.

Symptoms and Risk of Obstructive Sleep Apnea in Patients Attending Primary Health Care Clinics in Riyadh, Saudi Arabia

Background Obstructive sleep apnea (OSA) is a breathing disorder that occurs while sleeping, characterized by periods of partial or complete airway collapse associated with a drop in oxygen saturation or arousal from sleep. OSA is associated with significant health consequences, including hypertension, obesity, coronary artery disease, metabolic dysfunction, cognitive decline, and cancer progression. Methods A cross-sectional study was conducted at the four primary healthcare centers in the Ministry of National Guards Health Affairs (MNGHA) in Riyadh, Saudi Arabia. The study included every adult 18- 65 years old. After informed consent was obtained, interviews were conducted using the Berlin questionnaire (BQ) to assess participants' prevalence and risk (OSA). SAS software version 9.4 was used to enter and analyze the data.  Results A total of 400 primary care attendants were approached. The overall prevalence of high-risk apnea was 21%. There was a significant difference in the high risk of apnea between a BMI greater than 30 and a BMI lower than 30 (p< 0.0001). There was a significant difference in the high risk of apnea between hypertension and normal blood pressure (p< 0.0001). Conclusion The BQ assessed the predictive factors related to the development and prevalence of OSA and showed a predominance in those with a BMI over 30 Kg/m² or with a previous diagnosis of hypertension with no significant related risk among gender and age factors.

Alterations of cholesterol synthesis and absorption in obstructive sleep apnea: Influence of obesity and disease severity

BACKGROUND AND AIMS

Obstructive sleep apnea (OSA) is closely linked to obesity and related adverse metabolic changes, including dyslipidemia. However, it is not clear whether OSA is an independent contributing factor to dyslipidemia, or the observed association is a reflection of a concomitant presence of obesity. Additionally, dyslipidemia is usually evaluated through measurement of parameters of routine lipid status, while more precise evaluation of lipid homeostasis is rarely performed in OSA. In this study, we analyzed markers of cholesterol synthesis and absorption in patients with OSA with respect to the presence of obesity and the disease severity.

METHODS AND RESULTS

This study enrolled 116 OSA patients. Concentrations of non-cholesterol sterols (NCS), measured by LC-MS/MS, were used as markers of cholesterol synthesis and absorption. Apnea-hypopnea index (AHI) and oxygen saturation (SaO₂) were utilized as markers of OSA severity. Serum lipid status parameters were determined by routine enzymatic methods. Markers of cholesterol synthesis were increased (P = 0.005), whilst markers of cholesterol absorption decreased (P = 0.001) in obese OSA patients. Cholesterol synthesis/absorption ratio was elevated in obese subjects (P < 0.001). Concentration of cholesterol synthesis marker lathosterol was significantly higher in subjects with severe OSA (P = 0.014) and we observed a trend of decreased cholesterol absorption in these patients. AHI was revealed as an independent determinant of lathosterol concentration (P = 0.022).

CONCLUSIONS

Our results suggest that the presence of obesity and severe forms of OSA is characterized by elevated endogenous cholesterol synthesis. AHI was singled out as an independent determinant of the serum level of cholesterol synthesis marker lathosterol.

Prevalence of silent atrial fibrillation and cardiovascular disease in patients with obstructive sleep apnea

OBJECTIVE

Patients with silent and undiagnosed atrial fibrillation (AF) have increased risk of ischemic stroke. Patients with obstructive sleep apnea (OSA) have an increased risk of both AF and ischemic stroke. Our aim was to investigate the prevalence of silent AF and associated risk factors in patients investigated for OSA or with known OSA.

METHODS

This prospective observational study was performed in two sites; one outpatient sleep-clinic at Zealand University Hospital and one private Ear-Nose- and Throat clinic. Patients were investigated with a type-3 portable sleep-monitoring device, while heart rhythm was home-monitored for 7 days with an event-triggered loop recorder. Patients were stratified in groups of mild, moderate and severe OSA based on Apnea-Hypopnea-Index (AHI).

RESULTS

In a cohort of 303 patients, 238 (78.5%) were diagnosed with moderate/or severe OSA and 65 (21.5%) with no/mild OSA who constituted the control group. In 238 patients with moderate and severe OSA, AF was detected in 21 patients (8.8%) vs. 1 patient (1.5%,[p=0.045]) with mild OSA. Candidates for anticoagulation therapy were referred for further cardiovascular treatment. The majority of patients had known hypertension (n = 200,66%) and dyslipidemia (n = 235,[77.6%]) In patients with moderate/or severe OSA (AHI≥15), hypertension was more dysregulated (p=0.005) and more patients suffered from unknown prediabetes (n = 36, 3.1% vs. 14.3%[p<0.001]).

CONCLUSION

Undiagnosed AF and undertreated cardiovascular modifiable risk factors are common in a cohort of patients with OSA. With this study we propose that long-period home-monitoring in these patients is useful for identifying candidates for preventive anticoagulation, cardiovascular treatment and possibly prevent future ischemic stroke.

Construction of a mitochondrial dysfunction related signature of diagnosed model to obstructive sleep apnea

Background: The molecular mechanisms underlying obstructive sleep apnea (OSA) and its comorbidities may involve mitochondrial dysfunction. However, very little is known about the relationships between mitochondrial dysfunction-related genes and OSA. Methods: Mitochondrial dysfunction-related differentially expressed genes (DEGs) between OSA and control adipose tissue samples were identified using data from the Gene Expression Omnibus database and information on mitochondrial dysfunction-related genes from the GeneCards database. A mitochondrial dysfunction-related signature of diagnostic model was established using least absolute shrinkage and selection operator Cox regression and then verified. Additionally, consensus clustering algorithms were used to conduct an unsupervised cluster analysis. A protein-protein interaction network of the DEGs between the mitochondrial dysfunction-related clusters was constructed using STRING database and the hub genes were identified. Functional analyses, including Gene Ontology (GO) analysis, Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis, gene set enrichment analysis (GSEA), and gene set variation analysis (GSVA), were conducted to explore the mechanisms involved in mitochondrial dysfunction in OSA. Immune cell infiltration analyses were conducted using CIBERSORT and single-sample GSEA (ssGSEA). Results: we established mitochondrial dysfunction related four-gene signature of diagnostic model consisted of NPR3, PDIA3, SLPI, ERAP2, and which could easily distinguish between OSA patients and controls. In addition, based on mitochondrial dysfunction-related gene expression, we identified two clusters among all the samples and three clusters among the OSA samples. A total of 10 hub genes were selected from the PPI network of DEGs between the two mitochondrial dysfunction-related clusters. There were correlations between the 10 hub genes and the 4 diagnostic genes. Enrichment analyses suggested that autophagy, inflammation pathways, and immune pathways are crucial in mitochondrial dysfunction in OSA. Plasma cells and M0 and M1 macrophages were significantly different between the OSA and control samples, while several immune cell types, especially T cells (γ/δ T cells, natural killer T cells, regulatory T cells, and type 17 T helper cells), were significantly different among mitochondrial dysfunction-related clusters of OSA samples. Conclusion: A novel mitochondrial dysfunction-related four-gen signature of diagnostic model was built. The genes are potential biomarkers for OSA and may play important roles in the development of OSA complications.

Carbonic Anhydrase IX as a Marker of Disease Severity in Obstructive Sleep Apnea

Background and Objectives: Carbonic anhydrase (CA) enzymes are a family of metalloenzymes that contain a zinc ion in their active sites. CA enzymes have been implied in important situations such as CO2 transport, pH regulation, and oncogenesis. CA-IX is a transmembrane glycoprotein and stimulates the expression of hypoxia-inducible factor-1 (HIF-1) CA-IX. This study aimed to determine serum CA-IX levels in OSA patients in whom intermittent hypoxia is important and to investigate the relationship between serum CA-IX levels and disease severity. Materials and Methods: The study included 88 people who applied to Malatya Turgut Özal University Training and Research Hospital Sleep Disorders Center without a history of respiratory disease, malignancy, and smoking. Patients were divided into three groups: control (AHI < 5, n = 31), mild−moderate OSA (AHI = 5−30, n = 27) and severe OSA (AHI > 30, n = 30). The analysis of the data included in the research was carried out with the SPSS (IBM Statistics 25, NY, USA). The Shapiro−Wilk Test was used to check whether the data included in the study had a normal distribution. Comparisons were made with ANOVA in multivariate groups and the t-test in bivariate groups. ANCOVA was applied to determine the effect of the CA-IX parameter for OSA by controlling the effect of independent variables. The differentiation in CA-IX and OSA groups was analyzed regardless of BMI, age, gender, and laboratory variables. ROC analysis was applied to determine the parameter cut-off point. Sensitivity, specificity, and cut-off were calculated, and the area under the curve (AUC) value was calculated. Results: Serum CA-IX levels were 126.3 ± 24.5 pg/mL in the control group, 184.6 ± 59.1 pg/mL in the mild−moderate OSA group, and 332.0 ± 39.7 pg/mL in the severe OSA group. Serum CA-IX levels were found to be higher in the severe OSA group compared to the mild−moderate OSA group and control group and higher in the mild−moderate OSA group compared to the control group (p < 0.001, p < 0.001, p < 0.001, respectively). In addition, a negative correlation between CA-IX and minimum SaO2 and mean SaO2 (r = −0.371, p = 0.004; r = −0.319, p = 0.017, respectively). A positive correlation between CA-IX and desaturation index (CT90) was found (r = 0.369, p = 0.005). A positive correlation was found between CA-IX and CRP (r = 0.340, p = 0.010). When evaluated by ROC curve analysis, the area under the curve (AUC) value was determined as 0.940 (95% CI 0.322−0.557; p < 0.001). When the cut-off value for CA-IX was taken as 254.5 pg/mL, it was found to have 96.7% sensitivity and 94.8% specificity in demonstrating severe OSA. Conclusions: Our study found that serum CA-IX value was higher in OSA patients than in control patients, and this elevation was associated with hypoxemia and inflammation. CA-IX value can be a fast, precise, and useful biomarker to predict OSA.

The critical issue linking lipids and inflammation: Clinical utility of stopping oxidative stress

The formation of an atheroma begins when lipoproteins become trapped in the intima. Entrapped lipoproteins become oxidized and activate the innate immune system. This immunity represents the primary association between lipids and inflammation. When the trapping continues, the link between lipids and inflammation becomes chronic and detrimental, resulting in atherosclerosis. When entrapment ceases, the association between lipids and inflammation is temporary and healthy, and the atherogenic process halts. Therefore, the link between lipids and inflammation depends upon lipoprotein retention in the intima. The entrapment is due to electrostatic forces uniting apolipoprotein B to polysaccharide chains on intimal proteoglycans. The genetic transformation of contractile smooth muscle cells in the media into migratory secretory smooth muscle cells produces the intimal proteoglycans. The protein, platelet-derived growth factor produced by activated platelets, is the primary stimulus for this genetic change. Oxidative stress is the main stimulus to activate platelets. Therefore, minimizing oxidative stress would significantly reduce the retention of lipoproteins. Less entrapment decreases the association between lipids and inflammation. More importantly, it would halt atherogenesis. This review will analyze oxidative stress as the critical link between lipids, inflammation, and the pathogenesis of atherosclerosis. Through this perspective, we will discuss stopping oxidative stress to disrupt a harmful association between lipids and inflammation. Numerous therapeutic options will be discussed to mitigate oxidative stress. This paper will add a new meaning to the Morse code distress signal SOS-stopping oxidative stress.